Electric currents are produced when the transfer of these electrons to anodes is coupled to the oxidation of intracellular organic wastes. Previous research has proposed that the high conductivity of Geobacter biofilms can be used to power microbial fuel cells and to generate electricity from organic waste products. In particular, G. sulfureducens holds one of the highest records for microbial fuel cell current density that researchers have ever been able to measure in vitro. This ability can be attributed to biofilm conductivity, as highly conductive biofilms have been found to be positively correlated with high current densities in microbial fuel cells.
At the moment, the development of microbial fuel cells for power generation purposes is partly restricted by its inefficiency compared to other sources of power and an insufficient understanding of extracellular electron transfer. As such, many researchers are currently studying how we can utilize biofilm conductivity to our advantage to produce even higher current densities. Low pH environments have been found to change redox potentials, thus inhibiting electron transfer from microorganisms to cytochromes. In addition, biofilms have been found to become less conductive with decreasing temperature, although raising the temperature back up again can restore biofilm conductivity without any adverse effects. The presence of pili or flagella on Geobacter species has been found to increase electric current generation by enabling more efficient electron transfer. These different factors can be tweaked to produce maximum electricity and to optimize bioremediation in the future.
In a University of Massachusetts Amherst study, a neuromorphic memory (memristor) utilized Geobacter biofilm cut into thin nanowire strands. The nanowire strands conduct a low voltage similar to that of a neurons in a human brain. In a paper co-authored by Derek Lovely, Jun Yao observed that his team can "modulate the conductivity, or the plasticity of the nanowire-memristor synapse so it can emulate biological components for brain-inspired computing....". The breakthrough observation came as they monitored voltage activity at a sub 1 volt level.
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