Metal-Eating Microbes

Photo: Hang Yu/Caltech

Caltech microbiologists have discovered bacteria that feed on manganese. “These are the first bacteria found to use manganese as their source of fuel,” says Jared Leadbetter, professor of environmental microbiology, who made the discovery with postdoctoral scholar Hang Yu (MS ’13, PhD ’17). Leadbetter found the bacteria after performing unrelated experiments using a light chalk-like form of manganese. He had left a glass jar soiled with the substance to soak in his Caltech office sink before departing for several months to work off campus. When he returned, the jar was coated with a dark material that tests revealed to be oxidized manganese generated by newfound bacteria that had likely come from the tap water itself. Further research revealed that these bacteria can also use manganese to convert carbon dioxide into biomass. Previously, researchers knew of bacteria and fungi that could oxidize manganese, but they had only speculated that microbes might be able to harness the process to drive growth.