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Kordesedehi R, Shahpiri A, Asadollahi MA, Biria D, Nikel PI. Enhanced chaotrope tolerance and (S)-2-hydroxypropiophenone production by recombinant Pseudomonas putida engineered with Pprl from Deinococcus radiodurans. Microb Biotechnol 2024; 17:e14448. [PMID: 38498302 PMCID: PMC10946676 DOI: 10.1111/1751-7915.14448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 03/01/2024] [Accepted: 03/04/2024] [Indexed: 03/20/2024] Open
Abstract
Pseudomonas putida is a soil bacterium with multiple uses in fermentation and biotransformation processes. P. putida ATCC 12633 can biotransform benzaldehyde and other aldehydes into valuable α-hydroxyketones, such as (S)-2-hydroxypropiophenone. However, poor tolerance of this strain toward chaotropic aldehydes hampers efficient biotransformation processes. To circumvent this problem, we expressed the gene encoding the global regulator PprI from Deinococcus radiodurans, an inducer of pleiotropic proteins promoting DNA repair, in P. putida. Fine-tuned gene expression was achieved using an expression plasmid under the control of the LacIQ /Ptrc system, and the cross-protective role of PprI was assessed against multiple stress treatments. Moreover, the stress-tolerant P. putida strain was tested for 2-hydroxypropiophenone production using whole resting cells in the presence of relevant aldehyde substrates. P. putida cells harbouring the global transcriptional regulator exhibited high tolerance toward benzaldehyde, acetaldehyde, ethanol, butanol, NaCl, H2 O2 and thermal stress, thereby reflecting the multistress protection profile conferred by PprI. Additionally, the engineered cells converted aldehydes to 2-hydroxypropiophenone more efficiently than the parental P. putida strain. 2-Hydroxypropiophenone concentration reached 1.6 g L-1 upon a 3-h incubation under optimized conditions, at a cell concentration of 0.033 g wet cell weight mL-1 in the presence of 20 mM benzaldehyde and 600 mM acetaldehyde. Product yield and productivity were 0.74 g 2-HPP g-1 benzaldehyde and 0.089 g 2-HPP g cell dry weight-1 h-1 , respectively, 35% higher than the control experiments. Taken together, these results demonstrate that introducing PprI from D. radiodurans enhances chaotrope tolerance and 2-HPP production in P. putida ATCC 12633.
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Affiliation(s)
- Reihaneh Kordesedehi
- Department of Biotechnology, Faculty of Biological Science and Technology, University of Isfahan, Isfahan, Iran
| | - Azar Shahpiri
- Department of Biotechnology, College of Agriculture, Isfahan University of Technology, Isfahan, Iran
| | - Mohammad Ali Asadollahi
- Department of Biotechnology, Faculty of Biological Science and Technology, University of Isfahan, Isfahan, Iran
| | - Davoud Biria
- Department of Biotechnology, Faculty of Biological Science and Technology, University of Isfahan, Isfahan, Iran
| | - Pablo Iván Nikel
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kongens Lyngby, Denmark
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Guo X, Qiu L, Liang Z, Lu Q, Wang S, Shim H. Isolation and characterization of Rhodococcus sp. GG1 for metabolic degradation of chloroxylenol. CHEMOSPHERE 2023; 338:139462. [PMID: 37437623 DOI: 10.1016/j.chemosphere.2023.139462] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 05/28/2023] [Accepted: 07/08/2023] [Indexed: 07/14/2023]
Abstract
The coronavirus disease 2019 (COVID-19) pandemic has significantly increased the demand of disinfectant use. Chloroxylenol (para-chloro-meta-xylenol, PCMX) as the major antimicrobial ingredient of disinfectant has been widely detected in water environments, with identified toxicity and potential risk. The assessment of PCMX in domestic wastewater of Macau Special Administrative Region (SAR) showed a positive correlation between PCMX concentration and population density. An indigenous PCMX degrader, identified as Rhodococcus sp. GG1, was isolated and found capable of completely degrading PCMX (50 mg L-1) within 36 h. The growth kinetics followed Haldane's inhibition model, with maximum specific growth rate, half-saturation constant, and inhibition constant of 0.38 h-1, 7.64 mg L-1, and 68.08 mg L-1, respectively. The degradation performance was enhanced by optimizing culture conditions, while the presence of additional carbon source stimulated strain GG1 to alleviate inhibition from high concentrations of PCMX. In addition, strain GG1 showed good environmental adaptability, degrading PCMX efficiently in different environmental aqueous matrices. A potential degradation pathway was identified, with 2,6-dimethylhydroquinone as a major intermediate metabolite. Cytochrome P450 (CYP450) was found to play a key role in dechlorinating PCMX via hydroxylation and also catalyzed the hydroxylated dechlorination of other halo-phenolic contaminants through co-metabolism. This study characterizes an aerobic bacterial pure culture capable of degrading PCMX metabolically, which could be promising in effective bioremediation of PCMX-contaminated sites and in treatment of PCMX-containing waste streams.
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Affiliation(s)
- Xiaoyuan Guo
- Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Macau SAR, China
| | - Lan Qiu
- Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Macau SAR, China
| | - Zhiwei Liang
- Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Macau SAR, China; Department of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, China
| | - Qihong Lu
- Department of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, China
| | - Shanquan Wang
- Department of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, China
| | - Hojae Shim
- Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Macau SAR, China.
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Arkhipov VP, Arkhipov RV, Petrova EV, Filippov A. Micellar and solubilizing properties of rhamnolipids. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2023; 61:345-355. [PMID: 36840535 DOI: 10.1002/mrc.5337] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 02/18/2023] [Accepted: 02/22/2023] [Indexed: 05/11/2023]
Abstract
We studied the micellar and solubilizing properties of aqueous solutions of unfractionated rhamnolipids produced by Pseudomonas aeruginosa. We used nuclear magnetic resonance (NMR) diffusometry, dynamic light scattering, and conductometry to measure the critical micelle concentration (CMC) of rhamnolipid solutions and determined the effective hydrodynamic radii of rhamnolipid monomers and micelles. Based on selective measurements of the self-diffusion coefficients of molecules, performed by NMR diffusometry, the solubilizing properties of rhamnolipids were studied depending on their concentration in solution; aromatic hydrocarbons, benzene, toluene, ethylbenzene, and para-xylene were taken as solubilizates. On the basis of the measurement results, we estimated the distribution coefficient of the solubilizate between the micellar (solubilized) and free (in the aqueous phase) states and the solubilizing capacity of rhamnolipid micelles.
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Affiliation(s)
- Victor P Arkhipov
- Department of Physics, Kazan National Research Technological University, Kazan, 420015, Russian Federation
| | - Ruslan V Arkhipov
- Institute of Physics, Kazan Federal University, Kazan, 420008, Russian Federation
| | - Ekaterina V Petrova
- Department of Analytical Chemistry, Kazan National Research Technological University, Kazan, 420015, Russian Federation
| | - Andrei Filippov
- Chemistry of Interfaces, Luleå University of Technology, Luleå, SE-97187, Sweden
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Sonwani RK, Kim KH, Zhang M, Tsang YF, Lee SS, Giri BS, Singh RS, Rai BN. Construction of biotreatment platforms for aromatic hydrocarbons and their future perspectives. JOURNAL OF HAZARDOUS MATERIALS 2021; 416:125968. [PMID: 34492879 DOI: 10.1016/j.jhazmat.2021.125968] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Revised: 04/05/2021] [Accepted: 04/22/2021] [Indexed: 06/13/2023]
Abstract
Aromatic hydrocarbons (AHCs) are one of the major environmental pollutants introduced from both natural and anthropogenic sources. Many AHCs are well known for their toxic, carcinogenic, and mutagenic impact on human health and ecological systems. Biodegradation is an eco-friendly and cost-effective option as microorganisms (e.g., bacteria, fungi, and algae) can efficiently breakdown or transform such pollutants into less harmful and simple metabolites (e.g., carbon dioxide (aerobic), methane (anaerobic), water, and inorganic salts). This paper is organized to offer a state-of-the-art review on the biodegradation of AHCs (monocyclic aromatic hydrocarbons (MAHs) and polycyclic aromatic hydrocarbons (PAHs)) and associated mechanisms. The recent progress in biological treatment using suspended and attached growth bioreactors for the biodegradation of AHCs is also discussed. In addition, various substrate growth and inhibition models are introduced along with the key factors governing their biodegradation kinetics. The growth and inhibition models have helped gain a better understanding of substrate inhibition in biodegradation. Techno-economic analysis (TEA) and life cycle assessment (LCA) aspects are also described to assess the technical, economical, and environmental impacts of the biological treatment system.
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Affiliation(s)
- Ravi Kumar Sonwani
- Department of Chemical Engineering & Technology Indian Institute of Technology (BHU), Varanasi 221005, Uttar Pradesh, India
| | - Ki-Hyun Kim
- Department of Civil and Environmental Engineering, Hanyang University, 222 Wangsimni-Ro, Seoul 04763, Republic of Korea.
| | - Ming Zhang
- Department of Environmental Engineering, China Jiliang University, Hangzhou 310018, China
| | - Yiu Fai Tsang
- Department of Science and Environmental Studies, The Education University of Hong Kong, Tai Po, New Territories 999077, Hong Kong
| | - Sang Soo Lee
- Department of Environmental Engineering, Yonsei University, Wonju 26493, Republic of Korea
| | - Balendu Shekher Giri
- Department of Chemical Engineering & Technology Indian Institute of Technology (BHU), Varanasi 221005, Uttar Pradesh, India
| | - Ram Sharan Singh
- Department of Chemical Engineering & Technology Indian Institute of Technology (BHU), Varanasi 221005, Uttar Pradesh, India
| | - Birendra Nath Rai
- Department of Chemical Engineering & Technology Indian Institute of Technology (BHU), Varanasi 221005, Uttar Pradesh, India
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Weimer A, Kohlstedt M, Volke DC, Nikel PI, Wittmann C. Industrial biotechnology of Pseudomonas putida: advances and prospects. Appl Microbiol Biotechnol 2020; 104:7745-7766. [PMID: 32789744 PMCID: PMC7447670 DOI: 10.1007/s00253-020-10811-9] [Citation(s) in RCA: 97] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 07/23/2020] [Accepted: 08/02/2020] [Indexed: 11/17/2022]
Abstract
Pseudomonas putida is a Gram-negative, rod-shaped bacterium that can be encountered in diverse ecological habitats. This ubiquity is traced to its remarkably versatile metabolism, adapted to withstand physicochemical stress, and the capacity to thrive in harsh environments. Owing to these characteristics, there is a growing interest in this microbe for industrial use, and the corresponding research has made rapid progress in recent years. Hereby, strong drivers are the exploitation of cheap renewable feedstocks and waste streams to produce value-added chemicals and the steady progress in genetic strain engineering and systems biology understanding of this bacterium. Here, we summarize the recent advances and prospects in genetic engineering, systems and synthetic biology, and applications of P. putida as a cell factory. KEY POINTS: • Pseudomonas putida advances to a global industrial cell factory. • Novel tools enable system-wide understanding and streamlined genomic engineering. • Applications of P. putida range from bioeconomy chemicals to biosynthetic drugs.
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Affiliation(s)
- Anna Weimer
- Institute of Systems Biotechnology, Saarland University, Campus A1.5, 66123, Saarbrücken, Germany
| | - Michael Kohlstedt
- Institute of Systems Biotechnology, Saarland University, Campus A1.5, 66123, Saarbrücken, Germany
| | - Daniel C Volke
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, Denmark
| | - Pablo I Nikel
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, Denmark
| | - Christoph Wittmann
- Institute of Systems Biotechnology, Saarland University, Campus A1.5, 66123, Saarbrücken, Germany.
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Promoting microbial utilization of phenolic substrates from bio-oil. ACTA ACUST UNITED AC 2019; 46:1531-1545. [DOI: 10.1007/s10295-019-02208-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 06/21/2019] [Indexed: 10/26/2022]
Abstract
Abstract
The economic viability of the biorefinery concept is limited by the valorization of lignin. One possible method of lignin valorization is biological upgrading with aromatic-catabolic microbes. In conjunction, lignin monomers can be produced by fast pyrolysis and fractionation. However, biological upgrading of these lignin monomers is limited by low water solubility. Here, we address the problem of low water solubility with an emulsifier blend containing approximately 70 wt% Tween® 20 and 30 wt% Span® 80. Pseudomonas putida KT2440 grew to an optical density (OD600) of 1.0 ± 0.2 when supplied with 1.6 wt% emulsified phenolic monomer-rich product produced by fast pyrolysis of red oak using an emulsifier dose of 0.076 ± 0.002 g emulsifier blend per g of phenolic monomer-rich product. This approach partially mitigated the toxicity of the model phenolic monomer p-coumarate to the microbe, but not benzoate or vanillin. This study provides a proof of concept that processing of biomass-derived phenolics to increase aqueous availability can enhance microbial utilization.
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Song B, Tang J, Zhen M, Liu X. Effect of rhamnolipids on enhanced anaerobic degradation of petroleum hydrocarbons in nitrate and sulfate sediments. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 678:438-447. [PMID: 31077922 DOI: 10.1016/j.scitotenv.2019.04.383] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Revised: 04/20/2019] [Accepted: 04/26/2019] [Indexed: 06/09/2023]
Abstract
Anaerobic degradation of petroleum hydrocarbons (PH) is an important process in contaminated environment. The application of rhamnolipids in anaerobic degradation of PH was not extensively studied and inconclusive. This study explored the combined effect of rhamnolipids and electron acceptors on the anaerobic degradation process of total petroleum hydrocarbons (TPH) in sediment from an oil field. The results indicated that rhamnolipids decreased the surface tension of the medium and increased the desorption of TPH from the sediment. After 10-wk culture, the maximum degradation rate of TPH in nitrate and sulfate condition was found to be 32.2% and 24.0%, respectively, with rhamnolipids concentration of 150 mg/L. The addition of 45 and 150 mg/L rhamnolipids increased the degradation rate of TPH but the promotion effect was weakened in the treatment with 450 mg/L rhamnolipids. The copy number of two degradation genes (1-methylalkyl) succinate synthase gene (masD) and 6-oxocyclohex-1-ene-1-carbonyl-CoA hydrolase gene (bamA) increased with incubation time and showed higher copy numbers in treatments with 45 and 150 mg/L rhamnolipids. In the first week, with the increase of rhamnolipids concentration, the copy number of 16S rDNA increased rapidly and the concentration of electron receptors decreased correspondingly. Moreover, no nitrate was detected in treatments of nitrate with 450 mg/L rhamnolipids after the first week. Microbial community structure analysis result showed that Thiobacillus was the dominant bacteria in all treatments with nitrate as electron acceptor and its proportion gradually decreased with the increase of rhamnolipids concentration. The addition of rhamnolipids changed the subdominant bacteria in the treatments with nitrate as electron acceptor. Methanothrix was the dominant archaea in all treatments with rhamnolipids content of lower than 45 mg/L. When the rhamnolipids concentration increased, the dominant archaea changed to Methanogenium or Methanobacterium. In conclusion, suitable concentrations of rhamnolipids could promote the anaerobic degradation of PH in the sediment.
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Affiliation(s)
- Benru Song
- Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education, Tianjin Engineering Center of Environmental Diagnosis and Contamination Remediation, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China
| | - Jingchun Tang
- Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education, Tianjin Engineering Center of Environmental Diagnosis and Contamination Remediation, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China.
| | - Meinan Zhen
- Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education, Tianjin Engineering Center of Environmental Diagnosis and Contamination Remediation, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China
| | - Xiaomei Liu
- Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education, Tianjin Engineering Center of Environmental Diagnosis and Contamination Remediation, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China
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Adaptive Responses of Shewanella decolorationis to Toxic Organic Extracellular Electron Acceptor Azo Dyes in Anaerobic Respiration. Appl Environ Microbiol 2019; 85:AEM.00550-19. [PMID: 31175185 DOI: 10.1128/aem.00550-19] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 05/29/2019] [Indexed: 12/18/2022] Open
Abstract
Bacterial anaerobic respiration using an extracellular electron acceptor plays a predominant role in global biogeochemical cycles. However, the mechanisms of bacterial adaptation to the toxic organic pollutant as the extracellular electron acceptor during anaerobic respiration are not clear, which limits our ability to optimize the strategies for the bioremediation of a contaminated environment. Here, we report the physiological characteristics and the global gene expression of an ecologically successful bacterium, Shewanella decolorationis S12, when using a typical toxic organic pollutant, amaranth, as the extracellular electron acceptor. Our results revealed that filamentous shift (the cells stretched to fiber-like shapes as long as 18 μm) occurred under amaranth stress. Persistent stress led to a higher filamentous cell rate and decolorization ability in subcultural cells compared to parental strains. In addition, the expression of genes involved in cell division, the chemotaxis system, energy conservation, damage repair, and material transport in filamentous cells was significantly stimulated. The detailed roles of some genes with significantly elevated expressions in filamentous cells, such as the outer membrane porin genes ompA and ompW, the cytochrome c genes arpC and arpD, the global regulatory factor gene rpoS, and the methyl-accepting chemotaxis proteins genes SHD_2793 and SHD_0015, were identified by site-directed mutagenesis. Finally, a conceptual model was proposed to help deepen our insights into both the bacterial survival strategy when toxic organics were present and the mechanisms by which these toxic organics were biodegraded as the extracellular electron acceptors.IMPORTANCE Keeping toxic organic pollutants (TOPs) in tolerable levels is a huge challenge for bacteria in extremely unfavorable environments since TOPs could serve as energy substitutes but also as survival stresses when they are beyond some thresholds. This study focused on the underlying adaptive mechanisms of ecologically successful bacterium Shewanella decolorationis S12 when exposed to amaranth, a typical toxic organic pollutant, as the extracellular electron acceptor. Our results suggest that filamentous shift is a flexible and valid way to solve the dilemma between the energy resource and toxic stress. Filamentous cells regulate gene expression to enhance their degradation and detoxification capabilities, resulting in a strong viability. These novel adaptive responses to TOPs are believed to be an evolutionary achievement to succeed in harsh habitats and thus have great potential to be applied to environment engineering or synthetic biology if we could picture every unknown node in this pathway.
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9
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Influence of graphene oxide and biochar on anaerobic degradation of petroleum hydrocarbons. J Biosci Bioeng 2019; 128:72-79. [DOI: 10.1016/j.jbiosc.2019.01.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 12/17/2018] [Accepted: 01/13/2019] [Indexed: 11/18/2022]
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Mosmeri H, Gholami F, Shavandi M, Dastgheib SMM, Alaie E. Bioremediation of benzene-contaminated groundwater by calcium peroxide (CaO 2) nanoparticles: Continuous-flow and biodiversity studies. JOURNAL OF HAZARDOUS MATERIALS 2019; 371:183-190. [PMID: 30851671 DOI: 10.1016/j.jhazmat.2019.02.071] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Revised: 01/25/2019] [Accepted: 02/20/2019] [Indexed: 06/09/2023]
Abstract
Calcium peroxide (CaO2) nanoparticles have been extensively applied in treatment of contaminated groundwater through bioremediation or modified Fenton (MF) processes. In the present study utilization of CaO2 in bioremediation and MF (CaO2+FeSO4) reaction is investigated for benzene (50 mg/L) removal in continuous flow sand-packed columns. The results indicated that MF produced OH radicals markedly increased benzene remediation at first 30 days (up to 93%). But, OH generation rate was gradually declined when the pH was increased and finally 75% of initial benzene removed after 100d. In bioremediation column, because of supplying adequate oxygen by CaO2, the number of planktonic bacteria logarithmically increased to more than 5 × 106 CFU/mL (two orders of magnitude) and consequently 100% benzene removal was achieved by the end of experiment. Scanning electron microscopy analysis visualized the attached biofilm growth on sand surfaces in CaO2 injected columns indicating their key role in the remediation process. The impact of each process on the microbial biodiversity of groundwater was investigated by next generation sequencing (NGS) of the 16S rRNA gene. The alpha and beta analysis indicated that microbial diversity is decreased by CaO2 injection while benzene-degrading species such as Silanimonas, Arthrobacter and Pseudomonas spp. were dominated in remediation column.
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Affiliation(s)
- Hamid Mosmeri
- Ecology and Environmental Pollution Control Research Group, Research Institute of Petroleum Industry, Tehran, Iran
| | - Fatemeh Gholami
- Department of Microbiology, College of Science, University of Tehran, Tehran, Iran
| | - Mahmoud Shavandi
- Ecology and Environmental Pollution Control Research Group, Research Institute of Petroleum Industry, Tehran, Iran.
| | | | - Ebrahim Alaie
- Environment and Biotechnology Research Division, Research Institute of Petroleum Industry, Tehran, Iran
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Matharu RK, Porwal H, Ciric L, Edirisinghe M. The effect of graphene-poly(methyl methacrylate) fibres on microbial growth. Interface Focus 2018; 8:20170058. [PMID: 29696090 PMCID: PMC5915660 DOI: 10.1098/rsfs.2017.0058] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/31/2018] [Indexed: 11/30/2022] Open
Abstract
A novel class of ultra-thin fibres, which affect microbial growth, were explored. The microbial properties of poly(methyl methacrylate) fibres containing 2, 4 and 8 wt% of graphene nanoplatelets (GNPs) were studied. GNPs were dispersed in a polymeric solution and processed using pressurized gyration. Electron microscopy was used to characterize GNP and fibre morphology. Scanning electron microscopy revealed the formation of beaded porous fibres. GNP concentration was found to dictate fibre morphology. As the GNP concentration increased, the average fibre diameter increased from 0.75 to 2.71 µm, while fibre porosity decreased. Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa were used to investigate the properties of 2, 4 and 8 wt% GNP-loaded fibres. GNP-loaded fibres (0 wt%) were used as the negative control. The fibres were incubated for 24 h with the bacteria; bacterial colony-forming units were enumerated by adopting the colony-counting method. The presence of 2 and 4 wt% GNP-loaded fibres promoted microbial growth, while 8 wt% GNP-loaded fibres showed antimicrobial activity. These results indicate that the minimum inhibitory concentration of GNPs required within a fibre is 8 wt%.
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Affiliation(s)
- Rupy Kaur Matharu
- Department of Mechanical Engineering, University College London, Torrington Place, London WC1E 7JE, UK
- Department of Civil, Environmental & Geomatic Engineering, University College London, Chadwick Building, Gower Street, London WC1E 6BT, UK
| | - Harshit Porwal
- School of Engineering and Materials Science, Queen Mary University of London, Mile End Road, London E1 4NS, UK
| | - Lena Ciric
- Department of Civil, Environmental & Geomatic Engineering, University College London, Chadwick Building, Gower Street, London WC1E 6BT, UK
| | - Mohan Edirisinghe
- Department of Mechanical Engineering, University College London, Torrington Place, London WC1E 7JE, UK
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12
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Martin MS, Santos IC, Carlton DD, Stigler-Granados P, Hildenbrand ZL, Schug KA. Characterization of bacterial diversity in contaminated groundwater using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 622-623:1562-1571. [PMID: 29054663 DOI: 10.1016/j.scitotenv.2017.10.027] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 10/04/2017] [Accepted: 10/04/2017] [Indexed: 06/07/2023]
Abstract
Groundwater is a major source for drinking water in the United States, and therefore, its quality and quantity is of extreme importance. One major concern that has emerged is the possible contamination of groundwater due to the unconventional oil and gas extraction activities. As such, the impacts of exogenous contaminants on microbial ecology is an area to be explored to understand what are the chemical and physical conditions that allow the proliferation of pathogenic bacteria and to find alternatives for water treatment by identifying organic-degrading bacteria. In this work, we assess the interplay between groundwater quality and the microbiome in contaminated groundwaters rich in hydrocarbon gases, volatile organic and inorganic compounds, and various metals. Opportunistic pathogenic bacteria, such as Aeromonas hydrophila, Bacillus cereus, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia, were identified, increasing the risk for consumption of and exposure to these contaminated groundwaters. Additionally, antimicrobial tests revealed that many of the identified bacteria were resistant to different antibiotics. The MALDI-TOF MS results were successfully confirmed with 16S rRNA gene sequencing, proving the accuracy of this high-throughput method. Collectively, these data provide a seminal understanding of the microbial populations in contaminated groundwater overlying anthropogenic activities like unconventional oil and gas development.
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Affiliation(s)
- Misty S Martin
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX, USA
| | - Inês C Santos
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX, USA; Collaborative Laboratories for Environmental Analysis and Remediation, The University of Texas at Arlington, Arlington, TX, USA
| | - Doug D Carlton
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX, USA; Collaborative Laboratories for Environmental Analysis and Remediation, The University of Texas at Arlington, Arlington, TX, USA
| | | | - Zacariah L Hildenbrand
- Collaborative Laboratories for Environmental Analysis and Remediation, The University of Texas at Arlington, Arlington, TX, USA; Inform Environmental, LLC, Dallas, TX, USA.
| | - Kevin A Schug
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX, USA; Collaborative Laboratories for Environmental Analysis and Remediation, The University of Texas at Arlington, Arlington, TX, USA.
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14
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Fijten RRR, Smolinska A, Shi Q, Pachen DM, Dallinga JW, Boots AW, van Schooten FJ. Exposure to genotoxic compounds alters in vitro cellular VOC excretion. J Breath Res 2018; 12:027101. [PMID: 28972195 DOI: 10.1088/1752-7163/aa9080] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Genotoxic carcinogens significantly damage cells and tissues by targeting macromolecules such as proteins and DNA, but their mechanisms of action and effects on human health are diverse. Consequently, determining the amount of exposure to a carcinogen and its cellular effects is essential, yet difficult. The aim of this manuscript was to investigate the potential of detecting alterations in volatile organic compounds (VOCs) profiles in the in vitro headspace of pulmonary cells after exposure to the genotoxic carcinogens cisplatin and benzo[a]pyrene using two different sampling set-ups. A prototype set-up was used for the cisplatin exposure, whereas a modified set-up was utilized for the benzo[a]pyrene exposure. Both carcinogens were added to the cell medium for 24 h. The headspace in the culture flask was sampled to measure the VOC content using gas chromatography-time-of-flight-mass spectrometry. Eight cisplatin-specific VOCs and six benzo[a]pyrene-specific VOCs were discriminatory between treated and non-treated cells. Since the in vivo biological effects of both genotoxic compounds are well-defined, the origin of the identified VOCs could potentially be traced back to common cellular processes including cell cycle pathways, DNA damage and repair. These results indicate that exposing lung cells to genotoxins alters headspace VOC profiles, suggesting that it might be possible to monitor VOC changes in vivo to study drug efficacy or exposure to different pollutants. In conclusion, this study emphasizes the innovative potential of in vitro VOCs experiments to determine their in vivo applicability and discover their endogenous origin.
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Affiliation(s)
- R R R Fijten
- Department of Pharmacology & Toxicology, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, The Netherlands
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Padhi SK, Gokhale S. Treatment of gaseous volatile organic compounds using a rotating biological filter. BIORESOURCE TECHNOLOGY 2017; 244:270-280. [PMID: 28780260 DOI: 10.1016/j.biortech.2017.07.112] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 07/15/2017] [Accepted: 07/21/2017] [Indexed: 06/07/2023]
Abstract
Rotating biological filter (RBF), which provides higher oxygen mass transfer has been developed for treating gaseous volatile organic compounds (VOCs) such as BTEX (Benzene, toluene, ethylbenzene and xylene) at higher concentrations. The screening of enriched cultures has been done initially to enhance the performance of RBF for treating xylene, toluene and xylene, and BTEX at various loading rates. The removal efficiency of BTEX was maximum (82%), higher than toluene and xylene (79%), and xylene (72%). The presence of xylene enhanced the removal of toluene in the mixture. In the BTEX, toluene was found to be highly biodegradable followed by ethylbenzene, benzene and xylene. The RBF also removed nutrients from wastewater along with VOCs. The stability study of RBF showed that supply of nutrient media influenced the RBF performance more. Further, the predominant strain identified in the mixed culture was Enterobacter cloacae SP4001, responsible for biodegradation of BTEX.
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Affiliation(s)
- Susant Kumar Padhi
- Department of Civil Engineering, Indian Institute of Technology Guwahati, Guwahati 781039, India
| | - Sharad Gokhale
- Department of Civil Engineering, Indian Institute of Technology Guwahati, Guwahati 781039, India.
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16
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Kureel MK, Geed SR, Giri BS, Rai BN, Singh RS. Biodegradation and kinetic study of benzene in bioreactor packed with PUF and alginate beads and immobilized with Bacillus sp. M3. BIORESOURCE TECHNOLOGY 2017; 242:92-100. [PMID: 28390787 DOI: 10.1016/j.biortech.2017.03.167] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2017] [Revised: 03/25/2017] [Accepted: 03/27/2017] [Indexed: 05/23/2023]
Abstract
Benzene removal in free and immobilized cells on polyurethane foam (PUF) and polyvinyl alcohol (PVA)-alginate beads was studied using an indigenous soil bacterium Bacillus sp. M3 isolated from petroleum-contaminated soil. The important process parameters (pH, temperature and inoculums size) were optimized and found to be 7, 37°C and 6.0×108CFU/mL, respectively. Benzene removals were observed to be 70, 84 and 90% within 9days in a free cell, immobilized PVA-alginate beads and PUF, respectively under optimum operating conditions. FT-IR and GC-MS analysis confirm the presence of phenol, 1,2-benzenediol, hydroquinone and benzoate as metabolites. The important kinetic parameter ratios (µmax/Ks; L/mg·day) calculated using Monod model was found to be 0.00123 for free cell, 0.00159 for immobilized alginate beads and 0.002016 for immobilized PUF. Similarly inhibition constants (Ki; mg/L) calculated using Andrew-Haldane model was found to be 435.84 for free cell, 664.25 for immobilized alginate beads and 724.93 for immobilized PUF.
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Affiliation(s)
- M K Kureel
- Department of Chemical Engineering & Technology, IIT (BHU), Varanasi, UP 221005, India
| | - S R Geed
- Department of Chemical Engineering & Technology, IIT (BHU), Varanasi, UP 221005, India
| | - B S Giri
- Department of Chemical Engineering & Technology, IIT (BHU), Varanasi, UP 221005, India
| | - B N Rai
- Department of Chemical Engineering & Technology, IIT (BHU), Varanasi, UP 221005, India
| | - R S Singh
- Department of Chemical Engineering & Technology, IIT (BHU), Varanasi, UP 221005, India.
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Zhou Y, Huang H, Shen D. Multi-substrate biodegradation interaction of 1, 4-dioxane and BTEX mixtures by Acinetobacter baumannii DD1. Biodegradation 2016; 27:37-46. [PMID: 26749222 DOI: 10.1007/s10532-015-9753-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 12/22/2015] [Indexed: 10/22/2022]
Abstract
This study evaluated substrate interactions during the aerobic biodegradation of 1, 4-dioxane and BTEX mixtures by a pure culture, Acinetobacter baumannii DD1, which is capable of utilizing 1, 4-dioxane for growth. A. baumannii DD1 could utilize BTEX as a sole carbon source, but could not utilize m-xylene and p-xylene. In binary mixtures, there was a lag of about 14 h before the degradation of BTE, and 1, 4-dioxane only started to be utilized when BTE was completely degraded by 1, 4-dioxane-grown DD1. Furthermore, the biodegradation rate of 1, 4-dioxane decreased from 73.33 to 40.74 mg/(h g dry weight) after the biodegradation of benzene. 1, 4-dioxane could not be degraded after the biodegradation of o-xylene in 80 h. DD1 could also not degrade m-xylene and p-xylene coexisting with 1, 4-dioxane. The ability of DD1 to degrade BTEX occurred in the following order: benzene > ethylbenzene > toluene > o-xylene > m-xylene = p-xylene. The biodegradation of 1, 4-dioxane was not activated in the mixture with o-xylene, primarily because of the accumulation of the specific toxic intermediate, 2, 3-dimethylphenol. The lag in BTE degradation was presumably because of the induction of enzymes necessary for BTE degradation. Additionally, SDS-PAGE analysis demonstrated that there were different proteins during the degradation of benzene and 1, 4-dioxane.
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Affiliation(s)
- YuYang Zhou
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, 310012, China.,Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Zhejiang Gongshang University, Hangzhou, 310012, China
| | - Huanlin Huang
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, 310012, China.,Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Zhejiang Gongshang University, Hangzhou, 310012, China
| | - Dongsheng Shen
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, 310012, China. .,Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Zhejiang Gongshang University, Hangzhou, 310012, China.
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Ndlovu T, Ward A, Glassey J, Eskildsen J, Akay G. Bioprocess intensification of antibiotic production by Streptomyces coelicolor A3(2) in micro-porous culture. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2015; 49:799-806. [DOI: 10.1016/j.msec.2015.01.052] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 12/07/2014] [Accepted: 01/14/2015] [Indexed: 10/24/2022]
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Long H, Sung W, Miller SF, Ackerman MS, Doak TG, Lynch M. Mutation rate, spectrum, topology, and context-dependency in the DNA mismatch repair-deficient Pseudomonas fluorescens ATCC948. Genome Biol Evol 2014; 7:262-71. [PMID: 25539726 PMCID: PMC4316635 DOI: 10.1093/gbe/evu284] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
High levels of genetic diversity exist among natural isolates of the bacterium Pseudomonas fluorescens, and are especially elevated around the replication terminus of the genome, where strain-specific genes are found. In an effort to understand the role of genetic variation in the evolution of Pseudomonas, we analyzed 31,106 base substitutions from 45 mutation accumulation lines of P. fluorescens ATCC948, naturally deficient for mismatch repair, yielding a base-substitution mutation rate of 2.34 × 10−8 per site per generation (SE: 0.01 × 10−8) and a small-insertion-deletion mutation rate of 1.65 × 10−9 per site per generation (SE: 0.03 × 10−9). We find that the spectrum of mutations in prophage regions, which often contain virulence factors and antibiotic resistance, is highly similar to that in the intergenic regions of the host genome. Our results show that the mutation rate varies around the chromosome, with the lowest mutation rate found near the origin of replication. Consistent with observations from other studies, we find that site-specific mutation rates are heavily influenced by the immediately flanking nucleotides, indicating that mutations are context dependent.
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Affiliation(s)
- Hongan Long
- Department of Biology, Indiana University, Bloomington
| | - Way Sung
- Department of Biology, Indiana University, Bloomington
| | | | | | - Thomas G Doak
- Department of Biology, Indiana University, Bloomington National Center for Genome Analysis Support, Indiana University, Bloomington
| | - Michael Lynch
- Department of Biology, Indiana University, Bloomington
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Growth kinetics of an indigenous mixed microbial consortium during methylene chloride degradation in a batch reactor. KOREAN J CHEM ENG 2013. [DOI: 10.1007/s11814-013-0099-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Degradation of benzene, toluene, and xylene (BTX) from aqueous solution by isolated bacteria from contaminated sites. RESEARCH ON CHEMICAL INTERMEDIATES 2013. [DOI: 10.1007/s11164-013-1189-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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22
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Gharibzahedi SMT, Razavi SH, Mousavi M. Kinetic analysis and mathematical modeling of cell growth and canthaxanthin biosynthesis by Dietzia natronolimnaea HS-1 on waste molasses hydrolysate. RSC Adv 2013. [DOI: 10.1039/c3ra44663h] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Song J, Namgung H, Ahmed Z. Biodegradation of toluene using Candida tropicalis immobilized on polymer matrices in fluidized bed bioreactors. JOURNAL OF HAZARDOUS MATERIALS 2012; 241-242:316-322. [PMID: 23069330 DOI: 10.1016/j.jhazmat.2012.09.049] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Revised: 09/17/2012] [Accepted: 09/20/2012] [Indexed: 06/01/2023]
Abstract
A yeast strain, Candida tropicalis, was whole-cell-immobilized on polymer matrices of polyethylene glycol (PEG) and polyethylene glycol/activated carbon/alginate (PACA). The polymer matrices were used as fluidized materials in bubble-column bioreactors for the biodegradation of toluene. Simultaneously, another bubble-column bioreactor using granular activated carbon (GAC) and a conventional compost biofilter were operated for comparison. In the compost biofilter, the toluene removal efficiency gradually deteriorated due to the limitation of microbial activity. The toluene removal in the GAC bioreactor was relatively high because of an increase of toluene mass transfer. However, low toluene removal efficiencies were observed in the PEG bioreactor, presumably because the synthetic polymer alone was not suitable for yeast cell immobilization. In the PACA bioreactor, toluene removal was found to be greater than 95% overall. The CO(2) yield coefficient calculated at the highest toluene loading condition for the PACA bioreactor was found to be higher than those observed in the other bioreactors. Furthermore, almost complete elimination capacities were observed in the PACA bioreactor at short-term toluene loading up to 180 g/m(3)/h. In conclusion, the immobilization of C. tropicalis in the PACA matrix resulted in enhanced toluene biodegradation because of the increases of both mass transfer and microbial activity.
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Affiliation(s)
- JiHyeon Song
- Department of Civil and Environmental Engineering, Sejong University, Kwangjin-gu, Seoul, 143-747, South Korea
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Okunishi S, Morita Y, Higuchi T, Maeda H, Nishi K. Transformation of microflora during degradation of gaseous toluene in a biofilter detected using PCR-DGGE. JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION (1995) 2012; 62:748-757. [PMID: 22866576 DOI: 10.1080/10962247.2012.672396] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A laboratory-scale biofiltration system, the rotatory-switching biofilter (RSB), was operated for 199 days using toluene as a model pollutant. The target gaseous pollutant for the biofiltration experiment was approximately 300 ppmv of toluene. Toluene removal efficiency (RE, %) was initially approximately 20% with a 247-ppmv concentration (0.9 g m(-3)) of toluene during the first 10 days. Although the RE decreased several times whenever nitrogen was consumed, it again reached almost 100% when the nitrogen source was in sufficient supply. Denaturing gradient gel electrophoresis (DGGE) analysis was employed to assess the transformation ofmicroflora during operation of the biofilter The results based on a 16S rRNA gene profile showed that the microbial community structure changed with operation time. Although the microflora changed during the initial period (before day 40), transformation of the bacterial component was hardly observed after day 51. Statistical analyses of the DGGE profiles indicated that the bacterial community was almost unaffected by the environmental factors, such as adding ozone, high-level nitrogen supply, increase of loading toluene, and the shutdown of the RSB. The DGGE profile using tmoA-like genes, which encode proteins belonging to the hydroxylase component mono-oxygenases involved in the initial attack of aerobic benzene, toluene, ethylbenzene, and xylene degradation, confirmed the existence of toluene-degrading bacteria. There were at least four kinds of toluene-degradable bacteria having tmoA-like genes up to day 36, which decreased to two species after day 40. Sequence analysis after DGGE profiling revealed that Burkholderia cepacia, Sphingobacterium multivorum, and Pseudomonas putida were present in the biofilter. Only Alicycliphilus denitrificans was present throughout the whole operation period. In the initial stage of operating the RSB, many types of bacteria may have tried to adapt to the conditions, and subsequently, only selected bacteria were able to grow and to degrade toluene.
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Affiliation(s)
- Suguru Okunishi
- Faculty of Medicine, Shiga University of Medical Science, Otsu, Japan
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Ahmed Z, Song J. Removal of gaseous toluene using immobilized Candida tropicalis in a fluidized bed bioreactor. 3 Biotech 2011; 1:111-116. [PMID: 22582151 PMCID: PMC3339623 DOI: 10.1007/s13205-011-0015-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2011] [Accepted: 06/29/2011] [Indexed: 11/26/2022] Open
Abstract
A pure yeast strain Candida tropicalis was immobilized on the matrix of powdered activated carbon, sodium alginate, and polyethylene glycol (PSP beads). The immobilized beads were used as fluidized material in a bioreactor to remove toluene from gaseous stream. Applied toluene loadings were 15.4 and 29.8 g/m3 h in Step 1 and Step 2, respectively, and toluene removal was found above 95% during the entire operation. A continuous pH decline was observed and pH of the suspension was just above 6 in Step 2 but no adverse effects on treatment efficiency were observed. The CO2 yield values were found to be 0.57 and 0.62 g- in Step 1 and Step 2, respectively. These values indicate that a major portion of toluene-carbon was channeled to yeast respiration even at higher toluene loading. In conclusion, immobilized C. tropicalis can be used as a fluidized material for enhanced degradation of gaseous toluene.
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Affiliation(s)
- Zubair Ahmed
- Department of Civil Engineering, Faculty of Engineering, King Abdulaziz University, P.O. Box 80204, Jeddah, 21589 Kingdom of Saudi Arabia
| | - JiHyeon Song
- Department of Civil and Environmental Engineering, Sejong University, Kwangjin-gu, Seoul, 143-747 Republic of Korea
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Aburto A, Peimbert M. Degradation of a benzene-toluene mixture by hydrocarbon-adapted bacterial communities. ANN MICROBIOL 2010; 61:553-562. [PMID: 21949494 PMCID: PMC3156334 DOI: 10.1007/s13213-010-0173-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2010] [Accepted: 11/23/2010] [Indexed: 11/30/2022] Open
Abstract
We examined the rate of degradation of a benzene–toluene mixture in aerobic microcosms prepared with samples of an aquifer that lies below a petrochemical plant (SIReN, UK). Five samples exposed to different concentrations of benzene (from 0.6 to 317 mg l−1) were used. Fast degradation (approx. 1–6 mg l−1 day−1) of both contaminants was observed in all groundwater samples and complete degradation was recorded by the seventh day except for one sample. We also identified the microbial community in each of the samples by culture-independent techniques. Two of the less impacted samples harbour the aerobic benzene degrader Pseudomonas fluorescens, while Acidovorax and Arthrobacter spp. were found in the most polluted sample and are consistent with the population observed in situ. Hydrogenophaga was found in the deepest sample while Rhodoferax spp. were recovered in an alkaline sample (pH 8.4) and may also be implicated in benzene degradation. Time series analysis shows that each of the samples has a different community but they remain stable over the degradation period. This study provides new information on a well not previously studied (no. 309s) and confirms that adapted communities have the ability to degrade hydrocarbon mixtures and could be used in further bioaugmentation approaches in contaminated sites.
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Affiliation(s)
- Arturo Aburto
- Department of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ UK
- Present Address: School of Biological Sciences, University of California, Irvine, USA
| | - Mariana Peimbert
- Department of Natural Sciences, Universidad Autónoma Metropolitana Cuajimalpa, Artificios 40, 01120 México City, México
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Trigueros DE, Módenes AN, Kroumov AD, Espinoza-Quiñones FR. Modeling of biodegradation process of BTEX compounds: Kinetic parameters estimation by using Particle Swarm Global Optimizer. Process Biochem 2010. [DOI: 10.1016/j.procbio.2010.05.007] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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28
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de Souza SMDAGU, Bonilla KAS, de Souza AAU. Removal of COD and color from hydrolyzed textile azo dye by combined ozonation and biological treatment. JOURNAL OF HAZARDOUS MATERIALS 2010; 179:35-42. [PMID: 20227826 DOI: 10.1016/j.jhazmat.2010.02.053] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2009] [Revised: 02/11/2010] [Accepted: 02/16/2010] [Indexed: 05/15/2023]
Abstract
The application of ozonation has been increasing in recent years, the main disadvantage of this type of treatment being related to the by-products, which can have toxic and carcinogenic properties, and therefore should be studied further. In this study, the combined treatment of ozonation and subsequent biological degradation with a biofilm, to reduce the color and chemical oxygen demand (COD), was investigated. The experimental part of the study consisted of two phases. The first phase was the ozonation process, the results obtained demonstrated that the ozonation of Remazol Black B dye at pH values of 3-11, was effective, partially oxidizing and completely decolorizing the effluent, even at relatively high concentrations of the dye (500 mg/L). Color removal efficiencies greater than 96% were obtained in all cases. The degradation kinetics of ozone is a pseudo-first-order reaction with respect to the dye concentration. It was possible to verify that the ozonation process as a pre-treatment increases the dye degradation efficiency. For the biological treatment, an increase in ozonization time increased the dye concentration reduction in hydrolyzed dye synthetic effluent. The toxicological results of the tests with Daphnia Magna showed that there is an increase in toxicity after ozonization and a decrease after submitting the ozonized synthetic wastewater to biological treatment with a biofilm.
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Yan T, Long J, Shi X, Wang D, Li Z, Wang X. Efficient photocatalytic degradation of volatile organic compounds by porous indium hydroxide nanocrystals. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2010; 44:1380-1385. [PMID: 20085263 DOI: 10.1021/es902702v] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Nanosized porous In(OH)(3) photocatalysts with high surface areas (as much as 110 m(2)*g(-1)) were successfully synthesized by peptization of colloidal precipitates under ultrasound radiation. The resulting catalysts were characterized by X-ray powder diffraction (XRD), thermogravimetric analysis, nitrogen adsorption, transition electron microscopy, and UV-vis diffuse reflection spectroscopy. The photocatalytic activities of the samples were evaluated by the gas-phase decomposition of several volatile organic pollutants (acetone, benzene, and toluene) under UV light illumination and were compared with that of the commercial titania (Degussa P25). Results revealed that the as-synthesized In(OH)(3) exhibited much higher photocatalytic activity and durability than both In(2)O(3) and TiO(2). One, therefore, can conclude that nanosized In(OH)(3) has potential application in environmental treatment, especially in the removal of benzene-containing exhaust emissions from shoemaking plants in China. The excellent photocatalytic performance of In(OH)(3) can be attributed to its strong oxidation capability, abundant surface hydroxyl groups, and high BET surface area as well as the porous texture.
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Affiliation(s)
- Tingjiang Yan
- State Key Laboratory Breeding Base of Photocatalysis, Research Institute of Photocatalysis, Fuzhou University, Fuzhou 350002, People's Republic of China
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Robledo-Ortíz JR, Ramírez-Arreola DE, Gomez C, González-Reynoso O, González-Núñez R. Bacterial immobilization by adhesion onto agave-fiber/polymer foamed composites. BIORESOURCE TECHNOLOGY 2010; 101:1293-1299. [PMID: 19819131 DOI: 10.1016/j.biortech.2009.09.058] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2008] [Revised: 09/15/2009] [Accepted: 09/15/2009] [Indexed: 05/28/2023]
Abstract
Adhesion of Pseudomonas putida F1 onto agave-fiber/recycled-polyethylene foamed composites was studied under different controlled conditions. The adhesion process was analyzed in batch experiments controlling factors such as pH, contact time, temperature, initial biomass concentration and ionic strength; and was verified by scanning electron microscopy (SEM). The number of adhered bacteria after the experimental time was determined by difference between concentration of suspended cells in NaCl solution contained in two different Erlenmeyer flasks, one of the flasks with composite pellets and the other one without them. The concentration of cells in each flask was obtained using the serial dilution technique. Experimental data analysis showed that adsorption follows first-order kinetics. And it was further corroborated to be an irreversible process. For the first time, an equation is proposed here to predict the correlation between adhered bacteria and aqueous pH. In addition to the obvious reuse of waste material, these results suggested that agave-fiber/polymer foamed composites could be used as support for bacterial immobilization to be applied, among others in environmental processes such as bioremediation and biofiltration of gases with almost limitless possibilities.
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Affiliation(s)
- J R Robledo-Ortíz
- Departamento de Ingeniería Química, Universidad de Guadalajara, Blvd. Gral. Marcelino García Barragán # 1451, Guadalajara, Jalisco, C.P. 44430, Mexico
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Darracq G, Couvert A, Couriol C, Amrane A, Le Cloirec P. Integrated process for hydrophobic VOC treatment-solvent choice. CAN J CHEM ENG 2010. [DOI: 10.1002/cjce.20325] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Huang J, Ding K, Wang X, Fu X. Nanostructuring cadmium germanate catalysts for photocatalytic oxidation of benzene at ambient conditions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:8313-8319. [PMID: 19594191 DOI: 10.1021/la9005345] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A nanostructured Cd(2)Ge(2)O(6) photocatalyst was successfully prepared by a hydrothermal process. The photocatalyst was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV/vis, N(2) adsorption-desorption, and Fourier transform infrared (FTIR) techniques. The photocatalytic property of the material was evaluated via the decomposition of benzene in the gas phase with light illumination and was compared with that of commercial titania (Degussa P25) and Pt/TiO(2). The electronic band structure of Cd(2)Ge(2)O(6) was analyzed by density functional theory (DFT) calculation. Results reveal that the prepared Cd(2)Ge(2)O(6) has unique geometric and electronic properties, which in combination with its superior textural properties makes it a new semiconductor photocatalyst for environmental purification of benzene in air with molecular oxygen under ambient conditions. It was also found that the Cd(2)Ge(2)O(6) was more active and stable than TiO(2)-based catalysts in the photocatalytic decomposition of other volatile aromatic pollutants including toluene and ethylbenzene. The enhanced photocatalytic performance of Cd(2)Ge(2)O(6) can be explained by the special band structure, and geometric and electronic feature, in unison with the high surface area nanoporous framework.
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Affiliation(s)
- Jianhui Huang
- Research Institute of Photocatalysis, Fuzhou University, Fuzhou 350002, People's Republic of China
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Chen HL, Yao J, Wang L, Wang F, Bramanti E, Maskow T, Zaray G. Evaluation of solvent tolerance of microorganisms by microcalorimetry. CHEMOSPHERE 2009; 74:1407-1411. [PMID: 19084259 DOI: 10.1016/j.chemosphere.2008.11.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2008] [Revised: 10/31/2008] [Accepted: 11/03/2008] [Indexed: 05/27/2023]
Abstract
Solvent tolerance is important because it allows microorganisms to grow at high concentrations of organic solvents. Organisms capable of surviving under these extreme conditions have great application in bioremediation of contaminated sites. In our study, four strains of Pseudomonas sp. B1 and J2, Acinetobacter sp. B2 and J6 which were isolated from the activated sludge were used to evaluate the solvent tolerance by microcalorimetry. The strains B2 and J2 showed high tolerance to organic solvent as they could grow well in the medium containing 10 vol% of benzene and 70 vol% of toluene, respectively. The higher the growth rate constant, the higher the solvent tolerance of the strains isolated. The microbial growths obtained by microcalorimetry were in good agreement with the results determined by OD(600). The decrease in growth rate constant and the change in total thermal effect in the presence of organic solvents were in agreement with the data reported in the literatures. Strains B1 and B2 degraded about 67% and 94% of 0.1 vol% benzene within 72 h in a medium with benzene as the sole carbon source, respectively. Strains J2 and J6 degraded approximately 92% and 85% of 0.1 vol% toluene within 72 h, respectively. The related degradation genes detected in previous study in these strains highlight an important potential use of those bacteria for the clean-up of benzene and toluene in the environment.
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Affiliation(s)
- Hui-Lun Chen
- Key Laboratory of Biogeology and Environmental Geology, Chinese Ministry of Education, China University of Geosciences, Wuhan, PR China
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35
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Pirôllo M, Mariano A, Lovaglio R, Costa S, Walter V, Hausmann R, Contiero J. Biosurfactant synthesis byPseudomonas aeruginosaLBI isolated from a hydrocarbon-contaminated site. J Appl Microbiol 2008; 105:1484-90. [DOI: 10.1111/j.1365-2672.2008.03893.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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36
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Jean JS, Lee MK, Wang SM, Chattopadhyay P, Maity JP. Effects of inorganic nutrient levels on the biodegradation of benzene, toluene, and xylene (BTX) by Pseudomonas spp. in a laboratory porous media sand aquifer model. BIORESOURCE TECHNOLOGY 2008; 99:7807-7815. [PMID: 18329875 DOI: 10.1016/j.biortech.2008.01.064] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2007] [Revised: 01/17/2008] [Accepted: 01/20/2008] [Indexed: 05/26/2023]
Abstract
The effect of inorganic nutrients (sulfate, phosphate, and ammonium chloride) on the aerobic biodegradation of benzene, toluene, and xylene (BTX) by Pseudomonas spp. was studied in the laboratory using a glass sand tank. The increase of nutrient levels resulted in enhanced bacterial growth and BTX degradation. Sulfate and phosphate serve as key electron acceptors in the microbiological processes degrading BTX. The observed bacterial morphological changes during BTX degradation reveal that the filamentous bacteria were the dominant species at low temperatures about 20 degrees C. The spherical and rod-shaped cells became dominant at higher temperatures ranging from 25 degrees C to 28 degrees C. When the BTX mixture was allowed to be biodegraded for longer incubation periods of 21-42 h at high phosphate concentrations, large amounts of rod-shaped cells were clustered. The morphological adaptation appears to be controlled by the temperature and nutrient levels in the sandy medium where Pseudomonas spp. thrives.
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Affiliation(s)
- Jiin-Shuh Jean
- Department of Earth Sciences, National Cheng Kung University, Tainan City 70101, Taiwan.
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37
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Pagliaccia D, Merhaut D, Colao MC, Ruzzi M, Saccardo F, Stanghellini ME. Selective enhancement of the fluorescent pseudomonad population after amending the recirculating nutrient solution of hydroponically grown plants with a nitrogen stabilizer. MICROBIAL ECOLOGY 2008; 56:538-554. [PMID: 18347844 DOI: 10.1007/s00248-008-9373-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2007] [Revised: 01/11/2008] [Accepted: 02/05/2008] [Indexed: 05/26/2023]
Abstract
Fluorescent pseudomonads have been associated, via diverse mechanisms, with suppression of root disease caused by numerous fungal and fungal-like pathogens. However, inconsistent performance in disease abatement, after their employment, has been a problem. This has been attributed, in part, to the inability of the biocontrol bacterium to maintain a critical threshold population necessary for sustained biocontrol activity. Our results indicate that a nitrogen stabilizer (N-Serve, Dow Agrosciences) selectively and significantly enhanced, by two to three orders of magnitude, the resident population of fluorescent pseudomonads in the amended (i.e., 25 microg ml(-1) nitrapyrin, the active ingredient) and recycled nutrient solution used in the cultivation of hydroponically grown gerbera and pepper plants. Pseudomonas putida was confirmed as the predominant bacterium selectively enhanced. Terminal restriction fragment length polymorphism (T-RFLP) analysis of 16S rDNA suggested that N-Serve selectively increased P. putida and reduced bacterial diversity 72 h after application. In vitro tests revealed that the observed population increases of fluorescent pseudomonads were preceded by an early growth suppression of indigenous aerobic heterotrophic bacteria (AHB) population. Interestingly, the fluorescent pseudomonad population did not undergo this decrease, as shown in competition assays. Xylene and 1,2,4-trimethylbenzene (i.e., the inert ingredients in N-Serve) were responsible for a significant percentage of the fluorescent pseudomonad population increase. Furthermore, those increases were significantly higher when the active ingredient (i.e., nitrapyrin) and the inert ingredients were combined, which suggests a synergistic response. P. putida strains were screened for the ability to produce antifungal compounds and for the antifungal activity against Pythium aphanidermatum and Phytophthora capsici. The results of this study suggest the presence of diverse mechanisms with disease-suppressing potential. This study demonstrates the possibility of using a specific substrate to selectively enhance and maintain desired populations of a natural-occurring bacterium such as P. putida, a trait considered to have great potential in biocontrol applications for plant protection.
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Affiliation(s)
- D Pagliaccia
- Department of Plant Production, University of Tuscia, 01100, Viterbo, Italy.
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38
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Farhadian M, Vachelard C, Duchez D, Larroche C. In situ bioremediation of monoaromatic pollutants in groundwater: a review. BIORESOURCE TECHNOLOGY 2008; 99:5296-5308. [PMID: 18054222 DOI: 10.1016/j.biortech.2007.10.025] [Citation(s) in RCA: 166] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2007] [Revised: 10/15/2007] [Accepted: 10/16/2007] [Indexed: 05/25/2023]
Abstract
Monoaromatic pollutants such as benzene, toluene, ethylbenzene and mixture of xylenes are now considered as widespread contaminants of groundwater. In situ bioremediation under natural attenuation or enhanced remediation has been successfully used for removal of organic pollutants, including monoaromatic compounds, from groundwater. Results published indicate that in some sites, intrinsic bioremediation can reduce the monoaromatic compounds content of contaminated water to reach standard levels of potable water. However, engineering bioremediation is faster and more efficient. Also, studies have shown that enhanced anaerobic bioremediation can be applied for many BTEX contaminated groundwaters, as it is simple, applicable and economical. This paper reviews microbiology and metabolism of monoaromatic biodegradation and in situ bioremediation for BTEX removal from groundwater under aerobic and anaerobic conditions. It also discusses the factors affecting and limiting bioremediation processes and interactions between monoaromatic pollutants and other compounds during the remediation processes.
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Affiliation(s)
- Mehrdad Farhadian
- LGCB, Polytech'Clermont-Ferrand, Université Blaise Pascal, Clermont-Ferrand, France
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39
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Effects of cell entrapment on growth rate and metabolic activity of mixed cultures in biological wastewater treatment. Enzyme Microb Technol 2008. [DOI: 10.1016/j.enzmictec.2008.04.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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40
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Cápiro NL, Da Silva MLB, Stafford BP, Rixey WG, Alvarez PJJ. Microbial community response to a release of neat ethanol onto residual hydrocarbons in a pilot-scale aquifer tank. Environ Microbiol 2008; 10:2236-44. [PMID: 18484998 DOI: 10.1111/j.1462-2920.2008.01645.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Natalie L Cápiro
- Department of Civil and Environmental Engineering, Rice University, 6100 Main Street - MS 317, Houston, TX 77005, USA.
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41
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Jo MS, Rene ER, Kim SH, Park HS. An analysis of synergistic and antagonistic behavior during BTEX removal in batch system using response surface methodology. JOURNAL OF HAZARDOUS MATERIALS 2008; 152:1276-84. [PMID: 17875362 DOI: 10.1016/j.jhazmat.2007.08.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2006] [Revised: 05/05/2007] [Accepted: 08/02/2007] [Indexed: 05/17/2023]
Abstract
The removal of benzene, toluene, ethylbenzene and xylene (BTEX) as quaternary mixtures were studied in batch systems using a well-defined mixed microbial culture. The synergistic and antagonistic effects of total BTEX removal (BTEXT-RE) due to the presence of mixed substrate was evaluated through experiments designed by response surface methodology (RSM). The low and high concentrations of individual BTEX were 15 and 75 mg l(-1), respectively. The results showed that, increasing the concentration of xylene increased the cumulative BTEX removal (BTEXT-RE), however the reverse occurred when benzene concentrations were increased from low to high levels. A mixed response of increasing and decreasing trend in the BTEXT-RE value was observed when either of toluene or ethylbenzene concentration was increased. When the concentrations of individual BTEX compounds were 30 mg l(-1), the BTEXT-RE was about 58%. Complete BTEXT-RE was achieved at optimal BTEX concentrations of 48.1, 45.6, 49.3 and 56.6 mg l(-1). The RSM approach was found efficient in explaining the main, squared and interaction effects among individual BTEX concentrations on the BTEXT-RE in a more statistically meaningful way.
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Affiliation(s)
- Mi-Seon Jo
- Department of Civil and Environmental Engineering, University of Ulsan, San-29 Moogu-2 Dong, Nam-Gu, Ulsan 680-749, South Korea
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42
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Martín MMB, Pérez JAS, Fernández FGA, Sánchez JLG, López JLC, Rodríguez SM. A kinetics study on the biodegradation of synthetic wastewater simulating effluent from an advanced oxidation process using Pseudomonas putida CECT 324. JOURNAL OF HAZARDOUS MATERIALS 2008; 151:780-8. [PMID: 17646049 DOI: 10.1016/j.jhazmat.2007.06.053] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2007] [Revised: 06/11/2007] [Accepted: 06/14/2007] [Indexed: 05/16/2023]
Abstract
Bacterial growth on mixed substrates is employed for wastewater treatment. Biodegradation kinetics of Pseudomonas putida CECT 324 growth on formic acid, vanillin, phenol and oxalic acid mixtures is described. The experiments were carried out in a stirred-tank fermentor in batch mode at different temperatures (25, 30 and 35 degrees C) and pH (5, 6 and 7). The four compounds selected are typical intermediates in pesticide-contaminated water treated by advanced oxidation processes (AOPs). The toxicity of intermediates was investigated for a combined AOP-biological treatment, and the minimum DOC inhibitory concentration of the intermediate mixture was 175 ppm. The resulting biodegradation and growth kinetics were best described by the sum kinetics with interaction parameters (SKIP) model. Phenol and oxalic acid inhibit P. putida growth, and formic acid consumption strongly affects the biodegradation of oxalic acid. At all the temperatures tested and at pH between 5 and 7, P. putida CECT 324 was able to degrade the four substrates after culture times of 30 h at 30 degrees C and pH 7, which were the best conditions, and after 70 h, under the worst, at 35 degrees C.
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43
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Farhadian M, Duchez D, Vachelard C, Larroche C. Monoaromatics removal from polluted water through bioreactors-a review. WATER RESEARCH 2008; 42:1325-1341. [PMID: 18023838 DOI: 10.1016/j.watres.2007.10.021] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2007] [Revised: 09/27/2007] [Accepted: 10/16/2007] [Indexed: 05/25/2023]
Abstract
Water contaminated by oil products is becoming a major problem in water supplies as these organic compounds cause hazards for human health. Different types of aerobic and anaerobic bioreactors have been widely used for water cleanup from organic pollutants such as petroleum hydrocarbons. Many studies report that aerobic biofilm processes are a very efficient method for monoaromatic hydrocarbons removal from contaminated water as they are able to reduce up to 99% of the pollutants from water, but generally these works do not discuss possible pollutant loss through gas stripping. On the other hand, some research is related to the ability of anaerobic bioreactors for monoaromatics treatment and results have shown that anaerobic immobilized reactors are able to remove monoaromatic compounds from water with maximal efficiencies between 95-99%. But here again, no data are found about the amount of volatile organic compounds that can be found in the biogas. Also, the data generated when a solid biomass support (activated carbon, polyurethane, etc.) is present in the medium do not take care about possible solute sorption phenomena. This paper reviews various properties of monoaromatic compounds including benzene, toluene, ethylbenzene and mixture of xylenes. The sources of pollutants, various analytical methods suitable for identification and quantitative measurement of monoaromatics, and knowledge gained on the true removal rates by aerobic and anaerobic bioreactors are reviewed and discussed in this study.
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Affiliation(s)
- Mehrdad Farhadian
- Polytech Clermont-Ferrand, Université Blaise Pascal, Aubière, Cedex, France
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44
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Tsang YF, Chua H, Sin SN, Chan SY. Treatment of odorous volatile fatty acids using a biotrickling filter. BIORESOURCE TECHNOLOGY 2008; 99:589-95. [PMID: 17321131 DOI: 10.1016/j.biortech.2006.12.032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2006] [Revised: 12/21/2006] [Accepted: 12/23/2006] [Indexed: 05/14/2023]
Abstract
In this study, a novel fibrous bioreactor was developed for treating odorous compounds present in contaminated air. The first stage of this work was a preliminary study which aimed at investigating the feasibility of using the fibrous bioreactor for the removal of malodorous volatile fatty acids (VFA) that is a common odorous contaminant generated from anaerobic degradation of organic compounds. The kinetics of microbial growth and VFA degradation in the selected culture, and the performance of the submerged bioreactor at different VFA mass loadings were studied. Above 95% of VFA removal efficiencies were achieved at mass loadings up to 22.4 g/m(3)/h. In the second stage, the odour treatment process was scaled up with system design and operational considerations. A trickling biofilter with synthetic fibrous packing medium was employed. The effects of inlet VFA concentration and empty bed retention time (EBRT) on the process performance were investigated. The bioreactor was effective in removing VFA at mass loadings up to 32 g/m(3)/h, beyond which VFA started to accumulate in the recirculation liquid, indicating the biofilm was unable to degrade all of the VFA introduced. Although VFA accumulated in the liquid phase, the removal efficiency remained above 99%. This suggested that the biochemical reaction rather than gas-liquid mass transfer was the limiting step of the treatment process. In addition, the biotrickling filter was stable for long-term operation with relatively low and steady pressure drop, no clogging and degeneration of the packing material occurred during the four-month study.
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Affiliation(s)
- Y F Tsang
- Department of Civil and Structural Engineering, The Hong Kong Polytechnic University, Hung Hom, Hong Kong.
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45
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Parameswarappa S, Karigar C, Nagenahalli M. Degradation of ethylbenzene by free and immobilized Pseudomonas fluorescens-CS2. Biodegradation 2007; 19:137-44. [PMID: 17534726 DOI: 10.1007/s10532-007-9121-y] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2006] [Accepted: 04/10/2007] [Indexed: 10/23/2022]
Abstract
Pseudomonas fluorescens-CS2 metabolized ethylbenzene as the sole source of carbon and energy. The involvement of catechol as the hydroxylated intermediate during the biodegradation of ethylbenzene was established by TLC, HPLC and enzyme analysis. The specific activity of Catechol 2,3-dioxygenase in the cell free extracts of P. fluorescens-CS2 was determined to be 0.428 micromoles min(-1) mg(-1) protein. An aqueous-organic, Two-Phase Batch Culture System (TPBCS) was developed to overcome inhibition due to higher substrate concentrations. In TPBCS, P. fluorescens-CS2 demonstrated ethylbenzene utilization up to 50 mM without substrate inhibition on inclusion of n-decanol as the second phase. The rate of ethylbenzene metabolism in TPBCS was found enhance by fivefold in comparison with single phase system. Alternatively the alginate, agar and polyacrylamide matrix immobilized P. fluorescens-CS2 cells efficiently degraded ethylebenzene with enhanced efficiency compared to free cell cultures in single and two-phase systems. The cells entrapped in ployacrylamide and alginate were found to be stable and degradation efficient for a period of 42 days where as agar-entrapped P. fluorescens was stable and efficient a period of 36 days. This demonstrates that alginate and polyacrylamide matrices are more promising as compared to agar for cell immobilization.
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Affiliation(s)
- Suneetha Parameswarappa
- Bioremediation Laboratory, Biochemistry Division, Department of Chemistry, Central College Campus, Bangalore University, Bangalore, Karnataka 560001, India
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46
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Lapertot M, Seignez C, Ebrahimi S, Delorme S, Peringer P. Mass production of bacterial communities adapted to the degradation of volatile organic compounds (TEX). Biodegradation 2006; 18:343-50. [PMID: 17091355 DOI: 10.1007/s10532-006-9068-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2005] [Accepted: 07/04/2006] [Indexed: 10/23/2022]
Abstract
This study focuses on the mass cultivation of bacteria adapted to the degradation of a mixture composed of toluene, ethylbenzene, o-, m- and p-xylenes (TEX). For the cultivation process Substrate Pulse Batch (SPB) technique was adapted under well-automated conditions. The key parameters to be monitored were handled by LabVIEW software including, temperature, pH, dissolved oxygen and turbidity. Other parameters, such as biomass, ammonium or residual substrate concentrations needed offline measurements. SPB technique has been successfully tested experimentally on TEX. The overall behavior of the mixed bacterial population was observed and discussed along the cultivation process. Carbon and nitrogen limitations were shown to affect the integrity of the bacterial cells as well as their production of exopolymeric substances (EPS). Average productivity and yield values successfully reached the industrial specifications, which were 0.45 kg(DW)m(-3) d(-1) and 0.59 g(DW)g (C) (-1) , respectively. Accuracy and reproducibility of the obtained results present the controlled SPB process as a feasible technique.
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Affiliation(s)
- Miléna Lapertot
- Laboratory of Environmental Biotechnology, ENAC, Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 6, CH-1015 Lausanne, Switzerland.
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Abstract
Why do bacteria have shape? Is morphology valuable or just a trivial secondary characteristic? Why should bacteria have one shape instead of another? Three broad considerations suggest that bacterial shapes are not accidental but are biologically important: cells adopt uniform morphologies from among a wide variety of possibilities, some cells modify their shape as conditions demand, and morphology can be tracked through evolutionary lineages. All of these imply that shape is a selectable feature that aids survival. The aim of this review is to spell out the physical, environmental, and biological forces that favor different bacterial morphologies and which, therefore, contribute to natural selection. Specifically, cell shape is driven by eight general considerations: nutrient access, cell division and segregation, attachment to surfaces, passive dispersal, active motility, polar differentiation, the need to escape predators, and the advantages of cellular differentiation. Bacteria respond to these forces by performing a type of calculus, integrating over a number of environmental and behavioral factors to produce a size and shape that are optimal for the circumstances in which they live. Just as we are beginning to answer how bacteria create their shapes, it seems reasonable and essential that we expand our efforts to understand why they do so.
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Affiliation(s)
- Kevin D Young
- Department of Microbiology and Immunology, University of North Dakota School of Medicine, Grand Forks, ND 58202-9037, USA.
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48
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Jeong E, Hirai M, Shoda M. Removal of p-Xylene with Pseudomonas sp. NBM21 in biofilter. J Biosci Bioeng 2006; 102:281-7. [PMID: 17116573 DOI: 10.1263/jbb.102.281] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2006] [Accepted: 06/26/2006] [Indexed: 11/17/2022]
Abstract
As a p-xylene (p-Xyl)-degrading microorganism, Pseudomonas sp. NBM21 was isolated from an activated sludge of a wastewater treatment plant. NBM21 degraded p-Xyl, m-xylene, benzene and toluene, but not o-xylene, ethylbenzene (Eb) and styrene. NBM21 was inoculated to a biofilter with Biosol as a packing material and p-Xyl removal was operated for 105 d under sterile and nonsterile conditions. The maximum elimination capacities for p-Xyl at higher than 90% removal efficiency were 160 g/m3/h and 150 g/m3/h under nonsterile and sterile conditions, respectively. A high load of Eb adversely affected to the removal of xylene.
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Affiliation(s)
- Euisoon Jeong
- Chemical Resources Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan
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49
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Lapertot M, Seignez C, Ebrahimi S, Peringer P. Enhancing Production of Adapted Bacteria To Degrade Chlorinated Aromatics. Ind Eng Chem Res 2006. [DOI: 10.1021/ie051408d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Milena Lapertot
- Laboratory of Environmental Biotechnology, ENAC, Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 6, CH-1015 Lausanne, Switzerland
| | - Chantal Seignez
- Laboratory of Environmental Biotechnology, ENAC, Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 6, CH-1015 Lausanne, Switzerland
| | - Sirous Ebrahimi
- Laboratory of Environmental Biotechnology, ENAC, Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 6, CH-1015 Lausanne, Switzerland
| | - Paul Peringer
- Laboratory of Environmental Biotechnology, ENAC, Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 6, CH-1015 Lausanne, Switzerland
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50
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Roychoudhury AN, Merrett GL. Redox pathways in a petroleum contaminated shallow sandy aquifer: Iron and sulfate reductions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2006; 366:262-74. [PMID: 16387349 DOI: 10.1016/j.scitotenv.2005.10.024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2005] [Revised: 10/19/2005] [Accepted: 10/21/2005] [Indexed: 05/06/2023]
Abstract
A comprehensive hydro-geochemical characterization was carried out in a petroleum-contaminated shallow sandy aquifer in South Africa. The results indicate the presence of a BTEX (benzene, toluene, ethylbenzene, and xylene) plume that has moved, although only slightly, along the regional hydraulic gradient from the spill site. Associated with the contaminant plume, spatial distribution pattern of terminal electron acceptors and metabolites indicates simultaneous occurrence of nitrate, manganese, iron and sulfate reductions resulting in overlapping redox zones within the aquifer. From the measured concentration of metabolic by-products, sulfate and iron reductions seem to be the dominant metabolic pathways, though. Incubation experiments conducted with hydrocarbon contaminated aquifer sediments and inherent microbial assemblages provide a sulfate reduction rate of 4272 nmol cm(-3) day(-1) and 96 nmol cm(-3) day(-1) for winter and summer, respectively. As oppose to this, iron reduction dominates in summer with measured respiration rate of 1414 nmol cm(-3) day(-1). In winter iron reduction was measured to be only 24 nmol cm(-3) day(-1). Based on the dissimilatory iron and sulfate reduction rate measurements, we predict that at the aquifer site, intrinsic BTEX oxidation is primarily occurring in winter and is coupled to sulfate reduction. Although widespread in the aquifer, the contribution of iron reduction for the removal of aromatic monocyclic hydrocarbons is relatively minor.
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