Scientists grow food in the dark with ‘artificial photosynthesis’

They used a two-step electrocatalytic process to convert carbon dioxide, electricity and water into acetate. The food-producing plants then consumed this acetate to grow. Interestingly, if combined with solar power panels, this system could increase the conversion efficiency of sunlight, up to 18 times more than biological photosynthesis in some foods.

The researchers used an electrolyser to convert raw materials like carbon dioxide into acetate. Its output was optimised to support the growth of food-producing plants by increasing the amount of acetate produced and decreasing 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 an electrolyser to date. “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 Feng Jiao, of the University of Delaware, in a press statement.

Plants grow in complete darkness in the acetate medium that replaces biological photosynthesis. (Image credit: UC Riverside)

In the experiments, scientists demonstrated that this technology could be used to grow a wide variety of food-producing organisms in the dark including green algae, yeast and fungal mycelium that produce mushrooms. According to the research article about the study published in Nature Food, producing algae with this technology is four times more energy-efficient than growing it with photosynthesis. The peer-reviewed article also says that the production of yeast is 18 times more energy-efficient than how it is typically cultivated using sugar extracted from corn.

The researchers also tested the potential to use this technology to grow Cowpea, tomato, tobacco, rice, canola and green pea. All plants were able to use the carbon from the acetate medium when cultivated in the dark.

By removing the dependence on the sun, artificial photosynthesis opens possibilities for growing food under the difficult conditions that we could see in the future due to climate change. Potentially, droughts, floods and reduced land availability would be less of a threat to global food security if crops could be grown in such controlled and efficient environments.