Metabolic survey of Botryococcus braunii: Impact of the physiological state on product formation
a. BODIPY505/515 staining of cell colonies after 12 days of cultivation. (i) DIC image of single BODIPY505/515-stained colony, (ii) chlorophyll autofluorescence channel, (iii) BODIPY channel, false colored green, (iv) Merge of DIC, BODIPY, chlorophyll autofluorescence images. Bar 25 μm. Yellow and white arrows indicate cytoplasmic oil bodies and extracellular hydrocarbons, respectively. b. Determination of total chlorophyll and organic dry weight (oDW) of the cell biomass during cultivation period of 30 days. c.Illustration of the color change of the cultures during the course of the cultivation. Images show the cultures after 6, 12 and 21 days of culturing as well as the corresponding biomass dry weight. d. Measurement of the C/N ratio and nitrogen (NO3-N) content in the media supernatant during cultivation period of 30 days. Numbers at the top of the graph (I to IV) represent the proposed distinct growth stages of B. braunii cells, referred as Phases I–IV. Error bars represent standard error of mean value of three biological and three technical replicates (SE; n = 9).