Abstract:

A total of 38 strains of Lactococcus lactis ssp. lactis, were isolated from gastrointestinal tract of coastal fish: sardine (Sardina pilchardus) and bug (Boops boops). These isolates were tested for their ability to produce bacteriocins against Listeria innocua, Brochothrix thermophacta, Salmonella sp., Staphylococcus aureus, Bacillus cereus, Aeromonas hydrophila, Pseudomonas aeuroginosa Escherichia coli and Methycilin resistant Staphyococcus aureus. However characterization of the antimicrobial substances showed that only 04 of isolates produced antimicrobial activity in the neutralized cell-free supernatant treated with catalase against indicator strains. The compounds produced by the selected strains were fully or partially inactivated by some of the proteolytic enzymes (trypsine, α-chymotrypsin and proteinase K), which indicates their proteinaceous nature. The antimicrobial activity of crude supernatant fluid was stable after heating at 100 °C for 30 min and declined thereafter. It was also active over a wide pH range (4–8). Selected strains in this study might be valuable for practical application as source of bacteriocin, providing future scope for the biopreservation of seafood products

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