【摘要】 目的：对海洋来源的具有产纤溶酶能力的枯草芽孢杆菌（Bacillus subtilis）LC6-1进行紫外诱变，得到高产且稳定的突变株PW6-3,对该突变株发酵产酶的条件进行优化。方法：采用单因素和正交试验进行发酵培养基组分和培养条件的优化。结果：突变株PW6-3的酶活力为（6 960.21±85.51）U/mL,较原始菌株提高了30.48%。以PW6-3为出发菌株，采用单因素及正交试验的方法对菌株进行发酵培养基组分与培养条件优化，最终得到的最佳培养基组分是：玉米淀粉30 g/L,玉米浆干粉40 g/L,CaCl₂ 3 g/L;最佳发酵培养条件是：32℃,转速200 r/min,接种量3%,pH 6.5,种龄18 h,发酵培养时间66 h,最终菌株的酶活力稳定在（9 203.63±67.85）U/mL。结论：发酵工艺优化后，菌株PW6-3纤溶酶产量较诱变之前的菌株LC6-1提高72.53%,且发酵工艺成本较低，具有较好的经济效益。更多还原

【Abstract】 Objective: Cardiovascular diseases caused by thrombus have severely impaired human health. However, there are most of defects on traditional thrombolytic agents, like high price, low fibrin specificity and side effect. Enzyme from marine environment are rarely reported and expected to be efficient and economical thrombolytic drugs. Methods: In this experiment, a mutant strain PW6-3 with high fibrinolytic activity was obtained by UV mutagenesis using the marine-derived Bacillus subtilis LC6-1. The acquire mutant PW6-3 was subjected to process optimization of fibrinolytic enzyme production. Results: The UV-mutagenized high-yielding mutant strain PW6-3 was（6 960.21 ± 85.51） U/mL, which was 30.48% higher than the initial strain. The medium components and culture conditions of strain PW6-3 in shake-flask were optimized by single factor and orthogonal experiments. The optimal medium components were: Corn starch 30 g/L, corn pulp dry powder 40 g/L, CaCl₂ 3 g/L. The optimal culture conditions were: Temperature of 32℃, speed of 200 r/min, loading volume of 50 mL in 250 mL flask, inoculation volume of 3%（v/v）, initial pH of 6.5, seed age of 18 h, fermentation time of 66 h. Conclusion: After fermentation optimization, the enzyme activity of strain PW6-3 reached（9 203.63 ± 67.85） U/mL, which was 72.53% higher than initial strain LC6-1. The optimized yield is at a high level in the world at present.更多还原