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Prieto-Fernández F, Lambert S, Kujala K. Assessment of microbial communities from cold mine environments and subsequent enrichment, isolation and characterization of putative antimony- or copper-metabolizing microorganisms. Front Microbiol 2024; 15:1386120. [PMID: 38855773 PMCID: PMC11160943 DOI: 10.3389/fmicb.2024.1386120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Accepted: 04/23/2024] [Indexed: 06/11/2024] Open
Abstract
Mining activities, even in arctic regions, create waste materials releasing metals and metalloids, which have an impact on the microorganisms inhabiting their surroundings. Some species can persist in these areas through tolerance to meta(loid)s via, e.g., metabolic transformations. Due to the interaction between microorganisms and meta(loid)s, interest in the investigation of microbial communities and their possible applications (like bioremediation or biomining) has increased. The main goal of the present study was to identify, isolate, and characterize microorganisms, from subarctic mine sites, tolerant to the metalloid antimony (Sb) and the metal copper (Cu). During both summer and winter, samples were collected from Finnish mine sites (site A and B, tailings, and site C, a water-treatment peatland) and environmental parameters were assessed. Microorganisms tolerant to Sb and Cu were successfully enriched under low temperatures (4°C), creating conditions that promoted the growth of aerobic and fermenting metal(loid) tolerating or anaerobic metal(loid) respiring organism. Microbial communities from the environment and Sb/Cu-enriched microorganisms were studied via 16S rRNA amplicon sequencing. Site C had the highest number of taxa and for all sites, an expected loss of biodiversity occurred when enriching the samples, with genera like Prauserella, Pseudomonas or Clostridium increasing their relative abundances and others like Corynebacterium or Kocuria reducing in relative abundance. From enrichments, 65 putative Sb- and Cu-metabolizing microorganisms were isolated, showing growth at 0.1 mM to 10 mM concentrations and 0°C to 40°C temperatures. 16S rRNA gene sequencing of the isolates indicated that most of the putative anaerobically Sb-respiring tolerators were related to the genus Clostridium. This study represents the first isolation, to our knowledge, of putative Sb-metabolizing cold-tolerant microorganisms and contributes to the understanding of metal (loid)-tolerant microbial communities in Arctic mine sites.
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Compagnone M, González-Cortés JJ, Yeste MDP, Cantero D, Ramírez M. Bioleaching of the α-alumina layer of spent three-way catalysts as a pretreatment for the recovery of platinum group metals. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 345:118825. [PMID: 37634402 DOI: 10.1016/j.jenvman.2023.118825] [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: 01/20/2023] [Revised: 08/08/2023] [Accepted: 08/12/2023] [Indexed: 08/29/2023]
Abstract
Acid bioleaching of Al by Acidithiobacillus thiooxidans has been explored as an environmentally friendly pretreatment to facilitate the extraction of platinum group metals from spent three-way catalysts (TWC). Biogenic sulfur obtained from desulfurization bioreactors improved the production of acid by A. thiooxidans compared to commercially available elemental sulfur. The lixiviation abilities of bacteria-free biogenic acid and biogenic acid with exponential or stationary phase bacteria were compared against a control batch produced by commercial H2SO4. The maximum Al leaching percentage (54.5%) was achieved using biogenic acids with stationary-phase bacteria at a TWC pulp density of 5% w/v whereas bacteria-free biogenic acid (23.4%), biogenic acid with exponential phase bacteria (21.7%) and commercial H2SO4 (24.7%) showed lower leaching abilities. The effect of different pulp densities of ground TWC (5, 30, and 60% w/v) on Al leaching and bacterial growth was determined. While greater Al leaching yields were obtained at lower TWC pulp density solutions (54.5% at 5% w/v and 2.5% at 60% w/v), higher pulp densities enhanced microbial growth (2.3 × 109 cells/mL at 5% w/v and 9.5 × 1010 cells/mL at 60% w/v). The dissolution of the metal from the solid into the liquid phase triggered the production of biological polymeric substances that were able to absorb traces of both Al (up to 24.80% at 5% w/v) and Pt (up to 0.40% at 60% w/v).
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Affiliation(s)
- Mariacristina Compagnone
- Department of Chemical Engineering and Food Technologies, Wine and Agrifood Research Institute (IVAGRO), Faculty of Sciences, University of Cadiz, Cadiz, Spain
| | - José Joaquín González-Cortés
- Department of Chemical Engineering and Food Technologies, Wine and Agrifood Research Institute (IVAGRO), Faculty of Sciences, University of Cadiz, Cadiz, Spain.
| | - María Del Pilar Yeste
- Department of Material Science, Metallurgical Engineering and Inorganic Chemistry, Institute of Research on Electron Microscopy and Materials (IMEYMAT), Faculty of Sciences, University of Cadiz, Spain
| | - Domingo Cantero
- Department of Chemical Engineering and Food Technologies, Wine and Agrifood Research Institute (IVAGRO), Faculty of Sciences, University of Cadiz, Cadiz, Spain
| | - Martín Ramírez
- Department of Chemical Engineering and Food Technologies, Wine and Agrifood Research Institute (IVAGRO), Faculty of Sciences, University of Cadiz, Cadiz, Spain
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Yin Y, Tong Y, Yang H, Feng S. EpsR Ac is a copper-sensing MarR family transcriptional repressor from Acidithiobacillus caldus. Appl Microbiol Biotechnol 2022; 106:3679-3689. [PMID: 35583698 DOI: 10.1007/s00253-022-11971-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 04/25/2022] [Accepted: 05/07/2022] [Indexed: 11/26/2022]
Abstract
The MarR family, as multiple antibiotic resistance regulators, is associated with the resistance of organisms to unfavorable conditions. MarR family extracellular polymeric substances (EPS)-associated transcriptional regulator (EpsRAc) was closely associated with copper resistance in Acidithiobacillus caldus (A. caldus). Transcriptional analysis showed high activity of the epsR promoter (PI) in Escherichia coli and differential response to metal ions. The copper content and UV absorption spectrum of the co-purified protein did not increase, but a stoichiometry of 0.667 mol Cu(I) per EpsRAc monomer was observed in vitro in copper titration experiments, suggesting that Cu(II) acts with low affinity in binding to the EpsRAc protein. Electrophoretic mobility shift assays (EMSA) demonstrated that EpsRAc could bind to its own promoter in vitro, and the binding region was the palindrome sequence TGTTCATCGTGTGTGAGCACACA. EpsRAc negatively regulated its own gene expression, whereas Cu(II) mitigates this negative effect. EpsRAc did not bind to other neighboring gene promoters. Finally, we developed a working model to illustrate the regulatory mechanism of A. caldus in response to extreme copper stress. KEY POINTS: • Identification of a MarR family EPS-associated transcriptional regulator, named EpsRAc. • Cu(I) can bind to the EpsRAc protein with low affinity. • EpsRAc negatively regulates the expression of epsR, and Cu(II) can alleviate this negative regulation.
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Affiliation(s)
- Yijun Yin
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, People's Republic of China
| | - Yanjun Tong
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, People's Republic of China
- School of Food Science and Technology, Jiangnan University, 1800 Lihu Road, Wuxi, People's Republic of China
| | - Hailin Yang
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, People's Republic of China
- Key Laboratory of Carbohydrate Chemistry and Biotechnology (Jiangnan University, Ministry of Education, Jiangnan University, 1800 Lihu Road, Wuxi, People's Republic of China
| | - Shoushuai Feng
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, People's Republic of China.
- Key Laboratory of Carbohydrate Chemistry and Biotechnology (Jiangnan University, Ministry of Education, Jiangnan University, 1800 Lihu Road, Wuxi, People's Republic of China.
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Optimization Studies on Biological Desulfurization of Sulfide Ore Using Response Surface Methodology. MINERALS 2021. [DOI: 10.3390/min11060583] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This research aimed to optimize the experimental conditions of biodesulfurization of sulfide ore and to evaluate the flame-retardant effect after desulfurization under optimal conditions. Six experimental factors were determined: particle size of ore sample, ambient temperature, rotary speed of the shaking table, volume of bacteria liquid, concentration of leaching aid (Tween80), and pH value of acidizing ore sample. Desulfurization efficiency was used as the main characterization index of the desulfurization effect in optimization studies. Particle size of ore sample, rotary speed of the shaking table, and volume of bacteria liquid inoculated were selected as significant factors by a Plackett–Burman experiment. Modeling, optimization, and analysis of the interactive effects of these factors, notably between particle size and bacteria liquid, were performed using a Box–Behnken design with response surface methodology. The optimum operating conditions were found to be: particle size of 120 to 140 mesh, rotary speed of 175 rpm, and bacteria liquid of 111 mL. Under these conditions, a significant rise of 8.1% was seen in 5-day average desulfurization efficiency. The 5-day oxidation weight gain rate of desulfurized ore was 2.73%, while that of the control group was 4.78%. The results show that, after optimized desulfurization, the surface oxidizability and spontaneous combustion tendency of the ore are reduced.
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Feng S, Yin Y, Yin Z, Zhang H, Zhu D, Tong Y, Yang H. Simultaneously enhance iron/sulfur metabolism in column bioleaching of chalcocite by pyrite and sulfur oxidizers based on joint utilization of waste resource. ENVIRONMENTAL RESEARCH 2021; 194:110702. [PMID: 33400950 DOI: 10.1016/j.envres.2020.110702] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 12/21/2020] [Accepted: 12/29/2020] [Indexed: 06/12/2023]
Abstract
In chalcocite (Cu2S) bioleaching, the lack of iron metabolism is a key restricting factor. As the most common sulfide mineral, pyrite (FeS2) can release Fe(Ⅱ) and compensate for the iron metabolism deficiency in chalcocite bioleaching. The bioleaching of chalcocite in an imitated industrial system was improved by enhancing the iron-sulfur metabolism simultaneously using pyrite and sulfur oxidizers based on the joint utilization of waste resources, while the bioleaching performance and community structure in the leachate were systematically investigated. Due to the active sulfur/iron metabolism, the pH reached 1.2, and Fe3+ was increased by 77.78%, while the biomass of planktonic cells was improved to 2.19 × 107 cells/mL. Fourier transform infrared reflection (FTIR) and X-ray diffraction (XRD) analysis results showed that more iron-sulfur crystals were produced due to more active iron-sulfur metabolism. Scanning electron microscopy (SEM) revealed that many derivative particles and corrosion marks appeared on the surface of the ore, implying that the mineral-microbe interaction was strengthened. Confocal laser scanning microscopy (CLSM) showed the accumulation of cells and extracellular polymeric substances (EPS) on the ore surface, indicating a stronger contact leaching mechanism. Furthermore, the community structure and canonical correspondence analysis (CCA) demonstrated that the introduction of sulfur-oxidizing bacteria and pyrite could maintain the diversity of dominant leaching microorganisms at a high level. Sulfobacillus (27.75%) and Leptospirllillum (20.26%) were the dominant sulfur-oxidizing and iron-oxidizing bacteria during the bioleaching process. With the accumulation of multiple positive effects, the copper ion leaching rate was improved by 44.8%. In general, this new type of multiple intervention strategy can provide an important guide for the bioleaching of low-grade ores.
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Affiliation(s)
- Shoushuai Feng
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Yijun Yin
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Zongwei Yin
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Hailing Zhang
- Department of Biological Engineering, College of Life Science, Yantai University, Shandong, 408100, China
| | - Deqiang Zhu
- State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan, 250353, China.
| | - Yanjun Tong
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Hailin Yang
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China; Key Laboratory of Carbohydrate Chemistry and Biotechnology (Jiangnan University) Ministry of Education, China.
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