原生质体诱变结合复合抗性筛选杆菌肽高产菌株

目的]筛选杆菌肽的高产菌株。方法]将原始菌株经活化后制备原生质体，采用紫外照射75s后再用终浓度为100μg／ml的NTG诱变通过硫酸链霉素＋杆菌肽复合抗性平板筛选杆菌肽的高产菌株。结果]经过7轮诱变，一共分离了1000个菌株（筛选过的所有菌株）；最终获得C-67号高产菌株，其杆菌肽效价达到963．2957U／ml，相比原始菌株提高22．34％。C-67连续传代5次后，产量仍稳定，表明其遗传稳定性较高。结论]原生质体诱变结合复合抗性筛选是一种简单高效的微生物育种及筛选方法。

Screening of High Bacitracin-producing Strains by Protoplast Mutagenesis Combined with Antibiotics Resistance Plates

Objective ] To screen high bacitracin-producing strains. Method ] In order to increase the production capacity of bacitracin by strains of high yield of Bacillus licheniformis, the protoplasts of the initial strain, Bacillus licheniformis FNU-BL6 are mutagenized by UV irradia-tion for 75 s combined with NTG at a final concentration of 100 μg/ml. Result] The mutagenized protoplasts were spread on the screening plates containing bacitracin and streptomycin sulfate. A high yield strain, C-67, was obtained from the streptomycin sulfate ＋ bacitracin resistant plates. Its bacitracin titer was 963. 295 7 U/ml and increased 22.34% to that of the initial strain. Strain C-67 kept a stable product ability in five genera-tions. Conclusion] Protoplast mutagenesis following the antibiotics resistance screening program was a simple and efficient procedure for micro-bial breeding and selection.