Cloning， Expression， Purification and Analysis of Enzymic Properties of Thermostable β-glucosidase from the Thermophilic Fungus

Abstract: The β-glucosidase bg1II gene was cloned from thermophilic fungus Thermoascus aurantiacus var. levisporus. The accession number in GenBank is EU263992. The gene was ligated with the Pichia pastoris expression vector pPIC9K， resulting in the recombinant plasmid. The recombinant plasmid was transformed into P. pastoris. Highly efficient β-glucosidases from project strain were achieved through massive screening. The project strain was induced with methanol in 6 d. The β-glucosidase was expressed and secreated into the culture with activity of 0.23 U/mg. The β-glucosidase exhibited optimum catalytic activity at 50 ℃ and pH 5.0. The recombinant β-glucosidase was purified by using DEAE-Sepharose Fast Flow chromatography. A molecular mass of the purified enzyme is 118 kDa determined by SDS-PAGE

CSTR: 32200.14.cjcb.2009.04.0013