Physiology of Shewanella; Geomicrobiology.
Jeffrey Gralnick has extensively studied the physiology of Shewanella, a species of gram-negative bacteria found throughout the world in aquatic environments. By understanding the molecular mechanism that enables this species to respire a diversity of compounds - including insoluble minerals - he hopes to engineer strains that can generate power in microbial fuel cells or react against certain toxic metals in the environment.
Working in collaboration with Prof. Daniel Bond, Gralnick made a key discovery about how bacteria can convert organic compounds into electricity. It was observed that riboflavin (commonly known as vitamin B-2) was responsible for much of the energy produced by Shewanella bacteria growing on electrodes. Riboflavin produced by the bacteria was able to carry electrons from the living cells to the electrodes, and rates of electricity production increased by 370 percent as riboflavin accumulated. This finding has major implications for the development of scaled-up microbial fuel cells using similar bacteria.
Gralnick is developing strains, tools and techniques for increasing the robustness of using Shewanella for metabolic engineering and downstream applications in both Bioenergy (microbial fuel cells), Bioremediation and Biocatalysis.
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