ABSTRACT
In order to solve the problems of short residence time and low diffusion of CO2 gas in microalgal solution, calcinated metal-organic framework MIL-100(Fe) were first used as CO2 adsorbents to promote the growth of Arthrospira platensis cells by increasing carbon fixation. The adsorbent (MIL-100(Fe)-4â¯h) containing unsaturated metal sites, improved the conversion of CO2 to dissolved inorganic carbon by 52.3% and concentration of HCO3- by 20.0% in culture medium, as compared to the medium without CO2 adsorbent added. The increased HCO3- concentration facilitated carboxysome accumulation (increased to 21.7 times) to activate the photosynthetic Calvin cycle in Arthrospira cells. The increased cell growth rate promoted cell volume by 132% and knot length by 102%, while the fractal dimension of the cell surface decreased by 13.5%. The biomass productivity of Arthrospira cells cultivated with the CO2 adsorbent MIL-100(Fe)-4â¯h remarkably increased by 81.9%.
