Enzymatic Degradation of Chitosan

The enzymatic degradation of chitosan was performed in a bioreactor by the chitoanase from aspergillus niger,and the effects of temperatrue,pH,chitosan concentration and metal ions were investigated.Chitooligosaccharides with average polymerization degree less than 10 were obtained after the chitosan was degradated by the chitoanase for 5 h.The optimal temperatrue,pH,substrate concentration of the degradation reation are 50 ℃,5.5 and 0.02 g/mL,respectively.It was found that ions Ca~(2+) and Mg~(2+) stimulated the chitoanase activity significantly,while Zn~(2+) and Cu~(2+) had inhibitory effects.The enzymatic degradation reaction is in accord with the Michaelis-Menton Equation,and the kinetic parameters K_m = 7.80 g/L,V_(max) = 7.72 g/(min·L).