Conversion of Soybean Phytosterol into Androsta-4,9(11)-diene-3,17-dione

In this study, we developed a method for the production of androsta-9(11)-diene-3,17-dione (Δ9(11)-AD), which is a combination of phytosterol side-chain microbial oxidation with simultaneous 9α‑hydroxylation and subsequent chemical regio-selective dehydration of 9α-hydroxy-3,17-diketo-intermediate without isolation and purification. Phytosterol was converted into 9α-hydroxyandrost-4-ene-3,17-dione (9-OH-AD) with the use of the wild-type Mycobacterium sp. VKM Ac-1817D strain. The product was extracted from the culture medium with the use of an organic solvent and dehydrated in the extract with mineral acid. The resulting Δ9(11)-AD was purified with the selective crystallization method. Minor products were isolated and identified. It has been shown that this strain is capable of sterol transformation with the formation of methyl ester of 9α-hydroxypregn-4-ene-3-one-20-carboxylic acid. Our approach makes it possible to simplify the flow chart for production of the target compound. It not only eliminates 9-OH-AD loss but also minimizes the amount of production waste.