Isolation of Lactic Acid Bacteria with High Biological Activity from Local Fermented Dairy Products

The thirty-two strains of lactic acid bacteria were isolated from the Mongolian traditional fermented dairy products, among them 25 strains show antimicrobial activity against test microorganisms including Escherichia coli , Staphylococcus aureus , Enterococcus faecalis , Pseudom о nas aeruginosa . Protease sensitivity assay demonstrated that the antimicrobial substances produced by isolates А 23, Т 2 are bacteriocins as their antibacterial activities were eliminated completely after treatment with protease. Identi fi cation of bacteria is being carried out. Among the isolates 22 strains show protease enzyme producing activity. The selected strains isolated from mare’s fermented milk (airag or kumis) and yoghurt (tarag) show the speci fi c protease activity from 7.9 μ g/ml to 11.9 μ g/ml. The strain T2, isolated from yoghurt exhibited the highest proteolytic activity