为提高枯草芽孢杆菌产生淀粉酶能力,从养虾池、混养池及污染河流的底质活性污泥中分离到12株枯草芽孢杆菌,通过淀粉降解试验筛选到产酶能力较高的菌株H4和H,菌株淀粉酶活性分别为38.66,37.10 U/mL.以筛选到H4和H为原始菌株,采用紫外诱变的方法对H4和H进行连续诱变筛选产淀粉酶高的突变株.结果发现,第一次诱变后突变株的酶活分别为原始菌株的107%和111%;经过第二次诱变后,H4的突变株H4 Ⅱa,H的突变株HⅡa和HⅡb的产酶能力有很大程度的提高,分别为原始菌株的147%,136%和13%,酶活达6.9,0.47和0.02 U/mL,说明紫外连续诱变有利于突变株产酶能力的提高.

Bacillus subtilis used as probiotic was widely applied to the aquiculture to purify the water with the needs of healthy breeding. In this paper twelve Bacillus subtilis strains were isolated from activate sludge of breeding shrimp pond,breeding fish pond and polluted river. H4and H5with high amylase activity were screened from the isolated strains by amylum degradation experiment and the activities of amylase were 38. 66,37. 10 U/ mL,respectively. The mean of ul2 traviolet continuous induced mutation was used on H4and H5. The results showed that the extracellular amylase activities of first mutant strains H4Ⅰ and H5Ⅰ were 41. 36 and 41. 32 U/ mL,which were 107 % and 111 %of initial strains. While the extracellular amylase activities of second mutant strains H4Ⅱ a,H5Ⅱ a and H5Ⅱ b were increased to 147 %,136 % and 135 % of initial strains,and the activities of amylase were 56. 95,50. 47 and 50. 02 U/ mL,respectively. The results indicate that ultraviolet continuous induced mutation would be in favor of the amylase producing of mutant strain.