Utilization of agro-industrial byproducts for bacteriocin production using Enterococcus spp. strains isolated from Patagonian marine invertebrates

Abstract

This work's objective was to determine the antagonist activity of 11 Enterococcus spp. using industrial food wastes as a culture medium. The strains were isolated from invertebrates collected on the Argentinian Patagonia coast and selected by their high antibacterial activity. Phenotypic and genotypic techniques allowed identifying five E. hirae strains, five E. faecium strains, and one E. mundtii strain. The cell-free supernatants displayed inhibitory activity against most of the Gram-positive bacteria tested and Vibrio anguilarum. PCR amplification techniques detected the encoding genes of enterocin P in ten strains, mundtiicin KS in seven strains, enterocin B in six strains, hiracin JM79 in five strains, and enterocin A in three strains. The strains did not show gelatinase or hemolytic activities and were sensitive to gentamicin, kanamycin, streptomycin, tylosine, tetracycline, chloramphenicol and vancomycin. Cheese whey and hot trub derived from beer brewing were used alone or in combination to assay enterocin production. In all cases, the highest inhibitory activities were achieved when mixtures of both byproducts were used as growth medium. The results suggest that the selected strains can produce high levels of enterocins in a low-cost media composed of a mix of cheese whey and hot trub without additional supplementation with carbon or nitrogen sources.