A collection of 57 enterococcal isolates from different origin (including river, treatment plant, spring and garbage water, soil, animal, and vegetables from Aydın) was screened for the production of bacteriocins. Enterococci were identified at species levels as Enterococcus faecium (34), E. hirae (6), E. casseliflavus (4), E. durans (4), E. faecalis (4), E. mundtii (3) and E. avium (2). Of the 57 isolates 40 of them inhibited the growth of at least one indicator bacterium. Based on our PCR results 54 strains possesed enterocin genes. The genes of entA and entB were the most frequently detected structural genes among the PCR positive strains (54 and 53 strains, respectively) and the entB gene was always associated with entA gene. The highest combination of enterocin genes (24 of 54 strains) detected was entA, entB, entP and entL50A/B. The enterocins AS-48 and CylL LS genes were not found. Three enterococcal isolates, 2 E. faecium and 1 E. hirae were not harbour any of tested enterocin genes. No correlation between the presence of enterocin structural genes and the origin of the strain was detected, also no relationship seemed to exist between the tested enterocin genes and the activity spectra of isolates. Genes encoding bacteriocins are widely disseminated among enterocci from different origin and more studies should be done for evaluate industrial potential of bacteriocins.

A total of 201 thermophilic bacteria isolated from various thermal spring, mud and soil were tested for their antibacterial activity. Among the mostly active isolates, Geobacillus toebii HBB-247 was further examined. Bacteriocin-like inhibitory substance (BLIS) produced by strain HBB-247 was found to be stable up to 60°C, sensitive to proteolytic enzymes and effective against Enterococcus faecalis, Listeria sp., E. avium, Clostridium pasteurianum, Cellulomonas fimi and some thermophilic strains isolated and identified in this study. As a result of Tricine-SDS-PAGE molecular weight of BLIS was estimated about 38 kDa. Production studies showed that G. toebii HBB-247 starts to produce antibacterial substance at early logarithmic phase of growth and maximum production was detected at the end of the logarithmic phase.

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