title: Fluorescence-Based Comparative Evaluation of Bactericidal Potency and Food Application Potential of Anti-listerial Bacteriocin Produced by Lactic Acid Bacteria Isolated from Indigenous Samples.
abstract: The aim of the present study was to ascertain the potency of anti-listerial bacteriocin produced by lactic acid bacteria (LAB) isolated from indigenous samples of dahi, dried fish, and salt-fermented cucumber. A total of 231 LAB isolates were obtained from the samples, of which 51 isolates displayed anti-listerial activity. The anti-listerial LAB were identified by PCR as Lactobacillus sp., Pediococcus sp., Enterococcus sp., and Lactococcus sp. PCR also enabled the detection of Class IIa bacteriocin-encoding genes such as enterocin A, pediocin, and plantaricin A in some of the LAB isolates. The culture filtrate from anti-listerial LAB isolates demonstrated bacteriocin-like inhibitory substance (BLIS) against common Gram-positive pathogenic bacteria such as Staphylococcus aureus, Enterococcus faecalis, and Bacillus cereus, and partial characterization of BLIS confirmed the production of bacteriocin by the LAB isolates. Sensitive fluorescence-based assays employing specific probes indicated the comparative potencies of the bacteriocin and clearly revealed the membrane-targeted anti-listerial activity of the purified bacteriocin produced by selected LAB isolates. The food application potential of plantaricin A produced by a native isolate Lactobacillus plantarum CRA52 was evidenced as the bacteriocin suppressed the growth of Listeria monocytogenes Scott A inoculated in paneer samples that were stored at 8 °C for 5 days.
authors.affiliation: Department of Biotechnology, Indian Institute of Technology Guwahati, Guwahati, 781 039, Assam, India.
authors.forename: Atul Kumar
authors.initials: AK
authors.lastname: Singh
authors.affiliation: Department of Biotechnology, Indian Institute of Technology Guwahati, Guwahati, 781 039, Assam, India.
authors.forename: Sandipan
authors.initials: S
authors.lastname: Mukherjee
authors.affiliation: Department of Biotechnology, Indian Institute of Technology Guwahati, Guwahati, 781 039, Assam, India.
authors.forename: Manab Deb
authors.initials: MD
authors.lastname: Adhikari
authors.affiliation: Department of Biotechnology, Indian Institute of Technology Guwahati, Guwahati, 781 039, Assam, India. aramesh@iitg.ernet.in.
authors.forename: Aiyagari
authors.initials: A
authors.lastname: Ramesh
keywords: Bacteriocin; Lactic acid bacteria; Listeria monocytogenes; Membrane damage; Paneer