Bacterial cellulose (BC) gels produced by Acetobacter xylinum were used as model substrates for studying xylan assembly. The assembly of xylan onto BC surfaces was carried out by exposing BC films to xylan solutions under autoclave treatments. The BC surfaces were found to retain significantly higher amounts of xylan than cellulose fibers from cotton or dissolving pulp under the same conditions. The morphology of BC/xylan surfaces was visualized using atomic force microscopy. Globular xylan particles in the nanometer scale were found on the cellulose surfaces even after short treatment times, suggesting that the surface structures are formed by adsorption of preformed xylan aggregates from the solution rather than being built up at the cellulose surfaces with time by multilayer adsorption of xylan. Dynamic light scattering measurements of solutions support this hypothesis by revealing increases in both size and amount of xylan aggregates with increased treatment time. The increased aggregation can be explained by the decreased amounts of solubilizing 4-O-methyl glucuronic acid substituents in the autoclaved xylans, as shown by carbohydrate analysis. The retention of xylans on cellulose surfaces under conditions similar to those in wood pulping is likely to take place through an adsorption process involving diffusion to, and subsequent interaction with, cellulose surfaces of preformed xylan aggregate structures.
Summary In this study we have shown that cellulose fibres can be coated with regular micron-sized particles by controlling the assembly process of xylans on the cellulose surfac...
Production of cellulose has been thought to be restricted to a few bacterial species such as the model organism Acetobacter xylinus . We show by enzymatic analysis and mass spec...
Molecular self-assembly is the spontaneous association of molecules under equilibrium conditions into stable, structurally well-defined aggregates joined by noncovalent bonds. M...
Surface morphology changes of hydrazine-RF-plasma-exposed cellophane surfaces were monitored under 40 kHz and 13.56 MHz CW and pulsed discharge environments and the immobilizati...
The arginine-rich fraction of calf thymus histone (histone B) exerts bactericidal activity on various coliform bacilli and micrococci under certain conditions in vitro. Final co...
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