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Characterization and comparison of thermostability of purified β-glucosidases from a mesophilic Aureobasidium pullulans and a thermophilic Thermoascus aurantiacus

Paper ID Volume ID Publish Year Pages File Format Full-Text
35865 45111 2007 6 PDF Available
Title
Characterization and comparison of thermostability of purified β-glucosidases from a mesophilic Aureobasidium pullulans and a thermophilic Thermoascus aurantiacus
Abstract

The thermophilic fungus Thermoascus aurantiacus 179-5 and the mesophilic Aureobasidium pullulans ER-16 were cultivated in corn-cob by solid state fermentation for β-glucosidase production. After fermentation both enzymes were purified. The β-glucosidases produced by the strains A. pullulans and T. aurantiacus were most active at pH 4.0–4.5 and 4.5, with apparent optimum temperatures at 80 and 75 °C, respectively. Surprisingly, the enzyme produced by the mesophilic A. pullulans was stable over a wider range of pH (4.5–9.5 against 4.5–6.5) and more thermostable (98% after 1 h at 75 °C against 98% after 1 h at 70 °C) than the enzyme from the thermophilic T. aurantiacus. The t(1/2) at 80 °C were 90 and 30 min for A. pullulans and T. aurantiacus, respectively. β-Glucosidase thermoinactivation followed first-order kinetics and the energies of denaturation were 414 and 537 kJ mol−1 for T. aurantiacus and A. pullulans, respectively. The result showed that β-glucosidase obtained from the mesophilic A. pullulans is more stable than that obtained from the thermophilic T. aurantiacus.

Keywords
β-Glucosidase; Aureobasidium pullulans; Thermoascus aurantiacus; Thermoinactivation; Thermostability; Thermophilic
First Page Preview
Characterization and comparison of thermostability of purified β-glucosidases from a mesophilic Aureobasidium pullulans and a thermophilic Thermoascus aurantiacus
Publisher
Database: Elsevier - ScienceDirect
Journal: Process Biochemistry - Volume 42, Issue 7, July 2007, Pages 1101–1106
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering