title: Biomineralization of 3-nitrotoluene by Diaphorobacter species.
abstract: Three bacterial strains utilizing 3-nitrotoluene (3-NT) as a sole source of carbon, nitrogen and energy were isolated from an industrial wastewater treatment plant. Biochemical tests and 16S rDNA sequence analysis revealed that the isolated strains belonged to Diaphorobacter sp. Detailed studies were carried out with Diaphorobacter sp. strain DS2. Degradation of 3-NT by Diaphorobacter sp. strain DS2 was accompanied by the release of nitrite in the culture broth with increase in biomass. Total organic carbon analysis confirmed the extensive mineralization of 3-NT. The strain could degrade 3-methylcatechol, 4-methylcatechol and catechol easily suggesting that the degradation pathway could involve these as possible intermediates. Successful PCR amplification of the oxygenase large subunit and the presence of high activity for catechol 2,3-dioxygenase in the crude cell lysate further confirmed that the degradation of 3-NT occurred through (methyl)catechol intermediates in strain DS2. The strain DS2 was found to degrade other isomers of mononitrotoluene (2-NT and 4-NT) and nitrobenzene as well.
authors.affiliation: Department of Chemistry, Indian Institute of Technology, Kanpur, 208016, India.
authors.forename: Deepak
authors.initials: D
authors.lastname: Singh
authors.forename: Gurunath
authors.initials: G
authors.lastname: Ramanathan
mesh_terms: D001673:Biodegradation, Environmental; D018533:Biomass; D050557:Catechol 2,3-Dioxygenase / Q000378:metabolism; D042621:Comamonadaceae / Q000201:enzymology / Q000302:isolation & purification / Q000378:metabolism*; D004269:DNA, Bacterial / Q000378:metabolism; D004587:Electrophoresis, Agar Gel; D008903:Minerals / Q000378:metabolism*; D008969:Molecular Sequence Data; D009573:Nitrites / Q000378:metabolism; D009578:Nitrobenzenes / Q000378:metabolism; D010802:Phylogeny; D010957:Plasmids / Q000378:metabolism; D021122:Protein Subunits / Q000378:metabolism; D014050:Toluene / Q000031:analogs & derivatives* / Q000378:metabolism
chemical_list: D004269:DNA, Bacterial; D008903:Minerals; D009573:Nitrites; D009578:Nitrobenzenes; D021122:Protein Subunits; C029956:3-nitrotoluene; D014050:Toluene; C029955:2-nitrotoluene; C036077:nitrobenzene; C017572:4-nitrotoluene; D050557:Catechol 2,3-Dioxygenase