Researchers have found a way to completely bypass the need for biological photosynthesis and create food independent of sunlight using artificial photosynthesis. The study was published in the journal, Natural food.
The researchers used a two-step electrocatalytic process to convert carbon dioxide, electricity and water into acetate, the form of the main component of vinegar. Food-producing organisms then consume acetate in the dark to grow.
Combined with solar panels to generate the electricity needed for electrocatalysis, this hybrid organic-inorganic system could increase the efficiency of converting sunlight into food, up to 18 times more efficient for some foods.
“With our approach, we sought to identify a new way to produce food that could overcome the limits normally imposed by biological photosynthesis,” said corresponding author Robert Jinkerson, assistant professor of chemical and environmental engineering at UC Riverside. .
In order to integrate all system components together, the output of the electrolyser has been optimized to support the growth of food producing organisms. Electrolyzers are devices that use electricity to 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 reduced, resulting in the highest levels of acetate ever produced in an electrolyser to date.
“Using a state-of-the-art tandem CO2 electrolysis setup developed in our lab, we were able to achieve high selectivity towards acetate which is not accessible by the pathways of conventional CO2 electrolysis,” said corresponding author Feng Jiao at the University of Delaware.
Experiments have shown that a wide range of food-producing organisms can be cultured in the dark directly on the output of the acetate-rich electrolyzer, including green algae, yeasts and fungal mycelium which produce mushrooms. Producing algae with this technology is about four times more energy efficient than growing it using photosynthesis. Yeast production is about 18 times more energy efficient than the way it is typically grown using sugar extracted from corn.
“We were able to grow food-producing organisms without any input from biological photosynthesis. Typically, these organisms are grown on plant-derived sugars or petroleum-derived inputs – which is a product of biological photosynthesis that took place millions of years ago. The technology is a more efficient method of turning solar energy into food, compared to food production that relies on biological photosynthesis,” said Elizabeth Hann, PhD student at Jinkerson Lab and co-lead author of the study.
The possibility of using this technology to grow crops has also been investigated. Cowpea, tomato, tobacco, rice, canola, and green pea were all able to utilize acetate carbon when grown in the dark.
“We discovered that a wide range of cultures could take the acetate we provided and integrate it into the key molecular building blocks an organism needs to grow and thrive. Through breeding and engineering we are currently working on, we may be able to grow crops with acetate as an additional energy source to increase crop yields,” said Marcus Harland-Dunaway, a PhD student at the Jinkerson Lab and co- lead author of the study.
By freeing agriculture from total dependence on the sun, artificial photosynthesis opens the door to countless possibilities for growing food under the increasingly harsh conditions imposed by anthropogenic climate change. Drought, flooding and reduced land availability would be less of a threat to global food security if crops for humans and animals grew in less resource-intensive controlled environments. Crops could also be grown in cities and other areas currently unsuitable for agriculture, and even provide food for future space explorers.
“Using artificial photosynthesis approaches to produce food could be a paradigm shift in how we feed people. By increasing the efficiency of food production, less land is needed, which reduces the impact of farming on the environment.And for farming in non-traditional environments, such as in outer space, increased fuel efficiency could help feed more crew members with fewer inputs said Jinkerson.
This approach to food production was submitted to NASA’s Deep Space Food Challenge, where it won Phase I. The Deep Space Food Challenge is an international competition where prizes are awarded to teams to create new and innovative food technologies. breakthrough products that require minimal inputs and maximize safe, nutritious, and palatable food products for long-duration space missions.
“Imagine one day giant spaceships growing tomato plants in the dark and on Mars – would that be much easier for future Martians?” said co-author Martha Orozco-Cardenas, director of the UC Riverside Plant Transformation Research Center.