Desulfarculus gen. nov.

Abstract

De.sulf.ar' cu.lus . L. pref. de from; L. n. sulfur sulfur; M.L. masc. n. arculus a small bow; M.L. masc. n. Desulfarculus a bow‐shaped sulfate‐reducer. Proteobacteria / Deltaproteobacteria / Desulfarcales / Desulfarculaceae / Desulfarculus Vibrio‐shaped cells, 0.5–0.7 × 1.5–4 μm . Occur singly or in pairs. Spore formation is not observed. Gram negative. The type species is motile. Strict anaerobe with respiratory type of metabolism. Chemoorganotroph, using formate, butyrate, and higher fatty acids as electron donors and carbon sources ; these compounds are completely oxidized to CO 2 . Growth on acetate and propionate is very slow. Sulfate and other oxidized sulfur compounds serve as terminal electron acceptors and are reduced to H 2 S. Sulfur, fumarate, and nitrate are not used as terminal electron acceptors. Growth does not usually occur in the absence of an external electron acceptor . Optimal temperature for growth, 35–39°C. Anoxic media (with sulfide as a reductant) are necessary for growth. Vitamins are not required. Cells contain cytochromes of the b ‐ and c ‐type. Carbon monoxide dehydrogenase activity is commonly observed, indicating the operation of the anaerobic C 1 ‐pathway (carbon monoxide dehydrogenase pathway, Woodpathway) for CO 2 fixation and complete oxidation of acetyl‐CoA. Desulfarculus species are widespread in freshwater habitats, but might occur in brackish or marine sediments as well. The mol % G + C of the DNA is : 66. Type species : Desulfarculus baarsii comb. nov . ( Desulfovibrio baarsii Widdel 1981, 382.)