BIOACCUMULATION OF ANTIMONY BY CHLORELLA-VULGARIS AND THE ASSOCIATIONMODE OF ANTIMONY IN THE CELL

The bioaccumulation and excretion of antimony by the freshwater alga C hlorella vulgaris, which had been isolated from an arsenic-polluted en vironment, are described. When this alga was cultured in a medium cont aining 50 mu g cm(-3) of antimony(III) for 14 days, it was found that Chlorella vulgaris bioaccumulated antimony at concentrations up to 12 000 mu g Sb g(-1) dry wt after six days' incubation. The antimony conc entration in Chlorella vulgaris decreased from 2570 to 1610 mu g Sb g( -1) dry wt after the cells were transferred to an antimony-free medium . We found that the excreted antimony consists of 40% antimony(V) and 60% antimony(III). This means that the highly toxic antimony(III) was converted to the less toxic antimony (V) by the living organism. Antim ony accumulated in living Chlorella vulgaris cells was solvent-fractio nated with chloroform/methanol (2:1), and the extract residue was frac tionated with 1% sodium dodecyl sulfate (SDS). Gel-filtration chromato graphy of the solubilized part showed that antimony was combined with proteins whose molecular weight was around 4 x 10(4) in the antimony-a ccumulated living cells. (C) 1997 by John Wiley & Sons, Ltd.