Alteromonas naphthalenivorans sp. nov., a polycyclic aromatic hydrocarbon-degrading bacterium isolated from tidal-flat sediment.

A Gram-staining-negative and halotolerant bacterium, designated SN2T, capable of biodegrading polycyclic aromatic hydrocarbons, was isolated from a tidal flat contaminated with crude oil in Korea. Cells were strictly aerobic, catalase- and oxidase-positive, motile rods, with a single polar flagellum. Growth was observed at 4-37 °C (optimum, 25-30 °C) at pH 6.0-9.0 (optimum, pH 7.0-7.5) and in the presence of 0.5-9.0% (w/v) NaCl (optimum, 2.0%). Only ubiquinone 8 was detected as the isoprenoid quinone, and summed feature 3 (comprising C16:1ω7c and/or iso-C15:0 2-OH), C16:0, C18:1ω7c and C12:0 were observed as the major cellular fatty acids. The major polar lipids consisted of phosphatidylethanolamine, phosphatidylglycerol, a glycolipid, an aminolipid and three unidentified lipids. The DNA G+C content was 43.5 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain SN2T formed a phylogenetic lineage with Alteromonas stellipolaris and Alteromonas addita within the genus Alteromonas, which was consistent with multilocus phylogenetic and MALDI-TOF MS analyses. Strain SN2T was most closely related to the type strains of A. stellipolaris, A. addita and Alteromonas macleodii, with 16S rRNA gene sequence similarities of 99.5, 99.3 and 98.4% and DNA-DNA relatedness of 48.7 ± 6.6, 24.9 ± 7.5 and 27.9 ± 8.4%, respectively. In conclusion, strain SN2T represents a novel species of the genus Alteromonas, for which the name Alteromonas naphthalenivorans sp. nov. is proposed. The type strain is SN2T ( = KCTC 11700BPT = JCM 17741T =KACC 18427T).