Isolation and characterization of Pseudoalteromonas strains with divergent polycyclic aromatic hydrocarbon catabolic properties

Fifteen strains of polycyclic aromatic hydrocarbon (PAH)-catabolizing bacteria, identified as Pseudoalteromonas spp. were isolated from Eagle Harbor, Puget Sound, USA, using a most probable number procedure in which naphthalene or phenanthrene was the sole carbon and energy source. Despite having identical 16S rDNA sequences, some catabolized many PAHs, whereas others oxidized only naphthalenes. A putative naphthalene 1,2-dioxygenase gene fragment was polymerase chain reaction-amplified from the naphthalene-degrading strains and shown to be almost identical to a gene present in Neptunomonas naphthovorans, suggesting horizontal transfer.