Mylo

Mylo was a new biomaterial technology and product line for Bolt Threads: a leather alternative grown from mycelium, distinct from the recombinant silk platform that produced Microsilk and b-silk. Fungal hyphae were fed sawdust and other organic substrate inside humidity- and temperature-controlled growth rooms, where they wove themselves into a foamy mat. The mats were harvested, tanned, finished, and assembled into commercial-grade hides with the look, hand-feel, and structure of animal leather. Vegan, biobased, and engineered for the fashion and sportswear supply chains that already knew how to work with leather.

In 2020, Bolt formed the Mylo Consortium with Adidas, Kering, Lululemon, and Stella McCartney. At the time, this was the largest joint development agreement aimed at bringing a biomaterial to the mass market. Each brand committed seven-figure sums for exclusive access and co-development. Stella McCartney's Frayme Mylo, the first mushroom leather handbag to appear on a Paris Fashion Week runway, debuted in October 2021 and went on sale in summer 2022 as a numbered limited edition. Lululemon released Mylo-handled yoga bags in 2022, and Adidas previewed a Stan Smith Mylo sneaker.

Reaching commercial scale meant solving substrate biology, tunable hand-feel and aesthetics, finishing chemistry, manufacturing partners, brand co-development, and the full regulatory and supply chain stack for a category that did not yet exist. Mylo proved that a fungal material could move from petri dish to brand-name product in a few years.