Multi-scale characterisation of deuterated cellulose composite hydrogels reveals evidence for different interaction mechanisms with arabinoxylan, mixed-linkage glucan and xyloglucan

Publication date: 25 August 2017
Source:Polymer, Volume 124
Author(s): Marta Martínez-Sanz, Deirdre Mikkelsen, Bernadine M. Flanagan, Michael J. Gidley, Elliot P. Gilbert
The interactions of cellulose with other major plant cell wall polysaccharides - arabinoxylan (AX), xyloglucan (XG) and mixed linkage glucans (MLG) - have been investigated by characterising the architecture of composite deuterated cellulose hydrogels by means of SAXS and SANS, combined with XRD, NMR and microscopy. The results indicate that cellulose-AX interactions, limited to the ribbons' surface, take place via a non-specific adsorption mechanism. In contrast, XG and MLG interact specifically with cellulose, forming two different fractions: (i) interfibrillar domains interacting with the cellulose microfibrils and (ii) surface domains, responsible for the cross-linking of ribbons. XG co-crystallises with cellulose, promoting the formation of Iβ-richer microfibrils and forming intercalated amorphous regions. On the other hand, MLG interacts with cellulose forming a paracrystalline coating layer. This structural role of XG and MLG in preventing microfibril aggregation may help explain their key function in the cell expansion process of growing plant tissues.

Graphical abstract

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