Contaminants of emerging concern (CECs) are micropollutants (MPs) released into the environment from a wide variety of sources, industrial, agricultural, and domestic activities, which pose a prominent threat to the environment. Most of the emerging contaminants (ECs) endanger the public health, but the antibiotics urged the research towards developing effective degradation technologies due to fact that they induce antibiotic resistance. It is know that the conventional physicochemical treatment technologies are inefficient in treating MPs containing wastewater or involve high cost, require high input, or generate a large amount of toxic sludge. Thus, the recent focus in this area is towards the biological treatment system. Numerous species of bacteria and fungi capable of degrading micropollutants are reported in the literature (Ahmed et al, 2017).

Microbial degradation of MPs is associated with catabolic activity of microbes, and during the process they get assimilated as growth substrates. Microbial growth on micropollutants depends on various operating conditions such as optimum temperature, pH, doubling time, light requirement, and agitation, which indirectly affects the pollutant degradation. Pollutant properties such as surface properties, aqueous solubility, and charge are some important factors that determine the treatment efficiency.Nowadays, the microalgae are considered good candidates for the bioremediation of wastewaters (Tolboom et al., 2019) and, more than that, the biodegradation of ECs (Díaz‐Quiroz et al. 2020; Sutherland and Ralph, 2019; Gentili and Fick, 2017; Hom Díaz, 2016). Numerous recent studies were made to explore the potential of microalgae to treat the contaminating ECs in wastewater by adsorption, accumulation, photodegradation and hydrolysis (Ge and Deng, 2015; Leng et al., 2020; Sun et al., 2020, Yu et al., 2017).
A major advantage of microalgae as biocatalysts is that they can use a variety of carbon sources nutrients, capacity to develop in natural media without sterile conditions, but the more attractive is their potential to sustain photoautotrophic metabolism that is the use of light, as energy source, to fix the CO2. Supplementary the microalgae biomass is a valuable resource for added value compounds such as long chain polyunsaturated fatty acids, neutral lipids, proteins, carbohydrates, pigments, vitamins etc. (Cuellar-Bermudez et al., 2015) which can be an approachable alternative for the bioremediation process. The valuable bioremediation solutions for the contaminated water, using algae cultures in controlled cultivation conditions will take in account the follow steps: (1) selection of microalgae strains based of their resistance of the toxicity of the targeted ECs; (2) ECs content reduction in aquatic simulated media using selected strains; (3) bioprocess parameters optimization using design of experiments; (4) bioprocess control and mathematical modelling; (5) bioremediation process validation and propose the solutions to be applied in the wastewater pilot plants.
References
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