Detection and quantitation of lipid in the microalga Tetraselmis subcordiformis (Wille) Butcher with BODIPY 505/515 staining

BODIPY 505/515, a lipophilic bright green fluorescent dye was tested for lipid detection in the microalga Tetraselmis subcordiformis. A concentration of 0.28 μg ml−1 and staining for 6 min was optimal. Lipid bodies stained with BODIPY505/515 had a characteristic green fluorescence. Their volumes were determined using the sphere volume formula. Lipid accumulation under different nitrogen concentrations was analyzed. With an increase in NaNO3 concentration from 0 to 240 mg L−1, the maximum algal concentration increased from 8.23 ± 0.62 (×105 cells ml−1) to 1.61 ± 0.13 (×106 cells ml−1), while the maximum volume of intracellular neutral lipid decreased from 9.78 ± 1.77 μm3 cell−1 to 6.00 ± 0.59 μm3 cell−1. A comparison of the lipid contents measured by BODIPY 505/515 staining and the gravimetric method showed a positive correlation coefficient of R2 = 0.93. BODIPY 505/515 staining is a promising method in lipid quantitation in T. subcordiformis.

► BODIPY 505/515 staining is a promising method for neutral lipid determination in T. subcordiformis.
► A concentration of 0.276 μg ml−1 and staining for 6 min was optimal.
► High concentrations of nitrogen improved cell growth but decreased lipid volume.
► The optimum NaNO3 concentration for lipid production was 120 mg L−1.
► A correlation coefficient of R2 = 0.934 for BODIPY 505/515 staining and gravimetric analysis of lipids was obtained.