Degradation of O,O-dimethyl phosphorodithioate by activated sludge.

Kanagawa, Takahiro; Dazai, Michio; Takahara, Yoshimasa

doi:10.1271/bbb1961.44.2631

Cited by 3 publications

(3 citation statements)

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“…After 2 h, the supernatant of the degradation assay was applied to both two thin-layer chromatography (TLC) and colorimetric analysis as reported previously (Munnecke and Hsieh 1976;Kanagawa et al 1980). Cell-less DM-D medium was used as the control.…”

Section: Characterization Of the Isolatementioning

confidence: 99%

Co-metabolic degradation of dimethoate by Raoultella sp. X1

et al. 2008

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A bacterium Raoultella sp. X1, based on its 16S rRNA gene sequence, was isolated. Characteristics regarding the bacterial morphology, physiology, and genetics were investigated with an electron microscopy and conventional microbiological techniques. Although the isolate grew and degraded dimethoate poorly when the chemical was used as a sole carbon and energy source, it was able to remove up to 75% of dimethoate via co-metabolism. With a response surface methodology, we optimized carbon, nitrogen and phosphorus concentrations of the media for dimethoate degradation. Raoultella sp. X1 has a potential to be a useful organism for dimethoate degradation and a model strain for studying this biological process at the molecular level.

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Section: Characterization Of the Isolatementioning

confidence: 99%

Co-metabolic degradation of dimethoate by Raoultella sp. X1

et al. 2008

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“…The first two compounds possess a POOOC bond, while formothion and malathion are characterized by a POSOC bond identical to that of dimethoate. Products of the degradation assay were determined by previously reported methods (6). According to colorimetric results and thin-layer chromatography, O,O-dimethyl phosphorothioate exists in the supernatant of the degradation assay mixture but not in that of the control assay mixture.…”

Section: Vol 67 2001mentioning

confidence: 99%

Purification and Characterization of a Dimethoate-Degrading Enzyme of Aspergillus niger ZHY256, Isolated from Sewage

Liu

Chung

Xiong³

2001

Appl Environ Microbiol

101

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A dimethoate-degrading enzyme from Aspergillus niger ZHY256 was purified to homogeneity with a specific activity of 227.6 U/mg of protein. The molecular mass of the purified enzyme was estimated to be 66 kDa by gel filtration and 67 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The isoelectric point was found to be 5.4, and the enzyme activity was optimal at 50°C and pH 7.0. The activity was inhibited by most of the metal ions and reagents, while it was induced by Cu 2؉ . The Michaelis constant (K m ) and V max for dimethoate were 1.25 mM and 292 mol min ؊1 mg of protein ؊1, respectively.Organophosphorus pesticides have been used in large quantities throughout the world since the first introduction of a synthetic insecticide, parathion, for use in crop protection in 1944 (16). Problems of contamination resulting from surplus pesticides and wastewater from pesticide factories have become obvious. The transformation of pesticides in the environment results from physicochemical reactions as well as from the activity of cellular or extracellular components of the biota (microorganisms, plants, and animals), but the principal biological pathway is microbial degradation (7): microorganisms can metabolize various pesticides both in soil and in water. The earlier metabolic studies on pesticides helped to develop a new approach to the detoxification of pesticides using cell-free enzymes from adapted microorganisms to resolve problems related to whole-cell metabolism of pesticides. Munnecke purified an enzyme from a mixed bacterial culture grown on parathion and found that it hydrolyzed parathion and related organophosphorus insecticides (13). Mulbry and Karns purified three unique parathion hydrolases from gram-negative bacterial isolates. These enzymes with different characteristics were exploited in different types of waste disposal (12). Although there have been a number of reports on the metabolism of parathion by enzyme preparations from bacteria or by mixed-culture bacteria (12-14), there have been no successful cell-free studies with fungi capable of degrading organophosphorus insecticides. To our knowledge, this is the first dimethoate-degrading enzyme purified to homogeneity from a fungus. Characterization and comparison of the degrading enzymes from different microorganisms may help us to understand fully how these enzymatic activities may evolve and how organophosphorus insecticides are degraded in the ecosystem.Microorganism and enzyme production. All experiments were performed in triplicate, and results, where appropriate, are presented as means. Aspergillus niger ZHY256 was isolated from sewage and the soil of cotton fields where pesticides were heavily used and maintained on potato dextrose agar. For enzyme production, the fungus was grown on basal salt medium (0.2% NaNO 3 , 0.05% KCl, 0.05% MgSO 4 ⅐ 7H 2 O, 0.02% BaCl 2 , 0.01% MnSO 4 , 0.005% CaCl 2 , pH 6.8, supplemented with dimethoate at a concentration of 0.25% [wt/vol]). Dimethoate-degrading enzyme activity was detected at the la...

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“…The breakdown of the more complex sulphur compound, O, O-dimethylphosphorodithioate (DMDTP), by activated sludge [11] was previously shown to be brought about by the concerted action of two bacteria, Pseudomonas AK-2 and T. thioparus TK-1 [12]. The latter grew at the expense of the sulphide oxidation, producing dimethyl phosphate (DMP) and sulphate, while the Pseudomonas used DMP for growth, releasing orthophosphate.…”

Section: Introductionmentioning

confidence: 99%

Breakdown of dimethyl sulphide by mixed cultures and byThiobacillus thioparus

Kanagawa

Kelly

1986

FEMS Microbiology Letters

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Dimethyl sulphide (DMS) was degraded by acclimatized activated sludge and by a mixed culture of Thiobacillus thioparus TK‐1 and Pseudomonas sp. AK‐2. While both these organisms persisted in stable co‐culture on DMS, it was found that T. thioparus TK‐1 and the derived strain TK‐m grew in pure culture on DMS, and oxidized DMS with an apparent Km of 4.5 × 10−5 M. During growth, all the DMS‐sulphur was oxidized stoichiometrically to sulphate but no methanol was detected in pure cultures of TK‐m. DMS‐carbon was probably converted to CO2, since the fixation of 14CO2 was progressively diluted during growth of a culture on 14CO2 and DMS. Growth yields were consistent with autotrophic growth, dependent on the oxidation of the methyl residues to CO2 (probably with formaldehyde as a first intermediate) and the sulphide to sulphate. The organism thus appears to exhibit a mixture, from the one substrate, of chemolithotrophic and methylotrophic energy generation supporting autotrophic growth with CO2 fixation.

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Degradation of O,O-dimethyl phosphorodithioate by activated sludge.

Cited by 3 publications

References 0 publications

Co-metabolic degradation of dimethoate by Raoultella sp. X1

Co-metabolic degradation of dimethoate by Raoultella sp. X1

Purification and Characterization of a Dimethoate-Degrading Enzyme of Aspergillus niger ZHY256, Isolated from Sewage

Breakdown of dimethyl sulphide by mixed cultures and byThiobacillus thioparus

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