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ARS Home » Midwest Area » Madison, Wisconsin » U.S. Dairy Forage Research Center » Research » Publications at this Location » Publication #152485

Title: SOLUBILIZATION OF FINELY-DIVIDED CELL WALLS-A PLATFORM FOR IMPROVED CHARACTERIZATION AND ANALYSIS

Author
item LU, FACHUANG - UW-MADISON
item Ralph, John

Submitted to: Gordon Research Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 6/3/2003
Publication Date: 8/10/2003
Citation: LU, F., RALPH, J. SOLUBILIZATION OF FINELY-DIVIDED CELL WALLS-A PLATFORM FOR IMPROVED CHARACTERIZATION AND ANALYSIS. GORDON RESEARCH CONFERENCE PROCEEDINGS. 2003. Abstract paper 23.

Interpretive Summary:

Technical Abstract: The ability to dissolve whole plant cell walls without degradation of the components is a currently unrealized holy grail for plant analysis. Solid samples are amenable to an array of spectroscopic methods, but none bearing nearly the resolution and diagnostic power of solution-state NMR. And various wood reactions are encumbered by its heterogeneous nature. Imagine being able to dissolve wood (and other plant cell walls) in a reasonably innocuous solvent system? Now chemists are back in the familiar realm of solution-state chemistry, and all of the experiments possible in high-resolution NMR become accessible. The possibilities are mind-boggling. We can finally envision NMR studies on more than just the often-low yields of dioxane:water soluble lignins that can be extracted by Björkman's procedure, for example. Derivatization reactions could be carried out to completion without the limitation of reagent penetration into the fibers. As an example, one of the most valuable lignin analyses is thioacidolysis following complete phenol-methylation; this analysis yields monomers and dimers where those resulting from etherified units in the lignin are distinguished from free-phenolic end-units (and provides data to explain pulping efficacy, for example). Currently, the methylation step however requires extensive and prolonged treatment with diazomethane, e.g., a dozen treatments over some 2 weeks. In solution, however, phenol methylation is rather simple to accomplish. We now have two dissolution systems that work on ball-milled plant cell walls. To date we have taken pine, aspen, and corn cell walls and fully dissolved them in the solvent (overnight at room temperature!). Acetylation produces fully acetylated cell walls with no apparent degradation; the acetylated walls are fully soluble in common organic solvents and 2D NMR spectroscopy readily reveals the traditional lignin structures amongst the dominant polysaccharide resonances. Phenol methylation has so far just been demonstrated with hydroxycinnamates on corn, but can be effected to a 98% level in about 10 mins, and completely (as far as we can tell) in an hour. This method alone already promises to revolutionize hydroxycinnamates analysis.