Purification and characterization of extracellular chitinase produced by marine bacterium, Bacillus sp. LJ-25

Abstract

Extracellular chitinase was purified from the culture liquid of the marine bacterium, Bacillus sp. LJ-25, and its enzymatic properties, were examined. The purified chitinase exhibited a single band on SDS-PAGE and the molecular weight was estimated to be approximately 50 kDa. The optimum pH and temperature for the enzymatic activity were 7.0 and 35°C, respectively. The activity of the chitinase was strongly inhibited by Zn2+ and slightly inhibited by Ba2+, Co2+, Mn2+, and Cu2+. The purified chitinase did not hydrolyze p-nitrophenol-N-acetyl-β-D-glucosaminide (GlcNAc)2 and Micrococcus lysodeikticus cells, which are known to be the substrates for exo-type chitinase. Among the hydrolyzates of colloidal chitin, (GlcNAc)2 was in the highest concentration with small amounts of GlcNAc and (GlcNAc)3.