Bioelectrogenesis from Raw Algal Biomass Through Microbial Fuel Cells: Effect of Acetate as Co-substrate

Algae are autotrophic organisms that are widespread in water bodies. Increased pollution in water bodies leads to eutrophication. However, algae growing in lakes undergoing eutrophication could be utilized towards the generation of added-value bio-electricity using microbial fuel cells (MFCs). In the present study, two methods of electricity generation using raw algae (RA) and RA + acetate (AC) as co-substrate were analyzed in single chamber air cathode MFCs. MFCs supplemented with RA and RA + AC clearly showed higher power density, greater current generation, and improved COD (chemical oxygen demand) removal, which demonstrated the feasibility of using AC as substrate for MFC. The MFC-RA + AC (0.48 mA) generated 28% higher current relative to that generated by MFC with RA alone. Notably, the maximum power densities generated by MFC-RA and MFC-RA + AC were 230 and 410 mW/m², respectively. MFC-RA and MFC-RA + AC exhibited TCOD (total chemical oxygen reduction) removal values of 77% and 86.6%, respectively. Despite the high influent TCOD (758 mg/l) concentration, the MFC-RA + AC exhibited an 8.5% higher COD removal relative to that of MFC-RA (525 mg/l). Our current findings demonstrated effective energy generation using algae biomass with a co-substrate.