Scientists have discovered microbes that feed and breathe on electricity. The discovery may force scientists into completely rethinking the fundamentals of how life works – both here on earth and out in space.
Kenneth Nealson is looking awfully sane for a man who’s basically just told me that he has a colony of aliens incubating in his laboratory.
We’re huddled in his modest office at the University of Southern California (USC), on the fifth floor of Stauffer Hall. Nealson is wearing a rumpled short-sleeve shirt, a pair of old suede loafers, white socks—your standard relaxed academic attire—and leaning back comfortably in his chair. An encouraging collection of academic awards hangs on one wall. Propped behind him is a well-worn guitar, which he sometimes breaks out to accompany his wife’s singing. And across the hall is the explanation for his quiet confidence: beakers and bottles full of bacteria that are busily breaking the long-accepted rules of biology.
Life, Nealson is explaining, all comes down to energy. From the mightiest blue whale to the most humble microbe, every organism depends on moving and manipulating electrons; it’s the fuel that living matter uses to survive, grow, and reproduce. The bacteria at USC depend on energy, too, but they obtain it in a fundamentally different fashion. They don’t breathe in the sense that you and I do. In the most extreme cases, they don’t consume any conventional food, either. Instead, they power themselves in the most elemental way: by eating and breathing electricity. Nealson gestures at his lab. That’s what they are doing right there, right now.
“All the textbooks say it shouldn’t be possible,” he says, “but by golly, those things just keep growing on the electrode, and there’s no other source of energy there.” Growing on the electrode. It sounds incredible. Nealson pivots on his chair to face me and gives a mischievous grin. “It is kind of like science fiction,” he says. To a biologist, finding life that chugs along without a molecular energy source such as carbohydrates is about as unlikely as seeing passengers flying through the air without an airplane.
That discovery comes with some sizable implications. On a practical level, electric bacteria could be harnessed to create biological fuel cells or to clean up human waste. Nealson tells me that one of his former students just got a grant to build a bacteria-powered sewage system. But more to the point, such microbes appear to comprise a vast, largely unexplored realm of life on this planet. There’s a chance they are an important part of the biodiversity on planets beyond ours too.
Nealson never utters the word “aliens,” but it hangs heavily over the conversation. His bacteria are unlike anything we’ve ever encountered, and they are forcing us to rethink life as we know it.