ACETIC ACID OXIDATION BY ESCHERICHIA COLI AND AEROBACTER AEROGENES

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Abstract
E. coli oxidizes acetate, the Szent-Gyorgyi C4 dicarboxylic acids, pyruvate and alpha-ketoglutarate when grown on either glucose or glycerol containing medium. When acetic acid constitutes the chief C source of the growth medium, the C2 acid is attacked (manometrically) at a much faster rate per unit time than cells grown in either glucose or glycerol. Simultaneously, an increased rate of oxidation is observed with succinate, fumarate, malate, oxalacetate and pyruvate. Oxidation of alpha-ketoglutarate and cis-aconitate remains low. These results suggest that the C4 dicarboxylic acids, as well as pyruvate, participate in the oxidation of acetic acid, at least in the case of E. coli. By the use of cyclohexanol and arsenious oxide, it was possible to demonstrate that an initial condensation of pyruvate with some C4 acid is not involved in the oxidation of pyruvic acid in the organisms studied. Aerobically, the keto acid is initially oxidatively decarboxylated to acetate and CO2, the former being further oxidized to CO2 and water by a pattern outlined above.