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Characterization of a novel thermostable β-glucosidase from a metagenomic library of termite gut

Paper ID Volume ID Publish Year Pages File Format Full-Text
17184 42650 2012 6 PDF Available
Title
Characterization of a novel thermostable β-glucosidase from a metagenomic library of termite gut
Abstract

A novel β-glucosidase-encoding gene, bgl-gs1, which was identified from a positive fosmid clone in a metagenomic library of the gut of Globitermes sulphureus, encodes a 455 amino acid polypeptide that contains a catalytic domain belonging to glycoside hydrolase family 1 (GH1). It was expressed in Escherichia coli BL21 (DE3) and the expression product showed a molecular mass of ∼51.7 kDa by SDS-PAGE. The optimal temperature and pH for the activity of the purified recombinant enzyme Bgl-gs1 with p-nitrophenyl-β-d-glucoside (pNPG) were 90 °C and 6.0, respectively. The specific activities of Bgl-gs1 on pNPG and salicin were 110 and 14 U/mg of protein, respectively, and its Km values were 0.18 and 2.59 mM, respectively. The residual activity of Bgl-gs1 was maintained above 70% after the recombinant enzyme was incubated at 75 °C and pH 6.0 for 2 h, and its half-life at 90 °C was approximately 1 h in the presence of 4 mM pNPG. Bgl-gs1 showed synergistic effect with either a crude enzyme mixture of the fungal strain Trichoderma reesei Rut-C30 or a fusion protein (TcE1) created from the cellobiohydrolase cbh1 gene of T. reesei and endoglucanase from Acidothermus cellulolyticus; 87 and 137% increases in hydrolytic efficiency were noted on microcrystalline cellulose, respectively. These results suggest that the thermostable β-glucosidase Bgl-gs1 is a likely candidate for industrial applications.

► A novel β-glucosidase gene, bgl-gs1, was identified from metagenomic library. ► It is demonstrated a higher optimal temperature than other GH1 BGL. ► It showed a strong synergistic effect with crude cellulase secreted by T. reesei. ► Bgl-gs1 has great potential for industrial applications and basic research.

Keywords
Metagenomic; Globitermes sulphureus gut; β-Glucosidase; Thermostable; Synergistic effect
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Characterization of a novel thermostable β-glucosidase from a metagenomic library of termite gut
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Publisher
Database: Elsevier - ScienceDirect
Journal: Enzyme and Microbial Technology - Volume 51, Issues 6–7, 10 December 2012, Pages 319–324
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us