Genetically modified trehalase-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 a heterologous gene encoding a trehalase (EC 3.2.1.28) polypeptide having a sequence identity of at least 80% to at least one of the following polypeptide sequences:
- SEQ ID NO:
- 1, SEQ ID NO:
- 2, SEQ ID NO:
- 3, or SEQ ID NO:
- 87,
- 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.
A process for manufacturing ethanol comprising:
- fermenting a medium using a genetically modified yeast, wherein the yeast comprises a heterologous trehalase gene encoding a trehalase (EC 3.2.1.28) polypeptide having a sequence identity of at least 80% to at least one of the following polypeptide sequences:
- SEQ ID NO:
- 1, SEQ ID NO:
- 2, SEQ ID NO:
- 3, or SEQ ID NO:
- 87,
- wherein the ethanol titer is at least 105 g/L as measured 36 h after inoculation and the trehalose content of the fermentation broth at the end of fermentation is less than 2 g/L.
Dependencies are inferred from the claim text.