Abstract EANA2026-87

Abstract:

Future long-term human exploration of the Moon, Mars, and asteroids will require sustainable In-Situ Resource Utilization (ISRU) strategies capable of reducing dependence on Earth-supplied materials. Among the most promising approaches, space biomining exploits microbial metabolisms to mobilize and recover critical elements directly from extraterrestrial substrates. This work investigates the potential of the extremotolerant bacterium Sphingomonas desiccabilis and the acidophilic chemolithotroph Acidithiobacillus ferrooxidans for microbial metal extraction in planetary environments and their terrestrial analogues.

S. desiccabilis was investigated through comparative bioleaching experiments involving seven terrestrial and extraterrestrial substrates, including meteorites, e.g., eucrite, basaltic rocks (from Iceland), and samples from the Sudbury impact structure (in Canada). The bacterium demonstrated substrate-dependent mobilization of critical trace metals under circum-neutral pH conditions, selectively extracting Ce (up to 10.6 %), Th (up to 1.5 %), and additional industrially relevant elements such as Pd, Pt, Mo, and W. The results highlight how mineralogical composition strongly influences biomining efficiency, emphasizing the importance of tailoring microbial approaches to specific planetary substrates and low-grade rocks relevant to future space missions.

In parallel, A. ferrooxidans was investigated in Mars and icy moon analog environments, including hydrothermal massive sulfides deposits and basaltic substrates from the East Pacific Rise (Hydrothermal Tica Vent), and alpine cryoconites. The experiments revealed efficient mobilization of elements such as As, Cu, Ga, Mn, U, Th and W, highlighting the metabolic versatility of acidophilic microorganisms in extreme geochemical systems.

Beyond extraterrestrial applications, these findings have important implications for sustainable technologies on Earth, including bioremediation, recovery of rare earth elements (REEs) and platinum group elements (PGEs), recycling of low-grade materials and waste streams, and radionuclide recovery from contaminated environments. Overall, this research expands our understanding of microbe-mineral interactions under extreme conditions and supports the development of biologically driven resource extraction technologies for both planetary exploration and a greener circular economy on Earth.

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