Lab-grown lichens may aid future space manufacturing

Key Concepts

• Synthetic Lichens: Engineered microbial consortia mimicking the symbiotic relationship of natural lichens.
• Symbiosis: A biological interaction where two different organisms live in close physical association, benefiting each other.
• Cyanobacteria: Photosynthetic bacteria capable of converting CO2 and light into nutrients (sugars).
• Microbial Consortia: A group of two or more microbial populations that interact with each other.
• In-Situ Resource Utilization (ISRU): The practice of using local resources (like CO2 and light) to produce materials for space exploration.

Engineering Synthetic Lichens for Space Exploration

1. The Biological Foundation: Natural vs. Synthetic

Natural lichens are hardy, crusty organisms found on rocks and trees, functioning as a symbiotic partnership between a fungus and a photosynthetic partner (algae or cyanobacteria). In this relationship, the photosynthetic organism captures CO2 and light to produce nutrients, while the fungus provides structural protection.

Professor Rodrigo Ledesma Amaro and his team at Imperial College London are engineering synthetic lichens that replicate this efficiency but at significantly accelerated growth rates. Unlike natural lichens, which grow slowly, these lab-grown systems are optimized for industrial and space-based applications.

2. The Mechanism: The Cyanobacteria-Yeast Partnership

The synthetic system utilizes a two-part microbial framework:

• Cyanobacteria: Acts as the primary producer, converting carbon dioxide and light into sugars.
• Yeast: Acts as the consumer/processor, utilizing the sugars produced by the cyanobacteria to synthesize high-value products.

This pairing solves a critical logistical problem for space missions: the need for external nutrient supplies. By using cyanobacteria to create sugars from CO2 and light, the system becomes self-sustaining, eliminating the need to transport bulk sugar supplies from Earth.

3. Applications and Potential

The primary goal of this research is to support long-term space missions by producing essential materials on-site. The yeast component can be engineered to produce:

• Fuels: For propulsion or energy storage.
• Pharmaceuticals: Essential for crew health during long-duration missions.
• Food Ingredients: To supplement or provide nutrition for astronauts.

Professor Ledesma Amaro notes that there is "huge interest from space agencies" regarding these systems, as they represent a viable path toward sustainable life support and manufacturing in extraterrestrial environments.

4. Future Directions: Space Construction

Beyond chemical production, researchers are investigating the potential for using lichen-like microbial systems in space construction. While this remains in the "early experimental or conceptual stage," the concept involves using these biological systems to help build or reinforce structures in space, leveraging their ability to thrive in harsh environments and utilize available atmospheric or environmental resources.

Synthesis and Conclusion

The research at Imperial College London represents a shift from traditional manufacturing to biological engineering. By decoupling the production of essential chemicals from Earth-based supply chains, synthetic lichens offer a sustainable framework for space exploration. The core innovation lies in the metabolic coupling of cyanobacteria and yeast, which transforms abundant, low-energy inputs (CO2 and light) into complex, high-value outputs (fuels, food, and medicine). While currently in the laboratory phase, this technology holds significant promise for the future of autonomous, long-term human presence in space.