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Spark of Life: Role of Electrotrophy in the Emergence of Life. Life (Basel) 2023; 13:life13020356. [PMID: 36836714 PMCID: PMC9961546 DOI: 10.3390/life13020356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 01/20/2023] [Accepted: 01/25/2023] [Indexed: 01/31/2023] Open
Abstract
The emergence of life has been a subject of intensive research for decades. Different approaches and different environmental "cradles" have been studied, from space to the deep sea. Since the recent discovery of a natural electrical current through deep-sea hydrothermal vents, a new energy source is considered for the transition from inorganic to organic. This energy source (electron donor) is used by modern microorganisms via a new trophic type, called electrotrophy. In this review, we draw a parallel between this metabolism and a new theory for the emergence of life based on this electrical electron flow. Each step of the creation of life is revised in the new light of this prebiotic electrochemical context, going from the evaluation of similar electrical current during the Hadean, the CO2 electroreduction into a prebiotic primordial soup, the production of proto-membranes, the energetic system inspired of the nitrate reduction, the proton gradient, and the transition to a planktonic proto-cell. Finally, this theory is compared to the two other theories in hydrothermal context to assess its relevance and overcome the limitations of each. Many critical factors that were limiting each theory can be overcome given the effect of electrochemical reactions and the environmental changes produced.
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Screening for Hyperthermophilic Electrotrophs for the Microbial Electrosynthesis of Organic Compounds. Microorganisms 2022; 10:microorganisms10112249. [DOI: 10.3390/microorganisms10112249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 11/07/2022] [Accepted: 11/10/2022] [Indexed: 11/16/2022] Open
Abstract
Microbial electrosynthesis has recently emerged as a promising technology for the sustainable production of organic acids, bioplastics, or biofuels from electricity and CO2. However, the diversity of catalysts and metabolic pathways is limited to mainly mesophilic acetogens or methanogens. Here, eleven hyperthermophilic strains related to Archaeoglobales, Thermococcales, Aquificales, and methanogens were screened for microbial electrosynthesis. The strains were previously isolated from deep-sea hydrothermal vents, where a naturally occurring, spontaneous electrical current can serve as a source of energy for microbial metabolism. After 6 days of incubation in an electrochemical system, all strains showed current consumption, biofilm formation, and small organic molecule production relative to the control. Six selected strains were then incubated over a longer period of time. In the course of one month, a variety of metabolic intermediates of biotechnological relevance such as succinic acid and glycerol accumulated. The production rates and the promotion of specific metabolic pathways seemed to be influenced by the experimental conditions, such as the concentration of CO2 in the gas phase and electron acceptor limitation. Further work is necessary to clearly identify these effects to potentially be able to tune the microbial electrosynthesis of compounds of interest.
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Chaudhary S, Yadav S, Singh R, Sadhotra C, Patil SA. Extremophilic electroactive microorganisms: Promising biocatalysts for bioprocessing applications. BIORESOURCE TECHNOLOGY 2022; 347:126663. [PMID: 35017088 DOI: 10.1016/j.biortech.2021.126663] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2021] [Revised: 12/28/2021] [Accepted: 12/29/2021] [Indexed: 06/14/2023]
Abstract
Electroactive microorganisms (EAMs) use extracellular electron transfer (EET) processes to access insoluble electron donors or acceptors in cellular respiration. These are used in developing microbial electrochemical technologies (METs) for biosensing and bioelectronics applications and the valorization of liquid and gaseous wastes. EAMs from extreme environments can be useful to overcome the existing limitations of METs operated with non-extreme microorganisms. Studying extreme EAMs is also necessary to improve understanding of respiratory processes involving EET. This article first discusses the advantages of using extreme EAMs in METs and summarizes the diversity of EAMs from different extreme environments. It is followed by a detailed discussion on their use as biocatalysts in various bioprocessing applications via bioelectrochemical systems. Finally, the challenges associated with operating METs under extreme conditions and promising research opportunities on fundamental and applied aspects of extreme EAMs are presented.
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Affiliation(s)
- Srishti Chaudhary
- Department of Earth and Environmental Sciences, Indian Institute of Science Education and Research Mohali (IISER Mohali), Sector 81, S.A.S. Nagar, Manauli PO 140306, Punjab, India
| | - Sukrampal Yadav
- Department of Earth and Environmental Sciences, Indian Institute of Science Education and Research Mohali (IISER Mohali), Sector 81, S.A.S. Nagar, Manauli PO 140306, Punjab, India
| | - Ramandeep Singh
- Department of Earth and Environmental Sciences, Indian Institute of Science Education and Research Mohali (IISER Mohali), Sector 81, S.A.S. Nagar, Manauli PO 140306, Punjab, India
| | - Chetan Sadhotra
- Department of Earth and Environmental Sciences, Indian Institute of Science Education and Research Mohali (IISER Mohali), Sector 81, S.A.S. Nagar, Manauli PO 140306, Punjab, India
| | - Sunil A Patil
- Department of Earth and Environmental Sciences, Indian Institute of Science Education and Research Mohali (IISER Mohali), Sector 81, S.A.S. Nagar, Manauli PO 140306, Punjab, India.
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Pillot G, Amin Ali O, Davidson S, Shintu L, Combet-Blanc Y, Godfroy A, Bonin P, Liebgott PP. Evolution of Thermophilic Microbial Communities from a Deep-Sea Hydrothermal Chimney under Electrolithoautotrophic Conditions with Nitrate. Microorganisms 2021; 9:microorganisms9122475. [PMID: 34946077 PMCID: PMC8705573 DOI: 10.3390/microorganisms9122475] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/26/2021] [Accepted: 11/26/2021] [Indexed: 11/16/2022] Open
Abstract
Recent studies have shown the presence of an abiotic electrical current across the walls of deep-sea hydrothermal chimneys, allowing the growth of electroautotrophic microbial communities. To understand the role of the different phylogenetic groups and metabolisms involved, this study focused on electrotrophic enrichment with nitrate as electron acceptor. The biofilm density, community composition, production of organic compounds, and electrical consumption were monitored by FISH confocal microscopy, qPCR, metabarcoding, NMR, and potentiostat measurements. A statistical analysis by PCA showed the correlation between the different parameters (qPCR, organic compounds, and electron acceptors) in three distinct temporal phases. In our conditions, the Archaeoglobales have been shown to play a key role in the development of the community as the first colonizers on the cathode and the first producers of organic compounds, which are then used as an organic source by heterotrophs. Finally, through subcultures of the community, we showed the development of a greater biodiversity over time. This observed phenomenon could explain the biodiversity development in hydrothermal contexts, where energy sources are transient and unstable.
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Affiliation(s)
- Guillaume Pillot
- Aix Marseille Université, Université de Toulon, CNRS, IRD, MIO UM 110, 13288 Marseille, France; (G.P.); (O.A.A.); (S.D.); (Y.C.-B.); (P.B.)
| | - Oulfat Amin Ali
- Aix Marseille Université, Université de Toulon, CNRS, IRD, MIO UM 110, 13288 Marseille, France; (G.P.); (O.A.A.); (S.D.); (Y.C.-B.); (P.B.)
| | - Sylvain Davidson
- Aix Marseille Université, Université de Toulon, CNRS, IRD, MIO UM 110, 13288 Marseille, France; (G.P.); (O.A.A.); (S.D.); (Y.C.-B.); (P.B.)
| | - Laetitia Shintu
- Aix Marseille Université, CNRS Centrale Marseille, iSm2, 13284 Marseille, France;
| | - Yannick Combet-Blanc
- Aix Marseille Université, Université de Toulon, CNRS, IRD, MIO UM 110, 13288 Marseille, France; (G.P.); (O.A.A.); (S.D.); (Y.C.-B.); (P.B.)
| | - Anne Godfroy
- Laboratoire de Microbiologie des Environnements Extrêmes, Université de Bretagne Occidentale, CNRS, IFREMER, 29280 Plouzané, France;
| | - Patricia Bonin
- Aix Marseille Université, Université de Toulon, CNRS, IRD, MIO UM 110, 13288 Marseille, France; (G.P.); (O.A.A.); (S.D.); (Y.C.-B.); (P.B.)
| | - Pierre-Pol Liebgott
- Aix Marseille Université, Université de Toulon, CNRS, IRD, MIO UM 110, 13288 Marseille, France; (G.P.); (O.A.A.); (S.D.); (Y.C.-B.); (P.B.)
- Correspondence:
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