Carbon dioxide mitigation by microalga in a vertical tubular reactor with recycling of the culture medium

Abstract

Microalgae use photosynthesis as their principal metabolic mechanism to obtain organic carbon from the inorganic carbon contained in CO 2 using solar energy. This process releases oxygen into the atmosphere. The aim of this study was to determine the most appropriate biomass concentration for growing Spirulina sp. LEB 18 (Cyanobacteria) in a vertical tubular photobioreactor with biomass removal and recycling of the medium to maximize CO 2 biofixation. The maximum CO 2 biofixation was obtained when the culture was maintained at 600 mg L-1 biomass concentration. Under this condition, the highest CO 2 biofixation value was 186.8 ± 73.1 mg L-1 d-1 , and the maximum productivity was 85.9 ± 6.0 mg L-1 d-1 .

Microalgae potential in the capture of CO2 emission

“…The main advantages of horizontal PBRs are the large surface exposed to light and the relatively low CO2 losses [31]; on the other hand, an important disadvantage is the accumulation of oxygen in the culture medium, that can lead to a decrease in biomass production and CO2 uptake [29]. Vertical PBRs, on the other hand, are advantageous for their high mass transfer and good mixing, which has made them suitable systems for biomass production and CO2 sequestration; however, they have a small illumination area, which can induce a decrease in the growth rate [32]. Another configuration commonly used for CO2 capture with microalgae are flat plate PBRs.…”

“…An important advantage is the short light path and high illumination area. An important drawback is the low mixing and high shear stress [32].…”