Ab initio study of molecular interactions in cellulose Iα.

Biomass recalcitrance, the resistance of cellulosic biomass to degradation, is due in part to the stability of the hydrogen bond network and stacking forces between the polysaccharide chains in cellulose microfibers. The fragment molecular orbital (FMO) method at the correlated Møller-Plesset second order perturbation level of theory was used on a model of the crystalline cellulose Iα core with a total of 144 glucose units. These computations show that the intersheet chain interactions are stronger than the intrasheet chain interactions for the crystalline structure, while they are more similar to each other for a relaxed structure.

Evaluation of coarse-grained mapping schemes for polysaccharide chains in cellulose.

A fundamental understanding of the intermolecular forces that bind polysaccharide chains together in cellulose is crucial for designing efficient methods to overcome the recalcitrance of lignocellulosic biomass to hydrolysis. Because the characteristic time and length scales for the degradation of cellulose by enzymatic hydrolysis or chemical pretreatment span orders of magnitude, it is important to closely integrate the molecular models used at each scale so that, ultimately, one may switch seamlessly between quantum, atomistic, and coarse-grained descriptions of the system. As a step towards that goal, four multiscale coarse-grained models for polysaccharide chains in a cellulose-Iα microfiber are considered.