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Characterization of two acidic β-glucosidases and ethanol fermentation in the brown rot fungus Fomitopsis palustris

Paper ID Volume ID Publish Year Pages File Format Full-Text
17500 42673 2011 6 PDF Available
Title
Characterization of two acidic β-glucosidases and ethanol fermentation in the brown rot fungus Fomitopsis palustris
Abstract

Two acidic β-glucosidases (βGI and βGII) from the brown rot fungus Fomitopsis palustris were purified to homogeneity by several chromatographic steps. βGI and βGII had molecular weights of 130 and 213 kDa, respectively, and exhibited optimum activity at pH 2.5 and 55 °C. The Km values of βGI and βGII for p-nitrophenyl-β-d-glucopyranoside were 0.706 and 0.971 mM, respectively. Although the effect of metal ions and inhibitors differed between the two enzymes, both β-glucosidases exhibited preferential glucose release during hydrolysis of cello-oligosaccharides, indicating that βGI and βGII possess effective exo-type activities. Notably, F. palustris was able to produce ethanol when cultured on medium containing 20 g/l of glucose, mannose, cellobiose, and maltose, in which the maximum ethanol concentrations measured were 9.2, 8.7, 9.0, and 8.9 g/l, corresponding to 90.2%, 85.3%, 88.2%, and 87.3% of the theoretical yield, respectively. These findings suggest that F. palustris has the ability not only to secrete β-glucosidase enzymes effective at low pH, but also to function as a biocatalyst, which may be suitable for the conversion of lignocellulosic materials into ethanol.

Keywords
β-Glucosidase; Purification; Ethanol; Fermentation; Brown rot fungus; Fomitopsis palustris
First Page Preview
Characterization of two acidic β-glucosidases and ethanol fermentation in the brown rot fungus Fomitopsis palustris
Publisher
Database: Elsevier - ScienceDirect
Journal: Enzyme and Microbial Technology - Volume 48, Issues 4–5, 7 April 2011, Pages 359–364
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering