This research appraised the simultaneous biofixation of carbon dioxide (CO 2 ) and nitric oxides (NO x ) by microalgae species Chlorella vulgaris , Haematococcus pluvialis , and Scenedesmus subspicatus . The experimental design was established by five treatments with gas concentrations between control – 0.04% of CO 2 , 5 to 15% of CO 2 , and 30 to 100 ppm of NOx. Parameters such as pH, growth, productivity, lipids, protein, carbon/ nitrogen ratio, and astaxanthin were evaluated. For all species, the maximal growth was achieved with 5% of CO 2 and 30 ppm of NO x . Regarding protein content, for all the three species, better results were obtained at higher concentrations of CO 2 and NOx. These results prove the microalgae capacity for CO 2 and NO x biofixation and reuse of biomass as a source of high value-added products, such as lipids, proteins, and astaxanthin. These findings support the indication of these species for flue gas treatment process and use in biorefineries systems.