Microbial fuel cells (MFCs) use bacteria to convert the chemical energy of a particular substrate contained in wastewater into electrical energy. This is achieved when bacteria transfer electrons to an electrode rather than directly to an electron acceptor. Their technical feasibility has recently been proven and there is great enthusiasm in the scientific community that MFCs could provide a source of "green electricity" by exploiting domestic and industrial waste to generate power. By using organic matter in wastewater as a fuel, contaminants are removed from water while generating electricity. The design of new materials has led to increased levels of power being generated, particularly when compared with the levels possible using common materials. Moreover, the use of inexpensive materials, such as ceramic membranes or non-platinum catalysts, makes it possible to obtain a feasible device to produce electricity. However, it is necessary to improve the performance of MFCs before they can be scaled up since, to date, their practical implementation is not feasible. Therefore, the global objective pursued by researchers is the development and evaluation of low cost catalysts (non-precious metals) for improving electron acceptor reduction (new cathodes), new biocompatible anodes and membranes, and novel configurations which improve the power and the wastewater treatment efficiency of MFCs, while reducing their cost. This review is intended to provide a critical and global vision of recent advances in microbial fuel cells and the potential applications of this technology. In this article, an overview over all aspects concerning MFC technology is provided, including issues such as new anode and cathode materials, types of membranes, MFC configurations, their application in the treatment of different types of wastewaters, bioenergy production, modeling and future perspectives. (C) 2015 Elsevier B.V. All rights reserved.