No one loves mushrooms as much as Ray Van Court loves mushrooms.

Their favorite food? Matsutake mushrooms. Their favorite hobby? Mushroom hunting. Their favorite time of the year? Mushroom season.

In fact, Van Court loves mushrooms so much they quit their corporate job to pursue ways to make the world a better place through fungi.

As a PhD candidate in wood science and graduate research assistant, Van Court is working on a project with assistant professor of forest-based bio-products Gerald Presley. Together, they use ectomycorrhizal fungi to bioremediate heavy metal-treated wood waste.

“Preservatives are critical to retaining the structural integrity of wood, but disposal of treated wood is problematic,” Van Court says. “Wood treated with metals including arsenic and copper is disposed of in landfills, often unlined, where these toxic metals can move into the environment. Preventing the migration of these metals, and potentially recovering them, could reduce the ecological impact of these contaminants.”

Certain species of ectomycorrhizal fungi are known to tolerate high metal environments, and initial work has shown that they may reduce metal toxicity. These mechanisms include binding them, transporting them, and producing compounds that stabilize the metals. Introducing fungi particularly adept at immobilizing metals in contaminated sites could reduce the environmental impact of toxic metal migration. The resulting retention of bound metals may also allow for reclamation.

This, says Van Court, represents a long-term solution to the problem of treated wood waste with little required inputs – all ectomycorrhizal fungi need is trees to associate with.

To test this idea, Van Court and Presley are performing a multi-stage lab experiment, screening 20 different species of ectomycorrhizal fungi in plate culture against three toxic metals.

“This screening will identify which species best tolerate and uptake metals used in wood preservatives and is an enormous increase in species and metals compared to previous research,” says Van Court.

In the second stage of the research, trees will be inoculated with the best performing fungi and planted in heavy metal-treated mesocosms, controlled containers that replicate natural environments. Trees and fungi will grow together in the metal contaminated system for a few months, after which their effect on metal will be measured. This initial work will test the effectiveness of the fungal system and pave the way for future field research.

While doing the research, Van Court was surprised by the scarcity of technologies related to ectomycorrhizal fungi and the limited knowledge on fungi growth. The fungi are usually in symbiosis with trees and for many species very little is known regarding how to replicate what the tree or other organisms in the ecosystem typically provide to the fungus.

“Admittedly, they are much harder to grow and maintain than decay fungi, but they represent a lot of untapped potential,” Van Court says. “As all kinds of products – from medicines to packaging material – have come from decay fungi, what new sustainable products might come from ectomycorrhizal ones? With new analytical and genetic tools, I think we are poised to learn much more about these fungi, and I am excited to see where this research and other projects can go.”

A version of this story appeared in the Spring 2022 issue of Focus on Forestry, the alumni magazine of the Oregon State University College of Forestry.