These cyborg bacteria take photosynthesis to the next level

If it wasn’t for photosynthesis, we’d all be dead. Most plants would cease to exist, carbon dioxide would flood the air, and oxygen wouldn’t replenish. Suffice it to say we’d be screwed. And although the vast majority of life on Earth gets its energy from photosynthesis — the process of turning light, water, and CO2 into fuel — chlorophyll, the green pigment that enables the process, is relatively inefficient.

To improve on nature, scientists have now induced bacteria to coat themselves in microscopic, ultra-efficient “solar panels” that turn them into photosynthetic organisms, enabling them to develop important compounds. The research has turned these organisms into “cyborg” bacteria that function far more efficiently than plants.

“My initial motivation was to use these bacteria as biological whole-cell catalysts to reduce CO2 into useful chemicals,” Peidong Yang, a professor in the department of chemistry at the University of California, Berkeley, told Digital Trends. “Of course, these bacteria are not photosynthetic to start with. The cyborg bacteria become photosynthetic by directly interfacing with semiconductor nanostructures.”

Workings in Yang’s lab, researcher Kelsey Sakimoto, now at Harvard University, flipped through the scientific literature and found that certain bacteria have an innate defense to compounds like cadmium, mercury, and lead, which allows them to convert heavy metals into small crystal semiconductors. By propagating the bacteria in the lab and adding trace amounts of cadmium, the bacteria naturally produce the photosynthetic crystals on their surface.

“These bacteria do not have light-absorbing capability to start with,” Yang said. “However, once they interface with semiconductor nanostructures, these cyborg bacteria become photosynthetic as the semiconductor will absorb the sunlight and generate the electrons, and pass them onto the CO2 reduction pathway inside these bacteria, and as a result value-added chemical can be produced directly from CO2 using sunlight.”

The researchers think their bacteria can offer a better source of alternative energy as they don’t require some of the same electrical hook-ups that more “conventional” green energy methods require. The lab results suggest these bacteria just need tubs of liquid and sunlight, although more research needs to be conducted to refine the process.

“Once covered with these tiny solar panels, the bacteria can synthesize food, fuels, and plastics, all using solar energy,” Sakimoto said in a statement. “These bacteria outperform natural photosynthesis.”

The researchers presented their breakthrough findings this week at the American Chemical Society conference in Washington.