Innovative Protein Fibres Offer Low-Cost, Eco-Friendly Alternative to Cotton and Wool

Professor Melik Demirel, the Pearce Professor of Engineering and Huck Chair in Biomimetic Materials at Pennsylvania State University, is leading a research effort that could change how the world thinks about both food and fabric. His team has developed a new type of high-performance fibre made from the leftover yeast produced in fermentation processes such as brewing beer, making wine, or manufacturing pharmaceuticals. The process takes what was once considered industrial waste and turns it into a biodegradable fibre that could reduce the environmental impact of textile production while helping to free agricultural land for food cultivation.

Allen, B. D., Ghotra, B., Kosan, B., Köhler, P., Krieg, M., Kindler, C., Sturm, M., & Demirel, M. C. (2025). Impact of biomanufacturing protein fibers on achieving sustainable development. Proceedings of the National Academy of Sciences, 122(45). https://doi.org/10.1073/pnas.2508931122

The study describes how Demirel’s group repurposed yeast biomass; rich in proteins, lipids, and sugars; into a material strong enough to compete with wool and other natural fibres. What makes this particularly significant is that it requires far less land and water to produce, offering a promising alternative to fibre crops such as cotton that demand large areas of farmland and intensive irrigation.

The inspiration for this innovation comes from Demirel’s long-standing research into protein-based materials. For more than a decade, his laboratory at Penn State has explored how naturally occurring protein structures can be used to create durable, sustainable fibres. In this project, the researchers identified yeast biomass as a valuable resource that had previously gone unused on an industrial scale.

Professor Melik Demirel, the Pearce Professor of Engineering and Huck Chair in Biomimetic Materials at Pennsylvania State University stated,

“In my lab at Penn State, we demonstrated we could physically make the fiber. In this pilot production at the factory, together with Tandem and TITK, we demonstrated we could make the fiber a contender in the global fiber market. Sonachic, an online brand formed by Tandem Repeat, makes this a reality. Next, we will bring it to mass market.”

The process begins by collecting the leftover yeast produced during fermentation. This biomass, which is typically discarded, contains abundant proteins that can be isolated and processed. The team developed a method to extract protein aggregates from the yeast, dissolve them in a solvent similar to the one used to make Lyocell fibres, and then pass the mixture through a spinneret; a device with tiny openings that spin the solution into continuous strands. Once the fibres are formed, they are washed, dried, and spun into yarn suitable for weaving into fabrics.

These fibres are not only strong but also biodegradable, meaning they can naturally break down after disposal. This characteristic makes them a viable replacement for synthetic materials like polyester, which contribute significantly to long-term environmental pollution. Another key advantage of this process is its efficiency: the solvent used in production can be recovered and reused at a rate of 99.6%, dramatically reducing waste and cost.

To test the method beyond the lab, Demirel’s team partnered with the Thüringisches Institut für Textil- und Kunststoff-Forschung (TITK) in Germany and the spin-off company Tandem Repeat Technologies. Together, they achieved pilot-scale production of more than 1,000 pounds of fibre in both continuous and batch operations, each lasting over 100 hours. The success of this pilot proved that the process could be scaled beyond laboratory conditions.

The team also conducted a detailed lifecycle assessment, evaluating the environmental and economic aspects of the fibre from raw material sourcing to end-of-life disposal. This analysis measured factors such as cost, water use, energy consumption, and greenhouse gas emissions. The results showed that the fermentation-based fibre could be produced for approximately six dollars per kilogram; roughly half the cost of wool; and with a significantly smaller environmental footprint.

Beyond its technological promise, the research points toward a broader societal impact. Traditional fibre crops such as cotton occupy vast tracts of farmland and consume large volumes of water. Globally, around 88 million acres of land are used to grow cotton, with nearly 40% of this located in India; a country that continues to face serious food security challenges. Producing just a single T-shirt and pair of jeans from cotton can require over 2,600 gallons of water.

Demirel’s team argues that by replacing fibre crops with fermentation-derived fibres, some of that land and water could instead be redirected toward food production. This shift could help address global hunger while reducing the textile industry’s environmental toll. According to the United Nations, more than 733 million people around the world faced food insecurity in 2024. Repurposing even a portion of agricultural land currently devoted to fibre crops could therefore make a measurable difference.

The study also highlights how much textile waste contributes to the problem. In the United States, more than two-thirds of clothing produced each year ends up in landfills. The new biodegradable fibre offers a pathway to reduce that waste while aligning with circular economy principles.

The concept of protein-based fibres is not entirely new. In the 1930s, materials like Lanital; derived from milk proteins—were briefly popular before being replaced by cheaper and stronger synthetic fibres such as polyester. What sets this new yeast-based material apart is its improved performance, lower cost, and sustainable production process.

Demirel describes the approach as “domesticating yeast for fibre,” drawing a historical parallel to how early humans domesticated sheep for wool roughly 11,000 years ago. Just as that innovation transformed early economies and societies, this new biotechnology could reshape modern material production by redirecting agricultural focus toward food crops while using industrial byproducts for textiles.

The research team plans to refine the process further and explore commercial applications. Their next steps include improving the fibre’s performance characteristics, developing more efficient solvent recovery systems, and integrating the technology into large-scale manufacturing. The team’s spin-off company, Tandem Repeat Technologies, is already working on bringing the material to market through an online brand called Sonachic.

The potential implications extend far beyond fashion. Fermentation-based fibres could be used in technical fabrics, industrial textiles, or even medical materials, reducing dependency on petrochemicals and natural fibre crops alike. With nearly all clothing still relying on fibres that either deplete natural resources or contribute to pollution, innovations like this could form part of a more sustainable textile ecosystem.

This work demonstrates how cross-disciplinary engineering can bridge environmental and humanitarian goals. By transforming waste from one industry into valuable input for another, the process reduces pressure on ecosystems while potentially contributing to global food security. The idea aligns closely with the United Nations Sustainable Development Goals, particularly those concerning responsible production, climate action, and zero hunger.

While many challenges remain before fermentation-based fibres become mainstream; including large-scale integration, cost stability, and consumer acceptance; the progress made at Penn State represents a significant step toward a more sustainable materials future. As Professor Demirel and his collaborators continue refining their process, their work serves as a reminder that some of the most impactful engineering solutions arise not from new resources, but from finding new value in what the world leaves behind.