ENDOGENOUS FERMENTATION IN THIORHODACEAE

Abstract

The endogenous fermentation of a Chromatium sp. strain D, grown in an inorganic medium containing thiosulfate, results in the formation of H2S, CO2 and acetic acid. The evidence indicates that the source of the H2S is stored elemental S which is enzymatically reduced in a reaction coupled with the oxidation of reserve organic materials. Reduction of added Na2S35O4 is negligible under these conditions. From cells grown on an inorganic medium containing H2 as H-donor, CO2, acetic acid and H2 are produced, but not H2S unless colloidal S is added. The endogenous fermentations of both Chromatium and baker''s yeast are stimulated by the addition of colloidal S. A continuous culture method is described for the cultivation of the Thiorhodaceae.