Metabolism of Barbital by Streptomyces mediterranei

The metabolism of barbital in cultures ofStreptomyces mediterranei was studied. Small quantities were transformed during the fermentation. Four compounds were isolated and identified as 5-ethyldialuric acid, 5-ethylbarbituric acid, 5-(β-hydroxyethyl)-5-ethylbarbituric acid, and diethylmalonic acid monoureid. The influence of these compounds on the production of rifamycin was of minor importance. With the aid of C14 -barbital, it was established that neither barbital nor any of its metabolic products can be considered as precursors of the rifamycin B.