We have a much to thank photosynthesis for. Our whole existence, for a start. About 3 billion years ago, a group of microbes called cyanobacteria developed a way to convert light and water into energy and release oxygen in the process. These microbes would eventually flood our atmosphere with oxygen – transforming it from a toxic miasma of mostly nitrogen and carbon dioxide into the life-sustaining mixture we have today. It all – plants, humans, dogs, Netflix, ice – started with photosynthesis, more or less.
The same process is also right at the beginning of everything we eat. Plants use sunlight, water and carbon dioxide to grow, and then people either eat these plants directly, or after they have become part of an animal, a fungus or something else we like to munch on. All the energy that ends up in our bodies starts with sunlight that is captured by plants through photosynthesis. There’s just one small problem with this system – plants are actually pretty bad at converting sunlight into growth. According to some estimates, plants convert sunlight and carbon dioxide into new biomass with such a low efficiency as 1 pct.
Robert Jinkerson, a professor at the University of California, Riverside, looked at the lack of efficiency of photosynthesis and saw a technical problem. If we can squeeze more energy out of every square inch of sunlight, then we can reduce the total amount of soil we need to grow food. “Our ultimate goal is to change the way we think about how to produce crops and agriculture,” Jinkerson says. “If we can be more efficient with the land needed to produce the food needed for humanity, then we can return agricultural land to natural areas.”
One way to do this could be to grow crops in the dark by using electricity from solar panels, which are many times more efficient than plants at converting sunlight into energy. In a new scientific article published in the journal Nature foodJinkerson and his colleagues describe the use of solar panels to power one process called electrocatalysiswhich creates a liquid that algae, yeast and plants can use to grow instead of sunlight.
The researchers used solar panels to run a machine that converts carbon dioxide, electricity and water into acetate – a molecule that can be diluted in water and used to feed plants. They then fed this mixture to algae, yeasts, mushrooms and a variety of commonly grown plants, including cowpea, tomato, rapeseed and rice. The algae and yeast both grew quite efficiently on the acetate mixture, which is not exactly surprising since researchers already know that these species can eat acetate. What was more surprising was that the crop plants also consumed the acetate and grew even though they grew in complete darkness.
But before you close your tomato plants away in a closet, a warning. Jinkerson and his colleagues only knew that the plants ate the acetate because they dissolved them after growing for a while, and analyzed them to see if they contained carbon molecules from the acetate. But giving the plants enough acetate to grow on ended up being toxic to them – so even though plants can technically grow on acetate, they do not exactly thrive on it.