Increasing NADPH availability for methionine production
View Patent ↗The present invention is related to a microorganism for the production of methionine, wherein said microorganism is modified to enhance the transhydrogenase activity of PntAB. In a preferred aspect of the invention, the activity of the transhydrogenase UdhA is attenuated in said microorganisms. The invention also related to a method for producing methionine by fermentation.
1. A microorganism modified for an improved production of methionine, wherein said microorganism is modified to enhance transhydrogenase activity of PntAB by overexpressing the genes encoding PntAB.
2. The microorganism of claim 1 , wherein said microorganism is modified to attenuate activity of transhydrogenase UdhA by deleting the gene encoding UdhA.
3. The microorganism of claim 1 , wherein said microorganism is modified to increase one carbon metabolism by enhancing at least one of the following activities:
a. activity of methylenetetrahydrofolate reductase, MetF;
b. activity of glycine cleavage complex, GcvTHP and Lpd;
c. activity of serine hydroxymethyltransferase, GlyA; and/or
d. activity of methyltransferase, MetH or MetE.
4. The microorganism of claim 3 , wherein said activity of MetF is enhanced by overexpressing the metF gene and/or by optimizing its translation by using a RNA stabiliser.
5. The microorganism of claim 4 , wherein said metF gene is under control of a strong promoter comprising at least one Ptrc family promoter.
6. The microorganism of claim 1 , wherein expression of at least one of the following genes is increased: cysP, cysU, cysW, cysA, cysM, cysI, cysJ, cysH, cysE, serA, serB, serC, metA allele with reduced feed-back sensitivity, thrA or thrA allele with reduced feed-back sensitivity.
7. The microorganism of claim 6 , wherein at least one of said genes is under control of an inducible promoter.
8. The microorganism of claim 1 , wherein expression of the gene coding for pyruvate carboxylase is enhanced.
9. The microorganism of claim 1 , wherein expression of at least one of the following genes of said microorganism is attenuated: pykA, pykF, purU, yncA or metJ.
10. The microorganism of claim 1 , wherein said microorganism is selected from Enterobacteriaceae and Corynebacteriaceae.
11. The microorganism of claim 10 , wherein said microorganism is selected from Escherichia, Klebsiella and Corynebacterium.
12. The microorganism of claim 2 , wherein said microorganism is modified to increase one carbon metabolism by enhancing at least one of the following activities:
a. the activity of methylenetetrahydrofolate reductase, MetF;
b. activity of glycine cleavage complex, GcvTHP and Lpd;
c. activity of serine hydroxymethyltransferase, GlyA; and/or
d. activity of methyltransferase, MetH or MetE.
13. The microorganism of claim 3 , wherein expression of at least one of the following genes is increased: cysP, cysU, cysW, cysA, cysM, cysI, cysJ, cysH, cysE, serA, serB, serC, metA allele with reduced feed-back sensitivity, thrA or thrA allele with reduced feed-back sensitivity.
14. The microorganism of claim 2 , wherein expression of the gene coding for pyruvate carboxylase is enhanced.
15. The microorganism of claim 2 , wherein expression of at least one the following genes of the microorganism is attenuated: pykA, pykF, purU, yncA or metJ.
16. The microorganism of claim 2 , wherein said microorganism is selected from Enterobacteriaceae and Corynebacteriaceae.
17. The microorganism of claim 16 , wherein said microorganism is selected from Escherichia, Klebsiella and Corynebacterium.
18. The microorganism of claim 17 , wherein said microorganism is Escherichia coli.
19. The microorganism of claim 17 , wherein said microorganism is Corynebacterium glutamicum.