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Helene Carrere - One of the best experts on this subject based on the ideXlab platform.
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Mild microwaves, ultrasonic and alkaline Pretreatments for improving methane production: Impact on biochemical and structural properties of olive pomace
Bioresource Technology, 2020Co-Authors: Doha Elalami, Helene Carrere, Diana Garcia-bernet, Karima Abdelouahdi, Jérôme Peydecastaing, Guadalupe Vaca-medina, Abdallah Oukarroum, Youssef Zeroual, Abdellatif BarakatAbstract:This study aims to investigate the effects of microwaves, ultrasonic and alkaline Pretreatments on olive pomace properties and its biomethane potential. Alkaline Pretreatment was found to reduce lipid and fiber contents (especially lignin) and to increase soluble matter. The alkali Pretreatment at a dose of 8% under 25°C and for 1 day (w/w TS) removed 96% of initial lipids from the solid olive pomace. Unlike NaOH addition, mild microwaves and ultrasonic Pretreatments had no impact on lignin. However, in the case of long microwaves Pretreatment (450W-10 min), cellulose and lignin contents were reduced by 50% and 26% respectively. Similarly, the combination of ultrasonic and alkali reagent showed a positive effect on fiber degradation and lipid solubilization as well as a positive impact on methane production. Statistical analysis highlighted the correlation between NaOH dose, solubilization and methane production. The alkaline Pretreatment at ambient temperature appeared the most energetically efficient.
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How can Pretreatments overcome the limitations of the main solid feedstock anaerobic digestion?
2019Co-Authors: Helene Carrere, Audrey Battimelli, Ivet FerrerAbstract:Pretreatment technologies for improving the anaerobic digestion of solid wastes have been intensively investigated during the last decade. Manure, sludge and the organic fraction of municipal solid wastes (OFMSW) are among the most studied anaerobic digestion solid feedstock. Indeed, there has been an exponential increase in the number of publications including the Pretreatment of solid feedstock like sludge, manure and OFMSW, but also lignocellulosic biomass and algae. Clearly the most appropriate Pretreatment depends on the properties of each feedstock. In the case of sludge, Pretreatments are intended to release intracellular compounds, being biological, thermal and mechanical technologies already applied at full-scale. Lignocellulosic biomass requires delignification and cellulose solubilisation, achieved through biological, chemical and /or mechanical methods. Manure Pretreatments are generally biological (i.e. composting) or mechanical. As far as animal by-products are concerned, thermal Pretreatments are compulsory to ensure sanitation, but mechanical ones are also applied.
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Efficency of alkaline Pretreatment of sorghum and miscanthus before batch dry codigestion with cattle manure
2018Co-Authors: Hélène Thomas, Renaud Escudié, Jean-philippe Delgenès, Helene CarrereAbstract:Agricultural biogas sector is currently facing fast development in France, and cattle manure which is rich in straw constitutes an important feedstock available in an agricultural context. Cattle manure is characterized by a total solid content of about 20-30 %, and it is thus suited to dry anaerobic digestion. Among the available technologies, batch dry digesters processes with leachate spreading are particularly interesting for small-scale biogas plants. However, the start-up of these plants is quite slow in reason of low hydrolysis rate of cattle manure, and codigestion represents a good option to facilitate the start-up phase. In this study, sorghum and miscanthus were considered for codigestion with manure, because these energy crops present the advantages of high biomass yields and low inputs requirements (water, fertilizers). In addition miscanthus can grow on polluted soils whereas sorghum can be cultivated as catch crops. Nevertheless carbohydrates accessibility of these lignocellulosic biomasses is limited and may be improved before anaerobic digestion processes by alkali Pretreatments. As a consequence, the objective of this study was to evaluate the efficiency of alkali Pretreatments of sorghum and miscanthus to improve the start-up phase and the reactor performance when codigested with cattle manure. Experiments were carried out in 6 L leach bed reactors (LBR), fed with 300 g TS of organic substrate and 1.1 L leachate. The substrate/inoculum ratio was 6 (gVS/gVS) by adding a digestate sampled in a previous batch, and the substrate was composed of 85% (in wet weight basis) of manure and 15% of sorghum or miscanthus (corresponding to 39-40%VS of sorghum or miscanthus). Two different Pretreatments were applied at room temperature, with low water addition (to reach 13%TS) and no mixing: soda (NaOH, 10g/100 gTS, 1 day) Pretreatment for sorghum only, lime Pretreatment (10g/100 gTS, for 5 days) for sorghum and miscanthus. The pretreated substrates as well as the raw ones without Pretreatment (controls) were digested in LBR in duplicates during two different runs. After 57 days of sorghum codigestion, the highest methane production was obtained for NaOH- Pretreatment with a methane yield of 232 ± 15 mL/gVS, corresponding to an increase of 20 % and 11% compared to the control and CaO-treated sorghum, respectively. However, during the start-up phase of the batch process, soda Pretreatment was less efficient than lime Pretreatment because, within 6 first days, the highest methane production (61 ± 1 mL/gVS) was obtained for lime-pretreated sorghum (43 ± 22 mL/gVS and 25 ± 16 mL/gVS for soda-pretreated sorghum and untreated sorghum, respectively). In fact, soda Pretreatment led to a transient acidification phase with an accumulation of volatile fatty acid (VFA) concentration up to 9.3 g/L on days 2-3, which slowed down the methanogenic activity. In contrast, maximum VFA concentrations were 6.8 g/L and 6.5 g/L for lime pretreated sorghum and raw sorghum, respectively. Leachate pH did not fall under 6.48 thanks to the presence of alkali, which may have mitigated the negative effect of VFA accumulation. Concerning the codigestion of miscanthus with cattle manure, lower methane production than codigestion with sorghum was observed: 158 ± 4 mL/gVS after 59 days for untreated miscanthus. Lime pretreatement led to only a 6 % increase in methane production. A slightly higher impact (+8%) was observed on methane production after 6 days. Lower accumulation of VFA was observed than for sorghum reactors (e.g., 5 g/L after 1 day for lime pretreated miscanthus). In conclusion, alkali Pretreatment of sorghum and miscanthus before their batch codigestion with manure showed a slight positive impact on reactor performances. Soda Pretreatment led to a higher acidification risk during the start-up phase. Associated with the detrimental impact of sodium on agricultural soils in the case of digestate land spreading, lime Pretreatment is recommended.
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Biological Pretreatments of biomass for improving biogas production: an overview from lab scale to full-scale
Renewable and Sustainable Energy Reviews, 2018Co-Authors: Ulysse Bremond, Jean-philippe Steyer, Raphaëlle De Buyer, Nicolas Bernet, Helene CarrereAbstract:Recent shifts in European countries biogas policies tend to limit the use of energy crops and encourage the use of manure, lignocellulosic feedstocks and bio-waste. The need to use feedstocks that are more difficult to handle (displaying either too low or too high biodegradation rates) is calling for the development of adapted Pretreatments. Among them, biological Pretreatments are very promising due to their reasonable cost, environmental friendliness and possible application to a wide spectrum of feedstocks. They can be divided into three categories: enzymatic, anaerobic and aerobic ones. This review aims at providing some guidelines on which type of biological Pretreatment to apply for a given feedstock. To deliver such recommendations we considered the full range of technological readiness level. We gathered an analysis of the recent literature data obtained at lab or pilot scale focusing on methane yield enhancements and the description of some full-scale commercialized technologies. For lignocellulosic feedstocks, both enzymatic Pretreatments using lignin-modifying enzymes or carbohydrases and aerobic Pretreatments using consortia or simple aeration appear as promising. For bio-waste, anaerobic Pretreatment via two-stage digestion seems to be an efficient biological Pretreatment. For landfill, enzymatic treatment may be an interesting solution. Finally, for sludge digestion, both aerobic and anaerobic Pretreatments favouring autohydrolysis may be recommended. Full-scale applications already exist but their use remains scarce. Indeed, each biological Pretreatment features technological issues. Enzymes have high production costs and limited activity in time. Anaerobic Pretreatments, notably two-stage digestion, are more expensive and complex to handle than a single stage. Finally, aerobic Pretreatments need fine tuning and control due to respiration mass loss. Research and development conducted toward these specific issues may allow these Pretreatments to become more cost-effective as well as practical and thus facilitate their development at full-scale.
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Improvement of anaerobic degradation by white-rot fungi Pretreatment of lignocellulosic biomass: A review
Renewable and Sustainable Energy Reviews, 2016Co-Authors: E. Rouches, I. Herpoël-gimbert, Jean-philippe Steyer, Helene CarrereAbstract:Anaerobic digestion of lignocellulosic biomass appears to be an efficient process for the production of energy whilst answering present-day environmental challenges. However, lignin contained in lignocellulosic biomass is hardly biodegradable, thus representing a major obstacle for maximum methane production. Consequently, although Pretreatments need to be considered, their cost is a limit for their full-scale use. Biological Pretreatments are a cheaper alternative in this context. Several biological Pretreatments have been studied for anaerobic digestion: Ensiling, partial composting, specific microbial consortia, enzymes and fungi. Simple, inexpensive and efficient Pretreatments can be obtained using fungi. White-rot fungi (WRF), have been considered as most capable of delignifying a substrate. However, their use in the Pretreatment of substrates for anaerobic digestion is quite recent and still needs to be investigated. This review compares fungal Pretreatment with other biological treatments for anaerobic digestion of lignocellulosic biomass. Enzymatic mechanisms for WRF Pretreatments are then exposed. The literature data regarding the improvement of anaerobic digestibility with WRF Pretreatment are summarized (anaerobic digestion and in vitro digestibility with rumen microorganisms). Finally, lignocellulosic biomass features allowing the improvement of anaerobic digestion are exposed (porosity, cellulose crystallinity, etc.). The possible effects of WRF on these characteristics are discussed and industrial perspectives for WRF Pretreatments are presented.
Brigitte Chabbert - One of the best experts on this subject based on the ideXlab platform.
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Changes in Phenolics Distribution After Chemical Pretreatment and Enzymatic Conversion of Miscanthus × giganteus Internode
BioEnergy Research, 2013Co-Authors: Nassim Belmokhtar, Anouck Habrant, N. Lopes Ferreira, Brigitte ChabbertAbstract:In addition to lignin, grass cell walls are characterized by the presence of hydroxycinnamic acids that play a significant role in cross-linking polymers into a cohesive network, and Pretreatments are required to overcome the recalcitrance of lignocelluloses prior to enzymatic bioconversion of polysaccharides. The effects of dilute acid and ammonium hydroxide Pretreatments were studied on the chemical composition and enzymatic saccharification of Miscanthus internodes fragments. The hydroxycinnamic acid content was reduced after both Pretreatments, while lignin got enriched in condensed linked structures. In addition, dilute acid Pretreatment was effective in decreasing xylan content of Miscanthus , while ammonia treatment induced a marked swelling effect on the cell walls of parenchyma, vascular sclerenchyma, and epidermal sclerenchyma. The phenol distribution at the cell level was estimated using UV transmission microspectrophotometry. Internode cell walls displayed different UV spectra according to the cell type. However, the secondary cell walls had similar UV spectra after Pretreatment, whereas spectra recorded at the cell corner region displayed variations according to cell type and Pretreatment. Acid Pretreatment was more efficient than ammonia to improve the conversion of polysaccharides by a Trichoderma cellulolytic cocktail. Although Pretreatments achieved moderate saccharification yields, the secondary cell walls were altered at some pit regions of the vascular sclerenchyma whereas parenchyma appeared recalcitrant. Variations in the UV spectra of enzyme-digested cell walls suggest Pretreatment-dependent heterogeneity of the phenolic distribution in the more recalcitrant cell walls.
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Changes in Phenolics Distribution After Chemical Pretreatment and Enzymatic Conversion of Miscanthus x giganteus Internode
BioEnergy Research, 2013Co-Authors: Nassim Belmokhtar, Anouck Habrant, N. Lopes Ferreira, Brigitte ChabbertAbstract:In addition to lignin, grass cell walls are characterized by the presence of hydroxycinnamic acids that play a significant role in cross-linking polymers into a cohesive network, and Pretreatments are required to overcome the recalcitrance of lignocelluloses prior to enzymatic bioconversion of polysaccharides. The effects of dilute acid and ammonium hydroxide Pretreatments were studied on the chemical composition and enzymatic saccharification of Miscanthus internodes fragments. The hydroxycinnamic acid content was reduced after both Pretreatments, while lignin got enriched in condensed linked structures. In addition, dilute acid Pretreatment was effective in decreasing xylan content of Miscanthus, while ammonia treatment induced a marked swelling effect on the cell walls of parenchyma, vascular sclerenchyma, and epidermal sclerenchyma. The phenol distribution at the cell level was estimated using UV transmission microspectrophotometry. Internode cell walls displayed different UV spectra according to the cell type. However, the secondary cell walls had similar UV spectra after Pretreatment, whereas spectra recorded at the cell corner region displayed variations according to cell type and Pretreatment. Acid Pretreatment was more efficient than ammonia to improve the conversion of polysaccharides by a Trichoderma cellulolytic cocktail. Although Pretreatments achieved moderate saccharification yields, the secondary cell walls were altered at some pit regions of the vascular sclerenchyma whereas parenchyma appeared recalcitrant. Variations in the UV spectra of enzyme-digested cell walls suggest Pretreatment-dependent heterogeneity of the phenolic distribution in the more recalcitrant cell walls.
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combination of ammonia and xylanase Pretreatments impact on enzymatic xylan and cellulose recovery from wheat straw
Bioresource Technology, 2010Co-Authors: Caroline Remond, Nathalie Aubry, David Cronier, S Noel, F Martel, Barbara Rogé, Harivony Rakotoarivonina, Philippe Debeire, Brigitte ChabbertAbstract:Abstract Soaking in aqueous ammonia (SSA) and/or xylanase Pretreatments were developed on wheat straw. Both Pretreatments were conducted at high-solids conditions: 15% and 20%, respectively, for SSA and xylanase Pretreatments. SSA pretreament led to the solubilisation of 38%, 12% and 11% of acid insoluble lignin, xylan and glucan, respectively. In case of xylanase Pretreatment, 20% of xylan were removed from native wheat straw. When Pretreatments were applied consecutively (SSA and xylanase) on straw, 56% of xylans were hydrolysed and a rapid reduction of media viscosity occurred. The enzymatic hydrolysis of cellulose with cellulases was evaluated from the different combinations of pretreated wheat straw. Cellulose hydrolysis was improved by 2.1, 2.2 and 2.9, respectively, for xylanase, SSA and SSA/xylanase pretreated straw. Xylans from untreated and pretreated wheat straws were also solubilised with cellulases. Chemical analysis of pretreated straw residues in connection with yields of cellulose hydrolysis highlighted the role of phenolic acids, acetyl content and cellulose crystallinity for cellulase efficiency.
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Combination of ammonia and xylanase Pretreatments: impact on xylan and cellulose recovery from wheat straw
Bioresource Technology, 2010Co-Authors: Caroline Remond, Nathalie Aubry, David Cronier, S Noel, F Martel, Barbara Rogé, Harivony Rakotoarivonina, Philippe Debeire, Brigitte ChabbertAbstract:Soaking in aqueous ammonia (SSA) and/or xylanase Pretreatments were developed on wheat straw. Both Pretreatments were conducted at high-solids conditions: 15% and 20%, respectively, for SSA and xylanase Pretreatments. SSA pretreament led to the solubilisation of 38%, 12% and 11% of acid insoluble lignin, xylan and glucan, respectively. In case of xylanase Pretreatment, 20% of xylan were removed from native wheat straw. When Pretreatments were applied consecutively (SSA and xylanase) on straw, 56% of xylans were hydrolysed and a rapid reduction of media viscosity occurred. The enzymatic hydrolysis of cellulose with cellulases was evaluated from the different combinations of pretreated wheat straw. Cellulose hydrolysis was improved by 2.1, 2.2 and 2.9, respectively, for xylanase, SSA and SSA/xylanase pretreated straw. Xylans from untreated and pretreated wheat straws were also solubilised with cellulases. Chemical analysis of pretreated straw residues in connection with yields of cellulose hydrolysis highlighted the role of phenolic acids, acetyl content and cellulose crystallinity for cellulase efficiency.
Charles E. Wyman - One of the best experts on this subject based on the ideXlab platform.
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Flowthrough Pretreatment with very dilute acid provides insights into high lignin contribution to biomass recalcitrance
Biotechnology for Biofuels, 2016Co-Authors: Samarthya Bhagia, Rajeev Kumar, Hongjia Li, Charles E. WymanAbstract:Background Flowthrough Pretreatment is capable of removing much higher quantities of hemicellulose and lignin from lignocellulosic biomass than batch Pretreatment performed at otherwise similar conditions. Comparison of these two Pretreatment configurations for sugar yields and lignin removal can provide insights into lignocellulosic biomass deconstruction. Therefore, we applied liquid hot water (LHW) and extremely dilute acid (EDA, 0.05%) flowthrough and batch Pretreatments of poplar at two temperatures and the same Pretreatment severity for the solids. Composition of solids, sugar mass distribution with Pretreatment, sugar yields, and lignin removal from Pretreatment and enzymatic hydrolysis were measured. Results Flowthrough aqueous Pretreatment of poplar showed between 63 and 69% lignin removal at both 140 and 180 °C, while batch Pretreatments showed about 20 to 33% lignin removal at similar conditions. Extremely dilute acid slightly enhanced lignin removal from solids with flowthrough Pretreatment at both Pretreatment temperatures. However, extremely dilute acid batch Pretreatment did realize greater than 70% xylan yields largely in the form of monomeric xylose. Close to 100% total sugar yields were measured from LHW and EDA flowthrough Pretreatments and one batch EDA Pretreatment at 180 °C. The high lignin removal by flowthrough Pretreatment enhanced cellulose digestibility compared to batch Pretreatment, consistent with lignin being a key contributor to biomass recalcitrance. Furthermore, solids from 180 °C flowthrough Pretreatment were much more digestible than solids pretreated at 140 °C despite similar lignin and extensive hemicellulose removal. Conclusions Results with flowthrough Pretreatment show that about 65–70% of the lignin is solubilized and removed before it can react further to form low solubility lignin rich fragments that deposit on the biomass surface in batch operations and hinder enzyme action. The leftover 30–35% lignin in poplar was a key player in biomass recalcitrance to enzymatic deconstruction and it might be more difficult to dislodge from biomass with lower temperature of Pretreatment. These results also point to the possibility that hemicellulose removal is more important as an indicator of lignin disruption than in playing a direct role in reducing biomass recalcitrance.
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Comparison of changes in cellulose ultrastructure during different Pretreatments of poplar
Cellulose, 2014Co-Authors: Qining Sun, Charles E. Wyman, Marcus Foston, Daisuke Sawada, Sai Venkatesh Pingali, Hugh M. O’neill, Paul Langan, Arthur J RagauskasAbstract:One commonly cited factor that contributes to the recalcitrance of biomass is cellulose crystallinity. The present study aims to establish the effect of several Pretreatment technologies on cellulose crystallinity, crystalline allomorph distribution, and cellulose ultrastructure. The observed changes in the cellulose ultrastructure of poplar were also related to changes in enzymatic hydrolysis, a measure of biomass recalcitrance. Hot-water, organo-solv, lime, lime-oxidant, dilute acid, and dilute acid-oxidant Pretreatments were compared in terms of changes in enzymatic sugar release and then changes in cellulose ultrastructure measured by ^13C cross polarization magic angle spinning nuclear magnetic resonance and wide-angle X-ray diffraction. Pretreatment severity and relative chemical depolymerization/degradation were assessed through compositional analysis and high-performance anion-exchange chromatography with pulsed amperometric detection. Results showed minimal cellulose ultrastructural changes occurred due to lime and lime-oxidant Pretreatments, which at short residence time displayed relatively high enzymatic glucose yield. Hot water Pretreatment moderately changed cellulose crystallinity and crystalline allomorph distribution, yet produced the lowest enzymatic glucose yield. Dilute acid and dilute acid-oxidant Pretreatments resulted in the largest increase in cellulose crystallinity, para -crystalline, and cellulose-I_β allomorph content as well as the largest increase in cellulose microfibril or crystallite size. Perhaps related, compositional analysis and Klason lignin contents for samples that underwent dilute acid and dilute acid-oxidant Pretreatments indicated the most significant polysaccharide depolymerization/degradation also ensued. Organo-solv Pretreatment generated the highest glucose yield, which was accompanied by the most significant increase in cellulose microfibril or crystallite size and decrease in relatively lignin contents. Hot-water, dilute acid, dilute acid-oxidant, and organo-solv Pretreatments all showed evidence of cellulose microfibril coalescence.
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sugar yields from dilute oxalic acid Pretreatment of maple wood compared to those with other dilute acids and hot water
Carbohydrate Polymers, 2013Co-Authors: Taiying Zhang, Rajeev Kumar, Charles E. WymanAbstract:Abstract Dilute oxalic acid Pretreatment was applied to maple wood to improve compatibility with downstream operations, and its performance in Pretreatment and subsequent enzymatic hydrolysis was compared to results for hydrothermal and dilute hydrochloric and sulfuric acid Pretreatments. The highest total xylose yield of ∼84% of the theoretical maximum was for both 0.5% oxalic and sulfuric acid Pretreatment at 160 °C, compared to ∼81% yield for hydrothermal Pretreatment at 200 °C and for 0.5% hydrochloric acid Pretreatment at 140 °C. The xylooligomer fraction from dilute oxalic acid Pretreatment was only 6.3% of the total xylose in solution, similar to results with dilute hydrochloric and sulfuric acids but much lower than the ∼70% value for hydrothermal Pretreatment. Combining any of the four Pretreatments with enzymatic hydrolysis with 60 FPU cellulase/g of glucan plus xylan in the pretreated maple wood resulted in virtually the same total glucose plus xylose yields of ∼85% of the maximum possible.
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comparative data on effects of leading Pretreatments and enzyme loadings and formulations on sugar yields from different switchgrass sources
Bioresource Technology, 2011Co-Authors: Charles E. Wyman, Bruce E. Dale, Venkatesh Balan, Yoon Y Lee, Michael R Ladisch, Richard T Elander, Mark T Holtzapple, Matthew Falls, Bonnie Hames, Nathan S MosierAbstract:Dilute sulfuric acid (DA), sulfur dioxide (SO2), liquid hot water (LHW), soaking in aqueous ammonia (SAA), ammonia fiber expansion (AFEX), and lime Pretreatments were applied to Alamo, Dacotah, and Shawnee switchgrass. Application of the same analytical methods and material balance approaches facilitated meaningful comparisons of glucose and xylose yields from combined Pretreatment and enzymatic hydrolysis. Use of a common supply of cellulase, beta-glucosidase, and xylanase also eased comparisons. All Pretreatments enhanced sugar recovery from Pretreatment and subsequent enzymatic hydrolysis substantially compared to untreated switchgrass. Adding beta-glucosidase was effective early in enzymatic hydrolysis while cellobiose levels were high but had limited effect on longer term yields at the enzyme loadings applied. Adding xylanase improved yields most for higher pH Pretreatments where more xylan was left in the solids. Harvest time had more impact on performance than switchgrass variety, and microscopy showed changes in different features could impact performance by different Pretreatments.
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Chapter 4:Dilute Acid and Hydrothermal Pretreatment of Cellulosic Biomass
Energy and Environment Series, 2011Co-Authors: Deepti Tanjore, Jian Shi, Charles E. WymanAbstract:Biomass Pretreatment remains one of the most pressing challenges in terms of cost-effective production of biofuels. We present a short summary of Pretreatments that re based on dilute acid and water. Water-only and dilute acid Pretreatments can be effective in producing sugars from hemicellulose along with a solid residue enriched in cellulose that can be digested to glucose with high yields. Generally speaking, dilute acid is often favored because it realizes higher yields than water alone and produces mostly monomeric sugars, but water-only Pretreatment can reduce the consequences of hydrolyzate conditioning to remove inhibitors, employ lower cost reaction vessels, and avoid the challenges of adding acid. The performance of water-only systems correlates well with the severity parameter, while the modified severity parameter is an effective tool in analyzing dilute acid performance. Kinetic models have also been applied to describe sugar release profiles from dilute acid Pretreatments, with the parameters fit to match the data, but the models are not robust in terms of a’ priori predictions of performance. Feedstock features can have a significant effect on performance, with lignin amounts and makeup and mineral contents having potentially large effects. Economic studies clearly show that Pretreatment is an expensive operation with pervasive impacts on the costs of other steps. Thus, although dilute acid and water-only Pretreatments appear to be frontrunners currently, much more must be done to understand and advance Pretreatment technologies to realize really low costs and high yields that are essential to production of commodity products.
Jean-philippe Steyer - One of the best experts on this subject based on the ideXlab platform.
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Biological Pretreatments of biomass for improving biogas production: an overview from lab scale to full-scale
Renewable and Sustainable Energy Reviews, 2018Co-Authors: Ulysse Bremond, Jean-philippe Steyer, Raphaëlle De Buyer, Nicolas Bernet, Helene CarrereAbstract:Recent shifts in European countries biogas policies tend to limit the use of energy crops and encourage the use of manure, lignocellulosic feedstocks and bio-waste. The need to use feedstocks that are more difficult to handle (displaying either too low or too high biodegradation rates) is calling for the development of adapted Pretreatments. Among them, biological Pretreatments are very promising due to their reasonable cost, environmental friendliness and possible application to a wide spectrum of feedstocks. They can be divided into three categories: enzymatic, anaerobic and aerobic ones. This review aims at providing some guidelines on which type of biological Pretreatment to apply for a given feedstock. To deliver such recommendations we considered the full range of technological readiness level. We gathered an analysis of the recent literature data obtained at lab or pilot scale focusing on methane yield enhancements and the description of some full-scale commercialized technologies. For lignocellulosic feedstocks, both enzymatic Pretreatments using lignin-modifying enzymes or carbohydrases and aerobic Pretreatments using consortia or simple aeration appear as promising. For bio-waste, anaerobic Pretreatment via two-stage digestion seems to be an efficient biological Pretreatment. For landfill, enzymatic treatment may be an interesting solution. Finally, for sludge digestion, both aerobic and anaerobic Pretreatments favouring autohydrolysis may be recommended. Full-scale applications already exist but their use remains scarce. Indeed, each biological Pretreatment features technological issues. Enzymes have high production costs and limited activity in time. Anaerobic Pretreatments, notably two-stage digestion, are more expensive and complex to handle than a single stage. Finally, aerobic Pretreatments need fine tuning and control due to respiration mass loss. Research and development conducted toward these specific issues may allow these Pretreatments to become more cost-effective as well as practical and thus facilitate their development at full-scale.
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Improvement of anaerobic degradation by white-rot fungi Pretreatment of lignocellulosic biomass: A review
Renewable and Sustainable Energy Reviews, 2016Co-Authors: E. Rouches, I. Herpoël-gimbert, Jean-philippe Steyer, Helene CarrereAbstract:Anaerobic digestion of lignocellulosic biomass appears to be an efficient process for the production of energy whilst answering present-day environmental challenges. However, lignin contained in lignocellulosic biomass is hardly biodegradable, thus representing a major obstacle for maximum methane production. Consequently, although Pretreatments need to be considered, their cost is a limit for their full-scale use. Biological Pretreatments are a cheaper alternative in this context. Several biological Pretreatments have been studied for anaerobic digestion: Ensiling, partial composting, specific microbial consortia, enzymes and fungi. Simple, inexpensive and efficient Pretreatments can be obtained using fungi. White-rot fungi (WRF), have been considered as most capable of delignifying a substrate. However, their use in the Pretreatment of substrates for anaerobic digestion is quite recent and still needs to be investigated. This review compares fungal Pretreatment with other biological treatments for anaerobic digestion of lignocellulosic biomass. Enzymatic mechanisms for WRF Pretreatments are then exposed. The literature data regarding the improvement of anaerobic digestibility with WRF Pretreatment are summarized (anaerobic digestion and in vitro digestibility with rumen microorganisms). Finally, lignocellulosic biomass features allowing the improvement of anaerobic digestion are exposed (porosity, cellulose crystallinity, etc.). The possible effects of WRF on these characteristics are discussed and industrial perspectives for WRF Pretreatments are presented.
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Improvement of anaerobic degradation by white-rot fungi Pretreatment of lignocellulosic biomass : A review
Renewable and Sustainable Energy Reviews, 2016Co-Authors: E. Rouches, Jean-philippe Steyer, Herpoël-gimbert I, Carrere HAbstract:Anaerobic digestion of lignocellulosic biomass appears to be an efficient process for the production of energy whilst answering present-day environmental challenges. However, lignin contained in lignocellulosic biomass is hardly biodegradable, thus representing a major obstacle for maximum methane production. Consequently, although Pretreatments need to be considered, their cost is a limit for their full-scale use. Biological Pretreatments are a cheaper alternative in this context. Several biological pre-treatments have been studied for anaerobic digestion: ensiling, partial composting, specific microbial consortia, enzymes and fungi. Simple, inexpensive and efficient Pretreatments can be obtained using fungi. White-rot fungi (WRF), have been considered as most capable of delignifying a substrate. However, their use in the Pretreatment of substrates for anaerobic digestion is quite recent and still needs to be investigated. This review compares fungal Pretreatment with other biological treatments for anaerobic digestion of lignocellulosic biomass. Enzymatic mechanisms for WRF Pretreatments are then exposed. The literature data regarding the improvement of anaerobic digestibility with WRF Pretreatment are summarized (anaerobic digestion and in vitro digestibility with rumen microorganisms). Finally, lignocellulosic biomass features allowing the improvement of anaerobic digestion are exposed (porosity, cellulose crystallinity, etc.). The possible effects of WRF on these characteristics are discussed and industrial perspectives for WRF Pretreatments are presented. (C) 2016 Elsevier Ltd. All rights reserved.
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comparison of seven types of thermo chemical Pretreatments on the structural features and anaerobic digestion of sunflower stalks
Bioresource Technology, 2012Co-Authors: Florian Monlau, Jean-philippe Steyer, Abdellatif Barakat, Helene CarrereAbstract:Abstract Sunflower stalks can be used for the production of methane, but their recalcitrant structure requires the use of thermo-chemical Pretreatments. Two thermal (55 and 170 °C) and five thermo-chemical Pretreatments (NaOH, H 2 O 2 , Ca(OH) 2 , HCl and FeCl 3 ) were carried out, followed by anaerobic digestion. The highest methane production (259 ± 6 mL CH 4 g −1 VS) was achieved after Pretreatment at 55 °C with 4% NaOH for 24 h. Acidic Pretreatments at 170 °C removed more than 90% of hemicelluloses and uronic acids whereas alkaline and oxidative Pretreatments were more effective in dissolving lignin. However, no Pretreatment was effective in reducing the crystallinity of cellulose. Methane production rate was positively correlated with the amount of solubilized matter whereas methane potential was negatively correlated with the amount of lignin. Considering that the major challenge is obtaining increased methane potential, alkaline Pretreatments can be recommended in order to optimize the anaerobic digestion of lignocellulosic substrates.
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Biogas from lignocellulosic biomass : interest of Pretreatments
2011Co-Authors: Helene Carrere, Florian Monlau, Abdellatif Barakat, Claire Dumas, Jean-philippe SteyerAbstract:Biomass deconstruction processes have been extensively studied as pretreatement of enzymatic hydrolysis of cellulose for second generation bioethanol production. This paper proposes to review these processes with a special attention on their impact on biomass structure and characteristics and to discuss the interest of using them as Pretreatment to enhance anaerobic digestion of lignocellulosic compounds. Studies showing the performance of Pretreatments on biogas production from lignocellulosic biomass are also rewieved.
Bruce E. Dale - One of the best experts on this subject based on the ideXlab platform.
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Low Temperature and Long Residence Time AFEX Pretreatment of Corn Stover
BioEnergy Research, 2012Co-Authors: Bryan D. Bals, Farzaneh Teymouri, Tim Campbell, Mingjie Jin, Bruce E. DaleAbstract:Low temperature and long residence time Pretreatments have been proposed as an alternative to conventional Pretreatments within a centralized biorefinery, allowing for a decentralized Pretreatment without high energy costs. Ammonia fiber expansion (AFEX™) Pretreatment may be uniquely suitable for decentralized Pretreatment, and this study considers the possibility of decreasing the temperature in AFEX Pretreatment of corn stover. AFEX Pretreatment at 40°C and 8 h produced comparable sugar and ethanol yields as conventional AFEX Pretreatment at high temperatures and short residence time during subsequent hydrolysis and fermentation. Increasing the ammonia loading at these temperatures tends to increase digestibility, although the moisture content of the reaction has little effect. This study suggests a greater flexibility in AFEX Pretreatment conditions than previously thought, allowing for an alternative approach for decentralized facilities if the economic conditions are appropriate.
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comparative material balances around Pretreatment technologies for the conversion of switchgrass to soluble sugars
Bioresource Technology, 2011Co-Authors: Rebecca J Garlock, Bruce E. Dale, Venkatesh Balan, Ramesh V Pallapolu, Yoon Y Lee, Youngmi Kim, Nathan S Mosier, Michael R LadischAbstract:For this project, six chemical Pretreatments were compared for the Consortium for Applied Fundamentals and Innovation (CAFI): ammonia fiber expansion (AFEX), dilute sulfuric acid (DA), lime, liquid hot water (LHW), soaking in aqueous ammonia (SAA), and sulfur dioxide (SO2). For each Pretreatment, a material balance was analyzed around the Pretreatment, optional post-washing step, and enzymatic hydrolysis of Dacotah switchgrass. All Pretreatments + enzymatic hydrolysis solubilized over two-thirds of the available glucan and xylan. Lime, post-washed LHW, and SO2 achieved >83% total glucose yields. Lime, post-washed AFEX, and DA achieved >83% total xylose yields. Alkaline Pretreatments, except AFEX, solubilized the most lignin and a portion of the xylan as xylo-oligomers. As Pretreatment pH decreased, total solubilized xylan and released monomeric xylose increased. Low temperature-long time or high temperature-short time Pretreatments are necessary for high glucose release from late-harvest Dacotah switchgrass but high temperatures may cause xylose degradation.
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comparative data on effects of leading Pretreatments and enzyme loadings and formulations on sugar yields from different switchgrass sources
Bioresource Technology, 2011Co-Authors: Charles E. Wyman, Bruce E. Dale, Venkatesh Balan, Yoon Y Lee, Michael R Ladisch, Richard T Elander, Mark T Holtzapple, Matthew Falls, Bonnie Hames, Nathan S MosierAbstract:Dilute sulfuric acid (DA), sulfur dioxide (SO2), liquid hot water (LHW), soaking in aqueous ammonia (SAA), ammonia fiber expansion (AFEX), and lime Pretreatments were applied to Alamo, Dacotah, and Shawnee switchgrass. Application of the same analytical methods and material balance approaches facilitated meaningful comparisons of glucose and xylose yields from combined Pretreatment and enzymatic hydrolysis. Use of a common supply of cellulase, beta-glucosidase, and xylanase also eased comparisons. All Pretreatments enhanced sugar recovery from Pretreatment and subsequent enzymatic hydrolysis substantially compared to untreated switchgrass. Adding beta-glucosidase was effective early in enzymatic hydrolysis while cellobiose levels were high but had limited effect on longer term yields at the enzyme loadings applied. Adding xylanase improved yields most for higher pH Pretreatments where more xylan was left in the solids. Harvest time had more impact on performance than switchgrass variety, and microscopy showed changes in different features could impact performance by different Pretreatments.
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The impacts of Pretreatment on the fermentability of pretreated lignocellulosic biomass: a comparative evaluation between ammonia fiber expansion and dilute acid Pretreatment
Biotechnology for Biofuels, 2009Co-Authors: Ming W Lau, Christa Gunawan, Bruce E. DaleAbstract:Background Pretreatment chemistry is of central importance due to its impacts on cellulosic biomass processing and biofuels conversion. Ammonia fiber expansion (AFEX) and dilute acid are two promising Pretreatments using alkaline and acidic pH that have distinctive differences in Pretreatment chemistries. Results Comparative evaluation on these two Pretreatments reveal that (i) AFEX-pretreated corn stover is significantly more fermentable with respect to cell growth and sugar consumption, (ii) both Pretreatments can achieve more than 80% of total sugar yield in the enzymatic hydrolysis of washed pretreated solids, and (iii) while AFEX completely preserves plant carbohydrates, dilute acid Pretreatment at 5% solids loading degrades 13% of xylose to byproducts. Conclusion The selection of Pretreatment will determine the biomass-processing configuration, requirements for hydrolysate conditioning (if any) and fermentation strategy. Through dilute acid Pretreatment, the need for hemicellulase in biomass processing is negligible. AFEX-centered cellulosic technology can alleviate fermentation costs through reducing inoculum size and practically eliminating nutrient costs during bioconversion. However, AFEX requires supplemental xylanases as well as cellulase activity. As for long-term sustainability, AFEX has greater potential to diversify products from a cellulosic biorefinery due to lower levels of inhibitor generation and lignin loss.
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the impacts of Pretreatment on the fermentability of pretreated lignocellulosic biomass a comparative evaluation between ammonia fiber expansion and dilute acid Pretreatment
Biotechnology for Biofuels, 2009Co-Authors: Ming W Lau, Christa Gunawan, Bruce E. DaleAbstract:Background Pretreatment chemistry is of central importance due to its impacts on cellulosic biomass processing and biofuels conversion. Ammonia fiber expansion (AFEX) and dilute acid are two promising Pretreatments using alkaline and acidic pH that have distinctive differences in Pretreatment chemistries.
