低温淀粉酶高产菌株的诱变选育

Mutagenesis Breeding of High-Yielding Strains from Low-Temperature Amylase

以一株解淀粉芽孢杆菌(Bacillus amyloliquefaciens)A-4为出发菌株,采用紫外线(UV)和亚硝基胍(NTG)诱变,以期筛选出高产低温淀粉酶量诱变菌株;经紫外线诱变、亚硝基胍诱变、紫外线-亚硝基胍复合诱变,所得突变菌株经淀粉酶平板水解圈初筛、再经摇瓶发酵复筛,得高产低温淀粉酶突变株UNA4-6,其最大产酶量62.13U/mL,是出发菌株A-4的1.96倍;将UNA4-6连续传代6次,低温淀粉酶活性仍可达到第一代的99.7%,试验表明遗传稳定性好。

As an original strain, an amyloliquefaciens Bacillus （Bacillus arnyloliquefaciens） A4 preserved in our laboratory was mutated by ultraviolet ray and nitroso guanidine respectively, the optimal induced mutation conditions were gained.A mutant strain named UNA4-6 with high-yielding low-temperature am- ylase activity was obtained though the screening of amylase flat and the rescreening of flask fermentation. The maximum amylase production of UNA4-6 was 1.96 times more than that of the original strain,The greatest amylase yield was 62.13 U/mL.If UNA4-6 were continuously handed from generation to genera- tion for 6 times,the activity of low-temperature amylase still can reach 99.7% of the first generation.The subcultures tests showed UNA4-6 has good genetic stability.