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.