Editorial: Current Challenges and Future Perspectives on Emerging Bioelectrochemical Technologies

In its simplest form, bioelectrochemical systems (BESs) consist of an anode, a cathode, and a microbial catalyst (Rabaey and Rozendal, 2010). One of the attractive features of bioelectrochemical technology is that, BESs can be developed to implement anodic-based or cathodic-based bioprocesses or both at the same time. For example, pollutants can be degraded by a specialized microbial catalyst at the anode while the electrons and protons generated can be used by a biocathode to synthesize useful chemicals. Among the notable applications of BESs, the most extensively studied is microbial fuel cell, a technology developed over the last century for the production of electrical energy from chemical substrates oxidized by a microbial catalyst at the anode (Potter, 1911; Logan and Rabaey, 2012). BESs can also be used to reduce CO 2 into methane or multicarbon chemicals including biofuels at the cathode with external electrical energy coming from renewable energy sources (Lovley and Nevin, 2013; Tremblay and Zhang). Besides greenhouse gas emissions control, one of the purposes of this application termed microbial electrosynthesis is to store electricity surplus in ready-to-use chemicals. A derived technology consists in powering a BESs reactor with solar cell for the production of chemicals thus mimicking natural photosynthesis. This approach is intensively pursued because it has the potential to have a solar-to-chemicals conversion efficiency significantly higher than traditional photosynthetic biomass-based bioprocesses (Nevin et al., 2010; Zhang, 2015). In the domain of chemicals production, BESs are also developed to electrify white biotechnologies where the substrates of the microbial catalyst are organic carbon molecules (Choi et al., 2014; Harnisch et al., 2015). In this case, BESs are employed to optimize the redox balance of production bioprocesses resulting in improved yield and profitability. Additionally, BESs are used for environment-cleaning applications aiming for example at polishing wastewaters or at removing petroleum derivatives, heavy metals, azo dyes, and chlorinated organic compounds from contaminated sites (Logan and Rabaey, 2012; Wang et al., 2015). Employing BESs for bioremediation provides an unceasing source of electron acceptor or donor eliminating the need for costly chemical amendments. Water desalination, biosensors, H 2 production, and investigative tools to monitor biological activity are other bioelectrochemical technologies of note (Cao et al., 2009; Tremblay and Zhang). Although BESs are versatile systems with promising features, most bioelectrochemical technologies developed until now have been restricted to lab scale. Low production rate and limited efficiency have stymied scaling up. To overcome this challenge, electroactive …