Photosynthesis evolved in plants over millions of years to turn water, carbon dioxide, and sunlight into plant biomass and the food we eat. Yet this natural process is inefficient, with only about 1% of sunlight energy captured by plants. Scientists from the University of California, Riverside, and the University of Delaware have demonstrated a path to bypass biological photosynthesis and grow food without sunlight through artificial photosynthesis.
Published in Nature Food, the research describes a two step electrocatalytic process that converts carbon dioxide, electricity, and water into acetate, the main component of vinegar. Food producing organisms then consume acetate in the dark to grow. When combined with solar panels that provide the electricity for the electrocatalysis, this organic inorganic hybrid system can boost the conversion of sunlight into food. For certain foods, efficiency gains reach up to eighteenfold.
Robert Jinkerson, assistant professor of chemical and environmental engineering at UC Riverside, explained that the goal was to discover a new way to produce food that overcomes the limits of biological photosynthesis.
To integrate all system components, the electrolyzer has been optimized to support the growth of food producing organisms. Electrolyzers use electricity to transform carbon dioxide into useful molecules. In this system, acetate production increased while salt use decreased, achieving the highest acetate levels ever created in an electrolyzer.
Feng Jiao of the Delaware campus noted that the two stage tandem CO2 electrolysis setup achieved high selectivity toward acetate, a product not readily accessible through conventional CO2 electrolysis routes.
Can be grown in the dark
Experiments show a wide range of food producing organisms can be grown directly at the acetate rich outlet in darkness. This includes green algae, yeasts, and fungal mycelia. Growing algae with this technology saves roughly four times more energy than traditional photosynthetic growth. Yeast production sees about an eighteenfold increase in energy efficiency compared to sugar based growth, typically derived from corn.
Researchers observed the organisms can flourish without any input from plant based photosynthesis. Traditionally these organisms rely on plant derived sugars or petroleum derived inputs that trace back to ancient photosynthesis. This technology provides a more efficient method of converting solar energy into food compared to biological photosynthesis.
Tomatoes, rice, or peas
The potential for growing crops using this acetate driven approach was also explored. When grown in the dark, crops such as black eyed peas, tomatoes, tobacco, rice, canola, and green peas can utilize acetate as a carbon source for growth.
We have found that a broad range of crops can convert the acetate supplied into the essential building blocks needed for growth and development. With ongoing breeding and engineering work, researchers aim to further boost crop yields and production of crops that can be grown from acetate.
Artificial photosynthesis offers a path to agriculture that does not depend entirely on sunlight, opening doors to farming in diverse environments and under challenging climate conditions. It could support food security as droughts, floods, and land constraints alter traditional farming.
Less land and less agricultural impact
Artificial photosynthesis to produce food may shift how people are fed by raising efficiency and reducing land use. In non traditional farming environments such as space, higher energy efficiency could help feed crews with fewer inputs.
The approach aligns with ambitious space food initiatives that seek technologies enabling safe, nutritious food production for extended missions. Co author Martha Orozco Cardenas, director of the UC Riverside Plant Transformation Research Center, envisions future scenarios where giant ships host dark grown tomato plants and even settlements on Mars.
Reference work appears in Nature Food: the linked article describes the experimental setup and findings.
Notes on the research indicate potential points for further exploration and validation across crop types and industrial scales.