title: Conformations of Low-Molecular-Weight Lignin Polymers in Water.
abstract: Low-molecular-weight lignin binds to cellulose during the thermochemical pretreatment of biomass for biofuel production, which prevents the efficient hydrolysis of the cellulose to sugars. The binding properties of lignin are influenced strongly by the conformations it adopts. Here, we use molecular dynamics simulations in aqueous solution to investigate the dependence of the shape of lignin polymers on chain length and temperature. Lignin is found to adopt collapsed conformations in water at 300 and 500 K. However, at 300 K, a discontinuous transition is found in the shape of the polymer as a function of the chain length. Below a critical degree of polymerization, Nc =15, the polymer adopts less spherical conformations than above Nc. The transition disappears at high temperatures (500 K) at which only spherical shapes are adopted. An implication relevant to cellulosic biofuel production is that lignin will self-aggregate even at high pretreatment temperatures.
authors.affiliation: Center for Molecular Biophysics, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA. petridisl@ornl.go.
authors.forename: Loukas
authors.initials: L
authors.lastname: Petridis
authors.affiliation: Center for Molecular Biophysics, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.|Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, 37996, USA.
authors.forename: Jeremy C
authors.initials: JC
authors.lastname: Smith
mesh_terms: D056804:Biofuels; D018533:Biomass; D002236:Carbohydrate Conformation; D057927:Hydrophobic and Hydrophilic Interactions; D008031:Lignin / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D008970:Molecular Weight; D013696:Temperature; D014867:Water / Q000737:chemistry*
chemical_list: D056804:Biofuels; D014867:Water; D008031:Lignin
keywords: aggregation; biomass; conformation analysis; molecular dynamics; polyamphiphiles