Research into the extraction of phycobiliprotein from Arthrospira platensis is currently ongoing. Most traditional methods of phycobiliprotein extraction include the use of organic solvents, which negatively affect the sustainability of the process. Ionic liquids (ILs) are a promising alternative for phycobiliprotein extraction due to their properties as green solvents. In the present work an imidazolium-based IL and sonication were studied for phycobiliprotein and carbohydrate extraction. A factorial experimental design was used to optimize the amount of extracted phycocyanin. The maximum extraction yield was achieved by using low biomass/solvent ratios combined with high IL/water ratios and sonication powers, and long operation times. The recovery of IL was studied under these conditions using a dialysis-based process to separate the IL from the extracted phycobiliproteins. The results reveal the possibility of using the recovered IL for seven consecutive extraction cycles with an acceptable phycocyanin extraction amount, from 75 mg g −1 (fresh IL) to 60 mg g −1 (7 cycles of reused IL). The use of [Emim] [EtSO 4 ] + ultrasound is a promising alternative for phycocyanin extraction, enhancing the results obtained with other IL in terms of extracted phycocyanin and the number of times the IL can be reused.

A new biorefinery from Arthrospira platensis was proposed to obtain phycocyanin (PC) and a biocrude by hydrothermal liquefaction (HTL). PC is a high-added-value phycobiliprotein widely used as a food colorant and in the nutraceutical and pharmaceutical industries. However, the use of conventional solvents in the extraction process and the purity grade of the extract are shortcomings in bioproduct production. PC was extracted using a reusable ionic liquid [EMIM][EtSO4], achieving a PC purity of the lowest commercial grade. Therefore, two downstream processes were applied: (1) dialysis + precipitation and (2) aqueous two-phase system (ATPS) + dialysis + precipitation. After the second purification process, the PC purity increased remarkably to reach the analytical grade for pharmaceutical and nutraceutical applications. The waste biomass (WB) obtained in the PC extraction was valorized by hydrothermal liquefaction (HTL) to produce a biocrude. The biocrude yield and composition remarkably enhanced using isopropanol at 350 °C as a cosolvent.