4-Hydroxypyridine is an aromatic N-heterocycle, a significant class of industrial pollutants. 4-Hydroxypyridine and its derivatives inhibit photosystem II in plants (M. Soskic and A. Sabljic (1995) Pesticide Science (Croatia), 45(2), 133-41). 4-Hydroxypyridine is hazardous since it can irritate eyes, skin, lung, and gastrointestinal tract (MSDS for 4-Hydroxypyridine). Microbial utilization of hydroxypyridines is initiated by the hydroxylation of the aromatic structure, yielding di- and trihydroxylated intermediates of the ring (Watson et al., 1974a), followed by ring fission with the ultimate products being pyruvate, formate, and ammonia. Bacteria that degrade hydroxypyridine isomers are uncommon. Achromobacter sp. IN13 and Achromobacter sp. can hydroxylate 2-Hydroxypyridine and 3-Hydroxypyridine to the 2,3-diol (Houghton & Cain, 1972). As shown here, Agrobacterium sp. 35S hydroxylates 4-Hydroxypyridine to form 3,4-Dihydroxypyridine, which undergoes meta cleavage (Watson et al., 1974b).