Effect of the cyanide-producing bacterium Chromobacterium violaceum on ultraflat Au surfaces

Fairbrother, Lintern, Shapter, Joe, Brugger, Joel, Southam, Gordon, Pring, Allan and Reith, Frank (2009) Effect of the cyanide-producing bacterium Chromobacterium violaceum on ultraflat Au surfaces. Chemical Geology, 265 3-4: 313-320. doi:10.1016/j.chemgeo.2009.04.010


Author Fairbrother, Lintern
Shapter, Joe
Brugger, Joel
Southam, Gordon
Pring, Allan
Reith, Frank
Title Effect of the cyanide-producing bacterium Chromobacterium violaceum on ultraflat Au surfaces
Journal name Chemical Geology   Check publisher's open access policy
ISSN 0009-2541
1872-6836
Publication date 2009-07
Year available 2009
Sub-type Article (original research)
DOI 10.1016/j.chemgeo.2009.04.010
Open Access Status
Volume 265
Issue 3-4
Start page 313
End page 320
Total pages 8
Place of publication Amsterdam, The Netherlands
Publisher Elsevier BV
Collection year 2009
Language eng
Formatted abstract
 Solubilization, transport and re-precipitation of Au in the supergene environment can lead to the formation of secondary Au enrichment zones, revealed as geochemical anomalies and secondary gold grains. Cyanide-producing microorganisms can contribute to the solubilization of Au, and the cyanide produced may play an important role in the formation of ‘bacterioform’ structures observed on gold grains. To examine the effect of bacterial cyanide production on Au surfaces, ultra-flat Au foil was incubated in peptone meat extract (PME) medium in the presence of the cyanide-producing bacterium Chromobacterium violaceum for up to 56 days. Within seven days C. violaceum had formed biofilms on the Au surfaces, and cyanide produced by the bacteria had a measurable effect on the Au surface compared to abiotic controls. After removal of the biofilm by sonication in de-ionized water, the surfaces incubated with C. violaceum were significantly rougher compared to the negative controls. This was demonstrated by root mean square roughness (RMS) analyses and statistical t-testing following scanning tunneling microscopy (STM). Analyses of Au and cyanide in the growth medium supported the STM results: After 56 days of incubation 125 parts-per-billion (ppb) of Au was detected in solution or associated with C. violaceum cells. In contrast, Au solubilization and cyanide formation was not observed in negative controls. These experiments provide evidence that bacteria produce metabolites capable of mediating Au solubilization that may lead to the dispersion of Au in the environment, and suggest that dissolution of Au may contribute to the formation of ‘bacterioform’ structures commonly observed on secondary gold grains.
Keyword Gold
Bacteria
Chromobacterium violaceum
Bacterioform gold
Biofilm
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Earth Sciences Publications
 
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