An insoluble iron complex coated cathode enhances direct electron uptake by Rhodopseudomonas palustris TIE-1

Karthikeyan Rengasamy, Tahina Ranaivoarisoa, Rajesh Singh, Arpita Bose

Research output: Contribution to journalArticlepeer-review

30 Scopus citations

Abstract

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 +100 mV 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 ± 0.09 μA/cm2 (3.8 times). Overall, our data show that immobilized PB can enhance direct electron uptake by TIE-1.

Original languageEnglish
Pages (from-to)164-173
Number of pages10
JournalBioelectrochemistry
Volume122
DOIs
StatePublished - Aug 2018

Keywords

  • Electron uptake
  • Microbial electrosynthesis
  • Photoelectroautotrophy
  • Prussian blue
  • Rhodopseudomonas palustris TIE-1

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