Fructooligosaccharides metabolism and effect on bacteriocin production in Lactobacillus strains isolated from ensiled corn and molasses

Fructo- (FOS) and galacto-oligosaccharides have been used to promote the growth of probiotics, mainly those from Lactobacillus genus. However, only few reports have evaluated the effect of prebiotics on bacteriocins activity and production. In this work, we characterized the effect of FOS supplementation on the growth, lactic and acetic acids production, and antimicrobial activity of crude extracts obtained from Lactobacillus strains isolated from ensiled corn and molasses. Seven out of 28 isolated Lactobacillus, belonging to Lactobacillus casei, Lactobacillus plantarum, and Lactobacillus brevis, showed antimicrobial activity against Listeria innocua. Among them, the strain L. plantarum LE5 showed antimicrobial activity against Listeria monocytogenes and Enteroccocus faecalis; while the L. plantarum LE27 strain showed antimicrobial effect against L. monocytogenes, E. faecalis, Escherichia coli and Salmonella enteritidis. This antimicrobial activity in most of the cases was obtained only after FOS supplementation. In summary, these results show the feasibility to increase the antimicrobial activity of Lactobacillus bacteriocins by supplementing the growth medium with FOS.

► We isolated 28 Lactobacillus strains from ensiled corn and molasses.
► Antimicrobial activity was improved in fructooligosaccharides supplemented medium.
► Two strains showed activity against Gram-negative and Gram-positive microorganisms.
► Consumption of low polymerization degree fructooligosaccharides was characterized.
► The proteinaceous origin of the antimicrobial agent was demonstrated.