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Bacterial strains isolated from the International Space Station

Researchers have discovered three bacterial strains aboard the International Space Station that may help create the fuel to allow plants to withstand stressful situations, e.g., on Mars.


The genus Methylobacterium contains more species than any other genera within the family Methylobacteriaceae. Species of this genus are gram-negative, rod-shaped bacteria. There are currently 45 species in the genus Methylobacterium, which are ubiquitously present in a wide variety of habitats. Methylobacterium species are involved in nitrogen fixation, phosphate solubilisation, abiotic stress tolerance, plant growth promotion, and also biocontrol activity against plant pathogens.

Isolation on the International Space Station

In an ongoing Microbial Tracking experiment on the International Space Station (ISS), experts isolated four strains belonging to the family Methylobacteriaceae. The team identified one strain as Methylorubrum rhodesianum, whilst the other three strains were previously unknown and belong to a novel species. The researchers specifically gave these strains the designations IF7SW-B2T, IIF1SW-B5, and IIF4SW-B5. Genetic analysis also showed them to be closely related to Methylobacterium indicum. The phylogenetic and genetic distinctiveness, and differential phenotypic properties of these strains were sufficient for the team to categorise them as members of a species distinct from other Methylobacterium species. In honour of the renowned Indian biodiversity scientist, Dr Ajmal Khan, the team proposed to call the novel species Methylobacterium ajmalii. Their findings were published in Frontiers in Microbiology.

The team hope that these strains may possess biotechnologically useful genetic determinants for growing crops in space. Growing plants in extreme conditions where resources are minimal will be essential for future colonisation and long space missions. Therefore, isolation of novel microbes to help promote plant growth under stressful conditions will be beneficial.

This study is part of an ongoing surveillance mission with experts monitoring eight locations on the ISS for bacterial growth. These sample areas include where the crew assembles or where they are conducting experiments. The team hope that in the future, instead of bringing samples back to Earth for analyses, an integrated microbial monitoring system that collects, processes, and analyses samples in space can be used.

Image credit: By 3DSculptor –