Cadmium uptake by selected Microalgae
B.D.Jimenez, I.V. Angeles, C.J. Monte and B.V. Ocampos
Department of Biological Sciences, MSU-IIT, Iligan City
e-mail: bdjimenez7@gmail.com
Cadmium uptake in-vitro by three selected microalgae: Chlorella sp. Chlorophyceae), Skeletonema sp. (Bacillarophyceae) and Spirulina sp. (Cyanophyceae) was conducted. The mode of uptake and possible effect on chlorophyll pigments were also noted.
Different concentration levels of the metals (0.05ppm, 5ppm and 10ppm) in three replicates were introduced at mid-log phase of the algal culture in a complete randomized design. Cadmium was recovered in water, supernatant and pellets and analyzed by atomic absorption spectroscopy for mode of uptake.
Cadmium detected in water indicated the remaining cadmium not taken up by the algae. Those detected in the supernatant and pellets represented extracellular and intracellular uptake, respectively.
Skeletonema sp. was the most efficient in sequestering the metal (87%) from the medium extracellularly.
Chlorella and Spirulina were efficient in bioaccumulation of the metal in their cytoplasm at higher concentrations and adsorbed the metal in their cell wall at lower concentrations.
Chlorophyll pigments were not affected at concentrations of 0.05ppm but showed deleterious effect at 10ppm. Highest total chlorophyll was obtained at 0.05ppm. Chlorophyll a, the most prominent pigment in photosynthesis decreased with cadmium concentration.
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