Isolation and characterization of Gramineae and Fabaceae soda lignins

Juan Domínguez-Robles, Rafael Sánchez, Eduardo Espinosa, Davide Savy, Pierluigi Mazzei, Alessandro Piccolo, Alejandro Rodríguez*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

31 Citations (Scopus)
35 Downloads (Pure)


Some agricultural residues such as wheat or barley straw, as well as certain fast-growing plants like Leucaena leucocephala and Chamaecytisus proliferus, could be used as raw materials for the paper industry as an alternative to traditional plants (eucalyptus, pine, etc.). In the present study, four types of lignin obtained from the spent liquors produced by the pulping processes using the abovementioned feedstocks were isolated and characterized. Lignin samples were acquired through an acid precipitation from these spent liquors. The characterization of the precipitated lignin samples were performed using a Fourier transform infrared spectroscopy (FT-IR) and both liquid- and solid-state nuclear magnetic resonance spectroscopy (NMR) to analyse the chemical structure, and thermogravimetric analysis (TGA) for determining the thermal properties. Additionally, chemical composition of lignin fractions was also measured. Even though they were of different botanical origin, all the studied samples except for wheat straw lignin had a similar chemical composition and thermal behaviour, and identical chemical structure. Wheat straw lignin showed a greater amount of Klason lignin and lower carbohydrate content. Furthermore, this lignin sample showed a higher thermal stability and significantly different cross-peak patterns in the 2D-NMR experiments. The molecular structures corresponding to p-coumarate (PCA), ferulate (FA) and cinnamyl aldehyde end-groups (J) were only detected in wheat isolated lignin.

Original languageEnglish
Pages (from-to)1-17
JournalInternational journal of molecular sciences
Issue number2
Publication statusPublished - 04 Feb 2017
Externally publishedYes


  • Agricultural residues
  • Alkaline extraction
  • Physico-chemical properties
  • Soda lignin
  • Spent liquors
  • Structural elucidation

ASJC Scopus subject areas

  • Catalysis
  • Molecular Biology
  • Computer Science Applications
  • Spectroscopy
  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry


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