Pretreatment with ChOH/Urea under mild conditions for the efficient deconstruction of poplar cell wall

Abstract

In this study, DES consisting of Choline hydroxide (ChOH) and Urea (Ur) was used to pretreat poplar under mild conditions (60 ℃). The 72 h saccharification efficiency of the pretreated samples for 10 min was significantly improved (69.97 %), which amounted to a 2.4-fold increase in sugar yield over the raw material (29.89 %). The remarkable enhancement could be correlated to the topochemical and morphological changes occurring in poplar cell walls, including the removal of lignin and hemicelluloses, decreased crystallinity and microstructural disruption. Noteworthy, X-ray diffraction analysis showed that cellulose I underwent a crystallographic transformation from cellulose I to cellulose II during DES pretreatment. Our study demonstrated that ChOH/Ur pretreatment was quite effective in deconstructing poplar cell walls and increasing the enzymatic hydrolysis efficiency of cellulose under mild conditions.