the microbe ate uranium (byproducts)

Another breakthrough in origin-of-life research: a gold bug, but not outta Poe.

Chivian's analysis shows that D. audaxviator gets its energy from the radioactive decay of uranium in the surrounding rocks. It has genes to extract carbon from dissolved carbon dioxide and other genes to fix nitrogen, which comes from the surrounding rocks. Both carbon and nitrogen are essential building blocks for life as we know it, and are used in the building blocks of proteins, amino acids. D. audaxviator has genes to produce all the amino acids it needs.

D. audaxviator can also protect itself from environmental hazards by forming endospores – tough shells that protect its DNA and RNA from drying out, toxic chemicals and from starvation. It has a flagellum to help it navigate.

"One question that has arisen when considering the capacity of other planets to support life is whether organisms can exist independently, without access even to the Sun," says Chivian. "The answer is yes and here's the proof. It's philosophically exciting to know that everything necessary for life can be packed into a single genome."

It's quite probable that the bacterium is over 3 million years old. If it can survive there, who knows what might be living elsewhere.