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Microbial electrosynthesis (MES) systems can store renewable energy and CO 2 in many-carbon molecules inaccessible to abiotic electrochemistry. Here, we develop a multiphysics model to investigate the fundamental and practical limits of MES enabled by direct electron uptake and we identify organisms in which this biotechnological CO 2 -fixation str...
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... /2020 electrons to energy carrier regeneration and therefore carbon fixation (Tables S1 and S2). For microbes using the Calvin-Benson-Bassham (CBB) cycle, aerobic respiration uses only 23.67 electrons per pyruvate molecule, while anaerobic nitrate respiration requires 61.25 electrons for the equivalent reaction. ...Context 2
... we have identified several microbial chassis that have potential as industrial MES strains (Table 1) and outlined a series of Technology Readiness Levels (TRLs) to evaluate industrial relevance of microbial catalysts for MES (Table S7). Beyond the genetic modules that enable electroautotrophy, additional factors constrain the productivity achievable by a given organism. ...Context 3
... use these regeneration mechanisms to determine the stoichiometry (number of reduced molecules produced per number of electrons consumed) for aerobic or anaerobic nitrate respiration (Table S1). Because carbon fixation pathways have different energy carrier requirements, we also derive the overall stoichiometry for CO2 reduction to pyruvic acid (pyruvate) ( CC-BY-NC 4.0 International license available under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. ...Similar publications
The use of the plant Chrysopogon zizanioides (vetiver), able to develop under adverse conditions while removing a great number of pollutants, in constructed wetlands (CWs) is widely reported. Regarding the biological trickling filters (BTFs), the selection of the media is one of the most important factors in its performance. We investigated whether...
Citations
... Light-independent, lithoautotrophy can fix carbon by relying on chemically provided reducing power. On Mars, this could either directly be electricity through microbial electrosynthesis in bio-electrochemical systems (Moscoviz et al., 2016;Abel et al., 2020;Chen et al., 2020a), or indirectly by means of hydrogen or (organoautotrophically) formate, both of which can also be generated electrochemically (Kracke et al., 2020;Abel and Clark, 2021). Use of other electron donors like, e.g., sulphide, sulphur and iron (II) is theoretically possible, but technically less feasible (crustal materials from Mars are in principle able to support lithotrophic growth (Milojevic et al., 2021), but mining and purifying these in quantities that could support biotechnological processes is likely not viable). ...
Various microbial systems have been explored for their applicability to in-situ resource utilisation (ISRU) on Mars and suitability to leverage Martian resources and convert them into useful chemical products. Considering only fully bio-based solutions, two approaches can be distinguished, which comes down to the form of carbon that is being utilized: (a) the deployment of specialised species that can directly convert inorganic carbon (atmospheric CO2) into a target compound or (b) a two-step process that relies on independent fixation of carbon and the subsequent conversion of biomass and/or complex substrates into a target compound. Due to the great variety of microbial metabolism, especially in conjunction with chemical support-processes, a definite classification is often difficult. This can be expanded to the forms of nitrogen and energy that are available as input for a biomanufacturing platform. To provide a perspective on microbial cell factories that may be suitable for Space Systems Bioengineering, a high-level comparison of different approaches is conducted, specifically regarding advantages that may help to extend an early human foothold on the red planet.
A crewed mission to and from Mars may include an exciting array of enabling biotechnologies that leverage inherent mass, power, and volume advantages over traditional abiotic approaches. In this perspective, we articulate the scientific and engineering goals and constraints, along with example systems, that guide the design of a surface biomanufactory. Extending past arguments for exploiting stand-alone elements of biology, we argue for an integrated biomanufacturing plant replete with modules for microbial in situ resource utilization, production, and recycling of food, pharmaceuticals, and biomaterials required for sustaining future intrepid astronauts. We also discuss aspirational technology trends in each of these target areas in the context of human and robotic exploration missions.
