[Photoassimilation of organic compounds by Thiocapsa roseopersicina]

The cells of the purple sulphur bacterium Thiocapsa roseopersicina, strain BBS, incorporate 14C contained in succinate, lactate, pyruvate, and acetate. Organic compounds with an exception of pyruvate and fumarate produce no considerable effect on the rate of carbon dioxide photoassimilation by the cells though propionate, glycerol, glucose, lactate, and succinate decrease in the same conditions the rate of sulphide oxidation by 20-50%. The rate of 14C-bicarbonate incorporation into the cells in the absence of inorganic H-donor is highest in the presence of propionate, glycerol, glucose as well as lactate and pyruvate after growth of the bacterium on media containing these substrates. A possibility of utilization by T. roseopersicina, strain BBS, of exogenous organic substrates is discussed.