Utilization of Carbon Dioxide from Coal-Firing Flue Gas for Cultivation of Spirulina platensis

Abstract

CO2 emission from burning coal has been used as a carbon source for growing Cyanobacterium Spirulina platensis in order to minimize the cost of biomass production, and currently to carry out CO2 bioremediation. This article presents the results of feeding S. platensis in laboratory conditions with 2 formulas including Pure CO2 and Flue gas CO2 upon using modified Zarrouk’s medium with 1.6 g / L NaHCO3 and 2g / L Na2CO3. Pure CO2 with 1.2% concentrations taken from 99% vol of industrial CO2 and CO2 gas (1.2%) received from the flue gas through the Modular system of Exhausted Gas Treatment (MEGT). Growth of the Cyanobacterium using CO2 - Flue gas is equivalent to CO2 -Pure. On this basis, S. platensis has been cultivated outdoor in an 25 m2 pond using CO2 gas (1.2%) from the tunnel brick factory emissions after suitable cleaning. The experiment in an outdoor pond system of 25 m2 indicated that the yield of biomass is of 10g/m2d with high-protein content (62.58 ± 2.34%) and fatty acids of high nutritional value (8.72 ± 0.14%), such as Omega - 6 and Omega - 3 reaching 14.74 ± 0.42% and 26.05 ± 0.64% of total fatty acid content, respectively. The quality of Spirulina cultured by CO2 gas meets the requirements for functional foods according to Vietnam national food standards. The article also presents the results of biomass productivity and chemical composition of the Cyanobacterium in different culture conditions.