内切壳聚糖酶在食品级壳寡糖酶法生产中的应用

研究1株曲霉JXSD-01发酵液中内切壳聚糖酶(eCSN)的纯化与功能，以寻求一种清洁的生产不含单糖的壳寡糖的方法。经分析，不含外切酶活性的eCSN蛋白酶比活力＞50U/mg，分子质量为25kD，酶的最适温度为63℃，最适pH6.5。经N末端测序，内切壳聚糖酶的N端序列为YNLPNNLKQ。eCSN用于天然大分子壳聚糖的生物降解，可获得分子质量在1000～3500D的寡糖聚合物，其中无单糖污染，达到国际食品级壳寡糖质量标准。

Application of Endo-chitosanase in Enzymatic Preparation of Food-grade Oligo-chitosan

In order to obtain a novel and clean preparation process for food-grade oligo-chitosan without monosaccharide, an endo-chitosanase (eCSN) that can degrade chitosan was purified from fermentation broth of Aspergillus JXSD-01 and its properties were also explored. The specific activity of the eCSN was above 50 U/mg, and its molecular mass was approximately 25 kD. The optimal reaction temperature and pH of the enzyme were 63 ℃ and 6.5, respectively. The sequence of N-terminal in the enzyme was YNLPNNLKQ. The eCSN could used for the degradation of chitosan as a natural large molecule to produce oligosaccharides with molecular weights in the range of 1000－3500 D. The obtained oligosaccharides did not contain monosaccharides and could reach the international quality standard for food-grade oligo-chitosan.