scholarly journals Thioester synthesis through geoelectrochemical CO2 fixation on Ni sulfides

2020 ◽  
Author(s):  
Norio Kitadai ◽  
Ryuhei Nakamura ◽  
Masahiro Yamamoto ◽  
Satoshi Okada ◽  
Wataru Takahagi ◽  
...  
Keyword(s):  
Origin Of Life ◽  
Room Temperature ◽  
Nickel Sulfide ◽  
Co2 Fixation ◽  
Hydrothermal Systems ◽  
Co Dehydrogenase ◽  
Enzymatic Process ◽  
Electrochemical Condition ◽  
Co2 Electroreduction

Abstract Thioester synthesis by CO dehydrogenase/acetyl-CoA synthase is among the most ancient autotrophic metabolisms. Although the preceding prebiotic CO2 fixation routes to thioesters are often suggested, none has any experimentally supported evidence. Here we demonstrate that, under an electrochemical condition realizable in early ocean hydrothermal systems, nickel sulfide (NiS) gradually reduces to Ni0, while accumulating surface-bound CO due to CO2 electroreduction. The resultant partially reduced NiS facilitates thioester (S-methyl thioacetate) formation from CO and methanethiol even at room temperature and neutral pH. This thioester formation can further be enhanced up to a selectivity of 56% by NiS coprecipitating with FeS or CoS. Considering the central role of Ni in the enzymatic process mentioned above, our demonstrated thioester synthesis with the partially reduced NiS could have a direct implication to the autotrophic origin of life.

scholarly journals Thioester Synthesis through Geoelectrochemical CO2 Fixation on Ni Sulfides

2020 ◽  
Author(s):  
Norio Kitadai ◽  
Ryuhei Nakamura ◽  
Masahiro Yamamoto ◽  
Satoshi Okada ◽  
Wataru Takahagi ◽  
...  
Keyword(s):  
Origin Of Life ◽  
Room Temperature ◽  
Nickel Sulfide ◽  
Co2 Fixation ◽  
Hydrothermal Systems ◽  
Co Dehydrogenase ◽  
Enzymatic Process ◽  
Electrochemical Condition ◽  
Co2 Electroreduction

Thioester synthesis by CO dehydrogenase/acetyl-CoA synthase is among the most ancient autotrophic metabolisms. Although the preceding prebiotic CO2 fixation routes to thioesters are often suggested, none has any experimentally supported evidence. Here we demonstrate that, under an electrochemical condition realizable in early ocean hydrothermal systems, nickel sulfide (NiS) gradually reduces to Ni0, while accumulating surface-bound CO due to CO2 electroreduction. The resultant partially reduced NiS facilitates thioester (S-methyl thioacetate) formation from CO and methanethiol even at room temperature and neutral pH. This thioester formation can further be enhanced up to a selectivity of 56% by NiS coprecipitating with FeS or CoS. Considering the central role of Ni in the enzymatic process mentioned above, our demonstrated thioester synthesis with the partially reduced NiS could have a direct implication to the autotrophic origin of life.<br>

scholarly journals Thioester Synthesis through Geoelectrochemical CO2 Fixation on Ni Sulfides

2020 ◽  
Author(s):  
Norio Kitadai ◽  
Ryuhei Nakamura ◽  
Masahiro Yamamoto ◽  
Satoshi Okada ◽  
Wataru Takahagi ◽  
...  
Keyword(s):  
Origin Of Life ◽  
Room Temperature ◽  
Nickel Sulfide ◽  
Co2 Fixation ◽  
Hydrothermal Systems ◽  
Co Dehydrogenase ◽  
Enzymatic Process ◽  
Electrochemical Condition ◽  
Co2 Electroreduction

Thioester synthesis by CO dehydrogenase/acetyl-CoA synthase is among the most ancient autotrophic metabolisms. Although the preceding prebiotic CO2 fixation routes to thioesters are often suggested, none has any experimentally supported evidence. Here we demonstrate that, under an electrochemical condition realizable in early ocean hydrothermal systems, nickel sulfide (NiS) gradually reduces to Ni0, while accumulating surface-bound CO due to CO2 electroreduction. The resultant partially reduced NiS facilitates thioester (S-methyl thioacetate) formation from CO and methanethiol even at room temperature and neutral pH. This thioester formation can further be enhanced up to a selectivity of 56% by NiS coprecipitating with FeS or CoS. Considering the central role of Ni in the enzymatic process mentioned above, our demonstrated thioester synthesis with the partially reduced NiS could have a direct implication to the autotrophic origin of life.<br>

Thioester Synthesis by Geoelectrochemical CO2 Fixation on Ni Sulfides

2020 ◽  
Author(s):  
Norio Kitadai ◽  
Ruhei Nakamura ◽  
Masahiro Yamamoto ◽  
Satoshi Okada ◽  
Wataru Takahagi ◽  
...  
Keyword(s):  
Origin Of Life ◽  
Nickel Sulfide ◽  
Co2 Fixation ◽  
Hydrothermal Systems ◽  
Co Dehydrogenase ◽  
Enzymatic Process ◽  
Electrochemical Condition ◽  
Autotrophic Metabolism ◽  
Co2 Electroreduction

<i></i>Thioester synthesis via CO2 fixation by CO dehydrogenase/acetyl-CoA synthase is among the most ancient autotrophic metabolism often suggested to have a prebiotic root. Here we demonstrate that, under an electrochemical condition realizable in early ocean hydrothermal systems, nickel sulfide (NiS) gradually reduces to Ni0, thereby drastically enhancing its capability of driving nonenzymatic CO2 fixation. It catalyzes CO2 electroreduction to CO, concentrates CO on the surface Ni0 sites, and promotes CO condensation to a thioester in the presence of methanethiol. Even greater CO-to-thioester reaction efficiency is realized with NiS coprecipitating with FeS or CoS. Considering the central role of Ni in the enzymatic process mentioned above, our demonstrated thioester synthesis by the partially electroreduced NiS could have a direct implication to the autotrophic origin of life.<br>

scholarly journals Thioester synthesis through geoelectrochemical CO2 fixation on Ni sulfides

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Norio Kitadai ◽  
Ryuhei Nakamura ◽  
Masahiro Yamamoto ◽  
Satoshi Okada ◽  
Wataru Takahagi ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Origin Of Life ◽  
Deep Sea ◽  
Room Temperature ◽  
Nickel Sulfide ◽  
Co2 Fixation ◽  
Hydrothermal Systems ◽  
Standard Hydrogen Electrode ◽  
Hydrogen Electrode ◽  
The Origin Of Life

AbstractA 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 demonstrate that, under a simulated geoelectrochemical condition in primordial ocean hydrothermal systems (–0.6 to –1.0 V versus the standard hydrogen electrode), nickel sulfide (NiS) gradually reduces to Ni0, while accumulating surface-bound carbon monoxide (CO) due to 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.

Clustering-Triggered Efficient Room Temperature Phosphorescence from Nonconventional Luminophores

2019 ◽  
Author(s):  
Shuyuan Zheng ◽  
Taiping Hu ◽  
Xin Bin ◽  
Yunzhong Wang ◽  
Yuanping Yi ◽  
...  
Keyword(s):  
Room Temperature ◽  
High Efficiency ◽  
Spin Orbit Coupling ◽  
Design Rationale ◽  
Emission Mechanism ◽  
Room Temperature Phosphorescence ◽  
Electronic Interactions ◽  
Energy Gaps ◽  
Theoretical Results

Pure organic room temperature phosphorescence (RTP) and luminescence from nonconventional luminophores have gained increasing attention. However, it remains challenging to achieve efficient RTP from unorthodox luminophores, on account of the unsophisticated understanding of the emission mechanism. Here we propose a strategy to realize efficient RTP in nonconventional luminophores through incorporation of lone pairs together with clustering and effective electronic interactions. The former promotes spin-orbit coupling and boost the consequent intersystem crossing, whereas the latter narrows energy gaps and stabilizes the triplets, thus synergistically affording remarkable RTP. Experimental and theoretical results of urea and its derivatives verify the design rationale. Remarkably, RTP from thiourea solids with unprecedentedly high efficiency of up to 24.5% is obtained. Further control experiments testify the crucial role of through-space delocalization on the emission. These results would spur the future fabrication of nonconventional phosphors, and moreover should advance understanding of the underlying emission mechanism.<br>

Sewage sludge as a precursor of adsorbents/catalysts for environmental applications

2007 ◽  
Vol 2 (1) ◽  
Author(s):  
A. Ros ◽  
C. Canals-Batlle ◽  
M.A. Lillo-Ródenas ◽  
E. Fuente ◽  
M. A. Montes-Morán ◽  
...  
Keyword(s):  
Sewage Sludge ◽  
Room Temperature ◽  
Waste Water Treatment ◽  
Textural Properties ◽  
Active Species ◽  
Elemental Sulphur ◽  
Gaseous Emissions ◽  
Removal Experiments ◽  
Catalytically Active

This paper focuses on the valorisation of solid residues obtained from the thermal treatment of sewage sludge. In particular, sewage sludge samples were collected from two waste water treatment plants (WWTPs) with different sludge line basic operations. After drying, sludges were heated up to 700 °C in appropriate ovens under diluted air (gasification) and inert (pyrolysis) atmospheres. The solids obtained, as well as the dried (raw) sludges, were characterised to determine their textural properties and chemical composition, including the speciation of their inorganic fraction. All the materials under study were employed as adsorbents/catalysts in H2S removal experiments at room temperature. It was found that, depending on the particular sludge characteristics, outstanding results can be achieved both in terms of retention capacities and selectivity. Some of the solids outperform commercially available sorbents specially designed for gaseous emissions control. In these adsorbents/catalysts, H2S is selectively oxidised to elemental sulphur most likely due to the presence of inorganic, catalytically active species. The role of the carbon-enriched part on these solids is also remarked.

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