Improved saccharification of pilot-scale acid pretreated wheat straw by exploiting the synergistic behavior of lignocellulose degrading enzymes

Agrawal, Ruchi; Gaur, Ruchi; Mathur, Anshu S.; Kumar, Ravindra; Gupta, Ravi P.; Tuli, Deepak K.; Satlewal, Alok

doi:10.1039/c5ra13360b

Cited by 47 publications

(24 citation statements)

References 36 publications

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“…Dilute acid pre‐treatment (DAP) is one of the most popular pre‐treatment methods because of the low cost of sulfuric acid and ability to perform well on multiple feedstocks. X‐ray diffraction (XRD) analysis showed that the crystallinity Index (CrI) of rice straw increased by about 10% after DAP (Table ) and the possible reason for this apparent increase is the removal of amorphous hemicellulose and lignin and the subsequent enrichment in the concentration of crystalline cellulose . Fourier Transform InfraRed (FTIR) spectroscopy analysis showed that peak intensities for hemicelluloses were either reduced or diminished after DAP but no change in the crystalline cellulose region was observed .…”

Section: Pre‐treatment Of Rice Strawmentioning

confidence: 99%

“…X-ray diff raction (XRD) analysis showed that the crystallinity Index (CrI) of rice straw increased by about 10% aft er DAP (Table 21) and the possible reason for this apparent increase is the removal of amorphous hemicellulose and lignin and the subsequent enrichment in the concentration of crystalline cellulose. 12,119,120 Fourier Transform InfraRed (FTIR) spectroscopy analysis showed that peak intensities for hemicelluloses were either reduced or diminished aft er DAP but no change in the crystalline cellulose region was observed. 74,75,121 Teramura et al 122 , and β-5 (phenylcoumaran) have decreased substantially aft er DAP of rice straw.…”

Section: Pre-treatment Of Rice Strawmentioning

confidence: 99%

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Rice straw as a feedstock for biofuels: Availability, recalcitrance, and chemical properties

Satlewal

Agrawal

Bhagia

et al. 2017

Biofuels Bioprod Bioref

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148

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The surplus availability of rice straw, its limited usage, and environmental pollution caused by its ineffi cient burning has fostered research for its valorization to biofuels. This review elucidates the current status of rice straw potential around the globe along with recent advances in revealing the critical factors responsible for its recalcitrance and chemical properties. The role and accumulation of high silica content in rice straw has been elucidated with its impact on enzymatic hydrolysis in a biorefi nery environment. The correlation of different pre-treatment approaches in modifying the physiochemical properties of rice straw and improving the enzymatic accessibility has also been discussed. This study highlights new challenges, resolutions, and opportunities for rice straw based biorefi neries.

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Section: Pre‐treatment Of Rice Strawmentioning

confidence: 99%

Section: Pre-treatment Of Rice Strawmentioning

confidence: 99%

Rice straw as a feedstock for biofuels: Availability, recalcitrance, and chemical properties

Satlewal

Agrawal

Bhagia

et al. 2017

Biofuels Bioprod Bioref

Self Cite

148

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“…Global energy demand is increasing with an average growth rate of 1.3% per year, and it is expected to increase by 30% by 2035, with the highest energy consumption rate (4.2% per year) in India (Satlewal et al, 2017(Satlewal et al, , 2018a. Bioethanol from lignocellulosic biomass (LB) plays a critical role in meeting this energy demand as a renewable and sustainable source of energy (Agrawal et al, 2015a). One of the primary challenges in producing second-generation biofuels is the recalcitrant nature of the LB, chiefly imposed by the complex lignin-carbohydrate linkages (LCCs).…”

Section: Introductionmentioning

confidence: 99%

Improved Enzymatic Hydrolysis of Pilot Scale Pretreated Rice Straw at High Total Solids Loading

et al. 2018

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Enzymatic hydrolysis at high solids loading has the potential to reduce both capital and operational expenditures. Here, pretreatment of rice straw (PRS) with dilute acid was carried out at a pilot scale (250 kg per day) at 162 • C for 10 min and 0.35% acid concentration, followed by enzymatic hydrolysis at different total solids loadings. It showed that although the total sugar concentration increased from 48 to 132 g/l, glucan conversion reduced by 27% (84-66.2%) with increasing solids from 5 to 20% in batch mode. Therefore, two different fed-batch approaches were evaluated to improve the glucan conversion by the sequential addition of a substrate and/or enzyme. At 20% solid loadings and a 3 filter paper units/g enzyme dosage, the highest glucan conversion obtained was 66% after 30 h of hydrolysis in batch mode. However, in an optimized fed-batch approach, the glucan yield was improved to 70% by simply dividing the substrate feeding into three batches, that is, 50% at 0 h, 25% each after 4 h, and 8 h of hydrolysis reaction. The addition of surfactant (Ecosurf E6) further improved the conversion to 72% after 30 h. The role of critical factors, that is, inhibitors, enzyme-lignin binding, and viscosity, was investigated during the course of hydrolysis in the batch and fed-batch approaches. This study suggests a sustainable approach for improved hydrolysis at high solids loadings by fine-tuning a simple process.

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“…According to Khattak et al ., the utilization of sugars from feed during microbial conversion of cellulose is a crucial drawback. Also, feedback inhibition of cellulases by both intermediate and end products has been widely reported . Nevertheless, it should be observed that Tween 20 was able to maintain the performance and functionality (stability) of the cellulases better than CaCl 2 during EFB saccharification.…”

Section: Resultsmentioning

confidence: 45%

“…Also, feedback inhibition of cellulases by both intermediate and end products has been widely reported. 31,[58][59][60][61] Nevertheless, it should be observed that Tween 20 was able to maintain the performance and functionality (stability) of the cellulases better than CaCl 2 during EFB saccharification.…”

Section: Efb Saccharification Using the Optimized Enzyme Blend Ratiomentioning

confidence: 99%

An optimal blend of single autodisplayed cellulases for cellulose saccharification – a proof of concept

Obeng

Ongkudon

Budiman

et al. 2018

J of Chemical Tech & Biotech

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BACKGOUND To date, it has been challenging to determine the optimal proportions of the individual cellulases in crude extracts and multienzyme systems to promote enzyme synergism. The application of single surface‐display of enzymes may obviate such challenges. This article presents a proof of concept of the optimal mixing of single surface‐displayed cellulases for cellulose hydrolysis using Simplex lattice mixture design. RESULTS The recently discovered maximized autotransporter‐mediated expression system was used to express the three cellulases. The biochemical screening analysis revealed that the enzymes have a broad range of functional pH (4–9) and temperature (30–100 °C) characteristics. The evaluated optima were pH 6 and 60 °C. Through the statistical design of experiment, a blend ratio of 1: 1.6: 1.4 of endoglucanase: exoglucanase: β‐glucosidase was identified as the ‘sweet spot’ for optimum sugar yield. The application of this blend generated about 0.354 mg mL‐1 and 0.446 mg mL‐1 of sugars from filter paper (Ø 6 mm, ∼2.5 mg) and 2.5% pretreated EFB, respectively, within 12 h. Supplementing the enzyme blend with CaCl2 and Tween 20 improved the sugar yield. CONCLUSION This research has revealed an interesting concept of efficiently addressing cellulase synergism. The overall outcome of this research is promising for the derivation of value from lignocellulose. © 2018 Society of Chemical Industry

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Improved saccharification of pilot-scale acid pretreated wheat straw by exploiting the synergistic behavior of lignocellulose degrading enzymes

Cited by 47 publications

References 36 publications

Rice straw as a feedstock for biofuels: Availability, recalcitrance, and chemical properties

Rice straw as a feedstock for biofuels: Availability, recalcitrance, and chemical properties

Improved Enzymatic Hydrolysis of Pilot Scale Pretreated Rice Straw at High Total Solids Loading

An optimal blend of single autodisplayed cellulases for cellulose saccharification – a proof of concept

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