TAXONOMY: cellular organisms -> Bacteria -> Proteobacteria -> Betaproteobacteria -> Burkholderiales -> Burkholderiaceae -> Ralstonia
Gram-negative asporogenous rods. Motile or nonmotile; motile species have either a single polar flagellum or peritrichous flagella. Aerobic, having a strictly respiratory type of metabolism with oxygen as the terminal electron acceptor. Able to grow on ordinary peptone media. One species, R. eutropha, is a facultatively chemolithoautotrophic organism (a knallgas bacterium) and can oxidize H2 as an electron donor. Furthermore, under anaerobic conditions, R. eutropha is able to utilize nitrate as the terminal electron acceptor. Colony color is beige in most species. Strains of R. eutropha are regarded as having outstanding biotechnological potential. Oxidase and catalase positive. Lysine and ornithine decarboxylase negative. Ubiquinone Q-8 is the major respiratory quinone. None of the 26 carbohydrates tested are oxidized by the type strains of R. campinensis and R. taiwanensis. Among 95 other organic compounds, 10—mainly salts of organic acids—were assimilated and 39 other compounds were not assimilated by all of the 11 type strains. Cellular lipids of this genus contain two kinds of phosphatidylethanolamine, PE-1 and PE-2. The latter possesses 2-hydroxy fatty acid at sn-2 position of the glycerol moiety. Major components of cellular fatty acids are C16:0, a mixture of C18:1 ω9t and C18:1 ω7c, and C14:0 3OH. At present the genus is composed of 11 validated species. The sequence similarity of 11 type strains to that of Ralstonia pickettii—the type species—ranges from 95.0% to 98.1%. The genus contains plant pathogens, human pathogens, knallgas bacteria, and metal-resistant bacteria.
The mol% G + C of the DNA is: 64.0–68.0.
This genus contains microbial species that can reside in the human gastrointestinal tract. [PMC 4262072]