Weissella cibaria KS5가 생산하는 bacteriocin의 물리화학적인 안정성 평가

초록

This study aimed to identify bacteriocins that maintain antibacterial efficacy at neutral pH among strains with strong lactic acid production. Initially, screening for high lactic acid production ability was conducted on 71 lactic acid bacteria strains using 0.1% Congo Red. Among these, seven strains with higher acid production were selected. Weissella cibaria KS5 was ultimately selected based on its antimicrobial activity at a neutral pH. The antibacterial activity of W. cibaria KS5 peaked at 36 hr. Its antibacterial activity was excellent in the acidic range, but sharply decreased at pH 7.0 and reached a minimum at pH 9.0. However, some antibacterial activity increased under alkaline conditions. The KS5 bacteriocin was found to be very stable below 80°C, but showed a rapid decrease in antibacterial activity above this temperature. As the antibacterial activity was not reduced in the presence of proteinase K, it is presumed that bacteriocin consists of secondary metabolites or modified amino acids. Fractionation based on molecular weight revealed that the most of the KS5 bacteriocin was below 3 kDa. Thus, we propose that the major bacteriocin produced by W. cibaria KS5 hold significant industrial value as a metabolite under 3 kDa that maintains stability against heat, pH, acid, and bile salts.

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