Aklanonic acid-producing mutants of Streptomyces galilaeus and Streptomyces peucetius var. caesius.

A number of blocked mutants was investigated which were obtained from taxonomically identified Streptomyces strains producing anthracyclines. Two of these mutants, NTG 061 derived from S. galilaeus F 198 and mutant 135 derived from S. peucetius var. caesius 601 F.I.1), accumulated an anthraquinone derivative which was identified as aklanonic acid. The results supplied further evidence that this compound was an intermediate of the biosynthetic pathway leading to different types of anthracyclines. It occurred before ring closure to the final tetracyclic anthracyclinone skeleton.