Cloning, expression and characterization of a novel chitosanase from Streptomyces albolongus ATCC 27414

A gene encoding chitosanase from Streptomyces albolongus was cloned, sequenced and expressed in Escherichia coli. The novel recombinant enzyme (Csn21c) was purified by Ni-NTA Superflow Column and showed a molecular mass of 29.6 kDa by SDS-PAGE. The enzyme Csn21c showed the optimal activity in 50 mmol/L Tris-HCl buffer, pH 8.0, and 50 degrees C and it was strongly activated (2-fold) by Mn2+. It belonged to glycoside hydrolase 46 family according to NCBI database (http://www.ncbi.nlm.nih.gov/) and displayed an exo-type cleavage pattern, hydrolyzing chitosan mainly into D-glucosamine (GlcN) and chitobiose ((GlcN)(2)) as confirmed by TLC and MS analysis. This study demonstrated that Csn21c can be an effective tool to produce abundant glucosamine and chitooligosaccharides (COS) from chitosan.