Evaluation of thermotolerant and ethanol-tolerant Saccharomyces cerevisiae as an alternative strain for bioethanol production from industrial feedstocks

Worarat Kruasuwan; Aekkachai Puseenam; Somjit Am-In; Srisakul Trakarnpaiboon; Warasirin Sornlek; Kanokarn Kocharin; Sasitorn Jindamorakot; Sutipa Tanapongpipat; Feng-Yan Bai; Niran Roongsawang

doi:10.1007/s13205-022-03436-4

Evaluation of thermotolerant and ethanol-tolerant Saccharomyces cerevisiae as an alternative strain for bioethanol production from industrial feedstocks

3 Biotech. 2023 Jan;13(1):23. doi: 10.1007/s13205-022-03436-4. Epub 2022 Dec 23.

Affiliations

¹ Microbial Cell Factory Research Team, Biorefinery and Bioproduct Technology Research Group, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, 113 Thailand Science Park, Khlong Nueng, Khlong Luang, 12120 Pathum Thani Thailand.
² Present Address: Siriraj Long-Read Laboratory (Si-LoL), Division of Medical Bioinformatics, Research Department, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, 10700 Thailand.
³ Microbial Diversity and Utilization Research Team, Thailand Bioresource Research Center, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, 113 Thailand Science Park, Khlong Nueng, Khlong Luang, 12120 Pathum Thani Thailand.
⁴ Enzyme Technology Research Team, Biorefinery and Bioproduct Technology Research Group, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, 113 Thailand Science Park, Khlong Nueng, Khlong Luang, 12120 Pathum Thani Thailand.
⁵ State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101 China.

Abstract

Despite the fact that yeast Saccharomyces cerevisiae is by far the most commonly used in ethanol fermentation, few have been reported to be resistant to high ethanol concentrations at high temperatures. Hence, in this study, 150 S. cerevisiae strains from the Thailand Bioresource Research Center (TBRC) were screened for ethanol production based on their glucose utilization capability at high temperatures. Four strains, TBRC 12149, 12150, 12151, and 12153, exhibited the most outstanding ethanol production at high temperatures in shaking-flask culture. Among these, strain TBRC 12151 demonstrated a high ethanol tolerance of up to 12% at 40 °C. Compared to industrial and laboratory strains, TBRC 12149 displayed strong sucrose fermentation capacity whereas TBRC 12153 and 12151, respectively, showed the greatest ethanol production from molasses and cassava starch hydrolysate at high temperatures in shaking-flask conditions. In 5-L batch fermentation, similarly to both industrial strains, strain TBRC 12153 yielded an ethanol concentration of 66.5 g L^-1 (58.4% theoretical yield) from molasses after 72 h at 40 °C. In contrast, strain TBRC12151 outperformed other industrial strains in cell growth and ethanol production from cassava starch hydrolysis at 40 °C with an ethanol production of 65 g L^-1 (77.7% theoretical yield) after 72 h. Thus, the thermotolerant and ethanol-tolerant S. cerevisiae TBRC 12151 displayed great potential and possible uses as an alternative strain for industrial ethanol fermentation using cassava starch hydrolysate.

Supplementary information: The online version contains supplementary material available at 10.1007/s13205-022-03436-4.

Keywords: Cassava; Ethanol; Fermentation; Molasses; Saccharomyces cerevisiae; Stress-tolerance.

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