Algae based microbial fuel cells for wastewater treatment and recovery of value-added products

Microalgae based microbial fuel cells are efficient systems to remove nitrogen, phosphorous and CO2 from wastewater, to produce bioelectricity and value-added products from microalgal biomass. Microalgae can be used in MFCs as algae assisted cathode systems, microbial carbon capture cells or sediment microbial fuel cells as well as photosynthetic microalgae microbial fuel cell. These MFCs are shown efficient for CO2 capture with a low risk of carbon emission, N and P removal via symbiotic interactions of microalgae-bacteria consortia in wastewater treatment along with power generation. The oxygen production by microalgae during the light period reduces the need for external oxygen supply for cathodic reactions, which is advantageous for reducing the aeration cost, as otherwise power needs to be supplied for mechanical aeration. Utilization of algal biomass harvested from the cathodic compartment requires a pretreatment in a biorefinery concept. This still remains a major drawback, but current advances towards the choice of a biofilm on the cathode allow for further recovery of value-added products from algal biomass. Alternatively, the algal biomass can be utilized as the sole feedstock in the anodic compartment. This paper reviews the application of algae based microbial fuel cells for bioelectricity production, mainly focusing on the use of algae in the cathodic compartment, microalgae in the anodic compartment and the main interactions between the compartments affecting the bioelectricity production.