(576c) Mesoscale Modeling of Plant Cell Walls and Understanding Their Mechanics during Cell Growth

Cell walls, which consist mainly of cellulose microfibrils and amorphous polysaccharides, are the major source of biomass for the production of biofuels. The efficient conversion of cell wall materials to biofuels requires a fundamental understanding of the cell wall structure and its mechanics. The complex nature of the wall due to the hierarchical assembly of cellulose fibrils and their interactions with polysaccharides demands a synergistic approach involving computational modeling and experimental studies. In this work, we adopt a mesoscale modeling approach and develop a generalized coarse-grained (CG) model of cell wall consisting of three key components – cellulose microfibrils, hemicellulose, and pectins. Each component in the model is represented as beads connected by harmonic springs and the interaction parameters are obtained by systematic optimization based on experimental data. As the model consists of interpretable parameters, it can be easily modified to account for additional heterogeneity in the system. Using this model and employing Dissipative Particle Dynamics (DPD) simulation technique, we will elucidate the role of cell wall components on the mechanical response of the cell wall during deformation. In particular, results correlating the stiffness of the wall components with the elastic and plastic response of the cell wall will be discussed. Finally, a comparison between the experimentally observed response of cellulose fibrils and those predicted from the CG model during deformation will be highlighted.