Green Hacking: Overclocking Photosynthesis

We think of hacking as bending technology to our will. But some systems are biological,  and we’re also starting to see more hacking in that area. This should excite science fiction fans used to with reading about cultures that work with biological tech, so maybe we’ll get there in the real world too.  Hacking farm crops and animals goes back centuries, although we are definitely getting better at it. A case in point: scientists have found a way to make photosynthesis better and this should lead to more productive crops.

We learned in school that plants use carbon dioxide and sunlight to create energy and produce oxygen. But no one explained to us exactly how that happened. It seems a protein called rubisco is what causes this to happen, but unfortunately it isn’t very picky. In addition to converting carbon (from carbon dioxide) into sugar, it also converts oxygen into toxic compounds called ROS (reactive oxygen species) that most plants then have to spend energy eliminating. Scientists estimate that if you could recover the calories lost in this process, you could feed an additional 200 million people worldwide at current production levels.

The video embedded below explains something of the photosynthesis mechanism found in different types of plant. Plants have to do something to counteract those toxic compounds, and in C3 plants that make up about 85% of species this takes some of the energy produced to combat. Maize, sorghum, and sugarcane are C4 plants which have a different way of handling photosynthesis that decreases toxic production naturally, and are correspondingly more productive. C3 plants have the added problem that in addition to the energy spent removing toxins about 20% of the sugar-producing mechanism gets diverted into making the toxin instead.

The layman explanation of the research is that a normal plant has a long path to remove the toxins —  photorespiration — and the scientists designed shorter pathways and developed genes to implement the hack before splicing them into tobacco plants and growing them in real fields for two years. The altered plants grew faster and taller along with producing 40% more biomass. Tobacco is very easy to work with but now they are turning to food crops to see if they can duplicate their success.

The research is sponsored in part by the Bill and Melinda Gates Foundation, and is part of a worldwide effort known as RIPE (Realizing Increased Photosynthetic Efficiency). While we might not get to a biology tech like Harry Harrison imagined in West of Eden, bioengineering can have big impacts. For example, read about how Norman Borlaug won the Nobel prize for saving about a billion people. Of course, there are also regular-tech ways of making farming more efficient.

 

29 thoughts on “Green Hacking: Overclocking Photosynthesis

  1. “This should excite science fiction fans used to with reading about cultures that work with biological tech, so maybe we’ll get there in the real world too. ”

    Depends upon the book. Not all are about the positive.

  2. I’ve got to be honest, my first reaction is “did no one wonder if there was a good reason why 85% of plants have evolved/been designed with an apparently sub-optimal thing like this. Perhaps there’s a reason we’ve not yet discovered?”

    1. It seems, based on the video, that the simpler C3 plants which have this issue have evolved in an environment with more CO2 available, so they didn’t need to be overly selective about oxygen.

      Besides, there can be too much of a good thing. If the plants don’t need to fix more glucose, why would they? The point of the plant is to reproduce, not necessarily grow big. “Fixing” the pathway just causes the plant version of morbid obesity. After all, the plant is limited in its metabolic rate by being a plant, so if it’s not growing big seeds like corn, there’s an excess of building materials and nowhere to put them.

        1. In a greenhouse, it’s common to augment CO2 concentrations, usually in the range of 1200-2000 PPM. The current atmospheric concentration of CO2 is approximately 405 PPM (depends on location/weather conditions). Many plants prefer 3-5 times our current, alarmingly high levels of CO2. They also like a warmer climate… Basically, if we just keep pumping CO2 into the atmosphere, we’ll accomplish the same, as messing with the genetics. Plants have been pulling CO2 out of the atmosphere forever, and most of that carbon goes into the ground with decay, and has been collecting as coal and oil. Our burning of carbon-based fuels, is really bring the carbon back into the environment, which every living thing depends on. Plants are the base of the food chain, everything else gets organic carbon from plants. Feed the plants, feed the people…

          My guess is that speeding up the photosynthesis, the plants will mature quicker, reproduce quicker, since that’s their only goal in survival.

          1. In greenhouses it works because they’re adding fertilizers and keeping the temperature and water levels optimal. While plants in the wild prefer higher CO2 environments, they’re limited by other factors.

            Most carbon from decaying plants actually ends up back in the air, because fungi and bacteria eat the organic matter. The oxygen catastrophe some hundreds of millions of years ago happened because trees evolved lignin and started producing all sorts of sticky resins, which were inedible to the microbes at the time, which protected the trees from rot and decay and allowed them to grow really huge – with the side effect of burying the carbon in the ground when they died without decomposing.

            Lignin is basically a polymer much like our plastics – when you put it in a hot retort at high pressure with water, out comes a liquid sludge that is pretty much exactly like oil, and has been used for an oil substitute during WW2.

          2. Actually, to a reasonable approximation, no carbon from plants accumulates in the soil or ground, whether as coal or peat. Peat formation requires special plants and special conditions which are quite rare when weighted by photosynthesis output. That carbon we’re adding just keeps going around and around.

          3. Forest fires used to bury great deals of CO2 in the ground, because micro-organisms can’t eat charcoal. The carbon ends up mixed with the soil and forms a carbon-rich sediment.

            Now that we’ve started controlling forest fires on a massive scale, that effect has diminished.

          4. Luke, sadly that it’s actually not true. There have been a number of studies over the last few decades into the value of biochar and forest fires in carbon sequestration, and so far it looks like biochar is neutral to slightly worse for carbon sinking than leaving things alive. E.g. https://www.scientificamerican.com/article/charcoal-in-burned-forests-no-way-to-store-carbon/ https://phys.org/news/2017-12-charcoal-co2-emissions-forest.html It’s a shame because I was very keen on biochar until I read those experiments.

          5. ” Our burning of carbon-based fuels, is really bring the carbon back into the environment, which every living thing depends on. ”

            That seems to imply that we can only raise the CO2 levels back up to levels where it has previously been. Since life thrived in those higher CO2 periods that sounds like a comforting thought.

            It is deceptively comforting.

            First, CO2 has always flowed in a cycle. Various processes bury it. Eventually it churns down to the molten layer eventually to be spit back out at a volcano somewhere. By digging it out of the ground millenia or even millions of years earlier than it would have come back to the atmosphere on it’s own we are changing the balance between how much is stored vs how much is active in the atmosphere. We could actually reach higher atmospheric CO2 levels than the world has seen previously this way.

            Second, when the world cycles between high and low atmospheric CO2 levels NATURALLY it requires deep time. We are making a transition that would normally take millions of years occur in just a few centuries. When it happens naturally life has time to adapt. It cannot adapt as fast as we are forcing it.

          6. Luke says:
            January 6, 2019 at 9:21 am
            “In greenhouses it works because they’re adding fertilizers and keeping the temperature and water levels optimal. While plants in the wild prefer higher CO2 environments, they’re limited by other factors.

            Most carbon from decaying plants actually ends up back in the air, because fungi and bacteria eat the organic matter.”

            In greenhouses, plants are in pots, with limited room for roots. It’s a closed environment, so, yeah, we have to provide for all the plant’s needs.

            Decay happens independently of bacteria. Cells breakdown on their own, then the feast begins. Bacteria don’t just feed on organic matter, and release CO2. Different bacteria, also produce various other gasses and compounds. Bacteria are also carbon-based life forms, short life span, they don’t turn into CO2 themselves. Bacteria don’t consume the entire corpse (plant or animal), just the portions they need to reproduce, leave a lot behind.

  3. Very Interesting! Now, put it down before it hurts someone. God-fearing or aetheist, there’s Mother Eath who took so long to get us to this point. A real-world test is needed, and a biodome we cab instantly super-incinerate without a nuke… somehow. Or we end up with a possibility of another GMO-BT Corn, Africanized Bee, or DDT. No, strike DDT, which can’t self-replicate. Bees don’t love corn but do visit it and the GMO-BT Corn IS bad for them. This “solution” carries with it, unsolved potential problems.

    1. Got some more info on how BT corn affects bees. The academic literature up to Nature Haven’t demonstrated any significant impacts to non target species, ie pests. The implication is actually the opposite, it increases biodiversity.
      The only concern with any merit I’ve found is contamination of organic crops, which only has a market impact and can be mitigated by trees planted to block wind and pollen between fields.

  4. Are we trying to save billions not born yet, or the billions on tue planet right now? If the latter this can be accomplished right in the now, the only thing getting in the way is people, no need to hack nature. In the end, hacking nature may just end up creating a Frankenstien.

    1. This.
      Let’s start by stopping mono-cultural cult, and try to bring back high vitamin fruits and vegetables.
      Roughly 30%* of food is let to root on the fields.
      Roughly 50%* of the rest is trashed during the transport, selling or just at home because we buy but don’t eat.
      So, let’s aim for better food, and more intelligent people instead of mountains of non-nutritional food that will be half trashed.
      * data varies from country to country and food product. Sea food is the most trashed, sugarish food, the less.

  5. plants prefer our climate warmer. they convert co2 to oxygen. globule warming is bad? melts ice, gives us too much water and oxygen. ok I get it! More people, producing garbage for land fills and littering, crowded freeways for commutators, and dictators for wars with bigger bombs.are we all a virus to mother earth? less is more. was China right?

    1. Plants are our most basic food on planet Earth. What”s best for plant growth, is what should be considered our normal environment. I know that’ll pissoff the folks that can’t live without ski resorts, beachfront property, or sunburn easy, but I would rather have food and fresh water. What are polar bears really good for? Coca Cola commercials, killing protected species of fur seals, knocking over eskimo trashcans? There is obviously an upper limit to the warming, this warming/cooling thing has been going on a long time, this isn’t a first. Wonder why we are given the impression it doesn’t end, just keeps warming. I don’t know if anybody else has noticed, how the IPCC only tells portions of the story, leaves out a lot of meaningful details. How often they forgot to mention, that some of those peer-reviewed papers, that provide key evidence, turned out to be wrong, years later…

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