Genes related to xylose fermentation and methods of using same for enhanced biofuel production
The present invention provides isolated gene sequences involved in xylose fermentation and related recombinant yeast which are useful in methods of enhanced biofuel production, particularly ethanol production. Methods of bioengineering recombinant yeast useful for biofuel production are also provided.
1. A recombinant nucleic acid vector comprising a heterologous promoter operably linked to a nucleic acid encoding a polypeptide having aldo/keto reductase activity and comprising an amino acid sequence that is at least 95% identical to the amino acid sequence of the aldo/keto reductase polypeptide encoded by the nucleotide sequence of SEQ ID NO: 3.
2. A recombinant yeast transformed with the recombinant nucleic acid vector of claim 1 .
3. The recombinant yeast of claim 2 , wherein the recombinant yeast is of the genus Saccharomyces.
4. The recombinant yeast of claim 2 , wherein the recombinant yeast is of the species Saccharomyces cerevisiae.
5. The recombinant yeast of claim 2 , further comprising XYL1, XYL2 and XYL3 genes.
6. The recombinant yeast of claim 2 , wherein the recombinant nucleic acid vector is an extrachromosomal vector stably maintained in the recombinant yeast.
7. The recombinant yeast of claim 2 , wherein the recombinant nucleic acid vector is integrated into the chromosome of the recombinant yeast.
8. The recombinant yeast of claim 5 , wherein the recombinant yeast is of the species Saccharomyces cerevisiae and the XYL1, XYL2 and XYL3 genes are from Pichia stipitis.
9. A method for producing ethanol by fermentation of xylose by a yeast, comprising: (a) culturing the recombinant yeast of claim 2 under ethanol-producing conditions comprising xylose; and (b) isolating ethanol produced by said recombinant yeast.
10. The method of claim 9 , wherein the recombinant yeast is Saccharomyces cerevisiae.
11. The method of claim 9 , wherein the recombinant yeast further comprises XYL1, XYL2, and XYL3 genes.
12. The method of claim 9 , wherein the nucleic acid encoding the polypeptide having aldo/keto reductase activity comprises the nucleotide sequence of SEQ ID NO: 3.
13. A recombinant Saccharomyces cerevisiae comprising (a) a nucleic acid encoding a polypeptide having aldo/keto reductase activity, wherein the polypeptide having aldo/keto reductase activity comprises an amino acid sequence that is at least 95% identical to the amino acid sequence of the aldo/keto reductase polypeptide encoded by the nucleotide sequence of SEQ ID NO: 3, wherein the nucleic acid is operably linked to a heterologous promoter; and (b) XYL1, XYL2 and XYL3 genes from Pichia stipitis.
14. The recombinant Saccharomyces cerevisiae of claim 13 , wherein the nucleic acid encoding the polypeptide having aldo/keto reductase activity comprises the nucleotide sequence of SEQ ID NO: 3.