Biotechnological optimization of microorganisms for the 1,2-dehydrogenation of steroids
The present invention concerns a genetically modified bacterium and to its industrial application, in particular in the 1,2-dehydrogenation of steroids.
1 . A genetically modified bacterium wherein expression of a gene encoding a 20-beta-hydroxysteroid dehydrogenase (20β-HSDH) is reduced or suppressed compared to a corresponding unmodified bacterium, wherein the corresponding unmodified bacterium has Δ1-dehydrogenase activity and 20-β-hydroxysteroid dehydrogenase activity, and wherein the gene encoding a 20β-HSDH has at least 90% identity to the nucleic acid sequence set forth in SEQ ID NO: 1.
2 . The genetically modified bacterium according to claim 1 , wherein the gene encoding a 20β-HSDH is inactivated or deleted.
3 . The genetically modified bacterium according to claim 1 , wherein the gene encoding a 20β-HSDH is mutated.
4 . The genetically modified bacterium according to claim 1 , wherein the gene encoding a 20β-HSDH is truncated.
5 . The genetically modified bacterium according to claim 1 , wherein the bacterium is from the family Nocardioidaceae.
6 . The genetically modified bacterium according to claim 1 , wherein the genetically modified bacterium has Δ1-dehydrogenase activity, but has reduced or is devoid of 20-β-hydroxysteroid dehydrogenase activity compared to the unmodified bacterium.
7 . The genetically modified bacterium according to claim 1 , wherein the gene encoding a 20β-HSDH is at least 95% identical to the nucleic acid sequence set forth in SEQ ID NO: 1.
8 . The genetically modified bacterium according to claim 1 , wherein the gene encoding a 20β-HSDH comprises the nucleic acid sequence set forth in SEQ ID NO: 1.
9 . A method for production of a genetically modified bacterium according to claim 1 comprising:
a) providing a bacterium which has Δ1-dehydrogenase activity and 20-β-hydroxysteroid dehydrogenase activity; and
b) inactivating or deleting the gene encoding a 20β-HSDH.
10 . The method according to claim 9 , wherein the gene encoding a 20β-HSDH comprises the nucleic acid sequence set forth in SEQ ID NO: 1.
11 . A method for the production of 1,2-dehydrogenated steroid comprising:
a) providing a steroid which is not 1,2-dehydrogenated;
b) contacting said steroid which is not 1,2-dehydrogenated with a bacterium according to claim 1 or an extract thereof under conditions sufficient to obtain 1,2-dehydrogenated steroid.
12 . The method according to claim 11 , wherein the steroid which is not 1,2-dehydrogenated is a corticosteroid.
13 . The method according to claim 11 , wherein said steroid which is not 1,2-dehydrogenated is hydrocortisone and said method is for the production of prednisolone.
14 . The method according to claim 11 , wherein said method further comprises recovering and purifying said 1,2-dehydrogenated steroid.
15 . The method according to claim 14 , which does not comprise a step of elimination of 20 β-dehydrogenated steroid.
16 . The method according to claim 11 , which further comprises formulating the 1,2-dehydrogenated steroid into a pharmaceutical composition.
17 . The method according to claim 11 , wherein said extract has Δ1-dehydrogenase activity.
18 . The method according to claim 11 , wherein said extract is obtained by cell-lysis of the bacterium.
19 . The method according to claim 18 , wherein the cell-lysis product is fractionated in order to concentrate Δ1-dehydrogenase activity or to facilitate purification of Δ1-dehydrogenase activity.
20 . The method according to claim 11 , wherein the gene encoding a 20β-HSDH comprises the nucleic acid sequence set forth in SEQ ID NO: 1.