The Experts below are selected from a list of 4095 Experts worldwide ranked by ideXlab platform
Bernardo Gonzalez - One of the best experts on this subject based on the ideXlab platform.
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genetic characterization of 2 4 6 trichlorophenol degradation in cupriavidus necator jmp134
Applied and Environmental Microbiology, 2007Co-Authors: M A Sanchez, Bernardo GonzalezAbstract:The degradation pathway of 2,4,6-trichlorophenol (2,4,6-TCP), a Hazardous Pollutant, in the aerobic bacterium Cupriavidus necator JMP134(pJP4) (formerly Ralstonia eutropha JMP134) is encoded by the tcp genes. These genes are located in a genetic context, tcpRXABCYD, which resembles a putative catabolic operon. In this work, these gene sequences were individually disrupted and mutant strains were evaluated for their ability to grow on or degrade 2,4,6-TCP. The tcpX and tcpA mutants completely failed to degrade this compound. Although the tcpC mutant was also unable to grow on 2,4,6-TCP, it still transformed this chlorophenol to 6-chlorohydroquinol. In contrast, the tcpD mutant grew on 2,4,6-TCP, suggesting the presence of additional maleylacetate reductase-encoding genes. Five other open reading frames encoding maleylacetate reductases, in addition to the tcpD gene, were found in the genome of C. necator, and two of them provide this function in the tcpD mutant. The tcpR gene, encoding a putative LysR-type transcriptional regulator, was disrupted, and this mutant strain completely failed to grow on 2,4,6-TCP. Transcriptional fusion studies demonstrated that TcpR activates the expression of the tcp genes, responding specifically to 2,4,6-TCP. The transcriptional start of the tcp operon was mapped, and a putative σ70-type promoter was identified.
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a previously unexposed forest soil microbial community degrades high levels of the Pollutant 2 4 6 trichlorophenol
Applied and Environmental Microbiology, 2004Co-Authors: M A Sanchez, Monica Vasquez, Bernardo GonzalezAbstract:2,4,6-Trichlorophenol (2,4,6-TCP) is a Hazardous Pollutant that is efficiently degraded by some aerobic soil bacterial isolates under laboratory conditions. The degradation of this Pollutant in soils and its effect on the soil microbial community are poorly understood. We report here the ability of a previously unexposed forest soil microbiota to degrade high levels of 2,4,6-TCP and describe the changes in the soil microbial community found by terminal restriction fragment length polymorphism (T-RFLP) analysis. After 30 days of incubation, about 50% degradation of this Pollutant was observed in soils amended with 50 to 5,000 ppm of 2,4,6-TCP. The T-RFLP analysis showed that the soil bacterial community was essentially unchanged after exposure to up to 500 ppm of 2,4,6-TCP. However, a significant decrease in richness was found with 2,000 and 5,000 ppm of 2,4,6-TCP, even though the removal of this Pollutant remained high. The introduction of Ralstonia eutropha JMP134 or R. eutropha MS1, two efficient 2,4,6-TCP degraders, to this soil did not improve degradation of this Pollutant, supporting the significant bioremediation potential of this previously unexposed, endogenous forest soil microbial community.
M A Sanchez - One of the best experts on this subject based on the ideXlab platform.
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genetic characterization of 2 4 6 trichlorophenol degradation in cupriavidus necator jmp134
Applied and Environmental Microbiology, 2007Co-Authors: M A Sanchez, Bernardo GonzalezAbstract:The degradation pathway of 2,4,6-trichlorophenol (2,4,6-TCP), a Hazardous Pollutant, in the aerobic bacterium Cupriavidus necator JMP134(pJP4) (formerly Ralstonia eutropha JMP134) is encoded by the tcp genes. These genes are located in a genetic context, tcpRXABCYD, which resembles a putative catabolic operon. In this work, these gene sequences were individually disrupted and mutant strains were evaluated for their ability to grow on or degrade 2,4,6-TCP. The tcpX and tcpA mutants completely failed to degrade this compound. Although the tcpC mutant was also unable to grow on 2,4,6-TCP, it still transformed this chlorophenol to 6-chlorohydroquinol. In contrast, the tcpD mutant grew on 2,4,6-TCP, suggesting the presence of additional maleylacetate reductase-encoding genes. Five other open reading frames encoding maleylacetate reductases, in addition to the tcpD gene, were found in the genome of C. necator, and two of them provide this function in the tcpD mutant. The tcpR gene, encoding a putative LysR-type transcriptional regulator, was disrupted, and this mutant strain completely failed to grow on 2,4,6-TCP. Transcriptional fusion studies demonstrated that TcpR activates the expression of the tcp genes, responding specifically to 2,4,6-TCP. The transcriptional start of the tcp operon was mapped, and a putative σ70-type promoter was identified.
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a previously unexposed forest soil microbial community degrades high levels of the Pollutant 2 4 6 trichlorophenol
Applied and Environmental Microbiology, 2004Co-Authors: M A Sanchez, Monica Vasquez, Bernardo GonzalezAbstract:2,4,6-Trichlorophenol (2,4,6-TCP) is a Hazardous Pollutant that is efficiently degraded by some aerobic soil bacterial isolates under laboratory conditions. The degradation of this Pollutant in soils and its effect on the soil microbial community are poorly understood. We report here the ability of a previously unexposed forest soil microbiota to degrade high levels of 2,4,6-TCP and describe the changes in the soil microbial community found by terminal restriction fragment length polymorphism (T-RFLP) analysis. After 30 days of incubation, about 50% degradation of this Pollutant was observed in soils amended with 50 to 5,000 ppm of 2,4,6-TCP. The T-RFLP analysis showed that the soil bacterial community was essentially unchanged after exposure to up to 500 ppm of 2,4,6-TCP. However, a significant decrease in richness was found with 2,000 and 5,000 ppm of 2,4,6-TCP, even though the removal of this Pollutant remained high. The introduction of Ralstonia eutropha JMP134 or R. eutropha MS1, two efficient 2,4,6-TCP degraders, to this soil did not improve degradation of this Pollutant, supporting the significant bioremediation potential of this previously unexposed, endogenous forest soil microbial community.
Manuel A Rodrigo - One of the best experts on this subject based on the ideXlab platform.
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A new electrochemically-based process for the removal of perchloroethylene from gaseous effluents
Chemical Engineering Journal, 2019Co-Authors: M. Muñoz-morales, Cristina Saez, Pablo Cañizares, Manuel A RodrigoAbstract:Abstract Removal of perchloroethylene using combined granular active carbon (GAC) adsorption and electrolysis is evaluated in this research. There is an interest in the regeneration of GAC using methanol solutions, because this process can obtain the almost complete desorption of the Pollutant retained during the treatment of gaseous flows. In this work, the electrolysis of perchloroethylene (used not only as a Hazardous Pollutant but also as a model of organic Pollutant) in methanol media containing sodium chloride and sodium hydroxide is evaluated and results are compared to those obtained during the electrolysis of this Pollutant in aqueous media. Results demonstrate the feasibility of this treatment technology, which does not only remove the raw molecule but it is also capable to remove all the intermediates detected by GC-ECD, allowing the possibility of the reuse of the methanol solution for further regeneration steps.
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remediation of soils polluted with lindane using surfactant aided soil washing and electrochemical oxidation
Journal of Hazardous Materials, 2017Co-Authors: M Munozmorales, M Braojos, Cristina Saez, Pablo Cañizares, Manuel A RodrigoAbstract:Abstract In this work the complete treatment of soil spiked with lindane is studied using surfactant-aided soil-washing (SASW) to exhaust lindane from soil and electrolysis with diamond anodes to mineralize lindane from the soil washing fluid (SWF) waste. Results demonstrated that this technological approach is efficient and allow to remove this Hazardous Pollutant from soil. They also pointed out the significance of the ratio surfactant/soil in the efficiency of the SASW process and in the performance of the later electrolysis used to mineralize the Pollutant. Larger values of this parameter lead to effluents that undergo a very efficient treatment which allows the depletion of lindane for applied charges lower than 15 Ah L −1 and the recovery of more than 70% of the surfactant for the regeneration of the SWF.
Arjun Maity - One of the best experts on this subject based on the ideXlab platform.
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high performance hg ii removal using thiol functionalized polypyrrole ppy maa composite and effective catalytic activity of hg ii adsorbed waste material
ACS Sustainable Chemistry & Engineering, 2017Co-Authors: Raghunath Das, Somnath Giri, Anthony M Muliwa, Arjun MaityAbstract:Problems related with highly toxic mercury emissions from industrial effluents are one of the great concerns in the world of environmental science and technology. The primary aim of this present work is the remediation of Hazardous Pollutant Hg (II) from aqueous medium via a thiol-functionalized (mercaptoacetic acid) conducting polypyrrole (PPy/MAA) composite. The synthesized composite exhibited high Hg(II) adsorption capacity as the incorporated mercapto functionality plays a vital role for the strong binding affinity toward Hg(II) ions. To understand the adsorption properties of the developed polymer composite, a series of batch adsorption experiments were performed by altering the adsorption parameters. A maximum adsorption capacity (qmax) of 1736.8 mg/g at 25 °C was obtained using the Langmuir isotherm. The adsorption data showed better fitting to the pseudo-second-order rate equation for Hg(II) adsorption. A plausible adsorption mechanism is suggested on the basis of XPS results of major elements pre...
Monica Vasquez - One of the best experts on this subject based on the ideXlab platform.
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a previously unexposed forest soil microbial community degrades high levels of the Pollutant 2 4 6 trichlorophenol
Applied and Environmental Microbiology, 2004Co-Authors: M A Sanchez, Monica Vasquez, Bernardo GonzalezAbstract:2,4,6-Trichlorophenol (2,4,6-TCP) is a Hazardous Pollutant that is efficiently degraded by some aerobic soil bacterial isolates under laboratory conditions. The degradation of this Pollutant in soils and its effect on the soil microbial community are poorly understood. We report here the ability of a previously unexposed forest soil microbiota to degrade high levels of 2,4,6-TCP and describe the changes in the soil microbial community found by terminal restriction fragment length polymorphism (T-RFLP) analysis. After 30 days of incubation, about 50% degradation of this Pollutant was observed in soils amended with 50 to 5,000 ppm of 2,4,6-TCP. The T-RFLP analysis showed that the soil bacterial community was essentially unchanged after exposure to up to 500 ppm of 2,4,6-TCP. However, a significant decrease in richness was found with 2,000 and 5,000 ppm of 2,4,6-TCP, even though the removal of this Pollutant remained high. The introduction of Ralstonia eutropha JMP134 or R. eutropha MS1, two efficient 2,4,6-TCP degraders, to this soil did not improve degradation of this Pollutant, supporting the significant bioremediation potential of this previously unexposed, endogenous forest soil microbial community.
