Fig. 2

Effect of the harvesting period on the volume and morphological changes in the lipid droplets. Algal cell stained with BODIPY 505/515 and viewed under fluorescence microscopy with a 450–490 nm band excitation filter and a 515-nm-long emission filter (a–d). Fluorescence of the dye in the presence of cellular lipids can be seen as green fluorescence. In microalgae, autofluorescence of chlorophyll is also observed with red fluorescence. Micrograph of microalgal cells under bright field (e–h). Microalgal cells were cultured for 2 days (a, e), 4 days (b, f), 10 days (c, g), and 14 days (d, h). The cells were incubated at 30 °C in the BPS and underwent 48 h of lipid induction