Fatty acid synthesis by enzyme preparations of Clostridium kluyveri; the aerobic oxidation of ethanol and butyrate with the formation of acetyl phosphate.

The anaerobic bacterium Clostdium kluyveti can catalyze the conversion of ethanol and acetate to butyrate and caproate (6). Tracer studies with growing cultures of this organism (2) have shown that this conversion involves an oxidation of ethanol to a a-carbon compound (“active” acetate) that is in approximate equilibrium with acetate. This activated a-carbon substance then condenses with ordinary acetate to form a Cd compound that is reduced to butyrate (see Scheme I, Paper I of this series). If the current idea is correct that biological oxidation-reduction reactions involve the removal or addition of only 2 electrons at a time, it follows that the conversion of alcohol and acetate to butyrate must involve a number of intermediates. For example, the oxidation of ethanol to the “active” acetate would be a two-step process involving at least one intermediate compound. Similarly, the reduction of the postulated Cd compound to butyrate should involve at least one intermediate compound in a state of oxidation corresponding to P-hydroxybutyrate. Thus it is necessary to postulate a series of reactions in which at least four intermediate compounds are formed in the conversion of alcohol to butyrate.