Remobilization of Heavy Metals Retained as Oxyhydroxides or Silicates by <i>Bacillus subtilis</i> Cells

Abstract

The stability of heavy metals bound as either silicates or oxyhydroxides by the surfaces of Bacillus subtilis with changes in pH and presence of competing cations and EDTA was studied. Wall-bound silicate was very stable. Of all conditions, a pH of 3.0 (by HNO(3)) promoted the greatest release of Cd (87% [wt/wt]), Pb (77%), or Cu (54%). Bacterial Pb resisted extraction by EDTA, and Cd that was included in bacterial-silicates proved difficult to remobilize.