The Experts below are selected from a list of 1248 Experts worldwide ranked by ideXlab platform
H. W. Kirby - One of the best experts on this subject based on the ideXlab platform.
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Effects of Dinitroaniline Herbicides, Carboxin-Pentachloronitrobenzene Seed Treatment, and Rhizoctonia Disease on Soybean
Plant Disease, 1992Co-Authors: E. M. Bauske, H. W. KirbyAbstract:The effect of trifluralin, pendimethalin, and ethalfluralin and disease caused by Rhizoctonia solani on soybean (Glycine max) was determined with field and growth chamber studies. In field studies, oats infested with R. solani placed in furrow at planting significantly reduced plant growth variables. No significant interactions were observed between herbicides and inoculum treatments. Effects of inoculum were significantly reduced with carboxin-Pentachloronitrobenzene seed treatment, in growth chamber studies, steamed and nonsteamed field soil were used (...)
Bartisetiani Muntalif - One of the best experts on this subject based on the ideXlab platform.
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Relationship between the biodegradative capability of soil micromycetes for pentachlorophenol and for Pentachloronitrobenzene.
The Science of the total environment, 1992Co-Authors: F. Seigle-murandi, Jean-louis Benoit-guyod, R. Steiman, Bartisetiani Muntalif, Lucile SageAbstract:A collection of 1056 strains in our laboratory were incubated with various xenobiotics among which were two potent fungicides: pentachlorophenol (PCP) and Pentachloronitrobenzene (PCNB). The production of extracellular phenoloxidases were examined, using a series of ten different reagents. On the whole, PCNB is less accessible to fungal degradation than PCP. Although no correlation was found between the biodegradative capability of individual fungal strains for PCP or for PCNB, when taxonomic groups were considered as a whole, the same activity profiles were found. Zygomycetes were the most efficient; yeasts the least efficient towards both substrates. A more detailed study of the metabolism of both substrates on selected strains is in progress.
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Degradation of Pentachloronitrobenzene by micromycetes isolated from soil
Science of The Total Environment, 1992Co-Authors: R. Steiman, Jean-louis Benoit-guyod, F. Seigle-murandi, Bartisetiani MuntalifAbstract:Abstract A wide study has been conducted on the fate of xenobiotics in the environment and more particularly on the biodegradation of these compounds. The selection of fungal strains able to degrade Pentachloronitrobenzene (PCNB) has been performed. Of the collection of strains in our laboratory 1060 were incubated with PCNB (100 mg/l) for 5 days in liquid synthetic medium. The production of extracellular phenoloxidases was examined by using ten different reagents. We found that only 3% of the strains were able to degrade PCNB by over 70%. The most performant groups were Mucedinaceeae and Zygomycetes. No correlation was found between the production of extracellular phenoloxidases and the biodegradative capability of individual strains. A detailed study of PCNB metabolism by selected strains is in progress.
Spyros G. Pavlostathis - One of the best experts on this subject based on the ideXlab platform.
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Occurrence, Toxicity, and Biotransformation of Pentachloronitrobenzene and Chloroanilines
Critical Reviews in Environmental Science and Technology, 2014Co-Authors: Didem Okutman Tas, Spyros G. PavlostathisAbstract:Chloronitrobenzenes and chloroanilines are among the recalcitrant, toxic environmental contaminants that pose chronic threat to the health and safety of humans and wildlife. Pentachloronitrobenzene (PCNB) is an emerging environmental chloronitroaromatic contaminant, widely distributed in the environment due to its worldwide intensive use. The interactions between potentially competing microbial processes (i.e., iron reduction, nitrate reduction, methanogenesis, and dechlorination) can significantly influence the environmental fate of PCNB and chloroanilines resulting from the reductive biotransformation of PCNB. This review evaluates presently available toxicity and distribution information as well as the transformation and degradation potential of PCNB and chloroanilines under different environmental conditions.
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Microbial transformation of Pentachloronitrobenzene under nitrate reducing conditions
Biodegradation, 2010Co-Authors: Didem Okutman Tas, Spyros G. PavlostathisAbstract:The effect of Pentachloronitrobenzene (PCNB) on denitrification was assessed with two denitrifying cultures (PCNB-free control and PCNB-acclimated) developed from a contaminated estuarine sediment. PCNB was transformed to pentachloroaniline (PCA) in the PCNB-acclimated culture repeatedly amended with 0.1 μM PCNB, but further dechlorination or degradation of PCA was not observed for almost 1 year. The effect of PCNB on denitrification was also investigated with the PCNB-free control culture. PCNB at an initial concentration of 13 μM was transformed to PCA simultaneously with nitrate reduction but only after the nitrate concentration was at or below 20 mg N/l. PCNB addition at an initial concentration of 13 μM to the control denitrifying culture developed as PCNB-free culture resulted in a transient accumulation of nitric oxide (NO) and nitrous oxide (N_2O). Similarly to the PCNB-acclimated culture, PCNB transformation to PCA started when the nitrate concentration decreased to about 20 mg N/l. A low degree of nitro group removal resulting in the formation of pentachlorobenzene (PeCB) was also observed in the control culture when amended with 13 μM PCNB. Further transformation or degradation of PCA was not observed in all cultures maintained under active nitrate reducing conditions. Based on the results of this study, the presence of nitrate at low concentrations in anoxic/anaerobic soil and sediments is not expected to negatively affect the biotransformation of PCNB to PCA, but dechlorination or degradation of PCA is not expected under active nitrate reducing conditions.
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Temperature and pH effect on the microbial reductive transformation of Pentachloronitrobenzene.
Journal of Agricultural and Food Chemistry, 2007Co-Authors: Didem Okutman Tas, Spyros G. PavlostathisAbstract:The effect of pH and temperature on the microbial reductive transformation of Pentachloronitrobenzene (PCNB), an organochlorine fungicide, was investigated with a mixed fermentative/methanogenic culture developed from a contaminated estuarine sediment. Culture series were incubated at a temperature range from 4 to 45 °C at pH 6.9 ± 0.1 and at a pH range from 2.7 ± 0.1 to 7.6 ± 0.1 at 22 °C. Significant differences were observed in terms of biotransformation rate, extent, and products as a function of temperature. Incubation at different pH values resulted in differences in biotransformation rate and extent, but not in terms of products formed. PCNB (3 μM) was transformed to pentachloroaniline (PCA) in all culture series. However, sequential dechlorination of PCA was observed only at a temperature range from 4 to 35 °C and at a pH range from 6.2 ± 0.1 to 7.6 ± 0.1. The highest PCA dechlorination rate was observed at 22 °C and at pH 7.6 ± 0.1. The effect of temperature on the PCA dechlorination rate was mod...
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Microbial Reductive Transformation of Pentachloronitrobenzene under Methanogenic Conditions
Environmental science & technology, 2005Co-Authors: Didem Okutman Tas, Spyros G. PavlostathisAbstract:The reductive transformation of Pentachloronitrobenzene (PCNB), an organochlorine fungicide, was investigated with a mixed, methanogenic culture developed from a contaminated estuarine sediment. Batch assays performed with this enrichment culture resulted in the biotransformation of PCNB to pentachloroaniline (PCA), which was then sequentially dechlorinated as follows: PCA → 2,3,4,5- and 2,3,5,6-tetrachloroaniline (TeCA) → 2,4,5- and 2,3,5-trichloroaniline (TrCA) → 2,4-, 2,5-, and 3,5-dichloroaniline (DCA) → 3- and 4-chloroaniline (CA) (low levels). Glucose fermentation, methanogenesis, and dechlorination were not inhibited at an initial PCNB concentration up to 40 μM, which is 27 times higher than its aqueous solubility. The addition of 25 mM 2-bromoethanesulfonate (BES) to the PCNB-amended culture resulted in the complete inhibition of methanogenesis, but the biotransformation of PCNB to PCA and its sequential dechlorination pathway were not affected. The addition of sodium azide (200 mg/L) to the PCNB...
Jean-louis Benoit-guyod - One of the best experts on this subject based on the ideXlab platform.
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Biotransformation and biosorption of Pentachloronitrobenzene by fungal mycelia
Mycological Research, 1996Co-Authors: Didier Lièvremont, Françoise Seigle-murandi, Jean-louis Benoit-guyod, Régine SteimanAbstract:The ability of Sporothrix cyanescens, Mucor racemosus and Rhizopus arrhizus to transform high concentrations of Pentachloronitrobenzene, PCNB (100 mg l −1 ) in culture media was monitored by hplc analysis of the culture media over 20 d. The cultures of S. cyanescens and M. racemosus demonstrated high PCNB-transforming ability (78–81%), whereas removal of PCNB by R. arrhizus was less efficient. The removal of PCNB by each fungus was best illustrated when expressed as the ratio of the mass of chemical to the mass of mycelium, instead of medium concentration. Fungi removed > 50% of the PCNB within 48 h, and transformation products were revealed after 24 h. In addition, adsorption on fresh mycelia, as well as on lyophilized and oven-dried mycelia, of the three stains was measured. Fresh mycelium of M. racemosus had a mean adsorption value of 20·8 μg of PCNB mg −1 dry biomass during a 20 d period. For S. cyanescens and R. arrhizus low values were observed (0·5–2·5 μg mg −1 ). Adsorption values were dependent on species, physiological state, media and time. Removal of PCNB by S. cyanescens and M. racemosus was more efficiently controlled with living biomass and by biotransformation process, than by adsorption.
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Effects of culture parameters on Pentachloronitrobenzene removal by Sporothrix cyanescens
Chemosphere, 1996Co-Authors: Didier Lièvremont, Françoise Seigle-murandia, Jean-louis Benoit-guyodAbstract:Abstract The ability of S. cyanescens to degrade high concentration of Pentachloronitrobenzene (PCNB 100mg/l or 0.34niM) was focused on ways to increase or optimize rates of biodegradation. Experiments were conducted to eyimine the effects of several culture parameters on PCNB revoval. The levels of PCNB in the medium were monitored by HPLC analysis over 5 days. Carbon, nitrogen were shown to strongly influence the extent of its removal. In these experiments, PCNB degradation best results were obtained under low concentrations in these elements corresponding, in term of chemical dose expressed as the ratio of the quantity of chemical to the mass of mycelium inoculated, of a maximum value of 24.5μg/mg. Moreover, S. cyanescens proved to perform a rather efficient degradation (18.9μg/mg) when a complex carbohydrate, starch, was given as the major carbon source. In parallel, the sensitivity of S. cyanescens to PCNB has been determined by measuring growth inhibition on PCNB supplemented solid media. In the range of chemical doses tested (0–150mg/1), no lethal effects were observed.
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Relationship between the biodegradative capability of soil micromycetes for pentachlorophenol and for Pentachloronitrobenzene.
The Science of the total environment, 1992Co-Authors: F. Seigle-murandi, Jean-louis Benoit-guyod, R. Steiman, Bartisetiani Muntalif, Lucile SageAbstract:A collection of 1056 strains in our laboratory were incubated with various xenobiotics among which were two potent fungicides: pentachlorophenol (PCP) and Pentachloronitrobenzene (PCNB). The production of extracellular phenoloxidases were examined, using a series of ten different reagents. On the whole, PCNB is less accessible to fungal degradation than PCP. Although no correlation was found between the biodegradative capability of individual fungal strains for PCP or for PCNB, when taxonomic groups were considered as a whole, the same activity profiles were found. Zygomycetes were the most efficient; yeasts the least efficient towards both substrates. A more detailed study of the metabolism of both substrates on selected strains is in progress.
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Degradation of Pentachloronitrobenzene by micromycetes isolated from soil
Science of The Total Environment, 1992Co-Authors: R. Steiman, Jean-louis Benoit-guyod, F. Seigle-murandi, Bartisetiani MuntalifAbstract:Abstract A wide study has been conducted on the fate of xenobiotics in the environment and more particularly on the biodegradation of these compounds. The selection of fungal strains able to degrade Pentachloronitrobenzene (PCNB) has been performed. Of the collection of strains in our laboratory 1060 were incubated with PCNB (100 mg/l) for 5 days in liquid synthetic medium. The production of extracellular phenoloxidases was examined by using ten different reagents. We found that only 3% of the strains were able to degrade PCNB by over 70%. The most performant groups were Mucedinaceeae and Zygomycetes. No correlation was found between the production of extracellular phenoloxidases and the biodegradative capability of individual strains. A detailed study of PCNB metabolism by selected strains is in progress.
R. Steiman - One of the best experts on this subject based on the ideXlab platform.
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Relationship between the biodegradative capability of soil micromycetes for pentachlorophenol and for Pentachloronitrobenzene.
The Science of the total environment, 1992Co-Authors: F. Seigle-murandi, Jean-louis Benoit-guyod, R. Steiman, Bartisetiani Muntalif, Lucile SageAbstract:A collection of 1056 strains in our laboratory were incubated with various xenobiotics among which were two potent fungicides: pentachlorophenol (PCP) and Pentachloronitrobenzene (PCNB). The production of extracellular phenoloxidases were examined, using a series of ten different reagents. On the whole, PCNB is less accessible to fungal degradation than PCP. Although no correlation was found between the biodegradative capability of individual fungal strains for PCP or for PCNB, when taxonomic groups were considered as a whole, the same activity profiles were found. Zygomycetes were the most efficient; yeasts the least efficient towards both substrates. A more detailed study of the metabolism of both substrates on selected strains is in progress.
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Degradation of Pentachloronitrobenzene by micromycetes isolated from soil
Science of The Total Environment, 1992Co-Authors: R. Steiman, Jean-louis Benoit-guyod, F. Seigle-murandi, Bartisetiani MuntalifAbstract:Abstract A wide study has been conducted on the fate of xenobiotics in the environment and more particularly on the biodegradation of these compounds. The selection of fungal strains able to degrade Pentachloronitrobenzene (PCNB) has been performed. Of the collection of strains in our laboratory 1060 were incubated with PCNB (100 mg/l) for 5 days in liquid synthetic medium. The production of extracellular phenoloxidases was examined by using ten different reagents. We found that only 3% of the strains were able to degrade PCNB by over 70%. The most performant groups were Mucedinaceeae and Zygomycetes. No correlation was found between the production of extracellular phenoloxidases and the biodegradative capability of individual strains. A detailed study of PCNB metabolism by selected strains is in progress.