Enzyme activities of lactic bacteria and streptococcus isolated from milk

The research of some enzyme characteristics and the inhibitory activity of pathogenic bacteria in food aimed to determine of lactic acid bacteria isolated from raw milk. Therefore, 74 isolates of lactic acid bacteria isolated was named from 30 raw milk samples. Species named; has been identified as 10 Lactobacillus delbrueckii ssp. lactis, 9 Lb. casei, 6 Lb. rhamnosus, 5 Lb. acidophilus, 5 Lb. coryniformis ssp. tourquens, 3 Lb. plantarum ssp. plantarum, 5 Leuconostoc mesenteroides ssp. mesenteroides, 3 Leu. mesenteroides ssp. dextranicum, 9 Pediococcus pentosaceus, 6 P. dextrinicus, 1 P. inopinatus, 1 P. acidilactici, 4 Streptococcus lactis, 1 S. cremoris, 2 Enterococcus faecalis, 1 E. faecium ve 3 Lactococcus lactis ssp. lactis. Lactic bacteria were investigated protease, lipase, elastase, α-amylase enzyme characteristics and hemolytic activities isolated from raw milk. Proteolytic activity was determined of 74 isolates in 70 isolates. 36 isolates (51.4%), weak (+), 34 isolates (48.6%), moderate (+ +) has shown proteolytic activity. The isolated from lactic bacteria, elastase enzyme characteristics appeared to function on the nutrient Agar in Elastin researched. Lactic bacteria investigated lipolytic activities on the Tributyrin Agar, Leu. mesenteroides ssp. dextranicum species detected zone diameter of 4 mm. The other strains was not observed zone diameter. α-Amylase enzyme activities were tested on Starch Agar. Lb. plantarum ssp. plantarum, Lb. casei, Lb. coryniformis ssp. tourquens, Pediococcus pentosaceus and Leu. mesenteroides ssp. dextranicum species demonstrated α-amylase (+) activity. Lactic bacteria were examined hemolytic activity on Colombia blood agar. S. lactis, Lactococcus lactis ssp. lactis ve Enterococcus faecium species demonstrated hemolytic (+) activity. On the other hand the other species was not observed hemolytic activity. Isolated from raw milk 17 different bacterial species taking from each strain was studied inhibitory effect. These bacteria was studied inhibitory effect in the well diffusion method Nutrient Agar and 0,2% glucose Nutrient Agar. While Lactic bacteria strains were showed on the S. aureus, L. Monocytogenes and S. typhimurium an inhibitory effect when they showed no effect on the E. coli and K. pneumoniae. In these conditions a larger zone diameters has been observed in glucose medium. In these circumstances the most greatest impact, Lb. delbrueckii ssp. lactis strain showed zone diameter 18mm on the L. monocytogenes and S. typhimurium. In these conditions a larger zone diameters has been observed in 0,2% glucose Nutrient Agar medium. All species studied lactic bacteria had no effect on E. coli and K. pneumoniae.