Celeribacter indicus sp. nov., a polycyclic aromatic hydrocarbon-degrading bacterium from deep-sea sediment and reclassification of Huaishuia halophila as Celeribacter halophilus comb. nov.

A taxonomic study was carried out on strain P73(T), which was isolated from deep-sea sediment of the Indian Ocean by enrichment of polycyclic aromatic hydrocarbons. The strain was able to degrade biphenyl, naphthalene, 2-methylnaphthalene, 2,6-dimethylnaphthalene, acenaphthene, anthracene, phenanthrene, dibenzothiophene, dibenzofuran, fluorene, 4-methyldibenzothiophene and fluoranthene, but not pyrene or chrysene. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain P73(T) formed a clade with the genera Celeribacter and Huaishuia within the family Rhodobacteraceae, with highest sequence similarity of 96.98 % to Celeribacter neptunius H 14(T), followed by Huaishuia halophila ZXM137(T) (96.42 %). The bacterium was Gram-stain-negative, oxidase- and catalase-positive, rod-shaped and non-motile. Growth was observed at salinities from 0.5 to 12 % and at temperatures from 10 to 41 °C. The principal fatty acids (>10 %) of strain P73(T) were summed feature 8 (C18 : 1ω7c/ω6c) and C19 : 0ω8c cyclo. The sole respiratory quinone was Q-10. The major lipids were phosphatidylglycerol, one unknown aminolipid, one unknown phospholipid and one unknown lipid; a second unknown phospholipid and one unknown glycolipid were present as minor components. The G+C content of the chromosomal DNA was 66.0 mol%. The combined genotypic and phenotypic data show that strain P73(T) represents a novel species of the genus Celeribacter, for which the name Celeribacter indicus sp. nov. is proposed. The type strain is P73(T) ( = MCCC 1A01112(T) = LMG 27600(T) = DSM 27257(T)). Phylogenetic study and existing phenotypic information also show that Huaishuia halophila should be transferred to the genus Celeribacter as Celeribacter halophilus comb. nov. (type strain ZXM137(T) = MCCC 1A06432(T) = CGMCC 1.8891(T) = LMG 24854(T)).