Challenges and applications of nitrate-reducing microbial biocathodes

•Description of nitrate removal methods.•Review of the conditions for the growth of nitrate-reducing biocathodes.•Description of the properties of nitrate-reducing biocathodes.•Illustration of the applications of nitrate-reducing biocathodes.•Water remediation and energy production. Bioelectrochemical systems which employ microbes as electrode catalysts to convert chemical energy into electrical energy (or conversely), have emerged in recent years for water sanitation and energy recovery. Microbial biocathodes, and especially those reducing nitrate are gaining more and more attention. The nitrate-reducing biocathodes can efficiently treat nitrate-polluted wastewater. However, they require specific conditions and they have not yet been applied on a large scale. In this review, the current knowledge on nitrate-reducing biocathodes will be summarized. The fundamentals of microbial biocathodes will be discussed, as well as the progress towards applications for nitrate reduction in the context of water treatment. Nitrate-reducing biocathodes will be compared with other nitrate-removal techniques and the challenges and opportunities of this approach will be identified.