Preparation of D-glucosamine by hydrolysis of chitosan with chitosanase and β-D-glucosaminidase.

Crude enzymes including chitosanase and β-D-glucosaminidase were obtained by centrifugal separation from the fermentation broth of Microbacterium sp. OU01. Then the crude enzymes are used to hydrolyze chitosan for producing D-glucosamine (GlcN). The effects of temperature, pH, substrate concentration, the ratio of enzyme to chitosan, and hydrolysis time on the productivity of GlcN were discussed. The experimental result showed that the optimal conditions were temperature 50 °C, pH 5.8, substrate concentration 20 mg/mL, the optimum ratio of enzyme to chitosan 1.5 U/60 mg. Under above conditions, chitosan was completely hydrolyzed in 5 h. These results provide a scientific material for the optimization process of enzymatic production of GlcN. What is more, thin layer chromatography and high performance liquid chromatography were used to analyze hydrolytic product, which was proved to be GlcN.