Induction of plantaricin MG under co-culture with certain lactic acid bacterial strains and identification of LuxS mediated quorum sensing system in Lactobacillus plantarum KLDS1.0391

A bacteriocin named plantaricin MG was produced by Lactobacillus plantarum KLDS1.0391 which was isolated from “jiaoke”, a traditional, naturally fermented cream from Inner Mongolia in China. Bacteriocin production was increased significantly when L. plantarum KLDS1.0391 co-cultured with certain lactic acid bacteria (LAB) strains. Among 76 strains belonging to the genera Lactobacillus, Lactococcus, Leuconostoc and Streptococcus, four strains namely Lactobacillus helveticus KLDS1.9207, Enterococcus faecium KLDS4.0352, Lactobacillus reuteri KLDS1.0737 and Enterococcus faecalis KLDS4.0313 were shown to induce bacteriocin production of L. plantarum KLDS1.0391. Cell numbers of L. plantarum KLDS1.0391 were greatly enhanced when co-cultured with four bacteriocin-inducing strains. Bacteriocin production was not induced by autoclaved cultures and cell-free supernatants (CFS) of inducing strains, indicating that living cells of inducing strains might be necessary for enhancement of bacteriocin production. The presence of plnD and luxS genes was detected by polymerase chain reaction (PCR), and the existence of plNC8HK gene was detected by single oligonucleotide nested PCR (SON-PCR).