Mutant NNK1 allele and its use

Patent metadata

Field	Value
Publication number	US-9809830-B2
Application number	US-201415103916-A
Country	US
Kind code	B2
Filing date	Dec 12, 2014
Priority date	Dec 13, 2013
Publication date	Nov 7, 2017
Grant date	Nov 7, 2017

Abstract

The present invention relates to a mutant NNK1 allele, especially a mutant carrying a mutation at position of amino acid 807 of the wild type sequence. The invention relates further to the use of said mutant allele to increase the fermentation rate in yeast, preferably in Saccharomyces . The mutant allele is especially useful to increase the xylose to ethanol fermentation rate.

First claim

The invention claimed is:

1. A genetically modified xylose fermenting yeast strain, comprising a mutant DNA molecule that corresponds to a mutant nitrogen network kinase 1 (NNK1) allele and encodes a mutant kinase protein carrying a mutation at position 807 of a wild type kinase protein the amino acid sequence of which is 95% identical to SEQ ID NO: 2, wherein the yeast strain is not Saccharomyces cerevisiae strain GS1.11-26 and wherein the mutant increases the xylose-to-ethanol fermentation rate as compared to the wild type.

2. The yeast strain according to claim 1 , which has an increased fermentation rate as compared to the fermentation rate of an isogenic yeast strain not comprising said mutant DNA molecule when the fermentation is carried out under the same conditions.

3. The yeast strain according to claim 1 , wherein said mutation in the protein is a serine to asparagine replacement.

4. The yeast strain according to claim 1 , which is a member of a yeast genus selected from the group consisting of Saccharomyces, Zygosaccharomyces, Brettanomyces and Kluyverocmyces.

5. The yeast strain according to claim 4 , which is a member of the species Saccharomyces cerevisiae.

6. The yeast strain according to claim 5 , wherein said DNA molecule encodes a mutant protein the amino acid sequence of which is SEQ ID NO:4.

7. A process for producing ethanol comprising a step or steps in which the yeast strain of claim 1 ferments a carbohydrate to ethanol.

8. The process according to claim 7 , wherein the carbohydrate comprises xylose.

9. The yeast strain according to claim 2 , wherein said mutation in the protein is a serine to asparagine replacement.

10. The yeast strain according go claim 2 , which is a member of a yeast genus selected from the group consisting of Saccharomyces, Zygosaccharomyces, Brettanomyces and Kluyverocmyces.

11. The yeast strain according to claim 10 , which is a member of the species Saccharomyces cerevisiae.

12. The yeast strain according to claim 11 , wherein said DNA molecule encodes a protein the amino acid sequence of which is SEQ ID NO:4.

13. A process for producing ethanol comprising fermenting a carbohydrate to ethanol employing the yeast strain of claim 2 .

14. A process for producing ethanol comprising fermenting a carbohydrate to ethanol employing the yeast strain of claim 3 .

15. A process for producing ethanol comprising fermenting a carbohydrate to ethanol employing the yeast strain of claim 4 .

16. A process for producing ethanol comprising fermenting a carbohydrate to ethanol employing the yeast strain of claim 5 .

17. A process for producing ethanol comprising fermenting a carbohydrate to ethanol employing the yeast strain of claim 11 .

18. A process for producing ethanol comprising fermenting a carbohydrate to ethanol employing the yeast strain of claim 12 .

Assignees

• Vib Vzw
• Univ Leuven Kath

Inventors

• Thevelein Johan
• Demeke Mekonnen
• Foulquié Moreno Maria Remedios

Classifications

• C12N9/12 Primary

  transferring phosphorus containing groups, e.g. kinases (2.7) · CPC title

• Y02E50/17

  Cross-Sectional Technologies · mapped topic

• Y02E50/16

  Cross-Sectional Technologies · mapped topic

• C12P7/10

  substrate containing cellulosic material · CPC title

• C12P7/06 Primary

  Ethanol, i.e. non-beverage · CPC title