In this experiment, strain T of ruminal treponemes was studied regarding the ability to utilize β-2,6- and β-2,1-fructose polymers as well as sucrose and fructose. Bacteria were able to grow on laboratory-prepared timothy grass fructan and commercial inulin, but not on sucrose or fructose. The optical density of cultures growing on inulin and timothy grass fructan was 0.5 and 1.1 absorbance units, respectively. Bacteria utilized up to 80% of the timothy grass fructan and only 30% of inulin during a 24 h incubation period. It was found that bacteria utilized only the β-2,1-inulooligosaccharides present in the commercial inulin while the long-chain polysaccharides remained undigested. Enzymatic studies showed that the bacterial cell-free extract degraded the timothy grass fructan, inulin and sucrose, releasing 13.4-19.1, 11.1-14.9 and 42.4-52.9 μM fructose/mg protein/h, respectively. It is suggested that enzymes involved in the degradation of fructose polymers could form a complex of which the enzyme specifically digesting the timothy grass fructan is associated with the outer membrane and acts on cell surfaces, while unspecific β-fructofuranosidase occupies an intracellular space and digests only the carbohydrates inside the bacterial cells. It is also suggested that such a localization of enzymes could be responsible for the inability of bacteria to utilize long-chain inulin. It is supposed that the examined bacteria are lacking in mechanism(s) transporting sucrose and fructose from the growth medium to the intracellular space of these microorganisms.