On the origin of unsaturated fatty acids in clostridia.

The formation of long chain unsaturated fatty acids from the corresponding saturated acids in animals was established by the work of Schoenheimer and Rittenberg (1) and Stetten and Schoenheimer (2). Recent studies in this laboratory have shown that in yeast the formation of Ag-unsaturated fatty acids is catalyzed by an enzyme system acting on the coenzyme A derivatives of the corresponding saturated fatty acids and requiring molecular oxygen and reduced triphosphopyridine nucleotide (3). In view of the aerobic nature of this process, it became of interest to test the ability of anaerobic microorganisms to synthesize unsaturated fatty acids. The present communication presents evidence for the synthesis of olefinic fatty acids in Clostridia by an anaerobic mechanism together with observations on the interrelationships between saturated and unsaturated fatty acids in these organisms.