Cadmium accumulation by a Citrobacter sp. immobilized on gel and solid supports: applicability to the treatment of liquid wastes containing heavy metal cations

Journal Article · Thu Jan 01 00:00:00 EST 1987 · Biotechnol. Bioeng.; (United States)

DOI:https://doi.org/10.1002/bit.260300110· OSTI ID:5663922

Macaskie, L E; Wates, J M; Dean, A C.R.

Polyacrylamide gel-immobilized cells of a Citrobacter sp. removed cadmium from flows supplemented with glycerol 2-phosphate, the metal uptake mechanism being mediated by the activity of a cell-bound phosphatase that precipitates liberated inorganic phosphate with heavy metals at the cell surface. The constraints of elevated flow rate and temperature were investigated and the results discussed in terms of the kinetics of immobilized enzymes. Loss in activity with respect to cadmium accumulation but not inorganic phosphate liberation was observed at acid pH and was attributed to the pH-dependent solubility of cadmium phosphate. Similarly high concentrations of chloride ions, and traces of cyanide inhibited cadmium uptake and this was attributed to the ability of these anions to complex heavy metals, especially the ability of CN/sup -/ to form complex anions with Cd/sup 2 +/. The data are discussed in terms of the known chemistry of chloride and cyanide-cadmium complexes and the relevance of these factors in the treatment of metal-containing liquid wastes is discussed. The cells immobilized in polyacrylamide provided a convenient small-scale laboratory model system. It was found that the Citrobacter sp. could be immobilized on glass supports with no chemical treatment or modification necessary. Such cells were also effective in metal accumulation and a prototype system more applicable to the treatment of metal-containing streams on a larger scale is described.

• Research Organization: Univ. of Oxford, England
• OSTI ID: 5663922
• Journal Information: Biotechnol. Bioeng.; (United States), Vol. 30:1
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
BACTERIA
IMMOBILIZED CELLS
CADMIUM
BIOLOGICAL ACCUMULATION
PHOSPHATASES
ENZYME ACTIVITY
CHLORIDES
CYANIDES
IMMOBILIZED ENZYMES
LIQUID WASTES
RESPONSE MODIFYING FACTORS
CHLORINE COMPOUNDS
ELEMENTS
ENZYMES
ESTERASES
HALIDES
HALOGEN COMPOUNDS
HYDROLASES
METALS
MICROORGANISMS
WASTES
560300* - Chemicals Metabolism & Toxicology