Green solvents in biomass delignification for fuels and chemicals

Lignin is considered by many as the ultimate barrier that impedes biomass conversion to fuels and chemicals. Several delignification strategies have been developed so far, but alkaline extraction remains the most widely used. However, this technology has a high chemical demand, consumes large amounts of water, and generates effluents that are hard to handle. Organosolv pulping is a good option for such application, but the impact of solvent losses and harmful emissions may be unsustainable. To this end, the use of greener alternatives such as water, biobased solvents, ionic liquids, and deep eutectic solvents, under sub- or supercritical conditions, may pave the road for the development of sustainable biorefineries.