[ Objective] The research on the strain producing the chitosan with high activity, mutated with ultraviolet and diethyl sulfate(DES) was conducted. [ Method] One strain of high-yielding chitosanase was isolated in the selective medium with the chitosan as sole carbon source and then was identified. Its ability in enzyme producing was improved through the treatment of UV and DES mutation. [ Result] The preliminary identification indicated that the strain Y-4 producing the chitosanase might be one of Aspergillus fumigatus. The activity of two mutants, which was from the treatment of UV and DES, was 8.92 and 8.12 U/ml,respectively, which was 3.0 and 2.7 times of the strain Y-4 (3.00 U/ml),respectively. Two mutant strains had been stable in enzyme production after serial of 10 generations. [ Conclusion] The effect of the ultraviolet radiation mutagenesis was better than that of DES.%[目的]研究利用紫外线和硫酸二乙酯(DES)诱变得到产壳聚糖酶活性较高的菌株.[方法]利用以壳聚糖为唯一碳源的选择性培养基,从自然界中筛选得到1株产壳聚糖酶活较高的菌株,对其进行鉴定,并且利用紫外线和DES诱变方法来提高该菌株的产酶能力.[结果]经初步鉴定,大致判定产壳聚糖酶的Y-4菌株为烟曲霉(Aspergillus,fumigatus).经紫外线和DES诱变处理分别得到2株壳聚糖酶活性明显提高的突变株,其酶活分别为8.92和8.12 U/ml,分别是出发菌株Y-4(3.00 U/ml)的3.0和2.7倍.2株突变株经连续传代10次后均具有较高的产酶稳定性.[结论]紫外线诱变较DES诱变效果好.
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