Studies On The Reaction Of Steroid C₁₁α-hydroxylation By Rhizopus Nigricans

Steroid hormone drug is the second medicine whose production is just inferior to antibiotic. In the production of steroid hormone drug, some groups of steroid need modifying, C₁₁α-hydroxylation is one of the most important ones .In this papper, the best medium was determined, the effect of carbon source and pH condition in the oxidation phase was studied, and to deal with the problem of DO in the course of C₁₁α-hydroxylation, the method of adding water was studied.The optimal medium of C₁₁α-hydroxylation was glucose 30g/L, corn steep liquor 25g/L,(NH₄)₂SO₄1.6g/L,silkworm pupae powder3g/L. Cultivating 22h was the best time to add substrate. The former treatment of substrate was still adopted that was, steroid:ethanol:water=2:1.8:4.3.When adding 4g/L DMSO to the medium the conversion rate reached to 35.8%. When adding 5g/L Tween80 to the medium the conversion rate reached to 35.1%, and the conversion rate reached to 35.3% when adding 3g/L Tween80 at the point of adding substrate. When using complex carbon source C(glucose:dextrin=1:1) the conversion rate was increased by 2% at the level of 100L bioreactor. Adjusting pH to 6.0 at the point of adding substrate, the pH remained 4.0-5.0 in hydroxylation phase, the conversion rate was increased by 2% at the level of 100L bioreactor.To deal with the problem of DO in the course of C₁₁α-hydroxylation, the method of adding water was investigated. When medium volume to 7L auto-bioreactor was 3.5L, adding 1.5L water and adjusting pH to 6.0 at 18h, and adding substrate at 22h, the conversion rate was increased by 5% and reached to 52.4%.