Using “artificial photosynthesis” scientists at UC Riverside and the University of Delaware have devised a way for plants to grow in complete darkness and make edible plants in the dark. The researchers grew the plants in complete darkness in an “acetate” medium that replaces organic photosynthesis.
They used a two-step electrocatalytic process to convert carbon dioxide, electricity and water into acetate. Food-producing plants are then consumed to grow this acetate. Interestingly, if combined with solar power panels, the system could increase the conversion efficiency of sunlight by up to 18 times compared to organic photosynthesis in some foods.
The researchers used an electrolyzer to convert raw materials such as carbon dioxide into acetate. Its production was adapted to support the growth of food-producing plants by increasing the amount of acetate produced and reducing the amount of salt produced as a byproduct.
According to the researchers, this resulted in some of the highest levels of acetate ever produced in the electrolyzer. “Using a state-of-the-art two-step tandem CO2 electrolysis setup developed in our laboratory, we were able to achieve a high selectivity towards acetate that cannot be accessed through conventional CO2 electrolysis routes,” said corresponding author Fang Xiao said, the University of Delaware, in a press statement.
In experiments, the scientists demonstrated that this technique could be used to grow a wide variety of food-producing organisms in the dark, including mushroom-producing green algae, yeast and fungal mycelium. According to a research article about the study published in Nature Food, producing algae with this technique is four times more energy efficient than growing it with photosynthesis. The peer-reviewed article also noted that yeast production is typically 18 times more energy-efficient than farming using sugar extracted from corn.
The researchers also tested the potential of using this technology to grow cowpea, tomato, tobacco, rice, canola and green peas. All plants were able to utilize carbon from the acetate medium when cultivated in the dark.
Artificial photosynthesis by removing the dependence on the sun has opened up the possibilities of growing food in the difficult conditions we could see in the future due to climate change. Potentially, droughts, floods and low land availability would be less of a threat to global food security if crops could be grown in such controlled and efficient environments.