title: Degradation of 2-methylaniline and chlorinated isomers of 2-methylaniline by Rhodococcus rhodochrous strain CTM.
abstract: Rhodococcus rhodochrous strain CTM co-metabolized 2-methylaniline and some of its chlorinated isomers in the presence of ethanol as additional carbon source. Degradation of 2-methylaniline proceeded via 3-methylcatechol, which was metabolized mainly by meta-cleavage. In the case of 3-chloro-2-methylaniline, however, only a small proportion (about 10%) was subjected to meta-cleavage; the chlorinated meta-cleavage product was accumulated in the culture fluid as a dead-end metabolite. In contrast, 4-chloro-2-methylaniline was degraded via ortho-cleavage exclusively. Enzyme assays showed the presence of catechol 1,2-dioxygenase and catechol 2,3-dioxygenase as inducible enzymes in strain CTM. Extended cultivation of strain CTM with 2-methylaniline and 3-chloro-2-methylaniline yielded mutants, including R. rhodochrous strain CTM2, that had lost catechol 2,3-dioxygenase activity; these mutants degraded the aromatic amines exclusively via the ortho-cleavage pathway. DNA hybridization experiments using a gene probe revealed the loss of the catechol 2,3-dioxygenase gene from strain CTM2.
authors.affiliation: Institut für Mikrobiologie, Universität Hohenheim, Stuttgart, FRG.
authors.forename: K
authors.initials: K
authors.lastname: Fuchs
authors.forename: A
authors.initials: A
authors.lastname: Schreiner
authors.forename: F
authors.initials: F
authors.lastname: Lingens
mesh_terms: D000814:Aniline Compounds / Q000378:metabolism*; D001565:Benzoates / Q000494:pharmacology; D019817:Benzoic Acid; D001673:Biodegradation, Environmental; D050548:Catechol 1,2-Dioxygenase; D050557:Catechol 2,3-Dioxygenase; D002713:Chlorine / Q000378:metabolism; D049308:Dioxygenases; D004586:Electrophoresis; D000431:Ethanol / Q000494:pharmacology; D015870:Gene Expression / Q000187:drug effects; D013058:Mass Spectrometry; D009154:Mutation / Q000235:genetics; D010105:Oxygenases / Q000378:metabolism; D012240:Rhodococcus / Q000187:drug effects / Q000378:metabolism*; D014052:Toluidines / Q000378:metabolism*
chemical_list: D000814:Aniline Compounds; D001565:Benzoates; D014052:Toluidines; C556393:p-chloro-o-toluidine hydrochloride; D000431:Ethanol; D002713:Chlorine; C071775:3-chloro-2-methylaniline; D019817:Benzoic Acid; C023622:2-toluidine; D010105:Oxygenases; D049308:Dioxygenases; D050548:Catechol 1,2-Dioxygenase; D050557:Catechol 2,3-Dioxygenase; C021313:methylaniline