Bacteria as Pioneers in Space Exploration

In August 2019, a small container filled with soil bacteria known as Sphingomonas desiccabilis arrived at the International Space Station (ISS). The ESA astronaut and astrobiologist Luca Parmitano received the container and provided the bacteria with a nutrient solution along with a piece of basalt from Iceland, which they are known to thrive on, even on Earth. These bacteria are capable of extracting metals from rocks, a process utilized in large-scale mining known as 'biomining'. They can recover valuable resources such as vanadium and rare earth elements, which are increasingly sought after for sustainable technologies.

The objective of this experiment was to determine whether these bacteria could perform similarly under microgravity conditions, as well as in simulated Martian gravity created by centrifuges. The potential for these bacteria to assist in mining operations on Mars is significant, as they could provide essential materials from the planet's surface.

The research indicated that S. desiccabilis successfully adapted to the microgravity environment (as published in Nature Communications), although it is still uncertain if they will effectively process the fine-grained regolith that covers Mars, which is a focus for those aiming to make the planet habitable. Human exploration will require utilizing local resources, and these bacteria could be pivotal in extracting necessary materials for life support, construction, food, and breathable air.

On Mars, the atmosphere is predominantly carbon dioxide (96%), with no oxygen available. However, cyanobacteria have the ability to utilize CO2 for photosynthesis, producing oxygen as a byproduct. This process could potentially create breathable air for future inhabitants.

In addition to CO2 and sunlight, these bacteria require essential metals like manganese and iron, which are present in the Martian regolith. However, this regolith is contaminated with hazardous substances, primarily perchlorates, that need to be neutralized before the bacteria can thrive. Likewise, ice found on Mars, though a potential source of water, is also contaminated and poses similar challenges.

Research suggests that another bacterium, Pseudomonas stutzeri, could be utilized to detoxify perchlorates, which are used in rocket fuel and can contaminate the environment. Adam Arkin, who leads a research initiative at the University of Berkeley in collaboration with NASA, aims to explore the capabilities of this bacterium in Martian conditions. The project, known as the Cubes (Center for Utilization of Biological Engineering in Space), continuously generates new ideas for utilizing bacteria in space, although many of these concepts do not receive widespread attention.