Kit Parker, the Tarr Family Professor of Bioengineering and Applied Physics at Harvard’s John A. Paulson School of Engineering and Applied Sciences (SEAS), has led an innovative national research collaborative. This project has opened up a scalable, sustainable avenue for keratin degradation. This creative, up-cycled approach taps into waste from the apparel and meat-processing industries. Each year, these industries produce billions of tons of feathers, wool, and hair. By redesigning and repurposing these otherwise neglected materials, the team hopes to develop highly desirable products that help mitigate serious environmental impacts.
Keratin, one of nature’s strongest and most fibrous proteins, is naturally occurring in hair, skin and nails, offering an intriguing opportunity for upcycling. Both the textile industry and the meat industry generate a lot of waste filled with keratin. This represents a massive potential opportunity for resource recovery. To understand the detailed underlying chemical mechanisms associated with this sustainable process, Parker’s team performed in-depth experimental and molecular simulation studies. Graduate student Yichong Wang and former postdoctoral researcher Junlang Liu were instrumental in these efforts.
Breaking Down Keratin
The study focuses on extracting keratin from lithium bromide solutions. This process produces stiff, malleable gels that quickly release from the solution around them. As these gels are instantaneously solidified upon touching water, it is a prime example of superfast phase transition.
According to Wang, “We wanted to get a better handle on how these processes happen. In the process we found ourselves in a bit of a disconnect between what’s known mechanistically about denaturation and what we were seeing.” The team’s discoveries show that lithium bromide ions interact with water molecules in astonishing fashions. This interaction leads to the water molecules being divided into two separate populations: bulk water and water molecules solvated by the salt counterions.
Liu’s molecular dynamic simulations led to an unexpected and counter-intuitive result. Lithium bromide does not act on proteins, but rather impacts the water that surrounds proteins amis. This knowledge is important for establishing a repeatable, efficient way to extract and reuse keratin products in a reliable manner.
Applications in Tissue Engineering
This research provides a benefit well beyond saving waste from landfills. Keratin has tremendous potential to be used in tissue engineering, another major area of research in Parker’s lab. A more sustainable process of keratin extraction would greatly support research initiatives focused on developing this less harmful alternative.
Keratin’s extraordinary biocompatibility, biodegradability, and non-toxicity make it an excellent candidate for a multitude of biomedical applications. The capacity to regenerate protein sustainably via rapid gel-solid transitions paves the way for creating novel biomaterials. These biomaterials may be applied in biomimetic scaffolding for tissue restoration, offering a template for cell proliferation and restoration.
Sustainable Recycling Process
Their team developed the first-ever closed-loop recycling system for lithium bromide solution, a key ingredient in their sustainable process. This adoption reduces waste and improves the environmental sustainability of keratin extraction.
By making the water less water-like, she said, it lets the protein unwind. He noted that this changed state of water is important for allowing the unfolding of keratin proteins to take place. By creating an environment that encourages protein transformation, the team can harness keratin’s full potential while contributing to sustainable practices.
This research underscores the collaboration between various disciplines, including contributions from Eugene Shakhnovich in the Department of Chemistry and Chemical Biology. Yichong Wang leads the charge as first author of the flagship, expansive study. This underscores how incredibly important graduate students are in the quest to advance scientific knowledge.