Comparison of different photobioreactor configurations and empirical computational fluid dynamics simulation for fucoxanthin production

Abstract Microalgae production in culture systems has been a topic of intense study for a long time. Optimization of cultivation conditions and design parameters of photobioreactors are essential for the development of economically and technically feasible algae technologies. The present study aimed to evaluate the effect of different photobioreactor (PBR) configurations on biomass and fucoxanthin production from Phaeodactylum tricornutum and to examine culture conditions by using Computational Fluid Dynamics (CFD) simulation for the photobioreactor having the maximum yield. The cells were first cultivated in three different PBRs (flat plate, airlift and stirred tank) and the maximum cell concentration of 5.94 ± 0.12 × 10 7  cells/ml was obtained in flat plate PBR. Also, highest fucoxanthin amount was found in the same PBR with the value of 2.43 ± 0.23 mg g −1 . Flat plate PBR was simulated using CFD and the obtained results were used to evaluate mixing efficiency, flow dynamics and velocity fields. The extent of mixing was found sufficient to achieve homogenous culture medium and mean turbulent kinetic energy field suggested a homogeneous dissipation, also higher intensities of turbulence were observed around the nozzles and at the liquid-gas interphase. However, dead zones and vortex formations were observed in a small proportion of PBR. For further researches, assembling mixers or baffles into the PBR may be a feasible and effective method to improve the mixing efficiency and to prevent hydrodynamic problems. It was shown that the result of cultivation experiment had good agreement with that of CFD prediction.