Japan Geoscience Union Meeting 2021

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[J] Oral

M (Multidisciplinary and Interdisciplinary) » M-IS Intersection

[M-IS14] Aqua planetology

Sat. Jun 5, 2021 1:45 PM - 3:15 PM Ch.02 (Zoom Room 02)

convener:Yasuhito Sekine(Earth-Life Science Insitute, Tokyo Institute of Technology), Takazo Shibuya(Japan Agency for Marine-Earth Science and Technology), Hidenori Genda(Earth-Life Science Institute, Tokyo Institute of Technology), Keisuke Fukushi(Institute of Nature & Environmental Technology, Kanazawa University), Chairperson:Yasuhito Sekine(Earth-Life Science Insitute, Tokyo Institute of Technology), Takazo Shibuya(Japan Agency for Marine-Earth Science and Technology), Keisuke Fukushi(Institute of Nature & Environmental Technology, Kanazawa University), Tomohiro Usui(Japan Aerospace Exploration Agency), Hidenori Genda(Earth-Life Science Institute, Tokyo Institute of Technology)

2:00 PM - 2:15 PM

[MIS14-08] Thioester synthesis through geoelectrochemical CO2 fixation on Ni and Mo sulfides.

*Norio Kitadai1 (1.Japan Agency for Marine-Earth Science and Technology)

Keywords:protometabolism

A prevailing scenario of the origin of life postulates thioesters as key intermediates in protometabolism, but there is no experimental support for the prebiotic CO2 fixation routes to thioesters. Here we introduce a two-steps thioester synthesis pathway starting from CO2 and H2S. First, we show MoS2-catalyzed efficient methanethiol production from CO2 and H2S in seawater in the presence of supercritical CO2. Then, simulating a geoelectrochemical condition in primordial ocean hydrothermal systems (–0.6 to –1.0 V versus the standard hydrogen electrode), we show that nickel sulfide (NiS) gradually reduces to Ni0 with the surface bound by carbon monoxide (CO) formed through CO2 electroreduction. The resultant partially reduced NiS realizes thioester (S-methyl thioacetate) formation from CO and methanethiol even at room temperature and neutral pH with the yield up to 35% based on CO. This thioester formation is not inhibited, or even improved, by 50:50 coprecipitation of NiS with FeS or CoS (the maximum yields; 27 or 56%, respectively). Such a simple thioester synthesis likely occurred in Hadean deep-sea vent environments, setting a stage for the autotrophic origin of life.