To start us off, we have Bolt Threads, who have turned mycelium and spider silk into groundbreaking materials that challenge the norms of traditional textiles. Through advanced science and a deep commitment to sustinability, the company has introduced Mylo and Microsilk.

For billions of years, mycelium, which is the root structure of fungi, has played a vital role in ecosystems, acting as a natural recycler and nutrient provider. Bolt Threads has harnessed this renewable organism to create Mylo, a material that mimics the look and feel of leather whilst minimising environmental harm.

Produced in vertical farming facilities powered entirely by renewable energy, Mylo is grown from mycelium cells on beds of organic, renewable matter. Over time, these cells form a dense, interconnected network, which is then processed, tanned, and dyed into a soft, supple material reminiscent of leather. Not only does this process eliminate the need for animal hides, but it also reduces the carbon footprint associated with traditional leather production.

Currently, Adidas, Kering, lululemon, and Stella McCartney have joined forces with Bolt Threads in a consortium to bring this innovative material to scale.

That’s not it for Bolt Threads, though. They’ve also looked to spiders for inspiration, replicating the properties of their silk to create Microsilk. Renowned for its strength, elasticity, and durability, spider silk offers unparalleled performance, but farming spiders is impractical. Instead, Bolt Threads developed a way to bioengineer silk proteins on a large scale, creating a fabric with remarkable potential.

The process involves introducing silk-producing genes into yeast, which are then fermented with sugar and water. This fermentation yields silk proteins, which are isolated, purified, and spun into fibers. The resulting material is not only strong and lightweight but also environmentally friendly, with the ability to biodegrade at the end of its life.

Microsilk fibres can be spun into yarns and woven into fabrics suitable for garments, offering a sustainable alternative to traditional textiles like rayon and acrylic. By mimicking the natural silk production process, Bolt Threads has created a material that combines cutting-edge technology with ecological responsibility.

A more recent breakthrough, Kelsun, a kelp-based yarn developed by Keel Labs, is turning heads. Unveiled at Stella McCartey’s Summer 2024 runway show last November, Kelsun exemplifies how the ocean’s resources can be harnessed to create eco-friendly materials. With its lightweight texture and luxurious feel, it offers a compelling alternative to traditional fibres like cotton, while boasting a far lower environmental footprint.

Kelsun is derived from seaweed, which is a highly regenerative marine organism. More specifically, the material is made by extracting biopolymers from kelp. These biopolymers are transformed into fine filaments that are stretched, treated, and then spun into yarn suitable for high-end design. Seaweed, in particular, is special in its ability to thrive without land, fresh water, or chemical inputs, whilst simultaneously absorbing carbon dioxide from the ocean. Not only is Kelsun sustainable to produce, but its very source actively contributes to climate mitigation!

Despite its promise, Kelsun is still in its infancy, with commercial viability a few years away. Regardless, it has the potential to revolutionise the fashion industry’s reliance on cotton. Taken from the Stella McCartney article which you can view here, “Using 100% less pesticides and 70x less water, Kelsun™️ makes a valid case for a cotton alternative. Highly compostable, the process taking just 61 days in total, it also improves the health of our ecosystems and leverages seaweed as a raw material.”

Its presence on Stella McCartney’s runway serves a dual purpose: to demonstrate the possibilities of next-generation materials and to challenge the industry to embrace innovation.

The last material we’re covering is Mirum. Created by Natural Fiber Welding, Mirum is redefining leather alternatives with its innovative, plastic-free composition. Crafted entirely from natural sources, using plant-based oils, responsibly sourced natural rubber, minerals, and natural pigments, Mirum stands out as a sustainable material designed to be circular, customisable, and low-carbon. Mirum is entirely free from plastics and petrochemicals, offering an eco-friendly alternative that aligns with the needs of a resource-conscious world. Produced in Illinois, it incorporates virgin natural materials and upcycled agricultural by-products, consciously crafted without the use of fossil fuels or water-intensive processes. This approach not only reduces its carbon footprint but also enhances local biodiversity and regenerates soil systems, making it a material that supports both the environment and the communities involved in its production.

The durability and scalability of Mirum have already attracted leading names in fashion and beyond. Brands such as Ralph Lauren, Allbirds, and Stella McCartney have integrated Mirum into their designs, with applications ranging from luxury accessories to automotive interiors. Backed by significant investment—including $160 million secured by Natural Fiber Welding—and a partnership with Swedish industrial process company IPCO, Mirum’s production capabilities are scaling rapidly. Its adoption is further bolstered by initiatives like Stella McCartney’s SOS Fund, which supports the development of innovative materials that prioritise sustainability and cruelty-free practices.

Together, these innovations demonstrate that the path to sustainable fashion is not only achievable but also exciting, marked by ingenuity and collaboration. As these materials continue to evolve, they pave the way for a fashion industry that balances creativity with responsibility.