Setting the ground for sustainable bioproduction in a Martian settlement

Abstract

To be sustainable, a settlement on Mars should be as independent of Earth as possible in terms of material resources. This independence may be reached with the help of biological systems: those could perform a wide range of functions with a low impact on the surroundings. However, biological systems would best rely on resources available on Mars – as recycling alone would mean that the amounts of available resources decrease over time – and most organisms cannot utilize raw Martian resources directly. Our team in Bremen is developing a system combining cyanobacteria, microbial electrochemical systems (MES) and higher plants to connect bioprocesses to materials available on Mars. In that system, selected cyanobacteria are used as primary producers as they could, it seems, be fed exclusively with materials available on site: water mined from the ground and atmosphere; carbon and nitrogen sourced from the atmosphere (as carbon dioxide and dinitrogen); and metal nutrients present in the local regolith. In addition to the direct production of various consumables, such as dioxygen and dietary proteins, cyanobacteria are here used to support the growth of secondary producers: namely, components of the MES. In the anodic compartment of the MES, organic compounds (from biomass and waste) are oxidized by exoelectrogenic microbes; in the cathodic compartment, electrotrophic microbes are used for the production of various compounds and for perchlorate remediation. Plants are tertiary producers, grown based on effluents from the cyanobacterium and MES modules, and used for the generation of essential resources such as food products, materials, pharmaceuticals and purified water. Our team currently focuses on (i) increasing the abilities of cyanobacteria to grow from Martian resources; (ii) processing their biomass as well as regolith with MES; (iii) integrating plants; and (iv) closing the production-consumption loop. As the foreseen system is versatile and modular, it can be adapted to other bioprocesses, thereby connecting them to local resources. We thus hope to lay the foundation for efficient and sustainable bioproduction on Mars. In that talk, we will present the overall concept and give an overview of the experimental results obtained so far.