Lacticin LC14, a New Bacteriocin Produced by Lactococcus lactis BMG6.14: Isolation, Purification and Partial Characterization

Samar      Lasta; Hadda      Ouzari; Nicolas      Andreotti; Ziad      Fajloun; Pascal      Mansuelle; Abdellatif      Boudabous; François      Sampieri; Jean      Marc Sabatier

Abstract

A new bacteriocin, lacticin LC14, produced by Lactococcus lactis BMG6.14, was isolated and characterized. It was purified to homogeneity from overnight broth culture by ammonium sulfate precipitation, Sep-Pak chromatography, and two steps of reversed-phase HPLC. Lacticin LC14 showed bactericidal-type antimicrobial activity against several lactic acid bacteria and pathogenic strains including Listeria monocytogenes. It was inactivated by proteinase K and pronase E, but was resistant to papain, lysozyme, lipase and catalase. Lacticin LC14 was heat resistant, stable over a wide range of pH (2-10) and after treatment by solvents and detergents. Its N-terminal end was found unreactive towards Edman sequencing. Based on MALDI-TOF mass spectrometry, its molecular mass was 3333.7 Da. LC14 amino acid composition revealed a high proportion of hydrophobic residues, but no modified ones. LC14 may be able to challenge other well known other bacteriocins in probiotic and therapeutic applications.

Keywords: Antimicrobial activity, Bacteriocin, Lactic acid bacteria, Lacticin LC14, Listeria monocytogenes, Lactococcus lactis subsp. lactis BMG6.14, ammonium sulfate precipitation, chromatography, chromatography, pathogenic strains, lysozyme, lipase and catalase, amino acid, hydrophobic residues