Structural differences of xylans affect their interaction with cellulose

The affinity of xylan to cellulose is an important aspect of many industrial processes, e.g. production of cellulose, paper making and bio-ethanol production. However, little is known about the adsorption of structurally different xylans to cellulose. Therefore, the adsorption of various xylans to bacterial cellulose (BC) was studied. Also, the relationship between xylan size and adsorption was analysed. BC was used as cellulosic material, because of its high specific surface area and homogeneous structure. In general, unsubstituted linear xylan parts favoured adsorption to BC. Xylan affinity for BC was also related to xylan size. The presence of arabinosyl and O-acetyl substituents to xylan decreased the adsorption of xylan to BC considerably. Removing substituents resulted in higher amounts of adsorbed material. Most likely, increasing the number of unsubstituted xylosyl residues induced the formation of xylan-xylan interactions, which contributed to adsorption to BC. Schematic models are proposed showing the adsorption of structurally different xylans to BC. (c) 2006 Elsevier Ltd. All rights reserved.