Bacteria build “Iron Man” suits by soaking up toxic cobalt


Bacteria may seem like pretty simple lifeforms, but their ingenuity keeps surprising scientists. The latest example is a species called Geobacter sulfurreducens, which has now been found to survive exposure to toxic cobalt by building a metal “suit” like a tiny Iron Man.

The Geobacter genus is made up of some particularly resourceful bacteria. They can “breathe” rust, build conductive nanowires and even produce electricity, meaning they could be useful for creating microbial fuel cells that generate electricity from mud or humidity.

And now scientists at Michigan State University have uncovered a new ability. Geobacter sulfurreducens appears to be able to protect itself from cobalt, which is toxic to most bacteria and other organisms. The bugs essentially mine cobalt from rust, and instead of letting it penetrate through their membranes they wrap themselves in it.

“They form cobalt nanoparticles on their surface,” says Gemma Reguera, lead author of the study. “They metallize themselves and it’s like a shield that protects them. It’s like Iron Man when he puts on the suit.”

The researchers demonstrated the ability in the lab, exposing Geobacter to high levels of cobalt. The bacteria shrugged it off, with microscope images clearly showing the bugs shrouding themselves in the metal and continuing to thrive.

The team says that this newfound talent means the bacteria could eventually be put to work extracting cobalt from discarded lithium-ion batteries for reuse, or to soak it up in the environment. The next steps in the research are to investigate if Geobacter could also soak up other toxic metals – in particular, cadmium.

The research was published in the journal Frontiers in Microbiology., 10 January 2021