Abstract
A microaerophilic, Gram-negative, motile, and spiral-shaped bacterium, designated Y-M2(T), was isolated from oil sludge of Shengli oil field. The optimal growth condition of strain Y-M2(T) was at 25 °C, pH 7.0, and in the absence of NaCl. The major polar lipid was phosphatidylethanolamine. The main cellular fatty acid was iso-C(17 : 0) 3-OH. It contained Q-9 and Q-10 as the predominant quinones. The DNA G+C content was 68.1 mol%. Strain Y-M2(T) showed the highest 16S rRNA gene sequence similarity to Telmatospirillum siberiense 26-4b(T) (91.1 %). Phylogenetic analyses based on 16S rRNA gene and genomes showed that strain Y-M2(T) formed a distinct cluster in the order Rhodospirillales. Genomic analysis showed that Y-M2(T) possesses a complete nitrogen-fixation cluster which is phylogenetically close to that of methanogene. The nif cluster, encompassing the nitrogenase genes, was found in every N(2)-fixing strain within the order Rhodospirillales. Phylogeny, phenotype, chemotaxonomy, and genomic results demonstrated that strain Y-M2(T) represents a novel species of a novel genus in a novel family Oleispirillaceae fam. nov. in the order Rhodospirillales, for which the name Oleispirillum naphthae gen. nov., sp. nov. was proposed. The type strain is Y-M2(T) (=CCAM 827(T)=JCM 34765(T)).