Optimization of CO2 Biofixation by Chlorella vulgaris Using a Tubular Photobioreactor

Abstract The effects of various CO 2 concentrations in CO 2 bioconversion by cultivation of microalga Chlorella vulgaris were investigated using a vertical tubular photobioreactor. The response surface technique with central composite design was applied to model the CO 2 biofixation rate, the specific growth rate (SGR), and the biomass productivity of C. vulgaris as function of CO 2 concentration and cultivation time. The developed nonlinear model was employed to determine the optimum CO 2 concentration in an air‐CO 2 mixture and the cultivation time for maximum CO 2 biofixation, SGR, and microalgae biomass productivity. In addition, a multiple responses optimization method was also applied to determine the maximum CO 2 uptake rate, the SGR, and the biomass productivity, simultaneously. The predicted optimum values agreed well with the experimental data.