Researchers have demonstrated that the filamentous fungus Penicillium simplicissimum can extract metals from a lunar regolith simulant, marking a significant step toward in situ resource utilization for future space missions. Published in Fungal Biology and Biotechnology, the study investigates the viability of biomining, a process that uses microorganisms to liberate metals from soil, as a sustainable alternative to energy-intensive traditional mining methods. The team specifically tested the fungus against EAC-1 A, a basaltic sandy silt simulant derived from the Siebengebirge volcanic field, which is currently being prepared for use in the European Lunar Exploration Laboratory (LUNA) facility in Cologne, Germany.
The central motivation for this research is the logistical challenge of transporting resources from Earth to the Moon. In future lunar exploration scenarios, raw materials such as regolith are widely available and represent a primary source for in situ resources. Samples recovered from Apollo missions reveal that lunar regolith contains a vast variety of metals, including iron, aluminium, and titanium, which are critical for the fabrication of equipment, construction materials, and power generation devices. Traditional mining approaches, such as molten salt electrolysis or the FFC process, are currently being studied but remain energetically intensive, making them less desirable for sustainable space exploration where energy efficiency is paramount.
Unlike bacteria, which have been tested for biomining aboard the International Space Station, filamentous fungi offer distinct advantages for space applications. Fungi are known for their role in bioleaching, a biomining method that mobilizes metals from ores into liquid culture medium by secreting organic acids such as citric and oxalic acid. These acids interact with minerals, breaking down chemical bonds and increasing metal solubility. Furthermore, fungal spores are dormant, resistant structures that can endure space radiation, making them highly suitable for transport and stowage during long-term space travel.
The experimental design began with biocompatibility tests to assess the fungus’s tolerance to the regolith simulant. The researchers monitored fungal colony area on agar plates supplemented with increasing concentrations of EAC-1 A, ranging from 0% to 60% by weight per volume. Initial results showed a decrease in colony area at the highest concentration on days 2 and 4, suggesting a stress response. However, by day 6, no significant difference was detected, indicating an adaptation of the fungus to the regolith over time. A second, longer incubation period of 9 days confirmed this adaptation, with colonies grown in 60% EAC-1 A showing a 20% increase in colony area compared to controls by day 9.
To understand the impact of the lunar environment, the team utilized a 2-D petri dish clinostat to simulate lunar gravity at 0.16 g. This device uses continuous rotation to prevent particle sedimentation, creating a functional simulation of altered gravity. Under these conditions, the fungus exhibited a 20% increase in colony area when grown without regolith compared to Earth gravity controls. However, the presence of 60% EAC-1 A regolith significantly reduced biomass and spore production under both gravitational regimes, with colonies in simulated lunar gravity showing 46% less biomass than those without regolith. These findings suggest that while the fungus can adapt to lunar gravity, the regolith itself imposes metabolic stress that affects growth parameters.
The core of the study involved bioleaching verification tests to determine the optimal conditions for metal extraction. The researchers compared full nutrient medium with a low nutrient medium, consisting of 20% Potato Dextrose Broth (PDB), and tested regolith concentrations of 30% and 60%. The results indicated that reducing nutrient availability improved bioleaching efficiency. In low nutrient medium, the fungus mobilized higher concentrations of iron, reaching 50 mg/L, compared to full medium cultures. The pH of the medium remained near neutral, around 7.5, during the bioleaching process, which challenges the assumption that bulk acidification is the primary driving mechanism for metal extraction in this specific fungal system.
After two weeks of incubation at room temperature, the leachate solutions were analyzed using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) to quantify the extracted metals. The analysis revealed the successful extraction of magnesium up to 159 mg/L, calcium at 151 mg/L, iron at 68 mg/L, aluminium at 32 mg/L, manganese at 3 mg/L, and traces of titanium at 0.02 mg/L. For comparison, a chemical leaching control group using only organic acids demonstrated successful but significantly lower metal mobilization, with magnesium at 15.5 mg/L and iron at 0.2 mg/L. This contrast highlights the superior efficiency of the fungal bioleaching process in maximizing metal release from the regolith particles.
The researchers then proceeded to recover the metals from the leachate through selective chemical precipitation. By adjusting the pH with sodium hydroxide and hydrochloric acid, they precipitated the metals into a powder form. The process yielded an average of 10 ± 3 g/L of metal oxide powder, which was predominantly white with brown-colored particles. This recovery rate is considered promising for potential industrial applications in space habitats, where the weight and volume of materials are critical constraints. The recovered powder was further characterized to confirm the presence and chemical nature of the metallic elements.
Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray Spectroscopy (EDS) were used to validate the metallic content of the recovered powder. The EDS analysis confirmed the presence of aluminium, calcium, magnesium, and iron, with aluminium showing high abundance. X-Ray Diffraction (XRD) analysis provided further insight into the crystallographic phases, revealing a spectrum mostly related to boehmite, an aluminium oxide hydroxide. Lower amounts of calcium carbonate and halite were also detected, along with possible traces of haematite and magnetite. The presence of boehmite suggests a reaction between the metal and secondary metabolites, potentially indicating complexolysis as a mechanism where chelating agents stabilize metal ions.
The study acknowledges several limitations and areas for future research. The specific driving mechanisms of P. simplicissimum-mediated leaching of EAC-1 A are not fully understood, as the peak accumulation of organic acids did not correlate with the minimum pH or maximum metal mobilization. This suggests that localized acidification at the hypha-mineral interface, biomechanical weathering, or the secretion of chelating compounds may play significant roles. Additionally, the size of the regolith particles strongly influences bioleaching efficiency, with smaller particles providing greater surface area for dissolution. Future work will need to optimize process parameters and understand the role of specific fungal metabolites in interacting with metal ions.
The implications of this research extend beyond simple metal extraction. The metals recovered, such as magnesium and aluminium, are highly attractive for space exploration due to their lightweight properties and utility in constructing vehicles and solar cells. Magnesium alloys, in particular, are known for their light structure, which is crucial for reducing fuel requirements in space missions. The ability to produce these materials in situ could help lunar habitats become independent from Earth resupply, creating avenues for commercial contributions and sustainable circular economies in space. The versatility of fungal biomining also allows for potential integration with other biotechnological processes, such as bioremediation of soil for agriculture or electronic waste recycling.
This study represents a foundational step in establishing fungal biomining as a viable In Situ Resource Utilization technology. The use of low nutrient media further supports the feasibility of this approach in resource-constrained environments.
The transition from laboratory flasks to actual space habitats will require further scaling and optimization. Future fungal bioleaching setups must accommodate both downscaling for miniaturized testing in Low Earth Orbit and upscaling for high-volume testing in ground-based facilities. The development of media with fewer nutrients and reduced regolith content, without compromising metal mobilization, is a critical next step. By bridging the gap between terrestrial biotechnology and space resource utilization, this research opens new possibilities for sustainable and cost-effective mining on the Moon, leveraging the natural metabolic capabilities of fungi to transform lunar soil into valuable industrial materials.
Subject of Research: Biomining of lunar regolith simulant EAC-1 A with the fungus Penicillium simplicissimum
Article Title: Biomining of lunar regolith simulant EAC-1 A with the fungus Penicillium simplicissimum
Article References: Figueira, J., Koch, S., Müller, D. W., Slawik, S., Cowley, A., Moeller, R., & Cortesão, M. (2025). Biomining of lunar regolith simulant EAC-1 A with the fungus Penicillium simplicissimum. Fungal Biology and Biotechnology, 12(1), Article 8. https://doi.org/10.1186/s40694-025-00201-z
Image Credits: AI Generated
DOI: 10.1186/s40694-025-00201-z
Keywords: Biomining, lunar, regolith, simulant, EAC-1, fungus, Penicillium, simplicissimum, scientific research
News Source: Roger Howard. (November 8, 2026). Fungus Extracts Metals from Lunar Soil Simulant in Lab Study. Scienmag.
