One of the major limiting factors in the practical implementation of Microbial Fuel Cells is finding efficient and sustainable catalysts for the cathode half reaction, in an attempt to avoid expensive and/or toxic catalysts. The use of phototrophic organisms is one good option since they can act as efficient in-situ oxygenators thus facilitating the cathodic reaction. In the present study, the oxygen production by photosynthetic organisms was shown to be light dependant, which resulted in increasing the power generation by 42%. Furthermore, this study showed that a previously abiotic cathode that turned biotic showed a clear light response with an improved performance of 48%. Oxygen depletion in a water-based cathode can be avoided with the use of photosynthetic biocatalysts, thus providing sustainable operation for MFCs. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.