The performance of a cyanobacterial biomass-based microbial fuel cell (MFC) inoculated with Shewanella oneidensis MR-1

Abstract

Cyanobacterial biomass is a rich renewable resource for direct bioelectricity generation in biomass-based microbial fuel cells (MFCs). In this study, the performance of a double chamber MFC with Anabaena vaginicola cyanobacterial biomass as the anodic substrate was investigated. The anode chamber was inoculated with a pure culture of Shewanella oneidensis MR-1, and different MFC experiments using pretreated and untreated cyanobacterial biomass substrate with 5 or 20 mg/L riboflavin were conducted. Pretreatment of the biomass and addition of 20 mg/L riboflavin led to the highest current density (366 mA/m3), maximum power density (144 mW/m3), chemical oxygen demand removal efficiency (65%), and coulombic efficiency (5.7%). Increasing the concentration of riboflavin improved bioelectricity generation (1.4–1.7-fold increase in maximum power density), confirming its effectiveness as a redox mediator, and its role in the extracellular electron transfer process of the S. oneidensis MR-1 biofilm. Moreover, pretreating the biomass also enhanced the conversion efficiency of biomass to bioelectricity. This indicated that pretreatment of the biomass influenced the utilization of biomass by S. oneidensis MR-1 cells. These findings can help increasing the potential of using renewable substrates for more efficient bioenergy generation in pure culture MFCs.