Fermentation efficiency using yeast containing prions
Genetically modified microorganisms useful in fermentation and methods of using such microorganisms are provided. Such microorganisms contain a [GAR+] prion or are modified to contain a [GAR+] prion. Exemplary microorganisms include yeast such as S. cerevisiae . The microorganisms can be further modified to convert xylose and/or arabinose. Methods of fermentation using such microorganisms exhibit improved fermentation efficiency and improved microorganism viability.
1. A method of producing ethanol from a multi-sugar feedstock having a blend of 5-carbon sugars and 6-carbon sugars, the method comprising inoculating the multi-sugar feedstock with [GAR+] Saccharomyces cerevisiae strain, which contains a C5 sugar metabolic pathway to ferment xylose and/or arabinose, and fermenting the feedstock, wherein:
the [GAR+] Saccharomyces cerevisiae strain utilizes 5-carbon and 6-carbon sugars simultaneously during fermentation of the multi-sugar feedstock and ethanol is produced from the feedstock.
2. The method of claim 1 , wherein the [GAR+] Saccharomyces cerevisiae is UCD932.
3. The method of claim 1 , wherein the feedstock is red liquor waste.
4. The method of claim 1 wherein the [GAR+] Saccharomyces cerevisiae strain is genetically modified to comprise the C5 sugar metabolic pathway.
5. The method of claim 4 , wherein the [GAR+] Saccharomyces cerevisiae strain is further modified to express saccharification enzymes.
6. The method of claim 5 , wherein the saccharification enzymes are selected from cellulases, beta-glucosidases, xylanases, and LPMOs.
7. The method of claim 4 , wherein the 5-carbon sugar is xylose and the 6-carbon sugar is glucose and both are used simultaneously during fermentation.
8. The method of claim 1 wherein ethanol production is improved relative to fermentation using [GAR−] yeast.
9. The method of claim 1 , wherein the [GAR+] Saccharomyces cerevisiae strain is modified to express at least one of cellulases, beta-glucosidases, xylanases, and LPMOs.
10. The method of claim 1 , wherein the [GAR+] Saccharomyces cerevisiae strain is genetically modified to use xylose and/or arabinose.
11. The method of claim 1 , wherein efficiency of conversion of non-glucose C6 sugars is improved relative to fermentation using [GAR−] yeast.
12. The method of claim 10 , wherein the non-glucose C6 sugars are selected from mannose and galactose.
13. The method of claim 1 , wherein the feedstock is lignocellulosic feedstock.
14. The method of claim 1 , wherein the [GAR+] Saccharomyces cerevisiae strain is obtained by introducing a [GAR+] prion into a Saccharomyces cerevisiae strain.
15. The method of claim 1 , wherein the [GAR+] Saccharomyces cerevisiae strain viability is improved relative to fermentation using [GAR−] yeast.
16. The method of claim 1 , wherein fermentation using the [GAR+] Saccharomyces cerevisiae strain produces increased ethanol yield relative to fermentation using [GAR−] yeast.
17. The method of claim 1 , wherein fermentation rate of the [GAR+] Saccharomyces cerevisiae strain is improved relative to fermentation using [GAR−] yeast.
18. The method of claim 1 , wherein conversion of mannose and galactose is improved relative to fermentation using [GAR−] yeast.
19. A method of producing ethanol from a multi-sugar feedstock having a blend of 5-carbon sugars and 6-carbon sugars, the method comprising inoculating the multi-sugar feedstock with a [GAR+] Saccharomyces cerevisiae strain, which contains a C5 sugar metabolic pathway to ferment xylose and/or arabinose, and fermenting the feedstock, wherein:
the [GAR+] Saccharomyces cerevisiae strain utilizes the two or more sugars simultaneously during fermentation of the multi-sugar feedstock, ethanol is produced from the feedstock, and efficiency of conversion of non-glucose C6 sugars is improved relative to fermentation using [GAR−] yeast.
20. A method of producing ethanol from a multi-sugar feedstock having a blend of 5-carbon sugars and 6-carbon sugars, the method comprising inoculating the multi-sugar feedstock with a [GAR+] Saccharomyces cerevisiae strain, genetically modified to use xylose and/or arabinose, and fermenting the feedstock, wherein:
the [GAR+] Saccharomyces cerevisiae strain utilizes the two or more sugars simultaneously during fermentation of the multi-sugar feedstock and ethanol is produced from the feedstock.