Fig. 6

Increasing triacylglycerol (TAG) content in N. oceanica using limited ammonium as N source. a N. oceanica (Noc) cells produce large lipid droplets during prolonged incubation in the environmental photobioreactor (ePBR) containing f/2-NH₄Cl medium. Noc cells grow fast in f/2-NH₄Cl medium and suffer from nutrient limitation after 8 days in the stationary phase, when the confocal micrographs were taken. Green fluorescence indicates lipid droplets stained with BODIPY, while red fluorescence represents autofluorescence of Noc chloroplasts. b Lipid droplet staining of M. elongata AG77 and Noc cells after 6 days co-cultivation in shaker flasks following the incubation of the algae in ePBRs. c Fatty acid (FA) analyses of triacylglycerol and total lipid in the alga-fungus aggregate as shown in (b). Biomass ratio of TAG or total FA relative to the total cell dry weight (DW). n = 5