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ThiobacillusRANK: GenusTAXONOMY: cellular organisms -> Bacteria -> Proteobacteria -> Betaproteobacteria -> Hydrogenophilales -> Hydrogenophilaceae -> Thiobacillus OVERVIEW: Small, Gram-negative, rod-shaped cells (0.3–0.5 × 0.9–4.0 µm). Some species are motile by means of polar flagella. No resting stages known. Energy is derived by the oxidation of one or more reduced sulfur compounds, including sulfides, sulfur, thiosulfate, polythionates, and thiocyanate. Sulfate is the end product of sulfur-compound oxidation, but sulfur, sulfite, and polythionates may be accumulated by most species, sometimes transiently. All species can fix carbon dioxide by means of the Benson–Calvin cycle and are capable of autotrophic growth; some species are obligately chemolithotrophic, while others are chemoorganotrophic. The genus currently includes obligate aerobes and facultative denitrifiers. Optimal pH of 2–8 with optimal temperature of 28–43°C. Distribution is seemingly ubiquitous in marine, freshwater, and soil environments, especially where oxidizable sulfur is abundant (e.g., sulfur springs, sulfide minerals, sulfur deposits, sewage treatment areas, and sources of sulfur gases, such as sediments or anaerobic soils releasing H2S).The mol% G + C of the DNA is: 62–67.Type species: Thiobacillus thioparus |