Compositions and methods for 3-hydroxypropionic acid production
The present application discloses genetically modified yeast cells comprising an active 3-HP fermentation pathway, and the use of these cells to produce 3-HP.
1. A transformed yeast cell selected from I. orientalis, C. lambica , and S. bulderi , comprising an active 3-HP fermentation pathway, wherein the pathway comprises an exogenous gene that is not present in the native form of the cell which encodes for an aspartate 1-decarboxylase (ADC) wherein the cell is capable of growing at a pH of less than 4 in media containing 75 g/L or greater 3-HP.
2. The transformed yeast cell of claim 1 , wherein the exogenous ADC gene is operatively linked to one or more exogenous regulatory elements.
3. The transformed yeast cell of claim 1 , wherein said cell further comprises one or more deletions or disruptions of a native gene selected from PDC, ADH, GAL6, CYB2A, CYB2B, GPD, GPP, ALD, and PCK genes.
4. The transformed yeast cell of claim 3 , wherein one or more of the deletions or disruptions results from insertion of the exogenous ADC gene.
5. The transformed yeast cell of claim 1 , wherein the cell is a 3-HP-resistant yeast cell.
6. The transformed yeast cell of claim 1 , wherein the cell has undergone mutation and/or selection, such that the mutated and/or selected cell possess a higher degree of resistance to 3-HP than a wild-type cell of the same species.
7. The transformed yeast cell of claim 6 , wherein the cell has undergone mutation and/or selection before being genetically modified with the exogenous ADC gene.
8. The transformed yeast cell of claim 6 , wherein the cell has undergone selection in the presence of lactic acid or 3-HP.
9. The transformed yeast cell of claim 8 , wherein the selection is chemostat selection.
10. The transformed yeast cell of claim 1 , wherein the yeast cell is an I. orientalis yeast cell.
11. The transformed yeast cell of claim 1 , wherein the yeast cell is an I. orientalis CNB1 yeast cell.
12. The transformed yeast cell of claim 11 , wherein the modified yeast cell is unable to ferment pentose sugars.
13. The transformed yeast cell of claim 1 , wherein the yeast cell is a C. lambica yeast cell.
14. The transformed yeast cell of claim 1 , wherein the yeast cell is an S. bulderi yeast cell.
15. The transformed yeast cell of claim 1 , further comprising an exogenous PYC gene.
16. The transformed yeast cell of claim 1 , further comprising an exogenous AAT gene.
17. The transformed yeast cell of claim 1 , further comprising an exogenous BAAT gene or an exogenous gabT gene.
18. The transformed yeast cell of claim 17 , wherein said BAAT gene or gabT gene is a BAAT gene that is also a gabT gene.
19. The transformed yeast cell of claim 1 , further comprising an exogenous 3-HPDH gene.
20. The transformed yeast cell of claim 10 , further comprising an exogenous 3-HPDH gene.
21. The transformed yeast cell of claim 19 , wherein the 3-HPDH gene is also a HIBADH gene.
22. The transformed yeast cell of claim 19 , wherein the 3-HPDH gene is also a 4-hydroxybutyrate dehydrogenase gene.
23. The transformed yeast cell of claim 1 , further comprising an exogenous PPC gene.
24. A method of producing 3-HP comprising:
(i) culturing the transformed yeast cell of claim 1 in the presence of medium comprising at least one carbon source; and
(ii) isolating 3-HP from the culture.
25. The method of claim 24 , wherein said carbon source is selected from glucose, xylose, arabinose, sucrose, fructose, cellulose, glucose oligomers, and glycerol.
26. The method of claim 24 , wherein the medium is at a pH of less than 5.
27. The method of claim 24 , wherein the transformed yeast cell is an I. orientalis CNB1 yeast cell.
28. The method of claim 27 , wherein the transformed yeast cell is unable to ferment pentose sugars.
29. The method of claim 24 , wherein the transformed yeast cell is an I. orientalis yeast cell.
30. The method of claim 24 , wherein the transformed yeast cell is a C. lambica yeast cell.
31. The method of claim 24 , wherein the transformed yeast cell is an S. bulderi yeast cell.
32. The method of claim 29 , wherein the transformed yeast cell further comprises an exogenous 3-HPDH gene.