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James E. Mcgrath - One of the best experts on this subject based on the ideXlab platform.
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the membrane electrode interface in pefcs ii impact on fuel cell durability
Journal of The Electrochemical Society, 2010Co-Authors: Yu Seung Kim, James E. Mcgrath, Melinda L Einsla, Bryan S PivovarAbstract:The impact of the membrane-electrode interface on fuel cell durability was investigated in polymer electrolyte fuel cells (PEFCs). Cells using disulfonated poly(arylene ether) copolymer (BPSH) membranes exhibited greater performance loss than a cell using Nafion after 700 h of direct methanol fuel cell (DMFC) testing. Additionally, the performance loss and cell resistance within the BPSH family, of copolymers increased with increasing degree of disulfonation. Membrane characterization using 1 H NMR, potentiometric titration, intrinsic viscosity, water uptake, and proton conductivity showed minimal impact from chemical/physical changes. Fuel cell performance degradation scaled well with initial membrane-electrode interfacial resistance, suggesting that the membrane-electrode interface was an important contributor to DMFC durability. These results are of particular interest for alternative proton exchange membranes where interfacial compatibility with electrodes is a critical, unresolved issue.
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sulfonated poly arylene ether sulfone copolymer proton exchange membranes composition and morphology effects on the methanol permeability
Journal of Membrane Science, 2004Co-Authors: Yu Seung Kim, Michael A Hickner, Limin Dong, Bryan S Pivovar, James E. McgrathAbstract:Abstract Methanol permeability of directly copolymerized 4,4′-biphenol based disulfonated poly(arylene ether sulfone) copolymers (BPSH) was investigated with reference to utility as a proton exchange membrane (PEM) for direct methanol fuel cells (DMFC). Water uptake and dynamic mechanical analysis were coupled with previous observations that the PEM can have two functional morphological regimes, which depend on the degree of disulfonation (copolymer composition), acidification method, and hydrothermal treatment. The two regimes are observed by AFM to represent: (1) a “closed” structure where the hydrophilic copolymer chain segments essentially aggregate as isolated domains; or (2) an “open” structure where the domain connectivity of the hydrophilic phase of the copolymers is achieved. It was demonstrated that methanol permeability (25 °C) of the copolymers abruptly increased at copolymer compositions and processing conditions that influenced the membrane morphology to change from a closed to a much more open structure. The activation energy in the closed structure regime, ∼20 kJ/mol, was about 35% higher than that in the open regime, ∼15 kJ/mol. The BPSH copolymers had higher selectivity (i.e. proton conductivity/permeability) than Nafion because of their remarkably lower methanol permeability, suggesting these materials hold promise for improved DMFC performance. Selectivity increased with the degree of disulfonation in closed structures, but decreased in the open structure regime. It is suggested that the optimum concentration of proton conducting groups for DMFC should be observed at or near the percolation threshold.
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processing induced morphological development in hydrated sulfonated poly arylene ether sulfone copolymer membranes
Polymer, 2003Co-Authors: Yu Seung Kim, Michael A Hickner, Limin Dong, Bryan S Pivovar, James E. McgrathAbstract:Abstract The development of morphological solid-state structures in sulfonated poly(arylene ether sulfone) copolymers (acid form) by hydrothermal treatment was investigated by water uptake, dynamic mechanical analysis (DMA), and tapping mode atomic force microscopy (TM-AFM). The water uptake and DMA studies suggested that the materials have three irreversible morphological regimes, whose intervals are controlled by copolymer composition and hydrothermal treatment temperature. Ambient temperature treatment of the membranes afforded a structure denoted as Regime1 . When the copolymer membranes were exposed to a higher temperature, AFM revealed a morphology ( Regime2 ) where the phase contrast and domain connectivity of the hydrophilic phase of the copolymers were greatly increased. A yet higher treatment temperature was defined which yielded a third regime, likely related to viscoelastic relaxations associated with the hydrated glass transition temperature (hydrated T g ). The required temperatures needed to produce transitions from Regime1 to Regime2 or Regime3 decreased with increasing degree of disulfonation. These temperatures correspond to the percolation and hydrogel temperatures, respectively. Poly(arylene ether sulfone) copolymer membranes with a 40% disulfonation in Regime2 under fully hydrated conditions showed similar proton conductivity (∼0.1 S/cm) to the well-known perfluorinated copolymer Nafion ® 1135 but exhibited higher modulus and water uptake. The proton conductivity and storage modulus are discussed in terms of each of the morphological regimes and compared with Nafion 1135. The results are of particular interest for either hydrogen or direct methanol fuel cells where conductivity and membrane permeability are critical issues.
Yu Seung Kim - One of the best experts on this subject based on the ideXlab platform.
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the membrane electrode interface in pefcs ii impact on fuel cell durability
Journal of The Electrochemical Society, 2010Co-Authors: Yu Seung Kim, James E. Mcgrath, Melinda L Einsla, Bryan S PivovarAbstract:The impact of the membrane-electrode interface on fuel cell durability was investigated in polymer electrolyte fuel cells (PEFCs). Cells using disulfonated poly(arylene ether) copolymer (BPSH) membranes exhibited greater performance loss than a cell using Nafion after 700 h of direct methanol fuel cell (DMFC) testing. Additionally, the performance loss and cell resistance within the BPSH family, of copolymers increased with increasing degree of disulfonation. Membrane characterization using 1 H NMR, potentiometric titration, intrinsic viscosity, water uptake, and proton conductivity showed minimal impact from chemical/physical changes. Fuel cell performance degradation scaled well with initial membrane-electrode interfacial resistance, suggesting that the membrane-electrode interface was an important contributor to DMFC durability. These results are of particular interest for alternative proton exchange membranes where interfacial compatibility with electrodes is a critical, unresolved issue.
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sulfonated poly arylene ether sulfone copolymer proton exchange membranes composition and morphology effects on the methanol permeability
Journal of Membrane Science, 2004Co-Authors: Yu Seung Kim, Michael A Hickner, Limin Dong, Bryan S Pivovar, James E. McgrathAbstract:Abstract Methanol permeability of directly copolymerized 4,4′-biphenol based disulfonated poly(arylene ether sulfone) copolymers (BPSH) was investigated with reference to utility as a proton exchange membrane (PEM) for direct methanol fuel cells (DMFC). Water uptake and dynamic mechanical analysis were coupled with previous observations that the PEM can have two functional morphological regimes, which depend on the degree of disulfonation (copolymer composition), acidification method, and hydrothermal treatment. The two regimes are observed by AFM to represent: (1) a “closed” structure where the hydrophilic copolymer chain segments essentially aggregate as isolated domains; or (2) an “open” structure where the domain connectivity of the hydrophilic phase of the copolymers is achieved. It was demonstrated that methanol permeability (25 °C) of the copolymers abruptly increased at copolymer compositions and processing conditions that influenced the membrane morphology to change from a closed to a much more open structure. The activation energy in the closed structure regime, ∼20 kJ/mol, was about 35% higher than that in the open regime, ∼15 kJ/mol. The BPSH copolymers had higher selectivity (i.e. proton conductivity/permeability) than Nafion because of their remarkably lower methanol permeability, suggesting these materials hold promise for improved DMFC performance. Selectivity increased with the degree of disulfonation in closed structures, but decreased in the open structure regime. It is suggested that the optimum concentration of proton conducting groups for DMFC should be observed at or near the percolation threshold.
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processing induced morphological development in hydrated sulfonated poly arylene ether sulfone copolymer membranes
Polymer, 2003Co-Authors: Yu Seung Kim, Michael A Hickner, Limin Dong, Bryan S Pivovar, James E. McgrathAbstract:Abstract The development of morphological solid-state structures in sulfonated poly(arylene ether sulfone) copolymers (acid form) by hydrothermal treatment was investigated by water uptake, dynamic mechanical analysis (DMA), and tapping mode atomic force microscopy (TM-AFM). The water uptake and DMA studies suggested that the materials have three irreversible morphological regimes, whose intervals are controlled by copolymer composition and hydrothermal treatment temperature. Ambient temperature treatment of the membranes afforded a structure denoted as Regime1 . When the copolymer membranes were exposed to a higher temperature, AFM revealed a morphology ( Regime2 ) where the phase contrast and domain connectivity of the hydrophilic phase of the copolymers were greatly increased. A yet higher treatment temperature was defined which yielded a third regime, likely related to viscoelastic relaxations associated with the hydrated glass transition temperature (hydrated T g ). The required temperatures needed to produce transitions from Regime1 to Regime2 or Regime3 decreased with increasing degree of disulfonation. These temperatures correspond to the percolation and hydrogel temperatures, respectively. Poly(arylene ether sulfone) copolymer membranes with a 40% disulfonation in Regime2 under fully hydrated conditions showed similar proton conductivity (∼0.1 S/cm) to the well-known perfluorinated copolymer Nafion ® 1135 but exhibited higher modulus and water uptake. The proton conductivity and storage modulus are discussed in terms of each of the morphological regimes and compared with Nafion 1135. The results are of particular interest for either hydrogen or direct methanol fuel cells where conductivity and membrane permeability are critical issues.
Alasdair M Cook - One of the best experts on this subject based on the ideXlab platform.
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Desulfonation and Degradation of the Disulfodiphenylethercarboxylates from Linear
2016Co-Authors: Alkyldiphenyletherdisulfonate Surfactants, David Schleheck, Melanie Lechner, Marc -f. J. Suter, Alasdair M CookAbstract:Earlier work showed that the biodegradation of a commercial linear monoalkyldiphenyletherdisulfonate surfactant as a carbon source for microbial growth leads to the quantitative formation of corresponding disulfodiphenylether carboxylates (DSDPECs), which were not degraded. -Proteobacterium strain DS-1 (DSM 13023) catalyzes these reactions. These DSDPECs have now been characterized by high-pressure liquid chromatography coupled via an electrospray interface to a mass spectrometer. DSDPECs were a complex mixture of compounds which indicated catabolism via -oxygenation and -oxidation. DSDPECs were subject to quantitative Desulfonation in bacterial cultures in which they served as sole sulfur sources for bacterial growth. On average, one sulfonate group per DSDPEC species was removed, and the organism responsible for this Desulfonation was isolated and identified as Rhodococcus opacus ISO-5. The products were largely mono-sulfodiphenylether carboxylate-phenols (MSDPEC-phenols). MSDPEC-phenols were subject to extensive dis-similation by bacteria from activated sludge. The linear monoalkyldiphenyletherdisulfonate surfactants (LADPEDS) (Fig. 1) have been in use for some 40 years in industrial processes (22), which include the production of syn-thetic latex and its use in carpet production, paints, and pape
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Desulfonation and degradation of the disulfodiphenylethercarboxylates from linear alkyldiphenyletherdisulfonate surfactants
Applied and Environmental Microbiology, 2003Co-Authors: David Schleheck, Melanie Lechner, Rene Schonenberger, M Suter, Alasdair M CookAbstract:Earlier work showed that the biodegradation of a commercial linear monoalkyldiphenyletherdisulfonate surfactant as a carbon source for microbial growth leads to the quantitative formation of corresponding disulfodiphenylether carboxylates (DSDPECs), which were not degraded. -Proteobacterium strain DS-1 (DSM 13023) catalyzes these reactions. These DSDPECs have now been characterized by high-pressure liquid chromatography coupled via an electrospray interface to a mass spectrometer. DSDPECs were a complex mixture of compounds which indicated catabolism via -oxygenation and -oxidation. DSDPECs were subject to quantitative Desulfonation in bacterial cultures in which they served as sole sulfur sources for bacterial growth. On average, one sulfonate group per DSDPEC species was removed, and the organism responsible for this Desulfonation was isolated and identified as Rhodococcus opacus ISO-5. The products were largely monosulfodiphenylether carboxylate-phenols (MSDPEC-phenols). MSDPEC-phenols were subject to extensive dissimilation by bacteria from activated sludge.
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Desulfonation of biotransformation products from commercial linear alkylbenzenesulfonates
Environmental Toxicology and Chemistry, 1998Co-Authors: Jorg Mampel, Tanja Hitzler, Axel Ritter, Alasdair M CookAbstract:Earlier work shows that the biodegradation and biotransformation of commercial linear alkylbenzenesulfonate (LAS) as a carbon source for growth leads to a residue of sulfonated aromatic compounds, termed refractory organic carbon, from the synthetic by-products. We now show that this refractory organic carbon, after separation from sulfate ion, is utilized extensively as a sulfur source for bacterial growth. The products of Desulfonation are expected to be biodegradable, so we question the value of adjectives like refractory.
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anaerobic Desulfonation of 4 tolylsulfonate and 2 4 sulfophenyl butyrate by a clostridium sp
Applied and Environmental Microbiology, 1996Co-Authors: Karin Denger, Michael A. Kertesz, Esther H Vock, Roberto Schon, Andreas Magli, Alasdair M CookAbstract:Alkyl- and arylsulfonates were tested as sole added sources of sulfur for the growth of enrichment cultures under strictly anaerobic denitrifying or fermentative conditions. Cultures that utilized taurine, ethylsulfonate, the dyestuffs orange II and acid red I, tolylsulfonate, 2-(4-sulfophenyl)butyrate (SPB), a dialkyltetralinesulfonate, and 1-(4-sulfophenyl)octane were readily obtained. We chose to work with the simple aromatic compounds and isolated a fermentative bacterium, strain EV4, which utilized SPB as the sole added source of sulfur in glucose-mineral medium. The organism was identified as a Clostridium sp. related to Clostridium beijerinckii. Clostridium sp. strain EV4 utilized seven of seven tested arylsulfonates quantitatively. The growth yield was about 3 kg of protein per mol of sulfur, whether sulfonate or sulfate was utilized. A major product specific to each sulfonate could be observed. Although no product was identified, the existence of anaerobic Desulfonation has been established.
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bacterial Desulfonation of the ethanesulfonate metabolite of the chloroacetanilide herbicide metazachlor
Environmental Science & Technology, 1996Co-Authors: Heike Laue, Jennifer A Field, Alasdair M CookAbstract:Metazachlor (R-CH2-Cl), a chloroacetanilide herbicide, is converted in soil to products including the ethanesulfonate metabolite (R-CH2-SO3-; BH 479-8). Nothing is known about the degradation of the ethanesulfonates of this class of herbicides. We used inocula derived from five sources for enrichment cultures to utilize R-CH2-SO3- as a sole sulfur source for the growth of microorganisms. Each culture yielded bacteria that caused the disappearance of R-CH2-SO3- and the formation of a product identified as the glycolate metabolite (R-CH2-OH; BH 479-1) by mass spectrometry. A pure culture, strain HL1, was isolated, and this bacterium quantitatively desulfonated R-CH2-SO3-, the sulfur being recovered in cell protein. Recovery of the organic moiety was usually about 80%. A second ethanesulfonate (R‘-CH2-SO3-) and two alkylsulfonates, but not taurine, were utilized by strain HL1 as sulfur sources.
Bryan S Pivovar - One of the best experts on this subject based on the ideXlab platform.
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the membrane electrode interface in pefcs ii impact on fuel cell durability
Journal of The Electrochemical Society, 2010Co-Authors: Yu Seung Kim, James E. Mcgrath, Melinda L Einsla, Bryan S PivovarAbstract:The impact of the membrane-electrode interface on fuel cell durability was investigated in polymer electrolyte fuel cells (PEFCs). Cells using disulfonated poly(arylene ether) copolymer (BPSH) membranes exhibited greater performance loss than a cell using Nafion after 700 h of direct methanol fuel cell (DMFC) testing. Additionally, the performance loss and cell resistance within the BPSH family, of copolymers increased with increasing degree of disulfonation. Membrane characterization using 1 H NMR, potentiometric titration, intrinsic viscosity, water uptake, and proton conductivity showed minimal impact from chemical/physical changes. Fuel cell performance degradation scaled well with initial membrane-electrode interfacial resistance, suggesting that the membrane-electrode interface was an important contributor to DMFC durability. These results are of particular interest for alternative proton exchange membranes where interfacial compatibility with electrodes is a critical, unresolved issue.
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sulfonated poly arylene ether sulfone copolymer proton exchange membranes composition and morphology effects on the methanol permeability
Journal of Membrane Science, 2004Co-Authors: Yu Seung Kim, Michael A Hickner, Limin Dong, Bryan S Pivovar, James E. McgrathAbstract:Abstract Methanol permeability of directly copolymerized 4,4′-biphenol based disulfonated poly(arylene ether sulfone) copolymers (BPSH) was investigated with reference to utility as a proton exchange membrane (PEM) for direct methanol fuel cells (DMFC). Water uptake and dynamic mechanical analysis were coupled with previous observations that the PEM can have two functional morphological regimes, which depend on the degree of disulfonation (copolymer composition), acidification method, and hydrothermal treatment. The two regimes are observed by AFM to represent: (1) a “closed” structure where the hydrophilic copolymer chain segments essentially aggregate as isolated domains; or (2) an “open” structure where the domain connectivity of the hydrophilic phase of the copolymers is achieved. It was demonstrated that methanol permeability (25 °C) of the copolymers abruptly increased at copolymer compositions and processing conditions that influenced the membrane morphology to change from a closed to a much more open structure. The activation energy in the closed structure regime, ∼20 kJ/mol, was about 35% higher than that in the open regime, ∼15 kJ/mol. The BPSH copolymers had higher selectivity (i.e. proton conductivity/permeability) than Nafion because of their remarkably lower methanol permeability, suggesting these materials hold promise for improved DMFC performance. Selectivity increased with the degree of disulfonation in closed structures, but decreased in the open structure regime. It is suggested that the optimum concentration of proton conducting groups for DMFC should be observed at or near the percolation threshold.
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processing induced morphological development in hydrated sulfonated poly arylene ether sulfone copolymer membranes
Polymer, 2003Co-Authors: Yu Seung Kim, Michael A Hickner, Limin Dong, Bryan S Pivovar, James E. McgrathAbstract:Abstract The development of morphological solid-state structures in sulfonated poly(arylene ether sulfone) copolymers (acid form) by hydrothermal treatment was investigated by water uptake, dynamic mechanical analysis (DMA), and tapping mode atomic force microscopy (TM-AFM). The water uptake and DMA studies suggested that the materials have three irreversible morphological regimes, whose intervals are controlled by copolymer composition and hydrothermal treatment temperature. Ambient temperature treatment of the membranes afforded a structure denoted as Regime1 . When the copolymer membranes were exposed to a higher temperature, AFM revealed a morphology ( Regime2 ) where the phase contrast and domain connectivity of the hydrophilic phase of the copolymers were greatly increased. A yet higher treatment temperature was defined which yielded a third regime, likely related to viscoelastic relaxations associated with the hydrated glass transition temperature (hydrated T g ). The required temperatures needed to produce transitions from Regime1 to Regime2 or Regime3 decreased with increasing degree of disulfonation. These temperatures correspond to the percolation and hydrogel temperatures, respectively. Poly(arylene ether sulfone) copolymer membranes with a 40% disulfonation in Regime2 under fully hydrated conditions showed similar proton conductivity (∼0.1 S/cm) to the well-known perfluorinated copolymer Nafion ® 1135 but exhibited higher modulus and water uptake. The proton conductivity and storage modulus are discussed in terms of each of the morphological regimes and compared with Nafion 1135. The results are of particular interest for either hydrogen or direct methanol fuel cells where conductivity and membrane permeability are critical issues.
Michael A. Kertesz - One of the best experts on this subject based on the ideXlab platform.
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desulfurization and Desulfonation applications of sulfur controlled gene expression in bacteria
Applied Microbiology and Biotechnology, 2001Co-Authors: Michael A. Kertesz, C WietekAbstract:Inorganic sulfate is the preferred sulfur source for the growth of most microorganisms but, in its absence, many organosulfur compounds can be degraded microbially to provide sulfur. Desulfurization of dibenzothiophene (DBT) by Rhodococcus sp. and of aromatic sulfonates by Pseudomonas sp. has considerable biotechnological potential. Both these pathways require non-flavin-containing FMNH2-dependent monoxygenases (DszC/DszA and SsuD, respectively). FMNH2 is provided from the freely diffusible FMNH2 pool in the cell, and is replenished by specific NAD(P)H:FMN oxidoreductases (DszD and SsuE). Overexpression of the DszD FMN reductase in a heterologous system increases the efficiency of DBT desulfurization but is detrimental to cell growth at high levels. Expression of the sulfonatase that cleaves aromatic sulfonates (surfactants, dyes) is accompanied by synthesis of a thiol-specific antioxidant protein, which may protect the cell from superoxide radicals generated by autoxidation of the reduced flavin. Effective application of DBT desulfurization in the biodesulfurization of crude oil, and of arylsulfonate Desulfonation in bioremediation, may require optimization of both flavin reductase levels and antioxidant protection systems within the cell.
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riding the sulfur cycle metabolism of sulfonates and sulfate esters in gram negative bacteria
Fems Microbiology Reviews, 2000Co-Authors: Michael A. KerteszAbstract:Sulfonates and sulfate esters are widespread in nature, and make up over 95% of the sulfur content of most aerobic soils. Many microorganisms can use sulfonates and sulfate esters as a source of sulfur for growth, even when they are unable to metabolize the carbon skeleton of the compounds. In these organisms, expression of sulfatases and sulfonatases is repressed in the presence of sulfate, in a process mediated by the LysR-type regulator protein CysB, and the corresponding genes therefore constitute an extension of the cys regulon. Additional regulator proteins required for sulfonate Desulfonation have been identified in Escherichia coli (the Cbl protein) and Pseudomonas putida (the AsfR protein). Desulfonation of aromatic and aliphatic sulfonates as sulfur sources by aerobic bacteria is oxygen-dependent, carried out by the α-ketoglutarate-dependent taurine dioxygenase, or by one of several FMNH2-dependent monooxygenases. Desulfurization of condensed thiophenes is also FMNH2-dependent, both in the rhodococci and in two Gram-negative species. Bacterial utilization of aromatic sulfate esters is catalyzed by arylsulfatases, most of which are related to human lysosomal sulfatases and contain an active-site formylglycine group that is generated post-translationally. Sulfate-regulated alkylsulfatases, by contrast, are less well characterized. Our increasing knowledge of the sulfur-regulated metabolism of organosulfur compounds suggests applications in practical fields such as biodesulfurization, bioremediation, and optimization of crop sulfur nutrition.
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anaerobic Desulfonation of 4 tolylsulfonate and 2 4 sulfophenyl butyrate by a clostridium sp
Applied and Environmental Microbiology, 1996Co-Authors: Karin Denger, Michael A. Kertesz, Esther H Vock, Roberto Schon, Andreas Magli, Alasdair M CookAbstract:Alkyl- and arylsulfonates were tested as sole added sources of sulfur for the growth of enrichment cultures under strictly anaerobic denitrifying or fermentative conditions. Cultures that utilized taurine, ethylsulfonate, the dyestuffs orange II and acid red I, tolylsulfonate, 2-(4-sulfophenyl)butyrate (SPB), a dialkyltetralinesulfonate, and 1-(4-sulfophenyl)octane were readily obtained. We chose to work with the simple aromatic compounds and isolated a fermentative bacterium, strain EV4, which utilized SPB as the sole added source of sulfur in glucose-mineral medium. The organism was identified as a Clostridium sp. related to Clostridium beijerinckii. Clostridium sp. strain EV4 utilized seven of seven tested arylsulfonates quantitatively. The growth yield was about 3 kg of protein per mol of sulfur, whether sulfonate or sulfate was utilized. A major product specific to each sulfonate could be observed. Although no product was identified, the existence of anaerobic Desulfonation has been established.
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Desulfonation of aliphatic sulfonates by pseudomonas aeruginosa pao
Fems Microbiology Letters, 1996Co-Authors: Michael A. KerteszAbstract:Pseudomonas aeruginosa PAO1 used a broad range of alkanesulfonic acids as sole sulfur source for growth, with molar growth yields of 2.2 to 2.9 kg protein per mol sulfur. 4-Phenylbutane-1-sulfonate was desulfonated in vivo to yield 4-pheny 1-1-butyric acid quantitatively as the sole product, suggesting that the Desulfonation mechanism is the same as when alkanesulfonates serve as a carbon source for growth. This contrasts with aromatic sulfonate utilization in other organisms, where different Desulfonation reactions are used to provide carbon and sulfur. Desulfonation of alkanesulfonates to provide sulfur was repressed by sulfate or thiocyanate, and derepressed in their absence. The alkanesulfonatase system is hence controlled as part of the sulfate starvation-induced stimulon.
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Desulfonation of linear alkylbenzenesulfonate surfactants and related compounds by bacteria
Applied and Environmental Microbiology, 1994Co-Authors: Michael A. Kertesz, Pius Kolbener, Hermann Stockinger, Stefan Beil, Alasdair M CookAbstract:Pseudomonas putida S-313 (= DSM 6884) grew in sulfate-free medium when the sole sulfur source supplied was one of several arylsulfonates involved in the synthesis, application, or biodegradation of linear alkyl-benzenesulfonate (LAS) surfactants. 2-(4-Sulfophenyl)butyric acid, 4-n-butyl-1-methyl-6-sulfotetralin, and 4-toluenesulfonic acid were each completely utilized during growth, as were the model LAS 1-(4-sulfophenyl) octane and the arylsulfonate dyestuff Orange II. The product in each case was the corresponding phenol, which was identified by gas chromatography-mass spectrometry or 1H nuclear magnetic resonance. Stoichiometric conversion of 4-toluenesulfonic acid to 4-cresol was observed. The molar growth yields observed were 2.4 to 2.8 kg of protein per mol of S, which were comparable to the yield for sulfate. Commercial LAS disappeared from growth medium inoculated with strain S-313, but negligible growth occurred; digestion of cells in alkali led to recovery of the LAS mixture, which seemingly sorbed to the cells. However, mixed culture L6 was readily obtained from batch enrichment cultures containing commercial LAS as a sole sulfur source and an inoculum from domestic sewage. Culture L6 desulfonated components of the LAS surfactant to the corresponding phenols, which were identified by gas chromatography-mass spectrometry. Compounds with shorter alkyl chains were desulfonated preferentially, as were the centrally substituted isomers. In the presence of 200 μM sulfate, culture L6 grew well and LAS disappeared, although this was due purely to sorption, as shown by digestion of the cells in alkali. Thus, under sulfate-limited conditions, LAS can be desulfonated directly.