一株产几丁质酶菌株的筛选鉴定与产酶条件优化

摘要

几丁质酶在降解几丁质和生物防治上具有重要作用.采用平板筛选法从对虾养殖池塘底泥中筛选几丁质酶产生菌株,以培养时间、培养温度和胶体几丁质含量为自变量,响应面法优化该菌株的产酶条件,建立二次回归方程.试验结果表明,通过菌株的菌落形态、亚显微形态特征和16S rDNA序列同源性分析,确定该菌株为蜂房芽孢杆菌.3个因素对菌株产酶的影响依次为培养时间>培养温度>胶体几丁质含量.菌株的最佳产酶的条件为:培养基中胶体几丁质含量1.62%,培养温度40 ℃,培养时间72 h,在此条件下,菌株产生的几丁质酶活力为13.07 U/mL.该研究为筛选菌株的进一步利用提供科学依据.%Chitinase plays an important role in the degradation of chitin and biological control.A chitinase-producing strain was screened from prawn-farming pond sediment using plate screening method.The cul-ture temperature,culture time and the content of colloidal chitin as independent variables,the enzyme pro-duction condition of the strain was optimized using a response surface method,and quadratic regression e-quation was established.The results showed that the strain was determined as Paenibacillus alvei through colony morphology,submicroscopic morphology and 16S rDNA sequence homology analysis.The influ-ence of three factors on the enzyme production of the strain was expressed as culture time>culture temper-ature>content of colloidal chitin.The maximal enzyme production was observed under conditions of col-loidal chitin content of 1.62% in culture medium,the temperature of 40 ℃,and the culturing time of 72 h,with chitinase activity of 13.07 U/mL.The findings provided scientific basis for further utilization of the screened strain.