| Summary: | This study aimed to select thermotolerant yeast for bioethanol production from cellulose-rich corncob (CRC) residue. An effective yeast strain was identified as <i>Saccharomyces cerevisiae</i> TC-5. Bioethanol production from CRC residue via separate hydrolysis and fermentation (SHF), simultaneous saccharification and fermentation (SSF), and prehydrolysis-SSF (pre-SSF) using this strain were examined at 35–42 °C compared with the use of commercial <i>S. cerevisiae</i>. Temperatures up to 40 °C did not affect ethanol production by TC-5. The ethanol concentration obtained via the commercial <i>S. cerevisiae</i> decreased with increasing temperatures. The highest bioethanol concentrations obtained via SHF, SSF, and pre-SSF at 35–40 °C of strain TC-5 were not significantly different (20.13–21.64 g/L). The SSF process, with the highest ethanol productivity (0.291 g/L/h), was chosen to study the effect of solid loading at 40 °C. A CRC level of 12.5% (<i>w</i>/<i>v</i>) via fed-batch SSF resulted in the highest ethanol concentrations of 38.23 g/L. Thereafter, bioethanol production via fed-batch SSF with 12.5% (<i>w</i>/<i>v</i>) CRC was performed in 5-L bioreactor. The maximum ethanol concentration and ethanol productivity values were 31.96 g/L and 0.222 g/L/h, respectively. The thermotolerant <i>S. cerevisiae</i> TC-5 is promising yeast for bioethanol production under elevated temperatures via SSF and the use of second-generation substrates.
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