Biological treatment of eutrophicated lagoon water with Tetradesmus dimorphus under ambient conditions: a sustainable alternative for lipid production

Among current environmental problems, preserving freshwater quality is vital for living beings, making it necessary to treat eutrophicated water bodies. Biological treatment of water from the lagoon El Conejo, Altamira, and Tamaulipas with Tetradesmus dimorphus resulted in 0.028 ± 0.009 g/Ld biomass, 74.24 ± 27.99% N-NO₃⁻¹ removal and 43.37 ± 20.75% of Chemical Oxygen Demand under natural conditions of radiation and temperature during 40 days of cultivation. Under gravity, sedimentation reached a yield of 74.60 ± 5.99%. The biomass observed by Scanning Electron Microscopy was spherical and 10 µm in diameter, and it also presented a lipid productivity of 3.71 ± 1.79 mg/L/day. Fourier Transform Infrared Spectroscopy analysis of lipids revealed the presence of esters, fatty acids, and phospholipids. In contrast, gas chromatography revealed the presence of linoleic, oleic, and palmitic fatty acids in relatively high proportions.