Evaluation of antimicrobial and proteolytic activity of enterococci isolated from fermented products

A collection of 26 enterococci isolated from dairy and meat products were tested for antimicrobial and proteolytic activity. Enterococcus faecium and E. faecalis were the most frequent species among tested enterococci, and 11 isolates produced antimicrobial compounds. Results revealed that 10 out of 11 enterococci synthesized enterocins showing antimicrobial activity against food-born pathogen such as Listeria monocytogenes and Staphylococcus aureus. The broadest spectrum of antimicrobial activity was detected in E. faecalis BGPT1-10P and BGPT1-78. E. faecalis BG221 showed antimicrobial activity that was not related to production of enterocin, H2O2 or organic acid. Twenty-five enterococci showed strong or moderate proteolytic activity towards beta-casein. Two isolates, BGPT1-10P and BGPT1-78, showed the most intense hydrolysis of alpha(s1)-, beta-, kappa-casein fractions, total casein as well as gelatin. Extracellular BGPT1-10P and BGPT1-78 proteinases have a molecular mass of about 29 kDa. Bacteriocin production and proteinase activity of natural isolates of enterococci may be of technological interest in dairy and meat-fermented products