Researchers have developed a sustainable method to extract 22-karat gold from old motherboards using a food industry byproduct.

The byproduct used is whey protein, which is transformed into a matrix of protein amyloid fibrils to adsorb gold ions from e-waste. The process involves denaturing whey proteins under acidic conditions and high temperatures to form a gel, which is then dried into a sponge.

The protein fibril sponge selectively absorbs gold over other metals when placed in a dissolved metal ion solution from electronic parts. The cost of recovering gold using this method is 50 times lower than the value of the gold recovered, demonstrating both commercial and environmental benefits.