Green and efficient alkaline DES pretreatment for full-component fractionation of reed biomass: Hemicelluloses, uncondensed lignin and easily digestible cellulose

Efficient fractionation of reed biomass and tailored downstream high value-added applications are crucial for biorefining sustainability. To address the issues of hemicelluloses non-recovery and lignin structure destruction during DES pretreatment, a green and efficient alkaline deep eutectic solvent (ADES) pretreatment strategy was developed. The strategy aims to achieve efficient fractionation of reed biomass, while providing uncondensed lignin, hemicelluloses with high structural retention, and easily digestible cellulose residues for bioenergy and chemicals. Results demonstrated that the proposed ADES pretreatment strategy exhibited excellent capability in deconstructing biomass component, achieving a delignification efficiency of 82.95 wt%-96.13 wt% (ADES-NAP/CAP/CEM systems at 120–160 °C for 10 min). Meanwhile, lignin fractions had excellent antioxidant activity and well-preserved structure (high content of β- O -4 aryl ether bonds), which facilitated to the development of downstream applications and monomer production (29.34 wt%-41.16 wt% via reductive catalytic degradation at 180–260 °C). On the other hand, the pretreatment efficiently removed hemicelluloses (83.49 wt%-97.61 wt%), while enabling the recovery of high-purity hemicelluloses with structural integrity well-preserved. The ADES cellulose residues achieved 60.39 wt%-97.68 wt% fermentable glucose yield at low enzyme loading (10 FPU/g) during enzymatic saccharification, with a total biorefinery yield exceeding 81 %. In summary, the proposed ADES pretreatment strategy not only solved the problem of hemicelluloses degradation during DES pretreatment but also realized efficient separation, conversion and utilization of all components within reed biomass.