Molybdenum-dependent degradation of nicotinic acid by Bacillus sp. DSM 2923

Growth of Bacillus sp. DSM 2923 on nicotinic acid in mineral medium was dependent on the concentration of sodium molybdate added. Addition of increasing amounts of tungstate to the medium resulted in an inhibition of growth on nicotinic acid or 6-hydroxynicotinic acid as sole source of carbon and energy. Chlorate-resistant mutants were isolated which were not able to degrade nicotinic acid and 6-hydroxynicotinic acid nor to reduce nitrate. Additionally, enzyme activities of nicotinic acid dehydrogenase and 6-hydroxynicotinic acid dehydrogenase increased with increasing concentrations of molybdate (10−8 to 10−6 M) added to the medium, and decreased with increasing amounts of tungstate (10−6 to 10−5 M) in the medium.