title: Local Phase Separation of Co-solvents Enhances Pretreatment of Biomass for Bioenergy Applications.
abstract: Pretreatment facilitates more complete deconstruction of plant biomass to enable more economic production of lignocellulosic biofuels and byproducts. Various co-solvent pretreatments have demonstrated advantages relative to aqueous-only methods by enhancing lignin removal to allow unfettered access to cellulose. However, there is a limited mechanistic understanding of the interactions between the co-solvents and cellulose that impedes further improvement of such pretreatment methods. Recently, tetrahydrofuran (THF) has been identified as a highly effective co-solvent for the pretreatment and fractionation of biomass. To elucidate the mechanism of the THF-water interactions with cellulose, we pair simulation and experimental data demonstrating that enhanced solubilization of cellulose can be achieved by the THF-water co-solvent system at equivolume mixtures and moderate temperatures (≤445 K). The simulations show that THF and water spontaneously phase separate on the local surface of a cellulose fiber, owing to hydrogen bonding of water molecules with the hydrophilic cellulose faces and stacking of THF molecules on the hydrophobic faces. Furthermore, a single fully solvated cellulose chain is shown to be preferentially bound by water molecules in the THF-water mixture. In light of these findings, co-solvent reactions were performed on microcrystalline cellulose and maple wood to show that THF significantly enhanced cellulose deconstruction and lignocellulose solubilization at simulation conditions, enabling a highly versatile and efficient biomass pretreatment and fractionation method.
authors.affiliation: UT/ORNL Center for Molecular Biophysics, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37830, United States.|Joint Institute for Biological Sciences, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37830, United States.|BioEnergy Science Center, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37830, United States.
authors.forename: Barmak
authors.initials: B
authors.lastname: Mostofian
authors.affiliation: BioEnergy Science Center, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37830, United States.|Center for Environmental Research and Technology (CE-CERT), Bourns College of Engineering, University of California , Riverside, California 92507, United States.|Department of Chemical and Environmental Engineering, Bourns College of Engineering, University of California , Riverside, California 92521, United States.
authors.forename: Charles M
authors.initials: CM
authors.lastname: Cai
authors.affiliation: UT/ORNL Center for Molecular Biophysics, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37830, United States.|BioEnergy Science Center, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37830, United States.|Department of Biochemistry, Cellular & Molecular Biology, The University of Tennessee , Knoxville, Tennessee 37996, United States.
authors.forename: Micholas Dean
authors.initials: MD
authors.lastname: Smith
authors.affiliation: UT/ORNL Center for Molecular Biophysics, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37830, United States.|BioEnergy Science Center, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37830, United States.|Department of Biochemistry, Cellular & Molecular Biology, The University of Tennessee , Knoxville, Tennessee 37996, United States.
authors.forename: Loukas
authors.initials: L
authors.lastname: Petridis
authors.affiliation: UT/ORNL Center for Molecular Biophysics, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37830, United States.|BioEnergy Science Center, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37830, United States.|Department of Biochemistry, Cellular & Molecular Biology, The University of Tennessee , Knoxville, Tennessee 37996, United States.
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Cheng
authors.affiliation: BioEnergy Science Center, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37830, United States.|Center for Environmental Research and Technology (CE-CERT), Bourns College of Engineering, University of California , Riverside, California 92507, United States.|Department of Chemical and Environmental Engineering, Bourns College of Engineering, University of California , Riverside, California 92521, United States.
authors.forename: Charles E
authors.initials: CE
authors.lastname: Wyman
authors.affiliation: UT/ORNL Center for Molecular Biophysics, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37830, United States.|BioEnergy Science Center, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37830, United States.|Department of Biochemistry, Cellular & Molecular Biology, The University of Tennessee , Knoxville, Tennessee 37996, United States.
authors.forename: Jeremy C
authors.initials: JC
authors.lastname: Smith
mesh_terms: D018533:Biomass; D002236:Carbohydrate Conformation; D002482:Cellulose / Q000737:chemistry*; D005663:Furans / Q000737:chemistry; D008958:Models, Molecular; D012995:Solubility; D012997:Solvents / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D005663:Furans; D012997:Solvents; D014867:Water; C018674:tetrahydrofuran; D002482:Cellulose