Abstract: Enterococcus faecium SC-Y112 is a bacteriocin-producing lactic acid bacterium with broad-spectrum antibacterial properties. In order to better understand it, the in vitro prebiotic and safety properties of Enterococcus faecium SC-Y112 were explored through simulated gastrointestinal fluid tolerance, bile salt tolerance, antioxidant activity, hemolytic activity, gelatin liquefaction and harmful metabolite tests, as well as the evaluation of drug resistance and the virulence gene analysis of Enterococcus. The results showed that SC-Y112 had a strong tolerance to artificial gastrointestinal juice. The survival rate after 3 hours of exposure to it was 73.66% compared to 56.38% after 3 hours of exposure to 0.3 g/100 mL bile salt, and the total antioxidant activity of the 24 h fermentation supernatant was 35.21 U/mL. In addition, this strain could not produce biological amines, indoles, azoreductase or other harmful substances, caused no hemolysis, did not dissolve gelatin, did not carry the virulence genes of Enterococcus, and was sensitive to vancomycin. These results provide a scientific basis for further development and application of the strain.

Key words: Enterococcus faecium; prebiotic properties; safety properties; virulence genes