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Hetz SA, Schippers A. Do ferrous iron-oxidizing acidophiles ( Leptospirillum spp.) disturb aerobic bioleaching of laterite ores by sulfur-oxidizing acidophiles ( Acidithiobacillus spp.)? Front Microbiol 2024; 15:1359019. [PMID: 38655078 PMCID: PMC11035876 DOI: 10.3389/fmicb.2024.1359019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Accepted: 03/25/2024] [Indexed: 04/26/2024] Open
Abstract
The extraction of nickel, cobalt, and other metals from laterite ores via bioleaching with sulfur-oxidizing and ferric iron-reducing, autotrophic, acidophilic bacteria (e.g. Acidithiobacillus species) has been demonstrated under anaerobic as well as aerobic conditions in experiments in different laboratories. This study demonstrated the bioleaching of laterites from Brazil with the addition of elemental sulfur in 2-L stirred-tank bioreactors with pure and mixed cultures of Acidithiobacillus and Sulfobacillus species under aerobic conditions. In particular, a potential disturbance of mineral dissolution under aerobic conditions by ferrous iron-oxidizing acidophiles likely introduced as contaminants in an applied bioleaching process was investigated with Leptospirillum ferrooxidans at 30°C and Leptospirillum ferriphilum at 40°C, at maintained pH 1.5 or without maintained pH leading to an increase in acidity (with pH values <1.0) due to the biological production of sulfuric acid. Despite the proportion of ferrous iron to the total amount of extracted iron in the solution being drastically reduced in the presence of Leptospirillum species, there was a negligible effect on the extraction efficiency of nickel and cobalt, which is positive news for laterite bioleaching under aerobic conditions.
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Affiliation(s)
- Stefanie A. Hetz
- Federal Institute for Geosciences and Natural Resources (BGR), Hannover, Germany
| | - Axel Schippers
- Federal Institute for Geosciences and Natural Resources (BGR), Hannover, Germany
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2
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Myriam P, Braulio P, Javiera RA, Claudia MV, Omar O, Renato C, Gloria L. Insights into Systems for Iron-Sulfur Cluster Biosynthesis in Acidophilic Microorganisms. J Microbiol Biotechnol 2022; 32:1110-1119. [PMID: 36039043 PMCID: PMC9628965 DOI: 10.4014/jmb.2206.06045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 08/02/2022] [Accepted: 08/17/2022] [Indexed: 12/15/2022]
Abstract
Fe-S clusters are versatile and essential cofactors that participate in multiple and fundamental biological processes. In Escherichia coli, the biogenesis of these cofactors requires either the housekeeping Isc pathway, or the stress-induced Suf pathway which plays a general role under conditions of oxidative stress or iron limitation. In the present work, the Fe-S cluster assembly Isc and Suf systems of acidophilic Bacteria and Archaea, which thrive in highly oxidative environments, were studied. This analysis revealed that acidophilic microorganisms have a complete set of genes encoding for a single system (either Suf or Isc). In acidophilic Proteobacteria and Nitrospirae, a complete set of isc genes (iscRSUAX-hscBA-fdx), but not genes coding for the Suf system, was detected. The activity of the Isc system was studied in Leptospirillum sp. CF-1 (Nitrospirae). RT-PCR experiments showed that eight candidate genes were co-transcribed and conform the isc operon in this strain. Additionally, RT-qPCR assays showed that the expression of the iscS gene was significantly up-regulated in cells exposed to oxidative stress imposed by 260 mM Fe2(SO4)3 for 1 h or iron starvation for 3 h. The activity of cysteine desulfurase (IscS) in CF-1 cell extracts was also up-regulated under such conditions. Thus, the Isc system from Leptospirillum sp. CF-1 seems to play an active role in stressful environments. These results contribute to a better understanding of the distribution and role of Fe-S cluster protein biogenesis systems in organisms that thrive in extreme environmental conditions.
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Affiliation(s)
- Pérez Myriam
- Universidad de Santiago de Chile (USACH), Facultad de Química y Biología, Departamento de Biología. Av. Libertador Bernardo O´Higgins 3363, Estación Central, Santiago 9170022, Chile
| | - Paillavil Braulio
- Universidad de Santiago de Chile (USACH), Facultad de Química y Biología, Departamento de Biología. Av. Libertador Bernardo O´Higgins 3363, Estación Central, Santiago 9170022, Chile
| | - Rivera-Araya Javiera
- Universidad de Santiago de Chile (USACH), Facultad de Química y Biología, Departamento de Biología. Av. Libertador Bernardo O´Higgins 3363, Estación Central, Santiago 9170022, Chile
| | - Muñoz-Villagrán Claudia
- Universidad de Santiago de Chile (USACH), Facultad de Química y Biología, Departamento de Biología. Av. Libertador Bernardo O´Higgins 3363, Estación Central, Santiago 9170022, Chile
| | - Orellana Omar
- Universidad de Chile, Facultad de Medicina, Instituto de Ciencias Biomédicas, Laboratorio de Biología Molecular Bacteriana City, 8380453, Chile
| | - Chávez Renato
- Universidad de Santiago de Chile (USACH), Facultad de Química y Biología, Departamento de Biología. Av. Libertador Bernardo O´Higgins 3363, Estación Central, Santiago 9170022, Chile
| | - Levicán Gloria
- Universidad de Santiago de Chile (USACH), Facultad de Química y Biología, Departamento de Biología. Av. Libertador Bernardo O´Higgins 3363, Estación Central, Santiago 9170022, Chile,Corresponding author Phone: +56-2-27181125 E-mail:
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3
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Javier RA, Matías R, Alonso F, Renato C, Gloria L. A novel gene from the acidophilic bacterium Leptospirillum sp. CF-1 and its role in oxidative stress and chromate tolerance. Biol Res 2022; 55:19. [PMID: 35525996 PMCID: PMC9080137 DOI: 10.1186/s40659-022-00388-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 04/15/2022] [Indexed: 11/16/2022] Open
Abstract
Background Acidophilic microorganisms like Leptospirillum sp. CF-1 thrive in environments with extremely low pH and high concentrations of dissolved heavy metals that can induce the generation of reactive oxygen species (ROS). Several hypothetical genes and proteins from Leptospirillum sp. CF-1 are known to be up-regulated under oxidative stress conditions. Results In the present work, the function of hypothetical gene ABH19_09590 from Leptospirillum sp. CF-1 was studied. Heterologous expression of this gene in Escherichia coli led to an increase in the ability to grow under oxidant conditions with 5 mM K2CrO4 or 5 mM H2O2. Similarly, a significant reduction in ROS production in E. coli transformed with a plasmid carrying ABH19_09590 was observed after exposure to these oxidative stress elicitors for 30 min, compared to a strain complemented with the empty vector. A co-transcriptional study using RT-PCR showed that ABH19_09590 is contained in an operon, here named the “och” operon, that also contains ABH19_09585, ABH19_09595 and ABH19_09600 genes. The expression of the och operon was significantly up-regulated in Leptospirillum sp. CF-1 exposed to 5 mM K2CrO4 for 15 and 30 min. Genes of this operon potentially encode a NADH:ubiquinone oxidoreductase, a CXXC motif-containing protein likely involved in thiol/disulfide exchange, a hypothetical protein, and a di-hydroxy-acid dehydratase. A comparative genomic analysis revealed that the och operon is a characteristic genetic determinant of the Leptospirillum genus that is not present in other acidophiles. Conclusions Altogether, these results suggest that the och operon plays a protective role against chromate and hydrogen peroxide and is an important mechanism required to face polyextremophilic conditions in acid environments.
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Affiliation(s)
- Rivera-Araya Javier
- Biology Department, Faculty of Chemistry and Biology, University of Santiago of Chile (USACH), Santiago, Chile
| | - Riveros Matías
- Biology Department, Faculty of Chemistry and Biology, University of Santiago of Chile (USACH), Santiago, Chile
| | - Ferrer Alonso
- Núcleo de Química y Bioquímica, Facultad de Ciencias, Universidad Mayor, Santiago, Chile
| | - Chávez Renato
- Biology Department, Faculty of Chemistry and Biology, University of Santiago of Chile (USACH), Santiago, Chile
| | - Levicán Gloria
- Biology Department, Faculty of Chemistry and Biology, University of Santiago of Chile (USACH), Santiago, Chile.
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4
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Blake RC, Shively JE, Timkovich R, White RA. Homogeneous Cytochrome 579 Is an Octamer That Reacts Too Slowly With Soluble Iron to Be the Initial Iron Oxidase in the Respiratory Chain of Leptospirillum ferriphilum. Front Microbiol 2021; 12:673066. [PMID: 34012429 PMCID: PMC8126622 DOI: 10.3389/fmicb.2021.673066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 04/13/2021] [Indexed: 11/20/2022] Open
Abstract
The exact role that cytochrome 579 plays in the aerobic iron respiratory chain of Leptospirillum ferriphilum is unclear. This paper presents genomic, structural, and kinetic data on the cytochrome 579 purified from cell-free extracts of L. ferriphilum cultured on soluble iron. Electrospray mass spectrometry of electrophoretically homogeneous cytochrome 579 yielded two principal peaks at 16,015 and 16,141 Daltons. N-terminal amino acid sequencing of the purified protein yielded data that were used to determine the following: there are seven homologs of cytochrome 579; each homolog possesses the CXXCH heme-binding motif found in c-type cytochromes; each of the seven sequenced strains of L. ferriphilum expresses only two of the seven homologs of the cytochrome; and each homolog contains an N-terminal signal peptide that directs the mature protein to an extra-cytoplasmic location. Static light scattering and macroion mobility measurements on native cytochrome 579 yielded masses of 125 and 135 kDaltons, respectively. The reduced alkaline pyridine hemochromogen spectrum of the purified cytochrome had an alpha absorbance maximum at 567 nm, a property not exhibited by any known heme group. The iron-dependent reduction and oxidation of the octameric cytochrome exhibited positively cooperative kinetic behavior with apparent Hill coefficients of 5.0 and 3.7, respectively, when the purified protein was mixed with mM concentrations of soluble iron. Consequently, the extrapolated rates of reduction at sub-mM iron concentrations were far too slow for cytochrome 579 to be the initial iron oxidase in the aerobic respiratory chain of L. ferriphilum. Rather, these observations support the hypothesis that the acid-stable cytochrome 579 is a periplasmic conduit of electrons from initial iron oxidation in the outer membrane of this Gram-negative bacterium to a terminal oxidase in the plasma membrane.
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Affiliation(s)
- Robert C Blake
- Division of Basic Pharmaceutical Sciences, Xavier University of Louisiana, New Orleans, LA, United States
| | - John E Shively
- Division of Immunology, Beckman Research Institute of the City of Hope, Duarte, CA, United States
| | - Russell Timkovich
- Department of Chemistry, University of Alabama, Tuscaloosa, AL, United States
| | - Richard Allen White
- Department of Bioinformatics and Genomics, University of North Carolina, Charlotte, NC, United States.,Department of Bioinformatics and Genomics, University of North Carolina, Kannapolis, NC, United States.,Australian Centre for Astrobiology, University of New South Wales, Sydney, NSW, Australia
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5
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Rojas-Gätjens D, Arce-Rodríguez A, Puente-Sánchez F, Avendaño R, Libby E, Mora-Amador R, Rojas-Jimenez K, Fuentes-Schweizer P, Pieper DH, Chavarría M. Temperature and elemental sulfur shape microbial communities in two extremely acidic aquatic volcanic environments. Extremophiles 2021; 25:85-99. [PMID: 33416983 DOI: 10.1007/s00792-020-01213-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 12/16/2020] [Indexed: 01/22/2023]
Abstract
Aquatic environments of volcanic origin provide an exceptional opportunity to study the adaptations of microorganisms to early planet life conditions. Here, we characterized the prokaryotic communities and physicochemical properties of seepage sites at the bottom of the Poas Volcano crater and the Agrio River, two geologically related extremely acidic environments located in Costa Rica. Both locations hold a low pH (1.79-2.20) and have high sulfate and iron concentrations (Fe = 47-206 mg/L, SO42- = 1170-2460 mg/L), but significant differences in their temperature (90.0-95.0 ºC in the seepages at Poas Volcano, 19.1-26.6 ºC in Agrio River) and in the elemental sulfur content. Based on the analysis of 16S rRNA gene sequences, we determined that Sulfobacillus spp. represented more than half of the sequences in Poas Volcano seepage sites, while Agrio River was dominated by Leptospirillum and members of the archaeal order Thermoplasmatales. Both environments share some chemical characteristics and part of their microbiota, however, the temperature and the reduced sulfur are likely the main distinguishing features, ultimately shaping their microbial communities. Our data suggest that in the Poas Volcano-Agrio River system there is a common metabolism but with specialization of species that adapt to the physicochemical conditions of each environment.
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Affiliation(s)
- Diego Rojas-Gätjens
- Centro Nacional de Innovaciones Biotecnológicas (CENIBiot), CeNAT-CONARE, San José, 1174-1200, Costa Rica
| | - Alejandro Arce-Rodríguez
- Microbial Interactions and Processes Research Group, Helmholtz Centre for Infection Research, 38124, Braunschweig, Germany.,Department of Molecular Bacteriology, Helmholtz Centre for Infection Research, 38124, Braunschweig, Germany
| | - Fernando Puente-Sánchez
- Systems Biology Program, Centro Nacional de Biotecnología (CNB-CSIC), C/Darwin 3, 28049, Madrid, Spain
| | - Roberto Avendaño
- Centro Nacional de Innovaciones Biotecnológicas (CENIBiot), CeNAT-CONARE, San José, 1174-1200, Costa Rica
| | - Eduardo Libby
- Escuela de Química, Universidad de Costa Rica, San Pedro de Montes de Oca, San José, 11501-2060, Costa Rica
| | - Raúl Mora-Amador
- Escuela Centroamericana de Geología, Universidad de Costa Rica, San José, 11501-2060, Costa Rica.,Laboratorio de Ecología Urbana, Universidad Estatal a Distancia, San José, 11501-2060, Costa Rica
| | - Keilor Rojas-Jimenez
- Escuela de Biología, Universidad de Costa Rica, San José, 11501-2060, Costa Rica
| | - Paola Fuentes-Schweizer
- Escuela de Química, Universidad de Costa Rica, San Pedro de Montes de Oca, San José, 11501-2060, Costa Rica.,Centro de Investigación en Electroquímica y Energía Química (CELEQ), Universidad de Costa Rica, San José, 11501-2060, Costa Rica
| | - Dietmar H Pieper
- Microbial Interactions and Processes Research Group, Helmholtz Centre for Infection Research, 38124, Braunschweig, Germany
| | - Max Chavarría
- Centro Nacional de Innovaciones Biotecnológicas (CENIBiot), CeNAT-CONARE, San José, 1174-1200, Costa Rica. .,Escuela de Química, Universidad de Costa Rica, San Pedro de Montes de Oca, San José, 11501-2060, Costa Rica. .,Centro de Investigaciones en Productos Naturales (CIPRONA), Universidad de Costa Rica, San José, 11501-2060, Costa Rica.
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6
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Christel S, Herold M, Bellenberg S, Buetti-Dinh A, El Hajjami M, Pivkin IV, Sand W, Wilmes P, Poetsch A, Vera M, Dopson M. Weak Iron Oxidation by Sulfobacillus thermosulfidooxidans Maintains a Favorable Redox Potential for Chalcopyrite Bioleaching. Front Microbiol 2018; 9:3059. [PMID: 30631311 PMCID: PMC6315122 DOI: 10.3389/fmicb.2018.03059] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Accepted: 11/27/2018] [Indexed: 11/13/2022] Open
Abstract
Bioleaching is an emerging technology, describing the microbially assisted dissolution of sulfidic ores that provides a more environmentally friendly alternative to many traditional metal extraction methods, such as roasting or smelting. Industrial interest is steadily increasing and today, circa 15-20% of the world's copper production can be traced back to this method. However, bioleaching of the world's most abundant copper mineral chalcopyrite suffers from low dissolution rates, often attributed to passivating layers, which need to be overcome to use this technology to its full potential. To prevent these passivating layers from forming, leaching needs to occur at a low oxidation/reduction potential (ORP), but chemical redox control in bioleaching heaps is difficult and costly. As an alternative, selected weak iron-oxidizers could be employed that are incapable of scavenging exceedingly low concentrations of iron and therefore, raise the ORP just above the onset of bioleaching, but not high enough to allow for the occurrence of passivation. In this study, we report that microbial iron oxidation by Sulfobacillus thermosulfidooxidans meets these specifications. Chalcopyrite concentrate bioleaching experiments with S. thermosulfidooxidans as the sole iron oxidizer exhibited significantly lower redox potentials and higher release of copper compared to communities containing the strong iron oxidizer Leptospirillum ferriphilum. Transcriptomic response to single and co-culture of these two iron oxidizers was studied and revealed a greatly decreased number of mRNA transcripts ascribed to iron oxidation in S. thermosulfidooxidans when cultured in the presence of L. ferriphilum. This allowed for the identification of genes potentially responsible for S. thermosulfidooxidans' weaker iron oxidation to be studied in the future, as well as underlined the need for new mechanisms to control the microbial population in bioleaching heaps.
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Affiliation(s)
- Stephan Christel
- Centre for Ecology and Evolution in Microbial Model Systems, Linnaeus University, Kalmar, Sweden
| | - Malte Herold
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Belvaux, Luxembourg
| | - Sören Bellenberg
- Centre for Ecology and Evolution in Microbial Model Systems, Linnaeus University, Kalmar, Sweden.,Aquatic Biotechnology, Universität Duisburg-Essen, Essen, Germany
| | - Antoine Buetti-Dinh
- Faculty of Informatics, Institute of Computational Science, Università della Svizzera Italiana, Lugano, Switzerland.,Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | | | - Igor V Pivkin
- Faculty of Informatics, Institute of Computational Science, Università della Svizzera Italiana, Lugano, Switzerland.,Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Wolfgang Sand
- Aquatic Biotechnology, Universität Duisburg-Essen, Essen, Germany.,College of Environmental Science and Engineering, Donghua University, Shanghai, China.,Mining Academy and Technical University Freiberg, Freiberg, Germany
| | - Paul Wilmes
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Belvaux, Luxembourg
| | - Ansgar Poetsch
- Plant Biochemistry, Ruhr-Universität Bochum, Bochum, Germany.,School of Biomedical and Healthcare Sciences, Plymouth University, Plymouth, United Kingdom
| | - Mario Vera
- Schools of Engineering, Medicine and Biological Sciences, Institute for Biological and Medical Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile.,Department of Hydraulic and Environmental Engineering, School of Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Mark Dopson
- Centre for Ecology and Evolution in Microbial Model Systems, Linnaeus University, Kalmar, Sweden
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7
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Christel S, Herold M, Bellenberg S, El Hajjami M, Buetti-Dinh A, Pivkin IV, Sand W, Wilmes P, Poetsch A, Dopson M. Multi-omics Reveals the Lifestyle of the Acidophilic, Mineral-Oxidizing Model Species Leptospirillum ferriphilum T. Appl Environ Microbiol 2018; 84:e02091-17. [PMID: 29150517 DOI: 10.1128/AEM.02091-17] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 11/09/2017] [Indexed: 11/20/2022] Open
Abstract
Leptospirillum ferriphilum plays a major role in acidic, metal-rich environments, where it represents one of the most prevalent iron oxidizers. These milieus include acid rock and mine drainage as well as biomining operations. Despite its perceived importance, no complete genome sequence of the type strain of this model species is available, limiting the possibilities to investigate the strategies and adaptations that Leptospirillum ferriphilum DSM 14647T (here referred to as Leptospirillum ferriphilum T) applies to survive and compete in its niche. This study presents a complete, circular genome of Leptospirillum ferriphilum T obtained by PacBio single-molecule real-time (SMRT) long-read sequencing for use as a high-quality reference. Analysis of the functionally annotated genome, mRNA transcripts, and protein concentrations revealed a previously undiscovered nitrogenase cluster for atmospheric nitrogen fixation and elucidated metabolic systems taking part in energy conservation, carbon fixation, pH homeostasis, heavy metal tolerance, the oxidative stress response, chemotaxis and motility, quorum sensing, and biofilm formation. Additionally, mRNA transcript counts and protein concentrations were compared between cells grown in continuous culture using ferrous iron as the substrate and those grown in bioleaching cultures containing chalcopyrite (CuFeS2). Adaptations of Leptospirillum ferriphilum T to growth on chalcopyrite included the possibly enhanced production of reducing power, reduced carbon dioxide fixation, as well as elevated levels of RNA transcripts and proteins involved in heavy metal resistance, with special emphasis on copper efflux systems. Finally, the expression and translation of genes responsible for chemotaxis and motility were enhanced.IMPORTANCE Leptospirillum ferriphilum is one of the most important iron oxidizers in the context of acidic and metal-rich environments during moderately thermophilic biomining. A high-quality circular genome of Leptospirillum ferriphilum T coupled with functional omics data provides new insights into its metabolic properties, such as the novel identification of genes for atmospheric nitrogen fixation, and represents an essential step for further accurate proteomic and transcriptomic investigation of this acidophile model species in the future. Additionally, light is shed on adaptation strategies of Leptospirillum ferriphilum T for growth on the copper mineral chalcopyrite. These data can be applied to deepen our understanding and optimization of bioleaching and biooxidation, techniques that present sustainable and environmentally friendly alternatives to many traditional methods for metal extraction.
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8
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Smith SL, Johnson DB. Growth of Leptospirillum ferriphilum in sulfur medium in co-culture with Acidithiobacillus caldus. Extremophiles 2018; 22:327-333. [PMID: 29330649 PMCID: PMC5847181 DOI: 10.1007/s00792-018-1001-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 12/23/2017] [Indexed: 11/28/2022]
Abstract
Leptospirillum ferriphilum and Acidithiobacillus caldus are both thermotolerant acidophilic bacteria that frequently co-exist in natural and man-made environments, such as biomining sites. Both are aerobic chemolithotrophs; L. ferriphilum is known only to use ferrous iron as electron donor, while A. caldus can use zero-valent and reduced sulfur, and also hydrogen, as electron donors. It has recently been demonstrated that A. caldus reduces ferric iron to ferrous when grown aerobically on sulfur. Experiments were carried out which demonstrated that this allowed L. ferriphilum to be sustained for protracted periods in media containing very little soluble iron, implying that dynamic cycling of iron occurred in aerobic mixed cultures of these two bacteria. In contrast, numbers of viable L. ferriphilum rapidly declined in mixed cultures that did not contain sulfur. Data also indicated that growth of A. caldus was partially inhibited in the presence of L. ferriphilum. This was shown to be due to greater sensitivity of the sulfur-oxidizer to ferric than to ferrous iron, and to highly positive redox potentials, which are characteristic of cultures containing Leptospirillum spp. The implications of these results in the microbial ecology of extremely acidic environments and in commercial bioprocessing applications are discussed.
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Affiliation(s)
- Sarah L Smith
- College of Natural Sciences, Bangor University, Deiniol Road, Bangor, LL57 2UW, UK.
| | - D Barrie Johnson
- College of Natural Sciences, Bangor University, Deiniol Road, Bangor, LL57 2UW, UK
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9
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Hedrich S, Guézennec AG, Charron M, Schippers A, Joulian C. Quantitative Monitoring of Microbial Species during Bioleaching of a Copper Concentrate. Front Microbiol 2017; 7:2044. [PMID: 28066365 PMCID: PMC5167697 DOI: 10.3389/fmicb.2016.02044] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 12/05/2016] [Indexed: 12/18/2022] Open
Abstract
Monitoring of the microbial community in bioleaching processes is essential in order to control process parameters and enhance the leaching efficiency. Suitable methods are, however, limited as they are usually not adapted to bioleaching samples and often no taxon-specific assays are available in the literature for these types of consortia. Therefore, our study focused on the development of novel quantitative real-time PCR (qPCR) assays for the quantification of Acidithiobacillus caldus, Leptospirillum ferriphilum, Sulfobacillus thermosulfidooxidans, and Sulfobacillus benefaciens and comparison of the results with data from other common molecular monitoring methods in order to evaluate their accuracy and specificity. Stirred tank bioreactors for the leaching of copper concentrate, housing a consortium of acidophilic, moderately thermophilic bacteria, relevant in several bioleaching operations, served as a model system. The microbial community analysis via qPCR allowed a precise monitoring of the evolution of total biomass as well as abundance of specific species. Data achieved by the standard fingerprinting methods, terminal restriction fragment length polymorphism (T-RFLP) and capillary electrophoresis single strand conformation polymorphism (CE-SSCP) on the same samples followed the same trend as qPCR data. The main added value of qPCR was, however, to provide quantitative data for each species whereas only relative abundance could be deduced from T-RFLP and CE-SSCP profiles. Additional value was obtained by applying two further quantitative methods which do not require nucleic acid extraction, total cell counting after SYBR Green staining and metal sulfide oxidation activity measurements via microcalorimetry. Overall, these complementary methods allow for an efficient quantitative microbial community monitoring in various bioleaching operations.
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Affiliation(s)
- Sabrina Hedrich
- Resource Geochemistry, Federal Institute for Geosciences and Natural Resources Hannover, Germany
| | | | - Mickaël Charron
- Bureau de Recherches Géologiques et Minières Orléans, France
| | - Axel Schippers
- Resource Geochemistry, Federal Institute for Geosciences and Natural Resources Hannover, Germany
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10
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Diaby N, Dold B, Rohrbach E, Holliger C, Rossi P. Temporal evolution of bacterial communities associated with the in situ wetland-based remediation of a marine shore porphyry copper tailings deposit. Sci Total Environ 2015; 533:110-121. [PMID: 26151655 DOI: 10.1016/j.scitotenv.2015.06.076] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 06/18/2015] [Accepted: 06/19/2015] [Indexed: 06/04/2023]
Abstract
Mine tailings are a serious threat to the environment and public health. Remediation of these residues can be carried out effectively by the activation of specific microbial processes. This article presents detailed information about temporal changes in bacterial community composition during the remediation of a section of porphyry copper tailings deposited on the Bahía de Ite shoreline (Peru). An experimental remediation cell was flooded and transformed into a wetland in order to prevent oxidation processes, immobilizing metals. Initially, the top oxidation zone of the tailings deposit displayed a low pH (3.1) and high concentrations of metals, sulfate, and chloride, in a sandy grain size geological matrix. This habitat was dominated by sulfur- and iron-oxidizing bacteria, such as Leptospirillum spp., Acidithiobacillus spp., and Sulfobacillus spp., in a microbial community which structure resembled acid mine drainage environments. After wetland implementation, the cell was water-saturated, the acidity was consumed and metals dropped to a fraction of their initial respective concentrations. Bacterial communities analyzed by massive sequencing showed time-dependent changes both in composition and cell numbers. The final remediation stage was characterized by the highest bacterial diversity and evenness. Aside from classical sulfate reducers from the phyla δ-Proteobacteria and Firmicutes, community structure comprised taxa derived from very diverse habitats. The community was also characterized by an elevated proportion of rare phyla and unaffiliated sequences. Numerical ecology analysis confirmed that the temporal population evolution was driven by pH, redox, and K. Results of this study demonstrated the usefulness of a detailed follow-up of the remediation process, not only for the elucidation of the communities gradually switching from autotrophic, oxidizing to heterotrophic and reducing living conditions, but also for the long term management of the remediation wetlands.
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Affiliation(s)
- N Diaby
- University of Lausanne, Institute of Mineralogy and Geochemistry, Anthropole, Lausanne, Switzerland
| | - B Dold
- University of Lausanne, Institute of Mineralogy and Geochemistry, Anthropole, Lausanne, Switzerland
| | - E Rohrbach
- Ecole Polytechnique Fédérale de Lausanne (EPFL), School of Architecture, Civil and Environmental Engineering, Laboratory for Environmental Biotechnology, Lausanne, Switzerland
| | - C Holliger
- Ecole Polytechnique Fédérale de Lausanne (EPFL), School of Architecture, Civil and Environmental Engineering, Laboratory for Environmental Biotechnology, Lausanne, Switzerland
| | - P Rossi
- Ecole Polytechnique Fédérale de Lausanne (EPFL), School of Architecture, Civil and Environmental Engineering, Central Environmental Laboratory, Lausanne, Switzerland.
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11
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Yan L, Zhang S, Yu G, Ni Y, Wang W, Hu H, Chen P. Draft genome of iron-oxidizing bacterium Leptospirillum sp. YQP-1 isolated from a volcanic lake in the Wudalianchi volcano, China. Genom Data 2015; 6:164-5. [PMID: 26697362 PMCID: PMC4664748 DOI: 10.1016/j.gdata.2015.09.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 08/29/2015] [Accepted: 09/02/2015] [Indexed: 11/19/2022]
Abstract
Leptospirillum sp. YQP-1, a member of iron-oxidizing bacteria was isolated from volcanic lake in northeast China. Here, we report the draft genome sequence of the strain YQP-1 with a total genome size of 3,103,789 bp from 85 scaffolds (104 contigs) with 58.64% G + C content. The genome sequence can be accessed at DDBJ/EMBL/GenBank under the accession no. LIEB00000000.
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Affiliation(s)
- Lei Yan
- College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Xinfeng Road No.5, Daqing 163319, PR China
- Corresponding author.
| | - Shuang Zhang
- College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Xinfeng Road No.5, Daqing 163319, PR China
| | - Gaobo Yu
- College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Xinfeng Road No.5, Daqing 163319, PR China
| | - Yongqing Ni
- School of Food Sciences, Shihezi University, North 4th Road No. 280, Shihezi 832003, PR China
| | - Weidong Wang
- College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Xinfeng Road No.5, Daqing 163319, PR China
| | - Huixin Hu
- College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Xinfeng Road No.5, Daqing 163319, PR China
| | - Peng Chen
- School of Pharmacy, Lanzhou University, Tianshui Road No. 222, Lanzhou 730000, PR China
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