Application of aqueous biphasic systems based on pluronic copolymer and deep eutectic solvent to achieve purified C phycocyanin

The idea of isolating C-phycocyanin from Spirulina platensis microalgae to be used as a valuable protein has a long history, so that today, with the advancement of science and application of various technologies, the isolation of this protein occurred by one of the most important processes. C-phycocyanin has multiple applications in pharmaceutical, cosmetic and food industries as an additive and natural dye. In this research, the aqueous two-phase system (ATPS) based on block copolymers and deep eutectic solvents (DES) was used for C-phycocyanin purification and their phase behavior was evaluated. This method can be used as an efficient and cost-effective method for the extraction and purification of C-phycocyanin compared to other purifying processes such as ion exchange chromatography. After that, the effects of parameters such as copolymer structure, DES type, DES concentration, copolymer concentration and system temperature in the ATPS containing copolymer/DES were studied for C-phycocyanin purification. The results showed that the aqueous biphasic system containing Pluronic 10R5 and ChCl-Glu is the most suitable system for obtaining the food grade C-phycocyanin. The purity index was 2.7 obtained at 25% copolymer concentration, 35% ChCl-Glu concentration and at 35 °C. At these conditions, a 97% C-phycocyanin extraction efficiency was achieved without any loss of stability. After that, the ultrafiltration process was used to increase the purity of C-phycocyanin from 2.7 to 4.8. Pluronic 10R5 was recovered during the extraction process at a temperature above 57 ºC. Finally, the purity of C phycocyanin was confirmed by using SDS-PAGE analysis.