Purification, characterization and end product analysis of dextran degrading endodextranase from Bacillus licheniformis KIBGE-IB25

Abstract

Degradation of high molecular weight dextran for obtaining low molecular weight dextran is based on the hydrolysis using chemical and enzymatic methods. Current research study focused on production, purification and characterization of dextranase from a newly isolated strain of Bacillus licheniformis KIBGE-IB25. Dextranase was purified up to 36 folds with specific activity of 1405U/mg and molecular weight of 158kDa. It was found that enzyme performs optimum cleavage of dextran (5000Da, 0.5%) at 35°C in 15min at pH 4.5 with a Km and Vmax of 0.374mg/ml and 182µmol/min, respectively. Relative amino acid composition analysis of purified enzyme suggested the presence of higher number of hydrophobic, acidic and glycosylation promoting amino acids. The N-terminal sequence of dextranase KIBGE-IB25 was AYTVTLYLQG. It exhibited distinct amino acid sequence yet shared some inherent characteristics with glycosyl hydrolases (GH) family 49 and also testified the presence of O-glycosylation at N-terminal end.