Skip to main content

Morphological changes in the cellulose and lignin components of biomass occur at different stages during steam pretreatment


Morphological changes to the different components of lignocellulosic biomass were observed as they occurred during steam pretreatment by placing a pressure reaction cell in a neutron beam and collecting time-resolved neutron scattering data. Changes to cellulose morphology occurred mainly in the heating phase, whereas changes in lignin morphology occurred mainly in the holding and cooling phases. During the heating stage, water is irreversibly expelled from cellulose microfibrils as the elementary fibrils coalesce. During the holding phase lignin aggregates begin to appear and they increase in size most noticeably during the cooling phase. This experiment demonstrates the unique information that in situ small angle neutron scattering studies of pretreatment can provide. This approach could be useful in optimizing the heating, holding and cooling stages of pretreatments to allow the exact size and nature of lignin aggregates to be controlled in order to enhance enzyme accessibility to cellulose and therefore the efficiency of biomass conversion.

This is a preview of subscription content, access via your institution.

Fig. 1
Fig. 2
Fig. 3
Fig. 4


  1. Cheng G, Varanasi P, Li C, Liu H, Melnichenko YB, Simmons BA, Kent MS, Singh S (2011) Transition of cellulose crystalline structure and surface morphology of biomass as a function of ionic liquid pretreatment and its relation to enzymatic hydrolysis. Biomacromolecules 12:933–941

    Article  CAS  Google Scholar 

  2. Langan P, Evans BR, Foston M, Heller WT, O’Neill HM, Petridis L, Pingali SV, Ragauskas AJ, Smith JC, Davison B (2012) Neutron technologies for bioenergy research. Ind Biotechnol 8(4):209–216

    Article  CAS  Google Scholar 

  3. Langan P, Petridis L, O’Neill HM, Pingali SV, Foston M, Nishiyama Y, Schulz R, Lindner B, Hanson BL, Harton S, Heller WT, Urban V, Evans BR, Gnanakaran S, Ragauskas AJ, Smith JC, Davison B (2014) Common Processes Driving the Thermochemical Pretreatment of Lignocellulosic Biomass. Green Chemistry 16:63–68

  4. Li C, Cheng G, Balan V, Kent MS, Ong M, Chundawat SPS, daCosta Sousa L, Melnichenko YB, Dale BE, Simmons BA, Singh S (2011) Influence of physico-chemical changes on enzymatic digestibility of ionic liquid and AFEX pretreated corn stover. Bioresour Technol 102:6928–6936

    Article  CAS  Google Scholar 

  5. Melnichenko YB, Kiran E, Wignal GD, Heath KD, Salaniwal S, Cochran HD, Stamm M (1999) Pressure- and temperature-induced transitions in solutions of poly(dimethylsiloxane) in supercritical carbon dioxide. Macromolecules 32:5344–5347

    Article  CAS  Google Scholar 

  6. Nishiyama Y, Langan P, O’Neill HM, Pingali SV, Harton S (2013) Structural coarsening of aspen wood by hydrothermal pretreatment monitored by small- and wide-angle scattering of X-rays and neutrons on oriented specimens. Cellulose. doi:10.1007/s10570-013-0069-2

  7. Pingali SV, Urban VS, Heller WT, McGaughey J, O’Neill HM, Foston M, Myles DA, Ragauskas A, Evans BR (2010) Breakdown in cell wall nanostructure in dilute acid pretreated biomass. Biomacromolecules 11:2329–2335

    Article  CAS  Google Scholar 

  8. Sannigrahi P, Ragauskas AJ, Tuskan GA (2010) Poplar as a feedstock for biofuels: a review of compositional characteristics, Biofuels. Bioprod Biorefin 4:209–226

    Article  CAS  Google Scholar 

Download references


This research is funded by the Genomic Science Program, Office of Biological and Environmental Research, U.S. Department of Energy, under FWP ERKP752. The Center for Structural Molecular Biology (CSMB) and the Bio-SANS beam line is supported by the Office of Biological and Environmental Research, using facilities supported by the U. S. Department of Energy, managed by UT-Battelle, LLC under contract No. DE-AC05-00OR22725. This Research on Bio-SANS and GP-SANS at Oak Ridge National Laboratory’s High Flux Isotope Reactor was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, US Department of Energy.

Author information



Corresponding author

Correspondence to Sai Venkatesh Pingali.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Pingali, S.V., O’Neill, H.M., Nishiyama, Y. et al. Morphological changes in the cellulose and lignin components of biomass occur at different stages during steam pretreatment. Cellulose 21, 873–878 (2014).

Download citation


  • Neutron scattering
  • Steam pretreatment
  • Cellulose
  • Lignin
  • Biomass
  • Biofuels