A COMPARISON OF PHOTOPIGMENTS AND CHARACTERIZATION OF PHYCOCYANIN IN CYANOBACTERIA ORIGINATING FROM DIFFERENT HABITATS

Abstract

Cyanobacterial diversity under environmental extremes led us to screen Chl a, carotenoids d and phycocyanin in cyanobacteria Nostoc muscorm (mesophile), Mastigocladus laminosus (thermophile) and Nostoc 593 (Antarctic) grown at 30, 40 and 20°C, respectively. Maximum amount of Chl awas recorded in N muscorum (6.34 µg mg^-1 dry weight) over Nostoc 593 (6.29 µg) and M. laminosus (4.62 µg).While for carotenoids, the sequence changed to Nostoc 593 (4.35 µg) > M. laminosus (4.08 µg) > N. muscorum (2.48 µg). Phycocyanin followed the same pattern as carotenoids. Maximum amount of phycocyanin was recorded in   Nostoc 593 with 154 µg over M. laminosus with 84.7 µg and N. muscorum with 64.52 µg mg^-1dry wt. Phycocyanin was purified to homogeneity and confirmed further by SDS-PAGE. Pure phycocyanin yielded two subunits with apparent molecular mass of 14 and 15 kDa each. It is anticipated that cyanobacteria may be the ideal resource of such antioxidant proteins from the biotechnological viewpoint.