Incertae Sedis VIII. Thiomonas

Thi.o.mo' nas. Gr. n. thios sulfur; Gr. fem. n. monas a unit, monad; M.L. fem. n. Thiomonas sulfur monad. Proteobacteria / Betaproteobacteria / Burkholderiales / Comamonadaceae / incertae Sedis VIII. Thiomonas The phenotypic description is that of the general traits for group II of Thiobacillus (Kelly and Harrison, 1989; Moreira and Amils, 1997). Gram-negative, nonsporeforming, short rods that are about 0.3–0.5 × 1–3 µm. Cells motile by means of single polar flagella. Obligate aerobes. Optimal temperature 30–36°C for mesophilic species and 50°C for moderately thermophilic species. Optimal pH between 3 and 6. Facultative chemolithoautotrophs; optimal growth occurs in mixotrophic media supplemented with reduced sulfur compounds and organic supplements (yeast extract, peptone, some sugars, and amino acids). Chemoorganotrophic growth on yeast extract, Casamino acids, peptone, and meat extract. Chemolithoautotrophic on thiosulfate, tetrathionate, S0, and H2S. Do not oxidize ferrous iron. Sensitive to ampicillin. Contain ubiquinone Q-8. Members of the Betaproteobacteria. The mol% G + C of the DNA is: 61–69. Type species: Thiomonas intermedia (London 1963) Moreira and Amils 1997, 527 (Thiobacillus intermedius London 1963, 335.) Keywords: Thiomonas; Thiomonas intermedia; Comamonadaceae