Regulation of nebramycin biosynthesis by inorganic phosphate.

The effect of inorganic phosphate on the biosynthesis of nebramycin factors 2, 4 and 5' was studied in Streptomyces tenebrarius strain A (forming 2, 4 and 5' in natural ratios) and its mutants B (forming predominantly 2), C (forming 2 as the only major product) and D (forming predominantly 5'). In phosphate-supplemented complex media, the production of 2 in A, B and C was reduced by 20-70%, while the yields of 5' remained unchanged in A and decreased by 30-60% in B. The production of 4 increased by 50-90% in A and was fully suppressed in B. In D the biosynthesis of the three factors was inhibited completely.