Hydrogenophaga soli sp. nov., isolated from rice field soil

A novel Gram-stain-negative bacterial strain, designated strain S10^T, was isolated from soil collected in a rice field in Goyang, South Korea. Cells of strain S10^T were strictly aerobic, motile and rod-shaped. Colonies were round, convex, smooth and white. The strain grew optimally at 37 °C, pH 7.0 and 0 % (w/v) NaCl. Phylogenetic analysis of the 16S rRNA gene sequence of strain S10^T revealed that the bacterium belongs to the family Comamonadaceae and is related to members of the genus Hydrogenophaga, with Hydrogenophaga caeni EMB71^T being its closest relative (97.9 % sequence similarity). The DNA G+C content of strain S10T was 68.2 mol%. Strain S10^T contained phosphatidylethanolamine and diphosphatidylglycerol as the major polar lipids. The major fatty acids were C_{16: 0} and summed feature 3 (C_{16: 1} ω7c and/or iso-C_{15: 0} 2-OH). The predominant respiratory quinone was ubiquinone Q-8. DNA–DNA hybridization values of strain S10^T with Hydrogenophaga caeni KCTC 12613^T, Hydrogenophaga atypica DSM 15342^T and Hydrogenophaga defluvii DSM 15341^T were 16.1±4.8, 49.0±3.2 and 21.9±8.8 %, respectively. Based on phylogenetic distinctiveness, DNA–DNA hybridization and specific physiological and biochemical characteristics, strain S10^T (=KCTC 52520^T=JCM 31711^T) is classified as a novel species of the genus Hydrogenophaga, for which the name Hydrogenophaga soli sp. nov. is proposed.