The mechanism and application of bidirectional extracellular electron transport in the field of energy and environment

Abstract

Bidirectional extracellular electron transfer (EET) is mediated by back and forth electron delivery between microorganisms and extracellular substances. This enables the exchange of biochemical information and energy with the surrounding environments. As a novel bioenergy strategy, bidirectional EET provides low-cost opportunities for the production of clean energy sources and carriers (e.g., hydrogen and methane) as well as the production of value-added chemicals from carbon dioxide. Electrochemically active bacteria (EAB) can also transform pollutants to less toxic or benign substances in contaminated environments, and therefore they have been widely applied in bioremediation studies. Among all the available EAB, Geobacter and Shewanella are well-known for their versatility to accept/donate electrons from/to external environments. In this review, we focus on how these model EAB generate or harvest energy through bidirectional EET, as well as recent advances in the application of EET in bioelectrochemical technology and environmental bioremediation. Finally, the challenges, perspectives and new directions in the bidirectional EET studies are discussed.

Graphical abstract

Keywords:

• Bioremediation
• energy production
• extracellular electron transfer

Additional information

Funding

This work was supported by the National Natural Science Foundation of China (Grant Nos. 51709100, 51579096, 51521006, and 51222805), the Fundamental Research Funds for the Central Universities (531107050936), the Key Research and Development Program of Hunan Province of China (2017SK2241), the National Innovative Talent Promotion Program of China (2017RA2088), and the National Program for Support of Top-Notch Young Professionals of China (2012). The research of SA has been supported by SIAM Gravitation grant “Microbes for Health and the Environment” (Project 024.002.002) of the Netherlands Ministry of Education, Culture and Science, and the Netherlands Science Foundation (NWO).