Phycoerythrin productivity and diversity from five red macroalgae

Five red algae, Agardhiella subulata, Gracilariopsis longissima, Gracilaria vermiculophylla, Polysiphonia morrowii, and Pyropia elongata were sampled in winter for the extraction of phycoerythrin. The extracted phycoerythrin molecules were compared with the commercial phycoerythrin to determine the intrinsic fluorescence characteristics of the single pigments. An improved selective method for phycoerythrin extraction was set up for routinary investigation. The use of the mortar and pestle method for tissue homogenization with a freeze-thawing cycle allowed a simple and complete homogenization of the red algae. The extraction of phycoerythrin with diluted EDTA solutions (1 mM) at pH 9 enabled a selective and easy extraction of the pigment with 95–98% extraction efficiency. The way pH affected the phycoerythrin, phycocyanin, and allophycocyanin selective extraction was also evaluated. The 3D fingerprint of each pigment was recorded, and a comparison of different phycoerythrin spectra was performed by fluorescence spectroscopy highlighting differences in A. subulata and P. morrowii phycoerythrins in comparison with commercial standards purified from Pyropia. The productivity and the advantages of phycoerythrin that was extracted from unattached red algal species are discussed.