A newly published study reveals that a bacterium discovered in NASA clean rooms can enter a dormant state, raising concerns about its potential presence on Mars. The bacterium, known as Tersicoccus phoenicis, was first identified in 2007 in two separate clean rooms located approximately 2,500 miles (4,000 kilometers) apart. This research, published in the journal Environmental Microbiology, provides insights into how this microbe survives extreme sterilization efforts.
A Surprising Discovery in Clean Rooms
Clean rooms are designed to eliminate microorganisms that could contaminate spacecraft and jeopardize future missions. To achieve this, NASA employs rigorous cleaning methods, including heating, chemical treatments, and radiation exposure. Despite these measures, T. phoenicis not only survived but also eluded detection during sterilization checks.
When NASA announced the discovery of this microbe in 2013, the agency confirmed it posed no health risks. However, the recent findings suggest that the bacterium has remarkable survival abilities. “It is not dead. It was playing dead,” said Madhan Tirumalai, the lead author of the study and a microbiologist at the University of Houston. This statement highlights the bacterium’s ability to enter a dormant state, which mimics death.
Understanding Dormancy and Survival
The study aimed to investigate the survival mechanisms of T. phoenicis. Researchers deprived the bacteria of nutrients and placed them on sterile glass Petri plates, leading to dehydration. Within 48 hours, the bacteria entered a dormant state, appearing lifeless. Remarkably, they remained in this state for an entire week, even after attempts to revive them with nutrients.
However, the study revealed that exposing the bacteria to a specific protein could restore their biological activity. “The fact that this bacterium can intentionally suspend its metabolism makes survival on spacecraft surfaces or during deep-space cruise more plausible than previously assumed,” remarked Nils Averesch, a microbiologist at the University of Florida, who was not involved in the study.
This research opens up new avenues for understanding microbial life and its potential to survive in extreme environments, such as those found in space.
Concerns About Contamination on Mars
One of the clean rooms where T. phoenicis was identified was used during preparations for NASA’s Phoenix Mars lander, which successfully launched and landed on Mars. The possibility of this resistant bacterium hitching a ride to the Red Planet raises questions about planetary protection and contamination.
Experts suggest that while the idea of contamination is concerning, the chances of T. phoenicis surviving on the Martian surface are low. “Anything directly exposed on the Martian surface is unlikely to survive,” Averesch noted. The bacterium’s unique adaptations may also indicate that it evolved specifically to thrive in spacecraft clean rooms, as it has not been found in any other environment.
The implications of this research extend beyond space exploration. Understanding how T. phoenicis survives could lead to improved cleaning protocols in clean rooms, ensuring that future missions remain free of Earthly microbes. This study exemplifies the incredible resilience of the smallest forms of life and their capacity to adapt to extreme conditions.
