Purification and Properties of Extracellular β-Glucosidase from the Antarctic Yeast Strain Cryptococcus Albidus AL3

L. KOLEVA1, I. PISHTIYSKI1 and K. PAVLOVA2
1 Department of Biochemistry and Molecular Biology, University of Food Technology, BG - 4002 Plovdiv, Bulgaria
2 Laboratory of Applied Microbiology, Institute of Microbiology, Bulgarian Academy of Sciences, BG - 4002 Plovdiv, Bulgaria

Abstract

KOLEVA, L., I. PISHTIYSKI and K. PAVLOVA, 2006. Purification and properties of extracellular β-glucosidase from the Antarctic yeast strain Cryptococcus albidus AL3. Bulg. J. Agric. Sci., 12: 713-720

Extracellular β-glucosidase from the Antarctic yeast strain Cryptococcus albidus AL3 was isolated and purified by ultrafiltration, ion exchange chromatography and gel filtration. The purity of the enzyme preparations obtained was controlled by SDS-PAGE. The enzyme activity after gel filtration was 109 U/mg protein, the pH optimum was 5.0 and the temperature optimum was 45 °C. This enzyme retained 18 - 20 % activity at 10 °C. It was inhibited by glucose and activated by ethanol. Some metal ions sach as Cu+2, Mg+2 and Mn+2 stimulated β-glucosidase activity, but it was inhibited by Hg+2 and Pb+2. The enzyme was active against different β-glucosides. The kinetic parameters for p-Nitrophenil-β-D-glucopyranoside were Km 0.64 mMol and Vmax - 140 U/mg.

Key words: Antarctic yeast, β-glucosidase, isolation, purification