A genetic approach to the biosynthesis of the rifamycin-chromophore in Nocardia mediterranei. III. Isolation and identification of an early aromatic ansamycin-precursor containing the seven-carbon amino starter-unit and three initial acetate/propionate-units of the ansa chain.

A number of rifamycin non-producing UV-mutants derived from Nocardia mediterranei strains N813 (rifamycin B producer) and A10 (aro--mutant excreting shikimate derived from strain N813) were found to accumulate an identical complex of aromatic components instead of rifamycin B. The main component of this aromatic complex, product P8/1-OG, was isolated from six of these P--mutant strains and identified spectroscopically as a very early precursor in the biosynthesis of rifamycins.