Yeast strain with improved ability to ferment xylose in the presence of acetic acid

摘要

The present invention relates to a method for selecting yeast strains having an improved ability to ferment pentoses, preferably xylose, in the presence of non-dissociated forms of organic acids, preferably acetic acid. At least one yeast strain capable of fermenting the pentose is continuously cultured in the following two media: first growth comprising the pentose as the sole carbon source and the organic acid in an undissociated form Medium; a second growth medium that does not contain the organic acid in non-dissociated form and contains another carbon source as a sole carbon source, preferably glucose. Continuous culture in at least the two growth media is repeated at least twice in the presence of increasing concentrations of organic acids in non-dissociated form.