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Bioelectrochemistry. 2018 Apr 5;122:164-173. doi: 10.1016/j.bioelechem.2018.03.015.


Microbial electrosynthesis (MES) is a promising bioelectrochemical approach to produce biochemicals. A previous study showed that Rhodopseudomonas palustris TIE-1 can directly use poised electrodes as electron donors for photoautotrophic growth at cathodic potentials that avoid electrolytic H2 production (photoelectroautotrophy). To make TIE-1 an effective biocatalyst for MES, we need to improve its electron uptake ability and growth under photoelectroautotrophic conditions. Because TIE-1 interacts with various forms of iron while using it as a source of electrons for photoautotrophy (photoferroautotrophy), we tested the ability of iron-based redox mediators to enhance direct electron uptake. Our data show that soluble iron cannot act as a redox mediator for electron uptake by TIE-1 from a cathode poised at +100mV vs. Standard Hydrogen electrode. We then tested whether an immobilized iron-based redox mediator Prussian blue (PB) can enhance electron uptake by TIE-1. Chronoamperometry indicates that cathodic current uptake by TIE-1 increased from 1.47±0.04 to 5.6±0.09μA/cm2 (3.8 times). Overall, our data show that immobilized PB can enhance direct electron uptake by TIE-1.


© 2018. This manuscript version is made available under the CC-BY-NC-ND 4.0 license

Published version available at Bioelectrochemistry. 2018 Apr 5;122:164-173. doi: 10.1016/j.bioelechem.2018.03.015.

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