Extracting and Purifying Pigment R-phycoerythrin from the Red alga Mastocarpus Stellatus

Abstract

R-phycoerythrin (R-PE) is one of the three phycobiliproteins which are extensively employed as fluorescent probes, natural colorant for the production of food and cosmetics and it is prepared from red macroalgae. Mastocarpus stellatus is known as a rich source of carrageenan and protein. In this study, the R-PE in the red seaweed Mastocarpus stellatus was extracted in 20 mM phosphate buffer (pH 7.1) and purified by DEAE sepharose Fast Flow chromatography with a three-step increase in ionic strength. The NaCl elution step allowed the crude extracts to be separated into three fractions: AE-150, AE-200 and AE-1000. The quality and quantity of R-PE recovery were indicated different methods to monitor each fraction obtained, such as spectrophotometric indicators, gel filtration. The A565/A280 ratio (Purity Index, PI) obtained after the purification step was 1.91 in the fraction AE-200 and this value was higher 14 times than the PI of the crude extract and about 8 times than the sample precipitation by ammonium sulfate saturation of 85%.