Title: Multidimensional NMR analysis reveals truncated lignin structures in wood decayed by the brown rot basidiomycete Postia placenta
Author: Yelle, Daniel J.; Wei, Dongsheng; Ralph, John; Hammel, Kenneth E.
Source: Environmental microbiology. Vol. 13, no. 4 (2010): p. 1091-1100.
Description: Lignocellulose biodegradation, an essential step in terrestrial carbon cycling, generally involves removal of the recalcitrant lignin barrier that otherwise prevents infiltration by microbial polysaccharide hydrolases. However, fungi that cause brown rot of wood, a major route for biomass recycling in coniferous forests, utilize wood polysaccharides efficiently while removing little of the lignin. The mechanism by which these basidiomycetes breach the lignin remains unclear. We used recently developed methods for solubilization and multidimensional 1H–13C solution-state NMR spectroscopy of ball-milled lignocellulose to analyse aspen wood degraded by Postia placenta. The results showed that decay decreased the content of the principal arylglycerol-β-aryl ether interunit linkage in the lignin by more than half, while increasing the frequency of several truncated lignin structures roughly fourfold over the level found in sound aspen. These new end-groups, consisting of benzaldehydes, benzoic acids and phenylglycerols, accounted for 6–7% of all original lignin subunits. Our results provide evidence that brown rot by P. placenta results in significant ligninolysis, which might enable infiltration of the wood by polysaccharide hydrolases even though the partially degraded lignin remains in situ. Recent work has revealed that the P. placenta genome encodes no ligninolytic peroxidases, but has also shown that this fungus produces an extracellular Fenton system. It is accordingly likely that P. placenta employs electrophilic reactive oxygen species such as hydroxyl radicals to disrupt lignin in wood.
Keywords: Wood-decaying fungi, brown rot, lignocellulose, biodegradation, Basidiomycetes, lignin, aspen, microbial metabolism, Postia placenta, polysaccharides, nuclear magnetic resonance spectroscopy, Populus, benzaldehyde, benzoic acid, hydrolases, wood deterioration, decay fungi, wood decay, phenylglycerol, ligninolysis, Fenton system, hydroxyl radicals, peroxidase
View or Print this Publication (1.6 MB)
- We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
- This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
Yelle, Daniel J.; Wei, Dongsheng; Ralph, John; Hammel, Kenneth E. 2011. Multidimensional NMR analysis reveals truncated lignin structures in wood decayed by the brown rot basidiomycete Postia placenta. Environmental microbiology. Vol. 13, no. 4 (2010): p. 1091-1100.
Get the latest version of the Adobe Acrobat reader or Acrobat Reader for Windows with Search and Accessibility