Abstract
Composition of the fermentation medium influenced both the rate of progesterone hydroxylation and the type of the resulting metabolite by Aspergillus niger 12Y. Dimethyl sulphoxide was a limiting factor for progesterone hydroxylation but it did not affect the types of enzymic activities. No extracellular hydroxylases catalyzing the transformation of progesterone were produced. Mycelial sporulation catalyzed the productivity of hydroxylases and/or the rate of progesterone transformation. Productivity of hydroxylases was more inducive with mycelia grown in shaken than in surface culture. Contrary to 11β-hydroxylase, the inducibility of 11α-hydroxylase was unaffected by the pH value at the time of induction. 11α-Hydroxy, l7α-hydroxy, and 21-hydroxy derivatives of progesterone induced the formation of only the corresponding hydroxylases. On the other hand, 11β-hydroxy-progesterone induced both 11β- and 21-hydroxylases. Quantities higher than 3g of induced moist mycelium and concentrations of substrate higher than 10mg in 70ml of the reaction mixture were found to be limiting factors for progesterone transformation. The in vivo 11α-hydroxylase and 11β-hydroxylase were most active within pH range of 4.0 to 6.0, while 21-hydroxylase showed a maximal activity at pH 4.0.
