Analyzing the Impact of Physicochemical Factors on Chlorella vulgaris Growth Through Design of Experiment (DoE) for Carbon Capture System

The CO 2 emission is increasing every year and threatening both humans and the ecosystem. Carbon capture technological innovations have emerged as a potential solution to mitigate this emissions. Due to its high capacity of photosynthetic activity, CO 2 sequestration by microalgae, such as Chlorella vulgaris has attracted much attention as a carbon capture system. The growth of this microalgae is influenced by various physicochemical factors. By designing the Design of Experiment (DoE) with Response Surface Methodology (RSM), the effect of several independent factor can be evaluated to optimize Chlorella vulgaris growth condition and CO 2 conversion. This study aims to identify the most impact factors affecting C. vulgaris growth through investigating the variations in physicochemical factors of aeration, initial pH, dark light regime, saline, and substrates concentration using DoE. In this study, C. vulgaris was cultivated in batch culture for 10 days with 8 experiments that were designed under various conditions as per experimental run. Biomass growth was observed using optical density and analyzed by first order regression. The result shows that aeration parameters was statistically significant affect microalgae growth, evidence by p -value below 0.05 at all observation points. Runs with aeration treatment showed a prolonged exponential growth phase and delayed onset of the deceleration phase. Additionally, this study also found that the initial pH level also significantly affects growth at the last day of cultivation. Cultures with a higher initial pH reached the stationary phase earlier than those with a lower pH. Thus, the growth of C. vulgaris can be optimized by adding aeration treatment into culture media and regulating initial pH around 8 to enhancing carbon fixation and biomass yield.