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Effect of Nitrogen Source in Cultivation Medium on the 9α-Hydroxylation of Pregnane Steroids by Resting Rhodococcus Sp. Cells

ABSTRACT The influence of the source of nitrogen in the cultivation media on 9α-hydroxylating activity of resting Rhodococcus sp. cells was investigated. Two pregnane steroids 3β-hydroxy-16α,17α-epoxy-5α-pregnane-20-one (5α-H) and 3β-hydroxy-16α,17α-epoxy-5- pregnen-20-one (Δ5) were used as substrates. Results obtained showed that the source of nitrogen in the cultivation medium significantly affected both the level of product accumulation and the dynamics of their formation. It is worth mentioning the difference in the hydroxylating activity of cell depot prepared on commercial dehydrated or freshly prepared nitrogen sources. Thus, the cultivation medium with Triptose (Difco) gave a Rhodococcus sp. cell depot actively accumulating hydroxylated derivatives from 5α-H while the most suitable for accumulation of such derivatives from Δ5 was media containing freshly prepared meat extract.