Figure Captions
Figure 1. Schematic overview of the chemostatic experimental setup: (1) Acid bottle; (2) Base Bottle; (3) the fresh medium container; (4) Effluent flask; (5) Gas bottle; (6) Cryostat; (7) Thermostat; (8) pH probe; (9) DO probe; (10) Applikon photobioreactor; (11) Stirrer motor with four-blade impellers; (12) Condenser; (13) Acid pump; (14) Base pump; (15) Two-head Masterflex pump using for feed and effluent; (16) Stirrer speed controller; (17) Air pump; (18) Off-gas analyzer; (19) A Bio Controller ADI; (20) Mass flow controller; (21) Digital monitor Flowmeter; (22) PC; (23) Light source
Figure 2. Microscopic pictures of species present in culture after reaching steady-state under different nitrogen loading rate. Nitrogen loading rate for A, B, C, D and E series are 10, 20, 32.5, 42 and 63 mgN.l-1.d-1 corresponding to feed composition of F1, F2, F3 and F4 for nitrogen limitation and F5 for light limitation, respectively. The left and right pictures are under normal and fluorescence light, respectively. The scale bar represents 30 µm.
Figure 3. The nitrogen to dry weight and active biomass (X) ratio for different nitrogen loading rates.