title: Towards a deeper understanding of structural biomass recalcitrance using phase-contrast tomography.
abstract: BACKGROUND
  The development of technological routes to convert lignocellulosic biomass to liquid fuels requires an in-depth understanding of the cell wall architecture of substrates. Essential pretreatment processes are conducted to reduce biomass recalcitrance and usually increase the reactive surface area. Quantitative three-dimensional information about both bulk and surface structural features of substrates needs to be obtained to expand our knowledge of substrates. In this work, phase-contrast tomography (PCT) was used to gather information about the structure of a model lignocellulosic biomass (piassava fibers).
  
  
  RESULTS
  The three-dimensional cellular organization of piassava fibers was characterized by PCT using synchrotron radiation. This technique enabled important physical features that describe the substrate piassava fibers to be visualized and quantified. The external surface area of a fiber and internal surface area of the pores in a fiber could be determined separately. More than 96% of the overall surface area available to enzymes was in the bulk substrate. The pore surface area and length exhibited a positive linear relationship, where the slope of this relationship depended on the plant tissue.
  
  
  CONCLUSIONS
  We demonstrated that PCT is a powerful tool for the three-dimensional characterization of the cell wall features related to biomass recalcitrance. Original and relevant quantitative information about the structural features of the analyzed material were obtained. The data obtained by PCT can be used to improve processing routes to efficiently convert biomass feedstock into sugars.
authors: Department of Metallurgical and Materials Engineering, Universidade Federal de Minas Gerais - UFMG, Avenida Presidente Antônio Carlos, 6627, 31270-901 Belo Horizonte, MG Brazil.
authors: Augusta
authors: A
authors: Isaac
authors: Institute of Computing, Universidade Estadual de Campinas - UNICAMP, Avenida Albert Einstein, Cidade Universitária Zeferino Vaz - Barão Geraldo, 13081-970 Campinas, SP Brazil.
authors: Vinicius
authors: V
authors: Barboza
authors: Instituto Madrileño de Estudios Avanzados - IMDEA, E.T.S. de Ingeniería de Caminos C/ Profesor Aranguren, 28040 Madrid, Spain.
authors: Federico Ivan
authors: FI
authors: Sket
authors: Materials Engineering Department, Pontifícia Universidade Católica do Rio de Janeiro, Rua Marques de São Vicente, 225, Gávea, 22451-900 Rio de Janeiro, RJ Brazil.
authors: José Roberto M
authors: JR
authors: D'Almeida
authors: Department of Chemistry, Universidade Federal de Minas Gerais - UFMG, Avenida Presidente Antônio Carlos, 6627, 31270-901 Belo Horizonte, MG Brazil.
authors: Luciano Andrey
authors: LA
authors: Montoro
authors: Institute of Applied Materials, Helmholtz-Zentrum Berlin, Hahn-Meitner-Platz 1, 14109 Berlin, Germany.
authors: André
authors: A
authors: Hilger
authors: Institute of Applied Materials, Helmholtz-Zentrum Berlin, Hahn-Meitner-Platz 1, 14109 Berlin, Germany.
authors: Ingo
authors: I
authors: Manke
keywords: Biomass; Phase-contrast tomography; Recalcitrance; Surface area; Synchrotron radiation