Minghua Zhou and Tingyue Gu
Microbial Fuel Cells (MFCs) have demonstrated their capabilities under laboratory conditions to treat various types of wastewater with concomitant bioelectricity production. They can also be operated as Microbial Electrolysis Cells (MECs) with an external voltage to produce some bioproducts such as methane and hydrogen. Tremendous advances have been made in recent years in reactor configuration, electrode design, membrane design and multiunit stacking. However, the MFC and MEC technologies are still far from ready for real-world applications beyond powering small sensor devices. This work discusses bioelectrochemistry principles and various bottlenecks in MFC operations. It points out that the next breakthrough may come from the use of engineered biofilms with superior performance characteristics that greatly improve electron transfer and appetite for various organic matters in wastewater streams.