In various aspects and embodiments, the invention provides a nucleic acid molecule comprising a nucleotide sequence encoding a 7?-hydroxysteroid dehydrogenase (7?-HSDH) mutant that catalyzes at least the stereospecific enzymatic reduction of a 7-ketosteroid to the corresponding 7-hydroxysteroid, wherein the mutant has, compared to the wildtype 7?-HSDH of SEQ ID NO:2, a decreased substrate inhibition and/or an altered cofactor usage, and the mutant has, in comparison with the wildtype 7?-HSDH of SEQ ID NO:2, 1 to 15 amino acid additions, substitutions, deletions and/or inversions in the sequence motif VMVGRRE corresponding to positions 36 to 42 of SEQ ID NO:2.

In various aspects and embodiments, the invention provides a nucleic acid molecule comprising a nucleotide sequence encoding a 7?-hydroxysteroid dehydrogenase (7?-HSDH) mutant that catalyzes at least the stereospecific enzymatic reduction of a 7-ketosteroid to the corresponding 7-hydroxysteroid, wherein the mutant has, compared to the wildtype 7?-HSDH of SEQ ID NO:2, a decreased substrate inhibition and/or an altered cofactor usage, and the mutant has, in comparison with the wildtype 7?-HSDH of SEQ ID NO:2, 1 to 15 amino acid additions, substitutions, deletions and/or inversions in the sequence motif VMVGRRE corresponding to positions 36 to 42 of SEQ ID NO:2.

A process for the enzymatic regeneration of the redox cofactors NAD.sup.+/NADH and NADP.sup.+/NADPH in a one-pot reaction, wherein, as a result of at least two further enzymatically catalyzed redox reactions proceeding in the same reaction batch (product-forming reactions), one of the two redox cofactors accumulates in its reduced form and, respectively, the other one in its oxidized form, characterized in that a) in the regeneration reaction which reconverts the reduced cofactor into its original oxidized form, oxygen or a compound of general formula R.sub.1C(O)COOH is reduced, and b) in the regeneration reaction which reconverts the oxidized cofactor into its original reduced form, a compound of general formula R.sub.2CH(OH)R.sub.3 is oxidized and wherein R.sub.1, R.sub.2 and R.sub.3 in the compounds have different meanings.

A process for the enzymatic regeneration of the redox cofactors NAD.sup.+/NADH and NADP.sup.+/NADPH in a one-pot reaction, wherein, as a result of at least two further enzymatically catalyzed redox reactions proceeding in the same reaction batch (product-forming reactions), one of the two redox cofactors accumulates in its reduced form and, respectively, the other one in its oxidized form, characterized in that a) in the regeneration reaction which reconverts the reduced cofactor into its original oxidized form, oxygen or a compound of general formula R.sub.1C(O)COOH is reduced, and b) in the regeneration reaction which reconverts the oxidized cofactor into its original reduced form, a compound of general formula R.sub.2CH(OH)R.sub.3 is oxidized and wherein R.sub.1, R.sub.2 and R.sub.3 in the compounds have different meanings.

The present invention provides a hydroxyacyl-coenzyme A dehydrogenase gene, an acyl-coenzyme A thiolase gene, genetically engineered strains and a use thereof. The hydroxyacyl-coenzyme A dehydrogenase gene encodes a protein (i) or (ii) as follows: (i) having an amino acid sequence according to SEQ ID NO 2; (ii) derived by substituting, deleting or inserting one or more amino acids in the amino acid sequence defined by (i) and having the same function as that of the protein of (i). The present invention constructs genetically engineered Mycobacterium strains lacking of a hydroxyacyl-coenzyme A dehydrogenase gene or an acyl-coenzyme A thiolase gene, which are used in the preparation of steroidal compounds, such as 1,4-BNA, 4-BNA, 9-OH-BNA, etc. Further, the invention improves the production efficiency and product quality of steroidal drug, improves the utilization of drug precursors, reduces the production costs, and provides the advantages of mild reaction conditions, environmentally friendly, and high economic and social benefits.

The present invention provides a hydroxyacyl-coenzyme A dehydrogenase gene, an acyl-coenzyme A thiolase gene, genetically engineered strains and a use thereof. The hydroxyacyl-coenzyme A dehydrogenase gene encodes a protein (i) or (ii) as follows: (i) having an amino acid sequence according to SEQ ID NO 2; (ii) derived by substituting, deleting or inserting one or more amino acids in the amino acid sequence defined by (i) and having the same function as that of the protein of (i). The present invention constructs genetically engineered Mycobacterium strains lacking of a hydroxyacyl-coenzyme A dehydrogenase gene or an acyl-coenzyme A thiolase gene, which are used in the preparation of steroidal compounds, such as 1,4-BNA, 4-BNA, 9-OH-BNA, etc. Further, the invention improves the production efficiency and product quality of steroidal drug, improves the utilization of drug precursors, reduces the production costs, and provides the advantages of mild reaction conditions, environmentally friendly, and high economic and social benefits.

The present invention relates to a method of producing ginsenoside 20(S)Rg3 or 20(S)Rh2 using a novel ginsenoside glycosidase in order to obtain ginsenoside 20(S)Rg3 or 20(S)Rh2 with high efficiency and high purity. According to the production method of the present invention, a large amount of 20(S)Rg3 or 20(S)Rh2, which is a minor form of rare ginsenoside present in very small amounts in ginseng or processed ginseng products, may be safely and efficiently produced. In particular, the method according to the present invention has an advantag5e in that it may produce a large amount of 20(S)Rg3 or 20(S)Rh2 for industrial applications, since the process is very simple and the production efficiency is very high.

The present invention relates to a method of producing ginsenoside 20(S)Rg3 or 20(S)Rh2 using a novel ginsenoside glycosidase in order to obtain ginsenoside 20(S)Rg3 or 20(S)Rh2 with high efficiency and high purity. According to the production method of the present invention, a large amount of 20(S)Rg3 or 20(S)Rh2, which is a minor form of rare ginsenoside present in very small amounts in ginseng or processed ginseng products, may be safely and efficiently produced. In particular, the method according to the present invention has an advantag5e in that it may produce a large amount of 20(S)Rg3 or 20(S)Rh2 for industrial applications, since the process is very simple and the production efficiency is very high.

The present invention provides a method for extracting lipids from microorganisms without using organic solvent as an extraction solvent. In particular, the present invention provides a method for extracting lipids from microorganisms by lysing cells and removing water soluble compound and/or materials by washing the lysed cell mixtures with aqueous washing solutions until a substantially non-emulsified lipid is obtained.

The present invention provides a method for extracting lipids from microorganisms without using organic solvent as an extraction solvent. In particular, the present invention provides a method for extracting lipids from microorganisms by lysing cells and removing water soluble compound and/or materials by washing the lysed cell mixtures with aqueous washing solutions until a substantially non-emulsified lipid is obtained.