Partial characterization of bacteriocins produced by four lactic acid bacteria isolated from regional South African barley beer

Abstract

Lactobacillus paracasei subsp. paracasei ST11BR, Lactobacillus plantarum ST13BR, Lactobacillus pentosus ST151BR and Lactococcus lactis subsp. lactis ST34BR produce bacteriocins active against Lactobacillus casei, Lactobacillus sakei, Pseudomonas aeruginosa, Escherichia coli and Enterococcus faecalis. Bacteriocin activity was not recorded after treating of the cells with NaCl at low pH, suggesting that the peptides do not adhere to the cell surface. The bacteriocins were resistant to treatment with SDS, Tween 20, Tween 80, urea and EDTA. Treatment with Triton X-100 reduced the activity of the four bacteriocins. Triton X-114 had no effect on bacteriocin ST11BR, bacteriocin ST151BR and bacteriocin ST34BR. Bacteriocin ST13BR lost all its activity after treatment with Triton X-114. The molecular size of bacteriocins ST11BR, ST13BR, ST151BR and ST34BR are 3.2 kDa, 10 kDa, 3.0 kDa and 2.9 kDa, respectively. All four bacteriocins are produced during stationary growth. No plasmids were isolated, suggesting that the genes encoding production of these bacteriocins are located on the genome.Articl

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