Diversity of bacteriocinogenic lactic acid bacteria isolated from boza, a cereal-based fermented beverage from Bulgaria

The aim of this study was to isolate new bacteriocin-producing lactic acid bacteria from boza and to compare the bacteriocins with those previously described for strains isolated from the same niche. Five bacteriocin-producing lactic acid bacteria (Lactobacillus plantarum ST69BZ, Enterococcus faecium ST62BZ and Leuconostoc lactis ST63BZ, ST611BZ and ST612BZ) were isolated from boza. The bacteriocins of all five isolates inhibited the growth of Enterococcus spp., Escherichia coli, Klebsiella pneumoniae, Lactobacillus spp., Lactococcus lactis subsp. lactis, Listeria spp., Pseudomonas aerouginosa, Staphylococcus spp. and Streptococcus caprinus. The mode of activity of bacteriocins ST69BZ, ST62BZ, ST63BZ, ST611BZ and ST612BZ is bactericidal, as determined against E. faecium HKLHS and L. sakei DSM 20017, respectively. Two of the five studied bacteriocinogenic strains (ST69BZ and ST612BZ) exhibit activity against some fungal cultures. A synergetic effect between bacteriocins ST69BZ, ST62BZ, ST63BZ, ST611BZ and ST612BZ and ciprofloxacin were registered.