Algal biofilms: Potential wastewater treatment applications and biotechnological significance

Abstract

Algae are ubiquitous autotrophic unicellular to multicellular thallophytes. They grow naturally in aquatic environments, including the wastewaters, and their biomass can be harvested easily in benthic conditions. Algae, in association with other microorganisms, form a thin film that attaches itself to solid surfaces enclosed in a matrix of extracellular polymeric substances (EPS). Therefore, the algal–microbial consortium has dominated the biofilm communities that colonize the illuminated surfaces under moisture and nutrients. Like bacterial biofilms, algal biofilms can respond to environmental changes, establish colonies on a surface, and isolate one colony or clumps from a surface. Though algal biomass is a low-cost nutrient removal source for bioproduct processing, its efficient application in wastewater treatments is not accepted worldwide. The chapter discusses the processes of algal-based wastewater treatment biofilm systems on the basis of the available literature, prohibiting efficient systems from being developed and applied to municipal, agricultural, and agrarian waste stream applications. The chapter outlines the need to explore factors influencing algal formation, mass migration, species collection, algal–bacterial interactions, and laboratory testing to establish an algal biofilm-based technical framework to combine wastewater treatment and biomass processing. © 2022 Elsevier Inc. All rights reserved.