Effect of physical and culture conditions on uptake of cadmium by Chlorella pyrenoidosa

Abstract

The effects of pH, temperature, concentrations of Cd2+ and P43-, and density of algal suspension on the uptake of cadmium by C.pyrenoidosa were studied. Uptake occurred in at least two phases: fast (8 min) and slow (24 h). The slow uptake was dependent on pH (greater at pH 8.0 than 6.5) and temperature (faster at 25 than 4�C) whereas the fast uptake was not. Both phases of uptake were affected by the density of the algal suspension. Dependence on the concentration of Cd2+, at pH 8.0, was limited by the concentration of PO43- and also possibly by the concentration of CO3-2. Results were generally consistent with the model of initial ion-exchange uptake onto the cell wall and much slower transport across the cell membrane.