Aerobic biodegradation of 3-aminobenzoate by gram-negative bacteria involves intermediate formation of 5-aminosalicylate as ring-cleavage substrate.

The aerobic metabolism of 3-aminobenzoate by bacteria was studied. Bacterial strains degrading 3-aminobenzoate were obtained by enrichment with 3-aminobenzoate (strain Ia3) or 5-aminosalicylate (strains BN9 and 5AS1). During growth with 3-aminobenzoate, strain Ia3 and strain 5AS1 transiently accumulated 5-aminosalicylate in the culture broth. In the presence of inhibitors of 5-aminosalicylate 1,2-dioxygenase, resting cells of all three strains converted 3-aminobenzoate to stoichiometric amounts of 5-aminosalicylate. 5-Aminosalicylate 1,2-dioxygenase activity was induced in all strains after growth with 3-aminobenzoate or 5-aminosalicylate, but not after growth in complex media.