Researchers at ETH Zurich have designed a sustainable method to extract gold from electronic waste using a byproduct of cheese production. Electronic devices, from smartphones to laptops, contain small amounts of gold due to its excellent conductivity and resistance to corrosion. With the rapid turnover of electronic gadgets, e-waste has become the fastest-growing waste stream globally, reaching 62 million tonnes in 2022, and only 22.3 percent of this was formally collected and recycled, leaving vast amounts of valuable materials unused. Professor Raffaele Mezzenga and scientist Mohammad Peydayesh led the ETH Zurich team in developing a method that utilizes "whey", the liquid byproduct of cheese-making. By processing whey proteins into amyloid fibrils, they created a sponge-like aerogel capable of selectively absorbing gold ions from acidic solutions derived from e-waste. Professor Mezzenga stated, The fact I love the most is that we're using a food industry byproduct to obtain gold from electronic waste. You can't get much more sustainable than that!" In laboratory tests, this aerogel successfully extracted gold from dissolved computer motherboards. The sponge drew out gold that was about 90.8 percent pure, yielding a 22-carat nugget weighing approximately 450 milligrams. The research team is also exploring the use of other food industry byproducts, like pea protein and fish collagen, to diversify the sources of the aerogel. The process is economically viable, with operational costs significantly lower than the market value of the recovered gold, unlike traditional gold extraction techniques that rely on toxic chemicals like cyanide.