Glucose transport mutants for production of biomaterial
A method is disclosed for restoring a Glu + phenotype to a PTS − /Glu − bacterial cell which was originally capable of utilizing a phosphotransferase transport system (PTS) for carbohydrate transport. Bacterial cells comprising the Glu + phenotype have modified endogenous chromosomal regulatory regions which are operably linked to polynucleotides encoding galactose permeases and glucokinases.
1. A method of increasing carbon flow into a metabolic pathway of a PTS − /Glu − bacterial host cell originally capable of utilizing a phosphotransferase transport system (PTS) for carbohydrate transport comprising,
a) modifying an endogenous chromosomal regulatory region which is operably linked to a nucleic acid encoding a glucose assimilation protein in a PTS − /Glu − host cell by transforming the PTS − /Glu − host cell with a DNA construct comprising a promoter and DNA flanking sequences corresponding to upstream (5′) regions of the glucose assimilation protein;
b) allowing integration of the DNA construct to restore a Glu+ phenotype; and
c) culturing the transformed host cell under suitable culture conditions,
wherein carbon flow into a metabolic pathway of the transformed host cell is increased compared to carbon flow into the corresponding metabolic pathway in a PTS bacterial host cell cultured under essentially the same culture conditions.
2. The method according to claim 1 , wherein the promoter is a non-host cell promoter.
3. The method according to claim 1 , wherein the promoter is a modified endogenous promoter.
4. The method according to claim 1 , wherein the glucose assimilation protein is a glucose transporter.
5. The method according to claim 4 , wherein the glucose transporter is a galactose permease obtained from E. coli or a glucose transporter having at least 80% sequence identity thereto.
6. The method according to claim 1 , wherein the glucose assimilation protein is a phosphorylating protein.
7. The method according to claim 6 , wherein the phosphorylating protein is a glucokinase.
8. The method according to claim 5 , further comprising modifying an endogenous chromosomal regulatory region which is operably linked to a nucleic acid encoding a glucokinase in the PTS − /Glu − host cell by transforming the PTS − /Glu − host cell with a second DNA construct comprising a promoter and DNA flanking sequences corresponding to upstream (5′) regions of the glucokinase.
9. The method of claim 1 , wherein the bacterial host cell is selected from the group consisting of E. coli cells, Bacillus cells and Pantoea cells.
10. The method according to claim 1 , wherein the PTS − /Glu − host cell is obtained from a PTS cell by deletion of one or more genes selected from the group consisting of ptsI, ptsH and crr.
11. The method according to claim 1 , further comprising transforming the PTS − /Glu + host cell with a polynucleotide encoding a protein selected from the group consisting of a transketolase, a transaldolase, and a phosphoenolpyruvate synthase.
12. The method according to claim 1 , further comprising transforming the PTS − /Glu + host cell with a polynucleotide encoding at least one enzyme selected from the group consisting of DAHP synthase, DHQ synthase, DHQ dehydratase, shikimate dehydrogenase, shikimate kinase EPSP synthase and chorismate synthase.
13. A bacterial cell, wherein the bacterial cell has increased carbon flow into a metabolic pathway, comprising:
a PTS − bacterial cell incapable of utilizing a phosphotransferase transport system (PTS) for carbohydrate transport, whererin the PTS − bacterial cell comprises a modified endogenous chromosomal regulatory region which is operably linked to a nucleic acid that encodes a glucose assimilation protein,
wherein carbon flow into the metabolic pathway is increased compared to carbon flow into the corresponding metabolic pathway in a PTS bacterial cell cultured under essentially the same culture conditions.
14. A method of increasing carbon flow into a metabolic pathway of a PTS − /Glu − bacterial host cell originally capable of utilizing a phosphotransferase transport system (PTS) for carbohydrate transport comprising,
a) modifying an endogenous chromosomal regulatory region which is operably linked to a nucleic acid encoding a galactose permease in a PTS − /Glu − host cell by transforming the PTS − /Glu − host cell with a first DNA construct comprising a promoter and DNA flanking sequences corresponding to upstream (5′) regions of the galactose permease;
b) modifying an endogenous chromosomal regulatory region which is operably linked to a nucleic acid encoding a glucokinase in the PTS − /Glu − host cell by transforming the PTS − /Glu − host cell with a second DNA construct comprising a promoter and DNA flanking sequences corresponding to upstream (5′) regions of the glucokinase;
c) allowing integration of the first and the second DNA constructs, wherein the first DNA construct replaces an endogenous promoter of the nucleic acid encoding the galactose permease and the second DNA construct replaces an endogenous promoter of the nucleic acid encoding the glucokinase wherein both the galactose permease and the glucokinase are expressed in the host cell and wherein said expression results in an increase in carbon flow into a metabolic pathway of the transformed host cell compared to carbon flow into the corresponding metabolic pathway in an unaltered PTS − /Glu − bacterial cell.
15. The method according to claim 14 , wherein the bacterial host cell is selected from the group consisting of E. coli cells, Bacillus cells and Pantoea cells.
16. The method according to claim 14 , wherein the metabolic pathway is the common aromatic pathway.
17. The method according to claim 14 , further comprising transforming the PTS − /Glu − host cell with a polynucleotide encoding a protein selected from the group consisting of a transketolase, a transaldolase and a phosphoenolpyruvate synthase.
18. A method for increasing the growth rate of a PTS − /Glu − bacterial host cell originally capable of utilizing a phosphotransferase transport system (PTS) for carbohydrate transport comprising,
a) modifying an endogenous chromosomal regulatory region which is operably linked to a nucleic acid encoding a galactose permease in a PTS − /Glu − host cell by transforming the PTS − /Glu − host cell with a first DNA construct comprising an exogenous promoter and DNA flanking sequences corresponding to (5′) upstream region of the galactose permease;
b) modifying an endogenous regulatory region which is operably linked to a nucleic acid encoding a glucokinase in the PTS − /Glu − host cell by transforming the PTS − /Glu − host cell with a second DNA construct comprising an exogenous promoter and DNA flanking sequences corresponding to upstream (5′) regions of the glucokinase;
c) allowing integration of the first and the second DNA constructs, wherein the first DNA construct replaces the endogenous promoter of the nucleic acid encoding the galactose permease and the second DNA construct replaces the endogenous promoter of the nucleic acid encoding the glucokinase;
d) culturing the transformed bacterial host cell under suitable conditions; and
e) allowing expression of the galactose permease and the glucokinase from the modified regulatory regions to obtain an altered bacterial cell having an increased specific growth rate compared to the specific growth rate of a corresponding unaltered PTS bacterial host cell cultured under essentially the same culture conditions.
19. A bacterial cell, wherein the bacterial cell has an increased growth rate, comprising:
a) a PTS − bacterial cell incapable of utilizing a phosphotransferase transport system (PTS) for carbohydrate transport,
b) a modified endogenous chromosomal regulatory region which is operably linked to a nucleic acid that encodes a galactose permease, and
c) a modified endogenous chromosomal regulatory region which is operably linked to a nucleic acid that encodes a glucokinase,
wherein the growth rate is increased compared to the growth rate of a corresponding PTS bacterial cell cultured under essentially the same culture conditions.
20. The bacterial cell of claim 19 , wherein said bacterial cell is a Pantoea cell.
21. The bacterial cell of claim 19 , wherein said bacterial cell is an E. coli cell.
22. The method according to claim 18 further comprising transforming the selected bacterial host cell with a polynucleotide encoding a protein selected from the group consisting of a transketolase, a transaldolase and a phosphoenolpyruvate synthase.
23. The cell according to claim 13 , wherein the modified regulatory region is a non-host cell promoter.
24. The cell according to claim 13 , wherein the modified regulatory region is a modified endogenous promoter.
25. The cell according to claim 13 , wherein the glucose assimilation protein is a glucose transporter.
26. The cell according to claim 25 , wherein the glucose transporter is a galactose permease obtained from E. coli or a glucose transporter having at least 80% sequence identity thereto.
27. The cell according to claim 13 , wherein the glucose assimilation protein is a phosphorylating protein.
28. The cell according to claim 27 , wherein the phosphorylating protein is a glucokinase.
29. The cell according to claim 25 , further comprising a modified endogenous chromosomal regulatory region which is operably linked to a nucleic acid that encodes a glucokinase.
30. The cell according to claim 13 , wherein the bacterial host cell is selected from the group consisting of E. coli cells, Bacillus cells and Pantoea cells.
31. The cell according to claim 13 , wherein the PTS − bacterial cell is obtained from a PTS cell by deletion of one or more genes selected from the group consisting of ptsI, ptsH and crr.
32. The cell according to claim 13 , further comprising a polynucleotide that encodes a protein selected from the group consisting of a transketolase, a transaldolase, and a phosphoenolpyruvate synthase.
33. The cell according to claim 13 , further comprising a polynucleotide that encodes at least one enzyme selected from the group consisting of DAHP synthase, DHQ synthase, DHQ dehydratase, shikimate dehydrogenase, shikimate kinase EPSP synthase and chorismate synthase.
34. The cell according to claim 19 , wherein the modified regulatory region is a non-host cell promoter.
35. The cell according to claim 19 , wherein the modified regulatory region is a modified endogenous promoter.
36. The cell according to claim 19 , wherein the glucose assimilation protein is a glucose transporter.
37. The cell according to claim 36 , wherein the glucose transporter is a galactose permease obtained from E. coli or a glucose transporter having at least 80% sequence identity thereto.
38. The cell according to claim 19 , wherein the glucose assimilation protein is a phosphorylating protein.
39. The cell according to claim 38 , wherein the phosphorylating protein is a glucokinase.
40. The cell according to claim 37 , further comprising a modified endogenous chromosomal regulatory region which is operably linked to a nucleic acid that encodes a glucokinase.
41. The cell according to claim 19 , wherein the bacterial host cell is a Bacillus cell.
42. The cell according to claim 19 , wherein the PTS − bacterial cell is obtained from a PTS cell by deletion of one or more genes selected from the group consisting of ptsI, ptsH and crr.
43. The cell according to claim 19 , further comprising a polynucleotide that encodes a protein selected from the group consisting of a transketolase, a transaldolase, and a phosphoenolpyruvate synthase.
44. The cell according to claim 19 , further comprising a polynucleotide that encodes at least one enzyme selected from the group consisting of DAHP synthase, DHQ synthase, DHQ dehydratase, shikimate dehydrogenase, shikimate kinase EPSP synthase and chorismate synthase.