title: Phenanthrene biodegradation by halophilic Martelella sp. AD-3.
abstract: OBJECTIVE
  To investigate the phenanthrene-degrading abilities of the halophilic Martelella species AD-3 under different conditions and to propose a possible metabolic pathway.
  
  
  RESULTS
  Using HPLC and GC-MS analyses, the phenanthrene-degrading properties of the halophilic strain AD-3 and its metabolites were analysed. This isolate efficiently degraded phenanthrene under multiple conditions characterized by different concentrations of phenanthrene (100-400 mg l(-1) ), a broad range of salinities (0·1-15%) and varying pHs (6·0-10·0). Phenanthrene (200 mg l(-1) ) was completely depleted under 3% salinity and a pH of 9·0 within 6 days. The potential toxicity of phenanthrene and its generated metabolites towards the bacterium Vibrio fischeri was significantly reduced 10 days after the bioassay. On the basis of the identified metabolites, enzyme activities and the utilization of probable intermediates, phenanthrene degradation by strain AD-3 was proposed in two distinct routes. In route I, metabolism of phenanthrene was initiated by the dioxygenation at C-3,4 via 1-hydroxy-2-naphthoic acid, 1-naphthol, salicylic acid and gentisic acid. In route II, phenanthrene was metabolized to 9-phenanthrol and 9,10-phenanthrenequinone. Further study indicated that strain AD-3 exhibited a wide spectrum of substrate utilization including other polycyclic aromatic hydrocarbons (PAHs).
  
  
  CONCLUSIONS
  The results suggest that strain AD-3 possesses a high phenanthrene biodegradability and that the degradation occurs via two routes that remarkably reduce toxicity.
  
  
  CONCLUSIONS
  To the best of our knowledge, this work presents the first report of phenanthrene degradation by a halophilic PAH-degrading strain via two routes. In the future, the use of halophilic strain AD-3 provides a potential application for efficient PAH-contaminated hypersaline field remediation.
authors: State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, China.
authors: T-C
authors: TC
authors: Feng
authors: C-Z
authors: CZ
authors: Cui
authors: F
authors: F
authors: Dong
authors: Y-Y
authors: YY
authors: Feng
authors: Y-D
authors: YD
authors: Liu
authors: X-M
authors: XM
authors: Yang
mesh_terms: D020561:Alphaproteobacteria / Q000201:enzymology / Q000378:metabolism*; D001673:Biodegradation, Environmental; D002851:Chromatography, High Pressure Liquid; D008401:Gas Chromatography-Mass Spectrometry; D006863:Hydrogen-Ion Concentration; D053858:Metabolic Networks and Pathways; D010616:Phenanthrenes / Q000378:metabolism*; D054712:Salinity
chemical_list: D010616:Phenanthrenes