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Mars Science

Researchers Grow Food Plants Without Sunlight (ucr.edu) 46

Photosynthesis "is very inefficient, with only about 1% of the energy found in sunlight ending up in the plant," according to a new announcement from the University of California, Riverside. But now scientists at the school and the University of Delaware "have found a way to bypass the need for biological photosynthesis altogether and create food independent of sunlight by using artificial photosynthesis." The research, published in Nature Food, uses a two-step electrocatalytic process to convert carbon dioxide, electricity, and water into acetate, the form of the main component of vinegar. Food-producing organisms then consume acetate in the dark to grow. Combined with solar panels to generate the electricity to power the electrocatalysis, this hybrid organic-inorganic system could increase the conversion efficiency of sunlight into food, up to 18 times more efficient for some foods.

"With our approach we sought to identify a new way of producing food that could break through the limits normally imposed by biological photosynthesis," said corresponding author Robert Jinkerson, a UC Riverside assistant professor of chemical and environmental engineering...

Experiments showed that a wide range of food-producing organisms can be grown in the dark directly on the acetate-rich electrolyzer output, including green algae, yeast, and fungal mycelium that produce mushrooms. Producing algae with this technology is approximately fourfold more energy efficient than growing it photosynthetically. Yeast production is about 18-fold more energy efficient than how it is typically cultivated using sugar extracted from corn. "We were able to grow food-producing organisms without any contributions from biological photosynthesis..." said Elizabeth Hann, a doctoral candidate in the Jinkerson Lab and co-lead author of the study. The potential for employing this technology to grow crop plants was also investigated. Cowpea, tomato, tobacco, rice, canola, and green pea were all able to utilize carbon from acetate when cultivated in the dark....

By liberating agriculture from complete dependence on the sun, artificial photosynthesis opens the door to countless possibilities for growing food under the increasingly difficult conditions imposed by anthropogenic climate change. Drought, floods, and reduced land availability would be less of a threat to global food security if crops for humans and animals grew in less resource-intensive, controlled environments. Crops could also be grown in cities and other areas currently unsuitable for agriculture, and even provide food for future space explorers.

"Using artificial photosynthesis approaches to produce food could be a paradigm shift for how we feed people," said corresponding author Robert Jinkerson, a UC Riverside assistant professor of chemical and environmental engineering. "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...."

"Imagine someday giant vessels growing tomato plants in the dark and on Mars — how much easier would that be for future Martians?" said co-author Martha Orozco-Cárdenas, director of the UC Riverside Plant Transformation Research Center.

Thans to Slashdot reader John.Banister for sharing the link!
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Researchers Grow Food Plants Without Sunlight

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  • "is very inefficient, with only about 1% of the energy found in sunlight ending up in the plant,"

    It's a good thing too, that foliage is green, not black like a solar cell - so the ground is not perpetually chilled.

    Interesting that plants can use acetate alone -- there are already acetate-based fertilizers:
    https://www.cultivacegrowth.co... [cultivacegrowth.com]

    • Fertilizer is largely made from fossil fuel that is the result of sunlight.
      • True. And fossil fuels are probably required for creating the solar panels, the electrolyser, and (critically) the concentrated CO2 gas input to the electrolyser. The factory won't grab it's CO2 from the air, will it? (Maybe it will, with additional infrastructure)

        Not saying this isn't useful research. It's just the researchers' 'dark-farming' vision is a bit too ...noir; for me anyway. :-)

        • by jonadab ( 583620 )
          > The factory won't grab it's CO2 from the air, will it?

          They'll probably buy it; I think it is normally collected in bulk from waste products (e.g., from ammonia production plants); this is markedly more efficient than distilling it from the atmosphere, since the starting concentration can be so much higher.

          Since the waste products in question would _otherwise_ likely just get released into the air, collecting the CO2 from the waste and selling it, does indeed effectively remove it from the air (until wh
      • by caseih ( 160668 ) on Sunday July 03, 2022 @11:18AM (#62669936)

        Except that whole classes of plants use bacteria to fix nitrogen from the air. No fossil fuel fertilizer whatsoever. If bacteria could be engineered to feed other kinds of food crop plants, that would eliminate the use of fossil fuels entirely for fertilizer production.

        There's still the issue of phosphate nutrients but that never was related to fossil fuels.

    • I wonder what the weed industry will make out of this. So much could be saved on electricity, plus it would be harder for the Tacklebrries to use thermal imaging to find your stuff.
  • by Anonymous Coward

    What could possibly go wrong...

    they mention tomatos.
    Will they still be red when ripe after being grown in the dark.
    Will they still end up with the same nutrients or will the plants slowly evolve to get rid of anything they no longer need since they're in the dark.

    • What could possibly go wrong...

      they mention tomatos.
      Will they still be red when ripe after being grown in the dark.
      Will they still end up with the same nutrients or will the plants slowly evolve to get rid of anything they no longer need since they're in the dark.

      d) Will they taste of acetate?

      • by gtall ( 79522 )

        They already taste like acetate, those red bulbs stores pass off as tomatoes. Canned taste better.

        • by piojo ( 995934 )

          Canned fruit is usually fresher than fresh. It can be picked when ripe and canned and heated within a short time. Whereas fresh fruit needs to be shipped to stores, so it is picked unripe, then stored cold until it's time to ripen (whether on its own or because of exposure to ethylene).

    • One step closer to triffids. Tomato plants are already carnivorous.

  • by fuzzyfuzzyfungus ( 1223518 ) on Sunday July 03, 2022 @10:38AM (#62669804) Journal
    This definitely seems like an interesting trick; but I'd be curious to know what sort of obnoxious issues would crop up if you attempted to scale it.

    In particular, anything that depends on bringing your own catalysts rather than letting the biology sort out its own enzymes can end up being a real pain, even if the catalysts have better nominal performance when factory fresh. According to their methods section; construction of the necessary anodes and cathodes required silver, copper, iridium oxide, and nickel-iron oxide nanoparticles; along with nanocarbon/teflon and titanium felt substrates; along with some stainless steel(gold plated in certain locations) structural elements.

    That's both something that sounds a trifle more expensive than what you'd pick up down at the garden supply store; and includes some materials that are reasonably robustly biocidal if their ions get loose and end up downstream with the plant life you are trying to sustain(both copper and silver ions, in particular, are pretty good at telling plants that their presence is unwanted).

    I don't doubt that throwing some process chemists at the problem could improve the situation vs. a pure benchtop job; but that's still a lot of comparatively expensive catalyst material and carefully prepared membranes with limited lifespans compared to just letting what are effectively replicator nanites construct acres of photosynthetic collectors for you.
    • Mold is the bane of amateur mycologists everywhere. I wouldn't want to depend on this on a deep space voyage.

    • You are correct about all of this... maybe. If you can fully automate the process then there is a chance this could make vertical farming efficient enough to be economically feasible.

  • > Researchers Grow Food Plants Without Sunlight
    > Combined with solar panels to generate the electricity to power the electrocatalysis

    It still required sunlight, just indirectly. I suppose they could generate electricity some other way. This is not going to be life sustaining.

  • Since the beginning of time, man has yearned to destroy the sun...

  • Eating Food From Plants Grown Without Sunlight Causes Cancer.

  • by Rosco P. Coltrane ( 209368 ) on Sunday July 03, 2022 @11:50AM (#62669990)

    Every marijunana grower knows you can grow a crop without any sunlight.

  • "....possibilities for growing food under the increasingly difficult conditions imposed by anthropogenic climate change. Drought, floods, and reduced land availability would be less of a threat to global food security if crops for humans and animals grew in less resource-intensive, controlled environments. "

    Wow. I hope their science is characterized by fewer begged questions, false assumptions, and borderline-religious dogma than that single quote.

  • by 93 Escort Wagon ( 326346 ) on Sunday July 03, 2022 @12:37PM (#62670042)

    This is very fundamental research. It's interesting technically, but all the "maybe someday" talk is what scientists use to get funding (and university PR publicity, nowadays). Most of this level of research never progresses to a useful stage.

    * The actual energy conversion in the plant is "up to 18 times" more efficient - for yeast. The paper doesn't list the conversion efficiency for the tested plants most people actually care about - tomatoes, peppers, etc. - so it's likely less efficient than photosynthesis. The big question is... how much less efficient? It's probably much, much worse.

    * They're using solar panels and growing the plants on Murashige / Skoog medium, using vitamins produced for cell culture experiments. Somehow I doubt their efficiency calculations for yeast (or anything else) are taking into account all the extra cost and energy use involved in the production of those products.

  • I don't know about you, but I find this story really dark.
    • I don't know about you, but I find this story really dark.

      It'll probably never affect your diet, but it may end up feeding livestock or be used to mitigate climate change...or boost crop production. At this point, it is fundamental research anyway. There are MANY steps between a lab discovery at the University of Delaware and products produced from it going into something you can actually buy on the shelves of a local store or even amazon.com.

      If you can make Algae absorb CO2 4x faster, I can see it both useful as livestock feed and a carbon capture technology

  • by az-saguaro ( 1231754 ) on Sunday July 03, 2022 @02:25PM (#62670248)

    Title of the original article is "A hybrid inorganic–biological artificial photosynthesis system for energy-efficient food production". The authors did just that, demonstrating a clever method of capturing energy into an organic carbon compound by non-biological and non-solar methods, then showing that growing plants or fungi can use that nutritional carbon, and that the energy capture economics was quite favorable. It was definitely a clever and well done project, and a nice paper.

    But, it is a big leap to imply that this would have value for food production. There is a key flaw or omission in the subsequent reporting or interpretation.

    "Nutrition" has three main components. Think of a bio-organism as a machine like a car. (1) Some nutritional elements provide structural materials, metal in the car, protein in animals, carbohydrates in plants. (2) Other nutritional elements like trace metals, vitamins, and other micro nutrients are the greases, glues, lubes, solders, and so on that provide for the function, maintenance, and repair of the working machinery. (3) The third group is the fuel needed to run the system, petroleum based carbon for the vehicles, and organified carbon for biosystems, in the form of sugars, alcohols, ketones, or whatever each taxon uses. Photosynthesis is the way things have evolved for plants to use solar energy to organify carbon which in turn becomes both fuel to run the show and chemical substrate upon which to build (via enzymes) other necessary chemicals such as amino acids and structural polymers.

    When plants photosynthesize, some of the organified carbon, containing sun energy, is used to fuel metabolic processes in the cells which can lead to divers additional chemicals, including things like vitamins that are essential to our human diets. Some of the organified carbon is used for structure in the form of cellulose. Some is stored as starches and oils in seeds and roots where a germinating new sprout can use that energy in the dark under-the-soil world where sun does not shine, enough stored energy to allow the sprout to reach the surface where sunlight photosynthesis can then take over and supply energy from there.

    In the experiment reported, the most that the process can do is grow fungi or leafy vegetables that would in turn make the micro-nutrients and vitamins that we need in our diet. That is not trivial, but the process cannot supply the energy component of food. Their process supplies energy to plants so that they can grow independent of solar energy, and as such, they can make use of the acetate for components 1 and 2 of their nutritional needs, but not component 3, the fuel reserves. It would make no sense to invest in a huge chemical factory to make the acetate off of their crazy expensive catalysts just to capture CO2 that plants already do well. The process they describe is thermodynamically and chemically efficient, but industrially and economically very inefficient I would guess. Let's say that you build a big manufacturing plant that covers 10 hectares. It creates acetate from CO2 at 18 times the thermodynamic efficiency of photosynthesis on chloroplasts. Meh. If you just grow grass or soy or whatever on those 10 hectares, you will capture more carbon by nature than in the factory. And, if you use the industrial acetate to feed plants hoping that they will then convert that to nutritional food starches, you then lose much of the efficiency of the chemical process. It would be better to just find a way to capture CO2 directly to sugars or alcohols that the human body can ingest.

    So, the process they describe might be worthwhile for a boy scout troop camping on the dark side of the moon where they need to get their vitamins from their Ronco grow-in-the-dark lettuce lab. But, that process cannot supply the calories needed to sustain a body for too long.

    And, don't forget, that even if the CO2 > acetate > plant growth cycle is supported, the plants using the acetate cannot make amino acids from that withou

  • Humph, could it be efficiently applied to carbon sequestration as well?
  • How do this solar panels work without sunlight?

  • For taste and nutritions it is usually important that the plant is growing slow, especially - see the last sentence - for tomatoes.

    OTOH, that might be a good solution for biofuels.

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