Abstract: Three kinds of wall breaking methods were used to release phycoerythrin (PE) from Porphyra yezoensis. The extraction ratio and purification standard of PE were used to evaluate their effects. The results showed that the freezing-thawing method has low extraction ratio, while the swelling method has the highest extraction ratio and purification standard of PE among the three methods. However, its work time is too long. Hence, it proved that the pulsed ultrasonic method is the best wall breaking method of Porphyra yezoensis. When a 2000 ml of solution with a 30 mg/ml of ratio of material vs solvent was treated for 60 min at 20℃ with the pulsed ultrasound a 800 W of power and a pulse of 2s for run and 3s for interim, the optimal wall breaking effect is obtained, resulting in a 3.249% of extraction ratio of Phycoerythrin and a 0.365 (OD561/OD280) of purification standard. The advantages of ultrasonic method gives short treatment time and large processing yield.

Key words: Porphyra yezoensis, phycoerythrin, wall breaking method, extraction