title: Biodegradation of 3-nitrotoluene by Rhodococcus sp. strain ZWL3NT.
abstract: A pure bacterial culture was isolated by its ability to utilize 3-nitrotoluene (3NT) as the sole source of carbon, nitrogen, and energy for growth. Analysis of its 16S rRNA gene showed that the organism (strain ZWL3NT) belongs to the genus Rhodococcus. A rapid disappearance of 3NT with concomitant release of nitrite was observed when strain ZWL3NT was grown on 3NT. The isolate also grew on 2-nitrotoluene, 3-methylcatechol and catechol. Two metabolites, 3-methylcatechol and 2-methyl-cis,cis-muconate, in the reaction mixture were detected after incubation of cells of strain ZWL3NT with 3NT. Enzyme assays showed the presence of both catechol 1,2-dioxygenase and catechol 2,3-dioxygenase in strain ZWL3NT. In addition, a catechol degradation gene cluster (catRABC cluster) for catechol ortho-cleavage pathway was cloned from this strain and cell extracts of Escherichia coli expressing CatA and CatB exhibited catechol 1,2-dioxygenase activity and cis,cis-muconate cycloisomerase activity, respectively. These experimental evidences suggest a novel pathway for 3NT degradation with 3-methylcatechol as a key metabolite by Rhodococcus sp. strain ZWL3NT.
authors.affiliation: Key Laboratory of Agricultural and Environmental Microbiology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China.
authors.forename: Xiao-Jun
authors.initials: XJ
authors.lastname: Tian
authors.forename: Xiao-Yang
authors.initials: XY
authors.lastname: Liu
authors.forename: Hong
authors.initials: H
authors.lastname: Liu
authors.forename: Shu-Jun
authors.initials: SJ
authors.lastname: Wang
authors.forename: Ning-Yi
authors.initials: NY
authors.lastname: Zhou
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001673:Biodegradation, Environmental; D050548:Catechol 1,2-Dioxygenase / Q000235:genetics / Q000378:metabolism; D050557:Catechol 2,3-Dioxygenase / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D012240:Rhodococcus / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D014050:Toluene / Q000031:analogs & derivatives* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; C029956:3-nitrotoluene; D014050:Toluene; D050548:Catechol 1,2-Dioxygenase; D050557:Catechol 2,3-Dioxygenase