Subcritical Water Pretreatment Research Articles

Bioethanol Production from Paper Sludge by Subcritical Water Pretreatment and Semi-simultaneous Saccharification and Fermentation

Bioethanol Production from Paper Sludge by Subcritical Water Pretreatment and Semi-simultaneous Saccharification and Fermentation

INFLUENCE OF SUBCRITICAL WATER PRETREATMENT TEMPERATURE ON PINEAPPLE WASTE BIOGAS EFFICIENCY: EXPERIMENTAL AND KINETIC STUDY

Anaerobic digestion of pineapple waste appears to be an effective method for non-renewable energy substitution through biogas production. The potential power generation from the exploitation of pineapple waste as fuel is estimated to be roughly 20.8 MW. Nevertheless, the intricate composition of pineapple waste, characterized by the complex arrangement of its structure, poses a significant challenge in attaining a substantial amount of biogas production. This study pretreated pineapple waste with subcritical water to increase biogas production. Two temperature settings (120⁰C and 200⁰C) were used for pretreatment. Combined pre-treatment at low temperatures and short time (120⁰C, 5 minutes, 10 water to solid ratio) resulted in 31.6% higher biogas production than untreated. However, pretreatment at high temperatures and longer reaction time (200⁰C,25 min) reduced the biogas production by 9% as compared to untreated. Using the Modified Gompertz kinetic model, pretreatment improved the lag phase and increased biogas production to 14.41 mL/day. The lignocellulosic composition of pre-treated pineapple waste decreased, while process parameters such as total ammonia nitrogen removal and pH improved after the pretreatment. Subcritical water pretreatment, particularly when conducted at high temperatures, did not yield any enhancements in the anaerobic digestion of pineapple waste. As a result, it is not advisable to employ this method for these purposes.

Subcritical Water Pretreatment for Anaerobic Digestion Enhancement: A Review

This work reviews hydrothermal subcritical water pretreatment to enhance biogas production through anaerobic digestion. The complexity of the lignocellulosic structure has been the main limitation contributing to unsatisfactory biogas production throughout the anaerobic digestion. The high resistance of the structure to biological hydrolysis has increased the interest in applying pretreatment prior to anaerobic digestion to facilitate hydrolysis. Hydrothermal subcritical water technology, an environmentally friendly pretreatment that uses water as the main medium, is gaining prominence in biogas enhancement. However, the subcritical water pretreatment influence on structural properties, biogas production, and the production of anaerobic process inhibitors signifies a knowledge gap and needs an evaluation. This review presents the need for pretreatment reaction and properties in the subcritical water region, biogas production from subcritical water pre-treated waste, production of inhibitors, and its challenges are discussed. This pretreatment could be a promising option and further enhance biogas production throughout the anaerobic digestion process.

Rapid production of organic fertilizer using subcritical water treatment on waste biomass

Waste biomass are highly valuable and have potential to be converted to organic fertilizers or compost. This is a great alternative to replace the uses of commercial chemical fertilizers towards sustainable agriculture. However, due to its complex molecular structure and high lignin content, it hinders full decomposition of these wastes into mature compost. Therefore, subcritical water (SCW) pre-treatment was studied to enhance the hydrolytic degradation of biomass waste such as rice straw, banana peel, and chicken feathers to be converted into mature compost within a shorter time. Validation on the maturity of the treated substrates and measurements of the level of phytotoxicity in the compost were studied based on the germination index (GI) of Japanese mustard seeds. Results showed that all treated substrates provided high GI of more than 60% at its optimum concentration which indicates the significant contribution of SCW pre-treatment to produce effective mature compost.

Subcritical Water Pretreatment for the Efficient Valorization of Sorghum Distillery Residue for the Biorefinery Platform.

The depletion of fossil fuels is resulting in an increased energy crisis, which is leading the paradigm shift towards alternative energy resources to overcome the issue. Lignocellulosic biomass or agricultural residue could be utilized to produce energy fuel (bioethanol) as it can resolve the issue of energy crisis and reduce environmental pollution that occurs due to waste generation from agriculture and food industries. A huge amount of sorghum distillery residue (SDR) is produced during the Kaoliang liquor production process, which may cause environmental problems. Therefore, the SDR generated can be utilized to produce bioethanol to meet current energy demands and resolve environmental problems. Using a central composite experimental design, the SDR was subjected to hydrothermal pretreatment. The conditions selected for hydrothermal pretreatment are 155 °C, 170 °C, and 185 °C for 10, 30, and 50 min, respectively. Based on the analysis, 150 °C for 30 min conditions for SDR hydrothermal pretreatment were selected as no dehydration product (Furfural and HMF) was detected in the liquid phase. Therefore, the pretreated slurry obtained using hydrothermal pretreatment at 150 °C for 30 min was subjected to enzymatic hydrolysis at 5% solid loading and 15 FPU/gds. The saccharification yield obtained at 72 h was 75.05 ± 0.5%, and 5.33 g/L glucose concentration. This non-conventional way of enzymatic hydrolysis eliminates the separation and detoxification process, favoring the concept of an economical and easy operational strategy in terms of biorefinery.

Subcritical water pretreatment enhanced methane-rich biogas production from the anaerobic digestion of brewer’s spent grains

ABSTRACT This study evaluated the effectiveness of a semi-continuous flow-through subcritical water hydrolysis (SWH) pretreatment of brewer’s spent grains (BSG) for subsequent application in the anaerobic digestion (AD) process. BSG pretreatment was conducted at 160 °C and 15 MPa with a flow rate of 10 mL water min−1 and 15 g water g−1 BSG. The results revealed that SWH attacked the hemicellulose structure, releasing arabinose (46.54 mg g–1) and xylose (39.90 mg g–1) sugars, and proteins (34.89 mg g–1). The start-up of anaerobic reactors using pretreated BSG (747.71 L CH4 kg−1 TVS) increased the methane yield compared with the reactor without pretreatment (53.21 L CH4 kg−1 TVS). For the process with pretreatment, the generation of electricity (134 kWh t−1 BSG) and heat (604 MJ t−1) are responsible for the mitigation of 43.90 kg CO2 eq t−1 BSG. The adoption of SWH as an eco-friendly pretreatment of biomass for AD could be a technological route to increase methane-rich biogas and bioenergy production, supporting the circular economy transition by reducing the carbon footprint of the beer industry.

Subcritical Water as Pretreatment Technique for Bioethanol Production from Brewer's Spent Grain within a Biorefinery Concept.

Bioeconomy and environmental issues envisage industrial by-products such as Brewer's spent grain (BSG) as renewable resources for their recycling and reuse within a biorefinery concept. This study aimed to investigate the production of bioethanol from subcritical water (subW) pretreated BSG, following the conversion of the BSG biopolymers cellulose and hemicelluloses. The subW pretreatment was performed in a batch reactor at 174 °C, during 60 min and 5% (w/v) of dry BSG charge. The behavior of BSG biopolymers under subW pretreatment was monitored by evaluating the chemical composition of the liquid and solid streams and the chemical and structural changes caused in the solid residues by scanning electron microscope (SEM), CHNS elemental analysis and water retention value (WRV). The production of bioethanol from subW-pretreated BSG was assessed by separate hydrolysis and fermentation (SHF) and also by simultaneous saccharification and fermentation (SSF) by using the enzymatic cocktail Celluclast 1.5 L (40 FPU/gsolids) and the yeast Ethanol Red®. The higher bioethanol productivity (1.073 g∙L-1∙h-1) and concentration (32.18 g/L) were achieved by SSF with higher solids' loading (25%) and following a fed-batch strategy. These results suggest that subcritical water pretreatment is a promising technology for the valorization of BSG as a feedstock for second-generation bioethanol production.

Sustainable bioprocess combining subcritical water pretreatment followed by anaerobic digestion for the valorization of jabuticaba (Myrciaria cauliflora) agro-industrial by-product in bioenergy and biofertilizer

The management of agri-food by-products has received worldwide attention due to concerns about the environmental impacts caused by incorrect deposition. This study presented a sustainable bioprocess combining subcritical water pretreatment (SWP) followed by semi-continuous anaerobic digestion (AD) for the valorization of jabuticaba (Myrciaria cauliflora) agro-industrial by-product in bioenergy and agricultural fertilizer. The SWP was conducted at 180 °C, 15 MPa, water flow rate of 10 mL min−1, solvent to feed of 22.5 g g−1, and a kinetic time of 45 min. The AD process was operated in semi-continuous mode under mesophilic and methanogenic conditions. The results demonstrated that the hydrolysate presented glucose (5.78 g L−1), fructose (3.63 g L−1), arabinose (1.82 g L−1), and cellobiose (1.28 g L−1) as major compounds. The use of pretreated jabuticaca by-product increased the methane yield (239.04 L CH4 kg−1 TVS) in the designed bioprocess combining SWP and AD when compared to the AD without pretreatment (42.31 L CH4 kg−1 TVS). The methane produced in the bioprocess with SWP followed by AD can generate 543 kWh t−1 of electricity and 2,243.17 MJ t−1 of heat, avoiding a total of 177.54 kg CO2-eq t−1. The digestate generated after AD can be used as a biofertilizer up to a concentration of 0.3 g L−1, without toxic effects on the germination of Lactuca sativa. Finally, the sustainable bioprocess designed could be an alternative to the management of jabuticaba by-product within a circular economy framework, producing bioenergy and agricultural fertilizer that can reduce greenhouse gas emissions and environmental pollution in the food industry.

Direct consolidated bioprocessing for d-glucaric acid production from lignocellulose under subcritical water pretreatment

d-glucaric acid production from lignocellulose is a valuable research field, but meets the same challenge as other biorefinery processes that prevents it from commercialization, high production costs. The very path to tackle this is to increase the titer, rate and yield (TRY) of d-glucaric acid production and simplify the process, on which this study focused. Herein we used a novel, clean and environmentally friendly pretreatment, subcritical water pretreatment (SCWP), based on which we compared consolidated bioprocessing (CBP) by the microbial consortium composed of Trichoderma reesei C10 and Saccharomyces cerevisiae LGA-1C3S2 with separated hydrolysis and fermentation (SHF). CBP was found to be advantageous over SHF because of its comparable yield, much more simplified bioprocess and bigger space for cost reduction. Then CBP was upgraded to direct consolidated bioprocessing (dCBP) by adapting the microbial consortium in the raw liquors of SCWP containing inhibitors and toxic chemicals. As a result, more integrated biorefinery processes from corn stover (CS), wheat straw (WS), rice straw (RS) and switchgrass (SG) to d-glucaric acid under SCWP were developed and scaled up from shake flasks to 10 L fermenters, stirred and airlift. The TRYs of d-glucaric acid were improved significantly. The airlift fermenter was preferable for the dCBPs, producing the highest concentrations of d-glucaric acid, which were 10.03 g/L from subcritical water pretreated CS (SWCPCS), 9.53 g/L from SWCPWS, 8.87 g/L from SWCPRS and 10.66 g/L from SWCPSG respectively. Subsequently, the dCBPs were coupled with the downstream separation to establish a closed-circuit circulation and 30 rounds was run successfully. The highly integrated process from lignocellulose to d-glucaric acid with the smallest number of single unit operations was obtained and reported for the first time, providing an important design for biorefinery. This work is of great significance for biomanufacturing d-glucaric acid and other bio-based chemicals.

Full components conversion of lignocellulose via a closed-circuit biorefinery process on a pilot scale

This study developed a closed-circuit biorefinery process for full conversion of lignocellulose into ethanol, biogas and organic fertilizer with zero waste on a pilot scale. In the process, subcritical water pretreatment could effectively break the structure of wheat straw (WS), and ethanol was obtained from pretreated wheat straw (PWS) using two batches of simultaneous saccharification and fermentation (SSF). The pretreatment and ethanol fermentation wastes were reused for biogas and organic fertilizer production by anaerobic digestion (AD), whereas the pretreatment and ethanol conversion efficiency were reduced when supernatant after AD was recovered for next batch pretreatment. The yields of ethanol (0.08–0.09 g/g), biogas (0.05–0.10 L/g) and organic fertilizer (0.55–0.79 g/g) were demonstrated through mass balance. Furthermore, the hidden problems were exposed on pilot-scale conversion process, and several strategies were provided for optimizing the biorefinery process in the future.

Optimization of subcritical water pre-treatment for biogas enhancement on co-digestion of pineapple waste and cow dung using the response surface methodology

The optimal pre-treatment method and conditions depend on the types of lignocellulose present due to the complexity and the variability of biomass chemical structures. This study optimized subcritical water pre-treatment to ensure maximum methane production from pineapple waste prior to anaerobic co-digestion with cow dung using the response surface methodology. A central composite design was achieved with three different factors and one response. A total of 20 pre-treatment runs were performed at different temperatures, reaction times and water to solid ratios suggesting optimum values for subcritical water pre-treatment at 128.52℃ for 5 min with 5.67 to 1 water to solid ratio. Under these conditions, methane yield increased from 59.09 to 85.05 mL CH4/g VS with an increase of 23% biogas yield and 44% methane yield from the untreated. All pre-treatments above 200℃ showed reductions in biogas yield. Compositional analysis showed slight reduction of lignin and increase in α-cellulose content after the pre-treatment. Analysis using Fourier transform infrared spectroscopy and thermogravimetric analysis verified the presence of cellulosic material in pre-treated pineapple waste. Most of the hemicellulose was solubilized in the liquid samples after SCW pre-treatment. The crystallinity index of pineapple waste was reduced from 57.58% (untreated) to 54.29% (pre-treated). Scanning electron microscopy confirmed the structural modification of pre-treated pineapple waste for better microbial attack. Subcritical water pre-treatment is feasible as a promising method to enhance the anaerobic co-digestion process. Further study should be conducted to assess the scale-up of the process from pre-treatment to anaerobic digestion at the pilot plant level.

Impact of surfactant-aided subcritical water pretreatment process conditions on the reducing sugar production from oil palm empty fruit bunch

Oil palm empty fruit bunch (OPEFB), waste produced from the palm oil mills, has not been intensely utilized while its abundant availability in tropical countries such as Indonesia. It is one of the potential lignocellulosic material sources which can be utilized to produce sugar. The subcritical water process has been known as a promising lignocellulose-to-sugar conversion process. This study examined the effects of temperature, surfactant types, and concentrations on the sugar yield from OPEFB through the subcritical water process. In this research, the subcritical water process was conducted at a varied temperature of 140-180 °C, constant pressure and time of 60 bar, and 60 minutes, respectively. The types of surfactants studied were non-ionic, anionic, and cationic (Tween 80, SDS, and CTAB). Reducing sugar concentration analyses and solid characterizations using SEM, XRD, FTIR, and TGA were carried out in this research to evaluate the impact of the subcritical water process variables. The experiments showed that Tween 80 addition to the subcritical water process produced significant sugar yields at temperature 140 °C. The addition of CTAB to the subcritical water process shows adverse effects, while that of SDS showed support in the sugar production yields. This may be caused by hydrophobic and hydrophilic interactions between functional groups of the lignin unit and the hydrophobic and ionic groups of the surfactants. The subcritical water process run at a temperature of 180 °C assisted by SDS is the best scenario to produce the highest reducing sugar yield of 4.034%.

Cost analysis of subcritical water pretreatment of sugarcane straw and bagasse for second‐generation bioethanol production: a case study in a sugarcane mill

AbstractThe value of lignocellulose residues for green technologies has been growing, but biomass pretreatment is still an economic challenge. In this case study, a cost analysis of subcritical water pretreatment (SCWP) of sugarcane by‐products for ethanol production was conducted. The proposed industrial scheme is attached to a Brazilian sugarcane mill, which generates a surplus of bagasse. Seven scenarios were simulated to address the prospects of the implementation of the process in the mill. The fermentation of sugarcane bagasse hydrolysate with Scheffersomyces stipitis upgraded the ethanol yield. The fixed capital investment of the industrial process was approximately US$27 million and 35% of this was associated with the SCWP. The highest ethanol yield was obtained for the process operated with hydrolysate from sugarcane bagasse (6740.5 kg ethanol day−1), which is associated with the high hemicellulose content in the bagasse composition compared with straw. The cost difference revealed that the fixed capital investment and utilities were the largest expenses for process implementation and operation. The simulated process reached 5.45 US$ L−1 as the lowest cost of manufacturing. However, this cost is approximately 10‐fold higher than the market price for ethanol in Brazil. In conclusion, the SCWP of sugarcane straw and bagasse demands significant technical improvement before scaling up to the industrial scale for bioethanol production. © 2021 Society of Chemical Industry and John Wiley & Sons, Ltd

Characteristics of antibiotic resistance genes in full-scale anaerobic digesters of food waste and the effects of application of biogas slurry on soil antibiotic resistance genes.

The fate of antibiotic resistance genes (ARGs) in full-scale anaerobic digestion (AD) of food waste (FW) and in the soil applied with biogas slurry has not been fully understood. In this study, 12 targeted ARGs and intI1 in FW, intermediate product, and biogas slurry from three full-scale ADwere analyzed. The results showed that subcritical water pretreatment was aneffective method for ARG attenuation, by which the absolute abundance of total targeted ARGs was removed by 99.69%. The predominant ARGs (ermB, tetM, and tetW) in FW were removed more than 99% after subcritical water pretreatment. The result of field experiments with biogas slurry as fertilizer showed that the absolute abundance of several ARGs (sul2, tetM, blaOXA-1, blaTEM) and intI1 accumulated significantly compared to the control group (CK) during three consecutive growth stages of the rice. The detected abundance of ARGs in paddy field soil increased from 190.50 (CK) to 8.87 × 104 copies/g (wet weight) (soil) during tillering stage, and increased from 4102.65 (CK) to 4.38 × 104 copies/g (wet weight) (soil) during heading time. Biogas slurry improved the soil nutrients (TN, AN, TP, and AP); meanwhile, the concentrations of total salt and Cl- increased. Network analysis indicated that 28 genera were the possible hosts of ARGs; variation partitioning analysis (VPA) indicated that microbial communities (contribution 59.30%) were the main factors that affected the fate of ARGs and intI1.

Microwave subcritical water pre-treatment and enzymatic hydrolysis of geographical identification (GI) tag Indian black rice (Chakhao Poireiton) straw for fermentable sugar production

Rice straw is an important feedstock for second-generation biorefineries, the majority being conventional white rice. This research investigated the potential of the straw of black rice Chakhao Poireiton, a rice variety of increasing importance, for biorefining. Pre-treatment of black rice straw was carried out in a pressurised microwave reactor and free sugar release was measured following digestion with Cellic® CTec3. This was compared to white rice straw. Pre-treatment (100 − 200° C for 5 min) did not drastically impact the sugar composition but brought about an enhanced release of glucose after enzymatic hydrolysis from 25 to 50% (black rice) and from 26 to 55% (white rice). For xylose digestibility, the increase was around seven-fold for black rice (8 to 57%) and five-fold for white rice (13 to 64%). This improvement in digestibility of the straw samples could have come from modification in the lignocellulose structural features making the polysaccharides more susceptible to hydrolysis. Black rice could be a suitable feedstock for a combined biorefinery – food and nutraceuticals from grain (much higher than white rice) and the straw for fermentable sugars comparable to white rice straw for biofuels.

Subcritical water pretreatment for agave bagasse fractionation from tequila production and enzymatic susceptibility

This work focuses on the effect of subcritical water pretreatment conditions on agave bagasse chemical composition, biomass fractionation, and enzymatic hydrolysis obtained from the different tequila production processes. The pretreatment was carried out in a batch pressurized reactor within an isothermal regime. The operational conditions for subcritical water pretreatment were (150–190 °C) and (10–50 min). The best operational conditions were selected, based on the increased cellulose content (>50%) in the pretreated solid phase. The conditions for 190 °C for 50 and 30 min of pretreated agave bagasse solids were chosen for enzymatic hydrolysis susceptibility (15 FPU/g of the substrate). The maximum conversion yield (cellulose to glucose) during enzymatic hydrolysis achieved was up to 61.62% (5.86 g/L) in industrial bagasse at 72 h and initial saccharification rate was 0.34 g/(L*h) at 12 h. This study indicates that the agave bagasse is a promising raw material in the development of second-generation biorefineries.

Cellulose fibers extracted from sesame hull using subcritical water as a pretreatment

Sesame processing facilities typically discard sesame seed hulls (SH) as waste or animal feed. However, these hulls are rich in cellulose and make them potentially valuable to the food industry. This study for the first time studied the effect of subcritical water (SW) and alkali (AT) pretreatment on extraction of purified cellulose from SH. The results indicated that the yield of SWCs (cellulose obtained by subcritical water pretreatment, 9.2–11.6%) was close to that of ATC (cellulose obtained by alkali pretreatment, 10.1%). Crystallinity of SWCs (68.7–75.8%) was significantly higher than ATC (60.9%). Subcritical water pretreatments interfered more significantly than alkali with the removal of non-cellulosic components according to Fourier transform infrared spectrometry and scanning electron microscope photographs. In addition, the diameter of the SWC was smaller than ATC, and the obtained SWC was comparable to ATC in terms of thermal stability. This study shows that subcritical water, as an environmentally friendly solvent, can be used to extract good quality cellulose from SH. In addition, subcritical water is more effective than alkali, suggesting it could be used more widely in the food industry for producing cellulose from other sources.

Integrating enzymatic hydrolysis into subcritical water pretreatment optimization for bioethanol production from wheat straw

The conversion of lignocellulosic biomass to bioethanol is a potential approach to alleviate the energy crisis and environmental deterioration. To improve the conversion efficiency of bioethanol from wheat straw (WS), the optimization of subcritical water pretreatment and high solid hydrolysis were investigated in this study. Response surface methodology (RSM) accompanied with glucose concentration after enzymatic hydrolysis as a more reasonable response value was applied for the pretreatment optimization, and the optimum conditions were obtained as 220.51 °C of extraction temperature, 22.01 min of extraction time and 2.50% (w/v) of substrate loading. After pretreatment, the hemicellulose decreased by 18.37%, and the cellulose and lignin increased by 25.92% and 8.81%, respectively, which were consistent with the destroyed microstructure and raised crystallinity. The high efficiency of separate hydrolysis and fermentation (SHF) was verified by five commercial cellulases, and yields of hydrolysis and fermentation were 77.85–89.59% and 93.34–96.18%, respectively. Based on the high solid (15%) hydrolysis and fermentation, the ethanol concentration was significantly improved to 37.00 g/L. Interestingly, 64.47% of lignin was accumulated in the solid residue after enzymatic hydrolysis and it did not affect the efficiency of SHF, which further suggested that subcritical water mainly affected the structure of WS rather than the removal of lignin. Therefore, subcritical water pretreatment combined with high solid hydrolysis is a more effective solution for bioethanol conversion, which is also a promising strategy to utilize all components of lignocellulosic biomass.

Physicochemical characteristics of chitosan from swimming crab (Portunus trituberculatus) shells prepared by subcritical water pretreatment

The physicochemical properties of chitosan obtained from the shells of swimming crab (Portunus trituberculatus) and prepared via subcritical water pretreatment were examined. At the deacetylation temperature of 90 °C, the yield, ash content, and molecular weight of chitosan in the shells prepared via subcritical water pretreatment were 12.2%, 0.6%, and 1187.2 kDa, respectively. These values were lower than those of shells prepared via sodium hydroxide pretreatment. At the deacetylation temperature of 120 °C, a similar trend was observed in chitosan molecular weight, but differences in chitosan yield and ash content were not remarkable. At the same deacetylation temperature, the structures of chitosan prepared via sodium hydroxide and subcritical water pretreatments were not substantially different. However, the compactness and thermal stability of chitosan prepared via sodium hydroxide pretreatment was lower than those of chitosan prepared via subcritical water pretreatment. Compared with the chitosan prepared by sodium hydroxide pretreatment, the chitosan prepared by subcritical water pretreatment was easier to use in preparing oligosaccharides, including (GlcN)2, via enzymatic hydrolysis with chitosanase. Results suggested that subcritical water pretreatment can be potentially used for the pretreatment of crustacean shells. The residues obtained via this method can be utilized to prepare chitosan.

Ozonolysis of wheat bran in subcritical water for enzymatic saccharification and polysaccharide recovery

The destarched wheat bran was pretreated with ozonolysis, subcritical water (SW), and their combinations to improve its enzymatic digestion and hemicellulose solubilization. Ozonolysis caused lignin destructions and partial leach of hemicelluloses, leading to the formation of oxalic acids. Taking advantage of these effects, the sequential combinations of ozonolysis and SW showed synergy, resulting in a 3-fold hydrolysis outcome relative to the individual SW treatment. Eventually, the combined pretreatment achieved a high hemicellulose removal (86%) and saccharification yield (85% for glucose) under a mild SW condition (160 °C for 30 min). Apart from morphological destructions, FTIR and TGA results indicated different structural changes caused by ozonolysis and SW. Hemicellulose was shown as the major factor hindering enzymatic hydrolysis. Additionally, the soluble polysaccharides generated by these pretreatments were characterized, showing that the single SW pretreatment was better for polysaccharide recovery. These findings may help to maximize the benefits of wheat bran biorefinery.