Scientists grow food in the dark with ‘artificial photosynthesis’

Scientists at the University of California Riverside and the University of Delaware have devised a way to grow plants in complete darkness and create food plants in the dark using “artificial photosynthesis.” The researchers grew plants in complete darkness in an ‘acetate’ medium that replaces biological 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 this system is combined with solar panels, it can increase the conversion efficiency of sunlight, by up to 18 times more than biological photosynthesis in some foods.

The researchers used an electrolyzer to convert raw materials such as carbon dioxide into acetate. Its production is optimized to support the growth of food-producing plants by increasing the amount of acetate produced and reducing the amount of salt produced as a by-product.

According to the researchers, this resulted in some of the highest levels of acetate ever produced in an electrolyzer to date. Corresponding author Feng Jiao said, “Using the latest two-step CO2 electrolysis setup developed in our laboratory, we were able to achieve high selectivity toward acetate that is not accessible by conventional CO2 electrolysis methods.” University of Delaware, in a press release.

Plants grow in complete darkness in an acetate medium that replaces biological photosynthesis. (Photo credit: University of California, Riverside)

In experiments, the scientists have shown that this technology can be used to grow a variety of food-producing organisms in the dark including green algae, yeast, and mycorrhizal fungi that produce mushrooms. According to a 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 yeast production is 18 times more energy efficient than the way it is typically grown using sugar extracted from corn.

The researchers also tested the possibility of using this technology to grow cowpeas, tomatoes, tobacco, rice, canola and green peas. All plants were able to use carbon from the acetate medium when grown in the dark.

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

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