Methods for regulating nitrogen metabolism during the production of ethanol from corn by metabolically engineered yeast strains
AssigneeLallemand Hungary Liquidity Management LLC
InventorsAaron Argyros, Trisha Barrett
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Abstract
The present invention provides for a mechanism to reduce glycerol production and increase nitrogen utilization and ethanol production of recombinant microorganisms. One aspect of this invention relates to strains of S. cerevisiae with reduced glycerol productivity that get a kinetic benefit from higher nitrogen concentration without sacrificing ethanol yield. A second aspect of the invention relates to—metabolic modifications resulting in altered transport and/or intracellular metabolism of nitrogen sources present in corn mash.
Claims21
-215. (canceled)
A recombinant yeast comprising:
- a) at least one engineered genetic modification that leads to the down-regulation of an enzyme in a glycerol-production pathway;
- and,
- b) at least one engineered genetic modification that leads to the up-regulation or down-regulation of an enzyme in a nitrogen-assimilation pathway;
- wherein the down-regulated enzyme in the glycerol-production pathway is selected from the group consisting of glycerol-3-phosphate dehydrogenase 1 (Gpd1) (EC 1.1.1.8), glycerol-3-phosphate dehydrogenase 2 (Gpd2) (EC 1.1.1.8), a glycerol-3-phosphate phosphatase 1 (Gpp1) (EC 3.1.3.21), and glycerol-3-phosphate phosphatase 2 (Gpp2) (EC 3.1.3.21));
- wherein the down-regulated enzyme in the nitrogen-assimilation pathway is glutamate dehydrogenase (Gdh) (EC 1.4.1.4);
- or
- wherein the up-regulated enzyme in the nitrogen-assimilation pathway is at least one enzyme selected from the group consisting of glutamate dehydrogenase (Gdh) (EC 1.4.1.2), glutamate synthase (Glt) (EC 1.4.1.14), and glutamine synthase (Gln) (EC 6.3.1.2);
- an ammonium transporter;
- a urea-amido lyase (EC 6.3.4.6);
- and a urea transporter.
Dependencies are inferred from the claim text.