Marcela Leal
Inner Workings: How bacteria could help recycle electronic wasteThe bacterium Chromobacterium violaceum is known for producing an antimicrobial agent called violacein. But C. violaceum offers more than medical applications. The bacterium might be capable of recovering precious metals from the massive quantities of electrical and electronic waste (e-waste) generated around the world. People tossed out 44.7 million metric tons of e-waste in 2016, a figure that’s on the rise. If scaled up, specially designed bacteria could offer an environmentally friendly cleanup alternative. Image credit: Shutterstock/aquatarkus. C. violaceum is one of several potential e-waste–processing microbes. Some bacteria produce chemicals that leach metals from electronic scrap. Others bind or absorb the metals. Researchers say these methods could be more sustainable than other extraction techniques, such as heating e-waste to high temperatures or adding toxic chemicals. So-called bioleaching is “a green process,” says Yen-Peng Ting, an environmental chemical engineer at the National University of Singapore. Yet bacteria aren’t perfect recyclers. Often, microbes can’t extract as much metal as heating or chemical processes do. “With the bacteria, generally the process is slower,” Ting acknowledges, citing research challenges. But genetic engineering of the right traits could help. And some scientists are already confident enough in the approach to commercialize it. Without question, e-waste is a huge problem. People tossed out 44.7 million metric tons of e-waste in 2016, and the figure is expected to reach about 52 million metric tons in 2021 (1). More people are buying electronic gadgets, and consumers tend to use some devices such as mobile phones for a short time. This rampant consumption, researchers wrote in a 2013 article, “has resulted in the generation of a torrential electronic waste stream” (2). Although the handling and processing of e-waste are hard to track, government documents and scientific reports suggest that only 20% of it is being properly recycled worldwide …