WARF: P190134US01

  • Patent applied for.

One-Step Process to Generate Lignin-Derived Aromatics from Raw Biomass


Shannon Stahl, Hao Luo

The Wisconsin Alumni Research Foundation (WARF) is seeking commercial partners interested in developing a “lignin-first” method for generating valuable aromatics from raw biomass. This technology, by breaking lignin into valuable monomers directly, provides a lower-cost way of supplying materials for bio-based polymers.
OVERVIEWLignocellulosic biomass is a renewable energy source with great potential for generating value-added chemicals. One of the major components of biomass is lignin (15-25 percent). Due to its infamously complex structure, lignin is typically treated as waste and burned for its heat value.

Yet lignin is the largest renewable source of aromatic building blocks in nature, and has huge potential for generating valuable aromatic compounds for use in transportation fuels, bio-based polymer materials and other chemicals. In the past few decades, various lignin depolymerization strategies have been developed for this purpose.

Among the various strategies, oxidative depolymerization presents advantages in making aromatic compounds with oxygen-containing functional groups, but most are optimized for carbohydrate recovery. However, such processes result in low recovery and damage to the lignin structure. Strategies that enable efficient oxidative depolymerization of lignin in intact, untreated biomass are highly desirable.
THE INVENTIONUW–Madison researchers have developed a one-step, “lignin-first” method for generating lignin-derived aromatics from raw biomass. The new approach uses transition metal-based heterogeneous catalysts under neutral pH conditions with O2 as the oxidant. Compared to traditional biomass deconstruction approaches, which first isolate lignin from the feedstock before further processing for recovery of sugars, the lignin-first method avoids the cumbersome and destructive lignin extraction process.

While not optimized for sugar recovery, the carbohydrate residues are not degraded and remain intact for further processing.
BUSINESS OPPORTUNITYAccording to BCC research, the non-energetic bioproducts market should reach $477B by 2021. Some of these currently available bioproducts include plastics such as bio-based polyethylene and polylactic acid. Companies such as Braskem, Cargill and Verbio all have made investments in the space and have operating biorefineries. Previous attempts at valorizing lignin generally required broken lignin to undergo further transformations to yield valuable products. This technology, by breaking lignin into valuable monomers directly, provides a lower-cost way of supplying materials for bio-based polymers.
  • Biomass fractionation and the production of lignin-derived aromatic compounds
  • Results in >30 percent yield of selected aromatic compounds
  • Catalysts can be reused for at least seven cycles with relatively high activity
  • Use of acetone as an ecofriendly solvent significantly reduces operational costs
  • Highly efficient
  • Keeps carbohydrate residues intact for further use (e.g., in fermentation)
STAGE OF DEVELOPMENTThe method has been applied to raw biomass feedstock under mild/neutral pH conditions, thereby maximizing lignin recovery while reducing unwanted damage to the sugars/lignin. Moreover, catalyst recycling is possible due to the use of a catalyst cage, which separates the catalyst from the substrate and products. As a result, a clean (solid) carbohydrate stream is generated that can be easily separated from the aromatics for further processing.
Contact Information
For current licensing status, please contact Jennifer Gottwald at or 608-960-9854.
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