Extraction, purification and evaluation of antimicrobial and antioxidant properties of phycoerythrin from terrestrial cyanobacterium Nostoc sp. FA1

Phycoerythrin (PE( found in cyanobacteria are natural dyes which have shown potential therapeutic properties. Nowadays, substitution of artificial oxidants with harmless natural antioxidants is crucial. Hence, the present study was focused on purification process of PE from a soil strain of Nostoc sp.FA1 and evaluating its antioxidant and antimicrobial activity.    

Extraction and purification of PE was performed in four stages of preparation of crude extract, 65% ammonium sulfate precipitation, dialysis and anion exchange chromatography. Subsequently, antioxidant and antimicrobial activity was determined by nitric oxide scavenging and paper disk diffusion method respectively.    

It was found that concentration and purity of PE were increased after each purification step by almost four times (from 1.5 to 6.22). PE had the strongest inhibitory activity against Bacillus subtilis(10.5 ± 0.28) and Candida albilancs (10.98 ± 0.006). In addition, the results of antioxidant surveys showed that PE is a potent free radical scavenger and this activity increased significantly with the increasing pigment concentration.  

 The results of this study can be the basis for the introduction of natural edible pigments of soil cyanobacteria with antioxidant and antimicrobial properties that can be used in food and pharmaceutical industries.