Salipiger pentaromativorans sp. nov., a polycyclic aromatic hydrocarbon-degrading bacterium isolated from mangrove...

Polycyclic aromatic hydrocarbons (PAHs) have been recognized as a potential health risk and are widespread in nature due to their intrinsic chemical stability and high recalcitrance to degradation. A taxonomic study was carried out on strain P9^T, which was isolated from a PAH-degrading consortium, enriched from the mangrove sediment from Zhangzhou, PR China. The isolate was chemoheterotrophic, aerobic, Gram-stain-negative, short-rod shaped, and motile by one polar flagellum. Growth was observed at salinities from 0.5-6.0 % (optimum, 3 %), at pH 4-9 (optimum, pH 7) and at 10-41 °C (optimum, 25-30 °C). It did not synthesize bacteriochlorophyll a. Catalase and oxidase activities were positive. Acid was produced from starch, amygdalin, arbutin, cellobiose, d-fructose, maltose, d-mannitol, melezitose, melibiose, raffinose, d-ribose, sucrose, trehalose, d-xylose, aesculin ferric citrate, gentiobiose, glycogen, l-arabinose, l-rhamnose, methyl α-d-glucopyranoside, methyl β-d-xylopyranoside, N-acetylglucosamine and salicin, and weakly positive for d-arabitol, d-galactose, lactose, turanose and glycerol. Phylogenetic analysis revealed that strain P9^T fell within the clade comprising the type strains of Salipiger species and formed an independent cluster with Salipiger profundus, which was distinct from other members of the family Rhodobacteraceae. The 16S rRNA gene sequence comparisons showed that strain P9^T was most closely related to Salipiger bermudensis HTCC 260^T (96.7 %), and other species of the genus Salipiger (95.7-94.2 %). Strain P9^T had the highest digital DNA-DNA hybridization value with S. profundus CGMCC 1.12377^T (25.0 %) and the highest average nucleotide identity (ANIb and ANIm) values with S. profundus CGMCC 1.12377^T(80.3 and 85.8 %, respectively). The sole respiratory quinone was quinone 10. The dominant fatty acids were C_18 : 1  ω7c (61.4 %), C_16 : 0 (17.5 %) and C_19 : 0  ω8c cyclo (7.6 %). The G+C content of the chromosomal DNA was 65.8 mol%. In the polar lipid profile, phospholipid, phosphatidylglycerol, aminolipid, glycolipid and phosphatidylethanolamine were the major compounds. Based on the phenotypic and phylogenetic data, strain P9^T represents a novel species of the genus Salipiger, for which the name Salipiger pentaromativorans sp. nov. is proposed. The type strain is P9^T (=CCTCC AB 209290^T=LMG 25701^T=MCCC 1F01055^T).