In less than a decade the levels of performance of microbial fuel cells (MFCs) in terms of current output, voltage, and power density have grown tremendously according to steady exponential trends. Achievements occurred over the past 2-3 years have been particularly impressive. This is due partly to a better understanding of the biological aspects of this multidisciplinary technology, but also to systematic work undertaken by several research groups worldwide aimed at improving and optimizing aspects related to materials and system configuration. Aim of this review is to outline the current perspective about MFCs by focusing on the recent major advances in the areas of materials and engineering. MFCs are promising devices to address sustainability concerns both in terrestrial and space applications.

h i g h l i g h t sOlive mill wastewater (OMW) represents a problem for its disposal and treatment. Single-chamber MFC was used to produce electricity from OMW and wastewater (DW). MFCs fed with DW plus OMW gave 0.38 V (1 kO) and a power density of 124.6 mW m À2 . TCOD and BOD 5 of DW plus OMW mix was reduced of 65% and 50% respectively. Microbial characterization of electrodes bacterial communities indicate anode differences. Improving electricity generation from wastewater (DW) by using olive mill wastewater (OMW) was evaluated using single-chamber microbial fuel cells (MFC). Doing so single-chambers air cathode MFCs with platinum anode were fed with domestic wastewater (DW) alone and mixed with OMW at the ratio of 14:1 (w/w). MFCs fed with DW + OMW gave 0.38 V at 1 kO, while power density from polarization curve was of 124.6 mW m À2 . The process allowed a total reduction of TCOD and BOD 5 of 60% and 69%, respectively, recovering the 29% of the coulombic efficiency. The maximum voltage obtained from MFC fed with DW + OMW was 2.9 times higher than that of cell fed with DW. DNA-fingerprinting showed high bacterial diversity for both experiments and the presence on anodes of exoelectrogenic bacteria, such as Geobacter spp. Electrodes selected peculiar consortia and, in particular, anodes of both experiments showed a similar specialization of microbial communities independently by feeding used.