EFFECT OF URANIUM ON PIGMENT, LIPID AND SURFACE CHARACTERIZATION OF IMMOBILIZED ALGAE

Uranium is released from mining and milling facilities into the environment. It considered as a dangerous heavy metal because of its chemical toxicity rather than its radioactivity. Biosorption of heavy metals is an effective process not only for nuclear industry but also for cleaning of the environment. This work aimed to study the effect of uranium on immobilized Scenedesmus and Nostoc algae on the scale of pigments (chlorophyll a, b and carotenoids), lipids, and surface characterization. Uranium treatment resulted in inhibiting the biosynthesis of Chl a and Chl b, whereas the carotenoids content was stimulated as compared with control for both tested algae. The treated Scenedesmus and Nostoc samples resulted in increasing the total lipid content (10 and 7.4 %) as compared with their control (5.7 and 6.9 %) respectively. The morphological changes of immobilized Scenedesmus and Nostoc beads before and after uranium treatment were detected using energy dispersive X-ray spectroscopy (EDX) and scanning electron microscopy (SEM). Appearance of uranium peak on EDX spectra confirmed the uranium biosorption by the algal beads. Also, SEM images showed a rough and dynamic nature of algal beads compared to the smooth and uniform one of the untreated samples.