Carbon Dioxide Sequestration by <I>Spirulina Platensis</I> in Photo-Bioreactors

Abstract

Spirulina platensis was cultivated at small scale in photobioreactors for CO 2 sequestration experiments carried out at different CO 2 concentrations within the range 0.5 to 10%, temperatures 10 to 40 o C and light intensities 60 to 200 μmol s -1 m -2. CO 2 sequestration effi ciency of achieved 99.9 %, specifi c growth rate, doubling time, rate of CO 2 sequestered into the algal cells and small changes of pH found for each batch experiment. Spirulina Platensis adapted to a novel nutrient solution was cultivated to explore its capacity to sequester CO 2 . The impacts CO 2 concentration, light intensity and temperature, on specifi c growth rate of Spirulina platensis and the adapted algae strain were described using empirical microbial growth kinetic models, Monod, Andrews and Mayo. The fi rst two models described properly the effects of CO 2 concentration and light intensity whereas the third the impact of temperature. Kinetic parameters from each model estimated optimum growth conditions of Spirulina platensis (2.5% CO 2 , 25 o C, 60 to 100 μmol s -1 m -2 ) and Spirulina platensis adapted (2.5% CO 2 , 25 o C, 100 μmol s -1 m -2 ) photoinhibition pedicted for extreme growth conditions (10% CO 2 , 40 o C, 200 μmol s -1 m -2 ) with both algal culture. Given comparable productivity between Spirulina Platensis and its adopted it would be worthwhile to select the algae strain adopted to specie to be used for CO 2 sequestration using photobioreactors at commercial scale and the production of value-added products.

Integrated Approach for Carbon Sequestration and Wastewater Treatment Using Algal–Bacterial Consortia: Opportunities and Challenges

“…14 - [39] Although different algal species are reported to withstand high concentrations of CO 2 , their enhanced growth and maximum biomass yield are largely observed only at CO 2 concentrations of 10-40%. Many studies indicate that the CO 2 concentration alone cannot be directly correlated to biomass productivity, but other factors such as the tolerance limit of algae to CO 2 and its utilization rate also play key roles in algal productivity [22,[40][41][42]. Furthermore, high photosynthetic efficiency of microalgae converts CO 2 to biomass rich in carbohydrates such as starch, cellulose, and various fermentable sugars via Calvin cycle [34,43], which is followed by metabolic pathways such as glycolysis and TCA cycle, resulting in lipid biosynthesis, stored as triacylglycerols and protein synthesis (Figure 1).…”

“…erance limit of algae to CO2 and its utilization rate also play key roles in algal productivity [22,[40][41][42]. Furthermore, high photosynthetic efficiency of microalgae converts CO2 to biomass rich in carbohydrates such as starch, cellulose, and various fermentable sugars via Calvin cycle [34,43], which is followed by metabolic pathways such as glycolysis and TCA cycle, resulting in lipid biosynthesis, stored as triacylglycerols and protein synthesis (Figure 1).…”

Impact of salinity on the kinetics of CO2 fixation by Spirulina platensis cultivated in semi-continuous photobioreactors

“…Therefore, the rate of CO2 biofixation per initial inoculation mass of microalgae can be determined by Eq. 5 rCO2 = RCO2/Xo (5) where RCO2 [gCO2 L -1 d -1 ] is the biofixation rate and rCO2[gCO2 g -1…”

“…By 2100, 26 billion tons of CO2 are estimated to be released into the atmosphere from anthropogenic sources 3 . Photosynthetic organisms such as microalgae species are potent producers of value-added bioactive compounds such as pigments, vitamins and long-chain polyunsaturated fatty acids, when grown under stress conditions can accumulate significant quantities of total lipids [4][5][6] . Recent studies indicated that improvements in culture conditions are needed to obtain adequate productivity of lipid, protein, carbohydrate content.…”

“…4,7 . The National Aeronautics and Space Administration (NASA) was the first institution to become interested in microalgae Spriulina for oxygen production, CO2 reduction and proposed it as one of the primary foods to be cultivated in a future bioregenerative life support system for long term manned space missions scenarios such as Moon and Mars bases [4][5][6] . The cyanobacterium Spirulina platensis (S. platensis) is commercially produced as a nutrient source in health food, feed and pharmaceutical industries, especially in developing countries 8 .…”