To improve the ability of Bacillus subtilis in producing lysine,ten porcine Bacillus subtilis were applied to select and breed high-yield lysine strain.The strain as initial bacterium,which had highest lysine yield among them was treated with UV.The results showed that lysine content of supernatant of strain YB83 screened primarily was 179.39 mg/L, which was 22.58%higher than that of LB broth.After UV mutagenesis,the mutant strain YB83-U5 was steady hereditary, the lysine content of supernatant of which was 27...