Objective:In order to overcome the defects of chemical hydrolysis approach to prepare glucosamine,an enzymatic hydrolysis method was developed.Methods:Glucosamine was prepared by hydrolyzing chitosan,employing α-amylase initially,and subsequently,glucoamylase.Results:The optimal hydrolyzing conditions were as follows:reaction time,4 h;pH,5.0;temperature,50 ℃;and,α-amylase,80 U/g for the initial reaction.Subsequently,glucoamylase was added in the presence of α-amylase.The optimal reaction conditions were found to be:reaction time,8 h;pH,4.5;temperature,55 ℃;and,glucoamylase,4 000 U/g.The hydrolysates were subject to filtrating,concentrating to about 20%(w/w),precipitating with five volumes of ethanol,and drying at 60 ℃ for 2 h.The content and the yield of glucosamine in the dried precipitate were 91.3%(w/w) and 86.2%(w/w),respectively.Conclusions:The method developed in this study is a promising option in the preparation of glucosamine. Objective: In order to overcome the defects of chemical hydrolysis approach to prepare glucosamine, an enzymatic hydrolysis method was developed. Methods: Glucosamine was prepared by hydrolyzing chitosan, employing α-amylase initially, and subsequently, glucoamylase. Results: The optimal hydrolyzing conditions were as follows: reaction time, 4 h; pH, 5.0; temperature, 50 ° C .; and, α-amylase, 80 U / g for the initial reaction. Published, glucoamylase was added in the presence of α-amylase. The optimal reaction conditions , glucoamylase, 4 000 U / g. The hydrolysates were subject to filtrating, concentrating to about 20% (w / w), precipitating with five volumes of ethanol, and drying at 60 ° C for 2 h. The content and yield of glucosamine in the dried precipitate were 91.3% (w / w) and 86.2% (w / w), respectively. Conclusions: The method developed in this study is a promising option in the preparation of glucosamine.