Editorial: Wired for Life

Fossil fuels and fossil fuel derived chemicals are limited, non-renewable, and foreseen to run out in the near future. To find viable solutions for the production of renewable fuels and chemicals, significant efforts are being made by the scientific community. For example, some microorganisms have been shown to produce fuels or chemicals using renewable electricity charged electrodes as electron donors for their metabolism (Tremblay and Zhang). The ability to utilize insoluble substrates such as electrodes is due to the property of certain microorganisms to release or take up electrons from insoluble substrates, a process known as extracellular electron transfer (EET). During EET to a solid electron acceptor, cells dispose of excess electrons indirectly by exploiting shuttles, or directly via a network of conductive pili and cytochromes (Lovley et al., 2011). The same EET mechanisms are considered to assist microorganisms when taking up electrons from solid electron donors, however less is known about this process (Tremblay and Zhang). Microorganisms also use direct EET for syntrophic interspecies interactions between a donor species and an acceptor species (Kouzuma et al.; Shrestha and Rotaru). The papers in this research topic present insights into EET and how this process governs microbe–microbe, microbe–mineral, and microbe–electrodes interactions.