Developing a Zigzag-baffled column photobioreactor to increase mass-transfer, CO2 fixation and biomass yield during A. platensis cultivation. (September 2022) - Kubar, Ameer Ali
Abstract: 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 φPSII 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. Graphical Abstract: ga1 Highlights: A zigzag-flow PBR decreased mixing time and increased mass transfer by 51.1% and 58.2%. Four layers of zigzag baffle improved nutrient homogeneity throughout solution. Efficient mixing benefited A. platensis movement and enhanced photochemical efficiency. Zigzag baffles significantly promoted CO2 dissolution and fixation. The biomass dry weight of A. platensis has increased by 28.8% and reached to 3.15 g/L.