Evaluation of extraction methods and purification by aqueous two-phase systems of phycocyanin from Anabaena variabilis and Nostoc sp

The main phycobiliprotein (PBP) found in cyanobacteria is phycocyanin (PC). The process of recovery is based on extraction followed by a purification stage. Among the methods of PBP extraction analyzed in this work, that is, freezing and thawing under sonication bath, vortex disruption with glass beads, maceration with pestle and mortar and ultrasonic homogenizer, the most efficient method was 5 freezing cycles (− 15 ± 1 °C) for 1.5 h and thawing (25 ± 1 °C) for 30 min in an ultrasonic bath, obtaining the highest PC concentrations of 32.87 μg mL −1 and 34.53 μg mL −1 and purities of 0.59 and 0.55, for Anabaena variabilis and Nostoc sp., respectively. In the purification by aqueous two-phase systems (ATPS), the systems of PEG (1500 and 4000) and two salts, potassium phosphate and sodium citrate, were evaluated using different volume ratios. The best system found was PEG 1500-potassium phosphate, in the proportion PEG, 10% (w/w) and salt, 15.9% (w/w), obtaining a recovery of 82.10%, partition coefficient of 5.73 and purity of 1.12 for the extract from Anabaena variabilis and recovery of 79.10%, partition coefficient of 6.36 and purity of 1.34 for the extract from Nostoc sp., both in adequate purity conditions for food grade.