Research progress in microbial extracellular long-distance electron transport networks

Abstract:

Microbial electron transfer processes play a key role in both life evolution and biogeochemical cycles of various elements. In recent years, toward a deeper understanding of the microbial electron transfer, many novel microbial extracellular electron transfer strategies have been discovered, such as microbial nanowires, electrically conductive biofilms, interspecies electron transfer. Meanwhile, the electron transport distance increases from nanometer scale to centimeter scale. Generally, these long-distance microbial electron transport processes interacted and connected to each other, and form microbial electron transfer networks which play key roles in substance and energy transformations. The mechanisms and functions of microbial long-distance electron transport have been paid increasing attentions from different disciplines. Along the scale of electron transfer distance, this review introduces recent progresses in microbial long distance electron transport pathways and networks, including nanometer electron transport networks (cell periplasm space and outer surface), micro-to-millimeter electron transport networks (nanowire, inter-cellular electron transfer and conductive biofilms), and centimeter electron transport networks (cable bacteria). The challenges, problems and future research directions in this field are also discussed for providing more information to the researchers related.