Antibacterial Activity and In vitro Probiotic Properties of Lactococcus lactis Isolated from Sea Bass (Dicentrarchus labrax)
Abstract
This study aimed to screen the antibacterial effect of Lactococcus lactis against selected pathogens and to characterize its probiotic properties in vitro. The whole-cell product and cell-free supernatant of L. lactis were tested and the antibacterial effect of the whole-cell compound was found to be greater than that of the cell-free supernatant. L. lactis exhibited the greatest inhibitory effect against A. veronii from which it was isolated from the same environment. L. lactis showed observable growth at 4-37 °C, 1-4% NaCl, 0.3% ox gall and pH 2-3. The cells had 89.3 % hydrophobicity. Of the 19 enzymes tested in the API-ZYM system, only 7 were evident for the strain. L. lactis was resistant to streptomycin and sulfadiazine but was susceptible to 7 other antibiotics commonly used in aquaculture. It was γ-hemolytic. The results demonstrated that L. lactis exhibited probiotic properties such as being able to survive in a wide temperature and salinity range, growing in acidic and bile salt environments, and producing enzymes that can support digestion. According to these findings, L. lactis may have the potential to be used as a probiotic supplement in aquaculture.
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References
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