D esulfocapsa

Abstract

De.sul.fo.cap'sa. L. pref. de , from; L. neut. n. sulfur , sulfur; L. fem. n. capsa , box; N.L. fem. n. Desulfocapsa , a sulfate‐reducing box. Desulfobacterota / Desulfobulbia / Desulfobulbales / Desulfocapsaceae / Desulfocapsa Cells are round‐ended or elongated rods with pointed ends, 0.8–0.9 µm × 2.0–3.5 µm. Cells are motile by means of single subpolarly inserted flagella. Gram‐stain‐negative. No spores are formed. Metabolism is strictly anaerobic chemoorganoheterotrophic and chemolithoautotrophic. Use of organic compounds limited to short organic alcohols, which are used as donor of electrons and are oxidized to their corresponding fatty acids. Sulfate is the electron acceptor and is reduced to sulfide. Inorganic sulfur compounds are disproportionated to sulfate and sulfide and support chemolithoautotrophic growth with CO 2 as carbon source. Fermentative growth with organic compounds is not possible. The optimal pH range for growth is 7.3–7.5. The optimal temperature range for growth is 20–30°C. NaCl is not required, and growth of the type strain is inhibited by NaCl concentrations higher than 15 g/l. The genus comprises only one species isolated from freshwater lake sediment. It contains cytochromes and not desulfoviridin. Occurs in sediments of freshwater lake close to the anoxic/oxic interface. DNA G + C content (mol%) : 50.7 (LC), 53.6 (genome). Type species : Desulfocapsa thiozymogenes Janssen, Schuhmann, Bak and Liesack 1997, 601 VP (Effective publication: Janssen, Schuhmann, Bak and Liesack 1996, 190).