Pentocin 31-1, an anti-Listeria bacteriocin produced by Lactobacillus pentosus 31-1 isolated from Xuan-Wei Ham, a traditional China fermented meat product

Strain 31-1 was isolated from the traditional China fermented Xuan-Wei Ham and identified as Lactobacillus pentosus 31-1, produced pentocin 31-1 at 640 arbitrary units (AU)/ml in MRS broth in the early stationary phase (i.e. after 24 h). After concentration by ammonium sulfate precipitation, followed by separation in SP-Sepharose fast flow cation exchange chromatography, the bacteriocin had a molecular weight of approximately 14.2 kDa when analyzed by Tricine–SDS–PAGE. Pentocin 31-1 showed a wide range of antimicrobial activity against Listeria spp., Staphylococcus spp., Bacillus spp., Lactobacillus spp., Streptococcus spp., Pediococcus spp. and Escherichia spp. All Listeria strains tested, including Listeria monocytogenes, were highly sensitive to the bacteriocin. Pentocin 31-1 was heat stable, pH resistant and protease sensitive. Tween 80, tween 20 and urea did not decrease the activity, however, SDS induced 75% activity loss. The bacteriocin exerted a bactericidal action on sensitive cells of L. monocytogenes 54002 in TSYE broth. It did not adhere to the surface of the producer cells. And 50% bacteriocin adsorption to the surface of L. monocytogenes 54002 cells was found at pH 6.0–7.5, whereas no bacteriocin adsorption was detected at pH 5.0–5.5.