Xylose isomerase genes and their use in fermentation of pentose sugars
AssigneeDsm IP Assets B.V.
InventorsAloysius Wilhelmus Rudolphus Hubertus Teunissen, Johannes Adrianus Maria De Bont
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Abstract
The present invention relates to eukaryotic cells which have the ability to isomerize xylose directly into xylulose. The cells have acquired this ability by transformation with nucleotide sequences coding for a xylose isomerase that has one or more specific sequence elements typical for isomerases having the ability of functional expression in yeasts, such as e.g. xylose isomerases obtainable from a bacterium of the genera Clostridium and Fusobacterium or a tunicate form the genus Ciona. The cell preferably is a yeast or a filamentous fungus, more preferably a yeast is capable of anaerobic alcoholic fermentation.
Claims23
A yeast cell comprising a nucleic acid construct comprising a heterologous nucleic acid with a nucleotide sequence encoding a polypeptide that has xylose isomerase activity, the expression of which confers on, or increases in, the yeast cell the ability to directly isomerize xylose into xylulose, wherein the amino acid sequence of the polypeptide is at least 93% identical to SEQ ID NO:1 and comprises one or more conservative amino acid substitutions;
- wherein the one or more conservative amino acid substitutions is selected from the group consisting of valine to leucine or isoleucine, phenyalanine to tyrosine, lysine to arginine, and asparagine to glutamine.
A eukaryotic cell comprising:
- (a) a heterologous nucleic acid encoding the polypeptide of SEQ ID NO:
- 1;
- or
- (b) a heterologous nucleic acid encoding a polypeptide having xylose isomerase activity, wherein said polypeptide comprises all of SEQ ID NO:
- 1 except for one amino acid substitution selected from the group consisting of valine to leucine or isoleucine, phenylalanine to tyrosine, lysine to arginine, alanine to valine, and asparagine to glutamine.
Dependencies are inferred from the claim text.