Identification and characterization of bacteriocin-producing lactic acid bacteria isolated from Kimchi

Lactic acid bacteria were isolated from Kimchi and screened for bacteriocin. A total of 99 strains showed antimicrobial activity when grown on solid media, yet only 10 showed antimicrobial activity in liquid media. Strain H-559, identified as Lactococcus lactis subsp. lactis, exhibited the strangest inhibitory activity and was active against pathogenic bacteria including Listeria monocytogenes, Staphylococcus aureus, and Bacillus cereus as well as other lactic acid bacteria. The antimicrobial substance produced by L. lactis subsp. lactis H-559 was confirmed to be a bacteriocin by the treatment of alpha-chymotrypsin, and protease type IX and XIV. The bacteriocin activity remained stable between pH 2.0 and pH 11.0 and during heating for 10 min at 100 degrees C. The bacteriocin production started in the exponential phase and stopped in the stationary phase. L. lactis subsp. lactis H-559 showed the highest bacteriocin activity at a culture temperature of 25 degrees C, and an inverse relationship between the bactriocin productivity and mean growth rate at different culture temperatures was observed. The mean growth rate and bacteriocin productivity of L. lactis subsp. lactis H-559 increased as the initial pH of the media increased.