•Mixture of protic ionic liquids (PILs): a promising solvent to extract phycobiliproteins.•Microwaves were used to disrupt microalgal cells to increase the extraction efficiency.•The power ...irradiation was the variable that most influenced the process.•The extracted biomolecules presented high antioxidant activity.•The recovery of the PILs allows its reuse to extract allophycocyanin.
Phycobiliproteins are potential molecules for use in various applications. Although phycobiliproteins extraction classical methods are reproducible and show good yields, they are generally time-consuming and require the use of high energy consumption and/or large volumes of solvent. Therefore, it is necessary the development of new eco-friendlier process by extraction techniques, permitting the transfer of the results obtained in laboratory scale for industrial. Then, microwave-assisted extraction using protic ionic liquid as solvent was proposed and optimized to extract phycobiliproteins from Arthrospira platensis in an efficient manner. The protic ionic liquids (PILs): 2-hydroxyethylammonium acetate (2-HEAA), 2-hydroxyethylammonium formate (2-HEAF), their equimolar mixture (2-HEAA + 2-HEAF), and the commercial ionic liquid 1-butyl-3-methylimidazolium chloride BmimCl were used as solvents, and sodium phosphate buffer as a control and the conditions of extraction were evaluated. The irradiation power was the most significant variable for the extraction process, and it showed a negative effect. The process conducted at 62 W and pH 7.0, using 2-HEAA + 2-HEAF and a solvent: biomass ratio of 10 mL∙g−1, showed the highest phycobiliproteins concentrations. The purity obtained for phycocyanin, allophycocyanin and phycoerythrin were 1.22, 1.03, and 0.71, respectively. The mixture of the PILs (2-HEAA + 2-HEAF) can be reused for three cycles for extraction of allophycocyanin. The extraction of phycobiliproteins using microwave and ionic liquids was efficient and the degree of purity and antioxidant activity achieved allows the application of these pigments in food and cosmetics.
The present study evaluated the use of a pressurized method to extract phycobiliproteins from the cyanobacterium
Arthrospira platensis
using sodium phosphate buffer as an extracting solution. ...Phycobiliprotein extracts were characterized and their antioxidant and anticancer activities (on different cancer cell lines) were determined. A high extraction yield was obtained when high pressure was used, without any alteration of the molecules’ biofunctionality. Maximum phycocyanin and allophycocyanin concentrations obtained (at 100 bar after 360 min) were 4.44 g L
−1
and 1.63 g L
−1
, respectively. The purity indexes of extract were 3.59 (A
615
/A
280
) for phycocyanin and 1.72 (A
652
/A
280
) for allophycocyanin. The purified phycobiliprotein extract showed high antioxidant activity, with 98% in the reduction of 2,2-diphenyl-1-picryl-hydrazil (DPPH) radicals and 100% in the chelation of ferrous ions, and it presented in vitro anticancer activity for HL60 leukemic cells.
