초록
<P>The application of high-potential thermotolerant yeasts is a key factor for successful ethanol production at high temperatures. Two hundred and thirty-four yeast isolates from Greater Mekong Subregion (GMS) countries, i.e., Thailand, The Lao People's Democratic Republic (Lao PDR) and Vietnam were obtained. Five thermotolerant yeasts, designated <I>Saccharomyces cerevisiae</I> KKU-VN8, KKU-VN20, and KKU-VN27, <I>Pichia kudriavzevii</I> KKU-TH33 and <I>P. kudriavzevii</I> KKU-TH43, demonstrated high temperature and ethanol tolerance levels up to 45 °C and 13% (v/v), respectively. All five strains produced higher ethanol concentrations and exhibited greater productivities and yields than the industrial strain <I>S. cerevisiae</I> TISTR5606 during high-temperature fermentation at 40 °C and 43 °C. <I>S. cerevisiae</I> KKU-VN8 demonstrated the best performance for ethanol production from glucose at 37 °C with an ethanol concentration of 72.69 g/L, a productivity of 1.59 g/L/h and a theoretical ethanol yield of 86.27%. The optimal conditions for ethanol production of <I>S. cerevisiae</I> KKU-VN8 from sweet sorghum juice (SSJ) at 40 °C were achieved using the Box–Behnken experimental design (BBD). The maximal ethanol concentration obtained during fermentation was 89.32 g/L, with a productivity of 2.48 g/L/h and a theoretical ethanol yield of 96.32%. Thus, the newly isolated thermotolerant <I>S. cerevisiae</I> KKU-VN8 exhibits a great potential for commercial-scale ethanol production in the future.</P>