Isolation and antiradical activity of phycobiliprotein compounds from Chlorellapyrinoidosa

Chlorella pyrinoidosa is known to have the highest protein content compared to other microalgae. One of the proteins which has the potential to be developed as a food supplement is phycobiliprotein. The objective of this study was to isolate and determine the antiradical activity of phycobiliprotein compounds in Chlorella pyrinoidosa. The extraction process was carried out using the freeze-thawing method. Aqua pro injection solvent was added to the microalgae biomass, and the mixture was vortexed for 20 s. The pellets obtained were frozen for 24 hrs at -4°C and then thawed at 25°C. After the sample melted, the separation process was carried out by centrifugation at a speed of 3,500 rpm for 15 mins and purified using a cellulose membrane dialysis tube with weight molecular cut-off 12-14 kDa for 12 hrs at 4°C. The supernatant was then freeze-dried. The phycobiliprotein was characterized by Fourier Transform Infrared (FTIR) spectrophotometer to determine the functional groups, SEM (Scanning Electron Microscopy) to determine the topography of the surface of the specimen, and the ninhydrin test to qualitatively prove the presence of amino acids or proteins in a sample. Chlorella pyrinoidosa contained phycobiliprotein compounds with the characteristics of having the functional groups of O-H, N-H and C=O, the shape of tiny granules that were unevenly distributed on the surface, and some cracks and clusters which were quite diverse, with an average diameter of 10 µm. Phycobiliprotein in Chlorella pyrinoidosa had moderate antiradical activity with an IC50 value of 141.254 ppm using the 2,2- Azinobis(3-Ethylbenzothiazoline-6-Sulfonic Acid) (ABTS) method. Because of its antioxidant activity, the phycobiliprotein compound in Chlorella pyrinoidosa has the potential to be used as a food supplement.