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Somee MR, Amoozegar MA, Dastgheib SMM, Shavandi M, Maman LG, Bertilsson S, Mehrshad M. Genome-resolved analyses show an extensive diversification in key aerobic hydrocarbon-degrading enzymes across bacteria and archaea. BMC Genomics 2022; 23:690. [PMID: 36203131 PMCID: PMC9535955 DOI: 10.1186/s12864-022-08906-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Accepted: 09/26/2022] [Indexed: 12/04/2022] Open
Abstract
Background Hydrocarbons (HCs) are organic compounds composed solely of carbon and hydrogen that are mainly accumulated in oil reservoirs. As the introduction of all classes of hydrocarbons including crude oil and oil products into the environment has increased significantly, oil pollution has become a global ecological problem. However, our perception of pathways for biotic degradation of major HCs and key enzymes in these bioconversion processes has mainly been based on cultured microbes and is biased by uneven taxonomic representation. Here we used Annotree to provide a gene-centric view of the aerobic degradation ability of aliphatic and aromatic HCs in 23,446 genomes from 123 bacterial and 14 archaeal phyla. Results Apart from the widespread genetic potential for HC degradation in Proteobacteria, Actinobacteriota, Bacteroidota, and Firmicutes, genomes from an additional 18 bacterial and 3 archaeal phyla also hosted key HC degrading enzymes. Among these, such degradation potential has not been previously reported for representatives in the phyla UBA8248, Tectomicrobia, SAR324, and Eremiobacterota. Genomes containing whole pathways for complete degradation of HCs were only detected in Proteobacteria and Actinobacteriota. Except for several members of Crenarchaeota, Halobacterota, and Nanoarchaeota that have tmoA, ladA, and alkB/M key genes, respectively, representatives of archaeal genomes made a small contribution to HC degradation. None of the screened archaeal genomes coded for complete HC degradation pathways studied here; however, they contribute significantly to peripheral routes of HC degradation with bacteria. Conclusion Phylogeny reconstruction showed that the reservoir of key aerobic hydrocarbon-degrading enzymes in Bacteria and Archaea undergoes extensive diversification via gene duplication and horizontal gene transfer. This diversification could potentially enable microbes to rapidly adapt to novel and manufactured HCs that reach the environment. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-022-08906-w.
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Affiliation(s)
- Maryam Rezaei Somee
- Extremophile Laboratory, Department of Microbiology, School of Biology, College of Science, University of Tehran, Tehran, Iran
| | - Mohammad Ali Amoozegar
- Extremophile Laboratory, Department of Microbiology, School of Biology, College of Science, University of Tehran, Tehran, Iran
| | | | - Mahmoud Shavandi
- Biotechnology Research Group, Research Institute of Petroleum Industry, Tehran, Iran
| | - Leila Ghanbari Maman
- Laboratory of Complex Biological Systems and Bioinformatics (CBB), Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran
| | - Stefan Bertilsson
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences (SLU), Box 7050, 75007, Uppsala, Sweden
| | - Maliheh Mehrshad
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences (SLU), Box 7050, 75007, Uppsala, Sweden.
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Bhatt P, Bhandari G, Bhatt K, Maithani D, Mishra S, Gangola S, Bhatt R, Huang Y, Chen S. Plasmid-mediated catabolism for the removal of xenobiotics from the environment. JOURNAL OF HAZARDOUS MATERIALS 2021; 420:126618. [PMID: 34329102 DOI: 10.1016/j.jhazmat.2021.126618] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 05/27/2021] [Accepted: 07/08/2021] [Indexed: 06/13/2023]
Abstract
The large-scale application of xenobiotics adversely affects the environment. The genes that are present in the chromosome of the bacteria are considered nonmobile, whereas the genes present on the plasmids are considered mobile genetic elements. Plasmids are considered indispensable for xenobiotic degradation into the contaminated environment. In the contaminated sites, bacteria with plasmids can transfer the mobile genetic element into another strain. This mechanism helps in spreading the catabolic genes into the bacterial population at the contaminated sites. The indigenous microbial strains with such degradative plasmids are important for the bioremediation of xenobiotics. Environmental factors play a critical role in the conjugation efficiency, which is involved in the bioremediation of the xenobiotics at the contaminated sites. However, there is still a need for more research to fill in the gaps regarding plasmids and their impact on bioremediation. This review explores the role of bacterial plasmids in the bioremediation of xenobiotics from contaminated environments.
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Affiliation(s)
- Pankaj Bhatt
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou 510642, China; Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
| | - Geeta Bhandari
- Department of Biochemistry and Biotechnology, Sardar Bhagwan Singh University, Dehradun 248161, Uttarakhand, India
| | - Kalpana Bhatt
- Department of Botany and Microbiology, Gurukul Kangri University, Haridwar 249404, Uttarakhand, India
| | - Damini Maithani
- Department of Microbiology, G.B Pant University of Agriculture and Technology Pantnagar, U.S Nagar, Uttarakhand, India
| | - Sandhya Mishra
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou 510642, China; Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
| | - Saurabh Gangola
- School of Agriculture, Graphic Era Hill University, Bhimtal Campus, 263136, Uttarakhand, India
| | - Rakesh Bhatt
- Department of Civil Engineering, Indian Institute of Technology, Kanpur 208016, Uttar Pradesh, India
| | - Yaohua Huang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou 510642, China; Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
| | - Shaohua Chen
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou 510642, China; Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China.
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Wang GH, Tsai TH, Kui CC, Cheng CY, Huang TL, Chung YC. Analysis of bioavailable toluene by using recombinant luminescent bacterial biosensors with different promoters. J Biol Eng 2021; 15:2. [PMID: 33407661 PMCID: PMC7789755 DOI: 10.1186/s13036-020-00254-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Accepted: 12/29/2020] [Indexed: 01/24/2023] Open
Abstract
In this study, we constructed recombinant luminescent Escherichia coli with T7, T3, and SP6 promoters inserted between tol and lux genes as toluene biosensors and evaluated their sensitivity, selectivity, and specificity for measuring bioavailable toluene in groundwater and river water. The luminescence intensity of each biosensor depended on temperature, incubation time, ionic strength, and concentrations of toluene and coexisting organic compounds. Toluene induced the highest luminescence intensity in recombinant lux-expressing E. coli with the T7 promoter [T7-lux-E. coli, limit of detection (LOD) = 0.05 μM], followed by that in E. coli with the T3 promoter (T3-lux-E. coli, LOD = 0.2 μM) and SP6 promoter (SP6-lux-E. coli, LOD = 0.5 μM). Luminescence may have been synergistically or antagonistically affected by coexisting organic compounds other than toluene; nevertheless, low concentrations of benzoate and toluene analogs had no such effect. In reproducibility experiments, the biosensors had low relative standard deviation (4.3-5.8%). SP6-lux-E. coli demonstrated high adaptability to environmental interference. T7-lux-E. coli biosensor-with low LOD, wide measurement range (0.05-500 μM), and acceptable deviation (- 14.3 to 9.1%)-is an efficient toluene biosensor. This is the first study evaluating recombinant lux E. coli with different promoters for their potential application in toluene measurement in actual water bodies.
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Affiliation(s)
- Guey-Horng Wang
- Research Center of Natural Cosmeceuticals Engineering, Xiamen Medical College, Xiamen, 361008, China
| | - Teh-Hua Tsai
- Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, Taipei, Taiwan
| | - Chun-Chi Kui
- Department of Biological Science and Technology, China University of Science and Technology, Taipei, 11581, Taiwan
| | - Chiu-Yu Cheng
- Department of Biological Science and Technology, China University of Science and Technology, Taipei, 11581, Taiwan
| | - Tzu-Ling Huang
- Department of Biological Science and Technology, China University of Science and Technology, Taipei, 11581, Taiwan
| | - Ying-Chien Chung
- Department of Biological Science and Technology, China University of Science and Technology, Taipei, 11581, Taiwan.
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Sysoeva TA, Kim Y, Rodriguez J, Lopatkin AJ, You L. Growth‐stage‐dependent regulation of conjugation. AIChE J 2019. [DOI: 10.1002/aic.16848] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Tatyana A. Sysoeva
- Department of Biomedical EngineeringDuke University Durham North Carolina
- Department of Biological SciencesThe University of Alabama in Huntsville Huntsville Alabama
| | - Youlim Kim
- Department of Biomedical EngineeringDuke University Durham North Carolina
| | - Jonathan Rodriguez
- Department of Biomedical EngineeringDuke University Durham North Carolina
| | | | - Lingchong You
- Department of Biomedical EngineeringDuke University Durham North Carolina
- Center for Genomic and Computational BiologyDuke University Durham North Carolina
- Department of Molecular Genetics and MicrobiologyDuke University School of Medicine North Carolina
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5
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Redfern LK, Gardner CM, Hodzic E, Ferguson PL, Hsu-Kim H, Gunsch CK. A new framework for approaching precision bioremediation of PAH contaminated soils. JOURNAL OF HAZARDOUS MATERIALS 2019; 378:120859. [PMID: 31327574 PMCID: PMC6833951 DOI: 10.1016/j.jhazmat.2019.120859] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 04/05/2019] [Accepted: 07/01/2019] [Indexed: 05/19/2023]
Abstract
Bioremediation is a sustainable treatment strategy which remains challenging to implement especially in heterogeneous environments such as soil and sediment. Herein, we present a novel precision bioremediation framework that integrates amplicon based metagenomic analysis and chemical profiling. We applied this approach to samples obtained at a site contaminated with polycyclic aromatic hydrocarbons (PAHs). Geobacter spp. were identified as biostimulation targets because they were one of the most abundant genera and previously identified to carry relevant degradative genes. Mycobacterium and Sphingomonads spp. were identified as bioaugmentation and genetic bioaugmentation targets, respectively, due to their positive associations with PAHs and their high abundance and species diversity at all sampling locations. Overall, this case study suggests this framework can help identify bacterial targets for precision bioremediation. However, it is imperative that we continue to build our databases as the power of metagenomic based approaches remains limited to microorganisms currently in our databases.
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Affiliation(s)
- Lauren K Redfern
- Pratt School of Engineering, Department of Civil and Environmental Engineering, Duke University, Durham, NC 27713, United States
| | - Courtney M Gardner
- Pratt School of Engineering, Department of Civil and Environmental Engineering, Duke University, Durham, NC 27713, United States
| | - Emina Hodzic
- Nicholas School of the Environment, Duke University, Durham, NC 27713, United States
| | - P Lee Ferguson
- Pratt School of Engineering, Department of Civil and Environmental Engineering, Duke University, Durham, NC 27713, United States; Nicholas School of the Environment, Duke University, Durham, NC 27713, United States
| | - Helen Hsu-Kim
- Pratt School of Engineering, Department of Civil and Environmental Engineering, Duke University, Durham, NC 27713, United States
| | - Claudia K Gunsch
- Pratt School of Engineering, Department of Civil and Environmental Engineering, Duke University, Durham, NC 27713, United States.
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Jin J, Wang M, Lu W, Zhang L, Jiang Q, Jin Y, Lu K, Sun S, Cao Q, Wang Y, Xiao M. Effect of plants and their root exudate on bacterial activities during rhizobacterium-plant remediation of phenol from water. ENVIRONMENT INTERNATIONAL 2019; 127:114-124. [PMID: 30913456 DOI: 10.1016/j.envint.2019.03.015] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 02/20/2019] [Accepted: 03/07/2019] [Indexed: 06/09/2023]
Abstract
We investigated remediation of phenol from water using microbe-plant partnerships. Co-introduction of maize seedlings, Pseudomonas fluorescens rifampicin-resistant P13 and P. stutzeri P7 carrying self-transmissible TOL-like plasmids reduced phenol content in water at lower phenol concentrations (25, 50, and 75 mg/L), similar to individual introduction of the bacteria. Co-introduction of plants and bacteria significantly reduced phenol content in water at higher phenol concentrations (100, 125, and 150 mg/L) compared to using individual introduction of the bacteria. Moreover, TOL-like plasmids were transferred from P7 to P13. Addition of plants promoted the growth of both strains, leading to increased plasmid transfer. At higher phenol concentrations, addition of plants resulted in increases of catechol 2, 3-dioxygenase (C23O) activity and reduction in level of reactive oxygen species (ROS) of bacteria in the degradation experiments. Increased plasmid transfer and C23O activity and reduction in ROS level might be the major reasons why plants promote bacterial degradation of phenol at higher phenol concentrations. Furthermore, root exudate of maize seedlings and artificial root exudate (ARE) constructed using major components of the root exudate had the same effects on bacterial activities. Unlike the ARE, deletion of glucose, arabinose, or fructose or all the monosaccharides from ARE resulted in no increase in numbers of both strains and in plasmid transfer. At the higher phenol concentrations, deletion of glutamic acid, aspartic acid, alanine, or glycine or all the amino acids did not stimulate bacterial C23O activity. Deletion of fumaric, oxaloacetic or citric acids still reduced bacterial ROS level as ARE did, but, deletion of all the organic acids or DIMBOA, a hydroxamic acid, did not reduce bacterial ROS level as ARE did. The data showed that each monosaccharide might be important for sufficient numbers of plant-associated bacteria and increased plasmid transfer while each amino acid might be important for maintaining bacterial C23O activity and that DIMBOA might be responsible for the decrease in ROS levels. These results are the basis for efficient remediation of phenol from water by microbe-plant partnerships and further studies on the mechanism of rhizobacterium-plant interaction.
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Affiliation(s)
- Jieren Jin
- Development Center of Plant Germplasm, College of Life Sciences, Shanghai Normal University, Shanghai 200234, China
| | - Min Wang
- Shanghai Academy of Environmental Sciences, Shanghai 200233, China
| | - Wenwei Lu
- Development Center of Plant Germplasm, College of Life Sciences, Shanghai Normal University, Shanghai 200234, China; Key Laboratory of Urban Agriculture, Ministry of Agriculture, Shanghai 200240, China
| | - Lei Zhang
- Development Center of Plant Germplasm, College of Life Sciences, Shanghai Normal University, Shanghai 200234, China
| | - Qiuyan Jiang
- Development Center of Plant Germplasm, College of Life Sciences, Shanghai Normal University, Shanghai 200234, China
| | - Yeqing Jin
- Development Center of Plant Germplasm, College of Life Sciences, Shanghai Normal University, Shanghai 200234, China
| | - Kaiheng Lu
- Development Center of Plant Germplasm, College of Life Sciences, Shanghai Normal University, Shanghai 200234, China
| | - Shurong Sun
- Development Center of Plant Germplasm, College of Life Sciences, Shanghai Normal University, Shanghai 200234, China
| | - Qin Cao
- Development Center of Plant Germplasm, College of Life Sciences, Shanghai Normal University, Shanghai 200234, China
| | - Yujing Wang
- Development Center of Plant Germplasm, College of Life Sciences, Shanghai Normal University, Shanghai 200234, China; Key Laboratory of Urban Agriculture, Ministry of Agriculture, Shanghai 200240, China
| | - Ming Xiao
- Development Center of Plant Germplasm, College of Life Sciences, Shanghai Normal University, Shanghai 200234, China; Key Laboratory of Urban Agriculture, Ministry of Agriculture, Shanghai 200240, China.
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7
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Garbisu C, Garaiyurrebaso O, Epelde L, Grohmann E, Alkorta I. Plasmid-Mediated Bioaugmentation for the Bioremediation of Contaminated Soils. Front Microbiol 2017; 8:1966. [PMID: 29062312 PMCID: PMC5640721 DOI: 10.3389/fmicb.2017.01966] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2017] [Accepted: 09/25/2017] [Indexed: 11/29/2022] Open
Abstract
Bioaugmentation, or the inoculation of microorganisms (e.g., bacteria harboring the required catabolic genes) into soil to enhance the rate of contaminant degradation, has great potential for the bioremediation of soils contaminated with organic compounds. Regrettably, cell bioaugmentation frequently turns into an unsuccessful initiative, owing to the rapid decrease of bacterial viability and abundance after inoculation, as well as the limited dispersal of the inoculated bacteria in the soil matrix. Genes that encode the degradation of organic compounds are often located on plasmids and, consequently, they can be spread by horizontal gene transfer into well-established, ecologically competitive, indigenous bacterial populations. Plasmid-mediated bioaugmentation aims to stimulate the spread of contaminant degradation genes among indigenous soil bacteria by the introduction of plasmids, located in donor cells, harboring such genes. But the acquisition of plasmids by recipient cells can affect the host’s fitness, a crucial aspect for the success of plasmid-mediated bioaugmentation. Besides, environmental factors (e.g., soil moisture, temperature, organic matter content) can play important roles for the transfer efficiency of catabolic plasmids, the expression of horizontally acquired genes and, finally, the contaminant degradation activity. For plasmid-mediated bioaugmentation to be reproducible, much more research is needed for a better selection of donor bacterial strains and accompanying plasmids, together with an in-depth understanding of indigenous soil bacterial populations and the environmental conditions that affect plasmid acquisition and the expression and functioning of the catabolic genes of interest.
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Affiliation(s)
- Carlos Garbisu
- Soil Microbial Ecology Group, Department of Conservation of Natural Resources, Neiker Tecnalia, Derio, Spain
| | - Olatz Garaiyurrebaso
- Instituto Biofisika (UPV/EHU, CSIC), Department of Biochemistry and Molecular Biology, University of the Basque Country, Bilbao, Spain
| | - Lur Epelde
- Soil Microbial Ecology Group, Department of Conservation of Natural Resources, Neiker Tecnalia, Derio, Spain
| | | | - Itziar Alkorta
- Soil Microbial Ecology Group, Department of Conservation of Natural Resources, Neiker Tecnalia, Derio, Spain
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8
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Chen J, Zhang L, Jin Q, Su C, Zhao L, Liu X, Kou S, Wang Y, Xiao M. Bioremediation of phenol in soil through using a mobile plant-endophyte system. CHEMOSPHERE 2017; 182:194-202. [PMID: 28499180 DOI: 10.1016/j.chemosphere.2017.05.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Revised: 04/27/2017] [Accepted: 05/03/2017] [Indexed: 06/07/2023]
Abstract
Plant-endophyte remediation of volatile pollutants in soil is an emerging technology. For more efficient application, plant-endophyte systems were formed through stimulation of transfer of degradative plasmids in plant tissue by co-inoculation of corn, wheat or tomato seedlings with Pseudomonas fluorescens TP13 carrying a self-transmissible degradative plasmid, and P. fluorescens streptomycin-resistant P13 strain. The corn-TP13-P13 (CTP) system had higher degradation activity than other plant-endophyte systems. Transplanting the CTP, from loam to sandy clay loam soil, from greenhouse to field trials, almost completely removed phenol from contaminated soils in 15 d. Intact transplantation of the CTP to contaminated soils was more efficient than co-transplanting of phenol-degrading bacteria and plant in detoxification of phenol. After the experiments the harvested CPT still exhibited remarkable bioremediation activity. The number of degradative plasmid-carrying endophytic bacteria in the CTP system was just slightly more than in the corn seedlings inoculated with TP13 alone, but the former substantially surpassed the latter in phenol-degrading activity, probably due to stimulation of transfer of the degradative plasmids among endophytic bacteria in plant tissues. More degradative plasmid-carrying bacteria colonized bioremediating soil and plant tissues, and higher plasmid transfer frequency and C23O activity of transconjugant were found in soils for the CTP system compared with other treatments. These results showed that the CTP system is a valuable tool to degrade volatile organic pollutants and transfer of degradative plasmids in plant tissues is important for construction of a mobile plant-endophyte system applied in bioremediation of volatile pollutants.
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Affiliation(s)
- Jun Chen
- Development Center of Plant Germplasm, College of Life and Environment Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Li Zhang
- Development Center of Plant Germplasm, College of Life and Environment Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Qing Jin
- Development Center of Plant Germplasm, College of Life and Environment Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Cuizhu Su
- Development Center of Plant Germplasm, College of Life and Environment Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Lei Zhao
- Development Center of Plant Germplasm, College of Life and Environment Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Xiaoxiang Liu
- Development Center of Plant Germplasm, College of Life and Environment Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Shumeng Kou
- Development Center of Plant Germplasm, College of Life and Environment Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Yujing Wang
- Development Center of Plant Germplasm, College of Life and Environment Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Ming Xiao
- Development Center of Plant Germplasm, College of Life and Environment Sciences, Shanghai Normal University, Shanghai, 200234, China.
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9
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Redfern LK, Gunsch CK. Endophytic Phytoaugmentation: Treating Wastewater and Runoff Through Augmented Phytoremediation. Ind Biotechnol (New Rochelle N Y) 2016; 12:83-90. [PMID: 27158249 PMCID: PMC4835827 DOI: 10.1089/ind.2015.0016] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Limited options exist for efficiently and effectively treating water runoff from agricultural fields and landfills. Traditional treatments include excavation, transport to landfills, incineration, stabilization, and vitrification. In general, treatment options relying on biological methods such as bioremediation have the ability to be applied in situ and offer a sustainable remedial option with a lower environmental impact and reduced long-term operating expenses. These methods are generally considered ecologically friendly, particularly when compared to traditional physicochemical cleanup options. Phytoremediation, which relies on plants to take up and/or transform the contaminant of interest, is another alternative treatment method which has been developed. However, phytoremediation is not widely used, largely due to its low treatment efficiency. Endophytic phytoaugmentation is a variation on phytoremediation that relies on augmenting the phytoremediating plants with exogenous strains to stimulate associated plant-microbe interactions to facilitate and improve remediation efficiency. In this review, we offer a summary of the current knowledge as well as developments in endophytic phytoaugmentation and present some potential future applications for this technology. There has been a limited number of published endophytic phytoaugmentation case studies and much remains to be done to transition lab-scale results to field applications. Future research needs include large-scale endophytic phytoaugmentation experiments as well as the development of more exhaustive tools for monitoring plant-microbe-pollutant interactions.
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Affiliation(s)
- Lauren K Redfern
- Department of Civil and Environmental Engineering, Duke University , Durham, NC
| | - Claudia K Gunsch
- Department of Civil and Environmental Engineering, Duke University , Durham, NC
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Ikuma K, Holzem RM, Gunsch CK. Impacts of organic carbon availability and recipient bacteria characteristics on the potential for TOL plasmid genetic bioaugmentation in soil slurries. CHEMOSPHERE 2012; 89:158-163. [PMID: 22743182 DOI: 10.1016/j.chemosphere.2012.05.086] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Revised: 05/23/2012] [Accepted: 05/25/2012] [Indexed: 06/01/2023]
Abstract
The effectiveness of genetic bioaugmentation relies on efficient plasmid transfer between donor and recipient cells as well as the plasmid's phenotype in the recipient cell. In the present study, the effects of varying organic carbon substrates, initial recipient-to-donor cell density ratios, and mixtures of known recipient bacterial strains on the conjugation and function of a TOL plasmid were tested in sterile soil slurry batch reactors. The presence of soil organic carbon was sufficient in ensuring TOL plasmid transconjugant occurrence (up to 2.1±0.5%) for most recipient strains in soil slurry batch mating experiments. The addition of glucose had limited effects on transconjugant occurrence; however, glucose amendment increased the specific toluene degradation rates of some Enterobacteriaceae transconjugants in soil slurry. Initial cell density ratios and mixtures of recipient strains had smaller impacts on plasmid conjugation and resulting phenotype functionality. These observations suggest that genetic bioaugmentation may be improved by minimal altering of environmental conditions.
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Affiliation(s)
- Kaoru Ikuma
- Department of Civil and Environmental Engineering, Duke University, Durham, NC 27708, USA
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Ikuma K, Gunsch CK. Genetic bioaugmentation as an effective method for in situ bioremediation: functionality of catabolic plasmids following conjugal transfers. Bioengineered 2012; 3:236-41. [PMID: 22705839 DOI: 10.4161/bioe.20551] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Genetic bioaugmentation is an in situ bioremediation method that stimulates horizontal transfer of catabolic plasmids between exogenous donor cells and indigenous bacteria to increase the biodegradation potential of contaminants. A critical outcome of genetic bioaugmentation is the expression of an active catabolic phenotype upon plasmid conjugation. Using a pWW0-derivative TOL plasmid, we showed that certain genetic characteristics of the recipient bacteria, including genomic guanine-cytosine (G + C) content and phylogeny, may limit the expression of the transferred catabolic pathway. However, such genetic limitations observed in transconjugants could be overcome by the presence of an additional carbon source. Glucose and Luria-Bertani broth were shown to enhance the toluene degradation rates of transconjugants; these enhancement effects were dependent on transconjugant genomic G + C contents. Based on these observations, thorough genetic characterization of the indigenous microbial community in the contaminated environment of interest may provide a predictive tool for assessing the success of genetic bioaugmentation.
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Affiliation(s)
- Kaoru Ikuma
- Department of Civil and Environmental Engineering, Duke University, Durham, NC, USA
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12
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Ikuma K, Gunsch CK. Functionality of the TOL plasmid under varying environmental conditions following conjugal transfer. Appl Microbiol Biotechnol 2012; 97:395-408. [PMID: 22367613 DOI: 10.1007/s00253-012-3949-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Revised: 01/19/2012] [Accepted: 02/06/2012] [Indexed: 10/28/2022]
Abstract
Conjugation of catabolic plasmids in contaminated environments is a naturally occurring horizontal gene transfer phenomenon, which could be utilized in genetic bioaugmentation. The potentially important parameters for genetic bioaugmentation include gene regulation of transferred catabolic plasmids that may be controlled by the genetic characteristics of transconjugants as well as environmental conditions that may alter the expression of the contaminant-degrading phenotype. This study showed that both genomic guanine-cytosine contents and phylogenetic characteristics of transconjugants were important in controlling the phenotype functionality of the TOL plasmid. These genetic characteristics had no apparent impact on the stability of the TOL plasmid, which was observed to be highly variable among strains. Within the environmental conditions tested, the addition of glucose resulted in the largest enhancement of the activities of enzymes encoded by the TOL plasmid in all transconjugant strains. Glucose (1 g/L) enhanced the phenotype functionality by up to 16.4 (±2.22), 30.8 (±7.03), and 90.8 (±4.56)-fold in toluene degradation rates, catechol 2,3-dioxygenase enzymatic activities, and xylE gene expression, respectively. These results suggest that genetic limitations of the expression of horizontally acquired genes may be overcome by the presence of alternate carbon substrates. Such observations may be utilized in improving the effectiveness of genetic bioaugmentation.
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Affiliation(s)
- Kaoru Ikuma
- Department of Civil and Environmental Engineering, Duke University, 121 Hudson Hall, Box 90287, Durham, NC 27708-0287, USA
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