Microbial mineralization of ring-substituted anilines through an ortho-cleavage pathway.
Moraxella sp. strain G is able to utilize as sole source of carbon and nitrogen aniline, 4-fluoroaniline, 2-chloroaniline, 3-chloroaniline, 4-chloroaniline (PCA), and 4-bromoaniline but not 4-iodoaniline, 4-methylaniline, 4-methoxyaniline, or 3,4-dichloroaniline. The generation time on PCA was 6 h. The pathway for the degradation of PCA was investigated by analysis of catabolic intermediates and enzyme activities. Mutants of strain G were isolated to enhance the accumulation of specific pathway intermediates. PCA was converted by an aniline oxygenase to 4-chlorocatechol, which in turn was degraded via a modified ortho-cleavage pathway. Synthesis of the aniline oxygenase was inducible by various anilines. This enzyme exhibited a broad substrate specificity. Its specific activity towards substituted anilines seemed to be correlated more with the size than with the electron-withdrawing effect of the substituent and was very low towards anilines having substituents larger than iodine or a methyl group. The initial enzyme of the modified ortho-cleavage pathway, catechol 1,2-dioxygenase, had similar characteristics to those of corresponding enzymes of pathways for the degradation of chlorobenzoic acid and chlorophenol, that is, a broad substrate specificity and high activity towards chlorinated and methylated catechols.
D000814:Aniline Compounds / Q000096:biosynthesis / Q000378:metabolism*; D001673:Biodegradation, Environmental; D009016:Moraxella / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D009154:Mutation; D010105:Oxygenases / Q000032:analysis / Q000378:metabolism*; D013379:Substrate Specificity; D013997:Time Factors
D000814:Aniline Compounds; D010105:Oxygenases; C046396:aniline oxygenase; C004658:4-chloroaniline