Study on Mutation Breeding of High-Yield Bacteriocin Lactobacillus plantarum by Heavy Ion Beam Irradiation

The heavy ion beam of ¹²C⁶⁺ was used to irradiate the original strain Lactobacillus plantarum Lp1 of bacteriocin-producing. The lethality and mutation rate of theoriginal strain Lp1 at different irradiation doses were analyzed and compared, and the mutant strains with high bacteriocin production were screened by double layer agar diffusion method. At the irradiation dose of 300 Gy, the lethality rate and positive mutation rate of the original strain Lp1 were 86.3% and 28.28%, respectively.In the 300 Gy irradiation bacterial suspension, mutant strains Lp092 and Lp085 with high bacteriocin production were isolated and screened, the diameters of inhibition zones of Escherichia coli as the indicator bacteria were increased by 20.64%, 19.36%, the diameters of inhibition zones of staphylococcus aureus as the indicator bacteria were increased by 17.16%, 14.14% than the original strain Lp1, respectively.After 5 times successive generations, 2 strains Lp092 and Lp085 have good genetic stability for bacteriocin production.