Yeasts modified to use carbon dioxide
The invention relates to yeast cells modified to express a functional type I RuBisCO enzyme, and a class II phosphoribulokinase. The expression of these enzymes recreates a Calvin cycle in said yeasts in order to enable the yeasts to use carbon dioxide.
1. A transformed yeast cell, characterized in that it contains:
a) an expression cassette containing a sequence encoding the RbcL subunit of a bacterial form I RuBisCO enzyme, under the transcriptional control of a suitable promoter;
b) an expression cassette containing a sequence encoding the RbcS subunit of said RuBisCO enzyme, under the transcriptional control of a suitable promoter;
c) an expression cassette containing a sequence encoding the specific chaperone RbcX of said RuBisCO enzyme, under the transcriptional control of a suitable promoter;
d) an expression cassette containing a sequence encoding a general bacterial chaperone GroES, under the transcriptional control of a suitable promoter; and
e) an expression cassette containing a sequence encoding a general bacterial chaperone GroEL, under the transcriptional control of a suitable promoter, wherein the RbcX originates from a different bacteria than the GroES and the GroEL.
2. The transformed yeast cell according to claim 1 , characterized in that the GroES and GroEL originate-from E. coli.
3. The transformed yeast cell according to claim 1 , characterized in that the chaperone RbcX is a cyanobacterial chaperone.
4. The transformed yeast cell according to claim 1 , characterized in that GroES and GroEL come from a bacterium that does not naturally express a RuBisCO complex.
5. The transformed yeast cell according to claim 1 , characterized in that the three expression cassettes mentioned in points c), d), and e) of claim 1 form a continuous block of genetic information.
6. The transformed yeast cell according to claim 1 , characterized in that the expression cassettes mentioned in points c), d), and e) of claim 1 are carried by a single episomal genetic element.
7. The transformed yeast cell according to claim 1 , characterized in that said yeast is Saccharomyces cerevisiae.
8. The transformed yeast cell according to claim 1 , characterized in that the bacterial form I RuBisCO enzyme is a cyanobacterial RuBisCO enzyme.
9. The transformed yeast cell according to claim 8 , characterized in that said cyanobacterium belongs to the genus Synechococcus.
10. The transformed yeast cell according to claim 1 , characterized in that it further contains an expression cassette containing a sequence encoding a phosphoribulokinase (PRK) under the transcriptional control of a suitable promoter.
11. The transformed yeast cell according to claim 10 , characterized in that said PRK is a class II PRK.
12. The transformed yeast cell according to claim 11 , characterized in that said class II PRK is selected from PRKs from Spinacia oleracea, Euglena gracilis , or Synechococcus elongatus.
13. The transformed yeast cell according to claim 10 , characterized in that the promoter controlling transcription of the sequence encoding the PRK is an inducible promoter.
14. The transformed yeast cell according to claim 2 , characterized in that the chaperone RbcX is a cyanobacterial chaperone.
15. The transformed yeast cell according to claim 3 , characterized in that the GroES and GroEL come from a bacterium that does not naturally express a RuBisCO complex.
16. The transformed yeast cell according to claim 2 , characterized in that the three expression cassettes mentioned in points c), d), and e) of claim 1 form a continuous block of genetic information.
17. The transformed yeast cell according to claim 3 , characterized in that the three expression cassettes mentioned in points c), d), and e) of claim 1 form a continuous block of genetic information.
18. The transformed yeast cell according to claim 4 , characterized in that the three expression cassettes mentioned in points c), d), and e) of claim 1 form a continuous block of genetic information.
19. The transformed yeast cell according to claim 2 , characterized in that the expression cassettes mentioned in points c), d), and e) of claim 1 are carried by a single episomal genetic element.
20. The transformed yeast cell according to claim 2 , characterized in that the chaperone RbcX is a cyanobacterial chaperone.
21. The transformed yeast cell according to claim 20 , characterized in that the GroES and GroEL come from a bacterium that does not naturally express a RuBisCO complex.
22. The transformed yeast cell according to claim 20 , characterized in that the three expression cassettes mentioned in points c), d), and e) of claim 1 form a continuous block of genetic information.
23. The transformed yeast cell according to claim 1 , further containing:
f) an expression cassette containing a sequence encoding a class II PRK under the transcriptional control of a suitable promoter,
wherein the bacterial form I RuBisCO enzyme is a cyanobacterial RuBisCO enzyme and the GroES and GroEL are from E. coli.