title: 3D electron tomography of pretreated biomass informs atomic modeling of cellulose microfibrils.
abstract: Fundamental insights into the macromolecular architecture of plant cell walls will elucidate new structure-property relationships and facilitate optimization of catalytic processes that produce fuels and chemicals from biomass. Here we introduce computational methodology to extract nanoscale geometry of cellulose microfibrils within thermochemically treated biomass directly from electron tomographic data sets. We quantitatively compare the cell wall nanostructure in corn stover following two leading pretreatment strategies: dilute acid with iron sulfate co-catalyst and ammonia fiber expansion (AFEX). Computational analysis of the tomographic data is used to extract mathematical descriptions for longitudinal axes of cellulose microfibrils from which we calculate their nanoscale curvature. These nanostructural measurements are used to inform the construction of atomistic models that exhibit features of cellulose within real, process-relevant biomass. By computational evaluation of these atomic models, we propose relationships between the crystal structure of cellulose Iβ and the nanoscale geometry of cellulose microfibrils.
authors.affiliation: Biosciences Center, National Renewable Energy Laboratory , 15013 Denver West Parkway, Golden, Colorado 80401, United States.
authors.forename: Peter N
authors.initials: PN
authors.lastname: Ciesielski
authors.forename: James F
authors.initials: JF
authors.lastname: Matthews
authors.forename: Melvin P
authors.initials: MP
authors.lastname: Tucker
authors.forename: Gregg T
authors.initials: GT
authors.lastname: Beckham
authors.forename: Michael F
authors.initials: MF
authors.lastname: Crowley
authors.forename: Michael E
authors.initials: ME
authors.lastname: Himmel
authors.forename: Bryon S
authors.initials: BS
authors.lastname: Donohoe
mesh_terms: D002462:Cell Membrane / Q000737:chemistry / Q000648:ultrastructure*; D003198:Computer Simulation; D055032:Electron Microscope Tomography / Q000379:methods*; D024022:Fibrillar Collagens / Q000737:chemistry / Q000648:ultrastructure*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008956:Models, Chemical; D008958:Models, Molecular; D057054:Molecular Imaging / Q000379:methods*; D011487:Protein Conformation; D003313:Zea mays / Q000737:chemistry / Q000648:ultrastructure*
chemical_list: D024022:Fibrillar Collagens