Potential Probiotic Enterococcus faecium OV3-6 and Its Bioactive Peptide as Alternative Bio-Preservation

Abstract

Probiotic <i>Enterococcus faecium</i> OV3-6 and its secreted active peptide were characterized and investigated. The strain survived in simulated gastric and small intestinal conditions at 88.16% and 94.33%, respectively. The safety assessment revealed that the strain was shown α-hemolysis and susceptible to most clinically relevant antibiotics, but intermediate sensitivity to erythromycin and kanamycin was found. It does not harbor any virulence genes except for the <i>efaA_fm</i> gene. Both of its living cells and the cell-free supernatants (CFS) of the strain significantly reduced the adhesion of <i>E. coli</i> and <i>S. Typhi</i> on Caco-2 cells. The strain can regulate the secretion of pro and inflammatory cytokines, IL-6 and IL-12 and induce the secretion of anti-inflammatory IL-10 of the Caco-2 cell. The strain can prevent the growth of Gram-positive strains belonging to the genera <i>Bacillus</i>, <i>Carnobacterium</i>, <i>Listeria</i>, and <i>Staphylococcus</i>. It also presented the <i>entP</i> gene that involves the production of bacteriocin named enterocin P. The antimicrobial peptide was matched 40% with 50S ribosomal proteins L29 (7.325 kDa), as revealed by LC-MS/MS. This active peptide exhibits heat stability, is stable over a wide pH range of 2-10, and maintains its activity at -20 and 4 °C for 12 weeks of storage. Altogether, <i>E. faecium</i> OV3-6 thus has potential for consideration as a probiotic and bio-preservative for applied use as a fermented food starter culture and in functional food or feed industries.