8-27: Ethanol production properties of recombinant Saccharomyces cerevisiae expressing mutated SPT15 genes

The SPT15 gene encodes the TATA-binding protein of Saccharomyces cerevisiae, which able to regulate the transcription of multiple genes. Recombinant S. cerevisiae ETS2 and ETS3 strains were constructed to express the mutated SPT15 genes and their fermentation properties were characterized in batch cultures using high glucose concentrations. In microaerobic batch cultures using a chemically defined medium with 470 g/L glucose, ETS2 and ETS3 strains showed 2.5, 3.2 and 1.3 fold increases in glucose consumption rate, ethanol production rate and ethanol yield, compared with those of the BY4741 host strain, respectively. A batch culture of ETS3 in a bioreactor containing complex medium with 300 g/L glucose resulted in 22.2 g/L dry cell mass, 98.1 g/L ethanol concentration and 1.82 g/L-hr ethanol productivity, which were about 13-16% increases relative to those of BY4741 strain. As a result, recombinant S. cerevisiae expressing the mutated SPT15 genes possessed the improved fermentation properties of cell growth and ethanol production for fuel ethanol manufacturing.

Key words: ethanol, Saccharomyces cerevisiae, SPT15, multiple gene transcription, fermentation