Simulated geochemistry of the early earth and exoplanets fuels a hydrogen-dependent primordial metabolism

This study investigates how abiotic hydrogen (H₂) production can support early and extraterrestrial life. Experiments simulating early Earth conditions show that iron-sulfide minerals (mackinawite and greigite) can generate enough H₂ to sustain the growth and metabolism of hydrogen-dependent methanogenic archaea, promoting CO₂ fixation via the acetyl-CoA pathway.

Extending this approach to Saturn’s moon Enceladus, the study demonstrates that simulated alkaline ocean conditions - rich in H₂ and dissolved inorganic carbon - can support the growth of methanogens even at extremely high pH. Despite low CO₂ availability, these organisms adapt by upregulating the acetyl-CoA pathway, enabling efficient carbon fixation.

Overall, the results suggest that abiotic H₂ from geochemical processes can fuel primitive metabolism on early Earth and potentially sustain life in extraterrestrial environments like Enceladus.