The Role of Propionic Acid in Penicillium baarnense. Formation of Homoorsellinic Acid by Utilization of Propionic Acid.

Abstract
From the medium of P. baarnense a new metabolite was isolated and shown to be 2-ethyl-4,6-dihydroxy-benzoic acid (homoorsellinic acid). This compound, the synthesis of which is described in this paper, could only be detected in cultures grown on Czapek [long dash]Dox medium when supplied with propionic acid. By the administration of CH3CH2C14 OONa, radioactive homoorsellinic acid was obtained. Results from the chemical degradation suggest a biosynthetic route of formation in which one propionyl-CoA unit is condensed with 3 malonyl-CoA units. The added propionate-1-C14 gave rise to radioactive orsellinic acid as well, the labeling pattern of which was shown to correspond to that obtained from acetate-1-C14.