臭化物, ヨウ化物イオン存在下におけるクロレラの水銀(II) : イオン還元反応

概要

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Hg^<2+> adsorbed to Chlorella cells in the presence of halide ions were not desorbed by the addition of EDTA or thiol compounds such as cysteine or glutathione. Rapid reduction of Hg^<2+> to metallic mercury (Hg^0) took place in the cells when the ion species [HgX_2]^0 (X=Br^- or I^-) was dominant, and this was the reason why adsorbed Hg^<2+> was not desorbed from the cells by the addition of extractants. Adsorption and reduction of Hg^<2+> decreased with increasing halide ion concentration, when the ion species [HgX_3]^- and [HgX_4]^<2-> became dominant. In the presence of [HgBr_2]^0 complex, the amount of Hg^0 volatilized increased with increasing Hg^<2+> added to the medium. A maximum amount of 125 μmol・g-cells^<-1> was recovered as volatilized Hg^0 at [HgBr_2]^0 at complex concentrations of 170〜250μmol・g-cells^<-1>. At 500μmol [HgBr_2]・g-cells^<-1>, no volatilization of Hg^0 was observed. In the presence of [HgI_2]^0 complex, only 60μmol・g-cells^<-1> was recovered as volatilized Hg^0 at 100μmol [HgI_2]・g-cells^<-1>. Reduction of Hg^<2+> was inhibited at a complex concentration of more than 150μmol [HgI_2]・g-cells^<-1>. Suppression of Hg^0 volatilization may be due to inhibition of the oxidation-reduction enzyme system in the call, and the [HgI_2]^0 complex seems to be more toxic to the cell.
社団法人日本生物工学会の論文
1995-01-25