Extraction of phycocyanin from Spirulina using Deep Eutectic Solvent Liquid Biphasic System

Phycocyanin (PC) is an intracellular protein produced in Spirulina sp. and is widely used as a natural dye in the cosmetic, food, and supplements industries. But the extraction of phycocyanin was limit by properties of proteins and technologies. Here, deep eutectic solvents were found to be an effective method of extraction, circumventing any usage of harmful organic solvents. In particular, we explored the use of DES/K2HPO4 liquid biphasic system (LBS) as the extraction medium, where the extracted PC from the cell in bottom phosphate aqueous phase is selectively transferred to the top DES phase. Among the different DES, the ChCl-Urea and ChCl-Glycerol showed the highest extraction efficiencies and yields, but the Glycerol synthesized DES has bad mass diffusion problems. Through continuous single-factor optimization, we finally achieved the best extraction efficiency and yield of 94.2% and 92.0%, respectively, using ChCl-Urea/K2HPO4. This proposed solution has the potential to be produced on a large scale and is environmentally friendly for the extraction of phycocyanin.