Substrate salinity: A critical factor regulating the performance of microbial fuel cells, a review

Substrate salinity is a critical factor influencing microbial fuel cells (MFCs) performance and various studies have suggested that increasing substrate salinity first improves MFC performance. However, a further increase in salinity that exceeds the salinity tolerance of exoelectrogens shows negative effects because of inhibited bacterial activity and increased activation losses. In this review, electricity generation and contaminant removal from saline substrates using MFCs are summarized, and results show different optimal salinities for obtaining maximum performance. Then, electroactive bacteria capable of tolerating saline environments and strategies for improving salinity tolerance are discussed. In addition to ohmic resistance and bacterial activity, membrane resistance and catalyst performance will also be affected by substrate salinity, all of which jointly contribute the final overall MFC performance. Therefore, the combined effect of salinity is analyzed to illustrate how the MFC performance changes with increasing salinity. Finally, the challenges and perspectives of MFCs operated in saline environments are discussed. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

Substrate salinity plays a critical role in the performance of microbial fuel cells (MFCs), with moderate increases improving performance but excessive salinity causing negative effects. Different MFCs have optimal salinity ranges, and strategies for improving salt tolerance in electroactive bacteria can enhance performance. In addition to ohmic resistance and bacterial activity, substrate salinity also affects membrane resistance and catalyst performance, all of which contribute to the overall MFC performance.