Thermotolerant yeasts and their biotechnological applications

Most known yeasts are mesophilic organisms, with optimal growth at 28-30°C. However, a few species, notably Ogataea polymorpha and Kluyveromyces marxianus, can grow at temperatures around 50°C. Their thermotolerance is of both fundamental and applied interest, offering advantages for high-temperature bioprocesses. Notably, cultivation at elevated temperatures facilitates simultaneous saccharification and fermentation (SSF) of starchy and lignocellulosic substrates, reduces sterility requirements, lowers distillation costs, and enhances the rates of biochemical reactions. These features make thermotolerant yeasts attractive platforms for producing biofuels, proteins, and other valuable compounds. Despite their potential, the underlying mechanisms of thermotolerance in these species remain underexplored. Herein, we systematically review the molecular, cellular, and metabolic mechanisms underlying yeast thermotolerance and discuss their implications for high-temperature industrial biotechnology.