Harvard’s salt trick could turn billions of tons of hair into eco-friendly materials– www.sciencedaily.com The textile and meat-processing industries produce billions of tons of waste annually in the form of feathers, wool and hair, all of which are rich in keratin – the strong, fibrous protein found in hair, skin and nails. Turning all that animal waste into useful products – from wound dressings to eco-friendly textiles to health extracts – would be a boon for the environment and for new, sustainable industries. But upcycling proteins is challenging: Breaking down, or de-naturing, proteins into their component parts typically requires corrosive chemicals in large, polluting facilities, keeping any cost-effective protocol out of reach. Researchers in the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have uncovered key fundamental chemistry of how proteins like keratin de-nature in the presence of certain salt compounds – an insight that could take protein recycling to the next level. A team led by Kit Parker, the Tarr Family Professor of Bioengineering and Applied Physics at SEAS, combined experiments and molecular simulations to better illuminate the chemical mechanisms by which salts cause proteins to unfold. They’ve shown that a solution of concentrated lithium bromide, a salt compound known to break apart keratin, interacts with the protein molecules in a completely unexpected way – not by binding to the proteins directly, as was conventional wisdom, but by changing the structure of the surrounding water molecules to create a setting more favorable for spontaneous protein unfolding. This insight allowed the researchers to design a gentler, more sustainable keratin extraction process, separating the protein out of solution easily and without the need for harsh chemicals. The process can also be reversed with the same salt mixture, enabling recovery and reuse of lithium bromide denaturants.
