The Pathway of Nicotinic Acid Oxidation by a Bacillus Species.

Bacteria able to grow with nicotinic acid as a sole source of carbon and nitrogen have been isolated by a number of investigators (l-5). Hughes et al. (6-10) found that Pseudomonas jlzwrescens initiates degradation of nicotinic acid by a hydroxylation to form 6-hydroxynicotinic acid and established that the responsible enzyme is located in a cell wall membrane fraction. An initial hydroxylation in the 6-position was also reported by Harary (11,12) for a Clostridium species which ferments nicotinic acid, and by Behrman and Stanier (13) for a strain of P. jluorescens. The latter authors (13) showed that subsequent reactions, mediated by enzymes contained in the soluble fraction of disrupted cells, catalyze the oxidative decarboxylation of 6-hydroxynicotinic acid to 2,5-dihydroxypyridine and its cleavage to maleamic and formic acids. The former compound undergoes hydrolytic deamination to maleic acid, which is then isomerized to fumaric acid. This paper describes a different pathway of nicotinic acid oxidation utilized by a Bacillus species isolated from soil.