Abstract
Novel and sustainable pretreatment approaches are desired to improve the techno-commercial feasibility of biorefineries in the future. In this study, 10 renewable deep eutectic solvents (DESs) were evaluated for their pretreatment efficiency at facile conditions with sugar cane bagasse as substrate and compared with conventional pretreatment approaches (dilute alkali, dilute acid, and ionic liquid (IL)) for lignin removal, saccharification yield, cellulose accessibility, crystallinity, and physiochemical properties. Although, the highest delignification was obtained with dilute alkali (59.7%) and choline chloride:lactic acid or ChCl:LA (50.6%), the maximum enzymatic conversion of 98.0% and 90.4% was observed with IL (1-butyl-3-methylimidazolium acetate) and ChCl:LA, respectively. uclear magnetic resonance analysis of ChCl:LA-derived lignin showed selective removal of guaiacyl lignin without condensation structure formation observed. Interestingly, unlike IL, the lignin was substantially depolymerized after ChCl:LA pretreatment as determined by gel permeation chromatography. Further, high compatibility of ChCl:LA with cellulase in comparison of IL with easy recyclability and recycling showed that DESs synthesized from a renewable resource are promising "green" solvents for future biorefinery operations.
| Original language | English |
|---|---|
| Pages (from-to) | 1095-1104 |
| Number of pages | 10 |
| Journal | ACS Sustainable Chemistry and Engineering |
| Volume | 7 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jan 7 2019 |
Funding
The first Bioenergy Award for Cutting Edge Research (BACER) conferred to Dr. Alok Satlewal from the Department of Biotechnology, Ministry of Science and Technology, Government of India and Indo-US Science and the Technology Forum is duly acknowledged. All of the financial and administrative support by Indian Oil R&D Centre, Sector 13, Faridabad is gratefully acknowledged. Oak Ridge National Laboratory is managed by UT-Battelle, LLC under Contract DE-AC05-00OR22725 with the U.S. Department of Enegy (DOE). We are grateful to the Advanced Microscopy and Imaging Center and Joint Institute of Advanced Materials (JIAM) at the University of Tennessee, Knoxville, TN, for providing instruments and facilities for SEM imaging. We also thank Mr. Seth A. Anderson, an undergraduate student, CBE, UTK, for providing assistance during this study.
Keywords
- deep eutectic solvents
- ionic liquid
- lignin
- pretreatment
- sugar cane bagasse