Genetically modified trehalose-expressing yeasts and fermentation processes using such genetically modified yeasts
AssigneeCargill, Incorporated
InventorsPeter Alan Jauert, Gregory Michael Poynter, Brian J. Rush
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Abstract
The present invention relates to genetically engineered yeasts having a heterologous trehalase gene and fermentation processes for using such yeasts. The yeasts can express trehalase in a quantity sufficient to convert significant amounts of trehalose to glucose, thereby improving the yield of the product in a fermentation, and/or reducing or eliminating the need to add exogenous trehalase to the fermentation. The yeasts can also include other heterologous genes for expressing enzymes useful for improving yield and/or for reducing or eliminating the need to add exogenous enzymes to the fermentation.
Claims20
A genetically modified yeast comprising an exogenous nucleic acid encoding a heterologous trehalase polypeptide, wherein the trehalase polypeptide comprises (i) a sequence at least 90% identical to SEQ ID NO:83;
- (ii) a sequence at least 90% identical to SEQ ID NO:84;
- (iii) a sequence at least 90% identical to SEQ ID NO:85;
- or (iv) combinations thereof, and
- wherein the yeast is capable of producing ethanol when the yeast is present in a fermentation medium comprising trehalose and the yeast secretes the trehalase polypeptide in an amount sufficient to reduce the trehalose content of a fermentation broth to less than 2 g/L when the ethanol titer is at least 110 g/L.
The yeast of 16, wherein the trehalase polypeptide comprises a sequence at least 94% identical to SEQ ID NO:
- 84.
A genetically modified yeast comprising an exogenous nucleic acid sequence encoding a heterologous trehalase polypeptide comprising a sequence at least 80% identical to SEQ ID NO:88,
- wherein the yeast is capable of producing ethanol when the yeast is present in a fermentation medium comprising trehalose and the yeast secretes the trehalase polypeptide in an amount sufficient to reduce the trehalose content of a fermentation broth to less than 2 g/L when the ethanol titer is at least 110 g/L.
Dependencies are inferred from the claim text.