Molecular genetic studies of pediocin-like bacteriocin in pediococcus, lactobacillus and enterococcus sp

Abstract

The aim of the study was to isolate intergeneric or interspecific lactic acid newlinebacteria (LAB) producing the pediocin the pediocin PA-1 like bacteriocin from newlinedifferent sources. The isolates obtained from vegetable sources displayed strong antilisterial newlineactivity and considered for further characterization. The pediocin specific newlinegene PCR and dot-blot hybridization helped in the rapid detection of the pediocin PA- newline1 like bacteriocin. Further, the culture filtrate (CF) of the selected isolates was found newlineto have class IIa bacteriocin properties, which include, stability at wide temperatures newlineand pH, proteinaceous in nature and the anti-microbial peptide was found to be 4.6 newlineKDa. The physiological, biochemical and molecular typing techniques like RAPD and newlineRFLP, followed by 16S rDNA sequencing confirmed the taxonomical status of the newlineLAB producing the putative pediocin PA-1 like bacteriocin. The isolates were newlineidentified as Streptococcus equinus AC1 NCIM 5418, Pediococcus acidilactici NCIM newline5419, Ped. pentosaceus NCIM 5420, Lactobacillus plantarum Acr2 and, three isolates newlineof Enterococcus faecium NCIM 5421, NCIM 5422 and NCIM 5423, respectively. The newlinebacteriocin production at different temperatures, pH and salt concentrations was newlinestudied to investigate the optimal condition for application of these isolates as a starter newlineculture or as a biopreservative in either acidic or non-acidic foods newlineThe isolates Pediococcus acidilactici NCIM 5419 and NCIM 5424, Ped. newlinepentosaceus NCIM 5420, Enterococcus faecium NCIM 5423 and Lactobacillus newlineplantarum Acr2 were selected to determine the genetic determinants of the newlinebacteriocin encoded. The use of class IIa bacteriocin specific primers, plasmid curing, newlineimmunity assay and Southern hybridization with pedB as probe, revealed that all the newlineisolates produced plasmid encoded pediocin PA-1 like bacteriocin. It was observed by newlinePCR analysis that the selected isolates had a conserved operon arranged in pedABCD newlineorder.