Journal of Energy Bioscience 2024, Vol.15, No.1, 28-31 http://bioscipublisher.com/index.php/jeb 30 Figure 4 Atomistic model of the lignocellulose assembly within the Populus SCW that best represents ssNMR observables Note: (A) Molecular representation of the individual biopolymer constituents. (B) Macromolecular assembly of cellulose, xylan, and lignin. the xylan domains on the surface of cellulose adopt an extended confguration with decorations pointing away from the cellulose surface toward lignin. (C) visualization of the cellulosic components only, showing two core bundles comprising four 18-chain elementary fbrils. (D) visualization of the hemicellulose components only shows the nearly complete sheath formed around the cellulose minimizing direct contact between cellulose and lignin; also, some xylan is found between core bundles, isolated from lignin. (E) lignin interacts predominantly with hemicellulose and displays minimal direct contact with cellulose Figure 5 contrasts the conformations of xylan polymers based on their proximity to cellulose. Panel A shows that xylan bound to cellulose adopts conformations with acetate groups consistently oriented away from the surface, while unbound xylan displays random acetate group orientations. Panel B highlights the broad distribution of φ + ψ dihedral angles in unbound xylan, peaking around 170°. Panel C indicates that bound xylan, despite a wide φ + ψ distribution, prominently peaks at approximately 100°. Panel D demonstrates a wide θ2f (O2-C5-C5-O2) dihedral angle distribution for unbound xylan, reflecting nonuniform acetate orientations. Conversely, Panel E shows a narrow θ2f distribution centered at 0° for bound xylan, signifying consistent acetate orientations. Panels F and G define these dihedral measurements, emphasizing structural differences driven by cellulose binding. 2 Insight of Research Findings The study shows that the SCW's mechanical integrity and resistance to deconstruction arise from the complex interactions between cellulose, hemicelluloses, and lignin. The ssNMR data reveal subnanometer interactions, essential for understanding the SCW's structure. Molecular dynamics simulations support these findings, confirming the significance of initial polymer placement and suggesting minimal rearrangement over time. 3 Evaluation of the Research The research successfully integrates ssNMR data with molecular dynamics simulations to provide a detailed macromolecular model of the SCW. The study's approach offers valuable insights into the structural arrangement of biopolymers, contributing to a better understanding of lignocellulosic biomass and its potential applications. However, limitations include the reliance on spectral deconvolution and the need for further investigation into different cell types and more mature wood samples. 4 Concluding Remarks The study advances our understanding of the SCW architecture in Populus wood, highlighting the importance of polymer interactions at the nanometer scale. The integration of experimental and computational methods provides a robust framework for future research on plant cell wall structures and their applications in renewable energy and materials science.
RkJQdWJsaXNoZXIy MjQ4ODYzMg==