Artificial Photosynthesis Allows Plants to Grow in Darknesss: Can It Be Used on Terraforming Mars?

Research on developing artificial photosynthesis for growing plants is underway. This innovation can increase the energy efficiency of food production. The entire planet is included in the scope, and one day perhaps even the red planet.

For millions of years, plants have used photosynthesis to transform carbon dioxide, water, and solar energy into plant biomass and food. Only about 1% of the energy from sunlight reaches the plant during this process, which is very inefficient. Artificial photosynthesis has been developed by scientists at the Universities of California's Riverside and Delaware to completely replace the need for biological photosynthesis. This will also enable the production of food without the use of sunlight.

Acetate, Photosynthesis, and Energy Efficiency

The new study produces acetate, the primary constituent of vinegar, from electricity, carbon dioxide, and water using a two-step electrocatalytic process. Then, in the dark, organisms that produce food consume acetate. This hybrid organic-inorganic system could improve the conversion efficiency of sunlight into food, up to 18 times more efficient for some foods, when combined with solar panels to generate electricity to power the electrocatalysis.

Robert Jinkerson, the corresponding author of the research and a UC Riverside assistant professor of chemical and environmental engineering, said that with their strategy, the team aimed to discover a new approach to food production that could surpass the restrictions typically placed by biological photosynthesis.

For growing plants, the production of the electrolyzer was maximized to support the growth of food-producing organisms. The highest levels of acetate ever produced through an electrolyzer to date were achieved by increasing the amount of acetate generated while lowering the amount of salt used.

Feng Jiao, another corresponding author at the University of Delaware, explained that they achieved a high selectivity towards acetate using a cutting-edge two-step tandem CO2 electrolysis setup they developed in their lab. This selectivity is not possible using traditional CO2 electrolysis methods.

Experiments revealed that a variety of food-producing organisms, including yeast, green algae, and fungal mycelium that produces mushrooms, can be grown in the dark directly on the acetate-rich electrolyzer output. With this technology, growing algae is roughly four times more energy-efficient than growing it with conventional photosynthesis. Production of yeast uses about 18 times less energy than conventional methods, which typically use sugar from corn.

Elizabeth Hann, a co-lead author for the study and a doctoral candidate in the Jinkerson Lab, stated that without any assistance from biological photosynthesis, they were able to grow organisms that could produce food. She went on to say that these organisms are typically grown on plant-based sugars or petroleum-derived ingredients, which are byproducts of biological photosynthesis that occurred millions of years ago. Compared to food production that depends on biological photosynthesis, this technology is a more effective way to convert solar energy into food.

The team also looked into whether this technology could be used to grow crops. When grown in the dark, cowpea, rice, tomato, canola, tobacco, and green pea were all able to use carbon from acetate.

Marcus Harland-Dunaway, a co-lead author for the study and a doctoral candidate in the Jinkerson Lab, said that acetate could be incorporated by a variety of crops into the essential molecular building blocks required for an organism to develop and flourish. The team is currently working on breeding and engineering techniques that could allow them to grow crops with acetate as an additional energy source to increase crop yields.

Artificial photosynthesis makes it possible to grow food under the more challenging conditions brought on by anthropogenic climate change by releasing agriculture from its total reliance on the sun.

Effects on Food Production

Jinkerson pointed out that if crops for humans and animals grew in less resource-intensive, controlled environments, drought, floods, and decreased land availability would be less of a threat to global food security. Additionally, crops could be grown in urban areas and other regions that are currently unsuitable for agriculture, even providing food for future space explorers.

The use of artificial photosynthesis techniques to produce food, according to Jinkerson, may represent a paradigm shift in the way people are fed. As food production becomes more efficient, less land is required, reducing the environmental impact of agriculture. Additionally, the improved energy efficiency may make it possible to feed a larger crew while using fewer resources for agriculture in non-traditional environments, such as space.

This method of growing plants for food production was entered into the competition NASA Deep Space Food Challenge, to which the concept emerged as the winner for Phase I. The Deep Space Food Challenge is an international competition where teams compete for cash prizes to develop novel and game-changing food technologies that need few inputs and produce the safest, nourishing, and appetizing food possible for extended space missions.

Martha Orozco-Cárdenas, a co-author of the study and the director of the UC Riverside Plant Transformation Research Center, expressed optimism that in the future it may be possible to have vessels that can grow tomato plants in the dark on Mars, greatly simplifying future Martians' lives.