Engineering thermotolerant microbial strains via TrRCC1 overexpression for efficient bioethanol production

• Overexpression of TrRCC1 gene enhances thermotolerance in T. reesei and S. cerevisiae . • Homologous overexpression of TrRCC1 in T. reesei increases cellulase production by 2.5-fold. • Ethanol production by S. cerevisiae increases by 21%, achieving 44.1 g/L during SSF of corn stover. • TrRCC1 is a novel target for bioethanol production under high-temperature stress conditions. Efficient conversion of corn stover to bioethanol via simultaneous saccharification and fermentation (SSF) is a promising strategy for sustainable biofuel production. A major current barrier to this process is the limited thermotolerance of Saccharomyces cerevisiae , which hampers its performance under the high-temperature conditions required for efficient SSF. In this study, we identified TrRCC1 , a gene from Trichoderma reesei , as a candidate for improving microbial stress resistance. Overexpression of TrRCC1 in both T. reesei Rut C30 and S. cerevisiae BY4741 significantly enhanced thermotolerance. In T. reesei Rut C30, TrRCC1 overexpression improved heat resistance and increased cellulase production by 2.5-fold compared to the wild-type strain. In S. cerevisiae BY4741, TrRCC1 overexpression resulted in enhanced thermotolerance and a 21.8% increase in ethanol production during SSF of corn stover. The ethanol concentration achieved in the SSF process with TrRCC1 -overexpressing S. cerevisiae was 44.1 g/L, which was a notable improvement over control strain production. These findings highlight the potential of TrRCC1 as a key gene for engineering microbial strains with improved stress resistance to enhance the efficiency of bioethanol production from lignocellulosic biomass.