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Sk S, Bandyopadhyay S, Sarkar C, Das I, Gupta A, Sadangi M, Mondal S, Banerjee M, Vijaykumar G, Behera JN, Konar S, Mandal S, Bera M. Unraveling Multicopper [Cu 3] and [Cu 6] Clusters with Rare μ 3-Sulfato and Linear μ 2-Oxido-Bridges as Potent Antibiofilm Agents against Multidrug-Resistant Staphylococcus aureus. ACS APPLIED BIO MATERIALS 2024; 7:2423-2449. [PMID: 38478915 DOI: 10.1021/acsabm.4c00075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
In this research article, two multicopper [Cu3] and [Cu6] clusters, [Cu3(cpdp)(μ3-SO4)(Cl)(H2O)2]·3H2O (1) and [Cu6(cpdp)2(μ2-O)(Cl)2(H2O)4]·2Cl (2) (H3cpdp = N,N'-bis[2-carboxybenzomethyl]-N,N'-bis[2-pyridylmethyl]-1,3-diaminopropan-2-ol), have been explored as potent antibacterial and antibiofilm agents. Their molecular structures have been determined by a single-crystal X-ray diffraction study, and the compositions have been established by thermal and elemental analyses, including electrospray ionization mass spectrometry. Structural analysis shows that the metallic core of 1 is composed of a trinuclear [Cu3] assembly encapsulating a μ3-SO42- group, whereas the structure of 2 represents a hexanuclear [Cu6] assembly in which two trinuclear [Cu3] motifs are exclusively bridged by a linear μ2-O2- group. The most striking feature of the structure of 2 is the occurrence of an unusual linear oxido-bridge, with the Cu3-O6-Cu3' bridging angle being 180.00°. Whereas 1 can be viewed as an example of a copper(II)-based compound displaying a rare μ3:η1:η1:η1 bridging mode of the SO42- group, 2 is the first example of any copper(II)-based compound showing an unsupported linear Cu-O-Cu oxido-bridge. Employing variable-temperature SQUID magnetometry, the magnetic susceptibility data were measured and analyzed exemplarily for 1 in the temperature range of 2-300 K, revealing the occurrence of antiferromagnetic interactions among the paramagnetic copper centers. Both 1 and 2 exhibited potent antibacterial and antibiofilm activities against methicillin-resistant Staphylococcus aureus (MRSA BAA1717) and the clinically isolated culture of methicillin-resistant S. aureus (MRSA CI1). The mechanism of antibacterial and antibiofilm activities of these multicopper clusters was investigated by analyzing and determining the intracellular reactive oxygen species (ROS) generation, lipid peroxidation, microscopic observation of cell membrane disruption, membrane potential, and leakage of cellular components. Additionally, 1 and 2 showed a synergistic effect with commercially available antibiotics such as vancomycin with enhanced antibacterial activity. However, 1 possesses higher antibacterial, antibiofilm, and antivirulence actions, making it a potent therapeutic agent against both MRSA BAA1717 and MRSA CI1 strains.
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Affiliation(s)
- Sujan Sk
- Department of Chemistry, University of Kalyani, Nadia, Kalyani, West Bengal 741235, India
| | - Shrabasti Bandyopadhyay
- Department of Microbiology, University of Kalyani, Nadia, Kalyani, West Bengal 741235, India
| | - Chandan Sarkar
- Department of Chemistry, University of Kalyani, Nadia, Kalyani, West Bengal 741235, India
| | - Indrajit Das
- Department of Microbiology, University of Kalyani, Nadia, Kalyani, West Bengal 741235, India
| | - Arindam Gupta
- Department of Chemistry, Indian Institute of Science Education and Research, Bhopal, Madhya Pradesh 462066, India
| | - Manisha Sadangi
- School of Chemical Sciences, National Institute of Science Education & Research, An OCC of Homi Bhabha National Institute, Khurda, Bhubaneswar, Odisha 752050, India
| | - Soma Mondal
- Department of Microbiology, College of Medicine & Jawaharlal Nehru Memorial (JNM) Hospital, WBUHS, Nadia, Kalyani, West Bengal 741235, India
| | - Malabika Banerjee
- Cristália Produtos Químicos Farmacêuticos Limited, Rodovia Itapira, Sao Paulo CEP 13970-970, Brazil
| | - Gonela Vijaykumar
- Catalysis and Fine Chemicals Department, CSIR-Indian Institute of Chemical Technology, Hyderabad 500007, India
| | - J N Behera
- School of Chemical Sciences, National Institute of Science Education & Research, An OCC of Homi Bhabha National Institute, Khurda, Bhubaneswar, Odisha 752050, India
| | - Sanjit Konar
- Department of Chemistry, Indian Institute of Science Education and Research, Bhopal, Madhya Pradesh 462066, India
| | - Supratim Mandal
- Department of Microbiology, University of Kalyani, Nadia, Kalyani, West Bengal 741235, India
| | - Manindranath Bera
- Department of Chemistry, University of Kalyani, Nadia, Kalyani, West Bengal 741235, India
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2
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Zhao F, Zhang Q, He L, Yang W, Si M, Liao Q, Yang Z. Molecular level insight of thiocyanate degradation by Pseudomonas putida TDB-1 under a high arsenic and alkaline condition. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 874:162578. [PMID: 36870261 DOI: 10.1016/j.scitotenv.2023.162578] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 02/09/2023] [Accepted: 02/27/2023] [Indexed: 06/18/2023]
Abstract
It is a big challenge to bioremediate thiocyanate pollution in the gold extraction heap leaching tailings and surrounding soils with high contents of arsenic and alkali. Here, a novel thiocyanate-degrading bacterium Pseudomonas putida TDB-1 was successfully applied to completely degrade 1000 mg/L thiocyanate under a high arsenic (400 mg/L) and alkaline condition (pH = 10). It also leached the contents of thiocyanate from 1302.16 to 269.72 mg/kg in the gold extraction heap leaching tailings after 50 h. The maximum transformation rates of S and N in thiocyanate to the two finial products of SO42- and NO3- were 88.98 % and 92.71 %, respectively. Moreover, the genome sequencing confirmed that the biomarker gene of thiocyanate-degrading bacterium, CynS was identified in the strain TDB-1. The bacterial transcriptome revealed that critical genes, such as CynS, CcoNOQP, SoxY, tst, gltBD, arsRBCH and NhaC, etc. in the thiocyanate degradation, S and N metabolisms, and As and alkali resistance were significantly up-regulated in the groups with 300 mg/L SCN- (T300) and with 300 mg/L SCN- and 200 mg/L As (TA300). In addition, the protein-protein interaction network showed that the glutamate synthase encoding by gltB and gltD served as central node to integrate the S and N metabolism pathways with thiocyanate as substrate. The results of our study provide a novel molecular level insight for the dynamic gene expression regulation of thiocyanate degradation by the strain TDB-1 with a severe arsenic and alkaline stress.
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Affiliation(s)
- Feiping Zhao
- Institute of Environmental Science and Engineering, School of Metallurgy and Environment, Central South University, 410083 Changsha, China; Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, 410083 Changsha, China
| | - Qinya Zhang
- Institute of Environmental Science and Engineering, School of Metallurgy and Environment, Central South University, 410083 Changsha, China
| | - Lixu He
- Institute of Environmental Science and Engineering, School of Metallurgy and Environment, Central South University, 410083 Changsha, China
| | - Weichun Yang
- Institute of Environmental Science and Engineering, School of Metallurgy and Environment, Central South University, 410083 Changsha, China; Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, 410083 Changsha, China
| | - Mengying Si
- Institute of Environmental Science and Engineering, School of Metallurgy and Environment, Central South University, 410083 Changsha, China; Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, 410083 Changsha, China
| | - Qi Liao
- Institute of Environmental Science and Engineering, School of Metallurgy and Environment, Central South University, 410083 Changsha, China; Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, 410083 Changsha, China.
| | - Zhihui Yang
- Institute of Environmental Science and Engineering, School of Metallurgy and Environment, Central South University, 410083 Changsha, China; Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, 410083 Changsha, China
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3
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Unusual Cytochrome c552 from Thioalkalivibrio paradoxus: Solution NMR Structure and Interaction with Thiocyanate Dehydrogenase. Int J Mol Sci 2022; 23:ijms23179969. [PMID: 36077365 PMCID: PMC9456337 DOI: 10.3390/ijms23179969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 08/25/2022] [Accepted: 08/27/2022] [Indexed: 11/16/2022] Open
Abstract
The search of a putative physiological electron acceptor for thiocyanate dehydrogenase (TcDH) newly discovered in the thiocyanate-oxidizing bacteria Thioalkalivibrio paradoxus revealed an unusually large, single-heme cytochrome c (CytC552), which was co-purified with TcDH from the periplasm. Recombinant CytC552, produced in Escherichia coli as a mature protein without a signal peptide, has spectral properties similar to the endogenous protein and serves as an in vitro electron acceptor in the TcDH-catalyzed reaction. The CytC552 structure determined by NMR spectroscopy reveals significant differences compared to those of the typical class I bacterial cytochromes c: a high solvent accessible surface area for the heme group and so-called “intrinsically disordered” nature of the histidine-rich N- and C-terminal regions. Comparison of the signal splitting in the heteronuclear NMR spectra of oxidized, reduced, and TcDH-bound CytC552 reveals the heme axial methionine fluxionality. The TcDH binding site on the CytC552 surface was mapped using NMR chemical shift perturbations. Putative TcDH-CytC552 complexes were reconstructed by the information-driven docking approach and used for the analysis of effective electron transfer pathways. The best pathway includes the electron hopping through His528 and Tyr164 of TcDH, and His83 of CytC552 to the heme group in accordance with pH-dependence of TcDH activity with CytC552.
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Tanabe TS, Dahl C. HMS-S-S: a tool for the identification of sulfur metabolism-related genes and analysis of operon structures in genome and metagenome assemblies. Mol Ecol Resour 2022; 22:2758-2774. [PMID: 35579058 DOI: 10.1111/1755-0998.13642] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 04/25/2022] [Accepted: 05/11/2022] [Indexed: 11/26/2022]
Abstract
Sulfur compounds are used in a variety of biological processes including respiration and photosynthesis. Sulfide and sulfur compounds of intermediary oxidation state can serve as electron donors for lithotrophic growth while sulfate, thiosulfate and sulfur are used as electron acceptors in anaerobic respiration. The biochemistry underlying the manifold transformations of inorganic sulfur compounds occurring in sulfur metabolizing prokaryotes is astonishingly complex and knowledge about it has immensely increased over the last years. The advent of next-generation sequencing approaches as well as the significant increase of data availability in public databases has driven focus of environmental microbiology to probing the metabolic capacity of microbial communities by analysis of this sequence data. To facilitate these analyses, we created HMS-S-S, a comprehensive equivalogous hidden Markov model (HMM)-supported tool. Protein sequences related to sulfur compound oxidation, reduction, transport and intracellular transfer are efficiently detected and related enzymes involved in dissimilatory sulfur oxidation as opposed to sulfur compound reduction can be confidently distinguished. HMM search results are coupled to corresponding genes, which allows analysis of co-occurrence, synteny and genomic neighborhood. The HMMs were validated on an annotated test dataset and by cross-validation. We also proved its performance by exploring meta-assembled genomes isolated from samples from environments with active sulfur cycling, including members of the cable bacteria, novel Acidobacteria and assemblies from a sulfur-rich glacier, and were able to replicate and extend previous reports.
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Affiliation(s)
- Tomohisa Sebastian Tanabe
- Institut für Mikrobiologie & Biotechnologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany
| | - Christiane Dahl
- Institut für Mikrobiologie & Biotechnologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany
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5
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Oshiki M, Fukushima T, Kawano S, Nakagawa J. Endpoint Recombinase Polymerase Amplification (RPA) Assay for Enumeration of Thiocyanate-degrading Bacteria. Microbes Environ 2022; 37. [PMID: 35264493 PMCID: PMC8958297 DOI: 10.1264/jsme2.me21073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
An endpoint recombination amplification reaction (RPA) assay for assessing the abundance of the gene encoding thiocyanate dehydrogenase (TcDH) in Thiohalobacter has been developed. The RPA reaction was performed at 37°C for 30 min, terminated by the addition of sodium dodecyl sulfate (SDS) solution, and the DNA concentration of the RPA product was fluorometrically measured. The abundance of TcDH in 22 activated sludge samples and 7 thiocyanate-degrading enrichment cultures ranged between 2.5×103 and 1.5×106 copies μL–1, showing a linear relationship (R2=0.83) with those measured using a conventional quantitative PCR assay.
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Affiliation(s)
- Mamoru Oshiki
- Department of Civil Engineering, National Institute of Technology.,Division of Environmental Engineering, Faculty of Engineering, Hokkaido University
| | - Toshikazu Fukushima
- Advanced Technology Research Laboratories, Research & Development, Nippon Steel Corporation
| | - Shuichi Kawano
- Department of Computer and Network Engineering Graduate School of Informatics and Engineering, The University of Electro-Communications
| | - Junichi Nakagawa
- Advanced Technology Research Laboratories, Research & Development, Nippon Steel Corporation
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6
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Redox-Active Metal Ions and Amyloid-Degrading Enzymes in Alzheimer's Disease. Int J Mol Sci 2021; 22:ijms22147697. [PMID: 34299316 PMCID: PMC8307724 DOI: 10.3390/ijms22147697] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 07/11/2021] [Accepted: 07/16/2021] [Indexed: 12/11/2022] Open
Abstract
Redox-active metal ions, Cu(I/II) and Fe(II/III), are essential biological molecules for the normal functioning of the brain, including oxidative metabolism, synaptic plasticity, myelination, and generation of neurotransmitters. Dyshomeostasis of these redox-active metal ions in the brain could cause Alzheimer’s disease (AD). Thus, regulating the levels of Cu(I/II) and Fe(II/III) is necessary for normal brain function. To control the amounts of metal ions in the brain and understand the involvement of Cu(I/II) and Fe(II/III) in the pathogenesis of AD, many chemical agents have been developed. In addition, since toxic aggregates of amyloid-β (Aβ) have been proposed as one of the major causes of the disease, the mechanism of clearing Aβ is also required to be investigated to reveal the etiology of AD clearly. Multiple metalloenzymes (e.g., neprilysin, insulin-degrading enzyme, and ADAM10) have been reported to have an important role in the degradation of Aβ in the brain. These amyloid degrading enzymes (ADE) could interact with redox-active metal ions and affect the pathogenesis of AD. In this review, we introduce and summarize the roles, distributions, and transportations of Cu(I/II) and Fe(II/III), along with previously invented chelators, and the structures and functions of ADE in the brain, as well as their interrelationships.
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Khrenova MG, Soloveva AY, Varfolomeeva LA, Tikhonova TV, Popov VO. The O to S substitution in urea brings inhibition activity against thiocyanate dehydrogenase. MENDELEEV COMMUNICATIONS 2021. [DOI: 10.1016/j.mencom.2021.05.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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8
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Khrenova MG, Soloveva AY, Varfolomeeva LA, Tikhonova TV, Popov VO. The O to S substitution in urea brings inhibition activity against thiocyanate dehydrogenase. MENDELEEV COMMUNICATIONS 2021. [DOI: 10.1016/j.mencom.2021.04.030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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9
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Tikhonova TV, Lilina AV, Osipov EM, Shipkov NS, Dergousova NI, Kulikova OG, Popov VO. Catalytic Properties of Flavocytochrome c Sulfide Dehydrogenase from Haloalkaliphilic Bacterium Thioalkalivibrio paradoxus. BIOCHEMISTRY (MOSCOW) 2021; 86:361-369. [PMID: 33838635 DOI: 10.1134/s0006297921030111] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Flavocytochrome c sulfide dehydrogenase (FCC) is one of the central enzymes of the respiratory chain in sulfur-oxidizing bacteria. FCC catalyzes oxidation of sulfide and polysulfide ions to elemental sulfur accompanied by electron transfer to cytochrome c. The catalytically active form of the enzyme is a non-covalently linked heterodimer composed of flavin- and heme-binding subunits. The Thioalkalivibrio paradoxus ARh1 genome contains five copies of genes encoding homologous FCCs with an amino acid sequence identity from 36 to 54%. When growing on thiocyanate or thiosulfate as the main energy source, the bacterium synthesizes products of different copies of FCC genes. In this work, we isolated and characterized FCC synthesized during the growth of Tv. paradoxus on thiocyanate. FCC was shown to oxidize exclusively sulfide but not other reduced sulfur compounds, such as thiosulfate, sulfite, tetrathionate, and sulfur, and it also does not catalyze the reverse reaction of sulfur reduction to sulfide. Kinetic parameters of the sulfide oxidation reaction are characterized.
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Affiliation(s)
- Tamara V Tikhonova
- Bach Institute of Biochemistry, Research Centre of Biotechnology, Russian Academy of Sciences, Moscow, 119071, Russia.
| | - Anastasiya V Lilina
- Bach Institute of Biochemistry, Research Centre of Biotechnology, Russian Academy of Sciences, Moscow, 119071, Russia
| | - Evgenii M Osipov
- Bach Institute of Biochemistry, Research Centre of Biotechnology, Russian Academy of Sciences, Moscow, 119071, Russia
| | - Nikolay S Shipkov
- Bach Institute of Biochemistry, Research Centre of Biotechnology, Russian Academy of Sciences, Moscow, 119071, Russia
| | - Nataliya I Dergousova
- Bach Institute of Biochemistry, Research Centre of Biotechnology, Russian Academy of Sciences, Moscow, 119071, Russia
| | - Olga G Kulikova
- Bach Institute of Biochemistry, Research Centre of Biotechnology, Russian Academy of Sciences, Moscow, 119071, Russia
| | - Vladimir O Popov
- Bach Institute of Biochemistry, Research Centre of Biotechnology, Russian Academy of Sciences, Moscow, 119071, Russia
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10
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Huddy RJ, Sachdeva R, Kadzinga F, Kantor RS, Harrison STL, Banfield JF. Thiocyanate and Organic Carbon Inputs Drive Convergent Selection for Specific Autotrophic Afipia and Thiobacillus Strains Within Complex Microbiomes. Front Microbiol 2021; 12:643368. [PMID: 33897653 PMCID: PMC8061750 DOI: 10.3389/fmicb.2021.643368] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 03/09/2021] [Indexed: 01/14/2023] Open
Abstract
Thiocyanate (SCN–) contamination threatens aquatic ecosystems and pollutes vital freshwater supplies. SCN–-degrading microbial consortia are commercially adapted for remediation, but the impact of organic amendments on selection within SCN–-degrading microbial communities has not been investigated. Here, we tested whether specific strains capable of degrading SCN– could be reproducibly selected for based on SCN– loading and the presence or absence of added organic carbon. Complex microbial communities derived from those used to treat SCN–-contaminated water were exposed to systematically increased input SCN concentrations in molasses-amended and -unamended reactors and in reactors switched to unamended conditions after establishing the active SCN–-degrading consortium. Five experiments were conducted over 790 days, and genome-resolved metagenomics was used to resolve community composition at the strain level. A single Thiobacillus strain proliferated in all reactors at high loadings. Despite the presence of many Rhizobiales strains, a single Afipia variant dominated the molasses-free reactor at moderately high loadings. This strain is predicted to break down SCN– using a novel thiocyanate desulfurase, oxidize resulting reduced sulfur, degrade product cyanate to ammonia and CO2 via cyanate hydratase, and fix CO2 via the Calvin–Benson–Bassham cycle. Removal of molasses from input feed solutions reproducibly led to dominance of this strain. Although sustained by autotrophy, reactors without molasses did not stably degrade SCN– at high loading rates, perhaps due to loss of biofilm-associated niche diversity. Overall, convergence in environmental conditions led to convergence in the strain composition, although reactor history also impacted the trajectory of community compositional change.
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Affiliation(s)
- Robert J Huddy
- Centre for Bioprocess Engineering Research, University of Cape Town, Cape Town, South Africa.,Future Water Institute, University of Cape Town, Cape Town, South Africa
| | - Rohan Sachdeva
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA, United States
| | - Fadzai Kadzinga
- Centre for Bioprocess Engineering Research, University of Cape Town, Cape Town, South Africa.,Future Water Institute, University of Cape Town, Cape Town, South Africa
| | - Rose S Kantor
- Department of Earth and Planetary Science, University of California, Berkeley, Berkeley, CA, United States
| | - Susan T L Harrison
- Centre for Bioprocess Engineering Research, University of Cape Town, Cape Town, South Africa.,Future Water Institute, University of Cape Town, Cape Town, South Africa
| | - Jillian F Banfield
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA, United States.,Department of Earth and Planetary Science, University of California, Berkeley, Berkeley, CA, United States.,Department of Environmental Science, Policy, and Management, University of California, Berkeley, Berkeley, CA, United States.,School of Earth Sciences, University of Melbourne, Melbourne, VIC, Australia
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11
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Shafiei F, Watts MP, Pajank L, Moreau JW. The effect of heavy metals on thiocyanate biodegradation by an autotrophic microbial consortium enriched from mine tailings. Appl Microbiol Biotechnol 2020; 105:417-427. [PMID: 33263791 PMCID: PMC7778618 DOI: 10.1007/s00253-020-10983-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 10/17/2020] [Accepted: 10/26/2020] [Indexed: 11/28/2022]
Abstract
Abstract Bioremediation systems represent an environmentally sustainable approach to degrading industrially generated thiocyanate (SCN−), with low energy demand and operational costs and high efficiency and substrate specificity. However, heavy metals present in mine tailings effluent may hamper process efficiency by poisoning thiocyanate-degrading microbial consortia. Here, we experimentally tested the tolerance of an autotrophic SCN−-degrading bacterial consortium enriched from gold mine tailings for Zn, Cu, Ni, Cr, and As. All of the selected metals inhibited SCN− biodegradation to different extents, depending on concentration. At pH of 7.8 and 30 °C, complete inhibition of SCN− biodegradation by Zn, Cu, Ni, and Cr occurred at 20, 5, 10, and 6 mg L−1, respectively. Lower concentrations of these metals decreased the rate of SCN− biodegradation, with relatively long lag times. Interestingly, the microbial consortium tolerated As even at 500 mg L−1, although both the rate and extent of SCN− biodegradation were affected. Potentially, the observed As tolerance could be explained by the origin of our microbial consortium in tailings derived from As-enriched gold ore (arsenopyrite). This study highlights the importance of considering metal co-contamination in bioreactor design and operation for SCN− bioremediation at mine sites. Key points • Both the efficiency and rate of SCN−biodegradation were inhibited by heavy metals, to different degrees depending on type and concentration of metal. • The autotrophic microbial consortium was capable of tolerating high concentrations of As, potential having adapted to higher As levels derived from the tailings source. Supplementary Information The online version contains supplementary material available at 10.1007/s00253-020-10983-4.
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Affiliation(s)
- Farhad Shafiei
- School of Earth Sciences, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Mathew P Watts
- School of Earth Sciences, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Lukas Pajank
- School of Earth Sciences, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - John W Moreau
- School of Earth Sciences, The University of Melbourne, Parkville, VIC, 3010, Australia. .,School of Geographical & Earth Sciences, University of Glasgow, Glasgow, G12 8QQ, UK.
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