Purification and characterization of a bacteriocin produced by Lactococcuslactis subsp lactis H-559 isolated from kimchi

Lactic acid bacteria were isolated from kimchi and screened for bacteriocin production. Strain H-559, identified as Lactococcus lactis subsp. lactis, exhibited the strongest antibacterial activity among them and was active ag ainst pathogenic bacteria such as Listeria monocytogenes and Staphylococcus aureus as well as many lactic acid bacteria. The antimicrobial substance p roduced by L. lactis subsp. lactis H-559 was inactivated by alpha-chymotryp sin, and protease type IX and XIV and was confirmed to be a bacteriocin. Th e bacteriocin activity was stable from pH 2.0-11.0 and up to 10 min heating at 100 degrees C. The bacteriocin was sequentially purified by ammonium su lfate precipitation, ion-exchange chromatography, and reversed-phase high-p erformance liquid chromatography (HPLC). Its molecular weight was determine d to be 3343.7 Da by MALDI-mass spectrometry, Isoleucine was detected as th e first N-terminal amino acid residue but the remaining amino acid sequence could not be determined by the Edman degradation method. It was different from other bacteriocins in terms of pH stability, molecular weight, amino a cid composition, and the partial amino acid sequences of peptides obtained by acid hydrolysis.