DEVELOPMENT OF MICROBIAL PLATFORMS CAPABLE OF CO-FERMENTING NON-CONVENTIONAL SUBSTRATES FOR ENHANCED PRODUCTION OF VALUE-ADDED CHEMICALS

Our project goal is to design heterologous metabolic pathways in engineered stress-tolerant yeast Issatchenkiaorientalis for the efficient conversion of biomass hydrolysates into bioproducts. Our central hypothesis is that simultaneous co-utilization of non-glucose carbon sources in agricultural and pectin-rich hydrolysates will enhance fermentation rates and target bioproduct productivities, promoting consolidated bioprocessing (CBP). This hypothesis was formulated on the basis of previous studies showing that the heterologous fermentation pathways of non-glucose sugars were successfully integrated into one Saccharomycescerevisiae strain using the CRISPR/Cas9 system for high-efficiency multiplex genome editing. The engineered strains produced ethanol with a substantially higher yield and productivity than the control strains, resulting in the unique synergistic effects of pathway co-expression. We propose to achieve our project goal by pursuing the following two objectives:I. Develop a stress-tolerant yeast I. orientalis platform for the simultaneous co-utilization of non-glucose carbon sources.II. Validate the effect of multiplex metabolic pathways on bioproducts in an engineered I. orientalis platform.