Abstract
Several deep eutectic solvents (DESs) have been demonstrated to be highly effective for lignocellulosic biomass pretreatment, combining the advantages of simple synthesis, relatively low chemical cost and better biocompatibility. However, low biomass loading that is usually involved with DES pretreatment hinders its practical use. In this study, a twin-screw extruder was used for pretreating biomass sorghum bagasse at solid loadings up to 50%, mediated by a neutral-pH DES, choline chloride : glycerol (ChCl : Gly). This continuous extrusion process led to high glucose and xylose yields of >85% from enzymatic saccharification of the pretreated sorghum. A combination of microscopic, spectroscopic, and X-ray diffraction analyses demonstrate a high degree of defibration and disruption of the biomass cell wall structures; however, little or no change in chemical compositions. Further results from gel permeation chromatographic (GPC) and nuclear magnetic resonance (NMR) spectroscopic analyses indicate that ChCl : Gly-mediated extrusion preserved the basic lignin structural characteristics with no significant differences between extruded biomass at a solid loading of 30% and 50%. This study demonstrates the potential of DES-mediated extrusion as a highly effective continuous high-solid biomass pretreatment technology for industrially relevant applications.
| Original language | English |
|---|---|
| Pages (from-to) | 6372-6383 |
| Number of pages | 12 |
| Journal | Green Chemistry |
| Volume | 22 |
| Issue number | 19 |
| DOIs | |
| State | Published - Oct 7 2020 |
Funding
The authors at University of Kentucky acknowledge the National Institute of Food and Agriculture, U.S. Department of Agriculture, Sustainability Challenge Area grant under accession number 1015068 and Hatch-Multistate project under accession number 1018315. This work was also supported by the National Natural Science Foundation of China (No. 51708548), China Scholarship Council (No. 201803260012), and Central Public-interest Scientific Institution Basal Research Fund for Chinese Academy of Tropical Agricultural Sciences (No. 17CXTD-05). Oak Ridge National Laboratory is managed by UT-Battelle, LLC, under Contract DE-AC05-00OR22725 with the U.S. Department of Energy (DOE). Y.P. and A.J.R acknowledge the support from the Center for Bioenergy Innovation (CBI), a U.S. DOE Bioenergy Research Center supported by the Office of Biological and Environmental Research in the DOE Office of Science. The views and opinions of the authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed or represents that its use would not infringe privately owned rights. We thank Novozymes for providing enzyme samples and the Idaho National Laboratory for providing biomass materials.