2.2. Effect of CO2 supplementation and seasonality on microalgal productivity simulated-climate of different regions
Considering that flue gas availability could limit the achievement of maximum algal biomass potential in some regions of South America, we determined the effect of not supplementing CO2 onS. obliquus on productivity in simulated-climate of Buenos Aires, Posadas and Fortaleza. Lack of CO2 supplementation lessened annual mean biomass productivity from 10,56 ± 1,85 g · m- 2 · d-1 to 4,71 ± 0,89 g · m- 2 · d-1 (55% lower) in Buenos Aires; from 10,61 ± 1,21 g · m- 2 · d-1 to 5,18 ± 0,78 g · m- 2 · d-1 (51% lower) in Posadas; and from 16,76 ± 0,94 g · m- 2 · d-1 to 7,14 ± 0,70 g · m- 2 · d-1 (57% lower) in Fortaleza. The same level of reduction of biomass productivity was observed in summer and winter if CO2 is was not supplied (Figure 2).
Cultures not-supplemented with CO2 consistently presented slightly higher levels of carbohydrates and lipids in their biomass. However, both carbohydrates and lipids productivity was largely offset by the slower growth rate of these cultures (Figure 3).