Characterization of phycocyanin from Spirulina fusiformis and its thermal stability

Microalgae have some pigments which are potential to be used as functional colorant for foods and cosmetics industries. Here, Spirulina fusiformis is one of the major sources of a blue pigment phycocyanin which has commercial and biotechnological value for biomedical research, as well as a natural colorant for food and cosmetic industries. This study aims at investigating the characteristic of isolated C-phycocyanin from Spirulina fusiformis and its stability under different temperature. A food grade phycocyanin with purity of 2.0 (A(620)/A(280)) was obtained successfully from Spirulina fusiformis cultured in seawater-based modified medium and purified by ammonium sulfate precipitation. No significant changes were observed in the spectrum absorbance of C-phycocyanin at temperature up to 60 degrees C over 30 minutes of incubation, and was observed to significantly denaturation at 70 degrees C and higher temperature. Incubation of the pigment at relatively high temperature resulted in a decrease in the spectrum intensities of the C-phycocyanin in a temperature-dependent manner. Taken together, our results suggest that the optimal condition for preserving the stability of food grade phycocyanin isolated from Spirulina fusiformis is taking it at low temperature.