CELLULOSE-LIGNIN INTERACTIONS - A COMPUTATIONAL STUDY

Within a broader program of study of the molecular structure of plant cell walls, molecular dynamics calculations were used to explore the c haracter of the motion of lignin model compounds near a cellulose surf ace. Model cellulose microfibrils, which have a large number of hydrox yl groups on the surface, appear to have a net attractive interaction with the lignin models examined in this study. The lignin monomer coni feryl alcohol rapidly adsorbed onto the surface from a water layer aft er it was released 13 Angstrom from the surface. The major long-range force responsible for this adsorption is likely electrostatic, The att ractive interaction is sufficient to restrict the motion of coniferyl alcohol when it is within 1 Angstrom of the surface and to orient the phenyl ring parallel to the surface. The beta-O-4-linked trimer also w as observed to adsorb onto the surface with two of its phenyl rings pa rallel to the surface, These results suggest a mechanism by which the polysaccharide component of the plant cell wall could influence the st ructure of lignin. Furthermore, they provide a rationalization of the experimental observation that polysaccharides can change the course of dehydrogenation polymerization of cinnamyl alcohols.