Processing Genome Edited, Lignin-Modified Sugarcane Biomass with a Xylose Fermenting Yeast Strain Drastically Elevates Biofuel Production

Sugarcane is a prime feedstock for commercial production of bioethanol. Utilizing both sucrose and cell wall bound sugars for fermentation will enhance the biofuel yield per unit area. The recalcitrant structure of lignocellulosic biomass is a major barrier for efficient biomass-to-ethanol conversion. Co-editing of more than 100 copies of the caffeic acid O-methyltransferase (COMT) gene resulted in modified lignin biosynthesis and elevated the saccharification efficiency more than 40% compared to un-modified sugarcane biomass. The combination of feedstock engineering via genome editing of the lignin synthesis pathway of sugarcane and co-fermentation of xylose and glucose with a recombinant xylose utilizing yeast strain allowed to produce 148% more ethanol compared to that of the un-modified biomass and control strain. The lignin reduced biomass led to a substantially increased release of fermentable sugars (glucose and xylose). The engineered yeast strain efficiently co-utilized glucose and xylose for fermentation, elevating ethanol yields. This strategy will significantly improve the economic feasibility of producing biofuels from lignocellulosic biomass.