Iron/manganese-oxidizing bacteria from ferruginous environments of Minas Gerais (Brazil): implications in Geomicrobiology and Astrobiology

• Grant number: 20/03430-0
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• Effective date (Start): May 01, 2021
• Effective date (End): March 31, 2024
• Field of knowledge: Biological Sciences - Microbiology
• Principal Investigator: Fabio Rodrigues
• Grantee: Maicon Nascimento Araújo
• Host Institution: Instituto de Química (IQ). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated scholarship(s): 22/00016-3 - Surface reactivity of the sheath-forming Iron/manganese-oxidizing bacterium leptothrix: Implications in sheath encrustation and metal mobilization, BE.EP.DD

Abstract

Iron and manganese are elements involved in several geochemical processes mediated by microorganisms. Brazil presents several surface and subsurface (caves) metal-rich environments that represent promising sites for studying microbial adaptive and evolutionary mechanisms, as well as aspects of local biogeochemistry and their implications for biogenicity criteria and detection of biosignatures in rocks. Two interesting places for such studies are the Monte Cristo cave and the Rio Grande stream, in Diamantina (MG). However, despite the potential of this region to support Fe and Mn-oxidizing microorganisms, there are still no studies on metabolic potential, microbe-mineral interaction and the ecological role of these microbial communities in the ferruginous Diamantina's caves and streams, making this proposal a pioneer. Therefore, the objective of the present work is to describe the structure of the microbial community regarding its functional diversity in the environments described using the metagenome technique, as well as to identify iron and manganese-oxidizing microorganisms that are cultivable, and isolate them. Finally, the strains isolated will have their physiological characteristics described in order to elucidate geomicrobiological interactions associated with the formation of potential biosignatures. Therefore, this study can contribute to a better understanding of the history of life on Earth, since these bacteria that are biomineralized by binding Fe and Mn has an similarity with ancient organisms found in the fossil record. In addition, the information generated through the integration of different techniques proposed in this study may contribute to future search missions for biosignatures on Mars and other ferruginous environments. (AU)