Power generation of Shewanella oneidensis MR-1 microbial fuel cells in bamboo fermentation effluent

Abstract

This study successfully demonstrates the recovery of energy from the effluent of hydrogen fermentation (EHF) by generating electrical power in batch dual-chamber microbial fuel cells (MFCs) inoculated with Shewanella oneidensis MR-1. The effluent obtained from the hydrogen fermentation process of pretreated liquid on Bambusa stenostachya Hack. bamboo which contained organic compounds such as acetate, lactate, and butyrate as carbon sources for Shewanella oneidensis MR-1 and other electro-active microorganisms. Two scenarios of the anolyte of MFC were considered. The first case comprises a supply of 10 mM of lactate in hydrogen fermentation wastewater while the second one is without lactate-supply. The power density and current density of these MFCs were determined to be 0.3–0.6 W/m2 and 1.7–2.7 A/m2, respectively. The highest voltage generating from MFC without lactate addition was 0.76 V while others were around 0.65 V. The percentage of COD removal on the effluent of hydrogen fermentation ranged from 75% to 83% after 8 operational days followed by the acclimation process. The differences in the impedance characteristics of these MFCs were analyzed by using EIS technique. The average thickness of biofilm formation on the anode electrode was from 7 μm to 23 μm which showed the enhanced electricity production of the MFC system. Moreover, the experimental results demonstrated that the performance of MFC without the lactate supply was better than the other one. Also, its lower substrate consumption efficiency was mentioned.