Four strains of bacteria, three of which were previously unknown to science, were found on the space station. They can be used to help grow plants during long-term spaceflight missions in the future.
The space station is a unique environment because it has been completely isolated from Earth for years, so a multitude of experiments have been used to study what kind of bacteria are present there.
Eight specific points on the space station have been continuously monitored for the past six years for the presence of microbes and bacterial growth. These areas include modules in which hundreds of scientific experiments are performed; a growing room where plants are grown; as well as places where the crew meets for meals and other occasions.
As a result, hundreds of bacterial samples were collected and studied, with a thousand more expectations to return to Earth for analysis.
The four strains of bacteria that the researchers isolated belong to the Methylobacteriaceae family. The microbes were taken from the samples along the space station, during the expeditions of the different crews that took place consecutively.
Methylobacter species are useful to plants, promoting their growth and fighting pathogens that affect them, among others.
One of the strains, Methylorubrum rhodesianum, was already known. But the other three rod-shaped bacteria were unknown – although by genetic analysis, scientists were able to determine that they were most closely related to the species of bacteria Methylobacterium indicum.
Lead researcher Kasthuri Venkateswaran and planetary protection engineer Nitin Kumar Singh, both of the Jet Propulsion Laboratory in Pasadena, California, worked on this research to understand the potential applications of bacteria.
The new strains may be “biotechnologically useful genetic determinants” to help grow plants in space, the scientists said in a statement. “In order to grow plants in extreme places where resources are minimal, isolating new microbes that help promote plant growth under stress is essential.”
Greens with leaves and radishes have been successfully grown on the space station, but the cultivation of crops in space is not without difficulties. Methylobacteria could be used to help plants overcome the stressors they face trying to grow outside the Earth.
However, the researchers pointed out that only time and experiments that use this bacterium to test their theory will show if it works.
Researchers also want to know more about these newly found bacteria.
“Because these three ISS strains have been isolated at different time periods and from different locations, their persistence in the ISS environment and their ecological significance in closed systems warrant further study,” the study authors wrote.
By the time humans reach Mars, the space station will serve as a test bed for a multitude of technologies and resources needed for long-term missions in deep space, the researchers said. This includes the study of microorganisms and how they affect life on the space station – and how they could be used.
“Because our group has expertise in growing microorganisms in extreme niches, we have been tasked by NASA’s Space Biology Program to analyze ISS for the presence and persistence of microorganisms,” said Venkateswaran and Singh.
Methylobacterium discovered during this study is also not harmful to astronauts.
“Needless to say, the ISS is an extremely cleanly maintained environment. Crew safety is the number one priority and therefore understanding human / plant pathogens is important, but beneficial microbes like this novel Methylobacterium ajmalii are also needed.”
Given the amount of bacteria found on the space station that is still awaiting analysis and the potential to discover new strains, the researchers hope that molecular biology equipment could be developed to study bacteria while on the space station.
“Instead of bringing samples back to Earth for analysis, we need an integrated microbial monitoring system that collects, processes and analyzes samples in space using molecular technologies,” the researchers said. “This miniaturized space-based technology – a development of biosensors – will help NASA and other space nations to conduct safe and sustainable space exploration for long periods of time.”