Propionibacterium shermanii CDB 10014 is able to grow even at high oxygen transfer rates (24.0 mmol O-2 l(-1) h(-1)), in contrast to reports in the specialised literature, where all Propionibacteria are considered oxygen-sensitive microorganisms. Propionic acid is the main product in anaerobiosis. The presence of oxygen in the system leads to an inhibition of propionic acid production while acetic acid formation is enhanced. Al high oxygen supply rates no propionic acid is produced and acetic acid is the main product. Lactic acid is also produced in reasonable quantities (2.7 g l(-1)). The growth rate (mu(max)) is higher in anaerobiosis (0.19 h(-1)) than in aerobiosis (0.12-0.15 h(-1)). The cell yield is higher in aerobiosis (0.18-0.22 g g(-1)) than in anaerobiosis (0.14 g g(-1)) suggesting the oxidative metabolism of glucose by Propionibacterium shermanii?ii CDB 10014. No corrinoid production was detected at oxygen transfer rates of more than 13.6 mmol l(-1) h(-1).