The Kinetics of Growth and the CO₂ Concentrating Mechanism of the Filamentous Cyanobacterium Anabaena cylindrica in a Bubble Column

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The growth and CO₂ concentrating mechanism of a filamentous cyanobacterium Anabaena cylindrica IAM-M1 in a bubble column have been studied by following the time courses of biomass concentration, pH, CO₂ accumulation rate, and transmittance of light. The biomass production increased with the increasing superficial gas velocity from 9.0 m·h^–1 to 12 m·h^–1 or with increasing mole fraction of CO₂ at the inlet from 0.03 to 0.06, while it decreased with the increasing superficial gas velocity from 12 m·h^–1 to 18.0 m·h^–1 or with the increasing fraction of CO₂ from 0.06 to 0.12. As biomass concentration increased the photosynthetic photon flux density of the transmitted light decreased. The CO₂ accumulation rate, which almost equaled in magnitude the CO₂ mass transfer rate (CTR), went up steeply in the early phase of cell growth. The photosynthetic CO₂ uptake rate (CUR) reached the maximum at the late logarithmic growth phase. The maximum value of the ratio CTR/CUR was 804.