title: Benz[a]anthracene biotransformation and production of ring fission products by Sphingobium sp. strain KK22.
abstract: A soil bacterium, designated strain KK22, was isolated from a phenanthrene enrichment culture of a bacterial consortium that grew on diesel fuel, and it was found to biotransform the persistent environmental pollutant and high-molecular-weight polycyclic aromatic hydrocarbon (PAH) benz[a]anthracene. Nearly complete sequencing of the 16S rRNA gene of strain KK22 and phylogenetic analysis revealed that this organism is a new member of the genus Sphingobium. An 8-day time course study that consisted of whole-culture extractions followed by high-performance liquid chromatography (HPLC) analyses with fluorescence detection showed that 80 to 90% biodegradation of 2.5 mg liter(-1) benz[a]anthracene had occurred. Biodegradation assays where benz[a]anthracene was supplied in crystalline form (100 mg liter(-1)) confirmed biodegradation and showed that strain KK22 cells precultured on glucose were equally capable of benz[a]anthracene biotransformation when precultured on glucose plus phenanthrene. Analyses of organic extracts from benz[a]anthracene biodegradation by liquid chromatography negative electrospray ionization tandem mass spectrometry [LC/ESI(-)-MS/MS] revealed 10 products, including two o-hydroxypolyaromatic acids and two hydroxy-naphthoic acids. 1-Hydroxy-2- and 2-hydroxy-3-naphthoic acids were unambiguously identified, and this indicated that oxidation of the benz[a]anthracene molecule occurred via both the linear kata and angular kata ends of the molecule. Other two- and single-aromatic-ring metabolites were also documented, including 3-(2-carboxyvinyl)naphthalene-2-carboxylic acid and salicylic acid, and the proposed pathways for benz[a]anthracene biotransformation by a bacterium were extended.
authors.affiliation: Department of Life and Environmental System Science, Graduate School of Nanobiosciences, Yokohama City University, Kanazawa, Kanagawa, Yokohama, Japan.
authors.forename: Marie
authors.initials: M
authors.lastname: Kunihiro
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Ozeki
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Nogi
authors.forename: Natsuko
authors.initials: N
authors.lastname: Hamamura
authors.forename: Robert A
authors.initials: RA
authors.lastname: Kanaly
mesh_terms: D001551:Benz(a)Anthracenes / Q000378:metabolism*; D001711:Biotransformation; D002851:Chromatography, High Pressure Liquid; D008969:Molecular Sequence Data; D009930:Organic Chemicals; D012329:RNA, Bacterial / Q000235:genetics / Q000378:metabolism; D012336:RNA, Ribosomal, 16S / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D012989:Soil Pollutants / Q000378:metabolism*; D021241:Spectrometry, Mass, Electrospray Ionization; D042301:Sphingomonadaceae / Q000235:genetics* / Q000378:metabolism*; D053719:Tandem Mass Spectrometry
chemical_list: D001551:Benz(a)Anthracenes; D009930:Organic Chemicals; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D012989:Soil Pollutants; C042320:colony promoting activity; C030935:benz(a)anthracene