A brand new sustainable technique has been developed to interrupt down keratins, remodeling leftover wool and feathers into helpful merchandise.
Yearly, textile and meat-processing operations generate billions of tons of feathers, wool, and hair. These supplies are wealthy in keratin, the powerful, fibrous protein present in hair, pores and skin, and nails.
Changing this animal waste into helpful items, from wound dressings and eco-friendly textiles to well being extracts, may benefit the surroundings and assist construct new sustainable industries. The bottleneck is protein upcycling: breaking proteins into their elements often depends on corrosive chemical compounds utilized in massive, polluting services, which retains an reasonably priced course of out of attain.
Researchers on the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have recognized elementary chemistry that explains how proteins resembling keratin de-nature within the presence of sure salt compounds. This perception may transfer protein recycling ahead in a significant method.
A staff led by Package Parker, the Tarr Household Professor of Bioengineering and Utilized Physics at SEAS, mixed laboratory experiments with molecular simulations to make clear how salts set off protein unfolding. They discovered that concentrated lithium bromide, a salt recognized to interrupt aside keratin, acts in a stunning method. Moderately than binding on to the proteins, as typical knowledge steered, it alters the construction of close by water molecules, creating circumstances that favor spontaneous unfolding.
This perception allowed the researchers to design a gentler, extra sustainable keratin extraction course of, separating the protein out of resolution simply and with out the necessity for harsh chemical compounds. The method will also be reversed with the identical salt combination, enabling restoration and reuse of lithium bromide denaturants.
The analysis is printed in Nature Communications and is also featured in a Behind the Paper blog post.
Inspired by keratin biomaterials
First author Yichong Wang, a graduate student in chemistry who works in Parker’s group, said the research builds on the lab’s longstanding interest in developing keratin biomaterials with shape memory for biomedical applications. They had previously observed that keratin extracted from lithium bromide solvents can form thick, shapeable gels that readily separate from the surrounding solution and solidify almost immediately when placed back in water. While useful, they found the behavior odd, and they wanted to understand it better.
“We thought there might be a gap between current mechanistic understanding of how de-naturation works, and what we were seeing,” Wang said. “That’s when we got very interested in the mechanism itself to see if we could optimize our extraction procedures by explaining this phenomenon better.”
Molecular dynamics reveals shifts in surrounding water
To dig deeper, the team turned to the lab of Professor Eugene Shakhnovich in the Department of Chemistry and Chemical Biology, whose expertise is in protein biophysics. Molecular dynamics simulations led by co-author Junlang Liu allowed them to see that the lithium bromides were not working on the proteins at all, but rather, on the water around them.
It turns out lithium bromide ions cause water molecules to shift into two different populations – normal water, and water molecules that become trapped by the salt ions. As the normal water volume decreases, the proteins start to unfold due to the thermodynamic shift in the environment, rather than being directly ripped apart like in other de-naturation methods. “Making the water less like water, allows the protein to unfold itself,” Wang said. They had similar results by testing simpler proteins like fibronectin, pointing to a universal mechanism.
Better understanding and designing protein extraction methods that are less energy-intensive and less polluting than conventional ones opens potential avenues for protein-upcycling industries. In the Parker lab, using keratin as a substrate for tissue engineering is a major research thrust; having a reliable, sustainable method to extract and re-use such products would bolster their efforts.
What’s more, the process could lay a path for a whole new biomaterials industry, turning a massive waste stream like hair or chicken feathers into low-cost recycled materials, possibly as an alternative for traditional plastics, for example.
Reference: “Entropy-driven denaturation enables sustainable protein regeneration through rapid gel-solid transition” by Yichong Wang, Junlang Liu, Michael M. Peters, Ryoma Ishii, Dianzhuo Wang, Sourav Chowdhury, Kevin Kit Parker and Eugene I. Shakhnovich, 26 July 2025, Nature Communications.
DOI: 10.1038/s41467-025-61959-9
The research had many sources of federal support, including the National Institutes of Health (R35GM139571 and R01EY030444) and the National Science Foundation through the Harvard University Materials Research Science and Engineering Center (DMR-2011764). Other funding came from the Health@InnoHK program of the Innovation and Technology Commission, part of the Hong Kong SAR Government; and the Medical and Health Informatics Laboratories at NTT Research, Inc.
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