Identification of an anti-listerial domain from Pediococcus pentosaceus T1 derived from Kimchi, a traditional fermented vegetable

The aim of this study was to isolate and identify anti-listerial substances produced by lactic acid bacteria in Kimchi, a traditional fermented vegetable. The Pediococcus pentosaceus T1 strain, which has an antimicrobial effect on Listeria monocytogenes, was isolated from Kimchi using 16S rRNA analysis. A crude culture of P.pentosaceus T1 demonstrated anti-listerial activity that was unaltered by pH changes in the range of 4-8 and temperatures between 80 and 110°C. However, anti-listerial activity of P.pentosaceus T1 was abolished upon protease- and lipase-treatments, suggesting that the active substances were composed of peptides and lipids. Amylase, however, showed very little change in activity when compared to the control. Passage of the culture supernatant over Sep-Pak C18 cartridges showed that the anti-listerial activity could be traced to a component in the water-soluble fraction. Further purification of the activity was carried out using a series of steps that included ammonium sulfate precipitation, desalting, ion exchange chromatography, and ultrafiltration of the supernatants of P.pentosaceus cultures. The active fraction showed the presence of a 23-kDa protein, as visualized by SDS-PAGE followed by coomassie blue staining. Liquid chromatography (LC) and mass spectrometry (MS) analyses of the protein confirmed the presence of a Lysin motif (LysM) domain, which is known to be present in bacterial peptidoglycan hydrolases. In this study, we have demonstrated that Kimchi-derived P.pentosaceus shows an anti-listerial activity, and identified the active moiety as a LysM domain in a 23-kDa protein.