Researchers teach bacterium to turn sunlight into useful chemicals

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Researchers at the University of California, Berkeley, have taught bacteria to cover themselves in tiny, highly efficient solar panels to produce useful chemical compounds.

Chemistry Professor Yang Peidong and Kelsey Sakimoto, a former graduate student now at Harvard University, fed a naturally occurring, nonphotosynthetic bacterium, Moorella thermoacetica, chemicals that made it construct their own solar collectors.

While capturing about 80 percent of sunlight's energy, the bacterium, as part of its normal respiration, uses carbon dioxide to produce acetic acid, a versatile chemical that can be upgraded to a number of fuels, polymers, pharmaceuticals and commodity chemicals through complementary, genetically engineered bacteria.

Bioreactor (left) loaded with bacteria decorated with cadmium sulfide, light-absorbing nanocrystals (middle) to convert light, water and carbon dioxide into useful chemicals (right). /Photo via acs.org

The self-replicating and self-regenerating process is about four times more efficient than natural photosynthesis using chlorophyll, which captures sunlight to convert carbon dioxide and water into starch. Their findings will be presented by the two researchers this week in Washington, DC, at the national meeting of the American Chemical Society.

The technology, as claimed by the researchers, produces zero waste.

"The thrust of research in my lab is to essentially 'supercharge' nonphotosynthetic bacteria by providing them energy in the form of electrons from inorganic semiconductors, like cadmium sulfide, that are efficient light absorbers," Yang said.

"We are now looking for more benign light absorbers than cadmium sulfide to provide bacteria with energy from light."

Chlorophyll is what gives leafy greens their color. /VCG Photo

The research is funded by the US Department of Energy and the National Science Foundation.

"Rather than rely on inefficient chlorophyll to harvest sunlight, I've taught bacteria how to grow and cover their bodies with tiny semiconductor nanocrystals," Sakimoto was quoted by a news release from UC Berkeley as explaining.

"These nanocrystals are much more efficient than chlorophyll and can be grown at a fraction of the cost of manufactured solar panels," he said.

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Source(s): Xinhua News Agency