Search

Abstract: Two ethanol-producing yeast strains, CHY1011 and CHFY0901 were isolated from soil in South Korea using an enrichment technique in a yeast peptone dextrose medium supplemented with 5% (wv−1) ethanol at 30°C. The phenotypic and physiological characteristics, as well as molecular phylogenetic analysis based on the D1/D2 domains of the large subunit (26S) rRNA gene and the internally transcribed spacer (ITS) 1+2 regions suggested that they were novel strains of Saccharomyces cerevisiae. During shaking flask cultivation, the highest ethanol productivity and theoretical yield of S. cerevisiae CHY1011 in YPD media containing 9.5% total sugars was 1.06±0.02gl−1 h−1 and 95.5±1.2%, respectively, while those for S. cerevisiae CHFY0901 were 0.97±0.03gl−1 h−1 and 91.81±2.2%, respectively. Simultaneous saccharification and fermentation for ethanol production was carried out using liquefied cassava (Manihot esculenta) starch in a 5l lab-scale jar fermenter at 32°C for 66h with an agitation speed of 2Hz. Under these conditions, S. cerevisiae CHY1011 and CHFY0901 yielded a final ethanol concentration of 89.1±0.87gl−1 and 83.8±1.11gl−1, a maximum ethanol productivity of 2.10±0.02gl−1 h−1 and 1.88±0.01gl−1 h−1, and a theoretical yield of 93.5±1.4% and 91.3±1.1%, respectively. These results suggest that S. cerevisiae CHY1011 and CHFY0901 have potential use in industrial bioethanol fermentation processes. [Copyright &y& Elsevier]