Abstract：Phycobiliproteins are a family of natural pigment proteins with wide applications and promising market prospects, but their extraction and purification is difficult. Extraction optimization plays an important role in the recovery and purification of the final phycobiliproteins. In this paper, ammonium sulfate saturation, precipitation frequency, ammonium sulfate fractionation are employed to extract R-phycoerythrin and R-phycocyanin from marine red alga Polysiphonia urceolata. The results show that the yields of RPE and RPC are increased with increasing ammonium sulfate saturation. At 60% saturation, their yields reach the highest, up to 91.59% and 97.98%, respectively. 20% saturation could still precipitate 47.3% of RPE and 24.8% of RPC. The purity of RPE is decreased with increasing salt concentration. However, RPC purity is increased with increasing ammonium sulfate saturation, at 45% saturation, the purity reaches the highest, and then slowly decreases as the saturation further increases. During the saturation of 20%~40%, the recovery ratio of RPE and RPC increases with increasing salt concentration; at 40%, the ratio reaches the highest, then is stabilized above 40%. The twice ammonium sulfate precipitation is better than once for RPE and RPC extraction, their yields fall, but their purity is increased. Ammonium sulfate fractionation could significantly increase the purity of RPE and RPC, by 122.42% and 18.67%, as compared to one-step salting, but their yield is decreased significantly. So 60% saturation of ammonium sulfate is suitable for extraction of RPE and RPC from Polysiphonia urceolata, twice salting and two-step fractionation are good for purity increasing, but the first fractionation saturation of ammonium sulfate should be below 20%. This study can be a help for the phycobiliproteins purification.
2010, Vol. 28 
