Cultivation of fungi has occurred for thousands of years. Evidence of fermented beverages using yeast dates back to as early as 7000 BCE. In the modern era, fungi are commonly used in the pharmaceutical industry, food and beverage industry, plastics industry, and others. The fashion industry is increasingly seeking methods of making and incorporating sustainable biomaterials. The fashion global market is the world’s second-most polluting industry, behind the oil industry. Given that about 75% of millennials surveyed say they consider sustainability when making a luxury fashion purchase, global luxury brands are unlikely to continue manufacturing goods without environmentally friendly options.

The leather industry in particular stands out as an example of an industry in need of alternatives: increasingly, consumers are looking for natural, non-animal materials to wear. Mycelium is the vegetative component of a fungus and consists of branching, thread-like filamentous structures called hyphae. It is multicellular and can grow in large, complex structures, such as a mushroom. As the hyphae reach a sufficient degree of growth, left to its own devices, the mycelium would traditionally begin to form a mushroom.

However, in a lab setting, rather than permitting the formation of a mushroom, the mycelium is carefully seeded and grown on a substrate in a growth bed. Controlling the bed shape, temperature, carbon dioxide, humidity, air flow, resource availability, and other factors, encourages the mycelium to grow into a desired structure or shape. Within a matter of days, an 18 x 2 x 12-inch sheet weighing several pounds can be grown.

Philip Ross, co-founder of MycoWorks has been using molded mycelium since the 1990s. Since its inception in 2013, MycoWorks has used Ganoderma, a species of mycelium, to grow dense sheets called “Reishi” which can be treated and manufactured like leather. MycoWorks has filed at least ten patent applications in the United States and elsewhere since 2010, with most of those applications still pending.

Bolt Threads offers a similar, mycelium-based leather called “Mylo.” In 2018, Bolt Threads collaborated with Stella McCartney to create a Mylo leather version of McCartney’s Falabella bag. Bolt threads appears to have filed at least two patent applications in the United States and internationally since at least 2018.

A challenge in obtaining mycelium patents is the long-standing prior use and manipulation of various types of mycelium. As humans have been manipulating mycelium materials for decades (and longer), any patent applicant will likely need to make a strong showing their mycelium product is produced by new methods—e.g. some improvement due to a particular nutrient source, temperature, method of layering or seeding the mycelium—or that the material is chemically or microbiologically new in some way. Although such a showing may be costly, given the exponential market demand for alternative “leather” sources, an investment in mycelium “leather” patents may still provide a strong return on investment.