Regulation of biosynthesis of pesticidal metabolic complexes inStreptomyces griseus

The complex of pesticidal metabolites produced byStreptomyces griseus LKS-1 consists of a peptide antibiotic (A), nonactic acids (B), macrotetrolides (C), pyrrolizines (D), and of cycloheximide. The latter unwanted phytotoxic compound was eliminated by treatment with mutagens. Combined approaches, including both genetic and physiological manipulations, resulted in the following alterations in the biosynthetic capacity: (1) A more than 80-fold increase in the production of C under a substantial decrease in the yields ofA, B andD, the ratio of the components ofC being steered toward the required more active ones; (2) a more than 300-fold increase in the production ofB under suppression of the formation ofA andC: (3) a 10-fold increase in the yields ofD under suppression ofA andC; (4 a significant increase in the yields ofA with eliminatingB, C andD. The level of inorganic phosphate in fermentation media and the sensitivity of the organism to carbon catabolite repression were important factors participating in the regulation of the above biosynthetic processes.