Artificial photosynthesis with bacteria

MIT Technology Review : Using bacteria and semiconducting nanoscale materials, scientists have demonstrated the first working example of artificial photosynthesis. Peidong Yang of the University of California, Berkeley, and colleagues have developed a two-step process that uses those materials to turn carbon dioxide, water, and sunlight into useful organic compounds. First, they created a semiconducting nanowire array that captures energy from sunlight and transmits it to electrotrophic organisms embedded in the wires; the organisms use that energy to reduce water and carbon dioxide to acetic acid. Then, genetically engineered Escherichia coli convert the acetate into liquid fuels, polymers, pharmaceutical precursors, and other useful chemicals. Although the system is as efficient as natural photosynthesis, it is not efficient enough for commercial purposes. Improving the semiconductor materials and replacing the bacteria with a synthetic catalyst could speed up the process and increase its stability, says Yang.