Authors
Elkassas, S. M., Ely, T., Zhivkova, T., Patterson, A., Weeks, K., Mitchell, S., Hayes-Guastella, L., Nathan, V., Serres, M., Shock, E., Girguis, P., German, C., Klein, F., Seewald, J., Huber, J. A.
Abstract
Evidence from the Cassini mission confirmed that Saturn's moon Enceladus hosts a subsurface alkaline ocean where rock-water reactions may generate redox disequilibria capable of supporting microbial metabolisms. To investigate potential microbial survival under simulated Enceladus ocean conditions, we used thermodynamic modeling to develop a salt formulation consistent with one possible Enceladus ocean composition and supplemented it with putative microbial energy sources to create a growth medium. The medium was inoculated with samples from diverse ocean world analog environments on Earth to determine which microorganisms could persist under Enceladus-like conditions. The microorganisms persisting in this geochemically bounded medium were heterotrophic, metabolically versatile bacteria with low carbon requirements. Genomic and physiological analyses further showed the presence of multiple stress-response pathways, sodium- based bioenergetic systems, osmoregulation strategies, and other adaptations consistent with survival in alkaline, low-nutrient settings. These results suggest that some stress-tolerant heterotrophic bacteria may serve as useful model organisms for life in Enceladus' subsurface ocean. These findings demonstrate the value of geochemically modeled media as a framework for constraining habitability, identifying relevant biosignatures, and probing potential microbial survival strategies beyond Earth.
Preprint server:
bioRxiv
The authors list and abstract were imported from bioRxiv on 03 Jul 2026.
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