Pyruvate oxidation in Desulphovibrio desulphuricans.

The metabolism of Desulphovibrio desulphuricans does not appear to have been studied extensively. Stephenson and Stickland (1931) and Sisler and ZoBell (1950) showed that the organism can use gaseous hydrogen as a reducing agent for sulfate reduction. By growing cultures for several generations in mineral salt solution containing less than one part per million of sulfate, Sisler and ZoBell (1951a) were able to show that autotrophic sulfate-reducers can utilize C02 as the sole hydrogen acceptor. Neither growth nor hydrogen uptake, however, was nearly as rapid in the sulfate-free media as in similar media enriched with sulfate. However, washed cells of sulfate-reducers were found to reduce fumarate considerably more rapidly than sulfate (Sisler and ZoBell, 1951a). Sisler and ZoBell (1951b) reported the fixation of nitrogen by hydrogenase producing sulfate-reducers. Postgate (1952) reported that many strains of this organism were able to grow in the absence of sulfate if pyruvate was present. Pyruvate oxidation in bacterial extracts has been studied by several authors. In the presence of inorganic phosphate, cell-free extracts of Lactobacillus delbruecklii oxidatively decarboxyl-