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Chemistry, Materials & Packaging
Mycelium Materials Poised to Leave Conventional Leather Industry Hanging by a Thread

Biotech startups Bolt Threads, Ecovative and Zvnder have discovered how to make the most of mycelium — creating high-quality, sustainable versions of ubiquitous materials such as leather.

Emerging around 5,000 BC, leather has survived the test of time thanks to its durability, comfort and aesthetic appeal. A 2021 assessment undertaken by the Food and Agriculture Organization estimated that roughly 1.4 billion animal hides and skins were used in leather products during the year 2020; whilst another study suggests the leather industry, worth nearly $408 billion in 2021, expects a compound annual growth rate of 6.9 percent between 2022 and 2030.

Global, industrial standards of the material’s production, however, have significant environmental repercussions. Most of the world’s leather is a by-product of the meat industry — which is responsible for the deforestation of vast amounts of land, the emission of greenhouse gases (GHGs), land and water overuse, and the pollution of the same. The US Environmental Protection Agency (EPA) affirms that leather-producing factory farms are responsible for 70 percent of the pollution in national waterways.

The negative consequences of leather manufacturing also extend to human health and wellbeing. In less-developed countries, the tanning industry is rife with human rights abuses. And, whereas leather in a pre-industrialized environment was tanned with plant-based chemicals, most US leather manufacturers use chromium — a known carcinogen.

What are the alternatives?

The alternative leather market has exploded in recent years — first, with mostly petroleum-based materials; but more recently, with innovative, plant- and animal-based alternatives that are markedly better for both people and planet. And a cluster of innovative materials has centered around the humble yet versatile mushroom; or, more precisely, mycelium — the tiny, incredibly strong threads that make up the root network of fungi.

Biotech startups including Bolt Threads, Ecovative and ZVNDER have discovered how to make the most of mycelium — integrating their natural intelligence into the production of familiar materials people have enjoyed throughout history, but with alternative and sustainable origins. The promise of the resulting materials has already yielded widespread recognition, several awards, and industry-leading partnerships and sponsorships.


Image credit: Ecovative

Eban Bayer and Gavin McIntyre co-founded Ecovative in 2007, and quickly made a splash with their mushroom-based wonder material positioned as a sustainable alternative to everything from plastic packaging to building insulation. The New York-based company's latest venture, Forager, is a division focused on designing, marketing and manufacturing vegan, plastic-free, leather-like materials and foams for the fashion and automotive industries that display the same durability, high-tensile strength, density and texture as their animal-derived counterparts. These are produced in AirMycelium™ growth chambers consisting of vertical farms where mycelium is layered and grown on large format sheets. In a few days, vast quantities of animal-free leather and other materials are produced without the need for toxic chemicals or plastic, minimizing the carbon footprint of the final product.

Although Forager hides and foams are not yet available on the market, the product has attracted funding from several investors — including Viking Global Investors — and led to the formation of the Fashion for Good Cooperative with apparel brands Bestseller, PVH, Reformation and Wolverine. Another recent partnership, with the UK-based Magical Mushroom Company, has brought in $60 million in additional financing that is being directed towards the study and discovery of new materials, mycelium strands, and the construction of a larger production facility; as well as the expansion of educational resources regarding mycelium species and the delivery of a high-quality, eco-friendly alternative to leather.

Bolt Threads

Image credit: adidas

Emeryville, CA-based Bolt Threads first gained attention with its fermented Microsilk™, woven from yeast — with which it snagged partnerships with brands including Patagonia and Stella McCartney. The startup has since ventured into mycelium materials, launching its Mylo™ brand of leather in 2018. Also produced through vertical farming, Bolt’s process is powered by 100 percent renewable energy and results in a product that is just as soft and supple as animal leather, but much less hefty on the consumption of natural resources than its conventional, bovine-based counterpart.

Mylo’s ‘UNLEATHER’ initiative has attracted the attention of Stella McCartney, adidas, Lululemon and Kering — now known as the Mylo Consortium — united in their mission to entice the fashion industry away from its reliance on animal- and petroleum-based leathers.

Although Mylo products are also not yet widely available on the market, the enterprise has launched several successful pilot products — including adidas' Stan Smith Mylo™, the first-ever mycelium-based sneaker (April 2021); and Stella McCartney’s Frayme Mylo™ handbag (Summer 2022). Brands including Mercedes Benz, GANNI and Tsuchiya Kaban are also exploring Mylo’s potential.

Given that mycelium-grown leather alternatives are still in small-scale production in comparison to conventional, animal-derived leather, it’s too early to accurately evaluate the material’s environmental footprint. Bolt Threads says it has conducted a preliminary impact assessment that points out significant environmental benefits of Mylo products; but has yet to share the results of an independent life cycle assessment, which it hopes to have available this year. The company also acknowledges that it has not yet achieved its goal of a 100 percent mushroom-based product that matches consumer expectations for softness, strength and suppleness without the help of plastic; Bolt says it will keep pursuing that goal.


Image credit: Zvnder

Meanwhile, Zvnder — a German startup also producing a mycelium-based leather alternative called Fungiskin — claims its product is 100 percent natural, organic and cruelty-free. The business ensures this by keeping production local and small, working with families from nearby Transylvania, where original forests display a high occurrence of tinder sponges (its choice strand of mycelium). This way, the company's experts can ensure that the trees on which the mushrooms grow are cared for and protected over the years. The company strives for zero waste, turning leftovers of Fungiskin into “Fungi-fibers” that can be used when processing paper and nonwovens.

Because of this small-scale production, each piece of Fungiskin is unique in color, shape, thickness and texture. Staying local and small works wonders when it comes to remaining sustainable — the challenges will begin if the company attempts to scale to meet growing consumer demand for durable, sustainable, animal-free alternatives to conventional leather.