Anaerobic degradation of 2-aminobenzoate (anthranilic acid) by denitrifying bacteria

In the presence of oxygen many aminoaromatic compounds polymerize to form recalcitrant macromolecules. To circumvent undesirable oxidation reactions, the anaerobic biodegradation of a simple member of this class of compounds was investigated. Two strains of bacteria were isolated which degrade 2-aminobenzoate anaerobically under denitrifying conditions, with nitrate as the terminal electron acceptor. Both organisms, which were assigned to the genus Pseudomonas, oxidized 2-aminobenzoate completely to CO2 and NH4+. Nitrate was reduced to nitrite. When nitrate was deplete from the growth medium the accumulated nitrite was reduced to nitrogen. The results establish a model system for the anaerobic, rapid, and complete oxidation of an aminoaromatic compound.