Bacteria breakthrough: Microbes help mine rare metals from old battery waste

Researchers have proposed a method using bacteria to extract rare metals essential for the development of green technology.

A team named The Horsfall Group at the University of Edinburgh aims to use microorganisms to extract lithium, cobalt, manganese, and other minerals from old batteries and discarded electronic equipment.

Several bacteria are able to decrease metal cations and generate precipitates of zero-valence, pure metals as a survival strategy against dangerous concentrations of metal cations.

“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,” according to the research group’s website .

Advancing circular economy

With the rapid rise in electric vehicle adoption in the UK—projected to grow from 1 in 200 today to 1 in 12 by 2030, and 9 in 10 by 2050—the carbon footprint of vehicles is expected to shift significantly from production to end-of-life management.

The UK’s automotive industry, a major contributor to the economy with over 1.7 million cars produced annually and a turnover of £77.5 billion in 2016, faces a growing challenge in managing end-of-life electric vehicle batteries.

By 2040, an estimated 1 million electric vehicles will reach the end of their lifecycle each year, generating around 0.5 million tonnes of batteries for recycling.

According to researchers, efficient recycling of these lithium-ion batteries is crucial not only for environmental reasons but also due to the UK’s limited supply of key battery materials like cobalt, lithium, and nickel.

Failure to recycle these materials would lead to increased dependency on imports, raising 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,” said Louise Horsfall, chair of sustainable biotechnology at the University, told Guardian .

Researchers highlight the need to transition to a circular, more sustainable economy in which we use the resources we have more wisely to address a global crisis. According to them, the fundamental tenets of a circular economy are that waste is an underutilized feedstock and that waste streams can be designed, constructed, and repurposed to fit into a materials cycle.

Microbial recycling

Aiming to find a solution to this impending crisis, researchers looked at microbes as the key to an innovative recycling process.

Bacteria are remarkable organisms capable of performing unique and complex processes, such as synthesizing metal nanoparticles. These bacteria likely do this as 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 to recycle waste from electronic batteries and cars. According to the Guardian, they dissolved the waste and then used bacteria to target specific metals, 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 researchers.

They initially successfully extracted manganese, followed by nickel and lithium . Using a different bacterial strain, they also managed to extract cobalt and nickel.

The bacteria used in these processes were naturally occurring strains. Looking ahead, Horsfall and her team intend to use gene-edited bacteria to enhance metal extraction efficiency, such as separating cobalt and nickel, a capability they currently lack.