autotroph Archives - Astrobiology

Schematic illustration of the proposed biological approach to MarWan biomanufacturing -- q-bio.CB

Astronauts and Explorers, Biochemistry & Organic Chemistry, Genomics, Proteomics, Bioinformatics, Life Support Systems, Mars, Microbiology & Virology, Nanotechnology & SynBio, Space Life Science, Status Report

Weaving Life Into Regolith: Engineered Autotrophic-Heterotrophic Consortia For Autonomous Biofabrication From Granular Feedstocks

by Keith CowingMay 15, 2026May 15, 2026

Long-duration human missions to Mars will require autonomous systems capable of converting in situ resources into structural materials, tools, and functional components. More broadly, such systems represent a class of […]

Carbon-silicate cycle includes a carbon dioxide (CO2) dissolution in rainwater to form carbonic acid (H2CO3) that falls on land and oceans; b reaction of H2CO3 and silicate (SiO32-) to form silicon dioxide (SiO2) and carbonate (CO32-), which is sequestered into oceanic crust for further recycling to the mantle followed by release into the atmosphere through volcanic activity; and c regeneration of CO2 through reaction between SiO2 and CO32-. Carbon fixation includes (d) reduction of CO2 to methane (CH4) through (e) the production of H2 from H2O on the surface of iron sulfide minerals that serve as sources of dissolved ferrous ion (Fe2+), which is photochemically oxidized to ferric ions (Fe3+.) in water vapor. Carbon monoxide (CO) either reacts with (f) H2O for synthesis of formic acid (HCOOH) or g ammonia (NH3) for synthesis of formamide (HCONH2). Hydrogen cyanide (HCN) formation may occur through either h reaction between CH4 and NH3 or i reaction of CH3• and N• through free radical mechanism. j HCN further reacts with H2O to produce CO and NH3.that also is produced through (k) N2 fixation under high temperatures, both can be sequestered into the mantle; l NH3 photolysis by UV radiation gives rise to N2 and H2; m hydrothermal H2 production occurs through the H2O oxidation by Fe2+ into H2 used for N2 fixation in the atmosphere. In this figure, royalty-free mountain and meteorite images designed by Freepik platform (www.freepik.com) are used. -- Nature via PubMed (open access)

Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biophysics, Biosignatures & Paleobiology, Genomics, Proteomics, Bioinformatics, Habitable Zones, Origin & Evolution of Life, Status Report

Redox Chemistry Of Early Earth And The Origin Of Life

by Keith CowingApril 4, 2026April 4, 2026

Multiple controversial scenarios have been proposed explaining the emergence of life, both from environmental and chemical perspectives.

Summary of different extracellular electron transfer (EET) pathways. While it is common to classify EET based on the nature and function of the mediators, here the emphasis is on the means of electron transport. (A) Electrons are transported between cells via direct interspecies electron transfer (DIET) through (1) direct contact via conductive pili and/or nanowires, (2) conductive particles smaller than the cells (e.g., magnetite), and (3) conductive particles larger than the cells (e.g., activated carbon). (B) Electrons are exported from cells to the solid surface via outward EET through (1), (4) direct contact via redox-active proteins, (5) diffusive soluble electron shuttles, and (6) redox mediators or enzymes. (C) Electrons are taken up by cells from the solid surface via inward EET or extracellular electron uptake (EEU) through (1), (4)–(6). Asterisks denote that not the exact same mechanism is employed by outward EET and inward EET when redox-active proteins are involved. -- mLife

Biophysics, Biosignatures & Paleobiology, Extremeophiles and Extreme Environments, Habitable Zones, Magnetic Fields, Electromagnetism, bioelectricity,, Microbiology & Virology, Origin & Evolution of Life, Status Report

Current Understanding Of Electroautotrophy And Its Relevance In Astrobiology-related Research

by Keith CowingOctober 28, 2025October 28, 2025

Electroautotrophy—the use of extracellular electrons as the primary energy source for autotrophic metabolism—remains understudied compared to photoautotrophy and chemoautotrophy.

Reactive transport modeling results for (A) pipe-like (high xb) and (B) plume-like (low xb) fluid flow. The heat maps (C–F) show the predominant thermophile (M. jannaschii in red, D. thermolithotrophum in yellow, and M. thermolithotrophicus in blue) at varying xb values and subseafloor residence times below 85°C. H2 concentrations in and temperature of pure hydrothermal vent fluids were 300 µM and 214°C (C, D) and 950 µM and 330°C (E, F) representing Marker 33 and Marker 113, respectively, at Axial Seamount. The initial M. jannaschii:D. thermolithotrophum:M. thermolithotrophicus ratios were either 1:1:1 (C, E) or 1:1:100 (D, F). The conditions that best fit the field results for Marker 33 and Marker 113 are indicated with an F symbol in the heat map. via PubMed

Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biophysics, Biosignatures & Paleobiology, Extremeophiles and Extreme Environments, Genomics, Proteomics, Bioinformatics, Habitable Zones, Microbiology & Virology, Status Report

Non-thermodynamic Factors Affect Competition Between Thermophilic Chemolithoautotrophs From Deep-sea Hydrothermal Vents

by Keith CowingSeptember 25, 2024September 25, 2024

Various environmental factors, including H2 availability, metabolic tradeoffs, optimal growth temperature, stochasticity, and hydrology, were examined to determine if they affect microbial competition between three autotrophic thermophiles.