Tepidiphilus baoligensis sp. nov., a Novel Bacterium of the Family Hydrogenophilaceae Isolated from an Oil Reservoir.

A Gram-negative, aerobic, motile, non-spore-forming and rod-shaped bacterium, designated strain B18-69, was isolated from oil-well production liquid in Baolige oilfield, China. The strain was able to grow at pH 6-9.5 (optimum at pH 7), in 0-4% (w/v) NaCl (optimum at 0.5-1%, w/v) and at 35-60 °C (optimum at 55 °C). Major cellular fatty acids were C, C cyclo ω8c, C cyclo and C ω7c. The predominant respiratory quinone was ubiquinone 8. Major polar lipids were phosphatidylethanolamine (PE), phosphatidylglycerol (PG), diphosphatidylglycerol (DPG) and phosphatidylcholine (PC). Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain B18-69 was most closely related to Tepidiphilus margaritifer DSM 15129 (98.8% similarity). The draft genome of strain B18-69 was composed of 2,250,419 bp, and the G+C content was 64.6 mol%. Average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strain B18-69 and T. margaritifer DSM 15129 were 90.9% and 68.9%, respectively. Genotypic and phenotypic features indicate that strain B18-69 represents a novel species of the genus Tepidiphilus, for which the name Tepidiphilus baoligensis sp. nov. is proposed. The type strain is B18-69 (= CGMCC 1.13573 = KCTC 62782).