Bacterial Fermentation of Nicotinic Acid

The ability of certain bacterial species to oxidize nicotinic acid was first reported by Allison (1) who used suspensions of bacteria isolated by Dubos and Miller (2). Koser and Baird (3) later isolated strains of Pseudomonas jluorescens which grew on a synthetic medium in which nicotinic acid was the sole carbon source. These strains did not attack isonicotinic acid, picolinic acid, or pyridine. Nichol and Michaelis (4) then demonstrated that the destruction of nicotinic acid by this organism was an oxidative process accompanied by an uptake of oxygen. Most recently Hughes (5), using the same organism, has presented evidence that 6-hydroxynicotinic acid is an intermediate in oxidative degradation of nicotinic acid. There has been no previous study of the degradation of nicotinic acid by anaerobic bacteria. By means of the enrichment culture technique an anaerobic spore-forming rod has been isolated which ferments nicotinic acid and which utilizes high concentrations of this compound for its growth. The dependence on a high concentration of nicotinic acid for anaerobic growth suggests that the compound may serve as an energy, carbon, or nitrogen source for growth. This report presents evidence showing that the fermentation of nicotinic acid results in the formation of acetate, propionate, ammonia, and COS. The anaerobic bacteria reported here may provide a system for the investigation of the mechanism of the direct utilization of the energy of nicotinic acid and of the nature of the intermediates involved. A preliminary report (6) of this study has been published.