Multiplex genome editing to construct cellulase engineered Saccharomyces cerevisiae for ethanol production from cellulosic biomass

The production of biofuels from cellulosic biomass has emerged as an appealing alternative to fossil fuels. However, the recalcitrance of cellulose poses a challenge to converting it into fermentable sugars, impeding the economic viability of bioethanol production. S. cerevisiae, the primary species employed for industrial ethanol production, exhibits stress tolerance and the ability to ferment diverse sugars from various feedstocks. Nonetheless, the production of cellulase enzymes in S. cerevisiae remains limited. To tackle this hurdle, multiplex genome editing technologies offer a promising avenue for engineering recombinant cellulolytic S. cerevisiae strains, thus enabling ethanol production from cellulosic biomass. This review provides an overview of distinct multiplex genome editing techniques employed in the engineering of such strains. These encompass homologous recombination-mediated multiplex genome editing, mega nuclease-mediated multiplex genome editing, TALEN-mediated multiplex genome editing, CRISPR/Cas-mediated multiplex genome editing, multiplex genome editing involving multiple sgRNA expression frames, multiplex genome editing through sgRNA or crRNA arrays, and multiplex genomic integration targeting repetitive sequences. Furthermore, this review delves into the potential of cellulase-engineered S. cerevisiae for ethanol production. The successful development of recombinant cellulolytic S. cerevisiae strains holds the promise of revolutionizing the biofuel industry. This transformation would entail cost reductions in ethanol production, alongside enhancing industry sustainability, consequently diminishing our reliance on fossil fuels. The availability of cellulase-engineered S. cerevisiae strains for ethanol production from cellulosic biomass stands to curtail our dependency on fossil fuels and markedly alleviate the impacts of climate change.