We’re all familiar with how plants use sunlight, water and carbon dioxide to create their own food through photosynthesis. But what if we could make that process more efficient to improve crop yields or biofuel production?
That’s what NC State University researcher Nathan Ennist hopes to do through his work on developing proteins that can perform artificial photosynthesis. Ennist, an assistant professor in the Department of Molecular and Structural Biochemistry and the Department of Physics and Astronomy, joined the faculty in 2025, bringing an interdisciplinary approach to his cutting-edge research that blends the study of light with the biochemistry of proteins.
We caught up with Ennist to learn about his innovative research and how developing a process for artificial photosynthesis could eventually open the door to new possibilities in agriculture.
What is the focus of your research?
I’m designing proteins that combine chlorophyll molecules, iron sulfur clusters, and other pigments and electron transfer co-factors to convert light into chemical energy. And then I want to put those designed proteins into plants or photosynthetic bacteria to try to improve biofuel production, nitrogen fixation or food crop production.
How did you get into this field of research?
I started doing protein design as a graduate student in a lab that was designing proteins sort of by hand. Then, as a postdoc, I was using computational methods for protein design and making more complex proteins that combined arrays of pigments. My Ph.D. lab was mostly respiration and photosynthesis, and my postdoc lab was strictly focused on protein design. Now, I’m trying to combine those two areas.
How does artificial photosynthesis differ from organic photosynthesis?
All natural photosynthetic reaction centers have a similar overall structure. This structure has been repurposed for all sorts of different types of photosynthesis.
The one we’re most familiar with, oxygenic photosynthesis, is found in plants, cyanobacteria and green algae and produces oxygen. But there are all kinds of other types of photosynthesis. There are all these different bacterial phyla that can do anoxygenic photosynthesis, where they use mostly near-infrared light to do either ATP production (a form of energy), sulfide oxidation, or other kinds of chemistry. But they’re all kind of using the same scaffold for all these different purposes.
When you look closely at the energetics of oxygenic photosynthesis, like from plants, what you find is that there’s a lot of wasted energy in some of the electron transfer steps. So, I think that we can re-engineer the electron transport chains in a way that would improve the overall efficiency.
How would artificial photosynthesis be more efficient, and how could you leverage that efficiency?
So if you’re growing algae for biofuels, if they can tap into the near-infrared light, then maybe you could reach higher cell densities and produce more algae that would be able to access light. As a result, we would generate more hydrogen or fix more carbon. And then the other thing is renewable nitrogen fixation. Most of our nitrogen for agricultural fertilizers comes from the Haber-Bosch process for making ammonia, which is responsible for something like 1% or 2% of global carbon emissions.
If we could couple light-driven charge separation to nitrogen fixation, we might be able to make ammonia renewably in order to produce fertilizer that has a low carbon footprint. We also might be able to make crops that produce more food, so you’d get more food per acre of land, which could help reduce the demand to clear new land for agriculture.
What are some examples of your current research projects?
We’re wrapping up a project that I started as a postdoc on a designed light-harvesting protein. We’re also starting to work on trying to find ways to use near-infrared light for water oxidation. Natural plant photosynthesis is limited to visible light, but anoxygenic phototrophs like purple bacteria can use near infrared light going up to 1,000 nanometers or even longer. I think that if we design a new protein that binds one of these purple bacterial pigments, we might be able to use really long-wavelength light to drive water oxidation. That means we’d be able to use water as a sacrificial electron donor in long-wavelength photosynthesis and produce chemical energy from water molecules and wavelengths of light that natural plants and green algae can’t use.
Once you develop proteins that conduct artificial photosynthesis, what’s the next step to apply that technology?
The long-term goal is to make proteins that can do artificial photosynthesis and self-assemble in living systems. We want to ultimately use a living system like that of a plant to express these designed proteins and assemble them inside the cell, and then break them down. That’s how we could eventually leverage these proteins to enhance photosynthesis for biofuel or crop production.