  Inorganic salts are a natural component of biomass which have a significant
effect on the product yields from a variety of biomass conversion processes.
Understanding their effect on biomass at the microscopic level can help
discover their mechanistic role. We present a study of the effect of aqueous
sodium chloride (NaCl) on the largest component of biomass, cellulose, focused
on the thermodynamic and structural effect of a sodium ion on the cellulose
tetramer, and fibril. Replica exchange molecular dynamics simulations of a
cellulose tetramer reveal a number of preferred cellulose-Na contacts and
bridging positions. Large scale MD simulations on a model cellulose fibril find
that Na+ perturbs the hydroxymethyl rotational state population and
consequently disrupts the "native" hydrogen bonding network.
