As the fashion industry looks beyond synthetics, bio-based materials like Algae Black pigment and kelp yarn Kelsun are reshaping the color and texture of Stella McCartney’s collections.
Algae is having a moment, unfolding as a surprisingly versatile raw material with implications across design, biotechnology, and climate mitigation. The fashion industry, long burdened by its reliance on petroleum-derived synthetics and toxic dyes, is taking notice.
One of the most visible outcomes of this shift is the appearance of Algae Black pigment on Stella McCartney’s runway. The carbon-negative dye, produced by Colorado-based Living Ink, first surfaced in the designer’s Spring 2024 show, printed on the Slippery When Wet t-shirt dress, an archival look from her first collection. It returns in the Summer 2025 collection as part of a broader materials shift, aimed at replacing traditional carbon black with a bio-based alternative. The pigment is made using waste algae biomass, specifically the leftover material from U.S. supplement producers, which would otherwise be destined for landfills. By redirecting this waste and turning it into pigment, Living Ink’s process avoids methane emissions while also locking in atmospheric carbon.
Carbon black — the inky pigment that gives most garments, cosmetics, plastics, and packaging their deepest hues — is traditionally produced by the incomplete combustion of fossil fuels. It’s present in nearly every black-colored item on the market, but it comes with a staggering environmental cost. Producing carbon black releases carbon dioxide and polyaromatic hydrocarbons (PAHs), a class of known carcinogens. Living Ink’s Algae Black, by contrast, sequesters more carbon than it emits, making it a climate-negative product that can slot seamlessly into existing dyeing and manufacturing systems.
What sets Algae Black apart is not just its reduced footprint, but its compatibility. It can be integrated into conventional industrial workflows — whether for screen printing t-shirts or tinting cosmetics — without additional hardware or process overhauls. This is critical for scalability, as many sustainable materials falter under the weight of retrofitting costs. And while black dye may seem mundane, it is one of the most widely used pigments in the world — present in over 90 percent of printed materials and a vast majority of clothing. A shift in this single input could ripple across multiple sectors.
Scott Fulbright, Living Ink’s CEO, has described the pigment as “not going to save the world by itself,” but insists it is “meaningful.” The company recently secured $3 million in funding to expand its reach, including a new production facility and broader algae feedstock sourcing, like brewery waste and fermentation byproducts. This capital injection signals investor confidence in a pigment once dismissed as too niche or too natural to meet industrial performance standards.
“Living Ink is revolutionizing sustainable materials with its groundbreaking algae-based ink technology. Their commitment to innovation and eco-friendly solutions aligns perfectly with our vision for investing in companies that will shape the future,” John Soukas, CEO and co-founder at Norfolk Green Ventures who led the recent funding, said in a statement.
Living Ink isn’t alone in this pursuit. Algae-derived materials are surfacing across the supply chain. Footwear brands like Nike have introduced algae pigments into special-edition sneakers. Fashion conglomerates, including Kering and PVH Corp, have tested algae-based inks in packaging trials. And algae leather, still in early R&D stages, is generating buzz as a potential alternative to plastic-based faux leathers.
Yet color is where algae seems to be making the most traction, perhaps because it offers a literal and symbolic replacement of petroleum in a fashion landscape still heavily reliant on synthetics. And among natural pigments, black has historically been the most difficult to replicate without petroleum. The deepness, permanence, and performance of carbon black are difficult to mimic through plant-based means. Algae, however, offers a workaround: it can be cultivated in bioreactors, grows rapidly with minimal input, and contains high levels of carbon that, when processed, yield an exceptionally dark pigment.
At Stella McCartney, this pigment is not a one-off experiment. The designer has paired the return of Algae Black with another marine innovation: seaweed-based textiles. In her Summer 2024 show, McCartney introduced garments made from Kelsun, a kelp-derived yarn developed by Keel Labs. Spun from biopolymers extracted from seaweed and combined with water and natural additives, Kelsun offers a viable alternative to cotton or synthetic yarns. It uses seventy times less water than cotton, requires zero pesticides, and composts within sixty-one days. Keel Labs has also attracted attention from McCartney’s co-founded SOS Fund, a $200 million investment vehicle for climate innovations.
Like algae, kelp absorbs carbon dioxide while growing, helping mitigate ocean acidification and boosting biodiversity. Unlike traditional crops, it does not require freshwater or arable land. And unlike polyester, it leaves behind no microplastics.
Fashion’s embrace of algae and seaweed comes at a time of mounting pressure. According to the UN, the global fashion industry accounts for up to ten percent of annual greenhouse gas emissions. Dyeing and finishing alone are responsible for around 20 percent of global wastewater. Microplastics from synthetic fabrics now represent up to 35 percent of the plastic that winds up in the oceans. As scrutiny intensifies, designers are turning to biobased solutions.
Still, scaling these solutions remains a challenge. Cost, supply chain complexity, and performance are ongoing hurdles. But seaweed farming is growing rapidly, with the global seaweed market expected to reach more than $16 billion by 2033. Kelp-based yarns like Kelsun are just beginning to make their way into broader commercial production. Meanwhile, algae pigments are gaining legitimacy through partnerships, pilots, and now fashion weeks.
There’s still skepticism in some corners of the industry. Natural dyes often fall short on durability, and early attempts at bioleathers and cellulose fabrics have struggled to meet luxury standards. Yet with brands like Stella McCartney betting on both algae and seaweed in back-to-back seasons, and with infrastructure investments backing it, these materials are no longer peripheral experiments.
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