Supramolecular self-assembled chaos: polyphenolic lignin's barrier to cost-effective lignocellulosic biofuels

Molecules. 2010 Nov 29;15(12):8641-88. doi: 10.3390/molecules15118641.

Abstract

Phenylpropanoid metabolism yields a mixture of monolignols that undergo chaotic, non-enzymatic reactions such as free radical polymerization and spontaneous self-assembly in order to form the polyphenolic lignin which is a barrier to cost-effective lignocellulosic biofuels. Post-synthesis lignin integration into the plant cell wall is unclear, including how the hydrophobic lignin incorporates into the wall in an initially hydrophilic milieu. Self-assembly, self-organization and aggregation give rise to a complex, 3D network of lignin that displays randomly branched topology and fractal properties. Attempts at isolating lignin, analogous to archaeology, are instantly destructive and non-representative of in planta. Lack of plant ligninases or enzymes that hydrolyze specific bonds in lignin-carbohydrate complexes (LCCs) also frustrate a better grasp of lignin. Supramolecular self-assembly, nano-mechanical properties of lignin-lignin, lignin-polysaccharide interactions and association-dissociation kinetics affect biomass deconstruction and thereby cost-effective biofuels production.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Review

MeSH terms

  • Biofuels / economics*
  • Biomass*
  • Cell Wall / chemistry
  • Cell Wall / metabolism
  • Flavonoids / chemistry*
  • Flavonoids / metabolism
  • Lignin / chemistry*
  • Lignin / metabolism
  • Phenols / chemistry*
  • Phenols / metabolism
  • Plants / chemistry*
  • Plants / metabolism
  • Polyphenols
  • Propanols / chemistry*
  • Propanols / metabolism

Substances

  • Biofuels
  • Flavonoids
  • Phenols
  • Polyphenols
  • Propanols
  • 1-phenylpropanol
  • Lignin