Extraction and Purification of Phycocyanin from Arthrophira platensis Microalgae Using a Green Solid‐Liquid Extraction Technology (RSLDE)

Spirulina is a blue alga belonging to the class of Cyanobacteria. This alga is characterized by a high content of phycocyanin (PC), a blue photosynthetic pigment belonging to the phycobiliprotein family. As natural dye, PC has a lot of industrial applications, in several fields such as the cosmetic, food, and textile sectors. It is also used in the biomedical field as a fluorescent marker. Anti-inflammatory, nephroprotective, and hepatoprotective properties are also reported, probably related to its antioxidant activity. However, the extraction of phycobiliproteins from cyanobacteria is a very complicated procedure due to the extreme resistance of the wall of the cellular aggregates that make up spirulina. In literature, several procedures have been used to cause rupture of cell envelopes, through cycles of freezing/thawing, sonication, and rupture of the cell wall with lysozyme. However, all these methods do not guarantee a high quality of the extract, due to the complexity of the mixture obtained. In order to improve the yield of PC and to reduce the extraction process time, in this work, the conventional extraction by sonication is compared with a green innovative extraction technique, the rapid solid liquid dynamic extraction (RSLDE). This technique can generate a pressure and a consequent depression on the matrix to be extracted. The final extract was immediately frozen at -20 degrees C and then lyophilized. UV-Vis spectrophotometric analysis and acrylamide gel electrophoresis are performed to evaluate the extraction efficiency and purity of PC.