Siderite and vivianite as energy sources for the extreme acidophilic bacterium Acidithiobacillus ferrooxidans in the context of mars habitability

Author(s)

Silva, Gabriel Goncalves ; Vincenzi, Roberta Almeida ; de Araujo, Gabriel Guarany ; Venceslau, Sara Jessica Soja ; Rodrigues, Fabio

• Document type: Journal article
• Source: SCIENTIFIC REPORTS; v. 14, n. 1, p. 16-pg., 2024-06-27.

Abstract

Past and present habitability of Mars have been intensely studied in the context of the search for signals of life. Despite the harsh conditions observed today on the planet, some ancient Mars environments could have harbored specific characteristics able to mitigate several challenges for the development of microbial life. In such environments, Fe2+ minerals like siderite (already identified on Mars), and vivianite (proposed, but not confirmed) could sustain a chemolithoautotrophic community. In this study, we investigate the ability of the acidophilic iron-oxidizing chemolithoautotrophic bacterium Acidithiobacillus ferrooxidans to use these minerals as its sole energy source. A. ferrooxidans was grown in media containing siderite or vivianite under different conditions and compared to abiotic controls. Our experiments demonstrated that this microorganism was able to grow, obtaining its energy from the oxidation of Fe2+ that came from the solubilization of these minerals under low pH. Additionally, in sealed flasks without CO2, A. ferrooxidans was able to fix carbon directly from the carbonate ion released from siderite for biomass production, indicating that it could be able to colonize subsurface environments with little or no contact with an atmosphere. These previously unexplored abilities broaden our knowledge on the variety of minerals able to sustain life. In the context of astrobiology, this expands the list of geomicrobiological processes that should be taken into account when considering the habitability of environments beyond Earth, and opens for investigation the possible biological traces left on these substrates as biosignatures. (AU)

• FAPESP's process: 12/06642-1 - Formation and properties of adducts of organic hydroxy-compounds with carbonate in aqueous medium and biological conditions
• Grantee: Claudimir Lucio Do Lago
• Support Opportunities: Regular Research Grants
• FAPESP's process: 18/21076-9 - Structure of the Xanthomonas citri type IV pilus secretin
• Grantee: Gabriel Guarany de Araujo
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 16/06114-6 - The Neoproterozoic Earth System and the rise of biological complexity
• Grantee: Ricardo Ivan Ferreira da Trindade
• Support Opportunities: Research Projects - Thematic Grants