Solar PV Cells Powered by Living Bacteria

Renewable energy is here to stay, but it still faces some major hurdles in the way. In the case of solar PV, performance is hindered in northern regions with low solar radiation. Also, in spite of the reduced production costs and increased efficiency over the last few years, it is still uncommon to find average power conversion efficiency above 25%. Currently, silicon is the main material employed for these solar cells but that may soon change. And not thanks to cutting edge materials such as graphene, but through one of the oldest forms of life in our planet—bacteria. Specifically, one with a pretty bad reputation, E. coli, known for wreaking havoc in the human digestive system.

The innovative technology is the outcome of the research carried out by a group of scientists in British Columbia, Canada. In order to improve the efficiency of solar cells they have opted for a biogenic approach, i.e, using living organisms to produce electricity. To that end, they have used the dye used by bacteria to carry out their photosynthesis processes. Prior research had tried to extract the natural dye and apply it on solar cells. The process, however, was costly and toxic. Therefore, the team from British Columbia tried another approach, this time based on genetic engineering. Instead of extracting the dye, they engineered the E. coli bacteria, so they produced a larger amount of lycopene, the same substance that gives tomatoes their characteristic red color. The bacterial culture was mixed with a mineral semiconductor and then spread over a glass sheet. The scientists verified that the bacteria could produce electricity even under extremely low light conditions, such as cloudy days.

The outcome is certainly encouraging, as they have doubled the electricity generated in previous experiments, increasing it from 0.362 milliampere to 0.686 per square centimeter. According to Vikramaditya Yadav, the scientist leading the team, this is the highest electrical output achieved from a biogenic PV cell.

Although it is too soon to assess the exact savings provided by the new technology, Yadav stresses that these cells would be produced very cheaply and in a sustainable way. Also, the solar PV cells applications could extend to submarine exploration.

Biosynthonics, a green chemistry

Vikramaditya Yadav is one of the pioneers of a new research field that could have a great impact on other areas beyond energy, like drugs. Yadav has named this new field as “biosynthonics”. In an article published a few years ago in the journal ACS, the Indian scientist pointed out the diminishing returns in the development of new drugs. Currently, they require investments north of one billion dollars and over ten years of development. These issues drove him to explore new approaches and implement the benefits of genetical engineering.

Basically, biosynthonics is the search and synthesis of bioactive molecules, which can broaden the scope of chemical research. This process, called “metabolic engineering”, allows to synthesize new drugs of interest for the pharmaceutical industry and medicine by modifying genes or metabolic processes found in microorganisms.

Source: ACS, Science News, Tech Xplore