Biosynthesis of polyene antibiotics and sterols under the action of exogenous β-sitosterol by Streptomyces netropsis IMV Ac-5025

Abstract Unexplained aspects of the biosynthetic capacity of Streptomyces netropsis IMV Ac-5025 were studied. Correlations in the biosynthesis of polyene antibiotics with other biological active substance by the producer were found for the first time. Exogenous β-sitosterol caused an increase of polyene antibiotics biosynthesis and their excretion from the cells into culture liquid. Their sum was raised 4.5-fold in biomass and 2.5-fold in culture liquid under the action of 10 μg/mL of β-sitosterol. Biomass accumulation was almost doubled under the action of 5 μg/mL of exogenous substance in the synthetic nutrient medium and 1.5-fold – in organic. Squalene, ergosterol, cholesterol, stigmasterol, β-sitosterol, and 24-epibrasinolide were accumulated in producer cells. Their sum was ranged from 1.753 to 4.750 mg/g ADB and was increased 2.7-fold under the action of 0.25 μg/mL of β-sitosterol. These results are important for understanding the complex relationships of metabolic pathways in streptomycetes cells.