Evaluation of pretreatment effect on lignin extraction from wheat straw by deep eutectic solvent. (January 2022)

• Record Type: Journal Article
• Authors: Lou, Rui; Zhang, Xiao
• Is Part Of: Bioresource technology. Volume 344:Part B(2022)
• Publication Date: 2022-01
• Subjects: Wheat straw -- Lignin -- Deep eutectic solvents (DES) -- Presoaking -- Hydrogen bonding; Biomass -- Periodicals; Biomass energy -- Periodicals; Bioremediation -- Periodicals; Agricultural wastes -- Periodicals; Factory and trade waste -- Periodicals; Organic wastes -- Periodicals; Bioénergie -- Périodiques; Déchets agricoles -- Périodiques; Déchets industriels -- Périodiques; Déchets organiques -- Périodiques; Déchets (Combustible) -- Périodiques; 662.88
• DOI: 10.1016/j.biortech.2021.126174
• Languages: English
• ISSNs: 0960-8524

Abstract

Graphical abstract: This study investigates the extraction of lignin from wheat straw biomass using deep eutectic solvent (DES) combining with presoaking treatments using both ChCl-LA based DES and hot water. This study has revealed that hemicellulose removal does not always improve lignin extraction by DES from wheat straw. Fiber cell wall morphological and structural changes resulted from the hemicellulose removal have a more direct impact on subsequent lignin extraction. A two-stage DES treatment method, presoaking at room temperature followed by extraction at an elevated temperature, is a viable process to produce high yield and purity of lignin. Highlights: Presoakings can hydrolyze hemicellulose but do not always improve lignin extraction. Morphological and structural changes have a more direct impact on lignin extraction. Providing new insights toward dissolution mechanism of lignin in DES-biomass system. A two-stage DES treatment method seems viably to produce high-yield lignin. Abstract: To investigate the effect of hemicellulose removal on subsequent choline chloride and lactic acid (ChCl-LA) based deep eutectic solvent (DES) extraction of wheat straw lignin, ChCL-LA of DES and hot water presoaking pretreatments were used for hemicellulose prehydrolysis. Both presoakings led to a significant hemicellulose removal and introduced morphological changes on fiber cell wall surface. DES presoaking also instigated ether bonds cleavage between lignin and hemicellulose and selectively removed lignin in compound middle lamella (CML) and cell corner (CC) leading to cell wall disruption and swelling which facilitated lignin extraction. Hot water presoaking removed more hemicellulose and caused a migration of lignin to fibers surface, but did not improve subsequent lignin extraction. This study demonstrated that a two-stage DES treatment method, presoaking at room temperature followed by extracting at an elevated temperature, is a viable process to produce high yield and purity of lignin.