Bacteria can extract lithium, cobalt, manganese, and other minerals from batteries and e-waste.

Some bacteria have been proven to synthesize metal nanoparticles from their surroundings, apparently as a detox method to protect themselves from poisoning – and a team at the University of Edinburgh aims to use them to extract lithium, cobalt, manganese, and other minerals from old batteries and e-waste.

Named The Horsfall Group, the researchers have proposed a method using specific microorganisms to extract rare metals essential for the development of green technology.

According to the research group's website, "Our disruptive innovations will lead to the development of unique and sustainable new products, derived from wastes and by-products, and demonstrating their cost-efficient and energy-saving production using novel biomanufacturing technologies."

A growing need

The United Kingdom's automotive industry, a major contributor to the economy with over 1 million cars produced annually, faces a growing challenge in managing end-of-life electric vehicle batteries, not to mention e-waste, with the carbon footprint expected to steadily increase from production to end-of-life management as electric vehicle adoption continues. By 2040, an estimated 1 million EVs will reach the end of their lifecycle each year, generating around 500,000 metric tons of batteries for recycling.

Efficient recycling is crucial not only for environmental reasons but also for the U.K.'s limited supply of key battery materials like cobalt, lithium, and nickel, which would otherwise lead to increased dependency on imports and raise potential strategic concerns. Also, due to the limited availability of metals, supply security, and scarcity have emerged as global concerns.

"All those photovoltaics, drones, 3D printing machines, hydrogen fuel cells, wind turbines, and motors for electric cars require metals – many of them rare – that are key to their operations," Louise Horsfall, chair of sustainable biotechnology at the University, told The Guardian in an interview.

Researchers have emphasized a global need to transition to a circular, more sustainable economy where waste is efficiently utilized as a feedstock and former waste streams are repurposed to fit into a materials cycle.

Microbial recycling

The Horsfall Group recommends microbes as an innovative key to a greener recycling process.

Bacteria are capable of performing unique and complex processes, such as synthesizing metal nanoparticles, which researchers believe is a detoxification mechanism, attaching to metal atoms and converting them into nanoparticles to avoid being poisoned.

Horsfall and her team have harnessed these bacterial strains in experiments to recycle waste from electronic batteries. According to the Guardian article, the bacteria targeted specific metals in dissolved e-waste, depositing them as solid compounds.

"Using Synthetic Biology tools and techniques, alongside an iterative design, build and test cycles we aim to enhance, manipulate and standardize the manufacture of these nanosize precipitates as high-value products," said the team.

Initially they successfully extracted manganese, followed by nickel and lithium. Using different bacterial strains, they also managed to extract cobalt and nickel.

The bacteria used in these processes are naturally occurring strains. Looking ahead, Horsfall and her team intend to use gene-edited bacteria to enhance metal extraction efficiency, such as further separating the cobalt and nickel, a capability they don't have yet.