Microbial Fuel Cells (MFCs) are considered to be one of the most promising alternative renewable power sources.But MFC cannot drive almost all the present commercial electron devices because of its low output voltage and current.Power Management System (PMS) is designed to accumulate power from MFCs and then discharge it to drive the load intermittently.Super-capacitor is usually selected as the power storage device in PMS.As MFC provides limited power output

maximizing the power transferred to the super-capacitor is of great importance.A theoretical method of determining the optimal capacitance that can maximize the average power generation in a single charging cycle was presented based on the generally accepted equivalent circuit model of MFC.A single chamber air-cathode MFC experiment system was built and experiments were implemented.Simulation and experimental results show the validity of the proposed method.