Characterization of the cadmium-binding capacity of Chlorella vulgaris

Algae and other aquatic plants possess the capacity to take up toxic trace metals from their environment, resulting in an internal concentration greater than those of the surrounding waters. This property has been exploited as a mean for treating industrial effluent containing metals before they are discharged, and to recover the bioavailable fraction of the metal. The advantages of using algae for such purpose are that algae are tolerant to elevated metal levels in their growth media. They grow autotrophically and have a large surface to volume ratio and the potential for genetic manipulation. Chlorella vulgaris is an unicellular Chlorophyceaen. Similar to other algae, Chlorella sp. has been demonstrated to develop tolerance to cadmium (Cd) polluted environment by synthesizing metal-binding proteins. In order to exploit the use of C. vulgaris as a tool for Cd-removal and recovery, it is necessary to characterize its metal-tolerance and its metal-binding capacity. In this study, the tolerance of the cells to elevated Cd in the environment, the biochemical basis of tolerance, as well as the organism's metal-binding capacity was examined.