The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform
Fabio Fava - One of the best experts on this subject based on the ideXlab platform.
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Soya lecithin effects on the aerobic biodegradation of polychlorinated biphenyls in an artificially contaminated soil.
Biotechnology and bioengineering, 2001Co-Authors: Fabio Fava, Diana Di GioiaAbstract:The effects of the phytogenic surfactant soya lecithin (SL) on the aerobic biodegradation of polychlorinated biphenyls (PCBs) spiked into a synthetic soil were studied. Soil was spiked with both biphenyl (4 g/kg) and Fenclor 42 (1,000 mg/kg) and treated in aerobic batch slurry-phase microcosms (17.5% w/v). Microcosms were prepared either with or without the exogenous aerobic PCB-dechlorinating bacterial co-culture ECO3 (inoculum:10(8) CFU/mL). In some inoculated microcosms, SL was added at 15 or 30 g/kg. Indigenous bacteria having the capability of metabolizing biphenyl and 2-Chlorobenzoic Acid were found to develop in the microcosms during the experiment, and were responsible for the significant PCB biodegradation and dechlorination observed in the uninoculated controls. The addition of ECO3 bacteria resulted in only a slight PCB biodegradation increase. In the presence of SL, a higher availability of biphenyl- and chlorobenzoic Acid-degrading bacteria and higher PCB biodegradation and dechlorination yields were observed; the effects increased proportionally with the concentration of the applied SL. A significant decrease of soil ecotoxicity was also revealed in SL-supplemented microcosms. At both concentrations, SL was found to be a good carbon source for both the indigenous and ECO3 bacteria, as well as a product capable of enhancing the PCB bioavailability in the microcosms.
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Characterization of catechol- and chlorocatechol-degrading activity in the ortho-chlorinated benzoic Acid-degrading Pseudomonas sp. CPE2 strain
Research in microbiology, 1998Co-Authors: Diana Di Gioia, Fabio Fava, F. Baldoni, Leonardo MarchettiAbstract:Pyrocatechase activity was studied in the Pseudomonas sp. CPE2 strain, which is capable of growing on 2-Chlorobenzoic and 2,5-dichlorobenzoic Acid, giving rise to catechol and 4-chlorocatechol, respectively, as intermediate metabolites. The CPE2 crude extract was found to metabolize both catechol and 4-chlorocatechol. Enzymatic as well as phenotypic studies performed both on this strain and on a mutant strain lacking the chlorocatechol-degrading genes were consistent with the presence of two catechol-cleaving enzymes, one active mainly against catechol (pyrocatechase I) and the other with broader substrate specificity (pyrocatechase II). The latter enzyme also appeared to be induced when CPE2 cells were grown on 2-Chlorobenzoic Acid, thus contributing to catechol metabolism, in addition to pyrocatechase I. Despite the presence of a large plasmid in CPE2 cells, the chlorocatechol-degrading genes, highly homologous to the cls operon, were located on the chromosome. The selection at relatively high frequency of mutant strains with altered growth capabilities and which lacked the chlorocatechol-degrading genes suggests a transposon-like character for these catabolic genes in the CPE2 strain.
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2‐Chlorobenzoic Acid and 2,5‐dichlorobenzoic Acid metabolism by crude extracts of Pseudomonas sp. CPE2 strain
Letters in applied microbiology, 1996Co-Authors: Fabio Fava, F. Baldoni, Leonardo MarchettiAbstract:Crude extracts of Pseudomonas sp. CPE2 strain, which is capable of growing on 2-Chlorobenzoic Acid (2-CBA) and 2,5-dichlorobenzoic Acid (2,5-dCBA) in the absence of other carbon sources, were found to be capable of bioconverting 2-CBA and 2,5-dCBA to catechol and 4-chlorocatechol, respectively, by a reaction requiring molecular oxygen and exogenous NADH. Extracts obtained from 2-CBA-grown cells in the presence of 2-CBA and from 2,5-dCBA-grown cells in the presence of 2,5-dCBA were found to have activities similarly influenced by the assay parameters pH, temperature, and by concentration of oxygen, protein, Fe2+, FAD and NADH in the assay medium. In addition, the activity of the two crude extracts in the presence of 2-CBA or 2,5-dCBA was described by very similar Michaelis-Menten kinetic parameters. These observations led to the speculation that a unique broad-spectrum chlorobenzoate 1,2-dioxygenase catalyses the 2-CBA and 2,5-dCBA metabolism both in 2-CBA- and 2,5-dCBA-grown CPE2 cells.
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Effect of yeast extract on growth kinetics during aerobic biodegradation of chlorobenzoic Acids.
Biotechnology and bioengineering, 1995Co-Authors: Piero M. Armenante, Fabio Fava, David KafkewitzAbstract:The Monod or Andrews kinetic parameters describing the growth of Pseudomonas sp. CPE2 strain on 2,5-dich!orobenzoic Acid and 2-Chlorobenzoic Acid, and Al-caligenes sp. CPE3 strain on 3,4-dichlorobenzoic Acid, 4-chlorobenzoic Acid, and 3-chlorobenzoic Acid were determined from batch and continuous growth experiments conducted in the presence or absence of yeast extract (50 mg/L). Strain CPE2 displayed inhibitory growth kinetics in the absence of yeast extract and a noninhibitory kinetics in the presence of yeast extract. Similar results were obtained for CPE3. The presence of yeast extract also resulted in a significant increase in the affinity of the strains for the chlorobenzoic Acids they degraded. © 1995 John Wiley & Sons, Inc.
Leonardo Marchetti - One of the best experts on this subject based on the ideXlab platform.
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Characterization of catechol- and chlorocatechol-degrading activity in the ortho-chlorinated benzoic Acid-degrading Pseudomonas sp. CPE2 strain
Research in microbiology, 1998Co-Authors: Diana Di Gioia, Fabio Fava, F. Baldoni, Leonardo MarchettiAbstract:Pyrocatechase activity was studied in the Pseudomonas sp. CPE2 strain, which is capable of growing on 2-Chlorobenzoic and 2,5-dichlorobenzoic Acid, giving rise to catechol and 4-chlorocatechol, respectively, as intermediate metabolites. The CPE2 crude extract was found to metabolize both catechol and 4-chlorocatechol. Enzymatic as well as phenotypic studies performed both on this strain and on a mutant strain lacking the chlorocatechol-degrading genes were consistent with the presence of two catechol-cleaving enzymes, one active mainly against catechol (pyrocatechase I) and the other with broader substrate specificity (pyrocatechase II). The latter enzyme also appeared to be induced when CPE2 cells were grown on 2-Chlorobenzoic Acid, thus contributing to catechol metabolism, in addition to pyrocatechase I. Despite the presence of a large plasmid in CPE2 cells, the chlorocatechol-degrading genes, highly homologous to the cls operon, were located on the chromosome. The selection at relatively high frequency of mutant strains with altered growth capabilities and which lacked the chlorocatechol-degrading genes suggests a transposon-like character for these catabolic genes in the CPE2 strain.
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2‐Chlorobenzoic Acid and 2,5‐dichlorobenzoic Acid metabolism by crude extracts of Pseudomonas sp. CPE2 strain
Letters in applied microbiology, 1996Co-Authors: Fabio Fava, F. Baldoni, Leonardo MarchettiAbstract:Crude extracts of Pseudomonas sp. CPE2 strain, which is capable of growing on 2-Chlorobenzoic Acid (2-CBA) and 2,5-dichlorobenzoic Acid (2,5-dCBA) in the absence of other carbon sources, were found to be capable of bioconverting 2-CBA and 2,5-dCBA to catechol and 4-chlorocatechol, respectively, by a reaction requiring molecular oxygen and exogenous NADH. Extracts obtained from 2-CBA-grown cells in the presence of 2-CBA and from 2,5-dCBA-grown cells in the presence of 2,5-dCBA were found to have activities similarly influenced by the assay parameters pH, temperature, and by concentration of oxygen, protein, Fe2+, FAD and NADH in the assay medium. In addition, the activity of the two crude extracts in the presence of 2-CBA or 2,5-dCBA was described by very similar Michaelis-Menten kinetic parameters. These observations led to the speculation that a unique broad-spectrum chlorobenzoate 1,2-dioxygenase catalyses the 2-CBA and 2,5-dCBA metabolism both in 2-CBA- and 2,5-dCBA-grown CPE2 cells.
Diana Di Gioia - One of the best experts on this subject based on the ideXlab platform.
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Soya lecithin effects on the aerobic biodegradation of polychlorinated biphenyls in an artificially contaminated soil.
Biotechnology and bioengineering, 2001Co-Authors: Fabio Fava, Diana Di GioiaAbstract:The effects of the phytogenic surfactant soya lecithin (SL) on the aerobic biodegradation of polychlorinated biphenyls (PCBs) spiked into a synthetic soil were studied. Soil was spiked with both biphenyl (4 g/kg) and Fenclor 42 (1,000 mg/kg) and treated in aerobic batch slurry-phase microcosms (17.5% w/v). Microcosms were prepared either with or without the exogenous aerobic PCB-dechlorinating bacterial co-culture ECO3 (inoculum:10(8) CFU/mL). In some inoculated microcosms, SL was added at 15 or 30 g/kg. Indigenous bacteria having the capability of metabolizing biphenyl and 2-Chlorobenzoic Acid were found to develop in the microcosms during the experiment, and were responsible for the significant PCB biodegradation and dechlorination observed in the uninoculated controls. The addition of ECO3 bacteria resulted in only a slight PCB biodegradation increase. In the presence of SL, a higher availability of biphenyl- and chlorobenzoic Acid-degrading bacteria and higher PCB biodegradation and dechlorination yields were observed; the effects increased proportionally with the concentration of the applied SL. A significant decrease of soil ecotoxicity was also revealed in SL-supplemented microcosms. At both concentrations, SL was found to be a good carbon source for both the indigenous and ECO3 bacteria, as well as a product capable of enhancing the PCB bioavailability in the microcosms.
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Characterization of catechol- and chlorocatechol-degrading activity in the ortho-chlorinated benzoic Acid-degrading Pseudomonas sp. CPE2 strain
Research in microbiology, 1998Co-Authors: Diana Di Gioia, Fabio Fava, F. Baldoni, Leonardo MarchettiAbstract:Pyrocatechase activity was studied in the Pseudomonas sp. CPE2 strain, which is capable of growing on 2-Chlorobenzoic and 2,5-dichlorobenzoic Acid, giving rise to catechol and 4-chlorocatechol, respectively, as intermediate metabolites. The CPE2 crude extract was found to metabolize both catechol and 4-chlorocatechol. Enzymatic as well as phenotypic studies performed both on this strain and on a mutant strain lacking the chlorocatechol-degrading genes were consistent with the presence of two catechol-cleaving enzymes, one active mainly against catechol (pyrocatechase I) and the other with broader substrate specificity (pyrocatechase II). The latter enzyme also appeared to be induced when CPE2 cells were grown on 2-Chlorobenzoic Acid, thus contributing to catechol metabolism, in addition to pyrocatechase I. Despite the presence of a large plasmid in CPE2 cells, the chlorocatechol-degrading genes, highly homologous to the cls operon, were located on the chromosome. The selection at relatively high frequency of mutant strains with altered growth capabilities and which lacked the chlorocatechol-degrading genes suggests a transposon-like character for these catabolic genes in the CPE2 strain.
Maite L. Docampo - One of the best experts on this subject based on the ideXlab platform.
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Ultrasound‐Promoted Reaction of 2‐Chlorobenzoic Acids and Aliphatic Amines
European Journal of Organic Chemistry, 2007Co-Authors: Maite L. Docampo, Rolando F. Pellón, Ana Estévez-braun, Angel G. RaveloAbstract:An improvement to the use of DMF as a solvent for the condensation of 2-Chlorobenzoic Acids with aliphatic primary or secondary amines was described. A number of alkylaminobenzoic Acids and dialkylaminobenzoic Acids were synthesized in acceptable-to-good yield. The advantages of this procedure include readily available substrates, the use of an inexpensive copper powder without taking any precautions to exclude moisture under mild conditions and experimental ease. Furthermore, this condensation could also be achieved under nonclassical conditions by using ultrasonic irradiation at room temperature. We demonstrated that ultrasound-promoted condensation of 2-Chlorobenzoic Acid with aliphatic amines with the use of DMF as the solvent, especially in the case of secondary amines, affords products in high yields and reduces the reaction time to minutes. The results proved to be highly reproducible because the relevant sonochemical parameters were rigorously controlled.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
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synthesis of 9 methyl 11h pyrido 2 1 b quinazolin 11 one using the ullmann condensation
Synthetic Communications, 2006Co-Authors: Rolando F. Pellón, Maite L. Docampo, Victoria Gomez, Zulfia Kunakbaeva, Herman VelezcastroAbstract:Abstract The Ullmann condensation between 2‐chlorobenzoic Acid and 2‐amino‐6‐methyl pyridine in DMF as solvent yielded 2‐[(6‐methyl‐2‐pyridinyl)amino] benzoic Acid. The cyclization of this Acid gave two isomers, the 9‐methyl‐11H‐pyrido[2,1‐b]quinazolin‐11‐one and, in a minor quantity, 2‐methylbenzo[b][1,8]naphtyridin‐5(10H)‐one. Using ultrasound irradiation the pyridoquinazolin‐11‐one was obtained as the sole product.
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Microwave-assisted synthesis of 2-phenoxybenzoic Acids
Journal of Chemical Research, 2006Co-Authors: Rolando F. Pellón, Ana Martin, Maite L. Docampo, Miriam Mesa, Victoria GomezAbstract:Substituted 2-phenoxybenzoic Acid derivatives were synthesised in high yield and in short reaction times using the Ullmann condensation of 2-Chlorobenzoic Acid with phenol derivatives under microwave irradiation in dry media.
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Synthesis of 9‐Methyl‐11H‐pyrido[2,1‐b]quinazolin‐11‐one Using the Ullmann Condensation
Synthetic Communications, 2006Co-Authors: Rolando F. Pellón, Maite L. Docampo, Victoria Gomez, Zulfia Kunakbaeva, Herman Velez-castroAbstract:Abstract The Ullmann condensation between 2‐chlorobenzoic Acid and 2‐amino‐6‐methyl pyridine in DMF as solvent yielded 2‐[(6‐methyl‐2‐pyridinyl)amino] benzoic Acid. The cyclization of this Acid gave two isomers, the 9‐methyl‐11H‐pyrido[2,1‐b]quinazolin‐11‐one and, in a minor quantity, 2‐methylbenzo[b][1,8]naphtyridin‐5(10H)‐one. Using ultrasound irradiation the pyridoquinazolin‐11‐one was obtained as the sole product.
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Microwave-assisted synthesis of N-phenylanthranilic Acids in water
Journal of Chemical Research, 2005Co-Authors: Ana Martin, Rolando F. Pellón, Maite L. Docampo, Miriam Mesa, Victoria GomezAbstract:N-Phenylanthranilic Acid derivatives were synthesised using the Ullmann condensation of 2-Chlorobenzoic Acid with aniline derivatives under microwave irradiation in aqueous media. The method offers better yields in shorter reaction times compared to classical heating approaches using water as solvent.
Abir Al-tabbaa - One of the best experts on this subject based on the ideXlab platform.
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Utilisation of Magnesium Phosphate Cements to Facilitate Biodegradation within a Stabilised/Solidified Contaminated Soil
Water Air & Soil Pollution, 2011Co-Authors: Reginald B Kogbara, Abir Al-tabbaa, Srinath R IyengarAbstract:Stabilisation/solidification (S/S) of heavy metals and a parallel biodegradation of an organic contaminant using magnesium phosphate cements (MPC) was investigated under laboratory conditions. The study was aimed at improving the robustness of S/S technology by encouraging biodegradation in order to bring about some form of contaminant attenuation over time. A silty sand soil, amended with compost was spiked with an organic contaminant, 2-Chlorobenzoic Acid (2CBA), and two heavy metal compounds, lead nitrate and zinc chloride. Two formulations of the MPC grouts based on different proportions of the cement constituents, with paste pH of approximately 6.5 and 10, were utilised for S/S treatment. The study involved treating the organic contaminant present in the soil with and without the heavy metals by employing the low and high pH MPC grout mixes, and using 10% and 25% compost content. Microbial activity was monitored using dehydrogenase assay, whilst the tests pertaining to the performance criteria such as contaminant concentration, unconfined compressive strength, elastic stiffness, permeability and batch leaching tests were evaluated at set periods. Contaminant recovery analysis after 140 days indicated a similar reduction in 2CBA concentration to approximately 56% in the different grout mixes. The cement constituents exhibited stimulatory and inhibitory effects on soil dehydrogenase activity. Heavy metal leachability as well as the engineering behaviour of the treated soils conformed to acceptable standards. The results of the investigations show considerable promise for the application of MPC in contaminated land remediation.
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Degradation of 2-Chlorobenzoic Acid in stabilised/solidified soil systems
International Biodeterioration & Biodegradation, 2008Co-Authors: Michael John Harbottle, Abir Al-tabbaaAbstract:The possibility of facilitating organic contaminant biodegradation within eight different stabilised/solidified soil systems was investigated. Two soils, a silty sand and clayey silt contaminated with 2-Chlorobenzoic Acid, were mixed with two different grouts; Portland cement grout and a magnesium phosphate cement grout. The effect of a soil amendment (green waste compost) was examined. Biological activity was monitored using plate counts and dehydrogenase activity. After 106 days, contamination within the silty sand soil/Portland cement mix was reduced by approximately 60% on average, and by over 95% on average with compost addition. Cement grout addition gave substantial changes in the microbial communities present, with Portland cement leading to initial decreases in microbial numbers (by up to a factor of 104) but with a corresponding increase in dehydrogenase activity (by 250% with added compost). Subsequently, microbial numbers increased and the dehydrogenase activity reduced to negligible levels. Magnesium phosphate cement addition led to a decrease in the presence of bacteria and an increase in fungi, whilst with added compost high levels of dehydrogenase activity were maintained for 106 days. It is concluded that contaminant degradation can occur in stabilised/solidified soil systems, but the role of microbes in this removal is not certain.