Figure 4.

Astaxanthin and ketocarotenoid productivity in different growth conditions. Productivities of astaxanthin (red) and ketocarotenoids (purple) are presented as volumetric (mg/L) (a,b) and daily volumetric (mg/L/day) (c,d) productivities obtained from bkt5 and n2bkt12 mutants in autotrophic (a,c) or mixotrophic (b,d) growth. Cells were grown in HS or TAP media for autotrophic or mixotrophic growth, respectively, at 500 or 1000 µmol photons/m²/s with air bubbling or air plus 3% CO₂ bubbling (CO₂). Data were obtained by HPLC analysis. (e,f) Cell density of bkt5 (e) or n2bkt12 (f) strains cultivated in semi‐continuous mode in 500‐mL flasks at 500 µmol photons/m²/s in TAP with 3% CO₂ bubbling and stirring. Cells were manually counted and diluted 10‐fold where they reached stationary phase. (g,h) Astaxanthin (red) and ketocarotenoid (purple) productivities obtained in semi‐continuous cultivation of bkt5 (g) or n2bkt12 (h) strains, as determined by HPLC analysis. Data are expressed as means ± standard deviation (n = 4).