Enhancing Lignocellulosic Biomass Hydrolysis by Hydrothermal Pretreatment, Extraction of Surface Lignin, Wet Milling and Production of Cellulolytic Enzymes

ChemSusChem ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1179-1195 ◽  
Author(s):  
Christos K. Nitsos ◽  
Polykarpos A. Lazaridis ◽  
Astrid Mach‐Aigner ◽  
Kostas A. Matis ◽  
Konstantinos S. Triantafyllidis
Keyword(s):  
Lignocellulosic Biomass ◽  
Hydrothermal Pretreatment ◽  
Cellulolytic Enzymes ◽  
Wet Milling ◽  
Biomass Hydrolysis

scholarly journals Engineering of Saccharomyces cerevisiae for efficient fermentation of cellulose

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Eun Joong Oh ◽  
Yong-Su Jin
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Lignocellulosic Biomass ◽  
Biofuel Production ◽  
Cellulolytic Enzymes ◽  
Microbial Conversion ◽  
Biomass Hydrolysis ◽  
Yeast Strains ◽  
Attractive Option ◽  
Engineered Yeast ◽  
Efficient Fermentation

ABSTRACT Conversion of lignocellulosic biomass to biofuels using microbial fermentation is an attractive option to substitute petroleum-based production economically and sustainably. The substantial efforts to design yeast strains for biomass hydrolysis have led to industrially applicable biological routes. Saccharomyces cerevisiae is a robust microbial platform widely used in biofuel production, based on its amenability to systems and synthetic biology tools. The critical challenges for the efficient microbial conversion of lignocellulosic biomass by engineered S. cerevisiae include heterologous expression of cellulolytic enzymes, co-fermentation of hexose and pentose sugars, and robustness against various stresses. Scientists developed many engineering strategies for cellulolytic S. cerevisiae strains, bringing the application of consolidated bioprocess at an industrial scale. Recent advances in the development and implementation of engineered yeast strains capable of assimilating lignocellulose will be reviewed.

KINETIC AND ENZYME RECYCLING STUDIES OF IMMOBILIZED b-GLUCOSIDASE FOR LIGNOCELLULOSIC BIOMASS HYDROLYSIS

2018 ◽  
Vol 17 (6) ◽  
pp. 1385-1398 ◽  
Author(s):  
Deepak K. Tuli ◽  
Ruchi Agrawal ◽  
Alok Satlewal ◽  
Anshu S. Mathur ◽  
Ravi P. Gupta ◽  
...  
Keyword(s):  
Lignocellulosic Biomass ◽  
Biomass Hydrolysis ◽  
Enzyme Recycling

Optimization of Hydrothermal Pretreatment of Lignocellulosic Biomass in the Bioethanol Production Process

ChemSusChem ◽  
2012 ◽  
Vol 6 (1) ◽  
pp. 110-122 ◽  
Author(s):  
Christos K. Nitsos ◽  
Konstantinos A. Matis ◽  
Kostas S. Triantafyllidis
Keyword(s):  
Production Process ◽  
Lignocellulosic Biomass ◽  
Hydrothermal Pretreatment ◽  
Bioethanol Production

scholarly journals Co-culture of Vel1-overexpressed Trichoderma asperellum and Bacillus amyloliquefaciens: An eco-friendly strategy to hydrolyze the lignocellulose biomass in soil to enrich the soil fertility, plant growth and disease resistance

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Valliappan Karuppiah ◽  
Lu Zhixiang ◽  
Hongyi Liu ◽  
Murugappan Vallikkannu ◽  
Jie Chen
Keyword(s):  
Disease Resistance ◽  
Plant Growth ◽  
Corn Stover ◽  
Bacillus Amyloliquefaciens ◽  
Genetically Engineered ◽  
Cellulolytic Enzymes ◽  
Regulation Of Transcription ◽  
Trichoderma Asperellum ◽  
Biomass Hydrolysis ◽  
Lignocellulose Biodegradation

Abstract Background Retention of agricultural bio-mass residues without proper treatment could affect the subsequent plant growth. In the present investigation, the co-cultivation of genetically engineered T. asperellum and B. amyloliquefaciens has been employed for multiple benefits including the enrichment of lignocellulose biodegradation, plant growth, defense potential and disease resistance. Results The Vel1 gene predominantly regulates the secondary metabolites, sexual and asexual development as well as cellulases and polysaccharide hydrolases productions. Overexpression mutant of the Trichoderma asperellum Vel1 locus (TA OE-Vel1) enhanced the activity of FPAase, CMCase, PNPCase, PNPGase, xylanase I, and xylanase II through the regulation of transcription regulating factors and the activation of cellulase and xylanase encoding genes. Further, these genes were induced upon co-cultivation with Bacillus amyloliquefaciens (BA). The co-culture of TA OE-Vel1 + BA produced the best composition of enzymes and the highest biomass hydrolysis yield of 89.56 ± 0.61%. The co-culture of TA OE-Vel1 + BA increased the corn stover degradation by the secretion of cellulolytic enzymes and maintained the C/N ratio of the corn stover amended soil. Moreover, the TA OE-Vel1 + BA increased the maize plant growth, expression of defense gene and disease resistance against Fusarium verticillioides and Cohilohorus herostrophus. Conclusion The co-cultivation of genetically engineered T. asperellum and B. amyloliquefaciens could be utilized as a profound and meaningful technique for the retention of agro residues and subsequent plant growth.

scholarly journals Bioreactor and Bioprocess Design Issues in Enzymatic Hydrolysis of Lignocellulosic Biomass

Catalysts ◽  
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.

scholarly journals Supercharged Cellulases Show Reduced Non-Productive Binding, But Enhanced Activity, on Pretreated Lignocellulosic Biomass

2021 ◽  
Author(s):  
Bhargava Nemmaru ◽  
Jenna Douglass ◽  
John M Yarbrough ◽  
Antonio De Chellis ◽  
Srivatsan Shankar ◽  
...  
Keyword(s):  
Cell Wall ◽  
Corn Stover ◽  
Lignocellulosic Biomass ◽  
Hydrolytic Activity ◽  
Fine Tuning ◽  
Cellulolytic Enzymes ◽  
Crystalline Cellulose ◽  
Cell Wall Components ◽  
Carbohydrate Binding Modules ◽  
Wall Components

Non-productive adsorption of cellulolytic enzymes to various plant cell wall components, such as lignin and cellulose, necessitates high enzyme loadings to achieve efficient conversion of pretreated lignocellulosic biomass to fermentable sugars. Carbohydrate-binding modules (CBMs), appended to various catalytic domains (CDs), promote lignocellulose deconstruction by increasing targeted substrate-bound CD concentration but often at the cost of increased non-productive enzyme binding. Here, we demonstrate how a computational protein design strategy can be applied to a model endocellulase enzyme (Cel5A) from Thermobifida fusca to allow fine-tuning its CBM surface charge, which led to increased hydrolytic activity towards pretreated lignocellulosic biomass (e.g., corn stover) by up to ~330% versus the wild-type Cel5A control. We established that the mechanistic basis for this improvement arises from reduced non-productive binding of supercharged Cel5A mutants to cell wall components such as crystalline cellulose (up to 1.7-fold) and lignin (up to 1.8-fold). Interestingly, supercharged Cel5A mutants that showed improved activity on various forms of pretreated corn stover showed increased reversible binding to lignin (up to 2.2-fold) while showing no change in overall thermal stability remarkably. In general, negative supercharging led to increase hydrolytic activity towards both pretreated lignocellulosic biomass and crystalline cellulose whereas positive supercharging led to a reduction of hydrolytic activity. Overall, selective supercharging of protein surfaces was shown to be an effective strategy for improving hydrolytic performance of cellulolytic enzymes for saccharification of real-world pretreated lignocellulosic biomass substrates. Future work should address the implications of supercharging cellulases from various families on inter-enzyme interactions and synergism.

scholarly journals A novel high performance metagenome-derived alkali-thermostable endo-β-1,4-glucanase for lignocellulosic biomass hydrolysis in the harsh conditions

2020 ◽  
Author(s):  
Shohreh Ariaeenejad ◽  
Atefeh Sheykhabdolahzadeh ◽  
Morteza Maleki ◽  
Kaveh Kavousi ◽  
Mehdi Foroozandeh Shahraki ◽  
...  
Keyword(s):  
Enzymatic Hydrolysis ◽  
Lignocellulosic Biomass ◽  
Rice Straw ◽  
Specific Activity ◽  
Agricultural Waste ◽  
Extreme Temperature ◽  
In Silico Analysis ◽  
Cellulose Content ◽  
Biomass Hydrolysis ◽  
Harsh Condition

Abstract Background: Lignocellulosic biomass, is a great resource for the production of bio-energy and bio-based material since it is largely abundant, inexpensive and renewable. The requirement of new energy sources has led to a wide search for novel effective enzymes to improve the exploitation of lignocellulose, among which the importance of thermostable and halotolerant cellulase enzymes with high pH performance is significant. Results: The primary aim of this study was to discover a novel alkali-thermostable endo-β-1,4-glucanase from the sheep rumen metagenome. Using a multi-step in-silico analysis, primary candidates with desired properties were found and subjected to cloning, expression, and purification followed by functional and structural characterization. The enzymes' kinetic parameters, including V max , Km, and specific activity, were calculated. The PersiCel4 demonstrated its optimum activity at pH 8.5 and a temperature of 85°C and was able to retain more than 70% of its activity after 150 hours of storage at 85°C. Furthermore, this enzyme was able to maintain its catalytic activity in the presence of different concentrations of NaCl, MgCl 2 , CaCl 2 , and MnCl 2 . Our results showed that treatment with MnCl 2 could enhance the enzyme’s activity by 89%. PersiCel4 was ultimately used for enzymatic hydrolysis of autoclave pretreated rice straw, the most abundant agricultural waste with rich cellulose content. In autoclave treated rice straw, enzymatic hydrolysis with the PersiCel4 increased the release of reducing sugar up to 260% after 72 hours in the harsh condition ( T= 85°C, pH = 8.5). Conclusion: Considering the urgent demand for stable cellulases that are operational on extreme temperature and pH conditions and due to several proposed distinctive characteristics of PersiCel4, it can be used in the harsh condition for bioconversion of lignocellulosic biomass.

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