摘要：The uptake of cadmium (Cd) and the production of cadmium binding protein (Cd-BP) in Chlorella ellipsoidea were examined. To the medium in which chlorella was growing to the stationary phase CdCl2 (2 mg Cd/l) was added and the cultivation in the presence of CdCl2 was run for 0-120 h under light intensity of 4 kLx at 25°C with bubbling 5% CO2 gas. An aliquot of chlorella was harvested every 24 h from the culture medium and its Cd concentration was estimated by atomic absorption spectrophotometry. Cadmium taken up by the cells increased with increasing the cultivation period and the concentration of CdCl2 added to the medium. Cadmium in the cells was detected in the cytosol fraction and estimated to bind to the protein. The Cd-BP produced in the cytosol was eluted at the position of Ve/Vo 2.3 on a Sephadex G-75 column. The production of Cd-BP was found to be dependent on the concentration of Cd in chlorella cells. Moreover, the production of Cd-BP was not stimulated by ZnSO4 (5.36×10-5 mol in the medium). Cadmium bound to the protein was partly substituted by Cu when 1.07×10-5 mol CuSO4 was added to the medium.
