A bacterial strain which utilizes 3-methylquinoline as sole source of carbon, nitrogen and energy was isolated from activated sludge. On the basis of its morphological and physiological characteristics, this isolate was classified as Comamonas testosteroni. Four metabolites of 3-methylquinoline degradation were isolated from the culture supernatant and identified as 3-methyl-2-oxo-1,2-dihydroquinoline, 6-hydroxy-3-methyl-2-oxo-1,2-dihydroquinoline, 5,6-dihydroxy-3-methyl-2-oxo-1,2-dihydroquinoline and 2,5,6-trihydroxy-3-methylpyridine. Based on these results, a degradation pathway for 3-methylquinoline is proposed.
