title: Bacteriocin-Producing Lactic Acid Bacteria Isolated from Mangrove Forests in Southern Thailand as Potential Bio-Control Agents: Purification and Characterization of Bacteriocin Produced by Lactococcus lactis subsp. lactis KT2W2L.
abstract: The aim of this work was to purify and characterize the bacteriocin produced by Lactococcus lactis subsp. lactis KT2W2L previously isolated from mangrove forests in southern Thailand, in order to evaluate its potential as new food protective agent. The active peptide from the cell-free supernatant of this strain was purified in 4 steps: (1) precipitation with 70 % saturated ammonium sulfate, (2) elution on a reversed-phase cartridge using different concentrations of acetonitrile, (3) cation-exchange chromatography and (4) final purification by reversed-phase HPLC on a C8 column. The molecular mass of 3,329.5254 Da of the purified bacteriocin, determined by mass spectrometry, is nearly identical to that of peptide nisin Z. The activity of the purified bacteriocin was unaffected by pH (2.0-10.0), thermostable but was sensitive to proteolytic enzymes. The bacteriocin activity was stable after 8 weeks of storage at -20 °C and 7 weeks of storage at 4 °C, but decreased after 3 weeks of storage at 37 °C. It was stable when incubated for 1 month at 4 °C in 0-30 % NaCl. Inhibitory spectrum of this bacteriocin showed a wide range of activity against similar bacterial strains, food-spoilage and food-borne pathogens. L. lactis subsp. lactis KT2W2L was sensitive to kanamycin, penicillin and tetracycline but resistant to ampicillin, gentamicin and vancomycin. The fragment obtained after amplification of genomic DNA from L. lactis subsp. lactis KT2W2L, with specific primers for bacteriocin genes, presented 99 % homology to the nisin Z gene. PCR amplification demonstrated that L. lactis subsp. lactis KT2W2L does not harbor virulence genes cylA, cylB, efaAfs and esp. The bacteriocin and its producing strain may find application as bio-preservatives for reduction in food-spoilage and food-borne pathogens in food products.
authors.affiliation: Department of Industrial Biotechnology, Faculty of Agro-Industry, Prince of Songkla University, Hat Yai, 90112, Thailand.|UR 1268 Biopolymères Interactions Assemblages, Équipe Fonctions et Interactions des Protéines, INRA, 44316, Nantes Cedex 03, France.
authors.forename: Noraphat
authors.initials: N
authors.lastname: Hwanhlem
authors.affiliation: Department of Food and Experimental Nutrition, Faculty of Pharmaceutical Sciences, University of São Paulo, 580, Professor Lineu Prestes, 13 B, São Paulo, SP, 05508-000, Brazil.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Biscola
authors.affiliation: Faculty of Agriculture, Department of Dairy Sciences, Kafrelsheikh University, Kafrelsheikh, 33516, Egypt.
authors.forename: Shady
authors.initials: S
authors.lastname: El-Ghaish
authors.affiliation: LUNAM Université, Oniris, UMR 1014 Secalim, 44307, Nantes, France.|INRA, 44307, Nantes, France.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Jaffrès
authors.affiliation: LUNAM Université, Oniris, UMR 1014 Secalim, 44307, Nantes, France.|INRA, 44307, Nantes, France.
authors.forename: Xavier
authors.initials: X
authors.lastname: Dousset
authors.affiliation: UR 1268 Biopolymères Interactions Assemblages, Équipe Fonctions et Interactions des Protéines, INRA, 44316, Nantes Cedex 03, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Haertlé
authors.affiliation: Department of Industrial Biotechnology, Faculty of Agro-Industry, Prince of Songkla University, Hat Yai, 90112, Thailand.
authors.forename: Aran
authors.initials: A
authors.lastname: H-Kittikun
authors.affiliation: UR 1268 Biopolymères Interactions Assemblages, Équipe Fonctions et Interactions des Protéines, INRA, 44316, Nantes Cedex 03, France. chobert@nantes.inra.fr.
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Chobert
keywords: Bacteriocin; Lactococcus lactis; Nisin Z; Virulence genes