Carbon dioxide--fixation in photosynthetic green sulfur bacteria.

The main products of carbon dioxide-fixation in washed suspensions of Chlorobium thiosulfatophilum are a polyglucose, alpha-ketoglutarate, and alpha-keto-beta-methylvalerate. All of these can be formed by a mechanism involving the reductive carboxylic acid cycle. The reductive pentose phosphate cycle appears to play a quantitatively minor role in carbon dioxide-fixation under these conditions.