Antioxidants from carbon dioxide fixing Chlorella sorokiniana

Chlorella sorokiniana H-84, which has tolerance to high temperatures and high concentrations of CO2, has been isolated from a hot spring in Japan. Large-scale culturing of C. sorokiniana was carried out in air containing 10% CO2. Analysis of the biomass shows that protein, carbohydrate and lipids comprised 68.5, 11.9 and 10.0% of dry matter, respectively. The total carotenoids comprised 0.69% dry matter. The lutein and beta -carotene contents were 4300 and 600 mug g(-1) dry weight, respectively. The alpha -tocopherol content was 112 mug g(-1) dry weight. These carotenoids and alpha -tocopherol are known to possess radical scavenging activity. Two fractions with radical scavenging activity were isolated from the aqueous extract of C. sorokiniana H-84. The extract showed several single peaks by reversed phase HPLC analysis and two of them had molecular weights of 710 and 1286, respectively.