SCREENING OF ANTIMICROBIAL ACTIVITIES AMONG BULGARIAN LACTOBACILLI STRAINS
Zdravka Sholeva*, Stanka Stefanova and Valentina Chipeva
National Bank for Industrial Microorganisms and Cell Cultures,
1113 Sofia, P.O.Box 239, Bulgaria
Forty-six strains of genus Lactobacillus from the collection of the National Bank for Industrial Microorganisms and Cell Cultures (NBIMCC) were screened by the use of the agar drop diffusion test, for antibacterial activity against nine test-microorganisms. Lactobacillus casei 300 exhibited activity against eight lactic acid bacteria and one yeast strains. The substance with antibacterial activity, produced by the NBIMCC 300 strain, was inactivated by proteolytic enzymes and possessed thermostability when heated to 80oC. This gave us a reason to conclude that this substance belonged to the bacteriocins' group.