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Biobased Chemicals

Archroma and Stony Creek to scale up plant-based indigo dye

Deal will move natural product from at-home kits and niche markets to industrial denim production

by Craig Bettenhausen
April 25, 2022

Rows of a round-leaved plant.
Credit: Stony Creek Colors
Indigo dye can be extracted from indigofera bushes, but most indigo today is made via chemical synthesis.

The natural dyestuff maker Stony Creek Colors is expanding its pact with the dye and pigment maker Archroma to bring plant-based indigo dye to industrial scale. Archroma will implement Stony Creek’s natural indigo process at its facility in Salvatierra, Mexico, and test the resulting dye with its customers in the denim industry.

Indigo dye was originally derived from indigofera bushes, which is how Stony Creek makes it now. The synthetic route to indigo emerged in the late 1800s and was an early pillar on which firms like BASF built their businesses. The process is cheap and efficient, but it requires harsh chemicals such as cyanide and formaldehyde.

Today, the plant-derived product makes up less than 1% of the 50,000 to 70,000 metric tons (t) of indigo the textile industry uses each year, according to Matilde della Fontana, an associate at the market research firm Lux Research.

Stony Creek CEO Sarah Bellos says the firm has been working for 5 years on every step of indigo production—from breeding indigofera strains that give a higher yield of dye to redesigning extraction methods—to “bring the process for growing and producing natural indigo into the 21st century.” Archroma has been engaged at the lab and pilot scale for 2 years, Bellos says, and she expects the partners will produce enough indigo for more than 60 million pairs of jeans per year by 2027.

Archroma’s size and connections to mass-market denim producers is a big win for Stony Creek, della Fontana says. “The significance of this deal is that a company like Archroma has the means to produce major quantities of this indigo,” she says. “It’s a good deal, especially for Stony Creek Colors.”

Archroma is owned by SK Capital Partners, which formed the company from a Clariant textile chemical business it bought in 2013. Archroma later acquired the dye maker M. Dohmen and dye and textile chemical assets from BASF.

Being biobased does not always make a product better for the environment, della Fontana cautions. Several start-ups are working on methods to make dyes and pigments using plants, microbes, enzymes, and algae, but “synthetic dye and traditional dyeing are very efficient processes that have been around for a really long time,” she says. “In terms of energy use, as an example, they’re way more efficient.” Because the scales of the natural routes are so small, “we don’t know yet if they’re really more sustainable.”

Bellos agrees. “A product can be biobased but still not be climate positive,” she says. But Stony Creek’s plant-based process is both, she claims, capturing 10 times as much carbon dioxide as synthetic indigo production releases.



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