APPLICATION OF FILAMENTOUS FUNGI FOR SUSTAINABLE RESOURCE UTILIZATION IN SPACE HABITATS

Abstract

Despite having closed-loop life-support systems on the International Space Station (ISS), astronauts still depend on resources brought by cost-intensive resupply missions. To enhance the ISS's independence from Earth and prepare for long-term crewed missions to the Moon or Mars, there is an urgent need to develop self-sustained habitation, and a key concept for this is In situ resource utilization (ISRU), thus reducing mass, space and environmental constraints on space missions. One approach involves using microorganisms that can grow using nutrients available at the destination site, thereby reducing power demand and launch volume. Among all microorganisms suitable for this purpose, filamentous fungi play an important role. Penicillium simplicissimum, the model organism used in this work, is a mold-like fungus that promotes plant growth, produces a large number of important substances and has been demonstrated to extract metals (biomining) from lunar regolith. This project focused on developing a space-waste minimum resource set-up for P. simplicissimum cultivation to enable biotechnology both in space and on Earth. We identified seven space-waste components that are highly significant due to their anticipated presence in future space missions. Our approach involved creating various combinations of each component to identify their optimal minimal concentrations. For the final medium set-up, spore suspensions were inoculated in liquid cultures, having Potato Dextrose Broth (PDB) and a space-waste highconcentration (SWHC) medium as a control. Changes in the pellets' morphology were observed in the final Space-Waste Minimal (SWM) medium. However, the results indicate that despite this, the biomass and citric acid production remain unaffected, indicating the potential applicability of this medium in both Earth-based biotechnological processes and future long-term space missions. Moreover, in this work, we studied the suitability of the SWM medium for biomining processes. The results indicate that this medium is less efficient than the standardized PDB medium. Additionally, we evaluated the growth capability of P. simplicissimum under various space conditions, including in a Mars simulant regolith substrate supplemented with cyanobacteria, as an additional nutrient source, for ISRU approaches; under simulated microgravity conditions; and after exposure to cosmic ray ion irradiation (He, Fe, and Ar). The results show that P. simplicissimum exhibited resilience to all these space conditions.