Photosynthesis, which is the process that sustains nearly all life on our planet, does not efficiently harness energy; in fact, only about 1% of the light energy a plant absorbs is transformed into chemical energy within the plant. A perspective paper published on October 23 in the Cell Press journal Joule discusses a bold new food production method called “electro-agriculture.” This method intends to substitute photosynthesis with a solar-driven chemical reaction that converts CO2 into an organic compound that specially engineered plants would “consume.” Researchers estimate that if all food in the US were cultivated using electro-agriculture, it could decrease the land required for farming by a staggering 94%. Additionally, this technique could facilitate food growth in outer space.
“If sunlight is no longer a requirement for plant growth, we can separate agriculture from its natural surroundings and cultivate food in indoor, controlled settings,” states Robert Jinkerson, a biological engineer at the University of California, Riverside, who is the corresponding author. “It’s time for agriculture to advance technologically, and conducting it in a controlled manner that isn’t dependent on nature is crucial for the future.”
Electro-agriculture envisions transforming agricultural lands into multi-story structures. Solar panels situated on these buildings would capture solar energy, powering a chemical reaction involving CO2 and water to create acetate—a molecule akin to acetic acid, the key ingredient in vinegar. This acetate would then serve as nourishment for plants grown hydroponically. The approach could also apply to cultivating other food-producing organisms, as mushrooms, yeast, and algae naturally utilize acetate.
“The primary goal of this innovative process is to enhance photosynthesis efficiency,” explains Feng Jiao, a senior author and electrochemist at Washington University in St. Louis. “Currently, we achieve around 4% efficiency, which is already four times better than photosynthesis. With this method, overall efficiency improves, leading to a smaller CO2 footprint in food production.”
To create plants capable of metabolizing acetate, researchers are leveraging a metabolic pathway that sprouts use to digest nutrients stored in their seeds. This pathway typically shuts down once the plants can perform photosynthesis, but reactivating it would allow them to use acetate for energy and carbon.
“We aim to reactivate this pathway in mature plants to awaken their original capacity to utilize acetate,” says Jinkerson. “It’s similar to lactose intolerance in humans—infants can digest lactose found in milk, but several people lose that ability as they age. The concept is quite alike, except it’s focused on plants.”
The research team is initially concentrating on tomatoes and lettuce but intends to progress towards energy-rich staple crops like cassava, sweet potatoes, and various grains in the future. So far, they have successfully modified plants to use acetate alongside photosynthesis, but their ultimate goal is to engineer plants that can derive all their energy solely from acetate, making them independent of light.
“For plants, we’re still in the development stages of enabling them to leverage acetate as their carbon source since they haven’t evolved in this way, but we are making strides,” notes Jinkerson. “Conversely, mushrooms, yeast, and algae can be cultivated using this method right now, so those applications could see commercial use first, with plant applications following later.”
The research team also plans to refine their acetate production technique, aiming for an even more efficient carbon-fixation process.
“This represents merely the first phase of our research, and we are hopeful that its efficiency and cost-effectiveness will significantly rise in the near future,” Jiao adds.
