Extraction and purification of B-phycoerythrin from the red microalga Rhodosorus marinus

A description is given of the purification of B-phycoerythrin (B-PE) from the red microalga Rhodosorus marinus. Initially, phycobiliproteins were released from the microalgal cells by manual cellular fragmentation and sonication. B-PE was extracted with ammonium sulfate precipitation, and purified by anionic and size exclusion chromatography. Its purity was tested using indexes and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Spectroscopic characterization of B-PE was performed by UV-visible spectroscopy, fluorescence spectroscopy, and circular dichroism. Rhodosorus marinus showed three types of phycobiliproteins: phycoerythrin, phycocyanin, and allophycocyanin. The purified B-PE showed a purity ratio (A(545)/A(280)) of 4.8, characteristic peaks at 540 and 562 nm with a shoulder at 498 nm, fluorescence emission maximum at 578 nm, and a secondary structure almost stable with pH changes. B-PE was found to be the predominant pigment in R. marinus and this red microalga could be a viable option for the recovery of this chromoprotein.