Enzyme-Assisted Method for Phycobiliproteins Extraction from Porphyra and Evaluation of Their Bioactivity

Abstract

Due to the poor protein availability of algae in their unprocessed form, development of extraction methods for phycobiliproteins is of great significance. This study aimed to extract phycoerythrin (PE) and phycocyanin (PC) from Porphyra via bacterial enzymatic hydrolysis and to evaluate their bioactivity. To induce enzyme production, Porphyra powder was added into the culture medium of two marine bacterial strains. The pH and enzyme activity of the cultured supernatant, namely crude enzyme solution, were significantly raised. For PE and PC extraction, Porphyra were incubated within crude enzyme solution with homogenization and ultrasonication followed by ultrafiltration process. After distinguishing by fast performance liquid chromatography (FPLC), three major fractions were observed and identified as R-PE, R-PC and small molecular PE by high-performance liquid chromatography (HPLC) and polyacrylamide gel electrophoresis (PAGE) analysis. With respect to bioactivity, these three fractions exhibited free radical scavenging and antioxidant activities in a various degree. In addition, the angiotensin-converting-enzyme (ACE) inhibitory activity of both R-PE and R-PC fractions was observed in a concentration-dependent manner. Taken together, the employed process of bacterial enzymatic hydrolysis is suggested to be a feasible method to obtain PE and PC from Porphyra without limiting their bioactivity.