Pretreatment of Wheat Straw Lignocelluloses by Deep Eutectic Solvent for Lignin Extraction

In order to increase the fractionation efficiency of the wheat straw, a deep eutectic solvent (DES) system consisting of chlorine/lactic acid was used in this study for wheat straw pretreatment. The outcomes exhibited that DES pretreatment significantly enhanced the capability to extract lignin, retain cellulose, and remove hemicellulose. The best condition for the pretreatment of wheat straw was 150 degrees C for 6 h. The process retained most cellulose in the pretreated biomass (49.94-73.60%), and the enzymatic digestibility of the pretreatment residue reached 89.98%. Further characterization of lignin showed that the high yield (81.54%) and the high purity (91.33%) resulted from the ether bond cleavage in lignin and the connection between hemicellulose and lignin. As for application, the enzymatic hydrolysis of the best condition reached 89.98%, and the lignin also had suitable stability. The investigation exhibited that DES pretreatment has the potential to realize an efficient fractionation of lignocellulosic biomass into high-applicability cellulose and lignin of high-quality.

Automated summary

In this study, a deep eutectic solvent (DES) system consisting of chlorine/lactic acid was used to pretreat wheat straw, and it was found that this pretreatment method effectively extracted lignin, retained cellulose, and removed hemicellulose. The best pretreatment condition was 150 degrees C for 6 hours, which resulted in the highest cellulose retention and an enzymatic digestibility of 89.98% for the pretreatment residue. Further characterization of lignin showed that the high yield and purity were attributed to the ether bond cleavage in lignin and the connection between hemicellulose and lignin. The study demonstrated the potential of DES pretreatment for efficient fractionation of lignocellulosic biomass into high-quality cellulose and lignin.