Carbon dioxide utilisation of Dunaliella tertiolecta for carbon bio-mitigation in a semicontinuous photobioreactor

• Published in: Applied microbiology and biotechnology Vol. 98; no. 7; pp. 3157 - 3164
• Main Authors: Farrelly, Damien J, Brennan, Liam, Everard, Colm D, McDonnell, Kevin P
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.04.2014; Springer Berlin Heidelberg; Springer; Springer Nature B.V
• Subjects: Algae; Analysis; Anthropogenic factors; autotrophs; Batch production; Biomass; biomass production; Biomedical and Life Sciences; Bioremediation; Biotechnology; bottles; Carbon; Carbon Cycle; Carbon dioxide; Carbon Dioxide - metabolism; Carbon dioxide fixation; Carbon fixation; Cultivation; Culture; Dunaliella tertiolecta; emissions; Environmental aspects; Environmental Biotechnology; Experiments; Food science; Gases; Life Sciences; Membrane reactors; Microalgae; Microbial Genetics and Genomics; Microbiology; Organic carbon; oxygen; Photobiology; Photobioreactors - microbiology; Photosynthesis; Productivity; Studies; Volvocida - growth & development; Volvocida - metabolism; Ireland; Mitigation; Microalgae; CO; Carbon; Semicontinuous
• ISSN: 0175-7598; 1432-0614
• DOI: 10.1007/s00253-013-5322-y

Bio-fixation of carbon dioxide (CO₂) by microalgae has been recognised as an attractive approach to offset anthropogenic emissions. Biological carbon mitigation is the process whereby autotrophic organisms, such as microalgae, convert CO₂ into organic carbon and O₂ through photosynthesis; this process through respiration produces biomass. In this study Dunaliella tertiolecta was cultivated in a semicontinuous culture to investigate the carbon mitigation rate of the system. The algae were produced in 1.2-L Roux bottles with a working volume of 1 L while semicontinuous production commenced on day 4 of cultivation when the carbon mitigation rate was found to be at a maximum for D. tertiolecta. The reduction in CO₂ between input and output gases was monitored to predict carbon fixation rates while biomass production and microalgal carbon content are used to calculate the actual carbon mitigation potential of D. tertiolecta. A renewal rate of 45 % of flask volume was utilised to maintain the culture in exponential growth with an average daily productivity of 0.07 g L⁻¹ day⁻¹. The results showed that 0.74 g L⁻¹ of biomass could be achieved after 7 days of semicontinuous production while a total carbon mitigation of 0.37 g L⁻¹ was achieved. This represented an increase of 0.18 g L⁻¹ in carbon mitigation rate compared to batch production of D. tertiolecta over the same cultivation period.