New Phototrophic Factories for Resource Recovery

Human activities are threatening the environment. Pollutants are spread across the ecosystems damaging the biological diversity and human health. New sustainable practices must be brought forward and phototrophic organisms may contribute to overcome such complex challenge. Enclosed on these living organisms are a multitude of enzymes and metabolic pathways that act as a unit providing solutions to each environmental scenario. Phototrophic systems have been explored for their capability of recovering carbon, nitrogen, and phosphorous from the most diverse wastewater streams enabling water reutilization and the production of value-added products. And all simply using sunlight as their energy source. This chapter will provide an overview of the diversity of phototrophic organisms and elucidate on current phototrophic technologies that aim the prevention and mitigation of environmental pollution, acting on wastewater treatment and resource recovery. Two case studies will be detailed, one regarding phosphorous recovery with a photo-enhanced biological phosphorus removal system, and other regarding carbon recovery in the form of polyhydroxyalkanoates, a biodegradable polymer produced in purple phototrophic bacteria ponds. These innovative photosynthetic factories address society’s request for sustainable practices where waste is no longer the end of a production line, but instead, a fundamental and integrated element of the circular economy.