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Chen J, Liu Y, Mahadevan R. Genetic Engineering of Acidithiobacillus ferridurans Using CRISPR Systems To Mitigate Toxic Release in Biomining. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:12315-12324. [PMID: 37556825 DOI: 10.1021/acs.est.3c02492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/11/2023]
Abstract
Biomining processes utilize microorganisms, such as Acidithiobacillus, to extract valuable metals by producing sulfuric acid and ferric ions that dissolve sulfidic minerals. However, excessive production of these compounds can result in metal structure corrosion and groundwater contamination. Synthetic biology offers a promising solution to improve Acidithiobacillus strains for sustainable, eco-friendly, and cost-effective biomining, but genetic engineering of these slow-growing microorganisms is challenging with current inefficient and time-consuming methods. To address this, we established a CRISPR-dCas9 system for gene knockdown in A. ferridurans JAGS, successfully downregulating the transcriptional levels of two genes involved in sulfur oxidation. More importantly, we constructed an all-in-one CRISPR-Cas9 system for fast and efficient genome editing in A. ferridurans JAGS, achieving seamless gene deletion (HdrB3), promoter substitution (Prus to Ptac), and exogenous gene insertion (GFP). Additionally, we created a HdrB-Rus double-edited strain and performed biomining experiments to extract Ni from pyrrhotite tailings. The engineered strain demonstrated a similar Ni recovery rate to wild-type A. ferridurans JAGS but with significantly lower production of iron ions and sulfuric acid in leachate. These high-efficient CRISPR systems provide a powerful tool for studying gene functions and creating useful recombinants for synthetic biology-assisted biomining applications in the future.
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Affiliation(s)
- Jinjin Chen
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E5, Canada
- Department of Chemical Engineering, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Yilan Liu
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E5, Canada
- Department of Chemical Engineering, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Radhakrishnan Mahadevan
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E5, Canada
- Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada
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Inaba Y, Kernan T, West AC, Banta S. Dispersion of sulfur creates a valuable new growth medium formulation that enables earlier sulfur oxidation in relation to iron oxidation in Acidithiobacillus ferrooxidans cultures. Biotechnol Bioeng 2021; 118:3225-3238. [PMID: 34086346 DOI: 10.1002/bit.27847] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 05/28/2021] [Accepted: 06/01/2021] [Indexed: 01/19/2023]
Abstract
Acidithiobacillus ferrooxidans is an acidophilic chemolithoautotroph that is commonly reported to exhibit diauxic population growth behavior where ferrous iron is oxidized before elemental sulfur when both are available, despite the higher energy content of sulfur. We have discovered sulfur dispersion formulations that enables sulfur oxidation before ferrous iron oxidation. The oxidation of dispersed sulfur can lower the culture pH within days below the range where aerobic ferrous iron oxidation can occur. Thus, ferric iron reduction can be observed quickly which had previously been reported over extended incubation periods with untreated sulfur. Therefore, we demonstrate that this substrate utilization pattern is strongly dependent on the cell loading in relation to sulfur concentration, sulfur surface hydrophobicity, and the pH of the culture. Our dispersed sulfur formulation, lig-sulfur, can be used to support the rapid antibiotic selection of plasmid-transformed cells, which is not possible in liquid cultures where ferrous iron is the main source of energy for these acidophiles. Furthermore, we find that media containing lig-sulfur supports higher production of green fluorescent protein compared to media containing ferrous iron. The use of dispersed sulfur is a valuable new tool for the development of engineered A. ferrooxidans strains and it provides a new method to control iron and sulfur oxidation behaviors.
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Affiliation(s)
- Yuta Inaba
- Department of Chemical Engineering, Columbia University, New York, USA
| | - Timothy Kernan
- Department of Chemical Engineering, Columbia University, New York, USA
| | - Alan C West
- Department of Chemical Engineering, Columbia University, New York, USA
| | - Scott Banta
- Department of Chemical Engineering, Columbia University, New York, USA
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In Vitro Assessment of Antimicrobial Resistance Dissemination Dynamics during Multidrug-Resistant-Bacterium Invasion Events by Using a Continuous-Culture Device. Appl Environ Microbiol 2021; 87:AEM.02659-20. [PMID: 33361364 DOI: 10.1128/aem.02659-20] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 12/11/2020] [Indexed: 11/20/2022] Open
Abstract
Antimicrobial-resistant pathogens display significant public health threats by causing difficulties in clinical treatment of bacterial infection. Antimicrobial resistance (AMR) is transmissible between bacteria, significantly increasing the appearance of antimicrobial-resistant pathogens and aggravating the AMR problem. In this work, the dissemination dynamics of AMR from invading multidrug-resistant (MDR) Escherichia coli to a community of pathogenic Salmonella enterica was investigated using a continuous-culture device, and the behaviors of dissemination dynamics under different levels of antibiotic stress were investigated. Three MDR E. coli invasion events were analyzed in this work: MDR E. coli-S. enterica cocolonization, MDR E. coli invasion after antibiotic treatment of S. enterica, and MDR E. coli invasion before antibiotic treatment of S. enterica It was found that both horizontal gene transfer (HGT) and vertical gene transfer (VGT) play significant roles in AMR dissemination, although different processes contribute differently under different circumstances, that environmental levels of antibiotics promote AMR dissemination by enhancing HGT rather than leading to selective advantage for resistant bacteria, and that early invasion of MDR E. coli completely and quickly sabotages the effectiveness of antibiotic treatment. These findings contribute to understanding the drivers of AMR dissemination under different antibiotic stresses, the detrimental impact of environmental tetracycline contamination, and the danger of nosocomial presence and dissemination of MDR nonpathogens.IMPORTANCE Antimicrobial resistance poses a grave threat to public health and reduces the effectiveness of antimicrobial drugs in treating bacterial infections. Antimicrobial resistance is transmissible, either by horizontal gene transfer between bacteria or by vertical gene transfer following inheritance of genetic traits. The dissemination dynamics and behaviors of this threat, however, have not been rigorously investigated. In this work, with a continuous-culture device, we studied antimicrobial resistance dissemination processes by simulating antimicrobial-resistant Escherichia coli invasion to a pathogenic Salmonella enterica community. Using this novel tool, we provide evidence on the drivers of antimicrobial resistance dissemination, on the detrimental impact of environmental antibiotic contamination, and on the danger of antimicrobial resistance in hospitals, even if what harbors the antimicrobial resistance is not a pathogen. This work furthers our understanding of antimicrobial resistance and its dissemination between bacteria and of antibiotic therapy, our most powerful tool against bacterial infection.
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Application of Firefly Luciferase (Luc) as a Reporter Gene for the Chemoautotrophic and Acidophilic Acidithiobacillus spp. Curr Microbiol 2020; 77:3724-3730. [PMID: 32945904 DOI: 10.1007/s00284-020-02195-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 09/03/2020] [Indexed: 10/23/2022]
Abstract
Acidithiobacillus spp. are the most active bacteria in bioleaching and bioremediation, because of their remarkable extreme environmental adaptabilities and unique metabolic characteristics. The researches on regulatory mechanisms of energy metabolism and stress resistance are critical for the understanding and application of Acidithiobacillus spp. However, the lack of an ideal reporter gene has become an obstacle for studying genes expression and regulatory mechanism in these chemoautotrophic bacteria. In this study, we reported the firefly luciferase as a reporter gene for Acidithiobacillus caldus (A. caldus) and created a firefly luciferase (Luc) reporter system. The Luc system was applied for the quantitative analysis of the transcription strength of the promoters of tetH gene and the feoA gene in A. caldus. Moreover, the regulating effect of ferric uptake regulator (Fur) on the feoP gene in A. caldus was determined using the Luc system. The Luc reporter system is not only used in the study of regulatory mechanism of A. caldus, but also applied in the researches of other Acidithiobacillus species. Therefore, this study provides a new useful tool for the studies on the molecular biological mechanism and synthetic biological modification of these chemoautotrophic bacteria, which would promote the industrial application of Acidithiobacillus spp.
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Jeannot K, Danassie M, Triponney P, Bour M, Gueudet T, Beyrouthy R, Bonnet R, Plésiat P. A novel IncQ plasmid carrying geneblaCTX-M-3 inPseudomonas aeruginosa. J Antimicrob Chemother 2018; 74:823-825. [DOI: 10.1093/jac/dky454] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Affiliation(s)
- Katy Jeannot
- Centre National de Référence de la Résistance aux Antibiotiques, Centre Hospitalier Universitaire de Besançon, Besançon, France
- UMR6249 CNRS Chrono-Environnement, Université de Franche-Comté, Besançon, France
| | - Marion Danassie
- Centre National de Référence de la Résistance aux Antibiotiques, Centre Hospitalier Universitaire de Besançon, Besançon, France
| | - Pauline Triponney
- Centre National de Référence de la Résistance aux Antibiotiques, Centre Hospitalier Universitaire de Besançon, Besançon, France
| | - Maxime Bour
- Centre National de Référence de la Résistance aux Antibiotiques, Centre Hospitalier Universitaire de Besançon, Besançon, France
| | | | - Racha Beyrouthy
- Clermont Université, Université d'Auvergne, Inserm U1071, INRA USC2018, Clermont-Ferrand, France
- CHU Clermont-Ferrand, Laboratoire de Bactériologie Clinique, Clermont-Ferrand, France
- Centre National de Référence de la Résistance aux Antibiotiques, laboratoire associé, Clermont-Ferrand, France
| | - Richard Bonnet
- Clermont Université, Université d'Auvergne, Inserm U1071, INRA USC2018, Clermont-Ferrand, France
- CHU Clermont-Ferrand, Laboratoire de Bactériologie Clinique, Clermont-Ferrand, France
- Centre National de Référence de la Résistance aux Antibiotiques, laboratoire associé, Clermont-Ferrand, France
| | - Patrick Plésiat
- Centre National de Référence de la Résistance aux Antibiotiques, Centre Hospitalier Universitaire de Besançon, Besançon, France
- UMR6249 CNRS Chrono-Environnement, Université de Franche-Comté, Besançon, France
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Transposase-Mediated Chromosomal Integration of Exogenous Genes in Acidithiobacillus ferrooxidans. Appl Environ Microbiol 2018; 84:AEM.01381-18. [PMID: 30143507 DOI: 10.1128/aem.01381-18] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 08/20/2018] [Indexed: 01/21/2023] Open
Abstract
The development of Acidithiobacillus ferrooxidans as a non-model host organism for synthetic biology is hampered by a lack of genetic tools and techniques. New plating and liquid-based selection methods were developed to improve the identification of transformed cell lines. Enabled by these methods, a hyperactive transposase was used to generate mutants with integrated genes for the expression of the superfolder green fluorescent protein (sfGFP) gene or a 2-keto decarboxylase (KDC) gene, which enabled the production and secretion of isobutyric acid (IBA). An inverse PCR method was used to identify the insertion sites of the KDC gene in several mutants, leading to the identification of a region on the chromosome that may be suitable for future genetic insertions. These results demonstrate that functional exogenous metabolic genes have been chromosomally integrated into A. ferrooxidans, and this advance will facilitate the future development of these cells for new biotechnology applications.IMPORTANCE Acidithiobacillus ferrooxidans is an iron- and sulfur-oxidizing chemolithoautotroph and is a key member of the microbial consortia used in industrial biomining applications. There is interest in exploiting these cells for other metal recovery applications as well as in developing them as unique nonmodel microbial cell factories. Plasmid-driven expression of exogenous genes has been reported, and homologous recombination has been used to knock out some gene expression. Here, new selection protocols facilitated the development of a transposition method for chromosomal integration of exogenous genes into A. ferrooxidans This greatly expands the available genetic toolbox, which will open the door to greater metabolic engineering efforts for these cells.
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Gumulya Y, Boxall NJ, Khaleque HN, Santala V, Carlson RP, Kaksonen AH. In a quest for engineering acidophiles for biomining applications: challenges and opportunities. Genes (Basel) 2018; 9:E116. [PMID: 29466321 PMCID: PMC5852612 DOI: 10.3390/genes9020116] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 02/16/2018] [Accepted: 02/16/2018] [Indexed: 12/27/2022] Open
Abstract
Biomining with acidophilic microorganisms has been used at commercial scale for the extraction of metals from various sulfide ores. With metal demand and energy prices on the rise and the concurrent decline in quality and availability of mineral resources, there is an increasing interest in applying biomining technology, in particular for leaching metals from low grade minerals and wastes. However, bioprocessing is often hampered by the presence of inhibitory compounds that originate from complex ores. Synthetic biology could provide tools to improve the tolerance of biomining microbes to various stress factors that are present in biomining environments, which would ultimately increase bioleaching efficiency. This paper reviews the state-of-the-art tools to genetically modify acidophilic biomining microorganisms and the limitations of these tools. The first part of this review discusses resilience pathways that can be engineered in acidophiles to enhance their robustness and tolerance in harsh environments that prevail in bioleaching. The second part of the paper reviews the efforts that have been carried out towards engineering robust microorganisms and developing metabolic modelling tools. Novel synthetic biology tools have the potential to transform the biomining industry and facilitate the extraction of value from ores and wastes that cannot be processed with existing biomining microorganisms.
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Affiliation(s)
- Yosephine Gumulya
- Commonwealth Scientific and Industrial Research Organisation (CSIRO), Floreat WA 6014, Australia.
| | - Naomi J Boxall
- Commonwealth Scientific and Industrial Research Organisation (CSIRO), Floreat WA 6014, Australia.
| | - Himel N Khaleque
- Commonwealth Scientific and Industrial Research Organisation (CSIRO), Floreat WA 6014, Australia.
| | - Ville Santala
- Laboratory of Chemistry and Bioengineering, Tampere University of Technology (TUT), Tampere, 33101, Finland.
| | - Ross P Carlson
- Department of Chemical and Biological Engineering, Montana State University (MSU), Bozeman, MT 59717, USA.
| | - Anna H Kaksonen
- Commonwealth Scientific and Industrial Research Organisation (CSIRO), Floreat WA 6014, Australia.
- School of Pathology and Laboratory Medicine, University of Western Australia, Crawley, WA 6009, Australia.
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