Open AccessDifferential pulse polarography: a method of directly measuring uptake of metal ions by live bacteria without separation of biomass and medium
Author(s) -
Savvaidis Ioannis,
Hughes Martin N.,
Poole Robert K.
Publication year - 1992
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1992.tb05256.x
Subject(s) - polarography , metal , metal ions in aqueous solution , chemistry , analytical chemistry (journal) , pulse (music) , ion , chromatography , inorganic chemistry , voltage , physics , organic chemistry , quantum mechanics
The technique of differential pulse polarography is shown here for the first time to be applicable to monitoring directly the uptake of metal ions from solution by live bacteria in the chamber of the polarograph. The potential at which the polarographic current peak is observed is characteristic of the metal, whereas peak height is proportional to metal concentration. Adding solutions of Cd(II) or Zn(II) to a suspension of Pseudomonas cepacia in 50 mM Hepes buffer (pH 7.4) in the chamber gave polarographic peaks of lower amplitude than those observed when these metal solutions were added to buffer alone, due to metal binding or uptake by cells. Langmuir plots gave binding capacities of 0.13 and 0.20 mmol metal (Dd or Zn, respectively) per g (dry weight) biomass. Ni(II) uptake was biphasic. Metal uptake increased with pH. The value of polarography for rapid assessment of metal removal by cells and the ability to measure uptake from multi‐metal solutions is demonstrated.