Desulfotomaculum

Abstract

De.sul.fo.to.ma'cu.lum. L. pref. de from; L. n. sulfo sulfur; L. n. tomaculum a kind of sausage; N.L. neut. n. Desulfotomaculum a sausage‐shaped sulfate reducer. Firmicutes / “Clostridia” / Clostridiales / Peptococcaceae / Desulfotomaculum Straight or curved rod‐shaped cells, 0.3–2.5 × 2.5–15 µm with rounded or pointed ends. Occur singly or in pairs. Spores oval or round, terminal to central, causing swelling of the cells. Stain Gram‐positive, although often only detected by electron microscopy. Cells are motile by single polar or peritrichous flagella, but motility can be lost during cultivation. Strict anaerobe with a respiratory type of metabolism. Chemo‐organotrophs or chemoautotrophs . Simple organic compounds are used as electron donor and carbon sources, and are either completely oxidized to CO 2 or incompletely to acetate. Some species can grow on H 2 autotrophically with CO 2 as the sole carbon source; one species can grow on CO alone. Sulfate, and usually sulfite and thiosulfate, serve as terminal electron acceptors and are reduced to H 2 S. Sulfur and nitrate are not used as electron acceptors. Fermentative growth has been observed for some species. Desulfoviridin is absent. The major menaquinone is MK‐7 . Growth occurs in simple defined media containing sulfide as a reductant. Some species require vitamins or yeast extract. Some species can fix N 2 . The optimum temperature range for growth is 30–37°C for mesophilic and 50–65°C for thermophilic species. The optimum pH range for growth is 6.5–7.5. Carbon monoxide dehydrogenase activity has been demonstrated for some species. Desulfotomaculum species are common in anoxic freshwater, brackish or marine sediments. DNA G + C content ( mol %): 37.1–56.3. Type species : Desulfotomaculum nigrificans (Werkman and Weaver 1927) Campbell and Postgate 1965, 361 AL ( Clostridium nigrificans Werkman and Weaver 1927, 63).