This article has been commissioned by the sponsor and produced by the Science/AAAS Custom Publishing Office.
As climate change spurs a global reckoning, scientists and entrepreneurs are turning to nature's own toolkit to dismantle centuries of industrial waste and build a more resilient, sustainable economy.
Walk into almost any clothing store and you'll find racks of jeans marketed as sustainable -- some boast organic cotton, others tout water savings, and many carry vague labels like "eco-friendly." Yet behind these campaigns, the story is more complicated.
Denim's iconic indigo hue has a dark history: a chemical-intensive process that begins with petrochemicals and ends in rivers running blue with industrial waste. Few objects capture the contradictions of modern industry better. Jeans symbolize casual style and conscious consumption, but they also embody the false comfort of greenwashed solutions. And denim is not alone.
Misleading claims about recyclability, unclear environmental pledges, and false carbon neutrality statements have all been called out as greenwashing. Even seemingly straightforward green solutions can have tradeoffs. Electric vehicles, for example, can reduce carbon emissions but depend on mined metals with significant social and environmental costs. The path to true sustainability is riddled with complexities that simple labels obscure -- and tackling them requires not only scientific breakthroughs but also the persistence to enact change within resistant industries.
That's why organizations like the BioInnovation Institute (BII) are backing startups willing to confront these entrenched challenges. A new wave of deep-tech innovators is moving beyond superficial fixes, offering change at the molecular level.
Detoxifying denim
For more than a century, denim dyeing has changed little. The process still relies on synthetic indigo, a water-insoluble pigment that must be converted into a soluble form, leucoindigo, using a reducing agent such as sodium dithionite. Cotton yarn is dipped into this bath, turning yellowish at first, then blue as the dye oxidizes during drying. The cycle is repeated for deeper shades before rinsing to remove excess dye.
This reaction produces toxic byproducts, including aniline, a known carcinogen. "The wastewater from this process is quite full of hazardous chemicals, and it's also super corrosive," explains Ditte Hededam Welner, biochemist and co-CEO of Nordic Blue. This runoff pollutes waterways and damages farmland, affecting local livelihoods. The health of workers in dyeing mills -- predominantly women -- is also at risk, as they are exposed to open vats of harsh chemicals with little protection. Dyeing is immensely resource-intensive; producing a single pair of jeans can require dozens of liters of water laden with chemicals.
Instead of overpowering nature with chemistry, Welner and her team at Nordic Blue are developing a biological alternative. Nordic Blue is a participant in both BII's Venture Lab and Venture House programs, which help early-stage innovators navigate technical and commercial hurdles. The company's process replaces synthetic indigo with indican, a water-soluble indigo precursor found naturally in Indigofera plants, legumes that thrive in tropical and subtropical climates. In nature, plants use indican -- a sugar molecule attached to an indigo precursor -- as a safe way to store indigo, Welner explains.
Nordic Blue has developed a biocatalytic process that mimics this natural machinery. White cotton yarn is dipped in a bath of colorless indican. Then, an enzyme called β-glucosidase is added, snipping the sugar molecule off the indican. This reaction releases the indigo precursor, which spontaneously oxidizes in air to form the deep blue pigment directly on and within the cotton fibers. The process eliminates the need for harsh reducing agents and avoids toxic byproducts.
Using enzymes brings precision and efficiency. As biological catalysts, enzymes perform specific tasks under mild conditions -- neutral pH and room temperature -- without the energy inputs or harsh environments typical of industrial reactions. This specificity prevents unwanted byproducts.
One major challenge is speed. "We need to be able to develop the color within a minute," Welner says. The process must match the pace of the large, continuous-feed dyeing machines used by the industry. Achieving this requires optimizing the enzyme's efficiency and reaction conditions. Nordic Blue has also chose to design a "drop in" solution compatible with existing dyeing mills.
Beyond the environmental benefits, Welner emphasizes the social impact. "If there is nothing dangerous in those baths, it's going to be better for the workers," she says. "And on a larger scale, if there are no harsh chemicals, there will be fewer residues in the final product -- maybe even a benefit for the end consumer."
Mining microbes
A similar bio-based approach is addressing another sustainability challenge: the recycling of electric vehicle batteries. By 2040, the world will need to recycle more than 20 megatons of used car batteries, a twentyfold increase from today. "Sustainably doing that is going to be super important for the industry," says Odd Hansen, co-founder of MicroMiner, another participant in BII's Venture Lab program.
Batteries are a mix of valuable metals, graphite, and other materials -- requiring complex separation. Current recycling methods include hydrometallurgy, which uses large quantities of strong acids to leach metals from old batteries, generating hazardous waste.
MicroMiner's solution replaces this chemical-heavy process with a targeted biological one, based on biosorption. The company's technology originated from the work of co-founder Celia Méndez García, who studied biological materials capable of binding metals with remarkable efficiency. "We observed that these absorbents in nature accumulate enormous amounts of metal," Hansen says. These biological materials act like molecular sponges, capturing specific metal ions through chemical groups on their surfaces that bind strongly to metals. MicroMiner's innovation lies in replicating and improving this property in the lab.
The team uses engineered microbes to produce tailored versions of these natural absorbents, turning microbes into miniature factories. By identifying and expressing the genetic sequences responsible for metal binding, they can generate pure, efficient biosorbents designed for specific metals.
This bio-manufacturing process allows MicroMiner to create a distinct absorbent for each valuable element. A liquid containing dissolved battery metals flows through a cascade of filters, each designed to capture one target metal -- cobalt in one stage, nickel in another, lithium in a third, and so on, Hansen explains.
This precision replaces the complex solvent extraction phase with a clean, biological filtration system. "We could reduce chemical use by more than 70%," Hansen says. Early results are promising: "On lithium, we are beating all other references for how much we can extract."
MicroMiner combines in-house R&D with a network of European university collaborations and is now building a customer pipeline to move its technology from the lab into industrial pilots, aiming for commercial viability by 2028 or 2029.
The case for deep science
The need for deep-tech solutions is growing as the limits of superficial "green" marketing become clear. "You can't just fall into a greenwashing trap by saying, 'This is new and better,'" says Christian Brix Tillegreen, director of planetary health at BII. "You might have a specific ingredient that is sustainable, but you haven't changed the systemic issue of the actual industry. Consumers are slowly seeing through that."
The path to genuine systemic change is far harder than crafting a marketing campaign, Tilgreen adds. It requires solving challenges of scale, navigating global regulations, and managing market risk. "This kind of stuff doesn't go fast," Hansen agrees.
BII's approach is to nurture innovations that offer real, structural change. The motivation comes directly from the front lines of environmental challenges. Supporting these ventures, Tillegreen explains, demands a different mindset than in traditional life sciences like healthcare, where milestones are well-defined. "You have very clear data points and very clear inflection points of clinical trials, preclinical trials, phase one, two, and three," he says. In planetary health, "we deal with a broader risk."
Market risk is often greater than technical risk, depending on consumer and industry adoption. BII's role, Tillegreen says, is to act as a bridge between academia, startups, and investors -- a "melting pot" that connects what's scientifically possible with what can be financed and scaled.
For founders like Hansen and Welner, this ecosystem is crucial. Entering the Venture Lab and Venture House programs has been, as Welner puts it, "a major kick in the ass. It's that 'get going now' kind of feeling."
From green to resilient
According to Tillegreen, the conversation around sustainability is shifting. It's not just about being green anymore, he says. "It's about resilience, sovereignty, and stabilizing supply chains." The priority has moved from simply greening industries to securing them against disruption.
By replacing fragile, centralized supply chains with distributed, biological solutions, companies like Nordic Blue and MicroMiner are not just cleaning up their sectors -- they're helping build a more stable global economy. "Every time we open up an application, we get a little bit climate depressed," Tillegreen admits, "because these scientists have really understood the problem they're solving. We are burning on many, many fronts. But I am a strong believer that if we build technology correctly with the right founders, we can gradually start migrating towards biological solutions. That's the only way we can survive."