目的:获得产高活性豆豉溶栓酶的枯草芽孢杆菌突变株。方法:用紫外诱变得到突变株,观察诱变效应,筛选透明圈直径与菌落直径比值大(HC值)的突变株,进行原生质体融合,筛选酶活高的菌株。结果:紫外诱变得到2株HC比值大的菌落;当溶菌酶为100 mg.L-1,处理时间为45 min进行原生质体融合时,效果最好;当PEG为40%时,原生质体融合率最大;最后筛选出酶活可达2 013 U.mL-1的突变株。结论:通过紫外诱变和原生质体融合,得到高活力的菌株。 OBJECTIVE: To obtain a Bacillus subtilis mutant with high activity of bean thrombolytic enzyme. Methods: The mutants were obtained by UV mutagenesis. The mutagenic effects were observed. Mutants with large clear circle diameter and colony diameter ratio (HC value) were screened for protoplast fusion and the strains with high enzyme activity were screened. Results: Two strains with large HC ratio were obtained by UV mutagenesis. When lysozyme was 100 mg.L-1 and the treatment time was 45 min, the best results were obtained when protoplast fusion was performed. When PEG was 40%, protoplast fusion The highest rate; finally selected mutant activity of up to 2 013 U.mL-1. Conclusion: High-activity strains were obtained by UV mutagenesis and protoplast fusion.