Formation and Identification of Lignin-Carbohydrate Complexes in Pre-hydrolysis Liquors

Biomacromolecules. 2023 Jun 12;24(6):2541-2548. doi: 10.1021/acs.biomac.3c00053. Epub 2023 Jun 2.

Abstract

The lignin-carbohydrate complexes (LCCs) typically present in the liquors produced in the pre-hydrolysis of biomass cause severe difficulties in downstream fractionation. To address this issue, a series of LCC samples were accessed from solutions obtained from the pre-hydrolysis of extractive-free pine wood meal (H-LCC) and compared with LCC obtained from the corresponding residues (B-LCC). Chromatographic and spectroscopic techniques revealed that 8.2% of the lignins were degraded at 160 °C, resulting from the breakage of β-O-4' linkages during pre-hydrolysis. Meanwhile, (reactive) hemicelluloses were mainly removed from the fibers' cell walls. Some hemicelluloses in the pre-hydrolysis liquor, such as glucomannans, were associated with degraded lignin fragments via ether and ester bonds. However, the newly formed LCCs were pH-labile and underwent rapid hydrolysis. Overall, we reveal details about LCC formation and degradation during pre-hydrolysis at given temperatures, critically important in efforts to improve biomass processing and valorization.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carbohydrates* / chemistry
  • Hydrolysis
  • Lignin* / chemistry
  • Magnetic Resonance Spectroscopy
  • Wood / chemistry

Substances

  • Lignin
  • Carbohydrates