In this paper, we investigated the use of polyamidoamine (PAMAM) dendrimer-encapsulated platinum nanoparticles (Pt-DENs) as a promising type of cathode catalyst for air-cathode single chamber microbial fuel cells (SCMFCs). The Pt-DENs, prepared via template synthesis method, have uniform diameter distribution with size range of 3-5 nm. The Pt-DENs then loaded on to a carbon substrate. For comparison, we also electrodeposited Pt on carbon substrate. The calculation shows that the loading amount of Pt-DENs on carbon substrate is about 0.1 mg cm(-2), which is three times lower than that of the electrodeposited Pt (0.3 mg cm(-2)). By measuring batch experiments, the results show that Pt-DENs in air-cathode SCMFCs have a power density of 630 5 mW m(-2) and a current density of 5200 +/- 10 mA m(-2) (based on the projected anodic surface area), which is significantly better than electrodeposited Pt cathodes (power density: 275 +/- 5 mW m(-2) and current density: 2050 +/- 10 mA m(-2)). Additionally, Pt-DENs-based cathodes resulted in a higher power production with 129.1% as compared to cathode with electrodeposited Pt. This finding suggests that Pt-DENs in MFC cathodes is a better catalyst and has a lower loading amount than electrodeposited Pt, and may serve as a novel and alternative catalyst to previously used noble metals in MFC applications. (C) 2011 Elsevier B.V. All rights reserved.