Sulfurovum denitrificans sp nov., an obligately chemolithoautotrophic sulfur-oxidizing epsilonproteobacterium isolated from a hydrothermal field

A novel marine sulfur-oxidizing bacterium, designated strain eps51(T), was isolated from a surface rock sample collected from the hydrothermal field of Suiyo Seamount on the Izu-Bonin Arc in the Western Pacific Ocean. This bacterium was Gram-staining-negative, non-motile and rod-shaped. Strain eps51(T) grew chemolithoautotrophically, by sulfur-oxidizing respiration with elemental sulfur and thiosulfate as electron donors and used only carbon dioxide as a carbon source. Oxygen and nitrate were used as its electron acceptors. The isolate grew optimally at 30 degrees C, at pH 7.0 and with 3 % NaCl. The predominant fatty acids were C-16: (1)omega 7c, C-18 (:) (1)omega 7c and C-16 (:) (0). The respiratory quinone was menaquinone-6 and the genomic DNA G+C content was 40.0 mol%. Phylogenetic analysis based on 16S rRNA gene sequence revealed that eps51(T) represented a member of the genus Sulfurovum and the closest relative was Sulfurovum aggregans (96.7 %). Based on its phylogenetic position along with its physiological and chemotaxonomic characteristics, the name Sulfurovum denitrificans sp. nov. is proposed, with the type strain eps51(T) (=NBRC 102602(T)=DSM 19611(T)).