The diolode macrolide vermiculin (1) together with the three unsaturat
ed aliphatic ketoacids vermiculinic (2), vermiculic (3) and 4-deoxover
miculic acid (4) were isolated from the cultivation broth of Penicilli
um vermiculatum. Biotransformation of 2 and 3 with growing and resting
cells of P. vermiculatum was studied. We suppose, that 2 which is for
med from 3, is the ultimate progenitor of 1.