YEAST STRAINS CO-EXPRESSING EXOGENOUS GLUCOAMYLASES, THE METHOD FOR OBTAINING SAID YEAST STRAINS AND THE USE THEREOF TO PRODUCE BIOETHANOL

摘要

The present invention relates to enhanced Saccharomyces cerevisiae yeast strains. The invention is characterized in that these strains co-express a gene that codes for a fungal glucoamylase and a gene that codes for the glucoamylase of Saccharomyces cerevisiae var. diastaticus. The present invention also relates to a method for obtaining these yeast strains, said method including the following steps: a) genetically modifying a yeast of Saccharomyces cerevisiae such as to make said yeast co-express a gene that codes for a fungal glucoamylase and a gene that codes for a glucoamylase of Saccharomyces cerevisiae var. diastaticus, b) culturing and fermenting the strain obtained in step a) on a dextrin medium, c) selecting the strains having fermentation kinetics at least no lower than those of the strain deposited, pursuant to the Budapest Treaty, on 9 July 2015 at the Collection Nationale de Cultures de Micro-organismes (CNCM) under number I-4999 in the same conditions. The yeast strains according to the invention are particularly of interest in the production of bioethanol.