“Stowaway microbes from Earth could confound any attempts to find actual extraterrestrial life on other planets.” A team of scientists led by Rakesh Mogul from California State Polytechnic University at Pomona has discovered one of the bacteria Acinetobacter’s survival tricks: These microbes can eat the very cleaning products that are meant to banish them. “You can clean the rooms out and sterilize them, but microbes are still there,” says Mogul. “To be a bit Jurassic Park about it: Life will find a way.”
Few places are as hard for microbes to infiltrate as the clean rooms in which NASA assembles its spacecraft, continues Ed Young in The Atlantic. Those drifting in through the air must run a gauntlet of filters. Those hitching a ride on employees find their paths barred by face masks and full-body hooded coveralls. Those that actually manage to land on a surface will find a world of famine and drought, devoid of water and nutrients. If they survive, most will be wiped off when the clean rooms’ walls, floors, and contents are assiduously and repeatedly scrubbed with alcohol-based solvents
All this is in aid of “planetary protection”—the business of stopping Earth microbes from hitching a ride on our spacecraft and contaminating other worlds. NASA is bound to this principle by international treaty, and makes every effort to uphold it. After all, stowaway microbes from Earth could confound any attempts to find actual extraterrestrial life on other planets.
But it’s impossible to sterilize surfaces completely. Even nasa clean rooms have their own microbiomes—a common community of super-hardy species that somehow withstand the rigorous disinfection procedures. These communities are dominated by Acinetobacter bacteria, which are typically found in soil and water. While other microbes disappear during the cleaning process, Acinetobacter persists. Scientists have isolated strains from the surface of the Mars Odyssey orbiter, from the floors on which the Mars Phoenix lander was assembled, from the exterior of the International Space Station, and even from the station’s drinking water.
Mogul’s team, which was mostly made up of undergraduate students, took Acinetobacter strains that had been recovered from clean rooms, and reared them on vanishingly low levels of nutrients. Under these extremely restrictive diets, the bacteria could grow on ethanol as their main fuel. They burned it for energy, and they used its carbon to make their own DNA, proteins, and other essential molecules.
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