Green fractionation approaches for isolation of biopolymers and the critical technical challenges

In analogue to the biorefinery concept, the separation process of lignocellulosic biomass is the most critical step to obtain its main components, namely cellulose, hemicelluloses and lignin. Moreover, the applied fractionation approach has a decisive impact on the characteristics and subsequent valorization strategies of the distinguished fractions. This review presents the state of art of novel biomass fractionation processes that are recently developed and focusing on autohydrolysis, organosolv fractionation, ionic liquid and deep eutectic solvent (DES) treatment. Moreover, the facing challenges, perspectives and future development direction in the field of fractionation of lignocellulosic biomass are discussed. The purpose of this review is to provide inspiration and guidance for fractionating biomass with environmentally friendly and efficient pathways, thus to push forward their further industrialization based on the integrated biorefinery concept.