Phenanthrene Metabolites from a New Polycyclic Aromatic Hydrocarbon-Degrading Bacterium <i>Aeromonas salmonicida</i> subsp. <i>Achromogenes</i> Strain NY4

<p>A new polycyclic aromatic hydrocarbon (PAH)-degrading Gram-negative bacterium <i>Aeromonas salmonicida</i> subsp. <i>achromogenes</i> strain NY4 was isolated from coking wastewater sludge. Strain NY4 could not grow on1-hydroxy-2-naphthoic acid, hexadecane or hexanol as sole carbon source but phenanthrene. This strain was able to utilize several known microbial metabolites of PAHs, including catechol, protocatechuic acid, salicylic acid, and phenol as sole carbon source. The mixture of the acidic and neutral fraction, acidic fraction alone and neutral fraction alone of phenanthrene metabolites were prepared and analyzed by GC-MS. A total of at least 27 metabolites were identified as the degradation products of phenanthrene by strain NY4. Among them, 1-hydroxy-α-oxo-2-naphthaleneacetic acid, 2-hydroxy-α-oxo-1-naphthaleneacetic acid, 2-hydroxy-1-(1-hydroxy-2-naphthalenyl)-ethanone, 1,2-dihydro naphtha [2,1-b] furan-2-ol and 2,3-dihydro naphtha [1,2-b] furan-2-ol have not been reported as the metabolites of phenanthrenes so far. The accumulation patterns of phenanthrene metabolite accumulation by strain NY4 depended on the incubation time, inoculum size and concentration of phenanthrene. Based on the degradation metabolites of phenanthrene by strain NY4, degradation pathways are proposed. This is the first report of PAH degradation in <i>Aeromonas salmonicida</i>, which lay the foundation for recognition and further characterization of PAH degradation metabolites and pathways in <i>Aeromonas salmonicida</i> strains.