高产溶栓酶纳豆芽孢杆菌的选育及发酵工艺优化

Breed of High Yield Fibrinolytic Enzyme Strain by N^+ Implantation and Opitimization Fermentation Process

目的N+注入诱变选育纳豆芽孢杆菌,获得溶血栓酶高产菌株,优化发酵工艺。方法N+注入诱变纳豆芽孢杆菌,在摇瓶中进行发酵工艺优化。结果在N+注入剂量为3.64×1015ions·cm-2时,正突变率最高,突变株234表现出良好的稳定性。最佳发酵培养基和发酵条件为:碳源葡萄糖,氮源大豆蛋白胨,碳氮比3∶1(6%葡萄糖,2%大豆蛋白胨),起始pH7,温度30℃,接种量8%,装液量为每100mL为20mL。在最佳发酵工艺下,突变菌株234的产酶活性酶活达到1380U·mL-1。结论诱变选育的正突变株性状优良,N+注入诱变是一种有效的菌种选育方法。

OBJECTIVE To obtain a high producing fibrinolic enzyme mutant of Bacillus nattto and optimize the fermentation condition. METHODS Bacillus＇ nattto was mutated by N^＋ Implantation and fermentation condition was optimized in a shaking flask. RSEULTS Under the implantation dose of 3.64× 10^15 ions·cm^-2, the percentage of the positive mutated strain was high. Mutant strain 234 showed excellent genic stability. The optimal culture medium and fermentation condition was as following： carbon source was glucose, nitrogen source was soybean peptone, the ratio of carbon to nitrogen was 3 ： 1 （6% glucose, 2% soybean peptone）, original pH was 7, temperature was 30 ℃, innoculumon was 8%, seed liquid volume in a 100 mL flask was 20 mL.In the optimum process, the fibrinolic enzyme activity of strain 234 reached to 1 402 U·mL^-1. CONCLUSION The positive mutant was excellent and mutation by N^＋ implantation was useful for breeding strain.