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Characterization of a glucose-tolerant β-glucosidase from Anoxybacillus sp. DT3-1

Chan, C. S. and Sin, L. L. and Chan, K. G. and Shamsir, M. S. and Manan, F. A. and Sani, R. K. and Goh, K. M. (2016) Characterization of a glucose-tolerant β-glucosidase from Anoxybacillus sp. DT3-1. Biotechnology for Biofuels, 9 (1). ISSN 1754-6834

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Abstract

Background: In general, biofuel production involves biomass pretreatment and enzymatic saccharification, followed by the subsequent sugar conversion to biofuel via fermentation. The crucial step in the production of biofuel from biomass is the enzymatic saccharification. Many of the commercial cellulase enzyme cocktails, such as Spezyme® CP (Genencor), Acellerase™ 1000 (Genencor), and Celluclast® 1.5L (Novozymes), are ineffectively to release free glucose from the pretreated biomass without additional β-glucosidase. Results: In this study, for the first time, a β-glucosidase DT-Bgl gene (1359 bp) was identified in the genome of Anoxybacillus sp. DT3-1, and cloned and heterologously expressed in Escherichia coli BL21. Phylogenetic analysis indicated that DT-Bgl belonged to glycosyl hydrolase (GH) family 1. The recombinant DT-Bgl was highly active on cello-oligosaccharides and p-nitrophenyl-β-d-glucopyranoside (pNPG). The DT-Bgl was purified using an Ni-NTA column, with molecular mass of 53 kDa using an SDS-PAGE analysis. It exhibited optimum activity at 70 °C and pH 8.5, and did not require any tested co-factors for activation. The K m and V max values for DT-Bgl were 0.22 mM and 923.7 U/mg, respectively, with pNPG as substrate. The DT-Bgl displayed high glucose tolerance, and retained 93 % activity in the presence of 10 M glucose. Conclusions: Anoxybacillus DT-Bgl is a novel thermostable β-glucosidase with low glucose inhibition, and converts long-chain cellodextrins to cellobiose, and further hydrolyse cellobiose to glucose. Results suggest that DT-Bgl could be useful in the development of a bioprocess for the efficient saccharification of lignocellulosic biomass.

Item Type:Article
Uncontrolled Keywords:Bioconversion, Biofuels, Biomass, Cloning, Escherichia coli, Hydrolases, Saccharification, Anoxybacillus, Biomass conversion, Biomass pre treatments, Cello-oligosaccharides, Enzymatic saccharification, Glucose tolerance, Glycosyl hydrolases, Lignocellulosic biomass, Glucose, biofuel, biomass, coliform bacterium, gene, genome, glucose, tolerance, Anoxybacillus, Escherichia coli
Subjects:Q Science > QH Natural history
Divisions:Biosciences and Medical Engineering
ID Code:72190
Deposited By: Fazli Masari
Deposited On:23 Nov 2017 14:19
Last Modified:23 Nov 2017 14:19

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