Metabolism of raffinose has been examined in experiments with the growing culture and washed cells of Gluconobacter oxydans L-1. Degradtion of the trisaccharide was found to be catalyzed by levansucrase, levan being synthesized, and melibiose and small quantitites of fructose being liberated in the reaction. Melibiose is not hydrolyzed and is not used by the bacterium as a source of carbon, but is oxidized to melibionic acid. Fructose is assimilated by the bacterium in constructive metabolism, being oxidized to gluconic, 2-ketogluconic acids and 5-ketofructose.