Acetobacter pasteurianus NCIMB 11664 was selected for multigram-scale production of different aliphatic carboxylic acids through oxidation of the corresponding alcohols after screening different acetic acid bacteria. Continuous production was carried out using an air-lift reactor, with overall yields of 1-propionic, l-butyric, 2-methyl-1-butyric and 3-methyl-1-butyric acids ranging from 45 to 61 g dm(-3).