#Caltech scientists discover elusive metal-eating bacteria

Manganese oxide nodules generated by the bacteria discovered by the Caltech team.
Hang Yu/Caltech

Scientists have discovered a new type of bacteria that survives by gobbling metal, according to a new study.

Researchers have long believed that a metal-munching bacteria existed but weren’t able to prove it until Jared Leadbetter, a microbiologist at Caltech in Pasadena, launched an experiment.

He left a glass jar covered in manganese, a common chalk-like white metal, in his office sink for months — and returned to find it covered in a mysterious dark substance, he said in a press release.

“I thought, ‘What is that?’ ” Leadbetter said. “I started to wonder if long-sought-after microbes might be responsible, so we systematically performed tests to figure that out.”

Researchers soon learned the compound had been oxidized by a bacteria that wants to dine on everything from cars to cutlery.

The yet-to-be-named bacteria is most likely found in California tap water, according to the study published Tuesday in the journal Nature, which makes no mention of the bacteria’s impact on people.

To prove the bacteria has a metal diet, Leadbeater and his team coated more jars with manganese and sterilized them using scorching steam. They then looked for 70 species of bacteria, eventually ruling them all out except the new one.

“This discovery fills a major intellectual gap in our understanding of Earth’s elemental cycles, and adds to the diverse ways in which manganese, an abstruse but common transition metal, has shaped the evolution of life on our planet,” said Caltech geobiologist Woodward Fischer, who was not involved with the study.