Artificial Photosynthesis can Produce Food in Absence of Sunlight: Study

According to a study conducted by the University of California, scientists have discovered a way to create food that is not dependent on sunlight by using artificial photosynthesis. A two-step electrocatalytic process converts carbon dioxide, electricity, and water into acetate.

In order to grow, food-producing organisms consume acetate in the dark. The hybrid organic-inorganic system has the potential to increase the efficiency of sunlight conversion into food by up to 18 times for some foods.

For millions of years, plants have evolved photosynthesis to convert water, carbon dioxide, and sunlight energy into plant biomass and the foods we eat. However, this process is inefficient, with only about 1% of the energy found in sunlight reaching the plant. Scientists at UC Riverside and the University of Delaware have discovered a way to create food without the need for biological photosynthesis by using artificial photosynthesis.

The study, which was published in the journal Nature Food, employs a two-step electrocatalytic process to convert carbon dioxide, electricity, and water into acetate, the main component of vinegar. In order to grow, food-producing organisms consume acetate in the dark. This hybrid organic-inorganic system, when combined with solar panels to generate the electricity to power the electrocatalysis, could increase the conversion efficiency of sunlight into food by up to 18 times for some foods.

"We sought to identify a new way of producing food that could break through the limits normally imposed by biological photosynthesis," said corresponding author Robert Jinkerson, an assistant professor of chemical and environmental engineering at UC Riverside.

The output of the electrolyzer was optimized to support the growth of food-producing organisms in order to integrate all of the system's components. Electrolyzers are electrical devices that convert raw materials such as carbon dioxide into useful molecules and products. The amount of acetate produced was increased while the amount of salt used was decreased, resulting in the most acetate ever produced in an electrolyzer to date.

"We were able to achieve a high selectivity towards acetate that cannot be accessed through conventional CO2 electrolysis routes using a state-of-the-art two-step tandem CO2 electrolysis setup developed in our laboratory," said corresponding author Feng Jiao of the University of Delaware.

Experiments revealed that a diverse range of food-producing organisms, including green algae, yeast, and fungal mycelium that produces mushrooms, can be grown in the dark directly on the acetate-rich electrolyzer output. This technology is approximately four times more energy efficient than growing algae photosynthetically. Yeast production is approximately 18- fold more energy-efficient than traditional methods of cultivation that use corn sugar.

"We were able to grow food-producing organisms in the absence of biological photosynthesis. These organisms are typically grown on sugars derived from plants or inputs derived from petroleum - a product of biological photosynthesis that occurred millions of years ago. This technology is a more efficient way of converting solar energy into food than biological photosynthesis," said Elizabeth Hann, a doctoral candidate in the Jinkerson Lab and co-lead author of the study.