Extraction, purification, physicochemical properties, and spectroscopic stability of the R-Phycoerythrin from the seaweed Solieria filiformis cultivated in Ceara Coast/Brazil.

R-Phycoerythrin (R-PE) is a phycobiliprotein belonging to photosynthetic system of red seaweeds, which has a wide application in biotechnological and industrial products due to its antioxidant and spectroscopic properties. New renewable and sustainable sources of this pigment are still underreported. Therefore, this study aimed to extract, purify, and characterize the physicochemical properties of the R-PE from the red seaweed Solieria filiformis cultivated in the sea of Brazil Northeast. The R-PE was extracted in 0.025 M phosphate buffer, pH 6.5, and purified by protein precipitation followed by sequential ion exchange and molecular exclusion chromatographies, presenting a yield of 0.14 mg g ww, maximum purity index of 4.5, spectroscopic stability at -20 °C and 4 °C and molecular structure formed by protein bands of 18, 20 and 37 kDa. The R-PE was stable at a wide range of temperatures and pH and the circular dichroism showed protein secondary-structure composition of 60.19 % α-helices, 2.42 % β-sheets, and 37.39 % unordered structures, which were stable until 70 °C. Therefore, red seaweed S. filiformis is a promising renewable and sustainable source of high value phycobiliprotein that may promote the blue economy.