Microbial fuel cells exhibit low output voltages, which must be enhanced for application in practical electronic devices. However, connecting microbial fuel cells in series for voltage boosting may cause voltage reversal, resulting in energy loss and biofilm damage. In this paper, different configurations for connecting microbial fuel cells and power-management systems are investigated to boost the voltage without reversal. The best configuration of the investigated method is as follows: A single power-management system is connected to a single microbial fuel cell or parallel-connected microbial fuel cells (boosted voltage from < 0.2 V to 3.3 V); several such individual power-management systems are then connected in series (increased to 6.6 V using two power-management systems). Interestingly, when the single microbial fuel cell supplies insufficient power (e.g., activity loss such as fuel starvation) to the power-management system in series, the voltage reversal of a capacitor occurs in the series-connected power-management system, and not in the microbial fuel cell. However, the effects of this voltage reversal are outweighed by the benefits of protecting the microbial fuel cell from failure. This approach can be informative for applications of power-management systems and microbial fuel cells as a power source in practical electronic devices.