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Lactococcin K is a bacteriocin produced by Lactococcus lactis KCA 2386 isolated from traditionally fermented white kimchi. It was active against wide range of gram positive bacteria including food pathogens such as Enterococcus faecium, Listeria monocytogenes, and Staphylococcus aureus at the concentration higher than 50 AU/mL. Addition of 17 carbohydrates into the lactococcin K-containing medium showed significant synergism exerted at otherwise marginal concentration of lactococcin K. At 5% concentration, gluconate, sorbitol, fructose, and xylose showed strong synergistic effect on the antibacterial activity of lactococcin K against EE faeciwn, L monocytogenes, and S. aureus, while glucose, maltose, and sucrose showed synergistic effect against L monocytogenes, and S. aureus. However, this synergism exhibited species-specificity. Glucose showed more than 2 log cycle increase of antibacterial activity of lactococcin K against S. aureus whereas gluconate showed 4 log cycle increase of antibacterial activity of lactococcin K against L. monocytogenes.
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