Specificity of chitosanase from Bacillus pumilus

Abstract Partially (25–35%) N -acetylated chitosan was digested by chitosanase from Bacillus pumilus BN-262, and structures of the products, partially N -acetylated chitooligosaccharides, were analyzed in order to investigate the specificity of the chitosanase. The chitosanase produced glucosamine (GlcN) oligosaccharides abundantly, indicating that the chitosanase splits the β-l,4-glycosidic linkage of GlcN-GlcN. The chitosanase also produced hetero-oligosaccharides consisting of glucosamine and N- acetyl- d glucosamine (GlcNAc). Three types of the hetero-oligosaccharides purified by cation-exchange chromatography and HPLC were found to have GIcNAc residue at their reducing end and GIcN residue at their non-reducing end, indicating that the chitosanase can also split the linkage of GlcNAc-GlcN. The determination of the mode of action toward partially N -acetylated chitosan enables a classification of chitosanases according to their specificities and a more precise definition of chitosanases.