Amino Acid Synthesis in a Supercritical Carbon Dioxide - Water System

Abstract

Mars is a CO2-abundant planet, whereas early Earth is thought to be also CO2-abundant. In addition, water was also discovered on Mars in 2008. From the facts and theory, we assumed that soda fountains were present on both planets, and this affected amino acid synthesis. Here, using a supercritical CO2/liquid H2O (10:1) system which mimicked crust soda fountains, we demonstrate production of amino acids from hydroxylamine (nitrogen source) and keto acids (oxylic acid sources). In this research, several amino acids were detected with an amino acid analyzer. Moreover, alanine polymers were detected with LC-MS. Our research lights up a new pathway in the study of life’s origin.

Discovery of supercritical carbon dioxide in a hydrothermal system

“…For example, it promotes glycerol carbonatation [44] and self-assembly in sugar-oil complex glasses [45]. It also promotes efficient production of formic acid [46,47] and even amino acids [47], suggesting that scCO 2 could play a significant role in triggering the origin of life on Earth.…”

Liquid and supercritical CO2 as an organic solvent in Hadean seafloor hydrothermal systems: implications for prebiotic chemical evolution

“…This suggests that L/SC-CO 2 pools can ultimately condense and store hydrophobic organics in hydrothermal systems. If L/SC-CO 2 pools establish dry conditions and promote the condensation of certain organics synthesized during hydrothermal circulation, they might be the efficient sites of dehydration synthesis and polymerization of L/SC-CO 2 -soluble organics in addition to other possible environments with L/SC-CO 2 (e.g., soda fountains and deep-reaching tectonic fault zones; Fujioka et al 2009;Schreiber et al 2012;Mayer et al 2015;2018). Furthermore, L/SC-CO 2 dissolves various types of organic molecules such as methanol and ascetic acid (Hyatt 1984), which not only induce various synthetic reactions but also elevate the solubilities and reaction rates of other organic molecules via the entrainer effect in certain cases (Jouyban et al 2005;Machmudah et al 2006).…”

“…Besides these two major hypotheses, there are a view that prebiotic chemical evolution might be facilitated by supercritical CO 2 (SC-CO 2 ) fluids (e.g., Fujioka et al 2009;Schreiber et al 2012). The critical point of CO 2 (T c = 31.1 °C; P c = 73.8 bar) is located among the mild temperature and pressure conditions, which frequently occurs in those of geologic environments.…”

“…Condensed CO 2 behaves as a nonpolar hydrophobic solvent in liquid and supercritical states (e.g., its solubility parameter is 14.6 MPa 1/2 at 40 °C and 20 MPa; Marcus 2018), and can be industrially used for polymer synthesis because of its high miscibility with many organic materials (e.g., Hyatt 1984;Cooper 2000;Shi et al 2015). Thus, as potential environments facilitating prebiotic chemical evolution, Fujioka et al (2009) assumed on-land soda fountains whereas Schreiber et al, (2012) proposed deep strikeslip fault zones in exposed proto-continents. However, partial pressure of CO 2 in atmosphere and ocean was probably reduced by water-rock reactions during formation process of primordial ocean to a level that L/SC-CO 2 is unstable (Ueda and Shibuya 2021).…”

Organic Analysis of Peridotite Rocks from the Ashadze and Logatchev Hydrothermal Sites

“…At these temperatures, combined with the pressures encountered at the hydrothermal sites, many compounds are in their supercritical state and peculiar chemistry can occur. In this IJMS issue on the Origin of Life, syntheses of amino acids in a mixture of supercritical CO 2 -liquid water (10:1) starting with hydroxylamine hydrochloride and pyruvic or glyoxylic acid are reported [ 52 ]. A hypothesis for the origin of the living systems could consequently be found at the bottom of the oceans, in ultramafic hosted hydrothermal systems, where tectonic plates separate to leave the upper mantle rock reacts with seawater to form hydrothermally altered peridotites and lead to the necessary molecules for life to emerge.…”