Thirty years from now, we might remember cotton as we remember asbestos today: it worked, but the hidden cost was unsustainable. The exhausted yeast from fermentation (beer, wine, drugs) could be the answer. The Penn State study just posted on Proceedings of the National Academy of Sciences documents the first pilot production on an industrial scale: 450 kilos of natural fibers In Germany, costs under 6 dollars per kilo, performance superior to wool, almost zero environmental impact.
Professor Melik Demirel compare this shift to the domestication of sheep 11.000 years ago. Only this time we tame the yeast. And let's free up millions of hectares of land that today produce cotton while 733 million people suffer from food insecurity.
Yeast that becomes fiber
Yeast biomass left over from alcohol and drug production is composed of proteins, lipids, and sugars. It usually ends up in the garbage: Demirel and his team transformed it into natural fibers using a process developed years earlier. How? They extract the proteins as aggregates (imitating the naturally occurring amyloid structures), dissolve them in a solution, and push them through a device called a spinneret, which produces continuous filaments. The fibers are washed, dried, and spun into textile yarn.
The key lies in the solvent used to dissolve the proteins: the same one used to produce lyocell, the fiber derived from wood cellulose. It is 99,6% recoverable. This means the process leaves no chemical waste and can be repeated cycle after cycle without waste.
Natural fibers, the numbers that count
The team produced over 450 kilograms of fiber in a German factory, with continuous production lasting more than 100 hours. The data collected was used for a life cycle analysis that calculated costs, water consumption, production output, and greenhouse gas emissions at each stage. The results overturn the very idea of textile sustainability.
Commercial production of this fiber could compete with wool and other natural fibers On an industrial scale, but with drastically fewer resources. The estimated cost is $6 or less per kilogram (about 2,2 pounds), compared to $10–12 for wool. It uses less water and less land, even considering the land needed to grow the grains used in the fermentation processes that produce the yeast. And greenhouse gas emissions? Almost zero.
As Demirel explains:
"Just as hunter-gatherers domesticated sheep for wool 11.000 years ago, we are domesticating yeast for a fiber that could shift the agricultural focus toward food crops. We've demonstrated that this material can be produced economically, with less water and land, yet performs better than any other natural or processed fiber, while almost completely eliminating emissions. The saved resources could be applied elsewhere, such as converting land to grow food."
Land taken away from food
Cotton occupies approximately 35 million hectares of arable land worldwide. Nearly 40% of that area is in India, a country classified as “serious” in Global Hunger Index. To produce a T-shirt and a pair of jeans, up to 2.642 liters of water are needed. Raw cotton is cheap, but the environmental impact is devastating.
Demirel asks a simple question: what would happen if that land, water, resources, and energy were used to grow food instead of fiber? The analysis shows that biomanufactured natural fibers require less land, water, and other resources. Clearing even a portion of those 35 million hectares could have a significant impact on global food production.
Fast fashion, slow consequences
Current production methods not only consume significant resources, but generate enormous waste. In the US, more than 66% of clothing produced annually ends up in landfills.
Natural yeast fibres are biodegradable: they decompose without leaving any residue. microplastics nor toxic residues. Unlike polyester, which can take 200 years to degrade.
Biofabrication allows for the production of sustainable, high-performance fibers that don't compete with food crops for land, water, or nutrients. As Demirel emphasizes:
“Adopting biomanufactured protein fibers would mark significant progress toward a future where fiber needs are met without compromising the planet’s ability to feed its growing population.”
Natural fibers, from pilot project to market
In Demirel's laboratory at Penn State, they have demonstrated that the fiber can be made. In the pilot production in Germany, together with Tandem Repeat Technologies (the spin-off founded by Demirel) and to Thüringisches Institut für Textil- und Kunststoff-Forschung, they've proven it can compete in the global fiber market. The next step? Bringing it to mass scale.
The resources saved could make the difference between clothing and food. Or maybe, for the first time, both without having to choose.
