title: Preparative purification of B-phycoerythrin from the microalga Porphyridium cruentum by expanded-bed adsorption chromatography.
abstract: B-Phycoerythrin (B-PE) is a major light-harvesting pigment of microalgae. Due to its high fluorescence efficiency and its intense and unique pink color, it is widely used as a fluorescent probe and analytical reagent as well as being employed as a natural dye in foods and cosmetics. Tedious methodologies for B-PE purification have been published. In this work we present a new, fast, preparative and scaleable two-step chromatographic method for B-PE purification from the red microalga Porphyridium cruentum. Initially, phycobiliproteins were released from the microalga cells by osmotic shock and captured by applying the centrifuged cell suspension to a column containing 74 ml Streamline-DEAE equilibrated with 50 mM acetic acid-sodium acetate buffer, pH 5.5, using expanded-bed adsorption chromatography at an upward flow of 200 cm h(-1). After adsorption, washing was carried out in the expanded-bed mode. Having removed unbound proteins and cellular debris, the bed was allowed to sediment and a B-PE-rich solution was eluted with a downward flow of the same 250 mM buffer. In order to obtain pure B-PE, we utilized conventional ion-exchange chromatography with a column of DEAE-cellulose loaded directly with the eluate from Streamline-DEAE and developed using a discontinuous gradient of acetic acid-sodium acetate buffer, pH 5.5. With this new methodology, 66% of B-PE contained in the biomass of the microalgae was recovered, a value significantly higher than those obtained following other methodologies. The B-PE purity was tested using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and spectroscopic characterization.
authors.affiliation: Department of Physical and Analytical Chemistry, Jaén University, E.U.P. of Linares, 23700, Linares, Spain.
authors.forename: Ruperto
authors.initials: R
authors.lastname: Bermejo
authors.forename: F Gabriel
authors.initials: FG
authors.lastname: Acién
authors.forename: M José
authors.initials: MJ
authors.lastname: Ibáñez
authors.forename: José M
authors.initials: JM
authors.lastname: Fernández
authors.forename: Emilio
authors.initials: E
authors.lastname: Molina
authors.forename: José M
authors.initials: JM
authors.lastname: Alvarez-Pez
mesh_terms: D000327:Adsorption; D002852:Chromatography, Ion Exchange / Q000379:methods*; D004591:Electrophoresis, Polyacrylamide Gel; D010799:Phycoerythrin / Q000302:isolation & purification*; D044665:Porphyridium / Q000737:chemistry*
chemical_list: D010799:Phycoerythrin