Review Article | Published:

Electroactive microorganisms in bioelectrochemical systems

Nature Reviews Microbiologyvolume 17pages307319 (2019) | Download Citation


A vast array of microorganisms from all three domains of life can produce electrical current and transfer electrons to the anodes of different types of bioelectrochemical systems. These exoelectrogens are typically iron-reducing bacteria, such as Geobacter sulfurreducens, that produce high power densities at moderate temperatures. With the right media and growth conditions, many other microorganisms ranging from common yeasts to extremophiles such as hyperthermophilic archaea can also generate high current densities. Electrotrophic microorganisms that grow by using electrons derived from the cathode are less diverse and have no common or prototypical traits, and current densities are usually well below those reported for model exoelectrogens. However, electrotrophic microorganisms can use diverse terminal electron acceptors for cell respiration, including carbon dioxide, enabling a variety of novel cathode-driven reactions. The impressive diversity of electroactive microorganisms and the conditions in which they function provide new opportunities for electrochemical devices, such as microbial fuel cells that generate electricity or microbial electrolysis cells that produce hydrogen or methane.

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The authors acknowledge funding by the US Department of Energy (DOE) Energy Efficiency and Renewable Energy (EERE) Fuel Cell Technologies Office through a contract from the National Renewable Energy Laboratory (NREL), Project #21263, and by the Environmental Security Technology Certification Program via cooperative research agreement W9132T-16-2-0014 through the US Army Engineer Research and Development Center.

Author information


  1. Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, PA, USA

    • Bruce E. Logan
    •  & Ruggero Rossi
  2. Biological and Environmental Sciences and Engineering Division, Water Desalination and Reuse Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia

    • Ala’a Ragab
    •  & Pascal E. Saikaly


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All authors researched data, wrote the article and reviewed and edited the manuscript before submission. B.E.L. and R.R. prepared drafts for figures 1 and 3–5, and P.E.S. and A.R. prepared figure 2.

Competing interests

The authors declare no competing interests.

Corresponding authors

Correspondence to Bruce E. Logan or Pascal E. Saikaly.

Supplementary information


Bioelectrochemical systems

Devices that contain microorganisms that donate to or accept electrons from an electrode.

Microbial electrochemical technologies

(METs). Bioelectrochemical systems that are used for a specific purpose, for example, microbial fuel cells used to produce electricity.


An electrolyte that surrounds the cathode when a bioelectrochemical system is divided into two chambers; if there is only one chamber, the cathode is exposed to the anolyte.


The ability of microorganisms to transfer electrons outside the cell.


The ability of microorganisms to accept electrons into the cell from external sources.


A single-chamber microbial fuel cell (MFC) is an MFC with an air cathode that is exposed to air on one side and water on the other side. By contrast, two-chamber systems are reactors with a membrane that separates the anode and cathode chambers.


The electrolyte that surrounds the anode in a bioelectrochemical system. In one-chamber systems, the cathode is exposed to the same electrolyte.


Cathodes that transfer electrons to microorganisms on the electrode surface.

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