Kinetic modeling of microalgae growth and CO_2 bio-fixation using central composite design statistical approach

摘要

The optimum growth (μ), CO_2 bio-fixation (R_(CO_2)) rates and the energy ratio (ER) of microalgae Chlorella vulgaris (C.v) were identified using central composite design statistical approach (CCD-SA).μand R_(CO_2) parameters including temperature of photobioreactor (T_(PBR)). concentration of CO_2 (C_(CO_2)). nutrients (carbon, nitrogen and phosphorus), gas flow rate (Q_(gas)), initial inoculum concentration (IN_(den)) and the solar light intensity (f_(tot)) were considered. Results revealed mild operational conditions in the range 20-25 ℃, C_(CO_2) of 2.5-20% (v/v), Q_(gas) of 0.5-0.8 vvm and I_(tot) of 50-200 μE/m~2 • s would generate considerable μ and R_(CO_2) The highest μ and R_(CO_2) with a significant ER of 19.5 were generated under CCD-SA optimized parameters of T = 25 ℃, C_(CO_2) = 20%, Q_(gas) = 0.5 ± 0.05 (Std. Dev. = 0.04) vvm, total inorganic nitrogen (TN) = 19 ± 2 (Std. Dev. = 0.1) mg-N/L, Total phosphorous = 7 ± 1 (Std. Dev. = 0.7) mg-P/L, COD = 20 ± 2 (Std. Dev. = 0.5) mg-COD/L, IN_(den) = 0.52 ± 0.01 (Std. Dev. = 0.05) mg/Land I_(tot) = 150 ± 2(Std. Dev. = 0.6) μE/m~2s). Microalgae technology can be considered as a promising technology for CO_2 bio-fixation in a large scale with a sustainable value of the produced bio-mass for biofuel production.