Alkaline Oxidation of Enzymatic Hydrolysis Lignin Using Reversibly Soluble Bases

Jacob Kruger, David Brandner, Camille Amador, Katherine Krouse, Daniel Wilcox, Gregg Beckham

Research output: NRELPresentation


Production of aromatic aldehydes, such as vanillin, from lignin, has been an intriguing process for decades, but widespread implementation has been inhibited by the high hydroxide:lignin ratios required for significant aldehyde yields. In this work, we explore oxidation of lignin-rich residues isolated from corn stover after deacetylation, mechanical refining, and enzymatic hydrolysis (DMR lignin), using reversibly-soluble bases in place of NaOH. In particular, strontium and barium hydroxides have low solubility at room temperature, but become soluble to more than 2 M at temperatures above 100 °C, thus producing highly alkaline conditions at reaction temperature but facilitating a simple recovery and recycle of the alkali upon cooling. Aromatic monomer yields are comparable for both types of bases at 20-30 wt%, depending on the lignin substrate. Overall, these results suggest a strategy to substantially reduce the cost and life cycle impact of lignin depolymerization by alkaline oxidation.
Original languageAmerican English
Number of pages18
StatePublished - 2020

Publication series

NamePresented at the 2020 Bioenergy Sustainability Conference, 13-15 October 2020

NREL Publication Number

  • NREL/PR-2800-78152


  • alkaline
  • lignin
  • oxidation
  • strontium


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