Oceanibaculum indicum gen. nov., sp. nov., isolated from deep seawater of the Indian Ocean

Abstract

A taxonomic study was carried out on strain P24(T), which was isolated from a polycyclic aromatic hydrocarbon-degrading consortium, enriched from a deep-seawater sample collected from the Indian Ocean. The isolate was Gram-negative, rod-shaped, motile by means of a polar flagellum, moderately halophilic and capable of reducing nitrate to nitrite. Growth was observed at salinities of 0-9 % and at temperatures of 10-42 degrees C. The strain was unable to degrade Tween 80 or gelatin. The dominant fatty acids were C(16 : 0) (15.2 % of the total), C(18 : 0) (10.3 %), C(18 : 1)omega7c (52.0 %), C(18 : 1) 2-OH (4.7 %) and C(19 : 0)omega8c cyclo (4.7 %). The G+C content of the chromosomal DNA was 64.8 mol%. 16S rRNA gene sequence comparisons showed that strain P24(T) was related most closely to Thalassobaculum litoreum CL-GR58(T) (92.7 % similarity); levels of similarity between strain P24(T) and type strains of recognized species in the family Rhodospirillaceae were all less than 90.8 %. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain P24(T) formed a distinct evolutionary lineage within the family Rhodospirillaceae. Strain P24(T) could be distinguished from phylogenetically related genera based on differences in several phenotypic properties. On the basis of the phenotypic and phylogenetic data presented, strain P24(T) is considered to represent a novel species of a new genus, for which the name Oceanibaculum indicum gen. nov., sp. nov. is proposed. The type strain is P24(T) (=CCTCC AB 208226(T)=LMG 24626(T)=MCCC 1A02083(T)).