Evaluation of antimicrobial activity, probiotic properties and safety of wild strain Enterococcus faecium AQ71 isolated from Azerbaijani Motal cheese

The aims of this study were to characterize bacteriocin activity, some functional and probiotic properties, and to evaluate the safety of Enterococcus faecium AQ71 isolated from Azerbaijani Motal cheese. The studied strain inhibited the growth of selected tested LAB, Listeria monocytogenes and Bacillus cereus strains. PCR amplification with specific primers indicated that E. faecium AQ71 carry genes encoding enterocins P, L50A, L50B and A. Bacteriocin(s) produced by the studied strain was/were heat stable and active in a broad pH range. Triton X-20, Triton X-80, Triton X-100, β-mercaptoethanol, Na-EDTA, SDS and NaCl did not affect the antimicrobial activity of the strain. The cell free supernatants of the strain caused the lysis of cells of Lactobacillus brevis F145 and inhibited the growth of L. monocytogenes. E. faecium AQ71 was negative for the tested virulence factors and did not present multi-resistance to antibiotics. The strain was resistant to physiological concentrations of bile salts and showed good auto-aggregation ability as well as co-aggregation ability with L. monocytogenes. E. faecium AQ71 exhibited good esterase, esterase lipase, acid phosphatase and aminopeptidase activities.