CO2 enrichment: Enhancing antioxidant, antibacterial and anticancer activities in Arthrospira platensis

The effect of CO2 enrichment on the content of minerals, crude proteins, carbohydrate, and total polyphenols and flavonoids as well as antioxidant, cytotoxic and antibacterial activity of Arthrospira platensis were studied. A. platensis grown with CO2 enriched medium had less crude protein but more carbohydrate and phytochemical compounds. Increased calcium and iron contents were also obtained. CO2 seemed to increase polyphenols, flavonoids and tannins, which in turn increased antioxidant activities using the DPPH assay (IC50 = 1.64 mu g mL(-1)). Moreover, CO2 enrichment increased antibacterial activity, namely against E. coli and S. enterica. Cytotoxicity was increased with CO2, especially with the OVCAR (IC50 = 17.5 mu g mL(-1)) and MCF-7 (IC50 = 14.5 mu g mL(-1)) cell lines. GC-MS analysis showed that in CO2 free medium 12 bioactive compounds were found. The most abundant compounds were hexadecanoic acid, methyl ester and n-hexadecanoic acid. However in CO2 enriched medium results showed the presence of only 7 compounds. Therefore, the use of CO2 in the production of algae may have a positive environmental benefit to reduce the carbon pollution from the atmosphere and provide a better Spirulina production and quality.