Metabolic engineering for improved xylose utilisation of saccharomyces cerevisiae

A method for preparing an ethanol producing, xylose utilizing strain of Saccharomyces cerevisiae comprising genes for overexpression of xylose reductase, xylitol dehydrogenase and xylulokinase, wherein in addition to said genes, the genes for production of phosphoacetyltransferase, and acetaldehyde dehydrogenase are introduced and, overexpressed, wherein the gene encoding for phosphoacetyltransferase is cloned from a bacterium that produces ethanol or a protozoa, the gene encoding for acetaldehyde dehydrogenase is cloned from Entamoeba histolytica, and wherein the strain is deleted with regard to the gene expressing the endogenous aldehyde dehydrogenase Δald6.