EET-mediated systems have the potential to be much safer, and cheaper to manufacture than \(H_2\)-mediated systems. It is not clear if the efforts needed to make this approach work are worth it, considering the difficulties of cultivation and genetic manipulation of these organisms. A significant concern raised about using EET-mediated organisms is that the mode of life this draws inspiration from, metal oxidation, relies upon low reduction potential electron sources. In the absence of any external energy source (some metal oxidizers such as Rhodopseudomonas palustris (REF JIao 2001) can use light as an additional source of energy, although we do not consider this here), it requires microbes to somehow up-convert the energy of the electrons using a system called "the uphill pathway” (REF BIRD 2011). Despite a power conversion to a lower potential, this results in a loss of electrons due to the inability in this system are a cause for serious concern.
To understand the energetics of the abiotic carbon fixation approach in EET- mediated system, we have built a 2- cell circuit (Figure 2D). The current from an idealized solar photovoltaic is split between 2 cells, one that is assigned to abiotic carbon fixation, while the other is assigned to microbial reduction of the initial product of carbon fixation from the first cell to a biofuel. The current from the panel is divided so that an adequate number of electrons are sent to the second cell to fully reduce the fixed carbon from the first cell to a biofuel. The carbon fixation rate to the primary carbon fixation production in the initial fixation cell,