产蛋白酶嗜热菌Anoxybacillus sp.紫外诱变研究

Research on UV mutagenesis of protease-producing strain of thermophilus Anoxybacillus sp.

目的对嗜热菌Anoxybacillus sp.进行紫外诱变,通过改变遗传性状获得产蛋白酶性能优良的嗜热菌株。方法用牛奶平板对嗜热菌株产蛋白酶能力进行初步判断;将菌悬液置于紫外灯下照射不同时间,分别进行菌落计数、计算致死率;以紫外诱变后致死率75%~85%的诱变时间处理菌悬液,采用Folin法对紫外诱变前后的菌株所产蛋白酶的活性进行检测比较;诱变处理的菌液连续传5代,每代检测蛋白酶的活性。结果嗜热菌Anoxybacillus sp.可在牛奶平板上产生清晰透明的蛋白水解圈;Anoxybacillus sp.DL4菌株经90s紫外照射处理后的致死率为81.46%;突变株的酶活性提高了17.33%;菌株传代5次,每代蛋白酶活性基本相同。结论紫外诱变能够明显提高嗜热菌Anoxybacillus sp.DL4的蛋白酶活性,且其遗传稳定性较好。

Objective To conduct UV mutagenesis on thermophilus Anoxybacillus sp.,in order to obtain better protease-producing strain of thermophilus with changing the hereditary character. Methods The strain capacity of protease-producing on milk agar plate was estimated.After UV irradiating the strain for different time,the number of colonies and the fatality rate were calculated respectively. Bacterial liquid was disposed for the time when the fatality rate of the strain was 81. 46% after UV mutagenesis. The protease-produced ability of the strain before and after UV mutagenesis were compared by detecting the activity of protease with the Folin method. The strain was passaged five times after UV mutagenesis and assayed protease activity for every time. Results Thermophilus Anoxybacillus sp. had the hydrolysis circle on milk agar plate. The fatality rate of Anoxybacillus sp. DL4 was 81. 46% after UV irradiating the strain for90 s. The protease activity of mutant strain was enhanced by 17. 33% in comparison with that of the parent strain. Passaged five times,the protease activity was almost the same. Conclusion The protease activity of the thermophilus Anoxybacillus sp. DL4 is improved significantly and has the better hereditary stability after UV mutagenesis.