Artificial photosynthesis lets plants grow efficiently in total darkness

2022-06-26

Scientists have improved on the natural process of photosynthesis, not only growing plants more efficiently, but doing so in the dark. This could expand agriculture to areas that don’t get enough sunlight, and even help feed future space explorers.

As you may recall from elementary school science class, photosynthesis is where plants absorb energy from sunlight and use it to create their own food from carbon dioxide and water. The process has helped plants – and by extension, life on Earth – thrive for billions of years, but that doesn’t mean it’s particularly efficient. In fact, only about three to six percent of the sunlight energy ends up in the plant.

Scientists have long tinkered with artificial photosynthesis, which is already much more efficient than the natural process. So-called artificial leaves can be used as an environmentally friendly way to make a range of products, including hydrogen fuel, syngas, methanol, plastic alternatives, and even drug molecules.

In this case, the resulting product was acetate, the main component of vinegar. This was then fed to plants as a carbon source, essentially bypassing natural photosynthesis. The team tested the technique on a series of crop plants and food-producing microbes, including yeast, green algae, fungal mycelium, cowpea, tomato, tobacco, rice, canola and green pea.

Using artificial photosynthesis approaches to produce food could be a paradigm shift for how we feed people

The scientists showed that the organisms could all be grown in an acetate medium in total darkness, and in some cases even more efficiently than in sunlight. The algae, for instance, was grown four times more efficiently, while yeast production was boosted an astonishing 18 times.

“We found that a wide range of crops could take the acetate we provided and build it into the major molecular building blocks an organism needs to grow and thrive,” said Marcus Harland-Dunaway, co-lead author of the study. “With some breeding and engineering that we are currently working on we might be able to grow crops with acetate as an extra energy source to boost crop yields.”

By uncoupling agriculture from the need for direct sunlight, the technique could enable food to be grown in regions with less ideal conditions, using less land. Crops could be grown in cities, and even in space or on other planets, an angle that earned the project a win in Phase I of NASA’s Deep Space Food Challenge.

“Using artificial photosynthesis approaches to produce food could be a paradigm shift for how we feed people,” said Robert Jinkerson, corresponding author of the study. “By increasing the efficiency of food production, less land is needed, lessening the impact agriculture has on the environment. And for agriculture in non-traditional environments, like outer space, the increased energy efficiency could help feed more crew members with less inputs.”

The research was published in the journal Nature Food.

New Atlas, 26 June 2022
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