There are more than 5 million species of fungi, and each one likes a particular food. Some like sawdust. Others like plastic. Some can even digest heavy metals. After the fungi eat their meal, what was once waste turns into a new, natural and compostable material that can just be left to decompose or be used in all sorts of practical ways, from cleaning up oil spills to fashioning faux leather handbags to building houses. Sonia Travaglini, a Ph.D. candidate in mechanical engineering at UC Berkeley, tells us all about it.

Subscribe to Fiat Vox.

Fiat Vox on Berkeley News.

Following is a written version of Fiat Vox podcast episode #29: “From pollution cleanup to building houses, what can’t mushrooms do?:”

For Sonia Travaglini, mushrooms are her life.

“I would say fungi have been the hidden cousin to all of the more popular cousins and brothers in the biological world,” says Travaglini. “There is a blinding array of mushrooms in the world.”

She’s a Ph.D. candidate in mechanical engineering at UC Berkeley. Her research is all about developing and testing novel mushroom materials.

“So what we do is we get mushrooms that like to eat all sorts of things — they’re nature’s recyclers — and they like to eat all sorts of industrial wastes.”

There are more than 5 million species of fungi, and each one likes a particular food. Some like sawdust. Others like plastic. Some can even digest heavy metals. After the fungi eat their meal, what was once just waste turns into a new, natural and compostable material that can just be left to decompose or used in all kinds of practical ways.

The type of mushroom that Sonia works most closely with is the Ganoderma lucidum, also known as the Reishi mushroom. It’s been called “the mushroom of immortality.” When it’s not providing a magical cure for aging, it eats sawdust.

“Looking at this, you can actually see some sawdust in there. Is that right?” I ask.

“Exactly,” she says. “That’s because we decide exactly how much of the sawdust it eats.”

Here’s how it works: Say you’re at an industrial site where there’s a lot of sawdust waste. To get rid of it, you can sprinkle a couple spores from a Ganoderma lucidum into a pile of shavings.

“At first, you just see little tendrils growing out like the roots of a tree,” says Travaglini. “After a while, all these roots intermingle and link up and start to make the cellular material.”

If the fungi are allowed to gorge for several weeks, they’ll convert all the sawdust to mushroom flesh, creating a heavy, solid material that can withstand a lot of force, similar to wood. If they’re stopped before they’re full, say after just a week or two, they create a lighter material with a lot of sawdust still mixed in.

After it becomes the type of material that growers are looking for, they have to denature it.

“You have to kill the mushrooms,” says Travaglini.

To do this, they take the mushroom substance, put it in an oven and bake at 70 degrees centigrade or about 160 degrees Fahrenheit.

This new material can be made into different shapes — like small bricks. And it can be used for all sorts of things, like insulation in walls, packaging, building furniture — even as a leather substitute.

“Ultimately when you make products from animals it takes so much energy just to get there,” she says. “And of course it’s not very fair to the animals. So by using something that actually wants to get rid of waste for you because that’s what it loves to do — all of those sort of ethical questions are resolved. And you’re also putting in so much less energy, which means you’re not causing as much greenhouse gases and you’re sequestering carbon into those materials. You’re literally helping stopping the planet overheat.”

There are two companies in the country — MycoWorks in San Francisco and Ecovative in New York City — working to use fungi to create everything from faux leather handbags to wine coolers to packing supplies. For the past few years, UC Berkeley has been collaborating with Mycoworks to test the strength and durability of their products.

I think I can guess what’s on your minds — do all of these products smell like mushrooms? The answer is no, for a couple of reasons.

First, the materials aren’t actually made with mushrooms. They’re made from mycelium, which are like the roots of fungi — they don’t smell like the mushrooms you’d grow in your garden or buy at the store. The mushroom part is like the pungent fruit of the fungi.

And second, the material is denatured and dried, which leaves it nearly odorless. Sonia says it might smell a bit woodsy, but definitely not mushroomy.

The possibilities of using fungi to mitigate environmental problems are far-reaching, Sonia says. Take an oil spill, for instance.

“You can get bags of straw that have been soaking up, for example, crude oil spills, let them loose with a mushroom that particularly likes crude oil and straw, and then they will actually eat all of that up, break it down, contain any unsafe materials and then just digest it. And then, when you’ve finished, you can simply use them as fertilizer.”

And, she says, there are specific fungi that not only like to eat crude oil and straw, but that also thrive in any given climate.

“There’s a fungi for everything,” she says. “There is literally one or several species that are not only interested in the feedstock you want to get rid of, for example, crude oil, but that will also really enjoy the temperature you’re at.”

Fungi could also be used to clean up landfills or make toilets safer in developing countries.

Sonia says fungi even have potential to alleviate different social problems, like homelessness, by eating extra materials like cardboard to create a more durable material that could be used to build houses.

To stop the structure from breaking down from moisture, she says the material can be covered in latex or Shellac.

“Why aren’t we using mushrooms for everything right now?” I ask.

“Well, they’re just growing,” says Travaglini. “People are just becoming aware of fungi and although it’s all around us — it’s even in our guts, it’s on our skin, it’s in the soil around us. It’s just one of those kind of hidden wonders that people haven’t really tapped into yet.”

“I wonder is mushrooms will eventually just take over the world…” I ask.

“I think one might have an argument that they already have,” Travaglini answers. “They’re so included in everything we do. So they’re really already there, but so far they’re our friends, not our enemies.”

Here’s to staying on good terms with fungi.