Purification and characterisation of the bacteriocin produced by Lactobacillus plantarum, isolated from Chinese pickle

Abstract

119 strains of lactic acid bacteria from Chinese pickle were tested for production of antimicrobial compounds (bacteriocins). Among them, strain C8 showed strongly antibacterial activity against Staphylococcus aureus ATCC 6538 and Escherichia coli ATCC 8739. Strain C8 was identified as Lactobacillus plantarum based on phenotypical, physiological tests and 16S rDNA identification. The antibacterial substance produced by strain C8 was sensitive to protease but not affected by lipase and amylase and designated as bacteriocin C8. Bacteriocin was purified by salting-out, dialysis and Sephadex G50 column chromatography. Based on SDS-PAGE, bacteriocin C8 was 16.5 kDa in size, which was different from that of other bacteriocins and it might be a novel bacteriocin. Bacteriocin C8 showed a wide range of antimicrobial activity especially as it inhibited some Gram-negative bacteria. This bacteriocin was heat resistant (20 min at 121°C) and stable in the pH range of 3 to 6.