The adsorption of xyloglucan and pectin to model crystalline and amorphous cellulose substrates

The plant cell wall is the major source of cellulose, which is considered as a raw material for next generation biofuels. An understanding of cell wall polymers interactions would benefit the pretreatment process for producing biofuel. In this study, two typical cell wall polysaccharides, xyloglucan and pectin were used to study their adsorption to non-chemically modified cellulose. Two cellulose substrates were prepared and characterized including highly crystalline cellulose nanowhiskers (CNWs) from cotton and amorphous cellulose derived from CNWs (phosphoric acid swollen cellulose nanowhiskers, PASCNWs). Different concentrations of xyloglucan and pectin solutions were mixed with the model cellulose substrates. The amount of binding and the binding constant of xyloglucan and pectin to cellulose were obtained with adsorption isotherm. Langmuir function was used to fit the data. The affinity of xyloglucan to any cellulose substrate was higher than that of pectin. This study indicates that the adsorption of xyloglucan and pectin on cellulose depends on the crystallinity and surface area of the cellulose substrates as well as the ionic strength of the system.