Abstract: The present invention relates to a novel selective synthesis of 9?-hydroxy-steroid derivatives of the general formula (I) (I)—wherein the meaning of -A-A?- is —CH2—CH2— or —CH?CH— group—by the bioconversion of compounds of the general formula (II) (II) wherein the meaning of -A-A?- is —CH2—CH2— or —CH?CH— group—by using Nocardia farcinica bacterium strain, deposition number of which is NCAIM (P)—B 001342, as hydroxylating microorganism in the bioconversion.

Abstract: The present invention relates to a novel selective synthesis of 9?-hydroxy-steroid derivatives of the general formula (I) (I)—wherein the meaning of -A-A?- is —CH2—CH2— or —CH?CH— group—by the bioconversion of compounds of the general formula (II) (II) wherein the meaning of -A-A?- is —CH2—CH2— or —CH?CH— group—by using Nocardia farcinica bacterium strain, deposition number of which is NCAIM (P)-B 001342, as hydroxylating microorganism in the bioconversion.

Abstract: The invention relates to a process for the production of compounds of general formula (I), wherein R1 is a —NH-tert-butyl group or a 4-methyl-piperidino group, by bioconversion of compounds of general formula (II), wherein R1 is as described above, using a biocatalyst having steroid-&Dgr;1-dehydrogenase enzyme activity, wherein the activity of the enzyme needed for the bioconversion is produced by induction.

Abstract: The invention relates to a process for the production of compounds of general formula (I), wherein R1 is a —NH-tert-butyl group or a 4-methyl-piperidino group, by bioconversion of compounds of general formula (II), wherein R1 is as described above, using a biocatalyst having steroid-&Dgr;1-dehydrogenase enzyme activity, wherein the activity of the enzyme needed for the bioconversion is produced by induction.

Abstract: The invention relates to a process for the production of 9.alpha.-hydroxy-4-androstene-3,17-dione from natural sterols of plant or animal origin or from mixtures thereof by the submerged aerobic fermentation of an enzyme-deficient, sterol-de-grading microorganism in a nutrient medium containing utilizable carbon and nitrogen sources as well as mineral salts, and by isolating the product formed, which comprises transforming the sterol or sterol mixture with the culture of a 1,2-steroid-dehydrogenase deficient strain of new Mycobacterium roseum species which is able to degrade the side-chain of natural sterols, preferably with Mycobacterium roseum sp. nov. 1108/1 deposited at the National Collection of Agricultural and Industrial Microorganisms, Budapest, Hungary under the number NCAIM B (P) 000339, and by isolating and purifying the 9.alpha.-hydroxy-4-androstene-3,17-dione obtained.

Abstract: Microbiological conversions of cyclodextrins are intensified by adding to the reaction mixture 0.2 to 3 moles of .alpha.-, .beta.- or .gamma.-cyclodextrin or an optical mixture thereof pro mole of the steroid substrate, before, at the beginning or during the conversion. The cyclodextrin if desired, can be removed after the reaction. In this way the reaction velocity can be increased, the reaction time is reduced, the substrate concentration in the solution, i.e. its solubility is increased or the so called product inhibition may be avoided. In certain cases of more alternatives the desired reaction can be catalyzed and in this manner the selectivity is increased.