Abstract
Lignin plays important biological functions in plant cell walls, but also contributes to the recalcitrance of the walls to deconstruction. In recent years, genetic modification of lignin biosynthesis pathways has become one of the primary targets of plant cell wall engineering. In this study, we used a combination of approaches to characterize the structural and compositional features of wild-type Arabidopsis and mutants with distinct lignin monomer compositions: fah1-2 (Guaiacyl, G-lignin dominant), C4H-F5H (Syringyl, S-lignin dominant), COMT1 (G/5-hydroxy G-lignin dominant), and a newly developed med5a med5b ref8 (p-hydroxyphenyl, H-lignin dominant) mutant. In order to understand how lignin modification affects biomass recalcitrance, substrate reactivity and lignin fractionation, we correlated these properties with saccharification efficiency after ionic liquid (IL) pretreatment. Results showed that the cleavage of β-O-4 linkages in the H- or S-lignin mutants was greater than that in G-lignin mutants. Furthermore, density functional theory (DFT) based calculations indicate higher chemical reactivity of the linkages between H- and S-lignin monomers, a possible cause of the reduced recalcitrance of H- or S-lignin mutants. Glycome profiling was conducted to study the impact of lignin modification on overall composition, extractability, integrity and lignin-associated features of most major non-cellulosic cell wall glycans in these mutants. This study provides insights into the role of lignin monomer composition on the enzymatic digestibility of biomass and the effect of lignin modification on overall wall structure and biomass pretreatment performance.
| Original language | English |
|---|---|
| Pages (from-to) | 4884-4895 |
| Number of pages | 12 |
| Journal | Green Chemistry |
| Volume | 18 |
| Issue number | 18 |
| DOIs | |
| State | Published - 2016 |
Bibliographical note
Funding Information:Work conducted at the Joint BioEnergy Institute was supported by the Office of Science, Office of Biological and Environmental Research, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 and through the Center for Direct Catalytic Conversion of Biomass to Biofuels (C3Bio), an Energy Frontier Research Center funded by the U.S. DOE, Office of Science, Office of Basic Energy Sciences, Award number DE-SC0000997. The glycome profiling was supported by the BioEnergy Science Center administered by Oak Ridge National Laboratory, and funded by a grant (DE-AC05-00OR22725) from the Office of Biological and Environmental Research, Office of Science, United States, Department of Energy. The generation of the CCRC series of plant cell wall glycan-directed monoclonal antibodies used in this work was supported by the NSF Plant Genome Program (DBI-0421683 and IOS-0923992). This research used resources of the National Energy Research Scientific Computing Center and EMSL at Pacific Northwest National Laboratory. We thank Dr Noppadon Sathitsuksanoh and Dr Jeffrey Pelton for help on NMR and SEC analysis. We also acknowledge the National Science Foundation under Cooperative Agreement No. 1355438 for partially supporting the effort at University of Kentucky.
Publisher Copyright:
© The Royal Society of Chemistry 2016.
ASJC Scopus subject areas
- Environmental Chemistry
- Pollution