A bag for the future; will fungi be the new leather?

By Agnes van den Ende

In Utrecht you’ll come across leather bags anytime. However, it is not the most sustainable option when it comes to materials. Lately, fungal mycelium has come into sight as a nice, bio-based alternative. This is exactly what PhD student Jeroen van den Brandhof is working on: how to grow leather from a fungus.

In his research he works with pure mycelium materials. Mycelium is the root network of fungi, which can be used as a renewable biomaterial. Jeroen turns the mycelium into films with leather-like properties. After a week of growth in nutrient-rich shaking cultures, the mycelium is blended, filtered and dried.

“Actually, it feels more like paper at first touch, but with treatment you could move more towards leather-like materials.” Jeroen explains how he uses plasticizers to create a more elastic material. By creating internal connections, the film can be made stronger. An alarm goes off as Jeroen says: “One second, I will just take this out…” As he is fishing out his samples from a wet plate, he explains how he is testing the moisture absorption of the material. Every aspect of the film has to be tested to create an attractive product.

But why is mycelium leather so promising? The idea is simple yet powerful: using fungal growth instead of animals. “If you look at it,” Jeroen says, “you have to raise a cow for years to ultimately have leather. It takes less time to generate fungal biomass.” Fungi don’t need land or years to grow. He also adds that cows have a limited surface area, while mycelium can keep on growing. That makes the materials both scalable and sustainable. 

“In the end, it is about sustainability,” Jeroen says. “We are creating a natural system which can be easily degraded again.” By researching how to recycle mycelium materials, Jeroen tries to make the materials even more sustainable. This also makes mycelium stand out from many other leather alternatives.

Jeroen does not design products from his research himself, but he hopes that his research will come to good use. There are many companies already experimenting with mycelium leather. So, even though we might still have to wait a little, the mycelium bag of the future might just be around the corner.