Acidophile Diversity in Mineral Sulfide Oxidation

Norris, Paul R.

doi:10.1007/978-3-540-34911-2_10

Cited by 50 publications

(41 citation statements)

References 58 publications

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“…The inoculation of pure microbial strains or consortia has been proposed [23][24][25], but up to now this has not been a common practice. During heap operation, a great diversity of microbes are present, mostly bacteria and archaea [26][27][28]. The most well-known and first identified bioleaching bacteria are Acidithiobacillus ferrooxidans, Leptospirillum ferrooxidans, and Acidithiobacillus thiooxidans.…”

Section: Operating Factors Affecting the Bioleaching Processmentioning

confidence: 99%

Copper Bioleaching in Chile

Gentina

Acevedo

2016

Minerals

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Chile has a great tradition of producing and exporting copper. Over the last several decades, it has become the first producer on an international level. Its copper reserves are also the most important on the planet. However, after years of mineral exploitation, the ease of extracting copper oxides and ore copper content has diminished. To keep the production level high, the introduction of new technologies has become necessary. One that has been successful is bioleaching. Chile had the first commercial operation in the world exclusively via bioleaching copper sulfides. Nowadays, all bioleaching operations run in the country contribute to an estimated 10% of total copper production. This article presents antecedents that have contributed to the development of copper bioleaching in Chile.

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Section: Operating Factors Affecting the Bioleaching Processmentioning

confidence: 99%

Copper Bioleaching in Chile

Gentina

Acevedo

2016

Minerals

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“…Bioleaching of low-grade metal sulfides is often carried out in carefully constructed heaps of crushed or run-of-mine ore (reviewed by Olson et al [9]). Bioheaps of a multimetal ore from Talvivaara, Finland, showed that bioleaching continues during winter although ambient temperatures reach Ϫ30°C, limiting the growth of mesophilic, acidophilic microorganisms in exposed areas of the bioheaps (10). The temperature in the interior of the heap rises as high as 80°C due to exothermic oxidation reactions (11,12).…”

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confidence: 99%

Gene Identification and Substrate Regulation Provide Insights into Sulfur Accumulation during Bioleaching with the Psychrotolerant Acidophile Acidithiobacillus ferrivorans

Liljeqvist

Rzhepishevska

Dopson

2013

Appl Environ Microbiol

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The psychrotolerant acidophile Acidithiobacillus ferrivorans has been identified from cold environments and has been shown to use ferrous iron and inorganic sulfur compounds as its energy sources. A bioinformatic evaluation presented in this study suggested that Acidithiobacillus ferrivorans utilized a ferrous iron oxidation pathway similar to that of the related species Acidithiobacillus ferrooxidans. However, the inorganic sulfur oxidation pathway was less clear, since the Acidithiobacillus ferrivorans genome contained genes from both Acidithiobacillus ferrooxidans and Acidithiobacillus caldus encoding enzymes whose assigned functions are redundant. Transcriptional analysis revealed that the petA1 and petB1 genes (implicated in ferrous iron oxidation) were downregulated upon growth on the inorganic sulfur compound tetrathionate but were on average 10.5-fold upregulated in the presence of ferrous iron. In contrast, expression of cyoB1 (involved in inorganic sulfur compound oxidation) was decreased 6.6-fold upon growth on ferrous iron alone. Competition assays between ferrous iron and tetrathionate with Acidithiobacillus ferrivorans SS3 precultured on chalcopyrite mineral showed a preference for ferrous iron oxidation over tetrathionate oxidation. Also, pure and mixed cultures of psychrotolerant acidophiles were utilized for the bioleaching of metal sulfide minerals in stirred tank reactors at 5 and 25°C in order to investigate the fate of ferrous iron and inorganic sulfur compounds. Solid sulfur accumulated in bioleaching cultures growing on a chalcopyrite concentrate. Sulfur accumulation halted mineral solubilization, but sulfur was oxidized after metal release had ceased. The data indicated that ferrous iron was preferentially oxidized during growth on chalcopyrite, a finding with important implications for biomining in cold environments.

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“…Acidophilic Leptospirillum bacteria dominate this AMD system (15), other AMD systems (54), and bioleaching systems used for recovery of metals (19,53,86). These bacteria play pivotal roles in sulfide mineral dissolution because they are iron oxidizers (53,75), and ferric iron drives sulfide oxidation, leading to formation of metal-rich sulfuric acid solutions. According to a recent microscopy-based study (83), Leptospirillum group II are the first colonists in AMD biofilm communities whereas Leptospirillum group III generally appear later, sometimes partitioned within biofilm interiors.…”

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confidence: 99%

Community Genomic and Proteomic Analyses of Chemoautotrophic Iron-Oxidizing “ Leptospirillum rubarum ” (Group II) and “ Leptospirillum ferrodiazotrophum ” (Group III) Bacteria in Acid Mine Drainage Biofilms

Goltsman

Denef

Singer

et al. 2009

Appl Environ Microbiol

167

155

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We analyzed near-complete population (composite) genomic sequences for coexisting acidophilic ironoxidizing Leptospirillum group II and III bacteria (phylum Nitrospirae) and an extrachromosomal plasmid from a Richmond Mine, Iron Mountain, CA, acid mine drainage biofilm. Community proteomic analysis of the genomically characterized sample and two other biofilms identified 64.6% and 44.9% of the predicted proteins of Leptospirillum groups II and III, respectively, and 20% of the predicted plasmid proteins. The bacteria share 92% 16S rRNA gene sequence identity and >60% of their genes, including integrated plasmid-like regions. The extrachromosomal plasmid carries conjugation genes with detectable sequence similarity to genes in the integrated conjugative plasmid, but only those on the extrachromosomal element were identified by proteomics. Both bacterial groups have genes for community-essential functions, including carbon fixation and biosynthesis of vitamins, fatty acids, and biopolymers (including cellulose); proteomic analyses reveal these activities. Both Leptospirillum types have multiple pathways for osmotic protection. Although both are motile, signal transduction and methyl-accepting chemotaxis proteins are more abundant in Leptospirillum group III, consistent with its distribution in gradients within biofilms. Interestingly, Leptospirillum group II uses a methyldependent and Leptospirillum group III a methyl-independent response pathway. Although only Leptospirillum group III can fix nitrogen, these proteins were not identified by proteomics. The abundances of core proteins are similar in all communities, but the abundance levels of unique and shared proteins of unknown function vary. Some proteins unique to one organism were highly expressed and may be key to the functional and ecological differentiation of Leptospirillum groups II and III.To understand how microorganisms contribute to biogeochemical cycling, it is necessary to determine the roles of uncultivated as well as cultivated groups and to establish how these roles vary during ecological succession and when environmental conditions change. Shotgun genomic sequencing (metagenomics) has opened new opportunities for cultureindependent studies of microbial communities. Examples include investigations of acid mine drainage (AMD) biofilm communities (4, 43, 75), symbiosis in a marine worm involving sulfur-oxidizing and sulfate-reducing bacteria (85), and enhanced biological phosphorous removal by sludge communities (32). From these genomic data sets, it has been possible to reconstruct aspects of the metabolism of individual organisms (32) and coexisting community members (29, 75) and to identify which organisms contribute community-essential functions (75). An interesting question relates to how differences in metabolic potential between organisms from the same lineage allow them to occupy distinct niches. Identification of potentially adaptive traits in closely related organisms is also important from an evolutionary perspective.Genomic data do not...

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Acidophile Diversity in Mineral Sulfide Oxidation

Cited by 50 publications

References 58 publications

Copper Bioleaching in Chile

Copper Bioleaching in Chile

Gene Identification and Substrate Regulation Provide Insights into Sulfur Accumulation during Bioleaching with the Psychrotolerant Acidophile Acidithiobacillus ferrivorans

Community Genomic and Proteomic Analyses of Chemoautotrophic Iron-Oxidizing “ Leptospirillum rubarum ” (Group II) and “ Leptospirillum ferrodiazotrophum ” (Group III) Bacteria in Acid Mine Drainage Biofilms

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