Fatemeh Heidari, Zeinab Shariatmadari* and Hossein Riahi Pages 407 - 414 ( 8 )
Background: Microalgae are the source of various compounds with high potentials for being used in different industries. The production of such compounds can be raised under extreme conditions. In the present study, four cyanobacteria and one coccoid green alga were examined which were isolated from hot springs in high background radiation areas in Ramsar, a city in the north of Iran.Methods: Cadmium adsorption from aqueous solution, response towards cadmium stress, antioxidant activity, total phenolic compound and drought tolerance were investigated in these microalgae. Results: The results showed that these extremophile microalgae contain valuable biological compounds which can be useful in remediation of heavy metals from contaminated water and soils and pharmaceu-tical applications. The unicellular cyanobacterium, Chroococidiopsis thermalis IBRC-M50002, was the best strain with the highest biological activity in various testes such as cadmium adsorption (225 mg g-1), cadmium tolerance stress (100 mg ml-1), antioxidant activity (IC50= 18 μg mg-1) and total phenol content (100 μg ml-1). The coccoid green algae Grasiella emersonii IBRC-M50001, also exhibited sig-nificant antioxidant activity (IC50=10 μg mg-1) and total phenol compound (116 μg ml-1), but its cad-mium adsorption, tolerance at cadmium stress and desiccation were lower than Chroococidiopsis ther-malis. Conclusion: HBRAs microalgae, isolated from extreme conditions, are useful microorganisms for the production of bioactive substances and natural antioxidants. In other words, they exhibited high capacity to be used in pharmaceutical, industrial and commercial applications.
Antioxidant activity, cadmium adsorption, extremophile microalgae, High Background Radiation Areas (HBRAs).
Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, G.C.Tehran, Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, G.C.Tehran, Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, G.C.Tehran