【摘要】 在摇瓶条件下,对大肠杆菌CD-2发酵生产过程中的主要培养基组成对产偶氮还原酶的影响进行了研究。根据响应面法,以单因子试验结果为基础,利用Plackett-Burma设计对影响E.coli CD-2产偶氮还原酶的相关因子进行了评估,并筛选出具有显著效应的3个因子:pH值、MgCl2、Na2HPO4。用最陡爬坡试验逼近以上3个因子的最大响应区域后,采用design expert 7.0统计软件的Box-Behnken设计以及响应面分析法,确定E.coli CD-2优化后的最佳培养基组成:甘露醇2 g.L-1、氯化铵3 g.L-1、接菌量5%、pH值为6.5、KH2PO42 g.L-1、Na2HPO46 g.L-1、MgCl20.99 g.L-1,优化后的酶活达到2.429 U.mL-1,是初始酶活的2.85倍。从而增强了E.coli CD-2所产的偶氮还原酶实际应用于污水处理的能力。更多还原

【Abstract】 The effects of culture medium composition on azoreductase produced by Escherichia coli CD-2 were studied using the shaking-flask method.A Plackett-Burman design was used to investigate the effects of different factors on azoreductase production based on the results of single-factor experiment.Three statistically significant factors,pH value,MgCl2 concentration,and Na2HPO4 concentration,were obtained,and then the steepest ascent procedure was employed to define the optimal response region for these three factors.Finally,Box-Behnken and response surface methodology were applied to determine the composition of the culture medium optimized for the production of azoreductase by Escherichia coli CD-2.The optimal medium composition for azoreductase production was obtained as mannitol concentration 2 g·L-1,NH4Cl concentration 3 g·L-1,inoculation amount 5%,pH 6.5,KH2PO4 concentration 2 g·L-1,Na2HPO4 concentration 6 g·L-1,and MgCl2 concentration 0.99 g·L-1.The azoreductase activity after optimization increased from 0.852 3 to 2.429 U·mL-1.Azoreductase produced by Escherichia coli CD-2 has a great potential in wastewater treatment.更多还原