Superior thermotolerance of Saccharomyces cerevisiae for efficient bioethanol fermentation can be achieved by overexpression of RSP5 ubiquitin ligase

Characterization and gene expression profiles of thermotolerant Saccharomyces cerevisiae isolates from Thai fruits

“…Furthermore, since the molecular mechanisms conferring thermotolerance are complicated and controlled by multiple genes (29), only increased expression of genes functioning in the prevention of protein denaturation (e.g., HSPs and trehalose) may be insufficient to allow growth and ethanol production at high temperatures. Supporting this idea, our group recently found that two additional genes correlated with thermotolerance of C3723 were CDC19 encoding pyruvate kinase (involved in ATP production) and RSP5 encoding ubiquitin ligase (involved in protein degradation) (30,31). These findings indicated that additional cellular functions may also be correlated with high temperature growth and that further studies are needed to gain a better understanding of the molecular mechanisms conferring yeast thermotolerance.…”

Understanding the Mechanism of Thermotolerance Distinct From Heat Shock Response Through Proteomic Analysis of Industrial Strains of Saccharomyces cerevisiae

“…However, due to the increasing demand of producing larger and cheaper ethanol volumes worldwide, S. cerevisiae is further challenged with new process requirements. Specifically, yeasts with higher thermotolerance are needed to fulfill fermentation at temperature above 40°C which will largely reduce cooling costs and help preventing contamination (2,3). High-temperature cultivation will also benefit a simultaneous saccharification and fermentation process, given that the current compromise between the optimal fermentation temperature (30 -35°C) and saccharification temperature (Ͼ50°C) considerably limits the rate and efficiency of enzymatic hydrolysis (2,4).…”

“…Specifically, yeasts with higher thermotolerance are needed to fulfill fermentation at temperature above 40°C which will largely reduce cooling costs and help preventing contamination (2,3). High-temperature cultivation will also benefit a simultaneous saccharification and fermentation process, given that the current compromise between the optimal fermentation temperature (30 -35°C) and saccharification temperature (Ͼ50°C) considerably limits the rate and efficiency of enzymatic hydrolysis (2,4). Starting from a robust industrial strain of S. cerevisiae, our laboratory has acquired a new diploid strain ScY01 with more superior thermotolerance through the strategy of adaptive evolution.…”

Biomass for Energy Country Specific Show Case Studies

“…This protein is also involved in the pathways responsible for the regulation of chromatin function and ultimately controls gene expression under limited nutrient conditions [75]. Most recently, Shahsavarani et al [76] also demonstrated that overexpression of RSP5 encoding ubiquitin ligase improved the ability of S. cerevisiae to tolerate high temperatures. An increase in the ubiquitin ligase, which was observed in this study by the high expression level of rsp during ethanol fermentation at high temperature, might regulate the transcription of some genes and induce the heat stress response through the ubiquitination process.…”

“…However, most studies on H 2 production on biowaste have been performed using mixed cultures under mesophilic conditions [74,75]. Only a few studies have focused on mixed thermophilic consortia [76,77]. It has been demonstrated that the extreme thermophile C. saccharolyticus can produce H 2 from mono-and disaccharides [78].…”