Wastewater Treatment Using Phototrophic–Heterotrophic Biofilms and Microbial Mats

Phototrophic and photoheterotrophic microbial biofilms and mats are characterized by its abundant microbial diversity and unique properties in consortia functional populations. Recently, the roles of phototrophic microbial biofilms and mats involving microalgae (diatoms, green algae and cyanobacteria, and other members of bacteria, fungi, and protozoa’s) are receiving special attention because of their promissory first results obtained in the sustainable bioremediation of environment-sensitive habitats and effluents. The bioremediation of urban wastewater in coastal-marine environments, petroleum hydrocarbons and heavy metals and metalloid toxicity is a reality. Microbial biofilms and mats also play important bioremediation roles of aquaculture effluents, in the case of Penaeidae shrimp aquaculture effluents, figures of 80–97% removal efficiencies of nitrogen and phosphorous have been reported. Reported figures on the treatment of petroleum compounds achieved removal efficiencies of 25–85%. The uniqueness of many of these properties and processes for phototrophic and heterotrophies microbial biofilms and mats have led to innovative strategies benefiting biofilm-based bioremediation and environmentally safe bioprocesses, such as microbial consortia interactions, quorum sensing, gene exchange and uses of omics technologies. The application in the deep-sea tracking associated to petroleum extraction from shale rock, and in desalination of high salt seawater effluents are technologies based on biofilms and mats already in progress.