This study aimed to optimize through design of experiments, the process variables (temperature - T, time - t and solid-to-liquid ratio - SLR) for sugarcane bagasse (SB) autohydrolysis (AH) to obtain hemicellulose hydrolyzates (HH) prone to anaerobic digestion (AD) and biochemical methane production (BMP). The results indicated that severe AH conditions, which lead to maximum hemicelluloses dissolution and sugar content in the HH, were not the best for BMP, probably due to the accumulation of toxic/recalcitrant compounds (furans and lignin). Mild AH conditions (170 degrees C, 35 min and SLR = 0.33) led to the highest BMP (0.79 Nm(3) kg TOC (1)), which was confirmed by the desirability tool. HH produced by AH carried out at the desired condition DC2 (178.6 degrees C, 43.6 min and SLR = 0.24) showed the lowest accumulation of inhibitory compounds and volatile fatty acids (VFA) and highest BMP (1.56 Nm(3) kg TOC (1)). The modified Gompertz model best fit the experimental data and led to a maximum methane production rate (R) of 2.6 mmol CH4 d (1) in the best condition. (C) 2015 Elsevier Ltd. All rights reserved.
This work describes the preparation of new chelating materials derived from cellulose and sugarcane bagasse for adsorption of Cu2+, Cd2+, and Pb2+ ions from aqueous solutions. The first part involved the mercerization treatment of cellulose and sugarcane bagasse with NaOH 5 mol/L Non- and mercerized cellulose and sugarcane bagasse were then reacted with ethylenediaminetetraacetic dianhydride (EDTAD) in order to prepare different chelating materials. These materials were characterized by mass percent gain, X-ray diffraction, FTIR, and elemental analysis. The second part consisted of evaluating the adsorption capacity of these modified materials for Cu2+, Cd2+, and Pb2+ ions from aqueous single metal solutions, whose concentration was determined by atomic absorption spectroscopy. These materials als showed maximum adsorption capacities for Cu2+, Cd2+, and Pb2+ ions ranging from 38.8 to 92.6 mg/g, 87.7 to 149.0 mg/g, and 192.0 to 333.0 mg/g, respectively. The modified mercerized materials showed larger maximum adsorption capacities than modified non-mercerized materials. (C) 2009 Elsevier Ltd. All rights reserved.
This study was undertaken not only to evaluate detoxification impact vs. adaptation on ethanologenic fermentation but also to optimize the fermentation condition to produce ethanol from Sugarcane Bagasse Hydrolysate (SBH). Detoxification by over-liming significantly improved the fermentability of the Concentrated Sugarcane Bagasse Hydrolysate (CSBH) by a wild strain of Barnettozyma californica. Compared to non-detoxified CSBH, ethanol production by the wild type strain increased from 1.233 g L-1 to 3.8031 g L-1, after 32 h and 24 h fermentation, respectively. Detoxification of SBH and CSBH showed a reverse effect on the adapted yeast. In detoxified CSBH, fermentation time increased to 32 h (3.084 g L-1) by adapted strain, while ethanol production was 3.803 g L-1 after 24 h by the non-adapted strain. Also, it should be noted that the parental yeast's capacity was found to be practicable in SBH without a detoxification and adaptation process. The screening and opti-mization of process parameters and critical medium components were done using the Plackett-Burman and Box-Behnken experimental design, respectively. (NH4)(2)SO4, (NH4)(2)PO4, ZnCl2, hydrolysate concentration, in-cubation temperature, and flask volume were found to be the main factors affecting ethanol production. Finally, a yield of 0.44 g g(-1) was obtained, which is almost twice as high as the non-optimized medium. Taken together, these results indicate that hydrolysate detoxification and yeast adaptation through adaptive evolution and me-dium optimization are effective methods to overcome the bottleneck of lignocellulosic ethanol production.
Sugarcane industry is a major agricultural sector capable of producing sugars with byproducts including straw, bagasse, and molasses. Sugarcane byproducts are no longer wastes since they can be converted into carbon-rich resources for biorefinery if pretreatment of these is well established. Considerable efforts have been devoted to effective pretreatment techniques for each sugarcane byproduct to supply feedstocks in microbial fermentation to produce value-added fuels, chemicals, and polymers. These value-added chains, which start with low-value in-dustrial wastes and end with high-value products, can make sugarcane-based biorefinery a more viable option for the modern chemical industry. In this review, recent advances in sugarcane valorization techniques are pre-sented, ranging from sugarcane processing, pretreatment, and microbial production of value-added products. Three lucrative products, ethanol, 2,3-butanediol, and polyhydroxyalkanoates, whose production from sugar-cane wastes has been widely researched, are being explored. Future studies and development in sugarcane waste biorefinery are discussed to overcome the challenges remaining.
Co-briquetting of coal fines and lignocellulosic biomass is a possible path for incorporating biomass energy into the current coal-based infrastructure, although the cost and performance of conventional binders remain problematic. The use of steam-exploded sugarcane bagasse (SE SCB) as a binder for coal fines briquetting was therefore investigated. SE SCB (produced at 140-220 degrees C for 15 min) was mixed with high-ash bituminous coal-fines at various concentrations (0-18\%), and briquetted at a pressure value of 24 MPa and at various temperatures (25-180 degrees C). Following multivariate optimization, an optimal steam explosion temperature range of 185-195 degrees C was found. At these pretreatment temperatures, sufficient disruption of the lignocellulosic structure occurred, resulting in increased binding between coal fines and SCB, while higher temperatures resulted in detrimental destruction of fiber structure and reduction in binding performance. A synergistic interaction between briquetting temperatures and SE SCB content above 100 degrees C and 13\%, respectively, substantially improved briquette properties. At these optimum conditions, the briquettes had a compressive strength of 1205 kPa, an abrasion resistance of 97\%, water absorption index of 82\%, and a wet compressive strength of 501 kPa. Briquettes maintained structural integrity when pyrolyzed at 700 degrees C and had a post-pyrolysis compressive strength of 134 kPa, indicating that SE SCB could potentially be a suitable binder for coal fines briquetting.
The sustainability of a biofuel is severely affected by the technological route of its production. Chemical pretreatment can be considered the traditional method of decomposition of the lignocellulose into its mono and oligomeric units, which can be further bioconverted to ethanol. The evaluation of the recent advances in chemical pretreatments of sugarcane bagasse, especially diluted acids, alkaline, organosolv and ionic liquids, identified the critical points for sustainability. In this context, chemicals recovery and reutilization or their substitution by green solvents, heat and electricity generation through bioenergy, reutilization of water from evaporators, vinasse concentration and the upgrading of lignin were discussed as strategic routes for developing sustainable chemical-based lignocellulose pretreatment. The advances in the technologies that allow greater fractionation of lignocellulosic biomass should be focused on the minimization of the use of natural resources, effluent generation and energy expenditure.
In a pot experiment with corn (Zea mays L. cv. Moncada) and an incubation study, ash from co-combustion of sugarcane bagasse and eucalyptus wood was evaluated for use as a potential alternative to conventional agricultural limestone. Ash was effective as liming agent. Soil pH increased from 5.1 to 5.9 in a Haplic Arenosol and from 5.3 to 6.0 in a Haplic Cambisol. pH of the ash-amended soils were similar to those amended with calcitic and dolomitic limestone. Soil extractable P and K increased by 254\% and 869\% in the Haplic Cambisol and by 183\% and 208\% in the Haplic Arenosol. Application of ash to soil was associated with an increase in corn yield of 32\% in the Haplic Cambisol and 11\% in the Haplic Arenosol relative to the unamended treatments. The uptake of K by corn was greatly enhanced after ash application, increasing from 319 to 1079 mg K pot(-1) in the Haplic Cambisol and from 397 to 729 mg K pot(-1) in the Haplic Arenosol. Results supported the view that ash is a by-product that can become an increasingly valuable amendment as it acts both as a liming material and as a P and K fertilizer.
The expansion of sugarcane cultivation in the Center-South region of Brazil has led to the use of, mainly, areas with low-yielding sandy soils. In this context, the objectives of this study were to evaluate the maintenance of the sugarcane straw, Brachiaria grass intercropping in sugarcane fields and nitrogen fertilization and on sandy soils in the state of Parana. The field experiment was installed in the Paranavai-PR city, at a unit of the Interuniversity Network for the Development of the Sugarcane Sector (RIDESA). The soil was classified as Latossolo Vermelho-amarelo distrafico. The treatments in the plant cane stage, consisting of four nitrogen rates (0, 50, 100 and 150 kg ha and monoculture or Brachiaria grass intercropping in sugarcane fields were arranged in a 4x2 factorial design. At plant cane harvest, the effect of unremoved straw was included as a new factor to be evaluated in the ratoon crops. The treatments in the ratoon crops were arranged in a 4x2x2 factorial design, consisting of four nitrogen rates (0, 50, 100 and 150 kg ha(-1)), monoculture or Brachiaria grass intercropping in sugarcane fields and the presence or removal sugarcane straw. The sugarcane straw on soil surface can increase the agronomic development of sugarcane and, the other hands, Brachlaria grass intercropping in sugarcane fields can reduce. Sugarcane was responsive to N rates and, in the highest rates, compensated the sugarcane straw absence and reduced Brachiaria grass intercropping competition.
Sugarcane bagasse was used as a carrier material of microorganisms in two different biofilters used to remove dimethyl sulfide (DMS) from a gas stream. The first biofilter was inoculated with Hyphomicrobium VS and the second with Thiobacillus thioparus Tk-m. During the operation of the biofilters the empty bed residence time (EBRT) was varied from 90 to 180 seconds and the inlet concentration of DMS from 12 to 50 ppmv. The inlet load was varied in the range of 0.62 to 5.2 (g DMS/m3 h). The maximum elimination capacity (EC) of the biofilter inoculated with Hyphomicrobium VS was 5 g DMS/m3 h; however, for the biofilter inoculated with T. thioparus Tk-m the maximum EC was 3.9 g DMS/m3 h. For T. thioparus TK-m the maximum removal efficiency (RE) obtained was 85.1 +/- 5.2\% at 12 ppmv DMS inlet concentration, inlet load of 0.62 g DMS/m 3 h and 180 s EBRT. The highest removal efficiency for Hyphomicrobium VS was 97.6 +/- 4.8\% at 12 ppmv DMS inlet concentration, load of 0.62 g DMS/m 3h and 180 s EBRT.
Background: New biorefinery concepts are necessary to drive industrial use of lignocellulose biomass components. Xylan recovery before enzymatic hydrolysis of the glucan component is a way to add value to the hemicellulose fraction, which can be used in papermaking, pharmaceutical, and food industries. Hemicellulose removal can also facilitate subsequent cellulolytic glucan hydrolysis. Results: Sugarcane bagasse was pretreated with an alkaline-sulfite chemithermomechanical process to facilitate subsequent extraction of xylan by enzymatic or alkaline procedures. Alkaline extraction methods yielded 53\% (w/w) xylan recovery. The enzymatic approach provided a limited yield of 22\% (w/w) but produced the xylan with the lowest contamination with lignin and glucan components. All extracted xylans presented arabinosyl side groups and absence of acetylation. 2D-NMR data suggested the presence of O-methyl-glucuronic acid and p-coumarates only in enzymatically extracted xylan. Xylans isolated using the enzymatic approach resulted in products with molecular weights (Mw) lower than 6 kDa. Higher Mw values were detected in the alkali-isolated xylans. Alkaline extraction of xylan provided a glucan-enriched solid readily hydrolysable with low cellulase loads, generating hydrolysates with a high glucose/xylose ratio. Conclusions: Hemicellulose removal before enzymatic hydrolysis of the cellulosic fraction proved to be an efficient manner to add value to sugarcane bagasse biorefining. Xylans with varied yield, purity, and structure can be obtained according to the extraction method. Enzymatic extraction procedures produce high-purity xylans at low yield, whereas alkaline extraction methods provided higher xylan yields with more lignin and glucan contamination. When xylan extraction is performed with alkaline methods, the residual glucan-enriched solid seems suitable for glucose production employing low cellulase loadings.
Textile dye effluents have many deleterious effects; therefore, it is essential to remove before releasing into waterbodies. This study developed a two-step process for decolorization of textile dye using sugarcane bagasse (SCB). The first step of the process involved functionalization of SCB with alginic acid and applying as packing material in column and assessing its performance for adsorptive removal of Drimarene red. The designed column showed 90\% removal of the dye in dye-aqueous solution whereas 80\% removal in dye-house wastewater. Adsorption capacity was increased at first 10 min and then gradually decreased with time. Breakthrough point was not achieved during the 60 min of experiment. Three non-equilibrium models were applied to understand the column bed properties. In the second step, the adsorbed dye molecules in SCB were degraded using an edible fungus Pleurotus sp. to obtain a dye-free nitrogen-rich bagasse. The fungus-treated SCB showed no residual toxicity and a considerable improvement in nitrogen content (from 0.14\% to 0.62\%) was noticed after the study of elemental profile. New design of the column bed, the processes of the chemical functionalization of the SCB, and bioremediation of dye treated bagasse through Pleurotus sp. offer a novel solution for efficient and safe disposal of textile dyes. Practitioner Points Two-step process for remediation of a textile dye using an agrowaste and Pleurotus sp. Chemical functionalization of an agrowaste for enhanced dye removal. New process of adsorption-fungal degradation for safe disposal of the dyes. Novel technology for a sustainable use of the agrowaste for environmental safety.
Xylooligosaccharides (XOS) are emerging as highly effective but expensive products in the global pre biotics market. The need for biomass pretreatment and the low efficiency of subsequent enzymatic hydrolyses limit XOS yield from lignocellulosic biomass. In this study, a sequential three-step process of mild chemical pretreatment of sugarcane bagasse (SB) with potassium hydroxide followed by pretreatment with phosphoric acid and then hydrolysis with endo-xylanase was developed for producing XOS. The novel process resulted in a maximum XOS (xylobiose {[
Saccharum officinarum L. exploitation and processing result in different byproducts, such as filter cake (FC). This study aimed to establish the most suitable experimental conditions to obtain lipophilic bioactive compounds from FC industrial residues, considering their high efficiency, cost-effectiveness, extraction yield, composition, and physicochemical properties. Results indicated that the most appropriate methodology consisted of the pretreatment of the FC sample with H2SO4, followed by ethanolic extraction (B6 method), avoiding energy-consumption FC drying steps and providing ethanol recovery (approx. 90\%). The obtained B6 extract yield was 9.59 \& PLUSMN; 0.27 g/100 g of FC dry weight, and this methodology proved to be more efficient in obtaining fatty alcohols (20.28 \& PLUSMN; 1.48 g/kg extract) and phytosterols (31.56 \& PLUSMN; 0.18 g/kg extract) while maintaining lower total monosaccharide concentration (26.19 \& PLUSMN; 1.82 mg/g extract). Furthermore, the geographically related multivariate analysis in wax composition and antioxidant activity was evaluated by comparing B6 waxes from Guariba (G) and Univalem (U), both provided by Brazil and collected in June 2020. Overall, the wax composition is affected, but the antioxidant activity is uncompromised, which indicates that the optimized wax extraction method can be applied to FC.
Fed-batch enzymatic hydrolysis process from alkali-pretreated sugarcane bagasse was investigated to increase solids loading, produce high-concentration fermentable sugar and finally to reduce the cost of the production process. The optimal initial solids loading, feeding time and quantities were examined. The hydrolysis system was initiated with 12\% (w/v) solids loading in flasks, where 7\% fresh solids were fed consecutively at 6 h, 12 h, 24 h to get a final solids loading of 33\%. All the requested cellulase loading (10 FPU/g substrate) was added completely at the beginning of hydrolysis reaction. After 120 h of hydrolysis, the maximal concentrations of cellobiose, glucose and xylose obtained were 9.376 g/L, 129.50 g/L, 56.03 g/L, respectively. The final total glucan conversion rate attained to 60\% from this fed-batch process. (C) 2014 Published by Elsevier Ltd.
This work is the first report on use of carbonized sugarcane bagasse as a carbon bed for a double Bronsted acidic ionic liquid for the synthesis of a new functionalized solid acid catalyst. Immobilization of hydrogen sulfate was performed from the reaction of 3-amino propyltriethoxysilane with carbonized bagasse and sulfonation of amine groups using sulfuric acid. Thus, ammonium hydrogen sulfate supported sugarcane bagasse (AHS@CSCB) was prepared. The catalyst (AHS@CSCB) was fully characterized by FT-IR, XRD, TGA, FE-SEM, elemental-mapping and EDX techniques. Also, the surface acidity of catalyst was studied by Hammett function. Catalytic properties of the synthesized catalyst were examined in the synthesis of coumarins, dicoumarols and dibenzoxanthenes. All of the products were obtained with high yields in short reaction times and solvent-free conditions and characterized with H-1 and (CNMR)-C-13 or previously reported products were examined by comparison with reported melting points. Some of the advantages of our method are simple preparation of catalyst and safe handling, very low cost of support and its abundance, high products yield, catalyst recyclability, solvent-free and easy workup.
Co-pyrolysis of sugarcane bagasse (SCB) with waste high-density polyethylene (HDPE) was performed in a fixed-bed reactor under different temperatures (400-700 degrees C) and blending ratios (0-100\%). Product yields and chemical compositions were compared with those from the pyrolysis of individual components to ascertain the synergistic effect between SCB and HDPE. The synergistic effect of SCB and HDPE produced higher liquid yield than the theoretical value. The effect was strongest at 600 degrees C and 60:40 HDPE:SCB ratio, with the maximum difference of 6.02 wt\%. The positive synergistic effects on the production of high-value organic compounds (alcohol, hydrocarbons, and aromatics) and inhibition of oxygenated compounds were most prominent at 600 degrees C and 40:60 HDPE:SCB ratio. SCB-derived hydroxyl radicals favored the secondary cracking of HDPE primary volatiles, thereby promoting the formation of aliphatic compounds with lower carbon numbers. Co-pyrolysis of SCB and HDPE also produced oil with higher carbon (34\% higher) and hydrogen (47\% higher) contents, and with lower oxygen content (70\% lower) than those of SCB pyrolysis oil. It also achieved a high calorific value of 42.41 MJ/kg, which is comparable to those of commercial diesel fuels. (C) 2019 Elsevier Ltd. All rights reserved.
In this study, sugarcane bagasse (2 mm) was pretreated with 2.5\% NaOH followed by steaming at 121 degrees C for various time periods. Maximum cellulose content of 81\% and delignification of 68.5\% were achieved by soaking bagasse in 2.5\% NaOH with a residence time of 1 h at room temperature followed by steaming at 121 degrees C for 30 min residence time. The pretreated substrate was analyzed by SEM and FTIR to study the structural modification and functional group of the untreated and pretreated substrates. The pretreated substrate was saccharified by commercial cellulase enzyme depicting 106 mu m mesh size of substrate yields maximum saccharification rate. The saccharified material was fermented by Saccharomyces cerevisiae and Pichia stipitis in mono-and co-culture modes. Maximum product yield (Y-p/5) was observed by monoculture using Saccharomyces cerevisiae after 96 h of fermentation period.
Cements with low clinker content are an important alternative for sustainable development of the cement industry. In this respect, the present study aimed the production and characterization of binary and ternary mixes of cement, sugarcane bagasse ash (SCBA) and limestone in order to assess the physical and chemical effects of these materials in cementitious systems. Pastes and mortars were produced using the different cements to assess their performance in rheology, isothermal calorimetry, chemical shrinkage, and compressive strength tests. All cements with SCBA were characterized as pozzolanic Portland cements, justifying the increase in chemical shrinkage in relation to the reference. Adding both materials changed the rheology of mixes, increasing rheological parameters, primarily in pastes with SCBA. Limestone accelerated hydration during the first few days due to the heterogeneous nucleation effect, but compressive strength declined at 7, 28, and 90 days owing to the dilution effect. SCBA initially delayed paste hydration, but increased compressive strength compared to the reference at all studied ages due to pozzolanic reactions. The performance of ternary mixes was intermediate in relation to binary SCBA-cement and limestone-cement, suggesting the joint effect of the additions on the properties assessed.
The use of biomass in cogeneration is a sustainable alternative of energy production, allowing replacing fossil fuels and reduction of greenhouse gas emissions. This work discloses an integrated process analyzer framework comprising surrogate models for estimation of fixed capital investment, revenues, costs of manufacturing as well as several performance responses of cogeneration units of sugarcane-biorefineries burning bagasse, with/without post-combustion carbon capture and storage. A restricted number of inputs are required, namely bagasse availability and heat requirements of the sugarcane-biorefinery. To develop the investment models, a 33 factorial computational-experimental design was performed, where AspenOne Portfolio was used in each run to simulate the process allowing estimating the fixed capital investment. Surrogate models were adjusted to fit capital estimates, resulting in 1.9\% and 1.3\% mean errors for the cogeneration and the post-combustion capture steps, respectively. Capture costs were estimated by analytical equations using the investment values and other estimates from the process analyzer framework, reaching 262 USD/t, but can be as low as 17.2 USD/t if limitations from the agricultural sector are disregarded; namely seasonality, operating time and capacity. The developed framework can assist in sugarcane-biorefinery investment decision making regarding bioenergy with carbon capture and storage or to develop carbon mitigation policies.
Wood bottom ash (WBA) is a type of wood waste ash produced as a by-product from the incineration or combustion from wood-fired power plants, pulp and paper and wood-burning industrial facilities. It is the fraternal twin of the most common and popular fly-ash which is obtained from the same process. Most of the WBA produced are disposed in landfills while few quantities of it are being used as supplementary cementitious materials (SCM) because of their pozzolanic activities. Several studies have been published to evaluate generally the use of wood waste and fly ashes as construction materials but the use of WBA as an entity has not found prominent attention when compared with the former. This review gives a comprehensive report of the factors determining the performance of WBA as cementitious material, physio-chemical characteristics of the ash, performance assessment of WBA on some cementitious properties, occupational hazard associated with WBA when used as a construction material and comparison with wood fly-ash and lastly the comparison of engineering properties between WBA and other major ashes used as SCMs' for construction purposes. The other ashes considered and compared with WBA were wood fly ash (FA1), sugarcane bagasse ash (SB1), rice husk ash (RH1), palm-oil ash (PO1), coal fly ash (CA1), coal bottom ash (CA2), municipal solid waste ash (SW1), bamboo leaf ash (BL) and waste paper sludge ash (WP). The findings revealed that inclusion of WBA at an optimum level in cement-based materials is valuable to sustainable development as well as for waste management.
The benefits of amending soil,vith cellulosic organic wastes generated during the processing of agricultural products are limited by their low nutrient value, occasional strong odors, and high costs of transportation. The objective of this study was to develop a chemical process to enrich the N content and reduce the water content of cellulosic organic wastes to enhance their value as nutrient supplements. Various combinations of pressure (300-9000 kPa), temperature (60-240 degrees C), and O-2 and NH3 concentrations were used to identify optimal parameters for N enrichment of various wastes by reaction with anhydrous NH3. Total N contents of sugarcane (Saccharum officinarum L.) milling wastes, rice (Oryza sativa L.) hulls, and several composts were increased 5.9 to 17.1 times under the optimal combination of reaction parameters tested. Ammoniation resulted in dry, dark brown. organic products containing 50 to 90 g N kg(-1) and having negligible odor. Nitrogen enrichment increased as the organic C content of the organic wastes increased. For all materials studied, the optimal N enrichment was obtained at a reactor pressure of 7200 kPa. Optimal reaction temperature varied between 80 and 180 degrees C. Maximum fixation was attained in <120 min for all materials studied. Products ammoniated under optimal conditions contained 87 to 93\% of their N as organic N. Increasing reaction temperature decreased the proportion of,vater soluble to insoluble organic N in ammoniated materials. Anaerobic incubation of soils amended with ammoniated bagasse indicated about 20\% of N in this material was released as mineral N within 14 d.
Xylanases are enzymes that convert xylan into xylose, xylobiose, and xylotriose. The present study deals with the production and optimization of xylanase through Solid-State Fermentation (SSF) using different agricultural wastes by Aspergillus spp. The Plackett Burman (PB) design was used to screen significant media components affecting the xylanase production. The carbon sources screened were wheat bran, rice bran, sugarcane bagasse, corn cob, and orange peel. The nitrogen sources screened were yeast extract, peptone, (NH4)(2)SO4, Na2NO3 and urea. Also, nine different salts such as KCl, MgSO4, Na2HPO4, CaCl2, FeSO4, ZnSO4, Na2CO3, KH2PO4, and NaH2PO4 which act as trace elements were screened. The results showed that wheat bran, yeast extract, Na2NO3 and KCI are the significant factors that affect xylanase production. A 3(3) Full Factorial Design (FFD) was performed to optimize the significant media components (wheat bran, KCI, yeast extract) obtained from PB design using Response Surface Methodology (RSM). Statistical analysis of results showed that wheat bran, KCI, yeast extract, and interaction between wheat bran and yeast extract were found to be significant. The optimum concentration of wheat bran, KCI, yeast extract was 8 g/L, 0.1 g/L and 3 g/L. The Partial purification of xylanase was carried out using ammonium salt precipitation and dialysis. Gel filtration chromatography was performed to optimize the elution time, which was found to be 6 minutes. Application of xylanase in orange juice clarification was studied at 40 degrees C, 50 degrees C, and 60 degrees C. The optimum temperature obtained was 60 degrees C.
Scientific community has paid attention to organic phase change materials (PCM) as a solution for the passive thermal management of buildings because they are chemically stable, phase transition range falls within thermal comfort range, non-toxic, non-corrosive, and readily available. However, low thermal conductivity and leakage problem during phase transitions are the primary limitations associated with organic PCM that require attention in order to use in many applications. In the present investigation, suitable materials (porous biochars) for providing shape stability to organic PCM have been systematically explored. Simple impregnation method has been used for the preparation of form-stable PCM green composites. The biochar is derived from three abundant biomass, namely, sugarcane bagasse (SCB), water hyacinth (WH), and yellow oleander (YO). Binary and ternary blends of three biochars derived from the mentioned biomasses have also been studied for their candidature as supporting matrix. The morphological and structural studies confirmed that the biochar is suitable for the encapsulation of melted PCM. The composites are compared based on the heat of fusion and thermal conduc-tivity. The highest heat of fusion is found to be 99 J/g for the PCM with a binary mixture of SCB and WH. It has been observed that thermal conductivity is highly dependent on the properties of the biochar matrix. Further-more, thermal conductivity is found to increase by 23 \% in the case of ternary mixture of biomass with PCM and decreased by 15.8 \% for the case of SCB with PCM mixture than that of the pure PCM, respectively.
The worldwide availability of lignocellulosic wastes represents a serious environmental challenge with potential opportunities. Xylanases are crucial in lignocellulosic bio-hydrolysis, but the low enzyme productivity and stability are still challenges. In the current study, Bacillus subtilis (coded ARSE2) revealed potent xylanase activity among other local isolates. The enzyme production optimization revealed that maximum enzyme production (490.58 U/mL) was achieved with 1\% xylan, 1.4\% peptone, and 5\% NaCl at 30 \& DEG;C and pH 9. Furthermore, several lignocellulosic wastes were exploited for sustainable xylanase production, where sugarcane bagasse (16\%) under solid-state fermentation and woody sawdust (2\%) under submerged fermentation supported the maximum enzyme titer of about 472.03 and 485.7 U/mL, respectively. The partially purified enzyme revealed two protein bands at 42 and 30 kDa. The partially purified enzyme revealed remarkable enzyme activity and stability at 50-60 \& DEG;C and pH 8-9. The enzyme also revealed significant stability toward tween-80, urea, DTT, and EDTA with V-max and K-m values of 1481.5 U/mL and 0.187 mM, respectively. Additionally, the purified xylanase was applied for xylooligosaccharides production, which revealed significant antimicrobial activity toward Staphylococcus aureus with lower activity against Escherichia coli. Hence, the locally isolated Bacillus subtilis ARSE2 could fulfill the xylanase production requirements in terms of economic production at a high titer with promising enzyme characteristics. Additionally, the resultant xylooligosaccharides revealed a promising antimicrobial potential, which paves the way for other medical applications.
Adsorbents derived from agro-waste can be a feasible substitute for the synthesis of the activated biochar for the removal of pollutants from their aqueous solution. ZnCl2 was used to activate the pyrolyzed biochar, derived from sugarcane bagasse. Physical characterizations of synthesized activated pyrolyzed biochar were analyzed by XRD, FTIR, and SEM. From the BET analysis, the surface area of activated pyrolyzed biochar was determined as 51.733 m(2)/g. Investigations on the adsorption of Malachite Green (MG) dye using activated biochar was studied in batch and fixed-bed system. Isotherm study suggested that the Freundlich isotherm model (R-2=0.9955) provided the best fit to the equilibrium adsorption and the biosorption capacity obtained as 90.1mg/g at 30 degrees C. Experimental data showed well in accordance with the pseudo-second-order kinetic model. The thermodynamic study indicated the spontaneous and exothermic nature of reactions involved. Boyd's film diffusion model was used with the kinetic data of the Batch adsorption experiment to evaluate the diffusion mechanism and ratelimiting step. The derived value of the average effective diffusion coefficient (D-e) was 0.014 x 10(-7) m(2)/s. The Yoon-Nelson and Thomas model ware well fitted with the experimental data obtained from column adsorption study. The dispersion coefficient and mean pore velocity for adsorbent columns were estimated using the breakthrough curves at various experimental conditions. Adsorption Kinetic parameters for MG dye were estimated using the solute transport model by combining convective flow and hydrodynamic dispersion with a two-site adsorption model and coupled with inverse modeling of breakthrough curves.
The use of toxic baits with spinosyns (spinosad and spinetoram), along with the parasitoid Diachasmimorpha longicaudata, is a sustainable alternative for the management of Ceratitis capitata. This study aimed to evaluate the lethal concentration (LC) and lethal time (LT) of spinosad and spinctoram, associated with the food lures sugarcane molasses at 7 \%, Biofruit at 3 \%, Ceratrap (R) at 1.5 \%, Flyral (R) at 1.25 \%, Isca Samarita (R) and Samarita Traditional (R) at 3 \%, on C. capitata, under laboratory conditions, as well as their effect, at the concentration of 96 mg L-1, on D. longicaudata. For the lethal time data, mortality was assessed at 2,4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 36, 48, 60, 72, 84 and 96 h after the exposure to the toxic baits. The lowest lethal concentrations (LC50 and LC95), to spinetoram (0.5 mg L-1 and 3.7 mg L-1 respectively) and spinosad (0.8 mg L-1 and 7.8 mg L-1, respectively), corresponded to the association with Samarita Traditional (R) at 3 \%. The lowest lethal time (TL50), in hours, for the spinosad insecticide, corresponded to the formulation containing Biofruit at 3 \%(6.6), and, to spinetoram, Samarita Traditional (R) at 3 \% (7.9). For D. longicaudata, the formulations that caused the lowest mortality corresponded to the association of Biofruit (R) at 3 \% with spinosad (4.7 \%) and Samarita Traditional (R) at 3 \% with espinetoram (3.5 \%). The toxic baits formulated with spinosad and espinetoram, associated with Isca Samarita (R) at 3 \%, caused a mortality rate of more than 60 \% to the parasitoid D. longicaudata.
Continuous and increasing demands for bioenergy have prompted the discovery of novel routes for effective bioconversion of lignocellulose into commodity chemicals. To this end, cellulolytic bacteria were isolated and screened from the gut system of oriental leafworm, Spodoptera litura. The plate-based screening revealed maximum cellulolytic activities by Bacillus pumilus SL8 displaying a clearance zone of 21 mm with a hydrolytic capacity of 10.5. When tested further, B. pumilus SL8 depicted the highest substrate degradation of corn cob powder (CCP, 59.2\%) followed by sawdust (SD, 54.2\%), and sugarcane bagasse (SCB, 52.6\%). Among the cellulolytic enzymes, maximum activities were achieved for xylanase, endoglucanase, and beta-glucosidase that corresponded to 50.5 +/- 5, 22.8 +/- 2.4, and 22.4 +/- 3 IUmg-1 protein, respectively on the wheat husk, CMC, and Avicel. The field emission scanning electron microscopy (FESEM) revealed adhesion of the bacteria to the substrate causing structural alterations due to hydrolysis. The hydrolysis of the substrate was further substantiated through FTIR analysis that depicted reduction in the intensity of cellulose representing bands such as 662, 895, 1184, 1371, and 1599 to 1749 cm-1 signifying degradation by B. pumilus SL8. Additionally, B. pumilus SL8 demonstrated its coculturing efficiency with the yeast strain for bioconversion of cellulose into bioethanol. The overall results suggest the potential utility of B. pumilus SL8 for biotechnological applications. (c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
White-rot basidiomycetes are the organisms that decompose lignin most efficiently, and Trametes villosa is a promising species for ligninolytic enzyme production. There are several publications on T. villosa applications for lignin degradation regarding the expression and secretion of laccase and manganese peroxidase (MnP) but no reports on the identification and characterization of lignin peroxidase (LiP), a relevant enzyme for the efficient breakdown of lignin. The object of this study was to identify and partially characterize, for the first time, gDNA, mRNA, and the corresponding lignin peroxidase (TvLiP) protein from T. villosa strain CCMB561 from the Brazilian semiarid region. The presence of ligninolytic enzymes produced by this strain grown in inducer media was qualitatively and quantitatively analyzed by spectrophotometry, qPCR, and dye fading using Remazol Brilliant Blue R. The spectrophotometric analysis showed that LiP activity was higher than that of MnP. The greatest LiP expression as measured by qPCR occurred on the 7(th) day, and the ABSA medium (agar, sugarcane bagasse, and ammonium sulfate) was the best that favored LiP expression. The amplification of the TvLiP gene median region covering approximately 50\% of the T. versicolor LPGIV gene (87\% identity); the presence of Trp199, Leu115, Asp193, Trp199, and Ala203 in the translated amplicon of the T. villosa mRNA; and the close phylogenetic relationship between TvLiP and T. versicolor LiP all indicate that the target enzyme is a lignin peroxidase. Therefore, T. villosa CCMB561 has great potential for use as a LiP, MnP, and Lac producer for industrial applications.
The application of biochar in agricultural practices and vegetative slopes has been rigorously recommended in previous literature. However, its potential application in other industries is scarcely explored. Biochar is a chemically stable material with a low thermal conductivity, which makes it a perfect fit for blending with soil to use as thermal backfills. A thermal backfill is an essential component for maintaining the ambient temperature around the underground pipelines and storage tanks of crude oil industries. This study investigates the potential application of eighteen soil-biochar blends as thermal backfill. Highly plastic silt and clayey sand (SC) soil were amended with three different biochar types viz. hardwood biochar, water hyacinth biochar, and sugarcane bagasse biochar (SBBC), at three biochar contents of 2.5\%, 5\%, 7.5\% (w/w). Thereafter, their compaction characteristics, thermal and physicochemical properties were investigated. The thermal conductivity (K) and volumetric heat capacity (C) of MH soil were reduced by 22\%, 29\%, 33\%, and 16\%, 24\%, 26\% with 7.5\% amendment of hardwood, water hyacinth, and SBBC. Similarly, K and C values of SC soil decreased by 22\%, 34\%, 37\%, and 12\%, 18\%, and 20\%. The micrographic analysis of soil-biochar blend reveals that the entrapped air in biochar particles governs the heat transfer in biochar-amended soil. An inverse correlation of thermal conductivity with pH and electrical conductivity was also observed for the soil-biochar mixes. This study extends the domain of biochar application highlighting the engineering properties of different blends, which would be helpful for its field-scale application. {[
Samarium (Sm) sorption from aqueous solutions was evaluated in biochars (derived from castor meal (CM), eucalyptus forest residues (CE), sugarcane bagasse (SB) and green pericarp of coconut (PC)) and in other carbon rich materials (coal fines (CF); two commercial activated charcoals (GAC, NGAC)) by applying batch and continuous-flow sorption experiments. Batch experiments revealed great Kd values, in the range of 10(4)-10(5) L kg(-1), and high Sm sorption percentages (>97\%, except for SB) in the range of environmental representative concentrations, using as-received materials, with no further treatments. Maximum sorption capacities were derived from sorption isotherms using the Langmuir model (from 1.2 to 37 mg g(-1)). Continuous-flow sorption experiments permitted to obtain maximum sorption capacities by mass balance and by fitting the experimental breakthrough curves to Thomas and Yan models. CF exhibited the greatest maximum sorption capacity (40 mg g(-1)) besting the commercial activated charcoals, while CM was established as the best biochar (7.2 mg g(-1)), with similar results to NGAC (12 mg g(-1)) but worse than GAC (36 mg g(-1)). The contribution of cation exchange in Sm sorption was confirmed to be significant for most materials based on the analyses of cations leached during continuous-flow sorption experiments. Maximum sorption capacities derived from Langmuir fitting correlated well with maximum sorption capacities obtained from continuous-flow experiments. Both methods were confirmed to be suitable to determine the maximum Sm sorption capacity of the materials and then to propose the most suitable materials that can act as alternative to commercial activated charcoals.
Background: The productivity of four strains of shiitake (Laminae edodes) on diverse lignocellulosic by-products used as substrates were evaluated. The objective was to determine the correlation between the composition of the substrate with the productivity of carpophores and their polyphenol content. The fungi were produced on vineyard prunings (VP), sorghum stubble (SS), sugarcane bagasse (SB), and oak shavings (OS). The productivity was evaluated based on the biological efficiency (BE), production rate (PR), and yield (Y). To evaluate the effect on shiitake growth on the chemical composition of the substrates, the content of fiber (neutral detergent fiber (NDF), hemicellulose, cellulose, lignin] was determined before and after inoculation. Total phenolic compounds were quantified by spectrophotometry. Results: The highest BE was observed for the IE-256 strain on SS (145.11\%), and the highest PR for the IE-245 strain on SS (1.69\%). The highest Y was observed for the IE-256 strain on SS (41.96\%). The fiber results were significantly affected by growth period, strain, substrate, and the selected combinations of strains and substrates. The phenolic compound content of the carpophores was also significantly affected by substrate and strain; the lowest and highest values were obtained for the IE-256 strain on OS (1.5983 mg GAE.g-1) and SS (2.7197 mg GAE.g-1), respectively. Conclusions: On average, the highest carpophores production per substrate and strain corresponded to SS and IE-245, respectively. The carpophores of the IE-256 strain cultivated on SS could potentially present greater antioxidant activity because of their high polyphenol content.
Biodegradable plastic composites were produced from mixtures of polyvinyl alcohol (PVA) and starch, which were mixed with different natural fillers {[
Bioresource based blends exploit the synergy between polymers derived from renewable resource and commercial polymers to obtain desirable physical, mechanical, and biodegradable properties. With the aim to develop a sustainable resource based biodegradable mulch films, nanostructured blends of epoxies of linseed oil (LOE) and dehydrated castor oil (DCOE) with poly (vinyl alcohol) (PVA) were prepared in the weight ratios of 20/80, 50/50 and 80/20. Microwave-assisted blending was used for the synthesis of DCOE/LOE blends with PVA and the results were compared with conventional solution blending using FT-IR, TGA-DTA and optical measurements. The results revealed that microwave-assisted blending proved to be an efficient method for the formation of compatible blends in a short span of time as compared to conventional solution blending. Transmission electron microscopy (TEM) analysis of DCOE/PVA and LOE/PVA blends synthesized by microwave-assisted method confirmed the formation of a nanostructured blend. Scanning electron microscopy (SEM), respirometry and mechanical measurements were carried out to compare the morphology, biodegradability, and the mechanical strength of DCOE/PVA and LOE/PVA blends. It was observed that DCOE/PVA blends exhibited higher biodegradability, better mechanical properties, and lower moisture absorption characteristics as compared to LOE/PVA blends. The mechanical strength, moisture absorption, and biodegradability of these blends were also compared with blends of other bioresource based polymers such as sugarcane bagasse (SCB), waste gelation (WG), apple peal (AP), and starch/glycerol with PVA, as available from the cited literature in the text. (C) 2010 Elsevier Ltd. All rights reserved.
Lignocellulosic biomass can play a pivotal role in achieving the goal of sustainable development of a predominantly agrarian country like India. The abundant availability of lignocellulosic materials makes it more suitable to go for the energization of this waste material. Lignocellulosic agriculture waste is essentially renewable and carbon-neutral source of energy. It has the potential to minimize greenhouse gas emissions by adopting proper biomass to energy conversion routes like biochemical conversion to mitigate climate change. Pretreatment of lignocellulosic biomass is a compulsory step for delignification before hydrolysis and subsequent AD or fermentation process to facilitate enhanced biofuel (biogas/bioethanol) generation. The most studied pretreatment methods of lignocellulosic agricultural biomass in the past 10 years including acid, alkali, ionic liquid, microwave, ultrasonication, steam explosion, liquid hot water, ammonia-based, biological, and electrohydrolysis pretreatments methods are discussed in this review paper. The criteria to measure pretreatment efficiency, different pretreatment processes parameters, and their pros and cons are also discussed. The alkaline pretreatment method is most promising in the delignification of lignocellulosic agricultural biomass residues like rice straw. This review may impart help to the prospective researchers in understanding rubrics of different pretreatment processes for further research work in the area of pretreatment.
Nowadays when conventional plastic is being looked as a menace, the possibility of it being replaced with polyhydroxyalkanoates (PHAs) which are biodegradable, environment friendly and biocompatible thermoplastics is not remote. PHAs are a fascinating group of biopolyesters stored within the cytoplasm of numerous bacterial cells as energy and carbon reserves. PHAs signify the best promising biological substitute to certain conventional petrochemical plastics which have wide range of applications in different industries such as biomedical sector, packaging, toners for printing, and adhesives for coating, etc. In the present study, PHAs producing bacterial strains were screened by Sudan black B staining and confirmed by Nile blue A staining. Out of forty bacterial strains showing positive results, six bacterial strains exhibited comparatively higher PHAs production. The highest PHAs producing bacterial strain was identified using 16s rRNA sequencing. Optimization of process parameters was performed by using one factor at a time (OFAT) approach. The isolated bacterium was able to synthesize PHAs when various agro-industrial wastes such as domestic kitchen waste, mixed fruit pulp, sugarcane molasses, and waste flour from bread factory were screened as a carbon substrate in the growth medium. The results showed accumulation of 44.5\% PHAs of cell dry weight using domestic kitchen waste as carbon substrate. The characterization of biopolymers was performed using FTIR and XRD analysis. The commercial exploitation of results of this study may serve twin purposes of addressing the challenge of high production cost of PHAs being the major constraint in replacing petro-based plastics as well as address the problem of disposal of recurring domestic kitchen waste and other agro-industrial waste.
The potential of 1-buthyl-3-methylpyridinium chloride, {[
In the past decade, algal waste has been used as useful natural resource for production of enormous range of products that have wide economical and commercial importance. Pectinases are group of enzymes that have wide commercial applications. Hence, current study was designed to utilize algal biomass for the production of pectinases using submerged (SmF) and solid state fermentation (SSF) techniques. Different algal sources including brown (Dictyopteris polypodioides, Sargassum wightii and Dictyopteris divaricata) and green algae (Ulva lactuca and Codium tomentosum) were used and U. lactuca was found to be the most suitable substrate. Several bacterial and fungal strains were screened and among them Bacillus licheniformis KIBGE-IB4 was selected based on maximum pectinase production. SmF and SSF were studied utilizing U. lactuca as a substrate and results revealed that enzyme production was favoured by SmF (2457 +/- 3.31 Umg(-1)) as compared to SSF (1432 +/- 1.46 Umg(-1)). Parametric optimization of pectinase production indicated that B. licheniformis KIBGE-IB4 requires 10.0 g L-1 U. lactuca as a biomass in the medium with a pH 7.0 when incubated at 37 degrees C for 24 hours. Likewise, production of pectinase using algal resource was also compared with that of the conventional agricultural biomass and it was observed that when U. lactuca was used, the selected bacterial isolate produced a higher yield of enzyme than sugarcane bagasse and rice husk. Hence, it is anticipated that algal biomass can be efficiently utilized as an environmental friendly bioresource for the production of industrially important hydrolytic enzymes.
The enhanced significant use of electromagnetic wave introduces new type of pollution in the environment called Electromagnetic Interference (EMI). Different shielding techniques though successfully works in the present scenario but small efficiency of attenuation and absorption capacity of traditional ceramics demands some alternative potential material for enhanced shielding efficiency, which can be realised from agricultural waste such as rice husk, sugarcane bagasse, etc. Further, the shielding structure and composition of composite are the current issues which depend on the dielectric properties of the fabricated materials. In the current work, rice husk, an organic biomaterial rich in carbon, is combined with epoxy to create a microwave absorber that is flexible, inexpensive, and eco-friendly. The different microwave absorbing property such as complex dielectric, tangent loss, attenuation constant and Reflection Loss (RL) of -14.5 dB at frequency 10 GHz are found to be possessed by the synthesized composite of thickness 3 mm which is determined from composite's dielectric values. The attenuation coefficient supports the measured values of RL, highlighting the significance of the suggested composite material with a power attenuation efficiency of around 87\% for legitimate microwave absorption applications. The presence of good percentage of elemental combination like carbon, oxygen and silicon makes it possible for increasing the percentage of activated carbon which is not present in any other synthetic component for the same purpose. Further use of carbon rich waste material is an advantageous impetus for material industries to enhance the percentage of activated carbon for shielding purpose.
Spreader Stoker thermal power plants are initially used to burn bagasse during the sugarcane harvest, but also coal when the season is over. The drawback is that, compared to standard pulverized coal fly ashes, the coal fly ashes resulting from this process contain many more unburned particles. Therefore, Spreader Stoker Coal Fly Ash (SSCFA) is sent to landfill despite its potential for valorisation in construction. The main objective of this work was to evaluate the potential of laboratory manufactured composite cements incorporating SSCFA by using a variety of manufacturing methods, such as co-grinding/separate grinding of the components, and grinding of laboratory cements to equivalent global fineness. The behaviour in the fresh, hardening and hardened states was investigated to bring out the influence of Blaine specific surface and type of addition in different combinations of composite cements. Despite the high carbon content of the coal fly ash studied, the mechanical behaviour of SSCFA-cements was better than that of cement with the local pozzolan, which is the reference in Reunion Island. In addition, the use of slag and the pozzolan/SSCFA association in composite cements showed good results. An artificial neural network approach was employed to predict compressive strength in mortars with parameters such as amounts of clinker, gypsum, pozzolana, SSCFA and slag, and the Blaine specific surface. The results also enabled compressive strength response curves to be developed for mixes according to the amount of clinker in the cements. (c) 2021 Elsevier Ltd. All rights reserved.
Phosphate fixation is a main factor limiting phosphate availability and reducing crop production in acidic soils. Although biochar addition has been suggested as a means of ameliorating acidic soils, questions remain about the impacts of biochar on phosphate fixation and availability in these soils. To address these questions, a biochar produced from sugarcane bagasse was added at four different levels (0, 1, 3, and 6\% w/w) to an acidic soil. After 30 days of incubation, comparisons were made between the chemical properties of the biochar-amended soils and those of the original one. Sorption isotherm experiments were also conducted to estimate soil phosphate sorption capacity and affinity parameters under biochar amendment. Results showed that biochar application improved such soil chemical properties as pH and cation exchange capacity as well as exchangeable calcium, magnesium, sodium, and potassium cations. Biochar was also observed to increase phosphate sorption capacity of the soil but reduce its phosphate sorption strength, indicating that biochar-amended soils were potentially able to fix lower amounts of phosphate than the original acidic soil was. Moreover, soil phosphate buffering capacity indices decreased as a result of biochar incorporation, indicating the easier release of phosphate from the solid to the solution phase in biochar-amended soils. Biochar addition was also observed to reduce effectively (up to 62\%) the standard phosphorus requirement of the soil. In conclusion, biochar amendment was found to induce positive changes in phosphate sorption properties of acidic soils, thereby providing conditions more favorable to plant growth through sufficient phosphate availability.
The main purpose of the present study was to evaluate the effect of an initial aeration rate on the sporulation of six Trichoderma strains under solid state fermentation conditions and to evaluate the behavior of the lytic enzymes involved in the process at laboratory scale. A mixture of sugarcane bagasse, wheat bran, chitin, potato flour and olive oil were used as a substrate. Cultures were carried out using glass columns applying an initial aeration rate of 50 ml min(-1) (2 mL min(-1)g(-1)). Under the present culture conditions, chitinase and amylase activities were enhanced by the aeration with values of 30.74 and 44.54 U g(-1) with T. longibranchiatum. These vales represent an increase of 226 and 167\%, respectively compared with the system without air supply. For most of the strains, the forced aeration increased the endoglucanase activity, but the best value was observed with T. yunnanense (38.32 U g(-1)). All strains showed low values of exoglucanase and lipase when the aeration was applied. Trichoderma spp. was the strain most affected negatively by the aerated process, showing the lowest enzyme activities. The forced air supply into solid-state fermentation did not improve the production of spores from Trichoderma since similar results were obtained in the process without forced aeration. On this report, we reach concentrations greater than 1 x 10(9) spores per gram of substrate at 96-120 h of culture, indicating a feasible approach of agro-industrial wastes as a substrate for the biomass production.
Caulobacter crescentus is able to express several enzymes involved in the utilization of lignocellulosic biomasses. Five genes, xynB1-5, that encode beta-xylosidases are present in the genome of this bacterium. In this study, the xynB2 gene, which encodes beta-xylosidase II (CCNA\_02442), was cloned under the control of the PxylX promoter to generate the O-xynB2 strain, which overexpresses the enzyme in the presence of xylose. In addition, a null mutant strain, Delta-xynB2, was created by two homologous recombination events where the chromosomal xynB2 gene was replaced by a copy that was disrupted by the spectinomycin-resistant cassette. We demonstrated that C. crescentus cells lacking beta-xylosidase II upregulates the xynB genes inducing beta-xylosidase activity. Transcriptional analysis revealed that xynB1 (RT-PCR analysis) and xynB2 (lacZ transcription fusion) gene expression was induced in the Delta-xynB2 cells, and high beta-xylosidase activity was observed in the presence of different agro-industrial residues in the null mutant strain, a characteristic that can be explored and applied in biotechnological processes. In contrast, overexpression of the xynB2 gene caused downregulation of the expression and activity of the beta-xylosidase. For example, the beta-xylosidase activity that was obtained in the presence of sugarcane bagasse was 7-fold and 16-fold higher than the activity measured in the C. crescentus parental and O-xynB2 cells, respectively. Our results suggest that beta-xylosidase II may have a role in controlling the expression of the xynB1 and xynB2 genes in C. crescentus.
Many attempts were reported to optimise variables in xanthan gum fermentations, i.e. the nutrient composition and feeding technique, temperature, pH, agitation, and adding antifoam. All shows some improvement in the area studied. Other substrates were also tested, such as hydrolysed rice, barley and corn flour, acid whey and sugarcane molasses, etc., but glucose is still the best in-term of the product yield, supply, and the product quality. Sufficient studies of the unstructured kinetics and the structured kinetics models were described in batch processes but the continuous kinetic model is insufficiently cared. Looking at the conventional xanthan production, mixing is the main problem occurred in batch fermentation as the produced broth during the production stage is very viscous, therefore mixing requires considerable balance between cell disruptions and oxygen transfer. Giving the support, e.g. cotton wool and fabric, for microorganisms to adsorb may ensure the nature physical separation between microorganisms and the liquid phase containing nutrients and products. However, the specific xanthan productivity was reported low due to relatively low cell viability. The problem of the limited oxygen transfer suggests that a new bioreactor design is required. The design strategy could be by freely moving of the liquid media and air passing through the porous fibrous matrix, therefore should ensure a good contact between cells that adsorb onto the fibrous matrix support and nutrients. This strategy should improve oxygen transfer, and may increase the reaction rate and reduce the fast growing of mutation. Using ultrafiltration was reported save up to 80\% of the energy is required for recovering of xanthan gum. (c) 2006 Elsevier Inc. All rights reserved.
The upgrade of wet biomass sources into char presents a big challenge and is deemed as a non-feasible process in many cases using the conventional thermal carbonization. Hydrothermal carbonization (HTC) and vapothermal carbonization (VTC) are promising techniques for wet biomass carbonization since no pre-drying is required. Two types of wet biomass waste materials were investigated, bagasse (BG) and lime peel (LP), with moisture content of 67\% and 78\%, respectively. Experimental test rig was developed to study the effects of HTC and VTC processes on the raw materials in terms of product properties and combustion characteristics. For HTC process, water-to-biomass (W/B) ratio showed a significant effect on the product heating value with 10.2\% difference for BG and 6.6\% for LP through the W/B tested range. On the other hand, VTC process provided a significantly higher elevation in heating value up to 33\% and 32\% for BG and LP, respectively, compared to 20\% and 16\% for the HTC process.
The application of methodologies for the optimal design of integrated processes has seen increased interest in literature. This article builds on previous works and applies a systematic methodology to an integrated first and second generation ethanol production plant with power cogeneration. The methodology breaks into process simulation, heat integration, thermo-economic evaluation, exergy efficiency vs. capital costs, multi-variable, evolutionary optimization, and process selection via profitability maximization. Optimization generated Pareto solutions with exergy efficiency ranging between 39.2\% and 44.4\% and capital costs from 210 M\$ to 390 M\$. The Net Present Value was positive for only two scenarios and for low efficiency, low hydrolysis points. The minimum cellulosic ethanol selling price was sought to obtain a maximum NPV of zero for high efficiency, high hydrolysis alternatives. The obtained optimal configuration presented maximum exergy efficiency, hydrolyzed bagasse fraction, capital costs and ethanol production rate, and minimum cooling water consumption and power production rate. (C) 2016 Elsevier Ltd. All rights reserved.
The aim of this work was to study the effects of pretreatment process, hydrolysis condition and structural features of lignin on the improving action of surfactants (Tween 20) for enzymatic hydrolysis of pretreated wheat straw, and further to interpret the relation of these factors with the non-productive adsorption of cellulases on lignin. Tween 20 seemed to be more greatly improve cellulose conversion under harsher conditions. The surfactant showed more significant improvement for acid-pretreated substrates than oxidative-pretreated substrates. Highly-condensed lignin and phenolic hydroxyl groups showed much stronger adsorption ability to cellulases, while Tween 20 could well block the lignin-cellulase interactions recovering cellulose hydrolyzability. It was proposed that pretreatments altered lignin structures, resulting in the change of surface properties thus further impacting the lignin-cellulase interactions. Addition of Tween 20 could modify lignin surface properties to change its hydrophobicity, hydrogen bonding ability and surface charges, thus reducing the nonproductive adsorption of proteins.
Asphalt pavement recycling has become a common practice across the globe and has been successfully employed in construction of new pavements. While several studies considered utilization of reclaimed asphalt pavement (RAP) aggregates for flexible and rigid pavements, very few attempted its possibility for roller compacted concrete pavements (RCCP). Additionally, studies on the possibility of enhancing the proportion of RAP for RCCP are very scanty. The present study is an attempt to increase the potential of RCCP mixes containing 50\% RAP (dust contaminated \& stiffened asphalt coated: SCRAP via including various industrial and agricultural wastes such as Silica Fume, Fly ash, and Sugarcane ash as partial replacement of conventional cement. It was observed that the inclusion of the stated admixtures had an insignificant effect on the density of the fresh RCCP mixes, however, increased the moisture demand considerably. In fact, the results firmly indicated the potential of silica fume for RAP-RCCP blends, as, it not only enhanced the physical and mechanical properties, but found to improve the durability of RCCP mixes considerably. Also, utilization of silica fume was found to be economical \& environmentally friendly amongst all wastes: with reduced initial construction cost \& CO2 emissions by up to 8.4\% \& 9.7\%. As far as the other industrial wastes are concerned, 15\% fly ash could also be utilized for producing sustainable RCCP mixes, whereas, higher dosage of fly ash (30\%) and sugarcane ash (10 \& 15\%) may be employed as base layer material of conventional concrete pavements.
Novel approach to develop a biomass derived lignin-cellulose based, ultra-light, hydrophobic graphene supported spongy composite was synthesized to absorb oil and organic solvents from wastewater. Spongy composite was synthesized by a facile and highly efficient one-pot hydrothermal method from the natural precursor. Lignin-cellulose functionalized graphene (LCG) sponge was synthesized from graphene oxide (GO) and sugarcane waste powder (SCwP) in presence of natural latex. LCG successfully demonstrated separation of oil from oil-water mixture. LCG has high oil sorption capacity in the range of 25-50 g of oil per gram of sorbent. This material showed high efficiency as a sorbent to separate organic chemicals from wastewater. The absorption capacity of LCG sponge was enhanced thrice in comparison with SCwP and could be reused up to 10 cycles. The continuous oil water separation process was demonstrated using LCG sponge from the oil-water mixture, which can be applied for large scale oil recovery from the waste stream.
The adoption of complete package of practices on farmer's fields gave higher economic return rather than when practices were adopted partially. The yield of green legume fodder berseem cv. vardan was compared on farmer's field with the yield of unidentified varieties.. The performance of berseem cv. Vardan showed better results as compared to the unidentified varieties sown under field conditions. The data were recorded from all the selected farmers and compared the same with of green fodder. The knowledge of farmers regarding growing of high yielding variety of berseem fodder two crops was measured and it was observed that majority of the farmers (66\%) were in the category of medium knowledge level. Maximum fodder requirement through out the year was fulfilled from the sugarcane and other crops such as wheat and paddy straw etc. So, only limited area in the selected village Lalukheri was put under fodder crops cultivation. All the selected farmers perceived that fodder yields of Vardan Berseem were high as compared to unidentified varieties grown on their fields. Knowledge level was positively and significantly correlated with variables such as education (0.778), family education status (0.526), income (0.387) and extension contact (0.566). The other variables such as age, caste, size of holding, and social status were not significantly correlated.
The aim of the study was to determine tolerance of plant growth promoting rhizobacteria (PGPR) in different concentrations of Cu, Cr, Co, Cd, Ni, Mn, and Pb and to evaluate the PGPR-modulated bioavailability of different heavy metals in the rhizosphere soil and wheat tissues, grown in saline sodic soil. Bacillus cereus and Pseudomonas moraviensis were isolated from Cenchrus ciliaris L. growing in the Khewra salt range. Seven-day-old cultures of PGPR were applied on wheat as single inoculum, co-inoculation and carrier-based biofertilizer (using maize straw and sugarcane husk as carrier). At 100ppm of Cr and Cu, the survival rates of rhizobacteria were decreased by 40\%. Single inoculation of PGPR decreased 50\% of Co, Ni, Cr and Mn concentrations in the rhizosphere soil. Co-inoculation of PGPR and biofertilizer treatment further augmented the decreases by 15\% in Co, Ni, Cr and Mn over single inoculation except Pb and Co where decreases were 40\% and 77\%, respectively. The maximum decrease in biological concentration factor (BCF) was observed for Cd, Co, Cr, and Mn. P. moraviensis inoculation decreases the biological accumulation coefficient (BAC) as well as translocation factor (TF) for Cd, Cr, Cu Mn, and Ni. The PGPR inoculation minimized the deleterious effects of heavy metals, and the addition of carriers further assisted the PGPR.
Organosolv pretreatment is highly effective for delignification of lignocellulosic materials (LCMs), but the requirement for high operation temperature has economically hindered the industrial use of this process. Although it is accepted that organosolv pretreatment using thermo energy can have a high delignification effectiveness, the effect of using electric energy as an alternative to thermal energy has not been investigated. In this study, we have investigated different solvents and applied potentials to refine the electro-assisted organosolv pretreatment (EAOP) process, aiming at the delignification of LCMs at ambient temperature. The solvents used for EAOP are referred to as ionic liquid-promoted organic solvent (IL/O), which consisted of an ionic liquid (IL) and an organic solvent (O), with combinations of three ILs and four organic solvents. Selected physicochemical and electrochemical properties of these IL/O were initially characterized to identify the promising solvent compositions, such as those that support OH{*
Novel hydrophobic hemicelluloses possessing hydrophobic groups were prepared by the benzylation of wheat straw hemicelluloses with benzyl chloride under the presence of catalyst in an ethanol/water system. In particular, the progress of the benzylation reaction was studied as a function of the volume ratio of ethanol/water from 4:1 to 6:4, the molar ratio of NaOH/anhydroxylose unit in hemicelluloses from 0.6:1 to 1.5:1, the molar ratio of benzyl chloride/anhydroxylose unit in hemicelluloses from 0.5:1 to 2.0:1, reaction temperature 50-80 degrees C, and reaction time 4-20h. Benzylated hemicelluloses with the low degree of substitution from 0.09 to 0.35 were obtained depending on the experimental conditions. The incorporation of benzyl groups into the backbone of hemicelluloses was confirmed by FT-IR and C-13 NMR spectroscopies. The thermal stability increased after the modification of hemicelluloses due to the introduction of benzyl groups. The introduction of benzyl groups endows hemicelluloses with the hydrophobicity, which could be potentially applied in plastic industries. (C) 2012 Elsevier Ltd. All rights reserved.
Wheat straw hemicelluloses were converted to novel bifunctional hemicellulosic derivatives by etherification using acrylamide as reactant and sodium hydroxide as catalyst, The degree of substitution can be monitored by altering the molar ratio of acrylamide to xylose unit in hemicelluloses in the range of 1.0-10.0 and the molar ratio of sodium hydroxide to xylose unit in hemicelluloses in the range of 0.5-1.6, without changing the structure of the hemicelluloses. Comparison of the reaction in different media is discussed in detail. The optimized product with a high DS value of 0.58 was obtained by varying the condition parameters. Novel hemicellulosic derivatives containing carbamoylethyl and carboxyethyl groups could be confirmed by FF-IR, H-1 NMR, and C-13 NMR spectroscopies. The behavior of hemicellulosic derivatives was monitored by means of thermogravimetry (TG) and differential thermal analysis (TGA). It was found that the product with a high DS had a lower thermal stability than the native hemicelluloses.
Availability of feeds and fodder and amount of their intake by large ruminants in eight different agro-ecological zones (AEZ) of Bangladesh were recorded over a year. Roughages such as straw, naturally grown green grass, water hyacinth, tree leaves, legumes and sugarcane tops were the major feedstuffs fed to the large ruminants. Amount of intake of these ingredients differed (p<0.01) across AEZ studied, but did not differ across seasons or farmers' categories (p>0.05) except for green grasses (p<0.01). Byproduct concentrates offered to animals in the studied areas were rice bran, wheat bran and different oil cakes. The amount of intake of concentrates by the animals also differed (p<0.01) across AEZs, but did not differ across seasons or farmers' categories (p>0.05), except for rice bran and wheat bran which differed between season and farm category, and season respectively (p<0.01). The large standard errors of mean indicate that there are wide variations in intake of roughages and concentrates across AEZ's, seasons and farmers' categories and even across days. This further indicates that the feeding practices of large ruminants are largely heterogeneous. In addition to feeding roughage and concentrates, the animals were allowed to graze for six hours a day. Grazing hours also differed (p<0.01) across AEZ, but not by farmers' categories or seasons.
HMF (hydroxymethylfurfural), a compound that occurs naturally in food, is derived from the dehydration of monosaccharides (glucose and fructose) in products subjected to high-temperature treatments or to aging processes. HMF can be obtained by acid-catalyzed dehydration of lignocellulosic biomasses such as sugarcane bagasse and other agricultural residues. In this work, analytical quantification of HMF and furfural (the main co-product) was performed using high-performance liquid chromatography coupled with diode array detection (HPLC-DAD). The official method employs isocratic elution with a mobile phase composed of water and acetonitrile at a ratio of 80:20 (v/v). The analytical method proposed here was developed using 2,5-furandicarboxylic acid (FDCA) as internal standard, for the first time, with 0.01 mol L-1 trisodium citrate and ultrapure water as the mobile phase, adjusted to pH 2.5. The acidity of the mobile phase was required to avoid FDCA deprotonation. Good peak resolution and selectivity were obtained, without differences in the retention times of the analytes present in the standard solutions used to obtain the analytical curve and in the aqueous and organic phases from the synthesis of HMF using lignocellulosic biomass hydrolysis. The method complies with the current recommendations of AOAC regarding validation parameters. center dot The proposed HPLC method improves peak selectivity and resolution. center dot The method is suitable for acid sample media, such as aqueous and organic hydrolysis phases. center dot 2,5-Furandicarboxylic acid (FDCA) was used as internal standard. (c) 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)
This paper explores the viability of producing energy and agricultural soil conditioners with biochars and bio-oils from the pyrolysis of biomasses that in some cases are potential environmental pollutants. This approach addresses the need to develop sustainable production systems that minimize pollution and soil degradation, and meet the demand for renewable fuels. Large volumes of biomass from different sources are available in Brazil, including Eucalyptus crop residues (CE), castor meal (CM), coconut pericarp (CP), sugarcane bagasse (SB), and water hyacinth (WH). CM char and SB bio-oil are good prospects for energy generation. Characterization using DRIFT, C-13 NMR, and van Krevelen diagrams indicated that after carbonization, aromatic structures were predominant in the biochars produced from the CP, CE, and SB biomasses, while aliphatic groups were abundant in the biochars from CM and WH. Analysis using EPR showed that unpaired electrons were preferentially located on carbon atoms in the case of the CP, CE, and SB biochars, with EPR g values around 2.0030, while the CM and WH biochars presented g values around 2.0035, indicating that the unpaired electrons were closer to oxygen atoms. In terms of bio-oil chemical composition, the most abundant compounds were 3-pyridinol and furans (WH), phenols (CP), and hexadecanoic, octadecanoic, 9,12-octadecenoic (z,z),3-docosenoic, and 5-docosenoic acids (present only in the CM bio-oil). The bio-oils from SB and CE were quite similar and the main compound was 1,2,6-hexanetriol. The biomass sources studied produced reasonable amounts of bio-oil, and could compete as suitable raw materials for biofuel production. (C) 2015 Elsevier B.V. All rights reserved.
The present study has dealt with characterization and co-pyrolysis of binary and ternary blends of three biomass, viz. water hyacinth (WH), Thevetia peruviana (TP) and sugarcane bagasse (SCB). The biomass blends were characterized for proximate and ultimate analysis, surface morphology and functional groups. Co-pyrolysis of blends was carried out using a thermogravimetric analyzer (TGA) at heating rates of 8, 10, 15 and 30 degrees C min(-1). TGA data was analysed using Ozawa-Flynn-Wall (OFW), advanced isoconversional model of Vyazovkin (Vyazovkin \_AIC) and distributed activation energy model (DAEM). The dominant reaction mechanism of co-pyrolysis at different stages of conversions was deduced using Criado plots. The kinetic parameters of activation energy and pre-exponential factor, and thermodynamic parameters of Delta H and Delta S showed large variation with conversion, which is indicative of complex chemistry of thermal conversion of various structural components of biomass with synergistic interactions. The activation energies for binary blends WH SCB, WH TP, TP SCB were in the range 122.90-237.53, 127.93-272.92, and 124.80-235.94 kJ mol(-1), respectively. For ternary blends WH 111, WH 211 and WH 311, activation energy varied in the range 119.64-194.31, 123.40-246.80, and 121.65-194.75 kJ mol(-1), respectively. The predominant reaction mechanism for all blends was ordered reaction (F1) in lower conversion range (alpha <= 0.25), and diffusion limited process (D1 or D2 or D3) in higher conversion range (alpha = 0.35-0.55). Positive Delta H for all blends indicated endothermic nature, while positive Delta S indicated more disordered system after reaction - typical of pyrolysis.
Sorptive potential of selected agricultural waste materials i.e. rice (Oryza sativa) bran (RB), bagasse fly ash (BFA) of sugarcane (Saccharum officinarum), Moringa oleifera pods (MOP) and rice husk (RH) for the removal of methyl parathion pesticide (MP) from surface and ground waters has been investigated. Optimization of operating parameters of sorption process, i.e. sorbent dose, agitation time, pH, initial concentration of sorbate, and temperature have been studied. The sorption data fitted to Freundlich, Langmuir and Dubinin-Radushkevich (D-R) sorption isotherms. The maximum capacities of RB, BFA, MOP and RH for MP were calculated to be 3.6 +/- 0.8, 5.3 +/- 1.4, 5.2 +/- 1.5 and 4.7 +/- 1.0 mmol g(-1) by Freundlich, 0.39 +/- 0.009, 0.39 +/- 0.005 , 0.36 +/- 0.004 and 0.35 +/- 0.008 mmol g-1 by Langmuir and 0.9 +/- 0.08, 1.0 +/- 0.10, 1.0 +/- 0.10 and 0.9 +/- 0.07 mmol g(-1) by D-R isotherms respectively, employing 0.1 g of each sorbent, at pH 6, 90 min agitation time and at 303 K. Application of first order Lagergren and Morris-Weber equations to the kinetic data yielded correlation coefficients, close to unity. Thermodynamic parameters of sorption process, i.e. Delta H, Delta S and Delta G were computed and their negative values indicated the exothermic and spontaneous nature of sorption process. The pesticide may be stripped by sonication with methanol, making the regeneration and reutilization of sorbents promising. The sorbents investigated exhibited their potential applications in water decontamination, treatment of industrial and agricultural waste waters. (c) 2006 Elsevier Ltd. All rights reserved.
The function of engineered thermal backfills surrounding underground pipelines of the crude oil industry is to prohibit heat migration for the design period of 25 to 50 years. Biochar is suitable for reconstituting standard thermal backfill material since it is biochemically inert and has a low heat conductivity. However, the preparation of biochar from bio-mass involves an energy-intensive pyrolysis process. This study aims to make biochar production energy-efficient via optimizing the pyrolysis temperatures, specifically for thermal backfill applications. Ten distinct biochars were pre-pared by pyrolyzing two waste biomass, i.e., water hyacinth (WH) and sugarcane bagasse (SB), at temperatures rang -ing from 300 to 700 degrees C. The biochars were assessed based on their thermal conductivity, energy consumption, yield, and stability in soil for the design period. The thermal conductivity of produced biochars varied in a narrow range of 0.10 to 0.13 W m(-1 )K(-1) with different pyrolysis temperatures, which is possibly due to marginal differences in their microstructure, mineralogy, and physicochemical properties. The findings revealed that the biochar produced at lowest pyrolysis temperature (300 degrees C) consumed least energy and produced maximum yield. However, it was not suitable for thermal backfill applications due to its inadequate carbon stability in soil. Therefore, the current study rec-ommends a pyrolysis temperature of 400 degrees C for thermal backfill applications. The recommended pyrolysis temperature was found to be at least 60\% energy efficient in comparison to pyrolysis at 700 degrees C for both the feedstocks. This study provides crucial insight into the role of pyrolysis temperature for tailoring biochar production for intended applications.
The biological pretreatment of lignocellulosic biomass is a low-cost and eco-friendly method for facilitating enzymatic hydrolysis. In this study, strains with lignin depletion capability were screened using a high-throughput screening method. Sixty-three strains were screened out and Myrothecium verrucaria secreted three lignin-degrading enzymes simultaneously during the bio-pretreatment process. The activity levels of laccase, lignin peroxidase and manganese peroxidase were 6.61, 0.78 and 1.31 U g(-1) dry biomass. The content of lignin in corn stover decreased by 42.30\% after biopretreatment, and the conversion rate increased by 123.84\% during the subsequent saccharification process in comparison with the untreated corn stover. Furthermore, the effects of bio-pretreatment on the structure of corn stover were presented using a scanning electron microscope (SEM), Brunauer-Emmet-Teller (BET), X-ray diffractometer (XRD) and Fourier transform infrared spectroscopy (FTIR). The results showed that M. V. is a promising lignin-degrading fungus. This research demonstrated an efficient pretreatment approach for enhancing the enzymatic saccharification of corn stover.
Currently, there are a lot of discussions on the production of sustainable cement for construction purposes, unlike the conventional ordinary Portland cement (OPC), as its production, transportation, and application contribute to the generation of greenhouse gases, hence, climate change. Consequently, limestone, the primary material used to produce OPC, is non-renewable. Therefore, there is a need to use sustainable materials to make cementitious materials to achieve sustainable construction. This has led to a lot of research focussing on the valorisation of agricultural wastes and less economical, no-food lignocellulosic plants in producing sustainable and environmentally friendly cementitious materials commonly known as Supplementary Cementitious Materials (SCMs). The agrowastes ashes include rice husk ash (RHA), sugarcane bagasse ash (SCBA), and corn cob ash (CCA), among others. In contrast, the lignocellulosic plants' ashes include common water reed ash (CWRA) and cyperus papyrus ash (CPA). There has been the belief that these pozzolanic materials are homogenous. However, these ashes are highly heterogeneous when they undergo microscopic analysis. Therefore, the current data paper provides Laser Diffraction Spectroscopy (LD) for Particle Size Distribution (PSD), Fourier-transform infrared spectroscopy (FT-IR), X-Ray Fluorescence (XRF), and Scanning Electron Microscope (SEM) data for unprocessed CWRA and CPA in the form of tables, micrographs, and figures for microscopic analysis. This data helps characterise and evaluate CWRA and CPA's potential as pozzolanic materials, especially as road construction materials, and will be beneficial for other scientists to better understand unprocessed CWRA and CPA mineral information development biologically inspired materials for biologically inspired materials sustainable development across many disciplines. (C) 2022 The Author(s). Published by Elsevier Inc.
Huperzine-A (HupA) is an emerging, powerful, and promising natural acetylcholinesterase inhibitor. Despite that, the achieved yields of HupA from microbial sources are still far from the industrial applications. Accordingly, this paper was conducted to valorize solid-state fermentation (SSF) as an efficient production platform of HupA. Four agro-industrial wastes, namely rice bran, potato peel, sugarcane bagasse, and wheat bran, were tested and screened as cultural substrates for the production of HupA by the endophytic Alternaria brassica under SSF. Maximum HupA production was attained on using rice bran moistened by Czapex's dox mineral broth. In the effort to increase the HupA titer, supplementation of the best moistening agent by different carbon and nitrogen sources was successfully investigated. Additionally, factors affecting HupA production under SSF including substrate concentration, moistening level, and inoculum concentration were optimized using response surface methodology. A Box-Behnken design was applied for generating a predictive model of the interactions between these factors. Under the optimum conditions of 15 g rice bran, inoculum concentration of 5 x 10(6) spores mL(-1), and 60\% moisture level, HupA concentration was intensified to 518.93 mu g g(-1). Besides, HupA production by the fungal strain was further enhanced using gamma-irradiation mutagenesis. The final HupA production was significantly intensified following exposure to 0.5 KGy gamma radiation to 1327 mu g g(-1), which represents a 12.85-fold increase. This is the first report on the successful production of the natural fungal metabolite HupA under SSF. Moreover, the achieved yield in this study using agro-industrial wastes may contribute to reducing the cost of HupA manufacture.
The green synthesis of silica has been extensively explored over the last few decades, as silica compounds found in commercial products can cause negative effects on human health. This calls for alternative ways to produce silica that are safer, cheaper and more environmentally friendly. Some of the agricultural wastes proven to contain silica include rice husk, sugarcane bagasse, coconut shells and coconut husk. This paper describes the synthesis of silica from coconut husk waste, and its physical and optical properties for potential utilization in optical applications. Coconut husk was subjected to fire at 500-700 degrees C so as to form coconut husk ash (CHA), and was then treated with sulfuric acid to extract silica from the ash. Most of the weight degradation subsequently occurred at temperatures from 221 to 360 degrees C. X-ray fluorescence (XRF) analysis proved that 91.76\% of the silica was obtained, while major peaks on the X-ray diffraction (XRD) spectrum were observed after the acid treatment. Chemical bonds such as Si-O-Si, CH2, -OH and Si-OH were found in the spectrum of the Fourier transform infrared spectroscopy (FTIR). Furthermore, the particles displayed rod-like shapes and irregular sizes, but the particle with sizes ranging from 200-750 nm decreased after the acid treatment. The relationship between the absorption coefficient and photon energy was obtained by finding the optical energy gap, which was found to be 4.3 eV. These data points provide critical information when used in optical applications. The overall studies show that synthesized silica has great potential for use in optical field applications.
Human population growth, high consumption and unsustainable management of products and services are exceeding the sustainable use of natural resources. The use of disposable diapers, not only baby but also geriatric ones, reaches a high value, increasing considerably the urban solid residue generation. Currently, all this urban solid residue goes to landfills, taking up to 400 years to decompose, as most of its components are derived from oil. Its use as energy source, as it is already done with the cane bagasse, would bring great benefits, such as power generation and waste reduction. The objectives of this work were to identify the composition of each layer of a disposable diaper for babies and estimate the potential energy through combustion, employing the thermal analytical techniques TG/DTG/DTA, aiming at the reduction in the waste disposed in landfills, contributing in this way to an effective solid waste residue management. The layer 1 presented an endothermic peak at 165 degrees C, suggesting the presence of polypropylene, and layer 2 presented an endothermic peak at 130 degrees C, possibly consistent presence of polyethylene according to the manufacturer's information and infrared analyses. Through the DTA curves of layers 4, 5 and sodium polyacrylate (PSA), it is observed that the fusion temperatures of the polymer are around 425 degrees C indicating the presence of PSA in both layers. The disposable diaper combustion releases approximately 12 kJg(-1), lower than the heat released from sugarcane that is around 17 kJg(-1); if used to obtain energy would help the removal of the diaper from the environment by reducing space occupied by that residue in landfills, contributing to environmental sustainability.
This study examines the large amount of agricultural waste produced in Egypt between 2010 and 2019 by analysing data from various departments within the Agriculture Ministry. It also provides a comprehensive database on the biomass available from agricultural waste in Egypt and its potential applications for producing power, heat and chemical products. When biomass-pyrolysis systems powered by solar energy are used, research demonstrates the potential to convert agricultural waste into a variety of chemical compounds. This approach utilizes solar energy, a clean and renewable source, and has wide-ranging industrial and power generation applications. Despite Egypt's reliance on agriculture, the country currently utilizes little biomass for energy production and has not previously used it as a source for creating chemical products, which could potentially save on the imported oil used in these industries. The findings of the study are graphically presented using histograms, pie charts, etc. The overall production of residues reached the 30-Mt level in 2019. Because it contains the most rice-cultivated land, Dakahlia (Lower Egypt region) produces the highest percentage of the total residue (37.17\%). Qena governorate (Upper Egypt region) produces 1.14 metric tons of residues, with sugarcane accounting for 20.3\% of the total. A comprehensive database on the biomass available from agricultural waste in Egypt is provided. The overall production of residues reached the 30-Mt level in 2019. The potential applications for producing power, heat and chemical products are evaluated.
The synthesis of carbon quantum dots (CQDs) from agricultural waste is a promising approach for waste valorization. In the present work, CQDs were synthesized using sugarcane bagasse as a carbon precursor. The nanocomposite of CQDs with trimetallic strontium-titanium ferrite was synthesized with an ultrasonication approach. The structural, magnetic and optical features of the synthesized nanocomposite and pristine NPs were studied using different analytical techniques. The TEM micrograph of the nanocomposite reveals the distribution of CQDs (8-10 nm) along with the agglomerated ferrite NPs. To validate the results, the photocatalytic efficiency of the nanocomposite, NPs and CQDs was comparatively studied for the photodegradation of nitroaromatic pollutants viz. p-nitrophenol, martius yellow and pendimethalin under visible-light irradiation. A nanocomposite having a 2:1 w:w ratio of CQDs and Sr0.4Ti0.6Fe2O4.6 displays an excellent photocatalytic performance, with the degradation efficiency ranging from 91.2 to 97.4\%, as compared with 65.0-88.3\% for pristine NPs and CQDs. These results were supported by band gap and photoluminescence analyses. The promising photocatalytic potential of the nanocomposite over the pristine CQDs and ferrite NPs could be ascribed to the increased specific-surface area (101.3 m(2)/g), lowering in band gap coupled with fluorescence-quenching which facilitated the transfer of photoinduced charge carriers. The impact of parameters affecting the photocatalytic process viz. pH, catalyst dose and contact time was also investigated. On the basis of quenching and gas chromatography-mass spectrometry (GC-MS) studies, plausible degradation pathways were proposed. The results highlight the broad potential of designing substituted ferrite-CQDs-based nanocomposites as reusable and visible-light-driven photocatalysts.
The utilization of low value agro-industrial waste as valuable end product has become a key research priority in the recent years. Currently, the commercial cultivation of Pleurotus ostreatus using sawdust from rubber tree as the base substrate in Malaysia has been reported. However, the price and demand of the rubber tree sawdust (RS) have been increasing, affecting the overall production cost. Thus, a new inexpensive alternative substrate yet as effective as rubber tree sawdust is needed to replace the RS as the base substrate for the cultivation of P. ostreatus. In this study, the investigation on substrates from various agro-industrial waste in Malaysia was carried out. Nine different substrates were prepared in combinations in the ratio of 0.25 w/w and 0.5 w/w with empty fruit bunch (EFB), palm pressed fibre (PPF), sugarcane bagasse (SGB) and RS as an alternative substrate for the cultivation of P. ostreatus. These substrates were supplemented with fixed ratio of wheat bran and calcium carbonate to increase the yield of P. ostreatus. The number of days mycelium growth, yield (g/kg substrates), BE (\%) and nutrient compositions were studied for different the nine combinations of EFB, PPF and SGB to RS. The substrate of 25\%PPF + 25\%SGB + 50\%RS was found as the best formulation in term of growth performance, yield and biological efficiency (BE) (\%) with 35 days for first harvest at 318.88 g/kg and 79.72\%, respectively. Thus, the combination of EFB, PPF and SGB demonstrated a great potential as an alternative substrate for the cultivation of P. ostreatus when incorporated with RS.
Although beta-xylosidases with xylanase activity are preferential for the hydrolysis of xylan and production of xylitol, reports on their use are scarce. In this study, a multifunctional beta-xylosidase (XYL4) was identified. In addition to beta-xylosidase activity, XYL4 also exhibited xylanase and low ff-arabinosidase activity. The enzyme was able to hydrolyze bagasse xylan, oat spelt xylan, birchwood xylan, beechwood xylan, and corncob xylan, and showed the highest hydrolysis activity for corncob xylan. Structural modeling analysis indicated that XYL4 had an additional PA14 domain, which may play a key role in binding xylan substrates. Moreover, XYL4 was used to hydrolyze corncob xylan to produce xylose. When enzymatic hydrolysis and whole-cell catalysis were used to hydrolyze 100 g/L of corncob xylan, the xylose yields were 60.26\% and 35.85\%, respectively. Then, the Candida tropicalis was inoculated with the above hydrolysates for fermentation to produce xylitol. Using enzymatic hydrolysis and whole-cell catalysis, xylitol yields of 77.56\% and 73.67\% were obtained by C. tropicalis after the optimization of fermentation, respectively.
Quantitative chemical phenotyping is in an increasing demand to develop sweet sorghum genotypes targeted to accumulate carboxylate and polyphenolic secondary products as the plant-derived feedstocks for renewable biobased products including plastics. Of 24 sweet sorghum genotypes investigated, No. 5 Gambela (i) accumulated as much as sixfold higher (p < 0.05) trans-aconitic acid and redox-active secondary product concentrations and (ii) was most susceptible to lodging and was latest flowering. Partial least-squares calibration and prediction models were developed based on UV/visible spectra of juice and bagasse. Two-year field experiment indicated the accumulation of secondary products (carboxylates, polyphenolic chromophores, and alkali/alkaline earth metals) at the expense of fermentable sugar production. Liquid- (juice and methanol extract of bagasse) and solid-phase (bagasse without extraction) fluorescence excitation emission spectrophotometry with parallel factor analysis indicated the replacement of aromatic fingerprints by aliphatic structures from 2015 to 2016 in bagasse. In contrast, aromatic fluorophores accumulated in juice from 2015 to 2016, along with an increased UV/visible absorbance at 320 nm. Pearson's correlation analysis showed an interplay of the environmental (planting year) and genotype factors on the growth and chemical traits that could provide chemical speciation-based, bottom-up QA/QC protocols for biorefineries and chemical plants receiving the sweet sorghum bioenergy feedstock.
Organosulphur-modified biochar (BC) can be used as a green adsorbent for removing potentially toxic metal ions from aqueous solutions. In this study, sugarcane bagasse BCs (produced at pyrolysis temperatures from 300 to 700 degrees C) were modified in a single-step reaction with isothiocyanate. The performance and selectivity of raw and modified BCs for removing Cd2+, Ni2+, Pb2+ and Cr3+ from mono- and multi-element aqueous solutions were investigated. The characterisation of the BCs was performed by proximate analysis, Fourier transformed infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDS) and pyrolysis coupled to gas chromatography-mass spectrometry (Py-GC-MS). The results showed that the organosulphur modification increased S and N contents on the surface of the BCs, particularly isothiocyanate groups. The maximal adsorptions were observed for raw and modified BCs produced at 700 degrees C and pH 6. The adsorption kinetics of Cd2+, Ni2+, Pb2+ and Cr3+ before and after BC modification was best described by the pseudo-second order kinetic model. The results indicated that the removal of metal ions by modified-biochars follows the order Pb2+ > Cr3+ > Cd2+ similar or equal to Ni2+ and Cd2+ > Pb2+ > Ni2+ similar or equal to Cr3+ for mono-element and multi-element systems, respectively. The mechanisms involved in the adsorption were physisorption, chemisorption, complexation, precipitation, and ion exchange. The presence of other metal ions in the multi-element system caused a synergistic effect on adsorption of Cr3+, Cd2+ and Ni2+ and an antagonistic effect on adsorption of Pb2+. Organosulphur-modified BC can be an effective andselective adsorbent for removing Cd2+, Ni2+, Pb2+ and Cr3+ from aqueous solutions.
Agro-industrial by-products are a great option for ruminant feeding. Alternative feedstuffs in ruminant diets are important to increase diets and reduce production costs. The present study evaluated different levels of palm (Elaeis guineensis Jacq.) kernel cake inclusion in diets for feedlot-finished cull cows and their implications on the intake and digestibility of dry matter (DM) and nutrients, as well as animal performance. The experiment was carried out in Ribeirao do Largo, Bahia, Brazil. Thirty-six Holstein x Zebu crossbred cows were assigned to four treatments at the rate of nine cows per treatment. The animals were fed sugarcane bagasse (roughage 15\%) and concentrate (85\%). The treatments were no addition of palm kernel cake, 8\%, 16\%, or 24\% palm kernel cake inclusion in the total DM diet. Palm kernel cake inclusion influenced DM and nutrient intakes, which responded quadratically. The digestibility of DM, crude protein, and neutral detergent fiber corrected for ash and protein showed a quadratic response and maximum digestibility at 1.67\%, 5.24\%, and 3.68\% cake inclusion levels, respectively; values decreased thereafter. The total digestible nutrients decreased linearly based on cake inclusion levels. Treatments affected final body weight, mean daily gain, and feed conversion, which showed a quadratic response to increasing levels of the by-product in the diet and maximum values were at 11.98\%, 13.07\%, and 16.32\% inclusion, respectively. Palm kernel cake is a viable alternative ingredient for animal biological efficiency. The 16\% inclusion level in the total DM diet was the most appropriate for the finishing of cull cows in the feedlot.
The microbial production of industrial enzymes requires a large number of complex biochemical steps for purification which increases their production cost. Additionally, poor thermo-stability of the purified enzymes under the operational conditions along with the challenges in their recovery and subsequent reuse, limit their usage in an industrial bioprocess. Surface display of heterologous enzymes on bacterial cells appear to be a suitable alternative. Bacillus subtilis, the most well characterized Grain-positive bacterium, is being increasingly studied as a host for surface display. We displayed a glucose-tolerant beta-glucosidase (UnBgl1A) on the surface of B. subtilis cells using CWBb as the anchor protein. These cells displaying UnBgl1A (SD-01) were directly employed for biocatalysis without cell lysis and enzyme purification. The SD-01 cells elicited similar to 2 times more catalytic activity compared to the cells expressing the enzyme intracellularly (IN-01). The displayed enzyme and the purified enzyme elucidated similar glucose tolerance (IC50 similar to 0.9 M glucose), temperature optima (similar to 50 degrees C), and pH optima (similar to 6.0). The surface displayed UnBgl1A retained similar to 50\% activity after 4 h when stored at 50 degrees C whereas the purified UnBgl1A lost all its activity by the 4th hour. Additionally, the SD-01 cells could be efficiently reused for 3 sets of reactions. Further, supplementation of a cellulase cocktail with the cells of the SD-01 strain resulted in similar to 2 times more glucose release from sugarcane bagasse compared to supplementation with the purified UnBg11A. Therefore, displaying enzymes on the B. subtilis cell surface could be an attractive platform for the commercial production of industrial enzymes.
Background: beta-glucosidase is an important biomass-degrading enzyme and plays a vital role in generating renewable biofuels through enzymatic saccharification. In this study, we analyzed the transcriptome of Trichoderma harzianum HTASA derived from Hainan mangrove and identified a new gene encoding beta-glucosidase Bgl3HB. And the biochemically characterization of beta-glucosidase activity was performed. Results: Bgl3HB showed substantial catalytic activity in the pH range of 3.0-5.0 and at temperatures of 40 degrees C-60 degrees C. The enzyme was found quite stable at 50 degrees C with a loss of only 33.4\% relative activity after 240 min of heat exposure. In addition, all tested metal ions were found to promote the enzyme activity. The beta-glucosidase activity of Bgl3HB was enhanced by 2.12-fold of its original activity in the presence of 5 M NaCl. Surprisingly, Bgl3HB also showed a remarkable ability to hydrolyze laminarin compared to other measured substrates. Enzyme efficiency was examined in the sugarcane bagasse saccharification processes, in which Bgl3HB with 5 M NaCl worked better supplementing Celluclast 1.5L than the commercial Novozyme 188 ascertained it as an admirably suited biocatalyst for the utilization of agricultural waste. In this work, this is the first report of a halophilic beta-glucosidase from Trichoderma harzianum, and represents the beta-glucosidase with the highest known NaCl activation concentration. And adding 5 M NaCl could enhance saccharification performance even better than commercial cellulase. Conclusions: These results show that Bgl3HB has great promise as a highly stable and highly efficient cellulase with important future applications in the industrial production of biofuels.
The therapeutic value of specific fibres is partly dependent on their fermentation characteristics. Some fibres are rapidly degraded with the generation of gases that induce symptoms in patients with irritable bowel syndrome (IBS), while more slowly or non-fermentable fibres may be more suitable. More work is needed to profile a comprehensive range of fibres to determine suitability for IBS. Using a rapid in vitro fermentation model, gas production and metabolite profiles of a range of established and novel fibres were compared. Fibre substrates (n 15) were added to faecal slurries from three healthy donors for 4 h with gas production measured using real-time headspace sampling. Concentrations of SCFA and ammonia were analysed using GC and enzymatic assay, respectively. Gas production followed three patterns: rapid (=60 ml/g over 4 h) for fructans, carrot fibre and maize-derived xylo-oligosaccharide (XOS); mild (30-60 ml/g) for partially hydrolysed guar gum, almond shell-derived XOS and one type of high-amylose resistant starch 2 (RS2) and minimal (no differences with blank controls) for methylcellulose, another high-amylose RS2, acetylated or butyrylated RS2, RS4, acacia gum and sugarcane bagasse. Gas production correlated positively with total SCFA (r 0.80, P < 0.001) and negatively with ammonia concentrations (r -0.68, P < 0.001). Proportions of specific SCFA varied: fermentation of carrot fibre, XOS and acetylated RS2 favoured acetate, while fructans favoured butyrate. Gas production and metabolite profiles differed between fibre types and within fibre classes over a physiologically relevant 4-h time course. Several fibres resisted rapid fermentation and may be candidates for clinical trials in IBS patients.
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Hydrogels and organogels are polymer networks that can absorb large amounts of water and organic solvent, respectively. In this study, solvent absorption into the matrices of poly(glutaric acid-glycerol) hydrogel and organogel films amended with or without either iminodiacetic acid, sugarcane bagasse, pectin, corn fiber gum, or microcrystalline cellulose has been evaluated. Most of the starting materials used in this study, such as glycerol and the plant wall polysaccharides, are by-products of biofuel production. Finding uses for them would further biofuel initiatives worldwide. To that end, experimental results showed that water absorption increased when using polymer films composed of additional glycerol or plant cell wall polysaccharides. The amount of solvent absorbed into the control film increased when incubated in pH 10 buffer solutions but decreased when incubated in pH 4 buffer solutions and NaCl solutions when compared with absorption of water. Incubating the polymers in solvent at elevated temperatures increased the absorption rate. It was determined that the combined effects of pKa and polarity can be used to predict solvent absorption. Dimethylsulfoxide (DMSO) could be selectively extracted from or desorbed into films from other solvents. Erosion of the polymer films in DMSO ranged from 1.9 (+/- 0.2) to 34.7 (+/- 3.4)\%. In water, erosion ranged from 6.3 (+/- 3.2) to 32.7 (+/- 3.2)\%. The polymer films resorbed 3.3- and 2.3-fold more DMSO and water, respectively, when compared with the original amount of absorbed solvent. These materials are potentially good candidates for agricultural and medicinal applications because their ability to absorb, desorb, and erode can be tuned. (c) 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
The pore structure characteristics of cement mortar and concrete incorporating reclaimed asphalt pavement (RAP) fine aggregates as part replacements of natural fine aggregates (NAs) were studied using mercury intrusion porosimetry (MIP) technique. NAs were replaced by RAP at 25, 50, 75, and 100 \% by volume of total fine aggregates. Mineral admixtures, namely silica fume and activated sugarcane bagasse ash, were incorporated as part replacements of cement as well. MIP technique could identify the mesopores and macropores in the cementitious mixture. Porosity increases with an increase in RAP content in cementitious mixture, owing to larger and porous interfacial transition zone. Total intrusion pore volume increases with an increase in RAP content and is greater than the control mix irrespective of RAP content and mineral admixture. Mesopores and macropores follow a similar trend as total intrusion pore volume, suggesting finer and larger pores in RAP-inclusive cementitious mixtures. Threshold diameters were observed to initially decrease until 50 \% RAP content and to increase thereafter for RAP-inclusive cement mortar, suggesting easy penetration of chemical species for higher RAP content mixes. From pore classification studies, entrained air, large capillaries, medium capillaries, and small capillaries were also analyzed. Large capillaries follow a similar trend to threshold diameter, in which the former affects the transport processes in cementitious mixture. RAP-inclusive cementitious mixtures have the ability to resist freeze as well as thaw and salt decay; this is concluded indirectly from pore structure studies. The pore-mass fractal dimension has the ability to describe the pore-solid structure, whereas the pore-surface fractal dimension failed to do so for RAP-inclusive cementitious mixtures.
Due to the increasing price and decreasing amount of fossil fuels, energy obtained from biomass has received much attention in recent years. Biomass generally contains much water and they must be dried first to be used in conventional thernnochemical gasification process. However, a large amount of energy is consumed when the biomass are dried. In order to avoid the drying process, hydrothermal gasification processes, like as supercritical water gasification (SCWG), has attracted more attention because water can be used as a reaction medium, so that wet biomass does not need in the dried to be processed. The SCWG is related to present large hydrogen yields, but the excess of water inhibits the carbon monoxide production in the system and thus the syngas production is very low. The use of co-reactants appears as a strategy to promote syngas production in SCWG processes. In this work optimization techniques are applied in the minimization of Gibbs energy and in entropy maximization to study the thermodynamic effect of the use of CH4 and CO2 as co-reactant in the SCWG of microalgae biomass (Nannochloropsis sp.) and sugarcane bagasse. The Virial equation of state was used to represent the non-ideality of the systems. Both problems were formulated as optimization problems (non-linear programing) and the software GAMS in combination with the CONOPT solver, were used to solve them. Syngas with a H-2/CO molar ratio close to 2 (ideal for Fischer-Tropsch synthesis applications) was obtained with an addition of CO2 as a co-reactant. The calculated final temperatures were close to the initial temperature of the reaction in both systems, thus indicating low energy requirements for maintain these reactions.
Biochar may improve soil microbial and biochemical functions under abiotic stresses. In this research, we studied changes in soil microbial properties and processes after sugarcane bagasse biochar (SCB) application (1\% w/w) to a soil contaminated with Cd under saline conditions during an incubation experiment. SCB produced at 400 degrees C (B400) and 600 degrees C (B600) increased soil organic carbon (SOC) content by 89-127\% and dissolved organic carbon content by 21-70\%. NaCl salinity mobilized Cd by 16-19\%, while biochar immobilized Cd by 14-18\%, indicating the use of biochar would offset the increase in Cd availability induced by salinity. SCB application improved microbial and biochemical functions (up to 280\%) in the soils contaminated with Cd under salinity stress. B400 biochar was often more effective in improving the soil microbial properties and functioning than B600 biochar. SCB application reduced the detrimental effects of salinity-induced Cd toxicity on soil microbial community and enzyme activity mainly through retaining Cd and supplying C substrate for microbial uptake and activity. The factor analysis and redundancy analysis results also confirmed that SOC and Cd availability was the most important factors and accounted for a large portion of the variation in soil microbial properties and enzyme activities in saline Cd-contaminated soils amended with SCB. This study indicated that B400 applied at 1\% could be used in saline Cd-contaminated soils to protect the soil microbial communities from Cd toxicity, and to mitigate the potential stresses associated with the co-occurrence of Cd contamination and salinity on critical soil microbial and biochemical functions. (C) 2021 Elsevier Ltd. All rights reserved.
Long-term biocontrol strategies for termite management have limited success as the behavioral response exhibited by termites in the presence of entomopathogenic fungi was different. To minimize these responses, a study was conducted to attract the termites towards the treated area by augmenting fungal conidia with a mixture of attractants such as sugarcane bagasse, sawdust and cardboard powder. In laboratory experiments, mortality due to the horizontal transmission of Metarhizium anisopliae infection among Odontotermes obesus workers and soldiers was 50 to 98\% and 16 to 78\% for the five isolates tested. The foraging activity of workers and soldiers increased from 23 to 58\% for IWST-Ma13 when conidia were mixed with attractants. In a field study, the weight loss of stakes treated with conidial attractant decreased to 10.9 g compared to dry conidial treatments (19.3 g) for IWST-Ma13 after five months. Similarly, the width of mud galleries covering the tree bark was reduced when treated with conidial baits and gunny bags containing conidial attractant. In treated mounds, as the Acoustic emission signal voltage decreased from the threshold voltage level, the relative magnitude signal (RMS) remains low after five months of treatments with that of the control. From this study it was observed that the mixing of conidia with attractants could augment the dissemination potential of fungal infection among the termites. By adapting attractant based Metarhizium baits and dusting of conidial attractant mixture inside mounds may augment the dissemination potential in epizootic transmission of fungal infection. (c) Korean Society of Applied Entomology, Taiwan Entomological Society and Malaysian Plant Protection Society, 2013. Published by Elsevier B.V. All rights reserved.
In this study, two types of agricultural wastes, sugarcane bagasse (SB) and cassava root husks (CRHs), were used to fabricate biochars. The pristine biochars derived from SB and CRHs (SBB and CRHB, respectively) were modified using ZnO nanoparticles to generate modified biochars (SBB-ZnO and CRHB-ZnO, respectively) for the removal of Reactive Red 24 (RR24) from stimulated wastewater. Batch experiments were performed to evaluate the effects of ZnO nanoparticles' loading ratio, solution pH, contact time, and initial RR24 concentration on the RR24 adsorption capacity of biochars. The RR24 adsorption isotherm and kinetic data on SBB, SBB-ZnO3, CRHB, and CRHB-ZnO3 were analyzed. Results indicate that SB- and CRH-derived biochars with a ZnO nanoparticle loading ratio of 3 wt\% could generate maximum adsorption capacities of RR24 thanks to the double growth on the BET surface of modified biochars. The RR24 adsorption capacities of CRHB-ZnO3 and SBB-ZnO3 reached 81.04 and 105.24 mg g(-1), respectively, which were much higher than those of pristine CRHB and SBB (66.19 and 76.14, respectively) at an initial RR24 concentration of 250 mg L-1, pH 3, and contact time of 60 min. The adsorption of RR24 onto biochars agreed well with the pseudo-first-order model and the Langmuir isotherm. The RR24 adsorption capacity on modified biochars, which were reused after five adsorption-desorption cycles showed no insignificant drop. The main adsorption mechanisms of RR24 onto biochars were controlled by electrostatic interactions between biochars' surface positively charged functional groups with azo dye anions, pore filling, hydrogen bonding formation, and pi-pi interaction.
Overexploitation of nonrenewable energy resources and the problems associated with their unfair utilization have demanded for alternative sources of renewable energy. Lignocellulosic wastes including cereal straws, sugarcane bagasse, and banana stem, etc., have the potential for conversion into future fuel sources. Banana stem juice (BSJ) was extracted and explored for its potential in biogas production. The study found that BSJ can be fermented within 5-7 days using an anaerobic digestion process and is suitable for biogas production. The present study also focused on enhancing biogas production by adding microbial cultures with the substrate (BSJ) during the anaerobic digestion process. Five bacterial species, namely Streptomyces sp., Bacillus subtilis, Pseudomonas aeruginosa, Lactobacillus plantarum, and Desulfovibrio desulfuricans (separately, in combinations and a mixed culture) were investigated to find the efficiency for boosting biogas production. The optimal conditions as microbial dose, pH, retention time, and temperature for getting the highest yield of biogas through the anaerobic degradation process were analyzed. The best results were observed at 5\% microbial dose at pH 8. The P. aeruginosa demonstrated the best results among the cultures studied. On adding a 5\% dose of P. aeruginosa, at 8 pH and 30 degrees C temperature for a retention time of 5 days, 3,350 mL of biogas containing 75\% of methane share was produced from 1L of BSJ. Under the same conditions, chemical oxygen demand (COD) and total organic carbon (TOC) were reduced by 29\% and 38\%, respectively, in comparison to unfermented BSJ. It was found that the addition of microbial consortia during biogas production significantly improved the methane production and reduced the COD and TOC content.
Selection of suitable municipal solid waste management (MSWM) options is one of the major challenges in urban areas of the developing countries. Success of MSWM requires accurate data of generation rate, composition and physico-chemical characteristics of solid wastes. Improper handling of solid waste can have significant environmental and aesthetical impacts. The present study proposes a new method (applicability index - P-ik values) for identifying the most appropriate disposal option with the help of applicability values of Composting-C-P, Incineration-I-P and Landfill-L-P for individual components of MSW based on the results of the physico-chemical analysis of the collected representative solid waste samples from the study area, Dhanbad, India. The mean values of moisture content, carbon, hydrogen, oxygen, nitrogen, sulfur, volatile organic carbon, fixed carbon, ash content, density and calorific values (CV) of individual components were used as input values in this process. Based on the proposed applicability index (P-ik), the highest P-ik values were obtained for incineration (I-P) for plastics, polythene, paper, coconut shell, wood, cardboard, textile, thermocol (polystyrene), rubber, sugarcane bagasse, cow dung and leather wastes (I-P>C-P>L-P) due to high CV of these solid waste components; the highest P-ik values were obtained for composting (C-P) of kitchen waste (C-P>I-P>L-P); and the highest P-ik values for inert wastes were obtained for landfill option (L-P>I-P>C-P). The highest P-ik value for a particular waste for a specific treatment option signifies that the waste is suitable for treatment/disposal using that option.
Considerable amounts of fruit wastes and agro-food residues are generated worldwide as a result of food processing. Converting the bioactive components (e.g., carbohydrates, lipids, fats, cellulose, hemicellulose and lignin) in food wastes to biofuels is a potential remediation approach. This study highlights the characterization and hydrothermal conversion of several fruit wastes and agro-food residues such as aloe vera rind, banana peel, coconut shell, lemon peel, orange peel, pineapple peel and sugarcane bagasse to hydrogen-rich syngas through supercritical water gasification. The agro-food wastes were gasified in supercritical water to study the impacts of temperature (400-600 degrees C), biomass-to-water ratio (1:5 and 1:10) and reaction time (15-45 min) at a pressure range of 23-25 MPa. The catalytic effects of NaOH and K2CO3 were also investigated to maximize the hydrogen yields and selectivity. The elevated temperature (600 degrees C), longer reaction time (45 min) and lower feed concentration (1:10 biomass-to-water ratio) were optimal for higher hydrogen yield (0.91 mmol/g) and total gas yield (5.5 mmol/g) from orange peel. However, coconut shell with 2 wt\% K2CO3 at 600 degrees C and 1:10 biomass-to-water ratio for 45 min revealed superior hydrogen yield (4.8 mmol/g), hydrogen selectivity (45.8\%) and total gas yield (15 mmol/g) with enhanced lower heating value of the gas product (1595 kJ/Nm(3)). The overall findings suggest that supercritical water gasification of fruit wastes and agro-food residues could serve as an effective organic waste management technology with regards to bioenergy production. (C) 2015 Elsevier Ltd. All rights reserved.
Ion exchange resins commonly have a single functionality for either cations or anions. Resins that have a dual functionality for both cations and anions are uncommon. The objective of this study was to create dual-functional ion exchange resins derived from soybean hulls, sugarcane bagasse and corn stover. Dual-functional resins were prepared by two separate two-step processes. In the first two-step process, by-products were reacted with a solution of citric acid in order to impart additional negative charge, and then reacted with the cross-linking reagent dimethyloldihydroxyethylene urea (DMDHEU) and a quaternary amine (choline chloride) to add positive charge to the lignocellulosic material. In the second two-step process, the order of reaction was reversed, with positive charge added first, followed by the addition of negative charge. These combined reactions added both cationic and anionic character to the by-products as evidenced by the increased removal from solution of copper (Cu2+) cation and the chromate (CrO42-) anion compared to unmodified by-products. The order of reaction appeared to slightly favor the functionality that was added last. That is, if negative charge was added last, the resulting resin sequestered more copper ion than a comparable resin where the negative charge was added first and vice-versa. Cu2+ and CrO42- were used as marker ions in a solution that contained both competing cations and anions. The dual-functional resins adsorbed as much as or more of the marker ions compared to commercial cation or anion exchange resins used for comparison. None of the commercial resins exhibited dual-functional properties to the same extent as the by-product-based resins. Published by Elsevier Ltd.
Sugarcane-molasses based distillery waste is a threat to environment for its safe disposal due to complexation of endocrine-disrupting chemicals (EDCs) containing mixture of organic pollutants. This study revealed that distillery sludge contains not only mixture of complex organic pollutants but also retains high quantity of Fe (5264.49), Zn (43.47), Cu (847.46), Mn (238.47), Ni (15.60), and Pb (31.22 mg kg(-1)) which enhances the toxicity of sludge to the environment. The major identified organic compounds were benzene, 1-ethyl-2-methyl, benzene, 1-ethyl-4-methyl benzoic acid, 3,4,5-tris(TMS oxy), TMS ester; hexanedioic acid, dioctyl ester; stigmasterol TMS ether; 5a-cholestane, 4-methylene; campesterol TMS; beta-sitosterol and lanosterol. These compounds are listed under the EDCs also as per U.S. Environmental Protection Agency. However, the phytoextraction potential of growing native weeds and grasses i.e. Argemone mexicana, Saccharum munja, Cynodon dactylon, Pennisetum purpureum, Chenopodium album, Rumex dentatus, Tinospora cordifolia, Calotropis procera and Basella alba revealed the high accumulation of Fe, Zn, Cu, Mn, Ni, and Pb in their root and leaves compared to shoot. This indicated high accumulation and translocation capabilities of these plants. Further, the bioaccumulation coefficient factor (BCF) and translocation factor (TF) was found >1 for majority of plants for various metals. Thus, this given strong evidence for hyperaccumulation tendency of these native weeds and grasses from complex polluted sites. Furthermore, the ultrastructural observations of root tissues also revealed the deposition of heavy metals at various cellular components without any apparent toxic effects. This indicated the variable adaptive characteristics of these plants growing at a hazardous waste polluted site. Thus, the study given a strong evidence for application of these weeds and grasses as tools for in-situ phytoremediation and eco-restoration of polluted sites.
Heterogeneous catalysis for biodiesel production via esterification has emerged as a preferred route as it permits to overcome the disadvantages associated to homogeneous catalysis, which presents serious drawbacks that affect biodiesel production and increase its costs such as corrosivity, difficult removal, and non-reuse of the catalyst. This study evaluated the esterification of oleic acid (OA) using CoFe2O4 and MnFe2O4 ferrite magnetic nanoparticles (MNPs) coated with sulfonated lignin (SL). SL was synthesized from sugarcane bagasse lignin employing acetyl sulfate (sulfonating agent). Two different proportions of reactants were adopted, obtaining the solids SL5 and SL7.5-posteriorly incorporated into the MNPs. Reaction parameters evaluated were as follows: time (4 and 6 h) and temperature (80 and 100 degrees C), with other parameters fixed. The catalysts were characterized by XRD, BET method, SEM, TGA, and elemental analysis. The sulfonic group contents were determined by acid-base titration. The conversion of OA into methyl esters was determined by GC-MS and FTIR. Elemental analysis showed that SL5 and SL7.5 have 2.68\% of sulfur content by mass and the following minimal molecular formulas C9H10,52O5,62(SO3H)(0,18) and C9H10,52O5,62(SO3H)(0,17). XRD and TGA data evidenced that coated MNPs exhibit incorporation percentage of SL higher than 50\%, with the best results for CoFe2O4-SL5 (79.5\%) and CoFe2O4-SL7.5 (78.5\%). GC-MS and FTIR data revealed that the highest OA conversions were achieved under 6 h and 100 degrees C. In addition, CoFe2O4-SL5 and MnFe2O4-SL7.5 exhibited the best catalytic performances in the esterification reactions with conversions of OA into fatty acid methyl esters of approximately 80\%.
Inorganic salt pretreatment of lignocellulosic biomass has proven to be an efficient way to increase the efficiency of enzymatic saccharification. However, it is not clear that this improvement is the result of modification of the lignocellulosic substrate after pretreatment, or removal of inhibitor, or enhancement of cellulase or a combination of these events. Therefore, this study aimed to analyze the effects of inorganic salts on kinetics of cellulase enzymes (celluclast 1.5L and accellerase 1500). Two substrates rich in cellulose content {[
Biochar is carbonized biomass obtained from sustainable sources detained in soil to improve the fertility of agricultural soil. The porous nature and absorptive properties of biochar have the potential to immobilize elements, which provide an ideal environment for the soil biota that helps to enhance the growth of plants. In this study, different feedstocks such as sugarcane bagasse (SB), plant material (PM), and manure biomass (MB) were pyrolyzed for the production of biochar. Elemental contents of the feedstock's and voucher were determined with the help of the atomic absorption mass spectrometer. Elemental concentration was significantly increased in biochars compared to raw materials. A pot experiment with 2\% and 4\% of each biochar was conducted on chili plant to elucidate the beneficial effects on plant growth as compared to control soil, the elemental analysis of the plant soil contained each biochar showed to progressively increase in the concentration of manganese (Mn), zinc (Zn), and copper (Cu) as these are trace elements and have important role in plant growth system. Microbial population in biochar amended soil was also evaluated to check the impact on bacterial populations. Soil with 2\% biochar showed 16\% increase in the microbial load while biochar with 4\% increased the microbial population up to 50\%. Furthermore, biochar treatments to red soil increased the elemental Cu, Mn, and Zn concentrations, respectively, and also increased the soil pH. Consequently, soil productivity increased in terms of plant growth by balancing the concentration of elements and also increased the microbial population. It is concluded that biochar use in agriculture could be effective for the soil fertility and increasing plant growth and soil bacteria.
This study characterized a 50 kDa beta-glucosidase (BGL50) produced by the thermophilic fungus Myceliophthora thermophila M.7.7 in solid state cultivation using a mixture of (1:1) sugarcane bagasse and wheat bran. The crude extract zymogram showed two isoforms of beta-glucosidase with approximately 50 and 200 kDa, which were separated by gel filtration chromatography. The characterization of BGL50 showed optimum activity at 60 degrees C and pH 5.0 when 4-nitrophenyl beta-D-glucopyranoside (pNPG) was used as the substrate, whereas when using cellobiose, the highest activity was observed at 50 degrees C and pH 4.5. Several ions and reagents produced different effects on the enzyme activity depending on the substrate and there was complete inhibition with Cu2+ and Fe3+ for both substrates. In addition, nine phenolic compounds showed no inhibitory effects on the enzyme, a significant feature since beta-glucosidase is used for the saccharification of lignocellulosic biomass that generates several phenolic compounds. Kinetic studies revealed competitive inhibition by glucose when pNPG was used, with a K-i value of 1.5 mM and a significantly lower K-m (0.52 mM) than for cellobiose (8.50 mM). The thermodynamic parameters showed that BGL50 is very stable at 60 degrees C displaying a half-life of 855.6 min but it is easily denatured above this temperature. The results emphasize the importance of investigating potential beta-glucosidases based on cellobiose instead of using only pNPG since, in the industrial process, the enzyme will act on this natural substrate. In addition, understanding the thermostability of the enzyme is an important contribution to enzyme technology.
In situ stabilization of trace elements by adding cheap amendments is an emerging technology for large-scale soil remediation. Various amendments have been examined well in the literature, but related have focused predominantly on short-term laboratory scale incubation or pot experiments. This study applied dolomitic lime at 40 ton ha(-1), oyster shell (OS) at 80 ton ha(-1), and sugarcane bagasse compost (SC) at 60 ton ha(-1) to a paddy field in Taiwan for two rice (Oryza saliva L.) cropping seasons. The aims of study were to gain an understanding of the bioavailable concentrations of Cr, Ni, Cu, and Zn in the amended soil and the metal uptake of rice for practical amendment use in field-scale remediation of contaminated soils. The treatments of lime and OS significantly (p < 0.05) decreased the 0.1 N HCl-extractable metals in the soil. The increase in soil pH was the key factor in decreasing the bioavailable pool of metals in the soil by using lime and OS. The concentrations of Cu, Zn, and Ni in the brown rice were substantially reduced only through the addition of OS, and thus OS met the requirement of being a cheap, locally available, and environmentally compatible amendment for field-scale soil remediation. The translocation of Cr in rice plants is heavily restricted, and thus no significant differences in Cr uptake by rice grain were observed between the different amendment treatments. However, SC is not recommended as an immobilization agent because it caused a pH decrease in the amended soil. (C) 2018 Elsevier Ltd. All rights reserved.
Co-cultivation of mutant Penicillium oxalicum SAUE-3.510 and Pleurotus ostreatus MTCC 1804 was evaluated for the production of xylanase-laccase mixture under solid-state fermentation (SSF) condition. Growth compatibility between mutant P. oxalicum SAUE-3.510 and white rot fungi (P. ostreatus MTCC 1804, Trametes hirsuta MTCC 136 and Pycnoporus sp. MTCC 137) was analyzed by growing them on potato dextrose agar plate. Extracellular enzyme activities were determined spectrophotometrically. Under derived conditions, paired culturing of mutant P. oxalicum SAUE-3.510 and P. ostreatus MTCC 1804 resulted in 58\% and 33\% higher levels of xylanase and laccase production, respectively. A combination of sugarcane bagasse and black gram husk in a ratio of 3: 1 was found to be the most ideal solid substrate and support for fungal colonization and enzyme production during co-cultivation. Maximum levels of xylanase (8205.31 perpendicular to 168.31 IU g(-1)) and laccase (375.53 perpendicular to 34.17 IU g(-1)) during SSF were obtained by using 4 g of solid support with 80\% of moisture content. Furthermore, expressions of both xylanase and laccase were characterized during mixed culture by zymogram analysis. Improved levels of xylanase and laccase biosynthesis were achieved by co-culturing the mutant P. oxalicum SAUE-3.510 and P. ostreatus MTCC 1804. This may be because of efficient substrate utilization as compared to their respective monocultures in the presence of lignin degradation compounds because of synergistic action of xylanase and laccase. Understanding and developing the process of co-cultivation appears productive for the development of mixed enzyme preparation with tremendous potential for biobleaching.
The aim of this study was to identify the traits that most affect production of sugarcane, fiber and lignin content (LIG) with a view toward optimizing the process of assessment and selection of families of energy cane. Fifty full-sibs families were assessed using an incomplete-block design, with five replications. The traits assessed were mean stalk height (SH), mean stalk diameter (SD), mean number of stalks per plant (NS), mean stalk weight (SW), fiber content (FIB), LIG, tons of cane per hectare (TCH), tons of fiber per hectare (TFH) and tons of lignin per hectare (TLH). Based on path analysis, it was possible to observe that the traits SW and NS, in that order, exhibited the greatest direct effects on TCH, TFH, and TLH. These traits they were indirectly affected to a greater degree by NS. The direct effects of FIB, LIG, SH, and SD on TCH, TFH, and TLH were smaller than the residual effects on the analyses carried out, showing their little importance in the selection process. The increase of TFH and TLH mainly occur due to greater biomass production, which is associated with greater tillering capacity and with the SW of the families. Thus, selection of families with greater FIB might not show genetic gains if the mean values for TCH of their offsprings are low. Therefore, selection of the best families for energy cane should be carried out based on TCH, which may be estimated by way of NS and SW.
Developing a special kind of material for rapid and efficient capture of Hg(II) in emergency pollution events or industrial wastewater has always been a headachy task. Herein, porous ZIF-8 with a high surface area was prepared via a facile method for the ultra-fast removal of Hg(II) from diverse water bodies, and anchoring it on the sugarcane bagasse (SCB) could address its separation problem. ZIF-8 was wider pH adaptable (2-7), of which the conspicuous adsorption performance was insensitive to ionic strength (Cl-, SO4 2-, NO3- ) even at an extremely high level (10,000 mg/L, Re>98.73 \%). ZIF-8 can efficaciously enrich a large amount of Hg(II) in a short period (1 min, 519.6 mg). The theoretical maximum adsorption capacity of ZIF-8 estimated from the Langmuir isotherm was 2195.10 mg/g, which was endowed by that the Hg(II) with higher ionization energy was capable of replacing the Zn(II) to form more stable metal-ligand complexes with dimethylimidazole. Meanwhile, ZIF-8 can also achieve excellent affinity to Hg(II) in binary and multi-metal mixed solutions, and it can maintain high performance (86.25 \%) after 5 cycles, the leaking Zn(II) in the treated water could be utilized as the raw material to synthesize ZIF-8. Noteworthy, the as-preparing ZIF-8 can efficiently capture Hg(II) in complex environments such as natural water and artificial industrial wastewater in a short time (t<60 min, Re>99.63 \%). Therefore, the as-prepared material possesses outstanding adsorption performance and could be a promising candidate in the broad practical applications for ultra-fast and high-capacity capture of high mercury levels.
The present investigation attempted to examine the defluoridation feasibility onto the extracted nanocellulose/PVA polymer composites. Nanocellulose were derived from sugarcane bagasse and blended with PVA (polyvinyl alcohol) polymer matrix. The defluoridation potential of nanocellulose/PVA was observed to be significantly dependent on the various operational factors including pH, time interval, etc. the Temkin isotherm (R-2 = 0.989) as well as the Langmuir isotherm equation (R-2 = 0.982) could well fit with the investigational data. Following the Langmuir isotherm, the maximum monolayer adsorption capacity for fluoride elimination at 25 degrees C was obtained as 11.363 mg g(-1). The nature of rate-limiting steps involved in defluoridation process might be effectively predicted by pseudo-second-order kinetics. Values of thermodynamic state properties achieved as of the thermodynamic analysis showed that the defluoridation process was spontaneous, exothermic, and feasible. The diffusion and mass transfer study were estimated by following the Boyd's model. Average effective diffusion coefficient (D-e) at various initial fluoride concentrations (4-10 mg L-1) was obtained as 15.3343x10(-7) m(2)s(-1) and the estimated magnitude of the mass-transfer coefficient (K-f) was 0.0346x10(-9) m s(-1) (temperature = 298 K, C-0= 6 mgL(-1)). An ANN (artificial neural network) model applied to optimize and simulate the defluoridation procedure. Furthermore, continuous flow column reactor was conducted to investigate the practical applicability of composites in the defluoridation process. The Yoon-Nelson and the Thomas model exhibited excellent conformity with the breakthrough curves. Nanocellulose/PVA satisfactorily eliminated fluoride from its aqueous solution and can be considered as a suitable bio-sorbent for defluoridation.
In this work, the effects of using natural lignocellulosic-based adsorbents from sugarcane bagasse (SC), cornstalk piths (CP), and corn cob (CC) on the physicochemical properties and quality of fried oils were studied. The properties of lignocellulosic biomasses were examined using X-ray diffraction (XRD), scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FTIR). Moreover, the changes in the physicochemical properties of fresh, fried oils (for 4, 8, 12, 16 and 20 h) and adsorbents-treated oils were examined. The XRD results revealed that SC and CP biomasses have more amorphous regions than CC biomass, which had the highest crystallinity percentage. The results also showed that lignocellulosic biomasses enhanced the quality of the used oils. SC was the most effective biomass to enhance the properties of the used sunflower oil. For instance, the acid value of oil samples fried for 20 h reduced from 0.63 +/- 0.02 to 0.51 +/- 0.02 mg KOH/g oil after SC biomass treatment. For the peroxide value, the SC biomass treatment reduced it from 9.45 +/- 0.56 (fried oil for 20 h) to 6.91 +/- 0.12 meq O-2/kg. Similarly, SC biomass adsorbent reduced the p-Anisidine Value (p-AV) of the used oil (20 h) from 98.45 +/- 6.31 to 77.92 +/- 3.65. Moreover, SC adsorbents slightly improved the lightness of the used oils (20 h). In conclusion, natural lignocellulosic biomasses, particularly SC, could be utilized as natural adsorbents to improve the oil quality. The results obtained from this study could help in developing sustainable methods to regenerate used oils using natural and cheap adsorbents.
Incineration and landfilling offer possibilities for addressing high-rate management of COVID-waste streams. However, they can be costly and environmentally unsustainable. In addition, they do not allow to convert them to fuels and chemicals as waste-to-energy and waste-to-product technologies. Therefore, we analyzed whether integrating hydrothermal carbonization (HTC) and pelletization can allow converting the surgical face mask (SFM) and biomass to composite plastic-fiber fuel (CPFF). We blended the plastic material and corncob, peanut shell, or sugarcane bagasse at the proportion of 50:50 (\%, dry mass basis) for HTC. We performed the thermal pretreatment of blends in an autoclaving reactor at 180 degrees C and 1.5 MPa. Then we pelletized the hydrochars in a presser machine at 200 MPa and 125 degrees C. By analyzing the evidence from our study, we recognized the viability of combining the SFM and agricultural residues for CPFF from comparable technical features of our products to standards for premium-grade wood pellets. For instance, the elemental composition of their low-meltable ash was not stoichiometrically sufficient to severely produce slagging and fouling in the equipment for thermal conversion. Although they contained synthetic polymers in their structures, such as polyethylene from filter layers and nylon from the earloop, they emitted CO and NOx below the critical limits of 200 and 500 mg m(-3), respectively, for occupational safety. Therefore, we extended the knowledge on waste-to-energy pathways to transform SFM into high-quality hybrid fuel by carbonization and pelletization. Our framework can provide stakeholders opportunities to address plastic and biogenic waste in the context of a circular economy.
Fruit fly pests in north-eastern Brazil include several species of the genus Anastrepha and the Mediterranean fruit fly Ceratitis capitata (Wiedemann). The most common species are Anastrepha zenildae Zucchi, the South American fruit fly Anastrepha fraterculus (Wiedemann), the West Indian fruit fly Anastrepha obliqua (Macquart) and Anastrepha sororcula Zucchi. In this study, attempts were made to mass-rear A. zenildae and A. fraterculus. The objective was to adapt local populations to laboratory conditions and develop mass-rearing systems for further utilization in integrated area-wide control programmes. Small colonies initially fed on guava fruits were developed in the laboratory. Adults were fed a diet made of brown sugar (60\%), hydrolysed corn protein (26\%), brewer's yeast (5\%) and honey (9\%). Adult diets with other combinations of ingredients were also tested. The colonies of A. zenildae and A. fraterculus achieved mating and egg hatch rates of 32 and 39\%, respectively. The best diets for adults, resulting in good egg hatch, were as follows: diet B - brown sugar (60\%), hydrolysed corn protein (26\%), brewer's yeast (5\%) and honey (5\%); diet C - hydrolysed corn protein and white sugar (1: 3); and diet D - soybean protein and white sugar (1: 3). The best larval diet was based on 18\% sugarcane bagasse and 9\% protein. Adult mortality during the first 15 days was still high, over 50\%. Adult recovery from pupae was over 70\%. The best oviposition substrate was an agar-coated glass bottle. Mating compatibility was highest for A. fraterculus from the state of Sao Paulo. Mating between A. fraterculus and A. zenildae yielded no viable eggs.
This study investigated the adsorption performance of biochar produced from different types of urban biowaste material viz., sugarcane bagasse (SB), brinjal stem (BS), and citrus peel (CP) for removal of heavy metal ions (Pb, Cu, Cr, and Cd) from aqueous solution. The effects of biowaste material, dosage of biochar, solution pH, and initial concentration of heavy metal ions and isotherm models were performed to understand the possible adsorption mechanisms. The results showed that the biochar derived from BS and SB removes Cu (99.94\%), Cr (99.57\%), and Cd (99.77\%) whereas biochar derived from CP removes Pb (99.59\%) and Cu (99.90\%) more efficiently from the aqueous solution. Biochar derived from BS showed maximum adsorption capacity for Cu (246.31 mg g(-1)), Pb (183.15 mg g(-1)), and Cr (71.89 mg g(-1)) while the biochar derived from CP showed highest for Cd (15.46 mg g(-1)). Moreover, biochar derived from BS and SB has more polar functional groups and less hydrophobicity than the biochar derived from CP. This study reveals that solution pH and biochar doses play a major role in removal of heavy metal ions from aqueous solution. The results of Langmuir model fitted well for Pb and Cu while the Freundlich model for Cr and Cd. Our study concludes that the biochar derived from different biowaste materials adsorbs heavy metal ions majorly through surface complexation and precipitation processes. The results of this study will be very useful in selecting the effective urban biowaste material for making biochar for heavy metal removal from the aqueous environment.\{GRAPHIACAL ABSTRACT\
In this study, we explored the potential of a newly prepared nano-zero valent zinc (nZVZn), biochar (BC)/nZVZn and BC/hydroxyapatite-alginate (BC/HA-alginate) composites for the removal of inorganic As species from water. Relatively, higher percentage removal of As(III) and As(V) was obtained by nZVZn at pH 3.4 (96\% and 94\%, respectively) compared to BC/nZVZn (90\% and 88\%) and BC/HA-alginate (88\% and 80\%) at pH 7.2. Freundlich model provided the best fit (R-2 = up to 0.98) for As(III) and As(V) sorption data of all the sorbents, notably for nZVZn. The pseudo-second order model well-described kinetics of As(III) and As(V) (R-2 = 0.99) sorption on all the sorbents. The desorption experiments demonstrated that the As removal efficiency, up to the third sorption/desorption cycle, was in the order of nZVZn similar to BC/HA-alginate (88\%) > BC/nZVZn (84\%). The Fourier transform infrared spectroscopy depicted that the -OH, -COOH, Zn-O and Zn-OH surface functional groups were responsible for the sorption of As(III) or As(V) on the sorbents investigated here. This study highlights that removal of As species from water by BC/nZVZn composite can be compared with nZVZn, suggesting that integrating BC with nZVZn could efficiently remove As from As-contaminated drinking water. Novelty statement This is the first study to explore the potential of a newly prepared sugarcane bagasse biochar/nano-zerovalent zinc (BC/nZVZn) based composite for the removal of inorganic arsenic (As) species from water. The results indicated high percentage removal of As(III) and As(V) from water by BC/nZVZn that were comparable to nZVZn alone.
Utilization of greywater can reduce water stress if, it is used as an alternative source of water for non-potable use, but it requires careful treatment to remove the contaminants including micropollutants associated with the use of a large number of personal care products. The present paper deals with the batch as well as continuous adsorption study for the treatment of greywater using activated carbons prepared from sawdust, sugarcane bagasse and pine needles. Characterization of adsorbents were done through sophisticated instruments such as FE-SEM, FTIR and BET. The optimum conditions in batch mode for the removal of contaminants are found as pH 7, contact time 240 min. and adsorbent dose 8 g/L with initial COD of greywater as 554 mg/L and BOD as 120 mg/L. For isotherms study, models such as Langmuir, Freundlich and Temkin were used whereas for kinetic study pseudo-first-order, pseudosecond -order and Elovich models were investigated to validate the experimental data. The column adsorption study has been performed to carry out breakthrough analysis of the column bed with respect to COD and BOD removal. To understand the behaviour of breakthrough curves three models viz. BohartAdams, Yoon-Nelson and Thomas models have been tested. Out of these adsorbents, the sawdust activated carbon is found to be more efficient. To maintain the concentration of pollutants in treated water below the permissible limit as per CPCB (Central pollution control board), India, a coupled unit of sand and the adsorbent column was investigated in continuous mode. The present investigation appears to be highly competitive to the published literature. (C) 2019 Elsevier B.V. All rights reserved.
The pyrolysis kinetics of xylan, cellulose, and eight lignocellulosic biomass samples (including corn stover, cotton stalk, palm oil husk, pine wood, red oak, sugarcane bagasse, switchgrass, and wheat straw) were measured in a TA SDT Q600 thermogravimetric analyzer. The kinetic data of xylan and cellulose were fitted to a distributed activation energy model (DAEM) where the activation energies for the pyrolysis of each reactant followed a Gaussian distribution. The activation energy distribution peaks were centered at 178.3 and 210.0 kJ mol(-1) for xylan and cellulose respectively. The standard deviations of the activation energy distributions for xylan and cellulose were 5.85 and 0.94 kJ mol(-1). A three-parallel-DAEM-reaction model was used to fit the pyrolysis kinetics of the lignocellulosic biomass feedstocks. The model assumes that biomass contains three independent reacting pseudo-components all of which have a Gaussian distribution for their activation energies. The first, second and third pseudo-components represent the fractions of hemicellulose, cellulose and lignin, respectively. The activation energy distribution peaks for the three pseudo-components were centered at 169.7-186.8, 204.2-212.5, and 237.1-266.6 kJ mol(-1) for the different biomass feedstocks. The standard deviations of the activation energies were 4.6-8.8, 0.7-1.8, and 26.5-41.8 kJ mol(-1) for the hemicellulose, cellulose and lignin fractions respectively. This indicates that the activation energy distribution for lignin has the widest distribution, and cellulose has the narrowest distribution. The biomass compositions obtained by the fitting of the pyrolysis kinetics agreed well with published values obtained from wet chemical analysis techniques.
Solid-state fermentation can be used to produce pectinases using agro-industrial byproducts. However, heat and mass transfer limitations make it difficult to control the temperature within the bioreactor, especially at large scale, so reliable scale-up strategies are essential. In the current work, we scaled up the production of pectinases in packed-bed bioreactors, from 12 g to 30 kg of dry substrate, the biggest scale yet reported for pectinase production. When compaction occurred, bed temperatures up to 47 degrees C were recorded and the pectinase activity in different regions of the bed at 26 h varied from 11 to 28 x 10(3) U kg(-1). When compaction was avoided, the maximum bed temperature was 32 degrees C and the pectinase activity at 26 h varied from 17 to 20 x 10(3) U kg-1. The best result was obtained with a 40-cm high bed containing 27 kg of wheat bran and 3 kg of sugarcane bagasse, with switching of the temperature of the saturated inlet air between 24 degrees C and 32 degrees C. Under these conditions, the maximum productivity was 1840 U kg(-1) h(-1) at 10 h. We propose that the process can be scaled up to production scale by maintaining the same bed height and operational strategy, while increasing the width of the bed to several meters. If the superficial velocity of the air is maintained constant at 0.1 m s(-1), then the performance at scales involving several tonnes of solid substrate should be similar to that obtained in pilot-scale bioreactor in the current study. (C) 2015 Elsevier B.V. All rights reserved.
The sugarcane molasses-fed distillery wastewater (DWW) has very high biochemical and chemical oxygen demand (BOD and COD) and has to be treated to meet the regulatory discharge standards and to recover its energy content. The catalytic thermal pretreatment (or catalytic thermolysis, CT) is a novel pretreatment process to recover the majority of its energy content with consequent COD and BOD removal. The present paper deals with the CT of DWW using CuO catalyst. Experiments were conducted in a 1 dm(3) stainless steel pressure reactor in a batch mode in the temperature range of 100-140 degrees C and corresponding autogenous pressure with CuO mass loading in the range of 2-5 kg/m(3). The initial pH (pH(0)) is found to have profound impact on the efficiency of thermolysis in COD removal and the optimum pHo is found to be 2.At 140 degrees C with 3 kg/m(3) catalyst loading and pH(0) 2, a maximum of 60\% COD could be reduced. The CT process follows a two step mechanism: each step obeys the first order reaction kinetics with respect to COD and a fractional order 0.37 and 0.29 with respect to catalyst mass loading for the first and second steps, respectively. The CT process results in the formation of settleable solid residue and the slurry obtained after the thermolysis exhibited very good filtration characteristics. At 140 degrees C and pH(0) 2, the solid residue had a C:H atomic ratio of 1:1.08 with a heating value of 21.77 MJ/kg. The residue can be used as a fuel in the combustion furnaces and the ash obtained can be blended with organic manure and used in agriculture/horticulture. (C) 2007 Elsevier B.V. All rights reserved.
Soil disinfestation is an important agricultural practice to conquer soil-borne diseases and thereby ensure crop productivity. Reductive soil disinfestation (RSD) had been developed as an environmentally friendly alternative to chemical soil disinfestation (CSD). However, the differences between CSD and RSD on soil-borne pathogen suppression and fungal community structure remain poorly understood. In this work, five treatments, i.e., untreated soil (CK), CSD with 0.5 t ha(-1) dazomet (DZ), RSD with 10 t ha(-1) ethanol (ET), 15 t ha(-1) sugarcane bagasse (SB), and 15 t ha(-1) bean dregs (BD), were performed to investigate their influences on disinfestation efficiency, fungal abundance, diversity, and community structure via quantitative PCR and high-throughput sequencing. RSD-related treatments, especially the BD treatment, effectively alleviated soil acidification and salinization. The fungal abundance and microbial activity considerably increased in the BD treatment and significantly declined in the DZ treatment as compared to the CK treatment. Moreover, both CSD and RSD-related treatments significantly inhibited the population of Fusarium oxysporum and the relative abundance of genus Fusarium. Fungal community structure was notably altered by CSD and RSD practices. Furthermore, both CSD and RSD harbored a distinct unique microbiome, with the DZ treatment dominated by the genus Mortierella and BD treatment predominated by the genera Zopfiella, Chaetomium, and Penicillium. Taken together, these results indicate that the BD treatment could considerably alleviate the soil deterioration, improve soil microbial activity, and reassemble a non-pathogen unique microbiome that have more disease-suppressive agents and thus might be a promising disinfestation practice to control soil-borne disease in monoculture system.
In bacterial cellulase systems, glycoside hydrolase family 9 (GH9) cellulases are generally regarded as the major cellulose-degrading factors besides GH48 exoglucanase. In this study, umcel9A, which was cloned from uncultured microorganisms from compost, with the encoded protein being theme C GH9 cellulase, was heterologously expressed in Escherichia coli, and the biochemical properties of the purified enzyme were characterized. Hydrolysis of carboxylmethylcellulose (CMC) by Umcel9A led to the decreased viscosity of CMC solution and production of reducing sugars. Interestingly, cellobiose was the major product when cellulosic materials were hydrolyzed by Umcel9A. Six representative carbohydrate-binding modules (CBMs) from different CBM families (CBM1, CBM2, CBM3, CBM4, CBM10, and CBM72) were fused with Umcel9A at the natural terminal position, resulting in significant enhancement of the binding capacity of the chimeric enzymes toward four different insoluble celluloses as compared with that of Umcel9A. Catalytic activity of the chimeric enzymes against insoluble celluloses, including phosphoric acid-swollen cellulose (PASC), alkali-pretreated sugarcane bagasse (ASB), filter paper powder (FPP), and Avicel, was higher than that of Umcel9A, except for Umcel9A-CBM3. In these chimeric enzymes, CBM4-Umcel9A exhibited the highest activity toward the four tested insoluble celluloses and displayed 4.2-, 3.0-, 2.4-, and 6.6-fold enhanced activity toward PASC, ASB, FPP, and Avicel, respectively, when compared with that of Umcel9A. CBM4-Umcel9A also showed highest V (max) and catalytic efficiency (k (cat)/K (M)) against PASC. Construction of chimeric enzymes may have potential applications in biocatalytic processes and provides insight into the evolution of the molecular architecture of catalytic module and CBM in GH9 cellulases.
A newly isolated endo-beta-1,4-xylanase (Xyn10E) from Paenibacillus curdlanolyticus B-6 has a modular structure consisting of a family 22 carbohydrate-binding module (CBM), a glycoside hydrolase (GH) family 10 catalytic domain, two fibronectin type III (Fn3) domains, and a family 3 CBM at the C-terminus. Intact Xyn10E (rXyn10E), CBM22-deleted Xyn10E (X-CBM3), CBM3-deleted Xyn10E (X-CBM22), and GH10 catalytic domain only (X-GH10) were expressed in Escherichia coli. rXyn 10E showed bifunctional degradation activity toward xylan and beta-glucan and also degraded microcrystalline cellulose. Although X-CBM3 and X-GH10 had drastically reduced xylanase and beta-glucanase activities, X-CBM22 mostly retained these activities. Similar K. values were obtained for rXyn 10E and X-CBM3, but k(cat) and k(cat)/K-m values for X-CBM3 and X-GH10 were lower than those for rXyn 10E, suggesting that CBM22 of Xyn10E may contribute to catalytic efficiency. In binding assays, X-CBM3 was still able to bind to 8-glucan, soluble xylan, insoluble xylan, and cellulose through GH10 and CBM3. These results indicate that CBM22 has an important role not only in binding to xylan and 8-glucan but also in feeding both polysaccharides into the neighboring GH10 catalytic domain, rXyn10E showed remarkable synergism with rXyn1 1A, a major xylanase subunit of P. curdlanolyticus B-6, in the degradation of untreated corn stover and sugarcane bagasse; however, the combination of X-CBM3 and rXynl 1A was not synergistic. These results indicate that Xyn10E and Xyn11A act synergistically on lignocellulosic biomass, and CBM22 is essential for efficient degradation of lignocellulosic materials. (C) 2016 Elsevier Inc. All rights reserved.
This study deals with a preliminary investigation of biomass samples' physicochemical, structural composition, and thermal properties to aid the appropriate selection of biomass utilized for pyrolysis operation. The proximate, ultimate, structural composition and thermal analyses were conducted using seven lignocellulose biomass samples obtained in Ajase market, Ajasse Ipo, Kwara State, Nigeria, and Omu-Aran, Kwara State, Nigeria. Results showed that the average moisture contents (MC) ranged from 0.12 to 0.44\%, and volatile matter (VM) ranged from 73.70 to 83.82\%. Fixed carbon (FC) varied from 12.79 to 22.80\%, and Ash contents varied between 01.20 to 5.52\%. Similarly, the average carbon contents ranged from 45.11 to 50.00\%. Hydrogen contents ranged from 5.38 to 6.15\%, nitrogen contents varied between 0.20 to 1.24\%, and oxygen contents from 43.79 to 48.51\%. Also, sulphur contents varied between 0.01 to 0.19\%, while the biomass species' average cellulose, hemicellulose, and lignin contents ranged from 28.34 to 45.80\%, 25.83 to 34.01\%, and 21.96 to 49.63\% respectively. The high percentage of VM, C, H, HHV, ignitability index, cellulose, and hemicellulose content recorded in the biomass samples would enhance devolatilization reactivity, ignitability, and burn gases in the reactor, as well as a good production of hydrocarbons content during the pyrolysis process. Also, the low ash content would prevent harmful chemical deposits in the reactor during the pyrolysis process. It can be deduced that shea butter wood was best suited for biofuel generation, closely followed by sugarcane bagasse and palm kernel shell. At the same time, corn cobs possessed the least properties for the pyrolysis process.
The work optimized the production of xylanases by solid-state cultivation by Trichoderma koningii and Trichoderma pseudokoningii. The xylanases were biochemically characterized, the catalytic potential of enzymatic extracts and their use as an additive in the feeding of ruminants were eval-uated. The higher production of xylanases by T. koningii, approximately 524.3 U g-1 (or 52.43 UmL-1), was obtained for cultivation in a substrate composed of wheat bran and sugarcane bagasse in a 4:1 g ratio, respectively, containing 60\% initial moisture, and kept at 20 degrees C for 120 h. The xylanase used by T. koningii showed excellent activity at pH 4.5 and 50 degrees C and re-mained stable at pH 3.0-9.5 and for 1 hat 45 degrees C. T. pseudokoningii had a higher production of xy-lanase, 721.0 U g-1 (72.10 UmL-1), when grown in wheat bran, with 50\% initial moisture, at 25 degrees C for 96 h. The xylanases produced by T. pseudokoningii showed greater catalytic activity at pH 4.5 and 55 degrees C and were stable at pH 3.0-9.5 and for 1 hat 50 degrees C. The best results of in vitro di-gestibility were obtained in Mombaca grass containing the enzymatic extract of T. koningii, reach-ing a maximum gain of 12\% in digestibility, expressed in dry mass. The chromatographic profile of the products resulting from the enzymatic hydrolysis of xylan indicated the predominant ac-tion of endoxylanases. Additionally, the enzymatic extracts showed reduced cellulolytic activity, which enables its use in cellulose pulp bio-bleaching processes.
India is an economically developing country. Country's development and growth is largely interlinked with iron and steel industry as well as availability of energy and its utilization. Energy sector and iron and steel industry mainly consumes convectional and fossil fuel like coal and gas. Present coal reserves of India will last for about 30-40 years at present consumption rate. Consumption of conventional fuels is not economically feasible and environment friendly. Biomass can be an alternative source of fuel for numerous engineering and scientific applications. The char derived from biomass known as biochar can be utilized in the iron and steel-making processes. It can lessen the coke consumption rate and subsequently reduce pollution as well as cost economics. Utilization of low and lean grade iron ore is need of the hour. Removal of gangue impurities from lean and low-grade iron ore is difficult through convectional beneficiation process. The reduction roasting process can be adopted to counter these challenges. The present study focuses on the reduction behavior of iron ore using three various biochar derived from three biomass, viz; wood dust, sugarcane bagasse and coconut shell. A single factorial Design of Experiment with two levels and three variables was adopted and a first-order regression equation was generated to estimate the degree of reduction. The Student's T-test and Fisher test were performed to validate the regression equation. The obtained results showed that the biochar can be used as a substitute reductant. However, the residence time and temperature play a vital role in the reduction process. The obtained regression equation also validates the effect of residence time and temperature on the reduction process.
Agricultural and soil management practices have been reported to affect alachlor sorption-desorption and degradation rates. Though alachlor has been banned in the E.U. since 2006, it is still used in U.S. corn and soybean production. The objectives of this study were to: (a) assess differences in alachlor sorption due to tillage treatments (chisel plow and ridge tillage) on soils from three midwestern U.S. locations; and (b) determine the effect of various soil amendments on the sorption-desorption and mineralization of alachlor. Soils were amended at a rate of 10\% (w/w) with biochars derived from soybean stover, sugarcane bagasse, and wood chips, as well as the uncharred feedstock materials. Sorption-desorption studies were performed using the batch equilibration method, and alachlor mineralization was evaluated in a 30-day incubation. Tillage management did not affect alachlor sorption to soil across the three sites, despite the fact that the tillage operations were imposed for 4 years (p > 0.05). While the sorption coefficient (K-d) values for alachlor were relatively low in the three unamended soils (K-d = 1.76, 1.73, and 1.15 L.kg(-1) for IL, MN, and PA soils, respectively), biochar amendments increased alachlor sorption between 4x and 33x compared to the unamended soil. The amendments also affected alachlor mineralization such that degradation was slower in both biochar- and raw feedstock-amended soils. Based on these results, biochar additions are expected to affect the availability of alachlor for transport and degradation. Furthermore, this study highlights the larger impact of biochar addition than tillage practices on altering immediate alachlor sorption capacities.
This study investigates ethanol production from simultaneous fermentation and saccharification (SFS) and separated hydrolysis and fermentation (SHS) using enzyme complexes produced by Aspergillus niger strains (ATCC 16404, ATCC 1057, ATCC 9029). The enzyme complexes were produced by solid-state fermentation (SSF) on inexpensive and readily available agroindustrial products: rice byproduct (composed of AFEX-treated rice rust and rice bran), whey and sugarcane bagasse. The ethanol was produced by Saccharomyces cerevisiae Y904 using whey and rice byproduct as the substrate and the enzyme complex produced by A. niger. The best result for solid-state fermentation (40 U/g of dry substrate, A. niger ATCC 16404) was obtained in a 0.5 L rotating drum bioreactor at 40 degrees C filled half filled with solid biomass composed of rice byproduct (86\% wt/wt), whey (12\% wt/wt) and CaCl2 (2.0\% wt/wt). The best result for ethanol fermentation (11.7 g/L of ethanol) was obtained after 12 h of SFS at pH 4.5 and 35 degrees C. A comparative study of ethanol production by Trichoderma reesei CCT 2768 and A. niger ATCC 16404 complexes under the same optimised SFS and SSF conditions was also performed, revealing that ethanol production by the A. niger enzyme complex was 2.25 times higher than that by T. reesei. These findings suggest that the ethanol production using crude enzymatic complexes produced by A. niger and agroindustrial biomass described in this paper is very promising in terms of disposal of the whey produced by cheese-making and other dairy food processing. (C) 2013 Elsevier Ltd. All rights reserved.
The aim of this study was to evaluate the genetic diversity and coefficient of kinship in 50 sugarcane genotypes, in addition to identifying potential parents for obtaining cultivars of energy cane. Diversity analysis was carried out based on the evaluation of morphological and agronomical characteristics. The coefficient of kinship was obtained from information on pedigree. According to analyses carried out, genotypes were separated into two groups. Group G1 consisted of 13 genotypes from the species Saccharum spontaneum and Saccharum robustum. The other 37 genotypes were from back-crosses with Saccharum officinarum, and were allocated to group G2. The genotypes displayed low values for genetic similarity and coefficient of kinship, indicating broad genetic variability in the population. Carrying out crosses involving genotypes from group G1, especially those with a fibre content of over 17\% (IJ76-293, 57NG12, IN84-82, IN84-88, IM76-228 and UM69/001), with genotypes from group G2 which have high stalk yield (RB92579, RB83102, RB047232, RB867515, RB971723, RB937570, RB011941, RB75126, MEX68-200, Co62175 and CP691052), should be explored, with the aim of developing energy cane cultivars. Analyses of diversity and of the coefficient of kinship made it possible to identify two heterotic groups. Moreover, it was possible to identify two potential parent groups for obtaining energy cane cultivars. Genetic distances which are based on both morpho-agronomical data and on pedigree, should be used in a complementary way, with a view to having more information when choosing the best parents.
This study carried out the screening of wastes from Amazon plants to produce hydrolysates with a high monosaccharides content for ethanol production. Initially, we hydrolyzed (diluted acid) Amazon wastes (peel from the fruit of Astrocaryum aculeatum Meyer, peel from the fruit of Bactris gasipaes Kunth, straw obtained from endocarp of the fruit of Euterpe oleracea Mart., peel from the fruit of Theobroma grandiflorum Schumann and peel from the root of Manihot esculenta Crant) to obtain hydrolysates with the high content of fermentable sugars. Then, we investigated by 2(3) factorial design the influence of the factors: a) hydrolysis time (min); b) H2SO4-to-waste ratio (g/g) and c) solid-to-liquid ratio (g/mL) in the variables reducing sugars and furans. The hydrolysis of the peel of the fruit of Bactris gasipaes resulted in the highest concentration of reducing sugars (23.7 g/L). After detoxification and concentration process, the Bactris gasipaes hydrolysate results in 96.7 g/L of reducing sugars largely fermentable (90\%) by Saccharomyces cerevisiae PE-2. The experimental design demonstrated that the factors H2SO4-to-waste ratio (g/g) and solid-to-liquid ratio (g/mL) were the most significant affecting the final content of reducing sugars and furans in the hydrolysate of the peel of Bactris gasipaes. Hydrolysis time of 4.4 min, H2SO4-to-waste ratio of 0.63 g/g, and the solid-to-liquid ratio of 0.17 g/mL resulted in the concentration of reducing sugars of 49 g/L. This study shows the potential of peels from the fruit of Bactris gasipaes to produce ethanol.
In this study, an effective pretreatment of dilute NaOH-soaked chestnut shell (CNS) with glycerol-HClO4-water (88.8:1.2:10, w/w/w) media at 130 A degrees C for 30 min was successfully demonstrated. Results revealed that the combination pretreatment removed 66.0 \% of lignin and 73.7 \% of hemicellulose in untreated CNS. The changes in the structural features (crystallinity, morphology, and porosity) of the solid residue of CNS were characterized with Fourier transform infrared spectroscopy, fluorescent microscope, scanning electron microscopy, and X-ray diffraction. Biotransformation of glycerol-HClO4-water pretreated-NaOH-soaked CNS (50 g/L) with a cocktail of enzymes for 72 h, the reducing sugars and glucose were 39.7 and 33.4 g/L, respectively. Moreover, the recovered hydrolyzates containing 20 g/L glucose had no inhibitory effects on the ethanol-fermenting microorganism, and the ethanol production was 0.45 g/g glucose within 48 h. In conclusion, this combination pretreatment shows promise as pretreatment solvent for wheat straw, although the in-depth exploration of this subject is needed.
Immobilized biocatalysts design has the potential to efficiently produce valuable bioproducts from lignocellulosic biomass. Among them, the carrier-free immobilization through the cross-linked enzyme aggregates technology is a simple and low-cost alternative. A two steps statistical approach was utilized to evaluate the synthesis of a cross-linked enzyme aggregate from a xylanolytic preparation, which was produced by Cohnella sp. AR92 grown in a peptone-based culture medium. The resulting immobilized biocatalyst, Xyl-CLEA, was significate more stable (25 to 45\%) towards temperatures up to 50 degrees C with respect to the free enzyme, and retained over 50\% of its initial activity after 5 consecutive cycles of reuse. By means of infrared spectroscopy and electron microscopy, the Xyl-CLEA showed architectural features described as signature of type I and type II of protein aggregates. These, were the result of the simultaneous aggregation of a multiplicity of proteins from the crude enzymatic extract. The enzymatic activity was assessed using alkali pretreated sugar cane bagasse as substrate. Whereas the free enzymatic preparation released xylose as the main product, the immobilized xylanase produced xylooligosaccharides, thus showing that the immobilization procedure modified the potential application of the extracellular xylanase from Conhella sp. AR92. (C) 2018 Elsevier B.V. All rights reserved.
Current study employs solid residues from the processing industry of the cassava (Manihot esculenta Crantz) (bark, bagasse and bark + bagasse) as natural adsorbents for the removal of metal ions Cu(II) and Zn(II) from contaminated water. The first stage comprised surface morphological characterization (SEM), determination of functional groups (IR), point of zero charge and the composition of naturally existent minerals in the biomass. Further, tests were carried out to evaluate the sorption process by kinetic, equilibrium and thermodynamic studies. The adsorbents showed a surface with favorable adsorption characteristics, with adsorption sites possibly derived from lignin, cellulose and hemicellulose. The dynamic equilibrium time for adsorption was 60 min. Results followed pseudo-second-order, Langmuir and Dubinin-Radushkevich models, suggesting a chemisorption monolayer. The thermodynamic parameters suggested that the biosorption process of Cu and Zn was endothermic, spontaneous or independent according to conditions. Results showed that the studied materials were potential biosorbents in the decontamination of water contaminated by Cu(II) and Zn(II). Thus, the above practice complements the final stages of the cassava production chain of cassava, with a new disposal of solid residues from the cassava agroindustry activity.
Conversion of broad-spectrum organic waste into carbonaceous biochar has gained enormous interest in past few years. The present study aims to characterize feedstock (FS), i.e. bagasse (Bg), bamboo (Bm) and biochar (BC), i.e. baggase biochar (BBg), bamboo biochar (BBm) and tyre biochar (Ty). Significant changes in elemental composition, atomic ratio, proximate analyses, mineral content and heavy metal content were observed which was well supported by Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) analysis. Impregnation with ferric hydroxide was done, and resultant modified biochars (MBC), i.e. iron-impregnated baggase biochar (FeBBg), iron-impregnated bamboo biochar (FeBBm) and iron-impregnated tyre biochar (FeTy), along feedstock and biochar were used for PO4 (3-), Pb, Hg and Cu adsorption. In general, BBg, FeBBg, BBm, FeBBm, Ty and FeTy were found to adsorb PO4 (3-), Pb, Hg and Cu better than Bg and Bm, except in few cases. Results from adsorption experiments were fitted into Langmuir, Freundlich and Temkin models of isotherms and pseudo-first-order, pseudo-second-order and Elovich models of kinetics. Result of batch study adsorption revealed that maximum adsorption of PO4 (3-), Pb, Hg and Cu was done by FeBBg (adsorption mechanism explained by Freundlich model), FeTy (Temkin model), Ty (Langmuir model) and BBm (Langmuir model) respectively. According to R (2) values, pseudo-first-order reaction was well suited to PO4 (3-), Pb, Hg and Cu adsorption. The optimum pH for maximum adsorption was observed to be 7.4 for PO4 (3-), 5 for Cu and 6 for Pb and Hg respectively.
The durability of concrete against penetration of chloride ions is one of the most important factors that can affect the serviceability of structures. Many tests can measure or predict the durability of concrete structures during their lifespan. Recently, many researchers have tried to provide different relationships and correlations between durability tests. The rapid chloride migration test, the electrical resistivity test and the water absorption test are some of the common and practical tests that may be used for studying the durability and permeability of cementitious materials. Providing an empirical correlation among these tests could yield the opportunity to estimate the durability parameters. This study presents relationships between durability tests and their correlations with the compressive strength in mortars containing rice husk ash, nanosilica and sugar cane bagasse ash. The empirical correlation between electrical resistivity and the migration coefficient followed the Nernst-Einstein equation. A strong linear correlation between electrical resistivity and compressive strength of binary mixtures was found, whereas a weak correlation was found for ternary mixtures. Moreover, a strong power correlation between electrical resistivity and capillary absorption of mortars was found.
Knowledge about the proper management of not-burned sugar cane is still limited, particularly regarding nitrogen fertilization. A field experiment was carried out to evaluate sugar cane yield, the balance of N-15 fertilizers in the soil-plant-residue system and ammonia loss by volatilization in sugarcane ratoon crop without straw burning prior to mechanical harvesting, comparing different locations of surface-applied nitrogen fertilizers. The sugar cane variety SP81-3250. Treatments were arranged in a complete randomized blocks, with four replicates. The treatments consisted of four N fertilizer sources: ammonium nitrate (AN), ammonium sulfate (AS), urea and Uran, applied over the residues in two ways: over the entire area or side dressed on both sides of the ratoon crop line, at a rate of 70 kg N hat. The plots treated with AS and urea were divided in microplots with N-15 labeled fertilizers. The ammonia losses by volatilization were higher for urea and uran, which contain amidic nitrogen, especially when sidedressed in bands. Ammonia losses by volatilization caused a reduction in yield, whereas the location of the fertilizer-N had no influence on the sugar cane yield. Independent of the nitrogen source location, the recovery of N-15 from AS in sugar cane was twice as high as from urea. The nitrogen recovered in the soil-plant-trash system was 74 and 55 \% of the N applied as AS and urea, respectively.
Energy consumption in rural areas and the increasing demand for liquid fuels in Brazil has stimulated the development of alternatives for fuels production, including ethanol. The potential of small-scale ethanol production (SSEP) e up to five thousand litres daily e can help to meet this demand and contribute byproducts to animal feed. This study aims to assess the economic feasibility and environmental impacts of ethanol production at a small-scale distillery with a production capacity of 30 L h(-1) of hydrous ethanol fuel (HEF). Regarding cost, three cases were analyzed in which the minimum, average and maximum raw material prices were assessed. The cost of HEF for these cases was US\$ 0.68, 0.92 and 1.16 per litre, respectively, highlighting the cost of the raw materials, which can contribute up to 69\% of the total cost. Life cycle Assessment (LCA) shows that agricultural stage is responsible for higher environmental impact in 7 of 11 categories, requiring special attention to minimize potential damage. SSEP has positive energy balance (1.97) only considering bagasse silage as byproduct or replacing firewood by bagasse to generate process heat (7.39). This study demonstrates that without the support of policies that provide economic incentives for HEF production, the small-scale production of HEF will have a secondary role in supplying HEF to meet the demand for liquid fuels in Brazil. (C) 2016 Elsevier Ltd. All rights reserved.
A novel bacterial isolate with polysaccharides degrading activity was identified as Paenibacillus sp., and named Paenibacillus sp. A59. Even though it is a strict mesophile, optimal xylanase activity of the crude enzymatic extract was achieved between 50 degrees C and 70 degrees C and more than 60\% of the activity was retained after incubation for 48 h at 50 degrees C, indicating thermotolerance of the enzymes involved. The extract was also active on pre-treated sugarcane residue (SCR) and wheat straw, releasing xylobiose and xylose as the main products, therefore confirming its predominantly xylanolytic activity. By zymograms and mass spectrometry of crude enzymatic extracts of xylan or SCR cultures, a 32 kDa GH10 beta- 1,4- endoxylanase with xylanase and no CMCase activity was identified. We named this enzyme XynA and it was the only xylanase identified under both conditions assayed, suggesting that it is a good candidate for recombinant expression and evaluation in hemicelluloses deconstruction applications. Also, a protein with two S-layer homology domains (SLH) and a large uncharacterized C-terminal domain as well as an ABC substrate binding protein were identified in crude extracts of SCR cultures. We propose that Paenibacillus sp. A59 uses a system similar to anaerobic and other Gram positive bacteria, with SLH-domain proteins anchoring polysaccharide-degrading enzymes close to the membrane and the substrate binding protein assisting translocation of simple sugars to the cell interior. (C) 2016 Elsevier GmbH. All rights reserved.
Researchers are pursuing strategies to utilize the soil's recalcitrant phosphorus (P) pool as rock phosphate reserves are depleting rapidly. Phosphate-solubilizing bacteria (PSB) and silicon (Si)-rich agro-wastes (as Si sources) were investigated with the aim of searching for eco-friendly and cost-effective strategies to solubilize the recalcitrant soil P in agriculture. A 90-day incubation experiment was carried out in an Inceptisol at 25 degrees C with field capacity soil moisture. Three factors, viz., Si-rich agro-wastes (3 levels: sugarcane bagasse ash, rice husk ash, and corn cob ash), PSB (2 levels: no PSB with PSB); and Si doses {[
Mycelium-based biofoam has the potential to become an alternative to petroleum-polymeric based-foam by utilising fungal mycelium and lignocellulosic material as the matrix and substrate, respectively. The lignocellulosic materials, which were rice husk, sawdust, and sugarcane bagasse, which is crucial for the production of biofoam, were tested as a substrate for Pleurotus ostreatus mycelium growth during the screening procedure. Three growth factors were varied during mycelium-based biofoam production: incubation temperature, spawn loading, and moisture content. In this study, rice husk was the ideal substrate in the production of mycelium biofoam compared to other fungi. The inhibition of P. ostreatus mycelium growth at 30 degrees C incubation temperature was due to decay and contamination. On the other hand, by varying the growth factor of mycelium biofoam on rice husk, the optimum dry density of mycelium-biofoam was observed at 50\% (w/w) moisture content (1.07 g/cm(3)), while the optimum compressive strength was observed at 40\% (w/w) spawn loading (1.350 MPa). These results showed that varying the growth factor could influence the mechanical behaviour of the material. The morphology of the biofoam was also observed through a scanning electron microscope. Short and highly entangled tube-like structures and compact filaments forming a material were seen, responsible for the lightness characteristic of the material. The functional group of the biofoam was also determined using a Fourier transform infrared spectrophotometer. A new band of proteins and lipids was detected at 1633 cm(-1) and 3280 cm(-1) in the biofoam. It clearly shows the chemical nature of feeding substrate responsible for the changes of material spectra. Therefore, this study highlighted that the biodegradable mycelium biofoam of P. ostreatus using rice husk as a substrate is a promising alternative to polymeric foam.
Green nanocomposites of Fe-0@chitosan/cellulose (Fe-0@CH/CS) were synthesized utilizing a green extract of Khaya senegalensis leaves and sugarcane bagasse as a cellulose precursor. The composite was evaluated as an effective carrier for ibuprofen drug (IBF) considering its release and loading properties. The Fe-0@CH/CS composite has a significant IBF loading capacity of 553 mg g(-1), and the loading behavior can be directed by the values of the experimental variables. The loading of IBF into Fe-0@CH/CS is in agreement with the classic Langmuir isotherm (R-2 > 0.95) and pseudo-first-order kinetic (R-2 > 0.97). This displays homogeneity, physisorption, and monolayer loading of IBF into Fe-0@CH/CS. Based on the findings of the monolayer model with one energy as an advanced isotherm model, the Fe-0@CH/CS structure has 252.6 mg g(-1) active receptor density and each receptor is occupied by two or three IBF ions (n = 2.18) via a multi-molecular mechanism. The determined IBF loading energy (4.81 kJ mol(-1)) demonstrates the physical loading of the drug by van der Waals forces and/or hydrogen bonding. The Fe-0@CH/CS structure has significant release profiles as a carrier for IBF, which continued up to 260 h (gastric buffer) and 180 h (intestinal buffer). The studied release kinetics and the obtained diffusion exponent (0.58 (pH 1.2) and 0.48 (pH 7.4)) reflect the release of IBF from Fe-0@CH/CS by complex diffusion and erosion mechanisms. The cytotoxicity tests declared the safety and biocompatibility of both Fe-0@CH/CS and IBF-loaded Fe-0@CH/CS in human bronchial epithelial cells.
This research was conducted to compare the accuracy of two mathematical models to predict calcium (Ca) metabolism in sheep supplemented with different Ca sources. Twenty Brazilian male sheep averaging 7 to 8 months of age were fed a basal diet containing corn, soybean meal, hydrolyzed sugarcane bagasse, urea, mono-ammonium phosphate. mineral mixture and one of the following Ca sources: limestone (LM), alfalfa hay (AH), dicalcium phosphate (DP), oyster shell meal (SM), and citrus pulp (CP). On day 22 each animal received an intravenous injection of 7.7 MBq of radio-calcium (Ca-45) followed by collection of blood, feces, and urine every 24 h for 7 days. Total Ca and radioactivity were measured in all samples. At the end of the collection period, animals were slaughtered and samples of liver, heart, kidney, muscles and 12(th) rib were taken for analysis. Calcium metabolism was evaluated by the models proposed by Vitti et al. (2000) and Fernandez (1995). A completely randomized design was used and means were compared by the Duncan test. No significant differences were observed for Ca intake among treatments. However, total fecal excretion of Ca differed and was lowest in animals fed LM. Calcium balance was negative in sheep receiving AH and CP because Ca absorption might have been compromised by the high contents of pectin and oxalate in these two supplements, respectively. Flows of Ca between the central pool and the digestive tract showed the greatest absorption of Ca on animals fed LM. Diets supplemented with LM, DP, and SM had highest Ca availability with values of 65.38, 34.12 and 32.43\%, respectively. The models differed in the predictions of Ca flows among blood, bone and soft tissues but showed similar values for Ca balance in the different compartments. These discrepant results may be explained by structural difference between models.
This research was conducted to investigate the effect of live and inactive sugarcane yeast on beef cattle voluntary intake, apparent digestibility of nutrients, ruminal pH, volatile fatty acids (VFA) concentrations, and ruminal ammonia. Five rumen-cannulated Nellore heifers were distributed in a 5x5 Latin square design, with five experimental periods of 15 days, with seven days for adaptation to the additives and the remaining days for data records and sampling. Total mixed ration (TMR) was composed by corn silage (20\%) and concentrate (80\%) based on corn and soybean meal. Five treatments were evaluated: without additive use (negative control; NC); chemical buffer addition - 0.71\% in concentrate DM of sodium bicarbonate and 0.18\% of magnesium oxide (positive control, PC); 10 g/day live yeast (LY); 15 g/day of inactive yeast (IY15); and 30 g/day of inactive yeast (IY30). Sugarcane yeasts were directly infused in rumen immediately after morning and afternoon feed supply. Feed additives did not affect voluntary intake, nutrient digestibility, and sorting behavior of animals. However, heifers from all treatments presented preferential intake of fibrous fraction of diet, especially those from NC and IY15. Nitrogen balance, VFA concentrations, and blood parameters were not influenced as well. Sodium bicarbonate and magnesium oxide led to greater ruminal pH than yeast, and IY15 presented greater pH than IY30. Ruminal ammonia was increased by the use of additives. Active and inactive yeasts are not recommended as feed additives for bovines fed diets with 80\% of concentrate since it allows animals to select fibrous particles from TMR, and no representative gain in ruminal parameters and digestibilities are guaranteed.
The acid pretreated sweet sorghum bagasse was mixed with the fermentable juice for ethanol production by simultaneous saccharification and juice co-fermentation (SSJcF). The effect of sulfuric acid concentration on ethanol production was evaluated. Two-phase of fermentation was occurred distinctly during the process. Under the optimized conditions (2\% of sulfuric acid and 20 FPU/g of cellulase added at 0 h), 120.41 +/- 0.4 g/L of ethanol was achieved after 216 h of inoculation, with ethanol yield of 67.75 g/kg of the fresh sweet sorghum stalk (FSSS) that contained water and was rich in monosaccharide and cellulosic biomass. This study provided a potential way for high titer ethanol production by SSJcF using FFFS, which is benefited to the downstream ethanol separation processes. (C) 2018 Elsevier Ltd. All rights reserved.
Background Xylitol is a commercially important chemical with multiple applications in the food and pharmaceutical industries. According to the US Department of Energy, xylitol is one of the top twelve platform chemicals that can be produced from biomass. The chemical method for xylitol synthesis is however, expensive and energy intensive. In contrast, the biological route using microbial cell factories offers a potential cost-effective alternative process. The bioprocess occurs under ambient conditions and makes use of biocatalysts and biomass which can be sourced from renewable carbon originating from a variety of cheap waste feedstocks. Result In this study, biotransformation of xylose to xylitol was investigated using Yarrowia lipolytica, an oleaginous yeast which was firstly grown on a glycerol/glucose for screening of co-substrate, followed by media optimisation in shake flask, scale up in bioreactor and downstream processing of xylitol. A two-step medium optimization was employed using central composite design and artificial neural network coupled with genetic algorithm. The yeast amassed a concentration of 53.2 g/L xylitol using pure glycerol (PG) and xylose with a bioconversion yield of 0.97 g/g. Similar results were obtained when PG was substituted with crude glycerol (CG) from the biodiesel industry (titer: 50.5 g/L; yield: 0.92 g/g). Even when xylose from sugarcane bagasse hydrolysate was used as opposed to pure xylose, a xylitol yield of 0.54 g/g was achieved. Xylitol was successfully crystallized from PG/xylose and CG/xylose fermentation broths with a recovery of 39.5 and 35.3\%, respectively. Conclusion To the best of the author's knowledge, this study demonstrates for the first time the potential of using Y. lipolytica as a microbial cell factory for xylitol synthesis from inexpensive feedstocks. The results obtained are competitive with other xylitol producing organisms.
Forestry and agricultural industries constitute highly relevant economic activities globally. They generate large amounts of residues rich in lignocellulose that have the potential to be valorized and used in different industrial processes. Producing renewable fuels and high-value-added compounds from lignocellulosic biomass is a key aspect of sustainable strategies and is central to the biorefinery concept. In this study, the use of biomass-derived monosaccharides for the enzymatic synthesis of sugar fatty acid esters (SFAEs) with antimicrobial activity was investigated to valorize these agro-industrial residues. With the aim to evaluate if lignocellulosic monosaccharides could be substrates for the synthesis of SFAEs, d-xylose, l-arabinose, and d-glucose, lauroyl and stearoyl monoesters were synthetized by transesterification reactions catalyzed by Lipozyme RM IM as biocatalyst. The reactions were performed using commercial d-xylose, l-arabinose, and d-glucose separately as substrates, and a 74:13:13 mixture of these sugars. The proportion of monosaccharides in the latter mixture corresponds to the composition found in hemicellulose from sugarcane bagasse and switchgrass, as previously described in the literature. Products were characterized using nuclear magnetic resonance (NMR) spectroscopy and showed that only the primary hydroxyl group of these monosaccharides is involved in the esterification reaction. Antimicrobial activity assay using several microorganisms showed that 5-O-lauroyl-d-xylofuranose and 5-O-lauroyl-l-arabinofuranose have the ability to inhibit the growth of Gram-positive bacteria separately and in the products mix. Furthermore, 5-O-lauroyl-l-arabinofuranose was the only product that exhibited activity against Candida albicans yeast, and the four tested filamentous fungi. These results suggest that sugar fatty acid esters obtained from sustainable and renewable resources and produced by green methods are promising antimicrobial agents.
The aim of this study was to determine the airway exposure of sugar and papermaking factory workers to aflatoxin B1 (AFB1) and to explore the potential association between AFB1 airway exposure and the risk of hepatocellular carcinoma (HCC) in a case-control study. Dust samples were collected from the sugarcane bagasse warehouse, and presser and paper production workshops. Blood samples were collected from 181 workshop employees and 203 controls who worked outside the workshop. AFB1 albumin adducts were detected using a double antibody sandwich enzyme-linked immunosorbent assay (ELISA). To explore the association between AFB1 airway exposure and the risk of HCC, the medical records of 68 HCC patients who worked in a sugar and papermaking factory between January 1994 and December 2013 were analyzed. A questionnaire was used to collect information from 150 healthy controls who worked for the same company and lived near the factory. AFB1 was detected in the dust samples, but could not be detected in any of the rice samples. An analysis of serum samples revealed serum AFB1 albumin adducts in 102 (56.35 \%) of the study participants. However, in the control group, only 12 (5.9 \%) individuals had detectable levels of AFB1 albumin adducts. Those with airway exposure to Aspergillus flavus-contaminated dust had an elevated risk of HCC compared to those without exposure (odds ratio, 5.24; 95 \% confidence interval, 2.77-9.88; P-0.00). The findings of this study indicate that occupational AFB1 airway exposure might be associated with the risk of AFB1-related HCC among the population that was used in this study. Intervention programs aimed at reducing exposure to inhalational AFB1 are needed urgently. Additional suitably designed, multicenter, prospective studies using large samples are needed to further confirm the results.
Lignocellulosic biomass is one of the most abundant raw materials in the world, and it is mainly composed of carbohydrate polymers (cellulose and hemicellulose) and lignin. Its applications vary from the production of pulp and paper, to the most recent plant-based bioethanol production, which has challenge due to low hydrolysis conversion rates by the inherit recalcitrance of biomass. The biomass is naturally resistant due the high complexity in the component organization and interaction in the cell wall. The application of pretreatment technologies is one of the most used strategies to overcome biomass recalcitrance. These techniques often require a catalyst to modify the lignocellulosic structure which can be acids, alkaline compounds, ionic solutions, organic solvents, and even pressurized steam among others. The type of catalyst dictates the name of the pretreatment involved. This work presents an overview of these strategies, along with some recent contributions from the scientific community to improve biomass conversion technologies. The discussion is focused on the key factors related to the recalcitrance and conversion process, as well as the composition and physicochemical properties.
The quality of the carbon used as bulking agent in the composting process directly affects the dynamics of the waste degradation, which is governed by an active and diversified microbiota. The monitoring of the basal respiration and enzymatic activities during the composting of broiler agro-industrial wastes with different carbon sources as bulking agents was the aim of this study. The microbiological activities were more intense in the thermophilic phase of the process. The dynamics of the enzymatic activities were affected by the different carbon sources used as bulking agent in the composition of the windrows. When the milled sugarcane bagasse was used as carbon source, the windrow presented the highest amount of P in its constitution and presented, in the evaluation averages, a greater intensity of the alkaline phosphatase enzyme (842 mu g g(-1) h(-1) p-nitrophenol compost); the highest intensities of beta-glucosidase and cellulase enzymes were observed when fresh and ground napier grass was used as the main source of carbon (6.1 mu mol g(-1) h(-1) p-nitrophenol compost and 35.2 umol g(-1) 16h(-1) glucose compost, respectively); the highest intensity of the urease enzyme was also observed in the windrow where napier grass was used as the main carbon source and bulking agent (205,890 umol g(-1) 2 h(-1) N-NH4+ compost). It can be concluded that napier grass when used as the main source of carbon and bulking agent in the composting of the wastes from broiler chicken production chain promotes greater intensity of most of the enzymatic activities of interest. The enzymatic activity of urease presented the highest values due to the high nitrogen content of the composted wastes.
In this investigation, an attempt has been made to evaluate the performance of a novel Semifluidized bed adsorption column for the removal of divalent heavy metal ions from synthetic wastewater. Low cost low density adsorbent has been synthesized from Sugarcane bagasse based biochar and Na-Alginate. The biochar has specific surface area of 391.42 m(2)/g and it's composite has 200.14 m(2)/g respectively. Major operating parameters for the system were adsorbent bed height, initial solute concentration and feed flow rate. The optimum condition of the process for maximum percentage removal of metal ions was analysed by Response Surface Methodology technique. The satisfactory values of correlation coefficients ensure the suitability of the model from process optimization. The optimum conditions for Zn2+, Cu2+ and Ni2+ were of same values having initial adsorbent bed height 12.97 cm, initial solute concentration 14.05 mg/L and feed flow rate of 2.81 LPM(Liter Per Minute) and maximum percentage removal were found to be 87.56 \%, 88.89 \% and 84.31 \% respectively. A real-time dynamic mass transfer model based on solid-liquid mass balance has also been developed and validated with all the experimental data. Solid-liquid interphase mass transfer coefficient along with the axial dispersion coefficient for individually packed and a fluidized section of bed was also estimated from the developed model. The axial dispersion coefficient was calculated as 5.1 +/- 0.3 x 10(-11) m(2)/s for packed section and 4.8 +/- 0.3 x 10(-6) m(2)/s for fluidized section. Mass transfer coefficient for Zn2+, Cu2+ and Ni2+ were 1.11-1.21 x 10(-4) m/s, 1.31-1.371 x 10(-4) m/s 1.09-1.18 x 10(-4) m/s under specific bed operating conditions.
Biodiesel is produced through the process of transesterification of different edible and non-edible oils and animal fats. The process takes place either in the presence of a homogeneous or heterogeneous catalyst. A suitable catalyst is selected based on the amount of free fatty acid (FFA) content present in the oil. The major difference between homogeneous and heterogeneous catalysts is that the homogeneous catalysts are insensitive to the amount of free fatty acids present in the oil. Also, homogeneous catalysts are toxic, highly flammable, and corrosive. Besides, the use of homogeneous catalysts produces soaps as a by-product and a bulk of wastewater which requires additional pretreatment methods and expenses for proper disposal. The research on the biodiesel synthesis in the presence of heterogeneous catalysts (carbon-based catalysts) is continuously studied to achieve a suitable process to produce biodiesel and to improve fuel quality on an industrial scale. Heterogeneous catalysts have great significance in the biodiesel production because of their simple and less expensive manufacturing process, ease of separation, and high reusability. They can be prepared easily by functionalizing the carbon surface with acid or base. Carbon-based catalysts have a high surface area and porosity that can enhance the rate of the esterification/transesterification process. Also, solid acid catalysts can convert the low-quality feedstocks to biodiesel in the presence of active acidic sites. Besides, carbon-based catalysts can be produced through waste e.g. sugarcane bagasse and their use make the production of biodiesel ``Greener{''
Lignocellulosic biomass is an important source of renewable energy and a potential replacement for fossil fuels. In this work, the X-ray fluorescence (XRF) method was used to analyze the elemental composition of raw and pretreated lignocellulosic biomass of cassava peels, corn cobs, rice husks, sugarcane bagasse, yam peels, and mixtures of cassava peels and yam peels, corn cobs and rice husks and all five biomass samples combined. The influence of particle size on elemental properties was investigated by screening the selected biomass into two size fractions, of an average of 300 and 435 mu m, respectively. The total concentration of Mg, Al, Si, P, S, Cl, Ca, Ti, Cr, Mn, Fe, Co, Cu, Zn, Sn, Ni, Br, Mo, Ba, Hg, and Pb were determined for each of the biomass samples before and after the different pretreatments adopted in this study. From the results of the analysis, there was a significant reduction in the concentration of calcium in all the analyzed biomass after the alkaline pretreatment with rice husks biomass having the lowest concentration of 66 ppm after the alkaline pretreatment. The sulfur content of the acid pretreated biomass increased considerably which is likely due to the sulfuric acid used for the acid pretreatment. The fact that a mixture of biomass feedstock affects the properties of the biomass after pretreatment was validated in the mixed biomass of cassava peels and yam peels biomass as an example. The concentration of Mg in the mixed biomass was 1441 ppm but was 200 ppm and 353 ppm in individual cassava peels and yam peels respectively. The results of this study demonstrated that pretreated mixtures of biomass have varied elemental compositions, which could be an important factor affecting downstream processes, especially if a hybrid feedstock is used in a large-scale application.
Four kinds of prepared plant. based porous carbon materials, including sugarcane bagasse carbon (SBC), bamboo leaf carbon (BLC), rice husk carbon (RHC), bamboo stalk carbon (BSC), as well as purchased carbon materials including, coconut shell charcoal (CSC), nut shell carbon (NSC), carbon nanotubes (CNTs), expansible graphite (EG), were respectively used in flame retardant epoxy resin ( EP) with ammonium polyphosphate (APP). The influences of specific surface area, surface activity and morphology of carbon materials on combustion performances and thermal decomposition of flame retardant EP were investigated. The studies by physical adsorption (BET method), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy indicated that all the carbon materials were micron. size dispersed in EP, and BSC had higher specific surface area (2063 m(2)/g) and larger contents of surface active groups such as C-C, C-O-, C= O and COO- than others carbon materials. Meanwhile, the respective addition of BSC (0.8 wt\%) and CNTs (0.8 wt\%) in EP/APP (3.1 wt\%) increased the LOI from 24.6\% to 27.3\% and 27.6\%, resulted in V-1 rate in UL 94 test, and decreased the peak heat release rate by 27\% and 28\% from the cone calorimeter test (Cone), compared to EP/ APP. The results show that the synergic effects mainly depend on the morphology; particle shaped carbon materials with the larger specific surface area, O/C ratio and higher active group contents have excellent flame retardancy. Moreover, thermo. gravimetric analysis (TGA), confocal Raman spectroscopy (CRS) and XPS study confirmed that carbon materials can improve the initial pyrolysis temperature and increase the residual char value of EP/APP. The large specific surface area and high surface activity as well as tubulose morphology not only increased the residual char value, promoted the formation of graphite. like char but also improved the pyro. oxidation of char.
The overall stability of Candida rugosa lipase (CRL) was improved via immobilization onto low-cost eco-friendly carriers (agroindustrial wastes) followed by using spouted bed dryer or spray dryer. Lipase covalently immobilized on glutaraldehyde-activated rice husk proved the greatest performance, retaining 94.1\% of the initial activity, followed by sugarcane bagasse (90.3\%) and green coconut fiber (89.3\%). On the other hand, the enzyme activity retention of CRL-lipase bioencapsulated in magnetic chitosan treated with glutaraldehyde or sodium tripolyphosphate ranged from 73.6\% to 84.6\%. The dried product moisture content, and water activities ranged from 4.1\% and 6.5\% and from 0.2 to 0.35, respectively. After storage for six months at 5 degrees C, the immobilized enzyme systems retained at least 70.0\% of its initial activity (vs 18.3\% retained activity for the free lipase). After ten reuse cycles, enzyme immobilized onto lignocellulosic carriers retained on average 72.7\% of its initial activity. The thermostability of all immobilized derivatives was significantly improved and lipase immobilized onto rice husk showed a stabilization factor of 20.44 at 80 degrees C. The kinetic data showed that the CRL-lipase suffered alterations in catalytic behavior after the immobilization/drying, mainly a slight decrease in affinity to the substrate (up arrow KM). Among all the assessed immobilized lipase for aroma synthesis the rice husk immobilized lipase displayed the best result towards the production of isoamyl caprylate (62.40 g.L-1). In conclusion, this report reinforces the urgent need for the economic development of eco-sustainable immobilized biocatalysts to boost the use of enzymatic technology on industrial scale, and the feasibility of the association of immobilization and drying processes to improve the enzyme-quality features. (c) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.
Herein, a novel route for the production of renewable hydrocarbon jet fuels from the biomass-derived platform chemicals furfural and 2,3-butanediol (BD) was developed. Carbonaceous solid acids bearing -SO3H groups were prepared from biomass or its isolated polymeric components to catalyze the dehydration of BD to methyl ethyl ketone (MEK) in the liquid phase at low temperatures (<170 degrees C). Lignocellulose, cellulose, and lignin were more suitable feedstocks than xylan to prepare cabonaceous solid acids for well introducing -SO3H groups into carbon carriers with good acidity. The highest MEK yield of 57.6\% with 79.1\% BD conversion and 72.8\% MEK selectivity was obtained when sugarcane bagasse solid acid with p-toluenesulfonic acid (PTSA) was used as the catalyst. However, the main side product in the dehydration process was cyclic hydrophobic ketal (CHK), formed by the condensation of BD and MEK, and it could be easily re-converted to BD and MEK via acid catalysis. The C9/C14 precursors were obtained by carbon chain extension via aldol condensation of furfural and MEK under alkaline conditions. The product profile could be easily controlled by adjusting the reaction variables, particularly the ratio of furfural to MEK, as well as the solvent system to maximize the yield of the desired C9/C14 precursors and minimize the formation of heavier condensation products. Under the optimal reaction conditions, nearly 100\% conversion of furfural with a C9/C14 yield of 99.8\% was obtained. Hydrodeoxygenation of the precursors resulted in the formation of hydrocarbon fuels, with C1-C4, C5-C8, and C9-C14 alkane products obtained in the yields of 15.4\%, 7.9\%, and 73\%, respectively. This process showed a theoretical exergy efficiency similar to that of the bioethanol process and higher than that of the biobutanol process.
Toxicity induced by heavy metals is a major concern inagricultureas it decreases crops' growth and yield and leads to the deteriorationof food quality. Recently, activated carbon has been identified asa possible solution. It can potentially improve crop nutrition andimmobilize heavy metals in soil. That is why a glasshouse trial wasconducted to investigate the effects of sugarcane bagasse-derivedbiochar on spinach growth and the availability of cadmium (Cd) andchromium (Cr) in artificially contaminated soil. The soil was placedin pots and contaminated with Cd and Cr at a rate of 10 mg kg(-1). Biochar was added to the soil at concentrationsof 0 (control), 0 (contaminated control), 100, 150, and 200 g, and10-day-old nursery spinach plants were transplanted to the pots. Theresults showed that applying 200 g of biochar significantly increasedshoot weight (235 g), soil pH, electrical conductivity, and organicmatter. The highest levels of Cd (27.71 mg kg(-1))and Cr (20.44 mg kg(-1)) were observed in the contaminatedcontrol pots, while the lowest levels of Cd (16.80 mg kg(-1)) and Cr (9.80 mg kg(-1)) were found in pots treatedwith 200 g of biochar (2\%). Similarly, the highest levels of Cd (35.80mg kg(-1)) and Cr (40.24 mg kg(-1)) in the roots were found in the contaminated control pots, whilethe lowest levels of Cd (19.26 mg kg(-1)) and Cr (21.34mg kg(-1)) were observed in pots treated with 200g of biochar. Biochar application at a rate of 2\% can immobilize Cdand Cr in the soil and improve chlorophyll contents, carotenoids,photosynthetic rate, transpiration rate, and stomatal conductancein spinach in Cd- and Cr-contaminated soils. Further long-term fieldstudies will be necessary to determine the feasibility of applyingbiochar as an organic amendment for enhancing spinach growth and reducingCd and Cr bioavailability in contaminated soil.
Biochar is a low-cost and environmentally friendly amendment with strong ability for adsorption of mercury (Hg) from aqueous solutions, contaminated soils, and sediments. In the present study, six biochars were prepared from the pyrolysis of cocoa pod husk, sugarcane bagasse and banana pseudostem at 400 and 600 degrees C in order to use them as an organic amendment and to evaluate their capacities to reduce the bioavailability, methylation potential, and mobility of Hg present in mine tailings without environmental treatment. To quantify the effects of each variety of biochar, incubation experiments of soil were established by mixing mine tailings with 5\% by weight of biochar for 90 days. Once the incubation time concluded, sequential extraction procedures were carried out to determine the fractionation of the Hg species. Speciation analysis results indicated that the remedial effects of biochar depended on the source of organic matter and pyrolysis temperature. The bioavailable and organic Hg fractions decreased respectively by up to 75 and 79\%, indicating a methylation potential reduction. Immobile Hg fraction increased to 76\% with respect to the control. Adsorption and stabilization to HgS from the soluble forms of Hg reduce the percentage of bioavailable Hg. The organic Hg fraction reduction was correlated with the decrease of the bioavailable Hg fraction and with direct adsorption processes in the biochar structure. Highly porous biochars developed at high temperature, with large contents of superficial polar functional groups (H/C), and high pH, electrical conductivity, ash percentage and cation exchange capacity values favor the stabilization and adsorption of Hg in mine tailings. In summary, the application of biochar could be an effective method for the remediation of Hg-contaminated mine tailings, transforming the Hg species into less toxic, soluble, reactive, and bioavailable forms. (C) 2020 Elsevier B.V. All rights reserved.
We converted different biochars from nine common feedstock were prepared for aqueous NH4+ adsorption. The biochars were classified into three groups: wood-like (B@A: wood chips, white popinac wood, pinecone), shelllike (B@B: rice husk, longan shell, water caltrop shell), and other agricultural wastes (B@C: corncob, sugarcane bagasse, and coconut fiber). We aimed to characterize the cation exchange capacity (CEC), alkaline metal composition, and other physicochemical properties of biochars and to examine their relation to NH4+ adsorption. Our as-prepared biochars were mesoporous with a large surface area of 142-371 m(2)/g and highly negatively charged surface (pH(zpc) of 0.91-1.64). The ash contents and contact angle characterization distinguished the three biochar groups into: hydrophilic, low-ash B@A; super hydrophilic, high-ash B@B; and hydrophobic, mid-ash B@C. Alkaline metals (K, Na, Ca, and Mg) were found up to 40 g/kg, while CEC varied from 27.80 to 292.63 meq/kg. At {[
Interest on the use of lignocellulosic waste from second-generation (2G) ethanol industry has increased each year, where biochar and bio-oil production by pyrolysis is a relevant alternative. Biochar has high energy, adsorption capacity and soil enrichment potential, while bio-oil has applications for the pharmaceutical, chemical and fuel industries. Nonetheless, research on pyrolysis of this residue has not been reported, nor has the characterization of the bio-oil produced been profiled. Besides this, few studies on biochar and bio-oil produced from sugarcane bagasse have analyzed the effects of temperature and heating rate on yield. This work investigates the production and characterization of biochar and bio-oil by pyrolysis from this 2G waste. Temperature (500-700 degrees C) and heating rate (5-15 degrees C min(-1)) were the variables evaluated using a full factorial design (FFD), while biochar and bio-oil yields were the responses investigated. Characterization was carried out by thermogravimetric analysis, physical and chemical analyses, Fourier transform infrared spectroscopy, dispersive energy X-ray fluorescence spectroscopy (EDS) and gas chromatography-mass spectrometry (GC-MS). From FFD results, linear models were successfully fit to the responses. Maximum biochar and bio-oil yields of 40.3\% and 39.0\% were found for a set of temperature-heating rates of 500 degrees C-5 degrees C min(-1) and 700 degrees C-15 degrees C min(-1), respectively, in agreement with residue from first-generation ethanol process. The biochar presented low content of ash, volatile materials and moisture as well as high fixed carbon content and heating values, showing high energy potential. The bio-oil exhibited alternativity as source of phenols (53.2\%) for industry based on the GC-MS results.
A highly efficient, visible-light-driven and hybrid-activated carbon-doped pure tungsten trioxide (WO3) composite photocatalyst, with greatest stability has been synthesized by using hydrothermal method. Carbon nanoparticles were prepared by using sugarcane bagasse, and tungsten trioxide was prepared by using sodium tungstate (Na2WO4 center dot 2H(2)O) as a starting material. This study considers the photo-degradation of paracetamol by photocatalysis process, under visible-light irradiation. To study the properties of the prepared materials, SEM, TEM, FTIR, PL, and UV were performed. SEM was used to find the structure and size of the prepared materials. FTIR was used to analyze the presence of functional groups in the material. PL and UV were used to analyze the optical properties of the prepared materials. The SEM images of the prepared sample of WO3 showed that it has structure-like nanocubic and rectangular rods which become sharper by addition of carbon nanoparticles. The average size of the nanorods was about 50-550 nm. Some of the nanorods have smaller sizes about 25-250 nm which became beneficial for the photo-degradation process. UV-Vis spectroscopy showed that the band gap of the prepared samples varied from 2.78 to 2.26 eV, and this variation of the band gap was due to the variation in the concentration of the carbon nanoparticles. PL-spectroscopy analyzed the excitation wavelength of the prepared sample which was 448 nm. The efficiency of the prepared samples was evaluated by using paracetamol as target pollutant; carbon-doped composites of WO3 showed a greater photocatalytic performance as compared with the pure WO3. From the results of the photocatalytic activity, it was clear that composite having 2\% carbon has the highest efficiency to degrade the paracetamol.
The incorporation of biochar (BC) into agricultural soil changes the soil's physical properties, which leads to changes in the soil's hydraulic properties, such as water retention and permeability, and alters the soil moisture environment in agricultural fields. To elucidate the effects of the incorporation of BC on the soil moisture environment, measurements of the soil water in biochar-amended agricultural fields are needed. Time domain reflectometry (TDR) is a widely used and established technique for the continuous measurement of the soil water content (SWC) in agricultural fields. However, TDR measurements are affected by the conductivity of soils. Biochar formed at higher pyrolysis temperatures is known to be very conductive. Therefore, we investigated the influence of the incorporation of BC on TDR-based SWC measurements. We examined calcaric dark red soil and the BC produced by pyrolysis of sugarcane bagasse at 400, 600 and 800 degrees C. The apparent relative permittivity (epsilon(a)) of the BC (800 degrees C)-amended soil was greater than that of the non-amended soil at a given water content, whereas the epsilon(a) values of the soils amended with the BC (400 degrees C) and BC (600 degrees C) were the same as that of the non-amended soil at a given water content. We concluded that when a calibration curve obtained from a non-amended soil is used, TDR-based measurements tend to over-estimate the SWC containing the BC formed at higher pyrolysis temperatures because of conductive and dielectric losses. Therefore, the use of the real component ( epsilon r ) of the soil's complex relative permittivity instead of epsilon(a) is effective when making TDR-based water content measurements of soils that contain BC formed at higher pyrolysis temperatures.
In this work, 1,2,4,5-benzenetetracarboxylic acid (BT) is used as a cross-linker to improve the oxidative thermostabilization of lignin-rich nanofibers so that the activated carbon nanofiber (ACNF) sheets can be prepared from lignins. As sources, we used organosolv lignins from sugarcane bagasse (LB), para rubber wood chip (LR), and palm kernel shell (LP). The addition of BT imparts hydrogen bond interactions between BT and lignin and increases the oxidation degree of lignin during the stabilization, enabling retention of nanofiber morphology after heat treatments. The preparation of activated carbon in the form of nanofibers substantially enhances the specific surface area of the materials when compared with the activated carbon powders from pure lignins. The properties of the resulting ACNFs are influenced by the structure and composition of lignins. With the synergistic effects of a small fiber diameter (688 +/- 80 nm), a high content of heteroatom (0 atomic content similar to 5.1\%), a high graphitic carbon structure (I-D/I-G ratio similar to 0.98), a high conductivity (N-I>0.1nA/A similar to 3479 +/- 404 pixel mu m(-2) at 0.5 V), and a high specific surface area (similar to 2195 m(2) g(-1)), the ACNFs from LB show the highest specific capacitance of 182 F g(-1) (at a current density of 0.1 A g(-1) in 1.0 M H2SO4 electrolyte) with good cycling stability (95.7\% capacitance retention after 6000 cycles). A maximum energy density of 31 W h kg(-1) at a power density of 240 W kg(-1) can be achieved from the LB/PEO/BT ACNFs. Their performance is almost comparable to that of polyacrylonitrile ACNFs. These findings demonstrate a simple and effective approach to produce lignin-based ACNFs from diverse biomass feedstock for sustainable development of renewable materials for supercapacitor electrodes.
Biomass and distillery wastewater are promising sources to produce H-2-rich syngas through the thermal conversion. We propose the organic waste chemical looping gasification (OW-CLG) scheme for hydrogen production with straw stalk and concentrated distillery wastewater as feedstock. V2O3 was employed to promote methane reforming and enhance the efficiency of hydrogen production by partially oxidation. Experiments under different temperatures (T) and the molar ratio of V2O3 to CH4 (n(V2O3)/n(CH4)) are performed in details. The results show that the above parameters have a significant effect on OW-CLG process. The optimal methane conversion rate of 44.9 \% is obtained at oxygen excess ratio, temperature, and m(V2O3) /m(corn stalk) of 0.2, 700 degrees C, and 2.16 respectively. The highest H-2 yield is 2.05 l with 1 g corn stalk and 20 ml ethanol model solution. The reaction kinetics and the thermodynamics were analyzed, verifying that the introduction of ethanol liquid waste and V2O3 could boost hydrogen generation. The corn stalk OW-CLG is an endothermic process with the total endothermic heat of 5.396 kJ/mol. The thermodynamically feasible temperature range for the partial oxidation of CH4 to hydrogen by V2O3 is above 950 K. V2O3 OC during OW-CLG is regenerated by the reaction of VC and CO2.
The objective of this study was to evaluate the replacement of 0, 25, 50, 75 and 100\% of ground corn (GC) with pelleted soybean hulls (SH) in the concentrate portion of cattle diets. The evaluation was conducted using five 13-month-old Nellore steers cannulated in the rumen, with a mean body weight of 265.00 (+/-) 11.60 kg. The steers received a diet composed of 90\% concentrate and 10\% sugarcane bagasse as the only source of roughage. The statistical design used was a 5x5 Latin square. There was no effect (p > 0.05) of replacement levels or interaction (p > 0.05) between replacement levels and sampling time on ruminal pH, which ranged from 5.8 to 6.0. The apparent digestibility of DM, CP, EE, CHOT and CHONF were not influenced (p > 0.05) by the replacement levels, showing mean values of 67.88 (+/-) 2.02; 67.43 (+/-) 2.89; 68.29 (+/-) 4.11; 70.54 (+/-) 1.68 and 80.21 (+/-) 1.85\%, respectively. The NDF digestibility increased linearly (p < 0.05) with the replacement of corn with soybean hulls. There was no effect (p > 0.05) of replacement levels on time spent feeding (F) and total idle time (TI), with mean values of 10.51 and 4.61\% of the day, respectively. However there was a quadratic effect (p < 0.05) of soybean hull inclusion on the time spent ruminating. It was concluded that although the replacement of corn with soybean hull does not improve the ruminal pH of steers fed diets with a high proportion of concentrate, pelleted soybean hulls improve the digestibility of the fibrous fraction of the diet and increase the time spent ruminating, indicating that this ingredient can be included in high-concentrate diets to improve economic efficiency.
In this study, silver/graphene oxide (Ag/GO) nanocomposite was synthesized via the in - situ method using nanocellulose (NCs) obtained from sugarcane bagasse as a reducing agent. The synthesis conditions, including AgNO3:NCs mass ratio, temperature, and reaction time, were investigated. The results showed that the suitable condition was 1:1 in the AgNO3:NCs mass ratio at 60 degrees C for 60 min. The results indicated that the silver nanoparticles (AgNPs) were evenly distributed on the GO sheets with a size of 5 - 30 nm. Besides, the cytotoxicity of the Ag/GO nanocomposite was also assessed with three cell lines, including human embryonic kidney cells (HEK - 293), liver cancer cells (Hep - G2), and lung cancer cells (A549). Ag/GO possesses the ability to inhibit cancer cells of Hep-G2 and A549 with respective IC50 values of 86.11 +/- 1.74 mu g/mL and 106.85 +/- 2.15 mu g/mL. Therewithal, the antibacterial acrylic fabric (AF) was fabricated by dip - coating in an Ag/GO suspension (Ag/GO/AF). The Ag/GO/AF was hydrophobically modified with 5 g/L of stearic acid (Ag/GO/AF - SA) in ethanol solvent for 180 min, resulting in the fabric having high hydrophobicity with a contact angle of 116 degrees. Additionally, the plate diffusion method was used to evaluate the antibacterial activity of fabrics against two strains of Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus) bacteria. The results showed that the Ag/GO/AF - SA has an antibacterial ability with a large antibacterial diameter of 24 +/- 0.34 mm and 25 +/- 0.35 mm for P. aeruginosa and S. aureus, respectively. Moreover, the colorfastness of Ag/GO/AF and Ag/GO/AF - SA also possess high durability.
There has been a recent increase in both the production and consumption of ethanol due to the numerous environmental advantages that it offers, such as the fact that it can be produced from a variety of renewable materials, for instance corn and cellulose, or it can be obtained from sugarcane bagasse and biomass (2nd and 3rd generation ethanol). The result of this is that nowadays ethanol is widely seen as the dominant biofuel - or as a blend component in gasoline or pure fuel - in many countries. However, one disadvantage of the use of ethanol is the high corrosive behavior that occurs when its hygroscopic properties are exposed to a large number of materials. Xiaoyuan Lou and Preet Singh showed that the increase of water concentration in ethanol induces pitting and metal loss. Diamond-Like Carbon (DLC) films may be a solution to this problem due to the fact that they can be deposited inside tubes, offer good protection levels against corrosion, and reduce the friction coefficient and wear. This paper shows the tribocorrosion and corrosion studies of DLC films deposited on stainless steel grade 304 (SS304) substrates in order to gauge its appropriateness usage in the construction of pipelines and fuel storage tanks. The surface morphology was analyzed before and after 14 days of immersion. The tribocorrosion, friction coefficient, and wear rate were studied in ethanol to see the effects of water concentration. The films showed good adherence to the substrates. Corrosion and tribocorrosion results showed that for bare Stainless Steel 304 the increase of the water content increases the corrosion and the friction coefficient. DLC coated samples presented few points of delamination, and the friction coefficient and open circuit potentials were very low compared with the bare sample which was water concentration independent.
The recalcitrance of lignocellulosic biomass is a major factor limiting its conversion into biofuels. Therefore, in this study, we pretreated corn stalk with 2\% Na2CO3 and 2\% H2O2 for time 70 min at 130 degrees C using a corn stalk to liquid ratio of 1:10. The fermentation broth from multicopy Saccharomyces cerevisiae strains engineered for lignocellulase synthesis was used to enzymatically hydrolyze the pretreated corn stalk. The highest monosaccharide yield (102 mmol/L) was obtained using 15 IU endocellulase, 10 IU exocellulase, and 15 IU beta-glucosidase per gram of cellulose and 20 IU xylanase per gram of hemicellulose. Subsequently, the high-efficiency ethanol-producing S. cerevisiae strain WXY12, which can produce ethanol from glucose and xylose simultaneously, was added to the fermentation system. The entire process involved ethanol production through simultaneous saccharification and fermentation (SSF). Optimization of the fermentation conditions (yeast powder as a nitrogen source, temperature of 30 degrees C, MgSO4 as a metal ion inducer, rotation speed of 180 rpm, solid-liquid ratio of 1:8, and inoculation amount of 2\%) resulted in an ethanol output of 46.87 g/L and a theoretical conversion rate of 27.4\%. The results of this study improved corn stalk utilization, reduced hydrolysis costs, and generated high ethanol yields.
In this study we test a novel approach to closing the anthropogenic nutrient cycle, by using the freshwater macroalga, Oedogonium intermedium, to recover dissolved nitrogen (N) and phosphorous (P) from municipal wastewater. We then convert this cultivated algae into two types of soil ameliorant; compost and biochar. To produce compost, algae was combined with sugarcane bagasse and left to mature for 10 weeks, and to produce biochar, algae was processed through slow pyrolysis at 450 degrees C. The mature compost had a total N and P content of 2.5\% and 0.6\%, which was 2- to 4-times lower than the algal biochar, which had a total N and P content of 5.5\% and 2.5\% respectively. Composting stabilized the N and P recovered from wastewater, with 80\% of the initial N and >99\% of the initial P retained in the mature compost. In contrast, only 29\% of the initial N and 62\% of the initial P was retained in the biochar. When the mature compost was added to a low fertility soil it significantly increased the production of sweet corn (Zea mays). Treatments receiving 50 and 100\% compost produced 4-9 times more corn biomass than when synthetic fertilizer alone was added to the low fertility soil. When biochar was applied in conjunction with compost there was an additional 15\% increase in corn productivity, most likely due to the ability of the biochar to bind labile N and P and prevent its loss from the soil. This study demonstrates a unique model for recovering N and P from municipal wastewater and recycling these nutrients into the agricultural industry. This could be an ideal model for regional areas where agriculture and water treatment facilities are co-located and could ultimately reduce the reliance of agriculture on finite mineral sources of P. (C) 2017 Elsevier Ltd. All rights reserved.
Polycyclic aromatic hydrocarbons (PAHs) contaminations in Ghanaian smoke-cured fish are known to be in high levels. This may be linked to the recent upsurge of cancer cases among the population because PAHs are well-known carcinogens. A modified traditional kiln fitted with charcoal filters to remove PAL-Is by adsorption from the smoke before it contacted the fish being smoke-cured was designed. Smokecuring was done for 4 h with three most used smoke wood types- in Ghana namely acacia, sugarcane bagasse and mangroves. The smoking was done with no charcoal filter and compared to smoking with two types of activated charcoals fitted to the designed traditionally modified kiln. PAHs in smoke-cured fish samples (n = 108) using the designed system were analysed using Varian GC/MS (3800-GC) system. The mean total PAHs levels in the experimental smoked fish samples analysed ranged from 212.56 to 472.98 iig/kg in samples smoke cured with - activated charcoal filters. The mean percent reductions (efficiency of Kiln) were 21-69\%. The mean Benzo{[
The present study investigates fluoride concentrations from 9 locations in Rajasthan, India, and its associated health risk to the local inhabitants. pH, total dissolved solids (TDS), electrical conductivity (EC), chloride, hardness, and dissolved oxygen (DO) were among the other qualitative parameters measured, where the mean recorded values were 8.5, 723.9 mg/l, 1510 mu S/cm, 462.63 mg/l, 32.3 mg/l, and 6.3 mg/l, respectively. All of the tested samples had fluoride above the threshold value. To assess the fluoride health risk, the average daily dosage (ADD) and ingestion hazard quotient (IHQ) were evaluated for residents for ages 1 to > 80. Further work developed a low-cost household water filter for efficient fluoride remediation. The design is a low-cost gravity water filter prepared with diverse raw materials such as cement, sand, clay, ceramic, sugarcane bagasse, sawdust, potato gel, and activated carbon. Eight filters using different combinations of raw materials-four each of cement and ceramic as the base material-were tested for quality and flow rates over 30 days. The mean discharges measured through filters ranged from 0.034 to 1.17 l/h, with fluoride removal efficiency varying from 23.53 to 67.64\% for the cement filters and 29.41 to 37.53\% for ceramic filters. With the switch from cement to ceramic as the raw material, the filters' mean pore size varied from 1.432 to 0.013 mu m. The per-area costs for the cement and ceramic filter ranged from INR 60.28 to 116.76 and INR 805.95 to 1023.90, respectively. The best filter combination was tested for field samples, with a fluoride removal rate of 88.55\%.
Petroleum hydrocarbon (PHC) contamination of soil is a widespread global environmental concern due to the persistence and recalcitrant nature of PHCs. The PHCs are highly toxic and their removal from the terrestrial ecosystem is necessary to maintain soil as well as human health. Here, a pot experiment was performed to examine the impact of Enterobacter sp. MN17 and biochar addition on the growth of mungbean plants and PHCs removal from diesel-polluted soil. For this purpose, soil was contaminated artificially with diesel to achieve a final concentration of 5000 mg kg(-1). Untreated and Enterobacter sp. MN17 treated mungbean seeds were sown in pots. Sugarcane bagasse biochar was applied as an amendment in respective pots along with the recommended levels of essential nutrients. Results showed that PHCs significantly suppressed the seedling emergence as well as agronomic and physiological attributes of mungbean as compared to un-contaminated controls. However, the co-application of Enterobacter sp. MN17 and biochar significantly reduced the phytotoxicity of PHCs to mungbean plants and effectively increased the seedling emergence, shoot and root length, shoot fresh and dry biomass, root fresh and dry biomass of plants up to 24\%, 54\%, 52\%, 52\%, 54\%, 55\% and 60\%, respectively as compared to controls. Similarly, 30\%, 57\%, 64\%, 36\% and 57\% increase in chlorophylls contents, transpiration rate, stomatal conductance, sub-stomatal conductance, and photosynthetic rate, respectively were observed in their combined application as compared to respective controls. Furthermore, the co-addition of biochar and Enterobacter sp. MN17 could remove 69\% and 85\% higher PHCs from unplanted and planted pots, respectively, than that of their respective controls. Our results suggest that the co-application of biochar and Enterobacter sp. MN17 may be useful in enhancing plant growth and eliminating PHCs from contaminated soil.
Polysaccharide hydrolase producing bacteria were isolated for biomass saccharification step in two-step bioethanol production. Xylanolytic bacteria were found to be common in ruminant dung. Seven Bacillus dung isolates exhibited high xylanolytic activity; three of which were identified as Bacillus safensis and four as Bacillus altitudinis, based on 16S rDNA and gyrB gene sequencing. Interestingly, comparison of activity profiles for B.safensis M35 and B.altitudinis R31 and J208 crude xylanases showed activity in similar temperature and pH ranges of 40-60 degrees C and 60-90, respectively, even though they were isolated from three different dung sources. Furthermore, 22-28\% viscosity reduction of beechwood xylan substrate by all the three xylanases points towards their endo-acting nature. Endo-acting xylanases are envisaged as accessory enzymes which help expose the cellulose fibres for the subsequent action of the core enzyme cellulases. In this study, when supplemented to the commercial cellulase as a cocktail, the accessory role of the crude xylanases from the selected Bacillus strains was established as 13, 233 and 19 fold increase in saccharification of barley husk, sugarcane bagasse and wheat husk was achieved, respectively. Significance and Impact of the Study The uncontrolled use of fossil fuels and concerns about its future availability, have invoked interest over unconventional alternative energy sources like solar, hydropower, geothermal, nuclear and biomass. Plants, being largest renewable biomass on earth, have received consideration as a source of biofuels. Ruminant dung isolates M35, R31 and J208 belonging to Bacillus sp. produces majorly endo-xylanase when induced with wheat bran. Such plant cell wall degrading endo-xylanases with broad pH optima and mesophilic nature can act as accessory enzymes with cellulases to enhance the saccharification of plant biomass in biofuel industries.
Microbial xylanases that are thermostable, active at alkaline pH and cellulase-free are generally preferred for biobleaching of paper pulp. We screened obligate and facultative marine fungi for xylanase activity with these desirable traits. Several fungal isolates obtained from marine habitats showed alkaline xylanase activity. The crude enzyme from NIOCC isolate 3 (Aspergillus niger), with high xylanase activity, cellulasefree and unique properties containing 580 U l(-1) xylanase, could bring about bleaching of sugarcane bagasse pulp by a 60 min treatment at 55degreesC, resulting in a decrease of ten kappa numbers and a 30\% reduction in consumption of chlorine during bleaching. The culture filtrate showed peaks of xylanase activity at pH 3.5 and pH 8.5. When assayed at pH 3.5, optimum activity was detected at 50degreesC, with a second peak of activity at 90degreesC. When assayed at pH 8.5., optimum activity was seen at 80degreesC. The crude enzyme was thermostable at 55degreesC for at least 4 h and retained about 60\% activity. Gel filtration of the 50-80\% ammonium sulphate-precipitated fraction of the crude culture filtrate separated into two peaks of xylanase with specific activities of 393 and 2,457 U (mg protein)(-1). The two peaks showing xylanase activity had molecular masses of 13 and 18 kDa. Zymogram analysis of xylanase of crude culture filtrate as well as the 50-80\% ammonium sulphate-precipitated fraction showed two distinct xylanase activity bands on native PAGE. The crude culture filtrate also showed moderate activities of beta-xylosidase and alpha-L-arabinofuranosidase, which could act synergistically with xylanase in attacking xylan. This is the first report showing the potential application of crude culture filtrate of a marine fungal isolate possessing thermostable, cellulasefree alkaline xylanase activity in blobleaching of paper pulp.
Hybrid aluminum matrix composites (HAMCs) are a new class of advanced materials that can be customized and engineered to achieve specific properties for specific applications in specific environments. HAMCs find a wide range of popularity in the transportation sector because of lower noise and lower fuel consumption over other materials. This research aims to synthesize, characterize, and test the physicomechanical characteristics of tetra hybrid (SiC, Al2O3, Gr, and sugarcane bagasse ash (SCBA)) reinforced HAMCs via powder metallurgy (PM) processing. Tetra hybrid reinforced HAMCs were synthesized using a pure Al matrix with fixed wt\% of primary reinforcements (5 wt\% SiC and 5 wt\% Al2O3) and varying wt\% of secondary reinforcements such as 0.5, 2.5, 4.5, and 6.5 wt\% Gr and 0.5, 2.5, 4.5, and 6.5 wt\% SCBA. It mainly focused on phase purity investigation using XRD, thermal analysis using TGA-DTA, and surface area and micropore size analysis using BET and physicomechanical tests to explore the materials' behavior of the newly synthesized HAMCs. The increase in wt\% of secondary reinforcements decreases both the density and porosity while increasing the hardness and compressive strength up to a certain level above which it begins to reverse because of the increase in wt\% of hard particles of SiC, Al2O3, and SCBA. The Vickers hardness and compressive strength of the AS4 HAMC with 10 wt\% (SiC+Al2O3) and 9 wt\% (Gr+SCBA) were improved by 446.40\% and 209.75\%, respectively. The newly synthesized tetra hybrid reinforced HAMCs showed superior physicomechanical properties compared to pure Al and single and double reinforced HAMCs. As a result, the new tetra hybrid reinforced HAMC material is predicted to have potential applications in automotive, aerospace, defense, and various other structural applications.
Recently, geopolymer concrete (GPC) has gained substantial consideration and commercial interest in the construction industry owing to the superior mechanical and chemical properties in comparison with the ordinary Portland cement (OPC) that it brings through the use of waste material and reduction in the CO2 emission. Previous research Studies revealed that different ratios of chemical oxide combination of the raw material (fly ash, rice husk ash, meta kaolin, sugarcane bagasse ash, GGBS etc.) strongly affect the mechanical and durability properties of GPC. Nevertheless, findings concerning different ratios of Si/Al, alkaline solution to binder, NaOH to Na2SiO3, combined percentage of Fe2O3 + CaO and molar concentration of NaOH are controversial regarding the compressive strength of GPC. Therefore, in the light of literature, this study presents the investigation of the compressive strength behavior against the different ratios of oxides and alkaline solution (i.e. Si/Al, alkaline solution/binder, NaOH/Na2SiO3, Fe2O3 + CaO and NaOH molar concentration) present in the raw material used for the production of GPC. An extensive data from previous research publications has been collected and trend of compressive strength for 7 and 28 days was developed against different ratios of Si/Al, alkaline solution/binder, NaOH/Na2SiO3, in order to conclude a typical range for the above mention parameters. It was concluded that compressive strength of GPC greatly depends on the variation in ratios of Si/Al, alkaline solution/binder, NaOH/Na2SiO3, Fe2O3 + CaO and NaOH molar concentration. It was also concluded that the compressive strength of GPC has been primarily affected by the ratio of Si/Al, alkaline solution/binder, NaOH/Na2SiO3 and molar concentration of NaOH. Besides, the oxides like CaO and Fe2O3 although smaller in quantity in comparison with the alumina and silicate oxides, have indicated a distinct influence on the compressive strength development.
This study provides a first attempt investigation of a serie of studies on the ability of Anthracophyllum discolor, a recently isolated white-rot fungus from forest of southern Chile, for the treatment of soil contaminated with pentachlorophenol (PCP) to future research on potential applications in bioremediation process. Bioremediation of soil contaminated with PCP (250 and 350 mg kg(-1) soil) was investigated with A. discolor and compared with the reference strain Phanerochaete chrysosporium. Both strains were incorporated as free and immobilized in wheat grains, a lignocellulosic material previously selected among wheat straw, wheat grains and wood chips through the growth and colonization of A. discolor. Wheat grains showed a higher growth and colonization of A. discolor, increasing the production of manganese peroxidase (MnP) activity. Moreover, the application of white-rot fungi immobilized in wheat grains to the contaminated soil favored the fungus spread. In turn, with both fungal strains and at the two PCP concentrations a high PCP removal (70-85\%) occurred as respect to that measured with the fungus as free mycelium (30-45\%). Additionally, the use of wheat grains in soil allowed the proliferation of microorganisms PCP decomposers, showing a synergistic effect with A. discolor and P. chrysosporium and increasing the PCP removal in the soil.
Soil reclamation through afforestation along with soil amendments is one of the most suitable practices to combat soil salinity while the use of biochar may have potential to ameliorate salt-affected soils. This study was designed to check effects of different biochars on the physico-chemical properties of soil and characteristics of three important agroforestry trees species: Eucalyptus camaldulensis, Vachellia nilotica and Dalbergia sissoo, in saline soils. Farmyard manure biochar (FYMB), sugarcane bagasse biochar (SCB), woodchips biochar (WCB) were applied (6\% w/w) to check their effects on plants under saline conditions. Results revealed that FYMB was the best for promoting all growth and physiological parameters of three tree species while E. camaldulensis was the best suited species. Different types of biochars influenced the growth of agroforestry species differently as SCB showed better results for D. sissoo as compared to WCB but for V. nilotica and WCB was more effective than SCB. Trend of growth and other physiological attributes for E. camaldulensis and V. nilotica was FYMB > WCB > SCB > control whereas D. sissoo showed trend as FYMB > SCB > WCB > control. Biochar was helpful in improving physicochemical characteristics of saline soils by lowering values of soil EC and SAR but type of biochar has a differential effect on tree growth. Novelty statement Biochar may be a potential source for the amelioration of salt affected soils while less is known about the effects of different types of biochars on the soil and eco-physiological response of important agroforestry trees species in saline soils. In this study, although all types of biochar ameliorated the soil conditions and enhanced the plant growth, but farmyard manure biochar was the most efficient treatment among three types of used biochars.
Biofiltration of an air stream containing benzene has been studied in a laboratory biofilter packed with a mixture of compost, sugar cane bagasse and GAC. In this study, the overall performance of a biofilter has been evaluated in terms of its elimination capacity by using 3-D mesh techniques. The overall results indicate that the agreement between experimental data and estimated model predictions is excellent for benzene. The benzene concentration profiles along the depth of biofilter have also been determined using a convection-diffusion reactor (CDR) model and computational fluid dynamic (CFD) technique. At low flow rates and low concentrations of benzene, the concentration profile throughout the biofilter shows good agreement with CDR model and it becomes more curved and resembles typical decay. Combined analysis of experimental results with CDR model and the CFD shows that the profile of benzene at low concentration becomes more curved and then linear at high concentration. The benzene profiles obtained by CFD are within 5\% accuracy of experimental results. The CDR and CFD models are found to be able to predict concentration profiles preciously with depth under the experimental conditions. Crown Copyright (C) 2012 Published by Elsevier Ltd. All rights reserved.
In order to solve the problem of cherry rain-cracking, cold-water fish gelatin (CFG)-based edible films (CFG, CFG-CNC {[
Heat transfer studies were carried out in packed-beds (PBs) heated by the wall and percolated by low air flow rates. Porous media were composed by particles of sugarcane bagasse (SCB) and by a mixture of particles of SCB, orange pulp and peel (OPP) and wheat bran (WB) at proportion SCB:OPP: WB 1:2:2 w/w (composed medium), agricultural waste used as substrates in bioreactors of solid-state fermentation (SSF), an interesting biotechnological application of PBs. Once metabolic heat generated has to be dissipated, heat transfer studies and thermal parameters are required. Tube-to-particle diameter ratio was D/d(p) = 260, bed height ranged from L = 60 to 180 mm, while air flow rate ranged from 400 to 1200 L/h. Air temperature was 40 degrees C and wall temperature 65 degrees C. The outlet bed temperatures (T-L) were measured by ring-shaped sensors and by aligned thermocouples. Average temperatures (T-avg) and global heat transfer coefficients (U) were calculated separately for central region of the beds and for wall-vicinity. Radial effective thermal conductivity (Lambda(r)) and wall-to-fluid convective heat transfer coefficient (alpha(wall)) have been estimated by means of the traditional two-parameters model. Radial temperature profiles at bed outlet were flattened in the central region and convergent at the edge of the packs. The two-regions approximation for U calculations showed to be appropriate for both packs. Global coefficient U, thermal conductivity Lambda(r) and convective coefficient alpha(wall) increased with increasing air flow rate and decreased with bed height. Lambda(r) tended to the stagnant value of the thermal conductivity and alpha(wall) were lower than 50 W/m(2)/degrees C, addressing the difficulty on removing metabolic heat from PBs of SSF. (C) 2018 Elsevier Ltd. All rights reserved.
The impetus to predicting future biomass consumption focuses on sustainable energy, which concerns the non-renewable nature of fossil fuels and the environmental challenges associated with fossil fuel burning. However, the production of rice residue in the form of rice husk (RH) and rice straw (RS) has brought an array of benefits, including its utilization as biofuel to augment or replace fossil fuel. Rice residue characterization, valorization, and techno-economic analysis require a comprehensive review to maximize its inherent energy conversion potential. Therefore, the focus of this review is on the assessment of rice residue characterization, valorization approaches, pre-treatment limitations, and techno-economic analyses that yield a better biofuel to adapt to current and future energy demand. The pre-treatment methods are also discussed through torrefaction, briquetting, pelletization and hydrothermal carbonization. The review also covers the limitations of rice residue utilization, as well as the phase structure of thermochemical and biochemical processes. The paper concludes that rice residue is a preferable sustainable biomass option for both economic and environmental growth.
Gypsum is widely used in agriculture in the Cerrado region of Brazil to increase root volume and distribution in the profile of predominantly acidic soils with high aluminium toxicity. The gypsum-induced increase in the root system may be an effective strategy to increase sequestration of atmospheric CO2. However, few studies have investigated the relationship between the use of gypsum and carbon accumulation in the soil under sugar cane. In the present study, total carbon stock (TC) in the soil and its fractions were estimated after four growing seasons of sugar cane under gypsum application. The experiment was arranged in a randomised block design with four replicates and two treatments: control (0 Mg ha(-1)) and the technically recommended rate of gypsum application (5 Mg ha(-1)). Sugarcane stalk biomass and straw production were evaluated in plant cane and three ratoon crops. Soil samples were taken after evaluation of the third ratoon from seven layers (0-5, 5-10, 10-20, 20-40, 40-60, 60-80 and 80-100 cm) to determine organic carbon, TC, particulate carbon (PC) and bulk density. Gypsum increased TC by 5.4 and 4.4 Mg ha(-1) in the 0-100 and 40-100 cm layers respectively. The PC pool in the 40-100 cm layer was increased by 18.4\%, whereas the carbon stock associated with mineral increased by 6.8\% with gypsum application. Of the total increase in C stocks resulting from gypsum application, 80\% occurred in the 40-100 cm layer.
The present study evaluated the effects of different carbohydrates materials used as carbon sources on water quality, biofloc quality, and growth and productive performance of Nile tilapia (Oreochromis niloticus) reared in biofloc (BFT)-based cement ponds (25 m x 10 m x 1.2 m; with 250 m(3) volume). Nile tilapia fingerlings (44.9 +/- 1.9 g) were distributed into nine ponds at a density of 40 fish per 1 m(3) (10000 fish/pond) to represent three treatments in triplicates. The control ponds received no carbon source addition; meanwhile sugarcane molasses (MO) and wheat flour (WF) were added to ponds. A commercial diet (30\% crude protein) was offered to fish in each pond at levels of 3\% and 2\% of live body weight of fish in the control and BFT-based ponds, respectively, for 12 weeks. The amounts of feed were divided equally to three equal portions and offered to fish at 9:00, 13:00, and 17:00 h. The control ponds' water was replaced by 50\% every day with new water; meanwhile in MO and WF ponds, water loss via evaporation or leakage was compensated to reach the 1.0 m depth only. The pH value as well as unionized ammonia and nitrite levels, in the present study, were significantly lower, meanwhile nitrate and total suspended solids levels were significantly higher in MO and WF-treated ponds than the control one. The WF treatment resulted in significantly larger biofloc volume and higher total bacterial count compared to the MO treatment. The highest growth and production indices of Nile tilapia were observed in the BFT-based treatments as compared with the control group; particularly at the WF treatment followed by the MO treatment. In conclusion, the WF addition to cement fishponds is a more beneficial carbonaceous source for the efficient water quality, biofloc biomass, and growth and productivity of Nile tilapia reared in BFT-based system.
Cellulolytic enzymes were produced from the three fungal strains {[
Due to environmental issues, many methods of exploiting renewable natural resources are alternatives to reduce the dependence on non-renewable agricultural inputs. Phosphate fertilization on weathered tropical soil and waste reuse, for example, requires better management strategies. Thus, biochar from organic residues can be a strategy to reduce pressure on natural resources, in addition to having the potential to mitigate climate change. This study aimed to evaluate the availability of P in tropical soils from the interaction of biochar and arbuscular mycorrhizal fungi (AMF) in the aboveground and root systems of the plant and its impact on greenhouse gas (GHG) emissions. The results indicated that the addition of biochar was an alternative for C sequestration and GHG mitigation, causing no damage to the plant. The applied biochar amount had, for the most part, emission equal to or less than the control treatment (soil only). The sugarcane straw biochar (BCS) showed higher emissions, mainly in the presence of P and AMF. Biologically speaking, there was no significant effect in the presence of mycorrhizae. However, with regard to plant production, treatments where mycorrhizae were inoculated, longer and wider leaves were found. In the production of maize (Zea mays L.) plant material (aboveground and root), the upper and lower values were related to the poultry manure biochar (BPM) , and the presence of P, the values were lower, indicating that, for the good development of the plant, only the presence of the biochar is sufficient, without requiring the addition of phosphate fertilizer.
Cellulolytic actinobacterium, Promicromonospora sp. VP111 concomitantly produced cellulases (CELs), xylanase and pectinase when grown on commercial cellulose and untreated agricultural lignocellulosic residues (wheat straw and sugarcane bagasse). Secreted CELs hydrolyzed (enhanced with Co2+ ion) multiple cellulosic substrates, including sodium carboxymethyl cellulose (Na-CMC), Whatman filter paper no. 1, microcrystalline cellulose (avicel), p-nitrophenyl-beta-D-glucopyranoside (pNPG), laminarin, and cellulose powder. The CELs showed stabilities in the presence of various chemicals, including glucose (0.2 M), detergents (1\%, w/v or v/v), denaturants (1\%, w/v or v/v), and sodium chloride (NaCl, 30\%, w/v). The CELs were fractionated using ammonium sulfate precipitation and dialysis. Activities (\%) of fractionated CELs were retained at 60 degrees C for endoglucanase/carboxymethyl cellulase (CMCase) (88.38), filter paper cellulase (FPase) (77.55), and beta-glucosidase (90.52), which indicated of thermo-stability. Similarly, the activities (\%) for CMCase (85.79), FPase (82.48), and beta-glucosidase (85.92) at pH 8.5 indicated of alkaline-stability. Kinetic factors, K-m and V-max for endoglucanase component of fractionated CELs were 0.014 g/l and 158.23 mu M glucose/min/mL, respectively. Fractionated CELs yielded activation energies (kJ/mol) of 17.933, 6.294, and 4.207 for CMCase, FPase, and beta-glucosidase activities, respectively in linear thermostable Arrhenius plots. Thus, this study reports on the multipurpose CELs from an untreated agricultural residue utilizing Promicromonospora in relation to broad substrate specificity, halo-tolerance, alkaline-tolerance, detergent-tolerance, thermo-tolerance, organic solvent-tolerance, and end product-tolerance.
Smoke released from the burning of incenses, a quotidian practice in India, is found to contain many toxic chemicals on particles making it a prominent source of indoor air pollution. This study analyzes the smoke and ash particles emitted from a popular incense brand in India, inside an experimental chamber. Emission factor (EF) for PM3.2 generated from burning the incense is found to be 12.5 +/- 4.2 mg/g which is higher than the EF of biomass like sugarcane, rice straw and fuelwood (range: 1.69-10.9 mg/g). This EF value is either in the same range or higher than some of the incenses from Japan, Taiwan, and Thailand. From 60 to 70\% of the PM3.2 mass collected consists of particles less than 1 mu m in size. The maximum particle number count emitted from the incense exceeds 10(7) which is three orders of magnitude (i.e., 10(3)) higher than the number count reported in another study from Italy (10(4)). The composition of water-soluble ions and particle-bound metals in the smoke is similar to that reported for incense-based studies worldwide. This is the first study in India focusing on emission characteristics from burning incense in an experimental chamber, eliminating any external interference. Toxic elements like iron, zinc, and lead, affecting health substantially, on regular exposure are also detected. Studies have revealed that the toxicity associated with incense emissions can be higher than cigarette smoke. More comprehensive chemical analysis of the incense smoke and relevant health risk exposure is highly recommended.
This study aimed at evaluating the effects of feed intake level on the efficiency of rumen microbial protein synthesis (EMPS), nitrogen (N) excretion, and N balance in twelve 18-months old Boran (Bos indicus) steers with initial average liveweight of 183 kg (standard deviation (SD) 15.2). The experiment followed a 4x4 complete Latin Square design with four dietary treatments tested in four periods. Each period ran for 5 weeks with 3 weeks of adaptation and 2 weeks of sample collection; separated by 2 weeks of re-feeding. Steers were fed at 100\%, 80\%, 60\%, and 40\% of their metabolisable energy requirement for maintenance(MER, referred to as MER100, MER80, MER60, and MER40, respectively). Steers receiving MER80, MER60, and MER40 were only fed Rhodes grass hay. MER100 steers were offered Rhodes grass hay at 80\% of their MER and cottonseed meal and sugarcane molasses at each 10\% of MER. Mean daily dry matter intake differed between treatments (p <0.001) and ranged between 2.1 kg/animal (SD 0.13) in MER40 and 4.5 kg/animal (SD 0.31) in MER100. Urinary N excretion and N balance did not differ between MER80, MER60, and MER40. According to contrast test, declining feed intake level from MER80 to MER40 reduced duodenal microbial crude protein flow (p <0.001), but did not alter the EMPS (g microbial N/kg digestible organic matter intake). Yet, if scaled to N intake, EMPS increased (p <0.049), whereas total N and faecal N excretions decreased linearly with declining intake level (p <0.001 for both variables). At similar grass hay intake, duodenal microbial crude protein flow was 41\% higher in MER100 than in MER80 steers (p <0.001). In cattle offered poor-quality tropical forage below their MER, the very low EMPS and thus microbial protein supply aggravate the negative effects of low dietary nutrient and energy intakes in periods of feed shortage.
Agricultural waste has been a prominent environmental concern due to its significant negative impact on the environment when it is incinerated, disposed of in landfills, or burned. These scenarios promoted innovations in the food packaging sector using renewable resources, namely agri-food waste and by-products such as bagasse, pulps, roots, shells, straws, and wastewater for the extraction and isolation of biopolymers that are later transformed into packaging materials such as bioplastics, biofilms, paper, and cardboards, among others. In this context, the circular bioeconomy (CBE) model is shown in the literature as a viable alternative for designing more sustainable production chains. Moreover, the biorefinery concept has been one of the main links between the agri-food chain and the food packaging industry. This review article aimed to compile recent advances in the food packaging field, presenting main industrial and scientific innovations, economic data, and the challenges the food packaging sector has faced in favor of sustainable development.
Nanocrystalline cellulose (NCC) and micro-powdered cellulose (MPC) were extracted from rice straw by mechanical and alkali treatment methods, then characterized via infrared spectroscopy and dynamic light scattering. A series of polyurethane nanocrystalline cellulose composite (PNCCC) and polyurethane micro-powdered cellulose composite (PMPCC) coatings were prepared with various loading levels of NCC and MPC from 0.5 to 2.0 wt.\%, and the coatings were applied onto the pretreated mild steel substrate at room temperature. The results showed that the NCC and MPC influenced positively the studied properties of the polyurethane coating; furthermore the most pronounced anticorrosive properties were obtained at 1 wt.\% NCC and MPC, as confirmed by open circuit potential (OCP) study, electrochemical impedance spectroscopy (EIS) study and salt spray test. However, the optimum enhancement of mechanical properties was found at 1.5 wt.\% loading level, after which further loading of NCC and MPC led to the reduction in the mechanical properties.
Soil pollution with hexachlorocyclohexane (HCH) has caused serious environmental problems. Here we describe the targeted degradation of all HCH isomers by applying the aerobic bacterium Sphingobium indicum B90A. In particular, we examined possibilities for large-scale cultivation of strain B90A, tested immobilization, storage and inoculation procedures, and determined the survival and HCH-degradation activity of inoculated cells in soil. Optimal growth of strain B90A was achieved in glucose-containing mineral medium and up to 65\% culturability could be maintained after 60 days storage at 30 degrees C by mixing cells with sterile dry corncob powder. B90A biomass produced in water supplemented with sugarcane molasses and immobilized on corncob powder retained 15-20\% culturability after 30 days storage at 30 degrees C, whereas full culturability was maintained when cells were stored frozen at -20 degrees C. On the contrary, cells stored on corncob degraded gamma-HCH faster than those that had been stored frozen, with between 15 and 85\% of gamma-HCH disappearance in microcosms within 20 h at 30 degrees C. Soil microcosm tests at 25 degrees C confirmed complete mineralization of {[
Two-year field experiments were conducted to study the effect of different levels of inorganic fertilizers, farmyard manure (FYM), and bio-inoculants on wheat productivity and profitability. Results specified that judicious application of inorganic fertilizers, FYM, and bio-inoculants significantly increased the productivity and profitability of wheat. Data suggested that the aggregate levels of fertilizer up to 100\% NPK ha(-1 )resulted in significant increases in all growth attributes, grain yield (+206\%), straw yield (+177\%), and harvest index (+7\%) as compared to control. Meanwhile, plots with the application of 10 t ha(-1) FYM significantly (p < 0.05) increased grain yield (+26\%) and straw yield (+22\%) as compared to the control. Similarly, significant enhancement in grain and straw yields was observed with the application of PGPR + VAM over no-inoculation. Results showed that the significantly higher grain and straw yield attained by application of 75\% NPK fertilizer + 10 t ha(-1) FYM was at par with the application of 100\% NPK fertilizer alone. Further, net returns (profitability) and B:C ratio (2.37) were significantly higher with fertilization with 75\% NPK + 10 t ha(-1) FYM along with PGPR + VAM as compared to 100\% NPK alone. Overall, it can be concluded that the combination of 75\% NPK and 10 t ha(-1) FYM along with PGPR + VAM represented the optimum for net return and B:C ratio and reduced (25\%) dose of NPK as compared to the rest of the treatment combinations.
Microbial consortia-based consolidated bioprocessing (CBP) is a promising trend in biomass biorefinery, but still faces challenges in terms of complicated microbial structure, low conversion efficiency and operation instability. This study constructed an artificial consortium with improved biomass conversion capability and good operation stability. Diversity of the microbial community structure and gene functions of the domesticated consortium was then analyzed, finding that it had a simplified microbial structure and aggregation of functional genes related to conversion of cellulosic materials for biofuel production. Finally, CBP of wheat straw was performed using the domesticated consortium, ethanol and solvent production with the highest yield ever reported at 0.37 g/g and 0.60 g/g respectively were achieved. Our results further highlight the potential of this domesticated consortium in lignocellulosic biomass biorefinery in comparison with previously reported microbial consortia. Overall, this study provides a guidance on the artificial construction of simplified functional consortia for producing valuable chemicals in a sustainable way. (c) 2022 Elsevier Ltd. All rights reserved.
This study describes the use of alternative operational strategies in the solid-state fermentation of the agroindustrial leftover sugar cane bagasse (SCB) supplemented with L-phenylalanine, for bioproducing natural 2-phenylethanol (2-PE) and 2-phenethyl acetate (2-PEA) using K marxianus. Here, fed-batch and sequential-batch have been assessed at two scales (1.6 and 22 L) as tools to increase the production, as well as to enhance the sustainability of this residue-based process. While in the reference batch strategy a maximum of 17 mg of 2-PE+2-PEA per gram of added SCB was reached at both scales, the implementation of fed-batch mode induced a production increase of 11.6\% and 12.5\%, respectively. Also, the production was increased by 16.9\% and 2.4\% as compared to the batch when a sequential -batch mode was used. Furthermore, the use of these strategies was accompanied by lower consumption of key resources like the inoculum, air, and time, promoting savings between 22\% and 76\% at both scales.
A hydrothermal alkaline synthesis of self-supporting zeolites from co-generation boiler sugar cane bagasse ash (SCBA) was measured by X-ray powder diffraction (XRD) scan yields (scan area percentages) method. A factorial design and a response surface statistical method were used to optimise the synthesis method. Temperature, NaOH concentration and aluminium/silica (Al/Si) ratio were determined to be the most influential factors in controlling zeolite-X yields, and these three variables were included in a response surface model (RSM) with a central composite design (CCD). The RSM model indicates that optimal zeolite-X formation conditions are 72.5 degrees C, 5 M NaOH and an Al/Si ratio of 3:5. The RSM/CCD matrix established an efficient statistical modelling of zeolite synthesis optimisation with the fewest possible number of experiments. Scanning electron microscopy examination shows that SCBA particles (20-100 mu m) are covered with zeolite crystallites (0.3-0.8 mu m in size) producing a self-supporting structure. XRD analyses show a dominance of zeolite-X (33.6\%), with zeolite-A (4.7\%), and an average Al/Si ratio of 4:5 that is close to published values. The Brunauer-Emmett-Teller (BET) apparent specific surface area measured 228 m(2) g(-1) (P/Po = 0.045), and approximate to 90\% of the micro-porosity distribution is associated with approximate to 7 angstrom internal micropore, which is typical of zeolite-X. The self-supporting, composite nature and large effective grain size of the zeolites reported in this work opens a number of uses for the materials produced.
Lactic acid is a versatile chemical with a wide range of industrial applications, including food additives as well as the production of biodegradable plastics, pharmaceuticals and cosmetics. LA can be produced through carbohydrate fermentation using various microorganisms, including lactic acid bacteria (LAB). However, the high production cost of commercial fermentation media for lactic acid raises concerns among researchers. Consequently, there is a demand for research to develop new, more affordable, and sustainable fermentation media. Utilizing underutilized agro-industrial wastes from Malaysia, particularly in the coconut, oil palm, rice, and sugarcane processing industries, offers several advantages. These include biomass reuse, cost-effective production of valuable chemicals, and agricultural waste reduction. This review discusses the potential of underutilized Malaysian agro-industrial waste from the coconut, oil palm, rice and sugarcane processing industries as sustainable carbon sources for LA production. The topics covered encompass the chemical and nutritional composition of the wastes, their potential for lactic acid fermentation with specific microorganisms, factors influencing lactic acid production, and potential applications. Additionally, this review also highlights the challenges and opportunities associated with reutilizing agricultural waste for lactic acid production.
With the in-depth study of photocatalytic degradation of antibiotics, it can be learned that photocatalysts show different performances when degrading different antibiotics. In this work, an efficient photocatalytic material was synthesized using TiO2 and bagasse, and its characteristics were verified by SEM, EDS, TEM, FT-IR spectroscopy, XRD, I-t, EIS, M-S, and UV-vis DRS. Tetracycline and ciprofloxacin were used as target contaminants to explore the degradation performance and degradation mechanism of catalysts for antibiotics with different properties. The experiments showed that the applicable pH range for ciprofloxacin was narrower and tetracycline required a higher dosage for effective degradation. The ESR and capture experiments showed that there were several reactive groups produced in the degradation system. Overall, the reactive species that played a major role in the degradation of tetracycline and ciprofloxacin were h(+), O-1(2), and h(+), respectively. Furthermore, it can also be seen that under acidic or alkaline conditions, the direct contact oxidation dominated by h(+) was weakened and the role of reactive species such as (OH)-O-center dot, O-center dot(2)- and e(-) in TC degradation and (OH)-O-center dot, O-center dot(2)- and O-1(2) in CIP degradation was strengthened, respectively. It is clear from the liquid mass that both the reactive groups and the pH of the solution impacted the production and elimination of intermediates. This work highlights the variability of the photocatalyst in degrading different pollutants, suggesting the need for more targeted preparation of photocatalysts.
Lignin particles were recovered from the bagasse soda pulping black liquor by acidification with carbon dioxide continuously fed in a semibatch reactor. An experimental model based on the response surface methodology was selected to investigate the effect of parameters and optimize the process for maximizing the lignin yield, and the physicochemical properties of the obtained lignin under the optimum conditions were investigated for further potential applications. A total of 15 experimental runs of three controlled parameters including temperature, pressure, and residence time were carried out based on the Box-Behnken design (BBD). The mathematic model for lignin yield prediction was successfully estimated at 99.7\% accuracy. Temperature played a more significant role in lignin yield than pressure and residence time. Higher temperature could faciltate a higher lignin yield. Approximately 85 wt \% lignin yield was obtained under the optimum conditions with a purity higher than 90\%, high thermal stability, and slightly broad molecular weight distribution. The p-hydroxyphenyl-guaiacyl-syringyl (HGS)-type lignin structure and spherical shape were confirmed by Fourier transform infrared spectroscopy (FTIR) and field emission scanning electron microscopy (FE-SEM). These characteristics confirmed that the obtained lignin could be used in high-value products. Moreover, this work indicated that the CO2 acidification unit for lignin recovery could be efficiently improved for achieving high yield and purity from black liquor by adjustment of the process.
Xylooligosaccharides (XOS) are emerging prebiotics, widely used in food, medicine and health care. XOS are produced by hydrolysis of xylan by acid or endoxylanase enzyme. Xylanase hydrolysis is preferred over acid due to its high specificity and absence of formation of non-toxic byproducts. Immobilized xylanase improves enzyme-stability and efficacy of XOS production through its repeated use. Though there are a few xylanases immobilized on conventional organic polymers for XOS production, immobilization of xylanse on mesoporous inorganic materials have not been investigated for XOS production. In this study, the recombinant endo-1, 4-beta-D-xylanase (XynC) of B.subtilis KCX006 was purified and immobilized on ordered mesoporous matrices of carbon (CMK-3), silica (SBA-15) and zirconia (ZMF-127). The immobilized-XynC was characterized and used for XOS production by recycling. The recovered activity (RA) of immobilized-XynC varied between 55 to 84\%. The maximum RA was observed for XynC immobilized on ZMF-127 matrix. All immobilized-XynC had optimum pH similar to that of free-XynC. But all immobilized-XynC gained broader temperature range (50-65 degrees C) for optimal catalytic activity when compared with the free-XynC. Immobilization of XynC resulted in higher K-m due to substrate diffusion limit. All immobilized-XynC produced free-XOS of DP 2-6 (X2-X6) and substituted-XOS from beechwood xylan and extracted crude xylans from sorghum stalks and sugarcane bagasse (SCB). The XynC immobilized on SBA-15 produced higher proportions of X2-X6 compared to ZMF-127 and CMK-3. The XynC immobilized on SBA-15 and CMK-3 retained higher activity of 85-93\% after four batches of repeated use. The observed efficiency of XynC immobilized on CMK-3 and SBA-15 are higher than the reported values. The results showed that XynC immobilized on mesoporous carbon and silica matrices would be useful for production of XOS by enzyme recycling.
Nowadays, isoamyl acetate production is carried out by chemical synthesis with a recent interest in developing biological producing processes, mainly based on microorganisms in submerged fermentation. This work assayed producing isoamyl acetate through solid-state fermentation (SSF), feeding the precursor in the gas phase. Polyurethane foam functioned as the inert support to contain 20 ml of a solution of molasses (10\% w/v, pH 5.0). The yeast Pichia fermentans was inoculated at 3 x 10(7) cells per gram of initial dry weight. The airstream to supply oxygen also served to supply the precursor. Slow supply was obtained using an isoamyl alcohol solution of 5 g l(-1) in the bubbling columns and an air stream of 50 ml min(-1). For fast supply, fermentations were aerated using 10 g l(-1) and 100 ml min(-1) for isoamyl alcohol solution and air stream, respectively. It demonstrated the feasibility of isoamyl acetate production in SSF. Moreover, the slow supply of the precursor increased isoamyl acetate production up to 390 mg l(-1), which is 12.5 times higher than that obtained without precursor (32 mg l(-1)). On the other hand, fast supply caused an evident inhibition of the growth and production capacity of the yeast.
Acetone-butanol-ethanol-water mixture is obtained by fermentation of biomass namely, corncob, wheat straw, sugarbeets, sugarcane, etc. For using the individual components, one alternative is to separate the mixture by distillation, which is costly and energy intensive operation. This paper proposes its other use in available conditions to produce hydrogen fuel by oxidative steam reforming process. For the proposed process, thermodynamic equilibrium modeling has been performed by using non-stoichiometric approach of Gibbs free energy minimization. The compositions of acetone, butanol and ethanol in mixture are 0.33:0.52:0.15 on molar basis. The influence of pressure (1-10 atm), temperature (573-1473 K), steam to ABE mixture molar feed ratio (F-ABE = 5.5-8.5), and oxygen to ABE mixture molar feed ratio (FoAsE = 0.25-1) have been tested by simulations on the yield of products (at equilibrium) namely, H-2, CH4 , CO2 , CO, and carbon as solid. The optimum conditions for maximum production of desired H 2 , minimization of undesired CH4, and elimination of carbon (solid) formation are T = 973 K, P = 1 atm, F-ABE = 8.5, and F-OABE = 0.25. Under same operating conditions, the maximum generation of H 2 is 7.51 on molar basis with negligible carbon formation. The total energy requirement for the process (295.73 kJ/mol), the energy required/mol of hydrogen (39.37 kJ), and thermal efficiency (68.09\%) of the reformer have been obtained at same operating conditions. The exergy analysis has also been investigated to measure the work potential of the energy implied in the reforming process.
Bio-oils of pine wood and sugarcane bagasse were obtained in different conditions of thermal and catalytic pyrolysis. They were analyzed by hydrogen nuclear magnetic resonance (H-1 NMR), comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GC x GC-TOFMS), and negative-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI(-)-FT-ICR MS) to provide a complementary and comprehensive characterization of the bio-oils. The elucidation of bio-oils composition is essential to assign the best application of bio-oils and the type of process required for upgrading methods. In general, the results obtained by H-1 NMR and GC x GC-TOFMS showed a decrease of oxygen compounds (especially acids) and an increase of aromatic compounds when catalytic pyrolysis was used. The compound classes identified in each sample by GC x GC-TOFMS were acids, ketones, cyclic ketones, phenols, O-heterocyclic, and aromatic hydrocarbons. ESI(-)-FT-ICR MS provides relative signals and the bio-oil compounds containing hydroxyl or carboxylic acid groups, such as carboxylic acids and phenols, are selectively ionized. Via ESIH-FT-ICR MS, the oxygen-containing compounds determined in bio-oil samples were from O-2-O-12 classes, with the O-4 being the major class. ESI(-)-FT-ICR MS results suggest that use of the ZSM-5 catalyst provides a decrease in the class abundance of higher oxygen atom number (>O-5 classes), and consequently, the increase of lower oxygen atom number classes (O-2-O-4). The integrated results from these three high-resolution techniques were important to comprehensively assess the molecular composition of bio-oils. The H-1 NMR provided the whole bio-oils composition profile assessment; GC x GC-TOFMS and ESI(-)-FT-ICR MS results allowed a detailed speciation of the chemical composition of bio-oils. (C) 2015 Elsevier B.V. All rights reserved.
The scope of this study was twofold: to define the most suitable Egypt's biodiesel source, and to assess the impact of this biodiesel source with the addition of carbon nano additives on diesel engine performance and emissions. Environmental Key Performance Indicators were used as metrics to identify the appropriate biodiesel source with respect to several criteria including environmental, economic, ecological, and demographic situation. The most suitable Egypt's biodiesel source was identified from different sources including algae, Jatropha, coffee waste, rice straw, sugarcane, and switchgrass. Then, the production process of biodiesel from this renewable source by transesterification was carried out using chemical catalyst or biocatalyst. Following this, this source's impact with carbon nano additives on the performance and emissions of a 0.825-L single-cylinder diesel engine was further examined at engine loads varying between 0 and 4 kW and 1500 rpm constant engine speed. The carbon nano additives were added at a different mass fractions of 25, 50 and 100 ppm to Jatropha biodiesel and diesel blend (20 \% jatropha biodiesel thorn 80 \% diesel) by volume. The results showed Jatropha as the most efficient biodiesel source among all the tested fuels to be produced in Egypt. Furthermore, the experimental engine test results revealed that Jatropha biodiesel without and with carbon nano additives consistently has a higher brake thermal efficiency and lower brake specific fuel consumption in comparison to that of diesel fuel. Likewise, Jatropha biodiesel without and with carbon nano additives enhanced the engine performance and consequently reduced the exhaust emissions including CO, CO2, HC, NOx, and smoke in comparison to that of diesel fuel. (C) 2021 Elsevier Ltd. All rights reserved.
The present study was carried out to investigate the serum minerals profile in buffaloes (Bubalus bubalis) suffering from parturient haemoglobinuria (PHU) along with minerals profile of soils and fodders from the disease prone areas and their interrelationships. Serum samples were collected from 60 each of healthy and PHU affected buffaloes randomly selected from field cases. Serum samples were collected from each animal. Fifty composite soil samples were collected where PHU was prevalent. Fifty samples of fodders including leaves and stems being fed to the diseased buffaloes were collected. The difference in the levels of calcium and potassium between upper and lower soil surface of disease prone areas under study were statistically non-significant. The mean values of phosphorous, copper, iron, selenium and molybdenum in upper soil surface were significantly (p < 0.05) higher than in lower soil surface. None of the fodders offered to the diseased animals met the dietary requirements of phosphorus and copper whereas none of the fodders was deficient in potassium, iron and selenium rather were having excess of potassium, iron and selenium. The concentration of calcium was adequate in lucerne, berseem, sarson and sorghum, while maize, sugarcane and wheat straw did not meet the required levels for dairy animals. Molybdenum contents in all fodders were adequate to meet the dietary requirements of the dairy buffaloes. Serum phosphorus, copper and selenium were significantly (p < 0.001) lower whereas potassium, iron and molybdenum in buffaloes suffering from PHU were significantly (p < 0.001) higher than in healthy buffaloes. It was concluded that phosphorous deficient soils play a major role by transferring this deficiency to plants and ultimately reaching to animals where hypophosphataemia is a consistent finding.
It is imperative to find suitable strategies to utilize the native soil phosphorus (P), as natural rock phosphate deposits are at a verge of depletion. We explored two such cost-effective and eco-friendly strategies for native soil P solubilization: silicon (Si)-rich agro-wastes (as Si source) and phosphate solubilizing microorganism (PSM). An incubation study was conducted in a sub-tropical Alfisol for 90 days at 25 degrees C under field capacity moisture. A factorial completely randomized design with 3 factors, namely: Si sources (three levels: sugarcane bagasse ash, rice husk ash, and corn cob ash), PSM (two levels: without PSM, and with PSM); and Si doses {[
1. This study was conducted to investigate the effect of particle size of insoluble fibre on growth performance, apparent ileal digestibility (AID) and caecal microbial population in broiler chickens fed barley-containing diets. 2. The dietary treatments included: a barley-based diet (control, CTL) or test diets which contained high-fibre ingredients, either sunflower hulls (SFH), sugarcane bagasse (SB) or wheat bran (WB) ground through a 1.0 (fine) or 3.0 mm (coarse) screen that were added to the control diet at 30 g/kg. 3. For the entire experimental period, insoluble fibre inclusion improved ADG (P < 0.05) and FCR (P < 0.05) compared to the CTL group. Broilers fed SFH had higher (P < 0.05) ADG and better (P < 0.05) FCR than broilers fed SB. 4. Fibre inclusion increased the relative weight of breast and thigh and decreased relative weight of liver compared to the CTL group, but coarse grinding of the SB decreased relative weight of abdominal fat (P < 0.05). 5. The digestibility of nutrients increased with dietary inclusion of insoluble fibre compared to the CTL group. Coarse grinding of SFH increased AID of crude protein compared to the coarse grinding of WB or SB. Fine grinding of various types of fibre improved the AID of fat (as ether extract) and organic matter (P < 0.05). 6. Fine grinding of the WB decreased caecal populations ofE. coli. The inclusion of SFH increased caecal populations ofLactobacillus spp. (P < 0.05). Coarse grinding of various types of fibre decreased the caecal population of coliforms (P < 0.05). 7. The inclusion of WB increased digesta viscosity in the ileum compared to samples from the SB and SFH groups (P < 0.05). Coarse grinding of various types of fibre decreased the digesta viscosity in the ileum (P < 0.05). 8. Overall, the data showed that dietary inclusion of insoluble fibre improved growth performance, increased AID of nutrients and decreased ileal viscosity in the birds fed diets containing barley.
In this work, bituminous coal, sugar cane, untreated and pretreated hazardous waste ashes are tested as supplementary cement materials, analyzing their reactivity in lime pastes prepared according to ASTM C-305, using a 0.5 water/lime ratio. The hydration process was stopped with acetone at the ages of 1, 3, 7, 14, 28, 56, 90 and 180 d. Mineral phases were determined by thermogravimetry, XRD, and SEM finding high contents of SiO2 and Al2O3 in the coal and sugarcane ashes, while in the hazardous waste ashes low contents of these oxides were found. Samples of sugarcane and untreated hazardous waste ashes seems to be attractive to be used as substitutes in the production of construction supplies. In addition to this, an E-factor analysis was carried out, which showed that carrying out fly ash replacements in any quantity contributes to the circular economy of all the economic activities involved. Reducing the amount of solid waste to be disposed of and improving the local and regional environmental quality.(C) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.
Agricultural residues are considered abundant raw materials that can be used to produce valuable chemicals like furfural. Currently, furfural production is characterized by extensive use of energy and low conversions. However, these challenges can be overcome through process intensification in conjunction with a suitable process synthesis. This work proposes the synthesis, design and optimization of furfural production processes using different intensified distillation and pretreatment alternatives. The eco-indicator 99 and total annual cost were considered as metrics to evaluate the performance of furfural processes. To determine the influence of biomass type on energy consumption, costs and environmental impact, four different biomasses are considered raw materials. The design and optimization of furfural processes were carried out using a two-step procedure. Firstly, all possible alternatives were simulated using Aspen Plus, then the best process option for each biomass is optimized using the differential evolution with tabu list method. The results indicate that a dilute acid pretreatment combined with a thermally coupled scheme provides the lowest cost and environmental impact for all feedstocks. Finally, the optimization results show that the best furfural process consists of wheat straw, dilute acid pre-treatment and thermally coupled distillation, owing to its lowest cost and environmental impact which are 13,092,504 dollars/year and 4,536,512 eco-points/year respectively.
This Review highlights the principal crops of Brazil and how their harvest waste can be used in the chemicals and materials industries. The Review covers various plants; with grains, fruits, trees and nuts all being discussed. Native and adopted plants are included and studies on using these plants as a source of chemicals and materials for industrial applications, polymer synthesis, medicinal use and in chemical research are discussed. The main aim of the Review is to highlight the principal Brazilian agricultural resources; such as sugarcane, oranges and soybean, as well as secondary resources, such as andiroba brazil nut, buriti and others, which should be explored further for scientific and technological applications. Furthermore, vegetable oils, carbohydrates (starch, cellulose, hemicellulose, lignocellulose and pectin), flavones and essential oils are described as well as their potential applications.
In this study, lignocellulose-assisted hydrothermal treatment (HTT) of digestated sludge was studied to further understand the role of biomass in HTT and its effect on subsequent sludge dewatering. HTT of sludge-biomass mixtures at 180 degrees C for 60 min at a sludge/biomass total solids (TS) ratio of 1:1 led to solid residue moistures of 36\%-40\% after dewatering using a hydraulic press at 24 MPa, compared to 69.5\% without biomass. Further investigation showed that organic acids, especially acetic acid generated from lignocellulosic biomass hydrolysed extracellular polymeric substances (EPS), especially EPS-protein, and improved sludge dewaterability. The role of organic acids was further verified with the addition of 10.0 g/L acetic acid for HTT of sludge at 180 degrees C in the absence of biomass. It was also observed that in HTT of sludge with 10.0 g/L acetic acid, protein nitrogen was converted to more stable forms of nitrogen such as pyrrole-nitrogen and quaternary-nitrogen. However, HTT with acetic acid alone resulted in dewatered solids with high ash contents, which may limit their applications as soil amendments. Combination of biomass and acetic acid with a sludge/biomass TS ratio of 3:1 and acetic acid loading of 10.0 g/L at a HTT temperature of 180 degrees C for 60 min led to solid moistures of 50.5\% with hardwood sawdust and 57.7\% with sugarcane bagasse after dewatering at 3 MPa, corresponding to total weight reductions of 66.3\% and 55.7\%, respectively. In contrast, HTT of sludge at 180 degrees C for 60 min without acetic acid and biomass resulted in a solid moisture of 76.6\% after dewatering at 3 MPa and a corresponding weight reduction of 49.5\%. With the use of biomass and acetic acid in HTT, the treated and dewatered solids also had increased carbon content and reduced ash content. These dewatered solids may be used as potential soil amendments though the properties related to soil applications need to be considered in future studies.
In the present work, with the focus on an environmentally-friendly approach, some gels were prepared by synthesizing amine-modified lignin, extracted from sugarcane bagasse, and further esterification and subsequent freeze-drying. These lignin-based gels were implemented as extractive phases in an online micro-solid phase extraction (mu SPE) setup in conjunction with high performance liquid chromatography (HPLC) with UV detector. The developed method was used for analytical determination of valsartan and losartan in urine samples. To study the effect of the functionalization process, the efficiency of the unmodified lignin and the functionalized lignin were compared both in the absence and the presence of graphene oxide (GO), presumably as a suitable doping agent. Surprisingly, higher extraction efficiency for the functionalized lignin, compared to both unmodified lignin and GO was observed. The amination process for the prepared gel was analyzed and proved by CHNS elemental analysis and Fourier transform infrared (FT-IR) spectroscopy. The morphology of sorbet was investigated via scanning electron microscope (SEM) imaging and a nanoscale cauliflower feature was observed. The method was optimized and subsequently applied to the analysis of the urine samples. Limits of detection (LOD) of 8 and 6 mu g L-1, limits of quantification (LOQ) of 27 and 20 mu g L-1 and linear dynamic range (LDR) of 27-20 00 and 20-20 00 mu g L-1 with intraday relative standard deviations (RSD\%) of 4 and 3\% were obtained for valsartan and losartan, respectively. The whole online mu SPE-HPLC setup was conveniently used for the analysis of a patient urine sample and a quantity of 352 mu g L-1 of losartan was found. Acceptable relative recoveries (109-108 and 95-94\% for valsartan and losartan) revealed the analytical potential of the method for the determination of drugs in complex urine samples. (C) 2021 Elsevier B.V. All rights reserved.
Hydrogen is a valuable clean energy source, and its production by biological processes is attractive and environmentally sound and friendly. In Mexico 5 million tons/yr of agroindustrial wastes are generated; these residues are rich in fermentable organic matter that can be used for hydrogen production. On the other hand, batch, intermittently vented, solid substrate fermentation of organic waste has attracted interest in the last 10 years. Thus the objective of our work was to determine the effect of initial total solids content and initial pH on H-2 production in batch fermentation of a substrate that consisted of a mixture of sugarcane bagasse, pineapple peelings, and waste activated sludge. The experiment was a response surface based on 22 factorial with central and axial points with initial TS (15-35\%) and initial pH (6.5-7.5) as factors. Fermentation was carried out at 35 degrees C, with intermittent venting of minireactors and periodic flushing with inert N-2 gas. Up to 5 cycles of H-2 production were observed; the best treatment in our work showed cumulative H-2 productions (ca. 3 mmol H-2/gds) with 18\% and 6.65 initial TS and pH, respectively. There was a significant effect of TS on production of hydrogen, the latter decreased with initial TS increase from 18\% onwards. Cumulative H-2 productions achieved in this work were higher than those reported for organic fraction of municipal solid waste (OFMSW) and mixtures of OFMSW and fruit peels waste from fruit juice industry, using the same process. Specific energetic potential due to H-2 in our work was attractive and fell in the high side of the range of reported results in the open literature. Batch dark fermentation of agrowastes as practiced in our work could be useful for future biorefineries that generate biohydrogen as a first step and could influence the management of this type of agricultural wastes in Mexico and other countries and regions as well. (C) 2013 Elsevier Ltd. All rights reserved.
Recently, new solutions have arisen to promote bioenergy expansion, some of which meet the requirements of reliability, sustainability, and governance. In Brazil, the Sao Paulo state (SPS) is characterized by strong agro-industrial and livestock activities, which generates increasing residues in the last years with the potential to produce bioenergy and offer environmental and economic benefits. The Brazilian National Biofuel Policy (Renovabio) has been enhanced to seek sustainable development, encouraging new agribusiness research. Studies have shown that the sugarcane sector, a conventional ethanol and bioelectricity producer, has the greatest potential to produce biogas/biomethane, which can be maximized with the introduction of co-substrates regionally generated from corn, soy, orange, coffee, poultry, and swine. This overview, based on the main SPS agro-industrial and livestock residues, shows innovative alternatives for integrating anaerobic co-digestion (co-AD) processes through a regional strategy, by providing long-term revenues and greenhouse gas mitigation, which would also spread the discussion for National and International prospects. This study discusses logistical, political, and financial aspects, revealing a promising business model supported by public policies. However, its feasibility requires a real economic assessment with the inclusion of decarbonization credits, and political subsidies for biomethane as a biofuel under the Renovabio, which will facilitate its insertion into the agro-industry in the coming years.This article is categorized under:Policy and Economics > Energy TransitionsSustainable Energy > BioenergyClimate and Environment > Circular EconomyPolicy and Economics > Regional and International Strategies
Nine local (Guyana, South America) cross-bred, intact, growing, male goats (6 months old with mean (+/- SD) initial BW of 19.9 +/- 2.8 kg) were used in two metabolism trials. They were fed diets formulated to be iso-caloric with protein levels of 51, 76, 91, 108 and 127 g CP kg(-1) DM (Trial 1). Trial 2 goats were fed diets formulated to be iso-nitrogenous with energy density values of 7, 11, 12, and 14 MJ DE kg(-1) DM, Diets contained ground untreated sugarcane bagasse as the sole roughage source ranging from 253 to 540 g kg(-1) DM. Each diet was pelleted to minimise differences in physical-form and to prevent sorting and selection. The overall mean DMI values (+/-SD) for Trials 1 and 2 were 25.0 +/- 1.4 and 29.8 +/- 4.1 g kg(-1) BW, respectively. Trial 1 DMI showed a (P < 0.001) linear increase with N intake which accounted for 56\% of the variation of DMI and an increase of 33.1 g per unit increase of N, Both OM and DE intake increased (P < 0.05) with increasing dietary protein levels. However, when diets of varying energy levels (Trial 2) were fed only DE intake increased (P < 0.05), DMI increased to 11 MJ DE kg(-1) DM but fell when dietary energy was increased to 14 MJ DE kg(-1) DM. Digestibility of DM, OM and N showed (P < 0.001) differences, Urine N output and N retained increased (P < 0.01) with increasing dietary CP levels. This trend was not noted with increasing dietary energy levels. Urine N output decreased (P < 0.01) with increasing dietary energy levels. Diets with the lowest dietary energy level had less (P < 0.05) N retention. It was concluded that growing local goats can be fed a complete pelleted by-product based diet under confinement, and obtain adequate levels of DMI and nutrient utilisation.
Oil palm fronds (OPF) is the largest biomass which makes up to 70\% of the total residues generated from palm oil industry. Global production of oil palm fronds is estimated to be 250 million metric tonnes, MMT (wet weight) which can accommodate a sustainable production of 34.6 MMT of structural carbohydrates and 2 MMT of readily fermentable sugars per annum. The present study focused on the characterization of OPF composition by National Renewable Energy Laboratories (NREL) method. The results showed that OPF contained 57.6, 19.7 and 5.8\% of total structural carbohydrate, total lignin and ash content. The total structural carbohydrate mainly consisted of 42.8, 12.5 and 2.3\% of glucan, xylan and arabinan, respectively. HPLC analysis showed that OPF juice had 40 g/L of fermentable sugars consisting of glucose, sucrose, arabinose and fructose in the ratios of 62:31:4:4 with 0.2\% total suspended solid. A total of 25\% (w/w) of juice could be extracted from raw OPF using sugarcane juice extractor machine. Unlike OPF bagasse, the sugars in OPF juice were readily fermentable and could eliminate the costly pre-treatment. Fermentability test of OPF juice for succinic acid production using Actinobacillus succinogenes 130Z gave a final concentration up to 21 g/L after 60 h of anaerobic fermentation. This study also investigated the effect of CO2 availability, in the form of magnesium carbonate loading which was proven to have a direct effect on succinate production. A carbonate loading of 400 mmoVL in this study could produce lesser byproducts and four times higher succinic acid than the control (from 5 g/L without carbonate loading to 21 g/L). This is the first report focusing on the utilization of frond juice of Oil palm, the largest biomass from palm oil industry to act as an alternative, sustainable feedstock for the production of bio-succinic acid. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
Biochar has been suggested as a soil supplement to improve soil fertility and mitigate methane (CH4) emissions from rice farming. On the other side, the world is covered in microplastics (MPs), which are tiny pieces of degraded plastic. Studies have paid little attention to the combined biochar and soil contamination caused by MPs, particularly the mechanism of their interactions with CH4 emissions. In this study, a pot greenhouse experiment with a randomized complete block design (RCBD) was carried out to examine the impact of polystyrene (PS), sugarcane bagasse biochar (SBB), and their interaction (PS{*
Nitrogen-doped carbon with an ultra-high specific surface area and a hierarchically interconnected porous structure is synthesized in large scale from a green route, that is, the activation of bagasse via a one-step method using KOH and urea. KOH and urea play a synergistic effect for the enhancement of the specific surface area and the modification of pore size of the as-prepared material. Benefiting from the multiple synergistic roles originated from an ultra-high specific area (2905.4 m(2) g(-1)), a high porous volume (2.05 mL g(-1) with 75.6 vol\% micropores, which is an ideal proportion of micropores for obtaining high specific capacitance), a suitable nitrogen content (2.63 wt\%), and partial graphitization, the hierarchically interconnected porous N-doped carbon exhibits an excellent electrochemical performance with a high specific capacitance (350.8, 301.9, and 259.5 F g(-1) at 1.0 A g(-1) in acidic, alkaline, and neutral electrolytes, respectively), superior rate capability and excellent cycling stability (almost no capacitance loss up to 5000 cycles). Furthermore, the symmetric device assembled by this material achieves high energy densities of 39.1 and 23.5 Wh kg(-1) at power densities of 1.0 and 20 kW kg(-1), respectively, and exhibits an excellent long-term cycling stability (with capacitance retention above 95.0\% after 10 000 cycles).
The increasing consumption of fossil fuels has led to the development of alternative fuels for the future. Domestic biofuel production and the utilization of alternative fuels can decrease dependency on petroleum oil, reduce trade deficits, reduce air pollution and reduce carbon dioxide emission. Bioethanol is a renewable fuel produced by the fermentation of sugar which is derived from plants such as sugarcane or beet, maize, or cassava etc. However, bioethanol consumption in an engine is approximately 51\% higher than gasoline since the energy per unit volume of ethanol is 34\% lower than for gasoline. Bioethanol is an oxygenated fuel that contains 35\% oxygen, which can reduce particulate matter and NOx emissions caused by combustion of the fuel. Therefore, bioethanol-gasoline blends can significantly reduce petroleum use and GHG emission. In addition, utilization of lignocellulosic materials in bioethanol production is the most viable pathway from an environmental point of view. This paper reviews the current status and technologies involved in bioethanol production and the properties and engine performance from various biomass feedstocks which are the recommended sustainable alternative fuel in the future.
Rio Grande do Sul (RS) State edaphoclimatic conditions are suitable only to produce ethanol in small scale. However, small scale ethanol production (SSEP) was not proven to be feasible because of its lower process efficiency compared to large scale, and its environmental impacts were not assessed. The objective of this study is to evaluate SSEP through life cycle assessment (LCA) and energy efficiency analysis (EEA), showing potential scenarios of improvement in SSEP efficiency. Eco-Indicator 99 and CML 2 Baseline 2000 were the assessment methods, and the results demonstrated that nitrogen- and phosphorus-rich fertilizers, along with herbicides and limestone, were responsible for the highest environmental impacts in the agricultural sector, while the use of equipment and electricity had the highest impacts in the industrial sector. In the overall analysis, the industrial sector showed the highest environmental impacts. The SSEP global warming potential is 0.128 kg CO2eq/MJ(ethanol), almost 20 times higher than in large scale ethanol production, demonstrating the negative impact of lower SSEP efficiency. The EEA results were given in terms of net energy balance (NEB) and net energy ratio (NER) considering four scenarios (Cases 1 to 4). The agricultural sector showed high NER (19.59), while the industrial stage showed an NER of 0.20 and 2.08 for the baseline scenario (Case 1) and for the improved scenario (Case 4), respectively. The overall process showed a NER of 0.69 for Case 1, in which the bagasse was not considered as coproduct. When bagasse energy was taken into account, the NER rose to 4.82 (Case 4), showing the importance of coproducts in the process energy efficiency. The higher environmental impact of the industrial stage is an incentive to develop and use more efficient technologies in SSEP.
The strength integrity and chemical stability of porous alumina ceramics operating under extreme service conditions are of major importance in understanding their service behavior if they are to stand the test of time. In the present study, the effect of porosity and different pore former type on the mechanical strength and corrosion resistance properties of porous alumina ceramics have been studied. Given the potential of agricultural wastes as pore-forming agents (PFAs), a series of porous alumina ceramics (Al2O3-xPFA; x=5, 10, 15 and 20 wt\%) were successfully prepared from rice husk (RH) and sugarcane bagasse (SCB) through the powder metallurgy technique. Experimental results showed that the porosity (44-67\%) and the pore size (70-178 mu m) of porous alumina samples maintained a linear relationship with the PFA loading. Comprehensive mechanical strength characterization of the porous alumina samples was conducted not just as a function of porosity but also as a function of the different PFA type used. Overall, the mechanical properties showed an inverse relationship with the porosity as the developed porous alumina samples exhibited tensile and compressive strengths of 20.4-1.5 MPa and 179.5-10.9 MPa respectively. Moreover, higher strengths were observed in the SCB shaped samples up to the 15 wt\% PFA mark, while beyond this point, the silica peak observed in the XRD pattern of the RH shaped samples favored their relatively high strength. The corrosion resistance characterization of the porous alumina samples in hot 10 wt\% NaOH and 20 wt\% H2SO4 solutions was also investigated by considering sample formulations with 5-15 wt\% PFA addition. With increasing porosity, the mass loss range in RH and SCB shaped samples after corrosion in NaOH solution for 8 h were 1.25-3.6\% and 0.44-2.9\% respectively; on the other hand, after corrosion in H2SO4 solution for 8 h, the mass loss range in RH and SCB shaped samples were 0.62-1.5\% and 0.68-3.3\% respectively.
The increase of the global population has a negative impact to the environment due to the direct correlation between the amount of solid waste generated and the population growth. In order to create a more sustainable future, an adequate waste management system is necessary. Utilisation of biomass that have potential to be converted into various forms of valuable products (i.e. energy, biochemical and value-added products) is a promising way to deal with the increasing amount of agriculture residues. Therefore, it is suggested to develop a multi-biomass corridor in order to promote a global sustainable development of renewable energy. However, this large-scale problem normally consists of a huge number of variables (large set of possible locations of processing hub, large set of operating units and large set of material involved). This will lead to a longer computational duration due to the high complexity of the network. In order to address this issue, a novel ``Decomposition Approach{''
Population growth has increased the demand for food, intensifying land use for agricultural activities. At the same time, soils have lost their fertility due to the uncontrolled use of agrochemicals, harmful practices, and climate change. In Panama, 27 \% of the soil is not available for agriculture. These regions correspond to the sectors with the highest agricultural production in the country. Therefore, various methods have been investigated to improve soil fertility, such as using biochar as a soil amendment and fertilizer. Biochar is a carbonaceous material produced by the thermochemical decomposition of organic materials. Biomaterial production from fast-growing plants has gained interest over the years. Furthermore, wild sugarcane (Saccharum spontaneum L.) is a tall, fast-growing, invasive grass in Panama that shows biomass production potential. Recent reports indicate that this plant could be converted into biochar or carbon, producing a biomaterials source for soil remediation. This work aims to evaluate the potential of wild sugarcane biochar as a soil amendment. The samples maintained a pH > 9.0 and an ash percentage of approximately 20 \%. At 8 L/min, a higher proportion of nutrients such as Mn, Fe, Mg, and P was obtained with 161 mg/kg, 310 mg/kg, 0.279 \%, and 0.461 \%, respectively. At 12 L/min, organic carbon was higher, with 61.32 \%. The resulting biochar has essential characteristics and properties that could be used in soil improvement.
This study aims to quantify the environmentally sustainable and economically feasible potentials of agricultural and agro-industrial residues to generate electricity via direct combustion in centralised power plants in Brazil. Further, the energy savings and greenhouse gas (GHG) reduction potential of replacing natural gas-based electricity by bioenergy have been assessed. To this end, a methodology has been developed based on an integrated evaluation, incorporating statistical and geographical information system (GIS)-based analysis, and a life-cycle-assessment approach. Results reveal that the environmentally sustainable generation potential is nearly 141 TWh/year, mainly concentrated in the South, Southeast, and Midwest regions of the country. Sugarcane, soybean and maize crop residues are the major feedstocks for available bioenergy. On the other hand, the economic potential is far lower, accounting to 39 TWh/year. The total GHG mitigation is nearly 18 million tonne CO(2)e and could reach 64 million tonne CO(2)e yearly, if the technical potential is considered. The gap between technical and economic potentials implies that constraints to bioenergy are not related to a lack of resources, but rather associated to economic, logistical, regulatory and political barriers. (C) 2015 Elsevier Ltd. All rights reserved.
To reduce the distillation costs of cellulosic ethanol, it is necessary to produce high sugar titers in the enzymatic saccharification step. To obtain high sugar titers, high biomass loadings of lignocellulose are necessary. In this study, to overcome the low saccharification yields and the low operability of high biomass loadings, a fed-batch saccharification process was developed using an enzyme reactor that was designed and built in-house. After optimizing the cellulase and biomass feeding profiles and the agitation speed, 132.6 g/L glucose and 76.0\% theoretical maximum glucose were obtained from the 60 h saccharification of maleic acid-pretreated rice straw at a 30\% (w/v) solids loading with 15 filter paper units (FPU) of Cellic CTec2/g glucan. This study demonstrated that through the proper optimization of fed-batch saccharification, both high sugar titers and high saccharification yields are possible, even with using the high solids loading (i.e., >= 30\%) with the moderate enzyme loading (i.e., <15 FPU/g glucan). These results could be contributed to improving economic feasibility of the high solids saccharification process in cellulosic fuel and chemical production.
This study investigated the use of glycerol-fatty acid sodium soap mixtures to delignify woody biomass as a model for utilization of crude glycerol by-product from biodiesel manufacture. Lignin-bearing glycerol was also produced. Delignification was carried out using glycerol mixed with sodium salts of laurate, stearate, oleate, or linoleate at 100-250 degrees C for 0.5-3h. Oak, beech, bamboo, and rice straw were easily delignified by 20\% sodium oleate dissolved in glycerol at around 150 degrees C for 1h. For softwood (Japanese cedar and spruce), delignification did not occur below 200 degrees C. However, the lignin content decreased from 37.5\% in untreated Japanese cedar to 10.6\% and from 29.4\% in untreated spruce to 11.2\% by treatment at 250 degrees C. Japanese cedar was not delignified in glycerol mixtures with oleic acid or sodium acetate. It is suggested that the surfactant activity of soap assists delignification, but the alkaline action of sodium acetate was not effective. Enzymatic saccharification of delignified Japanese cedar (9.3\% lignin) and oak (3.6\% lignin) samples gave glucose yields of 0.55-0.67g/g after 72h and these yields were comparable with that from pure cellulose (0.77g/g). Lignin dissolution also increased the calorific value of the collected glycerol fraction from 20 to 25MJ/kg. The results suggest that a waste-free delignification method can be achieved based on the combined processes of biodiesel and bioethanol production.
To gain an in-depth understanding of AAEMs (alkali and alkaline earth metals) transformation during biomass gasification, a fixed-bed reactor is built to simulate the CO2 gasification at 500-900 degrees C. The influences of biomass species, gasification temperature, and particle size are examined. The results show that the AAEMs release follow a sequence of candlenut wood > wheat straw > corn stalk. The alkali metals mainly appear as water-soluble inorganic salts and the contents are more than 80\%. K mainly occurs as KCl and KClO4. At higher temperatures, K could combine with Al and Si to form K(AlSi3)O8. For candlenut wood, a bigger particle size is beneficial to the transformation of water-soluble K to organic K. For candlenut wood with centimeter-scale, K mainly occurs as organic K in the biochar during 600-700 degrees C. When the gasification is carried out at 700 degrees C, K concentrates at the center and its content is even higher than that on the outer surface. While for biochar samples obtained from gasification at 600 and 900 degrees C, the K content at the center is lower than that on the outer surface due to the continuous outward transformation of K from the central biochar.
Bioethanol is one of the most significant renewable fuels. The major sources of bioethanol production are food crops such as corn, sugarcane, rice, wheat and sugar beet. However, utilization of food crops to produce bioethanol could affect the food sources and disrupt the food to population ratio. To overcome these issues, the utilization of lignocellulosic materials such as wheat straw, grass and crop residues to produce bioethanol has been developed for second-generation fuel, since those resources are abundant, cheap and renewable. Napier Pakchong 1 grass (NPG) residue is a lignocellulosic waste obtained from the process of biogas production that can be used as an alternative material for bioethanol production. This research aims to study on the potential of fermentable sugar production from NPG residue. The materials were pretreated with different concentrations of sodium hydroxide (NaOH), followed by enzymatic hydrolysis for saccharification. The results suggested that pretreatment with 3.0\% (w/v) NaOH solution at 121 degrees C for 60 minutes provided the highest lignin removal of 86.1\% (w/w) and enriched cellulose fraction from 36.4 to 75.6\% (w/w). The enzymatic hydrolysis was conducted by varying enzyme loading volume and total solid contents (TS) at pH 4.8, 50 degrees C for 72 h. The hydrolysis with enzyme loading volume of 2.0 ml/g of substrate and 10\% (w/v) of TS were optimal for saccharification giving the reducing sugar yield of 768 mg/g of pretreated biomass or equal to 64 g/L and glucose yield of 522 mg/g of pretreated biomass or equal to 43 g/L. The reducing sugar will be used as a starting material for yeast to produce bioethanol. (C) 2016 The Authors. Published by Elsevier Ltd.
The application of biochar to soil combined with synthetic fertilizers has been proposed for enhancing N availability to plants and crop yields while reducing nitrous oxide (N2O) emissions. However, little is known about those interactions for tropical soils. Thus, this study evaluated the effects of sugarcane straw biochar on tropical soil attributes, crop productivity, N2O emissions and N use efficiency. It was conducted a greenhouse pot experiment with wheat cultivation using a(15)N-labelled source ((NH4NO3)-N-15). The treatments evaluated were: Soil, with N, no biochar; Soil, with N and biochar at rates equivalent to 0.4\%, 0.8\% and 1.9\% (w/w); and a control (soil only). Increasing biochar amendments decreased cumulative N2O emissions by 71\% compared to the fertilized, no-biochar soil. Moreover, increasing biochar rates to soil increased available Pup to 30\% and led to 8-fold higher exchangeable K+ concentrations. Grain yield and shoot biomass increased by 27 and 16\%, respectively, with the rate of 1.9\% biochar to soil, which also resulted in higher tillering and number of heads compared to fertilized, no-biochar soil. The amount of 15 N in grains was 28\% higher with 0.8 and 1.9\% of biochar compared to no-biochar soil, which correspond to 25\% of the total 15 N-labelled fertilizer applied to soil. The 15 N loss by volatilization did not differ between treatments. Nevertheless, the biochar amended soils produced less N2O than the no-biochar treatment, indicating that biochar amendment to tropical soil led to gaseous N losses in forms other than N2O. The application of biochar to soil improved N utilization and the efficiency with which N is acquired by the plants and converted to grain yield, thereby enhancing crop performance, while simultaneously reducing N2O emissions from N fertilization, thus mitigating GHG emissions to the atmosphere under tropical conditions.
Long-term intensive rice monoculture, triple rice cultivation (rice crops are cultivated three times per year) in the Mekong Delta, Vietnam, causes a reduction in topsoil quality. Rotating rice with an upland crop in a tropical paddy field may improve the soil physicochemical properties but effects on the soil nematode community are unknown. This study was conducted in a triple rice field to evaluate the responses of the nematode community to a crop rotation (the first rice in a year was replaced with sesame and soybean, and the second and third crops were rice) and to organic amendment. The experiment was based on a split-plot design with two factors that were crops (main factor, n = 3) and compost amendment (sub-factor, n = 3). The crops were rice, soybean, and sesame and the sub-factors were cow manure plus rice straw compost, sugarcane compost, and no amendment. Soil samples were taken at harvest of the first crops in topsoil (0-10 cm) and subsoil (10-20 cm) in 2017 and 2018. In 2018, the abundance of free-living nematodes (FLN), which were dominated by bacterivores and fungivores, was greater in upland crops, while that of plant-parasitic nematodes (PPN) was greater in paddy rice. In particular, the density of the most predominant PPN genus, Hirschmanniella, was lower in upland crops than in paddy rice. Cultivation of sesame also reduced the number of the second predominant PPN genus, Bitylenchus, resulted in an increase in the ratio of the free-living to plant-parasitic nematodes. The diversity evenness index (J), Shannon-Wiener (H') and Hill's indices increased in upland crops compared to those in rice fields in 2018. Crop rotation with sesame or soybean in a paddy field enhanced abundance and biodiversity of FLN and suppressed PPN and thus can be proposed for agricultural sustainability.
Arsenic (As) and lead (Pb) are potentially toxic elements capable of developing several diseases in human beings such as cancer. Several adsorbent materials, including biochars, have been adopted as alternative measures designed to reduce the availability of As and Pb in water. The retention capacity of potentially toxic elements in biochars varies according to time, feedstock, and the pyrolysis temperature to produce the biochar. Our objectives in this study were to evaluate i) the aging effect of sugarcane straw pyrolyzed biochars at 350 (BC350), 550 (BC550), and 750 degrees C (BC750) and their ability to immobilize As and Pb; and ii) how the pyrolysis temperature and biochar aging alter the carbon content and quality of the solution and sediment. Biochars were applied at 5\% (w/w), and their aging together with As and Pb immobilization effects were evaluated every 45 days over a total period of 180 days. The results were obtained using visible ultraviolet spectroscopy and diffuse reflectance infrared Fourier transform spectroscopy combined with physical fractionation of organic matter and multivariate statistics. The groups formed in the Principal Component Analysis indicated that the change in the availability of As and Pb was related to the aging of the biochar and the temporal changes in the content and quality of organic carbon in the sediment and solution. The pyrolysis temperature was a key factor in the (im)mobilization capacity of As and Pb during the aging of the biochar. The increase in polysaccharides and organic matter associated with the particulate fraction can enhance the release of As in solution (24\%). Increasing the fraction of organic matter associated with minerals reduced the availability of Pb by 58\%. These findings may provide new insights into understanding the dynamics of organic matter and its role in the immobilization of As and Pb during biochar aging. (c) 2021 Elsevier B.V. All rights reserved.
Water contamination by arsenic (As) affects millions of people around the world, making techniques to immobilize or remove this contaminant a pressing societal need. Biochar and iron (oxyhydr)oxides {[
As the Thai economy grew rapidly after 1985, agriculture became more intensive through the increasing use of chemical fertilizer and mechanization. This study aimed to analyze the nitrogen (N) cycle related to agricultural activities in Khon Kaen Province in Thailand during 1990-1992 and 2000-2002, and on the changes in utilization of local organic resources and the N load to the environment. A model of the N cycle was constructed including compartments for farmland, crop yield, crop residue, food factory, livestock, humans, market, hydrosphere and atmosphere. N flows among the compartments in the model were estimated from data derived from Thai agricultural statistics, related reports and journal articles, interviews with farmers and food factory staff, field observation and information from Thai experts. N flow through livestock declined because of a decrease in the number of buffalo raised, which reduced the production of animal manure. N returned to farmland in crop residues increased because sugarcane cultivation, and crop residues, increased and the burning of rice straw decreased. An increase in chemical fertilizer application increased N input to farmland for crop production. N balance in farmland changed from -27 kg ha(-1) year(-1) in 1990-1992 to +6 kg ha(-1) year(-1) in 2000-2002, which improved soil N depletion. Because N leaching and erosion from farmland were low, water pollution in farmland is expected to be low. Human waste was not used or treated, and water pollution from human waste would be expected in housing areas. Analysis of indices of the N cycle showed that the stock of soil N in farmland supported agricultural production in 1990-1992, and that N inflow from outside the area (chemical fertilizer) supported agricultural production in 2000-2002. However, efficiency of N use for agricultural production did not improve.
Cellulose succinate, which was used for efficient adsorption of heavy metals, was directly prepared by mechanical activation (MA)-assisted solid-phase synthesis in a stirring ball mill with bagasse pulp and succinic acid as materials without the use of organic co-reagents and solvents. FTIR, XRD, SEM, and specific surface area analysis were used to characterize the structural characteristics of cellulose succinate. Furthermore, the effects of different degrees of esterification of modified cellulose on the adsorption of Cd2+ and Pb2+ were investigated. A surface charge characteristic was used to prove the effect of pH on the adsorption ability of cellulose succinate. It was found that the adsorption kinetics of Cd2+ and Pb2+ onto cellulose succinate fitted well with the pseudo-second-order model. The adsorption of Cd2+ and Pb2+ onto cellulose succinate was well described by the monolayer adsorption of the Langmuir isotherm model rather than the multilayer adsorption of the Freundlich isotherm model. The E values for the adsorption of Cd2+ and Pb2+ by cellulose succinate calculated by the DubininRadushkevich equation were all in the range of 8-16 kJ mol(-1), suggesting that the adsorption process mainly proceeded by ion exchange. The MA-assisted solid-phase synthesis method can produce efficient and environmental-friendly adsorbents.
Background: Phytic acid acts as anti-nutritional factor in food and feed ingredients for monogastric animals as they lack phytases. Objective: Phytase production by Bacillus subtilis subsp. subtilis JJBS250 was studied in solid-s-tate fermentation and its applicability in dephytinization of food. Methods: Bacterial culture was grown in solid state fermentation using wheat bran and various cul-ture conditions were optimized using `One variable at a time' (OVAT) approach. Effects of differ-ent substrates (wheat bran, wheat straw, sugarcane bagasse), incubation time (24, 48, 72 and 96 h), incubation temperatures (25, 30, 35 and 40oc), pH (4.0, 5.0, 6.0, 7.0 and 8.0) and moisture content (1:1.5, 1:2.0, 1:2.5 and 1:3) were studied on phytase production. Bacterial phytase was used in de-phytinization of food samples. Results: Optimization of phytase production was studied in solid state fermentation (SSF) using `One variable at a time' (OVAT) approach. Bacillus subtilis subsp. subtilis JJBS250 grew well in various agroresidues in SSF and secreted high enzyme titres using wheat bran at 30oc and pH 5.0 after incubation time of 48 h with substrate to moisture ratio of 1:3. Glucose and ammonium sul-phate supplementation to wheat bran further enhanced phytase production in SSF. Optimization of phytase production resulted in 2.4-fold improvement in phytase production in solid state fermenta-tion. The enzyme resulted in dephytinization of wheat and rice flours with concomitant release of inorganic phosphate, reducing sugar and soluble protein. Conclusion: Optimization resulted in 2.34-fold enhancement in phytase production by bacterial culture that showed dephytinization of food ingredients with concomitant release of nutritional components. Therefore, phytase of B. subtilis subsp. subtilis JJBS250 could find application in im-proving nutritional quality of food and feed of monogastric animals.
The use of uncontrolled fire by human beings associated with climate conditions favorable to burning has caused social, economic and environmental damage in different parts of the world. The objective of the present study was to evaluate the variations in the occurrence of fire in Southern Region of Brazil caused by the seasonal characteristics of the years. We also sought to highlight the vegetation coverings most affected by fires within each year assessed and among the different ENSO events. Fire products from the MODIS were associated with meteorological elements and vegetation cover data, in addition to evaluating Carbon emission data made available by GFED. The correlation between the meteorological elements and fire was obtained by Spearman's non-parametric approach. Additionally, Mann Kendall's statistical test was performed with the harvested area extensions of three temporary agricultural crops (Maize, Soybean and Sugarcane) over 28 years. Fire in Southern Brazil correlates mainly with reduced rainfall and relative air humidity together with increased atmospheric pressure and increased wind speed. The periods under the effect of the cold phase of the phenomenon (La Nina) presented 26\% to 114\% more fire foci than those under the hot phase (El Nino). La Ninas also showed 7\% to 77\% more burned area than El Ninos. La Nina events emitted more carbon into the atmosphere than El Nino, and the greatest difference was observed between La Nina 2007/2008 (1.51 Tg) and El Nino 2015 (0.65 Tg). The vegetation covers most affected by the fire were those related to agricultural activity. Mann Kendall's statistics indicated that Sugarcane, an agricultural crop with flammable straw, showed a tendency to expand in the state of Parana'. between 1990 and 2018. Infra and inter-annual atmospheric variations and the mosaic of different vegetation covers determined the fire pattern in the study area over the period studied.
Degradation of physical, chemical and biological properties of soils in sub-Saharan Africa mainly results from little or no organic resource application coupled with sub-optimal fertilizer application. A study was conducted over three seasons, from March 2010 to August 2011, to evaluate potential of six organic materials (bagasse, cow manure, filtermud, maize stover, sugarcane straw and Tithonia diversifolia) for compost production and their influence on maize yield and soil fauna diversity. Treatments comprised of the six composts, commercial fertilizer and no-input control, laid out in randomized complete block design in four replicates. Soil macrofauna were collected using soil monolith method. Data obtained were subjected to analysis of variance (ANOVA) using GENSTAT whereas differences were evaluated using Fisher's least significant difference (LSD). Correlation between macrofauna and soil chemical properties was done using CANOCO 3.1. The ANOVA showed significantly higher N and P on filtermud (10.0 g N kg(-1) and 979 mg P kg(-1)) and T. diversifolia (9.6 g N kg(-1) and 614 mg P kg(-1)) composts. Generally, amending soils with composts increased C, N and P of the soil by 90 \%, 29 \% and 20 \%, respectively, while fertilizer treated plots recorded 42 \%, 4 \% and 110 \% increase in C, N and P, respectively. Control plots recorded 25 \% increase in C, but 15 \% and 50 \% decline in N and P, respectively. Maize yields were highest in fertilizer (4.4 Mg ha(-1)), followed by composts (2.8 Mg ha(-1)) and lowest in control plots (1.4 Mg ha(-1)). Soil macrofauna responded positively to addition of composts. Isopterans, Oligochaeta and Hymenopterans dominated the sites constituting 44 \%, 26 \% and 17 \%, respectively of all the macrofauna. Relationships between macrofauna and soil chemical properties were positively significant. Results of this study demonstrate the potential of composts in improving soil biodiversity and crop productivity.
Saccharification of lignocellulose is prerequisite for the biorefinery. Clostridium thermocellum is a promising candidate for the hydrolysis of lignocellulose. A study on the saccharification by Clostridium thermocellum combined with surfactant and cellulase addition was investigated. The reducing sugars content increased with increasing substrate loading in the fermentation of C. thermocllum with isooctyl alcohol polyoxyethylene ether (IAPE) addition. Based on IAPE addition, the glucose content of two-step saccharification was higher than that of the batch saccharification. Besides, the addition of IAPE and Triton X-100 had the same effect on saccharification. The saccharification performance was related to the substrate, especially the lignin content. For the fed batch hydrolysis of 20 \% (w/v) rice straw pretreated by hydrogen peroxide-acetic acid (HPAC), 66.9 g/L glucose and 19.5 g/L xylose were obtained by using C. thermocellum DSM 1313 and 1 FPU/g substrate cellulase with 0.1 \% (w/v) IAPE addition, and the glucose and xylose yield reached 63.2 \% and 37.4 \% respectively.
In this study, esterification of oleic acid with methanol using solid acid catalysts synthesised from different waste biomasses (bamboo, wheat straw, and peanut shells) using the carbonisation-sulphonation method was inves-tigated. The results showed that biomass with higher lignin content had a lower optimum carbonisation tem-perature and the corresponding catalyst contained more acidic groups. All three catalysts catalyzed esterification reactions under optimum reaction conditions (10 wt\% catalyst loading, 8:1 methanol/oleic acid, at 75 degrees C for 8 h) with >96\% conversion. The oleic acid conversion decreased with catalyst cycles, reaching approximately 80\% after four cycles. In addition to the leaching of active groups during the reaction, the reaction of the sulphonic acid on the catalyst surface with excess methanol (i.e., sulphonic ester formation) is an important cause of catalyst deactivation. The high concentration of sulphonic acid groups on the catalyst surface was the major cause of sulphonic ester formation during esterification. Therefore, reducing the concentration of sulphonic acid groups by increasing the catalyst volume and specific surface area is an effective way to avoid reduction in the catalyst activity while maintaining a constant total number of sulphonic acid groups.
This work describes the fructooligosaccharides (FOS) and beta-fructofuranosidase (FFase) production from sucrose (200g/ll) by Aspergillus japonicus ATCC 20236 immobilized on different lignocellulosic materials including brewer's spent grain, wheat straw, corn cobs, coffee husks, cork oak, and loofa sponge. Transfructosylating (U(t)) and hydrolyzing (U(h)) activities of FFase were also determined. The FOS production and FFase activity ranged from 128.35 to 138.73 g/l, and 26.83 to 44.81 U/ml, respectively, for cells immobilized in the different carriers. Corn cobs was the best support material since gave the highest results of microorganism immobilization (1.49 g/g carrier), FOS and FFase production, with FOS productivity (6.61 g/l h) and yield (0.66g/g based on total substrate; 0.73 g/g based on consumed substrate) higher than those obtained by free cells system. Moreover, the ratio U(t)/U(h), of FFase, parameter of importance for elevated FOS production, was greater for cells immobilized in corn cobs than for free cells. Such results demonstrated that corn cobs can be successfully used as carrier for immobilization of the fungus A. japonicus, for the production of FOS and FFase. (C) 2009 Elsevier B.V. All rights reserved.
The quantification of silicon (Si) in plant samples is being requested more frequently, especially in agricultural laboratories associated with the determination of nutritional requirements of sugarcane (Saccharum officinarum L.) and rice (Oryza sativa L.). The analysis of plant material for Si can be protracted, especially if laboratories do not have access to X-ray flourescence (XRF) instrumentation and large numbers of samples are involved. A simplified procedure using equipment considered standard in most agricultural laboratories is reported. Dry, ground plant material is subjected to nitric acid/peroxide oxidation in a low-pressure laboratory microwave digestion system. The hydrated silica liberated from the organic matrix is dissolved in a small volume of sodium hydroxide solution also using the microwave digestion system. Silicon is measured by inductively coupled plasma atomic emission spectrometry (ICP-AES). This method gives results that are linearly correlated with the much slower conventional techniques and avoids using hazardous chemicals (hydrofluoric acid) sometimes employed in other microwave methods.
A novel, low-cost, and environmentally friendly method of synthesising biogenic platinum nanoparticles (Pt NPs) was employed using biomass sugar cane (Saccharum officinarum L.) bagasse extract (SBE) as the reducing agent. Pt NPs derived from this biosynthesis route were thoroughly characterised by High-resolution transmission electron microscopy (HRTEM), Field emission scanning electron microscopy (FESEM), Energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) analysis. Due to the involvement of bio-reductive metabolites during biosynthesis, their metabolite profiles were identified using gas chromatography-mass spectrometry (GC-MS) and in-vitro antioxidant activities. Eleven major metabolite compounds from the SBE classified as phenol, pyrazole, furan, pyran, epoxide, long-chain fatty acid, sterol glycoside, and mixed oxygenated compounds may be responsible for the bio-reduction process. The biogenic Pt NPs endowed a high antioxidant property that can scavenge DPPH free radicals by 81.9\%, with an inhibitory effect (IC50) of 37.60 mu g/mL and ferric reducing antioxidant power assay (FRAP) of 57.58 mu mol FeSO4/g. Furthermore, the biogenic Pt NPs deliver superior electrocatalytic activity in methanol oxidation reactions with tunable Pt ions concentration, PtCl62-, from 0.5 to 1.75 mM, with a maximum electrochemical active surface area (ECSA) of 93.41 m2 g-1 and a mass activity/specific activity of 581.50 mA mg-1/1.25 mA cm- 2 demonstrates that green chemical reduction using plant extracts is a viable method for producing biogenic Pt NPs for energy conversion and health applications, owing to its improved electrocatalytic activity and profound antioxidant properties.
Bioethanol is the most widely used alternative transportation fuel to petrol. Bioethanol is considered a clean, renewable, and environmentally friendly fuel that can contribute to climate change mitigation, decreased environmental pollution, and enhanced energy security. Commercial bioethanol production is based on traditional agricultural crops such as corn, sugarcane, and sugarbeet, primarily used as food and feed. In order to meet the growing demand for this fuel and decrease competition in the food and biofuel sectors for the same feedstock, other raw materials and process technologies have been intensively studied. Lignocellulosic biomass is one of the most abundant renewable resources, with it being rich in compounds that could be processed into energy, transportation fuels, various chemical compounds, and diverse materials. Bioethanol production from lignocellulosic biomass has received substantial attention in recent decades. This review gives an overview of bioethanol production steps from lignocellulosic biomass and challenges in the production process. The following aspects of bioethanol production are covered here, including pretreatment methods, process strategies, strain development, ethanol isolation and purification, and technical hurdles.
This study investigated the xylanases produced by Trichoderma piluliferum and T. viride. These enzymes were characterized and used as additives in bovine diet. The fungus T. piluliferum was a more efficient producer of xylanase (301 U g(-1) dry substrate) when grown on wheat bran, with 75 or 80\% moisture for 96 h. The optimum pH of the enzyme produced by T. piluliferum was 4.5, obtaining as the optimum temperature 50 degrees C. The enzyme was stable at a wide pH range (3.0-10.0), and it remained stable for 1 h at 40 degrees C. The best culture parameters for the cultivation of T. viride (671 U g(-1) dry substrate) were as follows: wheat bran as substrate, 65, 70 and 75\% initial moisture, and 48 h cultivation time. The optimum pH and temperature for the xylanase produced by this fungus were 6.0 and 45 degrees C, respectively, and the enzyme was stable at a wide pH range (3.0-10.0), maintaining its activity after 1 h at 40 degrees C. Both the enzyme extracts produced were effective at increasing digestibility of Tifton 185 hay, sugarcane silage, and corn silage. The enzymatic extracts proved promising for xylooligosaccharides production and showed low cellulase activity, indicating potential for application in biobleaching processes of cellulose pulp and paper.
A high performance anion exchange chromatography (HPAEC) isotopic ratio mass spectrometry (IRMS) method was developed for amino sugar-specific delta C-13 analysis in plant hydrolysates. The HPAEC-IRMS method provided good validation parameters and the amino sugar concentrations were similar to those obtained by reversed phase (RP) high performance liquid chromatography (HPLC) and fluorescence (Fl) detection. The limit of quantification (LOQ) was 150 mu mol l(-1). This optimised HPAEC-IRMS method opens up the possibility of a glucosamine (GlcN) specific delta C-13 analysis in plant material. Thus, it was possible to determine the delta C-13 values in newly formed fungal GlcN for the first time. The formation and turnover of saprotrophic fungi was investigated by using the improved HPAEC-IRMS method for GlcN-specific delta C-13 analysis. The cultivation of saprotrophic fungi (Lentinula edodes and Pleurotus species) in beech wood mixed with maize or wheat straw showed the preferred formation of fungal biomass from maize-derived (80\%) rather than from beech wood-derived C. The results indicate a faster formation of fungal biomass from maize than from wheat straw as co-substrate. (c) 2012 Elsevier Ltd and The British Mycological Society. All rights reserved.
Novel laccase-producing thermo-tolerant organisms were identified and its culture conditions optimized for effective delignification. Forty-three isolates were screened for ligninolytic activity, out of which six isolates with higher laccase specific activity (3.27, 5.49, 2.26, 4.54, 4.61, and 4.73 U mg-(1) protein) were selected for further analysis. Maximum enzyme production of 450 U/mu L was obtained after 120 hours of incubation, at 46 degrees C and pH 6.0. Erianthus bagasse digested with crude enzymes was studied for their structural modifications. The SEM analysis showed cavities (1.28 to 2.56 mu m) indicating the disintegration of lignin molecules while the FT-IR showed peaks at 1509 cm(-1), 1725 cm(-1), and 2894 cm(-1) indicating the breakdown of lignin, hemicellulose, and cellulose moieties, respectively. The GC-MS analysis generated derivatives of syringyl and hydroxyphenyl lignin. Sequence analysis of the isolate showed that the isolate S2 is affiliated to A. caespitosus and its purified laccase showed a specific enzyme activity of 7.9 to 19.2 U/mg of protein. Our results suggest that Aspergillus caespitosus S2 has the highest potential for Erianthus delignification. Aspergillus caespitosus and its system biology generated from this study might be beneficial for bio-refinery applications.
Thermohydrolysis at low temperatures achieves lower conversion compared to high temperatures. However, the process consumes less energy. We tried to make this pretreatment process more efficient by adding triticale grist to the fermentation and use the positive effect of the protein content and the increased ethanol concentration. The concept is made for rebuild of grain distilleries and reuse of the large equipment. The concept was evaluated for several crops with an attempt to crop diversity in the fields. This work presents thermohydrolysis (155 degrees C, 45 min) with subsequent steam explosion combined with an enzymatic hydrolysis and the addition of triticale grist in the fermentation process. All substrates achieved improved cellulose hydrolysis, except for the silages. Over 90\% of the cellulose in hemp straw and Jerusalem artichoke stalks was converted to glucose. Analysis for inhibitors showed high amounts of organic acids solely in Jerusalem artichoke mashes, corn and wild plant silage. The chosen conditions are suitable for a great variety of crops, also as intercrop scenario. However, silages need pH adjustment. The high loads of organic acids clearly suppress amylase activity, but cellulase activity seems to be unaffected. The switch to mixed first and second generation ethanol production in distilleries is possible.
Background Cellulase adsorbed on cellulose is productive and helpful to produce reducing sugars in enzymatic hydrolysis of lignocellulose; however, cellulase adsorbed on lignin is non-productive. Increasing productive adsorption of cellulase on cellulose would be beneficial in improving enzymatic hydrolysis. Adding lignin that was more hydrophilic in hydrolysis system could increase productive adsorption and promote hydrolysis. However, the effect mechanism is still worth exploring further. In this study, lignosulfonate (LS), a type of hydrophilic lignin, was used to study its effect on cellulosic hydrolysis. Results The effect of LS on the enzymatic hydrolysis of pure cellulose (Avicel) and lignocellulose {[
Sugarcane spent wash generates waste at a large scale that impacts the environment, hence the classic waste reuse technology needs to be implemented. An integrated approach of spent wash and microalgae cultivation to produce biodiesel has gained momentum in recent times. However, the microalgae technology lacks the func-tional utilization of de-oiled microalgae biomass (DOB). This study proposed the development of a microalgae-based advanced process for distillery spent wash treatment, biomass recovery for biodiesel and utilizing algal residue as a step towards waste management. A novel microalga Coelastrella sp KJ-04 grown in distillery spent wash represented with high biomass (4.61g/L) and lipid production (3.6 g/L). The significant reduction in Chemical Oxygen Demand (COD, 49.3\%), Total Nitrogen (TN, 49.7\%), Total Phosphorous (TP, 21.8\%), Total Organic Carbon (TOC, 40.2\%), Total Sulphur (S, 37.2\%) and Potassium (K, 42.5\%) were achieved in spent wash. The extracted lipids of Coelastrella sp KJ-04 were converted to Fatty acid methyl ester (FAME) and examined by Gas chromatography-mass spectrometry (GC-MS) to observe the suitability for biodiesel prospect. The de-oiled biomass (DOB) was utilized for the synthesis of Cellulose nanofibers (CNF), purified and estimated with a diameter ranging between 20 and 27 nm. The crystalline structure and functional group of CNF were analyzed by X-ray diffraction (XRD) and Fourier Transform infrared spectroscopy (FTIR). The unprecedented work demon-strated the microalgae biorefinery approach for spent wash remediation, biodiesel synthesis and simultaneous production of biodegradable CNF from algal residue to support waste-free technology. In future, CNF can be reinforced into material for concrete as it could be the smart alternative to replace synthetic cement plastics.
In this work, biomass-derived carbon-supported (Ag/P@BC) Ag composites were prepared and used to remove pollutants (rhodamine B, RhB) under visible light irradiation. Corn straw was chosen as the source of biomass-derived carbon, and the optimal calcination temperature was set to 600 degrees C. When AgNO3 with an impregnation concentration of 1.0 mM 1Ag/P@BC (1Ag/P@BC) and RhB with an initial concentration of 320 mg L-1 were added, RhB removal exceeded 93\%, and the removal capacity reached 1536.71 mg g(-1) after adsorption and photocatalysis for 60 min. The maximum capacity of 3141.73 mg g(-1) was achieved for RhB removal over 1Ag/ P@BC. Although 1Ag/P@BC presents the greatest removal capacity (including adsorption-photocatalysis), 0.1Ag/P@BC had the lowest bandgap energy (2.14 eV) and the highest photocatalytic activity. Owing to its large specific surface area (1655.02 m(2) g(-1)), 0.1Ag/P@BC had a photodegradation rate 33 times that of pure BC, as determined from kinetic studies. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and high-resolution transmission electron microscopy (HRTEM) analyses revealed that both Ag and Ag3PO4 existed in the composites and that an electronic interaction occurred between P and O, which was attributed to Ag loading. Moreover, the composites have good stability and broad applicability in acidic, neutral and alkaline conditions as well as in tap water. Based on the photoluminescence (PL), electrochemical impedance spectroscopy (EIS), electron spin resonance (ESR) and trapping experiment results, an in-depth analysis of the underlying mechanism for the adsorption-photocatalysis process was also conducted.
This trial aimed to evaluate the effects of increasing levels of raw soybeans on milk yield, composition, and fatty acid profile in ewes, and their lambs performance. Fifty-six Santa Ines ewes (63.9 +/- 0.76 kg BW) were assigned to a randomized complete block design to receive one of the four diets containing 0 (CONT), 70, 140 or 210 g/kg DM of raw soybeans. Isonitrogenous diets (150g/kg DM of CP) were composed of 400 g/kg DM of in natura sugarcane bagasse as roughage source and 600?g/kg DM of concentrate. The experiment lasted from 14 to 56 days of lactation. Once a week the ewes were separated from their lambs and milked mechanically. DMI (1.3, 1.3, 1.5 and 1.2 kg/day) and milk yield (1.0, 1.1, 1.1 and 1.0 kg/day) presented a quadratic effect (P < 0.05) including 0, 70, 140 or 210 g/kg DM of raw soybeans on diets, respectively. However, milk yield corrected for fat or fat and protein, as well as content of milk fat, protein, lactose and total solids did not differ. Short (C4-C12) and medium (C14-C16) chain fatty acids decreased, whereas long-chain (C = 17) fatty acids increased linearly (P < 0.05) with raw soybeans supply. Conjugated linoleic acid (CLA; cis-9 trans-11 and trans-10 cis-12) increased (P = 0.01) and the atherogenicity index decreased linearly (P < 0.05) with increasing levels of raw soybeans in the diet. Unsaturated:saturated ratio, saturated, unsaturated, monounsaturated and polyunsaturated fatty acids were similar among treatments. There was no difference in lambs performance in pre or post-weaning periods. Considering that the price of raw soybeans is generally lower than its meal, the inclusion of up to 140 g/kg DM of soybeans is recommended for increasing milk yield, with no detrimental effect on milk efficiency production, milk components and lambs performance. In addition, it is important to highlight that supplementation of up to 210 g/kg DM of raw soybeans made milk fat healthier for human consumption.
Phenylacetylcarbinol (PAC) is a precursor for the synthesis of several pharmaceuticals, including ephedrine, pseudoephedrine, and norephedrine. PAC is commonly produced through biotransformation using microbial pyruvate decarboxylase (PDC) in the form of frozen-thawed whole cells. However, the lack of microorganisms capable of high PDC activity is the main factor in the production of PAC. In addition, researchers are also looking for ways to utilize agro-industrial residues as an inexpensive carbon source through an integrated biorefinery approach in which sugars can be utilized for bioethanol production and frozen-thawed whole cells for PAC synthesis. In the present study, Candida tropicalis, Saccharomyces cerevisiae, and the co-culture of both strains were compared for their biomass and ethanol concentrations, as well as for their volumetric and specific PDC activities when cultivated in a sugarcane bagasse (SCB) hydrolysate medium (SCBHM). The co-culture that resulted in a higher level of PAC (8.65 +/- 0.08 mM) with 26.4 +/- 0.9 g L-1 ethanol production was chosen for further experiments. Biomass production was scaled up to 100 L and the kinetic parameters were studied. The biomass harvested from the bioreactor was utilized as frozen-thawed whole cells for the selection of an initial pyruvate (Pyr)-to-benzaldehyde (Bz) concentration ({[
Fast pyrolysis is a promising method that is being investigated for application in the degradation of lignin into phenolic chemicals. In this study, enzymatic/mild acidolysis lignin (EMAL) isolated from eucalyptus (E-EMAL) and wheat straw (W-EMAL) were characterized by pyrolysis-gas chromatography/mass spectrometry. The results showed that the compositions and yields of the products were determined by the lignin type and pyrolysis temperature. The identified products from the E-EMAL and W-EMAL pyrolysis mainly included G-phenols such as 2-methoxy-4-vinylphenol and guaiacol, S-phenols such as syringol and 2,6-dimmethoxy-4-(2-propenyl)-phenol, and H-phenols such as phenol, 2-methylphenol, and 4-vinylphenol. The overall yield of these phenolics varied with the investigated conditions. The G- and S-phenols were the primary products during the E-EMAL pyrolysis, while more H-phenols were produced during the W-EMAL pyrolysis. A compromise mild pyrolysis temperature of 450 degrees C to 650 degrees C resulted in a high phenolics yield, while a temperature greater than 650 degrees C led to the production of more aromatic hydrocarbons.
The agricultural use of sewage sludge and derivatives is to be carried out according to requirements established by Brazilian federal legislation and by legislation of the State of Sao Paulo, which requires that these organic materials must have at least 30 \% of the total organic carbon degraded when incorporated in agricultural soils. To observe the degradation rates of sewage sludge and of organic compost produced from the same sewage sludge mixed with ground material from tree pruning, we performed two respirometry tests according to the modified method of Cetesb (1999). The waste materials were added to bottles containing 500 g of soil collected from the 0.00-0.20 m layer of a Nitossolo Haplico Alico (Hapludox) soil. In Test I, for sewage sludge (L) and sewage sludge compost (C), application rates were calculated to provide percentages of N requirements for one sugarcane cycle, in Mg ha(-1) (wet basis) of waste: L1 21.2 (100 \%); L2 42.4 (200 \%); C1 69.4 (50 \%); C2 138.9 (100 \%); and C3 277.8 (200 \%). Test II was conducted only with sewage sludge, at the rates of 5, 10, 15, and 20 times higher than those recommended in Test I: L3 120; L4 240; L5 360; and L6 480. The CO2-C released was quantified by measuring electrical conductivity. In Test I, the treatments with sewage sludge had lower degradation rates than treatments with sewage sludge compost, probably due to the presence of recalcitrant substances formed during the humification phase of the composting process. The 30 \% degradation rate was attained only by the application rate that was 20 times higher than the rate recommended for a cycle of sugarcane, and thus these waste products could not be used in clayey agricultural soils. Therefore, it is necessary to review the values established by legislation in the State of Sao Paulo.
Paper and plastic are the main materials used in food packaging. In the context of climate change, the importance of tree conservation and the mitigation of the negative environmental impacts caused by fossil consumption and deforestation is greater than ever before. This article reviews the potential of plant-origin feedstock from the Baltic Sea region for use in non-wood-fibre and bio-origin plastic food packaging production. It also presents a systematised literature review of the environmental impacts and applications of tree-free paper, plant-origin plastics, and natural-fibre-reinforced bio-composites in fully green food packaging. The results reveal that beneficial environmental impacts are achieved if waste or by-products are used as feedstock. While the production volumes of alternative materials in Europe are small (0.25\% of paper is made of materials other than wood, and the share of bio-plastic is 0.9\%), we found a large demand and potential for growth. The biggest volumes of natural fibre feedstock in Baltic Sea region countries are generated from wheat. Wheat straw, which is a by-product, has a production volume of 68.71 million tons and is potentially a significant non-wood-paper food packaging source. Agricultural waste generated from sugar beet, maize, potato, and wheat is an environmentally beneficial by-product that could be used for bio-plastic food packaging production.
To meet the demands for resources, food and energy, especially in fast developing countries in the Global South, new infrastructure investments, technologies and supply chains are required. It is essential to manage a transition that minimises the impacts on global environmental degradation while benefits local socio-economic development. Food-bioenergy integration optimising natural capital resources and considering wider environmental and socio-economic sustainability offers a way forward. This study presents an integrative approach enabling whole systems modelling to address the interlinkage and interaction of resource-food-bioenergy systems and optimise supply chains considering poly-centric decision spaces. Life cycle sustainability assessment, optimisation, agent-based modelling and simulation were coupled to build an integrated systems modelling framework applicable to the resource-food-bioenergy nexus. The model building blocks are described before their applications in three case studies addressing agricultural residues and macro-fungi in the Philippines, sugar cane biorefineries in South Africa, and Nipa palm biofuel in Thailand. Our case studies revealed the great potential of untapped biomass including agricultural waste and non-food biomass grown on marginal lands. Two value chain integration case studies - i.e. straw-fungi-energy in Philippines and sugar-energy in Africa - have been suggested as sustainable solutions to recover waste as value-added products to meet food and energy security. Case studies highlight how an integrative modelling framework can be applied to address multilevel questions, taking into account decision-making at different levels, which contribute to an overall sustainability goal. (C) 2020 Elsevier Ltd. All rights reserved.
The yeast Saccharomyces cerevisiae is the most used microorganism for ethanol production, however, on its wild form it cannot assimilate xylose. The previous ex-vivo isomerization of xylose to xylulose catalyzed by the enzyme xylose isomerase (XI) is an alternative to overcome this limitation. The present work evaluated continuous 2G ethanol production through xylose simultaneous isomerization and fermentation (SIF) using xylose isomerase co-immobilized with yeast. From the initial studies carried out with five different industrial S. cerevisiae strains, Itaiquara(R) baker ` s yeast was selected due to its good performance in terms of ethanol yield (0.34 g/g) and productivity (2.1 g/L/h) having xylose as a carbon source. Continuous xylose SIF in a fixed-bed reactor was run for 7 days with high values of ethanol yield (0.37 g/g) and productivity (1.9 g/L/h). The operation for longer periods could be possible upon implementing strategies for pH and contamination control, showing great progress to achieve a feasible industrial 2G ethanol production process. Graphic abstract {[
Contaminated mining soils might pose risk to the environment due to leaching of heavy metals into ground water, especially under acid conditions. Biochar might be an option for retnediation of contaminated mining soils. The aim of this study was to evaluate the effect of soil acidification and biochar (BC) application on Cd, Pb and Zn mobility and chemical fractionation in two mining soils (A and B). Fifteen leaching columns per soil were packed, applying the following treatments: soil +3\% BC; acidified soil; acidified soil +3\% BC and control soil + CaCO3. The control treatment was constituted by the original polluted soil (soil A or soil B). BC was produced by slow pyrolysis at 700 degrees C from sugarcane straw. Ten leaching events were performed and Cd, Pb, Zn and pH were determined for each leaching. A sequential extraction procedure was performed after leaching was finished. The following fractions were evaluated: mobile, exchangeable, bound to Mn oxide, bound to OM, bound to Fe oxide and residual. In the polluted control soil metal mobility was very low. In acidified soils metal mobility increased drastically and BC application reduced the Cd (57-73\%), Pb (45-55\%) and Zn (46\%) concentrations in the leachate. With the sequential extraction it was observed that Cd was mostly bound to the mobile fraction (15-35\%) and exchangeable fraction (7-38\%), Pb was mainly bound to the Mn oxide fraction (32-70\%) and OM (31-43\%) and Zn was principally bound to the residual fraction (31-68\%). Cadmium presented the highest mobility index (33-53\%) and Pb the lowest (1-3\%), which is related to the fractions they are bound in the soil. Field studies would be necessary to confirm the effectiveness of BC application on heavy metals' retention, prior to large scale application. (C) 2016 Elsevier B.V. All rights reserved.
Lignocellulosic biomass is the most abundant renewable resource on earth and currently most of this biomass is considered a low-value waste. Specifically, lignin is an underrated bioresource that is mostly burned for energy production and few value-added products have been created. Since the agro-food industry produces large amounts of wastes that can be potential sources of high-quality lignin, scientific efforts should be directed to this industry. Thus, this review provides a systematic overview of the trends and evolution of research on agro-food system-derived lignin (from 2010 to 2020), including the extraction of lignin from various agro-food sources and emergent applications of lignin in the agro-food chain. Crops with the highest average production/year (n = 26) were selected as potential lignin sources. The extraction process efficiency (yield) and lignin purity were used as indicators of the raw material potential. Overall, it is notable that research interest on agro-food lignin has increased exponentially over the years, both as source (567\%) and application (128\%). Wheat, sugarcane, and maize are the most studied sources and are the ones that render the highest lignin yields. As for the extraction methods used, alkaline and organosolv methods are the most employed (similar to 50\%). The main reported applications are related to lignin incorporation in polymers (similar to 55\%) and as antioxidant (similar to 24\%). Studies on agro-food system-derived lignin is of most importance since there are numerous possible sources that are yet to be fully valorized and many promising applications that need to be further developed.
In this study, lignocellulose biorefineries annexed to a typical sugar mill were investigated to produce either ethanol (EtOH) or 1,3-butadiene (BD), utilizing bagasse and trash as feedstock. Aspen simulation of the scenarios were developed and evaluated in terms of economic and environmental performance. The minimum selling prices (MSPs) for bio-based BD and EtOH production were 2.9-3.3 and 1.26-1.38-fold higher than market prices, respectively. Based on the sensitivity analysis results, capital investment, Internal Rate of Return and extension of annual operating time had the greatest impact on the MSP. Monte Carlo simulation demonstrated that EtOH and BD productions could be profitable if the average of ten-year historical price increases by 1.05 and 1.9-fold, respectively. The fossil-based route was found inferior to bio-based pathway across all investigated environmental impact categories, due to burdens associated with oil extraction. (C) 2017 Elsevier Ltd. All rights reserved.
Southeast Asia (SEA) has large agricultural crop production and huge amounts of crop residues generated annually are commonly burned in the field to quickly clear land for the next crop planting. This study developed annual emission inventory for crop residue open burning (CROB) covering 17 emission species/groups for 10 SEA countries during 2010-2015, illustrated with relative contributions by country and by crop type. The fractions of crop residue subjected to open burning (OB), a large source of uncertainty in the activity data, compiled from surveys in SEA were significantly higher than those suggested in international databases. Emission factors for rice and maize residue OB were obtained from field experiments conducted in Thailand. The best estimates of the annual emissions averaged over 6 years, of air toxics were: 32 Gg of polycyclic aromatic hydrocarbons, 0.03 Gg organ-chlorinated pesticides, 292 Gg total chlorines, and 94 g I-TEQ dioxins. Emissions of PM2.5, BC and OC, in Tg yr(-1), were respectively 1.8, 0.08 and 0.8. The coefficients of variation of annual emissions during the period were relatively small (2.6-8.6\% depending on species) but still showed an increasing trend that reflected the changes in production of major crops during the period. Regionally, CROB shared 10-43\% of the total biomass open burning emissions but varying with country: by far dominant in Vietnam and Philippines, and much less dominant in Indonesia, Myanmar, and Thailand. Rice straw open burning was the most dominant (19-97\%) in the total CROB emissions of the 8 considered crops. The spatial distributions of annual emissions (0.1 degrees x 0.1 degrees) showed higher emission intensity over the areas cultivated with rice and sugarcane, while higher monthly emissions coincided with major harvesting periods in the dry season. The obtained EI data can be further used for air quality modeling to assess effects of CROB emission and to promote non-OB alternatives in the region.
The poultry industry produces abundant quantities of nutrient-rich litter, much of which is composted before use as a soil amendment. However, a large proportion of nitrogen (N) in poultry litter is lost via volatilisation during composting, with negative environmental and economic consequences. This study examined the effect of incorporating biochar during composting of poultry litter on ammonia (NH3) volatilisation and N retention. Biochars produced at 550 degrees C from greenwaste (GWB) and poultry litter (PLB) feedstocks were co-composted with a mixture of raw poultry litter and sugarcane straw {[
This paper explores the economic viability of producing biofuels from Agave in Mexico and the potential for it to complement the production of tequila or mescal. We focus on Agave varieties currently being used by the tequila industry to produce two beverages, tequila and mescal, and explore the potential for biofuel production from these plants. Without competing directly with beverage production, we discuss the economic costs and benefits of converting Agave by-products to liquid fuel as an additional value-added product and expanding cultivation of Agave on available land. We find that the feedstock cost for biofuel from the Agave pina alone could be more than US\$3 L-1 on average. This is considerably higher than the feedstock costs of corn ethanol and sugarcane ethanol. However, there may be potential to reduce these costs with higher conversion efficiencies or by using sugar present in other parts of the plant. The costs of cellulosic biofuels using the biomass from the entire plant could be lower depending on the conversion efficiency of biomass to fuel and the additional costs of harvesting, collecting and transporting that biomass.
Life cycle assessment has been used to investigate the environmental impacts associated with using p-xylene produced from biomass rather than from the processing of naphtha in the production of polyethylene terephthalate (PET). The cases investigated were for polymer production and distribution facilities in the United States. The types of biomass considered were corn stover, willow, and sugar cane (both juice and bagasse). The best case for minimizing global warming potential and fossil energy use involved producing p-xylene from sugar cane juice, while the sugar cane bagasse was burnt to generate electricity. Compared with conventional processing, a net reduction in global warming potential of 87\% and a 26\% reduction in fossil energy use were obtained. Furthermore, it has been shown that savings can be made by producing ethylene glycol from sugar cane bioethano1.1 This would enable the production of a PET bottle sourced completely from biomass. The production of such a bottle would result in an overall 114\% reduction of global warming potential, i.e. the system, as defined, is effectively sequestering CO2 from the atmosphere, and 39\% reduction in fossil energy use. However, the total use of energy, i.e. fossil and renewable, increases by 81\%. Other environmental impacts were also quantified, e.g. eutrophication, for which the biomass systems are generally at a disadvantage compared with production from petrochemicals. Land use and water use were also considered. The current p-xylene market is discussed, and biomass routes face significant barriers to entry. Finally, the sensitivity of the conclusions to different methods of allocation is assessed.
Lignocellulosic biomass is an attractive feedstock for the production of liquid (eg. biofuel) or gaseous (eg. methane) fuels for the transportation sector. The bioethanol production process still produces a large quantity of production waste following the distillation process. Stillage consists mostly of lignin, hemicellulose, extractives, and yeast and therefore does not have any commercial value. The conversion of bioethanol production waste into gaseous biofuels like biogas or biomethane is a promising solution when it comes to transforming stillage into value-added products, enhancing the value of the biomass, and as a strategy for achieving zero-waste societies. This study aims to investigate the potential of bioethanol production waste for biomethane production. The results are compared with samples from different stages of the bioethanol production process. Milled barley straw (Hordeum vulgare) was used as a feedstock to produce energy in the form of methane, and the flue gas pretreatment method (with and without bubbling) was applied. The results show that the methane production yield of bioethanol production waste, which has been pretreated with flue gas without bubbling is 5\% higher than that of untreated substrate, and can achieve 94\% of the methane production of fermented samples. Bioethanol production waste from substrates, which have been pretreated with flue gas with bubbling have a methane production level that is 29\% higher than that of untreated materials. The results suggest that methane yields are influenced by the bubbling process. It is reasonable to use bioethanol production waste for the production of energy in the form of methane and to increase the energy output from the biomass.
Self-compacting concrete (SCC) is an innovative product, which has fluidity and cohesion to cover the entire length of the piece and fill the spaces between reinforcement. However, currently, its use in construction sites is linked to a high consumption of cement. This generates a series of environmental problems such as depletion of natural resources and increased CO2 emissions. To mitigate these environmental problems, it is necessary to seek supplementary, locally available materials, to provide a sustainable and efficient way forward for the construction industry. In this perspective, this research investigates the effects of the use of metakaolin (MK), sugar cane bagasse ash (SCBA), rice husk ash (RHA) and hydrated-lime (HL) on rheological (slump flow, J-ring and V-funnel), mechanical (compressive strength) and durability (electrical resistivity, accelerated carbonation and mercury intrusion porosimetry) behavior in SCC. Portland Cement was replaced from 0\% to 60\% by mineral admixtures in mixtures with and without 10\% HL. The results indicated that the SCC produced with agricultural ashes presented physical behaviors compatible with the standards and obtained compressive strength equivalent to the reference SCC (REF). Moreover, these concretes presented carbonation depth lower than the normative values and electrical resistivity significantly higher than the SCC-REF, reducing the probability of corrosion of the steel bars and, therefore, validating the use of ash obtained from industrial bio-waste in the production of SCC. The HL also presented itself as a good re-alkalizer of the cement matrix.
Calcium silicate slag from the phosphorus fertilizer industry has the potential to be used as a liming agent or for silicon (Si) fertilization in rice production, but it contains trace elements that may contaminate rice grain and straw. A greenhouse study was performed to evaluate the bioavailability of Si and trace elements from slag (0, 1000, 2000, and 4000 mg kg-1) surface-applied or incorporated to a mineral soil and an organic soil. Slag application increased Si availability and rice grain yield relative to the control. Trace element and radioactivity in soil and rice grain were not significantly affected by slag supplementation. The applied slag showed minimal influence on plant available cadmium (Cd), chromium (Cr), or lead (Pb); however, copper (Cu) and zinc (Zn) in the organic soil increased, whereas Ni in the mineral soil decreased. Results indicate that the evaluated slag may be used as a Si fertilizer or liming amendment for rice with minimal environmental risks.
Thailand's ethanol policy is embedded in the Alternative Energy and Development Plan 2015 (AEDP 2015). The policy goal is to increase ethanol production and consumption in 2036 at 223\% of the baseline in 2015. A large demand for feedstock supplies, mainly molasses and cassava to meet the policy target causes concerns over their sufficiency. However, oversupply of ethanol has been observed occasionally. Since ethanol production and consumption are relevant to a number of policies, incoherence and gaps may contribute to the shortcomings. By applying a combined coherence and gap analysis, it is shown that crop zoning is irrelevant to and ineffective in securing the supply of ethanol. On the other hand, demand saturation is primarily due to the ineffectiveness of the state mechanisms. Key factors contributing to the problem are low prices of crude oil, high prices of feedstocks, managing availability of and accessibility to certain types of blended fuels in favor of the low blended ones, incorrect understanding of consumers towards high blended fuels and the public's recent interest towards electric vehicles. Political factors may also account for the slow-growing demand. The developed method is proved to be useful in determining effectiveness of interrelated policies dealing with ethanol.
Prospecting for sustainable resources will be feasible to generate silica materials extensively used for various commercial applications. Accumulated amorphous silica, called phytolith, is found in the crop residues removed during the harvesting process. Hence, it will be beneficial to understand the potential for various kinds of crop residues used as silica production resource regarding their global generation, yield of generation, and enhancement using silicon fertilizer. Of the many crop residues discussed in this study, sugarcane leaves are the most useful potential silica source. Various synthesis methods are continuously developed with the expectation to achieve tunable silica particle properties with high processing efficiency. The applications for silica particles derived from crop residues vary depending on their unique characteristics related to textural and morphological properties. Silica materials developed from crop residues present several challenges involving silica depletion in croplands, segregation of valuable components from crop residues, and the high utilization of high energy and chemical reagents. Utilizing industrial wastes containing silica can be promoted as Si fertilizer to heal silica depletion in croplands. An integrated approach can be conducted applying low energy with fewer chemical methods to recover energy, lignocellulosic materials, carbonaceous materials, and siliceous material from crop residues, simultaneously. {[
Anaerobic treatment of sulfate-rich wastewaters is challenging due to the inevitable biological sulfate reduction to sulfide, which limits biogas use and can negatively impact the treatment performance due to the toxic character of sulfide. Establishing sulfidogenesis during fermentation has recently been highlighted as a novel application for acidogenic systems. Different strategies were applied to recover the efficiency of a thermophilic (55 degrees C) ethanol-fed anaerobic structured-bed reactor operated under acetogenic/sulfidogenic conditions after stress events: the progressive re-insertion of liquid phase recirculation, {[
The re-use of glycerol from biodiesel industry as an alternative lubricant for making high-performance briquettes is usual. However, the technical performance of this agro-industrial residue is not consistent. This study outlines, accordingly, the real risk of introducing glycerol into the co-briquetting of highly caloric by-products of energy-crops. The production of hybrid briquettes consisted of pressing mixtures of residues of sugarcane and sorghum with the liquid additive at 10, 20, and 30 wt.\% in bench-scale hydraulic piston presser machine. Irrespective of the blend, briquettes containing the supplement at the highest level as part of their composition ended up being much more hygroscopic (20.10\%) and less energetic (3.15 GJ m-3). The explanation for the negative impact of glycerol on the thermomechanical behavior of briquettes would be overconcentration of additive capable of effectively defying compacting biomass. The degree of compaction during co-briquetting has likely gone down quickly with a maximizing level of glycerol. As long as the additive is not able to lubricate the feedstock suitably, improbability of biomass particles to successfully bond together to form themselves into mechanically stable and energetically effective briquettes is large. Besides lower density (273.80 kg m-3) and higher relaxation (22.75\%), briquettes with glycerol at 30 wt.\% generally were aesthetically unpleasing. Practically, these products resisted no longer to handling, transportation, and storage. They lost their shape easily during emptying and shifting them, thus, releasing larger quantities of biomass to the environment. Preliminary evidence of high-viscosity glycerol capable of limiting safe and effective production of high-performance briquettes for heating and power exists.
The contamination of agricultural soils with cadmium (Cd) is one of the serious worldwide concerns for food security. Biochar and organic manures have been known for enhancing plant growth and minimizing toxic trace element stress in plants. However, less is known about the effect of different organic amendments on Cd and uptake of essential nutrients by wheat. Thus, the effects of rice straw biochar (RSB), maize stalk biochar (MSB), farmyard manure (FYM), and pressmud (PRM) at a rate of 1\% w/w were tested for Cd immobilization in soil and mineral nutrient availability to wheat crop grown in Cd-spiked soil (6.0 mg kg(-1)). The amendments were added in Cd-spiked soil before 12 days of seed sowing and wheat plants were harvested after maturity (115 days after sowing). The findings revealed that the use of amendments improved the number of grains per spike, straw and grain yield of wheat relative to control treatment. The treatments minimized the Cd and enhanced the contents of zinc (Zn), nitrogen (N), phosphorus (P), and potassium (K) in the leaves and grain of the wheat plants. Cadmium concentrations decreased by 35, 38, 68, and 63\% in wheat grain, and grain yield increased by 19, 31, 68, and 58\% with the application of FYM, PRM, MSB, and RSB, respectively. Overall, the application of MSB was more efficient in decreasing Cd concentrations in leaf and grains of wheat as compared to other conventional organic amendments.
A major environmental problem on a global scale is the contamination of water by dyes, particularly from industrial effluents. Consequently, wastewater treatment from various industrial wastes is crucial to restoring environmental quality. Dye is an important class of organic pollutants that are considered harmful to both people and aquatic habitats. The textile industry has become more interested in agricultural-based adsorbents, particularly in adsorption. The biosorption of Methylene blue (MB) dye from aqueous solutions by the wheat straw (T. aestivum) biomass was evaluated in this study. The biosorption process parameters were optimized using the response surface methodology (RSM) approach with a face-centred central composite design (FCCCD). Using a 10 mg/L concentration MB dye, 1.5 mg of biomass, an initial pH of 6, and a contact time of 60 min at 25 degrees C, the maximum MB dye removal percentages (96\%) were obtained. Artificial neural network (ANN) modelling techniques are also employed to stimulate and validate the process, and their efficacy and ability to predict the reaction (removal efficiency) were assessed. The existence of functional groups, which are important binding sites involved in the process of MB biosorption, was demonstrated using Fourier Transform Infrared Spectroscopy (FTIR) spectra. Moreover, a scan electron microscope (SEM) revealed that fresh, shiny particles had been absorbed on the surface of the T. aestivum following the biosorption procedure. The bio-removal of MB from wastewater effluents has been demonstrated to be possible using T. aestivum biomass as a biosorbent. It is also a promising biosorbent that is economical, environmentally friendly, biodegradable, and cost-effective.
Flint corn processing method {[
Biochar has attained significant attention as a beneficial soil amendment amongst growers and researchers. However, the impact of particle size of biochar is yet to be investigated. Here in the present study, we studied three particle sizes (<2 mm, 2-5 mm, and >5 mm) of biochar and two rhizobia strains (Rhizobium leguminoserum (RL) and Rhizogold (RG)) for their effect on the uptake and efficiency of nitrogen (N) in lentils. The two years experiment followed a randomized complete block design with split plot arrangement replicated three times. The data revealed that grain N, straw N, N uptake, N recovery efficiency (NRE), and N agronomic efficiency (NAE) were maximum with biochar smallest size (<2 mm). However, the N physiological efficiency, number of branches and plant height decreased with reduced particle size. Furthermore, the smallest particle size showed more number of pod plant(-1). Biofertilizer strain (RL and RG) significantly increased the straw N but not the grain N. Both strains showed increased NRE and NAE, however, the RL demonstrated 7\% more grain N than the RG. Both strains (RL and RG) demonstrated 16\% and 20\% increase in number of branches plant(-1), 62\% and 48\% in plant height and 2\% and 5\% in root length, respectively. The RL strain improved the number of branches plant(-1) at the lowest (<2 mm) and medium size (2-5 mm) particles size but both RL and RG strains demonstrated increased plant height under the maximum particle size. These results indicated that a mere increase in surface area with decreasing biochar particle size may not serve for enhancing biofertilizer strains performance since reducing particle size may immobilize the starter N applied. However, reducing particle size effect on N cycling into soil plant system was favorable.
Previous works have shown that glycerol, which is a residue from biodiesel production,. can be applied to greatly increase the efficiency of power generation processes consuming biomass, such as sugar cane bagasse (SCB). The proposed process departs from a biomass and glycerol slurry, which is pumped into a pressurized gasifier. The produced gas is cleaned to reach particle content and sizes as well alkaline concentration allowed to be injected into commercially available axial gas turbines. The removal of alkaline is achieved through cooling the gas to temperatures below the dew-point of those chemical species. Energy recovered from that cooling and from the gas turbine exit drives two steam cycles. The present theoretical investigation assesses the effects of glycerol concentration in the slurry with wet biomass fed to the process on its overall efficiency. In addition, the gasifier operational pressure is increased to the limit allowed for air compression by axial compressors without intercooling. This work shows that efficiencies can reach levels nearing 46\% and discusses the effect of glycerol fraction in the biomass slurry on the overall power-generation process. The present work is a technical feasibility study. Economic analysis or considerations are beyond its scope and have been left for future investigations.
Biotechnological conversion of biomass into fuels and chemicals requires hydrolysis of the polysaccharide fraction into monomeric sugars. Hydrolysis can be performed enzymatically and with dilute or concentrate mineral acids. The present study used dilute sulfuric acid as a catalyst for hydrolysis of Eucalyptus grandis residue. The purpose of this paper was to optimize the hydrolysis process in a 1.41 pilot-scale reactor and investigate the effects of the acid concentration, temperature and residue/acid solution ratio on the hemicellulose removal and consequently on the production of sugars (xylose, glucose and arabinose) as well as on the formation of by-products (furfural, 5-hydroxymethylfurfural and acetic acid). This study was based on a model composition corresponding to a 2 3 orthogonal factorial design and employed the response surface methodology (RSM) to optimize the hydrolysis conditions, aiming to attain maximum xylose extraction from hemicellulose of residue. The considered optimum conditions were: H2SO4 concentration of 0.65\%, temperature of 157 degrees C and residue/acid solution ratio of 1/8.6 with a reaction time of 20 min. Under these conditions, 79.6\% of the total xylose was removed and the hydrolysate contained 1.65 g/l glucose, 13.65 g/l xylose, 1.55 g/l arabinose, 3.10 g/l acetic acid, 1.23 g/l furfural and 0.20 g/l 5-hydroxymethylfurfural. (c) 2006 Published by Elsevier Ltd.
The removal of heavy metal ions from industrial wastewater by adsorption has been central to the environment for decades, where common adsorbent materials are often limited by poor efficiency, complex fabrication and long processing time. Porous carbon derived from biospecies holds promise to address the limitations. In this study we converted bagasse into a carbon composite having hierarchically porous structure; the composite's dispersion phases - iron oxide and manganese oxide - were synthesized by a simple one-step liquid-phase reaction method. Featuring large specific surface area of 350.8 m(2) g(-1), the composite demonstrated exceptional Hg (II) removal efficiency of 96.8\%, adsorption rate of up to 96.8\% within 150 min and adsorption capacity of 9.8 mg g(-1). In comparison with other removal materials, our work is outstanding in terms of both removal efficiency and synthesis simplicity. The high efficiency is attributed to the synergy between physical adsorption referring to hierarchically porous structure and chemical adsorption relating to functional complexation processes. It provides a new avenue for the development of high-performance adsorbent materials for heavy metal removal from aqueous media.
The long-term greenhouse gas mitigation and economic impacts of integrating bioenergy from cassava residues into a national energy mix, based on South Africa, was assessed using Long-range Energy Alternatives Planning (LEAP) models for three integration schemes {[
The sugar cane production is one of the main economic activities of the agriculture sector in several places around the world. Nowadays, the sugarcane production zones face different technologic, economic, and social problems that impact negatively their profitability. The low price of sugar in the market demands the search of alternatives; being the bioethanol production from resides of the sugar cane industry an attractive option. This way, this paper presents a new approach for using the residues from the sugar cane industry to yield a sustainable biorefinery. In this approach, process integration techniques have been implemented to optimize the overall process. A case study from the State of Michoacan in Mexico is presented, where the proposed approach shows significant economic, environmental, and social benefits.
Purpose Life cycle assessment (LCA) has become a standard for assessing what impacts do products and/or services have throughout their entire life cycle. Since the inception of LCA technique, studies have been conducted in different parts of the world, including Tanzania. This study describes the current status of LCA, capacities, and networking in Tanzania. The study has identified what has already been done and potential research gaps that could be explored in future LCA studies. Methods A state-of-the-art review was conducted on published articles, reports, and other materials on LCA in Tanzania (covering a time frame of 1990-2015) which were searched on databases of scientific research and the general internet using a combination of keywords: ``life cycle assessment and Tanzania{''
Second-generation bioethanol is a promising source of renewable energy. In Brazilian mills, the production of ethanol from sugarcane (first generation, 1G) is a consolidated process performed by Saccharomyces cerevisiae and characterized by high substrate concentrations, high cell density, and cell recycle. The main bacterial contaminants in 1G fermentation tanks are lactic acid bacteria, especially bacteria from the Lactobacillus genus, which is associated with a decrease in ethanol yield and yeast cell viability, among other negative effects. Second-generation (2G) bioethanol production is characterized by the conversion of glucose and xylose into ethanol by genetically modified or non-Saccharomyces yeasts. Spathaspora passalidarum is a promising non-Saccharomyces yeast for 2G ethanol production due to its ability to effectively convert xylose into ethanol. The effect of bacterial contamination on the fermentation of this yeast is unknown; therefore, L. fermentum, a common bacterium found in Brazilian 1G processes, was studied in coculture with S. passalidarum in a fed-batch fermentation process similar to that used in 1G mills. Individually, L. fermentum I2 was able to simultaneously consume glucose and xylose in nutrient-rich broth (Man, Rogosa, and Sharpe (MRS + xylose) but failed to grow in a glucose- and xylose-based synthetic broth. In coculture with S. passalidarum, the bacteria remained at a concentration of 10(8)UFC/mL throughout cell recycling, but no flocculation was observed, and it did not affect the fermentative parameters or the cellular viability of the yeast. Under both conditions, the maximum ethanol production was 21gL(-1) with volumetric productivity ranging from 0.65 to 0.70gL(-1)h(-1). S. passalidarum was thus shown to be resistant to L. fermentum I2 under the conditions studied.
Brazil, which has a great territorial extension, with fertile soils and availability of water and, in this way, can produce a diversity of vegetal products with bioenergetics potential. Thus, this study aims to evaluate the technological characteristics of saccharine substrates of direct fermentation for ethanol production as well as to analyze the fermentative profile of FT-858 yeast in different culture conditions. For this, a bibliographic survey was carried out comparing the technological qualities of the analyzed biomasses. To evaluate the fermentative capacity, the saccharine substrates were used at concentrations of 18 and 32 degrees Brix at 30 degrees C for 24 hours in test tubes containing Durhan tubes. For the analysis of the fermentation profile the yeasts were grown in 2\% YPD medium and the biomass obtained was used in the saccharine substrates of direct fermentation for 50 hours. The saccharine substrates presented potential for ethanol production: sugar cane and saccharine sorghum. The yeast FT-858 presented fermentation capacity in the different substrates in the concentrations of Brix analyzed, presenting a better fermentative performance in sugarcane broth and the highest concentrations of ethanol occurring in the times of 10 and 15 hours of fermentation for both substrates.
Rising fuel prices and environmental issues have paved the way for the exploration of cellulosic ethanol. However, challenges involving substrate hydrolysis and cost-effectiveness still limit the efficient bioconversion and utilization of cellulosic ethanol. We aimed to evaluate a cheaper and abundantly available wild sugarcane variety, Saccharum spontaneum, as the raw substrate for bioconversion of ethanol by Pichia stipitis NCIM3498. Three different strategies for substrate hydrolysis using acid (dilute sulfuric acid) and alkali (dilute sodium hydroxide) and aqueous ammonia (AA) treatment followed by enzymatic hydrolysis were studied. A maximum of 631.5 +/- 3.25 mg/g sugars with 89.38\% hydrolytic efficiency (HE) could be achieved after enzymatic hydrolysis of AA-pretreated S. spontaneum. All the substrate hydrolysates were evaluated for ethanol conversion in batches by P. stipitis. The microbial fermentation of released sugars into ethanol showed (g/g) 0.36 +/- 0.011, 0.384 +/- 0.022, 0.391 +/- 0.02, and 0.40 +/- 0.01 yield from detoxified acid hydrolysate and acid-, NaOH- and AA-pretreated substrate S. spontaneum enzymatic hydrolysates, respectively. (C) 2010 Elsevier Ltd. All rights reserved.
Due to rapid growth in population and industrialization, worldwide ethanol demand is increasing continuously. Conventional crops such as corn and sugarcane are unable to meet the global demand of bioethanol production due to their primary value of food and feed. Therefore, lignocellulosic substances such as agricultural wastes are attractive feedstocks for bioethanol production. Agricultural wastes are cost effective, renewable and abundant. Bioethanol from agricultural waste could be a promising technology though the process has several challenges and limitations such as biomass transport and handling, and efficient pretreatment methods for total delignification of lignocellulosics. Proper pretreatment methods can increase concentrations of fermentable sugars after enzymatic saccharification, thereby improving the efficiency of the whole process. Conversion of glucose as well as xylose to ethanol needs some new fermentation technologies, to make the whole process cost effective. In this review, available technologies for bioethanol production from agricultural wastes are discussed. (C) 2011 Elsevier Ltd. All rights reserved.
Fossil fuels such as oil, gas, and coal have driven the world's economies since the industrial revolution and have released carbon emissions in the process. About 26 billion tons of carbon dioxide are produced every year and this is still increasing. The 1997 Kyoto agreement is the world's only attempt to regulate carbon emissions. Diesel engines have been widely used as the major propulsion power sources because of their simple, robust construction coupled with high thermal efficiency and specific power output with high fuel economy. However, diesel engines are the major contributors of various types of air pollutants such as carbon monoxide (CO), oxides of nitrogen (NOx), particulate matter (PM), and other harmful compounds. The reduction in engine emissions is a major research objective in the engine development because of increasing concern for the environment pollution and more stringent government regulation on exhaust emissions. It is difficult to reduce PM and NOx simultaneously owing to the trade-off between PM and NOx {[
Preparation of leather like material, i.e., regenerated leather (RGL) from finished leather wastes is economical and helps in reducing environmental pollution. Incorporating plant fibers (PFs) into RGL enhances its mechanical properties. Plant fibers are exploited as reinforcement materials owing to their low cost, fairly good mechanical properties, high specific strength, non-abrasive, eco-friendly and bio-degradability characteristics. Fiberized leather wastes and PFs were mixed in various proportions to prepare regenerated leather composites (RLCs). Plant fibers viz., coconut, sugarcane, banana and corn silk were used for the study. RGL and RLCs were characterized physicochemically using Fourier transform infrared spectroscopy, thermo gravimetric analysis and scanning electron microscopy. Results clearly portrayed that PFs significantly improved the mechanical and thermal properties of RLCs. Among the composites, RLC prepared using leather waste and coconut fiber (50:40 ratio) proved to be a better composite with potent properties. RLCs are promising for the preparation of leather goods and footwear materials in addition to its cost-effectiveness and environmental pollution abatement.
Composting degradable organic matters with chemical fertilizers produces stable material with the aid of organisms and makes nutrients readily available to plants. A field study was carried out for incorporation of the urea and KOH treatments on composting fresh cattle manure, wheat straw, sawdust, and dried leaves to evaluate the decomposition rate during four months. The mineralization of the organic wastes as increased in microbial biomass carbon (MBC) and organic matter (OM) loss was higher in urea treatments, in contrast with KOH treatments which need more time for optimum decomposition. Lac case activity reduced in the manure but increased in other organic wastes and in the urea treatments. Water-soluble carbon (WSC) decreased in all organic wastes, particularly in urea-treated manure. The fluctuation of pH and electrical conductivity (EC) were observed for four months but increased at the end of the experiment. Total organic carbon (TOC) reduced, and total nitrogen (TN) has risen, especially in the presence of urea treatments; so, the C/N ratio significantly decreased and the trend of composting progressed overtime. Insufficient technical planning in composting has led to changed approaches to increase elements availability with the management of existing plantations. The successive applications of urea were observed to enhance the rate of organic wastes decomposition than KOH treatments. This study further recommends application of urea and KOH with degradable organic materials in which this method should be improved with the ability to mineralize nutrients rapidly, which could make them advantageous to crop growth.
This research aims to study the wet torrefaction (WT) and saccharification of sorghum distillery residue (SDR) towards hydrochar and bioethanol production. The experiments are designed by Box-Behnken design from response surface methodology where the operating conditions include sulfuric acid concentration (0, 0.01, and 0.02 M), amyloglucosidase concentration (36, 51, and 66 IU), and saccharification time (120, 180, and 240 min). Compared to conventional dry torrefaction, the hydrochar yield is between 13.24 and 14.73\%, which is much lower than dry torrefaction biochar (yield >50\%). The calorific value of the raw SDR is 17.15 MJ/kg, which is significantly enhanced to 22.36-23.37 MJ/kg after WT. When the sulfuric acid concentration increases from 0 to 0.02 M, the glucose concentration in the product increases from 5.59 g/L to 13.05 g/L. The prediction of analysis of variance suggests that the best combination to maximum glucose production is 0.02 M H2SO4, 66 IU enzyme concentration, and 120 min saccharification time, and the glucose concentration is 30.85 g/L. The maximum bioethanol concentration of 19.21 g/L is obtained, which is higher than those from wheat straw (18.1 g/L) and sweet sorghum residue (16.2 g/L). A large amount of SDR is generated in the kaoliang liquor production process, which may cause environmental problems if it is not appropriately treated. This study fulfills SDR valorization for hydrochar and bioenergy to lower environmental pollution and even achieve a circular economy. (C) 2021 Elsevier Ltd. All rights reserved.
Concurrent sampling of PM2.5 aerosol at a roadside of heavy traffic (1.2 m above ground) and on a nearby rooftop (50 m above ground) was conducted at a same location in urban Guangzhou in September. October 2006 and January 2007. The samples were analyzed for eighteen polycyclic aromatic hydrocarbons (PAHs), together with major aerosol constituents and certain organic tracers for vehicular emissions (hopanes) and biomass burning (levoglucosan). Elemental carbon (EC) and hopanes were observed to be lower by 21-38\% and 28-84\%, respectively, at the rooftop than the roadside, confirming vehicular emissions as a significant local PM source. On the other hand, sulfate showed little vertical gradient, consistent with its secondary origin and its regional characteristics. The roadside-rooftop sample pairs have provided an opportunity in evaluating relative contributions of vehicular emissions and regional sources to ambient PAHs in this urban location. Concentrations of the total PAHs were similar to 43\% lower at rooftop in the September 2006 samples while they were at similar levels between rooftop and roadside in the October 2006 and January 2007 samples. Sources of PAHs were investigated through comparing ambient data of PAH isomer pairs and PAH/EC ratios with relevant source profiles including those of Guangzhou roadway tunnel emissions, rice straw/sugarcane leave combustion, and industrial coal combustion. The 4-ring PAHs such as pyrene and fluoranthene had a shift in their dominating source from vehicular emissions in September and October to regional combustion source in January. A few major 5- and 6-ring PAHs such as benzo{[
In this study, sequential leaching (60 degrees C, 5 min) and wet torrefaction (200 degrees C, 5 min) of biomass were carried out to improve the fuel properties of waste biomass, made up of empty fruit bunches (EFB), rice straws (RS), or sugarcane bagasses (SB). Most of the hemicellulose was removed during wet torrefaction. The ash removal efficiency by sequential leaching and wet torrefaction differed depending on the biomass. After leaching and wet torrefaction, the ash removal efficiency of the EFB was the highest (67.99\%). Most of the potassium and chloride in the biomass were removed. In particular, the removal efficiencies for the EFB were the highest (98.62\% and 99.27\%, respectively). The heating values increased by 4.42\% in the EFB, 4.68\% in the RS, and 5.30\% in the SB. Pellet production was successfully carried out with the leaching and wet-torrefied biomass (EFB). The hydrophobicity of the pellets was considerably higher than that of the raw material.
We hypothesized that the inclusion of calcium salts of fatty acid (CSFA) into the diets and the fatty acid (FA) profile of the supplements would impact performance and meat characteristics of Bos indicus bulls. Hence, the objective was to evaluate the effects of CSFA profiles on intake, body weight (BW), carcass, and meat characteristics of feedlot-finished B indicus bulls. Fifty-three Nellore bulls {[
An acid catalyzed steam explosion pretreatment system was developed to process wood chips for biomass conversion. The degree of mixing in the pressurizing process was found to be a crucial factor to saccharification efficiency. With a low load fill (100 l, half load) in the pressurized vessel, ribbon blender provided enough mixing power for wood chips. The temperature difference in the reactor was found to be less than 15 degrees C, the total saccharification efficiency can be up to 63\%. At high load fill condition (2001, full load), the temperature difference under regular mixing was found to be quite large (20 degrees C) with a low saccharification efficiency of 38\%. To increase the temperature uniformity, an intermittent pressure pulsation method was used. The pressure pulses helped the vertical mixing and a total saccharification efficiency up to 65\% can be reached in the improved pretreatment process. (C) 2016 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
A preliminary theoretical feasibility study on the application of new concepts for thermoelectric power generation consuming biomass mixed with glycerol has been completed. Two main alternatives (A and B) have been envisage. At Configuration A, wet sugar-cane bagasse (SCB) is dried at atmospheric pressure. From that, the biomass is mixed with raw glycerol to obtain a high dry-solid content slurry, which is pumped into the gasifier. This greatly simplifies the feeding of particulate solids into pressurized vessels, which otherwise would require costly and cumbersome series of lock hoppers operating sequentially. The produced gas is cleaned to bring the particle content and size as well alkaline concentration within the acceptable limits for injections into standard gas turbines. At Configuration B, the wet SCB is mixed directly with raw glycerol and pumped into the gasifier, therefore dispensing the drying phase. Optimizations of the gasifier characteristics and air injection rates have been conducted having the exergetic efficiency as objective function. In both cases, the complete power generation concepts are optimized aiming the maximization of respective 1st Law efficiencies. (C) 2016 Elsevier Ltd. All rights reserved.
This paper discussed the possibility of replacing the internal combustion engine of the series plug-in hybrid electric vehicle (PHEV) powered by gasoline A and Brazilian gasoline in single-fuel mode by one fuelled with 50\% bioethanol and 50\% biogas in dual-fuel mode. The simulation of the combustion of the fuels selected, such as bioethanol, biogas and gasoline A, was carried out through GASEQ software to calculate the energy-ecological efficiency of the single-fuel and dual-fuel modes. The well-to-pump (WTP) emissions of the bioethanol and biogas production from sugarcane were evaluated through GREET software. The tank-to-wheel (TTW) emissions were determined to each series PHEV operating modes. Thus, the well-to-wheel (WTW) emissions were calculated through the sum of the WTP, TTW and electricity mix emissions. According to the results, the energy-ecological efficiency for the dual-fuel mode was 10.7\% and 24.1\% higher than that found for the single-fuel mode powered by gasoline and Brazilian gasoline, respectively. The analysis showed that the losses during the biogas production aggravate linearly the WTP emissions, and consequently, the WTW emissions of the series PHEV. Besides that, the dual-fuel mode presented 15.5\% and 12.8 less TTW emissions than the single-fuel mode powered by gasoline A and Brazilian gasoline, respectively. Compared to the emission standards, the dual-fuel mode presented TTW emissions 30.5\% higher than the European Union emission standard by 2021. Although the dual-fuel mode does not meet any of the emission standards, this engine mode can be an alternative to at least reduce the tailpipe emissions.
This document studies the hydration dynamics of five lignocellulosic biomasses (sorghum and wheat straws, corn stover, agave and sugarcane bagasses) commonly used as feedstock in biorefining processes. Water holding and water retention capacities are measured for different particle sizes of each lignocellulosic biomass at different hydration times under isothermal conditions. Water holding capacity exhibits a first-order dynamic behaviour fitting a Langmuir isotherm as a function of hydration time. The two isotherm constants are interpreted as the maximum water holding value of the lignocellulosic biomass (alpha) and the time typically required to reach it (beta), fitting experimental data with high correlation factors (0.981-0.998). Equilibrium hydration values differ greatly for each biomass and particle size, demonstrating that holding and retention capacities are associated to biomass type and surface size. The relationship between hydration with pH decay and glucose release due to microbial and fungal activity during hydration dynamics was also evaluated.
The agroindustry by-products viz., peanut shell, corn cob, sawdust, paddy husk, pressmud, rice and wheat straw, coconut husk, etc. are generated in huge amount. These are either incinerated or disposed of directly to the landfills. The management of agroindustry by-products can be done by solid state fermentation by conversion into value-added products viz., soil conditioner, compost, single cell protein, mushroom, enzymes, organic acids, biogas, wax, feed for livestock, plant growth substances etc. The review here focuses on management of sugar industry by-product i.e., pressmud by conversion into various value-added products viz., wax, biogas, compost, plant growth, carbon sequestration, feed for livestock, carrier for plant growth promoting rhizobacteria, single cell protein and enzymes. There are very few reports on the management of pressmud by conversion to value-added products. Hence, pressmud agroindustry by-product for value-added products was focused in this review. The agroindustry by-product pressmud is eco-friendly, cheap and also easily available. The review is significant as it mentions the management and value-addition of pressmud, an agroindustry by-product. This will be environmental safe and also economical.
The present study aimed to characterize and evaluate the hydrolysis of sisal fibers for ethanol production. Acid hydrolysis of the fiber was performed and main products determined were xylose and glucose. However, xylose and arabinose (pentoses) are not fermented by the conventional yeast Saccharomyces cerevisiae. Prehydrolysis at 105 degrees C was efficient, removing most of the pentoses. The main product formed in acid hydrolysis at 160 degrees C was glucose, which can be metabolized by the yeast S. cerevisiae through alcoholic fermentation. In these conditions ethanol was produced with 92\% conversion of initial total reducing sugars (0.47 g/g of ethanol yield). Sisal has potential as a raw material for ethanol production since it is not a food source, has high cellulose content and low biomass cost. (c) 2012 Elsevier Ltd. All rights reserved.
In this study, a novel class of polyesters of glycerol, aconitic acid, and cinnamic acid were synthesized along with their hydroxyapatite (HA) composites, and studied for their potential application in bone defect repair. An osteogenic study was conducted with human adipose derived mesenchymal stem cells (hASCs) to determine the osteoinductive ability of aconitic acid-glycerol (AG) polyesters, AG:HA (80:20), aconitic acid-glycerol-cinnamic acid (AGC) polyesters, and AGC:HA (80:20) to serve as bone scaffolds. The results indicate that AGC scaffolds have the highest mechanical strength in comparison to AG, AG:HA (80:20), and AGC:HA (80:20) scaffolds due to its low porosity. It was determined by cytotoxicity and osteogenesis experiments that hASCs cultured for 21 days on AG:HA (80:20) scaffolds in stromal medium exhibited a greater number of live cells than control PCL:HA composites. Moreover, hASCs cultured on foamed AG:HA (80:20) scaffolds resulted in the highest levels of mineralization, increased alkaline phosphatase (ALP) expression, and the greatest osteocalcin (OCN) expression after 21 days. Overall, AG:HA (100:0 and 80:20) scaffolds had higher mechanical strength and cytocompatibility than the PCL:HA control. Invitro osteogenic study demonstrated that AG:HA (100:0 and 80:20) synthesized using sugarcane industry by-products hold potential as scaffolds for bone tissue engineering applications.
Cement manufacture accounts for 5\% of worldwide carbon dioxide emissions, resulting in significant environmental issues, and using supplemental cementitious materials (SCM) is an efficient strategy to minimise cement consumption. Self-compacting concrete (SCC) often relies on high amounts of binder and chemical additives to maintain workability. Thus, reducing the embodied carbon of SCC materials becomes essential for its wider application. Powdered bio-composites (PBCs), such as rice husk ash (RHA), bagasse ash (BA), palm oil fuel ash (POFA), groundnut shell ash (GSA), and eggshell ash (ESA), can be utilised as SCM for SCC. This paper systematically reviewed the physical properties, chemical properties, and heat treatment methods of five types of PBCs and their impacts after replacing cement in SCC. The review disclosed that heat treatment could effectively reduce the value of loss on ignition (LOI), thus ensuring the activity of PBCs. High-temperature, short-duration incineration or low-temperature incineration for a long time can be effective. The review revealed that adding the five types of PBCs will reduce the workability of SCC, and RHA has the greatest negative impact. Segregation occurs when the cement replacement rate with RHA exceeds 20\%. All five types of PBCs improve the mechanical properties of SCC to a certain extent after replacement. The preferred replacement rates are 5\%-20\% for RHA, BA and GSA, while for POFA the preferred rate could exceed 30\%. The preferred rate is not conclusive for Eggshell ash, as it may lead to either positive or slightly negative impacts regarding compressive strength. In addition, adding an appropriate amount of PBCs will increase the durability of hardened SCC. The summarised impacts were also correlated with the microstructure of SCC through various analysis tools. The paper reveals the current gaps in applying PBCs in SCC and proposes strategies to design environmentally friendly SCC containing PBCs.
trans-Aconitic acid (TAA) is an unsaturated tricarboxylic acid often found in natural sources like cane molasses, beet roots, and so forth. Because of potential applications as plasticizers, biodegradable polyesters for tissue engineering, acidulants in food processing, wetting agents in surfactants, and as drugs in neuromedical therapies, its production has got researchers' attention. Fermentation is the promising and green route for the continuous production of TAA that could meet industrial demands. However, separation of biotechnologically produced TAA from fermentation media is a challenging task. In this work, the effect of diluents on liquid-liquid extraction of TAA was investigated using six diluents of varied chemical nature, alcohols (lauryl alcohol and benzyl alcohol), ketones (cyclohexarione and MIBK), and inactive hydrocarbons (benzene \& heptanes) with tri-n-butyl phosphate (TBP). The reactive extraction equilibrium was analyzed using parameters such as distribution coefficient (K-D), loading ratio (Z > 1), and extraction efficiency (E).The obtained K-D values lies in the range of 0.001-9.483, whereas maximum extraction achieved was 90.46\% in MIBK with TBP 50\% (v/v). In addition, it was also observed that physiochemical parameters of diluents like dielectric constant (K), dipole moment (mu), and Dimroth-Reichardt empirical parameter (E-T) have a significant effect on extraction efficiency.
Composites of high-density biopolyethylene (HDBPE) obtained from ethylene derived from sugarcane ethanol and curaua fibers were formed by first mixing in an internal mixer followed by thermopressing. Additionally, hydroxyl-terminated polybutadiene (LHPB), which is usually used as an impact modifier, was mainly used in this study as a compatibilizer agent. The fibers, HDBPE and LHPB were also compounded using an inter-meshing twin-screw extruder and, subsequently, injection molded. The presence of the curaua fibers enhanced some of the properties of the HDBPE, such as its flexural strength and storage modulus. SEM images showed that the addition of LHPB improved the adhesion of the fiber/matrix at the interface, which increased the impact strength of the composite. The higher shear experienced during processing probably led to a more homogeneous distribution of fibers, making the composite that was prepared through extruder/injection molding more resistant to impact than the composite processed by the internal mixer/thermopressing. (c) 2012 Elsevier Ltd. All rights reserved.
A study was undertaken to assess the effects of levels and timings of incorporation of leucaena {[
This work aims to investigate the thermal decomposition and reaction kinetics of the hybrid energy cane, as well as its thermochemical properties. Lower and higher heating values (15.42 and 17.01 MJ kg(-1), respectively) as well as the cellulose content (45.61\%, extractive-free basis) were similar to native energy canes and sugarcane residues. The thermogravimetric analysis was conducted using four heating rates (5-20 K min(-1)) in a nitrogen atmosphere. Three thermal decomposition stages were distinguished: dehydration, pyrolysis, and carbonization. Two mathematical approaches (single-step and multistep reaction models) were evaluated for pyrolysis. Considering the first case, activation energies (92.5-234.4 kJ mol(-1)) were calculated applying isoconversional methods (Friedman, Flynn-Wall-Ozawa, modified Coats-Redfern, and Vyazovkin), conversion function which represents the reaction model (sixth-order reaction) by the master plots method, and pre-exponential factor logarithm (11.40 s(-1)) by the linearization method considering the global activation energy (135.8 kJ mol(-1)). For the second case, average activation energies (63.0-174.0 kJ mol(-1)), pre-exponential factors logarithm (1.82-12.24 s(-1)), reaction orders (1-1.5), and compositions (0.20-0.32) were obtained in all heating rates for extractives, hemicellulose, cellulose, and lignin, applying independent parallel reactions scheme (IPRS). Simulating conversions and conversion rates for both approaches, the IPRS showed better agreement with experimental data (average deviation < 5\%).
An increase in world energy consumption and its subsequent effect of carbon emission necessitates a shift towards the use of clean and sustainable fuels. Biomass is a promising resource for energy generation owing to its renewable nature and substantial energy content. The addition of plastics to improve the product yield has also been elaborated. Thermogravimetric analysis is a technical tool that can be used to elucidate the pyrolysis temperature and heating rate. Activation energy helps to identify the energy requirement for the pyrolysis process. Kinetics of the pyrolysis process is an effective tool for determining the minimum energy requirement and feasibility. This review highlights the importance of reaction kinetics, exergy, and energy analysis. The liquid fuel obtained through the thermal cracking of biomass has the potential to be used as a blend with conventional petroleum fuels. Substitution/blending of pyro-oil with petroleum fuels helps to reduce greenhouse emissions and global warming. The oxygen content of rice straw and Alga Sargassum sp. is 55 and 67\%, respectively. Energy and exergy analysis improves the process economy. The success of any technology depends on its easy handling and economic feasibility. This review is the first of a kind in throwing light on the energy and exergy analysis of the pyrolysis process. Pyro-oil has an increased amount of oxygen content which has to be upgraded for further use. Pyrolysis also serves as an efficient tool for converting plastic waste into energy.
The physical and chemical properties of stalk fiber extracted by different method was important for the characters of the product. And the research laid the foundation for the complex utilization of eggplant stalk.Morphology of eggplant stalk fiber was determined by Feica microscope, the length, width and length to wide ratio were analyzed by SPSS 17.0. Chemical compositions different analysisof eggplant stalk fiber extracted by mechanical process were analyzed by applying Block test method with Design-expert 6.0.10.The result present that length, width, and length to wide ratio of stalk fiber were 11 mm, 1338 um,20,respectively. Cellulose content of eggplant stalk was 34.31 \%, hemi-cellulose content was 11.03\%, lignin content was10.69 \%.Cellulose content of eggplant stalk fiber was 36.2 \%, hemi-cellulose content was18.55 \%,lignin content was 17.49\%.Hemi-cellulose increased by 7.52 \%, cellulose increased by1.89 \%, lignin increased by 6.8 \%.The composition of fiber had significant difference.Beating degree was positively correlated with the beating time, beating time and wet weight were a negative correlation. Strength of stalk fiber was positively with the gramme, and strength was8.3N when gramme was 60 g/m(2).
In oil-well cementing, Portland cement is commonly used as a binder in cement slurry formulations. However, a significant amount of CO2 is released into the atmosphere during the production of clinker, the main in-process materials in cement manufacturing. Again, the use of non-renewable resources in cement production makes the process unsustainable. Over the years, chemical and physical analyses of some industrial and agro wastes have revealed characteristics that make them useful as supplementary cementitious materials. Some of these byproducts contain chemicals that can be extracted to modify the fresh and hardened properties of cement-based materials. These materials include coal fly ash, ground granulated blast furnace slag (GGBFS), silica fume, granite waste powder (GWP), rice biomass, palm oil biomass, sugarcane biomass, wood biomass, coconut biomass, and corn biomass. The purpose of this study is to investigate the industrial and agro wastes that were used in cement-based materials and make recommendations for future applications of these materials in oil-well cementing. An overview of experimental procedures and conclusions from laboratory and field studies conducted to evaluate the performance of such materials as cement admixtures is presented. A summary of key findings has also been reported. We recommend extensive evaluation of GWP as a filler/pozzolanic material or alternative to silica flour as an anti-strength retrogression agent. Secondly, we recommend an investigation into the use of other waste materials such as RHA as fillers in cement formulations to enhance the early-age strength development of fly ash and GGBFS oil-well cement systems, especially at low-temperature conditions. Finally, we recommend an assessment of POFA as an extender and the evaluation of both POFA and RHA as anti-strength retrogression agents in oil-well cement formulations.
The work contributes to the study of the fuel-slurry integrated gasifier/gas turbine (FSIG/GT) concept for the electric power generation process consuming biomass or, more specifically, Sugar cane bagasse (SCB). The FSIG/GT process, allows for pumping of the solid fuel as a slurry into pressurized reactors, therefore dispensing the need for complex systems Of sequential lock hoppers. The slurry drying is achieved through the application of a residual hot gas stream from the process. Because the dryer and gasifier operate at similar pressures, the transfer of particles can be made using simple rotary valves and Archimedes screws. The produced fuel as is cleaned and injected into the turbine. Previous studies were limited at operational pressures around 2 MPa, while the present evaluates the process working at the vicinity of 10 MPa. This requires intercooling between compression stages as a result of limits of the temperature :imposed by the axial compressor blade materials. Rankine cycles are employed to recover energy from the gas-cleaning and exiting process streams as well from the compression intercooling systems. At the present stage investigation, operations at 10 MPa led to overall efficiencies around 34\%. That is significantly higher than that presently practiced at power plants of large sugar and alcohol mills but below that achieved in previous studies of FSIG/GT processes consuming SCB and operating around 2 MPa. The main reason for that is attributed to the impossibility of total energy recover and irreversibilities introduced during intercooling. Future works might improve that value.
Anthocyanins are plant-based pigments known for their wide range of industrial applications. Berries, grapes, purple yam, purple corn, and black rice are among the chief dietary sources of anthocyanins. However, these sources have a well-established market in the food sector and cannot be diverted completely for the extraction of anthocyanins. Hence, there is a need to identify alternative sources of these natural colorants. In this review, color-bearing bioenergy crops with high productivity such as miscanthus, sorghum, and sugarcane have been proposed as potential feedstocks for the recovery of anthocyanins as co-products. The role of genetic modification in the biosynthesis of anthocyanins in these crops has been discussed. A consolidated bioprocessing approach has been proposed for the recovery of anthocyanins from bioenergy crops along with the production of bioethanol and lignin-based chemicals. Such an integrated process could make the overall process for the production of biofuels cost-effective.(c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
In the present study, an attempt was made to investigate the potential of some of the major world's crops, including wheat, corn, rice, barley, sugarcane, sugar beet, potatoes, and oats, to produce biohydrogen. The collectable amount of agricultural residues that could especially be used to produce hydrogen was estimated in Africa, Asia, Central America, Europe, Northern America, Oceania, and South America, and the potential amount of ammonia as the main nitrogen fertilizer was estimated. Double exponential smoothing method was employed to forecast the future crop production and area harvested. It was calculated that about 10.56 (in 2013) and 15.5 (in 2030) Mt of biohydrogen and 59.84 (in 2013) and 85.86 (in 2030) Mt of ammonia could be obtained globally. In addition, the application of biohydrogen from cereal residues to provide their nitrogen requirement was calculated based on the cultivable area. Nitrogen requirements of near 17\%, 31\%, 12\%, and 33\% of the global cultivation area of wheat, corn, barley, and rice would be possibly supplied by the collected residues of the same crops, respectively. Eventually, a discussion has been made on the amount of potentially savable natural gas and reduction in greenhouse gas (GHG) emissions and consequent social costs by global development of biohydrogen industries. Graphical abstract Global Potential of Biohydrogen production from Crops Residues
Since ethanol is considered an essential additive for biofuel production, there may be the opportunity to employ it as such in Mexico. However, an analysis of the ethanol supply chain should be performed first. Therefore, in order to analyze the main variables of the ethanol supply chain, as well as the feasibility for its use, the present research developed a System Dynamics model based on an idea suggested by SENER (Secretariat of Energy in Mexico). The model explores five possible scenarios (between 2014 and 2030), and evaluates the availability of area for the sowing of sugarcane and grain sorghum crops, the production capacity for ethanol and fuel, as well as the possible reduction of carbon dioxide emissions. The model considers the trends and parameters of the agricultural and energy industries, and produces valuable information about future conditions of the Mexican biofuel and fossil fuel production and supply. The obtained results predicted two situations. First, Mexico would face a fuel shortage in the future. Second, from the amount of fuel available by that time, the biofuel produced and accumulated would collaborate little to meet the domestic fuel demand. Also, as System Dynamics is concerned, it is demonstrated that it is a powerful methodology to simulate and understand the biofuel supply chains in emerging markets as Mexico. (C) 2014 Elsevier Ltd. All rights reserved.
Bioethanol production from renewable sources to be used in transportation is now an increasing demand worldwide due to continuous depletion of fossil fuels, economic and political crises, and growing concern on environmental safety. Mainly, three types of raw materials, that is, sugar juice, starchy crops, and lignocellulosic materials, are being used for this purpose. This paper will investigate ethanol production from free sugar containing juices obtained from some energy crops such as sugarcane, sugar beet, and sweet sorghum that are the most attractive choice because of their cost-effectiveness and feasibility to use. Three types of fermentation process (batch, fed-batch, and continuous) are employed in ethanol production from these sugar juices. The most common microorganism used in fermentation from its history is the yeast, especially, Saccharomyces cerevisiae, though the bacterial species Zymomonas mobilis is also potentially used nowadays for this purpose. A number of factors related to the fermentation greatly influences the process and their optimization is the key point for efficient ethanol production from these feedstocks.
In this article, samples of moso bamboo were pretreated with oxalic acid under various process conditions. Response surface methodology was applied to optimize the pretreatment conditions. A three-variable quadratic polynomial regression model was obtained to predict the cellulose content, lignin removal and hemicellulose solubilization. The reliability of the model was also evaluated by the key elements obtained from analysis of variance of the coefficients. The surface response plot and contour plot of the effects were studied to further examine the interactions of the three factors and determine the optimum levels of each factor. Finally, the optimized conditions for oxalic acid pretreatment were temperature 178.4 A degrees C, 3.68 \% oxalic acid and 28.4 min, respectively. The maximum predicted value of cellulose content in the residue fraction was 64.98 \%, along with 79.43 \% lignin removal and 96.71 \% hemicellulose solubilization after the oxalic acid pretreatment.
The work presents additional improvements on the strategy of the Fuel-Slurry Integrated Gasifier/Gas Turbine (FSIG/GT) concept for electric power generation applied to the case of Sugar Cane Bagasse (SCB). The process allows feeding solid fuel particles into pressurized reactors without the need for complex systems of sequential lock-hoppers. For that, the particulate fuel is mixed with water to produce a high dry solid content slurry that is pumped into a pressurized dryer. Since both the bubbling fluidized bed dryer and gasifier operate at similar pressures, the transference of dried particles to the gasifier can be accomplished with simple Archimedes screws. As the particles are dried before gasification, the process also circumvents the difficulties of fuel slurry ignition, which usually require pure oxygen combined with hydrocarbons. The gas stream leaving the gasifier is cleaned and injected into a gas turbine combustor or combustors. Heat recovering is accomplished by Rankine cycles. The present phase follows preliminary studies where the rates of air and steam injections were variables on the optimization of the dryer and gasifier. Now, the studies include the dryer and gasifier diameters as additional variables for optimizations. The work considers exergetic and cold efficiencies as objective functions. The investigation demonstrates the possibility of achieving higher overall power generation efficiency, which surpasses that achieved by other strategies such as high-pressure Rankine, Biomass Integrated Gasification/Gas Turbines, and combined cycles using pressurized-chamber boilers. The present work concentrates on a possible configuration for the FSIG/GT process that does not require steam for fuel gasification; thus just compressed air is injected into that equipment. Future works will explore other alternatives.
In this work, the synthesis of biochar from several biomass wastes to act as matrix for urea was investigated. The objective was to select the most promising biochar synthesis condition that result in a matrix with the highest urea retention and subsequent slow release as well as to understand the urea-biochar interaction. A quite simple urea impregnation method was proposed and investigated for biuret formation; its experimental conditions were optimized to increase final urea retention performance. The results pointed out that the urea-biochar interaction has chemical nature, in which the lower presence of mineral elements associated with an acid surface seemed to favor the urea retention. The material impregnated at 133 degrees C for 1 h with the straw biochar synthesized at 400 degrees C for 0.5 h showed the lowest initial release of urea (approximate to 17 wt. \%). However, it presented a high content of biuret (approximate to 8 wt. \%). Thus, an alternative material was produced applying a shorter period of urea impregnation (10 min); it also maintained the initial release of urea approximate to 17 wt. \%.
Chinese quince fruit (CQF) contains abundant pectin; however, the pectin cannot be efficiently separated by conventional approaches because of strong lignin-carbohydrate complexes (LCC). In this study, to elucidate the structural characteristics of the original LCC formed by lignin and pectin in CQF, single and multiple enzymatic hydrolysis pretreatments were innovatively performed, and the resulting LCC preparations were comprehensively characterized using a series of techniques. The enzymatic hydrolysis pretreatments significantly increase the LCC yield, releasing LCC fractions with low molecular weights (Mw = 4660-8288 Da). LCC-4, isolated by pretreatment with cellulase plus xylanase, had the highest galacturonic acid content (15.5 \%), followed by LCC-2 (isolated by xylanase pretreatment) of 14.0 \%. In CQF, lignin develops lignin-carbohydrate (LC) bonds with pectin to form LCC, with phenyl-glycoside bond being the dominant linkage. Although the pectinase pretreatment reduced the pectin content, signals of the LC linkages in the 2D-HSQC spectra were enhanced. LCC-4 could be considered as the most representative of the original LCC in CQF due to its high pectin content and multiple LCC signals in the 2D-HSQC spectrum. The structural understanding of the original LCC in CQF will lay a foundation for designing appropriate methods for extracting pectin from CQF.
Due to increasing population and industrialization, the demand of energy is increasing day by day. Simultaneously, the worldwide bio-ethanol production is increasing constantly. The maize, sugarcane and sugar beets are major traditional agricultural crops used as bio-ethanol production but these crops are unable to meet the global demand of bio-ethanol production due to their primary value of food and feed. Hence, cellulosic materials such as agro-residues are attractive feedstock for bio-ethanol production. The cellulosic material is the most abundant biomass and agro-residues on the earth. Bio-ethanol from agro-residues could be a promising technology that involves four processes of pre-treatment, enzymatic hydrolysis, fermentation and distillation. These processes have several challenges and limitations such as biomass transport and handling, and efficient pre-treatment process for removing the lignin from the lignocellulosic agro-residues. Proper pre-treatment process may increase the concentrations of fermentable sugars after enzymatic hydrolysis, thereby improving the efficiency of the whole process. Others, efficient microbes and genetically modified microbes may also enhance the enzymatic hydrolysis. Conversion of cellulose to ethanol requires some new pre-treatment, enzymatic and fermentation technologies, to make the whole process cost effective. In this review, we have discussed about current technologies for sustainable bioethanol production from agro-residues. (C) 2014 Elsevier Ltd. All rights reserved.
A novel system (Oregon State University High Solids Reactor; OSU-HSR) was designed and constructed for enzymatic hydrolysis at ultrahigh solids content (40\%) by promoting better mixing using low energy consumption in a horizontal reactor with a new impeller design and a controllable feeding unit. System performance was evaluated using separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) methodologies. Using the dilute acid pretreated wheat straw as the substrate in the OSU-HSR system, the highest glucose (219.7 g/L) and ethanol (127.1 g/L) concentrations were achieved with the use of the SHF method while the highest ethanol concentration using SSF method was 134.5 g/L. The SSF method increased the return on investment to 12.21\% with an estimated global warming potential of 54.5 g CO2 eq/MJ Ethanol. The OSU-HSR successfully provided effective mixing and different fed-batch schemes, and can be used for efficient biochemical conversion of lignocellulosic biomass into bio-chemicals and biofuels.
Over the past few decades modern technologies have been developed and adopted to improve sugarcane processing. These improvements have not only reduced operating and production costs but have also helped increase productivity and profitability. Separation in a flotation clarifier is performed by generating adequate bubbles and sustaining a suitable environment for these bubbles to adhere to the impurities to be removed. Due to the presence of air, the density of flocs formed by mixing bubbles and impurities is lower than that of liquids. Buoyancy causes the flocs to surge to the surface, forming a layer of scum that is relatively easy to remove. A clarifier used in a sugar factory has a unilateral discharge. There is a ring inside, with 24 2-inch-diameter holes. Because the outlet is one-sided, the control is not ideal. This study presents the outcomes attained from a numerical analysis of the full-scale flow in a clarifier. The results were validated by comparing the numerical results with experimental results. The average flow rate from the four outlets of the proposed geometry was 2399 kg/h, with an error of less than 1\% compared with base case geometry. The main governing equations used during simulations of the juice clarifier were the continuity equation and the momentum equation commonly known as Navier-Stokes equations. The turbulent modeling approach standard k-epsilon was adopted. The values of k and epsilon are calculated using turbulence kinetic energy (k) equation and dissipation rate (epsilon) equations, respectively.
Three microorganisms were cultured to investigate their decolorizing activity on mixtures of 2 types of model brown pigment and 2 types of browned food. The mixture of model brown pigments of the Maillard reaction type and phenol type was not decolorized by cultivation with Coriolus versicolor IFO 30340, but it was decolorized by Paecilomyces canadensis NC-1 and by Streptomyces werraensis TT 14. The immobilized mycelia of C. versicolor IFO 30340 and P. canadensis NC-1 were incubated simultaneously or successively with each mixture of 2 types of browned food. It was found that the mixed culture of these 2 mycelia showed a higher decolorization rate than their successive culture.
In this work, curaua fibers were used in the reinforcement of a high-density (HDPE) thermoplastic matrix. The polyethylene used was obtained by polymerization of ethene produced from sugarcane ethanol. This polymer, also called high-density biopolyethylene (HDBPE), was prepared from a natural source material. The aim was to contribute to developing materials which could lead to smaller release of CO2 into the atmosphere in comparison to other materials. Additionally, liquid hydroxylatedpolybutadiene (LHPB) was added to the composite formulation, aiming at improving resistance to crack spreading during impact. The fibers and their composites were characterized by several techniques, such as scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and thermal gravimetry (TG). The composites were also characterized by dynamic mechanical thermal analysis (DMTA), mechanical properties (flexural and impact strength), and water absorption. The presence of curaua fibers reduced some of the properties of HDBPE, such as flexural and impact strength. DMTA indicated a more rigid material with the fibers incorporated. The addition of LHPB to the formulation was efficient, leading to greater impact strength for the HDBPE/LHPB/Fiber composite, as compared to the HDBPE/Fiber composite.
The utilization of agricultural biomass for production of electric power can help to reduce the environmental emissions while achieving energy security and sustainable development. This paper presents a methodology for estimating the power production potential of agricultural biomass in a country. Further, the methodology has been applied to develop a roadmap for producing reliable power in India. The present study reveals that about 650 Mt/year of agricultural biomass is generated in India, while about one-third of this has been found to be surplus for energy applications. The cereal crops have major contribution (64.60\%) in production of surplus biomass followed by sugarcane (24.60\%) and cotton (10.68\%). The energy potential of these resources is of the order of 3.72 EJ, which represents a significant proportion of the primary energy consumption in the country. These biomass resources can produce electric power of 23-35 GW depending upon the efficiency of thermal conversion. The delivery of biomass to the plants and selection of appropriate technology have been found as the major issues that need to be resolved carefully. In the end, the study summarizes various technological options for biomass collection and utilization that can be used for producing clean and consistent power supply. (C) 2016 Elsevier Ltd. All rights reserved.
This study evaluated two hydrolysis strategies that involve a two-step and a one-pot process for the hydrolysis of cellulose. The two-step process consisted of cellulose pretreatment with deep eutectic solvent, followed by hydrolysis promoted by the carbon-based solid acid catalyst. The obtained results showed that the xylose and glucose yields were 33.9\% and 6.9\%, respectively, from corn stover based on this two-step strategy with ChCl center dot Formic acid used as the pretreatment solvent. For one-pot hydrolysis, side reactions occurred and less glucose accumulated in the reaction system. In this case, the maximum achieved glucose yield was 21.1\% for the hydrolysis of microcrystalline cellulose.
Bioethanol is currently the only alternative to gasoline that can be used immediately without having to make any significant changes in the way fuel is distributed. In addition, the carbon dioxide (CO2) released during the combustion of bioethanol is the same as that used by the plant in the atmosphere for its growth, so it does not participate in the increase of the greenhouse effect. Bioethanol can be obtained by fermentation of plants containing sucrose (beet, sugar cane.) or starch (wheat, corn.). However, large-scale use of bioethanol implies the use of very large agricultural surfaces for maize or sugarcane production. Lignocellulosic biomass (LCB) such as agricultural residues for the production of bioethanol seems to be a solution to this problem due to its high availability and low cost even if its growth still faces technological difficulties. In this review, we present an overview of lignocellulosic biomass, the different methods of pretreatment of LCB and the various fermentation processes that can be used to produce bioethanol from LCB.
The dependence of Nigerian Government on foreign technology for oil spill cleanup in its water bodies does not add local content value in the development of the Nation's economy. Acetylation of natural cellulose gives a material with high sorption capacity for oil in water. This research investigates crude oil sorption from water using acetylated and unacetylated lignocellulose. Oil palm empty fruit bunch (OPEFB) and cocoa pod (CP) were acetylated under mild conditions. The acetylated (modified) and unacetylated (unmodified) sorbents were used to sorb oil from water, and their sorption capacities and mechanisms were compared. Paired t test showed there was significant difference in the sorption capacities of modified and unmodified sorbents. Sorption of oil from water was found to be time and concentration dependent. Equilibrium studies showed that CP has higher sorption capacity than OPEFB and acetylation enhanced the crude sorption capacities of the sorbents. Crude oil sorption from water is a monolayer process that might have progressed from multilayer processes. Kinetic studies showed that sorption of crude oil by the sorbents was diffusion-controlled with the aid of physisorption and chemisorption mechanisms. Fourier transform infrared and scanning electron microscope analyses showed clear evidence of successful acetylation and oil sorption.
Sustainable development in cassava starch industries is hampered by high cost and environmental burdens associated with the business-as-usual (BAU) waste management strategies. In BAU, starch wastewater \& bagasse wastes are anaerobically digested to produce biogas for starch drying with the digestate getting disposed into watercourses while the cassava stalks are burnt. Converting the wastes into high-value bio-products in an integrated cassava wastes biorefinery (CWB) could enhance the economic exploitation while reducing the environmental burdens of the wastes. Five simulated CWBs and the BAUhave been assessed and compared using simulations in SimaPro and a percentage sustainability index (PSI) estimation tool to identify product integration schemes that support the development of sustainable CWBs. The CWB scenarios included (I) combined heat \& power, with (II) hexosebioethanol, (III) pentose \& hexose-bioethanol, (IV) pentose-bioethanol + glucose syrup, and (V) pentosebioethanol + succinic acid. The environmental impacts generally increased with the number of product integrations within the biorefinery gate boundaries. However, accounting for avoided emissions from the corresponding fossil-products, the CWBs show higher emission savings than the BAU. The PSIs for the CWBs show that scenarios (I)-(II) favour the economic dimension over the environment dimension and vice versa for scenarios (III)-(V) and the BAU. Based on the substantial net power (-148-363 kW h/1 t feedstock) and fossil emission reduction potentials, implementation of green power tariffs could enhance the economic dimension for near-term applications of the CWBs. Thus, the CWBs should be explored for their potential to enhance sustainable industrial developments in cassava starch industries. (c) 2020 Elsevier Ltd. All rights reserved.
In this article, the geographical location and availability of the most important crop residues generated in Mexico over the last 10 years (2008-2017) were determined. This study estimates the gross number of residues for the four most important cultivars in Mexico named conventional residues (CRs) such as corn, wheat, sorghum, and barley, and estimates were also made for regionally important crops identified as nonconventional residues (NCRs) such as coffee, sugarcane, and beans. The total and sustainable energy potentials (TEP and SEP) for agricultural residues were calculated, in similar way the butanol and electricity production potentials were also calculated if these residues were processed under a nonconventional biorefinery scheme; the calculated availability of crop residues was 59,059,666 t/year, thus demonstrating that Mexico could have great potential for bioenergy production. The estimated TEP was 1,787,241,249 PJ/year, and the SEP was 78,724,689 PJ/year. The production of butanol and its production cost were calculated for the main crop residues; the butanol volume ranged from 7348 to 161,610 t/day, and the volume of crops of regional importance ranged from 6461.9 to 151,389 t/day. The minimum butanol production cost was 2000 t/day of feedstock. The surplus electricity was determined for all crop residues.
A Bacillus spp. strain isolated from a honey sample in Morillos (Salta, Argentina) was phylogenetically characterized as B. subtilis subsp. subtilis Mori2. The strain was administered to bee colonies as a monoculture in one litre of sugarcane syrup (125 g/L) at a final concentration of 10 5 spores/mL to evaluate the bee colony performance. The treated colony was monitored, and any changes were compared with the control hives. All conditions were identical (weather, nourishment and supervision), except for the Bacillus spore supplement. The new nourishment, which was administered monthly from May to December 2010, was accepted by the bees and consumed within ca. 24-48 h. Photograph records and statistic analyses revealed significant differences in the open and operculated brood areas between the treated and control groups. The status of the colony improved after the second administration of the Bacillus spores until the end of the experiment. A higher number of bees were counted in the treated groups (26\% more than the control) with respect to the initial number. Furthermore, at the time of harvest, honey storage in the treated hives was 17\% higher than in the control hives. In addition, spore counts of both Nosema sp. and Varroa sp. foretica in treated hives were lower than in the control hives. These results with experimental hives would indicate that B. subtilis subsp. subtilis Mori2 favoured the performance of bees; firstly, because the micro-organism stimulated the queen's egg laying, translating into a higher number of bees and consequently more honey. Secondly, because it reduced the prevalence of two important bee diseases worldwide: nosemosis and varroosis.
Recent developments in chemical pretreatments of lignocellulosic biomass using polyols as co-solvents (e.g., glycerol and ethylene glycol) at temperatures less than 100 degrees C may allow the effective use of thermostable and non-thermostable cellulases in situ during the saccharification process. The potential of biomass saccharifying enzymes, endoglucanases (EG) from a thermophilic bacterium (Thermotoga maritima) and a mesophilic fungus (Trichoderma longibrachiatum), to retain their activity in aqueous buffer, acidified glycerol, and acidified ethylene glycol used as co-solvents at pretreatment temperatures at or below 100 C were examined. The results show that despite its origin, T. longibrachiatum EG (Tl-EG) retained 75\% of its activity after exposure to 100 degrees C for 5 min in aqueous buffer while T. maritima EG (Tm-EG) retained only 5\% activity. However, at 90 degrees C both enzymes retained over 87\% of their activity. In acidified (0.1\% (w/w) H2SO4) glycerol, Tl-EG retained similar activity (80\%) to that obtained in glycerol alone, while Tm-EG retained only 35\%. With acidified ethylene glycol under these conditions, both Tl-EG and Tm-EG retained 36\% of their activity. The results therefore show that Tl-EG is more stable in both acidified glycerol and ethylene glycol than Tm-EG. A preliminary kinetic study showed that pure glycerol improved the thermal stability of Tl-EG but destabilized Tm-EG, relative to the buffer solution. The half-lives of both Tl-EG and Tm-EG are 4.5 min in acidified glycerol, indicating that the effectiveness of these enzymes under typical pretreatment times of greater than 15 min will be considerably diminished. Attempts have been made to explain the differences in the results obtained between the two enzymes. (C) 2014 Elsevier Inc. All rights reserved.
In the Kanto region in Japan, the possibilities of running a bio-ethanol plant from rice straw has been assessed and sorghum production has been considered as a necessary part of the system. Two field experiments were conducted in 2012 and 2013 at the NARO-Agricultural Research Center in Tsukuba, Ibaraki to estimate yielding ability of sorghum in the Kanto region. Two cultivars of sweet sorghum and one of grain sorghum were sown using a pneumatic seeder. Above-ground dry matter ( DM) yield ranged from 1.03 to 1.82 kg m(-2) for the sorgo type cultivars and from 0.70 to 1.18 kg m(-2) for the grain type cultivar. The observed yields were lower than the simulated potential yields, i.e., 1.61 to 2.66 kg m(-2), indicating that biomass production was restricted in this study. Stem brix values for the sweet sorghum cultivars were generally low (3.3-16.2\%) compared with the values reported in the literature. It appears that there is still room to improve the field management of sorghum to minimize the gap between the potential and actual production observed in these experiments.
Degradation of spent wash waste is a very essential but challenging task in the indian sugarcane distillery industry because of its awfully acidic pH, and intense brown colour with a strong unpleasant odour. Prior to discharge in the environment, its degradation using an efficient and cost effective method is important. A photo-catalytic degradation route could be a simple, cost effective alternative to conventional degradation processes. Cu-doped TiO2 was synthesised using a facile sol gel assisted hydrothermal method at various temperatures such as 120, 150 and 180 degrees C. Cu-TiO2 with doping concentrations of 0.5 to 5\% were synthesized using the hydrothermal method. The physico-chemical properties of the synthesised Cu-TiO2 were investigated by using various characterization techniques. UV-visible analysis shows a red shift in the absorption wavelength in the case of Cu-TiO2 as compared with bare TiO2. Structural and morphological analysis confirms the formation of anatase TiO2 with a nano-orthorhomb like morphology. The photocatalytic performance of the TiO2 and Cu doped TiO2 samples was evaluated for degradation of spent wash colour under natural solar light irradiation. Among all the Cu-TiO2 samples, 1\% Cu-TiO2 synthesized at 150 degrees C exhibited the maximum degradation efficiency with almost 59\% degradation of the spent wash in 5 h. The molecular weight of the colour compounds after degradation was monitored using gel permeation chromatography (GPC). The GPC fractions show low, medium, and high molecular weight coloured compounds with a strong hypsochromic shift. Identification of the compounds in each of the GPC fractions was studied using liquid chromatography mass spectrometry quadrupole time of flight (LC-MS Q-TOF).
In this study, the theoretically obtainable bioethanol production potential is estimated from the use of cacao residues in Ecuador, through the formulation of a mathematical model of the acid hydrolysis in cellulose of cacao husks and its conversion to ethanol by fermentation. Methodologically, the study was based on official documentation on the national and provincial amount of residual biomass of this crop, and on a kinetic model adapted to the case under study. An amount of 8.28 Mml of bioethanol was obtained, whose mixture with extra gasoline, at a ratio of 5:95 v/v, results in the Ecopais E5C gasoline. Production of 166 Mml of E5C was estimated, corresponding to 10 \% of the national production for the year 2017 and 56 \% of the production for the year 2014, year in which the residual biomass of cacao was estimated. The coastal region contributes with 71 \% of the national bioethanol and E5C production, led by the province of Guayas, in which E5 gasoline represents 25 \% of its consumption in 2017. It is concluded that this production route of bioethanol is an attractive diversification option of the current production route based on the cultivation of sugarcane, adding value to residual biomass that is currently discarded. The theoretical results constitute the basis for more detailed studies in those provinces that combine a high potential for cacao residues and increasing consumption of E5 but must be complemented with experimental research to corroborate their validity and provide elements that determine the viability of the bioethanol production route studied.
The development of the construction sector has created a deficit and constraints on natural building materials. The ecological impact of the construction material has been the subject of several investigations. About 40\% of all CO2 emissions originate from the construction and use of buildings, 15\% of which are associated with the production of construction materials. Therefore, it has been critical that the construction industry shift towards a greener approach to building construction. In addition, the excessive use of natural and river sand (likely used as fine aggregate in concrete) adversely affects environmental sustainability. In addition, the generation of agricultural residues/agro-waste imposes adverse ecological effects. Agro-waste is inevitably generated and burned after harvest to clean up the landfill. Agro-waste such as paddy husk, sugarcane, and red gram crops generate 10-15 times more than the actual products. Indeed, to meet the demand for building construction materials, it is preferably necessary to adopt native and eco-friendly alternate construction materials. Agro-waste has shown the perspective of sustainable alternative materials to be applied in building constructions. In this work, we have deliberated the various potential applications of agro-waste in building constructions. Also, we have conferred the evaluation of the physical, thermo-mechanical, methodological, and ecological impact. The application of agricultural wastes has been demonstrated to be a commercially viable technological solution for building construction materials that could ease the use of natural resources with energy safety.
Purpose - Agricultural food residues (agro-residues) receive low economic returns and experience disposal problems. The food production and processing is often not configured to supply agro-residues for production of bioenergy needed in food processing. The feasibility of utilising agro-residues through advances in postharvest technology for sustainable bioenergy conversion is reviewed. The paper aims to discuss this issue. Design/methodology/approach - Agro-residues from maize, sugarcane and potatoes in five African countries were assessed from secondary data to identify suitable conversion technologies, energy products and configurations of bioenergy plants for applications in postharvest food processing. Findings - Strategic alignment of postharvest technology to bioenergy production systems is vital to advancing both food production and bioenergy that benefit rural communities in Africa. High economic returns are possible when the bioenergy plants are either annexure to existing agro-processing operations or operate as a biorefinery. Research limitations/implications - Assessment of energy self-sufficiency of food production and processing systems is required. Practical implications - Agro-residues for bioenergy production require investments in infrastructure for storage, transportation and processing of the residues, and development of new risk management techniques. Social implications - The rural communities will be energy secure resulting in food security through reduced postharvest losses and increased agricultural productivity. Originality/value - The study stimulates innovative thinking in establishing sustainable bioenergy systems for food processes.
Lignin is one of the main obstacles for enzymatic hydrolysis, which can be selectively removed by hydrogen peroxide-acetic acid pretreatment (HPAC). In this work, the effects of sulfuric acid concentration on chemical composition, structural features, physical properties and enzymatic digestibility of HPAC pretreated poplar were investigated. The increased H2SO4 dosage enhanced the lignin removal of HPAC-pretreated poplar, resulting in the increased accessibility and decreased hydrophobicity. A satisfying glucose yield (91.84\%) was obtained from HPAC pretreated poplar (100 mM H2SO4) at 5 FPU/g DM of cellulase loading with the addition of xylanase (30 U/g DM) and Tween 80 (3 g/L). The increment of H2SO4 concentration promoted the yield of xylooligo-saccharides from 0.69\% to 20.45\% and monosaccharides from 5.76\% to 92.89\% respectively by two-step enzymatic hydrolysis. This work demonstrated that HPAC pretreatment played a critical role in efficient utilization of poplar carbohydrates by enzymatic hydrolysis.
In the present work, on the basis of literature and experimental data, some correlations for ultrasound-assisted dissolution of lignin and hemicelluloses from the lignocellulosic raw material were defined in Aspen Plus. as function of the applied power and length of the ultrasound treatment. The dissolution yield of these biomass components was represented against the applied acoustic energy, taking into account the volume of solvent-solid treated in each case, making possible the scale-up of US-power consumption in a simulated biorefinery pretreatment process. The proposed ultrasound-assisted process was techno-economically evaluated in terms of process yield and utilities requirement. Furthermore, energetic and exergetic analyses were performed in order to evaluate the profitability of the simulated ultrasound-assisted biomass fractionation processes.
Behaviour of plant material to mechanical compression depends on the physical properties of plant stalks and their resistance to compressive force. Rind with a high content of lignocellulosic fiber is a potential material for structural strength of the crop that participates in transfer of the loading stresses. The purpose of the study was to calculate mechanical properties of Erianthus arundinaceus cane with rind and without rind. Consequently, force deformation and stress and strain of the cane samples were studied which enumerate the basic essential information to determine the mechanical properties of cane under mechanical compression testing condition. Erianthus arundinaceus is a crop gaining momentum due to its potential for renewable energy value. The various parameters related to mechanical compression was studied using Universal Testing Machine (UTM). It was found that the clone IK76-93 X SF 06-48 yielded the maximum compression load. Maximum displacement force 9.04 kN was required to compress the Erianthus stem with rind, and the minimum displacement force was enabled at 5.13 kN for the clone IK76-81 X GC04-09. The clones without rind exhibited the maximum displacement force at 9.04 kN for the clone IK76-93 X SF 06-48, and the minimum was for the clone IK76-81 X GC04-09 at 3.86 kN. Information on the displacement profile of Erianthus clones gave a better understanding of the stem and rind behavior, and this would be helpful in designing crusher rollers for paper industry.
Biobutanol has been accepted as the preferred renewable, bio-based additive or replacement for petroleum based fuels. The production of biobutanol has, however, encountered low productivity and titres due to a high toxicity of butanol to the bacteria. This leads to an energy intensive distillation step. Gas stripping has been presented as a method of good potential because of its simplicity and clean operation, with the ability to concentrate the product by several fold. However, these investigations have lacked rigorous analysis of energy requirements, with the energy required at best being estimated using simplified assumptions. A detailed assessment of the energy requirements for gas stripping is presented in this work. This includes a rigorous analysis of the key operating variables of 21 experimental mass balance data sets from 16 investigations in the literature. Higher butanol concentrations in the culture and higher stripping temperatures are shown to be the two most significant parameters influencing the energy efficiency of the process. Gas stripping with distillation consumes 34.2 to 380 MJ/kg butanol and is 41-370\% less energy efficient than the use of distillation only for product recovery. Hence an integrated analysis of the production and separation steps is essential to determine overall process benefits. (C) 2018 Elsevier B.V. All rights reserved.
Pressmud is one of the most abundant wastes produced in the sugarcane industry; however, far too little attention has been paid to it as a reactive material for pollutant removal. This paper investigates the potential use of the composted pressmud for Cd(2+)removal and considers the possible remobilization of the ion after the use and subsequent disposal of this material. Characterization and adsorption analyses (batch equilibrium and kinetic) were carried out in addition to desorption and bioaccessibility assays. The pressmud revealed promising adsorption characteristics, including a high specific surface area (SSA) (236.1 m(2) g(-1)) and the presence of oxygen surface functional groups. The batch equilibrium data exhibit a better fit with the Langmuir isotherm model, assuming a monolayer adsorption capacity of 12.063 mg g(-1), and for kinetic data, the pseudosecond-order model satisfactorily suited the adsorption. The equilibrium time was attained rapidly at lower concentrations (within 30 min), increasing to 180 min at 500 mg L-1, due to the contribution of the intraparticle diffusion process. According to the desorption and bioaccessibility tests, pressmud is capable of maintaining the element at the binding sites, although the Cd(2+)adsorbed by the material is almost in its bioaccessible form, which supports the need of the correct handling after use. The results indicate that pressmud may be a promising reactive material for Cd(2+)adsorption, identifying upcycling opportunities for this low-cost and renewable waste.
Stillage is the main wastewater from ethanol production, generated specifically in the step of distillation. Regardless the feedstock, stillage contains high concentrations of organic matter, potassium and sulfates, as well as acidic and corrosive characteristics. Currently almost the entire volume of stillage generated in Brazilian distilleries is directed to the fertigation of sugarcane fields, due to its fertilizer character. However, the polluting potential of stillage characterizes its land disposal as problematic, considering probable negative impacts on the soil structure and water resources in case of excessive dosages. Since the literature lacks critical content describing clearly the cons related to the reuse of stillage in agriculture in the long-term, this review aimed to assess the real polluting potential of stillage, and the implications of its land disposal and/or discharge into water bodies. Evidence from the literature indicate that the main obstacles to reuse stillage in natura include risks of soil salinization; clogging of pores, reduction in the microbial activity and the significant depletion of dissolved oxygen concentrations in water bodies; contamination per nitrates and eutrophication; soil structure destabilization due to high concentrations of potassium and sodium; and, possible acidification of soil and water resources, considering the low pH of stillage (similar to 4,5). Toxic metals, such as cadmium, lead, copper, chromium and nickel, were also identified in concentrations above the recommended limits in stillage samples, increasing risks to human health (e.g. carcinogenic potential) and to crops (e.g. productivity loss). In short, although some studies report benefits from the land application of stillage, its treatment prior to disposal is essential to make fertigation an environmentally suitable practice. (C) 2014 Elsevier Ltd. All rights reserved.
Lignocellulosic biomass plays a vital role in the global shift away from the utilisation of non-renewable petrochemical resources. An emerging class of biomass-derived material is nanocellulose, which are typically generated from the deconstruction of cellulose bundles within the cell wall of terrestrial and aquatic plants, either in the form of cellulose nanocrystals (CNCs) or cellulose nanofibres (CNFs). However, the utilisation of biomass has an inherent challenge associated with product variability, both in terms of the starting feedstock properties, the wide range of processing routes available to generate nanocellulose, and the fabrication of nanocellulose into a diverse range of different product formats. As a result, it is difficult to accurately characterise and benchmark the wide variety of nanocellulose materials described within the literature. To address this challenge, this study presents a threefold benchmarking assessment of CNF-based material, including: (1) CNFs generated from different biomass sources (sorghum, banana, sugarcane, spinifex, and softwood); (2) CNFs generated through different mechanical processing methods (Silverson mixing, twin-screw extrusion, bead milling, and high pressure homogenisation); and (3) Energy-standardised nanopaper mechanical performance presented within applicable literature studies. The biomass benchmarking study highlighted sorghum and banana stem as comparatively sustainable biomass feedstock, while the mechanical process benchmarking study highlighted twin-screw extrusion as a promising fibrillation method with relatively low energy consumption. Lastly, the nanopaper benchmarking study aided in the visualisation of the nanopaper research landscape. Overall, sample benchmarking in this manner provides greater insight into the mechanisms driving nanocellulose material performance and processing sustainability.
Sudan has rich sources of lignocellulose materials from agricultural waste that have potential to be used as a papermaking furnish following adequate chemical compositions, elemental analysis, fibre dimensions, and morphology of millet stalks and date palm leaves. Paper sheet properties from the various pulps made were investigated, and it was found that there was no difference in the polysaccharide (cellulose and hemicelluloses) content between millet stalks and date palm leaves, although millet stalks had a high lignin content of 18.20\% relative to date palm leaves' content of 15.34\%. Moreover, millet stalks showed a high pulp yield (42.04\%) with a viscosity of 665 mL/g compared to that (34.43\%, 551 mL/g) and (38.50\% and 534 mL/g) of date palm leaves and the blend, respectively. Papers produced from date palm leaves and millet stalk blends showed better physical properties compared to that of pure millet stalks and date palm leaves. The Scanning Electron Microscopy (SEM) analysis showed that fibres in the blend were more closely packed than that of the pure millet stalks and date palm leaves fibers. Based on their physical and chemical composition properties, millet stalks and date palm leaves have a high potential as a furnish for pulp and papermaking.
Ozone is a powerful oxidant and is reactive toward lignin. Ozone can be used as an oxidant in pre-treatment process of lignocellulose material without producing any toxic residues nor making structural changes in cellulose and hemicellulose during ozonolysis process. This study aims to evaluate the effectiveness of ozone for the delignification of oil palm empty fruit bunch (OPEFB). The effect of 20. 40 and 60 mesh particle size. 30, 40 and 50\% moisture content, and 30. 45 and 60 minute reaction time as well as their interactions. on lignin degradation, holocellulose content and reducing sugar concentration is investigated using response surface methodologies (RSM) with Design Expert 10. The total number of pre-treatment variations is determined by Box Behnken. The results show that ozonolysis is an effective method for delignifying lignin up to 63.86\% and for increasing cellulose up to 40.95\%. The ozonolysis process is able to degrade lignin and hemicellulose without decreasing the cellulose. The optimum condition of lignin degradation after the ozonolysis pre-treatment occurs at the condition with 40 mesh particle size, 50\% moisture content and 30 minute reaction time. Enzymatic hydrolysis of OPEFB which has underwent ozonolysis pre-treatment can increase the concentration of reducing sugar. The optimum condition for lignin degradation is 42.42\% and the reducing sugar concentration of 0.40 g / L is determined by the condition with 40 mesh particle size, 30\% moisture content and 39.6 minute reaction time.
Biomass based energy generation is one of the major focus areas of renewable energy programs in India. The strength of India's biomass resources mostly lies in the agricultural sector. A large quantity of crop residue biomass is generated in India. However, crop residue biomasses are distributed resources with variation in spatio-temporal availability and its characteristics. Competing uses of residues also vary geographically. Therefore, local biomass databases are important for decentralized bioenergy programs. However, in India, state wise crop level biomass database is limited. The present paper assessed crop residue biomass and subsequently bioenergy potential in all the 28 states of India using crop statistics and standard procedure. A total of 39 residues from 26 crops cultivated in India are considered for the study. Overall, India produces 686 MT gross crop residue biomass on annual basis, of which 234 MT (34\% of gross) are estimated as surplus for bioenergy generation. At state level, Uttar Pradesh produces the highest amount of crop residue amongst all the 28 states. Amongst all the crops, sugarcane produces the highest amount of surplus residue followed by rice. The estimated annual bioenergy potential from the surplus crop residue biomass is 4.15 EJ, equivalent to 17\% of India's total primary energy consumption. There exists variation from 679 MJ (West Bengal) to 16,840 MJ (Punjab) of per capita crop residue bioenergy potential amongst the states of India. The information generated in this study is expected to be useful for decentralized crop residue based energy planning by the states of India which in turn would positively influence the overall renewable energy growth in India. (C) 2014 Elsevier Ltd. All rights reserved.
The aim of this study was to verify the viability of lignocellulosic substrates to obtain renewable energy source, through characterization of the cellulolytic complex, which was obtained by solid state fermentation using Trichoderma viride. Enzymatic activity of the cellulosic complex was measured during saccharification of substrates filter paper, eucalyptus sawdust, and corncob, and compared with the activity of commercial cellulase. The characterization of the enzymes was performed by a 2(2) Full Factorial Design, where the pH and temperature were the variables of study. Enzymatic saccharification of different substrates appearedviable until 12 to be viable until 12 h; after this period the activity decreased for both enzymatic forms (cellulolytic complex and commercial cellulase). The enzymatic activity of the commercial cellulase was favored with the use of corncob as substrate, while the cellulolytic complex does not show any difference in its specificity by the substrates studied. The largest activities of both enzymes were obtained in the temperature and pH range between 40 degrees C and 50 degrees C and 4.8 and 5.2, respectively. The cellulolytic complex obtained appeared to be viable for the saccharification of lignocellulosic residues compared with the commercial cellulase.
It is crucial to predict the characteristics of pyrolytic bio-oil accurately for its application, but the prediction results are greatly influenced by biomass compositions and pyrolysis conditions. In this work, different biomass compositions analysis (chemical compositions, ultimate and proximate analysis) and pyrolysis conditions (particle size, heating rate and pyrolysis temperature) were successfully used as input to analyze the characteristics of bio-oil by machine learning method. The model based on ultimate analysis is better for regression analysis of the yield, viscosity and oxygen-carbon ratio (O/C) of bio-oil. The model based on chemical compositions is better for regression analysis of calorific value and hydrogen-carbon ratio (H/C) of bio-oil. Moreover, relative error analysis and scatter diagrams were used to analyze the predicted results. In addition, the analysis of partial dependence diagram shows the influence of various factors and the interactions on the target variables. This study provides feasible thinking for the prediction of the characteristics of bio-oil obtained by biomass with different compositions under different pyrolysis conditions.
Acid hydrolysis is an essential step in converting polysaccharides to monosaccharides for the production of fuels and chemicals. The prehydrolysis liquor (PHL) from the kraft-based dissolving pulp production process contains mainly oligosugars with a minor amount of monosugars. In this study, the influence of process conditions, including the sulfuric acid concentration, temperature, and time on the PHL hydrolysis was thoroughly investigated in order to get maximum monosugar concentration with minimal degradation of sugars. The maximum monosugar concentration was obtained at 130 degrees C for 20 min when the hydrolysis was carried out with 1.78\% H2SO4. A high acid concentration (3.33\%) increased furfural formation and decreased the monosugar concentration. Acetic acid is generated from the acetyl groups bound to the dissolved hemicelluloses, resulting in a significant increase in the acetic acid concentration in the PHL.
Hemicellulose isolated from DmM was converted to novel functional biopolymers by maleylation using maleic anhydride as reactant and LiOH as catalyst. The reaction was performed under various temperatures, times, and the amounts of catalyst and maleic anhydride on the degree substitution (DS) of products were discussed. Comparison of the reaction in different media was discussed in detail. The product had the maximum degree of substitution (DS) of 0.75. Novel functional polymers containing with carbon-carbon double bond and carboxyl groups could be confirmed by C-13 NMR spectroscopy. The behavior of novel hemicellulosic derivatives was monitored by means of thermogravimetry (TG) and differential thermal analysis (DTA). It was found that the products with a high DS had a lower thermal stability than the native hemicelluloses.
Biobutanol has been emerging as a renewable replacement to overcome fossil fuel limit due to its attractive qualities. The waste resources utilization is an economically feasible and eco-friendly way to produce biobutanol. In this work, the potential of butanol fermentation with sweet potato residue (SPR) obtained from ethanol fermentation was evaluated. To assist sugar release for butanol production by Clostridia acetobutylicum, a pretreatment approach with dilute sulfuric acid was established via response surface methodology. The maximum butanol concentration of 3.77 g/L was obtained at the optimal conditions of pretreatment at 1\% (v/v) dilute sulfuric acid, and 115celcius for 30 min. Detoxifying the hydrolysate with XAD-4 resin significantly enhanced butanol fermentation performance, while adding nutritional supplements had no significant influence. The stability of the fermentation process was verified by the 2 L-scale of fermentation, resulting in 7.96 g/L of butanol, 13.42 g/L h of Acetone-Butanol-Ethanol (ABE), and 0.34 g/g of ABE yield, respectively. This study demonstrates a bio-refinery strategy of conversion from waste biomass to energy, confirms the feasibility of utilizing the cost saving SPR as feedstock to produce butanol through fermentation, and provides a novel approach for minimization of environmental pollution.
This study discusses the application of microwave-based heating for the pretreatment of biomass material, with Pennisetum purpureum selected for pretreatment. The Taguchi method was used to plan optimization experiments for the pretreatment parameter levels, and to measure the dynamic responses. With a low number of experiments, this study analyzed and determined a parameter combination in which Pennisetum purpureum can be rapidly heated to 190 degrees C. The experimental results suggested that the optimal parameter combination is: vessel capacity of 150 mL (level 2), heating power of 0.5 kW (level 1), and mass of Pennisetum purpureum of 5 g (level 1). The mass of Pennisetum purpureum is a key factor affecting system performance. An eight-order ARX model (Auto-Regressive eXogeneous) was representative of the actual system performance, and the fit was 99.13\%. The results proved that microwave-based heating, with the assistance of the Taguchi method for pretreatment of the biomass material, can reduce the parameter combination variations.
Steam explosion (150-200 degrees C, 5-30 min) was performed on a commercial cellulose presented in two configurations (fiberized and compact sheet) and its effect on their chemical and physical properties was studied, along with the influence of two different preservation methods (acetone drying and freezing) after pretreatment. No degradation compounds were produced during pretreatment, although solid recovery (R-S) decreased with temperature from 90\% to 62\%. Similar particle size and surface conditions (increased porosity) were found for both types of pretreated samples despite the extremely different initial configuration. Crystallinity diminished for 150 degrees C samples, but 200 degrees C pretreatment promoted recrystallization. Pretreatment also reduced polymerization degree, although enzymatic accessibility did not improve. Both acetone and freezing processes extremely affected cellulose properties. Acetone drying counterbalanced crystallinity and enzymatic accessibility variations of pretreated samples, while decreasing polymerization degree. Freezing dramatically decreased enzymatic accessibility of pretreated samples down to 15.8\%.
This study aims to isolate cellulose nanofibers from locally abundant pomelo fruit. The peels were subjected to alkali treatment (NaOH) with different concentrations and soaking times. Acid hydrolysis was also carried out to obtain an aqueous suspension of nanocellulose. The treated cellulose fibers were characterized by various methods. Alkali treatment was able to remove noncellulosic constituents. Microscopy techniques yielded morphology of elementary fibers with a compact structure with both micro- and nano-scaled fibers. An improved onset of degradation was likely caused by an increase in crystallinity evidenced by X-ray diffractometry (XRD). Acid hydrolysis could successfully individualize cellulose nanofibers as observed by transmission electron microscopy (TEM).
This study aims to isolate cellulose nanofibers from locally abundant pomelo fruit. Only the inner, soft peels were selected for investigation. The peels were subjected to alkali treatment (NaOH) with different concentrations and soaking times. Acid hydrolysis was also carried out to obtain an aqueous suspension of nanocellulose. The treated cellulose fibers were characterized by various methods. The effect of alkali treatment was initially confirmed by Fourier Transformed Infrared (FTIR) Spectra which displayed disappearance of several peaks belonging to non-cellulosic materials. The sharpening of the absorption at around 914 cm(-1) is attributed the beta-glycosidic linkages between the sugar units in cellulose. Alkali treatment also helped eliminate the noncellulosic constituents via reduction in the 1240 and 1750 cm(-1) peak. Thermogravimetric (TG) analysis revealed an improved onset of degradation likely caused by an increase in crystallinity evidenced by X-ray diffractometry (XRD) through the presence of two well-defined reflections characteristic of cellulose. The morphological and structural characterization by Scanning electron microscopy (SEM) still revealed a compact structure even after alkali treatment. However, acid hydrolysis was successful in individualizing cellulose nanofibers as observed by transmission electron microscopy (TEM). The diameter of these nanofibers was in the 10 - 20 nm range with various lengths. https://www.scientific.net/AMR.747.363.pdf
Bio-degradation of crop residues viz. cane trash, paddy trash, wheat trash and PMC utilizing Trichoderma species was studied for 90 days under pit condition. Treatments with urea and dung, inoculation by fungi Trichoderma increased N, P, K, S content in the resultant compost consistently in either of the residues having highest at 90 days. Likewise, organic-C and C: N ratio decrease substantially in the residues and exhibited minimum at the end of composting. Among the organics decomposition followed the order PMC > wheat trash > paddy trash > cane trash according to decrease in their C: N ratio. PMC, wheat, paddy and cane trashes needed a minimum of 30, 60, 60, 90 days respectively, for conversion into good quality compost by this process. Degradation of the crop residues involved narrowing down of the C: N ratio by urea solution applied followed by microbial decomposition by the Trichoderma. This study can be subjected to mass scale composting of rural or urban wastes and can be extended to the in situ decomposition of the crop residues viz. cane, paddy and wheat trashes left after mechanical or combine harvesting in the field and thus would elevate soil fertility for sustainable crop production safeguarding the environment being polluted by trash burning impacts.
Excessive use of fossil fuels results in the rapid depletion of non-renewable fossil energy resources, a rise in fuel cost, and an uncontrolled emission of greenhouse gases which causes a severe threat to the environment. Bio-fuels are being scrutinized as substitutes for current high -pollutant fuels obtained from conventional sources. To meet the global demands, it becomes necessary to find an alternate source of fuel which is bioethanol. In this work, a strategy to promote ethanol production from Leftover Cooked Rice (LCR) by comparing the different types of hydrolysis was proposed. Process integration comprised of mechanical pretreatment of the leftover cooked rice followed by hydrolysis which was then followed by fermentation. The food wastes of weight 50g taken in each of the 3 fermenters were subjected to acid hydrolysis, enzyme hydrolysis, and combined hydrolysis respectively. Commercially available Baker's yeast (Saccharomyces cerevisiae) was used for the fermentation process. The fermented samples were subjected to distillation to separate the bioethanol from them. The amount of bioethanol obtained from combined hydrolysis, acid hydrolysis, and enzyme hydrolysis was 400ml, 150ml, and 350ml respectively. Qualitative analysis of ethanol was done by using the Jones reagent. Hence, bioethanol can be produced from leftover cooked rice using the yeast Saccharomyces cerevisiae.
Post COP-15, the push is to reduce coal dependence for electricity generation and GHG emissions from the national electrical grid. Phasing out coal-based thermal power plants (TPPs) does not favour India's economic and social interests. Therefore, it becomes imperative to make coal-based power plants clean. Biochar derived from crop residues has been considered a clean fuel and an economical substitute for coal. The present study investigated the biochar potential of crop residues from rice, wheat, maize and sugarcane cultivation, accounting for 89\% of total agro production, for coal replacement in TPPs using primary \& secondary data and ArcGIS for mapping agro-residue collection point and TPP. Results show that biochar produced from the identified agro resources in the temperature range of 400 C-500 C are suitable for cofiring with coal. 121 MT surplus residues of the selected crops could produce 40 MT biochar having 90 TWh electricity generation potential. Biochar produced from surplus residues is equivalent to 69 MT of coal, about 11\% of coal consumed annually in Indian TPPs. Also, biochar cofiring could reduce 165 MT annual CO2 emissions from coal-burning in TPPs, about 14\% of CO2 emissions by the energy sector and 7\% of overall CO2 emissions by India. Techno-economic analysis showed that the infrastructure development \& operation cost for the biochar conversion facility is in the range of 2-3 USD/MWh, which is significantly lower than that of the new biomass to electricity generation facility (43-53 USD/MWh). The results would provide baseline data for policy decisions to avoid net GHG emissions from TPPs, and site identification for additional infrastructure to develop alternative clean fuels for India's coal-based TPPs.
Rhizospheric bacteria possess the potential to colonize the root zone of plants and stimulate their growth through different mechanisms. The present study explored the competency of plant growth promoting rhizobacteria based bioformulations (bf) formed from Bacillus pumilus (BP-bf), Bacillus simplex (BS-bf) and Bacillus megaterium (BM-bf) on the growth, yield and nutrient status of two wheat genotypes (Raj 3765 and DBW 90). In vitro studies demonstrated that biopriming with bf significantly improves the vigor index and germination of seedlings whereas results varied with different bacterial bioformulations. A pot experiment for further validation of results was conducted in factorial design with these treatments: T1: control of DBW 90; T2: control of Raj 3765; T3: DBW 90 bioprimed with BP-bf; T4: Raj 3765 bioprimed with BP-bf; T5: DBW 90 bioprimed with BS-bf; T6: Raj 3765 bioprimed with BS-bf; T7: DBW 90 bioprimed with BM-bf; T8: Raj 3765 bioprimed with BM-bf. Results demonstrated that bf applied treatments exhibited significant (P <= 0.01) improved growth and yield over control. The grain yield ranged 3.48 to 6.61 g/pot in bf applied treatments and significantly (P <= 0.01) increased straw weight was also obtained in these treatments. Amongst all bioformulations, BM-bf triggered the highest growth and yields in both the wheat genotypes. Results also demonstrated that these bioformulations induced the nutrient uptake in both wheat genotypes. Wheat rhizospheric biological activity was also boosted by the application of these bioformulations as significantly (P <= 0.001) enhanced bacterial colonization and microbial enzymatic activities were found. The study advocates the ability of these plant growth promoting Bacillus based bioformulations to improve the growth, quality and productivity of different wheat genotypes.
Supercritical water gasification (SCWG) is a combined thermal decomposition and hydrolysis process for converting wet biomass feedstock with high water content potentially (80 wt\%) to syngas. The process bypasses the need for an energy intensive pre-drying step and also needs relatively shorter residence times (of the order of seconds to minutes) when compared to conventional gasification. The main target of SCWG is to obtain syngas rich in hydrogen whilst minimising char formation. In recent years, SCWG studies have advanced from using model compounds (e.g. glucose and cellulose) towards the use of real biomass and its waste (e.g. sugarcane trash). The use of biomass as a feedstock creates real opportunities for the technology since it is available in some form, regardless of location. This review discusses the findings from SCWG studies that have used real biomass as a feedstock. The effects of reaction temperature, pressure, residence time and feedstock concentration to the hydrogen yields are presented. The relationship between the main components in biomass (cellulose, hemicellulose and lignin) and hydrogen yields are also discussed. Homogeneous and heterogeneous catalysts have been used to enhance SCWG with real biomass feedstock and the benefits of these approaches are also considered. The economic benefits of running the catalytic SCWG at 400 degrees C compared to non-catalytic operation at 600 degrees C is evaluated. Reactor configuration and process conditions vary across the literature, and various authors describe the associated challenges (char formation and plugging, corrosion) as well as promising solutions to tackle these key challenges.
Effective pretreatment of wood pulp waste is important for enhancing enzymatic saccharification. For this reason, wet oxidation process conditions were considered with the hypothesis that the alkaline oxygen conditions would favor delignification and hydrolysis of lignocellulose. Enzymatic saccharification was greatly improved to 42.9\% in terms of reducing sugar yield under the conditions of pH = 10, oxygen pressure = 1.2 MPa, time = 15 min, and temperature = 195 degrees C. A total of 39\% of lignin and 73\% of hemicellulose were removed and dissolved into the hydrolyzate. Furthermore, the chemical structure, crystallinity, and morphology of the treated substrate were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM).
The rational valorization of lignin and its derivatives is a challenge in biorefinery because this biopolymer is one of the major source of aromatic moieties. Lignosulfonates are used to a lesser extent than lignin to prepare macromolecular materials. In the current study, sodium lignosulfonate (NaLS), which was either blended or not blended with OH-containing vegetable oil (i.e., castor oil (CO)), was reacted with diphenylmethane diisocyanate (MDI) to prepare polyurethane-type materials, such as lignopolyurethanes (i.e., CO/NaLS/MDI and NaLS/MDI, respectively). NaLS was oxypropylated (LS-Oxy) to increase its reactivity towards MDI. LS-Oxy was characterized and then used after being blended or not blended with CO to prepare lignopolyurethanes CO/LS-Oxy/MDI and LS-Oxy/MDI, respectively. These materials were characterized by infrared spectroscopy, thermogravimetry (TG), and dynamic mechanical thermoanalysis (DMA). The T-g values obtained from DMA (loss modulus peak) indicated that the lignopolyurethanes with an intermediate degree of cross-linking were obtained. In a final set of experiments and due to their potential application, the obtained lignopolyurethanes were reinforced with sisal fibers, and the impact strength, flexural properties and scanning electron microscopy (SEM) images of the materials were obtained. The results indicated that the presence of sisal fibers led to a significant improvement in the impact strength of the lignopolyurethanes, especially in those prepared from LS-Oxy {[
Understanding soil organic matter (SOM) dynamics is essential to employ management that contribute to the improvement of soil quality (SQ). The aim of this study was to characterize the SOM and evaluate the emission of mineralizable C (C-CO2) in different management systems. The soil was collected in five managed areas: exposed soil (ES), conventional tillage system (CTS), no-tillage system (NTS), permanent pasture (PP) and sugarcane (SC), in addition to a forest area (NF), in the layers of 0-5, 5-10, and 10-20 cm. Total organic carbon (TOC), physical-granulometric fractionation of SOM were performed, determining the contents and stocks of particulate organic matter (C-POM; StockPOM) and mineral organic matter (C-MOM; StockMOM), in addition to calculating SQ indices. In addition to C-CO2 emissions from the soil. The areas of PP and NTS presented the highest levels of TOC in the surface layer. The highest levels of C-MOM and StockMOM were observed in the PP area, besides higher CSI (carbon stock index), reaching 1.67 in the 10-20 cm layer. The areas of PP and SC were similar to the NF in all layers regarding CMI (carbon management index). In CTS, there were higher peaks in emissions and accumulation of C-CO2. It is evident that the improvements in the SQ in the areas of PP, SC, and NTS caused mainly by the deposition of plant material and by soil revolving not being performed. In the CTS, high emission peaks of C-CO2 show that the lack of conservation management practices contributes to the emission of greenhouse gases.
Sawdust (SD) and cotton-lignin blends (CLB) were acetylated and the effect of lignin type and content on thermoplastic properties of the acetate produced was studied. The lignin in samples did not significantly affect the degree of acetylation. An increase in acetyl groups of 1-3\% was observed in acetylated SD (ASD) unlike acetylated CLB (ACLB). Thermogravimetric analysis showed two thermal degradation zones; one at 190-200 degrees C and the other at 330-370 degrees C. The early degradation in ASD corresponds to galactoglucomannans while that in ACLB corresponds to the low-molecular-weight lignin. The second degradation is due to decomposition of cellulose acetate and high-molecular-weight lignin. DSC analysis showed homogeneous behaviour in ASD with only one glass transition temperature (T-g) at 170-180 degrees C, unlike ACLB that showed two T(g)s at 170-180 degrees C. Sawdust acetylation, taking advantage of its residual lignin, showed higher reactivity and miscibility as compared to the same material produced by adding previously extracted lignin on cotton. (C) 2015 Elsevier B.V. All rights reserved.
Using agricultural wastes as an alternative phosphorus (P) source has great prospects to improve soil P status. A 70-day incubation experiment was carried out to investigate the effects of superphosphate (SSP), poultry manure (PM), cattle manure (CM), maize straw (MS), and cattle bone meal (CB) with the same total P input on soil P availability and fractions in typical acidic (red soil) and alkaline (fluvo-aquic soil) soils. The results showed that in both fluvo-aquic and red soils, CM out-performed other P sources in improving soil P availability. Changes in soil Olsen-P (Delta Olsen-P) were greater in fluvo-aquic soils with SSP, PM and CM additions than in red soils. Among the different P sources used, only CM has increased the labile soil P fractions to levels similar to that with SSP. Compared with SSP, more monoester P and inositol hexakisphosphate were detected in soils amended with PM and CM. A structural equation model (SEM) analysis suggested that soil pH had a direct positive effect on the labile P fractions in the acidic red soil amended with different P sources. In summary, CM is a superior P source for increasing plant available soil P, with considerable practical implications for P recycling.
A strain with strong antifungal activity, Bacillus subtilis NS-174, was identified and the antifungal compounds were purified and structurally analyzed by high performance liquid chromatography-mass spectrometry/mass spectrometry (HPLC-MS/MS). The effects of the enzymatic hydrolysis and the fermentation strategies on production of the antifungal compounds were also investigated. The results showed that the antifungal compounds were characterized to be C-14 and C-15 bacillomycin D homologues (C(14-15)BDs). When 400 mL of the cellulase hydrolysates from the maize straws residues (CHMSRs) was fed into 1.0 L of the batch fermentation broth at 60 h, an output of C(14-15)BDs (OC(14-15)BDs) was obtained as 44.84 mg g(maize straws)(-1). Moreover, the fed-batch fermentation was beneficial for the increase of the transcriptional activities of C(14-15)BDs synthetase genes by up-regulating expression of comA, sigmaH and spo0A, which caused the elevation of C(14-15)BDs production. The present work provided an effective solution for lipopeptide production in Bacillus subtilis.
Burning agricultural waste emerged as a prominent air pollution source that is widely prevalent across the entire Indian subcontinent, primarily in the Northern states. Cereal crops (primarily rice and wheat) in the North and sugarcane residues in other parts of the country contribute majorly to the burning of waste biomass. Massive increase in various harmful gases, including sulfur compounds and particulate matter, from the burning agricultural residues is linked to increasing health conditions, grave diseases and lowering of life expectancy of people affected by this practice. This review outlines the existing strategies followed in managing the agricultural waste residues, primarily in India, their limitations, the sustainable biotechnological interventions for the same and the current state of affairs in the interventions proposed. Innovations in mechanical stubble removal techniques and real-time monitoring aided by artificial intelligence tools will go a long way in curing this practice. Two primary aspects that are being promoted and hold much scope are the sensitization of farmer community and other stakeholders, including policy makers, involved in the production and dissemination of these residues, and establishing a commercial, decentralized market for the residues generated. Generation of value products from stubble will be the most helpful intervention in ensuring a positive action by the farmers. Some of the potential commercial applications include use of crop residues in sustainable architecture, as packing materials for commercial products, for the production of building/roofing materials, conversion to biochar for various applications, for biofuel generation, as substrate in mushroom cultivation and as raw material in the process of fermentation for producing various enzymes and other products of commercial value. Government initiatives and support as well as private partnerships are vital for the success of the endeavors.
The enzymatic hydrolysis of cassava residue treated by a hot water (HW) pretreatment, an extreme-low acid (ELA) pretreatment, and an alkaline hydrogen peroxide (AHP) pretreatment was investigated. The results showed that the ELA pretreatment dissolved greater xylan and glucose quantities than the HW pretreatment under the same conditions, and the xylan and glucan contents of the pretreated substrate affected the subsequent cellulase hydrolysis. The conversion to glucose by cellulase hydrolysis reached 81.4\% after the HW pretreatment, while the glucose yields under the ELA and AHP pretreatment conditions were 78.3\% and 71.0\%, respectively. In addition, supplementation with xylanase improved cellulase efficiency. At an equal xylanase dosage, a higher glucose yield (i.e., 91.3\%) was achieved for the ELA-pretreated substrates that contained a lower xylan content. Xylanase supplementation in the AHP pretreatment had little effect on the glucose conversion. Finally, X-ray diffraction studies showed that the HW and ELA pretreatments increased the cassava residue crystallinity, while the AHP pretreatment had little effect.
Bioethanol is a liquid biofuel produced from the digestion of biomass and usable waste of organic origin. The objective of this research was to obtain bioethanol from carrot (Daucus carota) residues of the Peruvian Chantenay variety, with a high content of lignocellulosic substances. The in-batch process method of enzymatic hydrolysis, with Aspergillus niger amyloglucosidase, and fermentation, with Saccharomyces cerevisiae yeast, was applied. The ferment was steam distilled and chemically characterized. The process was evaluated by controlling pH and enzyme/yeast mass ratio through the response surface optimization. The optimum conditions for the best values of TSS and \% ethanol content for the distilled product were a time of 300 min, yeast/enzyme mass ratio of 24.0, and pH of 4.98. The results showed a significant decrease in sugars in the hydrolysis and fermentation stages, optimum alcohol content in the distilled product of 92.48\% (v/v), lower organic compound content, and net calorific value of 23.82 MJ/kg, which is higher than those reported in the literature.
A chemi-mechanical approach was used to extract cellulose nanofibres (CNFs) from waste mango wood scraps using a mild chemical treatment ensuring no acid hydrolysis. The dimensional analysis for CNFs has been done by taking into account both the microscopic and light scattering techniques. The FESEM (field emission scanning electron microscopy) analysis revealed the diameter of obtained CNFs in the range of 5-40 nm with an average diameter of approximately 12 nm. The AFM (atomic force microscopy) analysis gave a more precise average diameter value of 5 nm for the obtained CNFs. The aspect ratio as determined by applying mathematical calculations on the data revealed through dynamic and static light scattering techniques (DLS, SLS) was approximately 200. The characteristic shape determined by fractal dimension investigation from SLS measurement revealed the rod/thread like shape of CNFs at lower concentrations. (C) 2017 Elsevier Ltd. All rights reserved.
The objective was to evaluate the inclusion of macauba seed cake (MSC) meal in diets for growing rabbits by assessing their growth and slaughtering performance, haematological traits, nutritional contribution of caecotrophs, in vitro digestibility, degradability and fermentation parameters. A total of 88 rabbits were distributed to four groups with 22 animals each and fed diets containing 0, 50, 100 and 150g/kg of MSC, respectively. The in vitro assays were conducted employing cecum inoculum on the same dietary treatments. The inclusion of MSC yielded a quadratic effect on in vitro dry matter digestibility (p<0.001). The maximum amount of produced gas was raised linearly with the inclusion of MSC (p=0.016). MSC linearly reduced several variables as the nutritional contribution of caecotrophs in dry matter (p=0.017) and crude protein (p=0.014), live weight at 51 d (p=0.024), body weight gain (p=0.039), average daily feed intake (ADFI) (p=0.001) and feed conversion ratio (FCR) (p=0.007) in the first period evaluated (30-50 d); furthermore the ADFI and FCR the second (51-72 d) and whole period (30-72 d) (p<0.001). MSC addition caused a quadratic effect on white blood cells count (p=0.026) and a linear decrease of eosinophils (p=0.045). In conclusion, the inclusion of up to 150g/kg of MSC improves the in vitro digestibility and fermentation potential of the diets, reflecting on the ADFI and FCR of the animals, although adverse effects are observed on the weight of the commercial carcass and nutritive contribution of the caecotrophs.
Sixteen yeast isolates representing two novel species of the genus Sugiyamaella were obtained from passalid beetles, their galleries and rotting wood collected in three sites of Amazonian Forest in Brazil. Sequence analyses of the ITS -5.8S region and the D1/D2 domains of the large subunit rRNA gene showed that the first species, described here as Sugiyamaella amazoniana f. a., sp. nov. (holotype CBS 18112, MycoBank 847461) is phylogenetically related to S. bonitensis with these species differing by 37 nucleotide substitutions and six gaps in D1/D2 sequences. S. amazoniana is represented by nine isolates obtained from the guts of the passalid beetles Popilius marginatus, Veturius magdalenae, Veturius sinuosus and Spasalus aquinoi, a beetle gallery and rotting wood. The second species, Sugiyamaella bielyi f. a., sp. nov. (holotype CBS 18148, MycoBank 847463), is most phy-logenetically related to several undescribed Sugiyamaella species. S. bielyi is described based on seven isolates obtained from the guts of V. magdalenae and V. sinuosus, a beetle gallery and rotting wood. Both species appear to be associated with passalid beetles and their ecological niches in Amazonian biome.
The growing demand of construction around the world has led to the increased usage of concrete. However, conventional concrete-making materials are not entirely environmental-friendly and this has enthused research on seeking greener alternative for concrete production. In the past, extensive research works had been carried out to utilize farming waste materials such as those from palm oil, coconut, sugarcane as well as the paddy industry and these findings indicate potential of utilizing such materials in concrete. The re-use of the farming waste materials in concrete could reduce the dependency on conventional concrete-making material as well as minimizing the negative impact on the environment besides ensuring waste conservation and reduction in waste disposal from these sectors. In this paper, a review on the utilization of emerging alternative farming waste materials in concrete such as from the farming of bamboo, corn, wheat, olive, sisal, seashells and more is carried out with the aim of examining the benefits and shortcomings of using these materials. This review shows the possible usage of farming waste materials in different form in concrete, such as partial cement and aggregate replacement, as well as fibre reinforcement. The main finding from the paper is that although usage of farming waste materials resulted in lowering of some concrete properties, appropriate treatment methods and selection of the waste materials would enable the production of concrete with improved performance. The summary and discussion provided in this paper should provide new information and knowledge on a greater variety of farming waste materials which are suitable to be used for the production of a greener and sustainable concrete. (C) 2016 Elsevier Ltd. All rights reserved.
The present study involved the utilization of crushed glass as an auxiliary additive in the manufacture of cement stabilized fly ash (CSF) bricks. The bricks were made with 1:1 proportion of fly ash and sand stabilized with 20 \% cement. Crushed glass was used as replacement for the fine aggregate in increments of 10 \% up to 40 \% wherein the sand was completely replaced with crushed glass. The various mix proportions were then moulded into bricks with the addition of water by hand moulding method of forming the bricks and sun dried followed by sprinkle curing over a period of 21 days. The bricks were then subjected to compressive strength, water absorption and efflorescence tests to gauge its performance. The investigation revealed that the addition of crushed glass to the brick mix resulted in an increase in strength of the bricks, however, the maximum strength achieved could not achieve the strength of the control specimen. But the strength was higher than the minimum strength recommended by Bureau of Indian Standards (BIS) for stabilized blocks as well as burnt bricks. It also reduced the water absorption marginally while no efflorescence was seen in any of the combinations. A cost comparison revealed that the optimal combination with crushed glass was able reduce the cost of the brick by 20 \%.
New bio-adsorbent carbon materials were synthesized from the leaves and veins of Mucuna pruriens and Manihot esculenta plants, which are locally available in abundance. The synthesized carbons were activated using 0.01N HNO3. Surface area of the activated carbons from M. pruriens and M. esculenta plants was found to be quite high, i.e., 918 and 865 m(2)/g, respectively. Scanning electron microscopy analysis of the carbons reflects complex disorganized surface structures of different open pore sizes, shapes and dimensions. These properties of the newly synthesized activated carbons led to the development of a sand-supported carbon column, for its possible use in the removal of coliform bacteria and Escherichia coli (E. Coli) from raw water samples. The removal percentage of E. coli was found to be 100\% with both the types of carbon adsorbents, as confirmed from the McCardy most probable number table. Similarly, the removal percentage of coliform bacteria was found to be 99 and 98.7\% by M. pruriens and M. esculenta carbon columns, respectively. These activated carbons synthesized from locally available plants possess the characteristics of good low-cost adsorbents which can be easily used for the removal of bacteria from water by adsorption method.
Maximizing the amount of monomeric sugar yield from lignocellulosic materials requires an effective pretreatment process and identification of an optimal enzyme loading for cost-effectiveness. In this work, a microwave-diluted sulfuric acid pretreatment was applied prior to enzymatic hydrolysis of sago palm bark (SPB). Characterization of the solid fraction was completed before and after the pretreatment process. Analysis of SPB ash showed a presence of 6.8\% silica. There was a 32\% reduction in lignin content, an increased crystallinity from 29\% to 47\%, and clear damage and fragmentation to the surface structure of SPB after the pretreatment. Inhibitors were not detectable in the liquor after the microwave-acid pretreatment. The enzymatic hydrolysis of SPB was employed by adding 6 to 42 FPU/g of cellulase and 50 U/g of beta-glucosidase to identify the optimal cellulase loading at fixed beta-glucosidase loading. The maximum total monomeric sugar yield and total reducing sugar (using DNS method) at 77 mg/g and 378 mg/g were achieved using 24 FPU/g of cellulose, respectively. Thus, this enzyme loading can be recommended for further microwave-acid pretreatment and enzymatic hydrolysis of SPB.
In present study, Leptochloa fusca (Kallar grass) and Gossypium herbarium (cotton stalk) were treated with various concentrations of KOH (1, 1.5, 2, 2.5 and 3\%) for different soaking periods (6, 12, 24 and 48 h) to expose maximum cellulosic content. The results showed that maximum cellulose exposure and delignification was increased with the increase in concentration of alkali and soaking time. However, maximum cellulose content (Kallar grass 49.01 +/- 0.1\%, cotton stalk 56.12 +/- 0.1\%) was achieved with 2.5\% KOH at 24 h and a decline was observed as further increase in concentration of KOH (3\%). Moreover, maximum delignification (Kallar grass 66.2\%, 62.6 cotton stalk) was observed at 3\% KOH after 48 h of soaking period. However, these results showed adverse effect of higher concentration of alkali on holocellulose. The cellulosic content of Kallar grass and cotton stalk after pretreatment at suitable conditions indicated that these substrates could be used as promising substrates for saccharification process to the produced second generation biofuel.
This research establishes the optimal microwave-assisted alkali pretreatment (MAP) condition of cassava rhizome (CR) using response surface methodology with Box-Behnken design for enhanced enzymatic hydrolysis glucose yield. The pretreatment parameters included microwave power (300-900 W), irradiation time (5-15 min), and NaOH concentration (3\%-7\% w/v); and the enzymatic hydrolysis was 24 and 48 hr. Quadratic models were generated and statistical analysis performed to validate the adequacy of the models. The results indicated that the optimal MAP condition was 840 W microwave power, 9 min irradiation time, and 3\% w/v NaOH concentration. Under the optimal condition, the predicted and experimental glucose yields were 15.39 and 15.82 g/100 g native cassava rhizome (NCR) for 24 hr hydrolysis, and 16.40 and 16.95 g/100 g NCR for 48 hr hydrolysis, indicating good agreement. In addition, this study examined the effect of MAP on the physical characteristics and morphology of NCR and pretreated CR. The results showed significant structural changes in pretreated CR, indicating that MAP enhanced enzymatic accessibility and glucose yield.
Imidazolium-based ionic liquids (ILs), including 1-butyl-3-methylimidazolium chloride (BmimCl) and 1-allyl-3-methylimidazolium chloride (AmimCl), were used to improve the refining properties of pulps under mild conditions. Results showed that the macro appearance of pulps was virtually unchanged after pretreatment with ILs under mild conditions. In addition, chemical pulps pretreated with ILs are more suitable for pretreatment than chemimechanical pulps. Pretreatment with ILs facilitates the refining process by destroying hydrogen bonds, which exist extensively in fiber. At the same refining energy input, the Canada standard freeness (CSF) of refined pulp decreased with improved fiber quality. At identical CSF values, the energy consumed during refining significantly decreased because ILs pretreatment facilitated swelling and fibrillation. The viscosity of cellulose changed slightly after IL pretreatment. However, the crystallinity index and fines content decreased, and the micro appearance of the fiber surface changed. BmimCl has a stronger swelling influence on pulp than AmimCl under optimal conditions. (C) 2012 Elsevier Ltd. All rights reserved.
In the present study, palm fiber (PF) and palm fronds (PFN) were selected as local agricultural wastes for the extraction of different biopolymers (cellulose, hemicelluloses, and lignin) by alkaline sodium hydroxide (PF, 2.37\% NaOH at 86.5 degrees C for 1.6 h; PFN, 6\% NaOH at 90 degrees C for 1 h) and bioethanol production. The processes of extraction were optimized by the experimental design method of Taguchi. The total carbohydrates of PF and PFN obtained were 24.4\% and 31.0\%, respectively. In addition, the untreated palm fiber (UPF), untreated palm frond (UPFN), cellulose palm fibers (CPF), and cellulose palm fronds (CPFN) were subjected to enzymatic hydrolysis processes using crude enzymes and commercial enzymes at 48 degrees C and pH 5.5. The results indicate that the maximum reducing sugars used were CPF 229.90, CPFN 243.69, UPF 120.19, and UPFN 100.00 (mg/g), which were obtained at a crude enzyme loading. CPF and CPFN hydrolysates were then successfully converted into bioethanol by a separate enzymatic hydrolysis and fermentation by Saccharomyces cerevisiae. Anaerobic cultivation of the hydrolysates with S.cerevisiae resulted in 0.222 g/g and 0.213 g/g bioethanol in the case of CPF and CPFN, respectively. Optimization processes could be an innovative approach to the sustainable development of bioethanol production.
The dense lignocellulosic structure inherent in particleboard poses a challenge to its efficient energy utilization, necessitating pretreatment prior to use. This study is aimed at exploring an optimal ionic liquid pretreatment process to enhance the utilization efficiency of waste particleboard. Response surface methodology (RSM) and analysis of variance (ANOVA) were employed to investigate the effects of various parameters, including reaction time, temperature, and concentration of tetrabutylammonium hydroxide ({[
It is obvious that Iran agricultural industry, unlike Brazil and USA, cannot afford to provide conventional biomass, i.e. sugary or starchy biomass for bioethanol production, mainly due to climatic and geographic conditions. With some exception of date (fruit), first-generation ethanol production triggers food vs. fuel debates in Iran and put nation to hunger. Agricultural products including apple, barley, carrot, corn, grape, orange, potato, rice, sugar beet, sugarcane, and wheat are consumed domestically, exported, or even lost because of poor harvesting and processing conditions such as transportation or packaging. These products may alone generate 21.56 million ton per annum green wastes upon processing in the food industry. Every year about 5.4 billion liters of bioethanol can be produced by establishing second generation ethanol plants next to the food processing sectors. Seventy-seven-percent of this amount of bioethanol can easily support 5\% ethanol (E5) policy to phase out the consumption of 4.2 billion liters methyl tert-butyl ether (MTBE) for raising the octane number of gasoline in the country. If more comprehensive policy is adopted, larger quantities of lignocellulosic feedstocks can be gathered from agro as well as forestry practices. Second-generation bioethanol technology can help Iran to tackle air pollution in its big cities and to address the adverse effects of MTBE on its populations and ecosystem. The other advantages are improvement of fuel security, mitigation of climate change, and development of economy. The motivation can be created through passing a framework policy to cut fossil fuel subsidies, to mandate bioethanol blends in gasoline, and to impose carbon taxes. Development of coherent socially and environmentally relevant strategies and facilitation of investment in bioethanol industry are also necessary. (C) 2019 Elsevier Ltd. All rights reserved.
Melanoidin is a compound produced by food industries and distilleries, which has negative impacts on the water environment due to the high content of dissolved organic carbon and dark color. Consequently, this work aims to study the catalytic properties of multilayer graphene (MLG), molybdenum oxide (MoO2), and manganese ferrite (MnFe2O4) in the ozonation process to remove melanoidin from water solution. The results show that the reaction rate constant (k) of the melanoidin decolorization process using catalytic ozonation is 1.7 times higher than the non-catalytic ozonation process. The same results were observed for all catalytic materials with no significant difference among them. On the other hand, MLG was the most efficient catalyst in removing total organic carbon. The removal efficiency was 32\% for the non-catalytic ozonation process and 63\% for the catalytic ozonation using MLG. This increase in efficiency is attributed to a better production of hydroxyl radicals in the presence of MLG, which was confirmed using isopropanol as a radical scavenger. The efficiencies using MoO2 and MnFe2O4 were 46\% and 51\%, respectively. The results show that catalytic ozonation by MLG is a promising treatment for melanoidin removal.
To improve the saccharification efficiency of bulrush, the supplementary of metal chlorides in pretreatment of lignocellulose had been researched. The effect of metal chloride type and dosage on the ability of deep eutectic solvent (DES ChCl: Gly) pretreatment was evaluated by composition analysis of biomass, characterization analysis {[
Hemicelluloses were successively extracted from sweet sorghum by hot water, dioxane, DMSO, and different concentrations of NaOH between 0.5\% and 6.0\%. The yields of the seven fractions together accounted for 88.6\% of the original hemicelluloses. The obtained hemicellulosic subfractions were comprehensively investigated by both destructive methods such as alkaline nitrobenzene oxidation and acid hydrolysis and nondestructive techniques such as gel permeation chromatography, Fourier-transform infrared, C-13-nuclear magnetic resonance, and 2D-heteronuclear singular quantum correlation. Sugar composition studies showed that the water-soluble polysaccharides consisted mainly of glucose, while xylose, arabinose, and glucuronic acid were the major sugars in other hemicellulosic fractions. It was found that the hemicelluloses from sweet sorghum were l-arabino-(4-O-methyl-d-glucurono)-xylans. Comparison with the hemicellulosic fractions dissolved by the alkali treatment, the hemicellulosic fraction extracted by DMSO had lower molecular weight. In addition, it was also found that the hemicelluloses prepared by dioxane and DMSO were more branched since that they had higher nonxylose/xylose ratios than those extracted by the alkali treatment, which were more linear and contained higher amounts xylose. (c) 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42790.
The utilisation of microalgal biomass as feedstock for bioethanol production has been very promising owing to the large amounts of carbohydrates embedded in the physiology of the microalgal cell. This is coupled with the potential of microalgae to achieve targets required for high growth rate bioethanol production, climate change mitigation and economic growth. The high content of complex carbohydrates entrapped in the cell wall of the microalgae makes it essential to incorporate a pre-treatment stage to release and convert these complex carbohydrates into simple sugars prior to the fermentation process. Hence, this study explores the influence of acid exposure as a microalgal pre-treatment strategy for bioethanol production. Different parameters were investigated: acid concentration, temperature, microalgae loading and pre-treatment time. A central composite design technique was employed to optimize the acid pre-treatment conditions. Results showed that the highest bioethanol concentration obtained was 7.20 g/L and this was achieved when the pre-treatment step was performed with 15 g/L of microalgae at 140 degrees C using 1\% (v/v) of sulphuric acid for 30 min. In terms of ethanol yield, similar to 52 wt\% (g ethanol/g microalgae) maximum was obtained using 10 g/L of microalgae and 3\% (v/v) of sulphuric acid under 160 degrees C for 15 min. The statistical analysis revealed amongst the parameters investigated that temperature is the most critical factor during acid pre-treatment of microalgae for bioethanol production. (C) 2010 Elsevier Ltd. All rights reserved.
This study was aimed to assess the effect of pre-freeze addition of cysteine hydrochloride and glutathione (GSH) on post-thaw sperm functional parameters and field fertility. The experimental bulls (n = 6) aged 4-6 years were used for this study. A total of 36 ejaculates (six ejaculates per bull) were collected and divided into three groups, group I (control), group II (5 mM cysteine hydrochloride) and group III (5 mM GSH). The extended semen samples with and without additives were filled in mini straw using automatic filling and sealing machine and cryopreserved in liquid nitrogen. Post-freeze seminal traits were recorded after thawing at 37 degrees C for 30 s. The curvilinear velocity (VCL) and amplitude of lateral head displacement values were significantly (p < 0.05) higher in GSH than the cysteine and control groups. Post-thaw plasmalemma integrity was significantly (p < 0.01) higher in GSH group when compared to cysteine and control groups. The loss of acrosomal integrity was significantly (p < 0.01) lower in GSH than in cysteine and control groups. Addition of GSH non-significantly (p = 0.1) improved mitochondrial membrane potential (MMP) (per cent) than control group. This study indicates that the addition of cysteine and GSH suggestive (p = 0.08) of reducing lipid peroxide levels. The conception rate (\%) in glutathione group was significantly (p < 0.05) higher than that in cysteine (68 vs 58) and control (49) groups. The post-thaw sperm progressive forward motility (r = 0.4) had moderate, but no significant correlation with conception rate. However, post-thaw straight-line velocity (r = 0.7), loss of acrosomal integrity (r = -0.8) and MMP (r = 0.9) had significant (p < 0.05) correlation with field fertility. This study indicates that the use of glutathione as semen additive may be used for improving post-thaw semen quality and overall augmentation of pregnancy in cows.
Prolonged lag phase and reactor instability make methane yield description and prediction challenging in upset solid-state anaerobic digestion (SSAD). Seven kinetic models (first-order (FOM), modified first-order (MFOM), Fitzhugh (FzM), logistic (LM), modified logistic (MLM), Cone (CM), and modified Gompertz (MGM) were employed for treatment evaluation. The treatments were dairy manure blended with calcium pretreated stover (8\% Ca CSDM) or sodium pretreated corn stover (4\% Na CSDM) or 2\% aqueous ammonia pretreated corn stover (2\% NH4 CSDM), or 4\% aqueous ammonia pretreated corn stover (4\% NH4 CSDM). The LM, CM, MLM with MGM, and MGM best described methane yield for 4\% Na CSDM, 2\% NH4 CSDM, 4\% NH4 CSDM, and 8\% Ca CSDM, respectively. Optimal hydraulic retention time predicted for the least inhibited treatment, 8\% Ca CSDM, was 60 days. Therefore, non-hydrolysis rate limiting models (LM, MLM, FzM, MGM, and CM) could simulate methane yield, design of reactor's volume, and develop degradation rate models in full-scale SSAD. (c) 2020 Elsevier Ltd. All rights reserved.
Delignification of sawdust was studied using ultrasound assisted alkali peroxide approach using longitudinal horn for the first time and the efficacy compared with more commonly used configurations of ultrasonic reactors. Comparison with the conventional approach based on stirring has also been presented to establish the process intensification benefits. Effect of different operating parameters such as sodium carbonate concentration (0.1, 0.15, 0.2, 0.25 M), hydrogen peroxide concentration (0.2, 0.4, 0.6, 0.8, 1 M) and biomass loading (2, 4, 6, 8, 10 wt\%), on the efficacy of lignin extraction has been investigated for different ultrasonic reactors. The optimum conditions for probe type ultrasonic horn were established as 150 W, 50\% duty cycle and 80\% amplitude with optimum process conditions as Na2CO3 concentration as 0.2 M, H2O2 concentration as 1 M, biomass loading of 10 wt\% and operating time of 70 min. Longitudinal horn resulted in best efficacy (both in terms of yield and energy requirements) followed by ultrasonic horn and ultrasonic bath whereas the conventional approach was least effective. The obtained lignin was also analyzed using different characterization techniques. The presence of peaks at wavelength range of 875-817, 1123-1110, and at 1599 cm(-1) for the extracted sample confirmed the presence of lignin. Increase in the crystallinity index of the processed sample (maximum for longitudinal horn) also confirmed the lignin removal as lignin is amorphous in nature. Overall it has been concluded that ultrasound can be effectively used for delignification with longitudinal horn as best configuration.
Environmental considerations in recent times have led to increasing interest in naturally occurring lignocellulosic materials as they are abundant and biodegradable. Pearl Millet (PM) stalks are currently discarded in North India and add to agrowaste generation. In this study, raw stalk of PM was characterized for physicochemical properties such as composition, moisture content, water absorbency and thermal behaviour. Morphology and crystallinity were studied using scanning electron microscope and X-ray diffraction respectively. Pure cellulose, extracted from the stalk using an optimised process, was characterised similarly. XRD patterns indicate the presence of cellulose type I structure with crystallinity index of 32\% for raw stalk and 55\% for the purified material. Water absorbency was 10 g/g for raw and 13 g/g for extracted cellulose. Material was thermally stable up to 200 degrees C. These findings indicate that PM stalks may be used as an indigenous source of cellulose for the absorbent layer in hygiene products.
Finding supplements to wood and curbing environmental effects of waste disposal have become global topical issues. We investigated density, dimensional stability and bending properties of particleboards from mixed-wood sawdust and Cocos nucifera (coconut) husk fibres in respective mix ratios of 100\%: 0; 70\%: 30\%; 50\%: 50\%; and 0\%:100\% using cassava starch and urea-formaldehyde (UF) binders. 1993 BS EN protocols 310 (for density and bending properties) and 317 (for water absorption and thickness swelling) were employed. Particle sizes were 1- <= 3 mm based on sieving with 3 mm mesh. Density was low to medium range (approximate to 397-approximate to 666 kg/m(3)) though UF bonded boards were relatively and continuously higher with increased coconut fibres proportions compared to CS bonded ones. Also, UF bonded boards absorbed less water and exhibited dimensional stability relative to CS bonded boards. Bending strength of UF bonded boards was higher (MOEs ranging from approximate to 40\%. to 1097\%., and MORs being approximate to 125-652\% higher) compared to the CS bonded counterparts. Materials mix ratio, binder type and their interactions had significant effect (p < 0.01) on density, MOE, and MOR. In conclusion, producing particleboard from coconut fibre and mixed-wood sawdust is possible with CS and UF as binders, but 0\%W:100\%C mixed ratio exhibited better MOE and MOR. Hence, efforts should be made to convert Cocos nucifera husks and sawdust into particleboard production to make available more alternative/supplementary materials/products to wood to reduce deforestation rate and curtail the environmental problems associated with the residues' disposal.
This study investigates the sustainability of the first-generation ethanol production process using a water steam condensed stream reuse approach. Determination was made of the effective water collection of an autonomous distillery and opportunities for the reuse of water streams were identified. Given the importance of the distillation design and its impacts on sustainability, relevant problems and challenges are highlighted, and suggestions are made of ways to enhance the process. Simulations were carried out using the Aspen Plus simulator to perform mass and energy balances. Three case studies were investigated: distillation with use of a reboiler as heat source (Case I); conventional direct steam injection distillation (Case II); and distillation with mechanical vapour recompression (Case III). In all cases, environmental aspects were considered using WAR software and exergy concepts. A technical-economic evaluation of the distillation system was performed in order to identify the best design. The results showed that the use of closed circuits and water reuse streams provided an overall consumption of 673 L water/t of cane in the mill. This value is lower than the statutory limit of 1000 L/t of cane established for distilleries in the State of Sao Paulo. Furthermore, according to the results obtained using the WAR software and the concepts of exergy and renewability index, Case II and III were considered to provide worse environmental performance, compared to Case I. In addition, Case I achieved net revenue of US\$ 115 million, which was approximately 9\% and 12\% higher than achieved for Cases II and III, respectively. Therefore, it is environmentally and economically beneficial to employ a reboiler as a heat source in distillation systems, compared to conventional systems employed to produce bioethanol. (C) 2017 Elsevier Ltd. All rights reserved.
Choline chloride (ChCl) is the most common hydrogen acceptor (HBA) used in deep eutectic solvents (DES) due to its low toxicity and biodegradability. In this study, seven types of ChCl-based DESs were used for the pretreatment of Triarrhena lutarioriparia (TL), and the residues after pretreatment were subjected to enzymatic hydrolysis. Characterization techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transformed infrared (FTIR) spectroscopy were used to determine the physical and chemical properties of TL pretreated with DESs. The results demonstrated that ChCl-oxalic acid dihydrate (molar ratio of 2:1; CO2:1) exhibited a good pretreatment ability among the DESs types examined. The optimal TL pretreatment process with CO2:1 was obtained by uniform design (UD) experiments and comprised a solid-liquid ratio of 1:25, temperature of 110 degrees C, and time of 5 h, which achieved an enzymatic digestibility of 83.71 \%. Furthermore, the cellulose reservation, hemicelluloses removal, and lignin removal still remained over 86 \%, 80 \% and 67 \%, respectively, after being recycled five times. Overall, the CO2:1 pretreatment process was effective for the component separation and enzymatic hydrolysis of TL and will promote the development of a green biological refinery pretreatment process.
Bleached Kraft pulp (BKP) from Eucalyptus globulus and cotton xylan blends (CXB) was acetylated. The effects of xylan content on cellulose acetylation and the properties of the acetylated material were studied. An increase in xylan content caused a slight decrease in the degree of substitution (2.98 to 2.68 for CXB; 2.93 to 2.84 for BKP). Thermal analysis showed that the melting temperature also decreases from 268.0 to 188.8 degrees C for CXB and from 221.4 to 212.8 degrees C for BKP. Moreover, the solubility decreased due to the partial dissolution of acetylated xylans. The presence of xylans during Kraft pulp acetylation does not have a significant negative effect on the physical properties of the acetylated material, but the decrease in melting temperature was beneficial for the application of acetylated polymer as a natural internal plasticizer. This is considered to be an important argument for BKP utilization in the cellulose acetate manufacturing process. (C) 2014 Elsevier Ltd. All rights reserved.
Wastewater generated from distillery industries is a matter of great concern due to its dark brown color, high organic load and resistance to natural biodegradation. Therefore, enormous effort is needed to avoid the discharge of this highly polluted effluent into natural water bodies and their consequent contamination. However, the treatment of the ever-increasing quantities of distillery wastewater in a cost-effective and eco-friendly manner is very challenging. The current physicochemical techniques available are either costly, energy-intensive or involve toxic chemicals. Thus, there is an urgent need to complement the existing knowledge on the biodegradation of distillery effluent with valuable resource recovery to find an appropriate solution for its sustainable management. This review incorporates a summary of the problems associated with distillery wastewater with special attention towards major color-causing components present in it and the challenges they pose. Detailed examination of various bioremediation approaches used by researchers for the treatment of distillery effluent is also provided. Moreover, the review scrutinizes the utilization of distillery wastewater for valuable product recovery to reduce its environmental burden and ascribe value to it. The study might help researchers and policy makers to develop suitable strategies for the microbiological treatment of high organic load and color-containing wastewater generated from various industries along with resource recovery, a beneficial step in the direction of sustainable development and circular economy.
Pretreatment using an acid salt is a novel technology for biomass conversion, which not only improves the following enzymatic efficiency but also decreases the equipment corrosion. In the present work, MgCl2 was used as a pretreatment for enzymatic saccharification. After pretreatment, the solid substrate (SS) and pretreatment liquor (PL) were characterized, and the SS was enzymatically hydrolyzed to evaluate the conversion yield of cellulose (CYC). The results showed that the pretreatment using MgCl2 had a strong degradation effect on hemicellulose, whose removal rate was nearly 100\% in certain cases. After pretreatment, the efficiency of the enzymatic SS saccharification increased, such that the CYC was as high as 99.5\%. The degradation kinetics of hemicellulose and cellulose both followed first-order homogeneous reactions, and the reaction activation energies E-a were 46.63 kJ/mol and 82.26 kJ/mol, respectively. The suitable pretreatment conditions were as follows: 0.2 mol/L MgCl2 at 210 degrees C for 20 min.
A variety of protic ionic liquids (PILs) were utilized to extract lignin from black liquor (BL). The PILs and a control IL, {[
PurposeCorncob hydrolysate, feather hydrolysate waste (FHW) and glutamate mill waste (GMW) are inexpensive raw materials derived from agricultural waste biomass. The aim of the study was to optimize the production of surfactin from the xylose-rich corncob hydrolysate and low-cost residues rich in organic nitrogen using Bacillus subtilis BS-37.MethodsHydrolysis of corncob was carried out with 1.5\% H2SO4, FHW or GMW was used as nitrogen source to produce surfactin. Sugar compositions of corncob hydrolysate and surfactin titer were determined by HPLC. The dry weight method was used to measure biomass in fermentation broth.ResultsWe discovered that the efficient surfactin producer B. subtilis BS-37 can use xylose as sole carbon source, but the addition of organic nitrogen sources was essential for surfactin production. Consequently, the xylose-rich corncob hydrolysate and low-cost residues rich in organic nitrogen were used to produce surfactin. Strain BS-37 was able to tolerate significant concentrations of several inhibitory compounds found in corncob hydrolysate, whereby acetic acid even enhanced surfactin production. Furthermore, NaOH-neutralized corncob hydrolysate was more suitable for surfactin production than the traditional Ca(OH)(2)-neutralized feedstock.ConclusionsWe achieved a maximal surfactin yield of 523mg/L from NaOH-neutralized corncob hydrolysate and feather hydrolysate waste. Furthermore, the product contained 55.3\% of the most desirable surfactin isoform C-15. To our best knowledge, this is the first report of surfactin production with xylose as the main fermentable carbon source.
Schinus molle (SM) was investigated as a primary source of cellulose with the aim of discovering resources to generate cellulose nanofibers (CNF). The SM was put through a soda pulping process to purify the cellulose, and then, the fiber was treated with an enzymatic treatment. Then, a twin-screw extruder and/or masuko were utilized to help with fiber delamination during the nanofibrillation process. After the enzymatic treatment, the twin-screw extruder and masuko treatment give a yield of 49.6 and 50.2\%, respectively. The optical and atomic force microscopy, morfi, and polymerization degrees of prepared cellulosic materials were established. The pulp fibers, collected following each treatment stage, demonstrated that fiber characteristics such as length and crystallinity varied according to the used treatment (mechanical or enzymatic treatment). Obviously, the enzymic treatment resulted in shorter fibers and an increased degree of polymerization. However, the CNF obtained after enzymatic and extrusion treatment was achieved, and it gave 19 nm as the arithmetic width and a Young's modulus of 8.63 GPa.
Saccharum ravannae, known as ``Ekra{''
An attempt was made to apply the solid state fermentation (SSF))br the production of single cell protein (SCP) using oil free rice bran waste as substrate. A local isolate of Aspergillus niger, was used as protein source for the studies. Total proteins were extracted to estimate the mycelial biomass from the moldy bran. Carbonate-bicarbonate extraction buffer and a pH 10 was found to be most efficient among the buffers used for the extraction of the proteins from the organism. The effect of supplementation by various sources of nitrogen and mineral solution on the final biomass yield was compared. The influence of C/N ratio on the protein yield was also studied. Sodium nitrate at C/N ratio of 1.387 was found to be on effective nitrogen-supplementing source, as it gave the higher biomass yield.
The bioconversion of lignocellulosic wastes to value-added biosurfactants was investigated using a single flask to carry out both substrate pretreatment and biosurfactant production. Lignocellulosic wastes were added to an alkaline medium and autoclaved, which led to a combined alkaline and hydrothermal pretreatment. For bio-surfactant production, alkaliphilic Brevibacterium casei NK8 was added to the medium without pH neutralization. Among several lignocellulosic wastes, the media with corn husk, coconut oil cake, and defatted rice bran gave the highest biosurfactant concentrations (1.14-1.32 g L-1). These wastes provided a relatively high concentration of soluble substrates in the pretreated liquid, while solid residues swelled. The bacterium could use the pretreated liquid and solid residues for growth and biosurfactant production. The produced biosurfactants in cell-free broth could be applied directly or after lignin removal. The residual lignin decreased biosurfactant performance in terms of surface tension, contact angle, and oil displacement; conversely, lignin enhanced the biosurfactant emulsification capacity. Cell-free broths with and without lignin were appropriate for different tasks. Bio-surfactants synthesized from different lignocellulosic wastes were similar and were identified as a mixture of zwitterionic lipopeptides and phospholipids. The surface tension of the crude biosurfactant solution was extremely low, ranging between 25.9 and 27.6 mN m-1 over a wide range of pH values (1-11), salinities (2-10\% NaCl), and temperatures (4-121 C). In addition, biosurfactants as crude solution and cell-free broth with lignin showed lower phytotoxicity than the commercial surfactant Tween 80. These findings suggest a convenient method for manufacturing biosurfactants from lignocellulosic wastes.
A binary deep eutectic solvent consisting of choline chloride and glycerol (ChCl/Gly) is proven to be ineffective in lignocellulosic pretreatment, and arbitrarily screening coordination agents makes it difficult to directionally construct a valid solvent. This study investigated the designable diversity of ternary ChCl/Gly coordinated with various metal-salts by elucidating solvent properties and reaction characteristics. Alkaline/acidic strengths and hydrogen-bonding forces were key factors for component fractionation. Pretreatment performance was typically poor for solvents with few acidic sites and active protons (i.e., ChCl/Gly-KCl and MgCl2), as well as those with close proximity of H-bond donor and acceptor abilities (ChCl/Gly-ZnCl2). By contrast, strong alkaline ChCl/Gly-K2CO3 could achieved 72 \% of delignification with a remarkable holo-cellulose preservation (70.8-80.9 \%). Delignification underwent an independent rate-control of solvent diffusion and surface reaction with an endo-thermic nature (17.1 kJ/mol of Delta H and 20.3 kJ/mol of apparent activation energy). High temperature was beneficial for mitigating diffusion constraint at the initial pretreatment stage, maximally increasing the reaction rate by 7.7-fold. Moreover, Lewis acidic ChCl/Gly-FeCl3 (or AlCl3) removed 76-84.4 \% of hemicellulose and 47.6-61.9 \% of lignin while significantly deconstructing the aryl-ether bonds and beta-O-4 linkages. But for acidic ChCl/Gly solvents, biomass dissolution was inconformity with the independent diffusion/reaction-controlling process, owing to the excessive hemicellulose degradation and hydrolytic by-product formation (maximally 91 g/kg xylose and 4 g/kg furans). Based on the lignin structural characterization, the potential reaction mechanism related to solvent properties was proposed to develop efficient ternary coordinated deep eutectic solvents.
Liquefaction of high solid loadings of unpretreated corn stover pellets has been demonstrated with rheology of the resulting slurries enabling mixing and movement within biorefinery bioreactors. However, some forms of pelleted stover do not readily liquefy, so it is important to screen out lots of unsuitable pellets before processing is initiated. This work reports a laboratory assay that rapidly assesses whether pellets have the potential for enzyme-based liquefaction at high solids loadings. Twenty-eight pelleted corn stover (harvested at the same time and location) were analyzed using 20 mL enzyme solutions (3 FPU cellulase/ g biomass) at 30 \% w/v solids loading. Imaging together with measurement of reducing sugars were performed over 24-hours. Some samples formed concentrated slurries of 300 mg/mL (dry basis) in the small-scale assay, which was later confirmed in an agitated bioreactor. Also, the laboratory assay showed potential for optimizing enzyme formulations that could be employed for slurry formation.
Industrial processes require thermal energy in form of saturated steam. Cogeneration system in a process industry uses an industrial boiler to produce superheated steam, which is subsequently expanded in a condensing-extraction steam turbine. The extracted steam is sent to the process, and the remaining steam is condensed in a condenser. Since the extracted steam is superheated, it must be mixed with cooling water in a direct-contact heat exchanger before the resulting saturated steam is sent to the evaporation process. A more energy efficient method of desuperheating, which requires the replacement of the direct-contact heat exchanger with a non-contact heat exchanger, is investigated in this paper. Extracted superheated steam is desuperheated, and air temperature is increased in this heat exchanger. The performances of the conventional cogeneration system that uses direct-contact heat exchanger for desuperheating and the modified cogeneration system that uses non-contact heat exchanger for desuperheating are compared. Simulation results indicate that the modified cogeneration system is more energy efficient than the conventional cogeneration system because the power output of the modified cogeneration system is larger than that of the conventional cogeneration system under the same operating conditions. (C) 2020 The Author(s). Published by Elsevier Ltd.
The pretreatment of lignocellulosic material via steam explosion process can be used to decrease the energy and chemical consumption during pulping to obtain environmentally friendly building blocks and improve the quality of materials by reducing the hemicellulose content. The objective of this work was to optimize the extraction of building blocks (lignin and cellulose) from oil palm mesocarp fibers using steam explosion pretreatment, followed by acetosolv and bleaching. The experimental central composite design 2(2) was used to optimize the steam explosion procedure prior to the acetosolv and bleaching processes. Although steam explosion increased the cellulose pulp yield by 47 \% compared to without pretreatment (25 \% vs 17 \%), at 210 degrees C for 3 min, these conditions were not favorable for lignin extraction, which decreased from 56 \% without pretreatment to 46 \%. Pretreated cellulosic pulp had a higher purity, thermal stability, and crystallinity. Lignin with or without pretreatment showed similar characteristics. Our findings demonstrate that steam explosion is an efficient pretreatment for improving the characteristics of cellulosic pulp without affecting the quality of lignin, highlighting the potential use of these building blocks in the production of cellulose nanoparticles such as crystals and fibrils, as well as in the substitution of non-renewable phenols in resins.
Caesalpinia pulcherrima is a shrub with worldwide distribution used as an ornamental plant. In this study, we extracted a lignin from the C. pulcherrima leaves and investigated its biological functions. The lignin was characterized by FT-IR, UV-Vis, GPC, TGA and nuclear magnetic resonance (1H and C-13). The antioxidant activity was evaluated using phosphomolybdenum complexation methods (TAA), sequestration of DPPH and ABTS radicals, reducing power, formation of nitrite radical and iron chelating activity (Fe2+). Antifungal activity was made using Candida spp., Aspergillus spp. and Cryptococcus neoformans strains. Cytotoxicity, oxidative stress, and cytokine production were performed using mouse splenocytes. The lignin showed maximal UV-Vis at similar to 280 nm, 22.27 L/g.cm of absorptivity and, 2,503 kDa of molecular weight. Phenolic compounds (41.33 0.65 mg GAE/ g) and indications of a guaiacyl-syringyl-hydroxyphenyl (GSH)-type composition were found. Antioxidant activities of lignin to TAA (40 +/- 1.2\%) and to DPPH (16.9 +/- 0.2\%) was high and showed antifungal potential, especially against Candida spp. (IC50 = 31.3 Ng/mL) and C. neoformans (15.6 Ng/mL). In mouse splenocytes, the lignin was not cytotoxic and stimulated the cell proliferation and cytokine release. These results indicate that C. pulcherrima lignin has the potential to be used as antifungal and immunostimulant compound.(c) 2020 Elsevier B.V. All rights reserved.
The fungal community and the population of 16S rRNA, 18S rRNA and cellulose-degrading genes during the 30-day composting process of Chinese medicinal herbal residues were investigated using Illumina MiSeq and quantitative real-time PCR. An obvious succession of fungal communities occurred during the composting process. Unidentified fungi predominated in the raw materials. As composting progressed, Ascomycota became the most dominant phylum, with Aspergillus being the most dominant genus, and Aspergillus fumigatus making up 99.65\% of that genus. Because of the inoculation of cellulolytic fungi in the mature stage, the cellulose degradation rate in inoculation groups was faster and the relative abundances of Aspergillus and the glycoside hydrolase family 7 genes were significantly higher than those in the control groups. These indicated that the fungal inoculants facilitated the degradation of cellulose, increased cellulolytic fungi and optimized the community structure. (C) 2017 Published by Elsevier Ltd.
The analysis results of Klason lignin and structural carbohydrates determined by downscaled analysis methods using 50 mg and 5 mg biomass and glass microfiber filters for the filtration of acid-insoluble lignin, were compared to a conventional method using 300 mg biomass and ceramic crucibles. The usage of microfiber filters reduces space requirement in oven and furnace to a minimum and speeds up the filtration of Klason lignin about three-fold. Furthermore, tedious cleaning of crucibles is unnecessary which additionally increases the number of samples that can be analyzed in a given time frame. The analysis of 5 feedstocks comprising herbaceous, hard- and softwood, revealed no significant differences of hemicellulosic sugars between the 50 mg microfiber and the 300 mg crucible method. The 50 mg microfiber method resulted in Klason lignin values in the range of -6.1\% to +4.0\% (relative) and glucan values in the range of -0.8\% to +3.7\% (relative) of the values obtained with the 300 mg crucible method. The 50 mg microfiber method was highly reproducible with relative standard deviations (RSD\%) of 0.27-0.56\% (average 0.38\%) for Klason lignin and 0.54\%-1.46\% (average 1.01\%) for glucan. Compared to the 50 mg microfiber method, the 5 mg microfiber method resulted in similar deviations of Klason lignin and glucan from the 300 mg method values. However, the reproducibility was slightly lower. Overall, the 50 mg and 5 mg microfiber method reflected the actual biomass composition with sufficient accuracy and are therefore recommended as alternative methods or when downscaling of the analysis is required. (C) 2014 Elsevier Ltd. All rights reserved.
In present study, the substrate Gossypium herbaceum (cotton stalks) was treated with sodium hydroxide to investigate its greatest promising use as an economical substrate for bioethanol production. Initially, 2 mm mesh size cotton stalks were soaked in various concentrations of NaOH (1-3\%) for different soaking intervals of 2, 4, 6, 12, 24, and 48 h. The results showed that the cellulose content and delignification increased with the increase in the concentration of alkali and soaking time. However, the maximum cellulose and delignification (60.6\% and 51.5\%) were observed with 2.5\% NaOH after 24 h of soaking. In physiochemical pretreatment, the maximum cellulose content (73.19\%) was achieved with 2.5\% NaOH at 121 degrees C after 60 min while delignification was found to be 77.7\%. All these results of the present study indicate that a suitable concentration of alkali as well as an autoclaving period at specific temperature are very much crucial to expose the maximum cellulosic contents prior to employing cotton stalks as substrates for bio-fuel production.
Long fermentation time and high oxygen partial pressure were significant challenges for high ethanol productivity in solid state fermentation (SSF). In this study, the feasibility of N-2 periodic pulsation to improve ethanol productivity was investigated. Changes of CO2 concentration and water state distribution in N-2 periodic pulsation SSF were examined. A metabolic flux model was developed to understand the effect of N-2 periodic pulsation on ethanol production. The results indicated that ethanol productivity of 1.75 g/(L.h) in N-2 periodic pulsation group (NPPG) was 34.4\% higher than that in control group (CG) within 24 h. The maximum ethanol concentration and yield were 47.52 g/L and 70.80\% at 70\% moisture content, respectively. The CO2 concentration in NPPG was well below 5000 ppm at 21 h, which was much lower than 38,080 ppm in CG. Metabolic flux analysis revealed that the metabolic flux towards ethanol increased by 25\% with the application of N-2 periodic pulsation. These results confirmed that N-2 periodic pulsation is an effective method for improving ethanol production in solid state fermentation. (C) 2021 Published by Elsevier Ltd.
This study investigated the effect of xylanase-assisted alkaline pretreatment (XAP) on the extraction of cellulose nanocrystal (CNCs) from energy cane (EC). Different concentrations of xylanase were tested to estimate the optimal enzyme loading required for pretreatment. XAP reduced the bleaching step from 7 to 5 h, generating a material with 93\% whiteness index and a higher crystallinity index (CrI) than the alkaline-bleached fibers. A combined pretreatment using xylanase at 200 U/g removed 59 and 35\% of hemicellulose and lignin, respectively, that was present in the EC which was confirmed using Fourier transform infrared spectroscopy and scanning electron microscopy analysis. X-ray diffraction and transmission electron microscopy revealed the XAP material required a shorter time of acid hydrolysis (30 min) to generate CNCs with similar lengths and CrI values to those obtained using only the alkaline pretreatment. Therefore, the XAP offered an efficient and promising approach for the isolation of CNCs with less use of chemicals for the bleaching process and a shorter hydrolysis time.
Endophytic fungi inside a plant can degrade a portion of plant lignin and cellulose. Endophytic Penicillium is one of the industrial microorganisms with the advantage of producing enzymes with a complete enzyme system that can be secreted into the extracellular space. The natural evolution of ancient tree species from special natural geographic environments to screen out cellulase-producing strains with excellent characteristics provides a promising direction for future industrial enzymes. The present study successfully isolated and screened a novel fungal endophyte, Penicillium oxalicum R4, with higher cellulase activity from Taxus cuspidata. Under the optimized culture conditions obtained by a Box-Behnken design (BBD) and an artificial neural network-genetic algorithm (ANN-GA), yields of Filter Paperase (FPase), Carboxymethyl Cellulase (CMCase) and beta-glucosidase (beta GLase) produced by P. oxalicum R4 were 1.45, 5.27 and 6.35 U/mL, which were approximately 1.60-fold, 1.59-fold and 2.16-fold higher than those of the non-optimized culture, respectively. The discovery of cellulase-producing strains of endophytic fungi located in special natural geographic environments, such as Taxus cuspidata, which is known as a living plant fossil, provides new research directions for future industrial enzymes.
The objective of this study was to extract cellulose nanofibrils (CNFs) from dry softwood pulp through a simple and environmentally friendly physical method of refining pretreatment coupled with high shear homogenization. An optical microscopy (OM) clearly showed the morphological development from the cellulose fibers to CNFs under repeated shear forces. The morphology, structure and properties of the obtained CNFs were comprehensively investigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transformed infrared (FTIR) spectra, X-ray diffraction (XRD) and thermogravimetric (TG) analysis. The results indicated that the CNFs had diameters mainly ranged from 16 to 28 nm. Compared with the pulp fibers, the CNFs exhibited a slightly higher crystallinity and a lower thermal stability. Moreover, a novel nanopaper with high optical transparency was prepared from the obtained CNFs, and a possible mechanism for the high optical transparency was discussed. (C) 2013 Elsevier Ltd. All rights reserved.
The growth in the Humulus lupulus L. or hops industry, a perennial species, driven by demand from brewers has had annual revenue growth of 11.3\% since 2015 making it one of the fastest growing agricultural commodities in the Pacific Northwest (PNW). There is currently 85,000 MT per year of hop bine in the PNW available for paper making. The land dedicated to hop agriculture increased by 68\% from 2010 to 2019 in the Yakima Valley. The plant Humulus lupulus L. belongs to the same family as Cannabis sativa L., industrial hemp, which has seen practical use in both the paper industry and in the biobased development. The bulk density of the hop bine is low, 0.296 g/cm(3) and only 1.5 metric tons of bine is produced per acre each year. However, as crops allocated to production of renewable resources compete for land previously dedicated to food crops, the residual biomass from hop cultivation offers an inexpensive alternative source of renewable lignocellulosic biomass without cannibalizing a food crop. H. lupulus was characterized to evaluate the acceptability for use as a paper making fiber and for hydrolytic conversion to biobased products. The high carbohydrate content, 58\%, is similar to other lignocellulosic materials suitable for bioenergy feedstocks. The fiber has morphological characteristics similar to hardwood with length and width centered around 0.85 mm and 16.5 mu m, respectively. The tensile strength of the hop-made papers was 61\% greater than the industrial hemp made papers at the same refining level. This fiber presents a sustainable multi-use commodity with excellent application in biobased products and paper making which would otherwise be lost.
A two-part study on pretreatment and fed batch enzymatic hydrolysis of pretreated Tefraselmis suecica using a high initial biomass concentration was conducted. First, the effect of different pretreatment processes, i.e. microwave (MC), dilute alkaline (AK), and microwave-alkaline assisted (MAK) pretreatment, on enzymatic hydrolysis of T. suecica biomass was evaluated. Furthermore, high initial biomass concentration enzymatic hydrolysis improvement via a fed-batch strategy was performed. Among the pretreatments tested, the MAK pretreatment produced the highest sugar concentration at 9.83 +/- 0.24 mg/mL, corresponding to a conversion yield of up to 85.58\% of carbohydrate content available in the pretreated biomass. The solid fraction generated after pretreatment was characterized using Fourier transform infrared (FTIR) spectroscopy. The FTIR analysis revealed a significant change in the functional hydroxyl and acetyl groups of the biomass, which is favorable for enzymatic hydrolysis. Introducing an initial microalgal biomass concentration beyond 15\% (w/v) exhibited a low enzymatic hydrolysis yield. The fed-batch enzymatic hydrolysis strategy of the MAK pretreated T. suecica was further investigated by adding the substrate at different time intervals. The findings indicate that the fed-batch operation system could enhance sugar production and enzymatic hydrolysis yield one-fold.
In this work, a simplified and cost-effective chlorite pretreatment method to improve the hydrolysabiliy of biomass was developed. Compared to common used sodium chlorite-acetic acid (SCA) pretreatment (18.1\%), sodium chlorite (SC) pretreatment resulted in less xylan loss (7.8\%), thus led more carbohydrates retention. Moreover, the Chinese silvergrass pretreated by SC for 2 h achieved higher glucose yield (70.5\%) than the substrate pretreated by SCA under the same pretreatment conditions did (58.7\%), after 48 h enzymatic hydrolysis by cellulase. By synergistic action of cellulase and xylanase, the glucose yield of SC pretreated (12 h) samples reached to 93.5\% with 808.7 mg/g DM total reducing sugars yields. In addition, without the usage of acetic acid could decrease the process cost and result in less inhibitor generation in pretreatment process.
Uncontrolled management of agricultural wastes have strongly contributed to the increase of greenhouse emissions and pollution. On the other hand, these residues can be used as a sustainable source for the production of activated carbon. Currently, biomasses rich in lignin are the most widely used, due to the high yields and large surface areas attainable. The aim of this study is to understand the influence of each biomass component on activated carbon properties. Alpha-cellulose, xylan, kraft lignin, and mixtures with different ratios of the single components were used as model substances to represent biomass. These materials were pyrolyzed and subsequently activated with KOH to expand the surface area. TGA results showed no interaction between components during pyrolysis but there was a strong influence of the composition of the mixture on the activated carbon properties due to the different thermal stabilities of each char. The activated carbon with the largest apparent surface area was obtained from cellulose with 2220 m(2) g(-1) and pure xylan showed the lowest with 1950 m(2) g(-1). T-plot calculations showed that more than 90\% of the surface area was composed by micropores. To understand the microporosity, CO2 isotherms were measured. The surface areas calculated were lower but followed the same trend as those obtained from the isotherms with N-2. (C) 2016 Elsevier Ltd. All rights reserved.
Soju industrial biomass residue (SIBR) is a lignocellulosic agro-industrial biowaste available in large quantities in soju producing countries. In this study, an attempt was made to extract microcrystalline cellulose (MCC), a biopolymer from SIBR by controlled acid hydrolysis. X-ray diffraction analysis indicated the presence of cellulose I structure with two peaks around 2 theta = 15 and 22.5 degrees and increase in crystallinity after acid hydrolysis treatment. Fourier transform infrared analysis showed no significant chemical affect of the cellulose fragment. Thermo-gravimetric analysis reveals that the extracted MCC have a good thermal stability (319 degrees C). Dynamic light scattering studies confirmed the presence of MCC in micro range (126.4 nm) which was supported by transmission electron microscopy. The results of this work are useful for extracting valuable and widely applicable cellulose, and help solve management of SIBR in terms of disposal and pollution problems.
Thermogravimetric analysis, Gaussian-fit-peak model (GFPM), and distributed activation energy model (DAEM) were firstly used to explore the effect of anaerobic digestion on sequential pyrolysis kinetic of four organic solid wastes (OSW). Results showed that the OSW weight loss mainly occurred in the second pyrolysis stage relating to organic matter decomposition. Compared with raw substrate, the weight loss of corresponding digestate was lower in the range of 180-550 degrees C, but was higher in 550-900 degrees C. GFPM analysis revealed that organic components volatized at peak temperatures of 188-263, 373-401 and 420-462 degrees C had a faster degradation rate than those at 274-327 degrees C during anaerobic digestion. DAEM analysis showed that anaerobic digestion had discrepant effects on activation energy for four OSW pyrolysis, possibly because of their different organic composition. It requires further investigation for the special organic matter, i.e., protein-like and carbohydrate-like groups, to confirm the assumption. (C) 2016 Elsevier Ltd. All rights reserved.
In this paper, the effects of incorporation of sawdust waste on the properties of fired clay bricks were investigated. Clay bricks fabricated with 0\%, 2.5\%, 5\%, 7.5\%, and 10\% by weight of sawdust waste were tested. The clay brick specimens were firing at 900 degrees C, 1000 degrees C, and 1100 degrees C for study the water absorption, bulk density, apparent porosity, compressive strength, and thermal conductivity of the fired clay bricks. The experimental results found that the using of sawdust waste reduced the bulk density and compressive strength of the specimens. It was observed their apparent porosity ratios up to 30\% improved with increasing of sawdust waste up to 10\% by weight after firing at 900 degrees C. The compressive strength of bricks specimen with 2.5\% by weight of sawdust waste addition and fired at 1100 degrees C showed a higher than of value strength as required by ASTM C62-13a. In addition, the thermal conductivity of the porous fired clay bricks specimens with 2.5-10\% by weight sawdust waste addition produced at 1000 degrees C compared to the fired clay brick specimens without additive, decreased from 0.47 to 0.22 W/mK. The results thus showed that sawdust waste was a potential material for use as a pore former additive to raw clay-brick production.
Laboratory experiments have shown that aqueous ammonia soaking (AAS) is a promising treatment for increasing the methane yield of the solid fraction of manure (fibers). AMMONOX is a new concept based on the sustainable use of ammonia for enhancing biogas production at biogas plants digesting manure. The proposed process is based on an optimized AAS treatment of manure fibers in combination with an efficient ammonia recovery step. The enhancement of biogas production is achieved by enriching manure with AAS-treated fibers, or other lignocellulosic residues, while the ammonia recovered can be used for fulfilling the needs of the treatment itself. Excess of ammonia could be produced when ammonia is recovered from both the treated fibers and the digester effluent, which could be used for the reduction of NOx in biogas-based electricity generation by gas turbines. In this survey study, the importance of different factors affecting the performance of AAS of digested manure fibers was investigated in order to conclude on which variables to optimize. Principal component analysis of the present data was used for a preliminary analysis of effects. The temperature and the ammonia concentration during AAS were the most influencing variables in terms of methane yield under the conditions tested. Further experiments should be conducted in order to investigate the effect of shorter AAS duration than the ones tested (lower than 24 h) and for assessing the importance of the solid-to-liquid ratio in the treatment mixture; the follow-up campaign should be optimized with respect to possible interactions/correlated experimental factor effects.
This study investigated the use of palm oil fuel ash (POFA), a by-product of burning solid waste from palm oil production, as a clay replacement in brick manufacturing. Clay was thus replaced with 5\%, 10\%, 15\%, and 20\% POFA by weight in bricks produced in a local factory to study the feasibility of large-scale manufacturing. The physico-mechanical properties of these bricks (linear shrinkage, weight per unit area, compressive strength, and apparent porosity) were compared with those of conventional bricks without POFA. The thermal performances of the bricks were assessed by measuring the difference in temperature between their top and bottom surfaces during exposure to direct sunlight. The results of this study indicate that replacing clay with POFA reduced the linear shrinkage of the bricks. Furthermore, the weight per unit area and compressive strength of bricks containing higher replacement percentages of POFA decreased due to their increasingly porous structure. Replacing clay with up 10\% POFA still met the minimum compressive strength criteria of the Indonesian Industrial Standard for non-load-bearing wall materials (i.e., 2.5 N/mm(2) ). Furthermore, 10\% POFA bricks provided better thermal performance, exhibiting a temperature difference of about 6 degrees C compared to 2.5 degrees C for conventional bricks without POFA. Therefore, using 10\% POFA as a clay replacement in large-scale brick production can address POFA disposal problems, reduce clay consumption, and decrease energy demand for indoor cooling, yielding a more environmentally friendly clay brick.
Sunflower stalk was evaluated as a potential fiber source to make fluting paper using neutral sulfite semi-chemical pulping process, in comparison with Mazandaran wood and paper industry mill made hardwood-based neutral sulfite semi-chemical (NSSC) pulp. Sunflower stalk consists of two distinct fractions including inner bulky pith and outer woody wall. The stalk has to be de-pithed for the purpose of papermaking because of lower cellulose, and higher ash content in pith-containing stalk. The results of pulping showed that the rate of delignification in NSSC cooking of de-pithed sunflower stalk with 20\% lignin was surprisingly very low, despite of being a non-wood fiber source. However, sunflower stalk NSSC pulp showed very good response to refining and produced denser sheet due to lower digester yield and higher fiber flexibility coefficient, in comparison with Mazandaran wood and paper industry pulp sample. In addition, sunflower stalk pulp has been demonstrated to be an appropriate fiber source for making fluting paper at higher or comparable tensile-loaded strength properties such as tensile and burst, and higher compression-loaded strength properties including corrugated medium test and ring crush test. (C) 2016 Elsevier Ltd. All rights reserved.
The objective of the study was to determine the bromatological composition of the ammonification of oats hay subjected to four levels of urea and three of water. A completely randomized design was used with four repetitions in a 4x3 factorial scheme. The levels of urea (2, 4, 6\%, based on dry matter) and water (20, 30, 40\%) added were evaluated. The processed oats were stored in PVC microsilos of 10x60 cm for 60 days. At the opening of the silos, samples were collected to determine DM, CP, mineral matter (MM), NDF and ADF, plus hemicellulose by the difference between the latter components. The DM decreased linearly when using the water levels with 2, 4 and 6\% urea. The average CP content increased cubically with the addition of urea (14.52\%) in relation to urea-free silage (6.70\%) and decreased with water levels (11.89 vs. 9.92\%). There was no effect of the urea or water levels on the contents of NDF and ADF. The NDF of the ammonified oats with the levels of urea in combination with 20\% of water showed a negative linear effect (58.01 to 47.86\% of NDF). This same behavior was observed for hemicellulose (19.10 to 14.74\%). The MM was quadratically influenced by the urea levels, estimating a maximum value of 8.13\% for the 5.11\% level of urea The ammonification with urea altered the bromatological composition of the oats hay improving its nutritional value.
Duckweed is potentially an ideal succinic acid (SA) feedstock due to its high proportion of starch and low lignin content. Pretreatment methods, substrate content and nitrogen source were investigated to enhance the bioconversion of duckweed to SA and to reduce the costs of production. Results showed that acid hydrolysis was an effective pretreatment method because of its high SA yield. The optimum substrate concentration was 140 g/L. The optimum substrate concentration was 140 g/L. Corn steep liquor powder could be considered a feasible and inexpensive alternative to yeast extract as a nitrogen source. Approximately 57.85 g/L of SA was produced when batch fermentation was conducted in a 1.3 L stirred bioreactor. Therefore, inexpensive duckweed can be a promising feedstock for the economical and efficient production of SA through fermentation by Actinobacillus succinogenes GXAS137. (C) 2016 Published by Elsevier Ltd.
In a 5-L fermentor (NBS-MF 105), Saccharomyces cerevisiae W303-181 (1.0 g dry matter/L) was inoculated into 3.0 L of liquid medium containing glucose (10 or 20 g/L), yeast nitrogen base (YNB, 3.7 or 7.4 g/L), L-histidine (0.02 g/L), L-tryptophan (0.02 g/L), uracil (0.02 g/L), and adenine (0.02 g/L). The culture was carried out batchwise for 12 or 24 h at 30 degrees C, pH 4.6 or 5.7, aeration of 0, 0.8, 1.7 or 2.2 vvm, and agitation of 400 rpm. The highest G6PDH productivity (10.5 U/L center dot h) and specific activity (320 U/mg of protein) occurred at aeration of 2.2 vvm, pH 5.7, 10 g/L of glucose, and 3.7 g/L of YNB. The G6PDH specific activity attained was comparable with those of commercial preparations, which are between 50 and 600 U/mg of protein.
The biological production of succinic acid has attracted a great deal of attention due to the depletion of fossil fuels and concerns regarding environmental issues. As a natural producer of succinic acid, Actinobacillus succinogenes is one of the most promising candidates owning to its high production capability, wide carbon utilization spectrum, and robustness to environmental factors. This review details current achievements attempting to improve the efficiency of succinic acid production, not only in terms of raw materials and metabolic engineering strategies but also in terms of process optimization, such as work on neutralizing agents, redox potential, and the supply of CO2. Strategies to reduce the accumulation of byproduct accumulation and to improve succinic acid synthesis are discussed. (c) 2019 Society of Chemical Industry and John Wiley \& Sons, Ltd.
The effect of medium-term (5 years) application of organic and inorganic sources of nutrients (as mineral or inorganic fertilizers) on soil organic carbon (SOC), SOC stock, carbon (C) build-up rate, microbial and enzyme activities in flooded rice soils was tested in west coast of India. Compared to the application of vermicompost, glyricidia (Glyricidia maculate) (fresh) and eupatorium (Chromolaena adenophorum) (fresh) and dhaincha (Sesbania rostrata) (fresh), the application of farmyard manure (FYM) and combined application of paddy straw (dry) and water hyacinth (PsWh) (fresh) improved the SOC content significantly (p < 0.05). The lowest (p < 0.05) SOC content (0.81\%) was observed in untreated control. The highest (p < 0.05) SOC stock (23.7 Mg C ha(-1)) was observed in FYM-treated plots followed by recommended dose of mineral fertilizer (RDF) (23.2 Mg C ha(-1)) and it was lowest (16.5 Mg C ha(-1)) in untreated control. Soil microbial biomass carbon (C-mb) (246 mu g g(-1) soil) and C-mb/SOC (1.92\%) were highest (p < 0.05) in FYM-treated plot. The highest (p < 0.05) value of metabolic quotient (qCO(2)) was recorded under RDF (19.7 mu g CO2-C g(-1) C-mb h(-1)) and untreated control (19.6 mu g CO2-C g(-1) C-mb h(-1)). Application of organic and inorganic sources of nutrients impacted soil enzyme activities significantly (p < 0.05) with FYM causing highest dehydrogenase (20.5 mu g TPF g(-1) day(-1)), phosphatase (659 mu g PNP g(-1) h(-1)) and urease (0.29 mu g urea g(-1) h(-1)) activities. Application of organic source of nutrients especially FYM improved the microbial and enzyme activities in flooded and transplanted rice soils. Although the grain yield was higher with the application of RDF, but the use of FYM as an organic agricultural practice is more useful when efforts are intended to conserve more SOC and improved microbial activity.
Bamboo residue was treated with an active oxygen (O-2) and solid alkali (MgO) (CAOSA) process, which was developed recently by the authors owing to its environmentally friendly and high-efficiency characteristics. During the cooking process, 93.0\% of lignin and 62.1\% of hemicellulose were removed from the raw material, which resulted in a cellulose-rich pulp. This indicated that this cooking process is efficient to fractionate the bamboo residue into cellulose, hemicellulose, and lignin as a pretreatment for biomass conversion. The structural features of the hemicellulose from the pretreated bamboo residue were analyzed for comparison with that of the raw materials. The molecular structure of the hemicellulose fractions obtained from both the raw bamboo and pulp consisted of a (1 -> 4)-beta-D-Xylp backbone substituted with alpha-L-Araf and 4-O-methyl-alpha-D-glucuronic acid. The hemicellulose with more side chains tended to be more easily removed from the bamboo cell wall during the CAOSA process. Furthermore, the fractions of hemicellulose exhibited much lower thermal stabilities after the cooking process than the raw material.
This work aims the study of decomposition kinetics of guarana seed residue using thermogravimetric analyzer under synthetic air atmosphere applying heating rates of 5, 10, and 15 degrees C/min, from room temperature to 900 degrees C. Three thermal decomposition stages were identified: dehydration (25.1-160 degrees C), oxidative pyrolysis (240-370 degrees C), and combustion (350-650 degrees C). The activation energies, reaction model, and pre-exponential factor were determined through four isoconversional methods, master plots, and linearization of the conversion rate equation, respectively. A scheme of two-consecutive reactions was applied validating the kinetic parameters of first-order reaction and two-dimensional diffusion models for the oxidative pyrolysis stage (149.57 kJ/mol, 6.97 x 10(10) 1/s) and for combustion stage (77.98 kJ/mol, 98.61 1/s), respectively. The comparison between theoretical and experimental conversion and conversion rate showed good agreement with average deviation lower than 2\%, indicating that these results could be used for modeling of guarana seed residue. (C) 2016 Elsevier Ltd. All rights reserved.
This study evaluated the effects of three chemical pretreatments of biomass sorghum (BS): dilute alkaline (PTA1 and PTA2), dilute acid (PTB1 and PTB2) and alkaline hydrogen peroxide (PTC1 and PTC2) in the enzymatic hydrolysis and ethanol production. Among the six investigated conditions, the pretreatment with 7.36\% H2O2 (PTC2) was the most efficient in the lignin removal and preservation of the polysaccharide fraction. After the enzymatic hydrolysis, increases in the glucose and xylose concentrations were observed in the pretreated BS hydrolysates, mainly in PTB1 and PTC1. All the hydrolysates obtained low concentrations of inhibitors. In the alcoholic fermentations with Pichia stiptis, the greatest ethanol yield was obtained in PTB1 hydrolysate (3.84 g L-1), corresponding to 16.15\% of yield. The highest ethanol yield in PTB1 hydrolysate can be justified by the maximum concentration of xylose obtained in this hydrolysate, demonstrating the potential of P. stiptis in the fermentation of pentose to ethanol. The results indicated that biomass sorghum is an alternative lignocellulose source with potential for the production of second generation ethanol, opening up prospects for additional studies.
Acid hydrolysis at high temperature is a technique to pretreat and produce monomeric sugars from lignocelluloses; however, its main disadvantage is the production of inhibitory aldehydes. In this paper, reducing sugars production was studied by acid hydrolysis of corn stover employing 2.2 M hydrochloric acid solution and low temperature range (60 - 80 degrees C). Experimental data were great fitted to different kinetic models, thermodynamic parameters were calculated from first order, Saeman and Saeman biphasic kinetic models, rate constants showed similar values between each other demonstrating that corn stover hydrolysis is an endothermic and non-spontaneous process capable to produce thermodynamically stable products. FTIR and SEM analyses showed the breaking of lignocellulosic matrix and the depolymerization of polysaccharides after acid treatment. The proposed operational conditions were adequate to produce reducing sugars avoiding their decomposition into inhibitory aldehydes.
Clostridium thermocellum 27405 is a potential consolidated bioprocessing (CBP) strain due to the efficient lignocellulose degradation ability. Here, the spent mushroom substrate (SMS), a lignocellulosic byproduct of agriculture, was used as a substrate for hydrogen production by C. thermocellum. SMS showed a good performance for hydrogen production and the hydrogen production was significantly enhanced by C. thermocellum supplemented with beta-glucosidases, with the highest production reaching 56.0 mM, an increase of 37\%. Additionally, beta-glucosidase and Triton X-100 had a synergistic effect on biological saccharification, resulted in an accumulation of 5.06 g/L reducing sugars, an increase of 28\%. However, fusion beta-glucosidase showed no improvement on hydrogen production and biological saccharification. The present study demonstrates the different influences of beta-glucosidase and fusion beta-glucosidase on hydrogen production and biological saccharification in CBP system and provides valuable information on the biodegradation of SMS using C. thermocellum. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Maize stover was ozonolyzed to improve the enzymatic digestibility. The interactive effect of sample particle size and moisture content on ozonolysis was studied. After ozonolysis, both lignin and xylan decreased while cellulose was only slightly affected in all experiments. It was also found that the smaller particle size is better for ozonolysis. The similar water activity of the different optimum moisture contents for ozonolysis reveals that the free and bound water ratio is a key factor of ozonolysis. The best result of ozonolysis was obtained at the mesh of -300 and the moisture of 60\%, where up to 75\% lignin was removed. The glucose yield after enzymatic hydrolysis increased from 18.5\% to 80\%. Water washing had low impact on glucose yield (less than 10\% increases), but significantly reduced xylose yield (up to 42\% decreases). The result indicates that ozonolysis leads to xylan solubilization. (C) 2015 Elsevier Ltd. All rights reserved.
A modified alkali pretreatment (MAP) process was established in both lab-scale and pilot-scale, based on the on-line production and utilization of lignosulfonate for improving enzymatic saccharification of corn stover. Sodium lignosulfonate (SLS) produced by directly sulfonating lignin in spent liquor separated from alkali pretreatment was reused in the next cycle of alkali pretreatment. The results showed that, by using 11 wt\% NaOH, 2 wt\% SLS and 0.1 wt\% anthraquinone (AQ) in MAP, delignification rate and final total sugar yields could reach about 78\% and 80\% respectively, which were about 6\% and 9\% higher compared to the blank conventional NaOH pretreatment under the same conditions. In addition, sulfonation degree of SLS had linearly impact on the final total sugar yields. (C) 2015 Elsevier B.V. All rights reserved.
Alkali thermal pretreatment can effectively destroy the compact three-dimensional aggregated structure of lignocellulose, and further promote the production of high value-added chemicals. Cellulose is an important component of lignocellulose, and in this study the mechanism of cellulose hydrolysis in alkali thermal pre-treatment was studied by density functional theory. The hydrolysis was divided into two steps, firstly the hy-droxide ion captured a proton from the hydroxyl of which had most positive potential value of 1.23 eV. Subsequently, the glycosidic bond was cleaved to form a new C-O bond, and the hydroxide ion attacked the intermediate forming a glucose residue by a new covalent. The amount of electron transfer of the two steps were natural orbitals for chemical valence eigenvalue 0.31 and 0.34, and the corresponding energy barriers were 147.11 and 101.17 kJ/mol at 298.15 K, respectively. With the increase of pretreatment temperature from 298.15 to 413.15 K, the enthalpy and Gibbs free energy change of cellobiose hydrolysis decreased by 2.97 and 2.34 kJ/ mol and the thermodynamic feasibility and reaction rate increased. This study will providing an important guidance for the process control, reactor design and performance enhancement of lignocellulose pretreatment.
A cost-effective strategy for superfine bacterial nanocellulose (BNC) production was successfully developed by the low-nutrient adaptive mutation. Two adapted strains, RC30-15 and RC37-23 were obtained from revertant strain R37-9 of Komagataeibacter oboediens MSKU 3 by a repetitive static cultivation at 30 degrees C and 37 degrees C, respectively. The repetitive cultivation was carried out in coconut water (CW) containing 1\% acetic acid and 2\% ethanol (CW1A2E), CW1A2E containing 0.5\% sucrose (CW1A2E0.5S) and CW1A2E0.5S containing 0.5\% ammonium sulfate (CW1A2E0.5S0.5N) for 30 passages (210 days). Strain R37-9 produced relatively low amount of superfine BNC of 0.71, 0.88 and 0.82 g/L dry weight after 7 days static cultivation at 37 degrees C in CW1A2E, CW1A2E0.5S and CW1A2E0.5S0.5N, respectively. Two adapted strains exhibited higher BNC producing ability in coconut water than strain R37-9. Strains RC30-15 and RC37-23 produced the highest BNC yields of 3.63 and 8.22 g/L dry weight in CW1A2E0.5S and CW1A2E0.5S0.5N under static cultivation at 30 degrees C and 37 degrees C, respectively. SEM images of the nanofibrils produced from strain RC37-23 showed the finer nanocellulose fibrils and narrower range (24 +/- 0.47-34 +/- 0.81 nm) of fibril width compared with other strains. Furthermore, the density, moisture content and porosity of nanocellulose fibrils produced from strain RC37-23 in CW1A2E0.5S0.5N medium at 37 degrees C exhibited the highest density (0.86 +/- 0.02 g/cm(3)) and moisture content (12.51 +/- 1.87 \%). BNC from strain RC37-23 grown in CW1A2E0.5S0.5N medium at 37 degrees C also possessed the lowest porosity (42.59 +/- 1.70\%). It could be concluded that low-nutrient adapted strain at 37 degrees C, strain RC37-23, produced not only the highest amount of BNC but also the better physicochemical properties of nanocellulose fibrils.
Acid hydrolysis was performed to produce reducing sugars from pineapple crown (PC), corn cob (CC), and rose stem (RS); the holocellulose contents of PC, CC, and RS were 69.36\%, 70.17\%, and 63.89\%, respectively. The highest production of reducing sugars was obtained at 150 degrees C and 1.5 M sulfuric acid (H2SO4) for PC (46.04 g/100 g) and 2.0 M (H2SO4) (41.61 and 15.96 g/100g respectively) for CC and RS with a reaction time of 150 min. The Saeman equation adequately described the hydrolysis kinetics. The production of reduced sugars was the predominant reaction (k(1)> k(2), k(r)> 1) instead of decomposition for PC and CC, and that of RS was dominated by the decomposition. The E-a obtained from the Arrhenius equation showed that PC and CC (3.676 kJ/mol mean value from all concentrations used) are more easily hydrolyzable materials than RS (E-a=10.95 kJ/mol mean value). The trends in the thermodynamic parameters, Delta H, and Delta G, showed that hydrolysis is an endothermic and non-spontaneous process. The temperature had a greater influence on the production and decomposition of reducing sugars than did the concentration of H2SO4 for PC and CC.
A solid amine adsorbent based on sisal fiber was prepared by grafting copolymerization, in which amine was covalently bound onto sisal fiber. In the absence of moisture, the adsorption capacity of the triethylenetetramine-aminated solid amine fiber (SF-AM-TETA) for CO2 could be 0.75 mmol g(-1) through physical adsorption of pores inherited from the bio-texture of sisal fibers. The adsorption capacity of SF-AM-TETA was greatly promoted by the presence of moisture, which could reach 4.20 mmol g(-1) at room temperature. After 7 adsorption-desorption cycles, the regenerated fiber showed a adsorption capacity of 3.92 mmol g(-1), 93\% regeneration efficiency, which confirmed that SF-AM-TETA was capable of keeping its stability and CO2 adsorption capacity even after numbers of regeneration cycles. Furthermore, in order to better interpret the adsorption behavior and adsorption kinetics of the solid amine fiber SF-AM-TETA, two models were applied to fit CO2 adsorption experimental data at different temperatures. The results indicated that the solid amine fiber tended to absorb CO2 by a physical process in the absence of moisture while the chemical absorption was the main process occurring in the presence of moisture.
Utilization of the huge quantity of sawdust wastes is urgent. In this study, SPORL, dilute acid pretreatment (DA), formic acid pretreatment (FA), ethanol pretreatment (EtOH/H2O), and sulfuric acid catalyzed ethanol pretreatment (EtOH/H2O/H2SO4), on improving enzymatic hydrolysis of mixed sawdust wastes were comprehensively compared. EtOH/H2O/H(2)SO(4 )was the most effective pretreatment in lignin removal from sawdust fiber cell wall, while FA was much more effective in hemicellulose removal. After the pretreatments, the crystallinity of cellulose increased because of the removal of amorphous hemicellulose and lignin. Moreover, the fiber surface became coarse and porous, especially after EtOH/H2O/H2SO4, the structure was destroyed into fragments, which enhanced the cellulase accessibility of cellulose. Therefore, the glucose yield of EtOH/H2O/H2SO4 pretreated substrate was highest among these five pretreatments, achieved at 91.4\% with a cellulase loading of only 10 FPU/g glucan.
In the present work the products and characteristics of bio-yields obtained from pyrolysis of different types of walnut shells (WS) by using a fixed bed pyrolyzer. The different walnut shells considered are paper (PSW), thin (TSW), medium (MSW) and hard (HSW) shelled walnut. The biomass samples were pyrolyzed at various temperatures, particle sizes, heating and sweep gas flow rates. The results revealed that the maximum bio-oil 44.7, biochar 37.6 and gas 40.4 wt\% yields have been obtained for HSW, MSW and HSW at a pyrolysis temperature of 550, 375 and 750 degrees C respectively at heating rate 0.33 K/sec, particle size 0.5-1.5 mm with swept gas flow rate 1.6 x 10(-6) m(3)/s. The higher heating value (HHV) of bio-oil obtained from different walnut shells are ranged from 26 to 27.3 MJ/kg. Comprehensive physiochemical characteristics such as density, viscosity, flash point, pour point and water content of bio-oils have been obtained. Chemical composition analysis of bio-oils revealed that the pyrolytic bio-oil composition is predominated by oxygenated compounds such as carbonyl, methoxy, phenols and carboxyl groups determined by GC-MS, FTIR, H-1 NMR and C-13 NMR. The pyrolysis gas mainly contained CH4 CO, H-2, CO2, and light hydrocarbons. Based on these results and structural analysis of the bio-oil, it can be concluded that the bio-oil obtained from WS may be used as a feedstock for furnaces, as a fuel, as a lubricant after modifications and value-added products via pyrolysis.
Surface-wave discharges in argon at atmospheric pressure were experimentally studied by optical emission spectroscopy (OES) and mass spectrometry (MS). OES was employed to determine the rotational temperature using the ultraviolet OH band, Q(1) branch and found to be between 450 and 970 K. The electron density (5 x 10(13) cm(-3) <= n(e) <= 7 x 10(14) cm(-3)) was estimated using the H-beta line profile, and produced by dissociation of the water present as an impurity in the Ar gas. The electron temperature (0.63 eV <= T-e <= 1.3 eV) was estimated using a collisional-radiative (CR) model that takes the input measured intensities of four emission lines originating from 2p states including 2p(2), 2p(4), 2p(6), and 2p(10). The density of the metastable state Ar(1s(5)) (2.0 x 10(11) cm(-3) <= Ar(1s(5)) <= 4.2 x 10(12) cm(-3)) was estimated by means of OES using the self-absorbing method. Positive and negative ions were probed along the plasma column using MS. A theoretical model based on the solution of the homogeneous electron Boltzmann equation, considering inelastic and superelastic collisions with the Ar(1s) states and electron-electron collisions, coupled with a system of rate balance equations describing the creation and destruction of the most important heavy particles, is proposed. The experimental results are compared with theoretical ones obtained from a self-consistent model of these discharges, providing physical insight into the basic mechanisms and phenomena ruling the discharges.
Three organosolv and three alkaline hemicellulosic fractions were prepared from lignocellulosic biomass of the fast-growing shrub Tamarix austromongolica (Tamarix Linn.). Sugar analysis revealed that the organosolv-soluble fractions contained a higher content of glucose (33.7-6.5\%) and arabinose (14.8-5.6\%), and a lower content of xylose (62.2-54.8\%) than the hemicellulosic fractions isolated with aqueous alkali solutions. A relatively high concentration of alkali resulted in a decreasing trend of the xylose/4-O-methyl-D-glucuronic acid ratio in the alkali-soluble fractions. The results of NMR analysis supported a major substituted structure based on a linear polymer of beta-(1 -> 4)-linked D-xylopyranosyl residues, having ramifications of alpha-L-arabinofuranose and 4-O-methyl-D-glucuronic acid residues monosubstituted at O-3 and O-2, respectively. Thermogravimetric analysis revealed that one step of major mass loss occurred between 200-400 degrees C, as hemicelluloses devolatilized with total volatile yield of about 55\%. It was found that organosolv-soluble fractions are more highly ramified, and showed a higher thermal stability than the alkali-soluble fractions. (C) 2011 Elsevier Ltd. All rights reserved.
Accurate temperature tracking for fast heating/cooling and regulation during the batch pretreatment of lignocellulosic biomass (LCB) is required to guarantee high product yield and quality repeatability. However, yield discrepancies are frequently found in the pretreatment literature in which temperature trajectory or heating sources details are seldom reported. Innacurate temperature control may be one of the reasons for these discrepancies. This paper proposes a tracking-regulation-tracking temperature control system for batch pretreatments of LCB heated by an electrical jacket heater. The accuracy of the control system in tracking the temperature set point trajectory is measured with the weighted integral of the absolute error (SIC). The controlled process performance was measured with the percentage difference between the experimental lignin recovery percentage and the value calculated with a steady-state mathematical model using the average temperature of the isothermal reaction period. The system was tested in an ethyl lactate-based 190 ?, 1 L batch organosolv pretreatment with a maximum heating rate of 8.6 ?/ min and a mean cooling rate of -2.4 ?/min. The process performance was 2.8\% for an (SIC) of 1044 ?/ min thus confirming the efficacy of the proposed control system.
The potential of clover (Trifolium repens) and ryegrass (Lolium perenne) mixtures as raw materials for ethanol production was investigated. Wet oxidation, at 175, 185 or 195 degrees C during 10 min at two different oxygen pressures and with either addition or no addition of sodium carbonate, was evaluated as pretreatment method for clover-ryegrass mixtures. The enzymatic hydrolysis of cellulose was significantly improved after pretreatment. The highest conversion efficiency, 93.6\%, was achieved for the sample pretreated at 195 degrees C, 10 min, 1.2 MPa and no addition of Na2CO3. For that sample, the overall glucose yield after pretreatment and hydrolysis was 75.5\%. No inhibition of cellulose enzymatic conversion by the filtrates was observed. The simultaneous saccharification and fermentation of the pretreated material yielded cellulose conversions of 87.5 and 86.6\%, respectively, with Sacchar omyces cerevisiae and the filamentous fungus Mucor indicus, and revealed that no addition of nutrients is needed for the fermentation of clover-ryegrass hydrolysates. (C) 2008 Elsevier Ltd. All rights reserved.
With the aim of separating cellulose-rich material from river red gum, it was pre-treated with three ionic liquids (ILs), i.e. 1-butyl-3-methylimidazolium chloride ({[
A semi-dry oven method, being environmental friendly and simple process with the absence of organic solvents, was applied to prepare cationic xylan by quaternization of xylan with 3-chloro-2-hydroxypropyltrimethylammoniumchloride (CHMAC) using sodium hydroxide as a catalyst in this study. The parameters including reaction time (1-9 h), reaction temperature (50-80 degrees C), the molar ratio of CHMAC to xylan (0.8-3.0), and the molar ratio of NaOH/CHMAC (0.8-1.6) were optimized and the extent of quaternization was measured by degree of substitution (DS). The appropriate DS between 0.10 and 0.41 was achieved by varying the reaction parameters. Compared to the heterogeneous system (ethanol/water), the relatively higher DS could be obtained by the semi-dry oven method. Moreover, results show that a substantial degradation of the xylan polymers occurred during the modification. Therefore, this study provides feasibility of industrial production of cationic xylan.
Fractionation of flax shives into major biopolymer constituents, such as cellulose, hemicelluloses, and lignin, was carried out with pressurized aqueous ethanol in a pressurized low-polarity water extractor. The effect of processing parameters such as temperature, ethanol concentration, flow rate, sample size and solvent/feed ratio on the simultaneous extraction of hemicelluloses and lignin was determined. More than 80\% of total hemicelluloses and similar to 78\% of total lignin were removed simultaneously in a single step under the following conditions: 180 degrees C, 30\% (v/v) ethanol concentration, 3 mL/min flow rate, and 45 mL/g solvent/feed ratio. Under these extraction conditions, cellulose degradation was negligible. Further, the separation of lignin from hemicelluloses was carried out using two simple alternative methodologies based on precipitation. Since no acidic or alkali catalysts were used, the degradation of biopolymers was negligible and the oligomer/monomer ratio of sugars was 825:1. Characterization of fractionated biopolymers was carried out with scanning electron microscopy and a Fourier-transform infrared spectrometer (FT-IR). FT-IR spectra of isolated lignin and hemicelluloses showed that both polymers were comparable to commercially available products. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.
Deffated rice bran has potential to processing into ethanol due to its lignocellulosic composition and agricultural productivity. The composition of the pretreated deffated rice bran with Deep Eutectic Solvent was investigated aiming the production of sugars and bioproducts using subcritical water hydrolysis. Changes in the deffated rice bran composition at different pretreatment times and mixtures of deep eutectic solvent were evaluated by the derivative of thermogravimetric analysis. The pretreated deffated rice bran presented an enrichment in the content of hemicelluloses (281.0\%) and delignification (59.3 \%). Under the same condition of subcritical water hydrolysis (230 degrees C/R-100) the yield of fermentable sugars increased 2.20 times in the same study time interval (20 min) when comparing pretreated and untreated deffated rice bran.
Bio-oil produced from lignocellulosic biomass (LCB) offers significant advantages as a sustainable energy source for future generations. However, its low-quality demands better approaches to solve problems such as low calorific value, low stability, and high oxygen content. This study investigates the feasibility of producing hydrocarbon-rich oil through supercritical ethanolysis (scEtOH) co-liquefaction of cotton gin trash (CGT) and plastic waste. The scEtOH co-liquefaction studies were carried out using various mixing ratios of cotton gin trash (CGT) and low-density polyethylene (LDPE) at a temperature range of (240-340 degrees C), for reaction time (0-3 h) without catalysts. Positive effects on oil yield and higher hydrocarbon content were observed at 320 degrees C for 2 h with CGT/LDPE ratio of 1:2 under the optimised reaction conditions. Further co-liquefaction studies on the CGT/ LDPE feedstock ratios (2:1, 1:1, 1:2) at 320 degrees C and 2 h showed positive synergistic effects on oil yield and the hydrocarbon content in the oil increased from 3.7 wt\% to 17.2 wt\% when LDPE proportion was increased from 33.33\% to 66.66\%. Maximum higher heating values (HHV) of 31.5 MJ/kg for oil and 42.5 MJ/kg for solid products were obtained at CGT/LDPE ratio of 1:2. Additionally, the co-liquefaction of CGT and LDPE improved the carbon content in solid products from 50.9 wt\% to 85.4 wt\% which can be used as a sustainable carbon resource. Our results demonstrate that the co-processing of LCB and plastic wastes through scEtOH coliquefaction is a sustainable approach to improve fuel quality, facilitate plastic recycling, and compensate for decreased availability of biomass due to seasonal variations.
The oil spillage and maritime pollution due to spilled oil have been affecting human life and the environment in the long term seriously. The methods and techniques presently used to recover oil spills must be carefully considered to avoid creating unexpected secondary pollution as well as time-consuming. Therefore, the application methods for spilled oil recovery should be available, fast responsive, economical, highly absorbing, and nontoxic for the environment. The use of absorbents originated from natural organic byproducts is considered a suitable method for treating spilled oil because of their outstanding physical properties for the sustainable strategies of environmental protection. In this review paper, the factors affecting the oil absorption capacity of the raw cellulose-originated natural organic absorbents such as the nature of absorbent and properties of spilled oil are thoroughly analyzed. Moreover, the suggestion of applications of raw cellulose-absorbents in combination with other methods was also mentioned in detail. In general, the utilization of raw cellulose-based absorbents could absorb the spilled oil with a maximum yield of around 70\%, and raw cellulose-based absorbents could be only suitable for near-shore oil spills. In future work, advanced absorbents based on cellulose should be further investigated and developed to increase the efficiency of spilled oil recovery aiming to satisfy the challenges relating to the disaster of oil spills in maritime operation.
Liquid hot water pretreatment is considered to be a promising method for increasing biomass digestibility due to the moderate operational conditions without chemical additions. A necessary step towards the scalability of this pretreatment process is performing pilot plant trials. Upscaling was evaluated with a scaling factor of 500, by using 50 mL in the laboratory and 25 L in a pilot plant batch reactor. Pretreatment times were varied from 30 to 240 min, and temperatures used were 180-188 degrees C, while applying similar heating profiles at both scales. The initial mass fraction of poplar wood chips ranged from 10\% to 16\%. Liquid hot water pretreatment at laboratory and pilot scale led to analogous results. The acetic acid analysis of the liquid and solid fractions obtained after pretreatment indicated that complete deacetylation of poplar biomass can be achieved.
Currently the watercolor used in painting on paper has been confronted with many problems such as deterioration, fragility and fading to light. This study evaluates the potentials of cellulose nanocrystals (CNCs) in improving painting efficiency of watercolor paint. The paint was mixed with cellulose nanocrystals (CNCs) at different concentrations (1, 3, 5 and 7 wt.\%). The CNCs-based mixture was painted on paper, and the presence of CNCs in the painting was confirmed by energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) analysis. Scanning electron microscopy (SEM) analysis demonstrated better smoothness of watercolor paint mixed with CNCs on paper than painting without CNCs. Mechanical test showed the CNCs concentrations of 3 and 5\% were significantly higher, in terms of tensile strength and Young's modulus. There was an improvement in color fastness to light from ``noticeable fading{''
Background and Aims. The complex structure of the lignocelluloses is the main obstacle in the conversion of lignocellulosic biomass into valuable products. Ionic liquids provide the opportunities for their efficient pretreatment for biomass. Therefore, in this work, pretreatment of corn stalk was carried out in ultrasonic-assisted ionic liquid including 1-butyl-3-methylimidazolium chloride {[
In this work the application of different hemicellulosic derivatives including different degrees of substitution (DS) cationic hemicelluloses and carboxymethyl hemicelluloses in sulfate kraft pulp were investigated in detail. It was found that cationic hemicelluloses and carboxymethyl hemicelluloses could improve the physical properties of hand sheets, while the cooperation of cationic hemicelluloses and carboxymethyl hemicelluloses could enhance sharply the physical properties of hand sheets. When the dosages of cationic hemicelluloses with DS of 0.37 and carboxymethyl hemicelluloses with DS of 0.35 were 1.0\% and 1.0\% (based on dry pulp weight), respectively, the physical properties of hand sheets was significantly improved. breaking lengthen and tear index of hand sheets increased by 21.1\% and 54.6\% compared with the control hand sheets without any additives added. The fiber intertexture of the hand sheets was observed by SEM. The results indicated that hemicelluloses could be used as the source for the production of wet-end additives in papermaking, which might represent an important strategy for sustainable use of the agricultural residue. (C) 2008 Elsevier Ltd. All rights reserved.
The influence of torrefaction pretreatment on the properties of briquettes made from the blends of sawdust (SD) and cassava peel (CP) was studied. These feedstocks were combined at mixing ratios of 90/10, 70/30, 50/50, 30/70 and 10/90 for untreated and torrefied conditions. The physical and combustion properties were determined using standard methods. Results obtained at all mixing ratios show that the fixed carbon, volatile ignitability, and calorific value increase with the increase in the torrefaction temperature. Further results show that the physical and mechanical properties yield better result through water preconditioning. This work established that high quality briquettes with improved strength and caloric value could be produced from discarded SD and torrefied CP.
The mushroom Agaricus brasiliensis is usually grown in potato-based or compost media. The objective of this work was to evaluate the in vitro development of the strain ABL 97/11 of A. brasiliensis grown in culture medium supplemented with brans of maize; wheat, rice and soybean, in different concentrations. Cultivation was performed under constant temperature of 28 degrees C. Diameter of the colony was evaluated daily and after six days of cultivation, mycelial mass was obtained. The addition of soybean or rice brans did not favor the development in vitro of A. brasiliensis. The largest averages of mycelial mass and growth rate are obtained in medium containing 20\% of wheat bran. The medium containing 10\% of maize corn presents the highest growth rate among the different media under the same bran concentration.
In this study, Trichoderma harzianum LZ117 was obtained during screening of cellulolytic enzyme producers from samples collected in Tibet. T. harzianum LZ117 exhibits dramatically earlier enzyme induction (48 h) and shorter fermentation time (5 days) during cellulase production when compared with the widely studied strain T. reesei QM9414. Strain LZ117 showed 61\% of the maximum cellulase activity at 48 h, whereas only 17\% of the maximum cellulase activity was detected in QM9414 at the same culture time. Early induction and rapid production of cellulase were also observed in LZ117 when compared with two other T. harzianum strains. Significantly higher glucose yield was obtained using crude enzyme from strain LZ117 from pretreated corn stover and Jerusalem artichoke stalks when compared with that of T. harzianum reference strain K223452. These results indicate that strain LZ117 is a promising cellulase producer for bioconversion of lignocellulosic biomass.
Cellulose is a polysaccharide composed of D-glucopyranose linked by 1,4 beta-glycoside bond with three hydroxyl groups. These hydroxyl groups in cellulose have an important role in the compactness of crystalline structure and in determining the physical properties of cellulose. Cellulose in nanometers size range from 10 nm to 350 nm is known as nano cellulose, which has a variety of applications due to the unique properties such as low density, biodegradable, and good mechanical properties. In the present study, we present the isolation of the nano cellulose from flaxseed hull for the first time. The isolated nano cellulose was characterized by techniques such as UV- Vis, FT-IR, BET, XRD SEM, and TEM. The nano cellulose obtained was found to be crystalline in nature with a crystallinity index of 46\% and the surface area of 5 cm(2)/g with excellent thermal stability. (C) 2020 The Author(s). Published by Elsevier B.V. on behalf of King Saud University.
The efficiency of organic acid treatment in the conversion of lignocellulosic biomass fractions has been widely recognized. In this study, a novel green pyruvic acid (PA) treatment is proposed. The higher separation efficiency of eucalyptus hemicellulose was obtained at 4.0\% PA and 150 degrees C. The hemicellulose separation yield was increased from 71.71 to 88.09\% compared to glycolic acid (GA) treatment. In addition, the treatment time was significantly reduced from 180 to 40 min. The proportion of cellulose in the solid increased after PA treatment. However, the accompanying separation of lignin was not effectively controlled. Fortunately, a six-membered ring structure was formed on the diol structure of the lignin \& beta;-O-4 side chain. Fewer lignin-condensed structures were observed. High-value lignin rich in phenol hydroxyl groups were obtained. It provides a green path for the simultaneous achievement of efficient hemicellulose separation and inhibition of lignin repolymerization using organic acid treatment.
Porous celluloses (PCs) were successfully prepared by a simple process of freezing the cellulose solution in ionic liquid, followed by solvent exchange and drying at normal temperature instead of the supercritical drying. PCs were composed of cellulose sheets of low crystallinity, as evidenced by SEM, XRD, TGA and FTIR, oriented into unidirectional structures when the cellulose concentration was low (1 \%). When the cellulose concentration was high (4 \%) the structure was twisted and randomly oriented. PCs had low apparent densities of 44-88 mg/cm(3) and oil adsorption capacities ranging from 9.70 to 22.40 g/g (oil/PC) due to the ultralight porous structures. Oxidation of sodium periodate introduced dialdehyde groups into the porous structure. After the same reaction time, the aldehyde content of PC was much higher than the untreated cellulose counterpart. The resultant dialdehyde modified-PC had better urea adsorption than modified-viscose fiber. The high reactivity of PCs was related to the low crystallinity and porous structure.
The production of cow manure far exceeds the quantity that can be utilized in primary applications such as fertilizer or for the generation of biogas. As a result, alternative value-added applications are being investigated. The purpose of this study is to evaluate the production of lactic acid, using cow manure as the raw material. The methodology involved the implementation of thermochemical pretreatment for the cow manure, followed by simultaneous saccharification and fermentation for lactic acid production. Response surface methodology based on a central composite design was employed to analyze the simultaneous saccharification and fermentation process. The factorial design of the experiments was carried out with three factors, cow manure concentration, temperature, and enzyme concentration, with 80 g \& BULL;L-1, 50 \& DEG;C, and 212.5 IU/gCM(Dry Matter) as central point values, respectively. Following the addition of Bacillus coagulans DSM2314 inoculum to enzymatically hydrolyzed cow manure at pH 5.0, after a 24 h period the concentration of lactic acid was recorded at 13.65 g \& BULL;L-1, with a conversion efficiency of 33.1\%. Studies were conducted until 48 h to analyze time impact. Characterization studies for native cow manure and that pretreated using acid reagent were conducted. Sugar content and by-product formation were analyzed, resulting in 23.24 g \& BULL;L-1 of sugar remaining as the maximum after fermentation, while low values of furfural (1.04 g \& BULL;L-1), 5-hydroxymethylfurfural (1.35 g \& BULL;L-1), and acetic acid (1.45 g \& BULL;L-1) were found. Optimal conditions were calculated at 24 and 48 h with R software, obtaining the lactic acid, with yields of 13.4 g \& BULL;L-1, 36.28\% (for 24 h) and 15.27 g \& BULL;L-1, 32.76\% (for 48 h), respectively. Experimental and statistical studies of enzymatic hydrolysis and fermentation stated that cow manure was a feasible substrate for the production of lactic acid.
To improve the utilization of phragmites in biorefineries, the strengthening effect of byproduct-organic acids on the subcritical liquid hot water (SLHW) pretreatment was explored. The byproduct-organic acids were accumulated during the direct recycling of pretreated liquid, which could reduce water consumption. The byproduct-organic acids, including acetic acid and lactic acid, were used to strengthen the SLHW pretreatment of raw phragmites at different temperatures (160-200 degrees C) and times (20-90 min) in the strengthening process. During the SLHW pretreatment, the high yield of C-S sugars was 60.66\% at the severity of 4.85 (200 degrees C, 75 min). However, the maximum C-S sugars yield in the strengthening process was 85.01\% at 180 degrees C, for SO min, and with 2.106 wt \% byproduct-organic acids, which were obtained by the direct recycling of pretreated liquid for 3 times at 160 degrees C and for 30 min. Therefore, the full utilization of byproduct-organic acids could provide another economically feasible way to strengthen the SLHW pretreatment.
In this study, the giant reed (Arundo donax L.) was used as a substrate for bioethanol production. To study and optimize the effect of bioethanol production parameters, including sodium hydroxide (NaOH) concentration (3-9, w/w\%), temperature (60-180 degrees C), and pretreatment duration (30-120 min), on bioethanol concentration, and theoretical bioethanol yield, response surface methodology (RSM) based on the Box-Behnken design (BBD) was used. Alkaline pretreatment with NaOH was done on the substrate and all the samples were subjected to an enzymatic degradation experiment under conditions of loading 30 FPU cellulase/g dry biomass and then converted to bioethanol by Saccharomyces cerevisiae yeast. The results showed significant effects of the variables on bioethanol production, except for the effects of temperature on theoretical bioethanol yield. The optimal conditions for producing bioethanol under alkaline pretreatment conditions are a NaOH concentration of 3.0\%, a temperature of 60 degrees C, and a pretreatment duration of 30 min which identified the optimal conditions of bioethanol concentration (3.19 g/L), and theoretical bioethanol yield (25.62\%). These results contribute to supporting the potential of giant reed biomass as a suitable raw material for bioethanol production.
Isolation of hemicelluloses through alkaline extraction results in formation of salts, which usually necessitates additional salt removal steps. In this study, acetylation of xylans was studied without the removal of potassium acetate (KAc), a commonly produced salt during the alkaline extraction, to find a facile method to alter the hydrophilic characteristics of hemicelluloses. The acetylation reaction was carried out solely with acetic anhydride without any catalysts or solvents added. The weight gain and ATR-FTIR analyses verified the acetylation of xylans in the presence of KAc. A significant decrease in water solubility and moisture uptake was observed upon acetylation in the presence of KAc which is also accompanied by an increase in thermal stability, disclosing an easy, efficient and environmentally friendly method to obtain hydrophobically modified xylans without the use of toxic catalysts and costly salt purification steps.
BACKGROUND The conversion of lignocellulose to sugar is part of the process of lignocellulose biorefining and, therefore, is crucial for effective lignocellulose utilization. RESULTS In this study, alkali and acidic pretreatments were carried out to deconstruct corn stalk (CS) material for efficient subsequent enzymatic saccharification. Most xylan and lignin can be removed from CS material by acid and alkali pretreatments, respectively, as verified by XRD (X-ray diffractometer) and FT-IR (Fourier Transform Infrared Spectroscopy) analyses. Fractal-like kinetics were assessed to analyze the effect of enzyme loading on the glucose and xylose sugar yields from the two pretreated CS materials, with fractal dimension considered as a dominant factor in rate constant decrease. Fractal dimension analysis demonstrated that the alkali pretreated CS was more easily hydrolyzed that the acid pretreated CS. For glucan hydrolysis, the effect of enzyme loading on the rate constant of the alkali pretreated CS was marginally higher than that of the acid pretreated CS. For xylan hydrolysis, enzyme loading was shown to significantly improve the rate constant of the alkali pretreated CS compared to the acid pretreated CS. Furthermore, the developed fractal-like model exhibits high prediction accuracy for sugar yield at high enzyme loadings. CONCLUSION The application of the fractal-like theory was quite successful for studying enzymatic kinetics. (c) 2022 Society of Chemical Industry (SCI).
Due to ever increasing use of polymer composites and rising environmental concerns throughout the world, greater attention is being paid to the incorporation of lingo-cellulosic materials as filler in polymer matrices instead of synthetic materials in the field of aerospace and automobile industry. In this work, polystyrene composites using wheat husk, rice husk and mustard husk as fillers are synthesised using in-situ polymerisation technique. Three different filler loading (5, 10 and 15 \%) and three different filler sizes (250-355 mu, 355-500 mu, 500-710 mu) were utilised for the studying the effect of these compositions on different mechanical properties of the synthesised composites. The results have shown that the filler size 250-355 mu and 5\% loading give the maximum values for tensile strength, flexural strength and hardness for all the three types of fillers. While in case of water absorptivity the lower the size/loading, lesser would be the water absorbed. The SEM analysis is done to study the fractured surface of the specimen.
The complete utilisation of Dried Distillers Grains with Solubles (DDGS) requires effective pretreatment strategies aiming to increase the enzymatic digestibility of cellulose and improve its conversion to fermentable sugars. To this end, the effect of different NaOH concentrations (0-5\%, w/v) and temperature (30-121 degrees C) on the fractionation of DDGS to its main components (cellulose, hemicellulose, proteins) was evaluated. As the NaOH concentration and temperature increased, the total sugar content of the pretreated DDGS solids progressively increased to a maximum of similar to 88\%. At 121 degrees C and 5\% NaOH, the DDGS solid residue consisted primarily of glucose (similar to 53\%), a 5-fold increase compared to the original DDGS, reflecting the presence of cellulose, and to a lesser extent by xylose (similar to 25\%) and arabinose (similar to 10\%) reflecting the presence of hemicellulose. Approximately 83\% of the initial hemicellulose and 79\% of the protein contents were removed into the liquid fraction during alkaline pretreatment. The enzymatic digestibility of the pretreated DDGS solids by the Accellerase (R) 1500 cellulase enzyme was significantly improved, resulting in a 3.6 fold increase in glucose yield compared to untreated DDGS. Mass balance analysis demonstrated that the proposed process scheme recovers the majority of the key DDGS components (cellulose, hemicellulose, proteins) in an efficient manner with relatively low losses, and provides a viable approach for the valorisation of DDGS. (C) 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
The aim of this study was to investigate the effect of oyster shell powder (OSP) and rice husk ash (RHA) on the pyrolysis of rice husk (RH) for bio-oil. The present study focuses on the effect of catalysts on pyrolysis of RH for bio-oil and the quantity of bio-oil produced. The results showed that both OSP and RHA could improve the yield and quality of bio-oil, and the catalytic effect of OSP was better than that of RHA. With the content of the two catalysts increased, the net increase range of bio-oil yield decreased gradually. With 3 wt.\% of OSP or 2 wt.\% of RHA, the yield of bio-oil achieved to 57.06\% and 56.07\% respectively, which increased by 6.03\% and 4.20\% compared to that of single pyrolysis of rice husk. Both OSP and RHA can increase the bio-oil heating value and decrease the acid value. With the presence of 1-5 wt.\% of OSP or RHA in the RH pyrolysis process, the heating value of the bio-oil can be increased by 5.04-10.25\% and 4.32-5.78\%, the acid value of the bio-oil can be decreased by 5.30-13.54\% and 9.81-33.01\%, respectively. OSP was better than RHA on the heating value improvement, while RHA was superior to OSP in decreasing the acid value. The gas chromatography/mass spectrometry (GC-MS) analysis of bio-oil composition indicated that the formation of phenols, acids and ketones compounds were inhibited and alcohols and furan compounds were promoted with the addition of OSP and RHA catalysts. The study made the catalytic pyrolysis process more favorable for the production of high heating value fuel.
Ozonolysis and subsequent wet-disk milling (DM) were carried out on Japanese cedar (Cryptomeria japonica) to improve sugar production by enzymatic saccharification. When the moisture content reached more than 40\%, ozone consumption decreased, resulting in less delignification. Ozone treatment removed mainly lignin, but also small amounts of polysaccharides. The application of DM following the ozone treatment further increased glucose and xylose yields, but had no significant effect on mannose yield, due to the loss of mannan in the ozone-treated product and the lack of mannose-releasing activity in the hemicellulase used. Sugar concentration increased with substrate concentration, when a constant ratio of enzyme to substrate was used. (C) 2012 Elsevier Ltd. All rights reserved.
Asymmetric membranes may be used in a broad range of applications such as reverse osmosis, hemodialysis and separation of organic mixtures. In this paper, asymmetric membranes were produced using cellulose acetate (CA) from biomass: newspaper and mango seed. The degree of substitution of CA was 2.65 +/- 0.07. Different formulations were used to prepare the CA membranes: CA/dichloromethane/water with and without magnesium perchlorate. The asymmetry of the membranes was characterized by scanning electron microscopy (SEM). Membranes produced with magnesium perchlorate presented higher water vapor flux than those produced without this salt. This difference is due to pore formation in the membrane skin when using magnesium perchlorate. Membrane substructure showed to be a determining factor in ion diffusion experiments. The coefficient of ion diffusion for the membrane of cellulose acetate from mango seed was 1.82 x 10(-8) cm(2) s for the membrane of cellulose acetate from newspaper was 7.43 x 10(-8) cm(2) s similar to the value reported in the literature for commercial CA (8.46 x 10(-8) cm(2) s(-1)). (C) 2010 Elsevier Ltd. All rights reserved.
The enzymatic bioconversion of xylose into xylitol by xylose reductase (XR) is an alternative for chemical and microbiological processes. The partial purified XR was obtained by using the following three procedures: an agarose column, a membrane reactor or an Amicon Ultra-15 50K Centrifugal Filter device at yields of 40\%, 7\% and 67\%, respectively.
In the present work water soluble hemicellulosic polysaccharides HPW, 2\% NaOH soluble hemicelluloses HP and HP, and 5\% KOH soluble fractions HP and HP, were classically separated from bamboo (Phyllostachys pubescens Mazel) aged one year. In addition to sugar composition analysis, the hemicelluloses were also elucidated by GPC, FTIR, NMR and AFM techniques. Xylose (33.70-74.09\%) and arabinose (25.03-59.04\%) were the main neutral sugar, with ratios of arabinose to xylose being between 0.34 and 1.70. GPC measurement showed that the fractions HPW, HP and HP precipitated in ethanol presented much broader molecular weight distribution. FTIR and NMR analysis suggested that the bamboo hemicelluloses could be mainly defined as arabinoxylans substituted by (1 -> 2)-linked 4-O-methyl-alpha-D-glucuronic aid and acetyl group as side chains. AFM images of HP revealed a distribution of both island and rod aggregations when 0.01 mg/mL sample in 0.1 M NH4Ac solution was deposited onto freshly cleared mica and air dried.
Lignin has a UV-blocking ability because it contains phenolic and ketone functional groups. However, the lignin produced in the paper industry undergoes extreme polycondensation, resulting in an extremely dark color, which impedes its value-added application in the field of UV-blocking cosmetics. In this study, maleic acid (MA) was used as a green and recyclable reagent to pretreat an agricultural waste lignocellulosic biomass, Kenaf stalk. Lignin underwent a carboxyl esterification reaction with MA to produce light-colored dissolved lignin (DL), which was further prepared into lignin nanospheres and used in lignin-based sunscreens. The results showed that when adding 5 wt\% DL-lignin nanospheres (DL-LNPs) to a sunscreen with an actual measured sun protection factor (SPF) of 7.05, the SPF of the lignin-based sunscreen increased to 63.82 far exceeding the commercially available SPF 50 sunscreens. The prepared lignin-based sunscreen had good biocompatibility when applied to human skin and did not stain the skin. The remaining neutral solid after pretreatment was made into Kenaf fibers by PFI milling for papermaking. The ring crush strength index of the paper increased from 2.81 N m/g to 3.14 N m/g when 15 wt\% Kenaf fibers was added to the softwood pulp. When the additions Kenaf fibers was 5 wt\%, the tensile index and tearing index of the paper increased from 8.57 N m/g and 4.68 mN m2/g to 9.22 N m/g and 5.48 mN m2/g, respectively. Therefore, this study provides a new way for the value-added utilization of Kenaf stalk lignocellulosic biomass.
Reducing the energy consumption in ceramic kilns because of lower firing temperatures is very relevant in terms of both fuel cost and carbon dioxide (CO2) emissions. In this sense, this work evaluates changes in the sintering starting temperature when ashes from the combustion of agro-industrial wastes (exhausted olive cake and almond shell) are added (0-20 wt\%) to two types of clays showing different plasticity and refractory behaviour. Both, reductions and increases in this temperature were measured by means of a Hot Stage Microscopy (HSM) which registers changes in the height of the sample subjected to a specific temperature profile. A selection of the more adequate clay-ash mixtures attending to their sintering behaviour were performed. Fired pieces of the selected mixtures were subjected to further characterization (tensile strength, linear shrinkage, firing loss, bulk density, porosity and water absorption) to evaluate mechanical performance when compared to the original clay. The results indicate that the sintering temperature of the clay-ash mixture is a compromise between the fluxing oxides content and the pores created by the loss of volatile matter and carbonates in the ash. While the former favours sintering, the latter inhibits it because of the appearance of gaps between mineral particles. Ash contents higher than 10\% did not provide benefits in terms of melting behaviour in any case. Reductions in the sintering starting temperature up to 120 degrees C were reported when ash from exhausted olive cake was used, which could lead to estimated fuel-energy savings around 2 (sic)/t of product (with around 6 kg/t of CO2 emissions avoided). Moreover, percentages above 5\% as well as the use of ashes from almond shells could be an attractive way for producing materials with enhanced insulation properties.
Xylitol is pentahydroxy sugar alcohol, existing in very trace amount in fruits and vegetables, and finds varied application in industries like food, pharmaceuticals, confectionaries, etc. and is of prime importance to health. Owing to its trace occurrence in nature and considerable increase in market demand that exceeds availability, alternate production through biotechnological and chemical approach is in process. Biochemical production involves substrates like lignocellulosic biomasses and industrial effluents and is an eco-friendly process with high dependency on physico-chemical parameters. Although the chemical processes are faster, high yielding and economical, they have a great limitation as usage of toxic chemicals and thus need to be regulated and replaced by an environment friendly approach. Microbes play a major role in xylitol production through a biotechnological process towards the development of a sustainable system. Major microbes working on assimilation of xylose for production of xylitol include Candida tropicalis, Candida maltose, Bacillus subtilis, Debaromyces hansenii, etc. The present review reports all probable microbial xylitol production biochemical pathways encompassing diverse bioprocesses involved in uptake and conversion of xylose sugars from agricultural residues and industrial effluents. A comprehensive report on xylitol occurrence and biotechnological production processes with varied substrates has been encompassed.
Biorefining of lignocellulosic biomass to fuels/chemicals has recently gained immense research momentum. Current study reports sequential pretreatment of sunflower stalk (SFS) biomass in a combinatorial regime involving alkali (NaOH) and ionic liquid 1-butyl-3-methyl imidazolium chloride. The pretreatment enhanced the enzymatic digestibility, and resulted in increased sugar yield (163.42 mg/g biomass) as compared to standalone pretreatment using alkali (97.38 mg/g biomass) or ionic liquid (79.6 mg/g biomass). Ultrastructural and morphological analysis (FTIR and SEM) of pretreated biomass showed that the combined ionic liquid and alkali pretreatment causes more drastic alterations in the biomass ultrastructure as compared to alone ionic liquid or alkali pretreatment. Thus, combined pretreatment led to ease of enzymatic saccharification and consequent increased sugar yield, and this observation was corroborated by physicochemical analysis of the pretreated biomass. The pretreated SFS biomass was subjected to consolidated bioprocessing for its direct conversion to bioethanol in a single vessel.
The developing of pretreatment method to break the biomass barrier of lignocellulosic is a challenging task for achieve high value utilization. A fast microwave-assisted choline chloride/1,2-propanediol/methyl isobutyl ke-tone biphasic system was constructed for pretreating Eucalyptus to the production of furfural and cellulose-rich residues and the extraction of lignin. Results showed that the combination of AlCl3.6H(2)O and HCl had the best catalytic ability for furfural production among the examined catalysts. Under the optimal conditions (140 degrees C, 15 min, 0.075 M AlCl3.6H(2)O, 0.05 M HCl), the furfural yield of 55.4 \%, the glucose yield of 90.3 \% and the delignification rate of 92.4 \% could be achieved. Moreover, the extracted lignin samples with a low poly-dispersity (1.55-1.73) and molecular weight (1380-2040 g/mol) are promising to act as precursor for the value -add products processing. These findings demonstrated an ultrafast pretreatment process with excellent results in biomass fractionation and comprehensive utilization of biomass components.
Although on-site cellulase production offers cost-effective saccharification of lignocellulosic biomass, low enzyme titer is still a barrier for achieving robustness. In the present study, a strain of T. reesei was developed for enhanced production of cellulase via overexpression of Cellobiohydrolase II. Furthermore, optimum enzyme production was achieved using a novel inducer mixture containing synthesized glucosesophorose (MGD) and alkali pre-treated corn stover (APCS). Within 60 h, a remarkably higher cellulase productivity and activity were achieved in the fed-batch fermentation using the optimized ratio of MGD and APCS in the inducer mixture, compared to those reported using cellulosic biomass as the sole inducer. After the enzyme production, APCS was added directly into the fermentation broth at 20\% solid loading, which produced 122.5 g/L glucose and 40.21 g/L xylose, leading to the highest yield reported so far. The improved enzyme titers during on-site cellulase production would benefit cost-competitive saccharification of lignocellulosic biomass. (C) 2017 Elsevier Ltd. All rights reserved.
The effectiveness of microwave assisted alkali (MAA) and alkaline hydrogen peroxide (AHP) pre-treatment methods in improving the enzymatic saccharification of cassava stem was investigated. Ground cassava stems were by MAA method by varying microwave power, NaOH concentration and pre-treatment time. AHP method was performed at various H2O2 concentrations, pre-treatment temperatures and times. The results showed that reducing sugar yield was higher from MAA pretreated stem when compared with AHP pre-treatment, which demonstrated that MAA pre-treatment was effective in releasing sugars. SEM studies on the pre-treated samples revealed extensive distortion of fibres in MAA pre-treated than AHP pre-treated samples, which showed pores and cracks in the fibrous structure. Spectral studies showed the change in the chemical structure of pre-treated samples. The work revealed that the studied pre-treatment methods were effective in improving the enzymatic saccharification of cassava stem.
Several organic (e.g., compost, hay, straw, grass) and inorganic (e.g., plastic film) ground cover (GC) forms are used in peach orchards worldwide. Yet, there is a lack of quantitative studies on peach orchard ecosystem services comprising fruit yields and quality, soil health indicators, and biological pest control. To fill this knowledge gap, we performed a meta-analysis of 55 peer-reviewed research. Overall, inorganic GC increased peach yields by 7.7 +/- 1.8\%, while organic GC reduced it, though not statistically significant (p > 0.05), by 1.7 +/- 3\%. Both forms of GC have enhanced single fruit mass, with a greater increase in inorganic (4.2 +/- 1.7\%) than in organic GC (1.2 +/- 1.2\%), and soluble solids content by 5.9 +/- 0.9\% and 3.2 +/- 0.7\%, respectively. Inorganic GC did not significantly affect titratable acid and fruit hardness, while organic GC reduced titratable acid (13.7 +/- 2.1\%), and fruit hardness (89 +/- 2.9\%). Soil temperature has increased in orchards with inorganic GC (2.8 +/- 2.9\%) and reduced with organic GC (8.3 +/- 2.4\%). Inorganic GC marginally increased soil water storage, while organic GC increased it by 9.3 +/- 2.1\%. Both organic and inorganic GC increased soil water content by 13.1 +/- 2.4\% and 26.1 +/- 3.4\%, respectively. Unlike inorganic GC, organic GC increased soil organic matter, available nitrogen, available phosphorus, and available potassium by 28.3 +/- 3.3\%, 25.1 +/- 2.7\%, 23.5 +/- 4.6\%, and 30.9 +/- 3.3\%, respectively. Equally significantly, organic GC increased predator abundance (47.5 +/- 5.9\%) and reduced pest incidence (2.4 +/- 1.8\%). Overall, inorganic GC systems slightly increased peach yield but are not sustainable due to their negative soil health and environmental impacts. In contrast, organic GC systems delivered an acceptable yield level while providing numerous ecosystem services, enabling sustainable long-term peach production.
The combination of hydrothermal pretreatment (autohydrolysis) and enzymatic hydrolysis was comprehensively evaluated for the efficient release of monosaccharides and ferulic acid from corn bran. Arabinan was depolymerized and solubilized more easily during autohydrolysis compared to xylan, esterified ferulic acid, and the acetyl group. Also, the enzymatic xylose yield showed strong linear correlation with arabinan, ferulic acid, and acetic acid content in autohydrolysis residues while correlations between enzymatic glucose yield and hemicellulose contents were separated into two stages with different slopes. The addition of a few debranching enzymes to commercial cellulase and xylanase only slightly enhanced enzymatic hydrolysis of autohydrolysis residues, whereas an enzyme blend from Aspergillus oryzae and Eapenicilliwn parvum showed a significant synergistic effect. Desirable combined hydrolysis yields of glucose (72.26\%), xylose (75.87\%), arabinose (76.95\%), and ferulic acid (74.13\%) were obtained after autohydrolysis at 165 degrees C for 40 min and subsequent hydrolysis by an equal mixture blend produced by A. oryzae and E. parvum at an enzyme loading dosage of 14.1 mg protein/g dry destarched corn bran.
In the present work, the slow pyrolysis has been executed in a tubular shaped fixed bed reactor using corn cob as biomass and superparamagnetic iron oxide nanoparticles (Fe3O4-NPs) as a catalyst. Fe3O4-NPs were fabricated by a facile novel biosynthetic route through a reduction of Fe (NO3)(3).9H(2)O with corn cob which acts as an excellent capping agent. The maximum yield of about 55.9\% bio-oil was achieved at 450(O)C in the presence of 2 g catalyst. Fourier Transform Infrared (FT-IR) spectra of Fe3O4-NPs, corn cob and biochar were scanned to explore the functionalities. The effects on product yields were studied under different settings of pyrolysis temperature and catalyst amount. Superparamagnetic Fe3O4-NPs manufactured by green method demonstrated high yield of bio-oil in a short time during pyrolysis and maximum percentage conversions of the pyrolytic products were achieved at 0.46-0.56 mm particle size. Corn cob residues used in pyrolysis is an alternative source of renewable energy sources and chemicals.
Lignin inhibitory becomes a major obstacle for enzymatic hydrolysis of empty fruit bunch conducted in high solid loading. Since current technology required high enzyme loading, surfactant application could not effectively used since it is only efficient in low enzyme loading. In addition, it will increase final operation cost. Hence, another method namely ``proportional enzyme feeding{''
The aim of present study was to obtain total reducing sugars (TRS) from bamboo under subcritical water (SCW) treatment in a batch reactor at the temperature ranging from 170 degrees C to 220 degrees C and 40 min hydrolysis time. Experiments were performed to investigate the effects of temperature and time on TRS yield. The maximum TRS yield (42.21\%) was obtained at lower temperature (180 degrees C), however longer reaction time (25 min). X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM) analysis were used to characterise treated and untreated bamboo samples. The XRD profile revealed that crystallinity of bamboo increased to 71.90\% with increase in temperature up to 210 degrees C and decreased thereafter to 70.92\%. The first-order reaction kinetic model was used to fit the experimental data to obtain rate constants. From the Arrhenius plot, activation energy and pre-exponential factor at 25 min time were found to be 17.97 kJ mol(-1) and 0.154 min(-1), respectively. (C) 2015 Elsevier Ltd. All rights reserved.
It is of the highest importance to study different alternatives/strategies as simultaneous (SSF) and semisimultaneous (SSSF) saccharification and fermentation process, as well as the prospects of the utilization of lignocellulosic residues as raw materials for fuel-ethanol production. In the first part of this work, different raw materials (cactus (CAC), green coconut shell (GCS), mature coconut fibre (MCF) and mature coconut shell (MCS)) were pretreated by sequential alkaline hydrogen peroxide (Alk-H2O2)-sodium hydroxide (NaOH) process. The characterization of the obtained solids by FTIR, SEM, X-ray and crystallinity indexes confirmed the higher susceptibility of these pretreated materials to enzymatic action. These results were further confirmed by the corresponding glucose conversion yields - 68.44\%, 70.20\%, 76.21\% and 74.50\% for CAC, GCS, MCF and MCS, respectively. Subsequently, the comparison between SSF and SSSF using Saccharomyces cerevisiae, Pichia stipitis, Zymomonas mobilis and pretreated MCF (selected in the enzymatic hydrolysis step) was done, being shown that a short presaccharification step at 50 degrees C for 8 h in the SSSF had a positive effect on the overall ethanol yield, with an increase from 79.27-84.64\% to 85.04-89.15\%. In all the cases, the SSSF strategy allowed the obtention of higher ethanol concentrations than SSF. (C) 2014 Elsevier Ltd. All rights reserved.
As the important structural component of corn stover, hemicellulose could be converted into a variety of high value-added products. However, high quality hemicellulose extraction is not an easy issue. The present study aims to investigate the effects of non-structural components (NSCs) and lignin removal on alkaline extraction of hemicellulose. Although NSCs were found to have a minimal effect on hemicellulose dissolution, they affected the color values of the hemicellulose extracts. The lignin limited the hemicellulose dissolution and increased the color value by binding to hemicellulose molecules and forming lignin-carbohydrate complexes. Sodium chlorite method can remove about 90\% lignin from corn stover, especially the lignin connected to hemicellulose through p-coumaric and ferulic acids. Which increased the hemicellulose dissolution ratio to 93\% and reduced the color value 14-28\%, but the cost is about 20\% carbohydrates lost. (C) 2016 Elsevier Ltd. All rights reserved.
Alkaline hydrogen peroxide pretreatment is an effectively enhance the increasing enzymatic digestibility of lignocellulosic biomass for conversion to fuels and chemicals in the biorefinery processes. In this study, effects of H2O2 on monomeric sugar in the liquid fraction during hydrogen peroxide pretreatment and sugar after enzymatic hydrolysis from corncobs were studied under varying reaction conditions. The temperature (30-120 degrees C) and H2O2 concentration (2.5-10\%) efficiently promoted sugar yield in the piqued fraction and improved enzymatic hydrolysis of pretreated solids. The optimal condition for H2O2 pretreatment of corncob (H2O2 concentration of 5\% using 60 degrees C for 2 h) increased hemicellulose solubilization into the aqueous phase, resulting into the maximized pentose yield of 61.88\% (xylose + arabinose) in the aqueous phase. H2O2 pretreatment under the optimal conditions at 60 degrees C for 2 h, leading to the enhance glucose yield from enzymatic hydrolysis of the pretreated biomass using 10 FPU/g CelluclastTM (85.66 \%) and small amount of formation of inhibitory by-products. Combined with glucose in the aqueous phase, this resulted in the maxima 95.61\% glucose recovery from the native corncob. This was related to changes in crystallinity and surface area of the pretreated biomass. Scanning electron microscopy (SEM) showed disruption of the intact biomass structure resulting increasing enzyme's accessibility to the cellulose microfibers which showed higher crystallinity index compared to the native biomass as shown by X-ray diffraction with a marked increase in surface area as revealed by BET measurement. The results provided efficiency of H2O2 pretreatment on increasing sugar recovery and an efficient approach for its processing in biorefinery industry.
The article is the analyses of the physical picture of the process of steam explosion treatment of pre-impregnated lignocellulosic material, on the basis of which the mathematical modeling is represented in the form of differential equations with boundary conditions. The obtained mathematical description allows to determine the degree of influence of various factors on the kinetics of the process.
Microwave pyrolysis is an efficient technique to valorize the abundantly available Prosopis juliflora (PJF) biomass into fuel intermediates. In this study, the effects of microwave power, susceptor, PJF particle size, PJF to susceptor mass ratio, and initial mass of PJF on bio-oil, gas, and char yields, composition of bio-oil, and energy recovery in bio-oil and char were evaluated. Five different susceptors, namely, graphite, char, aluminum, silicon carbide, and fly ash, an industry waste, were utilized. A high bio-oil yield of 40 wt \% with a heating value of 26 MJ kg(-1) was achieved with fly ash at a microwave power of 560 W, PJF particle size of 24 mm, and PJF (50 g)/fly ash composition of 100:1 (wt/wt). The bio-oil contained a mixture of phenolic compounds, aromatic hydrocarbons, cyclopentanones, carboxylic acids, ketones, and furan derivatives. Nearly 51\% deoxygenation of PJF was achieved with an atomic O/C ratio of 0.24 in bio-oil. This work demonstrates that the yield and quality of bio-oil are dependent on key parameters such as microwave power, biomass particle size/composition, and type of susceptor.
Purpose: This study was to confirm the safety and efficacy of BC dressing when used in surgical male wound healing at the urogenital area. Methods: Open, non-controlled clinical study of phase II. A total of 141 patients, among those children, adolescents and adults with hypospadias (112), epispadias (04), phymosis (13) and Peyronie's disease (12) that had a BC dressing applied over the operated area after surgery. A written informed consent was obtained from all participants. Study exclusion criteria were patients with other alternative treatment indications due to the severity, extent of the injury or the underlying disease. The outcomes evaluated were efficacy, safe and complete healing. The costs were discussed. Results: In 68\% patients, the BC dressing fell off spontaneously. The BC was removed without complications in 13\% of patients at the outpatient clinic during the follow-up visit and 17\% not reported the time of removal. In 3\% of the cases, the dressing fell off early. Complete healing was observed between 8th and 10th days after surgery. The BC dressings have shown a good tolerance by all the patients and there were no reports of serious adverse events. Conclusion: The bacterial cellulose dressings have shown efficacy, safety and that can be considered as a satisfactory alternative for postoperative wound healing in urogenital area and with low cost.
Alkaline potassium permanganate solution (APP) was applied to the pretreatment of corncob with a simple and effective optimization of APP concentration, reaction time, temperature and solid to liquid ratio (SLR). The optimized pretreatment conditions were at 2\% (w/v) potassium permanganate with SLR of 1:10 treating for 6 h at 50 degrees C. This simple one-step treatment resulted in significant 94.56\% of the cellulose and 81.47\% of the hemicellulose recoveries and 46.79\% of the lignin removal of corncob. The reducing sugar in the hydrolysate from APP-pretreated corncob was 8.39 g/L after 12 h enzymatic hydrolysis, which was 1.44 and 1.29 folds higher than those from raw and acid pretreated corncobs. Physical characteristics, crystallinity and structure of the pretreated corncob were analyzed and assessed by SEM, XRD and FTIR. The APP pretreatment process was novel and enhanced enzymatic hydrolysis of lignocellulose by affecting composition and structural features. (C) 2014 Elsevier Ltd. All rights reserved.
An efficient strategy was developed in current work for biochemical conversion of carbohydrates of corn stover into monosaccharides. Corn stover was first presoaked in mild alkaline solution (1\% Na2S) under 40 degrees C for 4 h, after which about 35.3\% of the lignin was successfully removed while the specific surface area was notably enlarged. Then the presoaked solids were subjected to organosolv pretreatment that employed 20\% methanol with an addition of 0.2\% HCl as catalyst at 160 degrees C for 20 min, and the maximum total sugar yield of the pretreated corn stover achieved was 98.6\%. The intact structure of corn stover was disrupted by this two-step process, which resulted in a porous but crystalline structure of the regenerated solids that were mainly composed of cellulose. The enlarged specific surface area and increased accessibility made the regenerated solids highly digestible by a moderate enzyme loading. (C) 2017 Elsevier Ltd. All rights reserved.
Lignocellulosic material (LCM) is promising alternative resource for sustainable energy production such as ethanol and butanol and biohydrogen. Cellulose is an abundant renewable polymer of LCM found in plant cell walls (30-50\%). The high crystallinity of cellulose makes it recalcitrant to hydrolysis into its individual sugar subunits for biofuels production. Moreover, ionic liquids are considered as green solvents and have been used for biomass solubilization. The present work describes three properties: Kamlet-Taft (K-T) parameters, viscosity and surface tension of five imidazolium-based ionic liquids (ILs); namely {[
Organosolv pretreatment can be considered as the core of the lignocellulosic biomass fractionation within the biorefinery concept. Organosolv facilitates the separation of the major fractions (cellulose, hemicelluloses, lignin), and their use as renewable feedstocks to produce bioenergy, biofuels, and added-value biomass derived chemicals. The efficient separation of these fractions affects the economic feasibility of the biorefinery complex. This review focuses on the simulation of the organosolv pretreatment and the optimization of (i) feedstock delignification, (ii) sugars production (mainly from hemicelluloses), (iii) enzymatic digestibility of the cellulose fraction and (iv) quality of lignin. Simulation is used for the technoeconomic optimization of the biorefinery complex. Simulation and optimization implement a holistic approach considering the efficient technological, economic, and environmental performance of the biorefinery operational units. Consequently, an optimized organosolv stage is the first step for a sustainable, economically viable biorefinery complex in the concept of industrial ecology and zero waste circular economy.
Dissolved organic carbon (DOC) in biochars is critical to carbon dynamics and contaminant transport in soils. This study aimed to develop a robust and easy method to characterize and quantify the biochar-DOC, using water-, acid-, and base-extractable DOC samples (WEOC, AEOC, and BEOC respectively) from 46 biochars produced from diverse feedstocks and pyrolysis conditions. BEOC concentrations were the highest (2.3-139 mgC/g-biochar), followed by WEOC (0.5-40 mg-C/g-biochar) and AEOC (0.2-23 mg-C/g-biochar). Fast-pyrolysis biochars generally had higher DOC concentrations than slow-pyrolysis biochars. DOC concentrations in slowpyrolysis biochars decreased exponentially with increasing pyrolysis temperature from 300 to 600 degrees C. The solidstate C-13 NMR showed that biochar-DOC had abundant small fused-ring aromatics, aliphatic C, and carboxyl C. Biochar-DOC included an acid-precipitated (AP) fraction of higher molecular weight and aromaticity and an acid-soluble (AS) fraction of lower molecular weight and aromaticity. BEOC generally had a greater AP fraction than WEOC and AEOC. Molecular weight, aromaticity and composition of AEOC and BEOC differed from those of more environmentally-relevant WEOC, suggesting that the acid- and base-extraction may not produce the DOC released in real soils. Finally, a quick, easy and robust UV-vis spectrometric method was developed to measure the composition and concentrations of WEOC in diverse biochar samples (R-2 = 0.96, n = 46).
The conversion of biomass into ethanol using fast, cheap, and efficient methodologies to disintegrate and hydrolyse the lignocellulosic biomass is the major challenge of the production of the second-generation ethanol. This revision describes the most relevant advances on the conversion process of lignocellulose materials into ethanol, development of new xylose-fermenting strains of Saccharomyces cerevisiae using classical and modern genetic tools and strategies, elucidation of the expression of some complex industrial phenotypes, tolerance mechanisms of S. cerevisiae to lignocellulosic inhibitors, monitoring and strategies to improve fermentation processes. In the last decade, numerous engineered pentose-fermenting yeasts have been developed using molecular biology tools. The increase in the tolerance of S. cerevisiae to inhibitors is still an important issue to be exploited. As the industrial systems of ethanol production operate under non-sterile conditions, microbial subpopulations are generated, depending on the operational conditions and the levels of contaminants. Among the most critical requirements for production of the second-generation ethanol is the reduction in the levels of toxic by-products of the lignocellulosic hydrolysates and the production of low-cost and efficient cellulosic enzymes. A number of procedures have been established for the conversion of lignocellulosic materials into ethanol, but none of them are completely satisfactory when process time, costs, and efficiency are considered.
Agave lechuguilla is a common plant of Northern Mexico that can be used as feedstock in the context of a biorefinery without competition for food use. In this work, the production of fermentable sugars from this biomass has been studied for the first time using dilute sulfuric acid pretreatment. An experimental design and response surface methodology were applied with temperature (160-200 degrees C) and acid concentration (0.5-1.5\% w/v) chosen as factors. The pretreatment conditions were expressed in a combined severity factor, which ranged from -0.75 to 2.38. According to an optimization criterion that maximizes hemicellulosic sugar recovery in the prehydrolysate and glucose recovery by enzymatic hydrolysis, optimal conditions for acid pretreatment of agave were found to be 180 degrees C and 1.24\% (w/v) H2SO4 at 10\% biomass loading. These optimal conditions yielded 87\% hemicellulosic sugar recovery and 68 g glucose/100 g glucose in raw agave. The whole slurry resulting from acid pretreatment of agave at optimal conditions was enzymatically saccharified yielding a sugar solution that was co-fermented by the ethanologenic Escherichia coil MM160. This process configuration allowed the fermentation of all sugars in raw A. lechuguilla in a single step reaching an ethanol yield of 73.3\%.
Organic waste generated from industrial sweet potato canning is estimated to be 30\% of incoming raw material with significant residual carbohydrate content. The purpose of this study was to evaluate the potential of waste generated from sweet potato processing material to support the growth of lactic acid bacteria and the production of lactic acid. The waste was comprised of 16.5\% solids consisting of 18.5\% ash, 4.4\% protein, 20.5\% simple sugars and 19\% soluble starch. Following a screening of three lactic acid bacteria strains, Lactobacillus rhamnosus was deemed the best candidate for lactic acid production. The potential of various dilutions of the enzyme-hydrolysed waste, with and without pH control, as a fermentation substrate was evaluated. Lactic acid production was highest in hydrolysed waste (without dilution) at pH set point 5.0, yielding 10gL(-1) in 72h. Thus, lactic acid, a valuable organic compound, can be generated from sweet potato waste.
BACKGROUND: Lignin inhibitory effects within the cell wall structure constitute a serious drawback in maximizing the utilization of fibrous feedstuffs in animal feeding. Therefore treatments that promote efficient delignification of these materials must be applied. This study evaluated the potential of white-rot fungi to upgrade the nutritive value of cowpea stover for rabbit feeding. RESULTS: There was an increase in the crude protein content of all substrates as a result of fungi treatments, reaching a net gain of 13\% for Pleurotus citrinopileatus incubation. Overall, net losses of dry and organic matter occurred during fungi treatments. Although the fiber content remained identical, higher consumption of cell wall contents was measured for P. citrinopileatus incubation (between 40 and 45\%). The incubation period did not influence lignin degradation for any of the fungi treatments. Differences within the fungal degradation mechanisms indicate that P. citrinopileatus treatment was most effective, enhancing in vitro organic matter digestibility by around 30\% compared with the control. CONCLUSION: Treatment of cowpea stover with P. citrinopileatus led to an efficient delignification process which resulted in higher in vitro organic matter digestibility, showing its potential in the nutritional valorization of this feedstuff. (C) 2017 Society of Chemical Industry
Corn stover is a promising feedstock for bioethanol production because of its abundant availability in China. To obtain higher ethanol concentration and higher ethanol yield, liquid hot water (LHW) pretreatment and fed-batch semi-simultaneous saccharification and fermentation (S-SSF) were used to enhance the enzymatic digestibility of corn stover and improve bioconversion of cellulose to ethanol. The results show that solid residues from LHW pretreatment of corn stover can be effectively converted into ethanol at severity factors ranging from 3.95 to 4.54, and the highest amount of xylan removed was approximately 89\%. The ethanol concentrations of 38.4 g/L and 39.4 g/L as well as ethanol yields of 78.6\% and 79.7\% at severity factors of 3.95 and 4.54, respectively, were obtained by fed-batch S-SSF in an optimum conditions (initial substrate consistency of 10\%, and 6.1\% solid residues added into system at the prehydrolysis time of 6 h). The changes in surface morphological structure, specific surface area, pore volume and diameter of corn stover subjected to LHW process were also analyzed for interpreting the possible improvement mechanism.
The objective of this study was to evaluate the influence of the total or partial replacement of Tifton 85 hay (TH) by cassava foliage hay (CH) and/or spineless cactus (SC) on the carcass characteristics and meat quality of confined lambs. Thirty-five Dorper x Santa Ines crossbred lambs were used, with an initial average weight of 16.0 +/- 1.9 kg, fed with five treatment diets: 70\% TH, 70\% CH, 35\% TH + 35\% CH, 35\% TH + 35\% SC, and 35\% CH + 35\% SC. After 90 days of confinement, the animals were slaughtered and the carcass and meat data were compared using the Tukey test at 5\%. The partial replacement of TH by SC increased the cold carcass weight by 3.9 kg (p < .05). The proportion of fat (\%) increased (p < .05) when TH was replaced by CH + SC. The intensity of red (a{*
The growth of oil exploration and transport in marine environments brings concern over potential environmental disasters caused by oil spills. Thus, various materials are being developed and studied in order to minimize environmental impacts caused by these oil spills. Among these materials, the use of sorbents has appeared as a great potential technique for the treatment of effluents, by separating and collecting oil in the aqueous medium. This work describes the development of a sorbent system based on acetylated microfibrillated cellulose. Initially, cellulose fibers were modified by an acetylation reaction and thereafter, by a mechanical process using a wheel mill grinding. To produce the sorbent system, fibers were coated by three different types of envelopes to prevent leakage during the sorption experiment. Main results indicate a higher oil sorption by sorbents with higher oil viscosity and higher grammage of the envelope. Acetylated microfibrillated cellulose showed low water adsorption and high selectivity to oil and greater oil sorption values than commercially sothent currently used, based on polypropylene fibers.
Pigment extraction from annatto seed results in large amounts of by-products (similar to 97\%) and residual carotenoid content. In this work, composite foam trays containing 90:10 (10AR), 80:20 (20AR), and 70:30 (30AR) cassava starch: annatto residue (AR) ratios were prepared by thermopressing. The physical-chemical properties, thermal stability, antioxidant activity, and biodegradability of the composite foam trays and cassava starch foam tray (control) were measured and compared. High AR ratio (20AR and 30AR) yielded thicker (2.1-2.3 mm), denser (0.72-0.74 g/cm(3)), and less porous (32.5-33\%) composite foam trays than the control due to incomplete cassava starch gelatinization and the presence of fibers, lipids, and proteins in AR. Thus, the composite foam trays had lower mechanical resistance (0.4-0.8 MPa) and elongation (0.4\%-0.7\%) than the control (2.9 MPa and 1.5\%). However, addition of high AR ratio increased the foam tray resistance to water and yielded colorful foam trays with antioxidant property as measured by DPPH center dot (0.11 to 0.52 mu M TE/100 g) and ABTS(center dot +) (7.86-53.77 mu M TE/100 g). Increasing the AR ratio in the composite foam tray delayed the biodegradation time by 17 days as compared to the control, but all the foam trays were more biodegradable than EPS. Therefore, AR has potential use in the production of bioactive composite foam trays.
Synthetic polymers are based on the use of crude oil as their raw material. Oil spillage takes place during production, storage, transportation and usage at the water bodies and land surfaces. This may be due to tanker disasters, wars, operation failures, equipment breaking down, accidents and natural disasters. The spilled oil into land, river or ocean imposes a major threat to the environment and endangers the aquatic life. To overcome this problem, oil sorbents are commonly used for cleaning the oil spills. In this paper, coir fibre which was obtained as a waste from coconut fruit was functionalized to increase its hydrophobicity and oil sorption capacity. The product so formed was characterized by FT-IR, TGA and SEM which confirmed grafting of butyl acrylate monomer onto the coir fibres. The effects of time, temperature and monomer concentration on the grafting of coir fibre and oil absorption capacity have also been investigated. Results demonstrated that the modified coir fibre absorbed fair amount of crude oil and studies also indicate that a simple squeezing was sufficient to remove most of the oil sorbed by the fibres so that the sorbents can be reused several times for oil spill clean-up.
Nonproductive adsorption of cellulase on lignin was a major inhibitory mechanism reducing the enzymatic saccharification efficiency of lignocellulosic material. The surface and structural properties of Fenton reaction-oxidized lignins (FRLs) and their effects on the nonproductive binding of enzymes to lignin and enzymatic saccharification of Avicel were examined. The Fenton chemistry pretreatment not only decreased the ratio of syringyl to guaiacyl units and the phenolic OH group content in lignin preparations but increased the carboxylic content and the negative zeta potential of lignin, all of which could be responsible for reducing the unproductive adsorption of cellulase on lignin. And Langmuir adsorption isotherms also proved that FRLs were provided with a lower binding ability to the cellulase enzyme when compared with untreated milled bamboo lignin (MBL). Finally, when the nonproductive binding of cellulase to FRLs was reduced significantly, the 72 h glucose yields of Avicel with 3-FRL and 5-FRL were 60.64\% and 65.96\%, respectively, which were 6.3-15.6\% higher than that of Avicel alone, 57.06\%. The results can also help to optimize the existing pretreatment technologies and develop new pretreatment methods that could produce less inhibitory lignin.
Room Temperature Ionic Liquids (RTILs) pretreatment are well-recognized to improve the enzymatic production of platform molecules such as sugar monomers from lignocellulosic biomass (LCB). The conditions for implementing this key step requires henceforth optimization to reach a satisfactory compromise between energy saving, required RTIL amount and hydrolysis yields. Wheat bran (WB) and destarched wheat bran (DWB), which constitute relevant sugar-rich feedstocks were selected for this present study. Pretreatments of these two distinct biomasses with various 1-ethyl-3-methylimidazolium acetate ({[
In this study, the effects of an alkali-acid purification process on the properties of eucalyptus lignin isolated from a methyl isobutyl ketone (MIBK)/methanol/water-based organosolv fractionation process were evaluated. The results showed that the treatment reduced the content of carbohydrates, ash, nitrogen and sulfur, and improved lignin solubility (up to 218\%) in five organic solvents (acetone, methanol, ethanol, tetrahydrofuran and dimethyl sulfoxide) and removed lignin fractions with smaller molecular weights. However, analysis by Py-GC/MS, solid state NMR and 2D-HSQC NMR indicated that the alkaliacid treatment process did not cause changes to the monomeric lignin subunits and linkages of the lignin polymer. The treated lignin showed slightly higher thermal stability at temperatures <250 degrees C, though its maximum rate of decomposition occurred at 325 degrees C, 26 degrees C lower than that of the untreated lignin. On the basis of these results, the significant improvement in solvent solubility of the lignin by the treatment process will widen lignin application.
The rising climate change concerns over the excessive exploitation of non-renewable sources have necessitated the need for alternative renewable and eco-friendly resources for the production of innovative materials, achieving the targets of bioeconomy. Lignocellulosic biomass (LB) constituted by polymeric sugars and lignin is an abundantly available plant-based renewable material in the form of agro-industrial food waste and crop residues that can be exploited for the production of an array of value-added chemicals and bioproducts. Cellulose is the most abundant natural and biodegradable organic polymer on earth derived from LB, with wide scale applications in the lignocellulosic biorefineries and food industries. The negative effects of food waste from agro-industrial activities could be reduced through the recovery of cellulose from these wastes and converting it into valuable forms. However, the extraction of cellulose from LB is a difficult task owing to the recalcitrant nature of biomass that restricts the easy accessibility of cellulose for value addition. Therefore, a suitable cellulose extraction method through the fractionation of LB is necessary for a better cellulose yield. Furthermore, owing to the enormous potential of nanocellulose (NC), researchers are keenly interested in developing ecologically acceptable cellulose extraction methods. Cellulose nanofibrils and nanocrystals confer excellent mechanical properties, non-toxic characteristics and biodegradability, due to which they possess wide-scale applications in diverse industrial sectors. The current review emphasizes the potential role of cellulose extraction and NC production from agro-food waste. The different pretreatment methods for their extraction from LB are outlined. The applications of nanocellulose in different areas are also discussed. The review also highlights the recent trends, challenges and future directions in the development of cellulose and NC-based commercial products.
This study aimed to investigate the effects of Kimchi cabbage by-products either treated or untreated with calcium oxide (CaO) and alkaline hydrogen peroxide (AHP) as substitutional ingredient of total mixed ration (TMR) on in vitro fermentation, in situ disappearance and growth performance of Holstein steers. Cannulated Holstein (600 +/- 47 kg) was used for both the in vitro and in situ experiments. The treatments used were TMR only (CON), TMR + 30\% Kimchi cabbage by-products fresh matter (FM) basis (TC), TMR + 30\% Kimchi cabbage by-products FM basis + 5\% CaO FM basis (TCC), and TMR + 30\% Kimchi cabbage by-products FM basis + 5\% CaO FM basis + 3.22\% AHP FM basis (TCCA). For in vivo experiment, thirty-four Holstein steers (273 +/- 45 kg) were subjected to a 150-day feeding trial, divided into two groups: CON and TC. In the in vitro experiment, pH of TCCA was greatest (p < 0.05) among other treatments at all incubation times. Ammonia nitrogen and volatile fatty acid concentrations were not significantly different for each treatment. However, butyrate was greater (p < 0.05) in TCC and CON than in both TC and TCCA. During in situ experiment, the dry matter (DM) disappearance was greatest (p < 0.05) in TCCA among other treatments. Also, disappearance of neutral detergent fiber (NDF) and acid detergent fiber (ADF) were observed greatest (p > 0.05) in TCCA treatment. In the in vivo experiment, average daily gain (ADG) did not differ between CON and TC. In blood profile analysis, alanine aminotransferase, aspartate aminotransferase, glucose, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and total protein concentration were not significantly different between treatments. But, creatinine concentration was greater (p < 0.05) in TC than in CON. Overall results suggest that Kimchi cabbage by-products either treated or untreated with CaO and AHP can be used as substitutional ingredient in TMR for Holstein steers.
Two ultrasound-assisted pretreatment technologies, ultrasound-assisted alkaline and ultrasound-assisted aqueous ionic liquid tetrabutylammonium hydroxide ({[
The disposal and waste management of solid high energy propellant (HEP) is a considerate conservational problem. HEP waste is currently disposed in open or confined burning which may cause environmental hazards. In this paper, we examined and discussed results on recycling of HEP waste into fired clay bricks baked in different orientation. HEP modified bricks with 1.5\%, 3\% and 5 wt. \% HEP waste content were manufactured and tested, and then compared against virgin clay bricks without HEP content. The effect of directional orientation of bricks baked with varying HEP content on acoustic properties were experimented and discussed. The sound transmission loss decreases with increase in HEP waste due to formation of independently closed directional pores. The transmission loss of horizontally baked during firing of bricks is nearly 5dB lower than vertically baked bricks. Results of the experimental studies indicate that HEP waste can be utilised in fired clay bricks and different orientation baking further enhances the acoustic properties.
The effect of mixing low amounts of orange peel (Citrus reticulata) with a soil contaminated with hydrocarbons (58,000 mg kg(-1) soil) for promoting the soil remediation in solid culture was studied. The experimental design was established in solid culture at soil/orange (Citrus reticulata) peel ratios of 100:0, 98:2, 96:4, 94:6 and 92:8, at 30\% humidity and a C:N:P ratio of 100:10:1, for 15, 60 and 90 days, respectively. The total petroleum hydrocarbons (TPHs) decreased significantly (69\%) after 15 days in the treatment with a soil to orange peel ratio of 92:8. Furthermore, in this treatment bacterial counts increased from 17 to 20 ln CFU (2.6 x 10(6) to 5 x 10(8)), while the fungal count was 11 ln CFU (6.5 x 10(4)) at initial and final time of treatment. An increase in microbial respiration activity and TPH removal (69\%) was observed at other soil/orange peel ratios after 60 days when moisture content and nutrients were adjusted; however, N and P were not consumed at a great extent.
An efficient fractionation of three main components of corn cob and a good delignification effect were reported with formic acid (88\%) pretreatment at 80 degrees C for 3 h. The pretreated substrate demonstrated a poor enzymatic digestibility with a mere 9.1\% hydrolysis yield. Subsequently, various post-treatment processes after pretreatment were conducted and the mechanisms behind the effect on the hydrolysis were investigated. During pretreatment, formic acid adsorption occurred, which resulted in a significant inhibiting effect for the hydrolysis of the pretreated substrate. Mild post-treatment quickly removed the easily desorbed formic acid in the solid and cellulose accessibility was found to be increased greatly along with the decrease of formic content. After hot water and alkaline salt post-treatment, the hydrolysis yield increased to 81.2\% and 98.5\%, respectively. Meanwhile, the formic acid content of the substrate decreased by 15.9\% and 61.4\%. The restarted hydrolysis performance indicated that the factor associated with the nature of substrate, such as formic acid content, cellulose accessibility, and the existence of ester bonds, should be responsible for the enzymatic digestibility of the substrate. Herein, the proposed two-step pretreatment with formic acid (88\%) followed by alkaline salt solution at room temperature demonstrates a remarkable effect on the conversion of lignocellulose material and has high feasibility for industrial application since it is mild to environment and requires low energy. {[
Microorganisms play an important role in the bioconversion of organic residues and have therefore become promising for obtaining value-added enzymes. In an attempt to take advantage of the by-products and residues of bioconversion, this work sought to use lignocellulosic fractions extracted from corncob as fermentation substrate for ligninase induction by Pleurotus sajor-caju. To obtain the corncob lignocellulosic fractions, biomass was submitted to treatment by alkaline extraction (NaOH 0.75 mol L-1, 55 degrees C for 2 h) and organosolv (40\% ethanol/water, 185 degrees C for 20 min). The in natura biomass and lignocellulosic fractions were used as substrates in the subsequent fermentation processes: 2\% in natura corncob; 2\% cellulose-lignin complex fraction; 2\% lignin-enriched fraction; 1\% lignin-enriched fraction; and synthetic medium fungal (SMF) as standard. Chemical and physical-chemical analyses indicated the effectiveness of the lignocellulosic extraction process. According to the results, the developed system promoted the induction of ligninases by P. sajor-caju. The enzymatic analysis showed laccase production (768 U L-1) using the 1\% lignin-enriched fraction as substrate. Manganese peroxidase production was 1050 U L-1 with the use of the 2\% lignin-enriched fraction. The presence of lignocellulosic fractions extracted from corncob's lignin-enriched fraction in the culture medium favored the induction of ligninases in comparison to the use of residue alone.
Natural polymeric materials are an interesting alternative to petrochemical products with potential application in almost all areas of human activity. Wishing to expand the field of cellulose acetate application to the biocomposite wood materials, the possibilities of cellulose isolation and its acetylation from two domestic, commercially meagrely used, wood species was investigated in this paper. Cellulose isolated from white willow (Salix alba) and black alder (Alnus glutinosa) was acetylated using acetic anhydride and perchloric acid catalyst, by treatment at room temperature for 45 minutes. Analysis of the laboratory acetylation process, beside chemical analysis of the gained product by infrared spectroscopy (FT-IR), indicated the impact of hemicelluloses, present both in cellulose and cellulose acetate structure, on values of mass increase, number of acetyl groups and the degree of substitution. Results of thermogravimetric analysis (TGA) later confirmed the statement that thermal properties of cellulose acetate were also dependant on hemicelluloses.
The pulverized A. cosmosus peel was found to contain 25 +/- 0.31 \% cellulose, 28 +/- 0.18 \% hemicellulose and 8 +/- 0.07 \% of lignin on dry solid basis. 1 \% H2SO4 delignified A. cosmosus peel yielded 38.81 \% xylose, 29.31 \% fructose and 18.89 \% glucose under steam explosion, with a hydrolytic efficiency of 75.52 \%. Fourier transform infrared spectroscopy results not only indicated the penetration of H2SO4 in the amorphous region of the biomass and degradation of hemicelluloses but also shows the structural differences before and after pretreatment. Simultaneous Saccharification and Fermentation of pretreated A. cosmosus peel by cellulase and Mucor indicus MTCC 4349 were investigated in the present study. Important process variables for ethanol production from pretreated A. cosmosus peel were optimized using Response Surface Methodology (RSM) based on central composite design (CCD) experiments. A three level CCD experiments with central and axial points was used to develop a statistical model for the optimization of process variables such as incubation temperature (30, 32 and 34 degrees C) X1, inoculum level (2, 4 and 6 \%) X2 and nutrients (1/2/3) X3. Data obtained from RSM on ethanol production were subjected to the analysis of variance and analyzed using a second order polynomial equation and contour plots were used to study the interactions among three relevant variables of the fermentation process. The fermentation experiments were carried out at flask level. The processing parameters setup for reaching a maximum response for ethanol production was obtained when applying the optimum values for temperature (30 degrees C), inoculum level (2 \%) and fermentation medium (urea, NaH2PO4, tryptone and meat extract) for Mucor indicus MTCC 4349. Maximum ethanol concentration 10.4293 g/l was obtained after 72 h from Mucor indicus MTCC 4349 at the optimized process conditions in aerobic batch fermentation.
The process of corn cobs alkaline hydrolysis to produce solutions with high hydroxy-cinnamic acids content was investigated. In particular the attention was focused on the solubilisation of ferulic acid (FA) and related compounds, mainly p-coumaric acid (p-CA). Although these compounds have applications as antioxidants, the purpose of this work was to obtain FA solutions that can be used as feedstock for the biotechnological production of vanillin in future studies. The effects of different concentrations of NaOH (0.2 <= C-a <= 2.0N) and solid/liquid ratios (0.028 <= S/L <= 0.168 g/g) on the solubilisation of FA versus time have been investigated at room temperature. Optimal hydrolysis conditions (C-a =0.5N, S/L=0.084 g/g after 6 h) ensured the production of hydrolysates with relatively high contents of both FA (1171 34 mg/L) and p-coumaric acid (2156 +/- 64 mg/L), which can be used in future studies for the microbial transformation into vanillin. (c) 2008 Elsevier B.V. All rights reserved.
Chemical modification is the most important method to design novel biopolymer and biomaterials from the abundant and biocompatible hemicelluloses. In this paper, an efficient method to synthesize hemicellulosic derivatives with bifunctional groups was developed by the etherification of hemicelluloses with acrylamide in the butanol/water medium. Varying the reaction condition such as reaction time, reaction temperature, and the amount of acrylamide and so on, the optimized hemicellulosic derivative with a higher total degree of substituent (DS) of 0.92 and with the 0.43 ratio of carbamoylethy groups and carboxyethyl groups was obtained. C-13 NMR analysis showed that the etherification occurred preferably at C-3 position of xylose. A significant degradation of the polymers occurred during the etherification. The shear-thinning of the hemicellulosic derivatives became more dramatic. The solution of the hemicellulosic derivatives showed lower viscosity and modulus as compared with the native hemicelluloses, exhibiting a less elastic behavior. (C) 2010 Elsevier Ltd. All rights reserved.
The enzymatic saccharification of regenerated lignocellulose must occur separately due to the toxicity of ionic liquids to cellulase. Therefore, it is important to develop a biocompatible IL-cellulase system which effectively achieves activation and saccharification of lignocellulose. For this purpose, a dual-phase ``enzyme-shuttling compartment `` was constructed in this study. Tween 80 was found to form reverse micelles in the isooctane-IL two-liquid phase, acting as a microenvironment that maintains the energetic conformation of the reactive cellulase. The activated bamboo biomass was enzymatically hydrolyzed in 20\% (w/v) 1-ethyl-3-methylimidazolium dimethyl phosphate and 50 mM citrate buffer at 50 ?, achieving a high total reducing sugar yield of 71.2\% and maintaining an enzymatic activity of 91.2\% after 24 h. Thus, an efficient system with the simultaneous activation and saccharification of natural biomass was successfully developed in a one-pot procedure at low temperatures, ensuring large-scale biomass conversion into biofuels and biological products.
Miscanthus, a high yield and low maintenance perennial plant with a high cellulose fiber contents, is a potential feedstock for pulp production. In this study, a binary enzyme cocktail of cellulase and laccase was employed for the extraction of cellulose microfibers from miscanthus biomass. The effect of enzyme concentrations (0.10\%, 0.15\%, 0.20\%, and 0.25\%, w/w) for the binary enzymes (cellulase-laccase: 1:1 ratio) pre-treatments on pulp and hand-sheet materials were studied and compared with those prepared from the single enzyme (cellulase or laccase) pre-treatment. The binary enzymes concentration at 0.25\% (w/w) showed the maximum extraction yield of cellulose (47.2\%, w/w) and lignin (27.9\%, w/w). The resulting fibers had 43.7\% crystallinity, a degree of polymerization of 1435, a water retention value of 312.7\%, and a crystallite size of 23.4 nm. Furthermore, the resulting fibers from binary enzymes concentration at 0.25\% (w/w) exhibited a higher thermal stability and fibrillated strands than those obtained from the single enzyme pre-treatment. Hand-sheets developed from the cellulose microfibers extracted by the enzyme cocktail at 0.25\% (w/w) enzyme concentration showed higher mechanical properties and water absorption capacity than those prepared from the single enzyme pre-treatment.
Nanocelluloses, including cellulose nanocrystals (CNCs), bacterial nanocellulose (BNC), and cellulose nanofibrils (CNFs), have attracted much attention in recent years all over the world. However, commercial applications of nanocelluloses are still limited due to the high cost of nanocelluloses. In this study, we developed a novel method to prepare lignocellulose nanofibrils (LCNF) directly from bamboo chips (BC), which can readily be scaled up. The method developed consists of three primary steps, which are as follows: glycerol pretreatment, screw extrusion, and mechanical refining/milling in a colloid mill. Glycerol can readily penetrate into bamboo chips and it is used as an effective reaction medium for fibrillation and delignification. The LCNF yield is about 77.2\% based on bone dry bamboo chips. The morphology of the LCNF was investigated by transmission electron microscopy (TEM), which shows that the LCNFs have a diameter of 20-80nm and a length of several thousand nanometers. X-ray diffraction (XRD) analysis shows that the crystallinity of the LCNF was 52.7\%, which was slightly lower than that of the bamboo raw material. This process can be easily scaled up for commercial production of LCNF.
Background: In the present study, three ionic liquids, namely 1-butyl-3-methylimidazolium chloride ({[
This work performs the ethanol production by a fermentation approach based on three banana residues simultaneously (banana pulp and peels, and banana pseudostem) in the realistic proportion (1:2:10) as generated at harvest and commercialization. A process model was developed using a commercial simulator to assess the energy consumption, inputs, and ethanol production, aiming to carry out a preliminary economic analysis for large-scale production in Brazil. Five scenarios for large and medium-sized plants installed in the state of Santa Catarina were created, seeking the lowest logistic cost. Two types of inoculums were chosen in the fermentations: with a monoculture of Saccharomyces cerevisiae, and with a coculture of Saccharomyces cerevisiae and Pachysolen tannophilus (ATCC32691). The highest ethanol yield (0.4 g/g), volumetric productivity (1.1 g/L h), and annual production (32.713 m(3)) with lower energy expenditure (138.4 GJ/m(3)) were obtained with fermentation by co-culture with wet pseudostem in the composed broth. Massaranduba is considered the most appropriate municipality of Santa Catarina state for the installation of a biorefinery. In an optimistic scenario, where the energy cogeneration would meet the plant's energy demand, the proposed process is economically viable, with the lowest payback time of 12.4 yr.
The aim of this work was to optimize the delignification of the hemicelluloses-free fraction of rice husk to obtain fractions of lignin, cellulose, and inorganics, which could be valorized in the context of the rice husk biorefinery. The hemicelluloses were pre-extracted from the raw material by dilute sulfuric acid, and a soda-ethanol-water process was used for delignification. Two experimental designs were carried out to evaluate different ranges of the same variables (strong and light conditions), aiming to promote maximal delignification or delignify while protecting carbohydrates. The optimal delignification points were obtained using 13 and 8\% of NaOH (\%w/w on solid material), in a 50:50 and 54:46 ethanol:water solution. In these conditions, 94.3 and 90.1\% of lignin and almost 100 and 40\% of inorganics were removed from the solid, respectively. The used soda-ethanol-water process can be defined as a soda process additivated with ethanol, showing significant advantages over soda-anthraquinone process for the fractionation of lignocellulosic materials. (C) 2016 Elsevier B.V. All rights reserved.
The flame propagation of an ammonia-hydrogen blended fuel through a porous medium was theoretically and experimentally evaluated in the present study. The laminar flame speed of ammonia-air mixtures is relatively low. The addition of traditional fuels to these mixtures is a feasible method for promoting and maintaining the flame stability of the mixtures. Moreover, the intrinsic characteristics of porous media enhance the heat transfer and heat recovery phenomena, which increases the combustion stability. In this study, a theoretical analysis based on the modified Peclet number and Lewis number was performed to estimate whether an ammonia-hydrogen flame can propagate through a porous medium, and the results of this analysis were verified through experiments.
Soil acidification is the main cause for aggravation of soil cadmium (Cd) pollution. Biochar treatment can increase the soil pH and decrease the Cd availability in soils. However, there is limited information in literature on the comprehensive assessment of the response of Cd fractions to biochar. Therefore, in the present meta-analysis study, we evaluate the response of Cd fractions to biochar application in soils with different pH and to further examine the effect of physicochemical properties of biochar on Cd. Results from the overall analysis indicated that biochar treatment increased the soil pH by 7.0\%, thereby decreasing the amount of available Cd (37.3\%). In acidic soil, biochar significantly reduced the acid-soluble fraction (Acid-Cd) of Cd by 36.8\%, while Oxidizable fraction of Cd (Oxid-Cd, 20.9\%) and Residual fraction of Cd (Resid-Cd, 22.2\%) were significantly increased. In neutral soils, only Acid-Cd was significantly reduced (33.0\%) in the presence of biochar. In alkaline soils, biochar caused significant reduction in Acid-Cd of 12.4\% and an increase in Oxid-Cd and Resid-Cd of 26.6\% and 47.8\%, respectively. Further, our findings showed that biochar with cation exchange capacity >100 cmol+/kg effectively decreased Acid-Cd (32.4\%), while biochar with the percentage of hydrogen <2\% was more contributory in increasing Resid-Cd (64.3\%). These results demonstrate the importance of soil pH in regulating the biological effectiveness of Cd in soil and the complexation between the functional groups of biochar and Cd, and provide key information for the remediation of Cd pollution in soils with different pH by biochar.
A laboratory study was undertaken to extract nano-fibrillated cellulose (NFC) from the pseudostem (a waste from the fruit harvest) of two commercial banana cultivars ('Grand Naine' and `Poovan') in Tamil Nadu using a novel approach: a one-step method with a bleaching agent and alkali-free acid hydrolysis coupled with ultrasonication. The acid hydrolysis was performed using nitric acid and acetic acid (1:10 ratio). The treatment was effective in the depolymerization and defibrillation of banana pseudostem fiber and in the formation of NFC, which was confirmed by several physico-chemical techniques. The average diameters of the nanofibrils were 6 to 8 nm and 4 to 6 nm for `Grand Naine' and `Poovan', respectively. The XRD analysis revealed an increased cellulose crystallinity of almost 20\% in the NFC compared with the respective raw banana fibers. The Fourier transform infrared (FT-IR) spectroscopy and thermal gravimetric analysis (TGA) confirmed the absence of lignin, hemicelluloses, and pectin in the nano-fibrillated samples. The thermal analysis showed the increased thermal stability of the NFC.
Pilot-scale steam explosion equipments were designed and constructed, to experimentally solubilize xylose from oil palm empty fruit bunches (OPEFB) and also to enhance an enzyme accessibility of the residual cellulose pulp. The OPEFB was chemically pretreated prior to steam explosion at saturated steam (SS) and superheated steam (SHS) conditions. The acid pretreated OPEFB gave the highest xylose recovery of 87.58 +/- 0.21 g/kg dried OPEFB in the liquid fraction after explosion at SHS condition. These conditions also gave the residual cellulose pulp with high enzymatic accessibility of 73.54 +/- 0.41\%, which is approximately threefold that of untreated OPEFB. This study has shown that the acid pretreatment prior to SHS explosion is an effective method to enhance both xylose extraction and enzyme accessibility of the exploded OPEFB. Moreover, the xylose solution obtained in this manner could directly be fermented by Candida shehatae TISTR 5843 giving high ethanol yield of 0.30 +/- 0.08 g/g xylose. (C) 2015 Elsevier Ltd. All rights reserved.
Chlorogenic acid (CGA) is a natural compound with potent antioxidant and antibacterial properties that can be extracted from Eucommia leaves (EL). In this study, we investigated eight natural deep eutectic solvents (NADES) for their effectiveness in extracting CGA from EL. The extractability, stability, antibacterial and antioxidant activity of the CGA extracted by NADES were evaluated and compared with traditional solvent extraction. The results of the study revealed that the highest efficiency in extracting CGA was achieved using choline chloride-malic acid (ChCl-MA) NADES, which can be recycled four times. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) characterization of solid residues confirmed high extraction. The acidic and high-strength hydrogen-bonding features of ChCl-MA contribute to the enhanced stability of CGA. The presence of malic acid components in ChCl-MA can synergistically improve the antioxidant and anti-microbial bioactivity of the extraction solution. The results of this study provide a promising and sustain-able method for NADES to extract natural products in food chemistry and pharmacy.
Nowadays, there are competing product development based on natural fiber which renewable, environmentally acceptable, and biodegradable reinforcing fiber. Also, combine acceptable mechanical properties with a low density. The major challenge for natural fiber composites is their inherent poor adhesion between fiber and the,matrix, high moisture absorption and UV degradation. Lignin and hemicelluloses are the components of natural fiber which are mostly responsible for moisture absorption and UV degradation. In this study the lignocelluloses (Oil Palm Empty Fruit Bunch) were treated with alkaline peroxide to remove lignin and hemicelluloses. Composites were produced with treated and untreated fiber using up to 45\% fiber with polypropylene (PP) matrix using Twin-screw extruder followed by injection molding. Composites were characterized using tensile and flexural testing, SEM and TGA. The tensile and flexural modulus were found to be higher for alkaline peroxide treated fiber composites compared to untreated fiber composites.
Increasing reducing sugars (xylose and glucose) yield for bioethanol from corn stover depends strongly on optimization of pretreatment conditions. The optimum reaction conditions of two-stage liquid hotwater (LHW) pretreatment based on total sugars yield were investigated. Under optimal conditions, the recovery of glucose of corn stover after two-stage LHW pretreatment and 72 h enzymatic digestion, reached 89.55\%. In addition, acetic acid-rich spent liquor pretreatment and one-stage LHW pretreatment have been carried out to make comparisons with two-stage LHW treatment. Glucose yield 89.55\% is superior to the recovery 83.38\% using acetic acidrich spent liquor pretreatment or 80.58\% using one-stage LHW pretreatment. The production of total sugars was increased by 7.8\% when compared with one-stage pretreatment. Moreover, the structural features of the treated corn stover solid residueswere also investigated by XRD and SEM technology in order to clarify the effects of the reaction on corn stover. The results indicated that the two-stage LHW pretreatment was an effective pretreatment method of corn stover to get most massive resource utilization, and it could be successfully applied to corn stover. (C) 2017 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved.
Lignocellulosic biomass is a renewable and abundant resource that is suitable for the production of bio-based materials such as biofuels and chemical products. However, owing to its complex chemical composition, it requires a process that enhances the release of sugars. Pretreatment is an essential stage in increasing the efficiency of enzymatic hydrolysis of lignocellulosic biomass. The most widely used pretreatment methods operate at high temperatures (160-290 A degrees C) and pressures (0.69 to 4.9 MPa) and generate biological growth inhibitors such as furfural and hydroxymethylfurfural (HMF). Thus, there has been a growing need to adopt new approaches for an effective pretreatment that operates at ambient temperature and pressure and reduces the generation of inhibitors. Among these methods, alkaline hydrogen peroxide (AHP) is notable because it is effective for a wide range of lignocellulosic biomass concentrations, and can provide a high degree of enzymatic hydrolysis efficiency. However, few results have been discussed in the literature. Given this, the aim of this study was to investigate the use of alkaline hydrogen peroxide (AHP) as an oxidative pretreatment agent to improve the efficiency of enzymatic hydrolysis for different types of biomass and examine the key areas of the pretreatment. Finally, there is a discussion of the challenges facing a large-scale application of this method.
In this study response surface methodology (RSM) was applied to study the effect of H2SO4 concentration, temperature, and time on the production of reducing sugars, total sugars, and total phenolic compounds from pine needles. Three variables with three levels showed that maximum release of total phenolic compounds (31.20 +/- 0.002 mM) was observed at 1\% H2SO4 concentration, 130 degrees C temperature for 75 min of residence time. Under these conditions, the predicted value of total phenolic compounds was 31.27 mM, which indicated that the model is valid, having negligible variation in observed and predicted values. These results suggested that this substrate could be potentially used as substrate for bioethanol production.
The development of technologies to ferment carbohydrates (mainly glucose and xylose) obtained from the hydrolysis of lignocellulosic biomass for the production of second-generation ethanol (2G ethanol) has many economic and environmental advantages. The pretreatment step of this biomass is industrially performed mainly by steam explosion with diluted sulfuric acid and generates hydrolysates that contain inhibitory compounds for the metabolism of microorganisms, harming the next step of ethanol production. The main inhibitors are: organic acids, furan, and phenolics. Several strategies can be applied to decrease the action of these compounds in microorganisms, such as cell immobilization. Based on data published in the literature, this overview will address the relevant aspects of cell immobilization for the production of 2G ethanol, aiming to evaluate this method as a strategy for protecting microorganisms against inhibitors in different modes of operation for fermentation. This is the first overview to date that shows the relation between inhibitors, cells immobilization, and fermentation operation modes for 2G ethanol. In this sense, the state of the art regarding the main inhibitors in 2G ethanol and the most applied techniques for cell immobilization, besides batch, repeated batch and continuous fermentation using immobilized cells, in addition to co-culture immobilization and co-immobilization of enzymes, are presented in this work.
To elevate the glucose yield from the enzymatic hydrolysis of poplar wood for bio-ethanol production, quick hydrothermal treatment (QHT) was conducted at 200 degrees C for a short period of time from 5 min to 25 min. It was found that the QHT could remove> 85\% of the hemicelluloses and similar to 30\% of the lignin in the poplar wood, and achieve 82\% cellulose conversion at a low cellulase dosage of 10 FPU/g substrate. The enhancement digestibility of poplar wood was ascribed to the higher accessibility of cellulose, as the specific surface area of the substrate increased from 3.0 m(2)/g to 7.1 m(2)/g from the of untreated wood to the QHT-treated wood. The results demonstrate the improvements in digestibility and hydrolysis rates after QHT.
This study introduces a facile and green route to fabricate film from bio-based polymers. The film has been prepared by the cross-linking reaction of quaternized hemicelluloses (QH) and chitosan (CHO) with epichlorohydrin (ECH) as crosslinker. It exhibits an excellently mechanical performance as a result of its high tensile strength (up to 37 MPa). Importantly, the roughness of film was 2-5 nm in the area of 400 nm, and smooth surface with pores were presented on the film based on the results of scanning electron microscope (SEM) and atomic force microscope (AFM). Ciprofloxacin was utilized as a mode compound to investigate the loading behavior of the film, and the highest loading concentration was about 18\%. The drug release was about 20\% in filml in comparison to only 15\% in film3 within 48 h. Furthermore, the results of a 293T cell viability assay indicated its good biocompatibility and non-toxicity. (C) 2016 Elsevier Ltd. All rights reserved.
Ethanol is the main biofuel produced by fermentation route and the search for new feedstocks to produce fuel ethanol is still a great challenge. This work aims to compare the ethanol production from a new irrigated rice cultivar BRS AG to the conventional cultivar BRS PAMPA applied in Brazil. Six different commercial strains of Saccharomyces cerevisiae (BG-1, CAT-1, FT-858, JP-1, PE-2, and SA-1) were applied in fermentation reactions. Fermentations performed with BRS PAMPA rice revealed that the highest yields were achieved with strain SA-1, corresponding to 93.0\% of the theoretical maximum and final ethanol concentration of 58.92 g L-1, and with CAT-1, a yield of 92.7\% and final ethanol concentration of 58.93 g L-1. For the fermentations with BRS AG rice, the highest yields were obtained with strain FT-858, exhibiting a 89.6\% yield and final ethanol concentration of 62.45 g L-1, and with CAT-1, 87.9\% yield and final ethanol concentration of 61.25 g L-1 were achieved. The most appropriate microorganism for ethanol production using BRS PAMPA rice and BRS AG rice was CAT-1. Comparatively, the ethanol yield and productivity using BRS AG were higher than those observed for BRS PAMPA for all strains, except for PE-2 and SA-1 that led to very similar results. The experimental results showed that the giant rice BRS AG is an excellent feedstock for fuel ethanol production in lowland fields.
Biomass to biofuels production technology appears to be one of the most sustainable strategies among various renewable energy resources. Herein, pretreatment is an unavoidable and key step to increase free cellulose availability and digestibility to produce green fuels. Various existing pretreatment technologies of lignocellulosics biomasses (LCBs) face distinct challenges e.g., energy consuming, cost intensive, may lead partial removal of lignin, complex inhibitors production as well as may cause environmental pollutions. These, limi-tations may be overcome with the application of nanomaterials, employed as nanocatalysts during the pre-treatment process of LCBs. In this prospect, the present review focuses and summarizes results of numerous studies and exploring the utilizations of magnetic, carbon based nanostructure, and nanophotocatalysts mediated pretreatment processes along with their possible mechanisms to improve the biofuels production compared to conventional chemical based pretreatment approaches. Furthermore, different aspects of nanomaterials based pretreatment methods with their shortcomings and future prospects have been discussed.
The present work emphasizes to develop a cog-effective process for the saccharification of lignocellulosic agro-wastes viz., husks of corn, peanut and coffee cherry, utilizing the consortium of crude lignocellulolytic enzymes produced by the newly isolated Sphingobacterium sp. ksn followed by fermentation process with yeast strains. The agro-residues were subjected for steam pretreatment before enzymatic hydrolysis and compared with NaOH or H2SO4 pretreatments. Corn husk was found to be the best substrate for enzymatic hydrolysis for the production of fermentable sugars. The Saccharomyces cerevisiae and Candida tropicalis were employed individually or as co-culture for fermentation of the hydrolysate obtained after enzymatic breakdown of steam treated agro-residues. The maximum ethanol produced by utilizing enzymatic hydrolysate of the steam treated husk of corn as substrate by separate hydrolysis and fermentation were 20.61, 5.81 and 18.21 g L-1 respectively, whereas 20.66 and 5.85 g L-1 were acquired from the corresponding immobilized yeast cells after 72h of fermentation.
This study aimed to select thermotolerant yeast for bioethanol production from cellulose-rich corncob (CRC) residue. An effective yeast strain was identified as Saccharomyces cerevisiae TC-5. Bioethanol production from CRC residue via separate hydrolysis and fermentation (SHF), simultaneous saccharification and fermentation (SSF), and prehydrolysis-SSF (pre-SSF) using this strain were examined at 35-42 degrees C compared with the use of commercial S. cerevisiae. Temperatures up to 40 degrees C did not affect ethanol production by TC-5. The ethanol concentration obtained via the commercial S. cerevisiae decreased with increasing temperatures. The highest bioethanol concentrations obtained via SHF, SSF, and pre-SSF at 35-40 degrees C of strain TC-5 were not significantly different (20.13-21.64 g/L). The SSF process, with the highest ethanol productivity (0.291 g/L/h), was chosen to study the effect of solid loading at 40 degrees C. A CRC level of 12.5\% (w/v) via fed-batch SSF resulted in the highest ethanol concentrations of 38.23 g/L. Thereafter, bioethanol production via fed-batch SSF with 12.5\% (w/v) CRC was performed in 5-L bioreactor. The maximum ethanol concentration and ethanol productivity values were 31.96 g/L and 0.222 g/L/h, respectively. The thermotolerant S. cerevisiae TC-5 is promising yeast for bioethanol production under elevated temperatures via SSF and the use of second-generation substrates.
The roles of water and aluminum sulfate (Al-2(SO4)(3)) in one-step selective catalytic transformation of hemicellulose in corn stover were investigated. At 130 degrees C, 90.2 wt\% hemicellulose contained was selectively dissolved and further converted to 85.1 wt\% xylose in the presence of Al-2(SO4)(3), while keeping cellulose (92.1 wt\%) and lignin (88.4 wt\%) insignificantly converted. The hemicellulose hydrolysate could be further transformed to lactic acid with the yield of 82.2 wt\% using Lactobacillus plantarum via fermentation. H2O formed hydrogen bonds with the intermolecular linkages connecting hemicellulose with cellulose and lignin in corn stover, which was helpful to dissolve hemicellulose. The hydrolysis of Al-2(SO4)(3) formed H+ (Brunsted acid), which enhanced selectively the conversion of hemicellulose to xylose. While the active Lewis acid {[
A bacterial consortium with the ability to degrade methyl parathion and p-nitrophenol, using these compounds as the only carbon source, was obtained by selective enrichment in a medium with methyl parathion. Samples were taken from Moravia, Medellin; an area that is highly contaminated, owing to the fact that it was used as a garbage dump from 1974 to 1982. Acinetobacter sp, Pseudomonas putida, Bacillus sp, Pseudomonas aeruginosa Citrobacter freundii, Stenotrophomonas sp, Flavobacterium sp, Proteus vulgaris, Pseudomonas sp, Acinetobacter sp, Klebsiella sp and Proteus sp were the microorganisms identified within the consortium. In culture, the consortium was able to degrade 150 mgL-1 of methyl-parathion and p-nitrophenol in 120 h, but after adding glucose or peptone to the culture, the time of degradation decreased to 24 h. In soil, the consortium was also able to degrade 150 mgL-1 of methyl parathion in 120 h at different depths and also managed to decrease the toxicity.
The utilization from biomass feedstocks to fabricate the advanced nanomaterials has greatly attracted a great interest due to their low cost and sustainability. This work aimed to explore a simple way to prepare cellulose nanofibers using water-based approach via mechanical defibrillation. Cellulose fibers were first extracted from water hyacinth towards chemical treatments and then mechanically disintegrated as a function of defibrillation cycles. The morphologies, thermal stabilities, physical properties, and rheological characteristics of the micro- and nanofibers were demonstrated. It was found that the obtained nanofibers having a diameter of 5-50 nm and were successfully prepared within 10 defibrillation cycles. Even though longer defibrillation cycles greatly provided higher water retention value and specific surface area, a gradual decrease in crystallinity index, thermal degradation temperatures, and degree of polymerization was also observed. Based on the rheological properties, the storage modulus and steady viscosity of the as-prepared nanofibers suspension increased significantly as a function of defibrillation, resulting in a gel-like structure with a shear-thinning behavior. Additionally, the rheological parameters of the obtained nanofibers estimated using a Herschel-Bulkley model were more accurate than that estimated using a Bingham-Plastic model. The obtained nanofibers could be used as a prime candidate for many potential applications. (C) 2019 Elsevier B.V. All rights reserved.
Oil palm empty fruit bunches (EFB) are a lignocellulosic by product generated by palm oil mills. Delignified EFB fiber is a potential source of inexpensive hemicellulose, a substrate that is easily hydrolyzed to sugars for use in diverse biotechnological processes. The conditions for maximized selective removal of lignin from EFB fiber via separate treatments with alkaline peroxide and peracetic acid, were established such that the loss of hemicellulose was kept to a minimum. The amount of a reagent used in delignification, the temperature and the length of treatment, were optimized using a combination of Box Behnken experimental design and the response surface method. Treatments with peracetic acid always left behind more hemicellulose and removed more lignin compared with the treatments involving alkaline peroxide. Under the best conditions (20 cm(3) peracetic acid per g EFB, 35 degrees C, reaction time of 9 h), hemicellulose, cellulose and acid insoluble lignin constituted (dry weight basis) nearly 36\%, 47\% and similar to 16\%, respectively, of the treated acetone-washed extractive-free EFB fiber. Approximately 53\% of the lignin was removed, but nearly all the hemicellulose was retained. (C) 2014 Elsevier Ltd. All rights reserved.
In the corn crop industry, of all the biomass produced, about 80\% are residues. The so-called corn fibers, one of the most important residues of the corn processing industry, represent about 9\% of the corn kernel weight, being a low value material that could, potentially, be used for making higher added value products. This work aimed to extract the hemicelluloses present in the corn fiber via alkaline extraction, with their subsequent functionalization for production of carboxymethyl xylans in mild conditions. The corn fibers were characterized for their contents of carbohydrates, lignin, extractives, total uronic acids, acetyl groups, and ash. Their arabinoxylans were extracted by 2-18\% (w/v) sodium hydroxide at room temperature, for 5h at 10\% consistency, precipitated with ethanol, washed and then vacuum dried. The resulting extract was characterized by FT-IR, viscosity, arabinoxylan content and purity. It was demonstrated that CCE treatment provides a high purity and little degraded xylan, but the extraction yields are relatively low, in the range of 4.0-23.9\% wt/wt depending upon extraction conditions. The use of corn fiber arabinoxylans to obtain hemicellulosic derivatives through chemical modification reactions was also evaluated. The arabinoxylans were derivatized by carboxymethylation with sodium monochloroacetate in a 2-propanol alkaline medium using different proportions of alcohol and alkali. The product carboxymethyl xylan was characterized by degree of substitution, FT-IR, DSC, and yield, and showed high degree of substitution, yield and enthalpy of fusion. This work proved the feasibility of producing hemicellulosic derivatives from corn fibers, which excludes the use of extreme conditions of solvents and temperature.
Parthenium hysterophorus, the world's one of the most dangerous weeds, was used in the present study for the extraction of cellulose. The extraction of cellulose from Parthenium hysterophorus was optimized using Plackett Burman (P-B) Design and Response Surface Methodology (RSM) involving Box-Behnken Design (BBD). The extracted cellulose was obtained with a maximum yield of 36.43\% using 2.5\% (wt/vol) of acid, 5.9\% (wt/vol) of alkali and 2.6\% (wt/vol) of chlorination treatment. The yield of the cellulose found to be 36.43\% which was 74\% higher than the pre-optimized value of 21\%. SEM micrographs of the extracted cellulose showed cleaner surface and fibrillar morphology compared with Parthenium biomass. The functional groups of extracted cellulose were characterized by FTIR. The amorphous and crystalline nature of the extracted cellulose was determined by XRD and the Crystallinity Index was calculated as similar to 55.28. The thermal stability of the extracted cellulose was better than the commercial cellulose and it was stable up to the temperature close to 350 degrees C. The extracted cellulose was used to synthesize cellulose acetate and was used further for the preparation of bioplastic film. The prepared bioplastic was highly resistant to salt and 10\% sulfuric acid, but was labile in the presence of alkali. The produced bioplastic film exhibited tensile strength of 10.8 +/- 0.15 MPa, 2.86 +/- 0.28\% elongation at break and Young's modulus of 153.61 +/- 0.08 MPa. Therefore, Parthenium hysterophorus can be a potential source for the preparation of bioplastic and the produced bioplastic can be potentially applied in food, medicine and packaging industries.
This study investigated the decomposition behavior of bamboo under hydrothermal and hydrolysis conditions with H2O/CO2 in a semicontinuous-flow reactor at 9.8 MPa. At 255 degrees C, with and without CO2, xylan in bamboo completely decomposed into xylo-oligosaccharide (XOD). The yield of glucan degradation products with CO2 was significantly higher compared with that under the hydrothermal reaction (25.7 vs 14.9 wt \%, respectively). The reaction rate of glucan decomposition with CO2 was slightly higher than the rate of hydrothermal reaction (k(H2O/CO2)/k(H2O) = 1.3). Increasing the fluid velocity of the hydrothermal reaction (3-10 mL/min) significantly accelerated the solubilization rate, but the ultimate yield of the soluble fraction was unchanged. The ultimate yield of the soluble fraction was slightly affected by physical effects. Hydrolysis with CO2 under severe conditions exhibited effective degradation of glucan. The catalytic activity of the H2O/CO2 system under hydrolysis can be explained by the system's chemical effect.
In this paper the lignin gasification by using water in supercritical was studied. The employed lignin was produced via steam explosion of Arundo Donax after alkaline extraction and filtration. The lignin, with a total solid content of about 4 wt\% in a solution of sodium hydroxide which confers to the solution a pH of about 11, was fed in a continuous PFR bench scale reactor able to operate at supercritical water conditions. The experiments were carried out at 550 degrees C and 250 bar by varying the feed flow rate from 10 mL/min to 60 mL/min in order to understand the effect of the residence time on the liquid and solid phases in terms of volume composition, liquid phase composition, carbon and global gasification efficiency. The main results showed that by using lignin after alkaline extraction, syngas with a higher heating value (HHV) greater than 40 MJ/kg without CO2, mainly composed by hydrogen and methane, was obtained. At the same time, in the liquid phase the presence of some compounds, such as glucose, syringaldehyde, formic acid, acetic acid and xylose, was revealed, and all these species are included in the main building block group for the green chemistry or for the development of bioprocess for high added value intermedia production.
This study is aimed at achieving the optimum conditions of hydrothermal treatment and acetylation of Populus fiber to improve its oil sorption capacity (OSC) in an oil-water mixture. The characteristics of the hydrolyzed and acetylated fibers were comparatively investigated by FT-IR, CP-MAS C-13-NMR, SEM and TGA. The optimum conditions of the hydrothermal treatment and acetylation were obtained at 170 degrees C for 1 h and 120 degrees C for 2 h, respectively. The maximum OSC of the hydrolyzed fiber (16.78 g/g) was slightly lower than that of the acetylated fiber (21.57 g/g), but they were both higher than the maximum OSC of the unmodified fiber (3.94 g/g). In addition, acetylation after hydrothermal treatment for the Populus fiber was unnecessary as the increment of the maximum OSC was only 3.53 g/g. The hydrolyzed and the acetylated Populus fibers both displayed a lumen orifice enabling a high oil entrapment. The thermal stability of the modified fibers was shown to be increased in comparison with that of the raw fiber. The hydrothermal treatment offers a new approach to prepare lignocellulosic oil sorbent.
Chemical modification is the most important means to obtain novel biopolymers and biomaterials from the abundant biomacromolecules. In this paper, hemicellulosic succinate, which is very important biomacromolecule for the preparation of functional materials, was homogeneously prepared in 1-butyl-3-methylimidazolium chloride ({[
Brewer's spent grain components (cellulose, hemicellulose and lignin) were fractionated in a two-step chemical pretreatment process using dilute sulfuric acid and sodium hydroxide solutions. The cellulose pulp produced was hydrolyzed with a cellulolytic complex, Celluclast 1.5 L, at 45 degrees C to convert the cellulose into glucose. Several conditions were examined: agitation speed (100, 150 and 200 rpm), enzyme loading (5, 25 and 45 FPU/g substrate), and substrate concentration (2, 5 and 8\% w/v), according to a 2(3) full factorial design aiming to maximize the glucose yield. The obtained results were interpreted by analysis of variance and response surface methodology. The optimal conditions for enzymatic hydrolysis of brewer's spent grain were identified as 100 rpm, 45 FPU/g and 2\% w/v substrate. Under these conditions, a glucose yield of 93.1\% and a cellulose conversion (into glucose and cellobiose) of 99.4\% was achieved. The easiness of glucose release from BSG makes this substrate a raw material with great potential to be used in bioconversion processes.
In order to reduce the CO2 produced from the combustion of fossil fuel, bioethanol produced from biomass can serve as an alternative fuel. Rice husk, known as a widely available lignocellulosic biomass and one of the most prominent agricultural residues would be a suitable alternative. For producing bioethanol and improving enzymatic hydrolysis, this study successfully pretreated rice husk using ammonium carbonate solution. The maximum glucan digestibility yield of the pretreated rice husk was 67.7\% and 65.7\% respectively, with 20\% and 25\% ammonium carbonate solution with 10 FPU/g glucan loading of a commercial cellulase enzyme for 72 h 10.61 g/L. ethanol concentration was achieved from 20\% ammonium carbonate pretreated rice husk in the simultaneous saccharification and fermentation (SSF) process under anaerobic condition at 37 degrees C with Saccharomyces cerevisiae for 3 days. (C) 2017 Elsevier B.V. All rights reserved.
Improvements in enzymatic hydrolysis for production of bioethanol from sustainable biomass are necessary in order to reduce enzyme requirements and the overall processing times. Conventional techniques for pretreatment of lignocelluloses are quite costly, time-consuming, and also require substantial downstream processing. Ultrasound can be effectively used to improve the hydrolysis process by reducing the structural rigidity of lignocellulose and by eliminating the mass-transfer resistances, which can contribute to increase in the product yield with reduced processing time and enzyme consumption. The present work initially presents an overview of different pretreatment methods involved in the enzymatic hydrolysis of lignocellulosic biomass highlighting its limitations. Expected mechanism of intensification due to the use of ultrasound has been discussed, also giving recommendations for optimum operating conditions. An overview of the different studies related to enzymatic hydrolysis using ultrasound for bioethanol production has been presented, along with discussion related to types of sonochemical reactors and scale-up aspects. Possible combination of sonication by coupling with traditional pretreatment processes has also been discussed. Overall, it appears that ultrasonic irradiations can be effectively used for the intensification of the enzymatic hydrolysis process for efficient bioethanol production.
The commercial production of bioethanol from lignocellulosic biomass is challenged by the repression of cell growth and compromised fermentation conditions. However, employing Saccharomyces cerevisiae is an economically feasible process resulting in the effective conversion of fermentable sugars to bioethanol. S. cerevisiae's high productive feature is contributed by robust alcohol dehydrogenase and the ability to tolerate various stresses during the fermentation process. The present review employs various bioinformatics pipeline to assess the structural insights of ADH and interaction among the tolerance genes. Docking of S. cerevisiae's ADH interaction shows the high binding affinity of - 2.81 Kcal/mol with acetaldehyde contributed by four zinc fingers. In inhibitor tolerance capacity of S. cerevisiae was explored. The STRING platform sheds light on the mechanism and interaction of ASR1 and other stress-responsive elements playing a pivotal role in ethanol tolerance. The stress-responsive genes such as HSPs and MSN2/4 provide balanced physiology under various stress conditions. The present review unravels the complex mechanism behind the inhibitor and ethanol tolerance, directing to several bottlenecks for the improvisation of S. cerevisiae's performance.
In this study, a biogenic method is reported for the fabrication of gold nanoparticles (Au NPs) using Saccharum officinarum L. (SOL) as a dual performer, both as a reducing and stabilizing agent. The method used in this study is efficient, economic, and eco-friendly for the fabrication of noble metals NPs. The peroxidase mimicking activity of the SOL capped Au NPs (S-Au NPs) was evaluated using o-dianisidine (ODA) as a substrate and Au NPs as an enzyme mimic. A color change from colorless to brown was observed for the oxidized ODA product with a UV-visible peak at 420 nm in the presence of Au NPs and H2O2. An enhanced enzyme activity of 95.7\% was observed for the Au NPs. Kinetic activity was evaluated by Michaelis-Menten plot, and the k(m) and V-max values were found to be 0.62 mM and 0.20 min(-1), respectively. The detailed probable mechanism of Au NPs synthesis and the oxidation of ODA with S-Au NPs were also discussed. This novel synthetic method provides a sustainable route for the synthesis of diverse NPs in future and various biogenic NPs can be explored as an efficient nanoenzyme in the drug delivery and sensing field.
Spartina anglica, a plant that controls coastal erosion, is widely distributed throughout the world and is rich in cellulose, hemicellulose, and lignin. The hemicellulose from Spartina anglica can be extracted and hydrolyzed into monosaccharides and xylooligosaccha rides under acid or enzymatic digestion conditions. In this study, an effective PMP(1-phenyl-3-methyl-5-pyrazolone)-derivatized HPLC (High performance liquid chromatography) method was developed for monitoring monosaccharides and xylooligosaccharides of Spartina anglica. With phosphate buffer (0.04 M, pH 8.06) as mobile phase A, and acetonitrile as mobile phase B, in which the elution gradient was set as A:B/79:21, the monosaccharides (glucose, xylose and arabinose) and xylooligosaccharides (xylobiose, xylotriose, xylotetraose, xylopentaose, xylohexaose) could be separated completely using the C18 column. This provides an economical, rapid, and efficient method for process monitoring in the bioconversion of Spartina anglica.
One way to reduce the use of wood resources and simultaneously to manage wastes in the form of forest and agricultural biomass, as well as biomass originating from the food processing industry, is to use those wastes in particleboard production as an alternative raw material to wood chips. This article highlights the potential of woody biomass from non-forest sources. Based on a review of the current scientific literature, an attempt is made to identify the raw materials with the greatest potential, considering their availability and the quality of boards made from them. Suggestions are also made regarding the search for new raw materials, based on their production potential.
Maize stalk has been identified as a potential biomass for bio-ethanol production and has always been handled as a single biomass, though it is a heterogeneous mix of pith and rind fractions. Physical and chemical assays were conducted on each biomass fractions and compared to the single biomass for suitability for ethanol production. Moisture content and specific gravity including percentage composition of the fractions in the biomass were determined. Fibre characterisation was achieved using equal volumes of glacial acetic acid and hydrogen peroxide whilst chemical analyses which included compositional and ultimate analyses were determined using various standard procedures for each tests. The results of specific gravity obtained showed that the whole maize stalk has a specific gravity of 0.38, with pith and rind having values of 0.17 and 0.85, respectively. Fibre morphology is similar for both pith and rind fractions, and photomicrograph showed significantly less fibres in pith than the rind. Compositional analysis revealed the presence of 36.7\% and 46.4\% cellulose, 26.3\% and 18.2\% hemicellulose and 18.1\% and 21.2\% lignin for pith and rind fractions, respectively. The higher cellulose content of the maize stalk rind makes it a preferred fraction for biosynthesis.
The production of Melaleuca leucadendron essential oil generates a lot of solid waste, since only under 2\% take it out as the oil product. The solid waste contains cellulose as an important content which can be isolated by alkaline treatment of sodium hydroxide (NaOH). In this project, optimization of alkaline treatment of M. leucadendron twigs (MLT) waste was studied in order to obtain optimum isolated cellulose. The experiments were conducted at atmospheric pressure and boiling temperature. The 33 Box-Behnken design (BBD) was used to evaluate the effects of treatment time, solid loading and NaOH concentration. Quadratic model evaluation showed that the model is a prospective to describe the effects of the variables (R-2= 0.8994, p<0.05). The significant variables were found in linear term of NaOH concentration and quadratic term of treatment time. The optimum result of the experimental variables range was predicted in treatment time, solid loading and NaOH concentrations of 60 minutes, 10\%, and 1.83\% respectively. In conclusion, BBD is appropriate to optimize cellulose isolation process of MLT.
An experimental study on the acid hydrolysis of Cenchrus ciliaris particles was conducted. Input variables included particle size of the raw material (<0.053 mm and 0.16 mm), sulfuric acid concentration (0.05 and 0.15 M), and reaction temperature (120150 degrees C). Output variables included the concentrations of xylose, glucose, arabinose, and furfural in the aqueous solution. Five chemical reactions involving the hydrolysis of the Cenchrus ciliaris particles and the decomposition of the monosaccharides were proposed, and a pseudohomogeneous model consisting of five ordinary differential equations was developed. By means of numerical techniques, the values of the parameters of the Arrhenius equation for all chemical reactions were determined. Good agreement between the model predictions and the experimental data was obtained. The hemicellulose in the Cenchrus ciliaris particles was represented by an empirical formula containing 55 units of xylan, 25 units of glucan, and 19 units of arabinan oligomers.
UTILIZATION OF CELLULOSE ACETATE PRODUCED FROM MANGO SEED CELLULOSE AS MATRIX FOR PRODUCTION OF MICROPARTICLES SYSTEMS. Cellulose acetate produced from mango seed fibers cellulose was used as a matrix for preparation of microparticles empty and load with acetaminophen (Paracetamol) in order to evaluate the incorporation of an active agent during the formation of microparticles. The microparticles are characterized by Fourier Transformed Infrared spectroscopy (FTIR), Differential Scanning Calorimetry (DSC) and Scanning Electron Microscopy (SEM). The incorporation of paracetamol can be confirmed by the change in value of glass transition temperature (Tg). The formation of microparticles spherical was observed by SEM and showed an average diameter of 1.010 and 0.950 mu m for empty and load microparticles respectively.
The effects of the nitrogen source and buffers used in butanol production with Clostridium beijerinckii TISTR 1461 from sweet sorghum stem juice (SSJ) containing 60 g/L of total sugar were first studied in this paper. Among the various nitrogen sources (dried spent yeast, urea, ammonium acetate, ammonium sulfate), urea was found to be the most suitable for butanol production. SSJ supplemented with urea (0.64 g/L) and cocktail buffers (KH2PO4, 0.5 g/L; K2HPO4, 0.5 g/L; ammonium acetate, 2.2 g/L) gave the highest butanol concentration (P-B, 10.13 g/L). Then, the capability of immobilized C. beijerinckii TISTR 1461 cells for butanol fermentation was investigated. Two residual waste materials were examined as immobilized cell carriers. Bamboo chopstick pieces were more appropriate as carriers for cell immobilization than cigarette filter tips. The P-B value of the immobilized cells on the bamboo chopstick pieces was similar to 13\% higher than that on the cigarette filter tips. Using the response surface methodology (RSM), 1.9 cm bamboo chopstick pieces with a carrier loading of 1:32 (w/v) were the optimum conditions for cell immobilization for butanol production. Under these conditions, the P-B value was 11.62 g/L. To improve the butanol production efficiency, a gas stripping system (GS) was connected to the fermenter. It was found that the P-B (14.02 g/L) and butanol productivity (Q(B), 0.29 g/L.h) values improved by similar to 21\% compared to butanol fermentation using no gas stripping.
Coriolus hirsutus pellets grown in a melanoidin-containing medium produced extracellular H2O2 up to 43 mu M. However, nonenzymatic decolorization of melanoidin by H2O2, which has been previously reported, seemed very little in the fungal culture. The culture fluid contained two extracellular peroxidases, a manganese-independent peroxidase (MIP) and manganese peroxidase (MnP). Since both MIP and MnP showed melanoidin-decolorizing activities in the presence of H2O2, it was concluded that melanoidin decolorization in the C. hirsutus culture involved the production of extracellular H2O2 and the peroxidases.
In the present study, adsorption isotherms, kinetics and thermodynamics of fermentation inhibitors generated during the acid hydrolysis of corncob were investigated using activated charcoal (0.5-2.0\% w/v) as the adsorbent. The results indicated that lower pH and lower temperature favor the adsorption of both furans and phenolics. The adsorption kinetic regimes were found more favorable in pseudo second order kinetics than pseudo first order kinetics. The experimental values were in good correlation with the predicted values with a regression coefficient (R2) value of more than 0.99. Moreover, the negative values of enthalpy (Delta H), and free energy (Delta G) indicated that the adsorption process was spontaneous in nature and exothermic. The detoxified corncob hydrolysate on its assessment for fermentability revealed the production of 4.8 g/L and 4.3 g/L xylitol from Candida tropicalis ITCC 1830 and C. tropicalis MTCC 9038. The activated charcoal adsorption has shown differential adsorption capacity and isotherms on various inhibitors under different conditions. Hence using the optimum conditions the process efficiency can be improved to make the whole process cost competitive.
Tequila vinasses (TVs) generated during Tequila production are brown liquid residues rich in nutrients. The nutrient content of agro-industrial effluents represents an excellent resource to support low-cost biomass production of microalgae; nonetheless, it is crucial to select the suitable microalgal strain to attain the highest biomass production in each residue used. In this study, biomass production, CO2 fixation from biogas, and cell compound accumulation by Chlorella vulgaris U162, Chlorella sp., Scenedesmus obliquus U169, and Scenedesmus sp. using biodigested and filtered TVs as culture medium were evaluated and compared with the conventional microalgal culture media, C30, BG-11, Bold 3N, and Bristol. The four microalgae evaluated attained the highest biomass production and CO2 fixation rate cultured in both residues, accumulating mainly carbohydrates and proteins although the most appropriate microalga to be cultured in TVs was Chlorella sp., recording 2.30 g L-1. Moreover, the nutrient ratio of filtered TVs was ideal to support biomass production while biodigested TVs need to be supplemented with nitrogen. Overall, these results demonstrated that tequila vinasses are an excellent resource to support high and quick biomass production of microalgae, which can be used to obtain biofuels as ethanol, biogas, and supplement food depicting an extra benefit during the appropriate disposal of this residue.
Growth in population and thereby increased industrialization to meet its requirement, has elevated significantly the demand for energy resources. Depletion of fossil fuel and environmental sustainability issues encouraged the exploration of alternative renewable eco-friendly fuel resources. Among major alternative fuels, bio-ethanol produced from lignocellulosic biomass is the most popular one. Lignocellulosic biomass is the most abundant renewable resource which is ubiquitous on our planet. All the plant biomass is lignocellulosic which is composed of cellulose, hemicellulose and lignin, intricately linked to each other. Filamentous fungi are known to secrete a plethora of biomass hydrolyzing enzymes. Mostly these enzymes are inducible, hence the fungi secrete them economically which causes challenges in their hyperproduction. Biomass's complicated structure also throws challenges for which pre-treatments of biomass are necessary to make the biomass amorphous to be accessible for the enzymes to act on it. The enzymatic hydrolysis of biomass is the most sustainable way for fermentable sugar generation to convert into ethanol. To have sufficient ethanol concentration in the broth for efficient distillation, high solid loading similar to<20\% of biomass is desirable and is the crux of the whole technology. High solid loading offers several benefits including a high concentration of sugars in broth, low equipment sizing, saving cost on infrastructure, etc. Along with the benefits, several challenges also emerged simultaneously, like issues of mass transfer, low reaction rate due to water constrains in, high inhibitor concentration, non-productive binding of enzyme lignin, etc. This article will give an insight into the challenges for cellulase action on cellulosic biomass at a high solid loading of biomass and its probable solutions.
To improve the enzymatic saccharification of lignocellulosic biomass, a mixture of ethylene glycol-HClO4-water (88.8:1.2:10, w/w/w) was used for pretreating corn stover in this study. After the optimization in oil-bath system, the optimum pretreatment temperature and time were 130 A degrees C and 30 min, respectively. After the saccharification of 10 g/L pretreated corn stover for 48 h, the saccharification rate was obtained in the yield of 77.4 \%. To decrease pretreatment temperature and shorten pretreatment time, ethylene glycol-HClO4-water (88.8:1.2:10, w/w/w) media under microwave irradiation was employed to pretreat corn stover effectively at 100 A degrees C and 200 W for 5 min. Finally, the recovered hydrolyzates containing glucose obtained from the enzymatic hydrolysis of pretreated corn stovers could be fermented into ethanol efficiently. These results would be helpful for developing a cost-effective pretreatment combined with enzymatic saccharification of cellulosic materials for the production of lignocellulosic ethanol.
Nanocellulosic materials, either as cellulose nanofibrils (CNF) or cellulose nanocrystals (CNC), have a wide range of potential applications in different industrial sectors, due to their renewable nature and remarkable properties. Here, a sustainable and environmentally friendly method to obtain nanocellulose was evaluated using hydrolysis with citric acid, an organic acid that can be obtained as a biorefinery product. This approach resulted in a single-step extraction of nanocellulose, with carboxyl functionalization of the surface varying according to hydrolysis reaction times from 1.5 to 6 h, at 120 degrees C, as evidenced using NMR to measure the degree of substitution. The charged surface groups of CNC and CNF resulted in improved colloidal stability, with zeta-potential values from -36 to -48 mV. Both CNC and CNF extracted using different reaction times were thermally stable, but the increase of carboxyl groups reduced the degradation temperature. Techno-economic analysis (TEA) showed that the cost of citric acid had the greatest influence on the minimum product selling price (MPSP) of the nanocellulose, indicating that the production of citric acid within the biorefinery could be an interesting way to make this approach feasible.
In this study, tobacco stalk (TS), the solid residue from tobacco industry, was utilized as the raw material for the production of bioethanol through combining processes of alkaline pretreatment or acid-catalyzed (AC) steam pretreatment followed by enzymatic hydrolysis and fermentation. The results indicate that both the two pretreatment strategies could efficiently improve the enzymatic digestibility of TS. Compared to alkaline pretreatment, AC steam pretreatment solubilized more xylan into the liquid phase while preserving more lignin in the pretreated solid substrate. Following enzymatic saccharification of whole pretreated materials from two pretreatment methods at a modest enzyme loading of 15 mg protein/g glucan, the slurry from alkaline pretreatment achieved a slightly higher total monomeric sugar yields than that of AC steam pretreatment. The sugars in the obtained enzymatic hydrolysates from both the two pretreatment technologies showed good sugar-to-ethanol conversion during fermentation with Saccharomyces cerevisiae Lg8-1 strain. The overall mass balances showed that yields of ethanol were 2.75 and 2.69 kg per 10 kg of untreated TS for alkaline and AC steam pretreatments, respectively.
Bioethanol production from lignocellulosic biomass is very efficient when using a consolidated bioprocessing (CBP) system. However, the optimum temperature conditions for the hydrolysis of cellulosic materials might not be the same as the optimum sugar fermentation temperature. This study investigated the effect of temperature on hydrolysis and bioethanol production from vetiver leaves (Vetiveria zizanioides L. Nash) as cellulosic material. The hydrolysis of pretreated vetiver leaves was done using a crude hydrolytic enzyme extracted from N. intermedia. Hydrolysis proceeded efficiently at 50 degrees C, obtaining the highest enzyme activity of 141 U/g. On the other hand, the bioethanol fermentation from vetiver leaves was performed in a CBP batch mode system which was carried out through two stages of fermentation in the same bioreactor. In the first stage, the N. intermedia was grown under micro-aerobic conditions at room temperature for 48 h. The cultivation was continued in the second stage by setting the fermentation temperature with various fermentation temperatures. The optimum temperature with the highest bioethanol concentration of 6905 mg/L was 45 degrees C. The kinetic parameters were also validated and obtained based on the growth model simulation.
Within the strategies of substitution of energy from fossil fuels by renewable energies, the research is based on second-generation ethanol production (2G ethanol). One of the raw materials considered for this is residual biomass of the coffee industry, being the subject of study here. The cellulose contained in the coffee husk (coffee husk or coffee skin or coffee exocarp or pericarp) was maximized using pretreatment processes. In dilute acid hydrolysis (DAH), using a fixed 1:6 w:v solid to liquid ratio (SLR), process times (35, 45, 55 min) and H(2)SO(4)concentrations (3, 4, 5\% v/v) were evaluated, achieving 53.63\% hemicellulose removal. A delignification process resulted in 58.82\% lignin removal, evaluating the effect of process times (30, 35, 40 h) and SLR (1:8, 1:10, 1:12 w:v) at a fixed concentration of 8\% v/v H2O2. A 115.59 g/L glucose concentration was obtained with an interaction of fixed concentrations of 4-6\% w/w Cellic CTec3 enzyme and 6:1 to 1:12 v:w SLR. The fermentation process considered the composition variation of the culture medium (enriched culture C1 and non-enriched culture C2), generating ethanol at 48.19 and 29.02 g/L concentrations, respectively. Fermentation efficiency (eta(f)) was improved from 21.99 to 81.74\% with the addition of inorganic nutrients (KH2PO4, (NH4)(2)SO4, and MgSO4 center dot 7H(2)O). These results confirmed that the optimization of the pretreatments in coffee husk waste favored the cellulose production and facilitated the enzymatic process to produce a high glucose concentration, revealing these residues as a carbon source promising for second-generation ethanol production.
Varying levels of high pressure homogenization (HPH) were applied to disintegrate bacterial nanofibrillated cellulose (BNFC) from bacterial cellulose (BC). HPH was considered as a simple, non-toxic and highly efficient physical method for nanofibrillated cellulose extraction. The blended BC passed through chambers at high pressures of 68, 138 and 207 MPa for 30 cycles. The particle size confirmed disintegration of the BC network fibers to bundles of BNFC and the atomic force microscopy images showed the decreased diameter of individual BNFC in the range 36-67 nm. Fourier transform infrared spectroscopy measurement indicated there were no change in the chemical functional groups of the BNFC compared with BC. The decreased crystallinity index and crystallite size of BNFC with increased pressure confirmed the effect of HPH on the BNFC. Nevertheless, BNFC at 207 MPa had the lowest thermal stability due to having the highest surface area, which resulted in the minimum nanofiber diameter.
Norway spruce (Picea abies) is an industrially important softwood species available in northern Europe and can be used to produce bio-methane after proper pretreatment to overcome its recalcitrant complex structure. Hot water extraction (HWE) pretreatment at two different conditions (170 degrees C for 90 min (severity 4.02) and 140 degrees C for 300 min (severity 3.65)) was applied to extract hemicellulosic sugars from Norway spruce for thermophilic anaerobic digestion (AD) of the hydrolysate. The methane yield of hydrolysate prepared at the lower pretreatment severity was found to be 189 NmL/gCOD compared to 162 NmL/gCOD after the higher pretreatment severity suggesting higher pretreatment severity hampers the methane yield due to the presence of inhibitors formed due to sugars and lignin degradation and soluble lignin, extracted partially along with hemicellulosic sugars. Synthetic hydrolysates simulating real hydrolysates (H170syn and H140syn) had improved methane yield of 285 NmL/gCOD and 295 NmL/gCOD, respectively in the absence of both the inhibitors and soluble lignin. An effect of organic loadings (OLs) on the methane yield was observed with a negative correlation between OL and methane yield. The maximum methane yield was 290 NmL/gCOD for hydrolysate pretreated at 140 degrees C compared to 195 NmL/gCOD for hydrolyate pretreated at 170 degrees C, both at the lowest OL of 6 gCOD/L. Therefore, both pretreatment conditions and OL need to be considered for efficient methane production from extracted hydrolysate. Such substrates can be utilized in continuous flow industrial AD with well-adapted cultures with stable organic loading rates.
The full use of biomass in future biorefineries has stimulated studies on utilization of lignin from agricultural crops, such as coffee husk, a major residue from coffee processing. This study focuses on characterizing the lignin obtained from coffee husk and its further wet oxidation products as a function of alkali loading, temperature and residence time. The lignin fraction after diluted acid and alkali pretreatments is composed primarily of p-hydroxylphenyl units (>= 49\%), with fewer guaiacyl and syringyl units. Linkages appear to be mainly beta-O-4 ether linkages. Thermal degradation of pretreated lignin during wet oxidation occurred in two stages. Carboxylic acids were the main degradation product. Due to the condensed structure of this lignin, relatively low yields of aromatic aldehydes were achieved, except with temperatures over 210 degrees C, 5 min residence time and 11.7 wt\% NaOH. Optimization of the pretreatment and oxidation parameters are important to maximizing yield of high-value bioproducts from lignin.
A glycerol-organosolv process can be a good alternative for Eucalyptus wood fractionation into its main compounds, improving the enzymatic saccharification of the cellulose. A study of process variables - glycerol-water percent content, temperature, and process time - was carried out using a Box-Behnken experimental design. The cellulose obtained from pretreated solids was recovered almost quantitatively, leading to a solid with a high percentage of cellulose (77 g/100 g of pretreated solid), low lignin content (9 g/100 g of pretreated solid), and 18\% of residual hemicellulose in the solid at 200 degrees C, 56\% of glycerol-ater and 69 min. The enzymatic saccharification was enhanced achieving 98\% cellulose-to-glucose conversion (under conditions: liquid to solid ratio 20 g/g and enzyme loading 20 FPU/g of solid). This study contributes to the improvement of biomass fractionation by exploring an eco-friendly treatment which allows for almost complete wood fractionation into constituents an high levels of glucose recovery available for subsequent yeast fermentation to bioethanol.
Climatic changes and the growing population call for innovative solutions that are able to produce biochemicals by adopting environmentally sustainable procedures. The biorefinery concept meets this requirement. However, one of the main drawbacks of biorefineries is represented by the feedstocks' pretreatment. Lately, scientific research has focused on non-thermal plasma, which is an innovative and sustainable pretreatment that is able to obtain a high sugar concentration. In the present review, literature related to the use of non-thermal plasma for the production of fermentable sugar have been collected. In particular, its sugar extraction, time, and energy consumption have been compared with those of traditional biomass pretreatments. As reported, on one hand, this emerging technology is characterized by low costs and no waste production; on the other hand, the reactor's configuration must be optimized to reduce time and energy demand.
The present study was aimed to evaluate the ability of Meyerozyma guilliermondii P14 to produce bioethanol from pretreated biomass of giant reed (Arundo donax). The wild yeast was isolated from its natural habitat and identified by phylogenetic analysis. Arundo donax biomass was sequentially pretreated by acid and alkali treatments to break the recalcitrant structure. The pretreated biomass was analysed by FTIR spectroscopy and scanning electron microscopy to observe the structural changes in the biomass. Pretreated biomass was then enzymatically saccharified, and the resultant broth was used to produce ethanol by M. guilliermondii P14. The fermentation parameters such as pH, temperature, composition of media, and agitation rate were optimized prior to saccharified broth-based fermentations. The results of this study revealed that the dual pretreatment of biomass could make 90.56\% cellulose accessible for enzymatic attack. Subsequently, saccharification of pretreated biomass with two enzyme variants resulted in conversion efficiency of 85-87\%. Fermentation of saccharified broth resulted in 32.89 g/L final ethanol concentration at 72 h. This has corresponded to 0.48 g/g of ethanol yield and 0.456 g/L/h volumetric productivity. M. guilliermondii is known to utilize both pentose and hexose sugars unlike Saccharomyces cerevisiae which makes it a major player in cellulosic ethanol production. This study provides a significant evidence to the information pool of second-generation bioethanol production from unconventional glucose fermenting yeasts.
Xylose residue (XR), the abundant industrial residue from commercial xylose production, was delignified using alkali as a substrate for ethanol production via simultaneous saccharification and fermentation (SSF). It was found that pretreatment with 1.5\% (w/v) NaOH at 140 degrees C for 1.5 h was optimal for delignification efficiency (72.2\%) and low cellulose loss (7.1\%). The physical changes in samples after alkaline pretreatment were characterized for crystallinity and imaged using scanning electron microscopy (SEM), which demonstrated that the surface of samples became coarser with lignin removal. There were rather significant changes in cellulose crystallinity. The widespread accessibility of cellulose in XR favored enzymatic hydrolysis and achieved considerable bioconversion (98.8\% with 15 PFU/g substrate). The maximum for ethanol concentration using SSF bioconversion reached 16.3 g/L, which was about four times more than that of the untreated sample. XR treated using the processes of alkaline pretreatment and SSF was an excellent substrate for bioconversion.
The conversion of lignocellulosic biomass into bioethanol remains a challenging process due to the recalcitrant structure of lignocellulose. The presence of the sturdy lignin protective sheath, complex structure, and partial crystallinity of cellulose often reduces the enzymatic susceptibility of lignocellulosic biomass. Therefore, pretreatment is aimed to increase accessibility by improving the physicochemical properties and composition of lignocellulosic biomass. It is the first and the most critical step that needs to be carefully selected and designed to overcome the constraints and improve the overall efficiency of bioethanol production. In recent years, ball milling has been applied as an emerging technique to produce bioethanol from lignocellulosic biomass efficiently and in an environment-friendly manner. Furthermore, ball milling technique coupled with chemical and physicochemical pretreatments has been shown to facilitate lignin removal, reduce cellulose crystallinity, and increase the specific surface area which ultimately improves the digestibility of lignocellulosic biomass. Over the last decade, several reports have been published on the application of ball milling to intensify the pretreatment process. However, a compiled report showing the progress of the technology in bioethanol processing is absent. In this review, a critical analysis and evaluation of published works on ball milling and ball milling-assisted chemical/physicochemical pretreatments are presented. It also addresses the synergistic effects of combining ball milling and chemical/physicochemical treatments to bring desirable characteristics of lignocellulosic biomass that will eventually improve hydrolysis yield and reduce chemical and energy consumption in bioethanol production.
Lignocellulosic biomass as a renewable and valuable resource has been a very active research area during recent years. Ionic liquids (ILs) are an attractive approach for the pretreatment of lignocelluloses. In this work, a series of pyrrolidinium-based ionic liquids were prepared simply and were investigated for the pretreatment of corn stalk at 90 degrees C for 30 min. The characteristics of regenerated lignin and cellulose-rich materials were determined by Fourier transform infrared spectroscopy (FTIR) analysis. Both ILs and ILs/H2O were studied. Notably, 10.17\% lignin based on the original corn stalk was recovered with {[
The objective of the present study was to develop a sono-assisted acid pretreatment strategy for the effective removal of lignin and hemicelluloses and to improve the sugar yield from chili post harvest residue. Operational parameters that affect the pretreatment efficiency were studied and optimized. Inhibitor analysis of the hydrolyzate revealed that major fermentation inhibitors like furfural, hydroxymethyl furfural and organic acids like citric acid, succinic acid and propionic acid were absent. Changes in structural properties of the biomass were studied in relation to the pretreatment process using scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier Transform Infrared (FTIR) analysis, and the changes in chemical composition was also monitored. The biomass pretreated with the optimized novel method yielded 0.465 g/g of reducing sugars on enzymatic hydrolysis. Fermentation of the non-detoxified hydrolysate yielded 2.14\% of bioethanol with a fermentation efficiency of 71.03\%. (C) 2016 Elsevier Ltd. All rights reserved.
The objective of this research was to determine the mechanical properties, including among others compressive strength (fc), tensile strength (fsp), flexural strength (fr), modulus of elasticity (Ec), and Poisson's ratio () of a brick aggregate concrete (BAC) containing rice husk ash (RHA) as a partial replacement of cement. Concrete cylinders with 100-mm diameter and 200-mm height were cast using 0-25\% RHA as a partial replacement of cement with water-to-binder ratios of 0.45, 0.50, and 0.55, with a mix ratio of 1:1.5:3, and cured in water at room temperature. The experimental results indicated that fc and fsp increased gradually with the increasing RHA up to 15\%. However, the maximum values of these were observed with 10\% RHA. By contrast, fr of BAC containing up to 25\% RHA was found lower than that of control concrete. Ec and of BAC with RHA were higher than those of control concrete. It was observed that mechanical properties of BAC were influenced significantly due to the inclusion of 15\% RHA as a partial replacement of cement with a water-to-binder ratio of 0.50.
Production of inulinase by solid state fermentation always involves an extraction step. In this study, the effects of the type of solvent, solid/liquid ratio, stirring rate, temperature, and extraction time on the recovery of inulinase from solid state fermentation of Aspergillus ficuum JNSP5-06 were investigated. After determining the best solvent, the extraction parameters for inulinase recovery were optimized by central composite rotatable design. The results showed that the maximum recovery of inulinase was obtained using 0.1 M sodium acetate of pH 4.5 as extraction solvent, in a solid/liquid ratio of 1:20.5, at 39.6 degrees C and 207 rpm for 40 min. (C) 2011 Elsevier Ltd. All rights reserved.
The development of a feasible biorefinery is in need of alternative technologies to improve lignocellulosic biomass conversion by the suitable use of energy. Microwave heating processing (MHP) is emerging as promising unconventional pretreatment of lignocellulosic materials (LCMs). MHP applied as pretreatment induces LCMs breakdown through the molecular collision caused by the dielectric polarization. Polar particles movement generates a quick heating consequently the temperatures and times of process are lower. In this way, MHP has positioned as green technology in comparison with other types of heating. Microwave technology represents an excellent option to obtain susceptible substrates to enzymatic saccharification and subsequently in the production of bioethanol and high-added compounds. However, it is still necessary to study the dielectric properties of materials, and conduct economic studies to achieve development in pilot and industrial scale. This work aims to provide an overview of recent progress and alternative configurations for combining the application of microwave technology on the pretreatment of LCMs in terms of biorefinery. (C) 2017 Elsevier Ltd. All rights reserved.
In this study, it was the first time to report that the cellulases of Galactomyces sp. CCZU11-1 showed high activity and stability in the culture and reaction media containing IL {[
As a developing country with the largest population, China faces a serious challenge in satisfying its continuously increasing energy demand, especially for liquid fuel. Bioethanol production from lignocellulosic material is a potential and feasible method to solve the many problems in China, and it was supported by the Chinese government. Many research projects in China on lignocellulosics ethanol production have been carried out. After more than 30 years of research, several pilot scale facilities have been constructed. This review focuses on the recent research activities and developments in lignocellulosic ethanol production during the past decade in China. As case study, a corncob biorefinery process is introduced. (C) 2009 Elsevier Ltd. All rights reserved.
This study investigates the technical, economic and environmental performances for producing ethanol and furfural from Pinus patula bark, on a biorefinery concept. This was done through experimental, techno-economic and environmental assessments. The experimental analysis considered the physicochemical characterization of the raw material and three pre-treatment methods: (i) dilute acid, (ii) alkali, and (iii) liquid hot water. The alkali method showed the highest yield (50\%) and the pentose rich hydrolysate was used to produce furfural (yield 91\%). The solid from the pre-treatment stage was enzymatically hydrolyzed (max concentration 63 g/l), and the hexose rich solution was used as substrate for producing ethanol (0.42 g ethanol/g sugars). The obtained experimental yields were used as the basis to build a process model to generate mass and energy balances, from which the techno-economic and environmental assessments are derived. Based on different levels of heat integration, three scenarios were assessed: (Sc.1) non-integrated, (Sc.2) fully energy integrated and (Sc.3) fully integrated plus cogeneration scheme. Results revealed that by increasing the level of energy integration, the biorefinery system can be profitable with a positive net present value (Sc.3: 18454 M.USD/y) and a payout period within the project's life-time (Sc.3: 2.22 y). The annualized production costs can be decreased up to 84\% and 66\% for scenario 3 in comparison with scenarios 1 and 2, respectively. From the environmental point of view, the biorefinery system is positively affected by increasing the level of energy integration. The potential environmental impact can be reduced up to 74\% and 66\% for scenario 3, in comparison with scenarios 1 and 2, respectively. (C) 2015 Elsevier Ltd. All rights reserved.
Corncob agricultural waste was used as a source of arabinoxylan for preparation of films. Three arabinoxylan samples were prepared: crude extract (CCAX), purified by a washing step, and purified by bleaching CCAX. Films prepared with untreated CCAX were water soluble, yellowish in color and had poor mechanical properties. After the purification processes the Young's modulus increased from similar to 293 MPa to similar to 1400-1600 MPa, and strength was improved from similar to 9 MPa to around 53 MPa, while the strain at break was kept at similar to 8\% both in untreated and purified CCAX. The contact angle was increased from similar to 21.3 degrees to 67-74 degrees after washing or bleaching CCAX. Acetylation of bleached CCAX showed the highest thermal resistance (325 degrees C), had low T-g (125 degrees C) and a high contact angle (80 degrees), and its films were stronger (strength similar to 67 MPa; Young's modulus similar to 2241 MPa) and more flexible (similar to 13\%). These characteristics make purified CCAX a suitable material to be used as a matrix for film applications. (C) 2013 Elsevier Ltd. All rights reserved.
Di-O-(6-azidohexanoyl)-xylan-graft-poly(L-lactide)s (XylC6N(3)-g-PLLAs) were prepared by grafting propargyl-terminated poly(L-lactide) onto di-O-(6-azidohexanoyl)-xylan (XylC6N(3)) via click chemistry. Di-O-(6-azidohexanoyl)-xylan (XylC6N3) was prepared via two steps from xylan extracted from eucalyptus kraft pulp with aqueous sodium hydroxide solution. Propargyl-terminated poly(L-lactide)s (PLLA) with three different molecular weights were synthesized via ring-opening polymerization of L-lactide using propargyl alcohol as initiator and tin (II) octanoate (Sn(Oct)(2)) as catalyst. XylC6N(3) and propargyl-terminated PLLAs were treated with N,N,N',N',N `'-pentamethyldiethylenetriamine (PMDETA) and copper(I) bromide, and the graft copolymers XylC6N(3)-g-PLLAs were obtained. DSC measurements revealed that the glass transition temperatures (T-g) of the copolymers decreased compared to that of XylC6N3, suggesting that the grafted PLLA side-chains act as an internal plasticizer for xylan. TGA measurements revealed that XylC6N(3)-g-PLLAs had higher decomposition temperatures than those of XylC6N3 or PLLA, and that the decomposition temperatures of the copolymers increased with decrease in the number of PLLA side-chains grafted to the xylan main-chain. (C) 2011 Elsevier Ltd. All rights reserved.
The present investigation evaluated Cogongrass as a prospective non-edible feedstock for second-generation bioethanol. An innovative recycling-based strategy was employed to minimize chemical consumption and wastewater generation during the mild-alkali pretreatment. The biomass was pretreated with 2\% (W/V) sodium hydroxide (SH) solution at 85 degrees C for 90 min and subsequently subjected to separate saccharification and fermentation. Accordingly, the produced black liquor (BL) and waste wash-water (WWW) were sequentially withdrawn and partially fed back to the next pretreatment and washing processes, respectively. The results indicated that enzymatic hydrolysis of the biomass was substantially improved from 24.8\% up to 90.8\% following the alkali pretreatment; and afterward, it was progressively decreased to a minimum value of 66.4\% upon recycling BL and WWW for ten times. Parallel hydrolysis experiments were conducted in the presence of three non-ionic environmentally-friendly surfactants at different concentrations (0.25-2\% V/V). Notably, supplementation with 0.5\% (V/V) Tween 80 significantly improved hydrolysis yield of recycled BL (RBL) pretreated substrate to a maximum value of similar to 88\%. Fermentation of the RBL-pretreated Cogongrass did not reveal any cell inhibition and resulted in maximum similar to 76\% ethanol production yield, while also saving 59\% of the water consumption and over 45\% of the alkali usage. Detailed analyses of the biomass using semi-quantitative techniques revealed that enhanced cellulose accessibility to the enzyme, decreased crystallinity, and extensive lignin and hemicellulose removal were the key factors contributing to the observed improvements.
Bamboo was submitted to ultrasound-assisted extraction in aqueous ethanol to evaluate the effect of ultrasonic irradiation on the dissolution of lignin. In this case, the dewaxed bamboo culms were subjected to ball milling for 48 h, and then were suspended in 95\% ethanol followed by ultrasonic irradiations for varied times at 20 degrees C to obtain ethanol-soluble fractions. The structural and thermal properties of the ethanol-soluble fractions were comparatively investigated by chemical analysis including alkaline nitrobenzene oxidation, bound carbohydrate determination, FT-IR spectra, HSQC spectra, TG, and DTA. The results showed that the yields of the ethanol-soluble fractions were between 4.29\% and 4.76\% for the fractions prepared with ultrasonic irradiation time ranging from 5 to 55 min, as compared to 4.02\% for the fraction prepared without ultrasonic irradiation. It was found that the lignin content of the fraction increased with the increase of the ultrasonic irradiation time. There was a slight increase of the molecular weight of the lignin with the increase of the ultrasonic irradiation time. Alkaline nitrobenzene oxidation coupled with HSQC analysis indicated that the lignin in the fractions was mainly composed of G S H type units as well as minor amounts of ferulic acids. In addition, the fraction prepared with ultrasonic irradiation exhibited a slightly higher thermal stability as compared to the fraction prepared without ultrasonic irradiation. (C) 2011 Elsevier B.V. All rights reserved.
Lubricant oil is considered a hazardous waste, and its disposal in the environment represents a high risk of damage to ecosystems. The purpose of this work is to study the feasibility of using lubricating oil re-refining ash (LORR) as a pozzolanic material in mortar composites with 0-40\% of cement replaced by LORR, and determining the optimal content. Systematic experiments were performed to investigate the effects of LORR on the cemen-titious material properties, including workability, mechanical and flexural strength and water absorption. Furthermore, the hydration of the cement pastes was analyzed using thermogravimetric analysis (TGA) and X-ray diffraction (XRD). The results showed that LORR has high pozzolanic reactivity, increasing portlandite con-sumption, contributing to the additional formation of calcium silicate hydrate gel. Up to 30\% LORR replacement resulted in similar mechanical properties to the control mortar. The leaching test showed that the raw LORR release 9 hazardous substances, including 6 heavy metals. The mortar proved to be effective for encapsulating all substances studied, in addition to contributing to the reduction of hazardous waste deposition in industrial landfills, and reducing the cost (less than24\%) and embodied energy (less than29\%) of eco-friendly cementitious materials. Therefore, the potential of lubricating oil re-refining ash for application in civil construction was demonstrated.
In this study, response surface methodology was used to study the effects of H2SO4, concentrations, substrate loading and residence time on liberation of reducing sugars (RS), total sugars (TS) and total phenolic compounds from poplar leaves and twigs. Box-Behnken design with three variables and three levels showed maximum release of total phenolic compounds (57.39 mg/ml) corresponding to 0.8\% H2SO4 concentration, 15\% substrate level with residence time of 4 h. Under these conditions, the TS and RS released up to 161.20 and 5.24 mg/ml, respectively. Analysis of the pretreated substrate by Fourier transform infra-red and X-ray diffraction revealed the effectiveness of pretreatment conditions. Second-order polynomial equation using analysis of variance was employed for analyzing the results. The proposed model was found very significant with F-value of 48.39. The R-2 and adjusted R-2 values also revealed the accuracy of predicted response. {[
Brewer's spent grain is the byproduct of brew industry and can be a low cost feedstock for bioethanol production. It can be converted into ethanol by the process of fermentation. In the present study, Fusarium oxysporum and Saccahromyces cerevisiae were used as source of enzymes for simultaneous saccharification and fermentation of spent grain into ethanol. Experiments were performed to identify the optimized conditions, temperature, ratio of both species in culture media, pH, Stimulating sugar concentration for both single and mixed culture. The enhancement in bioethanol was observed using mixed culture. Ethanol yield of 57\% was obtained in bioreactor with mixed culture, which is higher than the amount obtained using single culture of Fusarium (26\%) and Saccharomyces (33\%) at the same optimum conditions of temperature (30 degrees C), pH (6), and stimulating sugars concentration (0.3\% w/v). Efficient bioethanol production was achieved using the ligno-cellulolytic degrading enzyme machinery of F. oxysporum. (C) 2013 AIP Publishing LLC.
Rice husk is an abundant agricultural by-product with the annual output of 120 and 40 million tons in the world and China, respectively. The common disposal method of rice husk in China has caused the pollution. This manuscript deals with a new method of comprehensively utilizing rice husk, by which hazardous materials are avoided to release. 100.3, 219.4, 50.1 and 170.5 g of D-xylose, organosolv lignin, ethanol and superfine silica are consecutively prepared from 1000g of rice husk. This new method is helpful to resolving the problem of pollution and waste aroused by rice husk. (C) 2015 Elsevier B.V. All rights reserved.
Bricks are extensively used building material all over the world owing to their low price, frequent availability, and ease of handling. However, as a matter of fact, they also consume a huge quantity of good quality clay. In this research, Brick Kiln Dust (BKD) was used as partial replacement of fresh clay in bricks. The replacement percentages were kept as 0\%, 5\%, 10\%, 15\%, 20\% and 25\% by mass of fresh clay. In total 300 brick samples were prepared. The bricks prepared by incorporating the waste materials were analyzed for their physical, chemical and mechanical properties and the results were compared with those obtained from the control samples. The brick specimen were evaluated for their unit weight, water absorption, apparent porosity, efflorescence, pore size distribution, micro structure, crystalline phases, chemical composition, compressive and flexural strength, and sulfate attack resistance. The results indicate that the inclusion of BKD marginally reduces the mechanical strength, increases water absorption capacity, results in lower unit weight and higher resistance to efflorescence and are useful for insulation owing to high porosity. The research concludes that the BKD may be incorporated in the production of clayey bricks, saving as much as 25\% of fertile clay, which is environmentally very beneficial.
Oil palm empty fruit bunches (OPEFBs) can be transformed into composite boards with higher selling value when their cellulose is used as a fiber. Manufacturing composites with hybridization techniques can improve their properties. This study combined OPEFBs and ramie fibers in an epoxy-carbon nanotube (CNT) matrix. The proportion of OPEFBs and ramie fibers was varied (3:7, 5:5, and 7:3), with a total fiber content of 10\% by volume and a matrix of 90\% by volume. Alkali treatment using NaOH solution was applied to the fiber to remove impurities from the surface. CNTs were functionalized using nitric acid followed by hydrogen peroxide to improve compatibility. Surface treatment was conducted on fibers and CNTs to increase the bonds between these components in the composite material. The hybridization of OPEFBs/ramie fibers improved the tensile strength in the 3:7TR, 5:5TR, and 7:3TR composites by 127, 37, and 12\%, respectively, compared to the 10T composite. The flexural strength of the 5:5TR hybrid composite increased by 120\%, and that of the 3:7TR and 7:3TR composites increased by 83\% against the 10R composite. The 3:7TR hybrid composite showed the best mechanical properties.
The increasing demand for petroleum-based polyethylene terephthalate (PET) grows population impacts daily. A greener and more sustainable raw material, lignocellulose, is a promising replacement of petroleum-based raw materials to convert into bio-PET. This paper reviews the recent development of lignocellulose conversion into bio-PET through bioethanol reaction pathways. This review addresses lignocellulose properties, bioethanol production processes, separation processes of bioethanol, and the production of bio-terephthalic acid and bio-polyethylene terephthalate. The article also discusses the current industries that manufacture alcohol-based raw materials for bio-PET or bio-PET products. In the future, the production of bio-PET from biomass will increase due to the scarcity of petroleum-based raw materials.
Four ammonium-based ionic liquids were synthesized for the selective extraction and degradation of lignin from coffee husk. The extracted lignin samples were characterized by Fourier transform infrared, gel permeation chromatography, gas chromatography-mass spectrometry, UV-vis, H-1 and C-13 NMR, heteronuclear single-quantum coherence-NMR, thermogravimetric analysis, X-ray diffraction, and field emission scanning electron microscopy analyses. The analyzed results confirmed that these ionic liquids are able to effectively extract and decompose the lignin to smaller molecules from the biomass. Experimental results show that a significantly high yield, 71.2\% of the original lignin, has been achieved. This processing method is an efficient, economical, and environmentally friendly green route for producing high-added-value lignin from wasted coffee husk.
The enzymatic digestibility of softwood is hindered for its highly recalcitrant nature to enzymatic attack. In this study, the effects of dilute sulfuric acid pretreatment (DSAP), acidic sodium chlorite pretreatment (SCP), and their combined pretreatments (DSA-SCP and SC-DSAP) on Chinese fir sawdust were investigated, respectively. Results demonstrated that lignin was the most important obstacle, and digestibility increased linearly with lignin removal yield. Furthermore, the results revealed that the order of sequential pretreatment significantly affected the delignification, and hemicellulose should be removed first. Compared to SC-DSAP, DSA-SCP involving the hemicellulose-removal-first strategy exhibited higher delignification efficiency. DSA-SCP caused lignin removal of 92.3\% and the enzymatic hydrolysis was high of 97.9\%. Finally, a regression model with high reliability was established to quickly evaluate pretreatment process. In summary, this study highlighted the importance of delignification for saccharification of softwood and unveiled the effect of hemicellulose on delignification.
Lignocellulose-based processes for production of value-added products still face bottlenecks to attain feasibility. The key might lie on the biorefining of all lignocellulose main polymers, that is, cellulose, hemicellulose and lignin. Lignin, considered an impediment in the access of cellulose and normally considered for energy recovery purposes, can give a higher contribution towards profitability of lignocellulosic biorefineries. Organosolv pretreatment allows selective fractionation of lignocellulose into separate cellulose-, hemicellulose- and lignin-rich streams. Ethanol organosolv and wood substrates dominated the research studies, while a wide range of substrates need definition on the most suitable organosolv pretreatment systems. Techno-economic and environmental analyses of organosolv-based processes as well as proper valorization strategies of the hemicellulose-rich fraction are still scarce. In view of dominance of ethanol organosolv with high delignification yields and high-purity of the recovered cellulose-rich fractions, close R \& D collaboration with 1st generation ethanol plants might boost commercialization.
Pretreatment process plays a key role in biofuel production from lignocellulosic feedstocks. A study on dilute NaOH pretreatment supplemented with H2O2 under mild condition was conducted to overcome the recalcitrance of grass waste (GW). The optimized process could selectively increase lignin removal (73.2\%), resulting in high overall recovery of holocellulose (73.8\%) as well as high enzymolysis efficiency (83.5\%) compared to H2O2 or NaOH pretreatment. The analyses by Scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) revealed that supplementary H2O2 disrupted the structure of GW to facilitate the removal of lignin by NaOH, and exhibited synergistic effect on lignin removal and enzymolysis with dilute NaOH. Moreover, high titer of ethanol (100.7 g/L) was achieved by SSCF on 30\% (w/v) pretreated GW loading. The present study suggests that the established synergistic pretreatment is a simple, efficient, and promising process for GW biorefinery.
The chemical modification of birch wood xylan was undertaken in the ionic liquid 1-n-butyl-3-methylimidazolium chloride (C(4)mimCl) using three different long-chain succinic anhydrides: n-octenyl succinic anhydride (n-OSA), n-dodecenyl succinic anhydride (n-DDSA) and n-octadecenyl succinic anhydride (n-ODSA). Reactions were performed at temperatures of 80-100 degrees C and reaction times of 0.5-22 hours resulting in a degree of substitution (DS) of 0.08-0.27. The formation of the desired products was confirmed through the use of H-1 NMR and FT-IR, while DS was determined by titration. Thermogravimetric analysis of the modified and native xylans showed a slight lowering of thermal stability with functionalization. Contact angle measurements on spin-coated surfaces of modified xylan films showed a significant increase in hydrophobicity with the introduction of the alkenyl-functionalized succinic anhydride moieties.
Environmental problems due to utilization of fossil-derived materials for energy and chemical generation has prompted the use of renewable alternative sources, such as lignocellulose biomass (LB). Indeed, the production of biomolecules and biofuels from LB is among the most important current research topics aiming to development a sustainable bioeconomy. Yet, the industrial use of LB is limited by the recalcitrance of biomass, which impairs the hydrolysis of the carbohydrate fractions. Hydrodynamic cavitation (HC) and Advanced Oxidative Processes (AOPs) has been proposed as innovative pretreatment strategies aiming to reduce process time and chemical inputs. Therefore, the underlying mechanisms, procedural strategies, influence on biomass structure, and research gaps were critically discussed in this review. The performed discussion can contribute to future developments, giving a wide overview of the main involved aspects.
In this study, the effects of several factors on NaoH pretreatment of Achnatherum splendens were investigated It was found that NaOH I loading liquid-to-solid ratio and reaction temperature all had significant effects on delignification. These factors also had Significant effects on the contents of lignin, hemicellulose and cellulose in the solids after NaOH pretreatment. The optimal pretreatment conditions were found to 15\% of NaOH loading; 10:1 of liquid-to-solid ratio, 90 degrees C and 90 min of reaction time Under the optimal conditions, approximate 39\% of lignin was solubilized and the cellulose content was increased to 68.39\% while the lignin and hemicellulose contents were decreased to 9.28\%, 19.86\% respectively. The lignin was effectively removed by NaOH pretreatment under mild conditions. The results could be considered as a step towards the optimization of NaOH pretreatment of Achnatherum splendens.
The production of renewable and sustainable biofuels using inevitable wastes is a promising alternative to the alarming depletion of fossil fuels. Significantly, the sustainable biorefinery of lignocellulosic waste, as an alternative fuel source, is a prognosticating approach to tackle many agricultural/forestry residues and offers a circular economy as well as environmental benefits. But, the heterogeneity of lignocellulosic biomass is one of the major bottlenecks in lignocellulosic biorefinery. Thus the characterization of lignocellulosic biomass is essential to understanding the feedstock's nature, composition and suitability for biofuel production. The present study taps evergreen spiny non-edible pods of Prosopis juliflora (Pj) as an energy feedstock. Proximate, ultimate and biochemical characterization of Pj pods were conducted, and thermal behaviour and calorific values were determined. Cellulose and hemicellulose were isolated and characterized by reliable methods. The overall characterization has revealed the Pj pods as a potential feedstock for bioenergy. The collected Pj pods contain (\% w/w) moisture 7.89 +/- 0.002, volatile matter 87.67 +/- 0.002, ash 0.21 +/- 0.002, fixed carbon 4.23 +/- 0.002 with a calorific value of 17.62 kg/MJ. The CHNS content was (w/w \%) carbon 41.77, nitrogen 3.58, sulfur 26.3 and hydrogen 6.55. The biochemical composition analysis yields (\% w/w) on a dry basis; cellulose 26.6 +/- 0.18, hemicellulose 30.86 +/- 0.27, lignin 4.71 +/- 0.12, protein 11.63 +/- 0.12 and starch 1.1 +/- 0.06 and extractives 30.56 +/- 0.008. The isolated cellulose and hemicellulose were analyzed and confirmed by CP/MAS \&H-1 NMR, FTIR, TG-DSC, SEM, XRD, and TGA. The present results revealed that the tested biomass, Prosopis juliflora, could be used as a feedstock in biorefinery for bioenergy.
Investigation of an alternative source of the nonrenewable energy is attracting the world attention nowadays. The fruits and leaves biomass of Calotropis procera were exposed to sequential pretreatment processes. First, a successive pretreatment with an organic solvent (hexane/methanol) yielded biocrude and plant spent residues fractions. The plant spent residues fractions were exposed to successive acid/alkali (1\% H2SO4/2\% NaOH) pretreatment to yield spent residues of fruits (SRF) and leaves (SRL). The amount of cellulose content of the sequential pretreated SRF and SRL were 87.3 and 83.4\%, respectively. The hydrolysis process of 10 g of the sequential pretreated SRF and SRL by Sternzym cellulase produced 80.2 and 50.4 g/L of total reduced sugars, respectively. The reduced sugars were then fermented by Saccharomyces cerevisiae (MN901244) for bioethanol production. The HPLC analysis showed 38.9 and 23.8 g/L of bioethanol yields from sequential pretreated SRF and SRL, respectively. The GC/MS analysis of methanol and hexane biocrude fractions revealed the presence of 20 and 12\% of fatty acids, respectively, which would be promising amounts for biodiesel production after esterification. So, the present study suggested a low-cost nonedible plant biomass (Calotropis procera) as a biorefinery for production of renewable bioethanol.
Rice husk (RH) is the major agricultural waste obtained during rice hulling process, which can be a sustainable source of xylooligosaccharide (XOS). The current study deals with the production of XOS from Thai rice husk using alkaline pretreatment and enzyme hydrolysis method. The response surface methodology consisted of central composite design and Box-Behnken design was employed to achieve the maximum response in alkaline pretreatment and XOS production, respectively. The optimum conditions for alkaline pretreatment to recover maximum xylan yield were 12-18\% of alkaline concentration, the temperature at 110-120 degrees C, and steaming time for 37.5-40 min. The FTIR results suggested that the extracted sample was the xylan fraction. The maximum XOS production of 17.35 +/- 0.31 mg XOS per mL xylan was observed in the run conditions of 6.25 mg enzyme per g xylan, 9 h of incubation time, and 5\% of xylan. The results revealed that the xylan extracted from RH by using an effective base couple with the steam application and the enzymatic hydrolysis help to maximize the yield of XOS, which can be further used in functional foods and dietary supplements.
Effective utilization of winter bamboo shoot shell (BSS) is of great interest, since BSS provides a renewable and inexpensive bioresource for the production of biofuels. In this study, an effective combination pretreatment by the sequential aqueous ammonia (25 wt\%) extraction at 50 degrees C for 24 h and LiCl/N,N-dimethyl formamide (LiCl/DMF) (6 wt\% of LiCl) pretreatment at 50 degrees C for 8 h was used for pretreating BSS. SEM, FTIR, and XRD results indicated that combination pretreatment could effectively remove lignin and change the crystal structure of cellulose for promoting enzymatic saccharification. Additionally, significant linear correlations were found about solid recovery-delignification (R-2 = 0.9235), delignification-reducing sugars (R-2 = 0.9552), and delignification-hemicellulose removal (R-2 = 0.9779) during the combination pretreatment. The reducing sugars and glucose from the hydrolysis of 100 g/L pretreated BSS could be obtained at 72.3 and 40.5 g/L, respectively. Using the recovered BSS-hydrolysates containing 20-50 g/L glucose as carbon source, the ethanol yields at 48 h could be obtained at 84.5-86.1\% of the theoretical yield. In conclusion, the sequential ammonia extraction and LiCl/DMF pretreatment has high potential application in future.
Rice husk is a readily available residue which can be used for producing bioproducts in a biorefinery context. In this study, the hemicellulose fraction was hydrolyzed in a hydrothermal process to produce xylooligosaccharides (XOS), whereas the cellulosic hydrolysate was used for red pigment production by Monascus ruber Tieghem IOC 2225. The highest XOS (X2-X4) production (24 g per 1 kg of rice husk) was achieved at 180 degrees C for 68 min in a non-stirred Parr reactor (50 mL). Subsequently, using a stirred parr reactor (1 L) at 180 degrees C for 60 min, 40 g of XOS (42\% of xylobiose, 35\% of xylobiose, 13\% of xylotriose, 7\% of xylotetraose, and 3\% of xylopentaose) per 1 kg of rice husk were obtained. The XOS was then purified by using ultrafiltration (UF) with two diafiltration membranes at 6.5 pH, recovering approximately 92\% of total XOS. Further purification was conducted with nanofiltration (NF) at 3.8 pH, recovering approximately 86.4\% of XOS in the retentate. This process yielded XOS with a purity of 77\%. Additionally, the enzymatic process yielded 132 g/kg of sugar, and the hydrolysate was used to produce 2.1 UA490nm of red pigment by fungi after 7 days.
The flue gas emissions from co-combustion of anthracite powder and water hyacinth were characterized. The effects of combustion temperature, mixing ratio, and oxygen concentration on SO2 and NOx emissions were studied. On this basis, the response surface test was designed. When the ratio of water hyacinth in the mixed fuels was higher, the SO2 and NOx emissions were minimized at the mixing ratios of 5/5 and 8/2 respectively. Among all tested combustion temperatures, the total emission of SO2 and NOx were maximized at 900 degrees C. Among all tested oxygen concentrations, the total emission of SO2 and NOx maximized at the oxygen concentration of 50\%. The influence factors on SO2 and NOx emissions rank as oxygen concentration > mixing ratio > temperature.
Acid/base conjugate of acetic acid/sodium acetate solution (AC/SA) can efficiently produce xylooligosaccharides (XOS) with relatively high purity from poplar. The lignin in poplar is an important factor limiting the hydrolysis of xylan using enzymes and dilute acids. Until now, the effect of lignin content of poplar on XOS production by AC/SA hydrolysis is not clear. This work examined the relationship between lignin removal and XOS production from poplar by AC/SA hydrolysis. It was revealed that lignin removal of poplar enhanced XOS yield almost linearly (R2 = 0.95) in AC/SA hydrolysis. Under the optimal conditions (0.15 M AC/SA at a molar ratio of 3.0, 170 degrees C, 60 min), the highest XOS yield of 55.7\% with a low xylose yield of 4.1\% was obtained from poplar at a preferential lignin removal of 84.0\%. Compared to the optimal XOS production from raw poplar, the XOS yield was increased by 32.3\% and xylose production was decreased by 41.4\%. Cellulase hydrolysis of the poplar residue produced a satisfying glucose yield of 92.8\% and a xylose yield of 88.4\%. This work proved that pref-erential delignification of poplar was vital in XOS and monosaccharides production by AC/SA hydrolysis com-bined with enzymatic hydrolysis.
In this study, six different herbal-extraction residues were evaluated for succinic acid production in terms of chemical composition before and after dilute acid pretreatment (DAP) and sugar release performance. Chemical composition showed that pretreated residues of Glycyrrhiza uralensis Fisch (GUR) and Morus alba L. (MAR) had the highest cellulose content, 50\% and 52\%, respectively. Higher concentrations of free sugars (71.6 g/L total sugar) and higher hydrolysis yield (92\%) were both obtained under 40 FPU/g DM at 10\% solid loading for GUR. Using scanning electron microscopy (SEM), GUR was found to show a less compact structure due to process of extraction. Specifically, the fibers in pretreated GUR were coarse and disordered compared with that of GUR indicated by SEM. Finally, 65 g/L succinic acid was produced with a higher yield of 0.89 g/g total sugar or 0.49 g/g GUR. Our results illustrate the potential of GUR for succinic acid production.
Sugar generated from aquatic plant biomass with high cellulose and hemicellulose content is considered as a dynamic progression towards the advancement in bio products. Hence, this study investigated the possibility of enhancing the saccharification rate of sugar from water hyacinth (Eichhornia crassipes) by microwave heating system. The method of full factorial experimental design was adopted to explore different parameters that influence the conversion rates of fibers into fermentable sugar. The structural changes of the fibers after microwave treatment with dilute sulfuric acid was observed on the residue by using X-ray Diffractometer (XRD), Fourier Transform Infrared Spectrometry (FTIR) and Environmental Scanning Electron Micrograph (ESEM) analysis. The results obtained illustrates that hydrolysis time reduces to approximately 40\% and effectively improve the rate of saccharification to 13.94\% with optimal sugar concentration of 4650 mg/L. (C) 2018 Elsevier Ltd. All rights reserved.
Lignocellulosic biomass (LCB) such as crop residues and agro-industrial wastes are renewable resources and available abundantly. It could play central role in sustainable feeding system of ruminant production. These materials are potential source of fiber to support optimum rumen function and energy supply. However, the LCB has important nutritional constraints that limit its utilization as feed for ruminants. This review is intended to discuss nutritional constraints of LCB as ruminant feed and the potentials and challenges of processes in upgrading the nutritional quality of LCB. The main polymer compounds in LCB are cellulose (30 to 60\% ), hemicellulose (20 to 40 \%) and lignin (15-25\%) and its inter linkages make the energy contained in the LCB is less extractable by the ruminant digestive system. Physical, chemical and biological processing technologies have been well known as alternative means to upgrade the nutritive values of LCB. Recently, novel processing technologies of LCB such as ionic liquid, organosolv, sonication, and new screened rot white fungi (Ceriporiopsis subvermispora) and some older technologies using alkaline and acids have been studied and developed particularly for the purpose of biofuel production in the bio refinery industry. Processing technologies have different properties in degrading the lignin, degrading and solubilizing the cellulose and hemicellulose that all relate to the nutritive quality of LCB. Advantages of processed LCB in ruminant animals were indicated by increase in diet digestibility, intake, rumen fermentation and gain. It is concluded that numerous processing technologies are available to upgrade the nutritional quality of LCB, but there are obstacles to use some of these techniques for wide application in ruminant production system.
Novel laccases have promising and valuable applications in biorefineries. This investigation documents, for the first time, the potential of depolymerising and repolymerising lignin by the secretome, rich in laccases, from a newly isolated white-rot basidiomycete Marasmiellus palmivorus VE111, for further saccharification and ethanolic fermentation steps. Proteomic analyses of the secretome of M. palmivorus show that laccases are the most predominant enzyme released by this fungus. The whole crude enzymatic broth is used for the delignification of lignin in Eucalyptus globulus wood, with the aim of enhancing the saccharification by cellulolytic and xylanolytic enzymes from Penicillium echinulatum S1M29. In addition, two different strategies, namely, laccase treatment before and after enzymatic hydrolysis, are employed to detoxify steam-exploded E. globulus wood. The objective is to increase the fermentative performance by removing substances formed during the feedstock pretreatment that can inhibit microbial fermentation. The E. globulus wood delignification results in a 31\% decrease in the lignin content and a 10\% increase in the glucose yield after hydrolysis. An important finding of the present work is the successful wood delignification in the absence of laccase mediators. This laccase-rich preparation also demonstrates its potential in removing the phenolic inhibitors present in steam-exploded E. globulus wood, increasing the ethanol yield by an additional 10\%. Furthermore, it is important to highlight that these findings are achieved in the absence of commercial enzymes, making M. palmivorus laccases a potential candidate not only for the production of biofuels but also for the generation of lignin-derived aromatic compounds for different applications in the biotechnology industry.
The reliability of the electrical resistivity technique in concrete was assessed. A 0.5 w/c concrete mixture was prepared and three small-scale rectangular prisms were cast. The prisms were submerged in a chloride solution for eight years, and ER measurements were taken weekly during the last five years. The results showed that the seasonal fluctuations of temperature over time and chloride ingress notably influence the ER readings. For exhaustive analysis of the ER, time-series analysis and rate-of-change approaches were used to diminish the effects of temperature and chloride penetration on the ER measurements. Significant differences, which ranged between 10\% and 60\%, were found between the ER values taken on the bottom and top faces of the small-scale ordinary concrete prisms. The reliability of the ER technique and time-series analysis of the data can be implemented easily for engineering works to identify heterogeneities on concrete exposed at environment changes over time.
Formic acid/acetic acid/water mixture used as solvent for acid hydrolysis or pre-hydrolysis of poplar woodchips yields the highest yield of xylose (69.89\%) at 105 degrees C, with a liquor-to-solid ratio of 12:1 (mL/g) for 90 min. The hydrolysate was obtained after recovering formic and acetic acids. Concentrated and neutralized hydrolysate was fermented with Candida tropicalis to produce xylitol. Immobilization of Candida tropicalis was found to enhance the fermentation efficiency. Optimized conditions for preparation and fermentation with Ca-alginate-chitosan beads immobilized Candida tropicalis were determined. The highest yield of xylitol was 40.2\%, obtained under the following fermentation conditions: a rotation speed of 120 rpm, 6 ml of nitrogen source, an initial pH of 6.0, and a volume ratio of 1:4. Hydrolytic residual woodchips were used to produce kraft pulp. Although lower lignin content was found in the residual woodchips, higher chemical charges were needed compared to the untreated woodchips. Lower pulp yield was obtained and the quality of pulps generated at similar pulping conditions was found to be significantly different from the pulps produced from untreated woodchips. The organic solvent treated poplar woodchips could be pulped, however; optimizing the Kraft pulping process is expected. Alternative use of the fibers is to be expected.
Biorefineries have a pivotal role in the bioeconomy scenario for the transition from fossil-based processes towards more sustainable ones relying on renewable resources. Lignocellulose is a prominent feedstock since its abundance and relatively low cost. Microorganisms are often protagonists of biorefineries, as they contribute both to the enzymatic degradation of lignocellulose complex polymers and to the fermentative conversion of the hydrolyzed biomasses into fine and bulk chemicals. Enzymes have therefore become crucial for the development of sustainable biorefineries, being able to provide nutrients to cells from lignocellulose. Enzymatic hydrolysis can be performed by a portfolio of natural enzymes that degrade lignocellulose, often combined into cocktails. As enzymes can be deployed in different operative settings, such as separate hydrolysis and fermentation (SHF) or simultaneous saccharification and fermentation (SSF), their characteristics need to be combined with microbial ones to maximize the process. We therefore reviewed how the optimization of lignocellulose enzymatic hydrolysis can ameliorate bioethanol production when Saccharomyces cerevisiae is used as cell factory. Expanding beyond biofuels, enzymatic cocktail optimization can also be pivotal to unlock the potential of non-Saccharomyces yeasts, which, thanks to broader substrate utilization, inhibitor resistance and peculiar metabolism, can widen the array of feedstocks and products of biorefineries.
Fungal xylanase was produced from lignocellulosic palm wastes through combined solid-state fermentation (SSF) and submerged fermentation (SmF) by Aspergillus tubingensis TSIP9 in a helical-impeller equipped bioreactor. The combined SSF-SmF promoted the xylanase production by 15 and 70\% higher than SSF and SmF, respectively. Sequential purification yielded 7.4-fold purified xylanase with 9.07\% recovery. The maximum activities of crude and purified xylanase were observed at the same pH of 5.0 and the same temperature of 50 degrees C while purified xylanase is more active and highly stable at a wider pH range of 3-8 and temperature of 30-60 degrees C. The half-life of purified xylanase at various temperatures was also much improved by 2-8 folds compared to crude xylanase. Michaelis-Menten constants, V-max and K-m, for purified xylanase are 2,602.8 U/mg and 32.4 mg/mL, respectively. Purified xylanase activity was most enhanced with Ca2+ followed by Zn2+ and Fe2+ at 10 mM while significantly inhibited by Co2+, Cu2+, Pb2+, and Ag+. This study has shown the effectiveness of combined SSF-SmF for xylanase production and superior properties of purified xylanase for industrial processes.
Xylo-oligosaccharides have great value in food, feed fields. Previous studies have shown that organic acids catalyze the hydrolysis of xylan-rich sources for the production of xylo-oligosaccharides. In this study, gluconic acid of aldonic acid generated xylo-oligosaccharides via hydrolysis of xylan from corncob. In order to maximize efficiency of xylo-oligosaccharides production, the optimum conditions was ascertained by Box-Behnken design-based response surface methodology. The developed process resulted in a maximum xylo-oligosaccharides yield of 57.73\% using 4.6\% gluconic acid at 167 degrees C for 28 min, which was similar to the predicted value and fitted models of xylo-oligosaccharides production. The results showed that the reaction temperature was crucial to xylo-oligosaccharides production, and by-product yields (xylose and furfural) could be effectively controlled by both reaction temperature and time. In addition, 44.87 g/L XOS was achieved by decreasing the solid-liquid ratio. Overall, the described process may be a preferred option for future high concentration xylo-oligosaccharides production.
The fermentation products of edible fungi are rich in anthraquinones and have a variety of activities, including the antioxidant activity. Because of the large number of combinations, it is very difficult to obtain the optimal multi-strains co-fermentation to improve the yield of anthraquinone. In the present study, an intelligent model based on artificial neural networks (ANNs) using backpropagation (BP) and radial basis function (RBF) algorithms was developed and validated to predict the anthraquinone contents in 136 two fungi and 680 three fungi co-fermented products. After experimental validation of the anthraquinone contents, the mean absolute error and the mean bias error of the results from RBF ANN were lower than those from BP ANN. The results indicated that the anthraquinone contents in A. bisporus, C. comatus and H. erinaceus co-fermentation product was the highest (2.11\%). Furthermore, this co-fermentation product showed strong antioxidant activity.
Brazil is the largest world producer and consumer of coconut water with approximately two billion fruits, where 70\% is for water production. Therefore, a large amount of waste is generated: the coir husk, which represents approximately 1.75 kg per fruit unit. This biomass presents 35\% cellulose in its composition, which makes the coir husk a good option for the raw material for second-generation (2 G) ethanol production. In this study, the coir husk was chemically pretreated using four different treatments. The 2 G ethanol production was studied considering two different processes, using separated hydrolysis and fermentation (SHF) or simultaneous saccharification and fermentation (SSF). The pretreatment used a solution containing sodium chlorite at 10\% of the acetic acid and the SSF process was the better method for 2 G ethanol production from coir husk, yielding 52.7 L ethanol/ton of biomass. Thus, the coir husk can be considered an alternative for the production of 2 G ethanol, with all the environmental and social advantages of such an approach, such as occupying precious space in the landfills and taking 12 years to decompose.
Hybrid power generation systems that combine more than one renewable resource type are a potential option to improve the capability of renewable power generation systems to meet network demands reliably. This increases the system complexity and cost, so this must be compensated by achieving correspondingly higher capacity factors to achieve similar financial performance to simpler systems. In the analysis undertaken, the hybrid systems developed were limited to combinations of biomass combustion and concentrated solar thermal technology for production of steam to feed a Rankine cycle turbine system. To ensure that resource availability was realistic in the study, biomass availability was based on 5 years of historical data for an existing biomass power generation site in Australia that currently has limited seasonal operations and matching solar data for the same location. A technoeconomic assessment was undertaken in parallel with optimization of plant configurations by inclusion of additional plant components and varying sizing. This included plant designs with different storage capacities, both thermal storage for solar energy and torrefaction char from short-term surpluses of biomass. Several system options were identified where financial performance matched the simple biomass combustion system, but with significant increases in capacity factor through hybridization. (C) 2021 Author(s).
The bio-composite hydrogels consisting of cellulose and vulcanized natural rubber (VNR) were successfully prepared by phase inversion. The hydrogel preparation of cellulose and VNR was performed by mixing a cellulose solution in 6 wt\% lithium chloride in N,N-dimethylacetamide with VNR in toluene at a 10, 15 and 20wt\% VNR loading level. The solution was then exposed to ethanol vapor for 1 day. The cellulose-VNR composites at 10-20 wt\% VNR showed an excellent reinforcement, in terms of higher elastic and mechanical properties, even though the composite hydrogels retained a high amount of water (about 870-2400\%). The nanosize morphology of the composite hydrogels indicated that the roughly aggregated VNR found in the cellulose medium formed with an interconnection layer between both the cellulose and VNR components, where the VNR was surrounded with fibrous cellulose medium. The resulting interconnection between the hydrophobic VNR and hydrophilic cellulose domains at higher VNR-loading levels enhanced the mechanical and elasticity properties of the bio-composite hydrogels.
Green building materials have attracted attention recently due to sustainability issues. Agricultural waste used as alternative raw materials in the manufacturing of building products, fired clay bricks in particular, is an innovative way of waste utilisation. Large quantities of waste are produced in grain processing. New ways of utilising this waste are required for solving this problem. The main objective of this study is to investigate the effects of agricultural solid waste (oat husk and barley husk and middlings) on the physical and mechanical properties and porosity of fired clay bricks. Brick moulding compounds were prepared by adding 5\%, 10\% and 20\% of oat husk or barley husk and middlings and fired at 900 degrees C and 1000 degrees C temperature, keeping them at the highest temperature for 1 h. Oat husk, barley husk and middlings incinerate at 500 degrees C temperature, thus forming a porous structure in the clay body. The addition of 5-10\% of oat husk or barley husk and middlings into brick moulding compound produces eco-friendly fired clay brick having the density of 1300-1800 kg/m(3), compressive strength of 3.3-9.5 MPa, total open porosity of 34-49\%, water absorption 14-28\%. Oat husk or barley husk and middlings reduce the compressive strength of eco-friendly fired clay brick. (C) 2018 Politechnika Wroclawska. Published by Elsevier B.V. All rights reserved.
Chronic venous ulcers (CVU) of the lower limbs (LL) are common and cause psychological changes and significant social impact, as they make the patient susceptible to pain, absence from work and social bonds. Some materials are suggested as dressings for the treatment of CVU, but they are expensive and are generally not available for use in public health services. To evaluate the efficacy of the treatment for lower limbs (LL) chronic venous ulcer (CVU) using bacterial cellulose (BC), gel and multi-perforated film associated. A randomized controlled clinical-intervention study was performed among participants with LL CVU, divided into two groups: experimental (EG), treated with BC wound dressing and control (CG), treated with a cellulose acetate mesh impregnated with essential fatty acids (Rayon (R)). The participants were followed for 180 days, evaluated according to the MEASURE methodology. Thirty-nine patients were treated, 20 from the EG and 19 from the CG. In both groups, the wound area decreased significantly (p < 0.001), the healing rate was similar to the CG. The mean number of dressing changes in the SG was 18.33 +/- 11.78, while in the CG it was 55.24 +/- 25.81, p < 0.001. The healing dressing of bacterial cellulose, gel and associated film, when stimulating the epithelization of the lesions, showed a significant reduction in the initial area, with a percentage of cure similar to the Rayon (R) coverage. In addition to requiring less direct manipulation of ulcers.
A novel magnetic, structured (with ordered pores) and hybrid imprinted polymer (HMMIP) was synthesized to selectively adsorb volatile fatty acids (VFAs) from aqueous matrices. Usual characterization techniques showed that a mesoporous adsorbent was obtained with relatively low specific areas but that could selectively (imprinting factor of 1.64) remove isovaleric acid (used as template) from aqueous solutions and effluents containing VFAs with a good capacity (Q(e) 50 mg g(-1)). From kinetic studies a pseudo-nth-order model showed the best fit to the experimental data and resulted in k (n = 3) equal to 8 x 10(-4) g mg(-1) min(-1) whereas thermodynamic studies indicated that the adsorption of isovaleric acid onto HMMIP was endothermic and entropically driven. Reuse studies indicated that HMMIP loaded with VFA could be efficiently regenerated with acetone-water solution which led to an adsorption loss of ca 10\% after three regeneration/reuse cycles and that the magnetic and specific adsorbent could be removed from complex matrices with an efficiency of ca 77\%. Biochemical methane production assays showed that the addition of HMMIP to anaerobic batch reactors increased by four times the methane production due to the selective adsorption of VFAs. (c) 2020 Society of Chemical Industry
Developing a promising fermentation strategy with high cellulase yield and stable fermenting performance is an imperative way to overcome the cellulase costs limitation. In this study, a novel solid-state fermentation (SSF) strategy using polyurethane carbon foams (PAF) as inert carriers was developed to improve cellulase production by Trichoderma reesei (T. reesei). The effects of significant process parameters such as pore size and thickness of carrier on cellulase production were evaluated. Repeated cycle fermentation using inert carrier for cellulase production was assessed by measuring cellulase activity. Results indicated that inert carrier was conducive to cellulase production and the higher cellulase activity of 0.368 FPU/mL was achieved in SSF with PAF rather than PPF or PUF. More cellulase components could be obtained from SSF with inert carrier compared with submerged fermentation. In addition, higher cellulase activity (0.393 FPU/mL) could be achieved at 0.6 mm pore and 15 mm thickness of PAF. The repeated cycle fermentation experiments showed that maximum cellulase activity of 0.514 FPU/mL was obtained over 6 cycles and the fermentation performance was still stable in SSF with PAF. Therefore, SSF using inert carrier is simple, low cost, and environmentally benign, making it an attractive method for cellulase production.
Biomass pretreatment with protic ionic liquids (PILs) is a promising source of renewable energy and bioproducts, in which different cation/anion combinations may present different behavior towards biomass modification such as selective lignin and/or carbohydrate solubilization. The potential of 20 PILs as pretreatment agents was investigated, whose cations presented two different functional groups and different carbon chain lengths. The best solvent in terms of lignin solubilization during pretreatment was obtained by cations with a functional group (-OH and -NH2). High cellulose conversion was obtained with ethanolamine and ethylenediamine monoacetate ({[
Genetic and enzymatic potential of Neobacillus sedimentimangrovi has not been assembled to date. Here, we report a high-quality genome assembly of thermophilic bacterium Neobacillus sedimentimangrovi UE25 using Illumina Hi-seq 2500. The strain was isolated from a crocodile pond Manghopir, Karachi, Pakistan. QUAST quality parameters showed 37.75\% GC content and exhibited the genome into 110 contigs, with a total size of 3,230,777 bases. Genome of N. sedimentimangrovi UE25 harbors phage mediated DNA through horizontal gene exchange from the phages, symbiotic and pathogenic bacteria. Most of the phage genome encodes for hypothetical proteins, protease, and phage assembly proteins. Gene clusters encoding the intrinsic resistance to glycopeptides, isoniazid, rifamycin, elfamycin, macrolide, aminoglycosides, tetracycline and fluoroquinolone were identified into the genome. Since, the strain has been reported for the production of many industrially important thermostable enzymes, therefore, the genomic data of thermostable enzymes might be helpful to employ this species in commercial sectors. Probing genes of multiple thermostable glycoside hydrolase enzymes especially xylanases of N. sedimentimangrovi UE25 showed genetic diversity among the genes and confer the industrial importance of this microorganism. Furthermore, the genome of N. sedimentimangrovi will greatly improve our understanding of its genetics and evolution.
The chemical modification of biopolymer-based materials by grafting synthetic polymers has received considerable attention in recent years, inasmuch as there are wide varieties of monomers available. Nowadays, the most abundant biomacromolecule, cellulose, has attracted considerable attention due to its biodegradable, biocompatible, and renewable characteristics. In this study, the surface of hydrophilic cellulose microfibers was successfully modified by polymerization of hydrophobic polystyrene using atom transfer radical polymerization (ATRP) technique in dispersion medium. In this medium, only the outer surface of the macroinitiator is available for the polymerization, so the grown polymer chains are formed as monolayer on the surface of the macroinitiator. This type of modification not only increases the mechanical properties of the cellulose backbone, but also turns the hydrophilic characteristics of cellulose into hydrophobic state. For this purpose, in the first part of this research, chloroacetylated cellulose was synthesized as macroinitiator. In the second part, the acyl content of the macroinitiator and the degree of substitution, which show the efficiency of the esterification reaction, have been determined by basic hydrolysis of the macroinitiator with KOH and back-titration of the excess alkali with HCl. Finally, the chloroacetylated cellulose was modified by graft copolymerization of styrene using ATRP method. The polystyrene chain growth is confirmed by the atomic force microscopy images.
Ultrasonic treatments (0, 15, 30, 60 and 120 min) were applied to black liquor resulting from organosolv fractionation of olive tree pruning residues (ethanol/water 60/40 v/v, 180 degrees C, 60 min) in order to determine their effect on black liquor components. HPLC analyses of ultrasound-treated liquid fractions demonstrated that ultrasonic irradiation promoted up to 20\% degradation of monosaccharides for 15 min of sonication and an increase of monomeric sugars from 3\% to 16\% due lignin-carbohydrate complex rupture. The quality and purity of the lignin precipitated from sonicated liquors by adding acidified water were assessed. Attenuated-total reflectance infrared spectroscopy (ATR-IR), gel permeation chromatography (GPC) and nuclear magnetic resonance (NMR) confirmed that main lignin structure did not change due sonication, and thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and chemical composition and antioxidant behavior showed purification of lignin samples. These results established sonication as a suitable intensification technology in biorefinery processes. (c) 2012 Elsevier Ltd. All rights reserved.
Biopolymers exhibit unique properties and can be produced from plants' and crops' wastes. Cellulose has been used for the production of sustainable materials, nevertheless due to the difficulty inherent to its extraction, several methods have been studied in order to optimize the process. Therefore, this paper reports the extraction of natural polymers from food sector agro-food wastes, including cellulose, following a green chemistry aproach. The cellulose extracted from pumpkin peel was acetylated and dispersed in a polylactic acid (PLA) matrix. The developed materials were characterized in terms of their structure, morphology and thermal stability. The results demonstrated the efficient chemical modification of cellulose and confirmed its good dispersion within the PLA matrix.
In this study, the effects of six metal ions including Na+, K+, Mg2+, Ca2+, Cu2+ and Fe3+ on hydrolysis of bamboo biomass by diluted hydrochloride acid (HCl) in ionic liquid {[
To overcome the energy demand and environmental issues by applying ecofriendly techniques to produce green energy are getting high attentions in these days. Lignocellulosic materials are the most abundant resource of biomass on earth and these materials have become vital for anaerobic digestion. However, the structure of lignocellulosic materials is difficult to degrade during anaerobic digestion. Physical, thermal, chemical and thermochemical techniques have been widely used for the pretreatment of lignocellulosic materials, which might facilitate the degradation of pretreated lignocellulosic materials during anaerobic digestion. Further, in recent years many updated and advanced techniques have also been developed for the pretreatment of lignocellulosic materials. Therefore, this study systematically summaries the novel techniques and chemicals used for physical, thermal, chemical and thermochemical pretreatments of lignocellulosic materials for the enhancement of anaerobic digestion. In addition, the mechanism, applications, advantages and disadvantages and challenges of each type of the pretreatment have also been identified. Finally, this study will provide new ideas for the development of new pretreatment techniques.
This study investigated microwave-assisted formic acid (MW-FA) pretreatment as a possible way to improve aromatic production from catalytic fast pyrolysis (CFP) of lignocellulosic biomass. Results showed that short duration of MW-FA pretreatment (5-10 min) could effectively disrupt the recalcitrant structure of beech wood and selectively remove its hemicellulose and lignin components. This increased the accessibility of cellulose component of biomass to subsequent thermal conversion in CFP. Consequently, the MW-FA pretreated beech wood produced 14.0-28.3\% higher yields (26.4-29.8 C\%) for valuable aromatic products in CFP than the untreated control (23.2 C\%). In addition, the yields of undesired solid residue (char/coke) decreased from 33.1 C\% for the untreated control to 28.6-29.8 C\% for the MW-FA pretreated samples. These results demonstrate that MW-FA pretreatment can provide an effective way to improve the product distribution from CFP of lignocellulose. (C) 2016 Elsevier Ltd. All rights reserved.
As a non-traditional heating way, microwave irradiation (MWI) has long been used for lignocellulose pretreatment with the advent of commercial microwave oven since the 1970s. MWI pretreatment using MWI as heating source is similar to other pretreatment methods. Although MWI pretreatment solves some problems caused by other pretreatment methods, such as low heating rate and thermal efficiency, uneven heating, it brings some new challenges such as reaction vessel selection and pretreatment process design. Over 30 years of development, researchers have achieved good pretreatment performance with MWI which has been applied gradually from laboratory scale to pilot-scale. It should be noted that MWI pretreatment is facing some problems: high cost of pretreatment, short of large-scale equipment, the non-thermal effects in pretreatment is still controversial. If MWI pretreatment reaction mechanism could be further clarified and large-scale industrialized reactor be designed, MWI pretreatment might be widely used in biorefinery. (C) 2015 Elsevier Ltd. All rights reserved.
In this study, an anaerobic pneumatic mechanical digester (PMD) was designed for the first time to investigate the impact of pneumatic agitator on increasing the bioethanol production and compared with a mechanical digester (MD). Fermentation was performed during an optimized pretreatment and hydrolysis process by RSM (Response Surface Method). Ultrasound optimized points (the time values, the acid concentration, and the biomass load) were 30 min, 1.95\% v/v, and 6\%, and hydrolysis was done within 45 min at the acid concentration of 2.04\% v/v and temperature of 148.4 degrees C. The hydrolysis solutions were poured and the fermentation process took place within 20 days in the PMD and MD. The sampling sequence was every 5 days. According to the results, the PMD could produce bioethanol more than the MD by 27.94\%. Besides, CO, H2S and O2 were measured through fermentation. In PMD, the amount of H2S and O2 was lower than the MD, but then the production of CO in the PMD was meaningfully higher. Finally, by the application of the PMD, the amount of harmful mixtures produced throughout the process can be controlled. It can be said that with the new method designed in this study, it is possible to take an important step in the biorefinery and use the biomass produced in nature in an economical and environmentally friendly way.
In this work, valorization of Paulownia wood (PW) was proposed following several process configurations for biofuels and value-added compounds production. Firstly, autohydrolysis and ethanol-organosolv strategies were assessed separately for the fractionation of PW to enhance the enzymatic digestibility of cellulose. A third strategy focused on a sequential process (autohydrolysis and organosolv) was explored. Two temperatures were selected for the first stage of the combined process. High concentration of oligosaccharides (26.29 g/L) and high concentration of degradation products (17.21 g/L) were obtained at 210 and 230 degrees C, respectively. The solids obtained from both pretreatments were subjected to organosolv delignification (200 degrees C, 3 h and 50\% ethanol) achieving delignification of 58 and 30\% for the autohydrolyzed biomass at 210 degrees C and 230 degrees C, respectively. The combined process resulted in susceptible biomass able to produce 64 g/L of ethanol. Therefore, the strategies explored in this work open the possibility to build a refinery around Paulownia wood.
Due to energy and environmental concerns, biobutanol is gaining increasing attention as an alternative renewable fuel owing to its desirable fuel properties. Biobutanol production from lignocellulosic biomass through acetone-butanol-ethanol (ABE) fermentation has gained much interest globally due to its sustainable supply and non-competitiveness with food, but large-scale fermentative production suffers from low product titres and poor selectivity. This review presents recent developments in lignocellulosic butanol production, including pretreatment and hydrolysis of hemicellulose and cellulose during ABE fermentation. Challenges are discussed, including low concentrations of fermentation sugars, inhibitors, detoxification, and carbon catabolite repression. Some key process improvements are also summarised to guide further research and development towards more profitable and commercially viable butanol fermentation.
Alkaline hydrogen peroxide (AHP) was first introduced in 1984. Its ability to selectively attack carbonyl and ethylene groups is proven to enhance the delignification process of lignocellulosic biomass. The capabilities of AHP in dissociating the recalcitrant matrix of biomass indicate its potential in improving the accessibility of biomass to achieve valorization. In this paper, the background information of AHP and its reaction pathways are provided. Moreover, the recent applications of AHP in biomass processing and biofuel production are discussed by highlighting the effects of AHP in process selectivity and biomass dissolution. This paper also aims to provide some insights on the advantages and disadvantages of utilizing AHP in a pretreatment process. Lastly, a technoeconomic and cost benefit analysis of two scenarios of AHP production are critically reviewed to highlight the feasibility of implementing AHP in large scale production. It was reported that, AHP pretreatments were compatible with wide range of biomass and subsequent enzymatic hydrolysis. Besides, it was found that the application of AHP sequential pretreatment of biomass could increase the production yield of various bio-products such as silica and lignin. On top of that, AHP pretreatment was found to be a mild pretreatment method that promoted inherent safer and greener process. However, the mild operation condition would require a prolonged period to achieve the necessary delignification. Through technoeconomic analysis, the high chemical cost has rendered the installation of recycle stream compulsory to achieve economic feasibility.
Pennisetum hybrid I, II and switchgrass were pretreated with liquid hot water to enhance the release of sugars. The optimum hydrolysis factor for three energy grasses was 5.98, and the total xylose yield was 88.4\%, 98.1\% and 83.6\% for grass I, II and S. It was indicated that the ratio of syringyl and guaiacyl units of lignin played an important role on the hemicellulose hydrolysis in LHW than branch degree, but latter contributed more on the characterization of xylooligomers degree of polymerization. Moreover, the analysis of multi-scale changes of substrate suggested that cellulose crystallinity index and degree of polymerization seemed no direct relationships for increase of enzymatic digestibility. While lignin barrier was the main factor limiting efficiency of sugar release, and Pennisetum hybrid with low lignin content and high sugar recovery was proved to be a prospective plant feedstock for cellulosic ethanol production. (C) 2015 Elsevier Ltd. All rights reserved.
Biochar and magnetic biochar prepared from chrysanthemum waste of the beverage industry are effective adsorbents for the removal of the non-steroidal anti-inflammatory drug, ibuprofen (IBP), from aqueous systems. The development of magnetic biochar using iron chloride, overcame poor separation characteristics from the liquid phase of the powdered biochar after adsorption. Characterisation of biochars was achieved through Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), N-2 adsorption/desorption porosimetry, scanning electron microscopy (SEM), electron dispersive X-ray analysis (EDX), X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometer (VSM), moisture and ash content, bulk density, pH and zero-point charge (pH(pzc)). The specific surface area of non-magnetic and magnetic biochars was 220 and 194 m(2) g(-1), respectively. Adsorption of ibuprofen was optimised with respect to contact time (5-180 min), solution pH (2-12) and initial drug concentration (5-100 mg L-1), with equilibrium being reached in 1 hour, and the maximum ibuprofen removal occurred at pH 2 and 4 for biochar and magnetic biochars, respectively. Investigation of the adsorption kinetics was achieved through application of the pseudo-first order, pseudo-second order, Elovich and intra-particle diffusion models. Adsorption equilibrium was evaluated using Langmuir, Freundlich and Langmuir-Freundlich isotherm models. The adsorption kinetics and isotherms for both biochars are well described by pseudo-second order kinetic and Langmuir-Freundlich isotherm models, respectively, with the maximum adsorption capacity of biochar and magnetic biochar being 167 and 140 mg g(-1), respectively. Chrysanthemum derived non-magnetic and magnetic biochars exhibited significant potential as sustainable adsorbents toward the removal of emerging pharmaceutical pollutants such as ibuprofen from aqueous solution.
Experiments were conducted to determine the effect of lime pre-treatment on the chemical composition and in vitro rumen degradability of date palm leaves (DPL). Lime pre-treatments, with or without oxygen supply, were applied for 1, 2 and 3 weeks at 25 and 40 degrees C. Lime was neutralized by the Calcium-Capturing-by-Carbonation process. Delignification and in vitro rumen gas production were significantly influenced by duration, temperature and oxygen. At 40 degrees C, oxygen presence stimulated more delignification and subsequently increased in vitro rumen degradability. Lime pre-treatment with 0.2 g calcium hydroxide (Ca(OH)(2))/g dry biomass for 3 weeks at 40 degrees C in the presence of oxygen resulted in a 3-fold increase in gas production after 24 h of incubation, compared with untreated biomass. Lime treatment of DPL with aeration resulted in higher lignin removal and subsequent rumen degradability than without aeration. A techno-economic analysis is needed to select the most efficient and economically feasible pre-treatment procedure.
Contamination of groundwater with toxic arsenic (As) has become an emerging health and environmental problem around the world, which has seen significant attention amongst the scientists for development of new sorbents to remediate As-contaminated water. Here, we explored the arsenate (As(V)) and arsenite (As(III)) sorption to natural water melon rind (WMR), xanthated WMR and citric acid-modified WMR in aqueous solutions, and determined potential of the most potent sorbent for As removal in groundwater. Xanthated WMR (X-WMR) showed relatively higher As(V) and As(III) removal than the citric acid modified WMR (CA-WMR) and natural WMR. The maximum As(III) (99\%) and As(V) (98\%) removal was obtained at pH 8.2 and 4.6, respectively, by X-WMR at 4mg L-1 initial As(V) and As(III) concentrations and sorbent dose of 1 g L-1. Langmuir isotherm model best fitted (R-2 of up to 0.96) the data both for As(III) and As(V) sorption to X-WMR. Sorption kinetics of As(V) and As(III) was well described (R-2 of up to 0.99) by the pseudo second-order model on surface of the X-WMR. Thermodynamic investigations revealed that As(V) and As(III) sorption was endothermic and spontaneous. The FTIR spectroscopy depicted the presence of different surface function groups (-OH, -COOH, S-bearing (C=S, S=O and S-S)) which were involved in As(V) and As(III) sequestration on the sorbents examined here. Significantly, X-WMR showed (up to 49\%) greater As(III) and As(V) sorption than that of natural WMR. Our results demonstrated that X-WMR efficiently removed 94\%-100\% (n = 16) of As from As-contaminated drinking well water which possessed detectable concentrations of some anions (e.g., SO4, CO3, HCO3). This study highlights that the X-WMR has potential to remove As, notably As(III), from solutions and drinking water, and might be utilized as a reactive medium for the treatment of As-contaminated water. (C) 2018 Elsevier B.V. All rights reserved.
We used sodium chlorite followed by sodium hydroxide as a two-stage pretreatment of cassava stem for removal of lignin and hemicellulose to obtain a substrate with high cellulose content prior to hydrolysis. Response surface methodology was applied to determine the optimum hydrolysis conditions of two-stage pretreated cassava stem. After pretreatment, the cellulose content of cassava stem increased from 42.10\% to 86.45\%, concomitant with decreases in lignin (87.59\%) and hemicellulose (78.18\%) content. Acid hydrolysis of two-stage pretreated cassava stem under optimum conditions allowed obtaining a hydrolyzate rich in reducing sugar, with a yields up to 67.37\%. Conversely, inhibitors were detected at very low concentrations. The fermentation of the hydrolyzate resulted in an ethanol yield of 22.58 g/100 g substrate corresponding to a theoretical ethanol yield of 84.41\%. The results demonstrate that two-stage pretreatment is effective for improving cellulose hydrolyzability, resulting in high fermentable sugar and low fermentation inhibitor concentrations.
An experimental design was carried out to evaluate the effect of the concentrations of sodium alginate, glutaraldehyde and activated coal on the immobilization of inulinase from Kluyveromyces marxianus NRRL Y-7571. The experimental condition of 20 g/L of sodium alginate, 50 mL/L of glutaraldehyde and 30 g/L of activated coal led to the highest specific activity (2,063.5 U/mg of protein), corresponding to an enhancement of about 26 times compared to the activity of the free enzyme (79.1 U/mg of protein). The effect of pH and temperature on the immobilized enzyme activity was also evaluated, showing optimal activities at pH of 5.5 and 55 A degrees C. The study of storage of immobilized inulinase in different temperatures showed that the extract kept its initial activity after 43 days of storage at 40 and 50 A degrees C and after 138 days of storage either at 4 or 25 A degrees C.
Effects of post-washing {[
Effects of surface modification by carboxyl group on Pb2+ adsorption performances and stability of peanut shell and its extracts (cellulose, lignin, and hemicellulose) were investigated. Stability of the biosorbents was measured by determining organic compound release amount (TOC). Results showed that adsorption capacity of peanut shell and the extract was poor and stability of them was not good enough. Amount of organic compound released from the unmodified sorbents followed the order: cellulose > lignin > peanut shell > hemicellulose. Hemicellulose was the main organic compound release resource for the raw peanut shell. Due to the poor stability of the raw materials, peanut and its extract could not be used directly in the practical waste water treatment. After modification, adsorption capacity of peanut shell, cellulose, lignin, and hemicellulose increased by 4- to 6-folds. Stability of the modified sorbents also increased significantly, and TOC determined for the modified peanut shell, cellulose, and hemicellulose was lower than 4.0 mg L-1 in the optimum pH range from 4.0 to 6.0 even using for 30 days, which was lower than the drinking water standard in China. Modified peanut shell and its extract except for lignin could be used safely in pH ranged from 4.0 to 6.0. Surface modification could improve the adsorption performances and stability of the biosorbents.
In this work, a dilute sulfuric acid pretreatment at mild conditions was employed to fractionate brewer's spent grain (BSG) with the aim of achieving high carbohydrate recovery. A Box-Behnken experimental design was used with temperature (110-130 degrees C), acid concentration (1-3\% w/v) and time (10-40 min) as independent factors, the objective being to determine the best conditions for the release of glucose (following enzymatic hydrolysis of the pretreated solids) along with that of hemicellulosic sugars in the liquors. The optimal pretreatment conditions were found to be 130 degrees C, 1\% H2SO4 and 26 min, which allowed the recovery of 94\% of the sugars in raw BSG. Next, the effect of substrate concentration on the simultaneous saccharification and fermentation (SSF) process of the pretreated solid was studied. Likewise, the fermentability of the resulting prehydrolysate was evaluated with two xylose fermenting microorganisms, Scheffersomyces stipitis and Escherichia coli. The overall proposed BSG bioconversion process yielded 22.9 L bioethanol from 100 kg of dry biomass. (C) 2019 Elsevier Ltd. All rights reserved.
Ramie was subjected to degumming treatment with high-boiling alcohols, which was an innovative way ahead ascribed to organosolv's innate superiorities, namely the capability to dissolve non-cellulosic biomass obtaining separation of high-purity cellulose fibers, as well as green and ease of recovery. In the current research, effects of degumming processes with four sorts of alcohol solvents on the ramie fiber properties {[
A distillation apparatus was used in the pretreatment of white poplar samples with aqueous 1-ethyl-3-methylimidazolium acetate ({[
The cleavage of the C2-C3 bond in the building units of 1 -> 4-linked polysaccharides by periodate formally results in two aldehyde units, which are present in several masked forms. The structural elucidation of such polysaccharide dialdehycles remains a big challenge. Since polysaccharide derivatives are increasingly applied in materials technology, unveiling the exact structure is of utmost importance. To address this issue for xylan, dialdehyde xylan (DAX, oxidation degree of 91.5\%) has been synthesized as water-soluble polymer. The ATR-FTIR spectrum of DAX showed free aldehyde to be absent and exhibited a characteristic absorption at 858 cm(-1) related to hemiacetal groups. By a combination of 1D and 2D NMR techniques, it was confirmed that oxidized xylan is present as poly(2,6-dihydroxy-3-methoxy-5-methyl-3,5-diyl-1,4-dioxane). Based on GPC analysis, the DAX polymer shows a slightly lower molar mass (6.6 kDa) compared to the starting material (7.7 kDa) right after oxidation, and degraded further after one month of storage in 0.1 M NaCl solution (4.3 kDa). The oxidized xylan demonstrated lower thermal stability upon TGA analysis and a greater amount of residual char (20.6\%) compared to the unmodified xylan (13.7\%).
In the transformation of lignocellulosic biomass into simple sugars that are suitable for microbial fermentation to biofuels, the pretreatment process that increases susceptibility to enzymatic hydrolysis is of the utmost importance. Combination of microwave irradiation as heating mode and ionic liquids (ILs) as solvents was employed in the pretreatment of cypress to figure out the hydrolysis characteristics. Three ILs, namely 1-allyl-methylimidazolium chloride ({[
Solid acid catalysts have been recently studied in starch thermo-hydrolysis owing to their high catalytic activity, recyclability, ease to separate and environmental advantages. However, the solid state reaction of effective catalyst and starch molecules requires specific interaction between active sites in catalyst and alpha,1-4 glycosidic bonds in starch. Therefore, in this study catalyst mixed-milling was conducted prior to thermal hydrolysis to enhance glucose production efficiency. The results showed that catalyst mixed milling process (24 h) followed by thermo-hydrolysis at 140 degrees C for 6 h using HA-L-503H gave highest starch conversion of 93.72\% corresponding to 37.45\% glucose yield and 83\% selectivity. From the kinetic study, the rate constant of cassava mash-to-oligomers conversion (k1) using catalyst mixed-milling was 1.77 times higher than ball-milling without adding catalyst. This indicated that mixed-milling solid state reaction with effective catalyst significantly provided complete cassava mash conversion and enhanced selectivity as well as rate of starch depolymerization reaction. (C) 2018 Elsevier Ltd. All rights reserved.
India meets 80\% of its crude oil demands through imports. India has 17.84\% of the global human population; however, it has only 2.4\% of global surface area, and about 30\% of primary energy consumption. Conventional energy reserves are dwindling, and there has been intensive research to find alternatives to fossil fuels. Considering the looming energy challenges, Indian policy makers have taken multiple strategic steps to incorporate renewable energy into India's energy systems. This paper focuses on the Ethanol Blending Programme, and evaluates various sectors and scenarios (across the value chain) to assess the country's preparedness and capacities to meet the blending target. Results show that, under given market conditions, India can achieve only 3\% blending, although the target was 20\% ethanol blending by 2017. Additionally, challenges and weak linkages across the value chain were identified and actions to fast-track programme execution were made. If the recommendations are realized India can achieve the blending target in the coming years.
For the production of the second generation bioethanol, enzymatic saccharification to prepare a high yield of fermentable sugars is an essential step for the conversion of energy from lignocellulose. In this case, a mild two-step pretreatment using anhydrous formic acid and alkaline hydrogen peroxide aqueous solution was developed to fractionate lignocellulose to highly digestible cellulose for enzymatic saccharification as well as value-added lignin. Bamboo was pretreated with anhydrous formic acid at 40-100 degrees C for 4 h and then extracted with alkaline hydrogen peroxide aqueous solution (containing 1\% NaOH and 1\% H2O2) at 80 degrees C for 2 h. The lignin dissolved in anhydrous formic acid was isolated and further treated with the alkaline solution obtained from the pretreatment and then recovered. The produced cellulose residue had a rather high conversion rate of cellulose into glucose (99.36\%) under an enzymatic hydrolysis for 72 h. In addition, the lignin obtained preserved good functionalities, which exhibited great potential to produce liquid fuels, thus implementing the philosophy of biorefinery. The results indicated that the two-step formic acid-alkaline hydrogen peroxide pretreatment effectively broke the recalcitrant nature of lignocellulose, producing a good feedstock for the conversion into energy. (c) 2017 Elsevier Ltd. All rights reserved.
Old corrugated box (OCB) as a raw material was treated using alkali, acetic acid with NaClO and hydrogen peroxide to extract partially purified cellulose microfibers. FTIR and XRD analysis indicates the significant removal of non-cellulosic (lignin and hemicelluloses) content, followed by a notable increase in cellulose purity and crystallinity. Obtained cellulose microfibers (diameter 60-70 mu m) were broken down to cellulose nanofibers (diameter up to 80 nm) using high-pressure homogenizer at 1700-1800 bar pressure consisting of 30 cycles and further characterized by SEM and XRD. Later on, nanocomposite films were prepared and optimized for required citric acid concentration for cross-linking with tamarind seed polysaccharide/guar gum blend by polycondensation reaction. And plasticized by glycerol (0.5\% w/v) with different concentrations of OCB-CNF (0.1-1\% w/v). The cross-link reaction was optimized at 80 degrees C for 3 h in order to confirm the esterification reaction between citric acid, polysaccharide and nanofiber. Increasing characteristic band intensity at around 1731 cm(-1) represents ester bond formation is supported by the FTIR analysis. Rheology reveals the increase in cross-linking density after citric acid cross-link at 0.2\% of OCB-CNF. Improvement in interfacial bonding between nanofiber and matrix results in enhanced tensile strength, barrier property and thermal stability as compared to those of control film. In addition, swelling behavior of OCB-CNF composite films was studied at different pH conditions (pH = 3, 7 and 10), where 0.2\% and 0.5\% OCB-CNFs showed better interaction with the matrix polysaccharide.
Staggering amounts of food waste are being generated in Asia by means of agricultural processing, food transportation and storage, and human food consumption activities. This along with the recent sustainable development goals of food security, environmental protection, and energy efficiency are the key drivers for food waste valorization. The aim of this review is to provide an insight on the latest trends in food waste valorization in Asian countries such as India, Thailand, Singapore, Malaysia and Indonesia. Landfilling, incineration, and composting are the first-generation food waste processing technologies. The advancement of valorisation alternatives to tackle the food waste issue is the focus of this review. Furthermore, a series of examples of key food waste valorization schemes in this Asian region as case studies to demonstrate the advancement in bioconversions in these countries are described. Finally, important legislation aspects for food waste disposal in these Asian countries are also reported. (C) 2017 Elsevier Ltd. All rights reserved.
Reed was pretreated with liquid hot water (LHW) and then subjected to fed-batch semi-simultaneous saccharification and fermentation (S-SSF) to obtain high ethanol concentration and yield. Results show that water-insoluble solid (WIS) produced from reed pretreated at 180 and 210 degrees C could be effectively converted to ethanol by using Saccharomyces cerevisiae. The optimum conditions for bio-ethanol production are as follows: fermentation temperature of 36 degrees C, pH of 4.8 with cellulase loading of 40 filter paper activity units/g oven-dried WIS, and 18 h pre-hydrolysis at 50 degrees C. Approximately 6.4\% (w/v) fed-batch substrate was added after 6 h of the 18 h enzymatic pre-hydrolysis. The highest ethanol concentration of 39.4 g/L was achieved. The conversion of glucan in the WIS to ethanol reached 79.1\% (180 degrees C) and 75.1\% (210 degrees C) respectively. The ethanol yields per kg of oven-dried reed were 283 g/L at 180 degrees C and 244 g/L at 210 degrees C. (C) 2013 Elsevier Ltd. All rights reserved.
In this paper, we produced hemicellulosic hydrolysate from corncob by tetrabutylammonium hydroxide (TBAH) extraction and dilute acid hydrolysis combined, further evaluating the feasibility of the resultant corncob hemicellulosic hydrolysate used in xylitol production by Candida tropicalis. Optimized conditions for corncob hemicellulose extraction by TBAH was obtained via response surface methodology: time of 90 min, temperature of 60 degrees C, liquid/solid ratio of 12 (v/w), and TBAH concentration of 55\%, resulting in a hemicellulose extraction of 80.07\% under these conditions. The FT-IR spectrum of the extracted corncob hemicellulose is consistent with that of birchwood hemicellulose and exhibits specific absorbance of hemicelluloses at 1380, 1168, 1050, and 900 cm(-1). In addition, we found that C. tropicalis can ferment the resulting corncob hemicellulosic hydrolysate with pH adjustment and activated charcoal treatment leading to a high xylitol yield and productivity of 0.77 g/g and 2.45 g/(L h), respectively. (C) 2016 Elsevier Ltd. All rights reserved.
Microwave-heated alkali pretreatment (MAP) was investigated to improve enzymatic digestibility and H-2/CH4 production from water hyacinth. SEM revealed that MAP deconstructed the lignocellulose matrix and swelled the surfaces of water hyacinth. XRD indicated that MAP decreased the crystallinity index from 16.0 to 13.0 because of cellulose amorphisation. FTIR indicated that MAP effectively destroyed the lignin structure and disrupted the crystalline cellulose to reduce crystallinity. The reducing sugar yield of 0.296 g/gTVS was achieved at optimal hydrolysis conditions (microwave temperature = 190 degrees C, time = 10 min, and cellulase dosage = 5 wt\%). The sequentially fermentative hydrogen and methane yields from water hyacinth with MAP and enzymatic hydrolysis were increased to 63.9 and 172.5 mL/gTVS, respectively. The energy conversion efficiency (40.0\%) in the two-stage hydrogen and methane cogeneration was lower than that (49.5\%) in the one-stage methane production (237.4 mL/gTVS) from water hyacinth with MAP and enzymatic hydrolysis. (c) 2015 Elsevier Ltd. All rights reserved.
Suaeda salsa, a herbaceous species widely distributed in Chinese seaside and desert, not only regulates soil environment, but also provides considerable amounts of biomass. In this research, the optimization of dilute acid pretreatment was performed for enzymatic saccharification of S. salsa. Effect of sulfuric acid concentration, liquid-solid ratio and pretreatment time on xylose and glucose yield in the pretreatment and enzymatic hydrolysis stage was studied with single-factor experiment method. Xylose yield and glucose yield reached a maximum of 18.48 g and 25.49 g per 100 g raw material respectively at the pretreatment condition with 2.6\% (w/w) sulfuric acid concentration, 50 min, 8:1 liquid-solid ratio (v/w) and 125 degrees C. The changes in compositions of the pretreated S. salsa were also investigated. And the changes in structures of the pretreated S. salsa were characterized by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. The results revealed that S. salsa was a potential feedstock for bio-ethanol production and high value-added products. (C) 2013 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
Coffee is a relevant agricultural product and one of the most consumed hot beverages globally. To assess the impact of pyrolysis temperatures (400-600 degrees C) and heating rates from 5 to 20 degrees C/min on the biochar production yields and textural characteristics, spent coffee grounds was subjected to slow-pyrolysis in a pilot-scale reactor. Further, complementary spectroscopic and textural analyses were executed to evaluate the impacts of pyrolysis temperatures on the corresponding biochar surface properties including textural characteristics, reactivity, and surface functionalities. The correlation of pyrolysis temperature with change in biochar's surface properties along with CO2 mitigation efficiency is examined. The ultimate analysis, FTIR spectroscopy, C-13 NMR spectroscopy and Raman scattering measurements confirmed an increment in the degree of aromaticity or decomposition of organic complexes in biochar. The development of basic surface functionalities after the thermal treatment was ascertained by XPS and NEXAFS analyses. Based on the surface composition and textural properties, the CO2 adsorption capacity of SCG-600 was assessed under varying adsorption temperatures at ambient pressure employing a fixed-bed reactor. In this investigation, SCG-600 showed a large CO2 uptake of 2.8 mmol/g under a typical post-combustion scenario. CO2 adsorption mechanism followed the pseudo-first-order kinetics and lower activation energy over varying investigated temperatures reveals the binding process is physical in nature. SCG-600 could be proposed as promising biochar that possesses a combination of higher surface area, well-developed microporous structure, heterogeneous and basic surface functional moieties to meet the specific requirements in dynamic CO2 adsorption.
The aim of this work was to bioconvert all sugars in BSG into ethanol using a process scheme that includes the enzymatic hydrolysis of the whole slurry resulting from the pretreatment of BSG with phosphoric and sulfuric acid using previously optimised conditions, followed by the co-fermentation of the mixed sugars. More than 90\% of the sugars in raw BSG were recovered in the pretreatment and the subsequent enzymatic hydrolysis of the whole slurry. The co-fermentation of the enzymatic hydrolysates with Escherichia coli was then compared with that the co-culture of Scheffersomyces stipitis and Saccharomyces cerevisiae, which resulted in lower ethanol production. The co-fermentation strategy with a single microorganism (E. coli) when BSG was pretreated with phosphoric acid resulted into the highest ethanol concentration, 39 g/L, which means that 222 L of ethanol can be obtained from a ton of BSG without detoxification requirements.
In order to minimize waste liquor, save resources, and reduce costs, the effects of alkali recycling and ozone recycling on enzymatic conversion in alkali combined with ozone pretreatment of corn stover and the mechanism were studied. The results showed that as the number of cycles of alkali/ozone filtrate increased, the enzymatic conversion and the loss of reducing sugars showed a downward trend. It was indicated that the ability of alkali to damage lignocellulosic decreased with an increasing number of alkali circulation and the accumulation of lignin degradation products generated during ozonolysis inhibited enzymatic conversion. When the ozone filtrate was recovered and used for hydrolysis directly, the enzymatic conversion rates were basically the same compared with the first self-circulation of ozone filtrate, and no sewage was discharged. In conclusion, the optimal circulating pretreatment was four times alkali circulation and ozone filtrate was used as an enzymolysis liquid directly, and the conversion rates of cellulose and hemicellulose were 85.96\% and 34.26\%, respectively, saving 44\% alkali consumption at the same time. This paper provided the theoretical basis for the development of lignocellulose pretreatment technology with low cost, high efficiency, and high conversion rate.
Pretreatment of lignocellulosic materials is essential for bioconversion because of the various physical and chemical barriers that greatly inhibit their susceptibility to bioprocesses such as hydrolysis and fermentation. The aim of this article is to review some of the most important pretreatment methods developed to date to enhance the conversion of lignocellulosics. Steam explosion, which precludes the treatment of biomass with high-pressure steam under optimal conditions, is presented as the pretreatment method of choice and its mode of action on lignocellulosics is discussed. The optimal pretreatment conditions for a given plant biomass are defined as those in which the best substrate for hydrolysis is obtained with the least amount of soluble sugars lost to side reactions such as dehydration. Therefore, pretreatment optimization results from a compromise between two opposite trends because hemicellulose recovery in acid hydrolysates can only be maximized at lower pretreatment severities, whereas the development of substrate accessibility requires more drastic pretreatment conditions in which sugar losses are inevitable. To account for this heterogeneity, the importance of several process-oriented parameters is discussed in detail, such as the pretreatment temperature, residence time into the steam reactor, use of an acid catalyst, susceptibility of the pretreated biomass to bioconversion, and process design.
Simultaneous liquefaction, saccharification, and fermentation (SLSF) has attracted much attention for the production of bio-based chemicals, including l-lactic acid, due to its high efficiency and low cost. In this study, a lactic acid-producing bacterium with high tolerance of temperature up to 55 degrees C was isolated and characterized as Enterococcus faecalis DUT1805. Various strategies of stepwise controlled temperature were proposed and investigated for glucose utilization. The results indicated that E. faecalis DUT 1805 exhibited an optimal temperature at 50 degrees C, which could achieve temperature compatibility of enzyme, saccharification, and fermentation, and decrease the possibility of contamination by the other microorganisms during the large-scale fermentation. To reduce the cost of raw material and operation for lactic acid production, aging paddy rice with hull (APRH) was used in l-lactic acid production by simultaneous liquefaction, saccharification, and fermentation (SLSF). An open SLSF operation at 50 degrees C and pH 6.5, and 17\% (w/v) solid loading in 5 L bioreactors was demonstrated with the lactic acid titer, yield, and productivity of 73.75 g/L, 87\% to initial starch, and 2.17 g/(L h), respectively.
The present work reveals the potential applicability of banana leaf waste as feedstock for bioethanol production as very less work has been reported on this feedstock. For achieving the same, the performance of crude cellulases of Aspergillus niger JD-11 is explored for saccharification of untreated and pretreated (alkaline, dilute acid and steam) banana leaf waste. Therefore, to determine the best saccharifying conditions, the effects of various parameters such as enzyme loading (5-15 FPU/g), temperature (40-50 degrees C), surfactant addition (0.05-0.15\% Tween 80 and PEG 6000) and substrate concentrations (2-6\%) were studied at 150 rpm and pH 5.0. The crude cellulases yielded maximum reducing sugars (524.83 mg/g) from the dilute acid pretreated banana leaf waste at 45 degrees C, 15 FPU/g enzyme loading and 2\% substrate loading in the presence of 0.15\% PEG 6000 (w/v) as surfactant. The fermentation of enzymatic hydrolysate was carried out using initial reducing sugars concentration of 40 g/L in the medium at pH 5.5, 150 rpm and 30 degrees C for 30 h with the help of Saccharomyces cerevisiae. Ethanol production was estimated at every 6 h and maximum ethanol yield of 0.38 g/g sugar and productivity of 1.28 g/L/h was obtained after 12 h of fermentation of banana leaf waste hydrolysate. Thus, the easily obtained banana leaf waste could be a promising feedstock for bioethanol production.
An attractive operation strategy for the enzymatic hydrolysis of lignocellulosics results from dividing the process into three stages with complementary goals: continuous enzyme adsorption at low-solids loading (5\% w/w) with recycling of the liquid phase; continuous liquefaction at high-solids content (up to 20\% w/w); and, finally, continuous or semicontinuous hydrolysis with supplementation of fresh enzymes. This paper presents a detailed modeling and simulation framework for the aforementioned operation strategies. The limiting micromixing situations of macrofluid and microfluid are used to predict conversions. The adsorption and liquefaction stages are modeled as a continuous stirred tank and a plug flow reactor, respectively. Two alternatives for the third stage are studied: a train of five cascading stirred tanks and a battery of batch reactors in parallel. Simulation results show that glucose concentrations greater than 100 g L-1 could be reached with both of the alternatives for the third stage.
Delignified Arundo donax was sequentially extracted with DMSO, saturated barium hydroxide, and 1.0 M aqueous NaOH solution. The yields of the soluble fractions were 10.2, 6.7, and 10.0\% (w/w), respectively, of the dry Arundo donax materials. The DMSO-, Ba(OH)(2)- and NaOH-soluble hemicellulosic fractions were further fractionated into two subfractions by gradient 50\% and 80\% saturation ammonium sulfate precipitation, respectively. Monosaccharide, molecular weight, FT-IR, and 1D (H-1 and C-13) and 2D (HSQC) NMR analysis revealed the differences in structural characteristics and physicochemical properties among the subfractions. The subfractions precipitated with 50\% saturation ammonium sulfate had lower arabinose/xylose and glucuronic acid/xylose ratios but had higher molecular weight than those of the subfractions precipitated by 80\% saturation ammonium sulfate. FT-IR and NMR analysis revealed that the highly acetylated DMSO-soluble hemicellulosic subfraction (H-D50) could be precipitated with a relatively lower concentration of 50\% saturated ammonium sulfate, and thus the gradient ammonium sulfate precipitation technique could discriminate acetyl and non-acetyl hemicelluloses. It was found that the DMSO-soluble subfraction H-D50 precipitated by 50\% saturated ammonium sulfate mainly consisted of poorly substituted O-acetyl arabino-4-O-methylglucurono xylan with terminal units of arabinose linked on position 3 of xylose, 4-O-methylglucuronic acid residues linked on position 2 of the xylan bone, and the acetyl groups (degree of acetylation, 37\%) linked on position 2 or 3. The DMSO-soluble subfraction H-D80 precipitated by 80\% saturated ammonium sulfate was mainly composed of highly substituted arabino-4-O-methylglucurono xylan and beta-D-glucan.
In this study, carboxymethylated beechwood xylan was produced under alkali conditions using sodium chloroacetate. Taguchi orthogonal design was used to explore the influence of the process parameters, i.e. NaOH concentration, time, temperature, the molar ratio of sodium chloroacetate to xylan and the concentration of the reaction medium on the charge density and degree of substitution (DS) of xylan. Carboxymethylated xylan (CMX) with the maximum charge density of 1.62 meq/g and DS of 0.21 was produced under the optimal conditions of 0.75M NaOH concentration, 1.0 mol/mol sodium chloroacetate (SCA)/xylan ratio, 2 h reaction time, 70 degrees C and 15 g/L xylan concentration. The carboxylate group of the product was 1.48 mmol/g. The attachment of the carboxymethylated group to xylan was confirmed by Fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (H-1 NMR) spectroscopy. The molecular weight of xylan increased and its thermal stability was improved via carboxymethylation. The dispersion performance of the carboxymethylated xylan in clay suspensions was determined by photometric dispersion analyzer (PDA). CMX showed better performance than sodium carbonate-polyacrylic acid (Na2CO3-PAA) in dispersing the clay suspension. The unmodified xylan did not show any dispersion performance. (C) 2016 Elsevier Ltd. All rights reserved.
Lignocellulosic ethanol is a promising alternative to fossil-derived fuels because lignocellulosic biomass is abundant, cheap and its use is environmentally friendly. However, the high costs of feedstock supply and the expensive processing requirements of lignocellulosic biomass hinder the development of the lignocellulosic biorefinery. Lignocellulosic ethanol production so far, has been based mainly on single feedstocks while the use of mixed feedstocks has been poorly explored. Previous studies from alternative applications of mixed lignocellulosic biomass (MLB) have shown that their use can bring about significant cost savings when compared to single feedstocks. Although laboratory-scale evaluations have demonstrated that mixed feedstocks give comparable or even higher ethanol yields compared to single feedstocks, more empirical studies are needed to establish the possibility of achieving significant cost savings in terms of pre-biorefinery logistics. In this review, some potential benefits of the use of MLB for ethanol production are highlighted. Some anticipated limitations of this approach have been identified and ways to surmount them have been suggested. The outlook for ethanol production from MLB is promising provided that revolutionary measures are taken to ensure the sustainability of the industry.
Succinic acid (SA) is one of the most important biobuilding blocks in biorefinery. Its production from fermentation of renewable biomass sources is becoming a consolidated alternative that is more sustainable and potentially more economic than the traditional petroleum-based path for SA production. Fermentative production of SA has been successfully commercialized and a large and increasing number of SA-derivatives are promoting the economic stability of this production. However, the companies producing SA from fermentation are targeting specialized markets and the production is far from large-scale bulk chemical synthesis. In order to develop optimized and economic processes, the best candidates in every step of the SA production process must be identified. In this paper, the most promising biomass sources, pretreatment methods, fermentation conditions (i.e. host microorganism, fermenter design and operative mode) and separation techniques for industrial SA production are critically reviewed. Selection of the host microorganism is a key factor for SA production. However, the availability, potential and sustainability of feedstocks, fermentation and separation process must also be carefully evaluated for a cost-effective and environmentally sustainable SA production.
In this study, the effects and mechanism of pretreatments of three types of chemical reagents combined with Fenton on poplar sawdust were studied and the optimization of enzymatic hydrolysis conditions was conducted using response surface methodology. The results showed that cellulase and hemicellulase had the best hydrolysis effect after NaOH-Fenton pretreatment, which were 63.73\% and 29.29\%, respectively. The optimal process of poplar substrate was to react in 1\% NaOH at 100 celcius for 1 h, then placed in the Fenton reaction system of 0.2 mmol Fe2+ and 25 mmol H2O2 for 7 h, and finally subjected to enzymatic hydrolysis for 72 h at 52 celcius, with a liquid-to-solid ratio of 33 wt/vol and 15 mu L/g of beta-glycosidase. Under this condition, the enzymatic hydrolysis rates of cellulase and hemicellulase reached 86.65\% and 43.90\%, respectively. In conclusion, the combination of NaOH and Fenton pretreatment can effectively promote the enzymatic hydrolysis of poplar sawdust, which has great potential in the production of cellulosic ethanol.
To replace Pinus taeda wood particles in particleboard manufacturing, thermally treated rice husk was studied, a little-valued raw material, renewable and abundant. This study aimed to evaluate the effect of the addition of thermally treated rice husk on the physical and mechanical properties and resistance to dry-wood termites (Cryptotermes brevis) of particleboard. For the thermal treatment, three mixing proportions of thermally treated rice husk (10\%, 20\% and 30\%), plus the control consisting of 100\% natural pine particles, were used. The thermal treatment was carried out at a temperature of 150 degrees C during two hours. The particleboard was manufactured by compression molding and using phenol-formaldehyde adhesive. The results show that the increase in thermally treated rice husk has no effect on the physical properties of swelling in thickness of the boards; the water absorption parameters after 2 h increased significantly by 7.9\% with the addition of 30\% thermally treated rice husk. The boards met the minimum requirements for static bending of the Brazilian standard, but not for front screw removal. Addition of 30\% thermally treated rice husk improved the biological durability of the boards to dry-wood termites.
Turkey holds a 95\% market share of global sweet bay (Laurus nobilis L.) leaf trade, and it has 25 leaf processing and manufacturing facilities with different capacities. In this study, the usability of waste sweet bay wood (BW) that was removed from bay leaf processing plants was studied. For this purpose, three-layer particleboards were produced by mixing industrial chips (IC) and waste sweet bay wood chips (BWC) at a mixture rate of 0\%, 25\%, 50\%, 75\%, and 100\%. For panel production, urea formaldehyde adhesive (UF) was used in 10\% of the surface layers and in 8\% of the middle layer based on dry chip weight. Some mechanical properties, such as bending strength (BS), modulus of elasticity in bending (MOE), internal bond strength (IB) of the test panels, thickness swelling (TS), and water absorption (WA) amounts, were determined. The results showed that all panel groups except group C (25\% BWC + 75\% IC) met the general purpose panel class (P1) requirements for use in dry conditions according to TS EN 312 (2012). In addition, group A panels (100\% BWC) met the requirements of P2 class for the MOE and BS, and group E panels (75\% BWC + 25\% IC) met the P3 standards. The results showed that BWC could be used to produce particleboard for general purposes, including furniture.
Coffee silverskin (CSS) is an agro-food waste obtained in large amount from the roasting phase of green coffee beans. Its potential use as biorefinery feedstock together with other agro-food wastes has been suggested, even though few experimental studies proved the production of bio-commodities at lab-scale from lignocellulosic sugars from CSS. The present work mainly aims at (i) the maximization of the sugar release by CSS pretreatment and hydrolysis; (ii) the fermentation of the CSS hydrolysate in order to produce butanol and succinic acid as bio-commodities having industrial interest. Alkali-pretreated CSS was enzymatically hydrolyzed in glass bottles on a rotary shaker. Biomass loading (5-12.5\%w v(-1)) and cellulase concentration (1-80 FPU gcellulose(-1)) were the operating conditions investigated to maximize the sugar release. Biomass loading at 10\%w v(-1) gave the best results in terms of sugar concentration and sugar yield. Curve fitting of experimental data was performed: increasing of hydrolysis rate and sugar concentration was observed increasing cellulase concentration. Biomass loading at 10\%w v(-1) and enzyme loading at 80 FPU g(cellulose)(-1) were applied to produce the hydrolysate to use as the medium for fermentation tests: the sugars from CSS were the only carbon source. The batch fermentations by Clostridium acetobutylicum DSM 792 and Actinobacillus succinogenes DSM 22257 were characterized in terms of metabolite and sugar conversion. Butanol (2.2gL(-1)) and succinic acid (20.8gL(-1)) were produced, respectively. The results highlight the possibility of using CSS to produce fermentable sugars, solvents, and biochemicals of industrial interest.
The influence of temperature (150-190 degrees C), time (0-20 mm), liquid/solid ratio (6-8) and sulfuric acid concentration (0.1-0.5\%), on the hydrolysis of palm empty fruit bunches (EFBs) was studied and the liquid and solid fractions were analyzed. Polynomial models were found to reproduce the experimental results with errors less than 15\% in most of the cases (except for xylose concentration). Operating conditions of 190 degrees C for 15 min at a liquid/solid ratio of 6 and a sulfuric acid concentration of 0.1\% resulted in the production of 3.12, 4.0, 2.35 and 2.28 g/L of glucose, xylose, arabinose and acetic acid, respectively, starting with 1000 g of EFBs. The yield was 67.96\%. Soda-anthraquinone, ethanol and ethanolamine pulping of the solid fraction provided pulps with brightness values (63.24\%, 28.78\%, 48.76\%), but with poor resistance properties (6.57-8.54 Nm/g for tensile index, 0.38-0.44 k N/g for burst index and 0.96-1.02 mN m(2)/g for tear index). Therefore it is advisable to use the pulps for speciality papers or for bioethanol-production. (C) 2012 Elsevier Ltd. All rights reserved.
Transitioning from gasoline and petroleum-based products to biofuels and green chemicals is a paradigm shift that will lead to the development of the bioeconomy. In this sense, the role of biorefineries in countries like Brazil is very important as the country generates a huge amount of second generation (2G) biomass every year and also has an attractive consumable market. However, technological innovations are still required to unleash the fullest potential of biomass conversion to biofuels and biochemicals, although successful examples are already a reality. For example, Amyris Inc. has developed renewable products for cosmetics (squalene), healthcare (artemisinin), and flavors / fragrances, and Suzano Papel e Celulose has developed sustainable technologies for the production of pulp and paper, and lignin-derived adhesives (Ecolig). First-generation ethanol in Brazil is an established source of transportation fuel but 2G ethanol production with low production costs is still a challenge at commercial scale, and companies like Raizen and GranBio continue making efforts to improve the economic feasibility of the adopted processes. In this context, the RenovaBio Policy launched by the Federal Brazilian Government in December 2017 aims to boost the production and utilization of biofuels and green chemicals in the country. Considering the matters mentioned above, this paper discusses the Brazilian biorefinery developments, technological advances, and current industrial scenario for the production of biofuels and chemicals. (c) 2021 Society of Industrial Chemistry and John Wiley \& Sons Ltd.
Levulinic acid (LA) is a versatile platform chemical that can be derived from biomass as an alternative to fossil fuel resources. Herein, the optimization of LA production from glucose and oil palm fronds (OPF) catalyzed by an acidic ionic liquid; 1-sulfonic acid-3-methyl imidazolium tetrachloroferrate ({[
One of the main goals of industrial biotechnology is to develop an effective method for ethanol production for fuel purposes using lignocellulosic biomass. Variability of lignocellulosic raw materials, selection of an effective method for the pretreatment of raw material, and selection of microorganisms with the ability to ferment not only hexoses but also pentoses and are moreover resistant to environmental stress generated by the products of lignocellulosic complex decomposition, are the challenges encountered in ethanol production. The use of agricultural wastelands and overgrowing plants that have little possibility of application in processes other than energy production seem to be an interesting alternative to conventional, but very often rather cultivation demanding energy crops. The aim of this study was to evaluate the possibility of using the stems of fireweed (Epilobium angustifolium L.), European goldenrod (Solidago virgaurea L.), and common broom (Cytisus scoparius L.) for ethanol production. The key elements studied were characteristics of the lignocellulosic complex structure, influence of the selected ionic liquids on the structural changes in biomass, and efficiency of enzymatic hydrolysis and ethanol fermentation processes. The results showed that under the assumed conditions the best effect was observed with the fireweed materials subjected to pretreatment with 1-ethyl-3-methylimidazolium acetate and enzymatic hydrolysis with Viscozyme (R) preparation. The final concentration of ethanol obtained was 2.509 g L-1 with a yield of 92.3\%. This was due to the highest share of cellulose (40.9\%) in the whole lignocellulosic complex compared to other raw materials, which in combination with the selection of an appropriate ionic liquid and an enzymatic preparation, led to high bioprocess efficiency.
This study aimed to establish a mathematical modeling to evaluate the inhibitory effect of phenolic derivatives on acetone-butanol-ethanol (ABE) fermentation by Clostridium saccharoperbutylacetonicum N1-4. Vanillin, 4-hydroxybenzoic acid, and syringaldehyde were selected to represent guaiacyl, hydroxyphenyl, and syringyl phenols, respectively, to be examined in a series of fed-batch experiments. Results show the presence of phenolic derivatives blocked the pathway of the assimilation of organic acids and reduced cell growth and glucose utilization. The inhibition model projected that the levels of 0.13, 0.14, and 0.04 g L-1 for vanillin, 4-hydroxybenzoic acid, and syringaldehyde, respectively, resulted in 25\% inhibition of butanol production, whereas 100\% inhibition was predicted at the levels of 4.94, 4.37, and 4.20 g L-1 for vanillin, 4-hydroxybenzoic acid, and syringaldehyde, respectively. Syringaldehyde was more toxic than the other two compounds. The established model described that the phenolic compounds derived from different phenyl propane monomers of lignin severely obstructed biobutanol production.
This paper presents a laboratory scale process for production of bioethanol from Parthenium hysterophorus. This process consists of three steps, viz. biomass pretreatment, enzymatic hydrolysis of pretreated biomass and fermentation of pentose and hexose hydrolyzates obtained from acid pretreatment and enzyme hydrolysis, respectively. The step of enzyme hydrolysis has been optimized using response surface methodology for concentrations of the enzymes and the concentration of biomass. The optimum parameters were: biomass concentration =4.212\% (w/v), cellulase concentration = 135.86 FPU/g substrate and cellobiase concentration = 7511/g substrate. Use of ultrasound during enzymatic hydrolysis at optimized conditions resulted in a marked 18-fold enhancement in the kinetics of hydrolysis. Fermentation of the pentose hydrolyzate with Candida shehatae NCIM 3500 resulted to ethanol yield of 0.069 g/g raw biomass, while fermentation of the enzymatic hydrolyzate with Saccharomyces cerevisiae MTCC 170 resulted to an ethanol yield of 0.187 g/g raw biomass. The total ethanol yield from fermentation of pentose and hexose hydrolyzates was 0.26 g/g raw biomass. This process also provides a potential solution to effective utilization of the noxious waste biomass of P. hysterophorus. (C) 2015 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
Residues of Cistus ladanifer obtained after commercial steam distillation for essential oil production were evaluated to produce cellulose enriched solids and added-value lignin-derived compounds. The delignification of extracted (CLRext) and extracted and hydrothermally pretreated biomass (CLRtreat) was studied using two organosolv processes, ethanol/water mixtures (EO), and alkali-catalyzed glycerol (AGO), and by an alkali (sodium hydroxide) process (ASP) under different reaction conditions. The phenolic composition of soluble lignin was determined by capillary zone electrophoresis and by Py-GC/MS, which was also used to establish the monomeric composition of both the delignified solids and isolated lignin. The enzymatic saccharification of the delignified solids was also evaluated. The ASP (4\% NaOH, 2 h) lead to both the highest delignification and enzymatic saccharification (87\% and 79\%, respectively). A delignification of 76\% and enzymatic hydrolysis yields of 72\% were obtained for AGO (4\% NaOH) while EO processes led to lower delignification (maximum lignin removal 29\%). The residual lignin in the delignified solids were enriched in G- and H-units, with S-units being preferentially removed. The main phenolics present in the ASP and AGO liquors were vanillic acid and epicatechin, while gallic acid was the main phenolic in the EO liquors. The results showed that C. ladanifer residues can be a biomass source for the production of lignin-derivatives and glucan-rich solids to be further used in bioconversion processes.
The aim of this study was to evaluate the effect of the enzymatic extract (EnzE) of native fungus Trametes maxima CU1 on the productive parameters and carcass yield of rabbits. A total of 36 rabbits, 18 New Zealand and 18 California breeds were distributed randomly into two treatments: control (without EnzE supplementation) and EnzE2.5 (with 2.5\% of enzymatic extract added to drinking water). All rabbits were fed with a commercial diet ad libitum. At 49, 71, and 91 d, data for body weight (BW), average daily feed intake (ADFI), feed efficiency, and average daily gain were collected. Moreover, dressing out percentage (DoP) and carcass fat yield (\%CFY) were estimated. BW and ADFI were not different between treatments (P > 0.05). However, rabbits supplemented with EnzE2.5 showed higher values than the control. Rabbits EnzE2.5 and New Zealand males showed the best productive efficiency at 49 d (P < 0.05). On the other hand, EnzE2.5 showed greater DoP than control; furthermore, EnzE2.5 did not show any effect over \%CFY. These results show the potential of T. maxima CU1 as a source of lignocellulases and amylases for the improvement of productive behavior and carcasses yield.
Carbohydrates from hydrolyzed biomass has been a potential feedstock for fermentative hydrogen production. In this study, oil palm empty fruit bunch (OPEFB) was treated by sulfuric acid in different concentrations at 120 degrees C for 15 min in the autoclave. The optimal condition for pretreatment was obtained when OPEFB was hydrolyzing at 6\% (w/v) sulfuric acid concentration, which gave the highest total sugar of 26.89 g/L and 78.51\% of sugar production yield. However, the best conversion efficiency of OPEFB pretreatment was 39.47 at sulfuric acid concentration of 4\%. A series of batch fermentation were performed to determine the effect of pH in fermentation media and the potential of this prehydrolysate was used as a substrate for fermentative hydrogen production under optimum pretreatment conditions. The prehydrolysate of OPEFB was efficiently converted to hydrogen via fermentation by acclimatized mixed consortia. The maximum hydrogen production was 690 mL H-2 L-1 medium, which corresponded to the yield of 1.98 molH(2)/mol(xylose) achieved at pH 5.5 with initial total sugar concentration of 5 g/L. Therefore, the results implied that OPEFB prehydrolysate is prospective substrate for efficient fermentative hydrogen conducted at low controlled pH. No methane gas was detected throughout the fermentation. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
The combination pretreatment strategy is an effective way to intensify photo-fermentative biohydrogen production (PFHP) process. In this study, the synergistic effects of microwave irradiation and surfactants on the hydrogen production performance, energy analysis and structural characteristics was evaluated. Results revealed that hydrogen production performance was improved after microwave irradiation pretreatment (MIP) and surfactants assisted microwave irradiation pretreatment (SMIP). SMIP group had a higher cumulative hydrogen yield (CHY) of 367.87 +/- 6.481 mL compared with control group (223.26 +/- 4.329 mL) and MIP group (303.66 +/- 3.366 mL), which was an increase of 36.01\% and 64.77\%, respectively. Energy evaluation analysis showed that the energy ratio of SMIP (0.49) was higher than that of MIP (0.37) in the PFHP system, therefore, SMIP can save more energy. After SMIP, the corncob lignocellulose structure was greatly damaged, which was verified by SEM, FTIR, XRD and XPS analyses.
This study was designed to determine the effects of wood ash on the physical and mechanical properties of fired clay bricks. The clay bricks were fabricated with the addition of 0, 4, 8, 12, and 16\% by weight of wood ash. Strength development of brick was cased by fired at 900, 1000, and 1100 degrees C for 40 min. The experimental results demonstrated that the physical property and strength of the fired clay bricks depend on the wood ash content and firing temperature. Higher wood ash content affected an increase in porosity and water absorption, while the bulk density of the clay bricks was reduced. The compressive strength of the clay bricks increased with an increase in the firing temperature or a decrease in the wood ash amount. The minimum compressive strength of fired clay bricks, in accordance with the ASTM strength requirements, is 17.2 MPa and was satisfied by bricks containing 4\% added wood ash fired at 1000 degrees C and 1100 degrees C, which attained a compressive strength of 17.9 and 19.4 MPa, respectively. The study confirmed that wood ash is a material that can be used to add extra porosity during the production of raw clay bricks.
Actinobacillus succinogenes is a wild-type bacterial strain, isolated from bovine rumen, known as one of the most efficient natural producers of succinic acid. Herein, the factors contributing to the fermentative production of succinic acid by A. succinogenes are reviewed with particular focus on raw materials, culture conditions, significance of carbon dioxide availability and downstream separation and purification. The metabolic potential of this strain is evaluated through discussion of the pathways involved in succinic acid production, genome analysis as well as the development of A. succinogenes mutants. The review also addresses the importance of by-product formation during fermentation that constitutes an important aspect regulating succinic acid production by A. succinogenes. The prospect of integrating succinic acid production in future biorefineries is assessed. (c) 2016 Elsevier B.V. All rights reserved.
The increasing demand for efficient and sustainable solutions in the field of energy storage and water desalination has sparked research in the development of supercapacitors and capacitive deionization (CDI) cells. This study presents a scalable and eco-friendly process for the preparation of N-doped polyhedral macrotube carbon arrays with a multihole cross-sectional profile. These arrays were synthesized from lotus stems (N-ALS) through carbonization at 500 degrees C and activation at 700 degrees C. The resulting material offers a high density of adsorption sites and good conductivity, making it suitable for use as electrodes in both supercapacitors and CDI cells. The N-ALS electrodes exhibit a high specific capacitance of 221.34 F g-1 at a scan rate of 2 mV s-1 and excellent cycling stability, as well as a salt adsorption capacity (SAC) of 26.07 mg g-1 at an applied voltage of 1.4 V and 85 \% retention after 50 desalination-regeneration cycles in CDI cells, outperforming traditional activated carbon electrodes.
Purpose Pea hulls have a significant contribution to agricultural waste and are left unattended. It has a rich nutrient media and may have application in waste utilization. In this investigation, the potential of pea hulls for the production of cellulase has been explored. Methods The effect of H2O2 concentration, agitation speed and harvesting time on cellulase production by Trichoderma reesei QM9414 under submerged fermentation at constant pH of 5.0 and temperature 30 +/- 0.1 degrees C were studied. Results The maximum filter paper (FP) cellulase activity of 0.372 +/- 0.019 U/mL was obtained at 91 h incubation period and 120 rpm agitation speed. Based on the optimized results of fermentation parameters, 120 rpm agitation speed, 5\% H2O2 concentration and 91 h harvesting time was recommended for efficient cellulase production. The effect of harvesting time on protein, reducing sugar and cellulase activity was pre-dominant. The purified cellulase enzyme specific activity was recorded as 13.8 U/mL. Conclusions The results indicate that the production of cellulase from green pea hulls may provide a novel and economical solution for industrial waste disposal.
Concrete is the most widely used construction material obtained after the setting of the mix composed of coarse and fine aggregates, cement and water. The main properties of concrete are determined by the quality and characteristics of aggregates, W/C ratio, and the uniformity of mix compaction. Compressive strength is one of the key characteristics of concrete. Materials used: Portland cement CEM 1 42.5 R, 0/4 fraction sand, 4/16 fraction gravel, biomass combustion fly ash, superplasticizer, and water. Seven batches of specimens were made with different biomass fly ash content: 0\%, 5\%, 10\%, 15\%, 20\%, 25\%, and 30\% (replacing cement in the mix, \%). The following properties of modified concretes were tested: compressive strength, water absorption, density, ultrasonic pulse velocity, porosity (open and closed), and predicted resistance to freezing and thawing cycles. Concrete, where 15\% of cement is replaced with biomass combustion fly ash, has higher density (2360 kg/m(3)), compressive strength after 28 days (38.3 MPa), ultrasonic pulse velocity (4466 m/s), lower water absorption rate (3.72\%) and higher closed porosity (2.54\%). All these characteristics improve the freeze-thaw resistance of concrete. The tests revealed that concrete modified with 15\% of biomass fly ash had better durability and freeze-thaw resistance characteristics and can be used in construction works. The obtained linear regression equations illustrate the relationships between the density, compressive strength after 28 days of curing, ultrasonic pulse velocity after 28 days of curing, and predicted freeze-thaw resistance of modified concrete. (C) 2018 Elsevier Ltd. All rights reserved.
Microwave (MW)-assisted acid hydrolysis of lignocellulosic material derived from bode (Styrax tonkinensis) wood to glucose was performed to find effective uses for discarded chopsticks. The maximum amount of glucose produced by MW-assisted acid hydrolysis (from 1g of untreated bode wood cellulose) was 0.48g, and was obtained by heating at 200 degrees C for 1min using 1.0\% (w/w) sulfuric acid as catalyst. However, the maximum total glucose yield from both MW-assisted acid hydrolysis (0.16g) and enzymatic hydrolysis of the treated residue (0.52g) was 0.68g, which was obtained at a microwave heating temperature of 180 degrees C for 5min using 1.0\% (w/w) sulfuric acid as catalyst. In conclusion, the results showed that microwave-assisted treatment at 200 degrees C using 1.0\% (w/w) sulfuric acid as catalyst facilitated MW-assisted acid hydrolysis of bode wood cellulose and treatment at 180 degrees C served as pretreatment for enzymatic hydrolysis of the treated residue.
Generation and availability of agro-industrial waste in the world present an opportunity to obtain raw materials for the development of new sustainable materials. In order to contribute to the dissemination of using agro-industrial residues in lignocellulosic particleboard (eco-particleboard) manufacturing, this work aimed to investigate the influence of a chemical mercerization treatment on the physical and mechanical properties of eco-particleboards. The treatment consisted of 0.5\% sodium hydroxide (NaOH). Results of analysis of variance (ANOVA) revealed that treating the fibers was responsible for significantly reducing water absorption by 35\% (2 h) and 17\% (24 h), as well as thickness swelling by 36\% (2 h) and 40\% (24 h). The apparent density of treated (WT) and untreated (UT) eco-particleboards showed homogeneity and uniformity of the test specimens analyzed, mainly due to the manufacturing process in eco-particleboard pressing. The efficiency of the chemical mercerization treatment of the fibers of acai fruit eco-particleboard (WT) was established because the eco-particleboard produced with these fibers showed higher values in their mechanical properties: screw pullout (top) 54\%, modulus of rupture in static bending (31\%), and internal bonding (89\%) compared to eco-particleboards composed of untreated fibers (UT). The physical-mechanical results presented by the eco-particleboards composed of treated acai fibers (WT) suggest that acai fibers could be a potentially useful raw material for the production of medium density homogeneous particleboards and consequent commercial use in the construction and furniture industries.
Several feedstocks for anaerobic digestion (AD) have challenges that hamper the success of AD with their low accessible surface area, biomass recalcitrance, and the presence of natural inhibitors. This paper presents different types of pretreatment to address those individual challenges and how they contribute to facilitate AD. Organosolv and ionic liquid pretreatments are effective to remove lignin without a significant defect on lignin structures. To deal with accessible surface area and crystallinity, comminution, steam explosion, pretreatment using N-methyl-morpholine-N-oxide methods are suggested. Moreover, solid extraction, simple aeration, and biological treatments are capable in removing natural inhibitors. Up to date, methods like comminution, thermal process, and grinding are more preferable to be scaled-up.
Waste-activated sludge (WAS) is a common renewable biomass resource rich in organics. In this study, microwave hydrothermal treatment (MHT) was used to produce 5-hydroxymethylfurfural (HMF) from WAS. The key MHT process parameters of holding temperature, holding time, and pH value were optimized by a Box-Behnken design and response surface methodology. The highest HMF yield (1.58\%) was obtained with a holding temperature of 225 degrees C, holding time of 5 min, and pH value of 1.7. Economic evaluation showed that a profit of \$4640 can be made from one ton of WAS by HMF production. This economical and feasible waste recycling method can produce HMF from WAS with considerable output under suitable MHT conditions and provides a new concept for WAS valorization.
Solid culture with small amounts of low-quality raw coffee beans was used for total petroleum hydrocarbon (TPH) removal from a weathered and polluted soil. Soil contaminated with 58 000 mg kg(-1) of TPH was treated with soil:coffee bean ratios of 98:2, 96:4, 94:6, and 92:8, at a C:N:P ratio of 100:10:1, 20\% humidity, and 28 degrees C, for periods of 15, 60, and 90 days. The highest TPH removal (63\%) was obtained with a soil/bean ratio of 98:2 over 15 days, corresponding with the highest rates of microbial respiration and the greatest increases in bacterial and fungal counts to 9 lnCFU and 6 InCFU, respectively. Scanning electron microscopy showed high fungal colonization of coffee beans, with Mucor sp., Aspergillus sp., Aspergillus niger., and Penicillium sp. growing on TPH as sole carbon source. (C) 2006 Published by Elsevier Ltd.
Altering recalcitrant structures of bamboo is essential to obtain high yield of bioethanol via bioconversion process. With the goal of improving cell wall digestibility, alkaline liquid hot water was used to pretreat N. affinis. The effects of temperature and alkali dosage on structural alterations were determined by chemical composition, Brunauer Emmett Teller (BET) and gel permeation chromatography (GPC). The relationship between these changes and substrate digestibility was addressed by separate enzymatic hydrolysis and fermentation (SHF). The results indicated that pretreatments partly removed and degraded hemicelluloses and lignin, reducing yields of substrates and molecular weights of carbohydrates. With the change of cell wall structure, specific surface area of materials increased after LHW pretreatment but decreased with further removal of lignin and hemicellulosic fractions. Maximum bioconversion was obtained by pretreatment with 0.5\% NaOH aqueous at 170 degrees C and SHF, yielding 4.8 g/L ethanol.
Degradation of lignin from lignocellulosic biomass plays a main key role in converting of lignocelluloses to bioethanol. The pretreatment of lignocelluloses is needed to enhance the fermentable sugars production from enzymatic hydrolysis. This research studied the effect of dilute sulfuric acid pretreatment on the ethanol production using alkaline-dilute acid pretreatment. This research used two stages of the pretreatment process. The first stage used NaOH solution with ratio of rice husk and NaOH solution (1:10 w/v). On the second stage, five concentrations of sulfuric acid of 1 to 5\% at temperature of 121 degrees C and various heating times (30-90 min) were investigated. The ethanol production from pretreated rice husk was conducted by the simultaneous saccharification and fermentation (SSF) for various SSF times of 72-160 hr. The experimental results indicated that an increase in concentration of sulfuric acid capable to destroy the lignocellulosic structure of rice husk. The highest value of cellulose content was achieved about 88.84 \% for acid pretreated material at H2SO4 concentration of 2\% in 90 minutes. The lignin reduction ranged from 47.46\% to 79.29\%. The highest ethanol concentration obtained was 13.68 g/L for the SSF time of 120 hours and the sulfuric acid concentration of 3 \%.
Xylooligosaccharides (XOS) hold industrial importance owing to their prebiotic, antioxidant, antibiotic, and anti-inflammatory potential. The fungal enzyme xylanase (Talaromyces thermophilus F1208) is known for its capacity to produce XOS by hydrolytic degradation. This study aims to achieve the maximum xylan yield through experiments by optimizing corn cob pyrolysate's parameters. The xylan in the pyrolysis solution was converted into XOS using the ultrasonic-coupled enzymolysis method and optimizing its parameters. Optimizing pyrolysis conditions employing maleic acid concentration, pyrolysis temperature, and holding time resulted in a maximum xylan yield (20.04\%) at 0.2\%, 180 degrees C, and 30 min of the three parameters, respectively. The multivariate response surface methodology (RSM) for pyrolysis statistically validated the results and suggested pyrolysis temperature and holding time to be the most crucial parameters influencing the yield. Similarly, the highest yield of XOS (21.75\%) was obtained at 7.5 pH, 4-h reaction time, and 6-U/mL enzyme dosage for the enzyme hydrolysis alone by selecting these three as optimization parameters. In the case of enzyme hydrolysis coupled to ultrasonication, the maximum yield of 27\% XOS was achieved at 190 degrees C pretreatment temperature, 30-min ultrasonication time, 55 degrees C ultrasonication temperature, and 0.31-W/cm(2) ultrasonication frequency, which was similar to 25\% higher than that obtained using enzymatic hydrolysis alone. Moreover, ultrasonic intervention shortened the reaction time to 12.5\% of the original time. The difference in enzymatic hydrolysis of xylan components (H-1-H-5) after alcohol precipitation was also investigated. It was found that the H-2 and H-3 substrates were slow reaction xylans, which were not easy to be enzymatically hydrolyzed.
According to the National Company of Supplying (CONAB) in 2017 alone, the national production of acai pulp reached 219 855 t, equating to 180 million dollar (USD). Almost 85\% of the weight of fruit is constituted by residual biomass, even though researches have highlighted important applications for this biomass, most of it is discarded as organic waste. Thus, it is relevant to en-visage in-depth studies about how to use these residues, particularly regarding the environmental impact of its target destination. Nanocrystalline cellulose (CNC) and lignin are organic derivatives obtained through the physical-chemical treatment of lignocellulosic biomass. Both are abundant and currently considered as biopolymers because of their structural characteristics and their di-verse applications in food and the medical field. This work presents the mass yields achieved and the physical-chemical characteristics of the lignocellulosic derivatives extracted from the fiber of the acai berry. A statistical design was used to define the influence of process variables as tem-perature, reaction time and fiber size on the yield of these byproducts. A maximum yield close to 64\% of type I CNC, with 45\% of crystallinity degree was achieved at the minimum condition of temperature and fiber size. Additionally, through rheological analysis, it was possible to predict the nanocrystal aspect ratios, ranging from 71 to 125. The extracted lignin was rich in methoxy groups, p-coumaryl alcohol and p-coumaric acid, and its structural unit's low state of aggregation can be an indication of low molecular weight, which envisions an appropriate use for this lignin to produce commodity chemicals.
Cellulose nanocrystals (CNCs) have long been an interest of researchers because of their exceptional mechanical properties as well as being sourced from natural, inexpensive, and renewable materials. In this work, maize CNCs (m-CNC) were obtained from maize (Zea mays) husk, which is an agricultural residue. This material is a common waste product from agricultural production in different parts of the world, and of potential value if CNCs with advantageous properties are extracted from them. Maize husk is a major agricultural waste in the United States and is used for erosion prevention or to produce insulating materials, paper, and other chemicals. Dried materials were alkali treated, bleached, and hydrolyzed to CNCs using sulfuric acid. The extracted CNCs were found to have a length of 940 +/- 70 nm and width of 6 +/- 2 nm, high aspect ratio of approximately 157, and increase the Young's modulus of natural rubber composites from 0.89 +/- 0.15 MPa to 1.98 +/- 0.73 MPa with the addition of 2 wt\% m-CNCs. Other characterization techniques employed in this study are dynamic light scattering (DLS), conductometry, thermal gravimetric analysis (TGA), x-ray diffraction (XRD), and optical transmittance. Maize husks provided high aspect ratio cellulose ID CNCs, similar to tunicate CNCs, but with much lower processing required. Therefore, m-CNCs are more cost effective as shown by an economic evaluation. This study could provide assistance for producing CNC from one of the world's largest supply of agricultural waste.
Mulch films increase soil temperature, maintain soil moisture, improve water and fertilizer absorption, and reduce weed growth. This work studied a mulching film made using polyvinyl alcohol (PVA) and lignin extracted from empty fruit bunches (EFBs). The mulch films were investigated for opaqueness, biodegradation, water-solubility, absorption, and mechanical properties. Life cycle assessment (LCA) and cost estimate analysis were conducted. The composite mulch film-PVA solution was blended with 6\% EFB lignin in dimethyl sulfoxide (DMSO) solution using five different amounts (0, 20, 40, 60, or 80 wt\% lignin). The results showed that increasing the amount of lignin increased the film's water solubility, moisture content, and biodegradability. At the same time, water absorption tended to decrease. Consequently, the light transmittance of the film was reduced, which had a positive effect on preventing soil weed growth. Tests of the mechanical properties showed that 60\% lignin in the PVA film had the highest tensile strength (16.293 MPa). According to the LCA studies and cost estimation, the lignin-mixed PVA film had the lowest impact and was cheaper than the commercial mulching film. The results suggested that it is possible to blend polyvinyl alcohol polymer with lignin to improve biodegradability up to 25.47\% by soil burial and 32\% by water solubility.
Adsorption has been considered as one of the most effective methods to remove dyes from aqueous solutions due to its ease of operation, high efficiency and wide adaptability. In view of all these aspects, this study aimed to evaluate the adsorption capacity of a halloysite-magnetite-based composite in the removal of Congo red dye from aqueous solutions. The effects of stirring rate, pH, initial dye concentration and contact time were investigated. The results revealed that the adsorption kinetics followed the pseudo-second-order model, and equilibrium was well represented by the Brunauer-Emmett-Teller isotherm. The thermodynamic data showed that dye adsorption onto the composite was spontaneous and endothermic and occurred by physisorption. Finally, the composite could also be regenerated at least four times by calcination and was shown to be a promising adsorbent for the removal of this dye.
A treatment method producing solid fuel from surgical face masks was developed to address the high cost of medical waste management and the environmental concerns of large-scale, hazardous waste dumping during the coronavirus 19 (COVID-19) pandemic. The fuel properties were investigated of solid fuel produced from surgical face masks (polypropylene material (PP)) and from PP mixed with biomass (composite PP-biomass) using a hydrothermal carbonization process (HTC), followed by pyrolysis using thermogravimetric analysis (TGA). The Coats-Redfern (CR) method was used to analyze the pyrolysis kinetics and thermodynamic parameters. The results demonstrated that the thermal decomposition of raw PP material was less stable than for its hydrochar and the fuel properties of hydrochar obtained from the PP material were substantially improved using an increased HTC temperature. The activation energy value of the raw composite PP-biomass material was higher than for its hydrochar. This research identified an option for a potentially environmental-friendly treatment method for PP-material and its utilization as solid fuel.
In a comparison with certain one-step processes, enzymatic hydrolysis followed by mechanical defibrillation may avoid the use of nonrenewable resources, mitigate the generation of toxic effluents, and reduce the energy consumption related to a single mechanical process. In the present study, bleached and unbleached hardwood pulps were employed as raw materials for producing nanofibrillated cellulose (CNF) using a two-step process, in which a cellulase enzyme was inoculated to act as a pretreatment for a subsequent grinding process. The obtained CNF reached high crystallinity indexes (above 70\%) and high thermal stability (degradation onset temperatures around 200 degrees C). Increases in enzyme concentration yielded decreases in diameter and increases in both thermal stability and crystallinity index. These findings indicated that the enzymatic hydrolysis used as a pretreatment to a further grinding process can allow the production of valuable CNF-based products.
The physicochemical properties of cassava residues subjected to microwave (or steam)-heated acid pretreatment (MHAP or SHAP) were comparatively investigated to improve fermentative hydrogen and methane cogeneration. The hydrogen yield from cassava residues with MHAP and enzymolysis was higher (106.2 mL/g TVS) than that with SHAP and enzymolysis (102.1 mL/g TVS), whereas the subsequent methane yields showed opposite results (75.4 and 93.2 mL/g TVS). Total energy conversion efficiency increased to 24.7\%. Scanning electron microscopy images revealed MHAP generated numerous regular micropores (similar to 6 mu m) and SHAP generated irregular fragments (similar to 23 mu m) in the destroyed lignocellulose matrix. Transmission electron microscopy images showed SHAP generated wider cracks (similar to 0.2 mu m) in delaminated cell walls than MHAP (similar to 0.1 mu m). X-ray diffraction patterns indicated MHAP caused a higher crystallinity index (33.00) than SHAP (25.88), due to the deconstruction of amorphous cellulose. Fourier transform infrared spectroscopy indicated MHAP caused a higher crystallinity coefficient (1.20) than SHAP (1.12). (C) 2014 Elsevier Ltd. All rights reserved.
BACKGROUND: Conventional techniques for corncob hydrolysis were generally based on acid treatment. However, a large number of by-products and undesirable compounds released during acid hydrolysis process may act as inhibitors to xylitol fermentation. To replace acid hydrolysis, SO2-catalyzed hydrolysis was used in this study to improve the fermentability of corncob hemicellulose hydrolysate. RESULTS: Based on a central composite design (CCD), 20 operations were performed to optimize the process of SO2-catalyzed hydrolysis by varying SO2 concentration, temperature and reaction time. The optimum condition found for these parameters was 2.16\%(wt), 142 degrees C, 98 min, with 90.51\% of the theoretical xylose yield obtained. In a comparison with sulfuric acid hydrolysis, SO2-catalyzed hydrolysis was proved to be preferable since it resulted in approximately the same sugar yields, but better fermentability. The conversion of xylose to xylitol and volumetric productivity fermented from concentrated SO2-catalyzed hydrolysate (SCH) were 70.21\% and 1.16 g L-1 h(-1), respectively, higher than those fermented from concentrated sulfuric acid hydrolysate (SAH). CONCLUSION: Findings suggested that the SO2-catalyzed hydrolysis strategy can be conveniently and effectively applied to xylose and xylitol production. (C) 2013 Society of Chemical Industry
Cellulosic ethanol production has received global attention to use as transportation fuels with gasoline blending virtue of carbon benefits and decarbonization. However, due to changing feedstock composition, natural resistance, and a lack of cost-effective pretreatment and downstream processing, contemporary cellulosic ethanol biorefineries are facing major sustainability issues. As a result, we've outlined the global status of present cellulosic ethanol facilities, as well as main roadblocks and technical challenges for sustainable and commercial cellulosic ethanol production. Additionally, the article highlights the technical and non-technical barriers, various R\&D advancements in biomass pretreatment, enzymatic hydrolysis, fermentation strategies that have been deliberated for low-cost sustainable fuel ethanol. Moreover, selection of a low-cost efficient pretreatment method, process simulation, unit integration, state-of-the-art in one pot saccharification and fermentation, system microbiology/ genetic engineering for robust strain development, and comprehensive techno-economic
In the present work, the solid residues of mango stem bark after maceration (MSBAM) were studied as a lignocellulosic material with the potential of serving as a feedstock in the field of bioenergetics. The efficiency of two different chemical pretreatments was evaluated using dilute phosphoric acid and sodium hydroxide. The influence of solid:liquid ratio (w/v), temperature and residence time was assessed on chemical characterization of the pretreated solid fraction of MSBAM. The conversion of glucan to glucose was assessed by enzymatic hydrolysis. Alkaline pretreatment at 120 degrees C, 15 min and solid: liquid ratio (1:10) was the selected condition for obtaining high glucan content. Also, the enzymatic hydrolysis at high-solids loadings was studied. The results of the enzymatic hydrolysis at 21\% showed a glucose production of 71.2 a, which corresponds to 56.3\% of the enzymatic hydrolysis yield. However, at 15\% of solid loading, the glucose concentration obtained was 48.9 g/L and the enzymatic hydrolysis yield was 75.3\%. MSBAM has been considered as a raw material, due to its lignocellulosic structure, susceptible to enzymatic attack for obtaining sugars which, in turn, can be converted into ethanol and other products. Using Scanning Electron Microscopy (SEM), visualization of fibers was done for all the solids pretreated. (C) 2016 Published by Elsevier B.V.
Demand for bioplastic, especially for food packaging, increases as the consumers become more aware of the destructive effect of non-biodegradable plastics. Nanocellulose from banana pseudo-stem has great potential to be formed as a bioplastic. This study aimed to characterize the free-standing film produced from banana pseudo-stem nanocellulose that was prepared by TEMPO-mediated oxidation. The film was found containing calcium oxalate crystals, which most likely influenced the film transparency and possibly affected the contact angle and tensile strength. The film had initial degradation temperature at 205 degrees C, the contact angle of 64.3 degrees, the tensile strength of 59.5 MPa, and elongation of 1.7\%. This initial characterization of free-standing nanocellulose film showed a promising potential of TEMPO-treated nanocellulose from banana pseudo-stem as a source of bioplastic. This study could also be beneficial information for further possible modification to improve the banana pseudo-stem film properties. (C) 2017 Elsevier Ltd. All rights reserved.
Oil palm empty fruit bunch fiber is a lignocellulosic waste from palm oil mills. It is a potential source of xylose which can be used as a raw material for production of xylitol, a high value product. The increasing interest on use of lignocellulosic waste for bioconversion to fuels and chemicals is justifiable as these materials are low cost, renewable and widespread sources of sugars. Batch hydrolysis of oil palm empty fruit bunch fiber was performed at operating temperature 120 degrees C using various concentration of sulfuric acid (2-6\%) and reaction time (0-90 min). Concentration of xylose, glucose, furfural and acetic acid in the resulting hydrolysate were determined. Kinetic parameters of mathematical models were obtained in order to predict concentration of xylose, glucose, furfural, acetic acid in the hydrolysate and to optimize the process. Optimum H2SO4 concentration and reaction time obtained under operating temperature of 120 degrees C was 6\% and 15 min, respectively. Optimum concentration of xylose, glucose, furfural and acetic acid found in the hydrolysate were 29.4, 2.34, 0.87 and 1.25 (g/l), respectively. (c) 2006 Elsevier B.V. All rights reserved.
Torrefaction is a thermal treatment with high potential to be applied in the production of solid fuel from lignocellulosic biomasses. This treatment promotes an increase in the energy quality of the raw material, making it a more attractive and competitive source within the primary energy matrix. However, the production of torrefied biomass on a commercial scale is still at an early stage of development with only a few industrial facilities around the world. Although not one of the pioneering countries in biomass torrefaction, Brazil has a great potential for large-scale deployment in this sector due to its availability of agroforestry biomass in quantity and diversity. The Brazilian agricultural and forestry production is one of the largest in the world with favorable conditions to expand it sustainably. The aim of this study was to evaluate the application potential of torrefaction in the solid fuel's production from lignocellulosic biomasses in Brazil. In the first part, it showed the definitions, use for energy purposes and the Brazilian production of agroforestry biomass. In the second part, it reviewed the definitions of thermal treatments, differences between dry and wet torrefaction process, biomass hydrolysis and torrefaction technologies. In the third part, the challenges and opportunities of the Brazilian commercial torrefaction are discussed.
In this study, we evaluated the capacity of recombinant industrial Saccharomyces cerevisiae YRH 396 and YRH 400 strains to ferment sugars from oat hull and soybean hull hydrolysates into ethanol and xylitol. The strains were genetically modified by chromosomal integration of Pichia stipitis XYL1/XYL2 genes and the overexpression of S. cerevisiae XKS1 genes, in order to have the ability to metabolize xylose, one of the main sugars in lignocellulosic biomass. The strains YRH 396 and YRH 400 were tested by fermenting acid and enzymatic hydrolysates of oat and soybean hull, with different concentrations of sugars, in orbital shaker under conditions of anaerobiosis and oxygen limitation. The YRH 396 strain showed the best kinetic parameters for the production of ethanol and xylitol, thus its metabolism was further studied in bioreactor cultivations. Under anaerobiosis, the maximum consumption of xylose was approximately 35\% when using hydrolysates containing similar concentrations of glucose and xylose, whereas when hydrolysates mainly composed of xylose were used, this strain showed a consumption of 73\% of the xylose, reaching yields of ethanol of 0.33 g g(-1). In bioreactor cultivations under oxygen limitation, xylose consumption reached approximately 65\%, and the main product was xylitol, reaching a final concentration of 8.17 g L-1. These results suggest that, in addition to an adaptive evolution process, molecular modifications are necessary for an industrial application of these type of genetically modified strains.
Paperboard mill sludge (PMS) composed of cellulose, hemicellulose, lignin and ash contents of 36.72 +/- 2.81, 32.91 +/- 1.75, 22.89 +/- 0.56, and 7.48 +/- 0.39\%, respectively. Enzymatic hydrolysis process followed by fermentation of native PMS provided an ethanol yield of 0.36 +/- 0.01 g/L which equivalent to net gain energy of -0.84 +/- 0.03 kJ/g(PMS). Choline acetate ionic liquid {[
This study developed a two-stage organosolv extraction process for the production of diverse components from lea oil fruit hull (TOFH) - a common lignocellulosic byproduct of tea oil processing industry. Results showed that a mild aqueous ethanol organosolv (AEO) extraction isolated 83.8\% of tea saponin and 81.5\% of tannin from the TOFH. Further, a severe atmospheric glycerol organosolv (AGO) extraction recovered the residual tea saponin and tannin. Meantime, the AGO process removed 40\% of the hemicellulose and 35\% of the lignin. The solid residual after the two-stage AEO-AGO extraction had a high cellulose hydrolyzability (>95\%), much higher than that (only 40\%) of one-step AEO extracted solid residual. Structural features of these undissolved solids were characterized by SEM, AFM and FT-IR. The two-stage organosolv extraction showed good potential in biorefining of the agroforestry biomass into value added bioproducts. (C) 2016 Elsevier B.V. All rights reserved.
Hydrothermal conversion normally results in fermentable sugar decomposition and inhibitor accumulation through dissolving and hydrolyzing lignocellulose synchronously. A multilevel hydrothermal process was applied to sequentially dissolve and hydrolyze lignocellulosic waste, and the dissolution mechanisms were investigated. The crystallinity of treated corn stalks increased from 43.1\% to 72.5\% with temperatures increasing from 190 to 220 degrees C and reaction times from 5 to 40 min. FT-IR analysis under these conditions showed gradual hemicellulose disappearance and cellulose retention. For cellulose dissolution, temperatures above 240 degrees C presented significant reductions in crystallinity and degrees of polymerization. Intermolecular and intramolecular H-bonds were broken with the increase in temperature, and glycosidic bonds remained until 260 degrees C. Thus, the amorphous structures of lignin and hemicellulose, as well as crystalline structure of cellulose, could be sequentially dissolved around 190 degrees C and 240 degrees C, respectively. Kinetic analysis revealed that the lignocellulosic dissolution reaction above 190 degrees C did not agree with the surface reaction rate equation because of the high dissolution rate and interaction in the lignocellulosic structure. By contrast, the reaction kinetics of cellulose dissolution did not exhibit a sudden change in the test hydrothermal conditions, and the activation energy was calculated as 189.8 +/- 8.6 KJ mol(-1) according to the obtained reaction rate constants. These findings significantly enhance the understanding of the mechanism, and provide evidence for the sequential dissolution and hydrolysis of lignocellulosic waste using a multilevel hydrothermal process. (C) 2015 Elsevier B.V. All rights reserved.
Xylanses are hydrolytic enzymes with wide applications in several industries like biofuels, paper and pulp, deinking, food, and feed. The present study was aimed at hitting at high yield xylanase producing fungi from natural resources. Two highest xylanase producing fungal isolates-Q12 and Ll were picked from collection of 450 fungal cultures for the utilization of xylan. These fungal isolates-Q12 and L1 were identified basing on ITS gene sequencing analysis as Fusarium sp. BVKT R2 (KT119615) and Fusarium strain BRR R6 (KT119619), respectively with construction of phylogenetic trees. Fusarium sp. BVKT R2 was further optimized for maximum xylanase production and the interaction effects between variables on production of xylanase were studied through response surface methodology. The optimal conditions for maximal production of xylanase were sorbitol 1.5\%, yeast extract 1.5\%, pH of 5.0, Temperature of 32.5 degrees C, and agitation of 175 rpm. Under optimal conditions, the yields of xylanase production by Fusarium sp. BVKT R2 was as high as 4560 U/ml in SmF. Incubation of different lignocellulosic biomasses with crude enzyme of Fusarium sp. BVKT R2 at 37 degrees C for 72 h could achieve about 45\% saccharification. The results suggest that Fusarium sp. BVKT R2 has potential applications in saccharification process of biomass.
Cotton microdust (CMD) was pretreated by a two-stage alkali-acid pretreatment and subsequently subjected to high solids loading enzymatic hydrolysis (HSLEH) and fermentation. The efficiency of the HSLEH of pretreated CMD was enhanced by optimizing the pretreatment condition using central composite design (CCD) and further improvement of enzymatic hydrolysis was facilitated by the addition of surfactant polyethylene glycol (PEG). The predicted optimized pretreatment conditions for maximum digestibility of cellulose from the regression model were 0.8 \% (w/v) H2SO4 and 163 degrees C. The pretreated CMD was efficiently hydrolyzed at high solids loading (35 \%) to produce high glucose concentration. When PEG was added to the HSLEH mixture with a lower cellulase loading of 22 FPU/g glucan, the concentration of glucose produced was 134 g/L. The fermentation of glucose after the surfactant assisted HSLEH at 35 \% solids loading produced 66 g/L of ethanol with 96 \% metabolic yield. The observed levels of reduction of cellulase load and improvement of ethanol production are higher than the reported values for cotton gin wastes. Hence the observed results demonstrated the feasibility of producing high concentration of ethanol from CMD, which would be useful for further improvement and scale-up of the process.
Acacia caesia (L.) Willd (soap bark) fiber is an abundant natural resource, that is rich in cellulose. The study reports the effective utilization of underutilized Acacia caesia fiber for the isolation of nanocellulose whiskers. The nanocellulose whiskers were isolated successfully from Acacia caesia fibers by following alkali, bleaching, and sulfuric acid treatment. The obtained nanocellulose whiskers were carefully investigated for its chemical composition, structure, morphology, crystallinity, and thermal stability. The chemical composition and Fourier transform infrared spectra of nanocellulose whiskers showed the elimination of the non-cellulosic parts present in the raw Acacia caesia fibers. The X-ray diffraction analysis showed an upsurge in the crystallinity of the cellulose fibers after the chemical treatments. The isolation of nanocellulose whiskers from Acacia caesia raw fiber was confirmed by electron microscopy analysis. The thermogravimetric analysis showed remarkably high char residue for the nanocellulose whiskers compared to raw fibers. Based on the properties of nanocellulose whiskers, it can be concluded that the nanocellulose whiskers produced from Acacia caesia raw fibers are potential reinforcing material for developing high-performance green composites.
In this study, sequential biological pretreatment (BP) with Galactomyces sp. CCZU11-1 at 30 degrees C for 3 days and deep eutectic solvent (DES) choline chloride: oxalic acid (ChCl:OA, 1 mol/2 mol) extraction at 120 degrees C for 1.5 h was used for pretreating BSS. It was found that combination pretreatment could effectively remove xylan and lignin for enhancing enzymatic saccharification. The reducing sugars and glucose from the hydrolysis of 100 g/L pretreated BSS with complexed cellulases of Galactomyces sp. CCZU11-1 were obtained in the yields of 81.0\% and 74.1\%, respectively. The BSS-hydrolyzates had no inhibitory effects on the lipid-accumulating microorganism Bacillus sp. CCZU11-1, and the cell mass and TAG accumulation were 4.8 g CDW/L and 2.2 g TAG/L, respectively. Fatty acids including palmitic acid (C16:0; 25.3\%), palmitoleic acid (C16:1; 24.4\%), stearic acid (C18:0; 15.1\%), and oleic acid (C18:1; 21.6\%) were accumulated in cells. Clearly, this combination pretreatment has high potential application in future.
Generation of bioenergy, new functional polymers, or chemicals and biomaterials from hemicelluloses are important uses for biomass. In this paper, a novel functional biopolymer with carbon carbon double bond and carboxyl groups was prepared by a homogeneous esterification of xylan-rich hemicelluloses (XH) with maleic anhydride in 1-butyl-3-methylimidazolium chloride ({[
The aim of this study is to evaluate the potential of some selected biomass waste to be used as feedstock in the production of bioethanol and biohydrogen along with chemicals in Brazil. The substrates are rice bran (RB), rice husk (RH), brewer's spent grain (BSG), soybean waste (SW), and wheat waste (WW). These substrates are treated by diluted acid hydrolysis in an autoclave under different conditions of acid concentration, temperature, reaction time, and moisture. The highest concentration of reducing sugars (RS) of RH, RB, BSG, SW, and WW hydrolysates, measured by the 3,5-dinitrosalicylic acid method (DNS), is 118.16 +/- 2.85, 170.39 +/- 20.47, 600.97 +/- 23.05, 80.38 +/- 2.39, and 228.04 +/- 3.97 g(RS) kg(substrate)(-1) (dry basis), respectively. Total sugar concentration (cellobiose, glucose, xylose, arabinose) in the RH, RB, BSG, SW, and WW hydrolysates (with highest concentration of RS) is 56.54 +/- 3.65, 42.99 +/- 0.84, 72.18 +/- 2.34, 42.48 +/- 0.18, and 78.03 +/- 3.06 g(sugar) kg(substrate)(-1) (dry basis). The total potential of bioethanol and biohydrogen production from the biomass assessed is 199.61 million L per year and 96.14 million m(3) per year, respectively. Therefore, the assessed biomass is proved to be a potential biorefinery feedstock.
Lignocellulosic materials require pretreatment to remove lignin enabling the enzyme access to the cellulose. This work used multivariate analysis to investigate the acid and alkali pretreatments of vine pruning followed by enzymatic hydrolysis. The best acid pretreatment conditions were H2SO4 1.5\%, 120 degrees C for 30 min, removing 68.7\% of hemicellulose, enabling 95.8\% of cellulose recovery. However, this treatment was not enough to allow the enzyme hydrolysis. A second step of treatment with NaOH 3.0\% at 120 degrees C without agitation for 60 min led to a material with 75.0\% of cellulose and 25.0\% of lignin. However, the lowest glucose yield (80.86\% and 32.26 g L-1 of glucose) was obtained after the enzyme hydrolysis of this material. The highest glucose yield (98.72\% with 35.06 g L-1) was obtained using a pretreated material containing 68.1\% of cellulose and 31.9\% of lignin obtained after a milder condition (NaOH 2\% at 100 degrees C), thus showing that not all the lignin need to be removed to obtain a high saccharification yield. A less severe pretreatment with no adverse effect on the glucose yield with the advantage of preserving the non-cellulose biomass fractions was effective for vine prune valorization.
In the present work, coconut shell powder (CSP) is explored as a pore-forming agent in the manufacturing of fired clay bricks. The bricks were produced by varying the amount of CSP (0, 10, 20, and 30 wt\%), and fired at different temperatures (900, 1000, and 1100 degrees C). Mineralogical, physical, mechanical, and thermal conductivity tests were performed to evaluate the properties of the elaborated bricks. It is found that the addition of CSP does not influence the mineralogy of the bricks. Besides, mechanical strength, bulk density, and firing shrinkage increase with sintering temperature and decrease with increasing CSP content, while water absorption and porosity decrease with temperature and increase with CSP addition. Otherwise, the combination of firing at 1100 degrees C with 30 wt\% addition of CSP in clay brick provides lower thermal conductivity (0.37 W/(m.K)), while maintaining adequate tensile strength (9.88 MPa). This finding suggests the reuse of CSP as a pore-forming agent to elaborate bricks with thermal insulating character.
This study explores the possibility of substituting clayey raw materials using ceramic sludge in clay roof tile production. The tile specimens were manufactured in an industrial scale plant by replacing clay with ceramic sludge: 0\%, 10\%, 15\%, 20\% and 25\% (by weight). Strength properties (transverse breaking strength, modulus of rupture, bulk density), durability properties (water absorption, water penetration, salt crystallization, efflorescence, acidic and alkaline resistances) and run-off qualities (Ph, total solids, BOD, heavy metal concentration) were examined. Thermal properties of the sludge incorporated tiles were investigated and compared with the conventional tiles. Bulk density reduces with increasing the sludge content, which is a favorable property of roof tiles. Transverse breaking strength was optimum at 20\% sludge, indicating 22.9\% increment compared to the conventional tile. Clay replacement up to 20\% is acceptable, satisfying water absorption and penetration in standards. No efflorescence and Sulphuric acid attack were disturbed for any specimen. At 12:00 noon, the tile with 20\% sludge reduced indoor temperature by 2.8 degrees C, providing more comfortable shelter compared to the conventional roof tiles. For the 25\% sludge incorporated tiles, run-off showed 120.2 mg/l total solid concentration, 7.36 Ph value and 5 mg/l BOD5 value, 0.01 mg/l, 0.05 mg/l, 0.06 mg/l, 0.04 mg/l Cd, Cu, Pb and Zn concentrations, respectively; while for the other tiles, run-off had lesser concentrations, which are favorable for rain water harvesting process. With 20\% sludge, tiles achieved better structural, durability and thermal properties compared with the conventional tiles while satisfying the standard limits of run-off qualities. (C) 2018 Elsevier Ltd. All rights reserved.
Autohydrolysis of cellulosic materials for saccharification generates xylose-oligosaccharides (XOS), due to the partial hydrolysis of xylan. Developing an efficient method for the separation and recovery of XOS from the prehydrolyzates would provide an excellent opportunity for the better utilization of the cellulosic material and for value-added co-product production. In this study, we investigated the use of centrifugal partition chromatography (CPC) for the fractionation of XOS from Miscanthus x giganteus (M x G). During autohydrolysis of miscanthus biomass at 180 degrees C for 20 min, 63\% of xylan was converted into XOS and xylose. The ensuing XOS concentrate contained up to 30\% of XOS, which were distributed as 15.9\% xylobiose (DP2), 5.9\% xylotriose, (DP3), 5.6\% xylotetraose (DP4), 0.8\% xylopentaose (DP5) and 0.6\% xylohexaose (DP6). The XOS concentrate was further fractionated by CPC with a solvent system composed of 4:1:4 (v/v/v) butanol:methanol:water. Using CPC techniques, 230 mg (80\%) of DP2 to DP6 oligomers were fractionated from 1 g of XOS concentrate. The recoveries of individual XOS were 90.2\% DP2, 64.5\% DP3, 71.2\% DP4, 61.9\% DP5 and 68.9\% DP6. The purities of DP2 to DP6 fractions were 61.9\%, 63.2\%, 44.5\%, 31.5\% and 51.3\%, respectively. Presence of DP2 and DP3 in the CPC purified fractions was further validated by mass spectrometry analysis. The study provided information on fast recovery of individual XOS from crude biomass prehydrolyzate. (C) 2015 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
In this study, beech wood was fractionated in lab scale rector by one-stage and two-stage processes. The two-stage processes of the prehydrolysis with no catalyst (only water) and catalyst (sulfuric, phosphoric, oxalic acids), and the subsequent effect on the organosolv process were studied. A one-stage organosolv delignification of beech wood (control experiment) was conducted at 155 degrees C for 160 min in 1:1 ethanol/water mixture with 100 mM sulfuric acid, while the two-stage processes were conducted starting from the uncatalyzed and catalyzed (20-200 mM) prehydrolysis of beech wood at 175 degrees C for 60 min. The results indicate that sulfuric acid enhanced the removal of xylan from beech wood during the prehydrolysis stage. Moreover, the effectiveness of the delignification of beech wood using a one-stage process is more than the two-stage, as well as the enzymatic digestibility of the pulp, which was better than those of the two-stage processes. However, the enzymatic digestibility results of the pulp obtained after sulfuric acid catalyzed prehydrolysis followed by organosolv delignification shown better results than the other two-stage processes. Additionally, high klason content, low sugar content, low M-w, and high phenolic hydroxyl groups of lignin was recovered by a one-stage organosolv delignification. (C) 2020 Elsevier Ltd. All rights reserved.
Corncobs are a plentiful lignocellulosic material that can be utilized for energy production as well as the generation of other high-value products. Within the modern concept of biorefineries, we present processes conducted in a column reactor for the valorization of corncobs as a substrate for ethanol and xylitol production. In the first step, corncobs were subjected to acid hydrolysis, resulting in a hemicellulosic hydrolysate rich in xylose sugars intended for xylitol production by Candida tropicalis UFMGBX12-a. The Y-P/S (yield coefficient of product to substrate) and Q(P) (productivity) values were approximately 0.2 g/g and 0.15 g/L \& BULL;h, respectively, for the assays conducted in the column reactor. Next, the remaining solid portion of cellulignin was used for ethanol production through semi-simultaneous saccharification and fermentation process by Scheffersomyces parashehatae UFMG-HM 52.2. This approach involved an intensified successive process consisting of alkaline pretreatment of cellulignin, followed by enzymatic hydrolysis and fermentative processes conducted in the same reactor without biomass transfer. After obtaining the enzymatic hydrolysate, a Q(P) value of 0.4 g/L \& BULL;h for ethanol production was observed in the fermentation process conducted in the column reactor. The results demonstrate the potential of corncobs as a carbon source for biomolecules production, utilizing a process conducive to scale-up.
Fucoidan extraction from Kjellmaniella crassifolia was enhanced through beta-glucosidase fortified cellulase treat-ment. Kinetic study of the hydrolysis of isolated seaweed cellulose by commercial enzymes was carried out, and cellulolytic enzyme cocktail was optimized according to the degradation kinetics using response surface meth-odology for fucoidan extraction. Cellulose (9.88 wt\%, d.b.) found in the seaweed was highly crystalline (CrI: 83.24 \%). beta-glucosidase apparently improved the affinity of the cellulolytic enzymes for the cellulose by elimi-nating cellobiose feedback inhibition. Treating the seaweed with 30 FPU cellulase supplemented with 286.64 CBU beta-glucosidase per gram cellulose, followed by conventional ethanol precipitation, the fucoidan extraction yield based on seaweed feedstock dry matter reached 4.74 \%. The total sugar content and sulfate content of the product reached 76.68 \% and 22.83 \%, respectively, with fucose accounting for 62.46 \% of the total sugar. The product extracted under optimal conditions exhibited apparently concentration-dependent antioxidant activity, with IC50 values for DPPH, Hydroxyl and ABTS radical scavenging reaching 2.43 mg/mL, 1.02 mg/mL and 1.12 mg/mL, respectively. The results showed that the proposed enzymatic treatment based on cellulose hy-drolysis kinetics effectively disrupted the cell wall and facilitated the release and extraction of fucoidan from the seaweed.
Herein, we report on a transparent, water-stable, high oxygen barrier packaging film made from a combination of cellulose nanofiber (CNF) and a fluoropolymer (FP) coating. Nanofibrillation of the hardwood kraft pulp was carried out using succinic anhydride pretreatment and aqueous counter collision (ACC) technique to obtain ultrafine (5-7 nm) succinylated cellulose nanofibers (SCNF), which was readily fabricated into a thin coating (on PET film) as well as a self-standing film. Introducing the FP topcoat on SCNF enabled a synergistic enhancement of both oxygen barrier performance and stability against water-swelling.
The purpose of this study was to evaluate steam explosion as a pretreatment to enhance degradation of corn stover by ruminal microbiome. The steam explosion conditions were first optimized, and then the efficacy of steam explosion was evaluated both in vitro and in vivo. Steam explosion altered the physical and chemical structure of corn stover as revealed by scanning electron microscopy (SEM) and Fourier-transform infrared (FTIR) spectroscopy, respectively, and increased its cellulose content while decreasing hemicellulose content. Steam-exploded corn stover also increased release of reducing sugars, rate of fermentation, and production of volatile fatty acids (VFAs) in vitro. The steam explosion treatment increased microbial colonization and in situ degradation of cellulose and hemicellulose of corn stover in the rumen of dairy cows. Steam explosion may be a useful pretreatment of corn stover to improve its nutritional value as forage for cattle, or as feedstock for biofuel production.
Pretreatment is a prerequisite to tackle the issue of biomass recalcitrance, which is the major hindrance of lignocellulose-to-sugars routes. In the present study, a novel combination of dilute sulfuric acid (dilute-H2SO4) with Tween 80 pretreatment of corn stover (CS) was developed to significantly enhance the enzyme digestibility. Strong synergistic effects of H2SO4 and Tween 80 for simultaneously eliminating hemicellulose and lignin and significantly promoting saccharification yield were observed. A response surface optimization realized the maximum monomeric sugar yield of 95.06\% at 120 degrees C for 1.4 h with 0.75 wt\% of H2SO4 and 73.92 wt\% of Tween 80. The excellent enzyme susceptibility of pretreated CS was explained by their physical and chemical characteristics via SEM, XRD, and FITR. The repeatedly recovered pretreatment liquor exerted highly-effective reusability in the subsequent pretreatments for at least four cycles. This strategy offers a highly-efficient and practical pretreatment strategy, which provides valuable information for the lignocellulose-to-sugars routes.
The severe pretreatment of poplar makes xylan difficult to utilize efficiently. In this work, poplar was pretreated by hydrogen peroxide-acetic acid (HPAC) with H2SO4 as catalyst to remove lignin, and the solid residues were used to produce xylooligosaccharides (XOS) and monosaccharides by two-step xylanase and cellulase hydrolysis. The results indicated that higher H2SO4 concentrations in the HPAC pretreatment of poplar afforded stronger lignin removal ability. An increased XOS yield of 19.8\% was obtained from 200 mM H2SO4 -catalyzed poplar by xylanase and the XOS purity was high, with a very low xylose/XOS ratio of 0.14. Higher glucose (75.2\%) and xylose (61.4\%) yields were obtained from the HPAC-pretreated poplar using 50 mM H2SO4 as catalyst. Finally, 16.9 g XOS and 296.4 g glucose were produced from 1 kg poplar by xylanase and cellulase. This study provides a method for producing functional XOS and monosaccharides from poplar using a simple reduced-pollution strategy.
The combination of different pretreatment methods can effectively overcome recalcitrance of lignocellulosic biomass to ensure its highly efficient conversion into bio-based products. In this study, the combined pretreatments of chemical methods (hydrothermal treatment and Fenton treatment) with mechanical refining were used to improve the enzymatic hydrolysis efficiency of poplar branches. The results indicated that hydrothermal pretreatment and Fenton pretreatment can effectively improve the enzymatic hydrolysis of poplar substrates, e.g., the maximum glucose conversion yield and glucose concentration reached 92.4\% and 20.8 g/L, respectively. The pre-hydrolysates contained some valuable components such as monosaccharides, oligosaccharides, acetic acid, furfural, and hydroxymethylfurfural. The main characteristics (specific surface area, water retention value, fines content, and surface lignin concentration) of poplar substrates were obviously changed by the combined pretreatment, which benefit the enzymatic hydrolysis.
This paper investigated the two novel dry strength agents, prepared by chemical modification of hemicelluloses with etherifying agents in different media, for application in recycled fiber based packaging paper and old corrugated container (OCC) pulp. One new dry strength agent possessed cationic groups, whereas the other had anionic groups. It was found that these new dry agents with different DS (degree of substitution) values could clearly improve paper strength of OCC pulp. With the addition of 1.0\% (w/w) cationic type hemicellulosic derivatives with a DS value of 0.5 to OCC pulp, the physical property improvement reached its maximum: the breaking length, burst index, tear index and ring crush index increased by 27.3\%, 51.6\%, 18.5\% and 68.4\%, respectively. Hemicelluloses could, therefore, be used as source material for the production of wet-end additives in the paper industry.
This study investigated high-solid loading deep eutectic solvent (DES) pretreatment for lignocellulose fractionation and subsequent conversion into platform chemicals (i.e., furfural, 2,3-butanediol). Switchgrass was pretreated with choline chloride:ethylene glycol (ChCl:EG) under acidic condition at high solid loadings of 20\% and 27\%. Cellulose was enriched to as high as 72.6\% in pretreated switchgrass due to substantial removal of lignin and xylan but minor cellulose loss. Highly concentrated sugar hydrolysate containing up to 241.2 g/L fermentable sugars (206.5 g/L glucose and 34.7 g/L xylose) with 86.2\% glucose yield was obtained from pretreated switchgrass via 25\% solid loading enzymatic hydrolysis for only 48 h. The high sugar concentration allowed the production of 90.2 g/L 2,3-butanediol upon fermentation, a record high titer produced from lignocellulose hydrolysate without additional sugar concentration. ChCl:EG showed good recyclability, and its reuse facilitated lignin recovery from pretreatment liquor. The pretreatment liquor resulting from four pretreatment cycles was enriched with xylan-based sugars (96.8 g/L xylose equivalents), of which 84.6\% was converted to furfural. 2D HSQC NMR revealed that beta-O-4 interunit linkage experienced substantial cleavage during the pretreatment. The degree of bond cleavage depended on the solid loading for pretreatment. Lignin derived from a higher solid loading pretreatment preserved the original structure of natural lignin better, thus producing increased amounts of phenolic monomers upon pyrolysis. This study demonstrated that high-solid loading, ChCl:EG pretreatment was not only effective for biomass fractionation but also enabled industrially relevant production of concentrated sugar hydrolysate, furfural, and 2,3-butanediol.
Separation-free sugar-platform biorefinery from lignocellulose has drawn increasing attention due to its feasibility. However, the presence of lignin-derived phenolics within the whole slurry after pretreatment, is highly inhibitory toward enzymatic hydrolysis of lignocellulose especially at high solid loadings. Developing effective methods to mitigate the phenolics-caused enzyme inhibition in-situ can further improve the cellulose hydrolysis, while the relevant studies are limited. In this study, the effects of different kinds of additives on mitigating the phenolic-caused inhibition was determined and the synergy among the additives were systematically evaluated. Based on the analysis, we developed novel binary additives to alleviate the phenolic-caused inhibition of cellulose hydrolysis in-situ. In addition to surfactants, a reducing agent (L-cysteine) was introduced to enhance the enzymatic hydrolysis of cellulose and the strong synergism between the reducing agent and the surfactant was firstly demonstrated. Further, the mechanism study indicated that these additives could prevent the strong interactions between phenolics and cellulase and improve the major cellulase activities. Finally, with the addition of the binary additives, the cellulose hydrolysis for acid/alkaline pretreated corn stover were significantly improved with low enzyme loading without detoxification. This study provides directions for designing novel additives to improve the enzymatic hydrolysis of pretreated lignocellulosic biomass.
Varieties of blue maize are used to produce tortillas. The Bolita genotype is frequently underused, despite its rich content of bioactive compounds. The composition of derived products is influenced by maize processing. The impact of processing on the total phenolic content (TPC), phenolic acid profile (PAP), antioxidant activity (AA) and color was evaluated in tortillas produced from blue Bolita landraces. The properties were determined in anatomical fractions, nixtamal, wastewater, masa and tortillas. Vanillic, ferulic, p-coumaric and chlorogenic acids were identified in anatomical fractions. Nejayote had the highest AA. The compounds in the soluble fraction contributed mainly to the AA, whereas the free and bound fractions were largely responsible for the TPC. Syringic and ferulic acids were the most common compounds in the nejayote, and p-coumaric acids were the most common compounds in the masa. Only ferulic acid was detected after simulated gastric digestion, and temperature, pH and milling had an important effect on the PAP.
A novel acylation approach suited to rapid bulk thermoplasticization of lignocellulose without solvents was previously demonstrated by the authors in benchtop batch studies. The method relies upon a benzethonium chloride/sulfuric acid functionalizing agent at low concentrations to act as a wetting agent for the wood pulp, similar to an ionic liquid, yet binds to the lignocellulose ester as a flow aid in the final thermoplastic. The present investigation evaluates the approach in a residence time-limited (45-90 s) continuous twin-screw reactor, where intensive mixing and heat were found to yield high acylation. The modified lignocellulose exhibited desired thermoplasticity by being melt moldable without the need for plasticizers and maintained much of the excellent stiffness of cellulose, demonstrating a maximum flexural modulus of 5.4 GPa and tensile modulus of 1.8 GPa. The influence of extrusion conditions on thermoplasticity was examined by a Design of Experiments (DOE) analysis.
Pre-treatment is one of main economic and technological challenges to render feasible the production of biofuels and chemical compounds from lignocellulosic biomass. Alkaline hydrogen peroxide (AHP) is the most used pre-treatment and recycling of its liquid fraction can help reduce production costs. The effects of four AHP concentrations (1, 3.5, 5 and 7.5\% v/v) on the recycling performance of the liquid fraction of pre-treated corn stover was evaluated for five consecutive cycles. Delignification rates increased with increasing AHP concentrations in the first cycle: 15, 26, 43 and 76\% with 1, 3.5, 5 and 7.5\% v/v H2O2, respectively. In the following cycles, the rates decreased linearly reaching less than 40\% in the last two recycles. These delignification rates and hemicellulose solubilization were corroborated by spectroscopic analyses with Fourier transformation showing reductions in lignin and hemicellulose absorbance and increases in crystallinity indices. Considering the low delignification rates in the last two cycles, the pre-treated biomasses obtained until the third cycle were submitted to enzymatic hydrolysis at 1:10 solid-liquid ratio. The delignification rates affected the efficiency of the enzymatic hydrolysis at all AHP concentrations and all recycles. The highest AHP concentration (7.5\% v/v) was required to efficiently remove lignin and solubilize hemicellulose, maintaining cellulose conversion into glucose greater than 50\% up to three recycles. Therefore, the technology of recycling the liquid solution of AHP pre-treatment is recommended with high initial concentrations (7.5\% v/v). {[
The present study is concerned with the preparation and characterization of highly porous bricks using the carbonation sludge (CS). The characteristics of raw materials were determined by SEM, TGA, XRF and XRD analyses. The clay bricks with CS (0\%, 5\%, 10\%, 20\%, 30\% and 40\% by weight) were pressed, dried and then fired at 1000 degrees C and 1100 degrees C for 2 h. The features of the fired bricks like loss on ignition, dilatometric behavior, water absorption, apparent porosity, bulk density, compressive strength, thermal conductivity and leach analysis were determined. The addition of CS in brick structure is reduced the bulk density of the fired samples. The use of CS up to 40\% has resulted in an increase in porosity values for the samples. It was found that the compressive strengths of the bricks up to 30 wt\% CS addition were in accordance with standards for the fired bricks. A decrease from 0.79 W/mK to 0.26 W/mK was observed in terms of thermal conductivity. The mechanical and physical features of the bricks were affected by the increasing of firing temperature. Based on these findings, the CS may be valorisation as pore-forming additive in the brick production. Therefore, the utilization CS waste in industrial scale reduces the solid waste load of sugar factories and enables sustainable, eco-friendly and cleaner clay brick production. (C) 2019 Elsevier Ltd. All rights reserved.
Agricultural crop residues like stems, straws and leaves are valuable resources for biofuel production, especially methane, due to anaerobic digestion. Biogas from agricultural lignocellulosic wastes is capable of attaining sustainable energy yields without environmental pollution. Farmers in many developing countries burn these wastes throughout their fields, imposing environmental hazard due to emission of greenhouse gases. The main problem in this field is the recalcitrance of the agricultural lignocellulose waste that limits its enzymatic degradation and hydrolysis efficiency and consequently decreases biogas production. Therefore, efficient pre-treatments prior to anaerobic digestion are essential. Various pre-treatment methods are used for increasing the anaerobic digestibility of lignocellulose biomass, such as physical (mechanical, thermal, etc.), chemical, biological and combined pre-treatments. This paper reviews different pre-treatments used in anaerobic digestion for the agricultural lignocellulosic wastes and explains the advantages and disadvantages of each. The most frequently used pre-treatments for main agricultural wastes in process of biogas production are also introduced.
Development of an effective pretreatment method is a vital stage to enhance biomass-based biopolymers production. The present study aims on the pretreatment of wheat waste biomass (WS) with alkaline and in combination with ultrasound (US) treatment to enhance enzymatic saccharification of WS into monomeric sugars. Effects of chemical dosage, substrate loading, US power and US pretreatment time on the pretreatment efficiency were systematically investigated. Under optimized conditions; US + NaOH pretreatment attained maximum 70\% delignification of WS, with 84.5\% hydrolysis yield, 90\% glucose yield and 65\% xylose yield after enzymatic hydrolysis (30 FPU/g of dry WS) which is substantially higher than the individual pretreatment. Analytical studies (XRD, FTIR, and SEM) revealed that the combined US + NaOH pretreatment can effectively destroyed the ultrastructure of biomass and improved the accessibility to hydrolyzing enzymes. The resulted enzymatic hydrolysates were utilized as a possible biomass feedstock for polyhydroxybutyrate (PHB) production using Ralstonia eutropha. Effects of supplementation of nutrients, stressing agents and initial concentration of US + NaOH pretreated WS hydrolysates (20 to 40 g/L) on PHB production were evaluated. The maximum 74\% PHA accumulation, PHB titer of 7.85 g/L and yield of PHB about 0.441 g/g of reducing sugar production was obtained. Analytical characterization and thermal characteristics of extracted biopolymer showed the poperies of standard PHB. The foregoing results suggested the potential of WS as an alternate renewable resource for sustainable biopolymer production and enables WS waste biomass disposal concerns.
In this study, Rhizopus oligosporus MTCC 556 (Rhizopus) treated rice bran was utilized for the anaerobic bacterial fermentative hydrogen production. The Enterobacter aerogenes MTCC 2822 with nutrients addition fermented the treated rice bran to give hydrogen yield of 5.4 mmol H-2/g of biomass. A closely similar hydrogen yield of 4.6 mmol H-2/g of biomass was obtained from the treated rice bran under the condition without nutrients addition, suggesting the potential of the fungus treatment to produce hydrogen from nutrient-free fermentation. The pretreated rice bran showed efficient hydrogen production upon anaerobic fermentation without nutrients addition. The Rhizopus pretreated biomass can provide required nutrients for the enhancement of hydrogen yield by anaerobic fermentation. The Rhizopus pretreatment of rice bran enhanced the hydrogen production under nutrient-free conditions which reduced the overall production cost. The findings provide a promising solution to efficiently utilize the rice bran waste for low cost hydrogen production.
White-rot fungi pretreatment is one of the most environment-friendly pretreatment methods because of low chemical and energy requirement. However, apart from time consuming, white-rot fungi treatment results in inefficient delignification and humin formation, both of which inhibit subsequent enzymatic hydrolysis. Combined alkaline treatment for partial depolymerization of residual lignin and dissolution of humin is an efficient option for the conversion of white-rot pretreated samples. In the work presented, combined treatments increased the enzymatic digestibility to 89.3\%, compared with 10.6\% for untreated sample and 12.9\% for solely white-rot treated samples. Highest digestibility of cellulose was achieved after 8 weeks of white-rot treatment and alkaline treatment at 120 degrees C, whereas sugar yield was highest from sole alkaline treatment at 160 degrees C. The efficient conversion can be ascribed to synergistic interaction between white-rot and alkaline treatments, resulting in increased enzymatic accessibility of cellulose. Therefore, white-rot fungi treatment is a green process that can efficiently decrease energy consumption, and in combination with alkaline treatment is highly effective in promoting sugar conversion. (C) 2016 Elsevier B.V. All rights reserved.
Various pre-treatments (acid, alkaline, enzyme and alkaline aided enzyme also termed combined) were evaluated on different fractions of bamboo waste from a chopstick production factory. Chemical oxygen demand (COD) solubilisation, monomeric/dimeric sugar yield, methane yield enhancement and methane production rate were assessed. The biochemical methane potential was determined in batch assays under mesophilic conditions (37 1 C) using the Automatic Methane Potential Test System (AMPTS-II). Pre-treatments led to enhanced COD solubilisation as compared to raw sample. Alkaline aided enzymatic pre-treatment led to the highest sugar yield, comparable to the theoretical yield. However, high sugar yield did not translate to high methane yield. The best pre-treatment in terms of methane yield was alkaline pre-treatment which resulted in a surplus of up to 88\% methane yield. There was a positive correlation between dissolved COD and methane yield. Methane yield and methane production rate also increased with decreasing particle sizes. In all investigated scenarios, pre-treatment led to an improved methane production rate as compared to the raw samples. These results demonstrated that alkaline pre-treatment at ambient temperature was an efficient treatment option to improve methane yield of bamboo waste. (C) 2013 Elsevier B.V. All rights reserved.
In this paper, we disclose a novel saccharification technology for lignocellulosic biomass. A new carbon based solid (C-SO3H) acid catalyst was first synthesized by a simple, one-step hydrothermal carbonization method using microcrystalline cellulose and sulfuric acid. The functional group, chemical composition and structure of the catalyst were characterized. After five reuses, the solid acid catalyst still showed a high catalytic activity for corncob pretreatment. Under optimal pretreatment conditions (140 degrees C, 6 h, 0.25 g of corncob, 0.25 g of catalyst, and 25 mL of water), xylose was directly released from corncob in a high yield (78.1\%). Enzymatic hydrolysis of the pretreatment residue provided an h. The structure, morphology, and components of the corncob and residues were analyzed. The high xylose and glucose yields confirmed the high catalytic activity of the synthetic carbon-based solid acid, providing green and effective lignocellulose utilization.
Steam explosion of oil palm frond has been carried out under different temperatures between 180 and 210 degrees C for 4 min (severity of 2.96-3.84) after impregnation of the frond chips with water or KOH solution. The effects of impregnation and steam explosion conditions of oil palm fronds on the water soluble fraction and insoluble fraction were investigated. The maximum yield of hemicelluloses in water soluble fractions recovered was 23.49\% and 25.33\% for water and KOH impregnation, treated with steam explosion at temperature of 210 degrees C (severity of 3.84) with a fractionation efficiency of 77.30\% and 83.32\%, respectively. Under this condition, the water insoluble fractions contained celluloses at 60.83\% and 64.80\% for water and KOH impregnation, respectively. The steam explosion temperature of 210 degrees C for 4 min (logR(o) 3.84) was found to be the best condition in the extraction of hemicelluloses from OPF for both types of impregnation. (C) 2014 Elsevier Ltd. All rights reserved.
A novel bio-based polyurethane (BPU) hydroponic foam was developed by substituting up to 100\% of petroleum-derived polyol with bio-polyol derived from cost-effective organosolv fractionation of Miscanthus in an acetic acid-water (9/1, v/v) mixed solvent. The optimal operating conditions for organosolv fractionation were determined to be 100 ? for 120 min with 10\% H2SO4 (based on dry biomass), yielding \~{
Intracellular metabolites were evaluated during the continuous growth of Trichoderma harzianum P49P11 under carbon-limited conditions. Four different conditions in duplicate were investigated (10 and 20 g/L of glucose, 5.26/5.26 g/L of fructose/glucose and 10 g/L of sucrose in the feed). Differences in the values of some specific concentrations of intracellular metabolites were observed at steady-state for the duplicates. The presence of extracellular polysaccharide was confirmed in the supernatant of all conditions based on FT-IR and proton NMR. Fragments of polysaccharides from the cell wall could be released due to the shear stress and since the cells can consume them under carbon-limited conditions, this could create an unpredictable carbon flow rate into the cells. According to the values of the metabolite concentrations, it was considered that the consumption of those fragments was interfering with the analysis. (c) 2020 The Author(s). Published by Elsevier Ltd on behalf of British Mycological Society. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
The study investigated the durability performance of lime and fly ash stabilized lateritic soil blocks subjected to conditions of alternate wetting and drying. A locally available lateritic soil was collected and characterized in the laboratory for its geotechnical properties. The soil was then stabilized using lime and fly ash of various combinations. The blocks were tested for their compressive strength, water absorption and efflorescence. Durability was evaluated by subjecting the blocks to three cycles of wetting and drying and testing its compressive strength. The investigation revealed that fly ash-lime stabilization was capable of producing stabilized blocks meeting the standard requirements of Indian codes in terms of compressive strength, water absorption and efflorescence. The results revealed that a combination of 10 \% fly ash with 10 \% lime was enough to stabilize the soil to achieve the strength of a class 20 block whereas a combination of 10 \% fly ash and 14 \% lime was required to achieve the strength of a class 30 block. Wetting and drying cycles resulted in a marginal increase in strength after the first cycle but reduction thereafter. The optimal combination of 10 \% fly ash and 14 \% lime resulted in less than 25 \% loss in strength after three cycles of wetting and drying.
The objective of this work was to optimize the total cellulase activity of the crude extract cocktails from five white rot fungi produced by solid-state fermentation, by means of the central composite design. The white rot fungi Pleurotus ostreatus PLO 06, Pleurotus eryngii PLE 04, Trametes versicolor TRAM 01, Pycnosporus sanguineus PYC 02 and Phanerochaete chrysosporium PC were tested. For optimization process aiming at the maximum value of total cellulase activity (FPAse), the multi-enzyme cellulase complexes (crude extracts) of each fungus were mixed simultaneously in different proportions. There was increase in FPAse activity for the cocktails formed by the extracts of the five fungi together, compared to the extracts of each fungus alone. The model presented the minimum cocktail of enzymes for maximum total cellulase activity, with 100.00 mu L PYC; 100.00 mu L PC; 100.00 mu L PLO06; 100.00 mu L PLE04 and 200 mu L TRAM01. The maximum value found was of 304.86 U/L. The result of the cocktails was very relevant, showing that there is an enzymatic complementation in the extracts that should be further studied. Concentrated extract cocktails should also be evaluated for biomass saccharification.
In this study, Seed pods of B. ceiba were used as a novel, cheap, and sustainable feedstock for second-generation bioethanol production. B. ceiba waste was pretreated with NaOH under different conditions using a Box-Behnken design (BBD) with three factors and three levels. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) were used to investigate the chemical, structural, and morphological modifications made by pretreatment. NaOH pretreatment followed by steam was more effective as it offered 60\% cellulose and 9\% lignin at 10\% substrate loading, 5\% NaOH conc., and 4 h residence time. Samples with maximum cellulose were employed for ethanol production by separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) using indigenously produced cellulase as well as commercial cellulase. HPLC analysis revealed the best saccharification (50.9\%) at 24 h and the best ethanol yield (54.51 g/L) at 96 h of fermentation in SSF using commercial cellulose by Saccharomyces cerevisiae. SSF offered a better production of bioethanol from seed pods than SHF. The implications of the work support the notion that B. ceiba waste could be utilized for large-scale bioethanol production.
Agricultural wastes especially empty fruit bunch (EFB) are abundantly available to be utilized as a feedstock for biochemical synthesis or biofuel production. The components of the waste include lignin, hemicellulose and cellulose. Cellulose, the polymer of glucose, is the active component for producing bio-based chemicals. However, it is difficult to isolate cellulose since lignin, the most outer layer in the waste is recalcitrant. Therefore, the agricultural wastes need to be pre-treated prior to downstream processing. The aim of this study was to investigate the effect of ozone pretreatment on lignin degradation and total reducing sugar (TRS) yield. EFB was pre-treated using ozone gas in a ribbon-mixer reactor. The chemical and structural changes of ozonated EFB were analysed. The highest delignification obtained were 95.7 wt.\% and TRS yield was enhanced to 84.9\% at a moisture content of 40 wt.\% with 60 g/ m(3) ozone concentration within one hour of reaction time. Both NMR and FTIR spectra conferred major peaks inferring higher lignin degradation could be achieved using ozonolysis. Copyright (C) 2021 by Authors, Published by BCREC Group.
A semi-batch reactor was used to carry out the pyrolysis of Ageratum conyzoides. The outcome of pyrolysis parameters vis temperature (350-600 degrees C); heating rate (25-100 degrees C min(-1)) and sweeping gas (N-2) flow rate (0.1-0.5 L min(-1)) were observed on the product yield. The fixed particle size of 0.425 mm was maintained throughout the pyrolysis process. The maximum pyrolytic-oil yield of 37.55 mass\% was achieved at a temperature of 525 degrees C under a constant heating rate and sweeping gas flow rate of 75 degrees C min(-1) and 0.2 L min(-1). Biomass, biochar, pyrolytic-oil and pyrolysis-gas were characterized through CHNS and O, FT-IR, TG and DTG, SEM-EDX, BET, XRD, H-1-NMR and GC-MS analysers. The A. conyzoides pyrolytic-oil and biochar has an empirical formula of CH1.32O0.82 and CH0.82O0.44 and a high heating value of 17.79 MJ kg(-1) and 22.93 MJ kg(-1). Presence of lower and higher hydrocarbon compounds in pyrolytic-oil makes it a suitable feedstock for the production of various chemicals. High alkalinity and carbonaceous nature of biochar make it suitable for the modification of soil or can be utilized as a solid fuel. The pyrolysis-gas has a gross calorific value of 5.32 MJ m(-3) and can be utilized as an alternative gaseous energy source.
BACKGROUNDPistachio shell is a valuable lignocellulosic biomass because almost 90\% of its hemicellulose fraction is xylan, which can be converted into high value-added compounds such as xylooligosaccarides, xylose, xylitol and furfural. The present study represents a green and novel approach to produce xylose from lignocellulosic biomass. Microwave-assisted high-pressure CO2/H2O hydrolysis (MW-HPCO2) comprising a combination never previously used was performed to produce xylose from pistachio shell. RESULTSResponse surface methodology with a Box-Behnken design was implemented to optimize microwave-assisted high-pressure CO2/H2O hydrolysis (MW-HPCO2). The effect of temperature, time and liquid-to-solid ratio was studied in the ranges of 180-210 \& DEG;C, 10-30 min and 5-30 mL g(-1), respectively. A maximum xylose yield of 61.39\% and minimum degradation compounds (5-hydroxymethyl furfural and furfural) of 11.07\% were attained under reaction conditions of 190 \& DEG;C, 30 min and 18 mL g(-1). CONCLUSIONThe results showed that hydrolysis temperature, time and liquid-to-solid ratio had a strong influence on the xylose yield, as well as on the formation of degradation compounds. MW-HPCO2 significantly increased accessibility to cellulose-derived products in the subsequent enzymatic hydrolysis. The results of the present study reveal that MW-HPCO2 can be a promising green technique for the hydrolysis of lignocellulosic biomass. \& COPY; 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley \& Sons Ltd on behalf of Society of Chemical Industry.
Processes that can convert lignocellulosic biomass into biofuels and chemicals are particularly attractive considering renewability and minimal environmental impact. Ionic liquids (ILs) have been used as novel solvents in the process development in that they can effectively deconstruct recalcitrant lignocellulosic biomass for high sugar yield and lignin recovery. From cellulose-dissolving ILs to choline-based and protic acidic ILs, extensive research in this field has been done, driven by the promising future of IL pretreatment. Meanwhile, shortcomings and technological hurdles are ascertained during research and developments. It is necessary to present a general overview of recent developments and challenges in this field. In this review paper, three aspects of advances in IL pretreatment are critically analyzed: biocompatible ILs, protic acidic ILs and combinatory pretreatments.
A decline in the availability of fossil fuel resources coupled with deleterious environmental concerns has prompted further research into biofuels. Conventional bioethanol production via a first-generation approach may soon become superseded through integration with lignocellulosic feedstocks. However, the underlying concerns pertaining to the disposal of high-strength liquid waste (i.e. spentwash) remain both unchanged and constitute a substantial cost to bioethanol manufacturers. Therefore this review details current efforts in the literature to elucidate various approaches for spentwash treatment and investigate the potential for resource recovery. Insight into the composition of distillery wastewater is given in the lead-up to a thorough discussion encompassing the origin, transformation and characterisation of the highly problematic melanoidin compounds entrained within this effluent. Close examination of advanced organic characterisation methods used by researches yields further insight into the nature of spentwash dissolved organic matter (DOM). Employment of both biological and physio-chemical treatment schemes to alleviate the environmental footprint of such high-strength wastewater are also reviewed. Opportunities to dramatically improve the economic viability of biofuel production by exploiting the potential for resource recovery in the form of energy, organic/inorganic constituents and effluent reuse are discussed. Overall, the review culminates by highlighting recommendations for future work to accelerate the onset of an environmentally benign bio-refinery. (C) 2019 Elsevier Ltd. All rights reserved.
Mannitol is a polyol commonly used in food and pharmaceutical industries. Its biological large-scale production is hindered by the elevated costs of fructose-rich feedstocks. Grape must could be an interesting substrate for this process, due to its bulk production and to the commercial imbalance caused by unsold wine stocks. In the present work, red must and white must were assessed as feedstocks for mannitol production employing three Lactobacillales species. It was experimentally determined that nutrient supplementation could be limited to manganese and yeast extract, and that grape must should be diluted with water to improve mannitol production. Under optimal conditions, Lactobacillus intermedius NRRL B-3693 produced 68.9 g/L mannitol from red must and 79.8 g/L mannitol from white must in 48 h, attaining yields of 0.888 and 0.895 mol/mol, respectively. In order to further reduce costs, yeast extract was replaced by wine lees, resulting in mannitol concentrations of 59.4 g/L for red must and 65.6 g/L for white must in 144 h by using red wine lees and L. intermedius NRRL B-3693. Therefore, winery surplus and by-products could be used to produce mannitol, thus opening new biorefinery opportunities.
During liquid hot water (LHW) pretreatment, lignin is mostly retained in the pretreated biomass, and the changes in the chemical and structural characteristics of lignin should probably refer to re-/depolymerization, solubilization, or glass transition. The residual lignin could influence the effective enzymatic hydrolysis of cellulose. The pure lignin was used to evaluate the effect of LHW process on its structural and chemical features. The surface morphology of LHW-treated lignin observed with the scanning electron microscopy (SEM) was more porous and irregular than that of untreated lignin. Compared to the untreated lignin, the surface area, total pore volume, and average pore size of LHW-treated lignin tested with the Brunner-Emmet-Teller (BET) measurement were increased. FTIR analysis showed that the chemical structure of lignin was broken down in the LHW process. Additionally, the impact of untreated and treated lignin on the enzymatic hydrolysis of cellulose was also explored. The LHW-treated lignin had little impact on the cellulase adsorption and enzyme activities and somehow could improve the enzymatic hydrolysis of cellulose.
Biohydrogen is a promising low-carbon energy vector because its high energetic density, and emerging technologies has been studied aiming achieving higher efficiency and competitive H-2 production, as is the case of dark fermentation. The objective of this paper is to review dark fermentative biohydrogen production from lignocellulosic biomass, presenting insights of biomass pretreatment methods, influential factors in dark fermentation, and environmental and economic aspects. Rice, corn, and wheat residues have been the main lignocellulosic sources studied, and biohydrogen production ranged from 12 to 7019 mL H-2/L. This wide variation is due to the source of lignocellulosic and its pretreatment method, the source and treatment conditions of the inoculum, and the operational conditions of dark fermentation. Acid hydrolysis has been the most applied method to breakdown the complex structure of lignocellulosic biomass, and enzymatic hydrolysis has been used in sequence to improve the process. Moreover, additives (mainly metal materials) have been studied to enhance dark fermentation and lignocellulosic biomass pretreatment. Heat-treated mixed culture is the main used source of inoculum -100 degrees C for 30 min is the most usual condition. Temperature, pH, and hydraulic retention time (HRT) have also high influence in the biohydrogen production and yield. Mesophilic temperatures (around 37 degrees C), pH near 7.0, and HRT of 72 h, are recurrent parameters of dark biohydrogen fermentation. Finally, most studies focused on laboratory scale, which suggest advanced studies on a large scale, and alternatives to improve lignocellulosic biomass pretreatment and biohydrogen production is necessary to make this technology efficient, economical and sustainable.
Bio-oil contains organics with the potential application as liquid fuels for use in vehicles via upgrading. Nevertheless, the applications of bio-oil depend on its properties, which are further indicated by the origin of the biomass feedstock, pyrolysis conditions and configuration of pyrolysers. It of importance of establishing the correlation between the properties of biomass and features of corresponding bio-oil formed, the bio-oils obtained from 20 types of biomasses ranging from different woods, agriculture wastes including various grass types and other biomasses including coconut shell, etc were studied. The features of bio-oils were compared and correlated with the features of the biomasses. The results indicated that the relative proportions of the subcomponents of biomass had significant impacts on the distribution of the species produced. For woody biomass, cellulose and hemicellulose could have more contribution to the formation of the gas. Effects of the subcomponents in biomass on the formation of bio-oil and biochar were very complicated, and it was difficult to establish direct correlation between lignin content and char yield. Nevertheless, the inorganic species in biomass catalyzed charring reactions, leading to the biochar formation increase while the decreased production of bio-oil. Other factors such as mass transfer limitations, heat transfer and especially biological structures of biomass also influenced the products. Comparing with woody biomass, higher yields of gaseous products and biochar with correspondingly lower bio-oil yields was produced from the herbaceous biomass, relating to the high ash content and the distinct biological structure of herbaceous biomass.
Grass clipping, a cellulose-rich raw material, has great potential to produce biofuels, but must be firstly hydrolyzed to liberate fermentable sugars. In this study, grass clipping was pretreated with ultrasound (US), Ca (OH)(2), NaOH, US-Ca(OH)(2) and US-NaOH at relatively low temperature to enhance its enzymatic hydrolysis. The solubilization of hemicellulose and lignin, and crystallinity index of cellulose increased after US-alkaline pretreatment, leading to a significant increase of enzyme accessibility to cellulose. Compared with another four pretreatments, US-Ca(OH)(2) pretreatment of grass clipping showed the best improvement for reducing sugar yield. X-ray diffraction (XRD) determination and scanning electron microscope (SEM) observation showed that the crystallinity index of grass clipping increased and the grass clipping surface suffered from serious erosion after US-Ca(OH)(2) pretreatment. Then, the operating conditions of US-Ca(OH)(2) pretreatment and enzymatic hydrolysis were systematically optimized, and the suitable operating conditions were as follows: US power density of 0.65 W/ml, US pretreatment time of 30 min, Ca(OH)(2) concentration of 0.75\%, pretreatment temperature of 75 degrees C, enzyme loading of 125 FPU/g, and hydrolysis time of 72 h. The reducing sugar yield of grass clipping pretreated by US-Ca(OH)(2) reached 414 mg/g, increasing by 3.5 times compared with that of raw grass clipping. The US-Ca(OH)(2) pretreatment of grass clipping at low temperature significantly enhanced the potential of grass clipping as a promising raw material to produce biofuels.
Ozonolysis, as a lignocellulosic biomass pretreatment, goes back to 80s; however, in the last years it is becoming widespread again owing to its efficiency and mild operation conditions. Ozone reacts preferably with lignin than carbohydrates, promoting biomass destructuration and delignification, and so the sugar release by enzymatic hydrolysis. The hydrolysate from pretreated biomass has being used as sugars source for second-generation fuels production, mainly ethanol, methane and hydrogen. Short-chain carboxylic acids are the main inhibitory compounds generated, being properly removed by water washing. The most common inhibitory compounds reported for other pretreatments, furfural and HMF (5-hydroxymethylfurfural), are not found in ozone-pretreated hydrolysates. Composition of pretreated biomass and ozone consumption depends on several process parameters: reactor design, moisture content, particle size, pH, reaction time, ozone/air flow and ozone concentration. Additional studies are necessary to clarify process parameters effect and to optimize the process to achieve high yields with economic feasibility. (C) 2015 Elsevier Ltd. All rights reserved.
Cationic polymers (cationic polyacrylamide (CPAM), polyethyleneimine (PEI) or cationic starch (CS)) were used to enhance the enzymatic hydrolysis of waste paper fibers (WPFs) at 15\% (w/w) solids concentration. Results showed that 0.05 g/L PEI, CPAM and CS resulted in 72.5\%, 65.9\% and 59.7\% conversion of WPFs, increased by 15.4\%, 8.8\% and 2.6\%, respectively, compared with control (57.1\%). PEI was shown to have a larger effect than CPAM and CS, and generate a total sugar concentration of 73.9 g/L. Improvement in hydrolysis with cationic polymer addition is attributed to increased cellulase adsorption on cellulose through electrostatic attraction, rather than enhancement of cellulase activity. A patching/bridging mechanism of cationic polymer enhancement of cellulose adsorption in cellulose is hypothesized. PEI exhibited maximum cellulose binding for polymers examined and appears to promote binding through a patching mechanism. CPAM and CS adsorbed a relatively low cellulase through bridging mechanism. In addition, enzyme loading could be reduced by addition of cationic polymers to obtain the same glucose yield, especially when PEI was used.
In this study, pretreatment of corn stalks with the cellulosic fungus Aspergillusfumigatus CLL was performed to enhance its saccharification. The effect of feedstock loading (10 g/L and 20 g/L) on corn stalk pretreatment performance and the effects of Trichodermareesei cellulase and commercial cellulase on the saccharification of pretreated corn stalks were investigated. The results indicated that with a solid loading of 10 g/L for 2 days at 30 degrees C, 25.2\% lignin was degraded, whereas the degradation was only 2.8\% under solid loading of 20 g/L. Pretreated corn stalks (solid loading 10 g/L for 2 days at 30 degrees C) saccharified by 300 U/L T.reesei cellulose exhibited 3.4 times higher sugar yields (67.9\%) compared to the raw feedstocks, and the value was comparable with the saccharification performance of commercial cellulase (60.8\%). These results demonstrated that A.fumigatus CLL not only decomposed the structure of corn stalks but also complemented the incomplete cellulase system of T.reesei. A.fumigatus CLL can be used to pretreat lignocellulosic materials to enhance the saccharification performance.
Artemisia ordosica, a promising biofuel production material, was pretreated by alkali (Ca(OH)(2)) soaking-electron beam irradiation (EBI) to improve enzymatic digestibility. After 72 h enzymatic hydrolysis, alkali soaking-EBI pretreated sample showed high reducing sugar yield. The content of lignin and hemicellulose in Artemisia ordosica decreased after alkali soaking-EBI pretreatment. SEM observation showed that the Artemisia ordosica surface with alkali soaking-EBI pretreatment suffered serious erosion. The conditions of alkali soaking-EBI pretreatment and enzymatic hydrolysis were optimized. Under the optimal conditions, the reducing sugar yield of Artemisia ordosica achieved 520.67 mg/g, which increased by 1136.75\% comparing to the untreated control group. The Artemisia ordosica with alkali (Ca(OH)(2)) soaking-EBI pretreatment is a promising potential for biofuel production.
Background Xylitol has a wide range of applications in the pharmaceuticals, cosmetic, food and beverage industry. Microbial xylitol production reduces the risk of contamination and is considered as environment friendly and sustainable compared to the chemical method. In this study, random mutagenesis and genetic engineering approaches were employed to develop Candida tropicalis strains with reduced xylitol dehydrogenase (XDH) activity to eliminate co-substrate requirement for corn cob-based xylitol-ethanol biorefinery.Results The results suggest that when pure xylose (10\% w/v) was fermented in bioreactor, the Ethyl methane sulfonate (EMS) mutated strain (C. tropicalis K2M) showed 9.2\% and XYL2 heterozygous (XYL2/xyl2 Delta::FRT) strain (C. tropicalis K21D) showed 16\% improvement in xylitol production compared to parental strain (C. tropicalis K2). Furthermore, 1.5-fold improvement (88.62 g/L to 132 g/L) in xylitol production was achieved by C. tropicalis K21D after Response Surface Methodology (RSM) and one factor at a time (OFAT) applied for media component optimization. Finally, corncob hydrolysate was tested for xylitol production in biorefinery mode, which leads to the production of 32.6 g/L xylitol from hemicellulosic fraction, 32.0 g/L ethanol from cellulosic fraction and 13.0 g/L animal feed.Conclusions This work, for the first time, illustrates the potential of C. tropicalis K21D as a microbial cell factory for efficient production of xylitol and ethanol via an integrated biorefinery framework by utilising lignocellulosic biomass with minimum waste generation.
A new biomass pretreatment method is mandatory to solve the existing issues, such as energy-intensive and expensive methods and the challenges of scaling up the biomass conversion processes. In this study, we pretreated the corncob biomass using the combined lime and hydrodynamic cavitation process and optimized the process conditions using the response surface methodology. The combined pretreatment process parameters in the hydrodynamic cavitation reactor included lime loading (0.05-0.15 g g(-1)), biomass loading (2.5-5\%), and time (5-60 min). After optimization, maximum lignin reduction by 38.1\% and cellulose increase by 22.6\% were achieved at 0.1 g g(-1) lime loading and 5\% biomass loading after 60 min of pretreatment. Thus, the combined hydrodynamic cavitation reactor (HCR) and lime pretreatment is an efficient method for pretreatment of lignocellulosic biomass.
In the present study, a suspension of nanofibrillated cellulose from eucalyptus was spray-dried in order to obtain a powdered material that could be easily transported and stored. The original suspension and the dried material were characterized for their physical, morphological and thermal properties. An increase in crystallinity and reduction in thermal stability were observed after drying. In addition, the fibrils size passed from nano to micro scale The powder obtained was rehydrated and homogenized by two methods: rotor-stator homogenization (5000, 10,000 and 15,000 rpm) and ultrasound (10, 30 and 50\% maximum amplitude), during 3 and 5 min, in order to verify the possibility of obtaining a stable reconstituted suspension comparable to the original one. Higher treatment intensities resulted in suspensions with higher viscosity and stability. The suspension homogenized by ultrasound at 50\% amplitude for 5 minutes was the most stable one and restored the nano dimensions of the original suspension. Both the original and the reconstituted suspensions showed a shear thinning and ``gel-like{''
Cellulose nanocrystals (CNCs) have novel and diversified applications in different fields including packaging and nanodelivery systems. This study was dedicated to fabricate CNCs from walnut shell as an abundant source of agricultural byproducts using alkali/acidic hydrolysis method. Moreover, homogenizer and ultrasound devices were applied to produce the CNCs with minimum hazardous solvents in the preparation steps. The physicochemical characteristics of CNCs, such as color, size, yield, and swelling capacity plus their characterization using X-ray diffraction (XRD), thermogravimetric analysis (TGA) and Fourier-transform infrared spectroscopy (FTIR) were studied. The mean equivalent spherical diameter of the fabricated CNCs was about 130 nm and the production efficiency was 91.5\%. Besides, the swelling capacity of CNCs was 1.5-fold of cellulose with a swelling of 400\%. The crystallinity degree of the cellulose obtained from walnut shell was 49\%, which was improved following acidic and alkali hydrolysis (60\%). TGA analysis revealed that the thermal stability of the CNCs was lower than cellulose; moreover, the FTIR results demonstrated that there is not a considerable difference between normal cellulose and CNCs. Overall, it was concluded that walnut shell-derived CNCs have the potential to be employed as promising nanocarriers in different sectors, especially in the food and drug delivery sectors. (C) 2018 Elsevier B.V. All rights reserved.
This communication discusses the optimization of key factors for the enhanced bio-hydrogen production from water hyacinth. Three critical factors inoculums age (18-24 h), inoculums volume (20-80 ml/l) and concentration of sulphuric acid (0.5-2.0\%) were optimized by response surface methodology (RSM) with central composite design (CCD) for better production. RSM analysis showed that all three factors significantly influenced hydrogen production. The optimum hydrogen production was 705 ml/l obtained with 21 h old bacterial culture, 50 ml/l inoculums with 1.25\% sulphuric acid pre-treatment. The hydrogen concentration produced by Clostridium acetobutylicum NCIM 2877 was enhanced after using RSM. The results obtained indicate that RSM with CCD can be used as a technique to optimize culture conditions for enhancement of hydrogen production by pre-treatment of low-cost organic substrate; water hyacinth using dark fermentation methods may be one of the most promising approaches.
As a result of environmental concerns and the depletion of biomass assets, eco-friendly, renewable biomass-based chemical extraction has recently received significant attention. Bio-based chemicals can be prepared using different renewable feedstock bio-resources through microbial fermentation. Chemicals produced from renewable feedstocks can reduce ecological consequences from improper disposal and repurpose them into valuable products. Biodegradability, biocompatibility and non-toxicity, particularly in biomedical applications, have inspired researchers towards developing novel technologies that have social benefit. Among semi-synthetic and synthetic polymeric materials, utilization of natural bio-based monomeric materials can provide opportunities for sustainable development of novel non-toxic, biodegradable and biocompatible products. The purpose of this work is to give a summary of research into the generation of natural bio-based succinic acid (SA) monomer, the development of poly(butylene succinate) (PBS) as biodegradable polymer, PBS-based nanocomposites and their innovative uses.
Two-stage acid/alkali pretreatment was used to enhance the saccharification efficiency of sweet sorghum fiber. The physicochemical characterizations of the pretreated fibers were evaluated by SEM, FTIR and XRD. The acid and alkali sequence in the two-stage pretreatment process was compared, and their dosage was optimized. The results indicated that the two-stage pretreatment showed better saccharification performance when compared with conventional single stage pretreatment. And compared with the acidalkali sequence, the alkali-acid sequence achieved higher glucose yield (0.23 g g(-1)) under the optimized conditions, which was 1.64 and 1.21 times higher than that of the single stage and the acid-alkali pretreatments, respectively. Overall, the two-stage pretreatment process is a promising approach to achieve high fermentable glucose conversion rate of cellulosic material. (C) 2016 Elsevier Ltd. All rights reserved.
Utilisation of biomass as fuel is very attractive from the ecological point of view. Such way of energy extraction is ecologically clean (zero CO2 emission) and biomass is renewable and theoretically inexhaustible local energy source. However, during the utilisation of secondary raw materials of biomass for energy production, higher amount of ash accumulates. Wood ash analysed in the research consists of two types of particles: first type - nonflammable mineral particles consisting of the following main elements: Si, Ca, Fe, O and C (86\%) and the main elements of the particles of second type are C and 0 (98\%). The aim of the research is to analyse the possibility to utilise wood ash from biomass for the production of ceramic products. Formation masses are prepared by incorporating from 5\% to 60\% of wood ash additive and burned at various temperatures. It is identified that this additive influences the properties of ceramic body, i.e. reduces drying and burning shrinkage, density, compressive strength, thermal conductivity, increases water absorption and porosity. Additive of wood ash from biomass influences the ceramic body as a natural pigment that brightens the ceramic body. Colour change is determined by sufficient amounts of calcium pyroxene in the composition thereof iron is inserted. (C) 2016 Elsevier Ltd. All rights reserved.
Bioethanol is the most commonly used renewable biofuel as an alternative to fossil fuels. Many microbial strains can convert lignocellulosics into bioethanol. However, very few natural strains with a high capability of fermenting pentose sugars and simultaneously utilizing various sugars have been reported. In this study, fermentation of sugar by Fusarium oxysporum G was performed for the production of ethanol to improve the performance of the fermentation process. The influences of pH, substrate concentration, temperature, and rotation speed on ethanol fermentation are investigated. The three significant factors (pH, substrate concentration, and temperature) are further optimized by quadratic orthogonal rotation regression combination design and response surface methodology (RSM). The optimum conditions are pH 4, 40 g/L of xylose, 32 degrees C, and 110 rpm obtained through single factor experiment design. Finally, it is found that the maximum ethanol production (10.0 g/L) can be achieved after 7 d of fermentation under conditions of pH 3.87, 45.2 g/L of xylose, and 30.4 degrees C. Glucose is utilized preferentially for the glucose-xylose mixture during the initial fermentation stage, but glucose and xylose are synchronously consumed without preference in the second period. These findings are significant for the potential industrial application of this strain for bioethanol production.
This work describes the feasibility of using almond shell as feedstock for bioethanol production. A pretreatment step was carried out using 4\% NaOH for 60 min at 121 degrees C followed by 1\% sulfuric acid for 60 min at 121 degrees C. Enzymatic saccharification of the pre-treated almond shell was performed using Penicillium occitanis enzymes. The process was optimized using a hybrid design with four parameters including the incubation time, temperature, enzyme loads, and polyethylene glycol (PEG) concentration. The optimum hydrolysis conditions led to a sugar yield of 13.5\%. A detoxification step of the enzymatic hydrolysate was carried out at pH 5 using 1 U/ml of laccase enzyme produced by Polyporus ciliatus. Fermenting efficiency of the hydrolysates was greatly improved by laccase treatment, increasing the ethanol yield from 30\% to 84\%. These results demonstrated the efficiency of using almond shell as a promising source for bioethanol production. (C) 2016 Elsevier Ltd. All rights reserved.
Ionic liquid (IL) based pretreatment of lignocellulosic biomass for facilitating efficient enzymatic saccharification has emerged as an environmentally benign approach that offers several advantages over conventional strategies. However, residues of ionic liquid left in the pretreated biomass may cause inactivation of saccharifying enzymes thus, necessitating the requirement of ionic liquid-stable enzymes. Cost-effective production of industrial enzymes is always desired to enhance the overall process economy. Current study reports IL-stable cellulase production from a newly isolated bacterium Bacillus subtilis G(2). Design of experiment (DoE) based on response surface methodology was used in sequential manner for optimizing cultural and environmental variables to enhance cellulase production by 2.66-fold. IL-stable cellulase was used for saccharification of IL-pretreated pine needle biomass (PNB) with 1-ethyl-3-methylimidazolium methanesulfonate in a consolidated single pot process i.e. one pot consolidated bioprocess (OPCB). The saccharification efficiency of 23.57 \% was observed under OPCB. The hydrolsate obtained was fermented by dual culture of yeast i.e. Saccharomyces cereviasie NCIM 3078 and Pichia stipitis NCIM 3497, and a yield of 0.092 g ethanol/g of PNB was obtained with fermentation efficiency of 25.62 \%. This study is first ever where-in IL-stable cellulase production is accomplished using agroindustrial residues by employing DoE, and assessed for its application potential under OPCB for saccharification of IL-pretreated PNB. IL-stable cellulases would not only preclude expensive washing step following IL-pretreatment of biomass, but their application in a consolidated single pot process (OPCB) offers numerous technoeconomic advantages over conventional multi pot processes.
This study investigated potential synergistic activities between tar sand and walnut shell during co-pyrolysis. A series of pyrolysis studies were conducted under specific operating conditions in a fixed-bed reactor. The highest yield of bio-oil from the co-pyrolysis was 31.84 wt.\%, which represented an increase of 7.88 wt.\% compared to the bio-oil yield from the pyrolysis of walnut shell alone. The bio-oils were characterized using various spectroscopic and chromatographic analysis techniques. The results indicated that the synergetic effect increased the co-pyrolysis bio-oil yield and its quality. Consequently, the results indicate that the bio-oils obtained will be suitable for the production of fuels and chemicals as feedstock after required improvements. (C) 2011 Elsevier Ltd. All rights reserved.
Paper mulberry, a fast-growing and vigorous plant, is a potential substrate for producing lignocellulosic bioethanol and an important renewable alternative to fossil fuels. In order to improve the economic feasibility of ethanol production from paper mulberry, H3PO4/H2O2 pretreatment was selected as the most suitable pretreatment method that could produce the highest glucose concentration (131 g/L) compared with other pretreatments (73.2-89.3 g/L) at high solid loading. Whereafter, the final solid loading of H3PO4/H2O2 pretreatment was significantly increased to 40\% (w/v) without any decrease in the final glucose concentration. Finally, a novel Fed-nonisothermal-simultaneous saccharification and fermentation was constructed using H3PO4/H2O2 pretreated paper mulberry, which bypassed the inhibition caused by paper mulberry solid and high temperature on the traditional simultaneous saccharification and fermentation, improving ethanol concentration (63.9 g/L), ethanol productivity (1.33 g/L/h) and ethanol yield (0.160 g/g-biomass) by 30.4\%, 30.4\% and 30.1\%, respectively, compared to those obtained from SSF (simultaneous saccharification and fermentation) process. Thus, we have opened up a novel way to produce ethanol or other biofuels using the paper mulberry as an outstanding alternative substrate. (C) 2020 Elsevier Ltd. All rights reserved.
The purpose of this study is to target well-defined xylooligosaccharides by controlled sulfuric acidic hydrolysis of beechwood xylans. Parameters such as sulfuric acid and xylan concentrations, hydrolysis duration and temperature have been investigated, allowing optimum conditions to be determined (0.7 M H2SO4, 90 degrees C, 45 min). The obtained xylooligosaccharides show a well-defined structure and have been characterized using several techniques such as 1D and 2D nuclear magnetic resonance spectrometry and matrix-assisted laser desorption/ionization-time of flight mass spectrometry. This work demonstrated that mild acidic hydrolysis conditions enable the reproducible production of xylooligosaccharides containing, on average, six xylose units and only one 4-O-methyl-D-glucuronic acid unit likely positioned at the non-reductive chain-end. (C) 2015 Elsevier Ltd. All rights reserved.
This study evaluated the biotechnological production of xylitol from sorghum forage biomass. The yeast Candida guilliermondii was cultivated in hemicellulosic hydrolysates obtained from biomass of three sorghum varieties (A, B, and C). First, the biomass was chemically characterized and subjected to dilute acid hydrolysis to obtain the hemicellulosic hydrolysates which were vacuum-concentrated and detoxified with activated charcoal. The hemicellulosic hydrolysates (initial pH 5.5) were supplemented with nutrients, and fermentations were conducted in 125-mL Erlenmeyer flasks containing 50 mL medium, under 200 rpm, at 30 A degrees C for 96 h. Fermentations were evaluated by determining the parameters xylitol yield (Y (P/S) ) and productivity (Q(P)), as well as the activities of the enzymes xylose reductase (XR) and xylitol dehydrogenase (XDH). There was no significant difference among the three varieties with respect to the contents of cellulose, hemicellulose, and lignin, although differences were found in the hydrolysate fermentability. Maximum xylitol yield and productivity values for variety A were 0.35 g/g and 0.16 g/L.h(-1), respectively. It was coincident with XR (0.25 U/mg prot) and XDH (0.17 U/mg prot) maximum activities. Lower values were obtained for varieties B and C, which were 0.25 and 0.17 g/g for yield and 0.12 and 0.063 g/L.h(-1) for productivity.
This work studies the influence of the alkali pre-treatment of Sorghum Moench - a representative of energy crops used in biogas production. Solutions containing various concentrations of sodium hydroxide were used to achieve the highest degradation of lignocellulosic structures. The results obtained after chemical pre-treatment indicate that the use of NaOH leads to the removal of almost all lignin (over 99 \% in the case of 5 mass \% NaOH) from the biomass, which is a prerequisite for efficient anaerobic digestion. Several parameters, such as chemical oxygen demand, total organic carbon, total phenolic content, volatile fatty acids, and general nitrogen were determined in the hydrolysates thus obtained in order to define the most favourable conditions. The best results were obtained for the Sorghum treated with 5 mass \% NaOH at 121A degrees C for 30 min The hydrolysate thus achieved consisted of high total phenolic compounds concentration (ca. 4.7 g L-1) and chemical oxygen demand value (ca. 45 g L-1). Although single alkali hydrolysis causes total degradation of glucose, a combined chemical and enzymatic pre-treatment of Sorghum leads to the release of large amounts of this monosaccharide into the supernatant. This indicates that alkali pre-treatment does not lead to complete cellulose destruction. The high degradation of lignin structure in the first step of the pre-treatment rendered the remainder of the biomass available for enzymatic action. A comparison of the efficiency of biogas production from untreated Sorghum and Sorghum treated with the use of NaOH and enzymes shows that chemical hydrolysis improves the anaerobic digestion effectiveness and the combined pre-treatment could have great potential for methane generation. (C) 2012 Institute of Chemistry, Slovak Academy of Sciences
This study examined the suitability of husk waste for bioethanol production and compared pretreatment techniques with regard to their efficiencies. Results showed that 4\% NaBH4 (90 mm) delignified the highest amount of lignin (49.1\%) from the structure. The highest xylan solubility (77.9\%) was observed when samples were treated with 4\% NaOH for 90 min. Pretreatment with NaOH and NaBH4, compared to H2O2 and H2SO4, resulted in selective delignification. The highest glucan to glucose conversion (74.4\%) and the highest ethanol yield (52.6 g/kg husks) were observed for samples treated with 2\% NaOH for 90 min. (C) 2012 Elsevier Ltd. All rights reserved.
Hydrothermal pretreatment is an efficient approach to enhance methane production from microalgae biomass by anaerobic digestion. However, the high energy consumption hinders the development of hydrothermal pretreatment. In this study, a solar-driven hydrothermal pretreatment system was proposed to save energy in hydrothermal pretreatment. In this system, microalgae slurry directly flows through the parabolic trough collector and is hydrolyzed while absorbing solar energy. The effects of operation parameters (i.e., direct normal irradiation, flow rate, mass fraction, and retention time) on the yield of organic matter were also investigated. The maximum yield of carbohydrates (267.3 mg/g total solid) and proteins (265.2 mg/g total solid) from pretreated microalgae biomass was 7.4 and 3.7 times that obtained from the raw microalgae slurry, respectively. In addition, the methane produced from the microalgae biomass pretreated by the solar-driven hydrothermal pretreatment system increased by 57\% in anaerobic digestion, compared to that obtained using raw microalgae biomass as a substrate. The solar-driven hydrothermal pretreatment system can be used as an alternative energy saving approach for the hydrothermal pretreatment of microalgae slurry.
In this paper, hemicelluloses from bamboo (Phyllostachys pubescens Mazel) stem aged six months were sequentially extracted with hot water, 2\% KOH, and 5\% NaOH. The water-soluble hemicelluloses HI, and four alkali-soluble hemicellulosic fractions H-2, H-3, H-4 and H-5 were obtained, achieving a total yield of 59.60\% based on the original hemicelluloses. Sugar composition analysis showed that the hemicelluloses were mainly composed of xylose (44.39-72.71\%), arabinose (26.36-51.87\%), ribose (0.93-2.72\%), and uronic acid (0.29-5.27\%). The structures of the hemicelluloses were determined to be mainly arabinoxylan, using the FT-IR and NMR techniques. The AFM images of fraction H-3 revealed a distribution of spherical nanoparticles with different sizes, while the fraction H-2 had helix rod and random coil feature. The SEM characterizations indicated that the fraction H-1 displayed spherical particles while the fraction H-3 had mainly flat particles at high magnification. Thermal stability was also analyzed using TG-DTG method and first-order kinetics model. (c) 2011 Elsevier B.V. All rights reserved.
Hydrolysates obtained by autohydrolysis-posthydrolysis of corncobs were detoxified with charcoal, concentrated, supplemented with nutrients, and fermented with Debaryomyces hansenii. After biomass removal, the fermented media contained 0.1137 kg of nonvolatile components (NVC)/kg of liquor, which corresponded mainly to xylitol (0.6249 kg/kg of NVC) but also to minor amounts of inorganic components (measured as ashes), proteins, nonfermented sugars (xylose and arabinose), uronic acids, arabitol, and other nonvolatile components (ONVC). The media were subjected to further processing (sequential stages of adsorption, concentration, ethanol precipitation, concentration, and crystallization) to obtain food-grade xylitol. Adsorption experiments were carried out at various solid-to-liquor ratios. Under selected conditions (1 kg of charcoal/15 kg of liquors), the xylitol content increased to 0.6873 kg/kg of NVC, and almost total decoloration was achieved. The resulting liquor was concentrated by evaporation to increase its NVC content to 0.4032 kg/kg of liquor (corresponding to a xylitol concentration of 0.280 kg/kg of liquor), and ethanol was added to precipitate a part of the NVC (mainly proteins, but also uronic acids, ashes, and other nonvolatile compounds). Refined liquors (containing 0.7303 kg of xylitol/kg of NVC) were concentrated again, and ethanol was added ( to reach 40-60\% volume of the stream) to allow crystallization at -10 or -5 degrees C. Under selected conditions, 43.7\% of xylitol contained in the initial fermentation broth was recovered in well-formed, homogeneous crystals, in which xylitol accounted for 98.9\% of the total oven-dry weight. Material balances are presented for the whole processing scheme considered in this work.
Aqueous microfibrillated cellulose (MFC) suspensions were prepared by extraction of ground mangosteen (Garcinia mangostana L.) rind with hot aqueous sodium hydroxide, bleaching with hydrogen peroxide, and subsequent shearing in a high pressure homogenizer. The cellulose content of the material markedly increased after the alkali and bleaching pre-treatments. The influences of number of passes through the homogenizer on characteristics of the resulting MFC were investigated. Results show that crystallinity index, degree of polymerization, viscoelaticity, and viscosity of the MFC suspensions decreased as the number of homogenization passes increased, indicating that fiber degradation occurred during homogenization. The emulsion stabilizing properties of MFC, on the other hand, were improved when the number of homogenization passes was increased. The oil-in-water emulsions stabilized by MFC (30\% w/w soybean oil, 0.7\% w/w MFC in aqueous phase, emulsion pH range = 6.8-7.2) obtained at the higher number of homogenization passes exhibited smaller oil droplets, stronger three-dimensional network structures, and more stable to creaming than those stabilized by MFC obtained at the lower number of homogenization passes. The creaming stability of the MFC-stabilized emulsions was reduced at low pH or high salt concentration due to electrostatic screening of the negatively charged MFC particles. Thermal treatment had little influence on the creaming stability of these emulsions. These results should improve understanding of the relationships between processing and characteristics of MFC from a novel lignocellulosic material, i.e. mangosteen rind, and lead to a potential application as an emulsion stabilizer. (C) 2013 Elsevier Ltd. All rights reserved.
The ethanol fermentation efficiency of sweet sorghum stem juice (SSJ) under a very high gravity (VHG) condition (250 g/L of sugar) was improved by immobilized Saccharomyces cerevisiae SSJKKU01, using a stirred tank bioreactor (STR) coupled with a column bioreactor (CR). Dried rattan pieces (as carriers for cell immobilization) at 50\% of the working volume of the CR were suitable for use in a batch ethanol fermentation. The average ethanol concentration (P-E) and ethanol productivity (Q(P)) of repeated-batch fermentation in the CR for eight successive cycles were 109.85 g/L and 1.88 g/L.h, respectively. Then an STR coupled with a CR was applied for repeated-batch ethanol fermentation in two systems. System I was an STR (1.8 L working volume), and System II was an STR (1 L) coupled with a CR, referred to as a CR-F (0.8 L). Both systems were connected to a new CR, called CR-I, containing sterile dried rattan pieces at 50\% of its working volume. Active yeast cells were inoculated only into the STR, and the medium circulation rate between bioreactors was 5.2 mL/min. The results showed that at least eight successive cycles could be operated with an average P-E of 108.51 g/L for System I and 109.44 g/L for System II. The average Q(P) and SC values of both systems were also similar, with values of 1.87 to 1.88 g/L.h and 93 to 94\%, respectively. The morphology of the carriers with and without immobilized cells before and after the fermentation was investigated. The obtained results demonstrated that a repeated-batch fermentation by immobilized cells on rattan pieces, using an STR coupled with a CR, was successfully used to produce high levels of ethanol from SSJ under a VHG condition.
In this article, we report on the synthesis of cellulose esters by the reaction of cellulose and some cyclic anhydrides, such as succinic, maleic, and phthalic anhydrides. For this, an esterification method was finalized. Indeed, cellulose extracted from Posidonia biomass was first solubilized in the solvent system lithium chloride (LiCl)/N,N-dimethylacetamide and then esterified by cyclic anhydride in the presence of catalysts such as N,N-dimethyl-4-aminopyridine, tripropylamine, tributylamine, and calcium carbonate. This method was fast and reproducible with the LiCl system as a solvent and with an efficient activation by controlled microwave power. In this way, the reaction time was reduced from several hours to just a few minutes. The reaction products were characterized by IR and solid-state cross-polarization/magic angle spinning C-13-NMR spectroscopy. The degree of substitution (DS) and the grafted ester group content of the different products were obtained by alkali saponification followed by titration of the excess alkali. Two activation methods were compared, and the results show that the application of classical heating gave less successful results than those obtained by microwave activation. Indeed, with microwave activation, a higher DS (2.25) was obtained after 10 min. However, with classical heating, a value of DS equal to 1.2 was obtained after 12 h. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 119: 3372-3381, 2011
The use of natural rather than artificial materials is of considerable interest in sustainable geotechnics. This review study focused on soil reinforcement with plant fibers and explored the behavior and performance of plant fiber-reinforced soil by random distribution as an effective method for soil improvement. The behavior of fiber-soil composites is essentially governed by the mechanical characteristics of synthetic fibers, but plant fibers have intrinsically distinct properties from synthetic ones. Biochemical and mechanical features of natural fibers determine the behavior of soil-fiber composites. Still, the biochemical and physical properties of fibers have received minimal consideration in geotechnical research involving natural georeinforcement materials. Thus, a thorough examination of the use of natural fibers for soil reinforcement was conducted in this study, and the impacts of the qualities of plant fibers on their performance in the soil were examined. The mechanical behavior of fiber-reinforced soil was then investigated by analyzing laboratory, numerical, and case studies. The behavior of fibers in cohesive and granular soils was subsequently explored. The results demonstrated the significant effect of mechanical characteristics such as Young's modulus and tensile strength, as well as biochemical constituents (cellulose, lignin, and hemicellulose) on the performance and interaction of fibers in the soil. The findings also revealed that plant fibers greatly enhance mechanical parameters such as shear, compressive, and tensile strength. Recommendations are made for soil reinforcement with plant fibers and the selection of appropriate types and amounts of fibers.
Olive tree biomass (OTB) can be used for producing second generation bioethanol. In this work, extracted OTB was subjected to fractionation using a sequential acid/alkaline oxidative pretreatment. In the first acid stage, the effects of sulfuric acid concentration and reaction times at 130 degrees C were investigated. Up to 71\% solubilization of hemicellulosic sugars was achieved under optimized conditions (2.4\% H2SO4, 84 min). In the second stage, the influence of hydrogen peroxide concentration and process time were evaluated at 80 degrees C. Approximately 80\% delignification was achieved under the best operational conditions (7\% H2O2, 90 min) within the experimental range studied. This pretreatment produced a substrate with 72\% cellulose that was highly accessible to enzymatic attack, yielding 82 g glucose/100 g glucose in delignified OTB. Ethanol production from both hemicellulosic sugars solubilized in the acid pretreatment and glucose from enzymatic hydrolysis of delignified OTB yielded 15 g ethanol/100 g OTB. (C) 2017 Elsevier Ltd. All rights reserved.
Co-culturing microorganism to degrade lignocellulose has been adapted by various researchers globally. The decomposition of bamboo-shoot shell powder (BSSP) by a two-fungus (Pleurotus ostreatus and Aspergillus niger) together was examined. During the degradation, there was a rise in the activities of enzymes carboxymethylcellulase (catalyzing cellulose degradation by the hydrolysis of beta-1, 4 glycosidic bonds in cellulosic materials) and laccase (phenol oxidase catalyzing lignin degradation) responsible for metabolism of lignocellulosic material resulting into decrease in acid detergent fiber and lignin contents of BSPP. In addition, the physical properties of the shell fiber were changed from smooth and flexible to rough and crisp. The products of the decomposing fiber were complex, and most of them contained methyl or ethyl groups. The fungi decomposed native silicon compounds simultaneously during biodegradation. The net result of decomposition was a decrease in biomass as well as production of carboxymethylcellulase and laccase, two biotechnologically relevant extracellular enzymes with multiple industrial uses. (C) 2016 Elsevier Ltd. All rights reserved.
Using aquatic biomass as a solid fuel is limited by its low energy density, low lignin content and high moisture content. This study investigated upgrading aquatic biomass as a solid fuel using hydrothermal carbonization with temperatures in the moderate temperatures range for a reaction time of 30 min. Thermogravimetric analysis (TGA) tests were used to study the combustion behavior of the raw aquatic biomass and its derived hydrochar during the combustion process. Chemical composition analysis indicated that compared to the raw aquatic biomass, the fuel quality of the derived hydrochar had been improved by increasing the carbon contents with a substantial decrease in the volatile matter and ash content. Furthermore, higher fuel quality of the derived hydrochar was observed with increasing hydrothermal temperature. Similarly, based on the TGA test, the hydrochars had increased ignition temperatures, higher combustion temperatures and higher burnout temperatures compared to the raw aquatic biomass. The combustion characteristic index values for all hydrochar samples derived from water hyacinth and cattail leaves were appropriate for combustion.
Utilizing the undetoxified wood hydrolysate to accumulate maximum lipids in Rhodosporidium toruloides under optimum conditions has been regarded as a renewable and cost-effective strategy. The current investigation aims to identify the best carbon to nitrogen (C/N 20, 70, and 120) ratio for maximum lipid accumulation in R. toruloides-1588 using wood hydrolysate. Additionally, a fed-batch-like condition was employed, where C/N ratios were maintained during the fermentation that inherently decreases in batch fermentation. The C/N ratio 70 has been identified as the best condition with 3 times higher lipid accumulation (43\% w/w) than the control. Additionally, >95\% and 70\% of glucose and xylose consumption were observed, respectively. Moreover, 50\% increase in polyunsaturated fatty acids compared to the control media reinforced the potential of R. toruloides- 1588 to thrive on undetoxified hydrolysate, high lipid productivity (3.8 mg/g of dry weight per hour) and produce high value monosaturated and polyunsaturated fatty acids.
Organic acid as a class of hydrolysis catalysts shows great potential in the production of xylo-oligosaccharides (XOS) from lignocelluloses. However, sorbic acid (SA) hydrolysis for XOS production from lignocellulose has not been reported and it was still unclear how lignin removal affected XOS production. Herein, two factors affecting the XOS production from switchgrass by SA hydrolysis were explored: hydrolysis severity factor (Log R0) and lignin removal. Benefiting from the lignin removal (58.4\%) in switchgrass, a desired XOS yield of 50.8\% with low by-products was obtained from delignified switchgrass by 3\% SA hydrolysis at Log R0 = 3.84. Under these conditions, 92.1\% of glucose was obtained by cellulase hydrolysis with Tween 80 addition. From a mass balance perspective, 10.3 g of XOS and 23.7 g of glucose could be produced from 100 g switchgrass. This work proposed a novel strategy for XOS and monosaccharides production from delignified switchgrass.
Interest in lignocellulosic biomass conversion technologies has increased recently because of their potential to reduce the dependency on non-renewable feedstocks. Residues from a variety of crops are the major source of lignocellulose, which is being produced in increasingly large quantities worldwide. The commercial exploitation of crop residues as feedstocks for biorefineries which could be used to produce a variety of goods such as biofuels, biochemicals, bioplastics, and enzymes is an attractive approach not only for adding value to residues but also for providing renewable products required by the expanding bioeconomy market. Moreover, the implementation of biorefineries in different regions has the potential to add value to the specific crop residues produced in the region. In this review, several aspects of crop residue application in biorefineries are discussed, including the role of crop residues in the bioeconomy and circular economy concepts, the main technical aspects of crop residue conversion in biorefineries, the main crop residues generated in different regions of the world and their availability, the potential value-added bioproducts that can be extracted or produced from each crop residue, and the major advantages and challenges associated with crop residue utilization in biorefineries. Despite their potential, most biomass refining technologies are not sufficiently advanced or financially viable. Several technical obstacles, especially with regard to crop residue collection, handling, and pre-treatment, prevent the implementation of biorefineries on a commercial scale. Further research is needed to resolve these scale-up-related challenges. Increased governmental incentives and bioeconomic strategies are expected to boost the biorefinery market and the cost competitiveness of biorefinery products.
Enzymatic hydrolysis of lignocellulose feedstocks has been observed as the rate-limiting stage during anaerobic digestion. This necessitated the need for pretreatment before anaerobic digestion for an effective and efficient process. Therefore, this study investigated the impact of acidic pretreatment on Arachis hypogea shells, and different conditions of H2SO4 concentration, exposure time, and autoclave temperature were considered. The substrates were digested for 35 days at a mesophilic temperature to assess the impact of pretreatment on the microstructural organization of the substrate. For the purpose of examining the interactive correlations between the input parameters, response surface methodology (RSM) was used. The result reveals that acidic pretreatment has the strength to disrupt the recalcitrance features of Arachis hypogea shells and make them accessible for microorganisms' activities during anaerobic digestion. In this context, H2SO4 with 0.5\% v. v-1 for 15 min at an autoclave temperature of 90 degrees C increases the cumulative biogas and methane released by 13 and 178\%, respectively. The model's coefficient of determination (R2) demonstrated that RSM could model the process. Therefore, acidic pretreatment poses a novel means of total energy recovery from lignocellulose feedstock and can be investigated at the industrial scale.
Acacia dealbata wood (an invasive species) was subjected to fractionation with glycerol (a cheap industrial by- product), and the resulting solid phase was used as a substrate for enzymatic hydrolysis. Glycerol fractionation allowed an extensive delignification while preserving cellulose in solid phase. The solids from the fractionation stage showed high susceptibility to enzymatic hydrolysis. Solids obtained under selected fractionation conditions (glycerol content of media, 80 wt\%; duration, 1 h; liquid to solid ratio, 6 g/g; alkaline and neutral washing stages) were subjected to enzymatic saccharification to achieve glucose concentrations up to 85.40 g/L, with almost complete cellulose conversion into glucose. The results confirmed the potential of glycerol as a fractionation agent for biorefineries. (C) 2014 Elsevier Ltd. All rights reserved.
A headspace solid-phase microextraction method with subsequent GC-MS (HS-SPME/GC-MS) was established for the quantitative analysis of volatile lignin derived phenolic monomers in complex aqueous solutions. Extraction was done using a polyacrylate fiber. The optimization of HS-SPME - parameters was performed using a multi component model solution of six representative phenolic monomers identified in liquid hot water (LHW) supernatants of hydrothermally treated lignocellulosic biomass: p-coumaric acid, guaiacol, vanillin, acetosyringone, 4-hydroxy-3-methoxyphenylacetone, and acetophenone. Plackett-Burman design was applied for pre-evaluation and 2(3) central composite designs with star points for parameter optimization. LOQ(S/N > 10) and LOD (S/N > 3) were determined for 12 phenols yielding LOQ of <0.005-618 nM and LOD of <0.005-412 nM. Within-day and between-day tests (n = 6) showed different results for the tested phenols. RSD ranged from 2\% to 30\% and recovery rates from 99\% to 160\% in LHW matrix. Tests on storage of LHW supernatants for several weeks indicated a considerable influence of temperature on the stability of the solutions which may even have to be taken into account for auto sampler handling. All in all the method allows a fast and solvent free analysis requiring low sample volumes making it a powerful tool for screening or high-throughput analysis of aqueous solutions of lignin derived aromatics. (C) 2013 Published by Elsevier B.V.
Development of an efficient pretreatment strategy to breakdown recalcitrant lignocellulosic biomass is a crucial prerequisite for commercial success of second generation ethanol production. Pretreatment using organic solvents has huge potential to release maximum sugars from the biomass. This study showed that the modified organosolv pretreatment using high boiling point glycerol solvent and ammonia as catalyst significantly improved the saccharification yield from sorghum (Sorghum bicolor (L.) Moench) biomass. The addition of ammonia as a catalyst helped in improving the xylan recovery with partial lignin removal and reduced the severity of the pretreatment process. The optimum concentrations of glycerol and ammonia for pretreatment were found to be 51.11\% (w/w) and 5.14\% (w/w), respectively, using response surface optimization methodology. The saccharification of biomass pretreated with the optimized concentration of solvent at 120 degrees C for 1 h resulted in a maximum total sugars of 421.35 mg/g. Crude glycerol, being the byproduct of biodiesel industry, could be used as a cheaper solvent for the process. The ammoniacal glycerol pretreatment of a variety of feedstocks showed high efficiency of hydrolysis of cellulose and xylan. Simultaneous hydrolysis and cofermentation (SSCF) of the ammoniacal glycerol pretreated biomass using fed-batch strategy for 20\% (w/w) solids loading gave maximum ethanol concentration of 36 g/L. Low cellulase CTec2 dose of 4 U/g solid was used to hydrolyze 20\% (w/w) solids loading along with the addition of xylanase and polyethylene glycol (PEG), which gave maximum reported cellulose digestibility of 72\% for sorghum biomass. Thus, ammoniacal glycerol pretreatment using crude glycerol improved the sugar and ethanol yield from sorghum biomass, benefiting both biodiesel and bioethanol industry.
Lignocellulose is the main component of plants and has a wide range of sources. The high-value production of lignocellulose lies in the biorefinery of lignin, cellulose and hemicellulose. The ad-vantages and disadvantages of traditional lignocellulose pretreatment methods were summarized, and the effective pretreatment parameters were listed. As a green solvent system with excellent performance, deep eutectic solvents (DES) are considered to be the most potential biomass pre-treatment system. Based on this, the new trend and progress of DES in lignocellulose pretreatment were reviewed, focusing on the effects of distinct kinds of lignocellulose raw materials, distinct components of DES, distinct reaction conditions and assisted by microwave ultrasound on the pre-treatment of lignocellulose, and the recyclability of DES solution system was discussed. Finally, the application and development direction of DES in lignocellulose pretreatment are proposed and prospected.
When applied to soils, it is unclear whether and how biochar can affect soil nutrients. This has implications both to the availability of nutrients to plants or microbes, as well as to the question of whether biochar soil amendment may enhance or reduce the leaching of nutrients. In this work, a range of laboratory experiments were conducted to determine the effect of biochar amendment on sorption and leaching of nitrate, ammonium, and phosphate in a sandy soil. A total of thirteen biochars were tested in laboratory sorption experiments and most of them showed little/no ability to sorb nitrate or phosphate. However, nine biochars could remove ammonium from aqueous solution. Biochars made from Brazilian pepperwood and peanut hull at 600 degrees C (PH600 and BP600, respectively) were used in a column leaching experiment to assess their ability to hold nutrients in a sandy soil. The BP600 biochar effectively reduced the total amount of nitrate, ammonium, and phosphate in the leachates by 34.0\%, 34.7\%, and 20.6\%, respectively, relative to the soil alone. The PH600 biochar also reduced the leaching of nitrate and ammonium by 34\% and 14\%, respectively, but caused additional phosphate release from the soil columns. These results indicate that the effect of biochar on the leaching of agricultural nutrients in soils is not uniform and varies by biochar and nutrient type. Therefore, the nutrient sorption characteristics of a biochar should be studied prior to its use in a particular soil amendment project. (C) 2012 Elsevier Ltd. All rights reserved.
The biological delignification of lignocellulosic feedstocks, Prosopis juliflora and Lantana camara was carried out with Pycnoporus cinnabarinus, a white rot fungus, at different scales under solid-state fermentation (SSF) and the fungal treated substrates were evaluated for their acid and enzymatic saccharification. The fungal fermentation at 10.0 g substrate level optimally delignified the P. juliflora by 11.89\% and L. camara by 8.36\%, and enriched their holocellulose content by 3.32 and 4.87\%, respectively, after 15 days. The fungal delignification when scaled up from 10.0 g to 75.0, 200.0 and 500.0 g substrate level, the fungus degraded about 7.69-10.08\% lignin in P. juliflora and 6.89-7.31\% in L. camara, and eventually enhanced the holocellulose content by 2.90-3.97 and 4.25-4.61\%, respectively. Furthermore, when the fungal fermented L. camara and P. juliflora was hydrolysed with dilute sulphuric acid, the sugar release was increased by 21.4-42.4\% and the phenolics content in hydrolysate was decreased by 18.46 and 19.88\%, as compared to the unfermented substrate acid hydrolysis, respectively. The reduction of phenolics in acid hydrolysates of fungal treated substrates decreased the amount of detoxifying material (activated charcoal) by 25.0-33.0\% as compared to the amount required to reduce almost the same level of phenolics from unfermented substrate hydrolysates. Moreover, an increment of 21.1-25.1\% sugar release was obtained when fungal treated substrates were enzymatically hydrolysed as compared to the hydrolysis of unfermented substrates. This study clearly shows that fungal delignification holds potential in utilizing plant residues for the production of sugars and biofuels.
Most of the corn-ethanol plants use dry-mill process and generate large volume of distillers dried grains with solubles (DDGS) as the co-product. The DDGS is a promising feedstock with rich content of cellulose and xylan. The goal of this study was to optimize cellulase and xylanase production byTrichoderma reesei(NRRL 6156) using DDGS as the carbon source at shake-flask and validate the results at benchtop bioreactors. The fermentation medium containing varied amounts of dilute-acid pretreated DDGS, yeast extract, and peptone were optimized for maximal enzyme production at 30 degrees C, pH 5.0 and 180 rpm with 3\% (v/v) inoculum using Box-Behnken response surface methodology (RSM). Co-production of xylanase and cellulase enzymes was not achieved in the same medium; higher DDGS hydrolysate favored cellulase enzyme only while lower amount induced the xylanase enzyme. Based on the RSM results, maximal xylanase of 18.5 IU/mL was predicted with 5\% DDGS hydrolysate, 0.1 g/L yeast extract, and 2 g/L peptone, while maximal cellulase of 1.1 IU/mL was predicted with 20\% DDGS hydrolysate, 1 g/L yeast extract, and 0.5 g/L peptone. Of the two developed models from shake-flasks, xylanase model validated successfully the fermenter results giving 18.7 IU/mL of experimental xylanase in 1.5-L working volume bioreactor. {[
Supercritical water gasification (SCWG) of Enteromorpha intestinalis (E. intestinalis) as a major algal biomass of southern coast of Caspian Sea was investigated in a batch reactor with and without the catalyst, to determine its potential for hydrogen production. The highest hydrogen yield of 5.25 (mmol H-2/g of E. intestinalis) was observed for the noncatalytic test in the temperature of 440 degrees C, water loading of 6 g, E. intestinalis loading of 0.06 g and reaction time of 10 min. All catalytic tests were performed in this condition in the presence of unpromoted and ruthenium promoted Ni-Fe/gamma-Al2O3 nanocatalysts. Catalysts were prepared with 12 wt.\% of Ni and 6 wt.\% of Fe in the active phase and 0.5-2 wt.\% of Ru as a promoter via microemulsion technique. Nanocatalysts were characterized by ICP, BET, XRD, H-2 chemisorption, and TEM techniques to recognize their physicochemical properties. According to catalyst characterizations, the promoted Ni-Fe/gamma-Al2O3 with 2 wt.\% Ru with higher dispersion and smaller size of nickel on gamma-Al2O3, showed the best performance during SCWG of E. intestinalis. The maximum 1-12 yield of 12.28 (mmol H-2/g of E. intestinalis) and hydrogen selectivity of 0.74, were obtained by using this optimized catalyst. (C) 2016 Elsevier Ltd. All rights reserved.
Production of ethanol by bioconversion of lignocellulosic biomass has attracted much interest in recent years. However, the pretreatment process for increasing the enzymatic digestibility of cellulose has become a key step in commercialized production of cellulosic ethanol. During the last decades, many pretreatment processes have been developed for decreasing the biomass recalcitrance, but only a few of them seem to be promising. From the point of view for integrated utilization of lignocellulosic biomass, organosolv pretreatment provides a pathway for biorefining of biomass. This review presents the progress of organosolv pretreatment of lignocellulosic biomass in recent decades, especially on alcohol, organic acid, organic peracid and acetone pretreatments, and corresponding action mechanisms. Evaluation and prospect of organosolv pretreatment were performed. Finally, some recommendations for future investigation of this pretreatment method were given.
In recent years, there has been an increasing interest in finding alternative material to replace fossil-oil based product due to the environmental concern. Lignocellulosic biomass has emerged as the promising candidate due to its low-cost and sustainability. The objective of this work was to prepare cellulose nanofibers (CNFs) from empty palm fruit bunches (EPFB), which are the waste originating from palm oil industry. Cellulose fibers were first extracted from EPFB by chemical treatment, followed by mechanical disintegration using high-pressure homogenization. Fiber concentration and defibrillation time during mechanical treatment were studied to investigate their effects on the properties of produced nanofibers. The obtained micro- and nano-fibers were characterised using Fourier transform infrared spectroscopy (FTIR), X-ray diffmctometer (XRD), Thermogravimetric analyzer (TGA), Scanning electron microscope (SEM) and Transmission electron microscope (TEM). The results indicated that non-cellulosic components were successfully removed by chemical treatment, as evidenced by the disappearance of lignin and hemicellulose related peaks in FTIR analysis, reduction of their content in chemical composition result, and increase in the thermal stability for purified fibers. Moreover, TEM images and diameter distribution analysis revealed that fiber concentration of 0.5\%w/v provided the best diameter size uniformity with the nanofiber's diameter ranged 6 inn to 16 mn, as compared to higher fiber concentration.
Oat hulls are a promising feedstock annually renewable at an industrial scale for the production of second generation ethanol. Chemical pretreatment of oat hulls with a 4\% (wow) nitric acid solution at atmospheric pressure was performed in pilot production to give a pulp in which hydrolyzables account for 79.9\%. Acid-insoluble lignin totaling 12.5\% in the pulp does not deteriorate the efficiency of enzymatic hydrolysis using an enzyme cocktail of commercial BrewZyme BGX and CelloLux-A. At an initial solid loading of 33.3 g/L, a hydrolyzate was obtained with a reducing sugar yield of 93.0\% of the overall hydrolyzables. The high yield is assured only by removal of residual, water-soluble, nitrated lignin by water washing. Alcoholic fermentation was run using Saccharomyces cerevisiae Y-1693. Simultaneous saccharification and fermentation with delayed inoculation (dSSF) at an initial pulp loading of 90 g/L was found to improve the ethanol yield by 1.2 times compared to separate hydrolysis and fermentation (SHF), i.e. 0.428 versus 0.343 g/g cellulose, respectively. The ethanol samples obtained from oat hulls contain low percentages of esters and methanol. (C) 2016 Elsevier B.V. All rights reserved.
This paper presents a feasibility study on the effects of forest based ash (FBA) on the mechanical performance of concrete. Four such samples were obtained from the pulp and paper industry as the residual byproduct of their hog fuel. They were analyzed for grain size distribution, density, morphology, and oxide content. Subsequently, the ash was employed as a cement substitute (up to 20\% by mass) and the resulting concrete was examined for mechanical properties. Results show that all four FBA samples were coarser than Portland cement with mean particle size around 100-1000 microns. Further, X-ray fluorescence showed that the FBA samples were predominantly composed of CaO, with significant amounts of SO3 and alkali oxides at levels that exceed maximum limits allowed for the latter by ASTM. This poses concerns on durability. Nevertheless, based on short-term compressive and tensile performance alone, this study shows that FBA could replace up to 15\% by mass of cement.
In this study, pinewood and corn stover pretreated with the ionic liquid (IL) 1-allyl-3-methylimidazolium chloride (AmimCl) were used as a feedstock for succinic acid production. Results reveal that 5\% (v/v) AmimCl inhibited bacterial growth, whereas 0.01\% (v/v) AmimCl inhibited succinic acid production. AmimCl was effective in extracting cellulose from pinewood and in degrading pinewood into a uniform pulp, as revealed by scanning electron microscopy (SEM). The rate of enzymatic hydrolysis of pinewood extract reached 72.16\%. The combinations of AmimCl pretreatment with steam explosion or with hot compressed water were effective in treating corn stover, whereas AmimCl treatment alone did not result in a significant improvement. Pinewood extract produced 20.7 g/L succinic acid with an average yield of 0.37 g per gram of biomass. Workflow calculations indicated pine wood pretreated with IL has a theoretical yield of succinic acid of 57.1\%. IL pretreatment led to increase in succinic acid yields. (C) 2014 Elsevier Ltd. All rights reserved.
The lignocellulosic material of mushroom farm waste was used as a feedstock owing to its quantity and availability in Taiwan. In the first stage, the lignocellulosic material of mushroom farm waste was converted into reduced sugars using concentrated sulfuric acid via hydrolysis with a one-step and/or a two-step process. The reduced sugars were then recovered by anion exchange resin. In the second stage, reduced sugars from the first stage were used as substrate to test the potential for biohydrogen production in a batch system. The effects of sulfuric acid concentrations, reaction temperature, particle size, and two-step hydrolysis were investigated at the first pretreatment stage (mushroom farm waste hydrolysis). The reduced sugar concentrations and the initial pH were investigated in the second stage (biohydrogen production). It was found that the maximum yield of reduced sugars in hydrolyzate (reduced sugar per soluble cellulose, wt\%) from the first-step (40 degrees C for 20 mm with 55.0\% acid) and the second-step (40 degrees C for 20 min with 6.9\% acid) were 74.49\% and 96.79\%, respectively. In the second stage, the best hydrogen production yield and the hydrogen production rate were 2.52 mol H-2/g COD substrate and 4.38 L/L/d, respectively, were obtained initially with a pH 7.0, a temperature of 37 degrees C and initial reduced sugar concentration of 20 g of COD/L. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.