Iron Sulfide-Catalyzed CO2 Reduction in Hot Springs – Nature Communications
Iron sulfides are well-known for their catalytic abilities across various reactions. Among them, greigite (Fe3S4) formed from mackinawite (FeS) has been identified as a crucial component in the origin of life. These electron-conducting structures are believed to have played essential roles in prebiotic chemistry by mimicking the [4Fe4S] clusters present in vital redox enzymes and electron carriers. Specifically, these structures have been associated with the ancient acetyl-CoA pathway and ferredoxins. Studies have shown that the last universal common ancestor (LUCA) likely depended on iron-sulfur cluster catalysis for various metabolic functions.
Focus on Terrestrial Hot Springs
While previous studies have primarily focused on iron sulfides in submarine alkaline hydrothermal vents as potential sites for the emergence of life, an alternative hypothesis suggests that life could have originated in terrestrial hot springs. These hot springs, fueled by geothermal activity and sunlight irradiation, could have provided environments conducive to CO2 reduction. The unique geochemical conditions and energy sources in terrestrial hot springs offer a different perspective on prebiotic chemistry compared to deep-sea hydrothermal vents.
Experimental Findings
New research has delved into the catalytic behavior of iron sulfides under simulated terrestrial hot spring conditions. By synthesizing FeS and various metal-doped FeS catalysts and subjecting them to CO2 reduction experiments, researchers observed the production of methanol (CH3OH). The kinetic analysis using gas chromatography revealed that FeS precipitates catalyze the reduction of CO2 to CH3OH, with Mn-doped FeS showing the most promising catalytic behavior. Further investigations into the mechanisms through experimental activation energy measurements, in situ diffuse reflectance infrared Fourier transform spectroscopy, and quantum mechanical modeling shed light on the intricate processes involved in gaseous CO2 reduction catalyzed by iron sulfides.
In conclusion, the study provides valuable insights into the potential role of iron sulfides in prebiotic carbon fixation in terrestrial hot spring environments, expanding our understanding of the diverse mechanisms that could have contributed to the origins of life on Earth.
