Detection and characterization of pediocin PA-1/AcH like bacteriocin producing lactic acid bacteria

Fifty-five bacteriocinogenic lactic acid bacteria (LAB) isolated from seven different sources. Eight isolates were found to produce pediocin PA-1 like bacteriocin as detected by pedB gene PCR and dot-blot hybridization. The culture filtrate (CF) activity of these isolates exhibited strong antilisterial, antibacterial activity against tested food-borne pathogens and LAB. The identification and genetic diversity among the selected LAB was performed by conventional morphological and molecular tools like RFLP, RAPD, and 16S rDNA gene sequencing. The isolates were identified as, 1 each of Pediococcus acidilactici Cb1, Lactobacillus plantarum Acr2, and Streptococcus equinus AC1, 2 were of P. pentosaceus Cb4 and R38, and other 3 were Enterococcus faecium Acr4, BL1, V3. Partial characterization of the bacteriocins revealed that the peptide was heat-stable, active at acidic to alkaline pH, inactivated by proteolytic enzymes, and had molecular weight around 4.6 kDa and shared the properties of class IIa pediocin-family. The bacteriocin production at different temperatures, pH, and salt concentrations was studied to investigate the optimal condition for application of these isolates as a starter culture or as a biopreservative in either acidic or non-acidic foods.