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Jones SZ, Bentz DP, Davis JM, Hussey DS, Jacobson DL, Molloy JL, Sieber JR. Measurement and Modeling of the Ability of Crack Fillers to Prevent Chloride Ingress into Mortar. CEMENT & CONCRETE COMPOSITES 2017; 81:109-121. [PMID: 28785136 PMCID: PMC5544028 DOI: 10.1016/j.cemconcomp.2017.05.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A common repair procedures applied to damaged concrete is to fill cracks with an organic polymer. This operation is performed to increase the service life of the concrete by removing a preferential pathway for the ingress of water, chlorides, and other deleterious species. To effectively fulfill its mission of preventing chloride ingress, the polymer must not only fully fill the macro-crack, but must also intrude the damage zone surrounding the crack perimeter. Here, the performance of two commonly employed crack fillers, one epoxy, and one methacrylate, are investigated using a combined experimental and computer modeling approach. Neutron tomography and microbeam X-ray fluorescence spectrometry (μXRF) measurements are employed on pre-cracked and chloride-exposed specimens to quantify the crack filling and chloride ingress limiting abilities, respectively, of the two polymers. A two-dimensional model of chloride transport is derived from a mass balance and solved by the finite element method. Crack images provided by μXRF are used to generate the input microstructure for the simulations. When chloride binding and a time-dependent mortar diffusivity are both included in the computer model, good agreement with the experimental results is obtained. Both crack fillers significantly reduce chloride ingress during the 21 d period of the present experiments; however, the epoxy itself contains approximately 4 % by mass chlorine. Leaching studies were performed assess the epoxy as a source of deleterious ions for initiating corrosion of the steel reinforcement in concrete structures.
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Affiliation(s)
- Scott Z Jones
- National Institute of Standards and Technology, Materials and Structural Systems Division, 100 Bureau Drive, Gaithersburg, MD 20899, ,
| | - Dale P Bentz
- National Institute of Standards and Technology, Materials and Structural Systems Division, 100 Bureau Drive, Gaithersburg, MD 20899, ,
| | | | - Daniel S Hussey
- National Institute of Standards and Technology, Radiation Physics Division, ,
| | - David L Jacobson
- National Institute of Standards and Technology, Radiation Physics Division, ,
| | - John L Molloy
- National Institute of Standards and Technology, Chemical Sciences Division, ,
| | - John R Sieber
- National Institute of Standards and Technology, Chemical Sciences Division, ,
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Li H, Pan G. Enhanced and continued degradation of microcystins using microorganisms obtained through natural media. J Microbiol Methods 2013; 96:73-80. [PMID: 24246232 DOI: 10.1016/j.mimet.2013.11.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Revised: 11/05/2013] [Accepted: 11/05/2013] [Indexed: 10/26/2022]
Abstract
Microorganisms isolated through artificial media are often unsustainable in biodegrading microcystins (MCs) in natural water. Here we studied alternative approaches to isolate MCs-degrading bacteria using natural media. In comparison to two species (MS-1 and MS-2) isolated from artificial media and the failure of bacterial colonies formation using water extracts of sediment (10%, w/v), five colony species (WC-1 to WC-5) appeared using concentrated water extracts of sediment that is 10-fold enhancement of nutrient level. In the simulated biodegradation test in Lake Taihu water with continuous supply of MCs, a lag phase of 6days was required for MS-1 and M-2 to degrade 13% and 15% of the added MC-RR and MC-LR, respectively, whereas the lag phase was only 3days with approximately 44% and 31% removal of the added MC-RR and MC-LR by WC-1 to WC-5. During the continuous supply experiment, degradation of MCs by MS-1 and MS-2 stopped after 3days, while degradation of MCs by WC-1 to WC-5 lasted continuously throughout the 18day test period with 2 to 6-fold enhancement of removal rate. 16S rRNA gene sequences and phylogenetic analysis indicated the potential to amplify species of MCs-degrading bacteria when natural media were used. The results suggested that the increased adaptability of bacteria obtained through concentrated natural media was responsible for the enhanced and continued biodegradation under simulated natural water conditions.
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Affiliation(s)
- Hong Li
- Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, People's Republic of China
| | - Gang Pan
- Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, People's Republic of China.
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Meffe R, Kohfahl C, Holzbecher E, Massmann G, Richter D, Dünnbier U, Pekdeger A. Modelling the removal of p-TSA (para-toluenesulfonamide) during rapid sand filtration used for drinking water treatment. WATER RESEARCH 2010; 44:205-213. [PMID: 19766287 DOI: 10.1016/j.watres.2009.08.046] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2009] [Revised: 08/27/2009] [Accepted: 08/31/2009] [Indexed: 05/28/2023]
Abstract
A finite element model was set-up to determine degradation rate constants for p-TSA during rapid sand filtration (RSF). Data used for the model originated from a column experiment carried out in the filter hall of a drinking water treatment plant in Berlin (Germany). Aerated abstracted groundwater was passed through a 1.6m long column-shaped experimental sand filter applying infiltration rates from 2 to 6mh(-1). Model results were fitted to measured profiles and breakthrough curves of p-TSA for different infiltration rates using both first-order reaction kinetics and Michaelis-Menten kinetics. Both approaches showed that degradation rates varied both in space and time. Higher degradation rates were observed in the upper part of the column, probably related to higher microbial activity in this zone. Measured and simulated breakthrough curves revealed an adaption phase with lower degradation rates after infiltration rates were changed, followed by an adapted phase with more elevated degradation rates. Irrespective of the mathematical approach and the infiltration rate, degradation rates were very high, probably owing to the fact that filter sands have been in operation for decades, receiving high p-TSA concentrations with the raw water.
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Affiliation(s)
- Raffaella Meffe
- Institute of Geological Sciences, Freie Universität Berlin, Malteserstr. 74-100, 12249 Berlin, Germany.
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Lissner A, Hüttl R, Frank N, Mertens FO. Calorimetric investigations into the starvation response of Pseudomonas putida growing on phenol and glucose. J Appl Microbiol 2009; 107:1984-90. [PMID: 19583802 DOI: 10.1111/j.1365-2672.2009.04381.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
AIMS To investigate the stress response during nutrient deprivation, particularly with regard to the application of phenol as growth substrate of Pseudomonas putida with calorimetric measurements as a new method. METHODS AND RESULTS The online and noninvasive measurement of the thermal power P(0) permits the detection of microbial activity during the starvation period. While the results of the investigations with phenol reveal a significant loss of activity as a function of the temporal nutrient dosage, only a small loss of activity was detected by using glucose. Microbiological methods (colony forming units (CFU) and activity of catechol-2,3-dioxygenase) showed a loss of the enzyme activity at a constant CFU. The introduction of a simple decay parameter k(D) in the kinetic description of the growth process on phenol was sufficient for the successful kinetic modelling. CONCLUSIONS The combination of calorimetric measurements and the determination of the enzymatic activity proved the loss of activity of Ps. putida during the deprivation of the substrate phenol. SIGNIFICANCE AND IMPACT OF THE STUDY The initial heat power (P(0)) proves to be a suitable parameter for the characterization of the physiological state of the culture and can be used for the regulation of nutrient supply in biotechnological process development.
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Affiliation(s)
- Andreas Lissner
- Technische Universität Bergakademie Freiberg, Institut für Physikalische Chemie, Freiberg, Germany
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Syron E, Kelly H, Casey E. Studies on the effect of concentration of a self-inhibitory substrate on biofilm reaction rate under co-diffusion and counter-diffusion configurations. J Memb Sci 2009. [DOI: 10.1016/j.memsci.2009.02.038] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Pandey J, Chauhan A, Jain RK. Integrative approaches for assessing the ecological sustainability ofin situbioremediation. FEMS Microbiol Rev 2009; 33:324-75. [PMID: 19178567 DOI: 10.1111/j.1574-6976.2008.00133.x] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
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Benzene degradation by Ralstonia pickettii PKO1 in the presence of the alternative substrate succinate. Biodegradation 2008; 20:419-31. [DOI: 10.1007/s10532-008-9233-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2008] [Accepted: 10/27/2008] [Indexed: 11/25/2022]
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Kim HS, Jaffé PR. Spatial distribution and physiological state of bacteria in a sand column experiment during the biodegradation of toluene. WATER RESEARCH 2007; 41:2089-100. [PMID: 17397899 DOI: 10.1016/j.watres.2007.02.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2006] [Revised: 02/08/2007] [Accepted: 02/15/2007] [Indexed: 05/14/2023]
Abstract
Toxic organic contaminants frequently serve as growth substrates for bacteria. However, long-term exposure to the organic contaminants can result in significant stress or "injury" to bacterial cells such that bacteria may lose, either temporarily or permanently, their capacity to degrade a specific toxic organic contaminant. In order to understand the relationship between biodegradability and physiological conditions of bacteria after a prolonged exposure to a contaminant, biomass samples collected from a sand column experiment, with toluene as the carbon source, were analyzed for bacterial physiology and spatial population distribution in the porous media. The column was seeded with three bacterial isolates that perform aerobic (Pseudomonas putida F1), denitrifying (Thauera aromatica T1), and facultative (Ralstonia pickettii PKO1) degradation of toluene were analyzed. Total, viable but not culturable with toluene, and toluene-culturable cells were enumerated using 4'6-diamidino-2-phenylindole (DAPI) staining and plate counting methods. Comparison of three types of cell counts showed that toluene-culturable cells were less than 40% of the total cell numbers. However, viable colonies transferred to a toluene media after cultivation on rich media regained their ability to degrade toluene. This implies that the temporary loss of their toluene degradation capacity is either due to an intracellular accumulation of degradation by-products, which have to be consumed in order for the cells to degrade toluene, or it is possible that cells have shifted to degrade other substrates such as toluene degradation intermediates or organic materials resulting from cell turnover. Comparison of cell counts with toluene concentration showed no exponential increase in total and viable cell numbers, as reported for flat bed biofilm reactor experiments. The overall fraction of toluene-culturable cells was highest at the highest toluene concentration near the column inlet, which indicates that the observed temporary loss of toluene culturability was not solely caused by a direct toxic effect from the long-term exposure to toluene.
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Affiliation(s)
- Hyun-Su Kim
- Department of Civil and Environmental Engineering, Princeton University, Princeton, NJ 08544, USA
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Johnson DR, Park J, Kukor JJ, Abriola LM. Effect of carbon starvation on toluene degradation activity by toluene monooxygenase-expressing bacteria. Biodegradation 2006; 17:437-45. [PMID: 16477358 DOI: 10.1007/s10532-005-9014-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/08/2005] [Indexed: 11/29/2022]
Abstract
Subsurface bacteria commonly exist in a starvation state with only periodic exposure to utilizable sources of carbon and energy. In this study, the effect of carbon starvation on aerobic toluene degradation was quantitatively evaluated with a selection of bacteria representing all the known toluene oxygenase enzyme pathways. For all the investigated strains, the rate of toluene biodegradation decreased exponentially with starvation time. First-order deactivation rate constants for TMO-expressing bacteria were approximately an order of magnitude greater than those for other oxygenase-expressing bacteria. When growth conditions (the type of growth substrate and the type and concentration of toluene oxygenase inducer) were varied in the cultures prior to the deactivation experiments, the rate of deactivation was not significantly affected, suggesting that the rate of deactivation is independent of previous substrate/inducer conditions. Because TMO-expressing bacteria are known to efficiently detoxify TCE in subsurface environments, these findings have significant implications for in situ TCE bioremediation, specifically for environments experiencing variable growth-substrate exposure conditions.
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Affiliation(s)
- David R Johnson
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, MI 48109-2125, USA
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Park J, Malinverni J, Adriaens P, Kukor JJ. Quantitative structure-activity relationship (QSAR) analysis of aromatic effector specificity in NtrC-like transcriptional activators from aromatic oxidizing bacteria. FEMS Microbiol Lett 2003; 224:45-52. [PMID: 12855166 DOI: 10.1016/s0378-1097(03)00400-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
A quantitative structure-activity relationship (QSAR) approach was taken to provide mechanistic insights into the interaction between the chemical structure of inducing compounds and the transcriptional activation of aromatic monooxygenase operons among the XylR/DmpR subclass of bacterial NtrC-like transcriptional regulators. Compared to XylR and DmpR, a broader spectrum of effector compounds was observed for the TbuT system from Ralstonia pickettii PKO1. The results of QSAR analysis for TbuT suggested that a steric effect, rather than hydrophobic or electronic effects, may be the predominant factor in determining aromatic effector specificity, and the active site of the regulator may positively interact not only with the methyl moiety but also with the most electron-rich aryl side of an aromatic effector.
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Affiliation(s)
- Joonhong Park
- Center for Microbial Ecology, Michigan State University, A528 PSS Building, East Lansing, MI 48824, USA
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Abstract
Microbial reactions are a key determinant in natural attenuation. However, providing unequivocal evidence of the extent of their involvement is challenging. Several approaches are being developed to meet this challenge, including the use of contaminant-specific transformation products, carbon- or hydrogen-based stable isotopic analysis and reactive transport modeling. These approaches emphasize the ongoing need to integrate strategically between temporally and spatially variant geochemical conditions, the ecological characteristics of the resident microbial communities and their resultant pollutant-transformation capabilities.
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Affiliation(s)
- Barth F Smets
- Department of Civil and Environmental Engineering and Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269-3037, USA.
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Park J, Kukor JJ, Abriola LM. Characterization of the adaptive response to trichloroethylene-mediated stresses in Ralstonia pickettii PKO1. Appl Environ Microbiol 2002; 68:5231-40. [PMID: 12406709 PMCID: PMC129943 DOI: 10.1128/aem.68.11.5231-5240.2002] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In Ralstonia pickettii PKO1, a denitrifying toluene oxidizer that carries a toluene-3-monooxygenase (T3MO) pathway, the biodegradation of toluene and trichloroethylene (TCE) by the organism is induced by TCE at high concentrations. In this study, the effect of TCE preexposure was studied in the context of bacterial protective response to TCE-mediated toxicity in this organism. The results of TCE degradation experiments showed that cells induced by TCE at 110 mg/liter were more tolerant to TCE-mediated stress than were those induced by TCE at lower concentrations, indicating an ability of PKO1 to adapt to TCE-mediated stress. To characterize the bacterial protective response to TCE-mediated stress, the effect of TCE itself (solvent stress) was isolated from TCE degradation-dependent stress (toxic intermediate stress) in the subsequent chlorinated ethylene toxicity assays with both nondegradable tetrachloroethylene and degradable TCE. The results of the toxicity assays showed that TCE preexposure led to an increase in tolerance to TCE degradation-dependent stress rather than to solvent stress. The possibility that such tolerance was selected by TCE degradation-dependent stress during TCE preexposure was ruled out because a similar extent of tolerance was observed in cells that were induced by toluene, whose metabolism does not produce any toxic products. These findings suggest that the adaptation of TCE-induced cells to TCE degradation-dependent stress was caused by the combined effects of solvent stress response and T3MO pathway expression.
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Affiliation(s)
- Joonhong Park
- Center for Microbial Ecology, Michigan State University, East Lansing, Michigan 48824-1325, USA
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