Hydrogenophaga

Hy.dro.ge.no' pha.ga . Gr. n. hydro water; Gr. n. gennao to create; M.L. hydrogenum hydrogen, that which produces water; Gr. v. phagein to eat; M.L. fem. n. Hydrogenophaga eater of hydrogen. Proteobacteria / Betaproteobacteria / Burkholderiales / Comamonadaceae / Hydrogenophaga Straight to slightly curved rods , 0.3–0.6 × 0.6–5.5 µm, occurring singly or in pairs. Gram negative . Motile by means of one or , rarely , two polar to subpolar flagella . Colonies are yellow due to the presence of carotenoid pigments . Aerobic . Oxidase positive and catalase positive , except for H . pseudoflava , which is catalase variable. Chemoorganotrophic or chemolithoautotrophic , using the oxidation of H 2 as an energy source and CO 2 as a carbon source. Oxidative carbohydrate metabolism occurs, with oxygen as the terminal electron acceptor; alternatively, two species ( H . pseudoflava and H . taeniospiralis ) are capable of heterotrophic denitrification of nitrate. Good growth occurs on media containing organic acids, amino acids, or peptone; there is less versatility in the use of carbohydrates. Cellular lipids contain 3‐hydroxyoctanoic acid (C 8:0 3OH ) either alone or together with 3‐hydroxydecanoic acid (C 10:0 3OH ); 2‐hydroxy‐substituted fatty acids are absent. Ubiquinone Q‐8 is the main quinone. Putrescine and 2‐hydroxyputrescine are present in approximately equimolar concentrations, either exclusively or as the dominant polyamines. The mol % G + C of the DNA is : 65–69. Type species : Hydrogenophaga flava (Niklewski 1910) Willems, Busse, Goor, Pot, Falsen, Jantzen, Hoste, Gillis, Kersters, Auling, and De Ley 1989, 329 ( Pseudomonas flava (Niklewski 1910) Davis, Doudoroff, Stanier, and Mandel 1969, 385; Hydrogenomonas flava Niklewski 1910, 123.)