Extraction of High-Purity Lignins via Catalyst-free Organosolv Pulping from Low-Input Crops

Biomacromolecules. 2020 May 11;21(5):1929-1942. doi: 10.1021/acs.biomac.0c00123. Epub 2020 Mar 24.


A catalyst-free organosolv pulping process was applied to cup plant (Silphium perfoliatum, S), Miscanthus grass (Miscanthus x giganteus, M), and the Paulownia tree (Paulownia tomentosa, P), resulting in high-purity lignins with no signals for cellulose, hemicellulose, or other impurities in two-dimensional heteronuclear single quantum coherence (HSQC) nuclear magnetic resonance (NMR) spectra. Different biomass particle sizes used for the organosolv pulping (1.6-2.0 mm (1); 0.5-1.0 mm (2); <0.25 mm (3)) influenced the molecular weight and chemical structure of the isolated lignins. Principal component analysis (PCA) of 1H NMR data revealed a high intergroup variance of Miscanthus and Paulownia lignins, separating the small particle fraction from the larger ones. Furthermore, monolignol ratios identified via HSQC NMR differ significantly: Miscanthus lignins were composed of all three monolignols (guaiacyl (G), p-hydroxyphenyl (H), syringyl (S)), while for Paulownia and Silphium lignins only G and S units were observed (except for P3).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biomass
  • Cellulose
  • Lignin*
  • Poaceae*
  • Spectroscopy, Fourier Transform Infrared


  • Cellulose
  • Lignin