Fig. 5

Chlorophyll as proxy of triacylglycerol accumulation. a Analysis of triacylglycerol (TAG) by thin layer chromatography (TLC). Algal cells were incubated in environmental photobioreactor (ePBR) containing f/2-NH4Cl medium after inoculation to stationary phase and then prolonged incubation. Red arrowheads indicate the TAG bands. S1 to S8, day 1 to 8 after the cells reached stationary phase; control, TAG standard. b Inverse correlation of chlorophyll content and TAG-to-total-lipid ratio following prolonged incubation in the ePBR containing f/2-NH₄Cl medium. TAG and total lipid were subjected to transesterification and the resulting fatty acid methyl esters were quantified by GC–FID. r², correlation coefficient; n = 4