Functional genes with probiotic potential isolated from fruits and vegetables

Lactobacillus plantarum strains isolated from various food sources and different climatic regions were genetically characterized at subspecies level with recA gene based multiplex PCR amplifications and pulsed-field gel electrophoresis (PFGE), and next generation sequencing of the strains was done. Five strains were identified as Lactobacillus plantarum AS-6, AS-7, AS-8, AS-9 and AS-10. Stress related proteins encoding genes were also identified in the probiotic strains, we hypothesized that the antimicrobial activity of Lactobacillus plantarum strains was associated with plantaricin biosynthesis gene clusters products, class II bacteriocins. Indeed, plantaricin biosynthesis gene clusters were identified i.e. bacteriocin operons plnEFI, plnABCD, regulatory operon plnA, transport operon plnGHSTUVW. All the strains were tested for the production of bacteriocin against major food borne pathogens (L. innocua and L. monocytogenes). Moreover, acid tolerance, NaCl tolerance, survival in simulated gastric juice, bile salt hydrolase activity, and antibiotic resistance of these strains were also analysed. Identification of gene encoding bacteriocin (plantaracin 423), along withenzyme sensitivity assays to protinease K and pepsin were also performed.