Journal Article

Extracellular Electron Uptake: Among Autotrophs and Mediated by Surfaces

Tremblay, Pier-Luc, Angenent, Largus T., Zhang, Tian

2017

Overview

Autotrophic microbes can acquire electrons from solid donors such as steel, other microbial cells, or electrodes. Based on this feature, bioprocesses are being developed for the microbial electrosynthesis (MES) of useful products from the greenhouse gas CO2. Extracellular electron-transfer mechanisms involved in the acquisition of electrons from metals by electrical microbially influenced corrosion (EMIC), from other living cells by interspecies electron transfer (IET), or from an electrode during MES rely on: (i) mediators such as H2; (ii) physical contact through electron-transfer proteins; or (iii) mediator-generating enzymes detached from cells. This review explores the interactions of autotrophs with solid electron donors and their importance in nature and for biosustainable technologies. Extracellular electron transfer (EET) mechanisms involved in interspecies electron transfer (IET) and biocorrosion mediated by electrical microbially influenced corrosion are similar to those responsible for the transfer of electrons from the cathode electrode to the microbial catalyst during microbial electrosynthesis (MES). MES reactors have multiple promising applications, such as converting CO2 and electricity surpluses into value-added products, artificial bioinorganic photosynthesis, and enriching the methane fraction of biogas generated by wastewater treatment plants. MES reactor architecture is constantly evolving to improve energetic efficiency, performance, and stability. Better understanding of EET routes between solid electron donors and microbes would open new horizons in the development of MES technologies and IET-based technologies and for the prevention of biocorrosion.

• Publisher: Elsevier Ltd,Elsevier Limited
• Subject: Apoptosis / Autotrophic Processes / Autotrophs / Bacteria / Bacteria - chemistry / Bacteria - metabolism / biocorrosion / Biogas / Bioreactors - microbiology / Carbon dioxide / Carbon Dioxide - chemistry / Carbon Dioxide - metabolism / Corrosion / Cytochrome / Electric contacts / Electrochemical Techniques / Electrodes / Electron transfer / Electrons / Enzymes / extracellular electron transfer / Extracellular Space - chemistry / Extracellular Space - metabolism / Greenhouse gases / Hydrogen / Hydrogen - chemistry / Hydrogen - metabolism / Internal Medicine / interspecies electron transfer / Metabolism / Metals / microbial electrosynthesis / microorganisms / Oxidation / proteins / steel / Surface Properties