title: Degradation of phenanthrene by the rhizobacterium Ensifer meliloti.
abstract: The biodegradation of the polycyclic aromatic hydrocarbon phenantherene by the rhizobacterial strain Ensifer meliloti P221, isolated from the root zone of plant grown in PAH-contaminated soil was studied. Bacterial growth and phenanthrene degradation under the influence of root-exuded organic acids were also investigated. Analysis of the metabolites produced by the strain by using thin-layer chromatography, gas chromatography, high-pressure liquid chromatography, and mass-spectrometry revealed that phenanthrene is bioconverted via two parallel pathways. The first, major pathway is through terminal aromatic ring cleavage (presumably at the C3-C4 bond) producing benzocoumarin and 1-hydroxy-2-naphthoic acid, whose further degradation with the formation of salicylic acid is difficult or is very slow. The second pathway is through the oxidation of the central aromatic ring at the C9-C10 bond, producing 9,10-dihydro-9,10-dihydroxyphenanthrene, 9,10-phenanthrenequinone, and 2,2'-diphenic acid. This is the first time that the dioxygenation of phenanthrene at the C9 and C10 atoms, proven by identification of characteristic metabolites, has been reported for a bacterium of the Ensifer genus.
authors: Institute of Biochemistry and Physiology of Plants and Microorganisms, Russian Academy of Sciences, 13 Prospekt Entuziastov, 410049, Saratov, Russia, amuratova@yahoo.com.
authors: Anna
authors: A
authors: Muratova
authors: Natalya
authors: N
authors: Pozdnyakova
authors: Oleg
authors: O
authors: Makarov
authors: Mikhail
authors: M
authors: Baboshin
authors: Boris
authors: B
authors: Baskunov
authors: Nina
authors: N
authors: Myasoedova
authors: Ludmila
authors: L
authors: Golovleva
authors: Olga
authors: O
authors: Turkovskaya
mesh_terms: D001673:Biodegradation, Environmental; D001713:Biphenyl Compounds / Q000378:metabolism; D009284:Naphthols / Q000378:metabolism; D010616:Phenanthrenes / Q000378:metabolism*; D012231:Rhizobium / Q000378:metabolism*
chemical_list: D001713:Biphenyl Compounds; D009284:Naphthols; D010616:Phenanthrenes; C005399:9,10-phenanthrenequinone; C031181:phenanthrene; C039204:diphenic acid; C050175:1-hydroxy-2-naphthoic acid