Determination of pools of tricarboxylic acid cycle and related acids in bacteria

Abstract

Methods for sampling, extracting, and quantitating the metabolic pools of organic acids from bacteria have been developed. The concentration of these metabolites was determined by a new gas chromatographic method that can quantitatively determine the levels of lactate, pyruvate, fumarate, succinate, malate, α-ketoglutarate, and citrate. Values obtained were confirmed by fluorimetric analyses of five of the individual acids. In Escherichia coli, pools range from about 1 to 5 μmol/g of dry weight, with a variation in replicate samples of 5 to 15%. Under similar conditions, these pools in Bacillus licheniformis are in the same range, although the pyruvic acid pool is significantly larger.