Evaluation of the composition and identification of periphytic microalgae biomass in the algal turf scrubber system under different concentrations of nutrients

The main objective of this research was to evaluate the behavior of an ATS system, analyzing the microalgae taxa and biomass produced under different concentrations of nutrients. A fertilizer solution containing NPK (nitrogen, phosphorus, and potassium) in the concentrations of 1, 2, 3, 4, and 5 g L-1 was used. The highest biomass productivity, 13.3 +/- 2.5 g m(-2) days(-1), was found using 5 g L-1 of NPK. The maximum lipid content found was 9.6 +/- 1.4% (w/w) and, among the fatty acids identified, palmitic acid is found in greater abundance (35.1 +/- 9.4%). The productivity potential of the oil was estimated at 2,865 L ha(-1) year(-1). The carbohydrate concentration was 23.0 +/- 2.5% (w/w) and no statistical differences (p > 0.05) were observed between the fatty acids composition and the carbohydrate content between the samples. The productivity of the periphyton showed a positive correlation with the concentration of nutrients that enter the system. In contrast, the concentration of carbohydrates found in the biomass remained stable at all of the nutrient rates studied. The microalgae evaluation identified that most of the taxa found belong to the class Bacillariophyceae (diatoms).