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

Table 4

Summary of previous studies on microalgal Nile red staining.

Study	Microalgal species	Excitation and emission wavelength (nm)	Optimum poststaining time (min)	Optimum Nile red dye concentration (µg/mL)	Optimum staining temperature (°C)	Main solvent	Cosolvent (use of auxiliary step)
This study	Tetraselmis suecica	530 and 607	15	4.69	40	Acetone	—
Bertozzini et al. [6]	Skeletonema marinoi,; Alexandrium minutum, and; Chaetoceros socialis	547 and 580	6	0.25	Room (20)	Acetone	IPA
Chen et al. [7]	Chlorella vulgaris, other minor species	530 and 575	10	0.50	40	DMSO	—
Chen et al. [11]	Pseudochlorococcum sp.,; Scenedesmus dimorphus, and; Chlorella zofingiensis	490 and 580	1	1.00	Not mentioned (assumed to be 40–50)	Acetone	DMSO (microwave-assisted)
Cirulis et al. [16]	Chlorella vulgaris,; Scenedesmus dimorphus	488 and 564–606	30	5–10	Room (20)	Acetone or DMSO	—
Doan and Obbard [13]	Nannochloropsis sp.	480 and 575	5–10	0.70	Room (20)	Acetone	DMSO or glycerol
Huang et al. [9]	Various Chlorella species	480 and 570–590	4	2.00	Not mentioned	DMSO	—
Lee et al. [8]	Botryococcus braunii	490 and 585	10	1.00	Not mentioned	Acetone	—
Pick and Rachutin-Zalogin [15]	Various Dunaliella species	488 and 580–625	5	1.27	25	DMF	Glycerol

Chen et al. [7] also briefly investigated Nile red staining of other microalgal species: Ankistrodesmus pseudobraunii, Nannochloris sp., C. zofingiensis, Desmodesmus quadricauda, and Palmellococcus miniatus.