[The role of succinic acid in the biosynthesis of levorin].

The influence of succinic acid as a component of media for biosynthesis of levorin, a polyenic antibiotic was studied. It was shown that with the use of the soybean-corn medium supplemented with succinic acid (0.05-0.

[Role of p-aminobenzoic acid in levorin biosynthesis].

The effect of p-aminobenzoic acid on the biosynthesis of levorin was studied. It was shown that in the presence of exogenic p-aminobenzoic acid the antibiotic activity increased by 11 per cent. The acid added was transformed into p-aminoacetophenone which was partially used for levorin synthesis and partially accumulated in the mycelium in a free state.

[Determination of p-aminoacetophenone and changes in its levels in a levorin producer depending on culture conditions].

A method for spectrophotometric determination of p-aminoacetophenone (p-AAP) in the mycelium and fermentation broth filtrates of organisms producing polyenic macrolide antibiotics is described. The level of p-AAP accumulation was studied as applicable to the biosynthesis of levorin, a polyenic antibiotic of the heptaen series. The levels of p-AAP under usual conditions of the levorin-producing organism cultivation and under conditions of its stimulation with the products of the vital activity of yeast-like fungi were compared.