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Woiski C, Dobslaw D, Engesser KH. Isolation and characterization of 2-butoxyethanol degrading bacterial strains. Biodegradation 2020; 31:153-169. [PMID: 32356147 PMCID: PMC7299911 DOI: 10.1007/s10532-020-09900-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 04/10/2020] [Indexed: 10/26/2022]
Abstract
A total of 11 bacterial strains capable of completely degrading 2-butoxyethanol (2-BE) were isolated from forest soil, a biotrickling filter, a bioscrubber, and activated sludge, and identified by 16S rRNA gene sequence analysis. Eight of these strains belong to the genus Pseudomonas; the remaining three strains are Hydrogenophaga pseudoflava BOE3, Gordonia terrae BOE5, and Cupriavidus oxalaticus BOE300. In addition to 2-BE, all isolated strains were able to grow on 2-ethoxyethanol and 2-propoxyethanol, ethanol, n-hexanol, ethyl acetate, 2-butoxyacetic acid (2-BAA), glyoxylic acid, and n-butanol. Apart from the only gram-positive strain isolated, BOE5, none of the strains were able to grow on the nonpolar ethers diethyl ether, di-n-butyl ether, n-butyl vinyl ether, and dibenzyl ether, as well as on 1-butoxy-2-propanol. Strains H. pseudoflava BOE3 and two of the isolated pseudomonads, Pseudomonas putida BOE100 and P. vancouverensis BOE200, were studied in more detail. The maximum growth rates of strains BOE3, BOE100, and BOE200 at 30 °C were 0.204 h-1 at 4 mM, 0.645 h-1 at 5 mM, and 0.395 h-1 at 6 mM 2-BE, respectively. 2-BAA, n-butanol, and butanoic acid were detected as potential metabolites during the degradation of 2-BE. These findings indicate that the degradation of 2-BE by the isolated gram-negative strains proceeds via oxidation to 2-BAA with subsequent cleavage of the ether bond yielding glyoxylate and n-butanol. Since Gordonia terrae BOE5 was the only strain able to degrade nonpolar ethers like diethyl ether, the degradation pathway of 2-BE may be different for this strain.
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Affiliation(s)
- Christine Woiski
- Department of Biological Waste Air Purification, Institute for Sanitary Engineering, Water Quality and Solid Waste Management, University of Stuttgart, Bandtaele 2, 70569, Stuttgart, Germany.
| | - Daniel Dobslaw
- Department of Biological Waste Air Purification, Institute for Sanitary Engineering, Water Quality and Solid Waste Management, University of Stuttgart, Bandtaele 2, 70569, Stuttgart, Germany
| | - Karl-Heinrich Engesser
- Department of Biological Waste Air Purification, Institute for Sanitary Engineering, Water Quality and Solid Waste Management, University of Stuttgart, Bandtaele 2, 70569, Stuttgart, Germany
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2
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Keum YS, Lee YJ, Kim JH. Metabolism of nitrodiphenyl ether herbicides by dioxin-degrading bacterium Sphingomonas wittichii RW1. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2008; 56:9146-9151. [PMID: 18778066 DOI: 10.1021/jf801362k] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Nitrodiphenyl ether herbicides, including chlomethoxyfen, nitrofen, and oxyfluorfen are potent herbicides. Some metabolites and parent compounds are considered as possible mutagens and endocrine disruptors. Both properties pose serious hygienic and environmental risks. Sphingomonas wittichii RW1 is a well-known degrader of polychlorinated dibenzo- p-dioxins, dibenzofurans, and diphenyl ethers. However, no detailed research of its metabolic activity has been performed against pesticides with a diphenyl ether scaffold. In this study, we report S. wittichii RW1 as a very potent diphenyl ether herbicide-metabolizing bacterium with broad substrate specificity. The structures of metabolites were determined by instrumental analysis and synthetic standards. Most pesticides were rapidly removed from the culture medium in the order of nitrofen > oxyfluorfen > chlomethoxyfen. In general, herbicides were degraded through the initial reduction and N-acetylation of nitro groups, followed by ether bond cleavage. Relatively low concentrations of phenolic and catecholic metabolites throughout the study suggested that these metabolites were rapidly metabolized and incorporated into primary metabolism. These results indicate that strain RW1 has very versatile metabolic activities over a wide range of environmental contaminants.
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Affiliation(s)
- Young Soo Keum
- Department of Agricultural Biotechnology, Seoul National University, Seoul 151-742, Korea
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3
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Two angular dioxygenases contribute to the metabolic versatility of dibenzofuran-degrading Rhodococcus sp. strain HA01. Appl Environ Microbiol 2008; 74:3812-22. [PMID: 18441103 DOI: 10.1128/aem.00226-08] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Rhodococcus sp. strain HA01, isolated through its ability to utilize dibenzofuran (DBF) as the sole carbon and energy source, was also capable, albeit with low activity, of transforming dibenzo-p-dioxin (DD). This strain could also transform 3-chlorodibenzofuran (3CDBF), mainly by angular oxygenation at the ether bond-carrying carbon (the angular position) and an adjacent carbon atom, to 4-chlorosalicylate as the end product. Similarly, 2-chlorodibenzofuran (2CDBF) was transformed to 5-chlorosalicylate. However, lateral oxygenation at the 3,4-positions was also observed and yielded the novel product 2-chloro-3,4-dihydro-3,4-dihydroxydibenzofuran. Two gene clusters encoding enzymes for angular oxygenation (dfdA1A2A3A4 and dbfA1A2) were isolated, and expression of both was observed during growth on DBF. Heterologous expression revealed that both oxygenase systems catalyze angular oxygenation of DBF and DD but exhibited complementary substrate specificity with respect to CDBF transformation. While DfdA1A2A3A4 oxygenase, with high similarity to DfdA1A2A3A4 oxygenase from Terrabacter sp. strain YK3, transforms 3CDBF by angular dioxygenation at a rate of 29% +/- 4% that of DBF, 2CDBF was not transformed. In contrast, DbfA1A2 oxygenase, with high similarity to the DbfA1A2 oxygenase from Terrabacter sp. strain DBF63, exhibited complementary activity with angular oxygenase activity against 2CDBF but negligible activity against 3CDBF. Thus, Rhodococcus sp. strain HA01 constitutes the first described example of a bacterial strain where coexpression of two angular dioxygenases was observed. Such complementary activity allows for the efficient transformation of chlorinated DBFs.
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Halden RU, Peters EG, Halden BG, Dwyer DF. Transformation of mono- and dichlorinated phenoxybenzoates by phenoxybenzoate-dioxygenase inPseudomonas pseudoalcaligenes POB310 and a modified diarylether-metabolizing bacterium. Biotechnol Bioeng 2000. [DOI: 10.1002/(sici)1097-0290(20000705)69:1<107::aid-bit13>3.0.co;2-t] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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5
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Halden RU, Tepp SM, Halden BG, Dwyer DF. Degradation of 3-phenoxybenzoic acid in soil by Pseudomonas pseudoalcaligenes POB310(pPOB) and two modified Pseudomonas strains. Appl Environ Microbiol 1999; 65:3354-9. [PMID: 10427019 PMCID: PMC91504 DOI: 10.1128/aem.65.8.3354-3359.1999] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/1999] [Accepted: 05/11/1999] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas pseudoalcaligenes POB310(pPOB) and Pseudomonas sp. strains B13-D5(pD30.9) and B13-ST1(pPOB) were introduced into soil microcosms containing 3-phenoxybenzoic acid (3-POB) in order to evaluate and compare bacterial survival, degradation of 3-POB, and transfer of plasmids to a recipient bacterium. Strain POB310 was isolated for its ability to use 3-POB as a growth substrate; degradation is initiated by POB-dioxygenase, an enzyme encoded on pPOB. Strain B13-D5 contains pD30.9, a cloning vector harboring the genes encoding POB-dioxygenase; strain B13-ST1 contains pPOB. Degradation of 3-POB in soil by strain POB310 was incomplete, and bacterial densities decreased even under the most favorable conditions (100 ppm of 3-POB, supplementation with P and N, and soil water-holding capacity of 90%). Strains B13-D5 and B13-ST1 degraded 3-POB (10 to 100 ppm) to concentrations of <50 ppb with concomitant increases in density from 10(6) to 10(8) CFU/g (dry weight) of soil. Thus, in contrast to strain POB310, the modified strains had the following two features that are important for in situ bioremediation: survival in soil and growth concurrent with removal of an environmental contaminant. Strains B13-D5 and B13-ST1 also completely degraded 3-POB when the inoculum was only 30 CFU/g (dry weight) of soil. This suggests that in situ bioremediation may be effected, in some cases, with low densities of introduced bacteria. In pure culture, transfer of pPOB from strains POB310 and B13-ST1 to Pseudomonas sp. strain B13 occurred at frequencies of 5 x 10(-7) and 10(-1) transconjugant per donor, respectively. Transfer of pPOB from strain B13-ST1 to strain B13 was observed in autoclaved soil but not in nonautoclaved soil; formation of transconjugant bacteria was more rapid in soil containing clay and organic matter than in sandy soil. Transfer of pPOB from strain POB310 to strain B13 in soil was never observed.
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Affiliation(s)
- R U Halden
- Department of Civil Engineering, University of Minnesota, Minneapolis, Minnesota 55455, USA
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6
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Halden RU, Halden BG, Dwyer DF. Removal of dibenzofuran, dibenzo-p-dioxin, and 2-chlorodibenzo-p-dioxin from soils inoculated with Sphingomonas sp. strain RW1. Appl Environ Microbiol 1999; 65:2246-9. [PMID: 10224029 PMCID: PMC91326 DOI: 10.1128/aem.65.5.2246-2249.1999] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/1999] [Accepted: 02/23/1999] [Indexed: 11/20/2022] Open
Abstract
Removal of dibenzofuran, dibenzo-p-dioxin, and 2-chlorodibenzo-p-dioxin (2-CDD) (10 ppm each) from soil microcosms to final concentrations in the parts-per-billion range was affected by the addition of Sphingomonas sp. strain RW1. Rates and extents of removal were influenced by the density of RW1 organisms. For 2-CDD, the rate of removal was dependent on the content of soil organic matter (SOM), with half-life values ranging from 5.8 h (0% SOM) to 26.3 h (5.5% SOM).
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Affiliation(s)
- R U Halden
- Department of Civil Engineering, University of Minnesota, Minneapolis, Minnesota 55455, USA
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7
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Eaton RW, Selifonov SA. Biotransformation of 6,6-Dimethylfulvene by Pseudomonas putida RE213. Appl Environ Microbiol 1996; 62:756-60. [PMID: 16535266 PMCID: PMC1388791 DOI: 10.1128/aem.62.3.756-760.1996] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The biotransformation of 6,6-dimethylfulvene [5-(1-methylethylidene)-1,3-cyclopentadiene], a nonaromatic C(inf5) carbocyclic analog of isopropylbenzene, was examined by using Pseudomonas putida RE213, a Tn5-generated dihydrodiol-accumulating mutant of the isopropylbenzene-degrading strain P. putida RE204. 6,6-Dimethylfulvene was converted to a single chiral product identified as (+)-(1R,2S)-cis-1,2-dihydroxy-5-(1-methylethylidene)-3-cyclopentene. This isopropylbenzene 2,3-dioxygenase-catalyzed transformation demonstrates the potential of bacterial arene dioxygenases for the direct conversion of cyclopentadienylidene compounds to homochiral C(inf5) carbocyclic cis-diols for use in enantiocontrolled organic syntheses.
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8
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Harms H, Wilkes H, Wittich R, Fortnagel P. Metabolism of Hydroxydibenzofurans, Methoxydibenzofurans, Acetoxydibenzofurans, and Nitrodibenzofurans by Sphingomonas sp. Strain HH69. Appl Environ Microbiol 1995; 61:2499-505. [PMID: 16535067 PMCID: PMC1388485 DOI: 10.1128/aem.61.7.2499-2505.1995] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The metabolism of 11 substituted dibenzofurans by the dibenzofuran-degrading Sphingomonas sp. strain HH69 was investigated. Strain HH69 utilizes 2-, 3-, and 4-acetoxydibenzofuran as well as 2-, 3-, and 4-hydroxydibenzofuran as sole sources of carbon and energy. The degradation of acetoxydibenzofurans is initiated by hydrolysis of the ester bonds, yielding the corresponding hydroxydibenzofurans and acetate. Strain HH69 grew on 2-methoxydibenzofuran only after it was adapted to the utilization of 5-methoxysalicylic acid, whereas 3- and 4-methoxydibenzofuran as well as 2- and 3-nitrodibenzofuran were only cooxidized. During the breakdown of all eight hydroxy-, methoxy-, and nitrodibenzofurans studied here, the corresponding substituted salicylic acids accumulated in the culture broth. In the cases of 2- and 3-hydroxydibenzofuran as well as 2- and 3-nitrodibenzofuran, salicylic acid was also formed. Those four dibenzofurans which did not serve as carbon sources for strain HH69 were converted to a nonutilizable salicylic acid derivative. From turnover experiments with the mutant HH69/II, which is deficient in meta-cleavage, 2,2(prm1),3,4(prm1)-tetrahydroxybiphenyl, 2,2(prm1),3-trihydroxy-5(prm1)-methoxybiphenyl, 2,2(prm1),3-trihydroxy-5(prm1)-nitrobiphenyl, and 2,2(prm1),3-trihydroxy-4(prm1)-nitrobiphenyl were isolated as the main products formed from 3-hydroxydibenzofuran, 2-methoxydibenzofuran, and 2- and 3-nitrodibenzofuran, respectively. These results indicate significant regioselectivity for the dioxygenolytic cleavage of the ether bond of these monosubstituted dibenzofurans, with a preference for the nonsubstituted aromatic nucleus. Substituted trihydroxybiphenyls are converted further by meta-cleavage followed by the removal of the side chain of the resulting product. A stepwise degradation of this side chain was found to be involved in the metabolism of 2-hydroxydibenzofuran.
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9
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Dehmel U, Engesser KH, Timmis KN, Dwyer DF. Cloning, nucleotide sequence, and expression of the gene encoding a novel dioxygenase involved in metabolism of carboxydiphenyl ethers in Pseudomonas pseudoalcaligenes POB310. Arch Microbiol 1995; 163:35-41. [PMID: 7710319 DOI: 10.1007/bf00262201] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Pseudomonas pseudoalcaligenes strain POB310 degrades 3- and 4-carboxydiphenyl ether. The initial reaction involves an angular dioxygenation yielding an unstable hemiacetal that spontaneously decays to phenol and protocatechuate. We cloned a DNA fragment containing the gene encoding the initial dioxygenase from an unstable, self-transmissible plasmid. Sequence analysis revealed two open reading frames encoding proteins with putative molecular masses of 46.3 and 33.6 kDa. The deduced amino acid sequences showed homologies to oxygenase and reductase subunits of aromatic ring-activating dioxygenases, and contained regions identical to consensus sequences that bind chloroplast-like and Rieske-type [2Fe2S] clusters, suggesting that the initial dioxygenase is a class IA aromatic ring-activating dioxygenase system. Initial dioxygenase activity was induced in bacteria grown in M9 minimal medium containing 3- or 4-carboxydiphenyl ether or phenol as carbon source, indicating that the regulation is dependent on the phenol pathway. The maximal specific activity was measured at the beginning of the exponential growth phase.
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Affiliation(s)
- U Dehmel
- Department of Microbiology, G.B.F. National Research Center for Biotechnology, Braunschweig, Germany
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10
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Trenz SP, Engesser KH, Fischer P, Knackmuss HJ. Degradation of fluorene by Brevibacterium sp. strain DPO 1361: a novel C-C bond cleavage mechanism via 1,10-dihydro-1,10-dihydroxyfluoren-9-one. J Bacteriol 1994; 176:789-95. [PMID: 8300532 PMCID: PMC205116 DOI: 10.1128/jb.176.3.789-795.1994] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Angular dioxygenation has been established as the crucial step in dibenzofuran degradation by Brevibacterium sp. strain DPO 1361 (V. Strubel, K. H. Engesser, P. Fischer, and H.-J. Knackmuss, J. Bacteriol. 173:1932-1937, 1991). The same strain utilizes biphenyl and fluorene as sole sources of carbon and energy. The fluorene degradation sequence is proposed to be initiated by oxidation of the fluorene methylene group to 9-fluorenol. Cells grown on fluorene exhibit pronounced 9-fluorenol dehydrogenase activity. Angular dioxygenation of the 9-fluorenone thus formed yields 1,10-dihydro-1,10-dihydroxyfluoren-9-one (DDF). A mechanistic model is presented for the subsequent C-C bond cleavage by an NAD(+)-dependent DDF dehydrogenase, acting on the angular dihydrodiol. This enzyme was purified and characterized as a tetramer of four identical 40-kDa subunits. The following Km values were determined: 13 microM for DDF and 65 microM for 2,3-dihydro-2,3-dihydroxybiphenyl. The enzyme also catalyzes the production of 3-(2'-carboxyphenyl)catechol, which was isolated, and structurally characterized, in the form of the corresponding lactone, 4-hydroxydibenzo-(b,d)-pyran-6-one. Stoichiometry analysis unequivocally demonstrates that angular dioxygenation constitutes the principal pathway in Brevibacterium sp. strain DPO 1361.
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Affiliation(s)
- S P Trenz
- Institut für Mikrobiologie, Stuttgart, Germany
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11
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Pfeifer F, Trüper HG, Klein J, Schacht S. Degradation of diphenylether by Pseudomonas cepacia Et4: enzymatic release of phenol from 2,3-dihydroxydiphenylether. Arch Microbiol 1993; 159:323-9. [PMID: 7683455 DOI: 10.1007/bf00290914] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
2,3-Dihydroxybiphenyl dioxygenase from Pseudomonas cepacia Et 4 was found to catalyze the ring fission of 2,3-dihydroxydiphenylether in the course of diphenylether degradation. The enzyme was purified and characterized. It had a molecular mass of 240 kDa and is dissociated by SDS into eight subunits of equal mass (31 kDa). The purified enzyme was found to be most active with 2,3-dihydroxybiphenyl as substrate and showed moderate activity with 2,3-dihydroxydiphenylether, catechol and some 3-substituted catechols. The Km-value of 1 microM for 2,3-dihydroxydiphenylether indicated a high affinity of the enzyme towards this substrate. The cleavage of 2,3-dihydroxydiphenylether by 2,3-dihydroxybiphenyl dioxygenase lead to the formation of phenol and 2-pyrone-6-carboxylate as products of ring fission and ether cleavage without participation of free intermediates. Isotope labeling experiments carried out with 18O2 and H2(18)O indicated the incorporation of 18O from the atmosphere into the carboxyl residue as well as into the carbonyl oxygen of the lactone moiety of 2-pyrone-6-carboxylate. Based on these experimental findings the reaction mechanism for the formation of phenol and 2-pyrone-6-carboxylate is proposed in accordance with the mechanism suggested by Kersten et al. (1982).
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Affiliation(s)
- F Pfeifer
- DMT-Gesellschaft für Forschung und Prüfung mbH, Institut für chemische Umwelttechnologie, Essen, Germany
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12
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Biodegradation of diphenyl ether and its monohalogenated derivatives by Sphingomonas sp. strain SS3. Appl Environ Microbiol 1992; 58:2744-50. [PMID: 1444384 PMCID: PMC183002 DOI: 10.1128/aem.58.9.2744-2750.1992] [Citation(s) in RCA: 113] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The bacterium Sphingomonas sp. strain SS3, which utilizes diphenyl ether and its 4-fluoro, 4-chloro, and (to a considerably lesser extent) 4-bromo derivatives as sole sources of carbon and energy, was enriched from soil samples of an industrial waste deposit. The bacterium showed cometabolic activities toward all other isomeric monohalogenated diphenyl ethers. During diphenyl ether degradation in batch culture experiments, phenol and catechol were produced as intermediates which were then channeled into the 3-oxoadipate pathway. The initial step in the degradation follows the recently discovered mechanism of 1,2-dioxygenation, which yields unstable phenolic hemiacetals from diphenyl ether structures. Oxidation of the structure-related dibenzo-p-dioxin yielded 2-(2-hydroxyphenoxy)-muconate upon ortho cleavage of the intermediate 2,2',3-trihydroxydiphenyl ether. Formation of phenol, catechol, halophenol, and halocatechol from the conversion of monohalogenated diphenyl ethers gives evidence for a nonspecific attack of the dioxygenating enzyme system.
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14
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Higson FK. Microbial degradation of biphenyl and its derivatives. ADVANCES IN APPLIED MICROBIOLOGY 1992; 37:135-64. [PMID: 1642156 DOI: 10.1016/s0065-2164(08)70254-5] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- F K Higson
- Department of Soil and Environmental Sciences, University of California, Riverside 92521
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15
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Topp E, Akhtar MH. Identification and Characterization of a
Pseudomonas
Strain Capable of Metabolizing Phenoxybenzoates. Appl Environ Microbiol 1991; 57:1294-300. [PMID: 16348477 PMCID: PMC182945 DOI: 10.1128/aem.57.5.1294-1300.1991] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
3-Phenoxybenzoate is a transient metabolite from the breakdown of a number of pyrethroid insecticides in soil. In this study, we identified and characterized a bacterium which could grow on 3-phenoxybenzoate, converting it to phenol. On the basis of morphological and biochemical features, the 3-phenoxybenzoatedegrading isolate was determined to be a
Pseudomonas
species, probably a strain of
Pseudomonas delafieldii
, now designated
Pseudomonas
strain ET1.
Pseudomonas
strain ET1 grew on 3-phenoxybenzoate with a generation time of 3 h and a specific rate of metabolism of (2.6 ± 0.9) × 10
-13
g of 3-phenoxybenzoate consumed cell
-1
h
-1
. The
K
m
for 3-phenoxybenzoate metabolism was 1.4 ± 0.8 μM. The metabolism of 3-phenoxybenzoate was constitutive and not subject to catabolite repression. The metabolism of a variety of substituted diaryl ether compounds was examined. 3- and 4-Phenoxybenzoates were metabolized, but 2-phenoxybenzoate was not. Phenoxy-substituted benzyl aldehyde was metabolized, but phenoxy-substituted benzyl alcohol, benzene, phenol, and aniline were not. Derivatives of 3-phenoxybenzoate substituted in the 4′ position with hydroxyl, methyl, or chlorine were metabolized, yielding the corresponding 4-substituted phenol. 3-(2-Hydroxyphenoxy)benzoate was not metabolized, but 3-phenoxy-4-fluorobenzoate was. These results indicate that the metabolism of the tested diaryl ether compounds was restricted to 4-phenoxybenzoate, 3-phenoxybenzyl aldehyde, and 3-phenoxybenzoate derivatives without a substitution in the 2′ position.
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Affiliation(s)
- E Topp
- Land Resource Research Centre and Animal Research Centre, Research Branch, Agriculture Canada, Central Experimental Farm, Ottawa, Ontario, Canada K1A 0C6
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16
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