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

Fairbrother, Lintern; Shapter, Joseph G.; Brugger, Joël; Southam, Gordon; Pring, Allan; Reith, Frank

doi:10.1016/j.gexplo.2008.12.011

Cited by 3 publications

(3 citation statements)

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“…Previous experimental studies have shown that bacterial biofi lms increase Au mobility Fairbrother et al, 2009). Biofi lms have been observed on Au pellets incubated in auriferous soils, where their presence led to a doubling of Au solubilization compared to unamended controls, yet mobilization and dispersion mechanisms remained unexplained Fairbrother et al, 2009). Cyano-, sulfi de-oxidizing and sulfate-reducing, and metallophilic bacteria have been shown to biomineralize nanoparticulate Au from aqueous Au(I/III) complexes Southam, 2005, 2007;Lengke et al, 2006aLengke et al, , 2006b.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Nanoparticle factories: Biofilms hold the key to gold dispersion and nugget formation

Reith

Fairbrother

Nolze

et al. 2010

Geology

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142

109

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Biofi lms living on gold (Au) grains play a key role in the biogeochemical cycle of Au by promoting the dispersion of Au via the formation of Au nanoparticles as well as the formation of secondary biomorphic Au. Gold grains from Queensland, Australia, are covered by a polymorphic, organic-inorganic layer that is up to 40 µm thick. It consists of a bacterial biofi lm containing Au nanoparticles associated with extracellular polymeric substances as well as bacterioform Au. Focused ion beam (FIB) sectioning through the biofi lm revealed that aggregates of nanoparticulate Au line open spaces beneath the active biofi lm layer. These aggregates (bacterioform Au type 1) resulted from the reprecipitation of dissolved Au, and their internal growth structures provide direct evidence for coarsening of the Au grains. At the contact between the polymorphic layer and the primary Au, bacterioform Au type 2 is present. It consists of solid rounded forms into which crystal boundaries of underlying primary Au extend, and is the result of dealloying and Ag dissolution from the primary Au. This study demonstrates that (1) microbially driven dissolution, precipitation, and aggregation lead to the formation of bacterioform Au and contribute to the growth of Au grains under supergene conditions, and (2) the microbially driven mobilization of coarse Au into nanoparticles plays a key role in mediating the mobility of Au in surface environments, because the release of nanoparticulate Au upon biofi lm disintegration greatly enhances environmental mobility compared to Au complexes only.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Nanoparticle factories: Biofilms hold the key to gold dispersion and nugget formation

Reith

Fairbrother

Nolze

et al. 2010

Geology

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142

109

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“…cystine a precursor for thiosulphate and glycine has been shown to be converted to cyanide by a number of bacteria, such as Chromobacterium violaceum and a number Pseudomonas spp. (Kunert and Stransky, 1988;Faramarzi et al, 2004;Faramarzi and Brandl, 2006;Fairbrother et al, 2009). In a number of studies, these organisms have been shown to solubilise gold from a range of materials such as gold containing ore and electronics waste (Faramarzi et al, 2004;Faramarzi and Brandl, 2006;Fairbrother et al, 2009).…”

Section: Bio-oxidation Of Sulphides -An Established Biohydrometallurgmentioning

confidence: 99%

Potential utilisation of micro-organisms in gold processing: a review

Reith¹,

Zammit²,

Rogers³

et al. 2012

Mineral Processing and Extractive Metallurgy

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Using iron and sulphur oxidising bacteria to catalyse the breakdown of sulphides that host the gold is an important biological method for the pretreatment of refractory gold ores. Following this biological treatment, a combination of chemical and physical methods is used for leaching (such as the cyanide process) and concentration (such as carbon in pulp or electrowinning) of the gold. Although these methods are well accepted by industry, they harbour limitations in the processing of low grade refractory ores and regulatory agency/public acceptance of cyanide use. Thus, it is beneficial for industry to develop environmentally friendly, as well as cost efficient, leaching and concentration techniques that are based on micro-organisms. This may soon be possible by adapting the results of recent multidisciplinary research, which has shown that micro-organisms are capable of driving a biogeochemical cycle of gold dispersion, transport and re-concentration in the supergene environment. The indigenous microbiota in biologically active soil microcosms from a number of Australian sites are capable of solubilising up to 80 wt-% of the gold contained in soils and deeper regolith materials. Studies using molecular microbial techniques have shown that a metallophilic bacterium, Cupriavidus metallidurans, is present in biofilms on gold grains from a number of Australian sites. Cupriavidus metallidurans is capable of actively accumulating gold from solution and therefore contributes to the formation of secondary gold grains and nuggets. Identifying the biochemical and physiological pathways that lead to the dispersion and accumulation of gold in regolith and quantifying the reaction kinetics of these processes may thus lead to the development of industrial bio-processing capacities for gold containing ores.

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Bacillus cereus, a geobiological marker for gold prospecting isolated from soil from the Jiaodong Gold Mine

Lao

Shen²,

Zhu³

et al. 2020

Journal of Geochemical Exploration

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

Cited by 3 publications

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Nanoparticle factories: Biofilms hold the key to gold dispersion and nugget formation

Nanoparticle factories: Biofilms hold the key to gold dispersion and nugget formation

Potential utilisation of micro-organisms in gold processing: a review

Bacillus cereus, a geobiological marker for gold prospecting isolated from soil from the Jiaodong Gold Mine

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