Biogenic production of cyanide and its application to gold recovery |
| |
Authors: | S C Campbell G J Olson T R Clark G McFeters |
| |
Institution: | (1) The Center for Biofilm Engineering and Microbiology Department, Montana State University, Bozeman, MT,;(2) Little Bear Laboratories, Inc., Golden, CO , |
| |
Abstract: | Chromobacterium violaceum is a cyanogenic (cyanide-producing) microorganism. Cyanide is used on an industrial scale to complex and recover gold from
ores or concentrates of ores bearing the precious metal. A potentially useful approach in gold mining operations could be
to produce cyanide biologically in relatively small quantities at the ore surface. In this study, C. violaceum grown in nutrient broth formed a biofilm and could complex and solubilize 100% of the gold on glass test slides within 4–7
days. Approximately 50% of the cyanide-recoverable gold could be mobilized from a biooxidized sulfidic-ore concentrate. Complexation
of cyanide in solution by gold appeared to have a beneficial effect on cell growth — viable cell counts were nearly two orders
of magnitude greater in the presence of gold-coated slides or biooxidized ore substrates than in their absence. C. violaceum was cyanogenic when grown in alternative feedstocks. When grown in a mineral salt solution supplemented with 13.3% v/v swine
fecal material (SFM), cells exhibited pigmentation and suspended cell concentrations comparable to cultures grown in nutrient
broth. Glycine supplements stimulated production of cyanide in 13.3% v/v SFM. In contrast, glycine was inhibitory when added
at the time of inoculation in the more concentrated SFM, decreasing cell numbers and reducing ultimate bulk-solution cyanide
concentrations. However, aeration and addition of glycine to stationary phase cells grown on 13.3% v/v SFM anaerobically resulted
in rapid production and high concentrations (up to 38 mg l−1) of cyanide. This indicates that biogenesis of cyanide may be supported in remote areas using locally produced and inexpensive
agricultural feedstocks in place of commercial media. Journal of Industrial Microbiology & Biotechnology (2001) 26, 134–139.
Received 06 June 2000/ Accepted in revised form 30 September 2000 |
| |
Keywords: | : bioleaching gold Chromobacterium violaceum cyanogenesis |
本文献已被 SpringerLink 等数据库收录! |
|