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Pharmacology Teaching and Research




Cellulose and Cellulase

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Cellulases: Classification, Methods of Determination and Industrial Applications

Microbial cellulases have been receiving worldwide attention, as they have enormous potential to process the most abundant cellulosic biomass on this planet and transform it into sustainable biofuels and other value added products. The synergistic action of endoglucanases, exoglucanases, and β-glucosidases is required for the depolymerization of cellulose to fermentable sugars for transformation in to useful products using suitable microorganisms. The lack of a better understanding of the mechanisms of individual cellulases and their synergistic actions is the major hurdles yet to be overcome for large-scale commercial applications of cellulases. We have reviewed various microbial cellulases with a focus on their classification with mechanistic aspects of cellulase hydrolytic action, insights into novel approaches for determining cellulase activity, and potential industrial applications of cellulases.

Cellulase Inhibition by High Concentrations of Monosaccharides

Biological degradation of biomass on an industrial scale culminates in high concentrations of end products. It is known that the accumulation of glucose and cellobiose, end products of hydrolysis, inhibit cellulases and decrease glucose yields. Aside from these end products, however, other monosaccharides such as mannose and galactose (stereoisomers of glucose) decrease glucose yields as well. NMR relaxometry measurements showed direct correlations between the initial T2 of the liquid phase in which hydrolysis takes place and the total glucose production during cellulose hydrolysis, indicating that low free water availability contributes to cellulase inhibition. Of the hydrolytic enzymes involved, those acting on the cellulose substrate, that is, exo- and endoglucanases, were the most inhibited. The β-glucosidases were shown to be less sensitive to high monosaccharide concentrations except glucose. Protein adsorption studies showed that this inhibition effect was most likely due to catalytic, and not binding, inhibition of the cellulases.

Cellulase Assays

Cellulose is a heterogeneous polysaccharide, and its enzymatic hydrolysis requires endoglucanase, exoglucanase (cellobiohydrolase), and beta-glucosidase to work together. We summarize the most commonly used assays for individual enzymes and cellulase mixture.

Sweet success: Catalyzing more sugars from biomass

Using an ultrahigh-precision microscopy technique, researchers have uncovered a way to improve the collective catalytic activity of enzyme cocktails on cellulosic biomass, boosting the yields of sugars for the production of advanced biofuels.

Switching to renewable energy could save thousands of lives in Africa

Researchers estimate future death toll from fossil fuel emission



β-Glucosidases From the Fungus Trichoderma: An Efficient Cellulase Machinery in Biotechnological Applications

β-glucosidases catalyze the selective cleavage of glucosidic linkages and are an important class of enzymes having significant prospects in industrial biotechnology. These are classified in family 1 and family 3 of glycosyl hydrolase family. β-glucosidases, particularly from the fungus Trichoderma, are widely recognized and used for the saccharification of cellulosic biomass for biofuel production. With the rising trends in energy crisis and depletion of fossil fuels, alternative strategies for renewable energy sources need to be developed. However, the major limitation accounts for low production of β-glucosidases by the hyper secretory strains of Trichoderma. In accordance with the increasing significance of β-glucosidases in commercial applications, the present review provides a detailed insight of the enzyme family, their classification, structural parameters, properties, and studies at the genomics and proteomics levels. Furthermore, the paper discusses the enhancement strategies employed for their utilization in biofuel generation. Therefore, β-glucosidases are prospective toolbox in bioethanol production, and in the near future, it might be successful in meeting the requirements of alternative renewable sources of energy.


New understanding of one of nature’s best biocatalysts for biofuels production

Producing fuels from plants and other renewable sources requires breaking down the chemical cellulose; a major candidate to drive, or catalyze, this stubborn chemical is a ubiquitous microorganism called Clostridium thermocellum that works well in hot environments without oxygen. Researchers found that C. thermocellum uses a previously unknown mechanism to degrade cellulose, in addition to other known degradation mechanisms.


Enzyme's worth to biofuels shown in recent research

A newly discovered enzyme proves adept at breaking down cellulose fibers regardless of whether their crystalline structure is simple or highly complex. No other enzyme has shown that ability.


Microbial cellulases –  Diversity &
biotechnology with reference to mangrove environment: A review

Current Trends in Research and Application of Microbial Cellulases

https://scialert.net/fulltext/?doi=jm.2011.41.53



Microbial cellulases: Production, Application and Challenges

cellulase (4).pdf (146.13KB)
cellulase (4).pdf (146.13KB)

Cellulase Production by Bacteria: A Review

cellulase (1).pdf (482.55KB)
cellulase (1).pdf (482.55KB)



Cellulases: Characteristics, Sources, Production and Applications

Secretory pathway of cellulase: a mini-review