FIG. 5.

NO₃⁻ uptake and biomass yield as affected by culture aeration and initial cell density. NO₃⁻ uptake rates (A) and biomass yields (B) were the average values calculated from a cultivation period of 45 h. To prepare inocula with various initial cell concentrations, cells were precultured in BG-11 medium for 24 h, concentrated by centrifugation, and washed twice with deionized water. The x axis indicates the cell density right after inoculation. The aeration rate was set up at two levels, 0.3 (□) and 0.8 (▵) vvm. The light intensity was 160 μmol m⁻² s⁻¹, and the culture temperature was 32°C (error bars indicate standard deviations; n = 4).