N-acetylation in chitosan and the rate of its enzymic hydrolysis

Partially N-acetylated derivatives (degree of substitution (d.s.) 0.2, 0.4, 0.6 and 0.8 for N-acetyl) of chitosan were prepared from prawn shell chitosan, and their susceptibility towards a lysozyme from hen egg-white, three microbial chitinases and a chitinase from potato skins was examined. The partially N-acetylated derivatives (d.s. 0.4-0.8 for N-acetyl) were 1.5-4.0 times more digestible than N-acetylchitosan (d.s. 1.0 for N-acetyl), and their enzymic hydrolysis rate is controlled by the d.s. for N-acetyl group. These data suggest that chitosan is usable as a digestible material in the biomedical and biotechnological fields.