Molecular characterization of selected clostridial strains isolated from cheeses

The study was focused on molecular characterization of 42 clostridial strains. DNA was isolated by fenol-chloroform extraction procedure and precipitated with ethanol. After DNA isolation, PCR amplifications with specific primer sets were used for genus and species identification. Finally 19 strains were clasified as Clostridium tyrobutyricum and 3 strains were clasified as Clostridium butyricum. Presence of hydrogenase gene hydA was tested by PCR amplification using specific primer set HGf and HGr. Presence of hydrogenase gene was detected within 21 strains. (GTG)5 primer (rep-PCR) and Pr1 and Pr6 primers (RAPD) were used for differentiation of clostridial strains. Next, the cultivation of Clostridium tyrobutyricum S5 was studied under different conditions. The cultivation was carried out in liquid Reinforced Clostridial Medium (RCM) with lactose and cheese whey instead of glucose under anaerobe conditions. Growth was observed at laboratory temperature (20 to 23 °C) and at 37 °C, pH values ranging from 4.0 to 8.0 with 0.5 unit