Magic mushrooms

They can break down pesticides, synthetic dyes, and even explosives. They can live on used diapers, cigarette butts, crude oil, and in the most radioactive environments. They’re mushrooms, and the budding mycoremediation industry is putting them to work to help save the world.

Mycoremediation is the mushroom-focused subset of bioremediation, the application of biological agents like plants, algae, bacteria, and fungi to deal with environmental pollution. Spurred in part by visionaries like mycologist Paul Stamets, whose 2008 TED talk “6 ways mushrooms can save the world” has been watched millions of times, the growing field of mycoremediation is using mushrooms to take on chemical pollutants, heavy metals, and even toxic waste.

When catastrophic forest fires rage uncontained across North America and Europe, homes, summer campsites, and even villages can be swept up in the destruction. Along with wood, glass, and concrete, the incinerated mess left behind includes plastics, chemicals, and heavy metals like lead and mercury that, with the first rains, can end up in streams, lakes, and oceans, especially as a result of the accelerated soil erosion that comes after a fire. The traditional approach to remediation involves tractoring up masses of contaminated soil, hauling it away, and burning it.

But post-fire mycoremediation may offer a better alternative. Fungi produce enzymes capable of digesting even these most toxic chemicals, converting them into food that the fungi can eat.

It’s a trick they learned tens of millions of years ago, when fungi became the first organisms capable of breaking down lignin, the structural polymer that makes wood as tough as it is. The world without mushrooms was literally buried in non-decomposing plant material – the same material that was compressed over millions of years to form what we now know as fossil fuels. But the world as we know it started when mushrooms developed the ability to break down lignin – and most everything else. They’re the world’s natural decomposers – literally, the world’s stomach.

While the big knob-like or dish-shaped heads of mushrooms are only the part we see, the fruiting bodies of a mycelium, a network of microscopic cells that weaves together to form the basis of our soil. It’s these mycelium networks that have been shown capable of filtering E. coli bacteria out of contaminated water, and the same are being planted to trap the toxic ash runoff after forest fires.

Oil, whose hydrocarbon bonds present a similar challenge to lignin, is another target for mycoremediation. Pleurotus mycelium has been shown to break down these bonds and transform them into carbohydrates, food for mushrooms and insects, which in turn feed plants, letting us imagine the possibility of quickly regenerating an oil spill into a budding ecosystem.

Mushrooms have evolved to break down just about anything. Chernobyl scientists were amazed to discover a certain type of mushroom thriving in the highly radioactive environment in the destroyed reactor 4. However, getting them to break down exactly what we want, when we want, is a practice still in its infancy. Ecosystems matter, and the ideal solution would be finding mushrooms already growing near disaster sites that could do the job, though this requires extensive testing and then the effort to scale solutions. While the best solution would simply be limiting the toxic problems at the source, the next best may be to help mushrooms best work their magic, as they have been doing for millions of years.