There are traditionally two ways to make a leather jacket. One involves a cow and takes years. Another involves synthetic fabric and requires plastic. But there is a third option: thick sheets of woven sponge grown over a few weeks on everything from sawdust to agricultural waste.
“It feels a little and still smells like mushrooms, but it looks like a piece of old leather jacket,” said Alexander Bismarck, a materials researcher at the University of Vienna.
Over the past decade, companies in the United States, Indonesia and Korea have proclaimed mushroom leather as an ethically and environmentally sustainable substitute for both cowhide and plastic. Previously, there was not much research to support their claims. But a study published by Dr. Bismarck and his colleagues last week in Nature Sustainability, find that sponge leather stacks well together when it comes to versatility and sustainability.
Beginning in the 1950s, inventors began filing patents based on sponge mats as a material for paper, wound dressings, and a variety of other products, but they never quite caught on, said Mitchell Jones, lead author and materials researcher at Vienna University of Technology.
But in the last decade, companies like MycoWorks and Bolt Threads have started manufacturing and selling sponge leather products.
“With leather, you are limited to the skin that an animal produces during its lifetime, while mycelial mats can be grown to specifications, ”said Sophia Wang, co-founder of MycoWorks.
Dr. Bismarck said the potential for custom materials is enormous because different kinds of fungi have different properties, such as toughness, water resistance, and there are potentially millions of species to choose from.
Sponge leather is also potentially more sustainable than other leather sources. The tanning process is energy intensive and produces a lot of sludge waste – and the production of synthetic leather requires plastic, which involves oil. “You get a biological organism to produce all your production for you, so there is no real energy need,” said Dr. Jones.
“It does not require light. And once you get this material, you can treat it after quite simple chemical treatments compared to what you would normally do for leather tanning. ”
But while mushroom leather did quite well in the team’s durability test, there are still some questions about its long-term toughness.
“The first industry results indicate that the durability is quite good compared to animal leather,” said Dr. Jones, “but some in the industry cheat a little because they incorporate a felted polyester and turn it into a composite leather.”
The sponge leather industry is still in its infancy and largely produces concept evidence for the luxury market: prototypes of Bolt Threads sponge leather handbag sold for around $ 400 when they were available, a price equivalent to a good quality leather bag.
But Dr. Jones believes costs are likely to fall as the industry grows. “There are already massive mushroom growing industries that produce all kinds of mushrooms for the culinary market. The technology for mass production of mushrooms is already there. ”
Fungus leather products can soon appear everywhere, like fungi after rain. The question is whether consumers will feel the magic. After all, if you regret the mushroom leather pants you buy in the future, can you just throw them out in the garden and let them become compost?
“It’s all not yet investigated,” said Dr. Bismarck.