Fungi’s ability to digest contaminated plastics, oil spills, toxic waste and even cleanse the natural environment from radiation is garnering attention around the world.
Investors are foreseeing a fungus-powered future: U.S. bioremediation company Mycocycle raised $3.6 million in May 2024 to use fungi to clean up construction waste, while Belgian biotech company Novobiom raised €1.97 million ($2.23 million) in April 2024 to use its mycelium-based technology to clean up contaminated soil.
Fungal hyphae extend underground and are an effective way for environmental and indigenous groups to purify soil and water. Photo credit: Justin Long / Alamy Stock Photo
Bioremediation, an environmentally friendly technique that uses living organisms to remove recalcitrant industrial toxins from soil, water, and other contaminated environments, is experiencing rapid growth. The global bioremediation market is expected to be worth $13.8 billion in 2022 and reach $28.9 billion by 2030. In particular, fungus-based remediation has attracted the most attention (Table 1). The goal is to purify contaminants, such as sewage sludge on agricultural land, the aftermath of industrial spills, construction waste, and heavy metals, by having mycelium feed on them, leaving only harmless by-products.
Table 1. Selected comedy companies
Mycelium is the body of fungi, often found underground as a root-like filament or network of hyphae, while the familiar mushrooms are the apple-like fruiting bodies on trees. The strength, flexibility and biodegradability of mycelium make it a highly versatile material, already used as alternative leather for bags and clothing, degradable eco-packaging and even interior architecture. Its texture and density also make it an attractive meat substitute.
“Fungi is an unexplored field,” says Suzanne Groersen, founder of the Future is Fungi Award, which is given to startups that develop innovative solutions using mycelium. [we] We can do more with it. This is the final frontier in biological discovery.”
Mycologist Paul Stamets began experimenting with mycelium’s purification powers in the 1980s, when he set up outdoor mycelium beds to purify wastewater from his small cattle herd. Since then, he has worked with the US Department of Defense to purify the neurotoxin DMMP used by Iraq in the Gulf War using enzymes produced by two “white rot” fungi. UK-based activist and documentary maker Nicola Peel used fungi to clean up the Chevron oil spill in the Ecuadorian Amazon, while others have applied fungal purification solutions to purify water after the 2007 COSCO Pusan oil spill in San Francisco Bay and California wildfires. Now, startups are backed by investors as they look to scale up these natural solutions.
American company Mycocycle upcycles used tires and removes toxins from industrial waste. Joan Rodriguez, a former sustainability director for a construction company, understood the waste problem the construction industry creates. The US Environmental Protection Agency estimates that 540 million tonnes of construction and demolition waste were generated in the US in 2018. Rodriguez founded the company in 2020 to harness fungi’s ability to break down heavy hydrocarbons and convert them into useful bio-based materials.
The mycelium breaks down gypsum (calcium sulfate dihydrate, mainly used in plaster), carpet, and rubber. Customers are given containers with water and wood chips to feed the mycelium and create the right conditions for white-rot fungi to grow. The waste is then mixed into a bioreactor, where enzymes produced by the mycelium break down styrene-butadiene bonds in carpet and other waste materials. This process keeps gypsum board from ending up in landfills, prevents it from releasing hydrogen sulfide gas when wet, and prevents the release of butadiene, an irritant, into the environment. The decomposition is complete in two weeks, and what remains is a composite of the mycelium and the original material, a homogenous mixture of materials that can be used as filler, fiber, or foam. The company says that for every tonne of waste it processes, it can reduce CO2 emissions by three tons. One of its customers is Meta, which it recently helped demolish scrap drywall left over from the construction of a data center.
Contaminated land is another area where decomposing fungi are making a difference: More than 70 percent of the world’s land is degraded, and that percentage could rise to 90 percent by 2050, according to a report by the European Commission Joint Research Centre. Novobiom, based in Ottignies-Louvain-la-Neuve, Belgium, uses mycelium to clean up contaminated industrial soils. Clients include waste treatment company Veolia and brownfield remediation company Vargo.
The Belgian company Novobiom carries out mycoremediation in contaminated industrial areas. The company mixes contaminated soil with hyphae of basidiomycetes and ascomycetes to form biopiles where humidity and temperature can be controlled. This process reduces the concentration of contaminants below thresholds set by environmental authorities, and the cleaned soil cannot be used for agriculture, but can be safely reused for road construction, for example. Novobiom has already demonstrated that the process works on a large scale, carrying out two pilot projects to clean up soil in industrial areas in France and Belgium. The decontamination deals with high molecular weight polycyclic aromatic hydrocarbons containing up to six rings, benzene, toluene, ethylbenzene and xylene.
Novobiom currently combines 25 different mycelium strains to customize solutions for each customer’s soil and microbiome characteristics. The company takes into account soil quality, carbon nutrients, nitrogen, minerals and oxygen, and if limitations are found, it can fine-tune the fungal treatment needed to remediate the soil. “At the moment, the soil microbial standard is a fixed list of the most representative features of bacteria in soil,” says Novobiom co-founder Caroline Zaoui. “But we’re aiming for a more customized representation, especially for contaminated soils.”
Bacteria can also be used for bioremediation, but results are more mixed. Zaoui says fungi are more effective because they rely on both extracellular and intracellular enzymes to break down mineral oil, but bacteria need to come into close contact with the contaminant and internalize it to break it down. “The longer the hydrocarbon chain, the harder it is for the bacteria to get the molecule inside,” Zaoui said, adding, “The bacteria are so small that they can’t move toward the contaminant. They can’t move through the mycelium.” [create] By building a network within the soil, we can explore the soil and get closer to the contaminants.”
Novobiom is also partnering with French recycling company Ecomaison on a research and development project to help dispose of mattresses. Five million mattresses are sold in France every year, but their lifespan is only 10 years. Ecomaison, which is backed by the French government, can upcycle the latex, polyurethane foam and springs of mattresses, but not mattress covers, because they contain a mix of natural and synthetic fibers. Novobiom’s fungi can enzymatically process natural fibers (cellulose or proteins) into sugars and amino acids, leaving behind polyester. “We’re still a long way from industrialization, but this project is a real opportunity, and we’re funding it and providing a large amount of the fiber mix,” says Gwendal Michel, research and development manager at Ecomaison.
Iranian researchers from Bu-Alsina University isolated strains of bacteria that grow in oil-contaminated soil at the Arak oil refinery. The field study examined the enzyme efficiency of four strains of the genera Achromonium, Alternaria, Aspergillus terreus, and Penicillium. Two of these strains produced the enzymes catalase, peroxidase, and phenoloxidase, which were able to reduce the oil levels in pots of contaminated soil by more than half. The Indian study also found that lignin-degrading enzymes released by some fungi can break down polycyclic aromatic hydrocarbons.
Stockholm-based MycoMine is developing a portable water treatment plant that uses fungi to remove hydrocarbons. MycoMine won the Best Startup award at the 2023 Future is Fungi Awards, together with Novobiom.
After searching for extremophiles in the deep sea and hydrothermal systems, Mycomine co-founder Magnus Ivarsson found what he was looking for in the Stockholm subway: fungi that use oil for fuel. “When we looked at them under a microscope, we could see how the fungi were storing oil droplets inside their cells. That gave us the idea that we could scale this up and use it to clean up the environment. [problems]” says Ivarsson.
MycoMine developed small bioreactors called MycoCubes packed with fungi to remove oil and diesel from water. The fungal cytochrome p450 enzyme breaks down toxic n-alkane hydrocarbons into small compounds that the fungi can absorb and use as food. In 2022, they used the portable treatment plant in a pilot project in an abandoned mine contaminated with oil. The fungal bioreactor purified one cubic meter every 20 days. Although the process is slow, the water in the mine is now of almost drinking water quality. This is a dramatic improvement over previous methods that involved purifying water by incineration, which releases carbon dioxide into the atmosphere and leaves a sludge that is disposed of in landfills.
Even plastics, which are ultimately made from petroleum, are susceptible to fungal degradation. London-based biomanufacturing company Biom turned its attention to plastic degradation in 2018 after the mycelium it was researching consumed plastic sponges that sealed container jars. Biom currently uses fungi to process polyurethane, polystyrene, and polyester. While most companies that claim to degrade plastic waste focus on putting plastic to second use, Biom aims to dispose of plastic in a circular system. Carbon dioxide is released as fungal enzymes break down the waste into hydrocarbons and sugars, and Biom pairs this platform with photosynthetic plants that absorb the carbon dioxide and produce oxygen. This, in turn, feeds the bioreactor, or incubation chamber, where the fungi are grown.
Biome found that white-rot fungi that break down lignin are not entirely successful at breaking down plastic. Those that can are mutating in some way in response to the plastic material in their environment. In 2017, Pakistani researchers discovered the plastic-eating fungus Aspergillus tubingensis in a waste dump in Islamabad. In 2023, researchers at the University of Sydney looked at how some fungi use extracellular enzymes to break down complex polymer structures into smaller units, which they then use as a carbon source. A recent study found marine fungi eating plastic on a pile of floating plastic in the Great Pacific Garbage Patch. The fungus Parengiodontium album was specifically able to accelerate the decomposition of polyethylene exposed to ultraviolet light, a material most commonly used to make plastic bottles and other consumer goods.
Each fungus seems to specialize in the type of plastic it breaks down, and Biome has even created what amounts to a fungal production line: as one fungus finishes a task, another completes the next stage. Biome now plans to run a larger pilot project focused on breaking down tons of plastic. “We’ve only just scratched the surface in terms of fully understanding what fungi are capable of,” says Ehab Said, Biome’s chief evolution officer.
“Fungi occur naturally, so in most cases they pose no threat to the natural environment,” says Geoff Oberbard, a climate change consultant at Cranfield University in the U.K. But Oberbard adds that the process takes time.[As] “When fungi take advantage of natural decomposition processes, it takes longer than other chemical and physical remediation methods, and if the introduced fungi are not indigenous, they will compete with native microbes.”
While natural decomposition may be slower than chemical solutions, fungal remediation companies are committed to showing that using fungi is an economical and environmentally friendly strategy for tackling global pollution problems.
