**1. Introduction**

Microalgae have aroused the scientific community's interest by their biotechnological potential and increased commercial demand because these microorganisms are an excellent source of a wide range of chemicals with biomedical interest (e.g., carotenoids, essential fatty acids, polyphenols, polysaccharides, etc.) [1–3]. In addition, they are helpful for bioremediation applications in wastewater treatment and other decontamination applications [4, 5]. Some advantages of this biological system are that bioremediation reinforces biogeochemical processes, toxic chemicals are degraded and not simply physically separated from the environment, and the process requires less energy than other technologies and uses less manual supervision. Furthermore, the bioaccumulation of heavy metals by microalgae cells may represent a feasible method for the treatment of leachates and wastewater containing bioavailable heavy metals [6–10].

Additionally, microalgae could be cultivated in wastewater lagoons with small nutrient requirements for their maintenance and development. This component usually constitutes the final step to completing the decontamination process in many wastewater treatment systems [11–13]. Therefore, massive cultivation of microalgae using wastewater as a source of nutrients is a cost-effective approach due to the simplicity of the technology allowing both pollutants (i.e., biological and chemical) remotion and the obtention of a valuable microalgae biomass rich in proteins, lipids, pigments, bioactive chemicals, etc. [14–17].

In this context, this chapter aims to provide updated information based on the results of investigations conducted by our research team using some strains from the freshwater microalgae collection culture native from the Peruvian Amazon.
