[Effect of orthophosphate on the formation of the antibiotic nonactin]

The potassium orthophosphate added to the media with developing actinomycetes inhibits the nonactin macrotetrolide antibiotic but causes the increase of mycelium growth. The degree of inhibition depends on the quantity of orthophosphate and almost doesn't depend on the time of its adding to the actinomycetes culture. The degree of phosphorus consumption by actinomycetes is higher, the more its content in the media. The antibiotic synthesis takes place during the phosphorus consumption but not after its exhaustion from the media.