Of the 4 billion-plus pairs of jeans that are made each year, most are dyed with petroleum-based dyes that use chemicals such as benzene and formaldehyde. At some factories, the toxic wastewater from the process is dumped into local rivers. But at a Bay Area lab, a startup called Huue is experimenting with a less toxic way to turn denim blue: using bio-based dyes brewed in bioreactors.
The original blue jeans—think Gold Rush-era Levi’s—were colored with a dye called indigo that was made from plants. But new synthetic dyes quickly replaced the natural products. “As of about a century ago, when chemical dyes were introduced, because they were so high-performing and so scalable, they basically completely overtook the more renewable plant-based method,” says Michelle Zhu, CEO of Huue. While some denim designers still use plant-based indigo, it’s rare.
The startup, which evolved from cofounder Tammy Hsu’s work in a lab at the University of California-Berkeley, studies the enzymes in plants that create colors in natural dyes, and then replicates them using biotech, beginning with indigo. “We engineer microbes to basically incorporate those enzymes and produce the specific color compound of interest,” Zhu says. Upstairs in the company’s Oakland lab, it runs tests in bioreactors to find the optimal conditions to grow its microbes and create the new dye. Downstairs, it tests the dye on fabric.
The process eliminates the use of petroleum to make dyes. A kilogram of standard indigo dye, the company says, requires 100 kilograms of petroleum to produce. It also eliminates chemicals like the formaldehyde and other chemicals used to make dyes. The resulting dye can be easily used in factories without changing production methods. “It can slot into the existing denim manufacturing process like a one-to-one solution,” says Zhu. “That was really important to us as we were evaluating how we were going to make sure that this was going to have high adoption and be really well received within the industry.”
The startup, which launched a year and a half ago, announced today that it is one of four women-led startups to win $1 million in Melinda Gates’s Female Founders Competition, funded by Gates’s Pivotal Ventures fund, Microsoft’s M12 Fund, and the Mayfield Fund, and it raised another $3 million from a variety of impact investors. Now, it’s beginning to work with denim brands to run pilot tests.
“The industry has also been working to bring in new fibers that are more green and planet-friendly,” says Adriano Goldschmied, the Italian fashion designer known for his denim, who is working with the company as an advisor. “But the real problem and the most important one is: How do we sustainably produce indigo? When I first met Michelle and she presented Huue’s technology, I immediately realized that she had the solution to change our industry.” The startup also aims to have a wider impact on the world of apparel, using biotech to create new dyes across the color spectrum and “reinvent the color industry,” Zhu says. “We have our sights set on the broader $33 billion dye market.”
Correction: We’ve updated this article to correct the size of the dye market and to note that the bacteria do not excrete the dye.