Cadmium Accumulation by a Citrobacter sp.: the Chemical Nature of the Accumulated Metal Precipitate and its Location on the Bacterial Cells

Abstract

Cells of a strain of a Citrobacter sp., pre-grown in cadmium-free continuous culture, accumulated cadmium extensively when resuspended in a buffer that contained Cd'+ and glycerol 2- phosphate. The accumulated compound was identified by X-ray microanalysis and magic angle spinning NMR analysis as cell-bound cadmium phosphate, probably CdHPOS. Its accumu- lation is consistent with the activity of a phosphatase, induced during pre-growth, that continues to function in the resuspended cells to liberate HPO$- from glycerol 2-phosphate. This anion then combines with Cd'+ to form insoluble cell-bound CdHPOj.