## 1 Introduction  
Microalgae biomass production has received great interest in recent decades, partially due to its great capacity to capture CO\({}_{2}\) compared to terrestrial crops [1]. In addition, microalgae biomass can provide a wide variety of organic compounds of commercial interest (i.e., polysaccharides, biopeptides, biopolymers, antioxidants and pigments), and also, being rich in carbohydrates and oils, it provides the ability to produce bioenergetics (biomethane, biohydrogen, biodiesel, and bioethanol) [2, 3]. Furthermore, the microalgal biomass can be used as food and animal feed because of its high protein content [4]. The microalgae can be grown using various water resources, including freshwater, seawater, and even industrial or domestic wastewater [5]. Biomass derived from microalgae has significant advantages over biomass derived from other sources [6, 7]. One of the advantages of microalgae cultivation is that it does not require arable or forested land for its production [8; 9]. They also have high growth rates, can double their biomass in periods as short as 3.5 h, and can be produced in continuous processes in contrast to other sources of biomass production [6; 10]. Despite the wide application of microalgae, there are many challenges in the development of technology for the use of biomass, among them the following stand out: (1) the selection of the microalgae species must have as essential requirements the maximum production of lipids, the type of lipids with potential for the production of bioenergetics and the co-products of interest that could be extracted; (2) achieve higher photosynthetic efficiencies through continuous development of production systems; (3) minimize evaporation and CO\({}_{2}\) losses due to limited diffusion in open crops; (4) negative energy balance after taking into account the requirements of water pumping, CO\({}_{2}\) transfer, harvest, and oil extraction; (5) a lack of data for large-scale plant because few commercial plants are in operation; (6) incorporation of unsuitable combustion gases due to the presence of toxic compounds in high concentrations such as NOx and SOx [11]. Even with the challenges posed by the production of microalgal biomass, the expected increase in the world population will cause a growing demand for natural resources, which favors the production of bioenergetics from sources that do not generate an overpressure of these resources [7; 11]. Some research groups have focused on the investigation of microalgae species genetically modified to improve biomass production and lipid content. In addition to this, these investigations seek the generation of co-products of high economic value that improves the economic profitability of the process [12; 13]. Microalgae have a great capacity to capture CO\({}_{2}\), which can come from the atmosphere or directly from combustion gas emissions. They can capture CO\({}_{2}\) up to 1.7-1.8 times their weight (dry basis) due to their high photosynthetic capacity [14; 15; 16]. There is a growing interest in analyzing the biomass production of microalgae using CO\({}_{2}\) from the flue gases of thermoelectric plants as a carbon source [14; 17; 18; 19; 20]. It has been reported that even integrating CO\({}_{2}\) emissions, biomass production is still not economically viable, therefore it is believed that including wastewater bioremediation (as a source of nutrients) and co-production of biofuels and microalgae bioproducts (a biorefinery concept) will achieve a promising approach improving the economics of the overall process [12; 21; 22]. Intracellular compounds and metabolites of microalgae have gained immense importance due to their high monetary value. For example, microalgae pigments like chlorophyll \(a\), chlorophyll \(b\), lutein, astaxanthin, \(\beta\)-carotene, phycobilins, C-phycocyanin have found wide application in food, feed additives, cosmetics, nutraceuticalals, and pharmaceuticals agents.