Expression of Aspergillus awamori Glucoamylase Gene in an Industrial Strain of Saccharomyces cerevisiae

To construct an amylolytic industrial strain of Saccharomyces cerevisiae, the glucoamylase cDNA gene (GAl) from Aspergillus awamori was expressed under the control of the alcohol dehydrogenase gene promoter (ADC1p) and integrated into the chromosomes of industrial S. cerevisiae. An integrative cassette lacking bacterial ampicillin resistance gene but containing the GA1 gene, sequences of Ty1 retrotransposon as target sites for homologous recombination and S. cerevisiae aureobasidin A resistance gene (AUR1-C) as the selection marker was constructed to obtain a strain eligible for commercial use. Industrial S. cerevisiae transformed with this 15-integrative cassette efficiently secreted glucoamylase into the medium and grew on starch as the sole carbon source. The transformants were mitotically stable for 100 generations in nonselective medium.