UC biologist unlocks secret of metal-munching bacteria

UC College of Arts and Sciences Assistant Professor Annette Rowe is studying the power of microbes that can use minerals to store an electrical charge and then recover that energy when needed — like an organic battery.

But some bacteria and other organisms are able to live off inorganic minerals. They produce energy through chemical reactions with metals such as iron or sulfur using compounds such as carbon dioxide to build more of themselves.

“A lot of minerals oxidize naturally. But is it the microbe doing it or the environment?” Rowe said. “The work we’ve been doing is decoupling some of that.”

Rowe said there is growing interest in understanding these processes to harness energy and create better technology.

“One potential benefit is replacing catalysts on electrodes. Usually these are made from rare earth elements like platinum or palladium. They are expensive to mine,” Rowe said. “But biology can catalyze the same process and allow us to replace these rare earth elements with microbes that can do the same thing.”

Likewise, the research could help improve technologies that generate methane such as natural gas from sewage treatment. Most sewage treatment plants only efficiently generate 60 to 80% of methane through anaerobic digestion.

“We tend to just burn it off so it becomes another waste product,” she said. “Coming up with technologies that can take that 80% methane conversion to a 95% threshold would be very valuable.”

Rowe comes from a science family. Her parents are physicians. She considered studying virology but she became fascinated with the way our cells make energy.

Her research draws on chemistry, engineering and biology. She earned a doctorate in microbiology while working in an environmental engineering lab. 

“I wish I had paid more attention in physics,” she joked. “As a researcher, you’re going to have to learn things outside of your training.”

Rowe’s research also has implications for space exploration and the ongoing search for extraterrestrial life. If life exists outside Earth, it likely will be driven by geology or energy derived from heat rather than light, she said.

“It’s definitely never boring,” she said. “There’s a steep learning curve. And some frustration in being on the cutting edge. Nobody has done any of this before, so getting it to work will be a challenge.”

Featured image at top: UC College of Arts and Sciences Assistant Professor Annette Rowe is a 2023 recipient of an Early Career Grant from the National Science Foundation that will support her electromicrobiology research. Photo/Andrew Higley/UC Marketing + Brand