Sequestration of CO2 using microalgae is one of the imperative, cost effective and environment‐friendly processes for carbon sequestration and for production of biomass. In the present study, a cyanobacterial consortium was used for the sequestration of CO2 at diverse initial CO2 concentrations (5–30%), pH of the medium (7–11) and inoculum sizes (5–12.5%). The cyanobacterial consortium showed sustainability in growth upto 30% CO2. The overall CO2 fixation capacity was found as 0.0692 and 0.071 mol CO2/g algae at 15% CO2, pH 9 and at 10% and 12.5% inoculum, respectively, after 14 days. Characterization of dry biomass before and after CO2 sequestration was done using Fourier Transform Infrared spectroscopy. Various algorithm of artificial neural network (ANN) model and a number of activation functions were tried to arrive at best ANN model for such process. Finally, Particle swarm optimization was used for optimization of input variables for maximum sequestration of CO2.