中温α-淀粉酶高产菌株的选育及其粗酶性质

摘要

A α-amylase producing strain was isolated and identified as Bacillus subtilis. After the treatments of UV and UV-LiC1, a high-producing α-amylase mutant （XLG-51） was obtained. Further study showed that the α-amylase produced by XLG-51 was fairly thermo stable and acid stable, and the optimum temperature and pH were 60℃ and 5.5 respectively. SDS-starch-PAGE electrophoresis and enzymography analysis revealed that the enzyme had a molecular weight of about 60 ku. Furthermore, the experiment was amplified on 5 L fermentor and the yield of enzyme activity was 5298 U/mL%以从自然界中筛选的野生芽孢杆菌XLG-1为出发菌株，通过紫外线诱变及紫外线．氯化锂复合诱变筛选出高产中温α-淀粉酶的优异菌株XLG-51，经鉴定为枯草芽孢杆菌（Bacillussubtilis）。初步研究了其所产的饯．淀粉酶的酶学性质：通过SDS—starch—PAGE电泳与酶谱分析得该酶分子质量为60ku左右，最适作用温度为60℃，最适作用pH范围为5．0～6．5，且在最适条件下具有较强的稳定性。以该菌株为生产茵进行5L罐发酵实验。产酶达5298U／mL。