耐高温β-半乳糖苷酶产生菌诱变和突变菌株产酶特性

Mutation of thermostable β-galactosidase-producing strain and β-galactosidase producing characterization of mutan

以产β-半乳糖苷酶嗜热脂肪芽孢杆菌Bacillus stearothermophilus XG24为原始菌株,先后经微波辐照、亚硝基胍(NTG)诱变,选育获得1株高产突变菌株XGN52。产酶量比原始菌株提高了115.92%,其最大产酶量为31.59U/mL。经过10次传代实验,稳定性良好。突变菌株XGN52最适发酵时间36h,初始pH7.0,温度42℃。与原始菌株相比,突变株XGN52的产酶特性发生了改变。研究结果显示采用微波和NTG复合诱变对提高β-半乳糖苷酶产量具有显著的效果。

The thermostable β-galactosidase-producing strain Bacillus stearothermophi/us XG24 was used as an original strain which was induced by microwave and NTG for increasing the #-galactosidase production ability. One of the highest efficient β-galactosidase-producing mutants was named as XGN52 with its stable #-galactosidase production ability. Its cumulative β-galactosidase yield was 31.59U/mL,115.92% higher than that of the original strain. Varieties of parameters of β-galactosidase production fermentation were studied, including fermentation time,initial pH,incubation temperature. The result indicated the optimum condition of β-galactosidase production for the mutant XGN52 as fermentation time 36h,initial pH7.0 and temperature 42℃. The β-galactosidase production characters of the mutant and the original strain were different. This work showed a good application potential of microwave-NTG combined mutation in the β-galactosidase production.