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Hu X, Li D, Gao Y, Mu L, Zhou Q. Knowledge gaps between nanotoxicological research and nanomaterial safety. ENVIRONMENT INTERNATIONAL 2016; 94:8-23. [PMID: 27203780 DOI: 10.1016/j.envint.2016.05.001] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2016] [Revised: 05/01/2016] [Accepted: 05/02/2016] [Indexed: 06/05/2023]
Abstract
With the wide research and application of nanomaterials in various fields, the safety of nanomaterials attracts much attention. An increasing number of reports in the literature have shown the adverse effects of nanomaterials, representing the quick development of nanotoxicology. However, many studies in nanotoxicology have not reflected the real nanomaterial safety, and the knowledge gaps between nanotoxicological research and nanomaterial safety remain large. Considering the remarkable influence of biological or environmental matrices (e.g., biological corona) on nanotoxicity, the situation of performing nanotoxicological experiments should be relevant to the environment and humans. Given the possibility of long-term and low-concentration exposure of nanomaterials, the reversibility of and adaptation to nanotoxicity, and the transgenerational effects should not be ignored. Different from common pollutants, the specific analysis methodology for nanotoxicology need development and exploration furthermore. High-throughput assay integrating with omics was highlighted in the present review to globally investigate nanotoxicity. In addition, the biological responses beyond individual levels, special mechanisms and control of nanotoxicity deserve more attention. The progress of nanotoxicology has been reviewed by previous articles. This review focuses on the blind spots in nanotoxicological research and provides insight into what we should do in future work to support the healthy development of nanotechnology and the evaluation of real nanomaterial safety.
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Affiliation(s)
- Xiangang Hu
- Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China.
| | - Dandan Li
- Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China
| | - Yue Gao
- Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China
| | - Li Mu
- Institute of Agro-Environmental Protection, Ministry of Agriculture, Tianjin 300191, China
| | - Qixing Zhou
- Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China.
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52
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Liang B, Kong D, Ma J, Wen C, Yuan T, Lee DJ, Zhou J, Wang A. Low temperature acclimation with electrical stimulation enhance the biocathode functioning stability for antibiotics detoxification. WATER RESEARCH 2016; 100:157-168. [PMID: 27183211 DOI: 10.1016/j.watres.2016.05.028] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Revised: 05/07/2016] [Accepted: 05/07/2016] [Indexed: 06/05/2023]
Abstract
Improvement of the stability of functional microbial communities in wastewater treatment system is critical to accelerate pollutants detoxification in cold regions. Although biocathode communities could accelerate environmental pollutants degradation, how to acclimate the cold stress and to improve the catalytic stability of functional microbial communities are remain poorly understood. Here we investigated the structural and functional responses of antibiotic chloramphenicol (CAP) reducing biocathode communities to constant low temperature 10 °C (10-biocathode) and temperature elevation from 10 °C to 25 °C (S25-biocathode). Our results indicated that the low temperature acclimation with electrical stimulation obviously enhanced the CAP nitro group reduction efficiency when comparing the aromatic amine product AMCl2 formation efficiency with the 10-biocathode and S25-biocathode under the opened and closed circuit conditions. The 10-biocathode generated comparative AMCl maximum as the S25-biocathode but showed significant lower dehalogenation rate of AMCl2 to AMCl. The continuous low temperature and temperature elevation both enriched core functional community in the 10-biocathode and S25-biocathode, respectively. The 10-biocathode functioning stability maintained mainly through selectively enriching cold-adapted functional species, coexisting metabolically similar nitroaromatics reducers and maintaining the relative abundance of key electrons transfer genes. This study provides new insights into biocathode functioning stability for accelerating environmental pollutants degradation in cold wastewater system.
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Affiliation(s)
- Bin Liang
- Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, China; Institute for Environmental Genomics and Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK 73019, USA
| | - Deyong Kong
- Shenyang Academy of Environmental Sciences, Shenyang, 110167, China; State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, China
| | - Jincai Ma
- College of Environment and Resources, Jilin University, Changchun, 130021, China
| | - Chongqing Wen
- Institute for Environmental Genomics and Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK 73019, USA
| | - Tong Yuan
- Institute for Environmental Genomics and Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK 73019, USA
| | - Duu-Jong Lee
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, China; Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan
| | - Jizhong Zhou
- Institute for Environmental Genomics and Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK 73019, USA
| | - Aijie Wang
- Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, China.
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53
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Chen D, Wang X, Yang K, Wang H. Response of a three dimensional bioelectrochemical denitrification system to the long-term presence of graphene oxide. BIORESOURCE TECHNOLOGY 2016; 214:24-29. [PMID: 27115747 DOI: 10.1016/j.biortech.2016.04.082] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 04/12/2016] [Accepted: 04/16/2016] [Indexed: 06/05/2023]
Abstract
In this study, a three dimensional bioelectrochemical denitrification system (3D-BEDS) was operated under long-term graphene oxide (GO) condition to treat high nitrate polluted water. When GO concentration increased from 0 to 100mgL(-1), nitrate removal efficiency slightly decreased from 99.52% to 94.81%. However, when GO concentration was further increased to 150mgL(-1), the denitrification efficiency dramatically decreased to 74.95%. Increasing GO concentration in this BEDS resulted in decreased community richness, and the abundances of the dominant bacterial communities presented obvious shift. The abundances of denitrifying genes napA, nirS, and nirK showed no obvious changes with GO concentration lower than 50mgL(-1). However, the abundances of the three genes decreased when GO concentration was further increased to higher than 100mgL(-1). The increased lactate dehydrogenase (LDH) release and reactive oxygen species (ROS) production demonstrated that long-term presence of GO caused chronic impacts onto microorganisms in this BEDS.
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Affiliation(s)
- Dan Chen
- School of Civil Engineering, Wuhan University, Wuhan 430072, China
| | - Xufeng Wang
- School of Civil Engineering, Wuhan University, Wuhan 430072, China
| | - Kai Yang
- School of Civil Engineering, Wuhan University, Wuhan 430072, China
| | - Hongyu Wang
- School of Civil Engineering, Wuhan University, Wuhan 430072, China.
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54
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Qu Y, Zhang X, Shen W, Ma Q, You S, Pei X, Li S, Ma F, Zhou J. Illumina MiSeq sequencing reveals long-term impacts of single-walled carbon nanotubes on microbial communities of wastewater treatment systems. BIORESOURCE TECHNOLOGY 2016; 211:209-215. [PMID: 27017131 DOI: 10.1016/j.biortech.2016.03.043] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Revised: 03/04/2016] [Accepted: 03/08/2016] [Indexed: 06/05/2023]
Abstract
In this study, phenol wastewater treatment systems treated with different concentrations of single-walled carbon nanotubes (SWCNTs) (0-3.5g/L) were exposed to phenol and carbon nanotubes (CNTs) shock loadings to investigate the long-term impacts of SWCNTs on microbial communities. Phenol removal remained high efficiency (>98%) in SWCNTs-treated groups but decreased in non-treated group (85.1±1.9%) when exposed to high concentration of phenol (500mg/L). However, secondary dosing of SWCNTs in SWCNTs-treated groups would decrease the phenol removal efficiency. Illumina MiSeq sequencing revealed that the diversity, richness and structure of microbial communities were shifted under phenol shock loading, especially under high phenol concentration, but not under CNTs shock loading. In response to phenol and CNTs shock loadings, Rudaea, Burkholderia, Sphingomonas, Acinetobacter, Methylocystis and Thauera became dominant genera, which should be involved in phenol removal. These results suggested that a proper amount of SWCNTs might have positive effects on phenol wastewater treatment systems.
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Affiliation(s)
- Yuanyuan Qu
- State Key Laboratory of Fine Chemicals, Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Xuwang Zhang
- State Key Laboratory of Fine Chemicals, Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Wenli Shen
- State Key Laboratory of Fine Chemicals, Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Qiao Ma
- State Key Laboratory of Fine Chemicals, Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Shengnan You
- State Key Laboratory of Fine Chemicals, Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Xiaofang Pei
- State Key Laboratory of Fine Chemicals, Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Shuzhen Li
- State Key Laboratory of Fine Chemicals, Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Fang Ma
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
| | - Jiti Zhou
- State Key Laboratory of Fine Chemicals, Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
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55
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Qu Y, Wang J, Zhou H, Ma Q, Zhang Z, Li D, Shen W, Zhou J. Concentration-dependent effects of carbon nanotubes on growth and biphenyl degradation of Dyella ginsengisoli LA-4. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:2864-2872. [PMID: 26459414 DOI: 10.1007/s11356-015-5532-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 10/05/2015] [Indexed: 06/05/2023]
Abstract
To enrich the understanding on interactions between carbon nanotubes (CNTs) and microbes, the responses of a biphenyl-degrading bacterium to single-walled carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWCNTs) and carboxyl single-walled carbon nanotubes (SWCNT-COOHs) were investigated. Electron microscopy, viability test, cellular membrane integrity, and oxidative stress analyses indicated that CNT toxicity was mainly caused by physical piercing. Apart from antibacterial activities, the experimental results showed that CNTs enhanced cell growth and biphenyl degradation at certain concentrations (1.0-1.5 mg/L). The CNTs aggregated and adsorbed cells and biphenyl to form a CNTs-cells-biphenyl coexisting system, thus it created a suitable microenvironment for cell attachment and proliferation where the cells could utilize biphenyl easier for their growth. To the best of our knowledge, this is the first report about CNTs' impact on biodegradation efficacy and growth of aromatic-degrading bacterium.
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Affiliation(s)
- Yuanyuan Qu
- State Key Laboratory of Fine Chemicals, Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China.
| | - Jingwei Wang
- State Key Laboratory of Fine Chemicals, Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China
| | - Hao Zhou
- State Key Laboratory of Fine Chemicals, Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Food and Environmental, Dalian University of Technology, Panjin, 124000, China
| | - Qiao Ma
- State Key Laboratory of Fine Chemicals, Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China
| | - Zhaojing Zhang
- State Key Laboratory of Fine Chemicals, Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China
| | - Duanxing Li
- State Key Laboratory of Fine Chemicals, Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China
| | - Wenli Shen
- State Key Laboratory of Fine Chemicals, Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China
| | - Jiti Zhou
- State Key Laboratory of Fine Chemicals, Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China
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56
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Huang W, Xiang G, Jiang D, Liu L, Liu C, Liu F, Pu X. Electrochemical Immunoassay forCytomegalovirusAntigen Detection with Multiple Signal Amplification Using HRP and Pt-Pd Nanoparticles Functionalized Single-walled Carbon Nanohorns. ELECTROANAL 2016. [DOI: 10.1002/elan.201501056] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Miran W, Nawaz M, Jang J, Lee DS. Effect of wastewater containing multi-walled carbon nanotubes on dual-chamber microbial fuel cell performance. RSC Adv 2016. [DOI: 10.1039/c6ra20128h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2022] Open
Abstract
The effect of wastewater containing MWCNTs on MFC performance was evaluated. MWCNTs addition resulted in a higher voltage/power density generation and COD/TOC removal. Low LDH release and a compact biofilm showed insignificant electricigen damage.
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Affiliation(s)
- Waheed Miran
- Department of Environmental Engineering
- Kyungpook National University
- Daegu 41566
- Republic of Korea
| | - Mohsin Nawaz
- Department of Environmental Engineering
- Kyungpook National University
- Daegu 41566
- Republic of Korea
| | - Jiseon Jang
- Department of Environmental Engineering
- Kyungpook National University
- Daegu 41566
- Republic of Korea
| | - Dae Sung Lee
- Department of Environmental Engineering
- Kyungpook National University
- Daegu 41566
- Republic of Korea
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58
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Ma Q, Qu Y, Zhang X, Liu Z, Li H, Zhang Z, Wang J, Shen W, Zhou J. Systematic investigation and microbial community profile of indole degradation processes in two aerobic activated sludge systems. Sci Rep 2015; 5:17674. [PMID: 26657581 PMCID: PMC4675989 DOI: 10.1038/srep17674] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 11/03/2015] [Indexed: 01/26/2023] Open
Abstract
Indole is widely spread in various environmental matrices. Indole degradation by bacteria has been reported previously, whereas its degradation processes driven by aerobic microbial community were as-yet unexplored. Herein, eight sequencing batch bioreactors fed with municipal and coking activated sludges were constructed for aerobic treatment of indole. The whole operation processes contained three stages, i.e. stage I, glucose and indole as carbon sources; stage II, indole as carbon source; and stage III, indole as carbon and nitrogen source. Indole could be completely removed in both systems. Illumina sequencing revealed that alpha diversity was reduced after indole treatment and microbial communities were significantly distinct among the three stages. At genus level, Azorcus and Thauera were dominant species in stage I in both systems, while Alcaligenes, Comamonas and Pseudomonas were the core genera in stage II and III in municipal sludge system, Alcaligenes and Burkholderia in coking sludge system. In addition, four strains belonged to genera Comamonas, Burkholderia and Xenophilus were isolated using indole as sole carbon source. Burkholderia sp. IDO3 could remove 100 mg/L indole completely within 14 h, the highest degradation rate to date. These findings provide novel information and enrich our understanding of indole aerobic degradation processes.
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Affiliation(s)
- Qiao Ma
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, People's Republic of China
| | - Yuanyuan Qu
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, People's Republic of China
| | - Xuwang Zhang
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, People's Republic of China
| | - Ziyan Liu
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, People's Republic of China
| | - Huijie Li
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, People's Republic of China
| | - Zhaojing Zhang
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, People's Republic of China
| | - Jingwei Wang
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, People's Republic of China
| | - Wenli Shen
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, People's Republic of China
| | - Jiti Zhou
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, People's Republic of China
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Grijalbo L, Garbisu C, Martín I, Etxebarria J, Gutierrez-Mañero FJ, Lucas Garcia JA. Functional diversity and dynamics of bacterial communities in a membrane bioreactor for the treatment of metal-working fluid wastewater. JOURNAL OF WATER AND HEALTH 2015; 13:1006-1019. [PMID: 26608762 DOI: 10.2166/wh.2015.079] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
An extensive microbiological study has been carried out in a membrane bioreactor fed with activated sludge and metal-working fluids. Functional diversity and dynamics of bacterial communities were studied with different approaches. Functional diversity of culturable bacterial communities was studied with different Biolog™ plates. Structure and dynamics of bacterial communities were studied in culturable and in non-culturable fractions using a 16S rRNA analysis. Among the culturable bacteria, Alphaproteobacteria and Gammaproteobacteria were the predominant classes. However, changes in microbial community structure were detected over time. Culture-independent analysis showed that Betaproteobacteria was the most frequently detected class in the membrane bioreactor (MBR) community with Zoogloea and Acidovorax as dominant genera. Also, among non-culturable bacteria, a process of succession was observed. Longitudinal structural shifts observed were more marked for non-culturable than for culturable bacteria, pointing towards an important role in the MBR performance. Microbial community metabolic abilities assessed with Biolog™ Gram negative, Gram positive and anaerobic plates also showed differences over time for Shannon's diversity index, kinetics of average well colour development, and the intensely used substrates by bacterial community in each plate.
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Affiliation(s)
- Lucía Grijalbo
- Department of Pharmaceutical and Health Sciences, Facultad Farmacia, Universidad San Pablo CEU., Urb. Monteprincipe, Boadilla del Monte, 28668 Madrid, Spain E-mail:
| | - Carlos Garbisu
- Department of Ecology and Natural Resources, Soil Microbial Ecology Group, NEIKER-Tecnalia, c/Berreaga 1, E-48160 Derio, Spain
| | - Iker Martín
- Department of Ecology and Natural Resources, Soil Microbial Ecology Group, NEIKER-Tecnalia, c/Berreaga 1, E-48160 Derio, Spain
| | - Javier Etxebarria
- GAIKER Tecnological Centre, IK4 Research Alliance, E-48170 Zamudio, Spain
| | - F Javier Gutierrez-Mañero
- Department of Pharmaceutical and Health Sciences, Facultad Farmacia, Universidad San Pablo CEU., Urb. Monteprincipe, Boadilla del Monte, 28668 Madrid, Spain E-mail:
| | - Jose Antonio Lucas Garcia
- Department of Pharmaceutical and Health Sciences, Facultad Farmacia, Universidad San Pablo CEU., Urb. Monteprincipe, Boadilla del Monte, 28668 Madrid, Spain
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Microbial Community Dynamics and Activity Link to Indigo Production from Indole in Bioaugmented Activated Sludge Systems. PLoS One 2015; 10:e0138455. [PMID: 26372223 PMCID: PMC4570806 DOI: 10.1371/journal.pone.0138455] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 08/31/2015] [Indexed: 12/02/2022] Open
Abstract
Biosynthesis of the popular dyestuff indigo from indole has been comprehensively studied using pure cultures, but less has been done to characterize the indigo production by microbial communities. In our previous studies, a wild strain Comamonas sp. MQ was isolated from activated sludge and the recombinant Escherichia colinagAc carrying the naphthalene dioxygenase gene (nag) from strain MQ was constructed, both of which were capable of producing indigo from indole. Herein, three activated sludge systems, G1 (non-augmented control), G2 (augmented with Comamonas sp. MQ), and G3 (augmented with recombinant E. colinagAc), were constructed to investigate indigo production. After 132-day operation, G3 produced the highest yields of indigo (99.5 ± 3.0 mg/l), followed by G2 (27.3 ± 1.3 mg/l) and G1 (19.2 ± 1.2 mg/l). The microbial community dynamics and activities associated with indigo production were analyzed by Illumina Miseq sequencing of 16S rRNA gene amplicons. The inoculated strain MQ survived for at least 30 days, whereas E. colinagAc was undetectable shortly after inoculation. Quantitative real-time PCR analysis suggested the abundance of naphthalene dioxygenase gene (nagAc) from both inoculated strains was strongly correlated with indigo yields in early stages (0–30 days) (P < 0.001) but not in later stages (30–132 days) (P > 0.10) of operation. Based on detrended correspondence analysis (DCA) and dissimilarity test results, the communities underwent a noticeable shift during the operation. Among the four major genera (> 1% on average), the commonly reported indigo-producing populations Comamonas and Pseudomonas showed no positive relationship with indigo yields (P > 0.05) based on Pearson correlation test, while Alcaligenes and Aquamicrobium, rarely reported for indigo production, were positively correlated with indigo yields (P < 0.05). This study should provide new insights into our understanding of indigo bio-production by microbial communities.
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