Materials and methods for identifying and using yeast strains that metabolize pentose sugars in the presence of D-glucose

Patent metadata

Field	Value
Publication number	US-9469837-B2
Application number	US-201013202452-A
Country	US
Kind code	B2
Filing date	Feb 25, 2010
Priority date	Feb 25, 2009
Publication date	Oct 18, 2016
Grant date	Oct 18, 2016

Abstract

Disclosed herein are materials and methods for creating and/or isolating variants of yeasts especially variants of Saccharomyces cerevisiae that can grow on sugars other than D-glucose in the presence of amounts of 2-deoxy-glucose and or D-glucose that inhibit most strains of yeast from growing on sugars other than D-glucose. Selection media that can be used to isolate such variants include pentose sugars such as D-xylose, L-glutamine and 2-deoxy-glucose. Mutations in the Grr1 and Red genes in some strains also produce variants that can grow on sugars including the pentose D-xylose in the presence of 2-deoxy-glucose.

First claim

The invention claimed is:

1. A variant yeast comprising a strain of Saccharomyces cerevisiae that is capable of growth utilizing at least one pentose sugar as a sole carbon source in the presence of at least 0.03% wt. 2-deoxy-glucose, wherein the variant yeast is deficient in a gene product of at least one gene selected from the group consisting of GRR1, REG1, and HXK2, and wherein the strain of Saccharomyces cerevisiae is selected from the group consisting of a strain having ATCC accession number PTA-9849, and a strain having ATCC accession number PTA-9850.

2. The variant yeast according to claim 1 , wherein the strain of S. cerevisiae is haploid or diploid.

3. A method for isolating a yeast that will grow on at least one pentose sugar as a sole carbon source, the method comprising the steps of:
providing a growth medium, wherein the medium includes 2-deoxy-glucose, D-xylose and glutamine, wherein D-xylose is the sole carbon source;
inoculating the medium with at least one strain of yeast, wherein yeast of the at least one strain are deficient in a gene product of at least one gene selected from the group consisting of GRR1, REG1, and HXK2, and wherein the strain of Saccharomyces cerevisiae is selected from the group consisting of a strain having ATCC accession number PTA-9849, and a strain having ATCC accession number PTA-9850; and
isolating at least one yeast cell from the medium, wherein the yeast cell grows on D-xylose as a sole carbon source in the presence of at least about 0.03 wt. % 2-deoxy-glucose.

4. The method according to claim 3 , wherein the strain exhibits detectable growth on the medium after about 14 days.

5. The method according to claim 3 , wherein the medium includes about 2.0 wt. % xylose, and about 0.5 wt. % glutamine.

6. The method according to claim 3 , wherein the yeast is a species of Saccharomyces.

7. The method according to claim 6 , wherein the yeast is S cerevisiae.

8. The method according to claim 6 , where the S. cerevisiae is haploid.

9. A method of fermenting a sugar source, comprising the steps of: providing at least one strain of Saccharomyces cerevisiae , wherein yeast of the at least one strain of Saccharomyces cerevisiae are deficient in a gene product of at least one gene selected from the group consisting of GRR1, REG1, and HXK2, and wherein the at least one strain of Saccharomyces cerevisiae is selected from the group consisting of a strain having ATCC accession number PTA-9849, and a strain having ATCC accession number PTA-9850, and will grow on at least one pentose sugar in the presence of at least 0.03 wt. % 2-deoxy-glucose; and supplying a feed stock that includes at least one sugar; and growing said yeast strain the feed stock.

10. The method according to claim 9 , wherein the feed stock includes an amount of D-glucose sufficient to support the growth of the yeast strain in the absence of any additional sugar source.

11. The method according to claim 9 , wherein the feed stock includes a pentose sugar that can be fermented by said yeast strain.

12. The method according to claim 9 , wherein the feed stock includes a pentose sugar that can be fermented by said yeast strain and at least 0.1% 2-deoxy-glucose.

13. The method according to claim 9 , wherein the feed stock includes a fermentable hexose sugar other than D-glucose.

14. The method according to claim 13 , wherein the feed stock further includes D-glucose.

Assignees

• Goebl Mark
• Woods Cary
• Cocklin Ross
• Heyen Josh
• Univ Indiana Res & Tech Corp

Inventors

• Goebl Mark
• Woods Cary
• Cocklin Ross
• Heyen Josh

Classifications

• C12P7/00

  Preparation of oxygen-containing organic compounds · CPC title

• C12P7/06

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

• C12N1/18 Primary

  Baker's yeast; Brewer's yeast · CPC title

• C12N15/01

  Preparation of mutants without inserting foreign genetic material therein; Screening processes therefor · CPC title

• Y02E50/16

  Cross-Sectional Technologies · mapped topic