A Novel Three-Step Extraction Strategy for High-Value Products from Red Algae Porphyridium purpureum.

Tao Li,Chulin Li,Zishuo Chen,Jin Xu,Hualian Wu,Wenzhou Xiang,Houbo Wu,Weinan Wang

doi:10.3390/foods10092164

Abstract

The microalga Porphyridium accumulates high-value compounds such as phycoerythrin, polyunsaturated fatty acids, and polysaccharides, and thus, the extraction of these compounds could significantly expand the value of Porphyridium biomass. In the present study, a novel fractional extraction strategy based on the characteristics of these compounds was established using cold water, 95% ethanol, and hot water. The yield of phycoerythrin, lipids, and polysaccharides was 63.3, 74.3, and 75.2%, respectively. The phycoerythrin exhibited excellent fluorescence characteristics but had low purity. The crude lipid was dark with poor fluidity. Digalactosyldiacylglycerol and sulphoquinovosyldiacylglycerol containing C20:5 and C20:4 were the most abundant glycerolipids, while glucose, xylose, and galactose constituted the intracellular polysaccharides that had covalently bound to proteins (8.01%), uronic acid (4.13%), and sulfate (8.31%). Compared with polysaccharides and crude lipids, crude phycoerythrin showed the best antioxidant activity. Overall, the three-step fractional extraction process was feasible for Porphyridium; however, further purification is necessary for downstream applications.

Highlights

Porphyridium, a unicellular microalga that belongs to phylum Rhodophyta, classBangioideae, order Bangiales, and family Porphyridiaceae, live in seawater, brackish water, freshwater, and moist soil environments [1]
The polyunsaturated fatty acids (PUFAs) and intracellular polysaccharides still remain in the algal residue
A sequential extraction process based on the characteristics of phycoerythrin, PUFAs, and polysaccharide, was established using cold water, 95% ethanol, and hot water

Summary

Introduction

Porphyridium, a unicellular microalga that belongs to phylum Rhodophyta, classBangioideae, order Bangiales, and family Porphyridiaceae, live in seawater, brackish water, freshwater, and moist soil environments [1]. Of the nine documented species of Porphyridium, Porphyridium purpureum ( called Porphyridium cruentum) has been widely studied as a model species. This red alga can accumulate high-value compounds, such as B-phycoerythrin, polyunsaturated fatty acids (PUFAs), and intracellular polysaccharides, the potential feedstock for food, cosmetics, and drugs [2]. No extraction method has been reported so far for the simultaneous extraction of these three high-value compounds from Porphyridium biomass. Phycoerythrin, the major photosynthetic pigment in P. purpureum, exhibits several biological activities, including anti-oxidation, anti-tumor, and immunity enhancement [1]. Phycoerythrin is widely acknowledged as a rare orange-red pigment in nature due to its strong coloration and antioxidant activity similar to blue phycocyanin from

Methods

Results

Discussion

Conclusion