DETECTION AND CHARACTERIZATION OF A NOVEL ANTIBACTERIAL SUBSTANCE PRODUCED BY A LACTOBACILLUS-DELBRUECKII STRAIN-1043

A novel antibacterial substance produced by a strain isolated from Bul garian yellow cheese was characterized. The producer strain was identi fied by molecular typing to belong to the species Lactobacillus delbru eckii,which is a rare producer of bacteriocins. The inhibitory agent w as heat stable and active against lactic acid bacteria species and sev eral food-borne pathogens: Listeria monocytogenes, Staphylococcus aure us, Enterococcus faecalis, Escherichia coli, Yersinia enterocolitica a nd Y. pseudotuberculosis. Its sensitivity to amylolitic enzymes and li pase suggested that a lipid and carbohydrate moiety could be important for the activity. The amino acid content of the purified bacteriocin aias estimated to 29 amino acids. The bacteriocin was shown to be smal l (3.6-6 kDa) by three different methods: HPLC gel-filtration, SDS-PAG E and amino acid contents.