湘江河岸土壤中高产甲壳素脱乙酰酶菌株的筛选及鉴定

【目的】甲壳素脱乙酰酶(CDA)是将天然甲壳素生物转化为可商品化利用的壳聚糖的关键酶。本文旨在从湘江河岸的土壤中筛选可高产CDA的新菌株。【方法】以甲壳素为唯一碳源,利用4'-硝基乙酰苯胺为显色剂,通过变色圈法进行产CDA菌株初筛,产酶活性分析复筛;通过形态学和ITS区序列特征对菌株进行鉴定。【结果】从湘江(长沙段)河岸边的土壤中分离出的117株菌株中筛选到可产CDA的菌株30株,其中4株具有较强产CDA的能力。进一步经发酵产酶分析验证,菌株A1具有较强的产CDA能力,其胞外CDA酶活高达13.21 U/m L。结合形态学和ITS区序列特征,菌株A1初步鉴定为层生镰孢菌。【结论】从湘江河岸边的土壤中筛选到可高产CDA的菌株A1,具有较好的开发应用前景。

Isolation of chitin deacetylase-producing microorganisms from riverside soils of Xiangjiang of China

[Objective] Chitin deacetylase is a key enzyme in the conversion of natural chitin into chitosan, which can be commercially used. The aim of this work is to screen a new strain with high capacity for producing chitin deacetylase. [Methods] Chitin deacetylase producing strains from soils of Xiangjiang riverside in Changsha area were preliminarily screened with chitin as only source of carbon by color reaction of 4''-nitroacetanilide, and further screened by enzyme activity analysis; Identification of strains was analyzed by morphological and internal transcribed spacer (ITS) sequence. [Results] We isolated 117 starins from soils of Xiangjiang riverside, thirty strains had the potential producing chitin deacetylase ability, and among which, four potential strains had the most high capacities, and validation of enzyme activity analysis suggested that strain A1 had the highest capacity for producing chitin deacetylase, the extracellular enzyme activity reached 13.21 U/mL. On the basis of morphological and ITS sequence identification, strain A1 was preliminarily identified as Fusarium proliferatum. [Conclusion] We obtained a F. proliferatum strain isolated from soils of Xiangjiang riverside with high capacity for producing chitin deacetylase.