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Electrophoretic analysis of cyanide depletion by Pseudomonas alcaligenes

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Abstract

Bacterial-facilitated depletion of cyanide is under development for remediation of heap leach operations in the gold mining industry. Capillary electrophoresis was found to be a powerful tool for quantifying cyanide depletion. Changes in cyanide concentration in aqueous suspensions of Pseudomonas alcaligenes bacteria and cyanide at elevated pH were easily monitored by capillary electrophoresis. The resulting data can be used to study rates of cyanide depletion by this strain of bacteria. Concentrations of these bacteria at 10(5) cells/mL were found to reduce cyanide from 100 ppm to less than 8 ppm in four days. In addition, other ions of interest in cyanide metabolism, such as formate, can be simultaneously analyzed. Direct UV detection of cyanide at 192 nm further simplifies the analytical method for these ions.

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... Biological degradation of cyanide in which CN − is converted to CO 2 , NH 3 , and OH − by bacteria, when appropriate, is considered the most cost-effective method in cyanide detoxification and has been used in cyanide detoxification of heap leaches containing more than 1.2 million t (Mosher and Figueroa 1996 ). Concentrations of 10 5 cells of Pseudomonas alcaligenes/mL can reduce cyanide from 100 to <8 mg/L in 4 d at elevated pH (Zaugg et al. 1997). Strains of Escherichia coli isolated from gold extraction liquids metabolically degrade cyanide at concentrations up to 50 mg HCN/L in the presence of a glucose–cyanide complex (Figueira et al. 1996). ...
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