A simple, highly effective method for lignin extraction from biomass is reported using PILs which can easily be distilled/recovered.

With a diverse and widely distributed global resource base, woody biomass is a compelling organic feedstock for conversion to renewable liquid fuels. In California, woody biomass comprises the largest fraction of underutilized biomass available for biofuel production, but conversion to fuels is challenged both by recalcitrance to deconstruction and by toxicity towards downstream saccharification and fermentation due to organic acids and phenolic compounds generated during pre-treatment. In this study, we optimize pretreatment and scale-up of an integrated one-pot process for deconstruction of California woody biomass using the ionic liquid cholinium lysinate [Ch][Lys] as a pretreatment solvent. By evaluating the impact of solids loading, solids removal, yeast acclimatization, fermentation temperature, fermentation pH, and nutrient supplementation on final ethanol yields and titers, we achieve nearly full conversion of both glucose and xylose to ethanol with commercial C5-utilizing Saccharomyces cerevisiae. We then demonstrate process scalability in a 680 L pilot-scale fermentation, achieving >80 % deconstruction efficiency, >90 % fermentation efficiency, 27.7 g/L ethanol titer, and >80 % ethanol distillation efficiency from the ILcontaining hydrolysate post-fermentation. This fully integrated process requires no intermediate separations and no intermediate detoxification of 1 the hydrolysate. Using an integrated biorefinery model, current performance results in a minimum ethanol selling price of $8.8/gge. Reducing enzyme loading along with other minor process improvements can reduce the ethanol selling price to $3/gge. This study is the largest-scale demonstration of ionic liquid pretreatment and biofuel conversion known to date, and the overall biomass-to-ethanol efficiencies are the highest reported to date for any ionic liquid-based biomass to biofuel conversion.

Systematic approach for predicting lignin extraction and studying mechanistic effects using computational chemistry and experimental correlations.