Researchers at Binghamton University, State University of New York have developed the next step in microbial fuel cells (MFCs) with the first micro-scale self-sustaining cell, which generated power for 13 straight days through symbiotic interactions of two types of Bacteria.
In a cell chamber about one-fifth the size of a teaspoon -- 90 microliters -- researchers placed a mixed culture of phototrophic and Heterotrophic Bacteria. Phototrophic Bacteria uses sunlight, carbon dioxide, and water to make its own energy, while heterotrophic bacteria must "feed" on provided organic matter or phototrophic bacteria to survive -- think of cows grazing in a grassy field.
While the cell was exposed to sunlight, an initial dose of "food" was added to the chamber to stimulate growth of the heterotrophic bacteria. Through cellular respiration, the heterotrophic bacteria produced carbon dioxide waste, which was used by the phototrophic bacteria to kickstart the symbiotic cycle.
After that cycle was established, researchers stopped adding additional "food" sources for the heterophic bacteria, and there was enough phototrophic bacteria to sustain the metabolic processes of the heterophic bacteria. Those metabolic processes generated an electrical current -- 8 microamps per square centimeter of cell -- for 13 straight days. The power was about 70 times greater than current produced by phototrophic bacteria alone.
For details see:
Lin Liu, Seokheun Choi. Self-sustaining, solar-driven bioelectricity generation in micro-sized microbial fuel cell using co-culture of heterotrophic and photosynthetic bacteria. Journal of Power Sources, 2017; 348: 138 DOI: 10.1016/j.jpowsour.2017.03.014
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Posted by Dr. Tim Sandle