Cellular mechanisms contributing to multiple stress tolerance in Saccharomyces cerevisiae strains with potential use in high-temperature ethanol fermentation.
High-temperature ethanol fermentation has several benefits including a reduction in cooling cost, minimizing risk of bacterial contamination, and enabling simultaneous saccharification and fermentation. To achieve the efficient ethanol fermentation at high temperature, yeast strain that tolerates to not only high temperature but also the other stresses present during fermentation, e.g., ethanol, osmotic, and oxidative stresses, is indispensable. The C3253, C3751, and C4377 Saccharomyces cerevisiae strains, which have been previously isolated as thermotolerant yeasts, were found to be multiple stress-tolerant. In these strains, continuous expression of heat shock protein genes and intracellular trehalose accumulation were induced in response to stresses causing protein denaturation. Compared to the control strains, these multiple stress-tolerant strains displayed low intracellular reactive oxygen species levels and effective cell wall remodeling upon exposures to almost all stresses tested. In response to simultaneous multi-stress mimicking fermentation stress, cell wall remodeling and redox homeostasis seem to be the primary mechanisms required for protection against cell damage. Moreover, these strains showed better performances of ethanol production than the control strains at both optimal and high temperatures, suggesting their potential use in high-temperature ethanol fermentation.
Department of Biology, Faculty of Science, Mahidol University, Rama VI Rd, Bangkok, 10400, Thailand.|Center of Excellence on Environmental Health and Toxicology, CHE, Ministry of Education, Bangkok, Thailand.
Yasin
Y
Kitichantaropas
Department of Biotechnology, Faculty of Science, Mahidol University, Rama VI Rd, Bangkok, 10400, Thailand.
Chuenchit
C
Boonchird
Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan.
Minetaka
M
Sugiyama
Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan.
Yoshinobu
Y
Kaneko
Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan.|Department of Applied Microbial Technology, Faculty of Biotechnology and Life Science, Sojo University, 4-22-1 Ikeda, Kumamoto, 860-0082, Japan.
Satoshi
S
Harashima
Department of Biology, Faculty of Science, Mahidol University, Rama VI Rd, Bangkok, 10400, Thailand. choowong.aue@mahidol.ac.th.|Center of Excellence on Environmental Health and Toxicology, CHE, Ministry of Education, Bangkok, Thailand. choowong.aue@mahidol.ac.th.
Choowong
C
Auesukaree
Cell wall remodeling; Heat shock protein; High-temperature ethanol fermentation; Multi-stress; Redox homeostasis; Saccharomyces cerevisiae; Trehalose