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Sun L, Sheng Q, Ge Y, He L, Sheng X. The quorum sensing SinI/R system contributes to cadmium immobilization in Ensifer adhaerens NER9 in the cadmium-contaminated solution. JOURNAL OF HAZARDOUS MATERIALS 2024; 470:134300. [PMID: 38631248 DOI: 10.1016/j.jhazmat.2024.134300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 03/19/2024] [Accepted: 04/11/2024] [Indexed: 04/19/2024]
Abstract
In this study, the cadmium (Cd)-tolerant Ensifer adhaerens strain NER9 with quorum sensing (QS) systems (responsible for N-acyl homoserine lactone (AHL) production) was characterized for QS system-mediated Cd immobilization and the underlying mechanisms involved. Whole-genome sequence analysis revealed that strain NER9 contains the QS SinI/R and TraI/R systems. Strains NER9 and the NER9∆sinI/R, NER9∆traI/R, and NER9∆sinI/R-traI/R mutants were constructed and compared for QS SinI/R and TraI/R system-mediated Cd immobilization in the solution and the mechanisms involved. After 24 h of incubation, strain NER9 significantly decreased the Cd concentration in the Cd-contaminated solution compared with the NER9∆sinI/R, NER9∆traI/R, and NER9∆sinI/R-traI/R mutants. The NER9∆sinI/R mutant had a greater impact on Cd immobilization and a lower impact on the activities of AHLs than did the NER9∆traI/R mutant. The NER9∆sinI/R mutant had significantly greater Cd concentrations and lower cell wall- and exopolysaccharide (EPS)-adsorbed Cd contents than did strain NER9. Furthermore, the NER9∆sinI/R mutant presented a decrease in the number of functional groups interacting with Cd, compared with strain NER9. These results suggested that the SinI/R system in strain NER9 contributed to Cd immobilization by mediating cell wall- and EPS-adsorption in Cd-containing solution.
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Affiliation(s)
- Lijing Sun
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Qi Sheng
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Yanyan Ge
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Linyan He
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Xiafang Sheng
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China.
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2
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Radojević ID, Jakovljević VD, Ostojić AM. A mini-review on indigenous microbial biofilm from various wastewater for heavy-metal removal - new trends. World J Microbiol Biotechnol 2023; 39:309. [PMID: 37715865 DOI: 10.1007/s11274-023-03762-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 09/12/2023] [Indexed: 09/18/2023]
Abstract
Biofilm, as a form of the microbial community in nature, represents an evolutionary adaptation to the influence of various environmental conditions. In nature, the largest number of microorganisms occur in the form of multispecies biofilms. The ability of microorganisms to form a biofilm is one of the reasons for antibiotic resistance. The creation of biofilms resistant to various contaminants, on the other hand, improves the biological treatment process in wastewater treatment plants. Heavy metals cannot be degraded, but they can be transformed into non-reactive and less toxic forms. In this process, microorganisms are irreplaceable as they interact with the metals in a variety of ways. The environment polluted by heavy metals, such as wastewater, is also a source of undiscovered microbial diversity and specific microbial strains. Numerous studies show that biofilm is an irreplaceable strategy for heavy metal removal. In this review, we systematize recent findings regarding the bioremediation potential of biofilm-forming microbial species isolated from diverse wastewaters for heavy metal removal. In addition, we include some mechanisms of action, application possibilities, practical issues, and future prospects.
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Affiliation(s)
- Ivana D Radojević
- Faculty of Science, Department of Biology and Ecology, Laboratory of microbiology, University of Kragujevac, Radoja Domanoviča 12, 34000, Kragujevac, Republic of Serbia.
| | - Violeta D Jakovljević
- Department of Natural-Mathematical Sciences, State University of Novi Pazar, Vuka Karadžića 9, 36300, Novi Pazar, Republic of Serbia
| | - Aleksandar M Ostojić
- Faculty of Science, Department of Biology and Ecology, Laboratory of microbiology, University of Kragujevac, Radoja Domanoviča 12, 34000, Kragujevac, Republic of Serbia
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Chidiac C, Kim Y, de Lannoy C. Enhanced Pb(II) removal from water using conductive carbonaceous nanomaterials as bacterial scaffolds: An experimental and modelling approach. JOURNAL OF HAZARDOUS MATERIALS 2022; 431:128516. [PMID: 35255332 DOI: 10.1016/j.jhazmat.2022.128516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 02/14/2022] [Accepted: 02/17/2022] [Indexed: 06/14/2023]
Abstract
This study investigated the abilities of electrochemically active bacteria (EAB) as bio-catalysts for Pb(II) bioreduction in an attached growth reactor. Electrically conductive carbon nanofibers (CNF) were used as bacterial scaffolds to facilitate electron transfer between EAB and Pb(II). Our results demonstrated that the CNF attached growth reactor can remove > 80% and > 90% of Pb(II) from solution at 0.5 mg/L and 5.0 mg/L concentrations, respectively, and maintained Pb(II) levels < 0.10 mg/L over repeated Pb(II) dosages dosed at all concentrations. Experimental measurements by SEM-EDX and ICP-OES provided evidence that Pb(II) was reduced to Pb0, suggesting that Pb(II) was adsorbed onto CNFs, and subsequently bioreduced. Numerical modelling was used to estimate Pb(II) concentrations along the CNFs via capturing Pb(II)'s diffusive transport, and the removal mechanisms governed by EAB and CNF adsorption. The model simulation results demonstrated that Pb(II) bioreduction was dominant in the reactor and the significance of Monod kinetics, biofilm thickness and Pb(II) dosage concentration on its removal. This study is the first to prove EAB's ability to treat Pb(II) from contaminated waters in an attached growth configuration. The findings here demonstrate that CNFs can boost biological treatment efficacies in wastewater and/or water treatment to meet stringent water guidelines.
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Affiliation(s)
- Cassandra Chidiac
- Department of Chemical Engineering, McMaster University, 1280 Main Street West, Hamilton, ON, Canada.
| | - Younggy Kim
- Department of Civil Engineering, McMaster University, Canada.
| | - Charles de Lannoy
- Department of Chemical Engineering, McMaster University, 1280 Main Street West, Hamilton, ON, Canada.
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Bacterial Biosorbents, an Efficient Heavy Metals Green Clean-Up Strategy: Prospects, Challenges, and Opportunities. Microorganisms 2022; 10:microorganisms10030610. [PMID: 35336185 PMCID: PMC8953973 DOI: 10.3390/microorganisms10030610] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 03/09/2022] [Accepted: 03/10/2022] [Indexed: 12/17/2022] Open
Abstract
Rapid industrialization has led to the pollution of soil and water by various types of contaminants. Heavy metals (HMs) are considered the most reactive toxic contaminants, even at low concentrations, which cause health problems through accumulation in the food chain and water. Remediation using conventional methods, including physical and chemical techniques, is a costly treatment process and generates toxic by-products, which may negatively affect the surrounding environment. Therefore, biosorption has attracted significant research interest in the recent decades. In contrast to existing methods, bacterial biomass offers a potential alternative for recovering toxic/persistent HMs from the environment through different mechanisms for metal ion uptake. This review provides an outlook of the advantages and disadvantages of the current bioremediation technologies and describes bacterial groups, especially extremophiles with biosorbent potential for heavy metal removal with relevant examples and perspectives.
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Rosca M, Cozma P, Minut M, Hlihor RM, Bețianu C, Diaconu M, Gavrilescu M. New Evidence of Model Crop Brassica napus L. in Soil Clean-Up: Comparison of Tolerance and Accumulation of Lead and Cadmium. PLANTS 2021; 10:plants10102051. [PMID: 34685860 PMCID: PMC8538861 DOI: 10.3390/plants10102051] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Revised: 09/22/2021] [Accepted: 09/25/2021] [Indexed: 11/17/2022]
Abstract
The potential of the model crop Brassica napus L. (rapeseed) for the phytoremediation of soils polluted with metals was investigated at laboratory scale. The first step consists in the evaluation of the seed germination and growth of the Brassica napus L. plant in a controlled environment, followed by the determination of the photosynthetic pigments content represented by chlorophyll a and b and carotenoids. The degree of metal accumulation in rapeseed has been evaluated by the bioaccumulation factor (BAC), the bioconcentration factor (BCF) and the translocation factor (TF). Phytotoxicity tests were performed in Petri dishes with filter papers moistened with metal solutions in the range of 0 to 300 mg/L Pb(II) or Cd(II). At the highest concentration of the lead and cadmium treatments (300 mg/L), B. napus L. showed the lowest germination degree (56.67% and 43.33%, respectively). According to Tukey test results, Pb(II) concentrations of up to 300 mg/L do not significantly affect the length of the hypocotyls, whereas, in the case of Cd(II), the mean of the radicle and hypocotyl lengths of the seedlings are significantly affected compared to the mean of the control. In soil pot experiments, important changes have been obtained in the pigment content, especially in the case of cadmium. For both metals and for each treatment (100 to 1500 mg/kg Pb(II) and 1 to 30 mg/kg Cd(II)), a TF < 1 indicates an ineffective metal transfer from root to shoot. Finally, rapeseed can be considered a tolerant plant and a suitable candidate for Pb(II) and Cd(II) accumulation and for the phytostabilization of contaminated soil under the experimental conditions adopted in the present study.
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Affiliation(s)
- Mihaela Rosca
- Department of Environmental Engineering and Management, “Cristofor Simionescu” Faculty of Chemical Engineering and Environmental Protection, “Gheorghe Asachi” Technical University of Iasi, 73 Prof. D. Mangeron Blvd., 700050 Iasi, Romania; (M.R.); (M.M.); (R.-M.H.); (C.B.); (M.D.)
- Department of Horticultural Technologies, Faculty of Horticulture, “Ion Ionescu de la Brad” Iasi University of Life Sciences, 3 Mihail Sadoveanu Alley, 700490 Iasi, Romania
| | - Petronela Cozma
- Department of Environmental Engineering and Management, “Cristofor Simionescu” Faculty of Chemical Engineering and Environmental Protection, “Gheorghe Asachi” Technical University of Iasi, 73 Prof. D. Mangeron Blvd., 700050 Iasi, Romania; (M.R.); (M.M.); (R.-M.H.); (C.B.); (M.D.)
- Department of Horticultural Technologies, Faculty of Horticulture, “Ion Ionescu de la Brad” Iasi University of Life Sciences, 3 Mihail Sadoveanu Alley, 700490 Iasi, Romania
- Correspondence: (P.C.); (M.G.)
| | - Mariana Minut
- Department of Environmental Engineering and Management, “Cristofor Simionescu” Faculty of Chemical Engineering and Environmental Protection, “Gheorghe Asachi” Technical University of Iasi, 73 Prof. D. Mangeron Blvd., 700050 Iasi, Romania; (M.R.); (M.M.); (R.-M.H.); (C.B.); (M.D.)
| | - Raluca-Maria Hlihor
- Department of Environmental Engineering and Management, “Cristofor Simionescu” Faculty of Chemical Engineering and Environmental Protection, “Gheorghe Asachi” Technical University of Iasi, 73 Prof. D. Mangeron Blvd., 700050 Iasi, Romania; (M.R.); (M.M.); (R.-M.H.); (C.B.); (M.D.)
- Department of Horticultural Technologies, Faculty of Horticulture, “Ion Ionescu de la Brad” Iasi University of Life Sciences, 3 Mihail Sadoveanu Alley, 700490 Iasi, Romania
| | - Camelia Bețianu
- Department of Environmental Engineering and Management, “Cristofor Simionescu” Faculty of Chemical Engineering and Environmental Protection, “Gheorghe Asachi” Technical University of Iasi, 73 Prof. D. Mangeron Blvd., 700050 Iasi, Romania; (M.R.); (M.M.); (R.-M.H.); (C.B.); (M.D.)
| | - Mariana Diaconu
- Department of Environmental Engineering and Management, “Cristofor Simionescu” Faculty of Chemical Engineering and Environmental Protection, “Gheorghe Asachi” Technical University of Iasi, 73 Prof. D. Mangeron Blvd., 700050 Iasi, Romania; (M.R.); (M.M.); (R.-M.H.); (C.B.); (M.D.)
| | - Maria Gavrilescu
- Department of Environmental Engineering and Management, “Cristofor Simionescu” Faculty of Chemical Engineering and Environmental Protection, “Gheorghe Asachi” Technical University of Iasi, 73 Prof. D. Mangeron Blvd., 700050 Iasi, Romania; (M.R.); (M.M.); (R.-M.H.); (C.B.); (M.D.)
- Academy of Romanian Scientists, 3 Ilfov Street, 050094 Bucharest, Romania
- Correspondence: (P.C.); (M.G.)
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Heidari P, Panico A. Sorption Mechanism and Optimization Study for the Bioremediation of Pb(II) and Cd(II) Contamination by Two Novel Isolated Strains Q3 and Q5 of Bacillus sp. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:E4059. [PMID: 32517236 PMCID: PMC7312031 DOI: 10.3390/ijerph17114059] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 05/26/2020] [Accepted: 06/04/2020] [Indexed: 11/22/2022]
Abstract
The use of bacterial strains as agents in bioremediation processes could reduce the harmfulness of potential toxic elements (PTEs) from water and soil with low or even no impact on the natural ecosystems. In this study, two new metal resistant-bacterial strains (Q3 and Q5) of Bacillus sp. were isolated from a sulfurous spring and their potential (as pure cultures or mixed) to remove Pb(II) and Cd(II) from an aqueous matrix was evaluated and optimized using response surface methodology (RSM). The optimal conditions for Cd(II) removal from all tested strains combinations were observed at an initial pH 5, a temperature of 38 °C, and an initial Cd(II) concentration of 50 mg L-1, while the performance of bacterial strains on Pb(II) removal was strongly correlated to initial pH and temperature conditions. Moreover, the efficiency of bacterial strains in removing both PTEs, Pb(II) and Cd(II), from an aqueous matrix was considerably higher when they were used as a mixed culture rather than pure. According to field emission SEM (FESEM) and EDS analysis, the two bacterial strains showed different mechanisms in removing Cd(II): Bacillus sp. Q5 bio-accumulated Cd(II) in its periplasmic space, whereas Bacillus sp. Q3 bio-accumulated Cd(II) on its cell surface. On the other hand, Pb(II) is removed by chemical precipitation (lead sulfide) induced by both Bacillus sp. Q3 and Q5. This study discloses new aspects of Pb(II) and Cd(II) bioremediation mechanisms in Bacillus species that can be extremely useful for designing and operating novel PTEs bioremediation processes.
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Affiliation(s)
- Parviz Heidari
- Faculty of Agriculture, Shahrood University of Technology, Shahrood 3619995161, Iran
| | - Antonio Panico
- Telematic University Pegaso, Piazza Trieste e Trento 48, 80132 Naples, Italy;
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Hu X, Cao J, Yang H, Li D, Qiao Y, Zhao J, Zhang Z, Huang L. Pb2+ biosorption from aqueous solutions by live and dead biosorbents of the hydrocarbon-degrading strain Rhodococcus sp. HX-2. PLoS One 2020; 15:e0226557. [PMID: 31995615 PMCID: PMC6988972 DOI: 10.1371/journal.pone.0226557] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 11/29/2019] [Indexed: 01/14/2023] Open
Abstract
In this study, the Pb2+ biosorption potential of live and dead biosorbents of the hydrocarbon-degrading strain Rhodococcus sp. HX-2 was analyzed. Optimal biosorption conditions were determined via single factor optimization, which were as follows: temperature, 25°C; pH, 5.0, and biosorbent dose, 0.75 g L−1. A response surface software (Design Expert 10.0) was used to analyze optimal biosorption conditions. The biosorption data for live and dead biosorbents were suitable for the Freundlich model at a Pb2+ concentration of 200 mg L−1. At this same concentration, the maximum biosorption capacity was 88.74 mg g−1 (0.428 mmol g−1) for live biosorbents and 125.5 mg g−1 (0.606 mmol g−1) for dead biosorbents. Moreover, in comparison with the pseudo-first-order model, the pseudo-second-order model seemed better to depict the biosorption process. Dead biosorbents seemed to have lower binding strength than live biosorbents, showing a higher desorption capacity at pH 1.0. The order of influence of competitive metal ions on Pb2+ adsorption was Cu2+ > Cd2+ > Ni+. Fourier-transform infrared spectroscopy analyses revealed that several functional groups were involved in the biosorption process of dead biosorbents. Scanning electron microscopy showed that Pb2+ attached to the surface of dead biosorbents more readily than on the surface of live biosorbents, whereas transmission electron microscopy confirmed the transfer of biosorbed Pb2+ into the cells in the case of both live and dead biosorbents. It can thus be concluded that dead biosorbents are better than live biosorbents for Pb2+ biosorption, and they can accordingly be used for wastewater treatment.
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Affiliation(s)
- Xin Hu
- College of Chemistry and Chemical Engineering, Tianjin Key Laboratory of Drug Targeting and Bioimaging, Tianjin Key Laboratory of Organic Solar Cells and Photochemical Conversion, Tianjin University of Technology, Tianjin, China
| | - Jiachang Cao
- College of Chemistry and Chemical Engineering, Tianjin Key Laboratory of Drug Targeting and Bioimaging, Tianjin Key Laboratory of Organic Solar Cells and Photochemical Conversion, Tianjin University of Technology, Tianjin, China
| | - Hanyu Yang
- College of Management Science and Engineering, Capital University of Economics and Business, Beijing, China
| | - Dahui Li
- College of Chemistry and Chemical Engineering, Tianjin Key Laboratory of Drug Targeting and Bioimaging, Tianjin Key Laboratory of Organic Solar Cells and Photochemical Conversion, Tianjin University of Technology, Tianjin, China
| | - Yue Qiao
- College of Chemistry and Chemical Engineering, Tianjin Key Laboratory of Drug Targeting and Bioimaging, Tianjin Key Laboratory of Organic Solar Cells and Photochemical Conversion, Tianjin University of Technology, Tianjin, China
| | - Jialin Zhao
- College of Chemistry and Chemical Engineering, Tianjin Key Laboratory of Drug Targeting and Bioimaging, Tianjin Key Laboratory of Organic Solar Cells and Photochemical Conversion, Tianjin University of Technology, Tianjin, China
| | - Zhixia Zhang
- College of Chemistry and Chemical Engineering, Tianjin Key Laboratory of Drug Targeting and Bioimaging, Tianjin Key Laboratory of Organic Solar Cells and Photochemical Conversion, Tianjin University of Technology, Tianjin, China
| | - Lei Huang
- College of Chemistry and Chemical Engineering, Tianjin Key Laboratory of Drug Targeting and Bioimaging, Tianjin Key Laboratory of Organic Solar Cells and Photochemical Conversion, Tianjin University of Technology, Tianjin, China
- * E-mail:
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8
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Nong Q, Yuan K, Li Z, Chen P, Huang Y, Hu L, Jiang J, Luan T, Chen B. Bacterial resistance to lead: Chemical basis and environmental relevance. J Environ Sci (China) 2019; 85:46-55. [PMID: 31471030 DOI: 10.1016/j.jes.2019.04.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Accepted: 04/19/2019] [Indexed: 06/10/2023]
Abstract
Natural bacterial isolates from heavily contaminated sites may evolve diverse tolerance strategies, including biosorption, efflux mechanism, and intracellular precipitation under the continually increased stress of toxic lead (Pb) from anthropogenic activities. These strategies utilize a large variety of functional groups in biological macromolecules (e.g., exopolysaccharides (EPSs) and metalloproteins) and inorganic ligands, including carboxyl, phosphate and amide groups, for capturing Pb. The amount and type of binding sites carried by biologically originated materials essentially determines their performance and potential for Pb removal and remediation. Many factors, e.g., metal ion radius, electronegativity, the shape of the cell surface sheath, temperature and pH, are thought to exert significant influences on the abovementioned interactions with Pb. Conclusively, understanding the chemical basis of Pb-binding in these bacteria can allow for the development of effective microbial Pb remediation technologies and further elucidation of Pb cycling in the environment.
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Affiliation(s)
- Qiying Nong
- School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Ke Yuan
- Southern Marine Science and Engineering Guangdong Laboratory, School of Marine Sciences, Sun Yat-Sen University, Zhuhai 519082, China
| | - Zhuang Li
- Southern Marine Science and Engineering Guangdong Laboratory, School of Marine Sciences, Sun Yat-Sen University, Zhuhai 519082, China
| | - Ping Chen
- School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Yongshun Huang
- Guangdong Provincial Hospital for Occupational Diseases Prevention and Treatment, Guangzhou 510300, China
| | - Ligang Hu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P. O. Box 2871, Beijing 100085, China
| | - Jie Jiang
- Shenzhen Center for Disease Control and Prevention, Shenzhen 518055, China
| | - Tiangang Luan
- Southern Marine Science and Engineering Guangdong Laboratory, School of Marine Sciences, Sun Yat-Sen University, Zhuhai 519082, China; School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China; School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Baowei Chen
- Southern Marine Science and Engineering Guangdong Laboratory, School of Marine Sciences, Sun Yat-Sen University, Zhuhai 519082, China.
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Yurgel SN, Nearing JT, Douglas GM, Langille MGI. Metagenomic Functional Shifts to Plant Induced Environmental Changes. Front Microbiol 2019; 10:1682. [PMID: 31404278 PMCID: PMC6676915 DOI: 10.3389/fmicb.2019.01682] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Accepted: 07/08/2019] [Indexed: 11/13/2022] Open
Abstract
The Vaccinium angustifolium (wild blueberry) agricultural system involves transformation of the environment surrounding the plant to intensify plant propagation and to improve fruit yield, and therefore is an advantageous model to study the interaction between soil microorganisms and plant-host interactions. We studied this system to address the question of a trade-off between microbial adaptation to a plant-influenced environment and its general metabolic capabilities. We found that many basic metabolic functions were similarly represented in bulk soil and rhizosphere microbiomes overall. However, we identified a niche-specific difference in functions potentially beneficial for microbial survival in the rhizosphere but that might also reduce the ability of microbes to withstand stresses in bulk soils. These functions could provide the microbiome with additional capabilities to respond to environmental fluctuations in the rhizosphere triggered by changes in the composition of root exudates. Based on our analysis we hypothesize that the rhizosphere-specific pathways involved in xenobiotics biodegradation could provide the microbiome with functional flexibility to respond to plant stress status.
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Affiliation(s)
- Svetlana N Yurgel
- Department of Plant, Food, and Environmental Sciences, Dalhousie University, Halifax, NS, Canada
| | - Jacob T Nearing
- Department of Microbiology and Immunology, Dalhousie University, Halifax, NS, Canada
| | - Gavin M Douglas
- Department of Microbiology and Immunology, Dalhousie University, Halifax, NS, Canada
| | - Morgan G I Langille
- Department of Microbiology and Immunology, Dalhousie University, Halifax, NS, Canada.,Department of Pharmacology, Dalhousie University, Halifax, NS, Canada
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Vimalnath S, Ravishankar H, Schwandt C, Kumar RV, Subramanian S. Mechanistic studies on the biosorption of Pb(II) by Pseudomonas aeruginosa. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2018; 78:290-300. [PMID: 30101764 DOI: 10.2166/wst.2018.296] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The biosorption of Pb(II) ions from aqueous solution has been studied using both the intact and thermolyzed cells of Pseudomonas aeruginosa. Further, the role of the major cell wall components, namely DNA, protein, polysaccharide, and lipid, in Pb(II) binding has been assessed using an enzymatic treatment method. The Pb(II) bioremediation capability of P. aeruginosa cells has been investigated by varying the parameters of pH, time of interaction, amount of biomass, and concentration of Pb(II). The complete bioremoval of Pb(II) using intact cells has been achieved for an initial Pb(II) concentration of 12.4 mg L-1 at pH 6.2 and temperature 29 ± 1 °C. The biosorption isotherm follows Langmuirian behavior with a Gibbs free energy of -30.7 kJ mol-1, indicative of chemisorption. The biosorption kinetics is consistent with a pseudo-second-order model. The possible Pb(II) binding mechanisms of P. aeruginosa cells are discussed based on characterization using zeta potential measurements, Fourier transform infra-red spectroscopy, and energy dispersive X-ray spectroscopy. The results confirm that among the major cell wall components studied, polysaccharide shows the highest contribution towards Pb(II) binding, followed by DNA, lipid, and protein. Similar studies using thermolyzed cells show higher Pb(II) uptake compared to the intact cells both before and after enzymatic treatment.
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Affiliation(s)
- S Vimalnath
- Department of Materials Engineering, Indian Institute of Science, Bangalore 560012, India E-mail:
| | - H Ravishankar
- Department of Materials Engineering, Indian Institute of Science, Bangalore 560012, India E-mail:
| | - C Schwandt
- Department of Materials Science & Metallurgy, University of Cambridge, Cambridge CB3 0FS, UK
| | - R V Kumar
- Department of Materials Science & Metallurgy, University of Cambridge, Cambridge CB3 0FS, UK
| | - S Subramanian
- Department of Materials Engineering, Indian Institute of Science, Bangalore 560012, India E-mail:
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