title: Diffraction evidence for the structure of cellulose microfibrils in bamboo, a model for grass and cereal celluloses.
abstract: BACKGROUND
  Cellulose from grasses and cereals makes up much of the potential raw material for biofuel production. It is not clear if cellulose microfibrils from grasses and cereals differ in structure from those of other plants. The structures of the highly oriented cellulose microfibrils in the cell walls of the internodes of the bamboo Pseudosasa amabilis are reported. Strong orientation facilitated the use of a range of scattering techniques.
  
  
  RESULTS
  Small-angle neutron scattering provided evidence of extensive aggregation by hydrogen bonding through the hydrophilic edges of the sheets of chains. The microfibrils had a mean centre-to-centre distance of 3.0 nm in the dry state, expanding on hydration. The expansion on hydration suggests that this distance between centres was through the hydrophilic faces of adjacent microfibrils. However in the other direction, perpendicular to the sheets of chains, the mean, disorder-corrected Scherrer dimension from wide-angle X-ray scattering was 3.8 nm. It is possible that this dimension is increased by twinning (crystallographic coalescence) of thinner microfibrils over part of their length, through the hydrophobic faces. The wide-angle scattering data also showed that the microfibrils had a relatively large intersheet d-spacing and small monoclinic angle, features normally considered characteristic of primary-wall cellulose.
  
  
  CONCLUSIONS
  Bamboo microfibrils have features found in both primary-wall and secondary-wall cellulose, but are crystallographically coalescent to a greater extent than is common in celluloses from other plants. The extensive aggregation and local coalescence of the microfibrils are likely to have parallels in other grass and cereal species and to influence the accessibility of cellulose to degradative enzymes during conversion to liquid biofuels.
authors.affiliation: Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK. l.h.thomas@bath.ac.uk.
authors.forename: Lynne H
authors.initials: LH
authors.lastname: Thomas
authors.affiliation: Institut Laue-Langevin, Grenoble, Cedex 9 38042, France. tforsyth@ill.fr.|EPSAM/ISTM, Keele University, Staffordshire, ST5 5BG, UK. tforsyth@ill.fr.
authors.forename: V Trevor
authors.initials: VT
authors.lastname: Forsyth
authors.affiliation: Institut Laue-Langevin, Grenoble, Cedex 9 38042, France. martela@ill.fr.
authors.forename: Anne
authors.initials: A
authors.lastname: Martel
authors.affiliation: Institut Laue-Langevin, Grenoble, Cedex 9 38042, France. grillo@ill.eu.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Grillo
authors.affiliation: New Zealand School of Forestry, University of Canterbury, Christchurch, 4180, New Zealand. clemens.altaner@canterbury.ac.nz.
authors.forename: Clemens M
authors.initials: CM
authors.lastname: Altaner
authors.affiliation: School of Chemistry, Glasgow University, Glasgow, G12 8QQ, UK. michael.jarvis@glasgow.ac.uk.
authors.forename: Michael C
authors.initials: MC
authors.lastname: Jarvis
mesh_terms: D002473:Cell Wall / Q000737:chemistry; D002482:Cellulose / Q000737:chemistry*; D020894:Microfibrils / Q000737:chemistry*; D006109:Poaceae / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D002482:Cellulose