Caffeine-Eating Bacteria Revealed

Think you live on caffeine? Four species of bacteria that thrive solely on the substance have you beat.

But these microbes get their caffeine fix from regular dirt—not the coffee which so many of us depend on to function. For example, people in the U.S. buy more than 2.5 billion pounds of coffee every year, according  to USAID.

About 60 species of plants naturally produce caffeine, which contains carbon, hydrogen, nitrogen, and oxygen. It’s also, I was surprised to learn, similar in structure to some of the molecules that make up our DNA, University of Iowa Ph.D. student Ryan Summers told me. (Get a genetics overview.)

Coffee is one of several plants that produces caffeine.

Photograph courtesy John Pavelka

Cool as they are, these caffeine-eating critters are already known to science. What’s new about Summers’ work is finding out how the bacteria actually process the caffeine. To be more exact, he found four newly discovered digestive proteins that break caffeine down into xanthine and then to carbon dioxide and ammonia—producing formaldehyde in the process.

“It’s like looking at a clock and finding the gears that are responsible for turning the hands,” said Summers, who presented his findings at the American Society for Microbiology meeting in New Orleans in May.

Figuring this out may benefit pharmaceutical industries, since the bacteria produce natural byproducts that drug developers can use as building blocks to create medicines. It’s expensive to synthesize these byproducts in the lab, so having a cheap bacterial workforce would be useful, Summers said.

Sadly (at least to me) he added the tiny critters don’t seem to get a miniature version of a caffeine buzz.

“It really is just serving as a basic food source, as we use sugars.”

Overall bacteria are sort of the “give it to Mikeys” of the natural world—they consume everything from petroleum to rocks to even the metal on the sunken Titanic.

(See “Rock-Eating Bacteria ‘Mine’ Valuable Metals.”)

For instance, they’ve done wonders gobbling a lot of the oil from the Gulf spill. Energy-rich oil “is basically butter” to these organisms, marine chemist Chris Reddy told me in 2010. “Any self-respecting bacteria is going to want to eat it.”

Bacteria can also thrive in the most extreme of places, from the coldest reaches of Antarctica to smoking lava vents of the deep sea.

As biological and chemical oceanographer Patricia Yager put it earlier this year, “microorganisms find a way.”

Check out more weird coverage on National Geographic News.

Wildlife

Christine Dell'Amore, environment writer/editor for National Geographic News, has reported from six continents, including Antarctica. She has also written for Smithsonian magazine and the Washington Post. Christine holds a masters degree in journalism with a specialty in environmental reporting from the University of Colorado at Boulder. Her book, South Pole, was published in 2012.