Simultaneous influence of pectin and xyloglucan on structure and mechanical properties of bacterial cellulose composites

Abstract

The impact of the matrix polysaccharides on the cellulose microfibrils structure as well as on the mechanical properties of cell walls still remains an open question. Therefore, the aim of investigations was to determine the simultaneous influence of (i) different concentrations of pectins with constant concentration of xyloglucan, and (ii) different concentrations of xyloglucan with constant concentration of pectins on cellulose structure. Composites of bacterial cellulose (BC) produced by Komagataeibacter xylinus are considered to mimic natural plant cell walls. This investigation showed that the lower the ratio of xyloglucan to pectin was, the higher Young's modulus of BC composite was and also obtained cellulose microfibrils were thinner. The increasing concentration of xyloglucan to pectin also caused the drop down in microfibrils crystallinity degree with predominant structure of cellulose I_β. In that case, also the length of cellulose chains was growing and reaching the highest value among all BC composites.

Keywords: AFM; Bacterial cellulose; Cellulose crystallinity; Mechanical properties; Pectins; Xyloglucan.