Nile Red Staining for Oil Determination in Microalgal Cells: A New Insight through Statistical Modelling

Figure 3

Emission spectra of three different experiments from the factorial experimental design (Table 2). Excitation wavelength = 530 nm. For convenience, real values (instead of coded values) of the independent variables are shown below. For all three experiments, ultrasonication power = 0 W, incubation temperature = 20°C, and poststaining time = 15 min. —: experiment  29 (stained microalgal culture); cell concentration = 0.11 g dried microalgae/L culture and Nile red dye concentration = 2.5 μg dye/mL culture. - · - · - ·: experiment  2 (stained growth medium); cell concentration = 0 g dried microalgae/L culture and Nile red dye concentration = 2.5 μg dye/mL culture. - - - - -: experiment  28 (unstained microalgal culture); cell concentration = 0.11 g dried microalgae/L culture and Nile red dye concentration = 0 μg dye/mL culture.