Construction of an amylolytic yeast by multiple integration of the Aspergillus awamori glucoamylase gene into a Saccharomyces cerevisiae chromosome

Raw starch fermentation to ethanol by an industrial distiller’s yeast strain of Saccharomyces cerevisiae expressing glucoamylase and α-amylase genes

“…Transformant ATCC 9763/YIpdSGSAd (secreting the glucoamylase encoded for by ADC1p-GAM1 and the a-amylase encoded for by ADC1p-AMY) evidenced similar a-amylase and glucoamylase activities to those of ATCC 9763/YIpdAGSAd (secreting the glucoamylase encoded for by ADC1p-GA1 and the a-amylase encoded for by ADC1p-AMY) (Kim et al 2010). The co-expression of GAM1 with significant debranching activity (a-1,6 activity) has been shown to result in the complete hydrolysis of starch (de Moraes et al 1995), whereas the GA1-encoded glucoamylase can degrade raw starch despite its relatively low activity toward a-1,6 glycosidic bonds (Lin et al 1998;Sun et al 2010). …”

“…A genetically-manipulated S. cerevisiae that could synthesize and secrete amylolytic enzymes might prove useful for the economically important processes mentioned above (de Moraes et al 1995;Marin et al 2001;Shigechi et al 2004). Many genes of filamentous fungi and yeasts that encode for amylolytic enzymes have been expressed in S. cerevisiae (Lin et al 1998;Kim et al 2010). For efficient ethanol production, recombinant S. cerevisiae that co-expresses glucoamylase and a-amylase require both high amylolytic activity and stable expression during direct ethanol fermentation from starch.…”

Direct utilization of purple sweet potato by sake yeasts to produce an anthocyanin-rich alcoholic beverage

“…1). The fragments (7.4 and 6.1 kb) harboring the GAM1 gene cassette and the AMY gene cassette flanked by the 18S rDNA sequences were then integrated into the 18S rDNA sequences dispersed throughout the sake yeast genome to construct amylolytic sake yeasts (Lin et al 1998;Nieto et al 1999). The double rDNA system generates a smaller unneeded fragment (5.1 kb) that was eliminated before transformation (Fig.…”

“…To alleviate these costly and complex processes, recombinant S. cerevisiae strains capable of expressing starch-hydrolyzing enzymes have been developed (Dohmen et al 1990;Lin et al 1998;Kim et al 2010). However, the development of an efficient starchfermenting S. cerevisiae strain that secretes amylolytic enzymes is still needed (Kim et al 2011).…”

Construction of a direct starch-fermenting industrial strain of Saccharomyces cerevisiae producing glucoamylase, α-amylase and debranching enzyme

“…In this study, a direct and efficient starchfermenting industrial polyploid yeast strain was produced by multiple integrations of the GA1, AMY and GAM1 genes. The results presented here may lead to the development of various industrial strains of S. cerevisiae for the production of commercially important products, including ethanol, from starch in a one-step process (Lin et al 1998;Eksteen et al 2002;Shigechi et al 2004). …”