Exploring non-NaCl Salts as Potential Habitats for Extraterrestrial Life - EXOSALT

• Applicant: Dr. Jacob Heinz
• Subject Area: Microbial Ecology and Applied Microbiology ; Astrophysics and Astronomy
• Term: since 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 455070607

On Earth, sodium chloride (NaCl) stands as the most prevalent soluble salt, serving as the primary solute within seawater. Consequently, extensive research has focused on the potential of microbial life to withstand elevated concentrations of this salt, even reaching saturation. However, a diverse array of other salt types has been identified both on Earth and on celestial bodies, such as nitrate, perchlorate or calcium salts in the Atacama Desert, Chile, as well as on Mars. Unfortunately, our understanding of the capacity of these non-NaCl salt environments to support halotolerant life and preserve biosignatures remains limited, necessitating more rigorous examination. In pursuit of this objective, we will investigate samples from hypersaline environments in Chile comprising salts other than NaCl. The samples will be analyzed regarding their geochemical characteristics and microbial compositions to investigate correlations between geochemical and microbiological parameters. Furthermore, cultivation experiments will be conducted enabling the isolation of halophilic species growing in the presence of non-NaCl salts. Subsequently, these organisms, together with well-studied model organisms, will be investigated regarding their salt-specific adaptations and stress responses with state-of-the-art proteomic and metabolomic methodologies. Interpretation of the results from these analyses will help to evaluate the potential of hypersaline non-NaCl environments to serve as habitats for terrestrial and putative extraterrestrial lifeforms. Furthermore, metabolites produced by stress-induced biosynthesis will be analyzed regarding their potential to serve as chemical biosignatures for space missions or as bioproducts for medical, pharmaceutical, cosmetical or other industries. This research not only enhances our understanding of extremophile adaptation and our capabilities to potentially detect life in extraterrestrial hypersaline environments but also holds promise for in-situ resource utilization approaches involving, for example, perchlorate-containing Martian regolith in future human Mars exploration endeavors.

• DFG Programme: Research Grants