Modeling Growth of Chlorella sorokiniana by Changing CO2 Nutrient Concentration

Abstract

Algae research has gained significant attention due to its potential in carbon capture and biofuel production. Understanding the role of CO2 in algae growth is critical to optimize these processes. This study investigates the impact of CO2 on the growth of Chlorella sorokiniana under various experimental conditions. All experiments were conducted at a temperature of 35°C, a light intensity of 234 µmol m-2 s-1, and a 12-hour light window. For the main set of experiments, CO2 flow percentage was changed from 5% to only air flow to see the effect on growth rate. The results showed that excess CO2 doesn’t significantly affect growth, however when it is no longer in excess as concentration drops the growth rate decreases. A one-parameter model was applied to the data, providing values that accurately represent the data. In another experiment, the effects of CO2 flow being on always was compared with CO2 flow only being on during the light phase. The results supported the hypothesis that CO2 flow at night has a negligible impact on growth. In the final experiment, the flowrate of air was lowered while CO2 flow remained the same across both runs. This would be so that one run would have a total flow of 2 LPM and the other a total flow of 1 LMP. This is because although air flow is needed for oxygen content, excess can strip the CO2 from the reactor reducing efficiency. The results confirmed this as the 1 LPM experiment had a lower pH, meaning that there was more dissolved CO2 in solution.