The present invention relates to the field of the methods for obtaining yeast strains producing ethanol, of the thereby produced strains, and of the industrial production of ethanol from said strains.
More particularly, the present invention describes in its most general aspect, a method for preparing yeasts from Saccharomyces cerevisiae strains by integration into the genome of the yeast of at least one gene coding for xylose isomerase and of at least one gene coding for xylitol dehydrogenase.
The strain of the invention is useful for producing ethanol from a medium comprising at least one pentose, preferably xylose or a xylose and arabinose mixture.