Optimization of CO2 bio-mitigation by Chlorella vulgaris

Abstract

Abstract Biofixation of \CO2\ by microalgae has been recognized as an attractive approach to \CO2\ mitigation. The main objective of this work was to maximize the rate of \CO2\ fixation ( R \CO\ 2 ) by the green microalga Chlorella vulgaris \P12\ cultivated photoautotrophically in bubble column photobioreactors under different \CO2\ concentrations (ranging from 2% to 10%) and aeration rates (ranging from 0.1 to 0.7 vvm). Results showed that the maximum R \CO\ 2 (2.22 g L−1 d−1) was obtained by using 6.5% \CO2\ and 0.5 vvm after 7 days of cultivation at 30 °C. Although final biomass concentration and maximum biomass productivity of microalgae were affected by the different cultivation conditions, no significant differences were obtained in the biochemical composition of microalgal cells for the evaluated levels of aeration and CO2. The present study demonstrated that optimization of microalgal cultivation conditions can be considered a useful strategy for maximizing \CO2\ bio-mitigation by C. vulgaris.