Abstract
The atmospheric concentration of CO2, the main greenhouse gas (GHG), has increased rapidly since the beginning of the industrial age. Anthropogenic emissions from coal-fired power plants are responsible for approximately 7% (w/w) of global CO2 emissions. Microalgae CO2biofixation is a technology that reduces GHGs based on the use of solar energy through photosynthesis to capture and use the CO2 that is produced by thermal and other sources. We determined the kinetic characteristics of the cyanophyteSpirulina sp. LEB 18 and the chlorophyteScenedesmus obliquus LEB 22 and their capacities for CO2 fixation from the flue gas of a thermoelectric plant. The kinetic growth parameters of Spirulina increased when flue gas was used as the sole carbon source. At the end of cultivation, the biomass production of Spirulina sp. LEB 18 was 35% higher in the medium with flue gas compared to the Zarrouk medium, resulting in 5.7% CO2biofixation and a 24% reduction in flue gas CO2. Thus, the biofixation of CO2 from flue gas may be useful in helping to alleviate global warming. Key words: fossil fuel, microalgae, cyanophyte and chlorophyte.
Highlights
The burning of fossil fuels, especially coal, in thermoelectric power plants is problematic due to the emission of the greenhouse gas carbon dioxide (CO2) and the elevated temperature production of environmentally damaging sulfur and nitrogen oxides (SOx and NOx)
An increased concentration of CO2 leads to an increase in the specific growth rate, yield and biomass concentration (Maeda et al, 1995), and an increase in the maximum kinetic values was observed in the LEB 18 experiments with the addition of flue gas
We have reported similar lipid values in two previous studies, one using media supplemented with 120 g L-1 CO2, which produced a final biomass with a lipid concentration of 5.2% for LEB 18, 3.3% for LEB 22 and 4.6% for the Chlorella vulgaris strain LEB 106 (De Morais and Costa, 2007), and another employing media supplemented with 120 g L-1 CO2, 60 μL L-1 SO2 and 100 μL L-1 NO, which resulted in lipid values of 5.97% for LEB 18, 6.18% for LEB 22, 5.21% for LEB 106 and 5% for Synechococcus nidulans LEB 25 (Radmann and Costa, 2008)
Summary
The burning of fossil fuels, especially coal, in thermoelectric power plants is problematic due to the emission of the greenhouse gas carbon dioxide (CO2) and the elevated temperature production of environmentally damaging sulfur and nitrogen oxides (SOx and NOx). Microalgae use CO2 to multiply and produce biocompounds of interest, such as proteins, fatty acids and pigments. These microorganisms present antioxidant properties and are sources of carbohydrates, lipids, vitamins, essential amino acids and polyunsaturated fatty acids. The microalgae CO2biofixation mechanism is based on the ability of these microorganisms to perform photosynthesis but with higher fixation rates than those of higher plants. Another important feature is that gases that are emitted may be injected directly into microalgal cultivation through photobioreactor-coupled systems, while higher plants capture gases from the environment. Injection culture tanks may be used without the need to cool these gases because many microalgae have extremophile characteristics that allow them to withstand high temperatures (Pandey et al, 2014)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
