Abstract_EANA2025-176

Abstract EANA2025-176

Role of Schreibersite in Amino Acid Polymerization Under Anoxic Conditions

Scott Green(1), Lee Cronin(2), Silke Asche(3), Geoff Cooper(2), Michael Jirasek(2), Matthew Pasek(4), Anna Neubeck(1)*

1Department of Earth Sciences, Uppsala University, Sweden 2Cronin Lab, Glasgow University, United Kingdom 3Agnostic Biosignatures Collective, Goddard Space Flight Center, MD, USA 4School of Geosciences, University of South Florida, USA

Prebiotic chemistry explores how early Earth conditions facilitated the formation of complex organic molecules, with mineral surfaces playing a crucial catalytic role. However, the mechanisms by which meteoritic minerals influenced amino acid (AA) polymerization under anaerobic conditions remain unclear. In this study, we investigated the catalytic potential of the meteoritic phosphide mineral schreibersite (FeNi)₃P under prebiotic, anaerobic conditions by polymerizing AA´s using schreibersite as a catalyst. Transition metal controls (Fe, Ni), schreibersite, and calcium phosphate were subjected to wet-dry cycling with five AAs in anoxic conditions (under N₂ gas) over six cycles. Our results show that the schreibersite mineral catalyzed AA polymerization and that schreibersite were a more potent catalyst than native metal powders of Ni or Fe alone. The main explanation for this result is that the schreibersite exists in a mixed oxidation state environment, which enhances electronic delocalization across the crystal lattice. The enhanced performance is likely due to multihybridization between Fe and Ni sites, which may lower the activation barriers forthe polymerization. In comparison with oxygenic experiments, the anoxic experiments showed a higher yield, which likely is due to the metal oxidation states, where in an anoxic environment, the Fe and Ni remain in lower oxidation states (Fe²⁺ and Ni⁰/Ni²⁺). These lower oxidation states have a higher electron density in their d-orbitals, making them more efficient at interacting with AA functional groups (–NH₂ and –COOH) whereas in an oxic environment, Fe and Ni are more likely to form Fe³⁺ and Ni³⁺, which have lower catalytic activity due to their preference for stable oxide and hydroxide phases. In conclusion, this study shows that anaerobic wet-dry cycling with Fe-Ni phosphide minerals in slightly acidic pool could be a feasible method for peptide polymerization in prebiotic conditions. Future studies should focus on analyzing P-compounds in the solution and exploring the mineral’s catalytic role in varied prebiotic environments. These findings suggest schreibersite could have significantly contributed to AA polymerization in early Earth’s hydrothermal pools, with implications for prebiotic chemistry under oxygen-free conditions such as the early Earth.