The aim of this study was to determine the capacity of two strains Lactobacillus to utilize lactose and its unabsorbable derivatives with prebiotic potential – lactulose and lactitol. The strains, named L. fermentumO and L. sakeiTA61, were cultivated in different modifi ed media, containing these saccharides. Effect on the growth of lactobacilli was studied, as well as the production of α- and β-galactosidases. Antibacterial activity was tested by the agar diffusion method. It was determined that the studied strains saved and showed very similar antibacterial activity, as grown on glucose against the test food patogens. The origin of carbon sources infl uenced activi ty of the studied enzymes, its maximum was found in the early log growth phase.