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Li J, Kumar A, Lewis JC. Non-native Intramolecular Radical Cyclization Catalyzed by a B 12 -Dependent Enzyme. Angew Chem Int Ed Engl 2023; 62:e202312893. [PMID: 37874184 PMCID: PMC11328698 DOI: 10.1002/anie.202312893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 10/12/2023] [Accepted: 10/23/2023] [Indexed: 10/25/2023]
Abstract
Despite the unique reactivity of vitamin B12 and its derivatives, B12 -dependent enzymes remain underutilized in biocatalysis. In this study, we repurposed the B12 -dependent transcription factor CarH to enable non-native radical cyclization reactions. An engineered variant of this enzyme, CarH*, catalyzes the formation γ- and δ-lactams through either redox-neutral or reductive ring closure with marked enhancement of reactivity and selectivity relative to the free B12 cofactor. CarH* also catalyzes an unusual spirocyclization by dearomatization of pendant arenes to produce bicyclic 1,3-diene products instead of 1,4-dienes provided by existing methods. These results and associated mechanistic studies highlight the importance of protein scaffolds for controlling the reactivity of B12 and expanding the synthetic utility of B12 -dependent enzymes.
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Affiliation(s)
- Jianbin Li
- Department of Chemistry, Indiana University, Bloomington, IN 47405, USA
| | - Amardeep Kumar
- Department of Chemistry, Indiana University, Bloomington, IN 47405, USA
| | - Jared C Lewis
- Department of Chemistry, Indiana University, Bloomington, IN 47405, USA
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2
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Sun J, Jennepalli S, Lee M, Jones A, O'Carroll DM, Manefield MJ, Bhadbhade M, Åkermark B, Das B, Kumar N. Efficient Reductive Defluorination of Branched PFOS by Metal-Porphyrin Complexes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:7830-7839. [PMID: 35656584 DOI: 10.1021/acs.est.1c08254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Vitamin B12 (VB12) has been reported to degrade PFOS in the presence of TiIII citrate at 70 °C. Porphyrin-based catalysts have emerged as VB12 analogues and have been successfully used in various fields of research due to their interesting structural and electronic properties. However, there is inadequate information on the use of these porphyrin-based metal complexes in the defluorination of PFOS. We have therefore explored a series of porphyrin-based metal complexes for the degradation of PFOS. CoII-5,10,15,20-tetraphenyl-21H,23H-porphyrin (CoII-TPP), CoII-5,10,15,20-tetrakis(4-methoxyphenyl)-21H,23H-porphyrin (CoII-M-TPP), and CoIII-M-TPP exhibited efficient reductive defluorination of the branched PFOS. Within 5-8 h, these compounds achieved the same level of PFOS defluorination as VB12 achieved in 7-10 days. For branched isomers, the specific removal rate of the CoII-TPP-TiIII citrate system is 64-105 times higher than that for VB12-TiIII citrate. Moreover, the CoII-TPP-TiIII citrate system displayed efficient (51%) defluorination for the branched PFOS (br-PFOS) in 1 day even at room temperature (25 °C). The effects of the iron and cobalt metal centers, reaction pH, and several reductants (NaBH4, nanosized zerovalent zinc (nZn0), and TiIII citrate) were systematically investigated. Based on the analysis of the products and previously published reports, a new possible defluorination pathway of branched PFOS is also proposed.
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Affiliation(s)
- Jun Sun
- School of Chemistry, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Sreenu Jennepalli
- Department of Cell, Developmental and Cancer Biology, Center for Experimental Therapeutics, Knight Cancer Institute, Oregon Health and Science University, Portland, Oregon 97201, United States
| | - Matthew Lee
- School of Civil and Environmental Engineering, Water Research Centre, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Adele Jones
- School of Civil and Environmental Engineering, Water Research Centre, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Denis M O'Carroll
- School of Civil and Environmental Engineering, Water Research Centre, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Michael J Manefield
- School of Civil and Environmental Engineering, Water Research Centre, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Mohan Bhadbhade
- Mark Wainwright Analytical Centre, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Björn Åkermark
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, Svante Arrhenius väg 16C, SE-10691 Stockholm, Sweden
| | - Biswanath Das
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, Svante Arrhenius väg 16C, SE-10691 Stockholm, Sweden
| | - Naresh Kumar
- School of Chemistry, The University of New South Wales, Sydney, NSW 2052, Australia
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Metagenomic- and Cultivation-Based Exploration of Anaerobic Chloroform Biotransformation in Hypersaline Sediments as Natural Source of Chloromethanes. Microorganisms 2020; 8:microorganisms8050665. [PMID: 32370295 PMCID: PMC7284496 DOI: 10.3390/microorganisms8050665] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 04/22/2020] [Accepted: 04/29/2020] [Indexed: 01/23/2023] Open
Abstract
Chloroform (CF) is an environmental contaminant that can be naturally formed in various environments ranging from forest soils to salt lakes. Here we investigated CF removal potential in sediments obtained from hypersaline lakes in Western Australia. Reductive dechlorination of CF to dichloromethane (DCM) was observed in enrichment cultures derived from sediments of Lake Strawbridge, which has been reported as a natural source of CF. No CF removal was observed in abiotic control cultures without artificial electron donors, indicating biotic CF dechlorination in the enrichment cultures. Increasing vitamin B12 concentration from 0.04 to 4 µM in enrichment cultures enhanced CF removal and reduced DCM formation. In cultures amended with 4 µM vitamin B12 and 13C labelled CF, formation of 13CO2 was detected. Known organohalide-respiring bacteria and reductive dehalogenase genes were neither detected using quantitative PCR nor metagenomic analysis of the enrichment cultures. Rather, members of the order Clostridiales, known to co-metabolically transform CF to DCM and CO2, were detected. Accordingly, metagenome-assembled genomes of Clostridiales encoded enzymatic repertoires for the Wood-Ljungdahl pathway and cobalamin biosynthesis, which are known to be involved in fortuitous and nonspecific CF transformation. This study indicates that hypersaline lake microbiomes may act as a filter to reduce CF emission to the atmosphere.
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Lee YC, Chen YP, Chen MJ, Kuo J, Lo SL. Reductive defluorination of perfluorooctanoic acid by titanium(III) citrate with vitamin B 12 and copper nanoparticles. JOURNAL OF HAZARDOUS MATERIALS 2017; 340:336-343. [PMID: 28728112 DOI: 10.1016/j.jhazmat.2017.06.020] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2017] [Revised: 05/22/2017] [Accepted: 06/10/2017] [Indexed: 06/07/2023]
Abstract
Perfluorooctanoic acid (PFOA) is widespread in the environment, which causes serious health and safety concerns. A mechanistic study on reductive defluorination of PFOA by titanium(III) citrate in the presence of catalysts was conducted. Vitamin B12 was used to catalyze reduction reactions by shuttling electrons from a reducing agent (electron donor) to PFOA to produce a Co-carbon bond intermediates. In the presence of copper nanoparticles, a precursor complex, B12-C7F14COOH, adsorbed on the metal surface, followed by a hydrogenolytic reaction to form less-fluorinated products. The synergistic effect between vitamin B12 and copper nanoparticles enhances the reductive activities by electron-transfer reactions and hydrogenolysis. The efficient reduction of PFOA to less-noxious compounds was demonstrated with a copper dose of 2gL-1, titanium(III) citrate (45mM), and vitamin B12 (0.2mM) with an initial pH of 9.0 and 70°C. In this anoxic aqueous solution, the biomimetic reductive system effectively removed 65% of PFOA. The mass balance on fluoride matched the observed degradation of PFOA, while no short-chain intermediates were detected.
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Affiliation(s)
- Yu-Chi Lee
- Research Center for Environmental Pollution Prevention and Control Technology, Graduate Institute of Environmental Engineering, National Taiwan University, 71, Chou-Shan Rd., Taipei 106, Taiwan, ROC
| | - Yi-Pei Chen
- Research Center for Environmental Pollution Prevention and Control Technology, Graduate Institute of Environmental Engineering, National Taiwan University, 71, Chou-Shan Rd., Taipei 106, Taiwan, ROC
| | - Meng-Jia Chen
- Research Center for Environmental Pollution Prevention and Control Technology, Graduate Institute of Environmental Engineering, National Taiwan University, 71, Chou-Shan Rd., Taipei 106, Taiwan, ROC
| | - Jeff Kuo
- Department of Civil and Environmental Engineering, California State University, 800 N. State College Blvd., Fullerton, USA
| | - Shang-Lien Lo
- Research Center for Environmental Pollution Prevention and Control Technology, Graduate Institute of Environmental Engineering, National Taiwan University, 71, Chou-Shan Rd., Taipei 106, Taiwan, ROC.
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Vickstrom KE, Azizian MF, Semprini L. Transformation of carbon tetrachloride and chloroform by trichloroethene respiring anaerobic mixed cultures and supernatant. CHEMOSPHERE 2017; 182:65-75. [PMID: 28494362 DOI: 10.1016/j.chemosphere.2017.04.139] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Revised: 04/26/2017] [Accepted: 04/27/2017] [Indexed: 06/07/2023]
Abstract
Carbon tetrachloride (CT) and chloroform (CF) were transformed in batch reactor experiments conducted with anaerobic dechlorinating cultures and supernatant (ADC + S) harvested from continuous flow reactors. The Evanite (EV) and Victoria/Stanford (VS) cultures, capable of respiring trichloroethene (TCE), 1,2-cis-dichloroethene (cDCE), and vinyl chloride (VC) to ethene (ETH), were grown in continuous flow reactors receiving an influent feed of saturated TCE (10 mM; 60 mEq) and formate (45 mM; 90 mEq) but no CT or CF. Cells and supernatant were harvested from the chemostats and inoculated into batch reactors at the onset of each experiment. CT transformation was complete following first order kinetics with CF, DCM and CS2 as the measurable transformation products, representing 20-40% of the original mass of CT, with CO2 likely the unknown transformation product. CF was transformed to DCM and likely CO2 at an order of magnitude rate lower than CT, while DCM was not further transformed. An analytical first order model including multiple key reactions effectively simulated CT transformation, product formation and transformation, and provided reasonable estimates of transformation rate coefficients. Biotic and abiotic treatments indicated that CT was mainly transformed via abiotic processes. However, the presence of live cells was associated with the transformation of CF to DCM. In biotic tests both TCE and CT were simultaneously transformed, with TCE transformed to ETH and approximately 15-53% less CF formed via CT transformation. A 14-day exposure to CF (CFmax = 1.4 μM) reduced all rates of chlorinated ethene respiration by a factor of 10 or greater.
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Affiliation(s)
- Kyle E Vickstrom
- School of Chemical, Biological, and Environmental Engineering, 102 Gleeson Hall, Oregon State University, Corvallis, OR 97331, United States
| | - Mohammad F Azizian
- School of Chemical, Biological, and Environmental Engineering, 102 Gleeson Hall, Oregon State University, Corvallis, OR 97331, United States
| | - Lewis Semprini
- School of Chemical, Biological, and Environmental Engineering, 102 Gleeson Hall, Oregon State University, Corvallis, OR 97331, United States.
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Zhu W, Huang T, Li M, Zheng L, Bao S, Kobayashi N, Liang X. A New Strategy towards Efficient and Recyclable Carbon-Chloride Bond Cleavage of Environmentally Harmful Organochlorides through Electrochemical Catalysis in Non-aqueous Media. ChemistrySelect 2017. [DOI: 10.1002/slct.201601603] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Weihua Zhu
- School of Chemistry and Chemical Engineering; Jiangsu University; Zhenjiang 212013 P. R. China
| | - Tingting Huang
- School of Chemistry and Chemical Engineering; Jiangsu University; Zhenjiang 212013 P. R. China
| | - Minzhi Li
- School of Chemistry and Chemical Engineering; Jiangsu University; Zhenjiang 212013 P. R. China
| | - Limin Zheng
- School of Chemistry and Chemical Engineering; Nanjing University; Nanjing 210093 P. R. China
| | - Songsong Bao
- School of Chemistry and Chemical Engineering; Nanjing University; Nanjing 210093 P. R. China
| | - Nagao Kobayashi
- Faculty of Textile Science and Technology; Shinshu University; Ueda 386-8567 Japan
| | - Xu Liang
- School of Chemistry and Chemical Engineering; Jiangsu University; Zhenjiang 212013 P. R. China
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Zhu W, Huang T, Qin M, Li M, Mack J, Liang X. Tuning the synthetic cobalt(III)corroles electroreductive catalyzed lindane dehalogenation reactivity through meso-substituents. J Electroanal Chem (Lausanne) 2016. [DOI: 10.1016/j.jelechem.2016.05.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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8
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Shimakoshi H, Luo Z, Inaba T, Hisaeda Y. Electrolysis of trichloromethylated organic compounds under aerobic conditions catalyzed by the B12 model complex for ester and amide formation. Dalton Trans 2016; 45:10173-80. [DOI: 10.1039/c6dt00556j] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Electrolysis of trichlorinated organic compounds catalyzed by B12 model complex provided ester or amide under aerobic conditions.
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Affiliation(s)
- Hisashi Shimakoshi
- Department of Chemistry and Biochemistry
- Graduate School of Engineering
- Kyushu University
- Motooka
- Japan
| | - Zhongli Luo
- Department of Chemistry and Biochemistry
- Graduate School of Engineering
- Kyushu University
- Motooka
- Japan
| | - Takuya Inaba
- Department of Chemistry and Biochemistry
- Graduate School of Engineering
- Kyushu University
- Motooka
- Japan
| | - Yoshio Hisaeda
- Department of Chemistry and Biochemistry
- Graduate School of Engineering
- Kyushu University
- Motooka
- Japan
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9
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Kim S, Park T, Lee W. Enhanced reductive dechlorination of tetrachloroethene by nano-sized mackinawite with cyanocobalamin in a highly alkaline condition. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2015; 151:378-385. [PMID: 25590608 DOI: 10.1016/j.jenvman.2015.01.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2014] [Revised: 01/02/2015] [Accepted: 01/04/2015] [Indexed: 06/04/2023]
Abstract
In this study, we characterize the reductive dechlorination of tetrachloroethene (PCE) by nano-sized mackinawite (nFeS) with cobalamin (Cbl(III)) at a high pH and investigate the effects of environmental factors, including the concentrations of the target contaminant, reductant, and catalyst and suspension ions on the dechlorination kinetics of PCE. Ninety five percent of the PCE was degraded by nFeS with Cbl(III) in 15 h. Cyclic voltammetry conducted with regard to the reductive dechlorination showed a higher redox potential of mackinawite under a high-pH condition (-1.01 V), suggesting that the oxidation state of the central cobalt ion in the cobalamin could be reduced to Cbl(I). The change of cobalamin species on the nFeS surface was verified under different pH conditions by UV-vis spectroscopy. The rate constant of PCE dechlorination increased from 0.1582 to 0.4284 h(-1) due to the increase in the nFeS content (2.085-20.85 g/L). As the concentration of Cbl(III) increased from 0 to 0.5 mM, the dechlorination kinetics of PCE was accelerated (0-1.4091 h(-1)) but reached a state of equilibrium from 0.5 to 1 mM. The increase in the initial PCE concentration (0.035-1.0 mM) slowed down the dechlorination kinetics (0.2036-0.0962 h(-1)). The dechlorination kinetics was enhanced by 1.5-11 times when 10 mM of ions (Na(+), K(+), Mg(2+), Ca(2+), CO3(2-), SO4(2-), and NO3(-)) were added, while an addition of HCO3 decelerated it by 10 times. This study can provide background knowledge pertaining to the PCE dechlorination by a natural reductant under a high-pH condition and the effect of environmental factors on the dechlorination kinetics for the development of novel remediation technologies.
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Affiliation(s)
- Sangwoo Kim
- Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Republic of Korea
| | - Taehyung Park
- Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Republic of Korea
| | - Woojin Lee
- Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Republic of Korea.
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10
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Amir A, Lee W. Enhanced reductive dechlorination of tetrachloroethene during reduction of cobalamin (III) by nano-mackinawite. JOURNAL OF HAZARDOUS MATERIALS 2012; 235-236:359-366. [PMID: 22939091 DOI: 10.1016/j.jhazmat.2012.08.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Revised: 08/03/2012] [Accepted: 08/06/2012] [Indexed: 06/01/2023]
Abstract
We demonstrated adsorption and reduction of cobalamin(III) (Co(III)) on nano-mackinawite (nFeS) surface and their impact on reductive dechlorination of tetrachloroethene (PCE). The adsorption of Co(III) on the nFeS surface followed Langmuir isotherm and the reduction of Co(III) provided different reactive surface chemical species on nFeS surface. Content of Fe(2+)S on nFeS surface decreased (45.9-14.5%) as Fe(2+)S was oxidized to Fe(3+)S and Fe(3+)O coupled with the surface reduction of Co(III) to cobalamin(II) (Co(II)). S(2-) and S(n)(2-) contents on the nFeS surface also decreased by 48.5% and 82.3%, respectively during the formation of sulfidecobalamin(II) (≡S(2-)Co(II)) by the reactive surface sulfur. PCE was fully degraded in nFeSCo(III) suspension at pH 8.3 in 120 h. The dechlorination kinetic rate constant of PCE in the nFeSCo(III) suspension (k(FeSCo(III))=0.188±0.003 h(-1)) was 145 times greater than that in nFeS suspension, showing a potential role of ≡S(2-)Co(II) as an electron transfer mediator to shuttle electrons for the enhanced reductive dechlorination. PCE was transformed to acetylene and 1,3-butadiene as major products via reductive β-elimination and isomerization reactions, respectively. The experimental findings can provide basic knowledge to identify a reaction mechanism for the enhanced reductive dechlorination of chlorinated organic by biogeochemical reactions possibly observed in natural reducing environments.
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Affiliation(s)
- Amnorzahira Amir
- Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-Gu, Daejeon 305-701, South Korea
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Cwiertny DM, Scherer MM. Abiotic Processes Affecting the Remediation of Chlorinated Solvents. SERDP/ESTCP ENVIRONMENTAL REMEDIATION TECHNOLOGY 2010. [DOI: 10.1007/978-1-4419-1401-9_4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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12
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Nelkenbaum E, Dror I, Berkowitz B. Reductive dechlorination of atrazine catalyzed by metalloporphyrins. CHEMOSPHERE 2009; 75:48-55. [PMID: 19150728 DOI: 10.1016/j.chemosphere.2008.11.074] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2008] [Revised: 11/20/2008] [Accepted: 11/20/2008] [Indexed: 05/27/2023]
Abstract
Atrazine (2-chloro-4-(ethylamine)-6-(isopropylamine)-s-triazine) is a widely used herbicide which is considered a persistent groundwater contaminant. Its selective transformation mediated by cobalt or nickel porphyrins was studied in aqueous solutions at room temperature and ambient pressure. Several metalloporphyrins were examined as catalysts for the reaction and all yielded the same reaction, transforming atrazine solely to the seldomly reported form 2,4-bis(ethylamine)-6-methyl-s-triazine. The reaction involves dechlorination and migration of a methyl group to yield a symmetric product. Nickel 5,10,15,20-tetrakis(1-methyl-4-pyridinio)porphyrin tetra(p-toluenesulfonate) (TMPyP) was activated by nanosized zero-valent iron (nZVI) while cobalt porphyrins (TMPyP, 5,10,15,20-tetrakis(4-hydroxyphenyl)-21H,23H-porphine-(TP(OH)P) and 4,4',4'',4'''-(porphine-5,10,15,20-tetrayl)tetrakis (benzenesulfonic acid)-(TBSP)) were activated by titanium(III) citrate as the electron donor. The effect of pH on atrazine transformation was demonstrated for the catalytic system of TP(OH)P-Co/Ti(III) citrate. Finally, a comparison of the reactivities of cobalt TMPyP and TP(OH)P was given and the differences discussed.
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Affiliation(s)
- Elza Nelkenbaum
- Department of Environmental Sciences and Energy Research, Weizmann Institute of Science, Rehovot 76100, Israel
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13
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Kliegman S, McNeill K. Dechlorination of chloroethylenes by cob(i)alamin and cobalamin model complexes. Dalton Trans 2008:4191-201. [DOI: 10.1039/b801679h] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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15
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Fraga R, Correia J, Keese R, Abrantes L. Immobilization of Vitamin B12 onto solid electrodes by electropolymerization of a catalyst-modified monomer. Electrochim Acta 2005. [DOI: 10.1016/j.electacta.2004.10.059] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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16
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Dror I, Schlautman MA. Cosolvent effect on the catalytic reductive dechlorination of PCE. CHEMOSPHERE 2004; 57:1505-14. [PMID: 15519395 DOI: 10.1016/j.chemosphere.2004.08.078] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2003] [Revised: 05/28/2004] [Accepted: 08/23/2004] [Indexed: 05/11/2023]
Abstract
Reductive dechlorination of chlorinated organic contaminants is an effective approach to treat this widespread group of environmentally hazardous substances. Metalloporphyrins can be used to catalyze reduction reactions by shuttling electrons from a reducing agent (electron donor) to chlorinated organic contaminants, thus rendering them to non-chlorinated acetylene, ethylene or ethane as major products. Iron, nickel and vanadium oxide tetraphenyl porphyrins (TPPs) were used as models of non-soluble metalloporphyrins that are common in subsurface environments, and hence may inflect on the ability to use natural ones. The effect of cosolvents on metalloporphyrins is demonstrated to switch the reduction of tetrachlorethylene (PCE) from no reaction to complete PCE transformation within 24 h and the production of final non-chlorinated compounds. Variations in product distributions for the different metalloporphyrins indicate that changes in the core metal can influence reaction rates and effective pathways. Furthermore, different cosolvents can generate varied product distributions, again suggesting that different pathways and/or rates are operative in the reduction reactions. Comparison of different cosolvent effects on PCE reduction using vitamin B12--a soluble natural metalloporphyrinogen--as the catalyst shows less pronounced differences between reactions in various cosolvent solutions versus only aqueous solution.
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Affiliation(s)
- Ishai Dror
- Department of Environmental Science and Energy Research, Weizmann Institute of Science, P.O. Box 26, Rehovot 76100, Israel.
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17
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Lee W, Batchelor B. Abiotic reductive dechlorination of chlorinated ethylenes by soil. CHEMOSPHERE 2004; 55:705-713. [PMID: 15013675 DOI: 10.1016/j.chemosphere.2003.11.033] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2003] [Revised: 10/20/2003] [Accepted: 11/13/2003] [Indexed: 05/24/2023]
Abstract
Abiotic reductive dechlorination of chlorinated ethylenes by soil in anaerobic environments was characterized to improve knowledge of the behavior of chlorinated ethylenes in natural systems, including systems modified to promote attenuation of contaminants. Target organics in the soil suspension reached sorption equilibrium in 2 days and the sorption isotherm of target organics was properly described by the linear sorption model. A modified Langmuir-Hinshelwood model was developed to describe the kinetics of reductive dechlorination of target organics by soil. The rate constants for the reductive dechlorination of chlorinated ethylenes at the reactive surfaces of reduced soils were found in the range between 0.055 (+/- 8.9%) and 2.60 (+/- 3.2%) day(-1). The main transformation products in reduced soil suspensions were C2 hydrocarbons. No chlorinated intermediates were observed at concentrations above detection limits. Five cycles of reduction of the soil followed by oxidation of the soil with trichloroethylene (TCE) did not affect the removal of TCE. The removal was affected by the reductants used and increased in the order: Fe(II) < dithionite < Fe(II) + dithionite.
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Affiliation(s)
- Woojin Lee
- Environment and Process Technology Division, Korea Institute of Science and Technology, P.O. Box 131, Cheongryang, Seoul 130-650, South Korea
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18
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He J, Sáez AE, Ela WP, Betterton EA, Arnold RG. Destruction of Aqueous-Phase Carbon Tetrachloride in an Electrochemical Reactor with a Porous Cathode. Ind Eng Chem Res 2004. [DOI: 10.1021/ie030591c] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jiahan He
- Department of Chemical and Environmental Engineering and Department of Atmospheric Sciences, University of Arizona, Tucson, Arizona 85721
| | - A. Eduardo Sáez
- Department of Chemical and Environmental Engineering and Department of Atmospheric Sciences, University of Arizona, Tucson, Arizona 85721
| | - Wendell P. Ela
- Department of Chemical and Environmental Engineering and Department of Atmospheric Sciences, University of Arizona, Tucson, Arizona 85721
| | - Eric A. Betterton
- Department of Chemical and Environmental Engineering and Department of Atmospheric Sciences, University of Arizona, Tucson, Arizona 85721
| | - Robert G. Arnold
- Department of Chemical and Environmental Engineering and Department of Atmospheric Sciences, University of Arizona, Tucson, Arizona 85721
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Pon G, Hyman MR, Semprini L. Acetylene inhibition of trichloroethene and vinyl chloride reductive dechlorination. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2003; 37:3181-3188. [PMID: 12901668 DOI: 10.1021/es026352i] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Kinetic studies reported here have shown that acetylene is a potent reversible inhibitor of reductive dehalogenation of trichloroethene (TCE) and vinyl chloride (VC) by a mixed dehalogenating anaerobic culture. The mixed culture was enriched from a contaminated site in Corvallis, OR, and exhibited methanogenic, acetogenic, and reductive dehalogenation activities. The H2-fed culture transformed TCE to ethene via cis-dichloroethene (c-DCE) and VC as intermediates. Batch kinetic studies showed acetylene reversibly inhibited reduction of both TCE and VC, and the levels of inhibition were strongly dependent on acetylene concentrations in both cases. Acetylene concentrations of 192 and 12 microM, respectively, were required to achieve 90% inhibition in rates of TCE and VC transformation at an aqueous concentration of 400 microM. Acetylene also inhibited methane production (90% inhibition at 48 microM) but did not inhibit H2-dependent acetate production. Mass balances conducted during the studies of VC inhibition showed that acetogenesis, VC transformation to ethene, and methane production were responsible for 52%, 47%, and 1% of the H2 consumption, respectively. The results indicate that halorespiration is the dominant process responsible for VC and TCE transformation and that dehalorespiring organisms are the target of acetylene inhibition. Acetylene has potential use as a reversible inhibitor to probe the biological activities of reductive dechlorination and methanogenesis. It can be added to inhibit reactions and then removed to permit reactions to proceed. Thus, it can be a powerful tool for investigating intrinsic and enhanced anaerobic remediation of chloroethenes at contaminated sites. The results also suggest that acetylene produced abiotically by reactions of chlorinated ethenes with zero-valent iron could inhibit the biological transformation of VC to ethene.
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Affiliation(s)
- George Pon
- Department of Civil, Construction and Environmental Engineering, Oregon State University, Corvallis, Oregon 97331, USA
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Dror I, Schlautman MA. Role of metalloporphyrin core metals in the mediated reductive dechlorination of tetrachloroethylene. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2003. [PMID: 12627638 DOI: 10.1002/etc.5620220309] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
A promising approach to abiotically dechlorinate a variety of chlorinated organic contaminants under reducing conditions is to utilize porphyrins or other tetrapyrrole macrocycles as electron transfer mediators/shuttles for catalyzing their reduction. In this study, various experimental approaches were used to elucidate the role of porphyrin core metals in the reductive dechlorination of tetrachloroethylene (PCE). The importance of specific core metals for the reactivity of a porphyrin and its mediated reaction mechanisms was demonstrated by inserting different metals into metallo tetrakis (N-methyl-4-4 pyridiniumyl) porphyrin (TMPyP). No PCE dechlorination was observed when the free-base (i.e., no core metal) and iron core metal forms of TMPyP were utilized. When using nickel or cobalt TMPyP, reductive dechlorination of PCE occurred but appeared to follow different pathways for the two metals based on product analyses. Physical (e.g., steric) considerations suggest that direct contact between a porphyrin core metal and PCE may be limited and therefore that the entire metalloporphyrin molecule should be viewed as a functional system in which the organic macrocycle has an active part in reductive dechlorination reactions. This view is supported by the fact that slight changes in the functional groups on a porphyrin macrocycle, particularly those far removed from the core metal itself, greatly affected the reactivity and mechanism of the porphyrin. Solution conditions also had a major effect on porphyrin reactivities, to the extent that a nonreactive metalloporphyrin could be activated merely by adjusting the pH of the solution or by adding a small amount of cosolvent. The collective results of this study suggest that fine tuning of naturally occurring metalloporphyrin complexes and/or their environments can enhance the catalyzed detoxification of chlorinated contaminants in many natural and engineered environmental systems.
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Affiliation(s)
- Ishai Dror
- Department of Agricultural and Biological Engineering, Clemson University, Clemson, South Carolina 29634-0357, USA
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Lee W, Batchelor B. Abiotic reductive dechlorination of chlorinated ethylenes by iron-bearing soil minerals. 2. Green rust. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2002; 36:5348-54. [PMID: 12521160 DOI: 10.1021/es0258374] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Abiotic reductive dechlorination of chlorinated ethylenes by the sulfate form of green rust (GR(SO4)) was examined in batch reactors. Dechlorination kinetics were described by a modified Langmuir-Hinshelwood model. The rate constant for reductive dechlorination of chlorinated ethylenes at reactive GR(SO4) surfaces was in the range of 0.592 (+/-4.4%) to 1.59 (+/-6.3%) day(-1). The specific reductive capacity of GR(SO4) for target organics was in the range of 9.86 (+/-10.1%) to 18.0 (+/-4.3%) microM/g and sorption coefficient was in the range of 0.53 (+/-2.4%) to 1.22 (+/-4.3%) mM(-1). Surface area-normalized pseudo-first-order initial rate constants for chlorinated ethylenes by GR(SO4) were 3.4 to 8.2 times greater than those by pyrite. Chlorinated ethylenes were mainly transformed to acetylene, and no detectable amounts of chlorinated intermediates were observed. The rate constants for the reductive dechlorination of trichloroethylene (TCE) increased as pH increased (6.8 to 10.1) but were independent of solid concentration and initial TCE concentration. Magnetite and/or maghemite were produced by the oxidation of GR(SO4) by TCE. These findings are relevant to the understanding of the role of abiotic reductive dechlorination during natural attenuation in environments that contain GR(SO4).
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Affiliation(s)
- Woojin Lee
- Environmental Science Research Center, School of Public and Environmental Affairs, Indiana University, Bloomington, Indiana 47405, USA.
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Lee W, Batchelor B. Abiotic reductive dechlorination of chlorinated ethylenes by iron-bearing soil minerals. 1. Pyrite and magnetite. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2002; 36:5147-54. [PMID: 12523432 DOI: 10.1021/es025836b] [Citation(s) in RCA: 150] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Abiotic reductive dechlorination of chlorinated ethylenes (tetrachloroethylene (PCE), trichloroethylene (TCE), cis-dichloroethylene (cis-DCE), and vinyl chloride (VC)) by pyrite and magnetite was characterized in a batch reactor system. Dechlorination kinetics was adequately described by a modified Langmuir-Hinshelwood model that includes the effect of a decreasing reductive capacity of soil mineral. The kinetic rate constant for the reductive dechlorination of target organics at reactive sites of soil minerals was in the range of 0.185 (+/- 0.023) to 1.71 (+/- 0.06) day(-1). The calculated specific reductive capacity of soil minerals for target organics was in the range of 0.33 (+/- 0.02) to 2.26 (+/- 0.06) microM/g and sorption coefficient was in the range of 0.181 (+/- 0.006) to 0.7 (+/- 0.022) mM(-1). Surface area-normalized pseudo-first-order initial rate constants for target organics by pyrite were found to be 23.5 to 40.3 times greater than those by magnetite. Target organics were mainly transformed to acetylene and small amount of chlorinated intermediates, which suggests that beta-elimination was the main dechlorination pathway. The dechlorination of VC followed a hydrogenolysis pathway to produce ethylene and ethane. The addition of Fe(II) increased the dechlorination rate of cis-DCE and VC in magnetite suspension by nearly a factor of 10. The results obtained in this research provide basic knowledge to better predict the fate of chlorinated ethylenes and to understand the potential of abiotic processes in natural attenuation.
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Affiliation(s)
- Woojin Lee
- Environmental Science Research Center, School of Public and Environmental Affairs, Indiana University, Bloomington, Indiana 47405, USA.
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Alonso F, Beletskaya IP, Yus M. Metal-mediated reductive hydrodehalogenation of organic halides. Chem Rev 2002; 102:4009-91. [PMID: 12428984 DOI: 10.1021/cr0102967] [Citation(s) in RCA: 609] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Francisco Alonso
- Departamento de Química Orgánica, Facultad de Ciencias, Universidad de Alicante, Apdo 99, E-03080 Alicante, Spain
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Koons BW, Baeseman JL, Novak PJ. Investigation of cell exudates active in carbon tetrachloride and chloroform degradation. Biotechnol Bioeng 2001; 74:12-7. [PMID: 11353406 DOI: 10.1002/bit.1090] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Contamination of groundwater by chlorinated solvents such as carbon tetrachloride (CCl4) and chloroform (CHCl3) is a widespread problem. The cell exudates from the methanogen Methanosarcina thermophila are active in the degradation of CCl4 and CHCl3. This research was performed to characterize these exudates. Examination of the influence of pH indicated that activity was greater under alkaline conditions. Rapid CCl4 degradation occurred from 35-65 degrees C, with first-order degradation rate coefficients increasing as temperature increased. It was found that proteins were not responsible for CCl4 degradation. The active agents in the cell exudates were <10 kDa in size, with degradation activity present in both 1-10 kDa and <1 kDa size ranges. Upon purification of the <10 kDa size range of the cell exudates on a C(18) chromatography column, 17 fractions (out of 100) degraded >50% of the added CCl4 in 8 h. These 17 fractions were pooled into three samples based on their elution time from the C(18) column. One of these pooled samples contained elevated levels of cobalt, zinc, and iron, at 2, 3, and 13 times the levels measured in similarly fractionated and pooled samples of medium, respectively. The UV-visible spectrum of this pooled sample had an absorption maximum at 560-580 nm, which is similar to the absorption maxima of heme (approximately 550 and 575 nm). The two other pooled samples contained elevated levels of zinc at 11 and 22 times the concentration measured in similarly fractionated and pooled samples of medium, respectively, and also contained very low levels of nickel, cobalt, and iron. This research suggests that the cell exudates from M. thermophila contain porphorinogen-type molecules capable of dechlorination, possibly excreted corrinoids, hemes, and zinc-containing molecules.
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Affiliation(s)
- B W Koons
- Department of Civil Engineering, University of Minnesota, 122 Civil Engineering Building, 500 Pillsbury Drive S.E., Minneapolis, MN 55455-0220, USA
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Hashsham SA, Freedman DL. Enhanced biotransformation of carbon tetrachloride by Acetobacterium woodii upon addition of hydroxocobalamin and fructose. Appl Environ Microbiol 1999; 65:4537-42. [PMID: 10508086 PMCID: PMC91604 DOI: 10.1128/aem.65.10.4537-4542.1999] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The objective of this study was to evaluate the effect of hydroxocobalamin (OH-Cbl) on transformation of high concentrations of carbon tetrachloride (CT) by Acetobacterium woodii (ATCC 29683). Complete transformation of 470 microM (72 mg/liter [aqueous]) CT was achieved by A. woodii within 2.5 days, when 10 microM OH-Cbl was added along with 25.2 mM fructose. This was approximately 30 times faster than A. woodii cultures (live or autoclaved) and medium that did not receive OH-Cbl and 5 times faster than those controls that did receive OH-Cbl, but either live A. woodii or fructose was missing. CT transformation in treatments with only OH-Cbl was indicative of the important contribution of nonenzymatic reactions. Besides increasing the rate of CT transformation, addition of fructose and OH-Cbl to live cultures increased the percentage of [(14)C]CT transformed to (14)CO(2) (up to 31%) and (14)C-labeled soluble materials (principally L-lactate and acetate), while decreasing the percentage of CT reduced to chloroform and abiotically transformed to carbon disulfide. (14)CS(2) represented more than 35% of the [(14)C]CT in the presence of reduced medium and OH-Cbl. Conversion of CT to CO was a predominant pathway in formation of CO(2) in the presence of live cells and added fructose and OH-Cbl. These results indicate that the rate and distribution of products during cometabolic transformation of CT by A. woodii can be improved by the addition of fructose and OH-Cbl.
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Affiliation(s)
- S A Hashsham
- Center for Microbial Ecology and Department of Civil and Environmental Engineering, Michigan State University, E. Lansing, Michigan 48824, USA.
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Lee CH, Lewis TA, Paszczynski A, Crawford RL. Identification of an extracellular agent [correction of catalyst] of carbon tetrachloride dehalogenation from Pseudomonas stutzeri strain KC as pyridine-2, 6-bis(thiocarboxylate). Biochem Biophys Res Commun 1999; 261:562-6. [PMID: 10441466 DOI: 10.1006/bbrc.1999.1077] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Pseudomonas stutzeri strain KC was originally characterized as having, under iron-limiting conditions, novel carbon tetrachloride (CCl(4)) dehalogenation activity, specifically, a net conversion of CCl(4) to CO(2). The exact pathway and reaction mechanisms are unknown, but chloroform is not an intermediate and thiophosgene and phosgene have been identified as intermediates in trapping experiments. Previous work by others using cell-free preparations has shown that cell-free culture supernatants that have been passed through a low-molecular-weight cutoff membrane can confer rapid CCl(4) transformation ability upon cultures of bacteria which otherwise show little or no reactivity toward CCl(4). We used a cell-free assay system to monitor the complete purification of compounds showing CCl(4) degradation activity elaborated by iron-limited cultures of strain KC. Electrospray tandem mass spectroscopy, NMR spectroscopy, and comparisons with synthetic material have identified pyridine-2,6-bis(thiocarboxylate) as a metabolite of strain KC which has CCl(4) transformation activity in the presence of chemical reductants, e.g., titanium[III] citrate or dithiothreitiol, or actively growing bacterial cultures.
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Affiliation(s)
- C H Lee
- Department of Microbiology, Molecular Biology, and Biochemistry, University of Idaho, Moscow, Idaho, 83844-1052, USA
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Degradation and Fate of Carbon Tetrachloride in Unadapted Methanogenic Granular Sludge. Appl Environ Microbiol 1998; 64:2350-6. [PMID: 9647798 PMCID: PMC106394 DOI: 10.1128/aem.64.7.2350-2356.1998] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The potential of granular sludge from upflow anaerobic sludge blanket (UASB) reactors for bioremediation of chlorinated pollutants was evaluated by using carbon tetrachloride (CT) as a model compound. Granular sludges cultivated in UASB reactors on methanol, a volatile fatty acid mixture, or sucrose readily degraded CT supplied at a concentration of 1,500 nmol/batch (approximately 10 µM) without any prior exposure to organohalogens. The maximum degradation rate was 1.9 µmol of CT g of volatile suspended solids-1 day-1. The main end products of CT degradation were CO2 and Cl-, and the yields of these end products were 44 and 68%, respectively, of the initial amounts of [14C]CT and CT-Cl. Lower chlorinated methanes accumulated in minor amounts temporarily. Autoclaved (dead) sludges were capable of degrading CT at rates two- to threefold lower than those for living sludges, indicating that abiotic processes (mediated by cofactors or other sludge components) played an important role in the degradation observed. Reduced components in the autoclaved sludge were vital for CT degradation. A major part (51%) of the CT was converted abiotically to CS2. The amount of CO2 produced (23%) was lower and the amount of Cl- produced (86%) was slightly higher with autoclaved sludge than with living sludge. Both living and autoclaved sludges could degrade chloroform. However, only living sludge degraded dichloromethane and methylchloride. These results indicate that reductive dehalogenation, which was mediated better by living sludge than by autoclaved sludge, is only a minor pathway for CT degradation. The main pathway involves substitutive and oxidative dechlorination reactions that lead to the formation of CO2. Granular sludge, therefore, has outstanding potential for gratuitous dechlorination of CT to safe end products.
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