A new study has found that a “clean room” at NASA's Johnson Space Center in Houston, Texas isn’t so clean. In fact, it’s contaminated with fungi.
The clean room houses samples from space, including meteorite fragments, for future examination. But as Adam Mann reports for Science, a new analysis of the lab turned up many microbes from the genus Penicillium. The find could spell trouble for future work in the lab; the presence of Earthling microbes could contaminate samples from space.
As Mann reports, the findings, presented by geomicrobiologist Aaron Regberg of the Johnson Space Center at the 2018 Lunar and Planetary Science Conference in Texas last week, were part of a series of evaluations at the Johnson Space Center. The report comes as the room prepares to receive samples from Mars and Bennu, a carbon-rich, 1,600-feet-wide chunk of rock that likely formed during the birth of our solar system.
Regberg and his colleagues tested the floor, table and workbench of the lab that was used to process meteorites. The clean room is an enclosed area to avoid contamination, and samples of space rock are stored in nitrogen-filled cabinets at elevated pressures to prevent contaminants from entering, Mann reports.
On a cleanliness scale, however, this particular lab isn't intended to be as squeaky clean as it gets. On an international ratings system from 1 to 9, with class 1 being the cleanest, the room was only designed to be a class 6. And as Meghan Bartels reports for Newsweek, contamination is inevitable even in a room designed to be free from it. So the find isn't shocking.
But the results are notable. Unlike clean rooms at other facilities, between 83 percent and 97 percent of the microbes found at the room at the Johnson Space Center were fungi, not bacteria, Mann writes. And that's a problem. Fungi have the potential to penetrate samples and chemically alter them. Some fungi also produce the amino acids α-aminoisobutyric acid and isovaline, which are often found in carbon-rich asteroids. If this were to happen, it could meddle with test results, Regberg tells Mann.
Each passport photo–size area contained between four and 28 viable cells. Inside the air filter, results were much worse. Microbes were growing on the air filter used for nitrogen gas, though the fungi appeared to be separated from the actual samples.
"It feels like using those cleansing pore strips and really looking into it to find out what dirty stuff are pulled out from my nose!," Queenie Chan, a planetary scientist at Open University in the U.K. who relies on clean rooms for her research, tells Newsweek.
Some researchers are already rethinking whether their own work has been affected by contamination. Astrobiologist Daniel Glavin with NASA’s Goddard Space Flight Center tells Mann that he had previously detected α-aminoisobutryic acid on lunar soils stored at another NASA office he believes originated from meteorites crashing into the moon but now wonders whether it was a result of fungi.
Marc Fries, a spectroscopist at the Johnson Space Center who was not involved in the study, says the report is eye-opening, according to Science. “It drives home this point that fungi are an important part of microbial contamination,” he says.
It’s unclear why previous tests didn’t pick up on the fungi, but Regberg tells Mann it might be because they had never specifically looked for fungi before.
Scientists already have methods that could help them account for contamination when analyzing new samples, including identifying the exact chemical makeup of each compound to weed out the false positives.
As Bartels reports, a new clean room is being designed at the Johnson Space Center, and this new study will help researchers better control contamination.