Simultaneous Biological Pretreatment and Saccharification of Rice Straw by Ligninolytic Enzymes from Panus neostrigosus I9 and Commercial Cellulase

The utilization of rice straw for biofuel production is limited by its composition. The pretreatment process is required to improve the enzymatic accessibility of polysaccharides in the biomass prior to enzymatic saccharification. In this study, simultaneous biological pretreatment and saccharification (SPS) of rice straw starting from laccase production by Panus neostrigosus I9 was operated in a 2-L fermenter. It was found that fungal physiology was strongly influenced by the agitation, and that the highest laccase production was obtained at an agitation speed of 750 rpm (209.96 ± 0.34 U/L). The dilution rate of 0.05 h−1 was set in continuous fermentation which resulted in laccase activity of 678.49 ± 20.39 U/L, approximately three times higher than that in batch culture. Response surface methodology (RSM) was applied to achieve the condition for maximum percentage of delignification. The maximum percentage of delignification of 45.55% was accomplished after pretreatment of rice straw with laccase enzyme 39.40 U/g rice straw at 43.70 °C for 11.19 h. Reducing sugar of 3.85 ± 0.15 g/L was obtained from the digested rice straw in a SPS reactor, while non-pretreated rice straw gave only 1.13 ± 0.10 g/L within 12 h of incubation. The results indicated that simultaneous biological pretreatment and saccharification (SPS) of rice straw by laccase helped to improve the accessibility of cellulose by cellulolytic enzymes.

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Biological pretreatment of rice straw with Streptomyces griseorubens JSD-1 and its optimized production of cellulase and xylanase for improved enzymatic saccharification efficiency

Preparative Biochemistry & Biotechnology ◽

10.1080/10826068.2015.1084932 ◽

2016 ◽

Vol 46 (6) ◽

pp. 575-585 ◽

Cited By ~ 8

Author(s):

Dan Zhang ◽

Yanqing Luo ◽

Shaohua Chu ◽

Yuee Zhi ◽

Bin Wang ◽

...

Keyword(s):

Rice Straw ◽

Enzymatic Saccharification ◽

Biological Pretreatment ◽

Streptomyces Griseorubens ◽

Saccharification Efficiency

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Biological Pretreatment of Corn Stover for Enhancing Enzymatic Hydrolysis Using Thermoalkalotolerant Cellulolytic Enzymes Produced by Bacillus sp. P3

10.21203/rs.3.rs-665509/v1 ◽

2021 ◽

Author(s):

Yanwen Wu ◽

Haipeng Guo ◽

Md. Shafiqur Rahman ◽

Xuantong Chen ◽

Jinchi Zhang ◽

...

Keyword(s):

Enzymatic Hydrolysis ◽

Corn Stover ◽

Fermentation Broth ◽

Removal Rate ◽

Enzymatic Saccharification ◽

Cellulolytic Enzymes ◽

Biological Pretreatment ◽

Hydrolysis Process ◽

Hemicellulose Removal ◽

Hydrolysis Of

Abstract The biological pretreatment for the enzymatic hydrolysis of lignocellulosic biomasses largely depends on an effective pretreatment process. A significant enhancement of enzymatic saccharification was obtained with corn stover using Bacillus sp. P3. The hemicellulose removal from corn stover by the strain Bacillus sp. P3 was evaluated for enhancing subsequent enzymatic hydrolysis. Therefore, our study revealed that an alkaline resistant xylanase produced by Bacillus sp. P3 in fermentation broth led to a substantially enhanced hemicellulose removal rate from corn stover within pH 9.36–9.68. However, after 20 d pretreatment of corn stover by the strain P3, the glucan content was increased by 51% and the xylan content was decreased by 35%. After 72 h of saccharification using 20 U g− 1 of commercial cellulase, the yield of reducing sugar released from 20 d pretreated corn stover was increased by 56% in comparison to the untreated corn stover. Therefore, the use of the strain P3 could be a promising approach to pretreat corn stover for enhancing the enzymatic hydrolysis process of industrial bioenergy productions.

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Generation of highly amenable cellulose-Iβ via selective delignification of rice straw using a reusable cyclic ether-assisted deep eutectic solvent system

Scientific Reports ◽

10.1038/s41598-020-80719-x ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Chiranjeevi Thulluri ◽

Ravi Balasubramaniam ◽

Harshad Ravindra Velankar

Keyword(s):

Enzymatic Hydrolysis ◽

Rice Straw ◽

Deep Eutectic Solvent ◽

Solvent System ◽

Cyclic Ether ◽

Cellulolytic Enzymes ◽

Ammonium Bromide ◽

Selective Delignification ◽

Cellulose Iβ ◽

Hydrolysis Of

AbstractCellulolytic enzymes can readily access the cellulosic component of lignocellulosic biomass after the removal of lignin during biomass pretreatment. The enzymatic hydrolysis of cellulose is necessary for generating monomeric sugars, which are then fermented into ethanol. In our study, a combination of a deep eutectic (DE) mixture (of 2-aminoethanol and tetra-n-butyl ammonium bromide) and a cyclic ether (tetrahydrofuran) was used for selective delignification of rice straw (RS) under mild conditions (100 °C). Pretreatment with DE-THF solvent system caused ~ 46% delignification whereas cellulose (~ 91%) and hemicellulose (~ 67%) recoveries remained higher. The new solvent system could be reused upto 10 subsequent cycles with the same effectivity. Interestingly, the DE-THF pretreated cellulose showed remarkable enzymatic hydrolysability, despite an increase in its crystallinity to 72.3%. Contrary to conventional pretreatments, we report for the first time that the enzymatic hydrolysis of pretreated cellulose is enhanced by the removal of lignin during DE-THF pretreatment, notwithstanding an increase in its crystallinity. The current study paves way for the development of newer strategies for biomass depolymerization with DES based solvents.

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Diverse Banana Pseudostems and Rachis Are Distinctive for Edible Carbohydrates and Lignocellulose Saccharification towards High Bioethanol Production under Chemical and Liquid Hot Water Pretreatments

Molecules ◽

10.3390/molecules26133870 ◽

2021 ◽

Vol 26 (13) ◽

pp. 3870

Author(s):

Jingyang Li ◽

Fei Liu ◽

Hua Yu ◽

Yuqi Li ◽

Shiguang Zhou ◽

...

Keyword(s):

Soluble Sugars ◽

Enzymatic Saccharification ◽

Hot Water ◽

Biofuel Production ◽

Bioenergy Crops ◽

Bioethanol Production ◽

Factors Affecting ◽

Liquid Hot Water ◽

Biomass Processing ◽

Banana Crops

Banana is a major fruit crop throughout the world with abundant lignocellulose in the pseudostem and rachis residues for biofuel production. In this study, we collected a total of 11 pseudostems and rachis samples that were originally derived from different genetic types and ecological locations of banana crops and then examined largely varied edible carbohydrates (soluble sugars, starch) and lignocellulose compositions. By performing chemical (H2SO4, NaOH) and liquid hot water (LHW) pretreatments, we also found a remarkable variation in biomass enzymatic saccharification and bioethanol production among all banana samples examined. Consequently, this study identified a desirable banana (Refen1, subgroup Pisang Awak) crop containing large amounts of edible carbohydrates and completely digestible lignocellulose, which could be combined to achieve the highest bioethanol yields of 31–38% (% dry matter), compared with previously reported ones in other bioenergy crops. Chemical analysis further indicated that the cellulose CrI and lignin G-monomer should be two major recalcitrant factors affecting biomass enzymatic saccharification in banana pseudostems and rachis. Therefore, this study not only examined rich edible carbohydrates for food in the banana pseudostems but also detected digestible lignocellulose for bioethanol production in rachis tissue, providing a strategy applicable for genetic breeding and biomass processing in banana crops.

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Bioreactor and Bioprocess Design Issues in Enzymatic Hydrolysis of Lignocellulosic Biomass

Catalysts ◽

10.3390/catal11060680 ◽

2021 ◽

Vol 11 (6) ◽

pp. 680

Author(s):

Giuseppe Olivieri ◽

René H. Wijffels ◽

Antonio Marzocchella ◽

Maria Elena Russo

Keyword(s):

Lignocellulosic Biomass ◽

Enzymatic Saccharification ◽

Product Inhibition ◽

Cellulolytic Enzymes ◽

Main Process ◽

Bioprocess Design ◽

Operating Modes ◽

Biomass Saccharification ◽

Starting Point ◽

The Impact

Saccharification of lignocellulosic biomass is a fundamental step in the biorefinery of second generation feedstock. The physicochemical and enzymatic processes for the depolymerization of biomass into simple sugars has been achieved through numerous studies in several disciplines. The present review discusses the development of technologies for enzymatic saccharification in industrial processes. The kinetics of cellulolytic enzymes involved in polysaccharide hydrolysis has been discussed as the starting point for the design of the most promising bioreactor configurations. The main process configurations—proposed so far—for biomass saccharification have been analyzed. Attention was paid to bioreactor configurations, operating modes and possible integrations of this operation within the biorefinery. The focus is on minimizing the effects of product inhibition on enzymes, maximizing yields and concentration of sugars in the hydrolysate, and reducing the impact of enzyme cost on the whole process. The last part of the review is focused on an emerging process based on the catalytic action of laccase applied to lignin depolymerization as an alternative to the consolidated physicochemical pretreatments. The laccases-based oxidative process has been discussed in terms of characteristics that can affect the development of a bioreactor unit where laccases or a laccase-mediator system can be used for biomass delignification.

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Production of Highly Thermostable Laccase from Penicillium spinulosum for Enhanced Delignification of Untreated Wheat Bran

Current Biotechnology ◽

10.2174/2211550110666210720123414 ◽

2021 ◽

Vol 10 ◽

Author(s):

Folasade M. Olajuyigbe ◽

Ademola K. Oduwole ◽

Cornelius O. Fatokun

Keyword(s):

Physicochemical Properties ◽

Wheat Bran ◽

Plant Cell Wall ◽

Palm Kernel ◽

Residual Activity ◽

Thermostable Enzyme ◽

Biofuel Production ◽

Laccase Production ◽

Trichoderma Species ◽

High Thermostability

Background: Lignin confers rigidity on plant cell wall and poses a challenge to hydrolysis of cellulose, which makes production of biofuels from lignocellulose an overwhelming problem. This prompts continuous search for novel ligninolytic enzymes, especially, laccases for delignification of lignocellulose for improved saccharification of biomass. Objective: This study reports production, physicochemical properties and delignification efficiency of laccases from Penicillium and Trichoderma species on untreated wheat bran. Methods: Fungal laccases were produced using different agroresidues (wheat bran, coconut shell and palm kernel shell) as substrates in submerged fermentation. Best substrate for laccase production was determined. Physicochemical properties of crude enzymes and delignification efficiency of the laccases were determined on untreated wheat bran using pure laccase as control. Results: Wheat bran supported maximum laccase production from fungi under study. Highest laccase yield of 22.5 U/mL was obtained from P. spinulosum. Laccase from P. spinulosum was optimally active at pH 7.0 and 50 °C and exhibited remarkable high thermostability with 61.6% residual activity at 90 °C after 2 h incubation. The activity of the thermostable enzyme was enhanced in the presence of Cu2+. Biodelignification efficiency of cell-free extract from P. spinulosum, T. koningii, and P. restrictum on wheat bran were 95%, 81.5% and 63.5%, respectively. Surprisingly, a much lower delignification efficiency of 33.42% was obtained with commercial laccase from Trametes versicolor. Conclusion: The high thermostability and striking delignification efficiency of laccase from P. spinulosum make the enzyme a good bioresource for biodelignification of untreated lignocellulose for biofuel production.

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A semi-dominant mutation in OsCESA9 improves biomass enzymatic digestibility and salt tolerance by relatively remodeling cell walls in rice

10.21203/rs.3.rs-63488/v2 ◽

2020 ◽

Author(s):

Yafeng Ye ◽

Shuoxun Wang ◽

Kun Wu ◽

Yan Ren ◽

Hongrui Jiang ◽

...

Keyword(s):

Salt Tolerance ◽

Plant Growth ◽

Rice Straw ◽

Enzymatic Saccharification ◽

Cellulose Content ◽

Normal Plant ◽

Wild Type ◽

Negative Effects ◽

Straw Return ◽

Almost All

Abstract Background: Cellulose synthase (CESA) mutants have potential use in straw processing due to their lower cellulose content, but almost all of the mutants exhibit defective phenotypes in plant growth and development. Balancing normal plant growth with reduced cellulose content remains a challenge, as cellulose content and normal plant growth are typically negatively correlated with one another. Result: Here, the rice (Oryza sativa) semi-dominant brittle culm (sdbc) mutant Sdbc1, which harbors a substitution (D387N) at the first conserved aspartic acid residue of OsCESA9, exhibits lower cellulose content and reduced secondary wall thickness as well as enhanced biomass enzymatic saccharification compared with the wild type (WT). Further experiments indicated that the OsCESA9D387N mutation may compete with the wild-type OsCESA9 for interacting with OsCESA4 and OsCESA7, further forming non-functional or partially functional CSCs. The OsCESA9/OsCESA9D387N heterozygous plants increase salt tolerance through scavenging and detoxification of ROS and indirectly affecting related gene expression. They also improve rice straw return to the field due to their brittle culms and lower cellulose content without any negative effects in grain yield and lodging. Conclusion: Hence, manipulation of OsCESA9D387N can provide the perspective of the rice straw for biofuels and bioproducts due to its improved enzymatic saccharification.

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Control of pH by CO2 Pressurization for Enzymatic Saccharification of Ca(OH)2-Pretreated Rice Straw in the Presence of CaCO3

Journal of Applied Glycoscience ◽

10.5458/jag.jag.jag-2019_0019 ◽

2020 ◽

Vol 67 (2) ◽

pp. 59-62

Author(s):

Masakazu Ike ◽

Ken Tokuyasu

Keyword(s):

Rice Straw ◽

Enzymatic Saccharification

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Expression of serpins by Clostridium thermocellum and simultaneous saccharification of lignocellulosic biomass to enhance ethanol production

BioResources ◽

10.15376/biores.15.4.8662-8676 ◽

2020 ◽

Vol 15 (4) ◽

pp. 8662-8676

Author(s):

Maria Mushtaq ◽

Muhammad Javaid Asad ◽

Muhammad Zeeshan Hyder ◽

Syed Muhammad Saqlan Naqvi ◽

Saad Imran Malik ◽

...

Keyword(s):

Ethanol Production ◽

Wheat Straw ◽

Corn Stover ◽

Rice Straw ◽

Clostridium Thermocellum ◽

Ethanol Yield ◽

Biofuel Production ◽

Yeast Fermentation ◽

Second Generation Bioethanol ◽

Simultaneous Saccharification

Utilization of biomass for production of second generation bioethanol was considered as a way to reduce burdens of fossil fuel in Pakistan. The materials wheat straw, rice straw, cotton stalk, corn stover, and peel wastes were used in this experiment. Various parameters, such as acidic and alkali pretreatment, enzymatic hydrolysis by cellulases, and effect of proteases inhibitors on ethanol production, were examined. Fermentation was completed by the yeasts Saccharomyces cerevisiae and Clostridium thermocellum separately, and their ethanol production were compared and maximum ethanol yield was obtained with wheat straw i.e.,11.3 g/L by S. cerevisiae and 8.5 g/L by C. thermocellum. Results indicated that a higher quantity of sugar was obtained from wheat straw (19.6 ± 1.6 g/L) followed by rice straw (17.6 ± 0.6 g/L) and corn stover (16.1 ± 0.9 g/L) compared to the other evaluated biomass samples. A higher yield of ethanol (11.3 g/L) was observed when a glucose concentration of 21.7 g/L was used, for which yeast fermentation efficiency was 92%. Results also revealed the increased in ethanol production (93%) by using celluases in combination with recombinant Serine protease inhibitors from C. thermocellum. It is expected that the use of recombinant serpins with cellulases will play a major role in the biofuel production by using agricultural biomass. This will also help in the economics of the biofuel.

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