The effect of inorganic phosphate on the production of avermectin in Streptomyces avermitilis.

The effect of phosphate on the production of avermectin B1a, growth and utilization of glucose in the course of cultivation of Streptomyces avermitilis on a complex and chemically defined medium has been studied. Phosphate added at the beginning of cultivation at 1-20 mmol/l did not distinctly affect the production of secondary metabolite. From the results it follows that the biosynthesis of avermectin tolerates high concentrations of phosphate in the medium.