Patent ID: 8809060

Claim:
An ethanol-tolerant yeast strain transformed with a mutated SPT15 gene, wherein the mutated SPT15 gene is selected from the group consisting of a nucleotide sequence encoding an amino acid sequence consisting of mutations at positions L76 and L175 in the amino acid sequence of wild-type Saccharomyces cerevisiae SPT15 gene; a nucleotide sequence encoding an amino acid sequence consisting of mutations at positions S42, C78, S163, and I212 in the amino acid sequence of wild-type Saccharomyces cerevisiae SPT15 gene; a nucleotide sequence encoding an amino acid sequence consisting of mutations at positions F10 and M197 in the amino acid sequence of wild-type Saccharomyces cerevisiae SPT15 gene; a nucleotide sequence encoding an amino acid sequence consisting of mutations at positions W26 and G192 in the amino acid sequence of wild-type Saccharomyces cerevisiae SPT15 gene; and a nucleotide sequence encoding an amino acid sequence consisting of mutations at positions K15, W26 and G192 in the amino acid sequence of wild-type Saccharomyces cerevisiae SPT15 gene.