Sometimes we assume that the natural way is the best way, or it doesn’t even occur to us to look for an alternative. Especially for the most basic things. But some scientists are questioning photosynthesis, the way plants use the sun’s energy for growth. Typical crop plants make use of as little as 1% of the sun’s energy they’re exposed to. Perhaps there could be a more efficient method.
The University of Delaware and University of California Riverside researchers have teamed up to figure out how to produce food through artificial photosynthesis, publishing their findings thus far last month in Nature Food. Robert Jinkerson at UC Riverside mixes engineering and botany. He and his group are experimenting with indoor agriculture, rather than old-school fields and sunlight. Jinkerson compares his approach with developments in medicine.
“Something that’s so important,” he said, as reported by Agri Pulse. “We take it into a lab, we make sure that we can produce as much as we need, we have very strict quality control.” Could this also be an upgrade to our food supply?
Related: Scientists get closer to artificial photosynthesis for renewable energy
The scientists at these two opposite-coast universities formed an alliance after Feng Jiao, a chemical and biomolecular engineering professor at the University of Delaware, gave a talk at UC Riverside. He mentioned using electrocatalysis to convert carbon dioxide to other products, including acetate. Jinkerson’s ears perked up at the mention of acetate because he suspected this salt was the key to growing food without sunlight. Seems he was on the right track.
But first, a quick review in case it’s been a while since you were in fifth grade. The Oxford dictionary defines photosynthesis as “the process by which green plants and some other organisms use sunlight to synthesize foods from carbon dioxide and water. Photosynthesis in plants generally involves the green pigment chlorophyll and generates oxygen as a byproduct.” In the lab, however, it’s different.
Acetate is key
Jinkerson, Jiao and their colleagues use a two-step carbon dioxide electrolyzer system, which produces the chemical compound acetate. Through the magic of electricity, an electrolyzer converts raw materials such as carbon dioxide into useful products and molecules. Acetate is commonly found in lots of stuff most of us have in our cupboards, from mustard to shampoo. It’s used as both an emulsifier to blend ingredients and a preservative to extend shelf life.
But Jinkerson and colleagues are using acetate to cultivate yeast and grow algae in the dark. Their electrolyzing experiments used a copper catalyst to convert 47% of carbon molecules from carbon dioxide into acetate. This concentrated acetate makes a futuristic plant food. The researchers tried it on rice, lettuce, green peas, cowpeas, peppers, canola, tomato, tobacco and mustard family member Arabidopsis.
And what was the result? When they powered the electrolyzer with an external solar cell, they found out that they could grow food with one-fourth the energy it usually takes to grow a crop the old-fashioned way. Algae grew four times faster than usual, and the yeast was a whopping 18 times more energy efficient than cultivating it using a sugar method. Lettuce also thrived.
However, there is a drawback. If there’s too much acetate in plants, the food will become toxic. So scientists still need to tweak their process before declaring independence from photosynthesis.
More food on less land
While the lab lacks the agrarian romance of rolling hills, snorting horses and crops swaying in the breeze, it solves many problems of our time. Climate change, invasive species, urbanization and land scarcity make it challenging to grow the necessary amount of food for a hungry world. And so food production is number one on these researchers’ minds.
“If we get rid of the need for sunlight, then we can grow multiple layers of crops at once, similar to the way mushrooms are grown and create a sort of food factory,” said Feng Jiao, as reported by Newswise.
Lab-grown food helps them conceptualize the growing process in a whole new way. “If I only care about the plant because it’s making food, then I can kind of reimagine that plant,” said Jinkerson.
If food could be grown from acetate, many nontraditional spaces could take the place of farms, from spaceships sprouting spinach to prisons packed with parsnips. Cities unsuitable for agriculture could suddenly grow vegetables.
“For countries that are prone to famine or maybe don’t have as much arable land, the technology could lower the burden of food growth if we can get the plants to grow wholly on acetate,” said Sean Overa, a University of Delaware chemical engineering doctoral student who was a co-author on the recently published paper.
Artificial photosynthesis is already being used in producing lab-grown meat. Not only can alternative meats cut greenhouse gas emissions by 96%, but water consumption also falls between 82 and 96%, depending on the animal being simulated. Plus, it decouples meat from murder.
While this new approach seems a bit weird, futuristic and sterile, we can compromise on our bucolic idea if it means a technology that will both neutralize carbon and provide food security.
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