Sustainable CO2 Capture and Bio-Fixation Using Functionalized Deep Eutectic Solvents and Microalgae †
by
and
Eliza-Gabriela Brettfeld
1,2, 
Daria Gabriela Popa
1,3,
Corina Moga
4,
Tănase Dobre
2,
Diana Constantinescu-Aruxandei
1 and
Florin Oancea
1,3,*
1
Bioresources and Polymers Departments, National Institute for Research & Development in Chemistry and Petrochemistry—ICECHIM, Splaiul Independenței nr. 202,6th District, 060021 Bucharest, Romania
2
Faculty of Chemical Engineering and Biotechnology, National University of Science and Technology Politehnica Bucharest, Splaiul Independenței nr. 313, 060042 Bucharest, Romania
3
Faculty of Biotechnologies, University of Agronomic Sciences and Veterinary Medicine of Bucharest, Bd. Mărăști nr. 59, 011464 Bucharest, Romania
4
Research and Development Department, DFR Systems SRL, Drumul Taberei 46, 061392 Bucharest, Romania
*
Author to whom correspondence should be addressed.
†
Presented at the 19th International Symposium “Priorities of Chemistry for a Sustainable Development”, Bucharest, Romania, 11–13 October 2023.
Proceedings 2023, 90(1), 35; https://doi.org/10.3390/proceedings2023090035
Published: 18 December 2023
The urgent need to mitigate anthropogenic CO2 emissions has spurred innovative approaches for CO2 capture and utilization. In this study, we explore a novel method involving the capture of CO2 using a functionalized deep eutectic solvents (DESs) [1,2] and subsequent bio-fixation through microalgae cultivation [3]. The study focuses on the development of an integrated system that efficiently captures CO2 and harnesses the photosynthetic capabilities of microalgae for sustainable CO2 reduction.
Two DESs were compared: a binary DES, ChCl:MEA 1:8 (CM) and a ternary DES, ChCl:EG:MEA (CEM) 1:2:1 molar ratio. Choline chloride (ChCl) is a hydrogen bond acceptor, while ethylene glycol (EG) and monoethanolamine (MEA) are hydrogen bond donors. The CO2 capture took place in a glass bubbler with ceramic diffuser. The desorption process involved immersing the DES in a stainless-steel container, subjecting it to a controlled temperature of 80 °C, and agitating at 12 RCF (Relative Centrifugal Force) within a full vacuum, ensuring effective desorption of CO2 from the DES. The CO2-enriched gas was introduced into a microalgae bioreactor series, where it served as a carbon source for photosynthesis [4]. The microalgae culture, Chlorella sp. NIVA-CHL137, was cultivated under controlled environmental conditions, including a day/night photoperiod (13/11 h) and BG-11 cultivation medium. The optical density (OD) and biomass yield were used to evaluate the microalgae development.
The microalgae cultivation in the bioreactor showed CO2 fixation capabilities, resulting in a significant increase in the microalgal biomass and a corresponding reduction in CO2 concentration within the system. Using the binary DES (CM) resulted in a significant 26% increase in OD of Chlorella sp. compared to control and the bio-sequestration of 53 mg of carbon per liter, equivalent to an elevation of 194 mg CO2 per liter of culture. The ternary DES (CEM), on the other hand, exhibited slightly higher CO2 concentration removal than CM (+1.4%), leading to higher OD and biomass augmentation, compared to the control culture. Additionally, CO2 desorbed from CEM positively influenced the biomass growth of Chlorella sp. compared to control, with OD surging by 12% during the initial 7 days and a sustained 24.7% increase until day 14, surpassing the performance of the control group (Figure 1).
Our study presents an approach for CO2 capture and bio-fixation using functionalized DES and microalgae cultivation. The CO2 desorption process, coupled with the prolific growth of microalgae, highlights the viability of this integrated system as an environmentally friendly and sustainable strategy for mitigating CO2 emissions. This innovative method has the potential to contribute significantly to the global efforts aimed at addressing climate change and advancing the utilization of captured CO2 in various applications, including biofuels and bioproducts.
Author Contributions
Conceptualization, F.O.; methodology, E.-G.B. and D.G.P.; validation, E.-G.B., D.G.P., D.C.-A. and C.M.; formal analysis, D.C.-A. and T.D.; investigation, E.-G.B. and D.G.P.; resources, C.M.; data curation, D.C.-A.; writing—original draft preparation, E.-G.B.; writing—review and editing, F.O.; visualization, E.-G.B.; supervision, F.O. and T.D.; project administration, F.O and E.-G.B.; funding acquisition F.O. All authors have read and agreed to the published version of the manuscript.
Funding
The research leading to these results has received funding from European Regional Development Fund (ERDF), the Competitiveness Operational Programme (POC), Axis 1, project POC-A1-A1.2.3-G-2015-P_40_352, My_SMIS 105684, “Sequential processes of closing the side streams from bioeconomy and innovative (bio)products resulting from it—SECVENT”, subsidiary project 1882/2020—AquaSTIM.
Institutional Review Board Statement
Not applicable.
Informed Consent Statement
Not applicable.
Data Availability Statement
Data is contained within the article.
Conflicts of Interest
The authors declare no conflict of interest and DFR Systems SRL has no conflict of interest.
References
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Figure 1.
Comparison between Chlorella sp. microalgal cultures grown in the presence of CO2 desorbed from ChCl:MEA 1:8 (CM) and ChCl:EG:MEA 1:2:1 (CEM) in comparison to controls; (a) Optical Density (OD), (b) Biomass. The bars represent standard errors. Columns labeled with different letters are significantly different for p > 0.05.
Figure 1.
Comparison between Chlorella sp. microalgal cultures grown in the presence of CO2 desorbed from ChCl:MEA 1:8 (CM) and ChCl:EG:MEA 1:2:1 (CEM) in comparison to controls; (a) Optical Density (OD), (b) Biomass. The bars represent standard errors. Columns labeled with different letters are significantly different for p > 0.05.
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MDPI and ACS Style
Brettfeld, E.-G.; Popa, D.G.; Moga, C.; Dobre, T.; Constantinescu-Aruxandei, D.; Oancea, F. Sustainable CO2 Capture and Bio-Fixation Using Functionalized Deep Eutectic Solvents and Microalgae. Proceedings 2023, 90, 35. https://doi.org/10.3390/proceedings2023090035
AMA Style
Brettfeld E-G, Popa DG, Moga C, Dobre T, Constantinescu-Aruxandei D, Oancea F. Sustainable CO2 Capture and Bio-Fixation Using Functionalized Deep Eutectic Solvents and Microalgae. Proceedings. 2023; 90(1):35. https://doi.org/10.3390/proceedings2023090035
Chicago/Turabian StyleBrettfeld, Eliza-Gabriela, Daria Gabriela Popa, Corina Moga, Tănase Dobre, Diana Constantinescu-Aruxandei, and Florin Oancea. 2023. "Sustainable CO2 Capture and Bio-Fixation Using Functionalized Deep Eutectic Solvents and Microalgae" Proceedings 90, no. 1: 35. https://doi.org/10.3390/proceedings2023090035
