Trichlorobenzene

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Lorenz Adrian - One of the best experts on this subject based on the ideXlab platform.

  • Enrichment of hexachlorobenzene and 1,3,5-Trichlorobenzene transforming bacteria from sediments in Germany and Vietnam
    Biodegradation, 2013
    Co-Authors: Tran Hoa Duan, Lorenz Adrian
    Abstract:

    Bacterial cultures were enriched from sediments in Germany and Vietnam reductively dechlorinating hexachlorobenzene and the highly persistent 1,3,5-Trichlorobenzene to monochlorobenzene. The main products of the reductive dechlorination of hexachlorobenzene were monochlorobenzene and dichlorobenzenes (1,2-; 1,3- and 1,4-dichlorobenzene) while no Trichlorobenzenes accumulated. For the reductive dechlorination of 1,3,5-Trichlorobenzene with the mixed culture from Vietnam sediment, 1,3- dichlorobenzene and monochlorobenzene were produced as intermediate and final end-product, respectively. The pattern of dechlorination did not change when the cultures were repeatedly exposed to oxygen over seven transfers demonstrating oxygen tolerance of the dechlorinating bacteria. However, reductive dechlorination of 1,3,5-Trichlorobenzene was inhibited by vancomycin at a concentration of 5 mg L^−1. Vancomycin delayed reductive dechlorination of hexachlorobenzene in mixed cultures by about 6 months. When repeatedly applied, vancomycin completely abolished the ability of the mixed culture to transform hexachlorobenzene. Sensitivity to vancomycin and insensitivity to brief exposure of oxygen indicates that the dechlorinating bacteria in the mixed cultures did not belong to the genus Dehalococcoides .

  • identification of a chlorobenzene reductive dehalogenase in dehalococcoides sp strain cbdb1
    Applied and Environmental Microbiology, 2007
    Co-Authors: Lorenz Adrian, Jan Rahnenfuhrer, Johan Gobom, Tina Holscher
    Abstract:

    A chlorobenzene reductive dehalogenase of the anaerobic dehalorespiring bacterium Dehalococcoides sp. strain CBDB1 was identified. Due to poor biomass yields, standard protein isolation procedures were not applicable. Therefore, cell extracts from cultures grown on Trichlorobenzenes were separated by native polyacrylamide gel electrophoresis and analyzed directly for chlorobenzene reductive dehalogenase activity within gel fragments. Activity was found in a single band, even though electrophoretic separation was performed under aerobic conditions. Matrix-assisted laser desorption ionization mass spectrometry (MALDI MS) and nano-liquid chromatography-MALDI MS analysis of silver-stained replicas of the active band on native polyacrylamide gels identified a protein product of the cbdbA84 gene, now called cbrA. The cbdbA84 gene is one of 32 reductive dehalogenase homologous genes present in the genome of strain CBDB1. The chlorobenzene reductive dehalogenase identified in our study represents a member of the family of corrinoid/iron-sulfur cluster-containing reductive dehalogenases. No orthologs of cbdbA84 were found in the completely sequenced genomes of Dehalococcoides sp. strains 195 and BAV1 nor among the genes amplified from Dehalococcoides sp. strain FL2 or mixed cultures containing Dehalococcoides. Another dehalogenase homologue (cbdbA80) was expressed in cultures that contained 1,2,4-Trichlorobenzene, but its role is unclear. Other highly expressed proteins identified with our approach included the major subunit of a protein annotated as formate dehydrogenase, transporter subunits, and a putative S-layer protein.

  • Stable carbon isotope fractionation during aerobic and anaerobic transformation of Trichlorobenzene
    FEMS microbiology ecology, 2004
    Co-Authors: Christian Griebler, Lorenz Adrian, Rainer U. Meckenstock, Hans H. Richnow
    Abstract:

    Fractionation of stable carbon isotopes upon degradation of Trichlorobenzenes was studied under aerobic and anaerobic conditions. Mineralization of 1,2,4-Trichlorobenzene by the aerobic strain Pseudomonas sp. P51 which uses a dioxygenase for the initial enzymatic reaction was not accompanied by a significant isotope fractionation. In contrast, reductive dehalogenation by the anaerobic strain Dehalococcoides sp. strain CBDB1 revealed average isotope enrichment factors (η) between −3.1 and −3.7 for 1,2,3- and 1,2,4-Trichlorobenzene, respectively. The significant isotope fractionation during reductive dehalogenation would allow tracing the in situ biodegradation of halogenated benzenes in contaminated anoxic aquifers, whereas the lack of isotope fractionation during aerobic transformation limits the use of this approach in oxic environments.

  • Dehalorespiration with hexachlorobenzene and pentachlorobenzene by Dehalococcoides sp. strain CBDB1
    Archives of Microbiology, 2003
    Co-Authors: Gopalakrishnan Jayachandran, Helmut Gorisch, Lorenz Adrian
    Abstract:

    The chlororespiring anaerobe Dehalococcoides sp. strain CBDB1 used hexachlorobenzene and pentachlorobenzene as electron acceptors in an energy-conserving process with hydrogen as electron donor. Previous attempts to grow Dehalococcoides sp. strain CBDB1 with hexachlorobenzene or pentachlorobenzene as electron acceptors failed if these compounds were provided as solutions in hexadecane. However, Dehalococcoides sp. strain CBDB1 was able to grow with hexachlorobenzene or pentachlorobenzene when added in crystalline form directly to cultures. Growth of Dehalococcoides sp. strain CBDB1 by dehalorespiration resulted in a growth yield ( Y ) of 2.1±0.24 g protein/mol Cl^− released with hexachlorobenzene as electron acceptor; with pentachlorobenzene, the growth yield was 2.9±0.15 g/mol Cl^−. Hexachlorobenzene was reductively dechlorinated to pentachlorobenzene, which was converted to a mixture of 1,2,3,5- and 1,2,4,5-tetrachlorobenzene. Formation of 1,2,3,4-tetrachlorobenzene was not detected. The final end-products of hexachlorobenzene and pentachlorobenzene dechlorination were 1,3,5-Trichlorobenzene, 1,3- and 1,4-dichlorobenzene, which were formed in a ratio of about 3:2:5. As reported previously, Dehalococcoides sp. strain CBDB1 converted 1,2,3,5-tetrachlorobenzene exclusively to 1,3,5-Trichlorobenzene, and 1,2,4,5-tetrachlorobenzene exclusively to 1,2,4-Trichlorobenzene. The organism therefore catalyzes two different pathways to dechlorinate highly chlorinated benzenes. In the route leading to 1,3,5-Trichlorobenzene, only doubly flanked chlorine substituents were removed, while in the route leading to 1,3-and 1,4-dichlorobenzene via 1,2,4-Trichlorobenzene singly flanked chlorine substituents were also removed. Reductive dehalogenase activity measurements using whole cells pregrown with different chlorobenzene congeners as electron acceptors indicated that different reductive dehalogenases might be induced by the different electron acceptors. To our knowledge, this is the first report describing reductive dechlorination of hexachlorobenzene and pentachlorobenzene via dehalorespiration by a pure bacterial culture.

  • Physiological Characterization of a Bacterial Consortium Reductively Dechlorinating 1,2,3- and 1,2,4-Trichlorobenzene
    Applied and environmental microbiology, 1998
    Co-Authors: Lorenz Adrian, Werner Manz, Ulrich Szewzyk, Helmut Gorisch
    Abstract:

    A bacterial mixed culture reductively dechlorinating Trichlorobenzenes was established in a defined, synthetic mineral medium without any complex additions and with pyruvate as the carbon and energy source. The culture was maintained over 39 consecutive transfers of small inocula into fresh media, enriching the dechlorinating activity. In situ probing with fluorescence-labeled rRNA-targeted oligonucleotide probes revealed that two major subpopulations within the microbial consortium were phylogenetically affiliated with a sublineage within the Desulfovibrionaceae and the gamma subclass of Proteobacteria. The bacterial consortium grew by fermentation of pyruvate, forming acetate, propionate, CO2, formate, and hydrogen. Acetate and propionate supported neither the reduction of Trichlorobenzenes nor the reduction of sulfate when sulfate was present. Hydrogen and formate were used for sulfate reduction to sulfide. Sulfate strongly inhibited the reductive dechlorination of Trichlorobenzenes. However, when sulfate was depleted in the medium due to sulfate reduction, dechlorination of Trichlorobenzenes started. Similar results were obtained when sulfite was present in the cultures. Molybdate at a concentration of 1 mM strongly inhibited the dechlorination of Trichlorobenzenes. Cultures supplied with molybdate plus sulfate did not reduce sulfate, but dechlorination of Trichlorobenzenes occurred. Supplementation of electron-depleted cultures with various electron sources demonstrated that formate was used as a direct electron donor for reductive dechlorination, whereas hydrogen was not.

Dongyang Wei - One of the best experts on this subject based on the ideXlab platform.

  • competitive sorption between 1 2 4 Trichlorobenzene tetrachloroethene and 1 2 4 5 tetrachlorobenzene by soils sediments from south china
    Science of The Total Environment, 2013
    Co-Authors: Yuehong Shu, Peihong Liu, Qiuyun Zhang, Dongyang Wei
    Abstract:

    1,2,4-Trichlorobenzene (1,2,4-TCB) and tetrachloroethene (PCE) were chosen to study their competitive effect on 1,2,4,5-tetrachlorobenzene (1,2,4,5-TeCB) sorption by three soils/sediments from South China with different fractions of natural organic matter (NOM) employing a batch technique. Results showed that cosolutes 1,2,4-Trichlorobenzene and tetrachloroethene exhibited apparent competition against 1,2,4,5-tetrachlorobenzene in all of the three sediments. 1,2,4-Trichlorobenzene was more effective competitor than tetrachloroethene because the structure of 1,2,4-TCB is very close to that of 1,2,4,5-TeCB. Furthermore, the extent of competition depended on the rigidity of sediment NOM matrixes. The more reduced and condensed the matrixes are, the larger extent of competitive effect would the corresponding sediment show at a given sorbed volume of competitor.

  • Competitive sorption between 1,2,4-Trichlorobenzene/tetrachloroethene and 1,2,4,5-tetrachlorobenzene by soils/sediments from South China
    Science of The Total Environment, 2013
    Co-Authors: Yuehong Shu, Peihong Liu, Qiuyun Zhang, Dongyang Wei
    Abstract:

    1,2,4-Trichlorobenzene (1,2,4-TCB) and tetrachloroethene (PCE) were chosen to study their competitive effect on 1,2,4,5-tetrachlorobenzene (1,2,4,5-TeCB) sorption by three soils/sediments from South China with different fractions of natural organic matter (NOM) employing a batch technique. Results showed that cosolutes 1,2,4-Trichlorobenzene and tetrachloroethene exhibited apparent competition against 1,2,4,5-tetrachlorobenzene in all of the three sediments. 1,2,4-Trichlorobenzene was more effective competitor than tetrachloroethene because the structure of 1,2,4-TCB is very close to that of 1,2,4,5-TeCB. Furthermore, the extent of competition depended on the rigidity of sediment NOM matrixes. The more reduced and condensed the matrixes are, the larger extent of competitive effect would the corresponding sediment show at a given sorbed volume of competitor.

Matthew K. O. Lee - One of the best experts on this subject based on the ideXlab platform.

  • Isolation and Characterization of Dehalobacter sp. Strain TeCB1 Including Identification of TcbA: A Novel Tetra- and Trichlorobenzene Reductive Dehalogenase.
    Frontiers in microbiology, 2017
    Co-Authors: Ricardo Alfán-guzmán, Haluk Ertan, Mike Manefield, Matthew K. O. Lee
    Abstract:

    Dehalobacter sp. strain TeCB1 was isolated from groundwater near Sydney, Australia that is polluted with a range of organochlorines. The isolated strain is able to grow by reductive dechlorination of 1,2,4,5-tetrachlorobenzene to 1,3- and 1,4-dichlorobenzene with 1,2,4-Trichlorobenzene being the intermediate daughter product. Transient production of 1,2-dichlorobenzene was detected with subsequent conversion to monochlorobenzene. The dehalogenation capability of strain TeCB1 to respire 23 alternative organochlorines was examined and shown to be limited to the use of 1,2,4,5-tetrachlorobenzene and 1,2,4-Trichlorobenzene. Growth on 1,2,4-Trichlorobenzene resulted in the production of predominantly 1,3- and 1,4-dichlorobenzene. The inability of strain TeCB1 to grow on 1,2-dichlorobenzene indicated that the production of monochlorobenzene during growth on 1,2,4,5-tetarchlorobezene was cometabolic. The annotated genome of strain TeCB1 contained only one detectable 16S rRNA gene copy and genes for 23 full-length and one truncated Reductive Dehalogenase (RDase) homologs, five unique to strain TeCB1. Identification and functional characterization of the 1,2,4,5-tetrachlorobenzene and 1,2,4-Trichlorobenzene RDase (TcbA) was achieved using native-PAGE coupled with liquid chromatography tandem mass spectrometry and. Interestingly, TcbA showed higher amino acid identity with tetrachloroethene reductases PceA (95% identity) from Dehalobacter restrictus PER-K23 and Desulfitobacterium hafniense Y51 than with the only other chlorinated benzene reductase (i.e. CbrA (30% identity)) functionally characterized to date.

Maria Papadaki - One of the best experts on this subject based on the ideXlab platform.

  • Characterization and catalytic properties of niobia supported nickel catalysts in the hydrodechlorination of 1,2,4-Trichlorobenzene
    Journal of Molecular Catalysis A-chemical, 2004
    Co-Authors: Komandur V. R. Chary, Katar Sri Lakshmi, Kamaraju Seetha Rama Rao, Pendyala Venkat Ramana Rao, Maria Papadaki
    Abstract:

    Abstract A series of nickel (2–15 wt.%) catalysts supported on niobia were prepared. Their catalytic efficiency in the vapour phase hydrodechlorination of 1,2,4-Trichlorobenzene was studied. The catalyst samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), temperature programmed desorption of hydrogen (TPD), temperature programmed reduction (TPR) and hydrogen chemisorption method. Hydrogen chemisorption studies suggest that the hydrogen spillover culminates at 6 wt.% of Ni/Nb 2 O 5 . The partial hydrodechlorination ability of 6 wt.% Ni/Nb 2 O 5 was also found to be the highest. Niobia supported nickel catalysts were found to be highly active for the partial hydrodechlorination of 1,2,4-Trichlorobenzene. It was also found that the catalytic properties are related to dispersion of nickel on niobium oxide.

  • Hydrodechlorination of 1,2,4-Trichlorobenzene over niobia supported nickel catalysts
    Catalysis Communications, 2003
    Co-Authors: Komandur V. R. Chary, Katar Sri Lakshmi, Mamidanna R.v.s. Murthy, Kamaraju Seetha Rama Rao, Maria Papadaki
    Abstract:

    A series of nickel (2–15 wt%) catalysts supported on niobia were prepared. Their catalytic efficiency in the vapour phase hydrodechlorination of 1,2,4-Trichlorobenzene was studied. The catalyst samples were characterized by X-ray diffraction (XRD), temperature programmed reduction (TPR) and hydrogen chemisorption methods. Hydrogen chemisorption studies suggest that the hydrogen spillover culminates at 6 wt% of Ni/Nb2O5. The partial hydrodechlorination ability of 6 wt% Ni/Nb2O5 was also found to be the highest. Niobia supported nickel catalysts were found to be highly active for the partial hydrodechlorination of 1,2,4-Trichlorobenzene. It was also found that the catalytic properties are related to dispersion of nickel on niobium oxide.

Yuehong Shu - One of the best experts on this subject based on the ideXlab platform.

  • competitive sorption between 1 2 4 Trichlorobenzene tetrachloroethene and 1 2 4 5 tetrachlorobenzene by soils sediments from south china
    Science of The Total Environment, 2013
    Co-Authors: Yuehong Shu, Peihong Liu, Qiuyun Zhang, Dongyang Wei
    Abstract:

    1,2,4-Trichlorobenzene (1,2,4-TCB) and tetrachloroethene (PCE) were chosen to study their competitive effect on 1,2,4,5-tetrachlorobenzene (1,2,4,5-TeCB) sorption by three soils/sediments from South China with different fractions of natural organic matter (NOM) employing a batch technique. Results showed that cosolutes 1,2,4-Trichlorobenzene and tetrachloroethene exhibited apparent competition against 1,2,4,5-tetrachlorobenzene in all of the three sediments. 1,2,4-Trichlorobenzene was more effective competitor than tetrachloroethene because the structure of 1,2,4-TCB is very close to that of 1,2,4,5-TeCB. Furthermore, the extent of competition depended on the rigidity of sediment NOM matrixes. The more reduced and condensed the matrixes are, the larger extent of competitive effect would the corresponding sediment show at a given sorbed volume of competitor.

  • Competitive sorption between 1,2,4-Trichlorobenzene/tetrachloroethene and 1,2,4,5-tetrachlorobenzene by soils/sediments from South China
    Science of The Total Environment, 2013
    Co-Authors: Yuehong Shu, Peihong Liu, Qiuyun Zhang, Dongyang Wei
    Abstract:

    1,2,4-Trichlorobenzene (1,2,4-TCB) and tetrachloroethene (PCE) were chosen to study their competitive effect on 1,2,4,5-tetrachlorobenzene (1,2,4,5-TeCB) sorption by three soils/sediments from South China with different fractions of natural organic matter (NOM) employing a batch technique. Results showed that cosolutes 1,2,4-Trichlorobenzene and tetrachloroethene exhibited apparent competition against 1,2,4,5-tetrachlorobenzene in all of the three sediments. 1,2,4-Trichlorobenzene was more effective competitor than tetrachloroethene because the structure of 1,2,4-TCB is very close to that of 1,2,4,5-TeCB. Furthermore, the extent of competition depended on the rigidity of sediment NOM matrixes. The more reduced and condensed the matrixes are, the larger extent of competitive effect would the corresponding sediment show at a given sorbed volume of competitor.