Feasibility of CO2 mitigation and carbohydrate production by microalga Scenedesmus obliquus CNW-N used for bioethanol fermentation under outdoor conditions: effects of seasonal changes

Table 1 Performance of biomass production, carbohydrate production, and CO₂ fixation of large-scale batch cultivation of S. obliquus CNW-N under indoor conditions with different durations of nitrogen depletion

Cultivation time under nitrogen depletion (d)	Biomass productivity (mg L⁻¹d⁻¹)	Carbohydrate (glucose) content (%)	Carbohydrate (glucose) productivity (mg L⁻¹d⁻¹)	CO₂ fixation rate (mgL⁻¹d⁻¹)^a
Nitrogen rich	408.4 ± 20.9	18.4 ± 2.9 (12.7 ± 1.3)	75.1 ± 4.7 (51.8 ± 3.1)	717.7 ± 33.7
0	397.5 ± 13.1	26.2 ± 1.7 (19.5 ± 0.9)	104.2 ± 5.6 (77.6 ± 2.9)	695.7 ± 22.8
1	393.4 ± 15.4	35.5 ± 2.4 (28.7 ± 1.5)	139.5 ± 8.1 (112.8 ± 6.7)	688.5 ± 26.9
2	378.1 ± 9.7	41.0 ± 3.1 (33.9 ± 2.9)	154.9 ± 8.3 (128.0 ± 7.9)	661.7 ± 16.8
3	360.5 ± 10.2	44.8 ± 2.4 (37.5 ± 1.1)	161.4 ± 6.7 (135.3 ± 5.5)	630.8 ± 17.9
4	341.1 ± 11.6	50.0 ± 2.7 (42.4 ± 1.0)	170.7 ± 6.4 (144.7 ± 5.3)	596.9 ± 20.3
5	319.2 ± 13.2	50.0 ± 3.6 (42.1 ± 2.1)	159.6 ± 7.8 (134.6 ± 6.9)	558.5 ± 23.1

Values are the mean ± standard deviation of three replicated experiments. (Light intensity = 500 μmol m⁻²s⁻¹; CO₂ feeding concentration = 2.5%; working volume = 60 L.)
^aCalculated from the following equation: CO₂ fixation rate = Biomass productivity (mg L⁻¹d⁻¹) × C(%) × 44/12

ISSN: 2731-3654