Developing a Zigzag-baffled Column Photobioreactor to Increase Mass-Transfer, CO2 Fixation and Biomass Yield During A. Platensis Cultivation

The present work aims to evaluate performance of a novel zigzag-flow column photobioreactor (ZZ-flow PBR) designed to achieve a high biomass during A. platensis cultivation. The ZZ-flow PBR was installed with four optimized zigzag baffle structures mounted over its outer (riser) section. The optimum parameters (w = 18 and h= 5 cm) for each zigzag baffle structure generated zigzag flow patterns throughout microalgae solution, which decreased mixing time (MT) by 51.1% but increased mass transfer coefficient (MTC) by 58.2% as compared with traditional PBR. The solution followed zigzag path along the baffles to facilitate frequent movement of microalgae cells across the PBR, where overall photochemical efficiency phi PSII and Fv/Fm increased by 21.4% and 12.4%, respectively. The intracellular photosynthesis promoted electron transfer rate (ETR) by16.6% and chlorophyll a content by 8.3%, resulting in an increased biomass yield and CO2 fixation by 28.8% and 36.3%, respectively, relative to conventional column PBR.