Studies on reaction conditions of lysozymic hydrolysisof partially N-acetylated chitosans

摘要

Some hydrolysis conditions of partially N-acetylated chitosan (PNAC) by lysozyme were investigated in this paper. The results showed that: The optimum temperature and pH of the hydrolysis were 55℃ and 4.0 respectively. The PNACs with N-acetylation degree of about 30% (PNAC-30) showed higher digestibility by lysozyme at 55℃. From time-course curves, at the initial stage (about 30min), the rate of hydrolysis was very rapid; after then, it slowed down. The amount of reducing sugar in solution increased with the increase of the concentration of PNAC-30 and lysozyme. The PNAC-30 were hydrolyzed by lysozyme at optimum conditions for 120hs and the molecular weight of hydrolysates was determined by gel permeation chromatography (GPC). The GPC pattern showed that the molecular weight of hydrolysates mainly ranged from 5,5kDa to 15kDa. The yields of hydrolysates with the molecular weight lower than 3kDa were very large.