NOVELTY - Expression cassette comprises nucleobase sequence i.e. xylose isomerase having 1314 nucleobases (SEQ ID NO: 1), transaldolase having 1008 nucleobases (SEQ ID NO: 5), ribose 5-phosphate isomerase having 777 nucleobases (SEQ ID NO: 7), xylulokinase having 1803 nucleobases (SEQ ID NO: 9), transketolase having 2043 nucleobases (SEQ ID NO: 11) or ribose 5-phosphate epimerase having 717 nucleobases (SEQ ID NO: 12), given in the specification. Promoter i.e. glyceraldehyde 3-phosphate dehydrogenase having 742 nucleobases (SEQ ID NO: 2) or kinase 3-phosphate having 873 nucleobases (SEQ ID NO: 6).    USE - Expression cassette for transforming eukaryotic cell, and used in micro-organism for producing biofuel, preferably ethanol (all claimed).    DETAILED DESCRIPTION - Expression cassette comprises nucleobase sequence i.e. xylose isomerase having 1314 nucleobases (SEQ ID NO: 1), transaldolase having 1008 nucleobases (SEQ ID NO: 5), ribose 5-phosphate isomerase having 777 nucleobases (SEQ ID NO: 7), xylulokinase having 1803 nucleobases (SEQ ID NO: 9), transketolase having 2043 nucleobases (SEQ ID NO: 11) or ribose 5-phosphate epimerase having 717 nucleobases (SEQ ID NO: 12), given in the specification. Promoter i.e. glyceraldehyde 3-phosphate dehydrogenase having 742 nucleobases (SEQ ID NO: 2), kinase 3-phosphate having 873 nucleobases (SEQ ID NO: 6) or alcohol dehydrogenase 1 having 702 nucleobases (SEQ ID NO: 8), and terminator i.e. glyceraldehyde 3-phosphate dehydrogenase having 305 nucleobases (SEQ ID NO: 3), alcohol dehydrogenase 1 having 236 nucleobases (SEQ ID NO: 10) or kinase 3-phosphate having 189 nucleobases (SEQ ID NO: 13), given in the specification. The nucleotide sequence is linked to the promoter and terminator. INDEPENDENT CLAIMS are included for:    (1) a method for transforming eukaryotic cell, which involves inserting expression cassette in eukaryotic cell;    (2) genetically modified micro-organism, which contains expression cassette; and    (3) a method for culturing genetically modified micro-organism for producing biofuel, which involves inoculating genetically modified micro-organism in synthetic medium containing xylose as carbon source.