Monitoring and Analyzing Process Streams Towards Understanding Ionic Liquid Pretreatment of Switchgrass (Panicum virgatum L.)

• Published in: Bioenergy research 2010-06, Vol.3 (2), p.134-145
• Main Authors: Arora, Rohit, Manisseri, Chithra, Li, Chenlin, Ong, Markus D, Scheller, Henrik Vibe, Vogel, Kenneth, Simmons, Blake A, Singh, Seema
• Format: Article
• Language: English
• Subjects: 1-ethyl-3-methyl imidazolium acetate; Acetates; Acids; Agricultural production; Alternative energy sources; Biodiesel fuels; Biofuels; Biomass; Biomass energy; Biomedical and Life Sciences; Carbon; Cellulase; Cellulase kinetics; cellulases; Cellulose; chemical treatment; delignification; duration; Energy minerals; Enzyme kinetics; Enzymes; Ethanol; Fossil fuels; glucans; Glucose; Grasses; Ionic liquid; Ions; Kinetics; Laboratories; Life Sciences; Lignin; Lignocellulose; Monosaccharides; Panicum virgatum; Plant Breeding/Biotechnology; Plant Ecology; Plant Genetics and Genomics; Plant Sciences; Porosity; pretreatment; Saccharides; saccharification; Studies; Sugar; Sugars; Surface area; temperature; Transition temperatures; Wood Science & Technology; xylan; yields
• ISSN: 1939-1234; 1939-1242
• DOI: 10.1007/s12155-010-9087-1

Fundamental understanding of biomass pretreatment and its influence on saccharification kinetics, total sugar yield, and inhibitor formation is essential to develop efficient next-generation biofuel strategies, capable of displacing fossil fuels at a commercial level. In this study, we investigated the effect of residence time and temperature during ionic liquid (IL) pretreatment of switchgrass using 1-ethyl-3-methyl imidazolium acetate. The primary metrics of pretreatment performance are biomass delignification, xylan and glucan depolymerization, porosity, surface area, cellulase kinetics, and sugar yields. Compositional analysis and quantification of process streams of saccharides and lignin demonstrate that delignification increases as a function of pretreatment temperature and is hypothesized to be correlated with the apparent glass transition temperature of lignin. IL pretreatment did not generate monosaccharides from hemicellulose. Compared to untreated switchgrass, Brunauer-Emmett-Teller surface area of pretreated switchgrass increased by a factor of ∼30, with a corresponding increase in saccharification kinetics of a factor of ∼40. There is an observed dependence of cellulase kinetics with delignification efficiency. Although complete biomass dissolution is observed after 3 h of IL pretreatment, the pattern of sugar release, saccharification kinetics, and total sugar yields are strongly correlated with temperature.