The advantages of integrating bioelectrochemical systems into anaerobic wastewater treatment reactors have been established over the last decade. In addition to enhancing biogas yield, its integration also improves biogas quality, eliminating the need for additional purification before its utilization as an energy source. While the biochemical and electrochemical processes in a hybrid AD-MEC system with a constant external electric field are well studied, the effects of a pulsed electric field remain insufficiently explored. In this study, the influence of periodic polarization using a pulsed power supply on biogas yield from distillery wastewater (vinasse and ethanol stillage) in an AD-MEC system was investigated. The experiments were performed at three different pulsed power supply frequencies with 0.8 V- 1.0 Hz (1s), 0.2 Hz (5s) and 0.1 Hz (10s). The results were compared with those obtained with a constant electric field (0.8 V) and a control mode without MEC. Low-frequency pulsed power supply (0.1 and 0.2 Hz), resulted in higher biogas yield and methane content compared to both the high-frequency mode and constant electric field. For ethanol stillage, the biogas yield increased by 20-25% relative to the control, and for vinasse by 13-16% under the optimal conditions.