1
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Jung H, Inaba Y, Banta S. CRISPR/dCas12a knock-down of Acidithiobacillus ferrooxidans electron transport chain bc 1 complexes enables enhanced metal sulfide bioleaching. J Biol Chem 2024:107703. [PMID: 39173952 DOI: 10.1016/j.jbc.2024.107703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2024] [Revised: 08/13/2024] [Accepted: 08/16/2024] [Indexed: 08/24/2024] Open
Abstract
Acidithiobacillus ferrooxidans is an acidophilic chemolithoautotroph that plays an important role in biogeochemical iron and sulfur cycling and is a member of the consortia used in industrial hydrometallurgical processing of copper. Metal sulfide bioleaching is catalyzed by the regeneration of ferric iron, however, bioleaching of chalcopyrite, the dominant unmined form of copper on Earth, is inhibited by surface passivation. Here, we report the implementation of CRISPR interference (CRISPRi) using the catalytically inactive Cas12a (dCas12a) in A. ferrooxidans to knockdown the expression of genes in the petI and petII operons. These operons encode bc1 complex proteins and knockdown of these genes enabled the manipulation (enhancement or repression) of iron oxidation. The petB2 gene knockdown strain enhanced iron oxidation, leading to enhanced pyrite and chalcopyrite oxidation, which correlated with reduced biofilm formation and decreased surface passivation of the minerals. These findings highlight the utility of CRISPRi/dCas12a technology for engineering A. ferrooxidans while unveiling a new strategy to manipulate and improve bioleaching efficiency.
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Affiliation(s)
- Heejung Jung
- Department of Chemical Engineering, Columbia University, New York, New York
| | - Yuta Inaba
- Department of Chemical Engineering, Columbia University, New York, New York
| | - Scott Banta
- Department of Chemical Engineering, Columbia University, New York, New York.
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2
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Jung H, Su Z, Inaba Y, West AC, Banta S. Genetic Modification of Acidithiobacillus ferrooxidans for Rare-Earth Element Recovery under Acidic Conditions. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:19902-19911. [PMID: 37983372 DOI: 10.1021/acs.est.3c05772] [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: 11/22/2023]
Abstract
As global demands for rare-earth elements (REEs) continue to grow, the biological recovery of REEs has been explored as a promising strategy, driven by potential economic and environmental benefits. It is known that calcium-binding domains, including helix-loop-helix EF hands and repeats-in-toxin (RTX) domains, can bind lanthanide ions due to their similar ionic radii and coordination preference to calcium. Recently, the lanmodulin protein from Methylorubrum extorquens was reported, which has evolved a high affinity for lanthanide ions over calcium. Acidithiobacillus ferrooxidans is a chemolithoautotrophic acidophile, which has been explored for use in bioleaching for metal recovery. In this report, A. ferrooxidans was engineered for the recombinant intracellular expression of lanmodulin. In addition, an RTX domain from the adenylate cyclase protein of Bordetella pertussis, which has previously been shown to bind Tb3+, was expressed periplasmically via fusion with the endogenous rusticyanin protein. The binding of lanthanides (Tb3+, Pr3+, Nd3+, and La3+) was improved by up to 4-fold for cells expressing lanmodulin and 13-fold for cells expressing the RTX domains in both pure and mixed metal solutions. Interestingly, the presence of lanthanides in the growth media enhanced protein expression, likely by influencing protein stability. Both engineered cell lines exhibited higher recoveries and selectivities for four tested lanthanides (Tb3+, Pr3+, Nd3+, and La3+) over non-REEs (Fe2+ and Co2+) in a synthetic magnet leachate, demonstrating the potential of these new strains for future REE reclamation and recycling applications.
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Affiliation(s)
- Heejung Jung
- Department of Chemical Engineering, Columbia University, 500 West 120th Street, New York, New York 10027, United States
| | - Zihang Su
- Department of Chemical Engineering, Columbia University, 500 West 120th Street, New York, New York 10027, United States
| | - Yuta Inaba
- Department of Chemical Engineering, Columbia University, 500 West 120th Street, New York, New York 10027, United States
| | - Alan C West
- Department of Chemical Engineering, Columbia University, 500 West 120th Street, New York, New York 10027, United States
| | - Scott Banta
- Department of Chemical Engineering, Columbia University, 500 West 120th Street, New York, New York 10027, United States
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3
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Jung H, Inaba Y, West AC, Banta S. Overexpression of quorum sensing genes in Acidithiobacillus ferrooxidans enhances cell attachment and covellite bioleaching. BIOTECHNOLOGY REPORTS (AMSTERDAM, NETHERLANDS) 2023; 38:e00789. [PMID: 36923508 PMCID: PMC10009093 DOI: 10.1016/j.btre.2023.e00789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 02/21/2023] [Accepted: 02/24/2023] [Indexed: 02/27/2023]
Abstract
Cell adhesion is generally a prerequisite to the microbial bioleaching of sulfide minerals, and surface biofilm formation is modulated via quorum sensing (QS) communication. We explored the impact of the overexpression of endogenous QS machinery on the covellite bioleaching capabilities of Acidithiobacillus ferrooxidans, a representative acidophilic chemolithoautotrophic bacterium. Cells were engineered to overexpress the endogenous qs-I operon or just the afeI gene under control of the tac promoter. Both strains exhibited increased transcriptional gene expression of afeI and improved cell adhesion to covellite, including increased production of extracellular polymeric substances and increased biofilm formation. Under low iron conditions, the improved bioleaching of covellite was more evident when afeI was overexpressed alone as compared to the native operon. These observations demonstrate the potential for the genetic modulation of QS as a mechanism for increasing the bioleaching efficiency of covellite, and potentially other copper sulfide minerals.
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Affiliation(s)
- Heejung Jung
- Department of Chemical Engineering, Columbia University, 500 West 120th Street, New York, NY 10027, USA
| | - Yuta Inaba
- Department of Chemical Engineering, Columbia University, 500 West 120th Street, New York, NY 10027, USA
| | - Alan C West
- Department of Chemical Engineering, Columbia University, 500 West 120th Street, New York, NY 10027, USA
| | - Scott Banta
- Department of Chemical Engineering, Columbia University, 500 West 120th Street, New York, NY 10027, USA
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4
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Kanao T, Kunihisa T, Ohgimoto S, Ito M, Murakami C, Nakayama H, Tamura T, Kamimura K. Recombinant expression using the tetrathionate hydrolase promoter in Acidithiobacillus ferrooxidans. J Biosci Bioeng 2023; 135:176-181. [PMID: 36635106 DOI: 10.1016/j.jbiosc.2022.12.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 12/07/2022] [Accepted: 12/09/2022] [Indexed: 01/12/2023]
Abstract
In the iron- and sulfur-oxidizing acidophilic chemolithoautotrophic bacterium, Acidithiobacillus ferrooxidans, tetrathionate hydrolase gene (Af-tth) is highly expressed during tetrathionate growth. The expression levels of Af-tth were specifically determined by quantitative reverse transcription-polymerase chain reaction and the expression ratios of S0/Fe2+ and S4O62-/Fe2+ were found to be 68 ± 21 and 181 ± 5, respectively. The transcriptional start site was identified by primer extension. Promoter regions of Af-tth were cloned into the expression shuttle vector pMPJC and GFP gene was under the direction of the regions. Green fluorescence was observed by UV irradiation in recombinant A. ferrooxidans harboring the plasmid colonies grown on tetrathionate. Furthermore, His-tagged Af-Tth was synthesized in the recombinant cells grown on tetrathionate. Recombinant, His-tagged Af-Tth in an active form, was rapidly purified through metal-affinity column chromatography, although recombinant Af-Tth was synthesized in the inclusion bodies of Escherichia coli and acid-refolding treatment was necessary to recover the activity. The specific activity of purified Af-Tth from recombinant A. ferrooxidans (2.2 ± 0.37 U mg-1) was similar to that of acid-refolded Af-Tth from recombinant E. coli (2.5 ± 0.18 U mg-1). This method can be applied not only to heterologous expression but also to homologous expression of target genes for modification or specific mutation in A. ferrooxidans cells.
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Affiliation(s)
- Tadayoshi Kanao
- Department of Biofunctional Chemistry, Division of Agricultural and Life Science, Graduate School of Environmental and Life Science, Okayama University, 3-1-1 Tsushima-Naka, Kita-ku, Okayama 700-8530, Japan.
| | - Tomoki Kunihisa
- Department of Biofunctional Chemistry, Division of Agricultural and Life Science, Graduate School of Environmental and Life Science, Okayama University, 3-1-1 Tsushima-Naka, Kita-ku, Okayama 700-8530, Japan
| | - Shuji Ohgimoto
- Department of Biofunctional Chemistry, Division of Agricultural and Life Science, Graduate School of Environmental and Life Science, Okayama University, 3-1-1 Tsushima-Naka, Kita-ku, Okayama 700-8530, Japan
| | - Megumi Ito
- Department of Biofunctional Chemistry, Division of Agricultural and Life Science, Graduate School of Environmental and Life Science, Okayama University, 3-1-1 Tsushima-Naka, Kita-ku, Okayama 700-8530, Japan
| | - Chisa Murakami
- Department of Biofunctional Chemistry, Division of Agricultural and Life Science, Graduate School of Environmental and Life Science, Okayama University, 3-1-1 Tsushima-Naka, Kita-ku, Okayama 700-8530, Japan
| | - Hisayuki Nakayama
- Department of Biofunctional Chemistry, Division of Agricultural and Life Science, Graduate School of Environmental and Life Science, Okayama University, 3-1-1 Tsushima-Naka, Kita-ku, Okayama 700-8530, Japan
| | - Takashi Tamura
- Department of Biofunctional Chemistry, Division of Agricultural and Life Science, Graduate School of Environmental and Life Science, Okayama University, 3-1-1 Tsushima-Naka, Kita-ku, Okayama 700-8530, Japan
| | - Kazuo Kamimura
- Department of Biofunctional Chemistry, Division of Agricultural and Life Science, Graduate School of Environmental and Life Science, Okayama University, 3-1-1 Tsushima-Naka, Kita-ku, Okayama 700-8530, Japan
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5
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Chen J, Liu Y, Diep P, Mahadevan R. Genetic engineering of extremely acidophilic Acidithiobacillus species for biomining: Progress and perspectives. JOURNAL OF HAZARDOUS MATERIALS 2022; 438:129456. [PMID: 35777147 DOI: 10.1016/j.jhazmat.2022.129456] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 06/19/2022] [Accepted: 06/22/2022] [Indexed: 06/15/2023]
Abstract
With global demands for mineral resources increasing and ore grades decreasing, microorganisms have been increasingly deployed in biomining applications to recover valuable metals particularly from normally considered waste, such as low-grade ores and used consumer electronics. Acidithiobacillus are a genus of chemolithoautotrophic extreme acidophiles that are commonly found in mining process waters and acid mine drainage, which have been reported in several studies to aid in metal recovery from bioremediation of metal-contaminated sites. Compared to conventional mineral processing technologies, biomining is often cited as a more sustainable and environmentally friendly process, but long leaching cycles and low extraction efficiency are main disadvantages that have hampered its industrial applications. Genetic engineering is a powerful technology that can be used to enhance the performance of microorganisms, such as Acidithiobacillus species. In this review, we compile existing data on Acidithiobacillus species' physiological traits and genomic characteristics, progresses in developing genetic tools to engineer them: plasmids, shutter vectors, transformation methods, selection markers, promoters and reporter systems developed, and genome editing techniques. We further propose genetic engineering strategies for enhancing biomining efficiency of Acidithiobacillus species and provide our perspectives on their future applications.
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Affiliation(s)
- Jinjin Chen
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Canada
| | - Yilan Liu
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Canada
| | - Patrick Diep
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Canada
| | - Radhakrishnan Mahadevan
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Canada; Institute of Biomedical Engineering, University of Toronto, Toronto, Canada.
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6
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AHL-mediated quorum sensing to regulate bacterial substance and energy metabolism: A review. Microbiol Res 2022; 262:127102. [DOI: 10.1016/j.micres.2022.127102] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 06/08/2022] [Accepted: 06/22/2022] [Indexed: 01/09/2023]
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7
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González-Rosales C, Vergara E, Dopson M, Valdés JH, Holmes DS. Integrative Genomics Sheds Light on Evolutionary Forces Shaping the Acidithiobacillia Class Acidophilic Lifestyle. Front Microbiol 2022; 12:822229. [PMID: 35242113 PMCID: PMC8886135 DOI: 10.3389/fmicb.2021.822229] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 12/30/2021] [Indexed: 01/22/2023] Open
Abstract
Extreme acidophiles thrive in environments rich in protons (pH values <3) and often high levels of dissolved heavy metals. They are distributed across the three domains of the Tree of Life including members of the Proteobacteria. The Acidithiobacillia class is formed by the neutrophilic genus Thermithiobacillus along with the extremely acidophilic genera Fervidacidithiobacillus, Igneacidithiobacillus, Ambacidithiobacillus, and Acidithiobacillus. Phylogenomic reconstruction revealed a division in the Acidithiobacillia class correlating with the different pH optima that suggested that the acidophilic genera evolved from an ancestral neutrophile within the Acidithiobacillia. Genes and mechanisms denominated as "first line of defense" were key to explaining the Acidithiobacillia acidophilic lifestyle including preventing proton influx that allows the cell to maintain a near-neutral cytoplasmic pH and differ from the neutrophilic Acidithiobacillia ancestors that lacked these systems. Additional differences between the neutrophilic and acidophilic Acidithiobacillia included the higher number of gene copies in the acidophilic genera coding for "second line of defense" systems that neutralize and/or expel protons from cell. Gain of genes such as hopanoid biosynthesis involved in membrane stabilization at low pH and the functional redundancy for generating an internal positive membrane potential revealed the transition from neutrophilic properties to a new acidophilic lifestyle by shaping the Acidithiobacillaceae genomic structure. The presence of a pool of accessory genes with functional redundancy provides the opportunity to "hedge bet" in rapidly changing acidic environments. Although a core of mechanisms for acid resistance was inherited vertically from an inferred neutrophilic ancestor, the majority of mechanisms, especially those potentially involved in resistance to extremely low pH, were obtained from other extreme acidophiles by horizontal gene transfer (HGT) events.
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Affiliation(s)
- Carolina González-Rosales
- Center for Bioinformatics and Genome Biology, Centro Ciencia & Vida, Fundación Ciencia & Vida, Santiago, Chile.,Center for Genomics and Bioinformatics, Faculty of Sciences, Universidad Mayor, Santiago, Chile
| | - Eva Vergara
- Center for Bioinformatics and Genome Biology, Centro Ciencia & Vida, Fundación Ciencia & Vida, Santiago, Chile
| | - Mark Dopson
- Centre for Ecology and Evolution in Microbial Model Systems, Linnaeus University, Kalmar, Sweden
| | - Jorge H Valdés
- Center for Bioinformatics and Integrative Biology, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
| | - David S Holmes
- Center for Bioinformatics and Genome Biology, Centro Ciencia & Vida, Fundación Ciencia & Vida, Santiago, Chile.,Facultad de Medicina y Ciencia, Universidad San Sebastián, Santiago, Chile
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8
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Jung H, Inaba Y, Jiang V, West AC, Banta S. Engineering Polyhistidine Tags on Surface Proteins of Acidithiobacillus ferrooxidans: Impact of Localization on the Binding and Recovery of Divalent Metal Cations. ACS APPLIED MATERIALS & INTERFACES 2022; 14:10125-10133. [PMID: 35170950 DOI: 10.1021/acsami.1c23682] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Metal processing using microorganisms has many advantages including the potential for reduced environmental impacts as compared to conventional technologies.Acidithiobacillus ferrooxidansis an iron- and sulfur-oxidizing chemolithoautotroph that is known to participate in metal bioleaching, and its metabolic capabilities have been exploited for industrial-scale copper and gold biomining. In addition to bioleaching, microorganisms could also be engineered for selective metal binding, enabling new opportunities for metal bioseparation and recovery. Here, we explored the ability of polyhistidine (polyHis) tags appended to two recombinantly expressed endogenous proteins to enhance the metal binding capacity of A. ferrooxidans. The genetically engineered cells achieved enhanced cobalt and copper binding capacities, and the Langmuir isotherm captures their interaction behavior with these divalent metals. Additionally, the cellular localization of the recombinant proteins correlated with kinetic modeling of the binding interactions, where the outer membrane-associated polyHis-tagged licanantase peptide bound the metals faster than the periplasmically expressed polyHis-tagged rusticyanin protein. The selectivity of the polyHis sequences for cobalt over copper from mixed metal solutions suggests potential utility in practical applications, and further engineering could be used to create metal-selective bioleaching microorganisms.
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Affiliation(s)
- Heejung Jung
- Department of Chemical Engineering, Columbia University, 500 West 120th Street, New York, New York 10027, United States
| | - Yuta Inaba
- Department of Chemical Engineering, Columbia University, 500 West 120th Street, New York, New York 10027, United States
| | - Virginia Jiang
- Department of Chemical Engineering, Columbia University, 500 West 120th Street, New York, New York 10027, United States
| | - Alan C West
- Department of Chemical Engineering, Columbia University, 500 West 120th Street, New York, New York 10027, United States
| | - Scott Banta
- Department of Chemical Engineering, Columbia University, 500 West 120th Street, New York, New York 10027, United States
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9
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Huang C, Wang C, Luo Y. Research progress of pathway and genome evolution in microbes. Synth Syst Biotechnol 2022; 7:648-656. [PMID: 35224232 PMCID: PMC8857405 DOI: 10.1016/j.synbio.2022.01.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 12/23/2021] [Accepted: 01/06/2022] [Indexed: 12/16/2022] Open
Abstract
Microbes can produce valuable natural products widely applied in medicine, food and other important fields. Nevertheless, it is usually challenging to achieve ideal industrial yields due to low production rate and poor toxicity tolerance. Evolution is a constant mutation and adaptation process used to improve strain performance. Generally speaking, the synthesis of natural products in microbes is often intricate, involving multiple enzymes or multiple pathways. Individual evolution of a certain enzyme often fails to achieve the desired results, and may lead to new rate-limiting nodes that affect the growth of microbes. Therefore, it is inevitable to evolve the biosynthetic pathways or the whole genome. Here, we reviewed the pathway-level evolution including multi-enzyme evolution, regulatory elements engineering, and computer-aided engineering, as well as the genome-level evolution based on several tools, such as genome shuffling and CRISPR/Cas systems. Finally, we also discussed the major challenges faced by in vivo evolution strategies and proposed some potential solutions.
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Affiliation(s)
- Chaoqun Huang
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Chang Wang
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Yunzi Luo
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
- Georgia Tech Shenzhen Institute, Tianjin University, Tangxing Road 133, Nanshan District, Shenzhen, 518071, China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin, 300072, China
- Corresponding author. Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China.
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10
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Jung H, Inaba Y, Banta S. Genetic engineering of the acidophilic chemolithoautotroph Acidithiobacillus ferrooxidans. Trends Biotechnol 2021; 40:677-692. [PMID: 34794837 DOI: 10.1016/j.tibtech.2021.10.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 10/05/2021] [Accepted: 10/06/2021] [Indexed: 12/21/2022]
Abstract
There are several natural and anthropomorphic environments where iron- and/or sulfur-oxidizing bacteria thrive in extremely acidic conditions. These acidophilic chemolithautotrophs play important roles in biogeochemical iron and sulfur cycles, are critical catalysts for industrial metal bioleaching operations, and have underexplored potential in future biotechnological applications. However, their unique growth conditions complicate the development of genetic techniques. Over the past few decades genetic tools have been successfully developed for Acidithiobacillus ferrooxidans, which serves as a model organism that exhibits both iron- and sulfur-oxidizing capabilities. Conjugal transfer of plasmids has enabled gene overexpression, gene knockouts, and some preliminary metabolic engineering. We highlight the development of genetic systems and recent genetic engineering of A. ferrooxidans, and discuss future perspectives.
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Affiliation(s)
- Heejung Jung
- Department of Chemical Engineering, Columbia University, 500 West 120th Street, New York, NY 10027, USA
| | - Yuta Inaba
- Department of Chemical Engineering, Columbia University, 500 West 120th Street, New York, NY 10027, USA
| | - Scott Banta
- Department of Chemical Engineering, Columbia University, 500 West 120th Street, New York, NY 10027, USA.
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11
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Sun Y, Chen W, Wang S, Cao X. Co-occurrence of fosA5, bla SHV-145 and bla OXA-48 among a Klebsiella pneumoniae high-risk ST16 from a tertiary hospital in China: focusing on the phylogeny of OXA-48 genes from global Klebsiella pneumoniae isolates. Braz J Microbiol 2021; 52:2559-2563. [PMID: 34403129 PMCID: PMC8578515 DOI: 10.1007/s42770-021-00572-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 06/29/2021] [Indexed: 11/30/2022] Open
Affiliation(s)
- Yanmei Sun
- Key Laboratory of Resources Biology and Biotechnology in Western China, Ministry of Education, College of Life Science, Northwest University, Xi'an, 710069, People's Republic of China
| | - Wei Chen
- Clinical Research Center, the Second Hospital of Nanjing, Nanjing University of Chinese Medicine, Nanjing, 210003, People's Republic of China
| | - Shiwei Wang
- Key Laboratory of Resources Biology and Biotechnology in Western China, Ministry of Education, College of Life Science, Northwest University, Xi'an, 710069, People's Republic of China.
| | - Xiaoli Cao
- Department of Laboratory Medicine, Nanjing Drum Tower Hospital, the Affiliated Hospital of Nanjing University Medical School, Zhongshan Road, 321#, Gulou District, Nanjing, Jiangsu, People's Republic of China.
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12
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Glutathione synthetase overexpression in Acidithiobacillus ferrooxidans improves halotolerance of iron oxidation. Appl Environ Microbiol 2021; 87:e0151821. [PMID: 34347521 DOI: 10.1128/aem.01518-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Acidithiobacillus ferrooxidans are well-studied iron- and sulfur-oxidizing acidophilic chemolithoautotrophs that are exploited for their ability to participate in the bioleaching of metal sulfides. Here, we overexpressed the endogenous glutamate-cysteine ligase and glutathione synthetase genes in separate strains and found that glutathione synthetase overexpression increased intracellular glutathione levels. We explored the impact of pH on the halotolerance of iron oxidation in wild type and engineered cultures. The increase in glutathione allowed the modified cells to grow under salt concentrations and pH conditions that are fully inhibitory to wild type cells. Furthermore, we found that improved iron oxidation ability in the presence of chloride also resulted in higher levels of intracellular ROS in the strain. These results indicate that glutathione overexpression can be used to increase halotolerance in A. ferrooxidans and would likely be a useful strategy on other acidophilic bacteria. Importance The use of acidophilic bacteria in the hydrometallurgical processing of sulfide ores can enable many benefits including the potential reduction of environmental impacts. The cells involved in bioleaching tend to have limited halotolerance, and increased halotolerance could enable several benefits, including a reduction in the need for the use of fresh water resources. We show that the genetic modification of A. ferrooxidans for the overproduction of glutathione is a promising strategy to enable cells to resist the oxidative stress that can occur during growth in the presence of salt.
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13
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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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14
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Riley LA, Guss AM. Approaches to genetic tool development for rapid domestication of non-model microorganisms. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:30. [PMID: 33494801 PMCID: PMC7830746 DOI: 10.1186/s13068-020-01872-z] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 12/30/2020] [Indexed: 05/04/2023]
Abstract
Non-model microorganisms often possess complex phenotypes that could be important for the future of biofuel and chemical production. They have received significant interest the last several years, but advancement is still slow due to the lack of a robust genetic toolbox in most organisms. Typically, "domestication" of a new non-model microorganism has been done on an ad hoc basis, and historically, it can take years to develop transformation and basic genetic tools. Here, we review the barriers and solutions to rapid development of genetic transformation tools in new hosts, with a major focus on Restriction-Modification systems, which are a well-known and significant barrier to efficient transformation. We further explore the tools and approaches used for efficient gene deletion, DNA insertion, and heterologous gene expression. Finally, more advanced and high-throughput tools are now being developed in diverse non-model microbes, paving the way for rapid and multiplexed genome engineering for biotechnology.
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Affiliation(s)
- Lauren A Riley
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
- Bredesen Center, University of Tennessee, Knoxville, TN, 37996, USA
| | - Adam M Guss
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
- Bredesen Center, University of Tennessee, Knoxville, TN, 37996, USA.
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Gao XY, Fu CA, Hao L, Gu XF, Wang R, Lin JQ, Liu XM, Pang X, Zhang CJ, Lin JQ, Chen LX. The substrate-dependent regulatory effects of the AfeI/R system in Acidithiobacillus ferrooxidans reveals the novel regulation strategy of quorum sensing in acidophiles. Environ Microbiol 2020; 23:757-773. [PMID: 32656931 PMCID: PMC7984328 DOI: 10.1111/1462-2920.15163] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 07/05/2020] [Indexed: 12/22/2022]
Abstract
A LuxI/R‐like quorum sensing (QS) system (AfeI/R) has been reported in the acidophilic and chemoautotrophic Acidithiobacillus spp. However, the function of AfeI/R remains unclear because of the difficulties in the genetic manipulation of these bacteria. Here, we constructed different afeI mutants of the sulfur‐ and iron‐oxidizer A. ferrooxidans, identified the N‐acyl homoserine lactones (acyl‐HSLs) synthesized by AfeI, and determined the regulatory effects of AfeI/R on genes expression, extracellular polymeric substance synthesis, energy metabolism, cell growth and population density of A. ferrooxidans in different energy substrates. Acyl‐HSLs‐mediated distinct regulation strategies were employed to influence bacterial metabolism and cell growth of A. ferrooxidans cultivated in either sulfur or ferrous iron. Based on these findings, an energy‐substrate‐dependent regulation mode of AfeI/R in A. ferrooxidans was illuminated that AfeI/R could produce different types of acyl‐HSLs and employ specific acyl‐HSLs to regulate specific genes in response to different energy substrates. The discovery of the AfeI/R‐mediated substrate‐dependent regulatory mode expands our knowledge on the function of QS system in the chemoautotrophic sulfur‐ and ferrous iron‐oxidizing bacteria, and provides new insights in understanding energy metabolism modulation, population control, bacteria‐driven bioleaching process, and the coevolution between the acidophiles and their acidic habitats.
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Affiliation(s)
- Xue-Yan Gao
- State Key Laboratory of Microbial Technology, Shandong University, No. 72 Binhai Road, Qingdao, 266237, China
| | - Chang-Ai Fu
- State Key Laboratory of Microbial Technology, Shandong University, No. 72 Binhai Road, Qingdao, 266237, China
| | - Likai Hao
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, No. 99 Lincheng West Road, Guiyang, 550081, China.,CAS Center for Excellence in Quaternary Science and Global Change, Xi'an, 710061, China
| | - Xiu-Feng Gu
- State Key Laboratory of Microbial Technology, Shandong University, No. 72 Binhai Road, Qingdao, 266237, China
| | - Rui Wang
- State Key Laboratory of Microbial Technology, Shandong University, No. 72 Binhai Road, Qingdao, 266237, China
| | - Jian-Qiang Lin
- State Key Laboratory of Microbial Technology, Shandong University, No. 72 Binhai Road, Qingdao, 266237, China
| | - Xiang-Mei Liu
- State Key Laboratory of Microbial Technology, Shandong University, No. 72 Binhai Road, Qingdao, 266237, China
| | - Xin Pang
- State Key Laboratory of Microbial Technology, Shandong University, No. 72 Binhai Road, Qingdao, 266237, China
| | - Cheng-Jia Zhang
- State Key Laboratory of Microbial Technology, Shandong University, No. 72 Binhai Road, Qingdao, 266237, China
| | - Jian-Qun Lin
- State Key Laboratory of Microbial Technology, Shandong University, No. 72 Binhai Road, Qingdao, 266237, China
| | - Lin-Xu Chen
- State Key Laboratory of Microbial Technology, Shandong University, No. 72 Binhai Road, Qingdao, 266237, China
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16
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Inaba Y, West AC, Banta S. Enhanced microbial corrosion of stainless steel by
Acidithiobacillus ferrooxidans
through the manipulation of substrate oxidation and overexpression of
rus. Biotechnol Bioeng 2020; 117:3475-3485. [DOI: 10.1002/bit.27509] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 06/24/2020] [Accepted: 07/10/2020] [Indexed: 12/14/2022]
Affiliation(s)
- Yuta Inaba
- Department of Chemical Engineering Columbia University New York New York
| | - Alan C. West
- Department of Chemical Engineering Columbia University New York New York
| | - Scott Banta
- Department of Chemical Engineering Columbia University New York New York
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17
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Novel Strategy for Improvement of the Bioleaching Efficiency of Acidithiobacillus ferrooxidans Based on the AfeI/R Quorum Sensing System. MINERALS 2020. [DOI: 10.3390/min10030222] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Acidithiobacillus ferrooxidans is an acidophilic and chemolithotrophic sulfur- and iron-oxidizing bacterium that has been widely used in the bioleaching process for extracting metals. Extracellular polymeric substances (EPS) are essential for bacteria-ore interactions, and the regulation of EPS synthesis could be an important way of influencing the efficiency of the bioleaching process. Therefore, exploring and utilizing the regulatory pathways of EPS synthesis to improve the bacterial bioleaching capability have posed a challenge in the study and application of bioleaching bacteria. Here, several engineering strains were constructed using genetic manipulation methods. And we revealed the regulatory function of the AfeI/R quorum sensing (QS) system in EPS synthesis and biofilm formation of A. ferrooxidans, and the AfeI/R-mediated EPS synthesis could influence bacteria-substrate interactions and the efficiency of bioleaching. Finally, an AfeI/R-mediated bioleaching model was proposed to illustrate the role of QS system in this process. This study provided new insights into and clues for developing highly efficient bioleaching bacteria and modulating the bioleaching process.
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18
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Stress-tolerant non-conventional microbes enable next-generation chemical biosynthesis. Nat Chem Biol 2020; 16:113-121. [DOI: 10.1038/s41589-019-0452-x] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 12/11/2019] [Indexed: 12/13/2022]
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19
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Microbially Influenced Corrosion of Stainless Steel by Acidithiobacillus ferrooxidans Supplemented with Pyrite: Importance of Thiosulfate. Appl Environ Microbiol 2019; 85:AEM.01381-19. [PMID: 31444204 DOI: 10.1128/aem.01381-19] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 08/19/2019] [Indexed: 11/20/2022] Open
Abstract
Microbially influenced corrosion (MIC) results in significant damage to metallic materials in many industries. Anaerobic sulfate-reducing bacteria (SRB) have been well studied for their involvement in these processes. Highly corrosive environments are also found in pulp and paper processing, where chloride and thiosulfate lead to the corrosion of stainless steels. Acidithiobacillus ferrooxidans is a critically important chemolithotrophic acidophile exploited in metal biomining operations, and there is interest in using A. ferrooxidans cells for emerging processes such as electronic waste recycling. We explored conditions under which A. ferrooxidans could enable the corrosion of stainless steel. Acidic medium with iron, chloride, low sulfate, and pyrite supplementation created an environment where unstable thiosulfate was continuously generated. When combined with the chloride, acid, and iron, the thiosulfate enabled substantial corrosion of stainless steel (SS304) coupons (mass loss, 5.4 ± 1.1 mg/cm2 over 13 days), which is an order of magnitude higher than what has been reported for SRB. There results were verified in an abiotic flow reactor, and the importance of mixing was also demonstrated. Overall, these results indicate that A. ferrooxidans and related pyrite-oxidizing bacteria could produce aggressive MIC conditions in certain environmental milieus.IMPORTANCE MIC of industrial equipment, gas pipelines, and military material leads to billions of dollars in damage annually. Thus, there is a clear need to better understand MIC processes and chemistries as efforts are made to ameliorate these effects. Additionally, A. ferrooxidans is a valuable acidophile with high metal tolerance which can continuously generate ferric iron, making it critical to copper and other biomining operations as well as a potential biocatalyst for electronic waste recycling. New MIC mechanisms may expand the utility of these cells in future metal resource recovery operations.
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20
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Osorio H, Mettert E, Kiley P, Dopson M, Jedlicki E, Holmes DS. Identification and Unusual Properties of the Master Regulator FNR in the Extreme Acidophile Acidithiobacillus ferrooxidans. Front Microbiol 2019; 10:1642. [PMID: 31379789 PMCID: PMC6659574 DOI: 10.3389/fmicb.2019.01642] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 07/02/2019] [Indexed: 12/28/2022] Open
Abstract
The ability to conserve energy in the presence or absence of oxygen provides a metabolic versatility that confers an advantage in natural ecosystems. The switch between alternative electron transport systems is controlled by the fumarate nitrate reduction transcription factor (FNR) that senses oxygen via an oxygen-sensitive [4Fe-4S]2+ iron-sulfur cluster. Under O2 limiting conditions, FNR plays a key role in allowing bacteria to transition from aerobic to anaerobic lifestyles. This is thought to occur via transcriptional activation of genes involved in anaerobic respiratory pathways and by repression of genes involved in aerobic energy production. The Proteobacterium Acidithiobacillus ferrooxidans is a model species for extremely acidophilic microorganisms that are capable of aerobic and anaerobic growth on elemental sulfur coupled to oxygen and ferric iron reduction, respectively. In this study, an FNR-like protein (FNRAF) was discovered in At. ferrooxidans that exhibits a primary amino acid sequence and major motifs and domains characteristic of the FNR family of proteins, including an effector binding domain with at least three of the four cysteines known to coordinate an [4Fe-4S]2+ center, a dimerization domain, and a DNA binding domain. Western blotting with antibodies against Escherichia coli FNR (FNREC) recognized FNRAF. FNRAF was able to drive expression from the FNR-responsive E. coli promoter PnarG, suggesting that it is functionally active as an FNR-like protein. Upon air exposure, FNRAF demonstrated an unusual lack of sensitivity to oxygen compared to the archetypal FNREC. Comparison of the primary amino acid sequence of FNRAF with that of other natural and mutated FNRs, including FNREC, coupled with an analysis of the predicted tertiary structure of FNRAF using the crystal structure of the related FNR from Aliivibrio fisheri as a template revealed a number of amino acid changes that could potentially stabilize FNRAF in the presence of oxygen. These include a truncated N terminus and amino acid changes both around the putative Fe-S cluster coordinating cysteines and also in the dimer interface. Increased O2 stability could allow At. ferrooxidans to survive in environments with fluctuating O2 concentrations, providing an evolutionary advantage in natural, and engineered environments where oxygen gradients shape the bacterial community.
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Affiliation(s)
- Héctor Osorio
- Center for Bioinformatics and Genome Biology, Fundación Ciencia y Vida, Santiago, Chile
| | - Erin Mettert
- Department of Biomolecular Chemistry, University of Wisconsin–Madison, Madison, WI, United States
| | - Patricia Kiley
- Department of Biomolecular Chemistry, University of Wisconsin–Madison, Madison, WI, United States
| | - Mark Dopson
- Centre for Ecology and Evolution in Microbial Model Systems, Linnaeus University, Kalmar, Sweden
| | - Eugenia Jedlicki
- Center for Bioinformatics and Genome Biology, Fundación Ciencia y Vida, Santiago, Chile
| | - David S. Holmes
- Center for Bioinformatics and Genome Biology, Fundación Ciencia y Vida, Santiago, Chile
- Universidad San Sebastian, Santiago, Chile
- Centro de Genómica y Bioinformática, Facultad de Ciencias, Universidad Mayor, Santiago, Chile
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