Mycelium, Brewed Protein, and the Next Fiber

A small group of companies is trying to produce commercially viable biological materials. MycoWorks grows leather-like sheets from mycelium, the root network of fungi; in March 2021 it and Hermès announced the Victoria travel bag made with its 'Sylvania' material. Bolt Threads developed a mycelium material called Mylo with backing from Stella McCartney, Adidas, Lululemon, and Kering, but paused production in 2023 after failing to secure funding—a reminder of how hard it is to scale. Spiber, a Japanese company, ferments 'Brewed Protein' fibers from microbes, and firms such as Modern Meadow work with engineered and plant-based proteins. The materials remain expensive and produced in small volumes. Still, the direction is notable: for the first time since the synthetic fibers of the mid-twentieth century, a fundamentally new class of textile material is being tested by major brands, and some of it is grown rather than refined from petroleum.