UTILIZATION OF REDUCING POWER IN LIGHT-LIMITED CULTURES OF CHROMATIUM-VINOSUM DSM-185

This study describes how the phototrophic organism Chromatium vinosum, when grown under different degrees of light limitation, distributes t he reducing power initially present in the medium as hydrogen sulfide. Under all the conditions of illumination tested, sulfur was the major store of reducing power. Glycogen, which was virtually absent under l ight limitation, accounted for 31.6% of the stored reducing power at s aturating irradiances. Analysis of the electron budget showed that und er light-limiting conditions, an important fraction of reducing power did not appear in storage products or in structural cell material. Ana lysis of dissolved organic carbon in the supernatant of the culture in dicated the excretion of organic compounds.