Biomass producing and CO2 capturing simultaneously by Chlorella vulgaris: Effect of CO2 concentration and aeration rate.

Optimizing the operational parameters of the photosynthetic process is essential for effective microalgae-based CO 2 capture and fixation. This study develops and validates models that can relate the effects of CO 2 concentration and aeration rate on relevant microalgal properties, including biomass productivity and CO 2 biofixation rate. The maximum biomass concentration was predicted as 2.80 g⋅L−1 at the optimal CO 2 concentration of 10.2 % and aeration rate of 0.55 vvm. Based on the proposed models, the CO 2 biofixation rate characterized by carbon content in dry microalgal cells, and the timings of microalgae entering the exponential growth and stationary growth phases were effectively predicted. Furthermore, the lower heating value of harvested microalgal biomass was up to 21.98 kJ⋅g−1 and the dominant fatty acid methyl esters (FAME) species were C16 – C18, highlighting the potential of Chlorella vulgaris as the feedstock for microalgae-based energy production. Consequently, microalgae present a remarkable dual function for CO 2 mitigation and renewable bioenergy production. [Display omitted] • Models simulating microalgal growth and CO 2 fixation rate were developed. • Optimal CO 2 concentration and aeration rate for cell growth were determined. • High biomass of 2.80 g L−1 was achieved at the optimal operational condition. • Chlorella shows high potential on production of combustion fuel and biodiesel. [ABSTRACT FROM AUTHOR]