Production of rhodanese by bacteria present in bio-oxidation plants used to recover gold from arsenopyrite concentrates

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dc.contributor.authorGardner M.N.
dc.contributor.authorRawlings D.E.
dc.date.accessioned2011-05-15T15:59:25Z
dc.date.available2011-05-15T15:59:25Z
dc.date.issued2000
dc.description.abstractConsiderably larger quantities of cyanide are required to solubilize gold following the bio-oxidation of gold-bearing ores compared with oxidation by physical-chemical processes. A possible cause of this excessive cyanide consumption is the presence of the enzyme rhodanese. Rhodanese activities were determined for the bacteria most commonly encountered in bio-oxidation tanks. Activities of between 6.4 and 8.2 μmol SCN- min-1 mg protein -1 were obtained for crude enzyme extracts of Thiobacillus ferrooxidans, Thiobacillus thiooxidans and Thiobacillus caldus, but no rhodanese activity was detected in Leptospirillum ferrooxidans. Rhodanese activities 2-2.5-fold higher were found in the total mixed cell mass from a bio-oxidation plant. T. ferrooxidans synthesized rhodanese irrespective of whether it was grown on iron or sulphur. With a PCR-based detection technique, only L. ferrooxidans and T. caldus cells were detected in the bio-oxidation tanks. As no rhodanese activity was associated with L. ferrooxidans, it was concluded that T. caldus was responsible for all of the rhodanese activity. Production of rhodanese by T. caldus in batch culture was growth phase-dependent and highest during early stationary phase. Although the sulphur-oxidizing bacteria were clearly able to convert cyanide to thiocyanate, it is unlikely that this rhodanese activity is responsible for the excessive cyanide wastage at the high pH values associated with the gold solubilization process.
dc.description.versionArticle
dc.identifier.citationJournal of Applied Microbiology
dc.identifier.citation89
dc.identifier.citation1
dc.identifier.issn13645072
dc.identifier.other10.1046/j.1365-2672.2000.01117.x
dc.identifier.urihttp://hdl.handle.net/10019.1/11166
dc.subjectgold
dc.subjectthiosulfate sulfurtransferase
dc.subjectAcidithiobacillus ferrooxidans
dc.subjectAcidithiobacillus thiooxidans
dc.subjectarticle
dc.subjectcatalysis
dc.subjectdecomposition
dc.subjectenzyme activity
dc.subjectoxidation
dc.subjectpH
dc.subjectsolubilization
dc.subjectsynthesis
dc.subjectwater flow
dc.subjectArsenicals
dc.subjectBacteria
dc.subjectCyanides
dc.subjectGold
dc.subjectHydrogen-Ion Concentration
dc.subjectIndustrial Microbiology
dc.subjectIron Compounds
dc.subjectOxidation-Reduction
dc.subjectPolymerase Chain Reaction
dc.subjectSulfides
dc.subjectThiobacillus
dc.subjectThiosulfate Sulfurtransferase
dc.titleProduction of rhodanese by bacteria present in bio-oxidation plants used to recover gold from arsenopyrite concentrates
dc.typeArticle
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