THE METABOLISM OF SPECIES OF STREPTOMYCES V

Abstract

S. coelicolor in aerated culture accumulates succinic acid from utilizable sugars and polyhydric alcohols. Over a wide range of glucose concn., the accumulation of succinate is proportional to the glucose consumed, indicating that its formation is not the result of luxury supply of carbohydrate. Resting cells form large amts. of succinate from fumarate, malate, and pyruvate, less from citrate and alpha-ketoglutarate, and none from acetate. Acetate-2-C14 as the sole source of C is metabolized without dilution; in the presence of glucose specific activity is diluted significantly and labeled succinate can be isolated. Carbon-14 from C14O2 is also incorporated in succinate. Succinic acid formation by resting or growing cells is limited by available CO2; in the absence of CO2 pyruvic acid accumulates. It is concluded that bulk formation of succinate occurs via carbox-ylation of pyruvic acid or a derivative of it and reduction of the product; any contribution from the operation of a tricarboxylic acid cycle or from condensation of C2 compounds is negligible in comparison.