Effects on Lignin Redistribution in Eucalyptus globulus Fibres Pre-Treated by Steam Explosion: A Microscale Study to Cellulose Accessibility

Biomolecules. 2021 Mar 29;11(4):507. doi: 10.3390/biom11040507.


The objective of this study was to investigate structural changes and lignin redistribution in Eucalyptus globulus pre-treated by steam explosion under different degrees of severity (S0), in order to evaluate their effect on cellulose accessibility by enzymatic hydrolysis. Approximately 87.7% to 98.5% of original glucans were retained in the pre-treated material. Glucose yields after the enzymatic hydrolysis of pre-treated material improved from 19.4% to 85.1% when S0 was increased from 8.53 to 10.42. One of the main reasons for the increase in glucose yield was the redistribution of lignin as micro-particles were deposited on the surface and interior of the fibre cell wall. This information was confirmed by laser scanning confocal fluorescence and FT-IR imaging; these microscopic techniques show changes in the physical and chemical characteristics of pre-treated fibres. In addition, the results allowed the construction of an explanatory model for microscale understanding of the enzymatic accessibility mechanism in the pre-treated lignocellulose.

Keywords: Eucalyptus globulus; FT-IR imaging; chemometric analysis; enzymatic hydrolysis; lignin droplets; steam explosion.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cellulase / metabolism
  • Eucalyptus / metabolism*
  • Hydrolysis
  • Lignin / chemistry
  • Lignin / metabolism*
  • Microscopy, Confocal
  • Principal Component Analysis
  • Spectroscopy, Fourier Transform Infrared
  • Temperature


  • Lignin
  • Cellulase