Protein purification of Arthrospira platensis using aqueous two-phase system composed of polyethylene glycol and potassium phosphate/sodium citrate

Aqueous two-phase systems (ATPS) stand out as an alternative technique for recovering and concentrating proteins. However, the study of ATPS to recover Arthrospira platensis protein is still poorly reported. This research used a sequential strategy of experimental design to evaluate the protein recovery from A. platensis protein extract using ATPS composed of polyethylene glycol (PEG: 1500, 4000, 6000, and 8000 Da) and saline solution (potassium phosphate and sodium citrate). The maximized conditions for A. platensis protein recovery were established by using 16% sodium citrate and 18% PEG 1500 Da, reaching 1.02 of purification factor and 75% protein recovery. Electrophoresis analysis showed protein bands between 5 and 15 kDa, characteristic size of phycobiliproteins. PEG and sodium citrate ATPS are a simple and low-cost alternative to the recovery A. platensis protein and show potential for industrial application.