Abstract: Twelve lactic acid bacteria strains were isolated from pickled cabbage juice and then a superior plantaricin-producing strain,Lactobacillus plantarum LABR-X was screened out from them by diethyl sulfate(DES) mutation.The culture conditions for producing plantaricin by the Lactobacillus plantarum LABR-X were optimized and its biological features were investigated.The optimal culture conditions were determined by orthogonal test as follows:culture temperature 37 ℃,initial pH of culture medium 6,culture starter amount 5%(V/V),and proportion of liquid medium volume in fermentation container 60%.The plantaricin produced by the Lactobacillus plantarum LABR-X is a kind of antibacterial peptide.It has perfect heat resistance and is sensitive to trypsin and proteinase-K.Its antimicrobial activity is the strongest at pH 5 to 7.The antibacterial peptide can be developed as a natural food preservative or feed additive.

Key words: Lactobacillus plantarum, DES mutation, antibacterial peptide, culture condition, biological feature