Study on screeging of high-yield bacteriocin producing Lactobacillus plantarum stains induced by mutations

In order to obtain a high- yield bacteriocin producing strain,Lactobacillus plantarum JLA-9 was used as the starting stain and mutagenized with nitrosoguanidine( NTG),atmospheric and room temperature plasma( ARTP) and genome shuffling.The results showed that the optimal concentration of NTG was 4 mg / m L,and two mutants named N4- 26,N4- 27 were obtained,the antibacterial titer of which were 2531.93 IU / m L,3057.32 IU / m L respectively. The optimal irradiation time of ARTP was 10 s,and two mutants named ARTP10- 37,ARTP10- 61 were obtained,the antibacterial titer of which were2974.27 IU / m L,3261.62 IU / m L respectively. The four strains with higher inhibitory activity were subjected to recursive protoplast fusion.After four rounds of genome shuffling,a strain named F4-2 was screened.The antibacterial titer of strain F4-2was increased to 7374.76 IU / m L,2.35 times compared with the wild- type strain.Research showed that physical and chemical mutagenesis combined with genome shuffling was an effective method for obtaining ideal strains.