重离子诱变作为一种新型高效的辐照诱变方式, 具有突变率高、突变谱广、突变体稳定等特点。枯草芽孢杆菌(Bacillus subtilis)因具有多种水解酶活力而广泛应用于工业生产, 虽然经过多次诱变和改造, 其酶活力不断提高, 但其复合酶活力仍有提升空间。同时, 多次同种诱变剂的使用容易导致菌种产生“抗性”, 酶活力提高不大。为此, 本研究首次利用不同剂量12C6+重离子束对枯草芽孢杆菌20076进行辐照诱变。诱变后通过透明圈初筛和酶活力验证复筛方式选育出一株复合酶活力较高的菌株B. subtilis KC-1。与原始菌株相比, 其发酵液滤纸酶活力、内切葡聚糖酶活力、β-葡萄糖苷酶活力、外切葡聚糖酶活力、蛋白酶活力和α-淀粉酶活力分别提高了20.2%、79.6%、98.2%、7.4%、10.4%和27.4%。11代遗传稳定性实验结果表明该突变株具有良好的稳定性。

As a new high efficiency irradiation mutation source, heavy ion mutagenesis has advantages of high mutation rate, broad mutation spectrum, and good genetic stability for mutants. Bacillus subtilis, which has a broad hydrolase system, is one of the most important bacteria for industrial application. In this research, Bacillus subtilis 20076 was irradiated by various doses of 12C6+ heavy ion beam to increase its enzyme production for industrial application. Based on transparent circle and enzyme activities, a target strain was obtained and named as KC-1. The strain showed an increase of 20.2%,79.6%, 98.2%, 7.4%,10.4%and 27.4%respectively in filter paper enzyme, endo-1,4-glucanase, β-glucosidase, exo-1,4-glucanase, protease and α-amylase when compared to the original strain. After the 11th passages, the mutant also had good stability in compound enzyme production.