Structure of cellulose microfibrils in mature cotton fibres

Marta Martínez-Sanz; Filomena Pettolino; Bernadine Flanagan; Michael J Gidley; Elliot P Gilbert

doi:10.1016/j.carbpol.2017.07.090

Structure of cellulose microfibrils in mature cotton fibres

Carbohydr Polym. 2017 Nov 1:175:450-463. doi: 10.1016/j.carbpol.2017.07.090. Epub 2017 Aug 2.

Authors

Marta Martínez-Sanz¹, Filomena Pettolino², Bernadine Flanagan³, Michael J Gidley³, Elliot P Gilbert⁴

Affiliations

¹ Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232, Australia; ARC Centre of Excellence in Plant Cell Walls, Centre for Nutrition and Food Sciences, University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia.
² CSIRO Agriculture and Food, PO Box 1700, Canberra, ACT 2601, Australia.
³ ARC Centre of Excellence in Plant Cell Walls, Centre for Nutrition and Food Sciences, University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia.
⁴ Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232, Australia; Australian Institute for Bioengineering and Nanotechnology and Queens Land Alliance for Agriculture and Food Innovation, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia. Electronic address: elliot.gilbert@ansto.gov.au.

PMID: 28917888
DOI: 10.1016/j.carbpol.2017.07.090

Abstract

The structure of cellulose microfibrils in mature cotton fibres from three varieties - Gossypium hirsutum, G. barbadense and G. arboreum - has been investigated by a multi-technique approach combining small angle scattering techniques with spectroscopy and diffraction. Cellulose microfibrils present a Iβ-rich crystalline structure with limited surface disorder. Small angle scattering (SAXS and SANS) data have been successfully fitted using a core-shell model and the results obtained indicate that the cellulose microfibrils, formed by the association of 2-3 elementary fibrils, are composed of a ca. 2nm impermeable crystalline core, surrounded by a partially hydrated paracrystalline shell, with overall cross-sections of ca. 3.6-4.7nm. Different low levels of cell wall matrix components have a strong impact on the microfibril architecture and enable moisture penetration upon hydration. Furthermore, the higher amounts of non-cellulosic components in G. barbadense result in a less dense packing of cellulose microfibrils and increased solvent accessibility.

Keywords: Cellulose; Cotton; Neutron scattering; Plant cell walls; Small angle scattering.