Genetically-engineered mycobacterium strain and a use thereof in the preparation of steroidal compounds

A genetically-engineered Mycobacterium strain, characterized in that the genetically-engineered Mycobacterium strain is a Mycobacteria which lacks of acyl-CoA dehydrogenase genes fadE31, fadE32 and fadE33;

• wherein the acyl-CoA dehydrogenase gene fadE31 encodes a protein (i) or (ii) as follows:
• (i) having the amino acid sequence according to SEQ ID NO 4;
• (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);
• wherein the acyl-CoA dehydrogenase gene fadE32 encodes a protein (iii) or (iv) as follows:
• (iii) having the amino acid sequence according to SEQ ID NO 6;
• (iv) derived by substituting, deleting or inserting one or more amino acids in the amino acid sequence defined by (iii) and having the same function as that of the protein of (iii);
• and
• wherein the acyl-CoA dehydrogenase gene fadE33 encodes a protein (v) or (vi) as follows:
• (v) having the amino acid sequence according to SEQ ID NO 8;
• (vi) derived by substituting, deleting or inserting one or more amino acids in the amino acid sequence defined by (v) and having the same function as that of the protein of (v),
• wherein said proteins (ii), (iv) and (vi) have at least 75% sequence identity to SEQ ID NOs 4, 6, and 8, respectively.