Abstract
We explore the efficacy of depolymerization as a function of lignin source and extraction method under the conditions of our previously described biorefinery. Biomass source (i.e. herbaceous, softwood, and hardwood) influences the total available lignin and structural features such as the ratio of monomers (S/G) and the percentage of β-O-4 linkage. The method of extraction (i.e. Milled Wood (mild), Organosolv (medium), and Klason (harsh)) determines levels of solubilization, preservation of the intrinsic lignin structure, and distribution and properties of products. Herbaceous lignin extracted by the Organosolv process is best suited for depolymerization in our biorefinery and shows the greatest extent of solubilization (∼100% over 7 days), the highest yields of phenolics and flavonoids, and the most and smallest lignin nanoparticles. Additionally, this depolymerized product mixture has the highest antioxidant capacity. Only the harsh, Klason method successfully isolates lignin, through carbohydrate conversion, from all three sources, but the herbaceous and hardwood sources are depolymerized to a lesser extent than by the Organosolv method. With low density of labile bonds, softwood lignin is not effectively depolymerized under these conditions. Although modifying intrinsic lignin structure the least, Milled Wood lignin does not efficiently extract lignin from any of the biomass, and the extracted lignin is low in purity inhibiting further processing. These results further detail the promise of herbaceous Organosolv lignin as a renewable feedstock to high value products in a distributed-scale biorefinery.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 2328-2340 |
| Number of pages | 13 |
| Journal | RSC Sustainability |
| Volume | 1 |
| Issue number | 9 |
| DOIs | |
| State | Published - Oct 27 2023 |
Funding
Funding for this work was provided by the Finite Earth Initiative of the McCormick School of Engineering at Northwestern University. Biological and chemical analysis was performed in the Analytical bioNanoTechnology Core Facility of the Simpson Querrey Institute at Northwestern University. The U.S. Army Research Office, the U.S. Army Medical Research and Materiel Command, and Northwestern University provided funding to develop this facility and ongoing support is being received from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-1542205). This work made use of the IMSERC MS facility at Northwestern University, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-2025633), and Northwestern University. This work also made use of the EPIC facility of Northwestern University's NUANCE Center, which has received support from the SHyNE Resource (NSF ECCS-2025633), the IIN, and Northwestern's MRSEC program (NSF DMR-1720139).
ASJC Scopus subject areas
- Chemistry (miscellaneous)
- Analytical Chemistry
- Electrochemistry
- Organic Chemistry