Characterization of a lichenase isolated from soil metagenome = 메타게놈유래 리치네이즈

Abstract

A lichenase gene (mt-lic) was identified for the first time through function-based screening of a soil metagenomic library. Its deduced amino acid sequence exhibited a high degree of homology with endo-β-1,3-1,4-glucanase having both lichenase and chitosanase activities, encoded by the bgc gene of Bacillus circulans WL-12. The recombinant lichenase overexpressed and purified from Escherichia coli was able to efficiently hydrolyze both barley β-glucan and lichenan. The enzyme showed maximal activity at a pH of 6.0 at 50°C, with Azo-barley-glucan as the substrate. The metal ions Mn2+, Mg2+, Ca2+, and Fe2+ enhanced the enzymatic activity, whereas the Cu2+ and Zn2+ ions inhibited the enzymatic activity. The Km and Vmax values of the purified lichenase were determined to be 0.45 mg/ml and 24.83 U/min per mg of protein, respectively