Lignin Removal in Subcellular Location of Poplar Cell Wall During Pretreatment Significantly Impacts Cellulose Digestibility
Year: 2025
Type: article
Abstract: The γ-valerolactone (GVL) pretreatment is one of the leading solvent-based methods for producing high-quality lignin under mild conditions. However, the glucan conversion yield from GVL pretreated biomass remains unsatisfactory. To explore the discrepancies between the relatively low glucan conversion and high lignin extraction, we conducted GVL-HCl and NaOH pretreatments on poplar and investigated their effects on lignin content and location, as well as on enzymatic hydrolysis of poplar cell walls at the subcellular level. Under designated pretreatment conditions of GVL-HCl (90% GVL, 0.1 M HCl, 100 °C, 1 h) and NaOH (1 M, 121 °C, 2 h), the glucan conversion yields were 69.4% and 95.8%, with lignin removal rates of 67.8% and 47.7%, respectively. Four types of GFP-labeled carbohydrate binding modules were used to identify different forms of cellulose in the pretreated cell walls. The overall binding intensities to pretreated poplar were stronger for NaOH compared to GVL-HCl pretreatment. Stimulated Raman scattering microscopy imaging revealed that GVL-HCl preferentially extracted lignin from the compound middle lamella and cell corner areas, while NaOH effectively dissolved lignin in the secondary cell walls. Real-time imaging of cellulase degradation of pretreated cell walls further indicated that digestion started from both the cell lumen and the compound middle lamella areas for GVL, whereas it occurred uniformly across the secondary cell walls for NaOH. Our findings suggest that the location of lignin removal during pretreatment is crucial for enzymatic cellulose degradation, in addition to the total amount of lignin extraction.
Language: English
Subfield: Biomedical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,500
Funders: National Science Foundation, U.S. Department of Energy, University of Wisconsin-Madison, Michigan State University, Natural Science Foundation of Xiamen City, National Natural Science Foundation of China, Chinese Academy of Sciences, Haixi Institute, Chinese Academy of Sciences, East China University of Science and Technology, Office of Science, College of Engineering, Michigan State University, Great Lakes Bioenergy Research Center, Fujian Institute of Research on the Structure of Matter, Biological and Environmental Research
Awards: G1648283888, G1718088338, G2301390204, Radionuclide Immobilization in Reducing Cementitious Materials, MCA: Understanding cellulose synthase complex in planta using single molecule methods, G3444752832, GREAT LAKES BIOENERGY RESEARCH CENTER, G455569901, G5535031243, REAL-TIME IMAGING AND QUANTIFICATION OF PLANT CELL WALL CONSTITUENTS USING CAVITY-DUMPED STIMULATED RAMAN SCATTERING (CDSRS) MICROSCOPY, G7350903426, G8732373744, GREAT LAKES BIOENERGY RESEARCH CENTER, G8794194214
OpenAlex ID: W4410518651