Desulfovibrio

Abstract

De.sul.fo.vi' bri.o . L. pref. de from; L. n. sulfur sulfur; L. v. vibrio to vibrate; M.L. masc. n. Vibrio that which vibrates, a generic name; M.L. n. Desulfovibrio a vibrio that reduces sulfur compounds. Desulfobacterota / Desulfovibrionia / Desulfovibrionales / Desulfovibrionaceae / Desulfovibrio Curved or occasionally straight rods , sometimes sigmoid or spirilloid, 0.5–1.5 × 2.5–10.0 μm . The morphology is influenced by age and environment; descriptions refer to freshly grown cultures in anoxic sulfate media. Spore formation is absent . Gram negative. Motile by means of a single or lophotrichous polar flagella. Obligately anaerobic growth in pure cultures. Possess mainly a respiratory type of metabolism with sulfate or other sulfur compounds as the terminal electron acceptors, being reduced to H 2 S ; however, the metabolism is sometimes fermentative. Media containing a reducing agent are required for growth. In a few cases, a vitamin requirement has been reported. Some species and subspecies are moderately halophilic. Optimal growth temperature, usually 25–35°C; upper limit normally 44°C. No thermophilic species have been reported. Thermophilic Desulfovibrio species formerly described have been reclassified and currently belong to the genera Thermodesulfovibrio and Thermodesulfobacterium . Chemoorganotrophic. Most species oxidize organic compounds such as lactate incompletely to acetate, which cannot be oxidized further . Carbohydrates are utilized by few species. One species, D. inopinatus , can use hydroquinone as electron donor and carbon source for growth. Cells contain c ‐type cytochromes (such as c 3 ) and usually b ‐type cytochromes. All members of the genus Desulfovibrio contain desulfoviridin. Hydrogenase is usually present. Strains of some species may show chemolithoheterotrophic growth, using H 2 as electron donor and assimilating acetate and CO 2 , or yeast extract, as carbon sources. Gelatin is not liquefied. Nitrate is sometimes reduced to ammonia. Some species can reduce oxygen or metal ions, but growth has never been observed with these electron acceptors in pure cultures. Molecular nitrogen is sometimes fixed. Species generally show some degree of antigenic cross reaction. Habitats: anoxic mud of fresh and brackish water and marine environments; intestines of animals; manure and feces. The mol % G + C of the DNA is : 46.1–61.2. Type species : Desulfovibrio desulfuricans (Beijerinck 1895) Kluyver and van Niel 1936, 397 ( Spirillum desulfuricans Beijerinck 1895, 113.)