Cleaner water, with an assist from beer

Every year, beer breweries discard thousands of tons of surplus yeast. Researchers from MIT and Georgia Tech came up with a use for it: clearing lead from contaminated water.

Through a process called biosorption, yeast can quickly absorb even trace amounts of heavy metals. The researchers had previously calculated that yeast discarded from a single brewery in Boston would be enough to treat the city’s entire water supply.

Now they’ve shown they can package that yeast inside hydrogel capsules that can be easily removed from the water. The capsules are “porous enough to let water come in, interact with yeast as if they were freely moving in water, and then come out clean,” says former postdoc at MIT’s Center for Bits and Atoms Patricia Stathatou, an incoming assistant professor at Georgia Tech and lead author, with Devashish Gokhale, SM ’22, PhD ’24 (now a University of Illinois postdoc), of a paper on the work. “The fact that the yeast themselves are bio-based, benign, and biodegradable is a significant advantage over traditional technologies.”