Inside a single beaker at Queen Mary University of London, sunlight is doing something that has eluded chemists for decades: growing living bacteria directly alongside the chemical reactions that feed them, without poisoning them in the process. Dr. Lin Su and his team have created an integrated solar reactor that combines an organic solar cell, semiconductor electrodes, two enzymes, and engineered E. coli bacteria in one unified system, turning CO₂ and water into living biomass using only sunlight—essentially mimicking photosynthesis without needing a plant, algae, or any photosynthetic organism in sight.
The work, published in the Journal of the American Chemical Society, matters because it cracks a problem that has long stalled the transition from fossil fuels to cleaner chemistry. The chemical industry currently relies entirely on oil and gas. While two clean alternatives have been developing in parallel—solar-powered chemistry that converts CO₂ into useful molecules, and engineered bacteria that can be programmed to make specific chemicals—they've never worked together in the same space. Existing biohybrid reactors have tried combining light absorbers with microbes, but the chemistry typically released toxic metal ions that poisoned the bacteria. Su's team solved this by engineering each component to be compatible with living cells from the start.
Here's how the reactor works: sunlight powers two simultaneous reactions in the liquid. On one electrode, water is split, releasing oxygen that the bacteria breathe. On a second electrode, an enzyme captures CO₂ from the solution and converts it into formate, a small molecule that acts like a solar-powered fuel packet. The bacteria then absorb this formate, use the oxygen to metabolize it for energy, and convert that energy into growth—building their own biomass out of more CO₂ dissolved in the same liquid. Sunlight goes in. Living bacteria come out.
The elegance of the system lies in its modularity. Each component—the organic solar cell, the enzyme, the energy carrier, the bacterial strain—can be independently redesigned and swapped without rebuilding the entire reactor. This matters enormously for scaling up. A synthetic biologist could plug in a different engineered E. coli strain to produce a target chemical beyond mere biomass: plastics, pharmaceutical precursors, food proteins, or other high-value molecules. The reactor becomes a platform rather than a fixed solution.
Dr. Celine Wing See Yeung from the University of Cambridge, part of the collaboration, described the project as a jigsaw puzzle shaped by years of research—enabling organic photovoltaics to function at high temperatures, advancing enzyme purification, and integrating it all with synthetic biology. Su himself acknowledged the work is still early. The yields remain small, and the reactor has run for hours rather than weeks. Yet the fundamental proof of concept is now established: chemistry and biology can safely coexist in a single beaker powered by sunlight.
For a truly clean chemical industry to replace the fossil-fuel system, the processes that capture carbon and the biology that converts it into products will eventually need to share the same device. Manual transfers between reactors are too slow and expensive to scale. This work represents the foundation for what researchers envision as future integrated solar refineries for chemicals, materials, and microbial protein—transforming how humanity produces the molecules that sustain modern life.