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These Jeans Are Made With Fermented Plant-based Ingredients

The first denim garments made with Spiber’s Brewed Protein fibers have sold out in one week. 

Last week Japanese sports apparel brand Goldwin released $950 jeans and a $1,000 denim jacket made with the biotech firm’s fiber alternative to petrochemical or animal-derived raw materials. 

Brewed Protein fibers are made from plant-derived sugars, manufactured using Spiber’s proprietary fermentation process. The process uses microorganisms similar to how ingredients are brewed into alcoholic beverages.

The circular fibers can be broken down at the end-of-use phase into nutrients, and used as feedstock for fermentation and production of new Brewed Protein materials and other products. They can be applied to knit and woven fabrics, fleece, and fur and leather alternatives. 

The men’s cargo jean and jacket are made with 13 oz fabric comprised of 96 percent cotton and 4 percent Brewed Protein fibers. The dark indigo garments are washed with a process that Goldwin says uses 30 percent less water compared to traditional washing. An interior label describes the benefits of Brewed Protein.

The denim pieces are part of “Chance Encounters,” Goldwin’s Spring/Summer 2023 collection which culls inspiration from Japan’s mountainous forests and the “generative and regenerative methodology of foraging.”

The collection is the result of Goldwin’s eight-year partnership to help Spiber scale Brewed Protein. Goldwin’s collection is the first to use Brewed Protein fibers in denim products—a circular-focused category where Spiber sees growth opportunities. 

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“Moving forward, we intend to continue promoting the development, mass production, and adoption of our materials in order to expand product variation and deliver products featuring increasingly higher quantities of our revolutionary fibers,” Spiber said.

Brewed Protein has been adopted by Goldwin for shell jackets and trousers. Last year, The North Face and Pangia dropped hoodies made with the fiber.  

Spiber’s first commercial-scale fermentation plant, located in Thailand, began production in 2022.

Brewed Protein fiber production using polymers produced in the U.S. is scheduled to begin soon, according to the company’s 2020 sustainability impact report.  

Both the Thailand and USA polymer production plants are positioned near agricultural cropland for key feedstocks (sugarcane in Thailand and corn in the U.S.) and will be scaling up in the coming years.