In the quest for sustainable long-duration space missions, researchers are turning to an unlikely hero: mushrooms. Specifically, the sporeless oyster mushroom (Pleurotus ostreatus), a versatile fungus known for its ability to thrive on waste materials, is being explored as a potential food source aboard the International Space Station (ISS). This innovative approach, detailed in a recent study published in Gravitational and Space Research (Musci et al., 2025), not only addresses the challenge of food production in space but also offers a solution for recycling waste materials, reducing the need for resupply missions.
The Promise of Fungi in Space
Mushrooms have long been celebrated for their nutritional and medicinal properties. Rich in protein, vitamins, and minerals, they are also known for their immune-boosting and anti-inflammatory benefits (Muszyńska et al., 2018; Rizzo et al., 2021). Beyond their nutritional value, fungi are natural decomposers, capable of breaking down complex organic materials into simpler compounds. This makes them ideal candidates for bioregenerative life support systems (BLISS), which aim to create self-sustaining ecosystems in space.
The concept of growing fungi in space is not new. Experiments dating back to the 1930s have explored the effects of cosmic radiation and microgravity on fungal growth (Kern and Hock, 1993). More recently, fungi were included in NASA’s uncrewed Artemis I mission to study their adaptability in deep space (NASA, 2022). However, the focus has shifted from merely studying fungi to leveraging their potential for food production and waste recycling in space.
The ISS Waste Challenge
One of the critical challenges of long-duration space missions is waste management. Currently, waste on the ISS is compacted, stored, and either burned up in Earth’s atmosphere or returned to Earth (Caraccio & Hintze, 2013). This approach is unsustainable for missions beyond low-Earth orbit, where waste disposal options are limited. The accumulation of waste not only consumes valuable space but also poses risks to crew health and mission safety.
Enter the oyster mushroom. Researchers have identified several waste streams on the ISS—such as inedible plant biomass, cotton clothing, and food packaging plastics—that could serve as substrates for mushroom cultivation. By repurposing these materials, the need for additional food supplies is reduced, and waste is recycled into a valuable resource.
The Experiment: Growing Mushrooms on ISS Waste
In a recent study, researchers cultivated a sporeless strain of Pleurotus ostreatus (strain SPX) on seven different substrate recipes derived from ISS waste materials. These included cotton t-shirts, inedible plant biomass, and food packaging plastics, alongside traditional substrates like wheat straw and soy hulls. The goal was to assess the feasibility of growing mushrooms in a space-like environment with elevated carbon dioxide (CO₂) levels, similar to those on the ISS.
The results were promising. Mushrooms successfully grew on substrates containing cotton and inedible plant biomass, with the highest yields observed on a 70% cotton and 30% soy hull mixture. This combination outperformed traditional straw-based substrates, suggesting that cotton textiles could be a viable alternative for mushroom cultivation in space. Importantly, the mushrooms produced were found to be safe for consumption, with bacterial counts well below those found in commercially grown mushrooms (Rossouw and Korsten, 2017; Wang et al., 2017).
Challenges and Future Directions
While the study demonstrates the potential of mushrooms as a space crop, several challenges remain. Elevated CO₂ levels on the ISS, which can reach up to 3000 ppm, may affect mushroom morphology and yield. Additionally, the microgravity environment poses unique challenges for substrate preparation and sterilization. Future research will need to explore engineering solutions, such as controlled humidity and temperature systems, to optimise mushroom growth in space.
Another consideration is oxygen consumption. Unlike plants, which produce oxygen through photosynthesis, mushrooms respire like humans, potentially competing with astronauts for limited oxygen resources. However, intercropping mushrooms with plants could mitigate this issue, creating a balanced ecosystem that recycles both oxygen and CO₂ (Jung, 2017; Hamed et al., 2021).
Beyond Space: Implications for Earth
The implications of this research extend beyond space exploration. On Earth, oyster mushrooms are already used for mycoremediation—breaking down pollutants like heavy metals and petroleum waste—and mycofabrication, creating sustainable materials from fungal mycelium (El-Ramady et al., 2022; Attias et al., 2019). The ability to grow mushrooms on waste materials could revolutionise food production in resource-limited environments, such as disaster zones or areas with poor soil quality.
Moreover, the nutritional profile of oyster mushrooms—rich in protein, fibre, and essential vitamins—makes them an ideal candidate for addressing global food insecurity. As the world grapples with the challenges of climate change and population growth, fungi could play a pivotal role in creating sustainable food systems.
The cultivation of mushrooms on ISS waste streams represents a significant step towards sustainable space exploration. By turning waste into food, this approach not only reduces the logistical burden of resupply missions but also contributes to a closed-loop life support system. While challenges remain, the potential benefits—both in space and on Earth—are undeniable. As we look to the stars, fungi may well be the key to sustaining life beyond our planet.
References:
Musci, J., et al. (2025). Cultivating Sporeless Pleurotus ostreatus (Pearl Oyster) Mushrooms on Alternative Space-Based Substrates under Elevated Carbon Dioxide. Gravitational and Space Research, 13, 1–20.
Muszyńska, B., et al. (2018). Anti-inflammatory properties of edible mushrooms: A review. Food Chemistry, 243, 373–381.
Rizzo, G., et al. (2021). A review of mushrooms in human nutrition and health. Trends in Food Science & Technology, 117, 60–73.
Kern, V., & Hock, B. (1993). Fungi in space—literature survey on fungi used for space research. Microgravity Science and Technology, 6, 194–206.
NASA. (2022). Space Experiments: Investigating the roles of melanin and DNA repair on adaptation and survivability of fungi in Deep Space. NASA Science Investigations.
Caraccio, A.J., & Hintze, P. (2013). Trash-to-gas: Converting space trash into useful products. 43rd International Conference on Environmental Systems.
Rossouw, W., & Korsten, L. (2017). Cultivable microbiome of fresh white button mushrooms. Letters in Applied Microbiology, 64, 164–170.
Wang, Q., et al. (2017). UV-C Treatment maintains quality and delays senescence of oyster mushroom (Pleurotus ostreatus). Scientia Horticulturae, 225, 380–385.
Jung, G. (2017). Evaluating the methods, effects, economics of interplanting oyster mushrooms with vegetable crops. SARE.
Hamed, H.A., et al. (2021). Intercropping with Oyster Mushroom (Pleurotus columbinus) Enhances Main Crop Yield and Quality. IOP Conf. Ser.: Earth Environ. Sci., 690, 012028.
El-Ramady, H., et al. (2022). Green Biotechnology of Oyster Mushroom (Pleurotus ostreatus L): A Sustainable Strategy for Myco-Remediation and Bio-Fermentation. Sustainability, 14, 3667.
Attias, N., et al. (2019). Implementing bio-design tools to develop mycelium-based products. The Design Journal, 22, 1647–1657.