Bacterial Oxidation of Lactose and Melibiose

DURING an investigation of bacteria isolated from blocks of whale meat, two distinct strains of paracolon bacteria (Bl x , urease-positive; and C 6, urease-negative) were obtained, the sugar metabolism of which was interesting. Tested in the normal way with Durham tubes, these organisms produced acid from lactose within 5–12 days at 30° C. and were accordingly recorded as late lactose fermenters. Tested by Hugh and Leifson's 1 method, both strains fermented cellobiose, maltose, sucrose, trehalose, galactose, glucose, mannitol and sorbitol, producing acid and gas anaerobically within 48 hr. at 30° C. Lactose, melibiose and glycerol, however, were not fermented but oxidized, that is, acid was produced from these sugars within 48 hr. under aerobic conditions only.