Enhanced biomass productivity of Arthrospira platensis using zeolitic imidazolate framework-8 as carbon dioxide adsorbents

Abstract

In order to improve CO2 diffusion in algae solution and conversion into dissolved HCO3–, zeolitic imidazolate framework-8 (ZIF-8) with zinc cores as unsaturated metal sites was first used as CO2 adsorbents. Flue gas CO2 from coal-chemical industry can be adsorbed and can be made available throughout cultivation to promote biomass productivity of Arthrospira platensis. The ZIF-8 adsorbent with particle size of 719 nm performed the largest pore area of 351.8 m2/g, which promoted CO2 conversion into HCO3– by 72.9% compared to control condition without ZIF-8. The increased HCO3– concentration enhanced thylakoid membrane proportion in cell cross-sectional area by 1.3 times to 78.3%, which resulted in enhancement of photosynthesis in A. platensis cells. Relative electron transport rate increased by 9.4% accordingly, which was attributed to the improvement of chlorophyll a concentration by 110%. The biomass productivity using ZIF-8 adsorbent with particle size of 719 nm markedly increased by 64.0%.