The air‐lift photobioreactors with flow patterning for high‐density cultures of microalgae and carbon dioxide removal

Abstract

A photobioreactor containing microalgae is a highly efficient system for converting carbon dioxide (CO2) into biomass. Using a microalgal photobioreactor as a CO2 mitigation system is a practical approach to the problem of CO2 emission from waste gas. In this study, a marine microalga, Chlorella sp. NCTU‐2, was applied to assess biomass production and CO2 removal. Three types of photobioreactors were designed and used: (i) without inner column (i.e. a bubble column), (ii) with a centric‐tube column and (iii) with a porous centric‐tube column. The specific growth rates (μ) of the batch cultures in the bubble column, the centric‐tube and the porous centric‐tube photobioreactor were 0.180, 0.226 and 0.252 day−1, respectively. The porous centric‐tube photobioreactor, operated in semicontinuous culture mode with 10% CO2 aeration, was evaluated. The results show that the maximum biomass productivity was 0.61 g/L when one fourth of the culture broth was recovered every 2 days. The CO2 removal efficiency was also determined by measuring the influent and effluent loads at different aeration rates and cell densities of Chlorella sp. NCTU‐2. The results show that the CO2 removal efficiency was related to biomass concentration and aeration rate. The maximum CO2 removal efficiency of the Chlorella sp. NCTU‐2 culture was 63% when the biomass was maintained at 5.15 g/L concentration and 0.125 vvm aeration (volume gas per volume broth per min; 10% CO2 in the aeration gas) in the porous centric‐tube photobioreactor.

Bench-Scale Cultivation of Microalgae Scenedesmus almeriensis for CO2 Capture and Lutein Production

“…In terms of CO 2 capture efficiency, S. almeriensis performance are comparable with performances of several microalgal species [55,56].…”

Lipid Induction in Dunaliella salina Culture Aerated with Various Levels CO2 and Its Biodiesel Production

“…[14]. Moreover, these species can be grown well under the natural light-dark cycle and are suitable for large scale outdoor cultivation systems [15]. Since, industrial exhaust gases containing 10.0-20.0% CO 2 , these algae species are not inhibited by CO 2 with 50 ppm, but it can be inhibited by CO 2 when nitrogen oxides (NOx) is present [16].…”

CO2 bioremediation by microalgae in photobioreactors: Impacts of biomass and CO2 concentrations, light, and temperature

“…1 illustrates three types of basic photobioreactors ; (i) without inner column (i.e. a bubble column), (ii) with a centric-tube column, and (iii) with a porous centric-tube column [76]. As shown in Table 1 (Table 1).…”