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H. J. Rehm - One of the best experts on this subject based on the ideXlab platform.
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Degradation of 2-Chloroethanol by free and immobilized Pseudomonas putida US 2
Applied Microbiology and Biotechnology, 1995Co-Authors: Monika Knippschild, H. J. RehmAbstract:The degradation of 2-Chloroethanol by Pseudomonas putida US 2 was investigated in shaking flasks, air-bubble columns and packed-bed fermenters by free cells, calcium-alginate-entrapped cells and on cells on granular clay adsorbed. Entrapped cells tolerated increasing concentrations of 2-Chloroethanol better than free cells. Their maximum degradative activity could be observed at 34°C and pH 7.0. The degradation of 2-Chloroethanol leads to a decrease of pH and to a stagnation of mineralization, particularly with free or entrapped cells. Following the stabilization of pH, supplementation with succinate resulted in a complete degradation of higher 2-Chloroethanol concentrations. Less 2-Chloroethanol was degraded in air-bubble columns and larger amounts in packed-bed fermenters. 2-Chloroethanol was mineralized faster by free or entrapped P. putida US 2 than by adsorbed cells, which, on the other hand, were able to remove higher concentrations of the compound. The results with P. putida US 2 are a good indication that this microorganism could be used in waste-water treatment and soil-decontamination systems.
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Biodegradation of 2-Chloroethanol by freely suspended and adsorbed immobilized Pseudomonas putida US2 in soil.
Applied Microbiology and Biotechnology, 1995Co-Authors: C. Overmeyer, H. J. RehmAbstract:The degradation of 2-Chloroethanol by Pseudomonas putida US2 was investigated in batch, repeated batch and continuous cultures especially in a packed-bed fermenter with sand. The degradation of 2-Chloroethanol was connected with a release of protons, which led to a decrease of the pH in the medium. Higher initial concentration than 25 mM 2-Chloroethanol were not degraded completely because they entailed a decrease of the pH to 5.0, which inhibited further growth and degradation. P. putida US2 showed a typical repression of catabolites and diauxic growth with succinate as cosubstrate. The addition of succinate as a second substrate caused a decrease in degradation of 2-Chloroethanol. Activated sludge added to adsorbed cultures in a continuous fermentation did not lead to a decrease in metabolic activity. After 2 weeks of continuous cultivation the specialized strain could be retained.
Jan Gerritse - One of the best experts on this subject based on the ideXlab platform.
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Degradation pathway of 2-Chloroethanol in Pseudomonas stutzeri strain JJ under denitrifying conditions
Archives of Microbiology, 2004Co-Authors: J.a. Dijk, Jan Gerritse, Gosse Schraa, Alfons J M StamsAbstract:The pathway of 2-Chloroethanol degradation in the denitrifying Pseudomonas stutzeri strain JJ was investigated. In cell-free extracts, activities of a phenazine methosulfate (PMS)-dependent Chloroethanol dehydrogenase, an NAD-dependent chloroacetaldehyde dehydrogenase, and a chloroacetate dehalogenase were detected. This suggested that the 2-Chloroethanol degradation pathway in this denitrifying strain is the same as found in aerobic bacteria that degrade Chloroethanol. Activity towards primary alcohols, secondary alcohols, diols, and other chlorinated alcohols could be measured in cell-free extracts with Chloroethanol dehydrogenase (CE-DH) activity. PMS and phenazine ethosulfate (PES) were used as primary electron acceptors, but not NAD, NADP or ferricyanide. Cells of strain JJ cultured in a continuous culture under nitrate limitation exhibited Chloroethanol dehydrogenase activity that was a 12 times higher than in cells grown in batch culture. However, under Chloroethanol-limiting conditions, CE-DH activity was in the same range as in batch culture. Cells grown on ethanol did not exhibit CE-DH activity. Instead, NAD-dependent ethanol dehydrogenase (E-DH) activity and PMS-dependent E-DH activity were detected.
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anaerobic oxidation of 2 Chloroethanol under denitrifying conditions by pseudomonas stutzeri strain jj
Applied Microbiology and Biotechnology, 2003Co-Authors: J.a. Dijk, Gosse Schraa, Alfons J M Stams, Hendrik Ballerstedt, J A M De Bont, Jan GerritseAbstract:A bacterium that uses 2-Chloroethanol as sole energy and carbon source coupled to denitrification was isolated from 1,2-dichloroethane-contaminated soil. Its 16 S rDNA sequence showed 98% similarity with the type strain of Pseudomonas stutzeri (DSM 5190) and the isolate was tentatively identified as Pseudomonas stutzeri strain JJ. Strain JJ oxidized 2-Chloroethanol completely to CO(2) with NO(3)(- )or O(2) as electron acceptor, with a preference for O(2) if supplied in combination. Optimum growth on 2-Chloroethanol with nitrate occurred at 30 degrees C with a mu(max) of 0.14 h(-1) and a yield of 4.4 g protein per mol 2-Chloroethanol metabolized. Under aerobic conditions, the mu(max) was 0.31 h(-1). NO(2)(-) also served as electron acceptor, but reduction of Fe(OH)(3), MnO(2), SO(4)(2-), fumarate or ClO(3)(-) was not observed. Another chlorinated compound used as sole energy and carbon source under aerobic and denitrifying conditions was chloroacetate. Various different bacterial strains, including some closely related Pseudomonas stutzeri strains, were tested for their ability to grow on 2-Chloroethanol as sole energy and carbon source under aerobic and denitrifying conditions, respectively. Only three strains, Pseudomonas stutzeri strain LMD 76.42, Pseudomonas putida US2 and Xanthobacter autotrophicus GJ10, grew aerobically on 2-Chloroethanol. This is the first report of oxidation of 2-Chloroethanol under denitrifying conditions by a pure bacterial culture.
Paul L. Raston - One of the best experts on this subject based on the ideXlab platform.
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far infrared synchrotron spectroscopy and quantum chemical calculations of the potentially important interstellar molecule 2 Chloroethanol
Journal of Physical Chemistry A, 2019Co-Authors: Rebekah M. Soliday, Hayley Bunn, Isaiah Sumner, Paul L. RastonAbstract:The high brightness of the Australian synchrotron allowed for detailed spectra to be collected at high resolution (0.00096 cm-1) in the vicinity of the a/ b/ c-type ν19 band of 2-Chloroethanol, which involves O-H torsional motion about the C-O bond. A rovibrational analysis was performed for both chlorine isotopologues in the ν19 fundamental (centered at ∼344 cm-1) which involved the assignment of 7153 lines ( J ≤ 90, K a ≤ 41). A global fit to these lines in addition to 119 microwave lines ( J ≤ 29, K a ≤ 11) led to the determination of spectroscopic constants up to the sextic level in both the ground and excited states using Watson's A-reduction Hamiltonian. The constants agree well with those calculated at the anharmonic MP2/cc-pVTZ level and allow for spectroscopically accurate predictions of rotational transitions in the ground vibrational state to be made over a broad range of rotational energies ( TR < 1000 K). We explored the role that 2-Chloroethanol might play in interstellar molecular clouds by performing calculations on the substitution reaction between HCl and ethylene glycol, and the addition reaction between HCl and oxirane, all of which have been observed in Sagittarius B2(N) and are expected to play important roles in the chemistry that occurs on the icy mantles of interstellar dust grains. While both reactions have relatively high activation barriers, the HCl + oxirane reaction was found be much more exothermic; further calculations on it indicate that a water-like environment significantly reduces the barrier while slightly increasing its exothermicity. These results suggest that 2-Chloroethanol could be efficiently produced from the cosmic ray bombardment of common interstellar ices.
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Far-Infrared Synchrotron Spectroscopy and Quantum Chemical Calculations of the Potentially Important Interstellar Molecule, 2‑Chloroethanol
2019Co-Authors: Rebekah M. Soliday, Hayley Bunn, Isaiah Sumner, Paul L. RastonAbstract:The high brightness of the Australian synchrotron allowed for detailed spectra to be collected at high resolution (0.00096 cm–1) in the vicinity of the a/b/c-type ν19 band of 2-Chloroethanol, which involves O–H torsional motion about the C–O bond. A rovibrational analysis was performed for both chlorine isotopologues in the ν19 fundamental (centered at ∼344 cm–1) which involved the assignment of 7153 lines (J ≤ 90, Ka ≤ 41). A global fit to these lines in addition to 119 microwave lines (J ≤ 29, Ka ≤ 11) led to the determination of spectroscopic constants up to the sextic level in both the ground and excited states using Watson’s A-reduction Hamiltonian. The constants agree well with those calculated at the anharmonic MP2/cc-pVTZ level and allow for spectroscopically accurate predictions of rotational transitions in the ground vibrational state to be made over a broad range of rotational energies (TR < 1000 K). We explored the role that 2-Chloroethanol might play in interstellar molecular clouds by performing calculations on the substitution reaction between HCl and ethylene glycol, and the addition reaction between HCl and oxirane, all of which have been observed in Sagittarius B2(N) and are expected to play important roles in the chemistry that occurs on the icy mantles of interstellar dust grains. While both reactions have relatively high activation barriers, the HCl + oxirane reaction was found be much more exothermic; further calculations on it indicate that a water-like environment significantly reduces the barrier while slightly increasing its exothermicity. These results suggest that 2-Chloroethanol could be efficiently produced from the cosmic ray bombardment of common interstellar ices
Dick B. Janssen - One of the best experts on this subject based on the ideXlab platform.
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Genetic Adaptation of Bacteria to Halogenated Aliphatic Compounds
2013Co-Authors: Dick B. Janssen, Jan R. Van Der Ploeg, Frens PriesAbstract:The bacterial degradation and detoxification of chlorinated xenobiotic compounds requires the production of enzymes that are capable of recognizing and converting compounds which do not occur at significant concentrations in nature. We have studied the catabolic route of 1,2-dichloroethane as an example of a pathway for the conversion of such a synthetic compound. In strains of Xanthobacter and Ancylobacter that have been isolated on 1,2-dichloroethane, the first catabolic step is catalyzed by a hydrolytic haloalkane dehalogenase. The enzyme converts 1,2-dichloroethane to 2-Chloroethanol but is also active with many other environmentally important haloalkanes such as methylchloride, methylbromide, 1,2-dibromoethane, epichlorohydrin, and 1,3-dichloropropene. Further degradation of 2-Chloroethanol proceeds by oxidation to the carboxylic acid and dehalogenation to glycolate. The aldehyde dehydrogenase prevents toxicity of the reactive chloroacetaldehyde that is formed as an intermediate and is necessary for establishing a functional 2-Chloroethanol degradative pathway in a strain that is not capable of growth on this compound.- Environ Health Perspec
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Degradation of 1,2-Dibromoethane by Mycobacterium
1998Co-Authors: Gerrit J. Poelarends, Julian R. Marchesi, Luisa Freitas Dos M. Santos, Dick B. JanssenAbstract:The newly isolated bacterial strain GP1 can utilize 1,2-dibromoethane as the sole carbon and energy source. On the basis of 16S rRNA gene sequence analysis, the organism was identified as a member of the subgroup which contains the fast-growing mycobacteria. The first step in 1,2-dibromoethane metabolism is catalyzed by a hydrolytic haloalkane dehalogenase. The resulting 2-bromoethanol is rapidly converted to ethylene oxide by a haloalcohol dehalogenase, in this way preventing the accumulation of 2-bromoethanol and 2-bromoacetal-dehyde as toxic intermediates. Ethylene oxide can serve as a growth substrate for strain GP1, but the pathway(s) by which it is further metabolized is still unclear. Strain GP1 can also utilize 1-chloropropane, 1-bromopropane, 2-bromoethanol, and 2-Chloroethanol as growth substrates. 2-Chloroethanol and 2-bromo-ethanol are metabolized via ethylene oxide, which for both haloalcohols is a novel way to remove the halide without going through the corresponding acetaldehyde intermediate. The haloalkane dehalogenase gene was cloned and sequenced. The dehalogenase (DhaAf) encoded by this gene is identical to the haloalkane dehalo-genase (DhaA) of Rhodococcus rhodochrous NCIMB 13064, except for three amino acid substitutions and a 14-amino-acid extension at the C terminus. Alignments of the complete dehalogenase gene region of strain GP1 with DNA sequences in different databases showed that a large part of a dhaA gene region, which is also present in R. rhodochrous NCIMB 13064, was fused to a fragment of a haloalcohol dehalogenase gene that was identica
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Identification of chloroacetaldehyde dehydrogenase involved in 1,2-dichloroethane degradation.
Applied and Environmental Microbiology, 1994Co-Authors: Jan Van Der Ploeg, Marten P. Smidt, Andrew S. Landa, Dick B. JanssenAbstract:The degradation of 1,2-dichloroethane and 2-Chloroethanol by Xanthobacter autotrophicus GJ10 proceeds via chloroacetaldehyde, a reactive and potentially toxic intermediate. The organism produced at least three different aldehyde dehydrogenases, of which one is plasmid encoded. Two mutants of strain GJ10, designated GJ10M30 and GJ10M41 could no longer grow an 2-Chloroethanol and were found to lack the NAD-dependent aldehyde dehydrogenase that is the predominant protein in wild-type cells growing on 2-Chloroethanol. Mutant GJ10M30, selected on the basis of its resistance to 1,2-dibromoethane, also had lost haloalkane dehalogenase activity and Hg2+ resistance, indicating plasmid loss. From a gene bank of strain GJ10, different clones that complemented one of these mutants were isolated. In both transconjugants, the aldehyde dehydrogenase that was absent in the mutants was overexpressed. The enzyme was purified and was a tetrameric protein of 55-kDa subunits. The substrate range was rather broad, with the highest activity measured for acetaldehyde. The K-m value for chloroacetaldehyde was 160 mu M, higher than those for other aldehydes tested. It is concluded that the ability of GJ10 to grow with 2-Chloroethanol is due to the high expression level of an aldehyde dehydrogenase with a rather low activity for chloroacetaldehyde.
J.a. Dijk - One of the best experts on this subject based on the ideXlab platform.
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Degradation pathway of 2-Chloroethanol in Pseudomonas stutzeri strain JJ under denitrifying conditions
Archives of Microbiology, 2004Co-Authors: J.a. Dijk, Jan Gerritse, Gosse Schraa, Alfons J M StamsAbstract:The pathway of 2-Chloroethanol degradation in the denitrifying Pseudomonas stutzeri strain JJ was investigated. In cell-free extracts, activities of a phenazine methosulfate (PMS)-dependent Chloroethanol dehydrogenase, an NAD-dependent chloroacetaldehyde dehydrogenase, and a chloroacetate dehalogenase were detected. This suggested that the 2-Chloroethanol degradation pathway in this denitrifying strain is the same as found in aerobic bacteria that degrade Chloroethanol. Activity towards primary alcohols, secondary alcohols, diols, and other chlorinated alcohols could be measured in cell-free extracts with Chloroethanol dehydrogenase (CE-DH) activity. PMS and phenazine ethosulfate (PES) were used as primary electron acceptors, but not NAD, NADP or ferricyanide. Cells of strain JJ cultured in a continuous culture under nitrate limitation exhibited Chloroethanol dehydrogenase activity that was a 12 times higher than in cells grown in batch culture. However, under Chloroethanol-limiting conditions, CE-DH activity was in the same range as in batch culture. Cells grown on ethanol did not exhibit CE-DH activity. Instead, NAD-dependent ethanol dehydrogenase (E-DH) activity and PMS-dependent E-DH activity were detected.
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anaerobic oxidation of 2 Chloroethanol under denitrifying conditions by pseudomonas stutzeri strain jj
Applied Microbiology and Biotechnology, 2003Co-Authors: J.a. Dijk, Gosse Schraa, Alfons J M Stams, Hendrik Ballerstedt, J A M De Bont, Jan GerritseAbstract:A bacterium that uses 2-Chloroethanol as sole energy and carbon source coupled to denitrification was isolated from 1,2-dichloroethane-contaminated soil. Its 16 S rDNA sequence showed 98% similarity with the type strain of Pseudomonas stutzeri (DSM 5190) and the isolate was tentatively identified as Pseudomonas stutzeri strain JJ. Strain JJ oxidized 2-Chloroethanol completely to CO(2) with NO(3)(- )or O(2) as electron acceptor, with a preference for O(2) if supplied in combination. Optimum growth on 2-Chloroethanol with nitrate occurred at 30 degrees C with a mu(max) of 0.14 h(-1) and a yield of 4.4 g protein per mol 2-Chloroethanol metabolized. Under aerobic conditions, the mu(max) was 0.31 h(-1). NO(2)(-) also served as electron acceptor, but reduction of Fe(OH)(3), MnO(2), SO(4)(2-), fumarate or ClO(3)(-) was not observed. Another chlorinated compound used as sole energy and carbon source under aerobic and denitrifying conditions was chloroacetate. Various different bacterial strains, including some closely related Pseudomonas stutzeri strains, were tested for their ability to grow on 2-Chloroethanol as sole energy and carbon source under aerobic and denitrifying conditions, respectively. Only three strains, Pseudomonas stutzeri strain LMD 76.42, Pseudomonas putida US2 and Xanthobacter autotrophicus GJ10, grew aerobically on 2-Chloroethanol. This is the first report of oxidation of 2-Chloroethanol under denitrifying conditions by a pure bacterial culture.