title: Production and Characterization of Highly Thermostable β-Glucosidase during the Biodegradation of Methyl Cellulose by Fusarium oxysporum.
abstract: Production of β-glucosidase from Fusarium oxysporum was investigated during degradation of some cellulosic substrates (Avicel, α-cellulose, carboxymethyl cellulose (CMC), and methylcellulose). Optimized production of β-glucosidase using the cellulosic substrate that supported highest yield of enzyme was examined over 192 h fermentation period and varied pH of 3.0-11.0. The β-glucosidase produced was characterized for its suitability for industrial application. Methyl cellulose supported the highest yield of β-glucosidase (177.5 U/mg) at pH 6.0 and 30°C at 96 h of fermentation with liberation of 2.121 μmol/mL glucose. The crude enzyme had optimum activity at pH 5.0 and 70°C. The enzyme was stable over broad pH range of 4.0-7.0 with relative residual activity above 60% after 180 min of incubation. β-glucosidase demonstrated high thermostability with 83% of its original activity retained at 70°C after 180 min of incubation. The activity of β-glucosidase was enhanced by Mn(2+) and Fe(2+) with relative activities of 167.67% and 205.56%, respectively, at 5 mM and 360% and 315%, respectively, at 10 mM. The properties shown by β-glucosidase suggest suitability of the enzyme for industrial applications in the improvement of hydrolysis of cellulosic compounds into fermentable sugars that can be used in energy generation and biofuel production.
authors.affiliation: Enzyme Biotechnology and Environmental Health Unit, Department of Biochemistry, Federal University of Technology, Akure 340001, Nigeria.
authors.forename: Folasade M
authors.initials: FM
authors.lastname: Olajuyigbe
authors.affiliation: Enzyme Biotechnology and Environmental Health Unit, Department of Biochemistry, Federal University of Technology, Akure 340001, Nigeria.
authors.forename: Chidinma M
authors.initials: CM
authors.lastname: Nlekerem
authors.affiliation: Enzyme Biotechnology and Environmental Health Unit, Department of Biochemistry, Federal University of Technology, Akure 340001, Nigeria.
authors.forename: Olusola A
authors.initials: OA
authors.lastname: Ogunyewo