XYLOSE ISOMERASE GENES AND THEIR USE IN FERMENTATION OF PENTOSE SUGARS

摘要

The present invention relates to eukaryotic cells which have the ability to isomerise 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.

主权项

1. A eukaryotic microbial cell comprising nucleotide sequences the expression of which confers on, or increases in, the cell the ability to directly isomerize xylose into xylulose, which nucleotide sequence encodes a polypeptide with xylose isomerase enzymatic activity, which polypeptide comprises an amino acid sequence comprising one or more of the following amino acid sequence elements:
(a) a methionine at position 91; (b) amino acid sequence TGIKLL at positions 134-139; (c) a phenylalanine residue at position 230; (d) amino acid sequence FK at position 264-265; (e) amino acid sequence TLAGH at positions 274-278; (f) amino acid sequence RYASF at positions 387-391; (g) a glycine at position 394; or, (h) an alanine at position 431; wherein the polypeptide does not comprise an amino acid sequence with more than 95% sequence identity with one of SEQ ID NO:3, SEQ ID NO:4, SEQ ID NO:5, SEQ ID NO:6 or SEQ ID NO:7.