REGULATION OF BIOSYNTHESIS OF PESTICIDAL METABOLIC COMPLEXES IN STREPTOMYCES-GRISEUS

The complex of pesticidal metabolites produced by Streptomyces griseus LKS-1 consists of a peptide antibiotic (A), nonactic acids (B), macro tetrolides (C), pyrrolizines (D), and of cycloheximide. The latter unw anted phytotoxic compound was eliminated by treatment with mutagens. C ombined approaches, including both genetic and physiological manipulat ions, resulted in the following alterations in the biosynthetic capaci ty: (1) A more than 80-fold increase in the production of C under a su bstantial decrease in the yields of A, B and D, the ratio of the compo nents of C being steered toward the required more active ones; (2) a m ore than 300-fold increase in the production of B under suppression of the formation of A and C; (3) a 10-fold increase in the yields of D u nder suppression of A and C; (4) a significant increase in the yields of A with eliminating B, C and D. The level of inorganic phosphate in fermentation media and the sensitivity of the organism to carbon catab olite repression were important factors participating in the regulatio n of the above biosynthetic processes.