紫外线和亚硝酸诱变选育高产α-环糊精葡萄糖基转移酶菌株

Breeding of high yield α-cyclodextrin glucosyltransferase strains by UV and nitrite mutagenesis

通过单因素实验,对已筛选出的产酶菌株N1进行诱变处理,结合甲基橙平板筛选和α-环糊精葡萄糖基转移酶(α-CGTase)活力测定,确定了紫外线和亚硝酸的诱变剂量,获得了一株α-CGTase活力较高的菌株B3。实验结果如下:距离20 W紫外灯30 cm,照射100 s,0.25 mol/L的HNO2处理30 min,效果较好。出发菌株N1酶活为0.62 U/mL,经过诱变获得高产菌株B3酶活力是3.76 U/mL,发酵生产的α-CGTase活力比原始菌株提高了506%。经8代稳定性实验,B3的活力稳定在3.760±0.030 U/mL。

In order to obtain a strain（ B3 ）with high ct -CGTase activity, the screened enzyme production strains N1 was treated by HNO2 and UV mutagenesis, screened by methyl orange plate, and determined for the α- CGTase activity. The dose of nitrous acid and UV was ascertained by single factor experiments. The results showed that the effect was good under the condition of being irradiated with 20 W UV lamp in the distance of 30 era,for 100 s and treated with 0.25 mol/L HNO2 for 30 rain. The enzyme activity of strain N1 was 0.62 U/mL,after mutagenesis the enzyme activity of the strain B3 reached to 3.76 U/mL. Compared with the original stain, the α-CGTase activity of the strain B3 increased by 506% , and kept in 3. 760 ± 0. 030 U/mL after eight generations.