Novel Fungal-Based Method for Carbon Fiber Recovery

An international group of researchers from the University of Kansas and the University of Southern California has developed a chemical process to dissolve and extract the matrix from Carbon Fiber Reinforced Polymers (CFRPs). This process allows recovered carbon fiber plies to retain mechanical properties similar to those of virgin manufacturing substrates. The study was published in the Journal of the American Chemical Society.

Carbon fiber is used in a wide range of products, from passenger airplanes to hockey sticks, with hundreds of thousands of tons produced globally each year. As a result, researchers have been exploring practical and cost-effective methods for recycling this material.

However, recycling carbon fiber strands—carbon atoms bound together in a matrix—into new, usable materials presents a significant challenge.

It is usually a woven material combined with a matrix, often made of epoxy or polystyrene, that holds it together. You have a mixture of the fabric and the matrix, so the goal is to recover the fabric for reuse and also dissolve the matrix without creating something toxic or wasteful. Ideally, you want to reclaim value from it.

Berl Oakley, Irving S. Johnson Distinguished Professor, University of Kansas

To recover additional value, Oakley has developed a genetically modified strain of the fungus Aspergillus nidulans, which can consume benzoic acid and produce OTA (2Z,4Z,6E)-octa-2,4,6-trienoic acid, a valuable chemical compound. Benzoic acid is one of the main products of the matrix breakdown.

Oakley and his colleagues stated, “This represents the first system to reclaim a high value from both the fiber fabric and polymer matrix of a CFRP.”

We have been working for years with his lab to produce secondary metabolites in Aspergillus nidulans. Secondary metabolites are compounds the fungus produces—penicillin is the archetypal secondary metabolite—that have biological activity, like inhibiting its competitors and so on. The Asperlin pathway is something that came out of that work. Asperlin is a secondary metabolite. We managed to turn on a particular pathway, and that was the product. We discovered that OTA is an intermediate in the pathway and OTA is a potentially valuable industrial compound.

Berl Oakley, Irving S. Johnson Distinguished Professor, University of Kansas

Clay Wang, Study Lead Author, University of Southern California, noted: “OTA can be used to make products with potential medical applications, like antibiotics or anti-inflammatory drugs. This discovery is important because it shows a new, more efficient way to turn what was previously considered waste material into something valuable that could be used in medicine.”

Oakley added that for the new carbon-fiber recycling technique to be implemented on an industrial scale, his KU lab will work to enhance the effectiveness of their specialized fungus while also considering scalability and profitability requirements.

Since this work began, we have developed strains that are better than the original ones. These newer strains will likely give better results, but we will need to do lots of work to engineer this process into the improved strains.

Berl Oakley, Irving S. Johnson Distinguished Professor, University of Kansas

Cory Jenkinson, a Graduate Student at the University of Kansas, joined Oakley in the study. Clarissa Olivar, Zehan Yu, Ben Miller, Maria Tangalos, Steven Nutt, and Travis Williams were among Wang's Co-authors at the University of Southern California.

Journal Reference:

‌Olivar, C., et al. (2024) Composite Recycling with Biocatalytic Thermoset Reforming. Journal of the American Chemical Society. doi.org/10.1021/jacs.4c10838.