Characterisation of antilisterial bacteriocin-like substance produced by enterococcus mundtii

Abstract

The antilisterial activity of E. mundtii 1282 strain and its cell-free neutralised supernatant was observed against five persistent L. monocytogenes strains using the agar spot method. The enterococcal metabolite was consequently characterised as a proteinaceous substance - the bacteriocin-like substance, which was heat-stable at heating to 100°C for 30 min, stable at pH 2-12, and still active after eight-week long storage at 6°C and -20°C. The bacteriocin-like substance reached the highest activity of 6400 AU/ml after ten hours of cultivation of E. mundtii 1282 strain, when it was at the stationary phase of its growth. E. mundtii 1282 strain produced the bacteriocin-like substance: in BHI broth with pH 4-6, at the cultivation temperature 12-45°C, and in BHI broth with 1-6% (w/w) NaCl.