Phototrophic microbial fuel cells

Microbial fuel cells (MFCs) are an attractive treatment concept for resource recovery from wastewater as well as being an attractive alternative energy provider, producing electricity from any location on the planet where biomass “waste” is available. Like heterotrophic organisms in general (which include the world’s fastest growing and thus fastest biotransforming species), the MFC can play an important role in recycling dead materials. Biobased transformation of wastes into new resources such as energy generation in MFC represents circular and sustainable approach which is invaluable for the environment. However, MFC cannot fully recycle all the elements (e.g., oxygen) and under normal circumstances produces carbon dioxide. Algae, being the fastest growing plants on the planet, have the ability to fix carbon dioxide and produce oxygen, so it seems natural to integrate with MFCs to produce phototrophic microbial fuel cells (PMFCs), which can fully recycle all the important elements required for life. PMFC represents an integrated system allowing for both renewable energy while helping to solve many environmentally related matters (e.g., carbon scrubbing through biosequestration, nutrient recovery, and clean water). PMFC may therefore provide a significant resolution of both environmental and energy crises at the same time. MFCs have now been developed to the point where they are being used in many practical applications, including demonstrations and field trials prior to commercial development. PMFCs are still at the experimental stage trying to find the most suitable species of microbes to use and the best methods to integrate phototrophs and heterotrophs to maximize growth and efficiency of processes. This chapter deals with a critical review of MFCs, photobioreactors, what type of waste materials can be employed by a PMFC, and what type of useful commodities can be produced, in the hope that this will become a useful resource for researchers in the field.