Taking Bio-Recycling to the Next Level
Elizabeth Skovran with student researchers in her lab. Photo by Robert C . Bain.
You’d be forgiven for thinking the idea comes straight out of science fiction: Researchers are genetically engineering bacteria to eat the rare earth metals in electronic waste, which can then be recovered to power everything from electric cars to wind turbines to cell phone screens.
But Elizabeth Skovran, professor of biological sciences at San José State, along with colleagues at UC Berkeley, has filed a provisional patent to do precisely that. It all started, she explains, in 2011, when a published paper suggested that a specific group of bacteria called methylotrophs “could use rare earth metals for growth as part of their metabolism.” At the time, Skovran says, “Nobody in my field initially believed that.” But it was true. So like all good scientists, Skovran and her team started asking more questions.
“We started exploring,” she explains, “and then we got the idea. There are all these rare earth metals in our electronic devices. I wonder if our organism could use those. Could it grow using a computer hard drive magnet or a smart phone?” She actually scavenged around SJSU for old electronics and began literally breaking them apart into small pieces, which she then used to “feed” the bacteria, and sure enough, the bacteria obtained rare earths as a result.
An Alternative to Mining
Rare earths, metals that include a row of elements in the periodic table called the lanthanide elements, along with two others, are crucial to modern life. “Basically, our civilization runs on them,” Skovran says. “They’re in your computer hard drive magnets. They’re in the phosphores of your cell phone screens. They’re in our green energy technologies like wind turbines and catalytic converters for our electric cars. So we really depend on these.”
But they’re incredibly environmentally destructive to mine (the materials released in mining are toxic, and can poison groundwater, threaten biodiversity and cause cancer). This type of mining is rarely done in the U.S., so the United States is highly dependent on China and other mining nations for supplies of these metals.
Skovran’s team’s research could potentially disrupt this – and it could prove to be an environmentally friendly way of obtaining these metals as well, recovering and recycling the rare earths in old electronic waste for a decidedly useful purpose. “We wouldn’t have to be reliant on foreign nations for this really critical group of metals,” she states.
The process could be a game-changer, but there are many hurdles to overcome. One is cost-effectiveness. Another is scale. Skovran and her researchers (many of whom are San José State undergraduates) are working on a very small scale; her partnership with UC Berkeley and Livermore National Laboratories will allow them to expand. Berkeley has the capacity to grow the bacteria cells in several liter bioreactors and then scale up further to test various strains of bacteria.
And then there’s the question of the bacteria itself. In their natural state, the bacteria only extract the rare earths they need to reproduce, and leave the rest behind. In order to harvest the amount of rare earth metals needed to be cost competitive, Skovran and her team need to genetically engineer the bacteria to essentially “overeat,” allowing them to harvest more and more material from the electronic waste. Another issue? When the bacteria extract rare earths from electronic waste, they’re also exposed to toxic metals and chemicals inside it, and they need to be engineered so that they’re resistant to the toxicity.
As Skovran explains, “A lot of what we’re doing right now is basically taking all these separate mutations that enhance what we’re trying to do, whether that’s take up rare earths, store the rare earths, or become resistant to electronic waste, and combining all of them into a single strain of bacteria that we’ll use to recover these rare earths.”
Skovran and her team (including colleagues at Berkeley and Lawrence Livermore National Labs) have applied for a provisional patent for the process, and they have a manuscript under peer review on the bacterial platform. They also hope to build partnerships with companies to help facilitate this advanced electronic waste recycling. She mentions that some companies are already working to extract other valuable materials (like platinum and silver) from old electronics, and adds, “We see this as a pipeline where our process feeds into [other electronic recycling systems]. That way we’ll get a more holistic recovery of different items that would be valuable in the electronic waste. We can imagine licensing out the technology.”
In fact, Nathan Good, one of Skovran’s co-inventors, won a 2023 Activate Fellowship, a two year fellowship to investigate the viability of turning their concept into a profitable product/company.
“We never had a clue when we started this work that this could turn into not just an actual business, but also something that would really benefit society,” she says. “I’m very excited that we at SJSU are able to contribute to protecting the environment and solving some of the issues with mining for these metals.”