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Sample records for acidic degradation products

  1. Amino Acid Degradations Produced by Lipid Oxidation Products.

    PubMed

    Hidalgo, Francisco J; Zamora, Rosario

    2016-06-10

    Differently to amino acid degradations produced by carbohydrate-derived reactive carbonyls, amino acid degradations produced by lipid oxidation products are lesser known in spite of being lipid oxidation a major source of reactive carbonyls in food. This article analyzes the conversion of amino acids into Strecker aldehydes, α-keto acids, and amines produced by lipid-derived free radicals and carbonyl compounds, as well as the role of lipid oxidation products on the reactions suffered by these compounds: the formation of Strecker aldehydes and other aldehydes from α-keto acids; the formation of Strecker aldehydes and olefins from amines; the formation of shorter aldehydes from Strecker aldehydes; and the addition reactions suffered by the olefins produced from the amines. The relationships among all these reactions and the effect of reaction conditions on them are discussed. This knowledge should contribute to better control food processing in order to favor the formation of desirable beneficial compounds and to inhibit the production of compounds with deleterious properties. PMID:25748518

  2. Investigation of sorbic acid volatile degradation products in pharmaceutical formulations using static headspace gas chromatography.

    PubMed

    Yarramraju, Sitaramaraju; Akurathi, Vamsidhar; Wolfs, Kris; Van Schepdael, Ann; Hoogmartens, Jos; Adams, Erwin

    2007-06-28

    An analytical method that allows simultaneous analysis of sorbic acid and its degradation products was developed using static headspace gas chromatography (HS-GC). AT-Aquawax-DA, the capillary column used, showed good selectivity and separation towards sorbic acid and its degradation products. Sorbic acid degradation was investigated in both acidic and aqueous media at room and elevated temperatures. In total 12 sorbic acid degradation products were found, 8 of which could be characterized. The method was investigated for its accuracy towards estimation of degradation products. Using the HS-GC method different batches of pharmaceutical preparations such as cold cream, cetomacrogol cream and vaseline were investigated for sorbic acid degradation products which were estimated by applying the standard addition method. Acetaldehyde was found to be the major degradation product. The other identified degradation products were: acetone; 2-methylfuran; crotonaldehyde; alfa-angelicalactone; 2-acetyl, 5-methylfuran; toluene and 2,5-dimethylfuran. Both mass spectrometeric (MS) and flame ionization detection (FID) were used. The qualitative investigation was done on HS-GC-MS and the quantitative work on HS-GC-FID. PMID:17306494

  3. Production and degradation of oxalic acid by brown rot fungi

    SciTech Connect

    Espejo, E.; Agosin, E. )

    1991-07-01

    Our results show that all of the brown rot fungi tested produce oxalic acid in liquid as well as in semisolid cultures. Gloeophyllum trabeum, which accumulates the lowest amount of oxalic acid during decay of pine holocellulose, showed the highest polysaccharide-depolymerizing activity. Semisolid cultures inoculated with this fungus rapidly converted {sup 14}C-labeled oxalic acid to CO{sub 2} during cellulose depolymerization. The other brown rot fungi also oxidized {sup 14}C-labeled oxalic acid, although less rapidly. In contrast, semisolid cultures inoculated with the white rot fungus Coriolus versicolor did not significantly catabolize the acid and did not depolymerize the holocellulose during decay. Semisolid cultures of G. trabeum amended with desferrioxamine, a specific iron-chelating agent, were unable to lower the degree of polymerization of cellulose or to oxidize {sup 14}C-labeled oxalic acid to the extent or at the rate that control cultures did. These results suggest that both iron and oxalic acid are involved in cellulose depolymerization by brown rot fungi.

  4. Production and Degradation of Oxalic Acid by Brown Rot Fungi

    PubMed Central

    Espejo, Eduardo; Agosin, Eduardo

    1991-01-01

    Our results show that all of the brown rot fungi tested produce oxalic acid in liquid as well as in semisolid cultures. Gloeophyllum trabeum, which accumulates the lowest amount of oxalic acid during decay of pine holocellulose, showed the highest polysaccharide-depolymerizing activity. Semisolid cultures inoculated with this fungus rapidly converted 14C-labeled oxalic acid to CO2 during cellulose depolymerization. The other brown rot fungi also oxidized 14C-labeled oxalic acid, although less rapidly. In contrast, semisolid cultures inoculated with the white rot fungus Coriolus versicolor did not significantly catabolize the acid and did not depolymerize the holocellulose during decay. Semisolid cultures of G. trabeum amended with desferrioxamine, a specific iron-chelating agent, were unable to lower the degree of polymerization of cellulose or to oxidize 14C-labeled oxalic acid to the extent or at the rate that control cultures did. These results suggest that both iron and oxalic acid are involved in cellulose depolymerization by brown rot fungi. PMID:16348522

  5. Acid-catalyzed hydrolysis of BMS-582664: degradation product identification and mechanism elucidation.

    PubMed

    Zhao, Fang; Derbin, George; Miller, Scott; Badawy, Sherif; Hussain, Munir

    2012-09-01

    BMS-582664 is an investigational drug intended for cancer treatment through oral administration. The preformulation studies revealed two unexpected degradation products under acidic conditions by reversed-phase high-performance liquid chromatography with ultraviolet detection. Additional liquid chromatography-mass spectrometry results suggested that these were cleavage (hydrolysis) products of a diaryl ether. To further understand the degradation mechanism, the reaction was carried out in (18) O-labeled water. The (18) O was found to be incorporated in only one of the two hydrolysis products. The results suggest that the corresponding α carbon in the heterocycle was unusually eletrophilic in acidic conditions probably because of the protonation of the neighboring nitrogen. This led to the selective attack by water and the consequent hydrolysis products. The study provides a new example of hydrolytic degradation of pharmaceutical compounds, and the reaction center is an aromatic heterocyclic carbon with an aryloxy substitution. PMID:22189636

  6. Retrospective analysis for the identification of 4-aminocarminic acid photo-degradation products in beverages.

    PubMed

    Gosetti, Fabio; Chiuminatto, Ugo; Mastroianni, Rita; Mazzucco, Eleonora; Manfredi, Marcello; Marengo, Emilio

    2015-01-01

    This article deals with the identification of the photo-degradation products of 4-aminocarminic acid potentially present in commercial beverages. Sixteen beverages of different composition but all containing the E120 dye were previously analysed by ultra-high-performance liquid chromatography (UHPLC) coupled with quadrupole-time of flight mass spectrometry to identify the common degradation products of the E120 dye. Since it is plausible to find unauthorised 4-aminocarminic acid in beverages which report generic E120 dye on the label, retrospective analysis was employed here not only to search for the possible presence of 4-aminocarminic acid but also to investigate the potential formation of photo-degradation products derived from this compound. For this purpose, a statistical approach based on Student's t-test was used to compare the degraded beverages containing 4-aminocarminic acid with all the others. Five degradation products were identified and their structures were elucidated on the basis of the high-accuracy and high-resolution of mass and mass/mass spectra. The toxicity of the degradation products was evaluated through the Ames Salmonella/microsome mutagenicity assay. No evidence of mutagenicity was obtained for the beverages subjected or not to irradiation, whereas a toxic effect of the 4-aminocarminic acid standard solution already at 100.0 µg l(-1) was found. This leads, once again, to the conclusion that the toxicity study must be carried out on the beverages in order to take into account of all the possible masking/protection interactions among the ingredients. PMID:25562586

  7. Effect of Boric Acid on Volatile Products of Thermooxidative Degradation of Epoxy Polymers

    NASA Astrophysics Data System (ADS)

    Nazarenko, O. B.; Bukhareva, P. B.; Melnikova, T. V.; Visakh, P. M.

    2016-01-01

    The polymeric materials are characterized by high flammability. The use of flame retardants in order to reduce the flammability of polymers can lead to the formation of toxic gaseous products under fire conditions. In this work we studied the effect of boric acid on the volatile products of thermooxidative degradation of epoxy polymers. The comparative investigations were carried out on the samples of the unfilled epoxy resin and epoxy resin filled with a boric acid at percentage 10 wt. %. The analysis of the volatile decomposition products and thermal stability of the samples under heating in an oxidizing medium was performed using a thermal mass-spectrometric analysis. It is found that the incorporation of boric acid into the polymer matrix increases the thermal stability of epoxy composites and leads to a reduction in the 2-2.7 times of toxic gaseous products

  8. Degradation of vanillic acid and production of guaiacol by microorganisms isolated from cork samples.

    PubMed

    Alvarez-Rodríguez, María Luisa; Belloch, Carmela; Villa, Mercedes; Uruburu, Federico; Larriba, Germán; Coque, Juan José R

    2003-03-14

    The presence of guaiacol in cork stoppers is responsible for some cases of cork taint causing unpleasant alterations to wine. We have performed a characterization of the cork-associated microbiota by isolating 55 different microorganisms: eight yeast, 14 filamentous fungi or molds, 13 actinomycetes and 20 non-filamentous bacteria. A screening for degradation of vanillic acid and guaiacol production showed that none of the filamentous fungi could achieve any of these processes. By contrast, five of the eight yeast strains isolated were able to degrade vanillic acid, although it was not converted to guaiacol. Guaiacol production was only detected in four bacterial strains: one isolate of Bacillus subtilis and three actinomycetes, Streptomyces sp. A3, Streptomyces sp. A5 and Streptomyces sp. A13, were able to accumulate this compound in both liquid media and cultures over cork. These results suggest that guaiacol-mediated cork taint should be attributed to the degradative action of vanillic acid by bacterial strains growing on cork.

  9. Identification and Characterization of Two New Degradation Products of Saikosaponin A under Acid Hydrolytic Conditions.

    PubMed

    Li, Jun; Xu, Qiang; Jiang, Hua

    2016-01-01

    Saikosaponin (SS) A is a compound with various pharmacological properties and is easily degraded into SS-B1 and SS-G under acid conditions. In the present work, two new degradation products of SS-A, formed under acid hydrolytic conditions, were detected and isolated using analytical and semi-preparative liquid chromatography technology; furthermore, their structures were characterized as hydroxy-saikosaponin A and SS-B2 by spectral analysis, which is not only essential in stability-indicating method development and validation, but also could be used as a worst case scenario to assess the analytical method performance of SS-A. Moreover, their structural transformation pathways are also proposed. PMID:27649123

  10. Degradation of Fructans and Production of Propionic Acid by Bacteroides thetaiotaomicron are Enhanced by the Shortage of Amino Acids.

    PubMed

    Adamberg, Signe; Tomson, Katrin; Vija, Heiki; Puurand, Marju; Kabanova, Natalja; Visnapuu, Triinu; Jõgi, Eerik; Alamäe, Tiina; Adamberg, Kaarel

    2014-01-01

    Bacteroides thetaiotaomicron is commonly found in the human colon and stabilizes its ecosystem by catabolism of various polysaccharides. A model of cross-talk between the metabolism of amino acids and fructans in B. thetaiotaomicron was proposed. The growth of B. thetaiotaomicron DSM 2079 in two defined media containing mineral salts and vitamins, and supplemented with either 20 or 2 amino acids, was studied in an isothermal microcalorimeter. The polyfructans inulin (from chicory) and levan (synthesized using levansucrase from Pseudomonas syringae), two fructooligosaccharide preparations with different composition, sucrose and fructose were tested as substrates. The calorimetric power-time curves were substrate specific and typically multiauxic. A surplus of amino acids reduced the consumption of longer oligosaccharides (degree of polymerization > 3). Bacterial growth was not detected either in the carbohydrate free medium containing amino acids or in the medium with inulin as a sole carbohydrate. In amino acid-restricted medium, fermentation leading to acetic acid formation was dominant at the beginning of growth (up to 24 h), followed by increased lactic acid production, and mainly propionic and succinic acids were produced at the end of fermentation. In the medium supplemented with 20 amino acids, the highest production of d-lactate (82 ± 33 mmol/gDW) occurred in parallel with extensive consumption (up to 17 mmol/gDW) of amino acids, especially Ser, Thr, and Asp. The production of Ala and Glu was observed at growth on all substrates, and the production was enhanced under amino acid deficiency. The study revealed the influence of amino acids on fructan metabolism in B. thetaiotaomicron and showed that defined growth media are invaluable in elucidating quantitative metabolic profiles of the bacteria. Levan was shown to act as an easily degradable substrate for B. thetaiotaomicron. The effect of levan on balancing or modifying colon microbiota will

  11. Degradation of Fructans and Production of Propionic Acid by Bacteroides thetaiotaomicron are Enhanced by the Shortage of Amino Acids

    PubMed Central

    Adamberg, Signe; Tomson, Katrin; Vija, Heiki; Puurand, Marju; Kabanova, Natalja; Visnapuu, Triinu; Jõgi, Eerik; Alamäe, Tiina; Adamberg, Kaarel

    2014-01-01

    Bacteroides thetaiotaomicron is commonly found in the human colon and stabilizes its ecosystem by catabolism of various polysaccharides. A model of cross-talk between the metabolism of amino acids and fructans in B. thetaiotaomicron was proposed. The growth of B. thetaiotaomicron DSM 2079 in two defined media containing mineral salts and vitamins, and supplemented with either 20 or 2 amino acids, was studied in an isothermal microcalorimeter. The polyfructans inulin (from chicory) and levan (synthesized using levansucrase from Pseudomonas syringae), two fructooligosaccharide preparations with different composition, sucrose and fructose were tested as substrates. The calorimetric power-time curves were substrate specific and typically multiauxic. A surplus of amino acids reduced the consumption of longer oligosaccharides (degree of polymerization > 3). Bacterial growth was not detected either in the carbohydrate free medium containing amino acids or in the medium with inulin as a sole carbohydrate. In amino acid-restricted medium, fermentation leading to acetic acid formation was dominant at the beginning of growth (up to 24 h), followed by increased lactic acid production, and mainly propionic and succinic acids were produced at the end of fermentation. In the medium supplemented with 20 amino acids, the highest production of d-lactate (82 ± 33 mmol/gDW) occurred in parallel with extensive consumption (up to 17 mmol/gDW) of amino acids, especially Ser, Thr, and Asp. The production of Ala and Glu was observed at growth on all substrates, and the production was enhanced under amino acid deficiency. The study revealed the influence of amino acids on fructan metabolism in B. thetaiotaomicron and showed that defined growth media are invaluable in elucidating quantitative metabolic profiles of the bacteria. Levan was shown to act as an easily degradable substrate for B. thetaiotaomicron. The effect of levan on balancing or modifying colon microbiota will

  12. Degradation of 2,4-dichlorophenoxyacetic acid by a halotolerant strain of Penicillium chrysogenum: antibiotic production.

    PubMed

    Ferreira-Guedes, Sumaya; Mendes, Benilde; Leitão, Ana Lúcia

    2012-01-01

    The extensive use of pesticides in agriculture has prompted intensive research on chemical and biological methods in order to protect contamination of water and soil resources. In this paper the degradation of the pesticide 2,4-dichlorophenoxyacetic acid by a Penicillium chrysogenum strain previously isolated from a salt mine was studied in batch cultures. Co-degradation of 2,4-dichlorophenoxyacetic acid with additives such as sugar and intermediates of pesticide metabolism was also investigated. Penicillium chrysogenum in solid medium was able to grow at concentrations up to 1000 mg/L of 2,4-dichlorophenoxyacetic acid (2,4-D) with sucrose. Meanwhile, supplementation of the solid medium with glucose and lactose led to fungal growth at concentrations up to 500 mg/L of herbicide. Batch cultures of 2,4-D at 100 mg/L were developed under aerobic conditions with the addition of glucose, lactose and sucrose, showing sucrose as the best additional carbon source. The 2,4-D removal was quantified by liquid chromatography. The fungus was able to use 2,4-D as the sole carbon and energy source under 0%, 2% and 5.9% NaCl. The greatest 2,4-D degradation efficiency was found using alpha-ketoglutarate and ascorbic acid as co-substrates under 2% NaCl at pH 7. Penicillin production was evaluated in submerged cultures by bioassay, and higher amounts of beta-lactam antibiotic were produced when the herbicide was alone. Taking into account the ability of P. chrysogenum CLONA2 to degrade aromatic compounds, this strain could be an interesting tool for 2,4-D herbicide remediation in saline environments. PMID:22629643

  13. Degradation of 2,4-dichlorophenoxyacetic acid by a halotolerant strain of Penicillium chrysogenum: antibiotic production.

    PubMed

    Ferreira-Guedes, Sumaya; Mendes, Benilde; Leitão, Ana Lúcia

    2012-01-01

    The extensive use of pesticides in agriculture has prompted intensive research on chemical and biological methods in order to protect contamination of water and soil resources. In this paper the degradation of the pesticide 2,4-dichlorophenoxyacetic acid by a Penicillium chrysogenum strain previously isolated from a salt mine was studied in batch cultures. Co-degradation of 2,4-dichlorophenoxyacetic acid with additives such as sugar and intermediates of pesticide metabolism was also investigated. Penicillium chrysogenum in solid medium was able to grow at concentrations up to 1000 mg/L of 2,4-dichlorophenoxyacetic acid (2,4-D) with sucrose. Meanwhile, supplementation of the solid medium with glucose and lactose led to fungal growth at concentrations up to 500 mg/L of herbicide. Batch cultures of 2,4-D at 100 mg/L were developed under aerobic conditions with the addition of glucose, lactose and sucrose, showing sucrose as the best additional carbon source. The 2,4-D removal was quantified by liquid chromatography. The fungus was able to use 2,4-D as the sole carbon and energy source under 0%, 2% and 5.9% NaCl. The greatest 2,4-D degradation efficiency was found using alpha-ketoglutarate and ascorbic acid as co-substrates under 2% NaCl at pH 7. Penicillin production was evaluated in submerged cultures by bioassay, and higher amounts of beta-lactam antibiotic were produced when the herbicide was alone. Taking into account the ability of P. chrysogenum CLONA2 to degrade aromatic compounds, this strain could be an interesting tool for 2,4-D herbicide remediation in saline environments.

  14. Solid supported in situ derivatization extraction of acidic degradation products of nerve agents from aqueous samples.

    PubMed

    Chinthakindi, Sridhar; Purohit, Ajay; Singh, Varoon; Tak, Vijay; Dubey, D K; Pardasani, Deepak

    2014-09-12

    This study deals with the solid supported in situ derivatization extraction of acidic degradation products of nerve agents present in aqueous samples. Target analytes were alkyl alkylphosphonic acids and alkylphosphonic acids, which are important environmental signatures of nerve agents. The method involved tert-butyldimethylchlorosilane mediated in situ silylation of analytes on commercially available diatomaceous solid phase extraction cartridges. Various parameters such as derivatizing reagent, its concentration, reaction time, temperature and eluting solvent were optimized. Recoveries of the analytes were determined by GC-MS which ranged from 60% to 86%. The limits of detection (LOD) and limit of quantification (LOQ) with selected analytes were achieved down to 78 and 213ngmL(-1) respectively, in selected ion monitoring mode. The successful applicability of method was also demonstrated on samples of biological origin such as plasma and to the samples received in 34th official proficiency test conducted by the Organization for Prohibition the of Chemical Weapons. PMID:25103280

  15. LC/MS/MS identification of some folic acid degradation products after E-beam irradiation

    NASA Astrophysics Data System (ADS)

    Araújo, M. M.; Marchioni, E.; Zhao, M.; Kuntz, F.; Di Pascoli, T.; Villavicencio, A. L. C. H.; Bergaentzle, M.

    2012-08-01

    Folates belong to the B vitamin group based on the parental compound folic acid (FA). They are involved in important biochemical processes like DNA synthesis and repair. FA is composed of a pteridine ring, p-aminobenzoic acid and glutamate moieties. The human metabolism is not able to synthesize folates and therefore obtain them from diet. FA, a synthetic vitamin, is used as a food fortificant because of its low price, relative stability and increased bioavailability compared to natural folate forms. FA is known to be a sensitive compound easily degradable in aqueous solution by ultraviolet and visible light towards various by-products. Irradiation is a process for preservation of foods that uses accelerated electrons, gamma rays or X-rays. Irradiation is proposed for the treatment of various food products, eliminating or reducing pathogens and insects, increasing the storage time and replacing chemical fumigants. This study concerns the identification of degradation products of FA after E-beam irradiation. FA aqueous solutions were irradiated with a Van de Graaff electrons beam accelerator (2 MeV, 100 μA current, 20 cm scan width, dose rate about 2 kGy/s). Applied doses were between 0 (control) and 10.0 kGy. Absorbed doses were monitored with FWT 60.00 radiochromic dosimeters.

  16. Detection of chlorodifluoroacetic acid in precipitation: A possible product of fluorocarbon degradation

    SciTech Connect

    Martin, J.W.; Franklin, J.; Hanson, M.L.; Solomon, K.R.; Mabury, S.A.; Ellis, D.A.; Scott, B.F.; Muri, D.C.G.

    2000-01-15

    Chlorodiffluoroacetic acid (CDFA) was detected in rain and snow samples from various regions of Canada. Routine quantitative analysis was performed using an in-situ derivatization technique that allowed for the determination of CDFA by GC-MS of the anilide derivative. Validation of environmental CDFA was provided by strong anionic exchange chromatography and detection by {sup 19}F NMR. CDFA concentrations ranges from <7.1 to 170 ng L{sup {minus}1} among all samples analyzed. Monthly volume-weighted CDFA concentrations ranged from <7.1 to 170 ng L{sup {minus}1} among all samples analyzed. Monthly volume-weighted CDFA concentrations in rain event samples showed a seasonal trend between June and November 1998, peaking in late summer and decreasing in the fall for Guelph and Toronto sites. Preliminary toxicity tests with the aquatic macrophytes Myriophyllum sibiricum and Myriophyllum spicatum suggest that CDFA does not represent a risk of acute toxicity to these aquatic macrophytes at current environmental concentrations. A degradation study suggests that CDFA is recalcitrant to biotic and abiotic degradation relative to dichloroacetic acid (DCA) and may accumulate in the aquatic environment. On the basis of existing experimental data, the authors postulate that CDFA is a degradation product of CFC-113 and, to a lesser extent, HCFC-142b. If CFC-113 is a source, its ozone depletion potential may be lower than previously assumed. Further work is required to identify alternative atmospheric and terrestrial sources of CDFA.

  17. Detection of methylglyoxal as a degradation product of DNA and nucleic acid components treated with strong acid.

    PubMed

    Chaplen, F W; Fahl, W E; Cameron, D C

    1996-05-01

    The 1,2-diaminobenzene derivation assay for methylglyoxal in biological systems involves the use of perchloric acid, both as a deproteinizing agent and to prevent the spontaneous formation of methylglyoxal from glycolytic pathway intermediates. However, while using a modification of the standard literature assay to measure methylglyoxal in Chinese hamster ovary cells, we found that oxidation of nucleic acids and related compounds by perchloric or trichloroacetic acid results in the formation of methylglyoxal. Compounds containing 2-deoxyribose gave higher levels of methylglyoxal than those containing ribose; purine nucleotides and deoxynucleotides gave more methylglyoxal than did the pyrimidines. Nucleic acids were the most susceptible to degradation, with 12-fold more methylglyoxal being formed from DNA than RNA. Oxidation of nucleic acids increased with higher temperatures and with decreasing nucleic acid fragment size. Another product of nucleic acid oxidation was 2,3-butanedione, the 1,2-diaminobenzene derivative of which is sometimes used as an internal standard during methylglyoxal measurement. Unless accounted for during the assay procedure, the generation of methylglyoxal and 2,3-butanedione due to the oxidation of nucleic acids may lead to substantial errors in the determination of methylglyoxal concentrations in biological systems.

  18. Study on degradation kinetics of 2-(2-hydroxypropanamido) benzoic acid in aqueous solutions and identification of its major degradation product by UHPLC/TOF-MS/MS.

    PubMed

    Zhang, Qili; Guan, Jiao; Rong, Rong; Zhao, Yunli; Yu, Zhiguo

    2015-08-10

    A RP-HPLC method was developed and validated for the degradation kinetic study of 2-(2-hydroxypropanamido) benzoic acid (HPABA), a promising anti-inflammatory drug, which would provide a basis for further studies on HPABA. The effects of pH, temperature, buffer concentration and ionic strength on the degradation kinetics of HPABA were discussed. Experimental parameters such as degradation rate constants (k), activation energy (Ea), acid and alkali catalytic constants (k(ac), k(al)), shelf life (t1/2) and temperature coefficient (Q10) were calculated. The results indicated that degradation kinetics of HPABA followed zero-order reaction kinetics; degradation rate constants (k) of HPABA at different pH values demonstrated that HPABA was more stable in neutral and near-neutral conditions; the function of temperature on k obeyed the Arrhenius equation (r = 0.9933) and HPABA was more stable at lower temperature; with the increase of ionic strength and buffer concentration, the stability of HPABA was decreased. The major unknown degradation product of HPABA was identified by UHPLC/TOF-MS/MS with positive electrospray ionization. Results demonstrated that the hydrolysis product was the primary degradation product of HPABA and it was deduced as anthranilic acid.

  19. Degradation Kinetics and Mechanism of a β-Lactam Antibiotic Intermediate, 6-Aminopenicillanic Acid, in a New Integrated Production Process.

    PubMed

    Su, Min; Sun, Hua; Zhao, Yingying; Lu, Aidang; Cao, Xiaohui; Wang, Jingkang

    2016-01-01

    In an effort to promote sustainability and to reduce manufacturing costs, the traditional production process for 6-aminopenicillanic acid (6-APA) has been modified to include less processing units. The objectives of this study are to investigate the degradation kinetics of 6-APA, to propose a reasonable degradation mechanism, and to optimize the manufacturing conditions within this new process. A series of degradation kinetic studies were conducted in the presence of impurities, as well as at various chemical and physical conditions. The concentrations of 6-APA were determined by high-performance liquid chromatography. An Arrhenius-type kinetic model was established to give a more accurate prediction on the degradation rates of 6-APA. A hydrolysis degradation mechanism is shown to be the major pathway for 6-APA. The degradation mechanisms and the kinetic models for 6-APA in the new system enable the design of a good manufacturing process with optimized parameters. PMID:26852849

  20. D-Galacturonic Acid: A Highly Reactive Compound in Nonenzymatic Browning. 2. Formation of Amino-Specific Degradation Products.

    PubMed

    Wegener, Steffen; Bornik, Maria-Anna; Kroh, Lothar W

    2015-07-22

    Thermal treatment of aqueous solutions of D-galacturonic acid and L-alanine at pH 3, 5, and 8 led to rapid and more intensive nonenzymatic browning reactions compared to similar solutions of other uronic acids and to Maillard reactions of reducing sugars. The hemiacetal ring structures of uronic acids had a high impact on browning behavior and reaction pathways. Besides reductic acid (1,2-dihydroxy-2-cyclopenten-1-one), 4,5-dihydroxy-2-cyclopenten-1-one (DHCP), furan-2-carboxaldehyde, and norfuraneol (4-hydroxy-5-methyl-3-(2H)-furanone) could be detected as typical products of nonenzymatic uronic acid browning reactions. 2-(2-Formyl-1H-pyrrole-1-yl)propanoic acid (FPA) and 1-(1-carboxyethyl)-3-hydroxypyridin-1-ium (HPA) were identified as specific reaction products of uronic acids with amine participation like l-alanine. In contrast, the structurally related D-galacturonic acid methyl ester showed less browning activity and degradation under equal reaction conditions. Pectin-specific degradation products such as 5-formyl-2-furanoic acid and 2-furanoic acid were found but could not be verified for d-galacturonic acid monomers alone. PMID:26111613

  1. D-Galacturonic Acid: A Highly Reactive Compound in Nonenzymatic Browning. 2. Formation of Amino-Specific Degradation Products.

    PubMed

    Wegener, Steffen; Bornik, Maria-Anna; Kroh, Lothar W

    2015-07-22

    Thermal treatment of aqueous solutions of D-galacturonic acid and L-alanine at pH 3, 5, and 8 led to rapid and more intensive nonenzymatic browning reactions compared to similar solutions of other uronic acids and to Maillard reactions of reducing sugars. The hemiacetal ring structures of uronic acids had a high impact on browning behavior and reaction pathways. Besides reductic acid (1,2-dihydroxy-2-cyclopenten-1-one), 4,5-dihydroxy-2-cyclopenten-1-one (DHCP), furan-2-carboxaldehyde, and norfuraneol (4-hydroxy-5-methyl-3-(2H)-furanone) could be detected as typical products of nonenzymatic uronic acid browning reactions. 2-(2-Formyl-1H-pyrrole-1-yl)propanoic acid (FPA) and 1-(1-carboxyethyl)-3-hydroxypyridin-1-ium (HPA) were identified as specific reaction products of uronic acids with amine participation like l-alanine. In contrast, the structurally related D-galacturonic acid methyl ester showed less browning activity and degradation under equal reaction conditions. Pectin-specific degradation products such as 5-formyl-2-furanoic acid and 2-furanoic acid were found but could not be verified for d-galacturonic acid monomers alone.

  2. In vitro cytotoxic and genotoxic effects of diphenylarsinic acid, a degradation product of chemical warfare agents.

    PubMed

    Ochi, Takafumi; Suzuki, Toshihide; Isono, Hideo; Kaise, Toshikazu

    2004-10-01

    Diphenylarsinic acid [DPAs(V)], a degradation product of diphenylcyanoarsine or diphenylchloroarsine, both of which were developed as chemical warfare agents, was investigated in terms of its capacity to induce cytotoxic effects, numerical and structural changes of chromosomes, and abnormalities of centrosome integrity and spindle organizations in conjunction with the effects of glutathione (GSH) depletion. DPAs(V) had toxic effects on cultured human hepatocarcinoma HepG2 cells at concentrations more than 0.5 mM. Depletion of GSH reduced the toxic effects of DPAs(V) as well as dimethylarsinic acid [DMAs(V)] toxicity, while toxicity by arsenite [iAs(III)] was enhanced. Exogenously added sulfhydryl (SH) compounds, such as dimercapropropane sulfonate (DMPS), GSH, and dithiothreitol (DTT), enhanced the toxic effects of DPAs(V) while they suppressed iAs(III) toxicity. DPAs(V) caused an increase in the mitotic index, and also structural and numerical changes in chromosomes in V79 Chinese hamster cells. Abnormality of centrosome integrity in mitotic V79 cells and multipolar spindles was also induced by DPAs(V) in a time- and concentration-dependent manner. These results suggested that highly toxic chemicals were generated by the interaction of DPAs(V) with SH compounds. Moreover, enhancements of toxicity by a combination of DPAs(V) and SH compounds suggested a risk in the use of SH compounds as a remedy for intoxication by diphenylarsenic compounds. Investigations on the effects of SH compounds on animals intoxicated with DPAs(V) are warranted.

  3. Separation and detection of VX and its methylphosphonic acid degradation products on a microchip using indirect laser-induced fluorescence.

    PubMed

    Heleg-Shabtai, Vered; Gratziany, Natzach; Liron, Zvi

    2006-05-01

    The application of indirect LIF (IDLIF) technique for on-chip electrophoretic separation and detection of the nerve agent O-ethyl S-[2-(diisopropylamino)ethyl] methylphosphonothiolate (VX) and its major phosphonic degradation products, ethyl methylphosphonic acid (EMPA) and methylphosphonic acid (MPA) was demonstrated. Separation and detection of MPA degradation products of VX and the nerve agent isopropyl methylphosphonofluoridate (GB) are presented. The negatively charged dye eosin was found to be a good fluorescent marker for both the negatively charged phosphonic acids and the positively charged VX, and was chosen as the IDLIF visualization fluorescent dye. Separation and detection of VX, EMPA, and MPA in a simple-cross microchip were completed within less than a minute, and consumed only a 50 pL sample volume. A characteristic system peak that appeared in all IDLIF electropherograms served as an internal standard that increased the reliability of peak identification. The negative peak of both VX and the MPAs is in agreement with indirect detection theory and with previous reports in the literature. The LOD of VX and EMPA by IDLIF was 30 and 37 microM, respectively. Despite the fact that the detection sensitivity is relatively low, the rapid simultaneous on-chip analysis of both VX and its degradation products as well as the separation and detection of the MPA degradation products of both VX and GB, increases detection reliability and may present a choice when sensitivity is not critical compared with speed and simplicity of the assay. PMID:16703628

  4. Separation and detection of VX and its methylphosphonic acid degradation products on a microchip using indirect laser-induced fluorescence.

    PubMed

    Heleg-Shabtai, Vered; Gratziany, Natzach; Liron, Zvi

    2006-05-01

    The application of indirect LIF (IDLIF) technique for on-chip electrophoretic separation and detection of the nerve agent O-ethyl S-[2-(diisopropylamino)ethyl] methylphosphonothiolate (VX) and its major phosphonic degradation products, ethyl methylphosphonic acid (EMPA) and methylphosphonic acid (MPA) was demonstrated. Separation and detection of MPA degradation products of VX and the nerve agent isopropyl methylphosphonofluoridate (GB) are presented. The negatively charged dye eosin was found to be a good fluorescent marker for both the negatively charged phosphonic acids and the positively charged VX, and was chosen as the IDLIF visualization fluorescent dye. Separation and detection of VX, EMPA, and MPA in a simple-cross microchip were completed within less than a minute, and consumed only a 50 pL sample volume. A characteristic system peak that appeared in all IDLIF electropherograms served as an internal standard that increased the reliability of peak identification. The negative peak of both VX and the MPAs is in agreement with indirect detection theory and with previous reports in the literature. The LOD of VX and EMPA by IDLIF was 30 and 37 microM, respectively. Despite the fact that the detection sensitivity is relatively low, the rapid simultaneous on-chip analysis of both VX and its degradation products as well as the separation and detection of the MPA degradation products of both VX and GB, increases detection reliability and may present a choice when sensitivity is not critical compared with speed and simplicity of the assay.

  5. Role of degradation products of chlorogenic acid in the antioxidant activity of roasted coffee.

    PubMed

    Kamiyama, Masumi; Moon, Joon-Kwan; Jang, Hae Won; Shibamoto, Takayuki

    2015-02-25

    Antioxidant activities of brewed coffees prepared from six commercial brands ranged from 63.13 ± 1.01 to 96.80 ± 1.68% at the highest levels tested. Generally, the degree of antioxidant activity of the brewed coffee was inversely proportional to the total chlorogenic acid concentration. A sample obtained from the major chlorogenic acid, 5-caffeoylquinic acid (5-CQA), heated at 250 °C exhibited potent antioxidant activity (79.12 ± 2.49%) at the level of 10 μg/mL, whereas unheated 5-CQA showed only moderate antioxidant activity (44.41 ± 0.27%) at the level of 100 μg/mL. Heat produced relatively high levels of pyrocatechol (2,809.3 μg/g) and 2-methoxy-4-vinylphenol (46.4 μg/g) from 5-CQA, and their antioxidant activity levels were 76.57 ± 3.00 and 98.63 ± 0.01%, respectively. The results of the present study suggest that roasting degrades chlorogenic acids to form potent antioxidants and thus plays an important role in the preparation of high-antioxidant low-acid coffee. PMID:25658375

  6. The Fate and Transport of Glyphosate and its Degradation Product, Aminomethylphosphonic Acid (AMPA), in Water

    NASA Astrophysics Data System (ADS)

    Scribner, E.; Meyer, M. T.

    2006-05-01

    Since 2001, the U.S. Geological Survey (USGS) has investigated the fate and transport of glyphosate and its degradation product, aminomethylphosphonic acid (AMPA), in surface water, and more recently in tile-drain flow, soil, and wet deposition. According to U.S. Environmental Protection Agency sources, glyphosate is among the world's most widely used herbicides. In 2004, glyphosate usage estimates indicated that between 103 and 113 million pounds were applied annually to crops in the United States. The use of glyphosate over a wide geographic area suggests that this herbicide might be a potential concern for air, water, and soil quality as well as measured in high concentrations in streams; therefore, it is important to monitor its fate and transport in ground-water/surface-water systems. National, regional, and field-scale studies conducted by the USGS National Water-Quality Assessment and Toxic Substance Hydrology Programs have studied the fate and transport of glyphosate in overland flow, tile- drain flow, surface water, soil, and wet-deposition samples. The samples were analyzed for glyphosate and AMPA by using derivatization and online solid-phase extraction with liquid chromatography/mass spectrometry (LC/MS) and LC/MS/MS methods developed by the USGS Organic Geochemistry Research Laboratory in Lawrence, Kansas. During spring, summer, and fall 2002 runoff periods in 50 Midwestern streams, glyphosate was detected at or above the 0.10 micrograms per liter detection limit in 35, 41, and 31 percent of samples, respectively. AMPA was detected in 53, 82, and 75 percent of samples, respectively. Results of 128 samples from a field study showed that glyphosate was transported as a narrow high- concentration pulse during the first period of runoff after application and that the concentration of glyphosate in runoff was greater than the concentration of AMPA. In tile-drain flow, glyphosate and AMPA were transported in a broad low-concentration pulse during these same

  7. [Analysis of alkaline CuO degradation products of acid detergent fiber from tobacco leaves by using liquid chromatography].

    PubMed

    Hao, Weiqiang; Wang, Leijun; Wu, Shun; Yue, Bangyi; Chen, Qiang; Zhang, Peipei

    2015-07-01

    The acid detergent fiber (ADF) from tobacco leaves was obtained by treating the sample with petroleum ether-ethanol (6:4, v/v), 30 g/L sodium dodecylsulfate and 0.5 mol/L sulphuric acid containing 20 g/L hexadecyl trimethyl ammonium bromide successively. The ADF was degraded by the alkaline CuO oxidation procedure. In this work, six samples of ADF degradation products from tobacco leaves were prepared. The samples were analyzed by using gradient liquid chromatography (LC) where an Ultimate XB C18 column was used as stationary phase, with a mixture of methanol and water as mobile phase, at a column temperature of 35 °C and a flow rate of 0.8 mL/min. Dual wavelengths of 280 nm and 320 nm were chosen for the detection. It was found that there were four characteristic peaks for the ADF degradation products. By taking these peaks as research object, the optimum time for the degradation was found to be 5 h and the sample solution could be kept stable within 7 days. The established method may provide a new approach for the studies of the differences between lignin composition in different tobacco leaves and the relationship between lignin content and the smoking quality of tobacco leaves. PMID:26672209

  8. Enhanced degradation of five organophosphorus pesticides in skimmed milk by lactic acid bacteria and its potential relationship with phosphatase production.

    PubMed

    Zhang, Ying-Hua; Xu, Di; Liu, Jia-Qi; Zhao, Xin-Huai

    2014-12-01

    Skimmed milk spiked with five organophosphorus pesticides (OPPs), chlorpyrifos, diazinon, fenitrothion, malathion and methyl parathion, was fermented by ten lactic acid bacteria (LAB) and four strain combinations at 42°C for 24h. OPPs left in the samples at different times were extracted, purified, detected by gas chromatography and calculated for degradation rate constants, based on a first-order reaction model. OPPs degradation was enhanced by the inoculated LAB, resulting in 0.8-225.4% increase in the rate constants. Diazinon and methyl parathion were more stable whereas chlorpyrifos, fenitrothion and malathion were more labile. Lactobacillus brevis 1.0209 showed the strongest acceleration on OPPs degradation while strain combination could bring about a synergy between the strains of lower ability. Phosphatase production of the strains might be one of the key factors responsible for the enhanced OPPs degradation, as the detected phosphatase activities were positively correlated to the measured degradation rate constants of OPPs (r=0.636-0.970, P<0.05). PMID:24996321

  9. Enhanced degradation of five organophosphorus pesticides in skimmed milk by lactic acid bacteria and its potential relationship with phosphatase production.

    PubMed

    Zhang, Ying-Hua; Xu, Di; Liu, Jia-Qi; Zhao, Xin-Huai

    2014-12-01

    Skimmed milk spiked with five organophosphorus pesticides (OPPs), chlorpyrifos, diazinon, fenitrothion, malathion and methyl parathion, was fermented by ten lactic acid bacteria (LAB) and four strain combinations at 42°C for 24h. OPPs left in the samples at different times were extracted, purified, detected by gas chromatography and calculated for degradation rate constants, based on a first-order reaction model. OPPs degradation was enhanced by the inoculated LAB, resulting in 0.8-225.4% increase in the rate constants. Diazinon and methyl parathion were more stable whereas chlorpyrifos, fenitrothion and malathion were more labile. Lactobacillus brevis 1.0209 showed the strongest acceleration on OPPs degradation while strain combination could bring about a synergy between the strains of lower ability. Phosphatase production of the strains might be one of the key factors responsible for the enhanced OPPs degradation, as the detected phosphatase activities were positively correlated to the measured degradation rate constants of OPPs (r=0.636-0.970, P<0.05).

  10. Residual Host Cell Protein Promotes Polysorbate 20 Degradation in a Sulfatase Drug Product Leading to Free Fatty Acid Particles.

    PubMed

    Dixit, Nitin; Salamat-Miller, Nazila; Salinas, Paul A; Taylor, Katherine D; Basu, Sujit K

    2016-05-01

    This study investigated the root cause behind an observed free fatty acid particle formation and resulting Polysorbate 20 (PS20) loss for a sulfatase drug product upon long-term storage at 5 ± 3°C. Reversed- phase chromatography with mass spectrometric analysis as well as charged aerosol detection was used to characterize the peaks associated with the intact and degraded PS20. Additionally, a proteomics study was undertaken to identify the residual host cell proteins in the sulfatase drug substance. PS20 stability studies were conducted in the presence of sulfatase, a sulfatase inhibitor, putative phospholipase B-like 2, and mock drug substance produced using a null cell line vector under experimental conditions optimized for PS20 degradation. This study provides the first published evidence where the residual host cell protein present in the drug substance was identified and experimentally shown to catalyze the breakdown of PS20 in a protein formulation over time, resulting in free fatty acid particles and PS20 loss. This study demonstrates the importance of early detection of potential impurities in the protein drug substance that may contribute to polysorbate degradation to make a judicious selection of the surfactant and its optimized concentration for the final drug product. PMID:27032893

  11. PEGylated single-walled carbon nanotubes activate neutrophils to increase production of hypochlorous acid, the oxidant capable of degrading nanotubes

    SciTech Connect

    Vlasova, Irina I.; Vakhrusheva, Tatyana V.; Sokolov, Alexey V.; Kostevich, Valeria A.; Gusev, Alexandr A.; Gusev, Sergey A.; Melnikova, Viktoriya I.; Lobach, Anatolii S.

    2012-10-01

    Perspectives for the use of carbon nanotubes in biomedical applications depend largely on their ability to degrade in the body into products that can be easily cleared out. Carboxylated single-walled carbon nanotubes (c-SWCNTs) were shown to be degraded by oxidants generated by peroxidases in the presence of hydrogen peroxide. In the present study we demonstrated that conjugation of poly(ethylene glycol) (PEG) to c-SWCNTs does not interfere with their degradation by peroxidase/H{sub 2}O{sub 2} system or by hypochlorite. Comparison of different heme-containing proteins for their ability to degrade PEG-SWCNTs has led us to conclude that the myeloperoxidase (MPO) product hypochlorous acid (HOCl) is the major oxidant that may be responsible for biodegradation of PEG-SWCNTs in vivo. MPO is secreted mainly by neutrophils upon activation. We hypothesize that SWCNTs may enhance neutrophil activation and therefore stimulate their own biodegradation due to MPO-generated HOCl. PEG-SWCNTs at concentrations similar to those commonly used in in vivo studies were found to activate isolated human neutrophils to produce HOCl. Both PEG-SWCNTs and c-SWCNTs enhanced HOCl generation from isolated neutrophils upon serum-opsonized zymosan stimulation. Both types of nanotubes were also found to activate neutrophils in whole blood samples. Intraperitoneal injection of a low dose of PEG-SWCNTs into mice induced an increase in percentage of circulating neutrophils and activation of neutrophils and macrophages in the peritoneal cavity, suggesting the evolution of an inflammatory response. Activated neutrophils can produce high local concentrations of HOCl, thereby creating the conditions favorable for degradation of the nanotubes. -- Highlights: ► Myeloperoxidase (MPO) product hypochlorous acid is able to degrade CNTs. ► PEGylated SWCNTs stimulate isolated neutrophils to produce hypochlorous acid. ► SWCNTs are capable of activating neutrophils in blood samples. ► Activation of

  12. Excretion pathways and ruminal disappearance of glyphosate and its degradation product aminomethylphosphonic acid in dairy cows.

    PubMed

    von Soosten, D; Meyer, U; Hüther, L; Dänicke, S; Lahrssen-Wiederholt, M; Schafft, H; Spolders, M; Breves, G

    2016-07-01

    From 6 balance experiments with total collection of feces and urine, samples were obtained to investigate the excretion pathways of glyphosate (GLY) in lactating dairy cows. Each experiment lasted for 26d. The first 21d served for adaptation to the diet, and during the remaining 5d collection of total feces and urine was conducted. Dry matter intake and milk yield were recorded daily and milk and feed samples were taken during the sampling periods. In 2 of the 6 experiments, at the sampling period for feces and urine, duodenal contents were collected for 5d. Cows were equipped with cannulas at the dorsal sac of the rumen and the proximal duodenum. Duodenal contents were collected every 2h over 5 consecutive days. The daily duodenal dry matter flow was measured by using chromium oxide as a volume marker. All samples (feed, feces, urine, milk and duodenal contents were analyzed for GLY and aminomethylphosphonic acid (AMPA). Overall, across the 6 experiments (n=32) the range of GLY intake was 0.08 to 6.67mg/d. The main proportion (61±11%; ±SD) of consumed GLY was excreted with feces; whereas excretion by urine was 8±3% of GLY intake. Elimination via milk was negligible. The GLY concentrations above the limit of quantification were not detected in any of the milk samples. A potential ruminal degradation of GLY to AMPA was derived from daily duodenal GLY flow. The apparent ruminal disappearance of GLY intake was 36 and 6%. In conclusion, the results of the present study indicate that the gastrointestinal absorption of GLY is of minor importance and fecal excretion represents the major excretion pathway. A degradation of GLY to AMPA by rumen microbes or a possible retention in the body has to be taken into account.

  13. The Impact of Enzyme Characteristics on Corn Stover Fiber Degradation and Acid Production During Ensiled Storage

    NASA Astrophysics Data System (ADS)

    Ren, Haiyu; Richard, Tom L.; Moore, Kenneth J.

    Ensilage can be used to store lignocellulosic biomass before industrial bioprocessing. This study investigated the impacts of seven commerical enzyme mixtures derived from Aspergillus niger, Trichoderma reesei, and T. longibrachiatum. Treatments included three size grades of corn stover, two enzyme levels (1.67 and 5 IU/g dry matter based on hemicellulase), and various ratios of cellulase to hemicellulase (C ∶ H). The highest C ∶ H ratio tested, 2.38, derived from T. reesei, resulted in the most effective fermentation, with lactic acid as the dominant product. Enzymatic activity during storage may complement industrial pretreatment; creating synergies that could reduce total bioconversion costs.

  14. Aqueous thermal degradation of gallic acid

    NASA Astrophysics Data System (ADS)

    Snow Boles, Jennifer; Crerar, David A.; Grissom, Grady; Key, Tonalee C.

    1988-02-01

    Aqueous thermal degradation experiments show gallic acid, a naturally occurring aromatic carboxylic compound, decomposes rapidly at temperatures between 105° and 150°C, with an activation energy of 22.9 or 27.8 kcal/ mole, depending on pH of the starting solution. Pyrogallol is the primary product identified, indicating degradation via decarboxylation and a carbanion transition state. Relatively rapid degradation of vanillic, phthalic, ellagic and tannic acids has also been observed, suggesting that these and perhaps other aromatic acids could be short-lived in deep formation waters.

  15. Aqueous thermal degradation of gallic acid

    SciTech Connect

    Boles, J.S.; Crerar, D.A.; Grissom, G.; Key, T.C.

    1988-02-01

    Aqueous thermal degradation experiments show gallic acid, a naturally occurring aromatic carboxylic compound, decomposes rapidly at temperatures between 105/sup 0/ and 150/sup 0/C, with an activation energy of 22.9 or 27.8 kcal/mole, depending on pH of the starting solution. Pyrogallol is the primary product identified, indicating degradation via decarboxylation and a carbanion transition state. Relatively rapid degradation of vanillic, phthalic, ellagic and tannic acids has also been observed,suggesting that these and perhaps other aromatic acids could be short-lived in deep formation waters.

  16. Materials degradation caused by acid rain

    SciTech Connect

    Baboian, R.

    1986-01-01

    This book presents the papers given at a symposium on acid rain. Topics considered at the symposium included acidification, wet deposition, dry deposition, the corrosion of metals, corrosion products, the weathering of steel, environmental effects, automotive corrosion, effects on indoor surfaces, the degradation of organics, effects on wood surfaces, effects on plants, the acid rain degradation of nylon, the legal aspects of materials damage, the economic features of materials degradation, the economic assessment of acid damage to building materials, and the application of a theory for the economic assessment of corrosion damage.

  17. Validated stability-indicating spectrophotometric methods for the determination of cefixime trihydrate in the presence of its acid and alkali degradation products.

    PubMed

    Mostafa, Nadia M; Abdel-Fattah, Laila; Weshahy, Soheir A; Hassan, Nagiba Y; Boltia, Shereen A

    2015-01-01

    Five simple, accurate, precise, and economical spectrophotometric methods have been developed for the determination of cefixime trihydrate (CFX) in the presence of its acid and alkali degradation products without prior separation. In the first method, second derivative (2D) and first derivative (1D) spectrophotometry was applied to the absorption spectra of CFX and its acid (2D) or alkali (1D) degradation products by measuring the amplitude at 289 and 308 nm, respectively. The second method was a first derivative (1DD) ratio spectrophotometric method where the peak amplitudes were measured at 311 nm in presence of the acid degradation product, and 273 and 306 nm in presence of its alkali degradation product. The third method was ratio subtraction spectrophotometry where the drug is determined at 286 nm in laboratory-prepared mixtures of CFX and its acid or alkali degradation product. The fourth method was based on dual wavelength analysis; two wavelengths were selected at which the absorbances of one component were the same, so wavelengths 209 and 252 nm were used to determine CFX in presence of its acid degradation product and 310 and 321 nm in presence of its alkali degradation product. The fifth method was bivariate spectrophotometric calibration based on four linear regression equations obtained at the wavelengths 231 and 290 nm, and 231 and 285 nm for the binary mixture of CFX with either its acid or alkali degradation product, respectively. The developed methods were successfully applied to the analysis of CFX in laboratory-prepared mixtures and pharmaceutical formulations with good recoveries, and their validation was carried out following the International Conference on Harmonization guidelines. The results obtained were statistically compared with each other and showed no significant difference with respect to accuracy and precision.

  18. Cytokine regulation of human lung fibroblast hyaluronan (hyaluronic acid) production. Evidence for cytokine-regulated hyaluronan (hyaluronic acid) degradation and human lung fibroblast-derived hyaluronidase.

    PubMed Central

    Sampson, P M; Rochester, C L; Freundlich, B; Elias, J A

    1992-01-01

    We characterized the mechanisms by which recombinant (r) tumor necrosis factor (TNF), IFN-gamma, and IL-1, alone and in combination, regulate human lung fibroblast hyaluronic acid (HA) production. Each cytokine stimulated fibroblast HA production. The combination of rTNF and rIFN-gamma resulted in a synergistic increase in the production of high molecular weight HA. This was due to a synergistic increase in hyaluronate synthetase activity and a simultaneous decrease in HA degradation. In contrast, when rTNF and rIL-1 were combined, an additive increase in low molecular weight HA was noted. This was due to a synergistic increase in hyaluronate synthetase activity and a simultaneous increase in HA degradation. Human lung fibroblasts contained a hyaluronidase that, at pH 3.7, depolymerized high molecular weight HA to 10-40 kD end products of digestion. However, hyaluronidase activity did not correlate with fibroblast HA degradation. Instead, HA degradation correlated with fibroblast-HA binding, which was increased by rIL-1 plus rTNF and decreased by rIFN-gamma plus rTNF. Recombinant IL-1 and rTNF weakly stimulated and rIL-1 and rTNF in combination further augmented the levels of CD44 mRNA in lung fibroblasts. In contrast, rIFN-gamma did not significantly alter the levels of CD44 mRNA in unstimulated or rTNF stimulated cells. These studies demonstrate that rIL-1, rTNF, and rIFN-gamma have complex effects on biosynthesis and degradation which alter the quantity and molecular weight of the HA produced by lung fibroblasts. They also show that fibroblast HA degradation is mediated by a previously unrecognized lysosomal-type hyaluronidase whose function may be regulated by altering fibroblast-HA binding. Lastly, they suggest that the CD44 HA receptor may be involved in this process. Images PMID:1401082

  19. Hydrogen production using amino acids obtained by protein degradation in waste biomass by combined dark- and photo-fermentation.

    PubMed

    Cheng, Jun; Ding, Lingkan; Xia, Ao; Lin, Richen; Li, Yuyou; Zhou, Junhu; Cen, Kefa

    2015-03-01

    The biological hydrogen production from amino acids obtained by protein degradation was comprehensively investigated to increase heating value conversion efficiency. The five amino acids (i.e., alanine, serine, aspartic acid, arginine, and leucine) produced limited hydrogen (0.2-16.2 mL/g) but abundant soluble metabolic products (40.1-84.0 mM) during dark-fermentation. The carbon conversion efficiencies of alanine (85.3%) and serine (94.1%) during dark-fermentation were significantly higher than those of other amino acids. Residual dark-fermentation solutions treated with zeolite for NH4(+) removal were inoculated with photosynthetic bacteria to further produce hydrogen during photo-fermentation. The hydrogen yields of alanine and serine through combined dark- and photo-fermentation were 418.6 and 270.2 mL/g, respectively. The heating value conversion efficiency of alanine to hydrogen was 25.1%, which was higher than that of serine (21.2%).

  20. The novel acid degradation products of losartan: Isolation and characterization using Q-TOF, 2D-NMR and FTIR.

    PubMed

    Kumar Pandey, Avadhesh; Rapolu, Ravi; Raju, Ch Krishnam; Sasalamari, Gururaj; Kumar Goud, Sanath; Awasthi, Atul; Navalgund, Sameer G; Surendranath, Koduru V

    2016-02-20

    Forced degradation of losartan potassium in acidic condition resulted into three potential unknown impurities. These unknown degradation products marked as LD-I, LD-II and LD-III were analyzed using a new reverse-phase high performance liquid chromatography (HPLC), eluting at 3.63, 3.73 and 3.91 relative retention times with respect to losartan potassium (LOS) peak. All three were isolated from reaction mass using preparative HPLC and their structures were elucidated using LC-MS/MS, multidimensional NMR and FTIR spectroscopic techniques, as 5(2),11(2)-dibutyl-5(4),11(4)-dichloro-1(1)H,5(1)H,7(1)H,11(1)H-1(5,1),7(1,5)-ditetrazola-5,11(1,5)-diimidazola-2,8(1,2),3,9(1,4)-tetrabenzenacyclododecaphane,(Z)-5(2),11(2)-dibutyl-5(4),11(4)-dichloro-1(1)H,5(1)H,7(2)H,11(1)H-1(5,1),7(2,5)-ditetrazola-5,11(1,5)-diimidazola-2,8(1,2),3,9(1,4)-tetrabenzenacyclododecaphane, and 5(2),11(2)-dibutyl-5(4),11(4)-dichloro-1(2)H,5(1)H,7(2)H,11(1)H-1(5,2),7(2,5)-ditetrazola-5,11(1,5)-diimidazola-2,8(1,2),3,9(1,4)-tetrabenzenacyclododecaphane, respectively. To best of our knowledge, all three degradation products are novel impurities which are not discussed at any form of publication yet. PMID:26704631

  1. Advanced stability indicating chemometric methods for quantitation of amlodipine and atorvastatin in their quinary mixture with acidic degradation products

    NASA Astrophysics Data System (ADS)

    Darwish, Hany W.; Hassan, Said A.; Salem, Maissa Y.; El-Zeany, Badr A.

    2016-02-01

    Two advanced, accurate and precise chemometric methods are developed for the simultaneous determination of amlodipine besylate (AML) and atorvastatin calcium (ATV) in the presence of their acidic degradation products in tablet dosage forms. The first method was Partial Least Squares (PLS-1) and the second was Artificial Neural Networks (ANN). PLS was compared to ANN models with and without variable selection procedure (genetic algorithm (GA)). For proper analysis, a 5-factor 5-level experimental design was established resulting in 25 mixtures containing different ratios of the interfering species. Fifteen mixtures were used as calibration set and the other ten mixtures were used as validation set to validate the prediction ability of the suggested models. The proposed methods were successfully applied to the analysis of pharmaceutical tablets containing AML and ATV. The methods indicated the ability of the mentioned models to solve the highly overlapped spectra of the quinary mixture, yet using inexpensive and easy to handle instruments like the UV-VIS spectrophotometer.

  2. Thermal pretreatment of olive mill wastewater for efficient methane production: control of aromatic substances degradation by monitoring cyclohexane carboxylic acid.

    PubMed

    Pontoni, Ludovico; d'Antonio, Giuseppe; Esposito, Giovanni; Fabbricino, Massimiliano; Frunzo, Luigi; Pirozzi, Francesco

    2015-01-01

    Anaerobic digestion is investigated as a sustainable depurative strategy of olive oil mill wastewater (OOMW). The effect of thermal pretreatment on the anaerobic biodegradation of aromatic compounds present in (OMWW) was investigated. The anaerobic degradation of phenolic compounds, well known to be the main concern related to this kind of effluents, was monitored in batch anaerobic tests at a laboratory scale on samples pretreated at mild (80±1 °C), intermediate (90±1 °C) and high temperature (120±1 °C). The obtained results showed an increase of 34% in specific methane production (SMP) for OMWW treated at the lowest temperature and a decrease of 18% for treatment at the highest temperature. These results were related to the different decomposition pathways of the lignocellulosic compounds obtained in the tested conditions. The decomposition pathway was determined by measuring the concentrations of volatile organic acids, phenols, and chemical oxygen demand (COD) versus time. Cyclohexane carboxylic acid (CHCA) production was identified in all the tests with a maximum concentration of around 200 µmol L(-1) in accordance with the phenols degradation, suggesting that anaerobic digestion of aromatic compounds follows the benzoyl-CoA pathway. Accurate monitoring of this compound was proposed as the key element to control the process evolution. The total phenols (TP) and total COD removals were, with SMP, the highest (TP 62.7%-COD 63.2%) at 80 °C and lowest (TP 44.9%-COD 32.2%) at 120 °C. In all cases, thermal pretreatment was able to enhance the TP removal ability (up to 42% increase).

  3. Thermal pretreatment of olive mill wastewater for efficient methane production: control of aromatic substances degradation by monitoring cyclohexane carboxylic acid.

    PubMed

    Pontoni, Ludovico; d'Antonio, Giuseppe; Esposito, Giovanni; Fabbricino, Massimiliano; Frunzo, Luigi; Pirozzi, Francesco

    2015-01-01

    Anaerobic digestion is investigated as a sustainable depurative strategy of olive oil mill wastewater (OOMW). The effect of thermal pretreatment on the anaerobic biodegradation of aromatic compounds present in (OMWW) was investigated. The anaerobic degradation of phenolic compounds, well known to be the main concern related to this kind of effluents, was monitored in batch anaerobic tests at a laboratory scale on samples pretreated at mild (80±1 °C), intermediate (90±1 °C) and high temperature (120±1 °C). The obtained results showed an increase of 34% in specific methane production (SMP) for OMWW treated at the lowest temperature and a decrease of 18% for treatment at the highest temperature. These results were related to the different decomposition pathways of the lignocellulosic compounds obtained in the tested conditions. The decomposition pathway was determined by measuring the concentrations of volatile organic acids, phenols, and chemical oxygen demand (COD) versus time. Cyclohexane carboxylic acid (CHCA) production was identified in all the tests with a maximum concentration of around 200 µmol L(-1) in accordance with the phenols degradation, suggesting that anaerobic digestion of aromatic compounds follows the benzoyl-CoA pathway. Accurate monitoring of this compound was proposed as the key element to control the process evolution. The total phenols (TP) and total COD removals were, with SMP, the highest (TP 62.7%-COD 63.2%) at 80 °C and lowest (TP 44.9%-COD 32.2%) at 120 °C. In all cases, thermal pretreatment was able to enhance the TP removal ability (up to 42% increase). PMID:25624137

  4. Acid rain degradation of nylon

    SciTech Connect

    Kyllo, K.E.

    1984-01-01

    Acid rain, precipitation with a pH less than 5.6, is known to damage lakes, vegetation and buildings. Degradation of outdoor textiles by acid rain is strongly suspected but not well documented. This study reports the effects of sunlight, aqueous acid, heat and humidity (acid rain conditions) on spun delustered nylon 6,6 fabric. Untreated nylon and nylon treated with sulfuric acid of pH 2.0, 3.0, and 4.4 were exposed to light in an Atlas Xenon-arc fadeometer at 63/sup 0/C and 65% R.H. for up to 640 AATCC Fading Units. The untreated and acid treated nylon fabrics were also exposed to similar temperature and humidity condition without light. Nylon degradation was determined by changes in breaking strength, elongation, molecular weight, color, amino end group concentration (NH/sub 2/) and /sup 13/C NMR spectra. Physical damage was assessed using SEM.

  5. CHARACTERIZATION OF ARSENOSUGARS AND ASSOCIATED DEGRADATION PRODUCTS FOLLOWING AN AGGRESSIVE ACID/BASE EXTRACTION PROCEDURE

    EPA Science Inventory

    The speciation of arsenic in seafood products is important for the determination of an improved toxicity based relative source (water vs. diet) contribution estimate. The two major sources of arsenic are drinking water and seafood ingestion. Drinking water contains predominatel...

  6. Structural Characterization of the Degradation Products of a Minor Natural Sweet Diterpene Glycoside Rebaudioside M under Acidic Conditions

    PubMed Central

    Prakash, Indra; Chaturvedula, Venkata Sai Prakash; Markosyan, Avetik

    2014-01-01

    Degradation of rebaudioside M, a minor sweet component of Stevia rebaudiana Bertoni, under conditions that simulated extreme pH and temperature conditions has been studied. Thus, rebaudioside M was treated with 0.1 M phosphoric acid solution (pH 2.0) and 80 °C temperature for 24 h. Experimental results indicated that rebaudioside M under low pH and higher temperature yielded three minor degradation compounds, whose structural characterization was performed on the basis of 1D (1H-, 13C-) & 2D (COSY, HSQC, HMBC) NMR, HRMS, MS/MS spectral data as well as enzymatic and acid hydrolysis studies. PMID:24424316

  7. Characterization of degradation products of ivabradine by LC-HR-MS/MS: a typical case of exhibition of different degradation behaviour in HCl and H2SO4 acid hydrolysis.

    PubMed

    Patel, Prinesh N; Borkar, Roshan M; Kalariya, Pradipbhai D; Gangwal, Rahul P; Sangamwar, Abhay T; Samanthula, Gananadhamu; Ragampeta, Srinivas

    2015-02-01

    A validated stability-indicating HPLC method was established, and comprehensive stress testing of ivabradine, a cardiotonic drug, was carried out as per ICH guidelines. Ivabradine was subjected to acidic, basic and neutral hydrolysis, oxidation, photolysis and thermal stress conditions, and the resulting degradation products were investigated by LC-PDA and LC-HR-MS/MS. The drug was found to degrade in acid and base hydrolysis. An efficient and selective stability assay method was developed on Phenomenex Luna C18 (250 × 4.6 mm, 5.0 µm) column using ammonium formate (10 mM, pH 3.0) and acetonitrile as mobile phase at 30 °C in gradient elution mode. The flow rate was 0.7 ml/min and detection wavelength was 286 nm. A total of five degradation products (I-1 to I-5) were identified and characterized by LC-HR-MS/MS in combination with accurate mass measurements. The drug exhibited different degradation behaviour in HCl and H2SO4 hydrolysis conditions. It is a unique example where two of the five degradation products in HCl hydrolysis were absent in H2SO4 acid hydrolysis. The present study provides guidance to revise the stress test for the determination of inherent stability of drugs containing lactam moiety under hydrolytic conditions. Most probable mechanisms for the formation of degradation products have been proposed on the basis of a comparison of the fragmentation pattern of the drug and its degradation products. In silico toxicity revealed that the degradation products (I-2 to I-5) were found to be severe irritants in case of ocular irritancy. The analytical assay method was validated with respect to specificity, linearity, range, precision, accuracy and robustness.

  8. Degradation of emerging contaminants from water under natural sunlight: The effect of season, pH, humic acids and nitrate and identification of photodegradation by-products.

    PubMed

    Koumaki, Elena; Mamais, Daniel; Noutsopoulos, Constantinos; Nika, Maria-Christina; Bletsou, Anna A; Thomaidis, Nikolaos S; Eftaxias, Alexander; Stratogianni, Georgia

    2015-11-01

    Both photodegradation and hydrolysis of non-steroidal anti-inflammatory drugs (NSAIDs) and endocrine disrupting chemicals (EDCs) were investigated in order to evaluate their photochemical fate in aquatic environment and to assess the effect of season and specific characteristics of water (pH, humic acids and nitrate concentration) on the removal of target EDCs and NSAIDs through photodegradation. An additional objective was the identification of the photodegradation by-products of specific NSAIDs and their dependence on irradiation time. Selected compounds' transformation was investigated under natural sunlight radiation while control experiments were conducted in the dark. As expected, most of compounds' degradation rate decreased with decreasing light intensity between two different experimental periods. Most of the tested compounds exhibited different rates of degradation during direct and indirect photolysis. The degradation rate of the selected compounds increased in the presence of NO3(-) and the photodegradation rate was higher for some compounds in alkaline than in acidic solution. The effect of humic acids' presence in the water depends on the absorbance spectrum of the compound and the produced photosensitizers. More specifically, humic acids act as inner filter toward most of the selected NSAIDs and as photosensitizers toward most of the EDCs. The results of the irradiation experiments in the presence of both humic acids and NO3(-), indicate that the direct photolysis is much more efficient than indirect photochemical processes. Finally, several degradation by-products of ketoprofen and diclofenac were identified in the samples, exposed to sunlight. The dependence of these by-products on radiation time is also demonstrated.

  9. Fourier Transform Infrared Spectroscopy and Multivariate Analysis for Online Monitoring of Dibutyl Phosphate Degradation Product in Tributyl Phosphate /n-Dodecane/Nitric Acid Solvent

    SciTech Connect

    Levitskaia, Tatiana G.; Peterson, James M.; Campbell, Emily L.; Casella, Amanda J.; Peterman, Dean; Bryan, Samuel A.

    2013-11-05

    In liquid-liquid extraction separation processes, accumulation of organic solvent degradation products is detrimental to the process robustness and frequent solvent analysis is warranted. Our research explores feasibility of online monitoring of the organic solvents relevant to used nuclear fuel reprocessing. This paper describes the first phase of developing a system for monitoring the tributyl phosphate (TBP)/n-dodecane solvent commonly used to separate used nuclear fuel. In this investigation, the effect of extraction of nitric acid from aqueous solutions of variable concentrations on the quantification of TBP and its major degradation product dibutyl phosphoric acid (HDBP) was assessed. Fourier Transform Infrared Spectroscopy (FTIR) spectroscopy was used to discriminate between HDBP and TBP in the nitric acid-containing TBP/n-dodecane solvent. Multivariate analysis of the spectral data facilitated the development of regression models for HDBP and TBP quantification in real time, enabling online implementation of the monitoring system. The predictive regression models were validated using TBP/n-dodecane solvent samples subjected to the high dose external gamma irradiation. The predictive models were translated to flow conditions using a hollow fiber FTIR probe installed in a centrifugal contactor extraction apparatus demonstrating the applicability of the FTIR technique coupled with multivariate analysis for the online monitoring of the organic solvent degradation products.

  10. Fourier Transform Infrared Spectroscopy and Multivariate Analysis for Online Monitoring of Dibutyl Phosphate Degradation Product in Tributyl Phosphate/n-Dodecane/Nitric Acid Solvent

    SciTech Connect

    Tatiana G. Levitskaia; James M. Peterson; Emily L. Campbell; Amanda J. Casella; Dean R. Peterman; Samuel A. Bryan

    2013-12-01

    In liquid–liquid extraction separation processes, accumulation of organic solvent degradation products is detrimental to the process robustness, and frequent solvent analysis is warranted. Our research explores the feasibility of online monitoring of the organic solvents relevant to used nuclear fuel reprocessing. This paper describes the first phase of developing a system for monitoring the tributyl phosphate (TBP)/n-dodecane solvent commonly used to separate used nuclear fuel. In this investigation, the effect of extraction of nitric acid from aqueous solutions of variable concentrations on the quantification of TBP and its major degradation product dibutylphosphoric acid (HDBP) was assessed. Fourier transform infrared (FTIR) spectroscopy was used to discriminate between HDBP and TBP in the nitric acid-containing TBP/n-dodecane solvent. Multivariate analysis of the spectral data facilitated the development of regression models for HDBP and TBP quantification in real time, enabling online implementation of the monitoring system. The predictive regression models were validated using TBP/n-dodecane solvent samples subjected to high-dose external ?-irradiation. The predictive models were translated to flow conditions using a hollow fiber FTIR probe installed in a centrifugal contactor extraction apparatus, demonstrating the applicability of the FTIR technique coupled with multivariate analysis for the online monitoring of the organic solvent degradation products.

  11. Structural elucidation of gemifloxacin mesylate degradation product.

    PubMed

    Paim, Clésio Soldateli; Führ, Fernanda; Martins, Magda Targa; Gnoatto, Simone; Bajerski, Lisiane; Garcia, Cássia Virginia; Steppe, Martin; Schapoval, Elfrides Eva Scherman

    2016-03-01

    Gemifloxacin mesylate (GFM), chemically (R,S)-7-[(4Z)-3-(aminomethyl)-4-(methoxyimino)-1-pyrrolidinyl]-1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-1,8-naphthyridine-3-carboxylic acid methanesulfonate, is a synthetic broad-spectrum antibacterial agent. Although many papers have been published in the literature describing the stability of fluorquinolones, little is known about the degradation products of GFM. Forced degradation studies of GFM were performed using radiation (UV-A), acid (1 mol L(-1) HCl) and alkaline conditions (0.2 mol L(-1) NaOH). The main degradation product, formed under alkaline conditions, was isolated using semi-preparative LC and structurally elucidated by nuclear magnetic resonance (proton - (1) H; carbon - (13) C; correlate spectroscopy - COSY; heteronuclear single quantum coherence - HSQC; heteronuclear multiple-bond correlation - HMBC; spectroscopy - infrared, atomic emission and mass spectrometry techniques). The degradation product isolated was characterized as sodium 7-amino-1-pyrrolidinyl-1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-1,8-naphthyridine-3-carboxylate, which was formed by loss of the 3-(aminomethyl)-4-(methoxyimino)-1-pyrrolidinyl ring and formation of the sodium carboxylate. The structural characterization of the degradation product was very important to understand the degradation mechanism of the GFM under alkaline conditions. In addition, the results highlight the importance of appropriate protection against hydrolysis and UV radiation during the drug-development process, storage, handling and quality control.

  12. Formic and Acetic Acids in Degradation Products of Plant Volatiles Elicit Olfactory and Behavioral Responses from an Insect Vector.

    PubMed

    George, Justin; Robbins, Paul S; Alessandro, Rocco T; Stelinski, Lukasz L; Lapointe, Stephen L

    2016-05-01

    Volatile phytochemicals play a role in orientation by phytophagous insects. We studied antennal and behavioral responses of the Asian citrus psyllid, Diaphorina citri, vector of the citrus greening disease pathogen. Little or no response to citrus leaf volatiles was detected by electroantennography. Glass cartridges prepared with β-ocimene or citral produced no response initially but became stimulatory after several days. Both compounds degraded completely in air to a number of smaller molecules. Two peaks elicited large antennal responses and were identified as acetic and formic acids. Probing by D. citri of a wax substrate containing odorants was significantly increased by a blend of formic and acetic acids compared with either compound separately or blends containing β-ocimene and/or citral. Response surface modeling based on a 4-component mixture design and a 2-component mixture-amount design predicted an optimal probing response on wax substrate containing a blend of formic and acetic acids. Our study suggests that formic and acetic acids play a role in host selection by D. citri and perhaps by phytophagous insects in general even when parent compounds from which they are derived are not active. These results have implications for the investigation of arthropod olfaction and may lead to elaboration of attract-and-kill formulations to reduce nontarget effects of chemical control in agriculture. PMID:26857741

  13. Production of polyhydroxyhexadecanoic acid by using waste biomass of Sphingobacterium sp. ATM generated after degradation of textile dye Direct Red 5B.

    PubMed

    Tamboli, Dhawal P; Kagalkar, Anuradha N; Jadhav, Mital U; Jadhav, Jyoti P; Govindwar, Sanjay P

    2010-04-01

    The degradation of textile effluent using microorganisms has been studied extensively, but disposal of generated biomass after dye degradation is a serious problem. The isolated Sphingobacterium sp. ATM was found to decolorize dye Direct Red 5B (DR5B) and simultaneously it produced polyhydroxyhexadecanoic acid (PHD). The organism decolorized DR5B at 500mgl(-1) concentration within 24h of dye addition and gave optimum production of PHD. The medium contains carbon source as a molasses which was found to be more significant within all carbon sources used. The Nuclear Magnetic Resonance spectroscopy (NMR), Fourier Transform Infrared spectroscopy (FTIR) and Gas Chromatography-Mass Spectroscopy (GC-MS) characterization of polyhydroxyalkanoates obtained revealed the compound as a polyhydroxyhexadecanoic acid. The activity of PHA synthase was found more at 24h after dye addition. The enzymes responsible for dye degradation include veratrol oxidase, laccase, DCIP (2,6-dichlorophenol-indophenol) reductase, riboflavin reductase and azo reductase was found to be induced during decolorization process. The FTIR analysis of samples before and after decolorization of dye confirmed the biotransformation of DR5B. The GC-MS analysis of product obtained led to the identification of two metabolites after biotransformation of dye as p-amino benzenesulfonic acid and naphthalene-1-ol.

  14. Production of polyhydroxyhexadecanoic acid by using waste biomass of Sphingobacterium sp. ATM generated after degradation of textile dye Direct Red 5B.

    PubMed

    Tamboli, Dhawal P; Kagalkar, Anuradha N; Jadhav, Mital U; Jadhav, Jyoti P; Govindwar, Sanjay P

    2010-04-01

    The degradation of textile effluent using microorganisms has been studied extensively, but disposal of generated biomass after dye degradation is a serious problem. The isolated Sphingobacterium sp. ATM was found to decolorize dye Direct Red 5B (DR5B) and simultaneously it produced polyhydroxyhexadecanoic acid (PHD). The organism decolorized DR5B at 500mgl(-1) concentration within 24h of dye addition and gave optimum production of PHD. The medium contains carbon source as a molasses which was found to be more significant within all carbon sources used. The Nuclear Magnetic Resonance spectroscopy (NMR), Fourier Transform Infrared spectroscopy (FTIR) and Gas Chromatography-Mass Spectroscopy (GC-MS) characterization of polyhydroxyalkanoates obtained revealed the compound as a polyhydroxyhexadecanoic acid. The activity of PHA synthase was found more at 24h after dye addition. The enzymes responsible for dye degradation include veratrol oxidase, laccase, DCIP (2,6-dichlorophenol-indophenol) reductase, riboflavin reductase and azo reductase was found to be induced during decolorization process. The FTIR analysis of samples before and after decolorization of dye confirmed the biotransformation of DR5B. The GC-MS analysis of product obtained led to the identification of two metabolites after biotransformation of dye as p-amino benzenesulfonic acid and naphthalene-1-ol. PMID:20031399

  15. Fatty Acid Structure and Degradation Analysis in Fingerprint Residues.

    PubMed

    Pleik, Stefanie; Spengler, Bernhard; Schäfer, Thomas; Urbach, Dieter; Luhn, Steven; Kirsch, Dieter

    2016-09-01

    GC-MS investigations were carried out to elucidate the aging behavior of unsaturated fatty acids in fingerprint residues and to identify their degradation products in aged samples. For this purpose, a new sample preparation technique for fingerprint residues was developed that allows producing N-methyl-N-trimethylsilyl-trifluoroacetamide (MSTFA) derivatives of the analyzed unsaturated fatty acids and their degradation products. MSTFA derivatization catalyzed by iodotrimethylsilane enables the reliable identification of aldehydes and oxoacids as characteristic MSTFA derivatives in GCMS. The obtained results elucidate the degradation pathway of unsaturated fatty acids. Our study of aged fingerprint residues reveals that decanal is the main degradation product of the observed unsaturated fatty acids. Furthermore, oxoacids with different chain lengths are detected as specific degradation products of the unsaturated fatty acids. The detection of the degradation products and their chain length is a simple and effective method to determine the double bond position in unsaturated compounds. We can show that the hexadecenoic and octadecenoic acids found in fingerprint residues are not the pervasive fatty acids Δ9-hexadecenoic (palmitoleic acid) and Δ9-octadecenoic (oleic acid) acid but Δ6-hexadecenoic acid (sapienic acid) and Δ8-octadecenoic acid. The present study focuses on the structure identification of human sebum-specific unsaturated fatty acids in fingerprint residues based on the identification of their degradation products. These results are discussed for further investigations and method developments for age determination of fingerprints, which is still a tremendous challenge because of several factors affecting the aging behavior of individual compounds in fingerprints. Graphical Abstract ᅟ.

  16. Fatty Acid Structure and Degradation Analysis in Fingerprint Residues.

    PubMed

    Pleik, Stefanie; Spengler, Bernhard; Schäfer, Thomas; Urbach, Dieter; Luhn, Steven; Kirsch, Dieter

    2016-09-01

    GC-MS investigations were carried out to elucidate the aging behavior of unsaturated fatty acids in fingerprint residues and to identify their degradation products in aged samples. For this purpose, a new sample preparation technique for fingerprint residues was developed that allows producing N-methyl-N-trimethylsilyl-trifluoroacetamide (MSTFA) derivatives of the analyzed unsaturated fatty acids and their degradation products. MSTFA derivatization catalyzed by iodotrimethylsilane enables the reliable identification of aldehydes and oxoacids as characteristic MSTFA derivatives in GCMS. The obtained results elucidate the degradation pathway of unsaturated fatty acids. Our study of aged fingerprint residues reveals that decanal is the main degradation product of the observed unsaturated fatty acids. Furthermore, oxoacids with different chain lengths are detected as specific degradation products of the unsaturated fatty acids. The detection of the degradation products and their chain length is a simple and effective method to determine the double bond position in unsaturated compounds. We can show that the hexadecenoic and octadecenoic acids found in fingerprint residues are not the pervasive fatty acids Δ9-hexadecenoic (palmitoleic acid) and Δ9-octadecenoic (oleic acid) acid but Δ6-hexadecenoic acid (sapienic acid) and Δ8-octadecenoic acid. The present study focuses on the structure identification of human sebum-specific unsaturated fatty acids in fingerprint residues based on the identification of their degradation products. These results are discussed for further investigations and method developments for age determination of fingerprints, which is still a tremendous challenge because of several factors affecting the aging behavior of individual compounds in fingerprints. Graphical Abstract ᅟ. PMID:27324649

  17. Fatty Acid Structure and Degradation Analysis in Fingerprint Residues

    NASA Astrophysics Data System (ADS)

    Pleik, Stefanie; Spengler, Bernhard; Schäfer, Thomas; Urbach, Dieter; Luhn, Steven; Kirsch, Dieter

    2016-09-01

    GC-MS investigations were carried out to elucidate the aging behavior of unsaturated fatty acids in fingerprint residues and to identify their degradation products in aged samples. For this purpose, a new sample preparation technique for fingerprint residues was developed that allows producing N-methyl- N-trimethylsilyl-trifluoroacetamide (MSTFA) derivatives of the analyzed unsaturated fatty acids and their degradation products. MSTFA derivatization catalyzed by iodotrimethylsilane enables the reliable identification of aldehydes and oxoacids as characteristic MSTFA derivatives in GCMS. The obtained results elucidate the degradation pathway of unsaturated fatty acids. Our study of aged fingerprint residues reveals that decanal is the main degradation product of the observed unsaturated fatty acids. Furthermore, oxoacids with different chain lengths are detected as specific degradation products of the unsaturated fatty acids. The detection of the degradation products and their chain length is a simple and effective method to determine the double bond position in unsaturated compounds. We can show that the hexadecenoic and octadecenoic acids found in fingerprint residues are not the pervasive fatty acids Δ9-hexadecenoic (palmitoleic acid) and Δ9-octadecenoic (oleic acid) acid but Δ6-hexadecenoic acid (sapienic acid) and Δ8-octadecenoic acid. The present study focuses on the structure identification of human sebum-specific unsaturated fatty acids in fingerprint residues based on the identification of their degradation products. These results are discussed for further investigations and method developments for age determination of fingerprints, which is still a tremendous challenge because of several factors affecting the aging behavior of individual compounds in fingerprints.

  18. Analytical method for the quantitative determination of cyanuric acid as the degradation product of sodium dichloroisocyanurate in urine by liquid chromatography mass spectrometry.

    PubMed

    Patel, Katan; Jones, Kate

    2007-06-15

    A simple and selective analytical method for the quantitative determination of cyanuric acid, the degradation product of sodium dichloroisocyanurate (NaDCC), in human urine is reported herein. The sample preparation involved the use of diatomaceous earth extraction columns. Quantification was achieved by liquid chromatography mass spectrometry using negative ion electrospray with a cyano (CN) column. Between day relative standard deviation less than 10% (n=6) was obtained at the 5 mg L(-1) level. The assay was linear over the investigated range 0-20 mg L(-1) and the limit of detection (LOD) was confirmed to be 0.1 mg L(-1). The method was applied to monitoring levels of cyanuric acid in healthcare workers using disinfectants products containing NaDCC. PMID:17409034

  19. Degradation of benzoic acid and its derivatives in subcritical water.

    PubMed

    Lindquist, Edward; Yang, Yu

    2011-04-15

    In this research, the stability of benzoic acid and three of its derivatives (anthranilic acid, salicylic acid, and syringic acid) under subcritical water conditions was investigated. The stability studies were carried out at temperatures ranging from 50 to 350°C with heating times of 10-630 min. The degradation of the benzoic acid derivatives increased with rising temperature and the acids became less stable with longer heating time. The three benzoic acid derivatives showed very mild degradation at 150°C. Severe degradation of benzoic acid derivatives was observed at 200°C while their complete degradation occurred at 250°C. However, benzoic acid remained stable at temperatures up to 300°C. The degradation products of benzoic acid and the three derivatives were identified and quantified by HPLC and confirmed by GC/MS. Anthranilic acid, salicylic acid, syringic acid, and benzoic acid in high-temperature water underwent decarboxylation to form aniline, phenol, syringol, and benzene, respectively.

  20. Stability-indicating methods for the analysis of ciprofloxacin in the presence of its acid induced degradation product: A comparative study

    NASA Astrophysics Data System (ADS)

    Attia, Khalid A. M.; Nassar, Mohammed W. I.; El-Zeiny, Mohamed B.; Serag, Ahmed

    2016-04-01

    Four rapid, simple, accurate and precise spectrophotometric methods were used for the determination of ciprofloxacin in the presence of its acidic degradation product. The methods under study are ratio derivative, ratio difference, mean centering and dual wavelength. All the methods were validated according to the ICH guidelines and the obtained accuracy, precision and repeatability were found to be within the acceptable limits. The selectivity of the proposed methods was tested using laboratory prepared mixtures and assessed by applying the standard addition technique. So, they can be used for the routine analysis of ciprofloxacin in quality-control laboratories.

  1. A study of tannic acid degradation by soil bacteria.

    PubMed

    Ilori, Matthew O; Adebusoye, Sunday A; Amund, Olukayode O; Oyetoran, Bodunde O

    2007-09-15

    A tannin-degrading strain of Bacillus sp. AB1 was isolated from a garden soil by enrichment. This organism was able to utilize 1% (w/v) tannic acid-a gallotannin at 30 degrees C and pH below 4.5 in a defined mineral medium where the acid was the sole source of carbon and energy under 96 h. Growth resulted in increase in OD concomitant with gradual decrease in pH of the culture medium. Analysis of the culture fluid by paper chromatography revealed glucose and gallic acid as major metabolites of tannic acid degradative pathway. Mineralization of tannic acid was informed when none of the metabolites was recovered after 96 h of incubation. The degradation potential of this isolate could be exploited for the production of tannase, improvement of livestock production and also detoxification of tannery effluents at extreme acidic conditions.

  2. Down-regulation of glutaminase C in human hepatocarcinoma cell by diphenylarsinic acid, a degradation product of chemical warfare agents.

    PubMed

    Kita, Kayoko; Suzuki, Toshihide; Ochi, Takafumi

    2007-05-01

    In a poisonous incident in Kamisu, Japan, it is understood that diphenylarsinic acid (DPAA) was a critical contaminant of ground water. Most patients showed dysfunction of the central nervous system. To understand the overall mechanism of DPAA toxicity and to gain some insight into the application of a remedy specific for intoxication, the molecular target must be clarified. As an approach, a high throughput analysis of cell proteins in cultured human hepatocarcinoma HpG2 exposed to DPAA was performed by two-dimensional electrophoresis (2-DE). Four proteins, which were up- and down-regulated by exposure of cultured HepG2 cells to DPAA, were identified. They were chaperonin containing TCP-1 (CCT) beta subunit, aldehyde dehydrogenase 1 (ALDH1), ribosomal protein P0 and glutaminase C (GAC). Of these, GAC was the only protein that was down-regulated by DPAA exposure, and cellular expression levels were reduced by DPAA in a concentration- and time-dependent manner. Decrease in cellular GAC levels was accompanied by decreased activity of the enzyme, phosphate-activated glutaminase (PAG). Decreased expression of GAC by DPAA was also observed in human cervical carcinoma HeLa and neuroblastoma SH-SY5Y cells. By contrast, no significant changes in GAC protein expression were observed when cells were incubated with arsenite [iAs (III)] and trivalent dimethylarsinous acid [DMA (III)]. In the central nervous system, GAC plays a role in the production of the neurotransmitter glutamic acid. Selective inhibition of GAC expression by DPAA may be a cause of dysfunction of glutamatergic neuronal transmission and the resultant neurological impairments. PMID:17321558

  3. Down-regulation of glutaminase C in human hepatocarcinoma cell by diphenylarsinic acid, a degradation product of chemical warfare agents

    SciTech Connect

    Kita, Kayoko . E-mail: kkayoko@pharm.teikyo-u.ac.jp; Suzuki, Toshihide; Ochi, Takafumi

    2007-05-01

    In a poisonous incident in Kamisu, Japan, it is understood that diphenylarsinic acid (DPAA) was a critical contaminant of ground water. Most patients showed dysfunction of the central nervous system. To understand the overall mechanism of DPAA toxicity and to gain some insight into the application of a remedy specific for intoxication, the molecular target must be clarified. As an approach, a high throughput analysis of cell proteins in cultured human hepatocarcinoma HpG2 exposed to DPAA was performed by two-dimensional electrophoresis (2-DE). Four proteins, which were up- and down-regulated by exposure of cultured HepG2 cells to DPAA, were identified. They were chaperonin containing TCP-1 (CCT) beta subunit, aldehyde dehydrogenase 1 (ALDH1), ribosomal protein P0 and glutaminase C (GAC). Of these, GAC was the only protein that was down-regulated by DPAA exposure, and cellular expression levels were reduced by DPAA in a concentration- and time-dependent manner. Decrease in cellular GAC levels was accompanied by decreased activity of the enzyme, phosphate-activated glutaminase (PAG). Decreased expression of GAC by DPAA was also observed in human cervical carcinoma HeLa and neuroblastoma SH-SY5Y cells. By contrast, no significant changes in GAC protein expression were observed when cells were incubated with arsenite [iAs (III)] and trivalent dimethylarsinous acid [DMA (III)]. In the central nervous system, GAC plays a role in the production of the neurotransmitter glutamic acid. Selective inhibition of GAC expression by DPAA may be a cause of dysfunction of glutamatergic neuronal transmission and the resultant neurological impairments.

  4. Screening of nerve agent degradation products by MALDI-TOFMS.

    PubMed

    Shu, You-Ren; Su, An-Kai; Liu, Ju-Tsung; Lin, Cheng-Huang

    2006-07-01

    A novel method for the rapid screening of degradation products derived from nerve agents by matrix-assisted laser desorption ionization time-of-flight mass spectrometry is described. Five standard products were selected as model compounds, including isopropyl methylphosphonic acid (IMPA), pinacolyl methylphosphonic acid (PMPA), ethyl methylphosphonic acid (EMPA), isobutyl methylphosphonic acid (i-BuMPA), and cyclohexyl methylphosphonic acid (CHMPA), which are degradation products of Sarin (GB), Soman (GD), VX, Russian VX (RVX), and GF, respectively. For comparison, CHCA (alpha-cyano-4-hydroxycinnamic acid) and DCCA (7-(diethylamino)coumarin-3-carboxylic acid) were used as the MALDI-matrix when the third harmonic generation (355 nm) of a Nd:YAG laser and a hydrogen Raman laser (multifrequency laser) were used, respectively. The method permitted the five nerve agent degradation products to be screened rapidly and successfully, suggesting that it has the potential for use as a routine monitoring tool. PMID:16808484

  5. Screening of nerve agent degradation products by MALDI-TOFMS.

    PubMed

    Shu, You-Ren; Su, An-Kai; Liu, Ju-Tsung; Lin, Cheng-Huang

    2006-07-01

    A novel method for the rapid screening of degradation products derived from nerve agents by matrix-assisted laser desorption ionization time-of-flight mass spectrometry is described. Five standard products were selected as model compounds, including isopropyl methylphosphonic acid (IMPA), pinacolyl methylphosphonic acid (PMPA), ethyl methylphosphonic acid (EMPA), isobutyl methylphosphonic acid (i-BuMPA), and cyclohexyl methylphosphonic acid (CHMPA), which are degradation products of Sarin (GB), Soman (GD), VX, Russian VX (RVX), and GF, respectively. For comparison, CHCA (alpha-cyano-4-hydroxycinnamic acid) and DCCA (7-(diethylamino)coumarin-3-carboxylic acid) were used as the MALDI-matrix when the third harmonic generation (355 nm) of a Nd:YAG laser and a hydrogen Raman laser (multifrequency laser) were used, respectively. The method permitted the five nerve agent degradation products to be screened rapidly and successfully, suggesting that it has the potential for use as a routine monitoring tool.

  6. Solvent degradation products in nuclear fuel processing solvents

    SciTech Connect

    Shook, H.E. Jr.

    1988-06-01

    The Savannah River Plant uses a modified Purex process to recover enriched uranium and separate fission products. This process uses 7.5% tri-n-butyl phosphate (TBP) dissolved in normal paraffin hydrocarbons for the solvent extraction of a nitric acid solution containing the materials to be separated. Periodic problems in product decontamination result from solvent degradation. A study to improve process efficiency has identified certain solvent degradation products and suggested mitigation measures. Undecanoic acid, lauric acid, and tridecanoic acid were tentatively identified as diluent degradation products in recycle solvent. These long-chain organic acids affect phase separation and lead to low decontamination factors. Solid phase extraction (SPE) was used to concentrate the organic acids in solvent prior to analysis by high performance liquid chromatography (HPLC). SPE and HPLC methods were optimized in this work for analysis of decanoic acid, undecanoic acid, and lauric acid in solvent. Accelerated solvent degradation studies with 7.5% TBP in normal paraffin hydrocarbons showed that long-chain organic acids and long-chain alkyl butyl phosphoric acids are formed by reactions with nitric acid. Degradation of both tributyl phosphate and hydrocarbon can be minimized with purified normal paraffin replacing the standard grade presently used. 12 refs., 1 fig., 3 tabs.

  7. Materials degradation caused by acid rain

    SciTech Connect

    Baboian, R.

    1986-01-01

    Materials Degradation Caused by Acid Rain, based on a symposium sponsored by the American Chemical Society, presents a detailed analysis of the types of materials damages that may result from acid deposition, as well as techniques for evaluating the economic impact of these damages. The 29 chapters are organized into five sections. These sections include: Measurement and Monitoring of Atmospheric Deposition; Metallic Corrosion; Degradation of Organics; and Economic Effects.

  8. Exploring the ability of Sphingobacterium sp. ATM to degrade textile dye Direct Blue GLL, mixture of dyes and textile effluent and production of polyhydroxyhexadecanoic acid using waste biomass generated after dye degradation.

    PubMed

    Tamboli, Dhawal P; Kurade, Mayur B; Waghmode, Tatoba R; Joshi, Swati M; Govindwar, Sanjay P

    2010-10-15

    The degradation of textile effluent using microorganisms has been studied extensively, but disposal of generated biomass after dye degradation is a serious problem. Among all tested microorganisms, isolated Sphingobacterium sp. ATM effectively decolorized (100%) the dye Direct Blue GLL (DBGLL) and simultaneously it produced (64%) polyhydroxyhexadecanoic acid (PHD). The organism decolorized DBGLL at 300 mg l(-1) concentration within 24 h of dye addition and gave optimum production of PHD. The organism also decolorized three combinations of mixture of dyes. The organism decolorized textile effluent too when it was combined with medium. The organism produced a maximum of 66% and 61% PHD while decolorizing mixture of dyes and textile effluent respectively. Molasses was found to be more significant within all carbon sources used. The activity of polyhydroxyalkanoate (PHA) synthase was found to be higher after 24 h of addition of DBGLL. The enzymes responsible for dye degradation, viz. veratryl alcohol oxidase, laccase, DCIP (2,6-dichlorophenol-indophenol) reductase, riboflavin reductase, and azo reductase were found to be induced during decolorization process of DBGLL and mixture of dyes. There was significant reduction in chemical oxygen demand (COD) and biological oxygen demand (BOD). FTIR analysis of samples before and after decolorization of dye confirmed the biotransformation of DBGLL.

  9. Structural Insights into 2,2′-Azino-Bis(3-Ethylbenzothiazoline-6-Sulfonic Acid) (ABTS)-Mediated Degradation of Reactive Blue 21 by Engineered Cyathus bulleri Laccase and Characterization of Degradation Products

    PubMed Central

    Kenzom, T.; Srivastava, P.

    2014-01-01

    Advanced oxidation processes are currently used for the treatment of different reactive dyes which involve use of toxic catalysts. Peroxidases are reported to be effective on such dyes and require hydrogen peroxide and/or metal ions. Cyathus bulleri laccase, expressed in Pichia pastoris, catalyzes efficient degradation (78 to 85%) of reactive azo dyes (reactive black 5, reactive orange 16, and reactive red 198) in the presence of synthetic mediator ABTS [2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)]. This laccase was engineered to degrade effectively reactive blue 21 (RB21), a phthalocyanine dye reported to be decolorized only by peroxidases. The 816-bp segment (toward the C terminus) of the lcc gene was subjected to random mutagenesis and enzyme variants (Lcc35, Lcc61, and Lcc62) were selected based on increased ABTS oxidizing ability. Around 78 to 95% decolorization of RB21 was observed with the ABTS-supplemented Lcc variants in 30 min. Analysis of the degradation products by mass spectrometry indicated the formation of several low-molecular-weight compounds. Mapping the mutations on the modeled structure implicated residues both near and far from the T1 Cu site that affected the catalytic efficiency of the mutant enzymes on ABTS and, in turn, the rate of oxidation of RB21. Several inactive clones were also mapped. The importance of geometry as well as electronic changes on the reactivity of laccases was indicated. PMID:25261507

  10. Structural insights into 2,2'-azino-Bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS)-mediated degradation of reactive blue 21 by engineered Cyathus bulleri Laccase and characterization of degradation products.

    PubMed

    Kenzom, T; Srivastava, P; Mishra, S

    2014-12-01

    Advanced oxidation processes are currently used for the treatment of different reactive dyes which involve use of toxic catalysts. Peroxidases are reported to be effective on such dyes and require hydrogen peroxide and/or metal ions. Cyathus bulleri laccase, expressed in Pichia pastoris, catalyzes efficient degradation (78 to 85%) of reactive azo dyes (reactive black 5, reactive orange 16, and reactive red 198) in the presence of synthetic mediator ABTS [2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)]. This laccase was engineered to degrade effectively reactive blue 21 (RB21), a phthalocyanine dye reported to be decolorized only by peroxidases. The 816-bp segment (toward the C terminus) of the lcc gene was subjected to random mutagenesis and enzyme variants (Lcc35, Lcc61, and Lcc62) were selected based on increased ABTS oxidizing ability. Around 78 to 95% decolorization of RB21 was observed with the ABTS-supplemented Lcc variants in 30 min. Analysis of the degradation products by mass spectrometry indicated the formation of several low-molecular-weight compounds. Mapping the mutations on the modeled structure implicated residues both near and far from the T1 Cu site that affected the catalytic efficiency of the mutant enzymes on ABTS and, in turn, the rate of oxidation of RB21. Several inactive clones were also mapped. The importance of geometry as well as electronic changes on the reactivity of laccases was indicated.

  11. Structural insights into 2,2'-azino-Bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS)-mediated degradation of reactive blue 21 by engineered Cyathus bulleri Laccase and characterization of degradation products.

    PubMed

    Kenzom, T; Srivastava, P; Mishra, S

    2014-12-01

    Advanced oxidation processes are currently used for the treatment of different reactive dyes which involve use of toxic catalysts. Peroxidases are reported to be effective on such dyes and require hydrogen peroxide and/or metal ions. Cyathus bulleri laccase, expressed in Pichia pastoris, catalyzes efficient degradation (78 to 85%) of reactive azo dyes (reactive black 5, reactive orange 16, and reactive red 198) in the presence of synthetic mediator ABTS [2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)]. This laccase was engineered to degrade effectively reactive blue 21 (RB21), a phthalocyanine dye reported to be decolorized only by peroxidases. The 816-bp segment (toward the C terminus) of the lcc gene was subjected to random mutagenesis and enzyme variants (Lcc35, Lcc61, and Lcc62) were selected based on increased ABTS oxidizing ability. Around 78 to 95% decolorization of RB21 was observed with the ABTS-supplemented Lcc variants in 30 min. Analysis of the degradation products by mass spectrometry indicated the formation of several low-molecular-weight compounds. Mapping the mutations on the modeled structure implicated residues both near and far from the T1 Cu site that affected the catalytic efficiency of the mutant enzymes on ABTS and, in turn, the rate of oxidation of RB21. Several inactive clones were also mapped. The importance of geometry as well as electronic changes on the reactivity of laccases was indicated. PMID:25261507

  12. Exploring the ability of Sphingobacterium sp. ATM to degrade textile dye Direct Blue GLL, mixture of dyes and textile effluent and production of polyhydroxyhexadecanoic acid using waste biomass generated after dye degradation.

    PubMed

    Tamboli, Dhawal P; Kurade, Mayur B; Waghmode, Tatoba R; Joshi, Swati M; Govindwar, Sanjay P

    2010-10-15

    The degradation of textile effluent using microorganisms has been studied extensively, but disposal of generated biomass after dye degradation is a serious problem. Among all tested microorganisms, isolated Sphingobacterium sp. ATM effectively decolorized (100%) the dye Direct Blue GLL (DBGLL) and simultaneously it produced (64%) polyhydroxyhexadecanoic acid (PHD). The organism decolorized DBGLL at 300 mg l(-1) concentration within 24 h of dye addition and gave optimum production of PHD. The organism also decolorized three combinations of mixture of dyes. The organism decolorized textile effluent too when it was combined with medium. The organism produced a maximum of 66% and 61% PHD while decolorizing mixture of dyes and textile effluent respectively. Molasses was found to be more significant within all carbon sources used. The activity of polyhydroxyalkanoate (PHA) synthase was found to be higher after 24 h of addition of DBGLL. The enzymes responsible for dye degradation, viz. veratryl alcohol oxidase, laccase, DCIP (2,6-dichlorophenol-indophenol) reductase, riboflavin reductase, and azo reductase were found to be induced during decolorization process of DBGLL and mixture of dyes. There was significant reduction in chemical oxygen demand (COD) and biological oxygen demand (BOD). FTIR analysis of samples before and after decolorization of dye confirmed the biotransformation of DBGLL. PMID:20591565

  13. Concentrations of Glyphosate, Its Degradation Product, Aminomethylphosphonic Acid, and Glufosinate in Ground- and Surface-Water, Rainfall, and Soil Samples Collected in the United States, 2001-06

    USGS Publications Warehouse

    Scribner, Elisabeth A.; Battaglin, William A.; Gilliom, Robert J.; Meyer, Michael T.

    2007-01-01

    The U.S. Geological Survey conducted a number of studies from 2001 through 2006 to investigate and document the occurrence, fate, and transport of glyphosate, its degradation product, aminomethylphosphonic acid (AMPA), and glufosinate in 2,135 ground- and surface-water samples, 14 rainfall samples, and 193 soil samples. Analytical methods were developed to detect and measure glyphosate, AMPA, and glufosinate in water, rainfall, and soil. Results show that AMPA was detected more frequently and occurred at similar or higher concentrations than the parent compound, glyphosate, whereas glufosinate was seldom found in the environment. Glyphosate and AMPA were detected more frequently in surface water than in ground water. Trace levels of glyphosate and AMPA may persist in the soil from year to year. The methods and data described in this report are useful to researchers and regulators interested in the occurrence, fate, and transport of glyphosate and AMPA in the environment.

  14. Photolytic degradation of chlorophenols from industrial wastewaters by organic oxidants peroxy acetic acid, para nitro benzoic acid and methyl ethyl ketone peroxide: identification of reaction products.

    PubMed

    Sharma, Swati; Mukhopadhyay, Mausumi; Murthy, Zagabathuni Venkata Panchakshari

    2014-01-01

    In this investigation, chlorophenol (CP) containing industrial wastewater was remediated by ultraviolet irradiation in conjunction with organic oxidants, peroxy acetic acid (PAA); para nitro benzoic acid (PNBA); and methyl ethyl ketone peroxide (MEKP). CP mineralization was studied with regard to chemical oxygen demand (COD) and chloride ion release under identical test conditions. COD depletion to the extent of 81% by PAA, 66% by PNBA, and 67% by MEKP was noted along with an upwardly mobile trend of chloride ion release upon irradiation of samples at 254 nm. A 90-99% decrease in CP concentration (as per high pressure liquid chromatography (HPLC) analysis) was achieved with an additional 15.0 ml of organic oxidant in all cases. Gas chromatography high resolution mass spectroscopy (GC-HRMS) results also indicated the formation of such reaction products as are free from chlorine substitutions. This treatment also leads to total decolorization of the collected samples. PMID:24647192

  15. Ultra-high-performance liquid chromatography/tandem high-resolution mass spectrometry analysis of sixteen red beverages containing carminic acid: identification of degradation products by using principal component analysis/discriminant analysis.

    PubMed

    Gosetti, Fabio; Chiuminatto, Ugo; Mazzucco, Eleonora; Mastroianni, Rita; Marengo, Emilio

    2015-01-15

    The study investigates the sunlight photodegradation process of carminic acid, a natural red colourant used in beverages. For this purpose, both carminic acid aqueous standard solutions and sixteen different commercial beverages, ten containing carminic acid and six containing E120 dye, were subjected to photoirradiation. The results show different patterns of degradation, not only between the standard solutions and the beverages, but also from beverage to beverage. Due to the different beverage recipes, unpredictable reactions take place between the dye and the other ingredients. To identify the dye degradation products in a very complex scenario, a methodology was used, based on the combined use of principal component analysis with discriminant analysis and ultra-high-performance liquid chromatography coupled with tandem high resolution mass spectrometry. The methodology is unaffected by beverage composition and allows the degradation products of carminic acid dye to be identified for each beverage. PMID:25149011

  16. Ultra-high-performance liquid chromatography/tandem high-resolution mass spectrometry analysis of sixteen red beverages containing carminic acid: identification of degradation products by using principal component analysis/discriminant analysis.

    PubMed

    Gosetti, Fabio; Chiuminatto, Ugo; Mazzucco, Eleonora; Mastroianni, Rita; Marengo, Emilio

    2015-01-15

    The study investigates the sunlight photodegradation process of carminic acid, a natural red colourant used in beverages. For this purpose, both carminic acid aqueous standard solutions and sixteen different commercial beverages, ten containing carminic acid and six containing E120 dye, were subjected to photoirradiation. The results show different patterns of degradation, not only between the standard solutions and the beverages, but also from beverage to beverage. Due to the different beverage recipes, unpredictable reactions take place between the dye and the other ingredients. To identify the dye degradation products in a very complex scenario, a methodology was used, based on the combined use of principal component analysis with discriminant analysis and ultra-high-performance liquid chromatography coupled with tandem high resolution mass spectrometry. The methodology is unaffected by beverage composition and allows the degradation products of carminic acid dye to be identified for each beverage.

  17. Acid rain and drinking water degradation.

    PubMed

    Middleton, P; Rhodes, S L

    1984-03-01

    Acid deposition-induced drinking water degradation is discussed with respect to the geographical extent of and the potential for dealing with possibly adverse human health impacts. Qualitative evidence from the northeastern United States and Sweden strongly suggests the existence of a linkage between these two environmental concerns. It is argued that water treatment and reduction of acid rain as solutions to the problem of water toxicity need closer evaluation. More research into the causal link is warranted since the addition of human health impacts to acid rain's environmental insults could have a significant bearing on discussions relating to acid rain controls.

  18. Evaluation of thermo sensitivity of curcumin and quantification of ferulic acid and vanillin as degradation products by a validated HPTLC method.

    PubMed

    Siddiqui, Nasir Ali

    2015-01-01

    Charismatic therapeutic potential of curcumin in biological research have triggered an interest to explore the thermal degradation pattern of curcumin, formation of ferulic acid and vanillin as degraded metabolites at different temperatures in methanol and corn oil. The results revealed 47% w/w loss of curcumin along with formation of 17% w/w vanillin and 9% w/w ferulic acid at boiling temperature of methanol while oil samples show 38.9% w/w loss of curcumin but not confirming the formation of ferulic acid and vanillin. Findings of this study revealed that formation of vanillin in methanol starts around 50°C and its concentration goes on increasing up to 70°C and then further degraded at boiling temperature of methanol. Formation of ferulic acid begins around 60°C and initially increases with rise of temperature and then decreases approaching boiling point of methanol. Vanillin as well as ferulic acid was absent in corn oil samples though degradation of curcumin was observed by reduction in peak area of curcumin. The present study was done by applying a validated high-performance thin-layer chromatography method. The method involved glass-backed HPTLC plates precoated with silica gel 60F254 as the stationary phase and toluene: ethyl acetate: methanol (8:1:1, v/v/v) as mobile phase.

  19. Oral administration of diphenylarsinic acid, a degradation product of chemical warfare agents, induces oxidative and nitrosative stress in cerebellar Purkinje cells.

    PubMed

    Kato, Koichi; Mizoi, Mutsumi; An, Yan; Nakano, Masayuki; Wanibuchi, Hideki; Endo, Ginji; Endo, Yoko; Hoshino, Mikio; Okada, Shoji; Yamanaka, Kenzo

    2007-11-10

    A new clinical syndrome with prominent cerebellar symptoms in patients living in Kamisu City, Ibaraki Prefecture, Japan, is described. Since the patients ingested drinking water containing diphenylarsinic acid (DPA), a stable degradation product of both diphenylcyanoarsine and diphenylchloroarsine, which were developed for use as chemical weapons and cause severe vomiting and sneezing, DPA was suspected of being responsible for the clinical syndrome. The purpose of the present study was to elucidate prominent cerebellar symptoms due to DPA. The aim of the study was to determine if single (15 mg/kg) or continuous (5 mg/kg/day for 5 weeks) oral administration of DPA to ICR-strain mice induced oxidative and/or nitrosative stress in their brain. Significantly positive staining with malondialdehyde (MDA) and 3-nitrotyrosine (3-NT) was observed in the cerebellar Purkinje cells by repeated administration (5 mg/kg/day) with DPA for 5 weeks that led to the cerebellar symptoms from a behavioral pharmacology standpoint and by single administration of DPA (15 mg/kg). Furthermore, it is possible that the production of 3-NT was not caused by peroxynitrite formation. The present results suggest the possibility that arsenic-associated novel active species may be a factor underlying the oxidative and nitrosative stress in Purkinje cells due to exposure to DPA, and that the damage may lead to the cerebellar symptoms.

  20. Degradation rates of glycerol polyesters at acidic and basic conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Polyesters prepared from glycerol with mixtures of adipic and citric acids were evaluated in the laboratory to estimate degradation rates over a range of pH conditions. These renewable polymers provide a market for glycerol that is generated during biodiesel production. The polyesters were prepared...

  1. Acid-degradable polyurethane particles for protein-based vaccines

    PubMed Central

    Bachelder, Eric M.; Beaudette, Tristan T.; Broaders, Kyle E.; Paramonov, Sergey E.; Dashe, Jesse; Fréchet, Jean M. J.

    2009-01-01

    Acid-degradable particles containing a model protein antigen, ovalbumin, were prepared from a polyurethane with acetal moieties embedded throughout the polymer, and characterized by dynamic light scattering and transmission electron microscopy. The small molecule degradation by-product of the particles was synthesized and tested in vitro for toxicity indicating an LC50 of 12,500 μg/ml. A new liquid chromatography-mass spectrometry technique was developed to monitor the in vitro degradation of these particles. The degradation by-product inside RAW macrophages was at its highest level after 24 hours of culture and was efficiently exocytosed until it was no longer detectable after four days. When tested in vitro, these particles induced a substantial increase in the presentation of the immunodominant ovalbumin-derived peptide SIINFEKL in both macrophages and dendritic cells. In addition, vaccination with these particles generated a cytotoxic T-lymphocyte response that was superior to both free ovalbumin and particles made from an analogous but slower-degrading acid-labile polyurethane polymer. Overall, we present a fully degradable polymer system with non-toxic by-products, which may find use in various biomedical applications including protein-based vaccines. PMID:18710254

  2. Water and UV degradable lactic acid polymers

    DOEpatents

    Bonsignore, P.V.; Coleman, R.D.

    1996-10-08

    A water and UV light degradable copolymer is described made from monomers of lactic acid and a modifying monomer selected from the class consisting of ethylene glycol, propylene glycol, P-dioxanone, 1,5 dioxepan-2-one, 1,4-oxathialan-2-one, 1,4-dioxide and mixtures thereof. These copolymers are useful for waste disposal and agricultural purposes. Also disclosed is a water degradable blend of polylactic acid or modified polylactic acid and high molecular weight polyethylene oxide wherein the high molecular weight polyethylene oxide is present in the range of from about 2 by weight to about 50% by weight, suitable for films. A method of applying an active material selected from the class of seeds, seedlings, pesticides, herbicides, fertilizers and mixtures thereof to an agricultural site is also disclosed.

  3. Water and UV degradable lactic acid polymers

    DOEpatents

    Bonsignore, Patrick V.; Coleman, Robert D.

    1996-01-01

    A water and UV light degradable copolymer of monomers of lactic acid and a modifying monomer selected from the class consisting of ethylene glycol, propylene glycol, P-dioxanone, 1,5 dioxepan-2-one, 1,4-oxathialan-2-one, 1,4-dioxide and mixtures thereof. These copolymers are useful for waste disposal and agricultural purposes. Also disclosed is a water degradable blend of polylactic acid or modified polylactic acid and high molecular weight polyethylene oxide wherein the high molecular weight polyethylene oxide is present in the range of from about 2 by weight to about 50% by weight, suitable for films. A method of applying an active material selected from the class of seeds, seedlings, pesticides, herbicides, fertilizers and mixtures thereof to an agricultural site is also disclosed.

  4. Water and UV degradable lactic acid polymers

    DOEpatents

    Bonsignore, P.V.; Coleman, R.D.

    1994-11-01

    A water and UV light degradable copolymer of monomers of lactic acid and a modifying monomer were selected from the class consisting of ethylene and polyethylene glycols, propylene and polypropylene glycols, P-dioxanone, 1,5 dioxepan-2-one, 1,4 -oxathialan-2-one, 1,4-dioxide and mixtures. These copolymers are useful for waste disposal and agricultural purposes. Also disclosed is a water degradable blend of polylactic acid or modified polylactic acid and high molecular weight polyethylene oxide where the high molecular weight polyethylene oxide is present in the range of from about 2% by weight to about 50% by weight, suitable for films. A method of applying an active material selected from the class of seeds, seedlings, pesticides, herbicides, fertilizers and mixtures to an agricultural site is also disclosed.

  5. Water and UV degradable lactic acid polymers

    DOEpatents

    Bonsignore, Patrick V.; Coleman, Robert D.

    1994-01-01

    A water and UV light degradable copolymer of monomers of lactic acid and a modifying monomer selected from the class consisting of ethylene and polyethylene glycols, propylene and polypropylene glycols, P-dioxanone, 1,5 dioxepan-2-one, 1,4 -oxathialan-2-one, 1,4-dioxide and mixtures thereof. These copolymers are useful for waste disposal and agricultural purposes. Also disclosed is a water degradable blend of polylactic acid or modified polylactic acid and high molecular weight polyethylene oxide wherein the high molecular weight polyethylene oxide is present in the range of from about 2% by weight to about 50% by weight, suitable for films. A method of applying an active material selected from the class of seeds, seedlings, pesticides, herbicides, fertilizers and mixtures thereof to an agricultural site is also disclosed.

  6. Water and UV degradable lactic acid polymers

    SciTech Connect

    Bonsignore, P.V.; Coleman, R.D.

    1990-06-26

    A water and UV light degradable copolymer of monomers of lactic acid and a modifying monomer selected from the class consisting of ethylene and polyethylane glycols (PVB 6/22/90), propylene and and polypropylene (PVB 6/22/90) glycols, P-dioxanone, 1, 5 dioxepan-2-one, 1,4 -oxathialan-2-one, 1,4-dioxide and mixtures thereof. These copolymers are useful for waste disposal and agricultural purposes. Also disclosed is a water degradable blend of polylactic acid or modified polylactic acid and high molecular weight polyethylene oxide wherein the high molecular weight polyethylene oxide is present in the range of from about 2% by weight to about 50% by weight, suitable for films. A method of applying an active material selected from the class of seeds, seedlings, pesticides, herbicides, fertilizers and mixtures thereof to an agricultural site is also disclosed.

  7. Production of Insecticide Degradates in Juices: Implications for Risk Assessment.

    PubMed

    Radford, Samantha A; Panuwet, Parinya; Hunter, Ronald E; Barr, Dana Boyd; Ryan, P Barry

    2016-06-01

    This study was designed to observe the production of degradates of two organophosphorus insecticides and one pyrethroid insecticide in beverages. Purified water, white grape juice, apple juice, and red grape juice were fortified with 500 ng/g malathion, chlorpyrifos, and permethrin, and aliquots were extracted for malathion dicarboxylic acid (MDA), 3,5,6-trichloro-2-pyridinol (TCPy), and 3-phenoxybenzoic acid (3-PBA) several times over a 15 day period of being stored in the dark at 2.5 °C. Overall, first-order kinetics were observed for production of MDA, and statistically significant production of TCPy was also observed. Statistically significant production of 3-phenoxybenzoic acid was not observed. Results indicate that insecticides degrade in food and beverages, and this degradation may lead to preexisting insecticide metabolites in the beverages. Therefore, it is suggested that caution should be exercised when using urinary insecticide metabolites to assess exposure and risk. PMID:27213611

  8. Degradation of CYANEX 301 in Contact with Nitric Acid Media

    SciTech Connect

    Philippe Marc; Radu Custelcean; Gary S. Groenewold; John R. Klaehn; Dean R. Peterman; Laetitia H. Delmau

    2012-10-01

    The nature of the degradation product obtained upon contacting CYANEX 301 (bis(2,4,4-trimethylpentyl)dithiophosphinic acid) with nitric acid has been elucidated and found to be a disulfide derivative. The first step to the degradation of CYANEX 301 in toluene has been studied using 31P{1H} NMR after being contacted with nitric acid media. The spectrum of the degradation product exhibits a complex multiplet around dP = 80 ppm. A succession of purifications of CYANEX 301 has resulted in single crystals of the acidic form and the corresponding ammonium salt. Unlike the original CYANEX 301, which consists of a complex diastereomeric mixture displaying all possible combinations of chiral orientations at the 2-methyl positions, the purified crystals were shown by single-crystal X-ray diffraction to be racemates, containing 50:50 mixtures of the [R;R] and [S;S] diastereomers. The comparison between the 31P {1H} NMR spectra of the degradation products resulting from the diastereomerically pure CYANEX 301 and the original diastereomeric mixture has elucidated the influence of the isomeric composition on the multiplicity of the 31P {1H} NMR peak. These NMR data indicate the initial degradation leads to a disulfide-bridged condensation product displaying multiple resonances due to phosphorus–phosphorus coupling, which is caused by the inequivalence of the two P atoms as a result of their different chirality. A total of nine different NMR resonances, six of which display phosphorus–phosphorus coupling, could be assigned, and the identity of the peaks corresponding to phosphorus atoms coupled to each other was confirmed by 31P {1H} homodecoupled NMR analysis.

  9. Microbial degradation of usnic acid in the reindeer rumen.

    PubMed

    Sundset, Monica A; Barboza, Perry S; Green, Thomas K; Folkow, Lars P; Blix, Arnoldus Schytte; Mathiesen, Svein D

    2010-03-01

    Reindeer (Rangifer tarandus) eat and utilize lichens as an important source of energy and nutrients in winter. Lichens synthesize and accumulate a wide variety of phenolic secondary compounds, such as usnic acid, as a defense against herbivores and to protect against damage by UV-light in solar radiation. We have examined where and to what extent these phenolic compounds are degraded in the digestive tract of the reindeer, with particular focus on usnic acid. Three male reindeer were given ad libitum access to a control diet containing no usnic acid for three weeks and then fed lichens ad libitum (primarily Cladonia stellaris) containing 9.1 mg/g DM usnic acid for 4 weeks. Usnic acid intake in reindeer on the lichen diet was 91-117 mg/kg BM/day. In spite of this, no trace of usnic acid or conjugates of usnic acid was found either in fresh rumen fluid, urine, or feces. This suggests that usnic acid is rapidly degraded by rumen microbes, and that it consequently is not absorbed by the animal. This apparent ability to detoxify lichen phenolic compounds may gain increased importance with future enhanced UV-B radiation expected to cause increased protective usnic acid/phenol production in lichens.

  10. Microbial degradation of usnic acid in the reindeer rumen

    NASA Astrophysics Data System (ADS)

    Sundset, Monica A.; Barboza, Perry S.; Green, Thomas K.; Folkow, Lars P.; Blix, Arnoldus Schytte; Mathiesen, Svein D.

    2010-03-01

    Reindeer ( Rangifer tarandus) eat and utilize lichens as an important source of energy and nutrients in winter. Lichens synthesize and accumulate a wide variety of phenolic secondary compounds, such as usnic acid, as a defense against herbivores and to protect against damage by UV-light in solar radiation. We have examined where and to what extent these phenolic compounds are degraded in the digestive tract of the reindeer, with particular focus on usnic acid. Three male reindeer were given ad libitum access to a control diet containing no usnic acid for three weeks and then fed lichens ad libitum (primarily Cladonia stellaris) containing 9.1 mg/g DM usnic acid for 4 weeks. Usnic acid intake in reindeer on the lichen diet was 91-117 mg/kg BM/day. In spite of this, no trace of usnic acid or conjugates of usnic acid was found either in fresh rumen fluid, urine, or feces. This suggests that usnic acid is rapidly degraded by rumen microbes, and that it consequently is not absorbed by the animal. This apparent ability to detoxify lichen phenolic compounds may gain increased importance with future enhanced UV-B radiation expected to cause increased protective usnic acid/phenol production in lichens.

  11. Ultrasonic degradation of oxalic acid in aqueous solutions.

    PubMed

    Dükkanci, M; Gündüz, G

    2006-09-01

    This paper describes the ultrasonic degradation of oxalic acid. The effects of ultrasonic power, H(2)O(2), NaCl, external gases on the degradation of oxalic acid were investigated. Reactor flask containing oxalic acid was immersed in the ultrasonic bath with water as the coupling fluid. Representative samples withdrawn were analysed by volumetric titration. Degradation degree of oxalic acid increased with increasing ultrasonic power. It was observed that H(2)O(2) has negative contribution on the degradation of oxalic acid and there was an optimum concentration of NaCl for enhancing the degradation degree of oxalic acid. Although bubbling nitrogen gave higher degradation than that for bubbling air, both gases (for 20 min before sonication and during sonication together) could not help to enhance the degradation of oxalic acid when compared with the degradation without gas passage. PMID:16352455

  12. Materials degradation caused by acid rain

    SciTech Connect

    Baboian, R.

    1986-01-01

    This book is the result of a symposium sponsored by the Division of Industrial and Engineering Chemistry, Inc. at the 20th State-of-the-Art Symposium of the American Chemical Society, Arlington, Virginia, June 17-19, 1985. The papers represent the state of our knowledge about materials problems resulting from acid deposition as we understand it through the Federal assessment efforts. The book is a must for those interested in the progress of the ongoing National Acid Precipitation Assessment Program. The volume contains 29 separately authored papers in 5 sections: Measurement and Monitoring of Atmospheric Deposition (5 papers), Metallic Corrosion (9 papers), Masonry Deterioration (7 papers), Degradation of Organics (3 papers), and Economic Effects (5 papers). The papers are assembled in such a way as to introduce the reader to the scope and nature of the atmospheric deposition (acid rain) problem. For those interested in how man and his technology are affecting our environment, this collection of papers establishes what information is available to better understand how materials degrade differently in an ambient environment enriched in anthropogenic NO/sup 3 -/ and SO/sub 4//sup 2 -/, their precursors, and associated forms and ions. The papers weave a tale about a complex international and global problem of acidification that has potential to affect exposed building materials.

  13. Poly(lactic acid) degradable plastics, coatings, and binders

    SciTech Connect

    Bonsignore, P.V.; Coleman, R.D.; Mudde, J.P.

    1992-05-01

    Biochemical processes to derive value from the management of high carbohydrate food wastes, such as potato starch, corn starch, and cheese whey permeate, have typically been limited to the production of either ethanol or methane. Argonne National Laboratory (ANL) believes that lactic acid presents an attractive option for an alternate fermentation end product, especially in light of lactic acids` being a viable candidate for conversion to environmentally safe poly(lactic acid) (PLA) degradable plastics, coatings, and binders. Technology is being developed at ANL to permit a more cost effective route to modified high molecular weight PLA. Preliminary data on the degradation behavior of these modified PLAs shows the retention to the inherent hydrolytic degradability of the PLA modified, however, by introduced compositional variables. A limited study was done on the hydrolytic stability of soluble oligomers of poly(L-lactic acid). Over a 34 day hold period, water-methanol solutions of Pl-LA oligomers in the 2-10 DP range retained some 75% of their original molecular weight.

  14. Poly(lactic acid) degradable plastics, coatings, and binders

    SciTech Connect

    Bonsignore, P.V.; Coleman, R.D.; Mudde, J.P.

    1992-01-01

    Biochemical processes to derive value from the management of high carbohydrate food wastes, such as potato starch, corn starch, and cheese whey permeate, have typically been limited to the production of either ethanol or methane. Argonne National Laboratory (ANL) believes that lactic acid presents an attractive option for an alternate fermentation end product, especially in light of lactic acids' being a viable candidate for conversion to environmentally safe poly(lactic acid) (PLA) degradable plastics, coatings, and binders. Technology is being developed at ANL to permit a more cost effective route to modified high molecular weight PLA. Preliminary data on the degradation behavior of these modified PLAs shows the retention to the inherent hydrolytic degradability of the PLA modified, however, by introduced compositional variables. A limited study was done on the hydrolytic stability of soluble oligomers of poly(L-lactic acid). Over a 34 day hold period, water-methanol solutions of Pl-LA oligomers in the 2-10 DP range retained some 75% of their original molecular weight.

  15. High Modulus Biodegradable Polyurethanes for Vascular Stents: Evaluation of Accelerated in vitro Degradation and Cell Viability of Degradation Products

    PubMed Central

    Sgarioto, Melissa; Adhikari, Raju; Gunatillake, Pathiraja A.; Moore, Tim; Patterson, John; Nagel, Marie-Danielle; Malherbe, François

    2015-01-01

    We have recently reported the mechanical properties and hydrolytic degradation behavior of a series of NovoSorb™ biodegradable polyurethanes (PUs) prepared by varying the hard segment (HS) weight percentage from 60 to 100. In this study, the in vitro degradation behavior of these PUs with and without extracellular matrix (ECM) coating was investigated under accelerated hydrolytic degradation (phosphate buffer saline; PBS/70°C) conditions. The mass loss at different time intervals and the effect of aqueous degradation products on the viability and growth of human umbilical vein endothelial cells (HUVEC) were examined. The results showed that PUs with HS 80% and below completely disintegrated leaving no visual polymer residue at 18 weeks and the degradation medium turned acidic due to the accumulation of products from the soft segment (SS) degradation. As expected the PU with the lowest HS was the fastest to degrade. The accumulated degradation products, when tested undiluted, showed viability of about 40% for HUVEC cells. However, the viability was over 80% when the solution was diluted to 50% and below. The growth of HUVEC cells is similar to but not identical to that observed with tissue culture polystyrene standard (TCPS). The results from this in vitro study suggested that the PUs in the series degraded primarily due to the SS degradation and the cell viability of the accumulated acidic degradation products showed poor viability to HUVEC cells when tested undiluted, however particles released to the degradation medium showed cell viability over 80%. PMID:26000274

  16. Benzoic acid degradation of polyacrylonitrile fibers

    NASA Technical Reports Server (NTRS)

    Varma, D. S.; Needles, H. L.; Cagliostro, D. E.

    1981-01-01

    The reactions of polyacrylonitrile (PAN) fibers in the presence of benzoic acid have been studied. Polyacrylonitrile fibers oxidize more readily in the presence of benzoic acid than in air at temperatures in the range of 170 C. The product decreased in solubility with extent of reaction. Gel permeation chromatography of the soluble fraction showed change in polydispersity. The insoluble product exhibited differences in weight loss as a function of decomposition temperature compared to PAN fibers. Infrared analyses of the fiber product showed absorption peaks similar to air-oxidized PAN. High-energy photoelectron spectral analysis showed a carbon-rich surface which contained oxygen and nitrogen. An air oxidized sample of fiber contained more oxygen at the surface than a fiber treated first with benzoic acid and then air oxidized.

  17. PRODUCTION OF TRIFLUOROACETIC ACID

    DOEpatents

    Haworth, W.N.; Stacey, M.

    1949-07-19

    A method is given for the production of improved yields of trifluoroacetic acid. The compound is prepared by oxidizing m-aminobenzotrifluoride with an alkali metal or alkaline earth metal permanganate at a temperature in the range of 80 deg C to 100 deg C while dissolved ln a mixture of water with glacial acetic acid and/or trifluoroacetic acid. Preferably a mixture of water and trifluoroacetic acid ls used as the solvent.

  18. Anthocyanins degradation during storage of Hibiscus sabdariffa extract and evolution of its degradation products.

    PubMed

    Sinela, André; Rawat, Nadirah; Mertz, Christian; Achir, Nawel; Fulcrand, Hélène; Dornier, Manuel

    2017-01-01

    Degradation parameters of two main anthocyanins from roselle extract (Hibiscus sabdariffa L.) stored at different temperatures (4-37°C) over 60days were determined. Anthocyanins and some of their degradation products were monitored and quantified using HPLC-MS and DAD. Degradation of anthocyanins followed first-order kinetics and reaction rate constants (k values), which were obtained by non-linear regression, showed that the degradation rate of delphinidin 3-O-sambubioside was higher than that of cyanidin 3-O-sambubioside with k values of 9.2·10(-7)s(-1) and 8.4·10(-7)s(-1) at 37°C respectively. The temperature dependence of the rate of anthocyanin degradation was modeled by the Arrhenius equation. Degradation of delphinidin 3-O-sambubioside (Ea=90kJmol(-1)) tended to be significantly more sensitive to an increase in temperature than cyanidin 3-O-sambubioside (Ea=80kJmol(-1)). Degradation of these anthocyanins formed scission products (gallic and protocatechuic acids respectively) and was accompanied by an increase in polymeric color index. PMID:27507471

  19. Amino Acid Degradation after Meteoritic Impact Simulation

    NASA Technical Reports Server (NTRS)

    Bertrand, M.; Westall, F.; vanderGaast, S.; Vilas, F.; Hoerz, F.; Barnes, G.; Chabin, A.; Brack, A.

    2008-01-01

    Amino acids are among the most important prebiotic molecules as it is from these precursors that the building blocks of life were formed [1]. Although organic molecules were among the components of the planetesimals making up the terrestrial planets, large amounts of primitive organic precursor molecules are believed to be exogenous in origin and to have been imported to the Earth via micrometeorites, carbonaceous meteorites and comets, especially during the early stages of the formation of the Solar System [1,2]. Our study concerns the hypothesis that prebiotic organic matter, present on Earth, was synthesized in the interstellar environment, and then imported to Earth by meteorites or micrometeorites. We are particularly concerned with the formation and fate of amino acids. We have already shown that amino acid synthesis is possible inside cometary grains under interstellar environment conditions [3]. We are now interested in the effects of space conditions and meteoritic impact on these amino acids [4-6]. Most of the extraterrestrial organic molecules known today have been identified in carbonaceous chondrite meteorites [7]. One of the components of these meteorites is a clay with a composition close to that of saponite, used in our experiments. Two American teams have studied the effects of impact on various amino acids [8,9]. [8] investigated amino acids in saturated solution in water with pressure ranges between 5.1 and 21 GPa and temperature ranges between 412 and 870 K. [9] studied amino acids in solid form associated with and without minerals (Murchison and Allende meteorite extracts) and pressure ranges between 3 and 30 GPa. In these two experiments, the amino acids survived up to 15 GPa. At higher pressure, the quantity of preserved amino acids decreases quickly. Some secondary products such as dipeptides and diketopiperazins were identified in the [8] experiment.

  20. Perfluorooctanoic Acid Degradation Using UV-Persulfate Process: Modeling of the Degradation and Chlorate Formation.

    PubMed

    Qian, Yajie; Guo, Xin; Zhang, Yalei; Peng, Yue; Sun, Peizhe; Huang, Ching-Hua; Niu, Junfeng; Zhou, Xuefei; Crittenden, John C

    2016-01-19

    In this study, we investigated the destruction and by-product formation of perfluorooctanoic acid (PFOA) using ultraviolet light and persulfate (UV-PS). Additionally, we developed a first-principles kinetic model to simulate both PFOA destruction and by-product and chlorate (ClO3(-)) formation in ultrapure water (UW), surface water (SW), and wastewater (WW). PFOA degradation was significantly suppressed in the presence of chloride and carbonate species and did not occur until all the chloride was converted to ClO3(-) in UW and for low DOC concentrations in SW. The model was able to simulate the PS decay, pH changes, radical concentrations, and ClO3(-) formation for UW and SW. However, our model was unable to simulate PFOA degradation well in WW, possibly from PS activation by NOM, which in turn produced sulfate radicals. PMID:26686982

  1. Phenolic acid degradation potential and growth behavior of lactic acid bacteria in sunflower substrates.

    PubMed

    Fritsch, Caroline; Heinrich, Veronika; Vogel, Rudi F; Toelstede, Simone

    2016-08-01

    Sunflower flour provides a high content of protein with a well-balanced amino acid composition and is therefore regarded as an attractive source for protein. The use for human nutrition is hindered by phenolic compounds, mainly chlorogenic acid, which can lead under specific circumstances to undesirable discolorations. In this study, growth behavior and degradation ability of chlorogenic acid of four lactic acid bacteria were explored. Data suggested that significant higher fermentation performances on sunflower flour as compared to sunflower protein concentrate were reached by Lactobacillus plantarum, Pediococcus pentosaceus, Lactobacillus gasseri and Bifidobacterium animalis subsp. lactis. In fermentation with the latter two strains reduced amounts of chlorogenic acid were observed in sunflower flour (-11.4% and -19.8%, respectively), which were more pronounced in the protein concentrate (-50.7% and -95.6%, respectively). High tolerances against chlorogenic acid and the cleavage product quinic acid with a minimum inhibitory concentration (MIC) of ≥20.48 mg/ml after 48 h were recorded for all strains except Bifidobacterium animalis subsp. lactis, which was more sensitive. The second cleavage compound, caffeic acid revealed a higher antimicrobial potential with MIC values of 0.64-5.12 mg/ml. In this proof of concept study, degradation versus inhibitory effect suggest the existence of basic mechanisms of interaction between phenolic acids in sunflower and lactic acid bacteria and a feasible way to reduce the chlorogenic acid content, which may help to avoid undesired color changes.

  2. Degradation and Isotope Source Tracking of Glyphosate and Aminomethylphosphonic Acid.

    PubMed

    Li, Hui; Joshi, Sunendra R; Jaisi, Deb P

    2016-01-27

    Glyphosate [N-(phosphonomethyl) glycine], an active ingredient of the herbicide Roundup, and its main metabolite, aminomethylphosphonic acid (AMPA), have been frequently reported to be present in soils and other environments and thus have heightened public concerns on their potential adverse effects. Understanding the fate of these compounds and differentiating them from other naturally occurring compounds require a toolbox of methods that can go beyond conventional methods. Here, we applied individual isotope labeling technique whereby each compound or mineral involved in the glyphosate and AMPA degradation reaction was either synthesized or chosen to have distinct (18)O/(16)O ratios so that the source of incorporated oxygen in the orthophosphate generated and corresponding isotope effect during C-P bond cleavage could be identified. Furthermore, we measured original isotope signatures of a few commercial glyphosate sources to identify their source-specific isotope signatures. Our degradation kinetics results showed that the rate of glyphosate degradation was higher than that of AMPA in all experimental conditions, and both the rate and extent of degradation were lowest under anoxic conditions. Oxygen isotope ratios (δ(18)OP) of orthophosphate generated from glyphosate and AMPA degradation suggested that one external oxygen atom from ambient water, not from dissolved oxygen or mineral, was incorporated into orthophosphate with the other three oxygen atoms inherited from the parent molecule. Interestingly, δ(18)OP values of all commercial glyphosate products studied were found to be the lightest among all orthophosphates known so far. Furthermore, isotope composition was found to be unaffected due to variable degradation kinetics, light/dark, and oxic/anoxic conditions. These results highlight the importance of phosphate oxygen isotope ratios as a nonconventional tool to potentially distinguish glyphosate sources and products from other organophosphorus compounds

  3. Degradation and Isotope Source Tracking of Glyphosate and Aminomethylphosphonic Acid.

    PubMed

    Li, Hui; Joshi, Sunendra R; Jaisi, Deb P

    2016-01-27

    Glyphosate [N-(phosphonomethyl) glycine], an active ingredient of the herbicide Roundup, and its main metabolite, aminomethylphosphonic acid (AMPA), have been frequently reported to be present in soils and other environments and thus have heightened public concerns on their potential adverse effects. Understanding the fate of these compounds and differentiating them from other naturally occurring compounds require a toolbox of methods that can go beyond conventional methods. Here, we applied individual isotope labeling technique whereby each compound or mineral involved in the glyphosate and AMPA degradation reaction was either synthesized or chosen to have distinct (18)O/(16)O ratios so that the source of incorporated oxygen in the orthophosphate generated and corresponding isotope effect during C-P bond cleavage could be identified. Furthermore, we measured original isotope signatures of a few commercial glyphosate sources to identify their source-specific isotope signatures. Our degradation kinetics results showed that the rate of glyphosate degradation was higher than that of AMPA in all experimental conditions, and both the rate and extent of degradation were lowest under anoxic conditions. Oxygen isotope ratios (δ(18)OP) of orthophosphate generated from glyphosate and AMPA degradation suggested that one external oxygen atom from ambient water, not from dissolved oxygen or mineral, was incorporated into orthophosphate with the other three oxygen atoms inherited from the parent molecule. Interestingly, δ(18)OP values of all commercial glyphosate products studied were found to be the lightest among all orthophosphates known so far. Furthermore, isotope composition was found to be unaffected due to variable degradation kinetics, light/dark, and oxic/anoxic conditions. These results highlight the importance of phosphate oxygen isotope ratios as a nonconventional tool to potentially distinguish glyphosate sources and products from other organophosphorus compounds

  4. Determination of Glyphosate, its Degradation Product Aminomethylphosphonic Acid, and Glufosinate, in Water by Isotope Dilution and Online Solid-Phase Extraction and Liquid Chromatography/Tandem Mass Spectrometry

    USGS Publications Warehouse

    Meyer, Michael T.; Loftin, Keith A.; Lee, Edward A.; Hinshaw, Gary H.; Dietze, Julie E.; Scribner, Elisabeth A.

    2009-01-01

    The U.S. Geological Survey method (0-2141-09) presented is approved for the determination of glyphosate, its degradation product aminomethylphosphonic acid (AMPA), and glufosinate in water. It was was validated to demonstrate the method detection levels (MDL), compare isotope dilution to standard addition, and evaluate method and compound stability. The original method USGS analytical method 0-2136-01 was developed using liquid chromatography/mass spectrometry and quantitation by standard addition. Lower method detection levels and increased specificity were achieved in the modified method, 0-2141-09, by using liquid chromatography/tandem mass spectrometry (LC/MS/MS). The use of isotope dilution for glyphosate and AMPA and pseudo isotope dilution of glufosinate in place of standard addition was evaluated. Stable-isotope labeled AMPA and glyphosate were used as the isotope dilution standards. In addition, the stability of glyphosate and AMPA was studied in raw filtered and derivatized water samples. The stable-isotope labeled glyphosate and AMPA standards were added to each water sample and the samples then derivatized with 9-fluorenylmethylchloroformate. After derivatization, samples were concentrated using automated online solid-phase extraction (SPE) followed by elution in-line with the LC mobile phase; the compounds separated and then were analyzed by LC/MS/MS using electrospray ionization in negative-ion mode with multiple-reaction monitoring. The deprotonated derivatized parent molecule and two daughter-ion transition pairs were identified and optimized for glyphosate, AMPA, glufosinate, and the glyphosate and AMPA stable-isotope labeled internal standards. Quantitative comparison between standard addition and isotope dilution was conducted using 473 samples analyzed between April 2004 and June 2006. The mean percent difference and relative standard deviation between the two quantitation methods was 7.6 plus or minus 6.30 (n = 179), AMPA 9.6 plus or minus 8

  5. Gluconic acid production.

    PubMed

    Anastassiadis, Savas; Morgunov, Igor G

    2007-01-01

    Gluconic acid, the oxidation product of glucose, is a mild neither caustic nor corrosive, non toxic and readily biodegradable organic acid of great interest for many applications. As a multifunctional carbonic acid belonging to the bulk chemicals and due to its physiological and chemical characteristics, gluconic acid itself, its salts (e.g. alkali metal salts, in especially sodium gluconate) and the gluconolactone form have found extensively versatile uses in the chemical, pharmaceutical, food, construction and other industries. Present review article presents the comprehensive information of patent bibliography for the production of gluconic acid and compares the advantages and disadvantages of known processes. Numerous manufacturing processes are described in the international bibliography and patent literature of the last 100 years for the production of gluconic acid from glucose, including chemical and electrochemical catalysis, enzymatic biocatalysis by free or immobilized enzymes in specialized enzyme bioreactors as well as discontinuous and continuous fermentation processes using free growing or immobilized cells of various microorganisms, including bacteria, yeast-like fungi and fungi. Alternatively, new superior fermentation processes have been developed and extensively described for the continuous and discontinuous production of gluconic acid by isolated strains of yeast-like mold Aureobasidium pullulans, offering numerous advantages over the traditional discontinuous fungi processes.

  6. [Degradation of oxytetracycline with ozonation in acetic acid solvent].

    PubMed

    Li, Shi-Yin; Li, Xiao-Rong; Zhu, Yi-Ping; Zhu, Jiang-Peng; Wang, Guo-Xiang

    2012-12-01

    Use acetic acid as the media of ozone degradation of oxytetracycline (OTC), and effects of the initial dosing ratio of ozone/OTC, ozone flow, free radical scavenger, metal ions on the removal rate of OTC were investigated respectively. The results showed that acetic acid had a high ozone stability and solubility. OTC had a high removal rate and degradation rate in acetic acid solution. With the increase of OTC dosage, the removal rate of OTC decreased in acetic acid. Removal rate of OTC was increased distinctly when ozone flow increased properly. It was also observed that free radical scavenger had a significantly negative effect on OTC ozonation degradation in acetic acid. Furthermore the main reactions of OTC ozone oxidation were direct oxidation and indirect oxidation in acetic acid. When Fe3+ and Co2+ were existent in acetic acid, the degradation of OTC was inhibited significantly.

  7. Oxidative degradation of organic acids conjugated with sulfite oxidation in flue gas desulfurization

    SciTech Connect

    Lee, Y.I.

    1986-01-01

    Organic acid degradation conjugated with sulfite oxidation has been studied under flue gas desulfurization (EGD) conditions. The oxidative degradation constant, k/sub 12/, is defined as the ratio of organic acid degradation rate and sulfite oxidation rate after being normalized by the concentrations of organic acid and dissolved S(IV). K/sub 12/, not significantly affected by pH or dissolved oxygen, is around 10/sup -3/ in the absence of manganese or iron. However, k/sub 12/ is increased by certain transition metals such as Co, Ni, and Fe and is decreased by Mn and halides. Lower dissolved S(IV) magnified these effects. No k/sub 12/ greater than 4 x 10/sup -3/ or smaller than 0.1 x 10/sup -3/ has been observed. A free radical mechanism was proposed to describe the kinetics: (1) sulfate free radical is the major radical responsible to the degradation of organic acid; (2) ferrous generates sulfate radical by reacting with monoxypersulfate to enhance k/sub 12/; (3) manganous consumes sulfate radical to decrease k/sub 12/; (4) dissolved S(IV) competes with ferrous for monoxypersulfate and with manganous for sulfate radical to demonstrate the effects of dissolved S(IV) on k/sub 12/. Hydroxy and sulfonated carboxylic acids degrade approximately three times slower than saturated dicarboxylic acids; while maleic acid, an unsaturated dicarboxylic acid, degraded an order of magnitude faster. A wide spectrum of degradation products of adipic acid were found, including carbon dioxide - the major product, glutaric semialdehyde - the major retained product with low manganese, glutaric acid and valeric acids - the major retained product with high manganese, lower molecular weight mono- and dicarboxylic acids, other carbonyl compounds, and hydrocarbons.

  8. The abiotic degradation of soil organic matter to oxalic acid

    NASA Astrophysics Data System (ADS)

    Studenroth, Sabine; Huber, Stefan; Schöler, H. F.

    2010-05-01

    degradation of catechol to oxalic acid delivers a maximum yield of approximately 60 %, whereas the presence of chloride reduces the formation of oxalic acid to 30 %. Chloride possibly induces further competing reactions of catechol leading to a lower concentration of oxalic acid. Freeze-dried soil samples have been tested for production of oxalic acid, where the rate of organic matter seems to play an important role for the formation. By adding iron (III) and/or hydrogen peroxide oxalic acid yields increase, which demonstrates the reaction of soil organic matter with iron (III) and hydrogen peroxide as expected. Thus the natural abiotic formation of oxalic acid is confirmed. The results of the soil measurements are similar to those obtained with catechol. Therefore, the newly gained insights with model compounds appear to be applicable to soil conditions and these findings increase our understanding of the degradation pathways of soil organic matter. Furthermore an overview of the rates of oxalic acid formation of a variety of soil samples is shown and discussed in the light of different soil parameter.

  9. [Catalytic ozonation by ceramic honeycomb for the degradation of oxalic acid in aqueous solution].

    PubMed

    Zhao, Lei; Sun, Zhi-Zhong; Ma, Jun

    2007-11-01

    Comparative experiments for the degradation of oxalic acid in aqueous solution were carried out in the three processes of ozonation alone, ceramic honeycomb-catalyzed ozonation and ceramic honeycomb adsorption. The results show that the degradation rates of oxalic acid in the ceramic honeycomb-catalyzed ozonation, ozonation alone and ceramic honeycomb adsorption systems are 37.6%, 2.2% and 0.4%, and the presence of ceramic honeycomb catalyst significantly improves the degradation rate of oxalic acid compared to the results from non-catalytic ozonation and adsorption. With the addition of tert-butanol, the degradation rates of oxalic acid in catalytic ozonation system decrease by 24.1%, 29.0% and 30.1%, respectively, at the concentration of 5, 10 and 15 mg x L(-1). This phenomenon indicates that ceramic honeycomb-catalyzed ozonation for the degradation of oxalic acid in aqueous solution follows the mechanism of *OH oxidation, namely the heterogeneous surface of catalyst enhances the initiation of *OH. The results of TOC analysis demonstrate that the process of ceramic honeycomb-catalyzed ozonation can achieve the complete mineralization level without the formation of intermediary degradation products. The experimental results suggest that the reaction temperature has positive relationship with the degradation rate of oxalic acid. The degradation rates of oxalic acid in the ceramic honeycomb-catalyzed ozonation system are 16.4%, 37.6%, 61.3% and 68.2%, at the respective reaction temperature of 10, 20, 30 and 40 degrees C.

  10. Production of a polyester degrading extracellular hydrolase from Thermomonospora fusca.

    PubMed

    Gouda, Mona K; Kleeberg, Ilona; van den Heuvel, Joop; Müller, Rolf-Joachim; Deckwer, Wolf-Dieter

    2002-01-01

    The production of a polyester-degrading hydrolase from the thermophilic actinomycete Thermomonospora fusca was investigated with regard to its potential technical application. Only in the presence of a polyester (random aliphatic-aromatic copolyester from 1,4-butanediol, terephthalic acid, and adipic acid with around 40-50 mol % terephthalic acid in the acid component), the excretion of the extracellular enzyme could be achieved with an optimized synthetic medium using pectin and NH(4)Cl as nitrogen source. Compared to complex media, a significantly higher specific activity at comparable volumetric yields could be obtained, thus reducing the expenditure for purification. The activity profile in the medium is controlled by a complex process involving (1) induction of enzyme excretion, (2) enzyme adsorption on the hydrophobic polyester surface, (3) inhibition of enzyme generation by monomers produced by polyester cleavage, and (4) enzyme denaturation. Diafiltration with cellulose acetate membranes as the sole downstream processing step led to a product of high purity and with sufficient yield (60% of total activity). Scaling-up from shaking flasks to a fermentor scale of 100 L revealed no specific problems. However, the excretion of the hydrolase by the actinomycete turned out to be inhibited by the degradation products (monomers) of the aliphatic-aromatic copolyester used as inductor for the enzyme production. The crude enzyme exhibited generally similar properties (temperature and pH optimum) as the highly purified hydrolase described previously; however, the storage capability and thermal stability is improved when the crude enzyme solution is diafiltrated.

  11. [Degradation pathways and main degradation products of tetracycline antibiotics: research progress].

    PubMed

    Li, Wei-Ming; Bao, Yan-Yu; Zhou, Qi-Xing

    2012-08-01

    Tetracycline antibiotics (TCs) can produce a series of abiotic degradation reactions in the process of production and storage, and some of the degradation products have lower antibacterial activity but higher toxicity, as compared to the parent antibiotics. TCs can enter the environment via the disposal of livestock and poultry wastes, and then degrade in one or more ways according to the external conditions. Besides abiotic degradation, bio-degradation also happens. This paper reviewed the degradation pathways and main degradation products of TCs in different ecological environments, and discussed the future research directions, aimed to provide valuable reference for the ecological risk assessment of the antibiotics.

  12. Evaluation of genotoxicity and pro-oxidant effect of the azo dyes: acids yellow 17, violet 7 and orange 52, and of their degradation products by Pseudomonas putida mt-2.

    PubMed

    Ben Mansour, Hedi; Corroler, David; Barillier, Daniel; Ghedira, Kamel; Chekir, Leila; Mosrati, Ridha

    2007-09-01

    Acids yellow 17, violet 7 and orange 52, very important commercial azo dyes used in the textile, food, paper and cosmetic industries, were degraded by Pseudomonas putida mt-2 at concentrations up to 100mg/l. The culture media was completely decolorized under static incubation for 60 h, this faster than under continuous shaking incubation. SOS chromotest using Escherichia coli PQ37, with and without metabolic activation (S-9 preparations), was used to assess genotoxicity potential of these dyes before and after biodegradation. None of these dyes or their metabolites was found to be genotoxic in the absence of "Araclor-Induced rat liver microsome" preparations (S-9). However, in presence of the preparation S-9, the genotoxicity of the biodegradation products was highlighted. Metabolites resulting from static cultures were more genotoxic than those obtained in shaken conditions. In addition to genotoxic effects, metabolites have shown a significant ability to induce the formation of superoxide free radical anion (O(2)(*-)). The toxicities generated by the pure azo dyes and the pure azo-reduction products (sulfanilic acid, N,N'-dimethyl-p-phenylenediamine and 4'-aminoacetanilid) were compared. These results suggest that P. putida mt-2 degrades the studied azo dyes in two steps: an azo-reduction followed by an oxygen-dependent metabolization. Some of the derived metabolites would be responsible of genotoxicity and metabolic toxicity.

  13. Degradation of hop bitter acids by fungi

    SciTech Connect

    Huszcza, Ewa Bartmanska, Agnieszka; Aniol, Miroslaw; Maczka, Wanda; Zolnierczyk, Anna; Wawrzenczyk, Czeslaw

    2008-07-01

    Nine fungal strains related to: Trametes versicolor, Nigrospora oryzae, Inonotus radiatus, Crumenulopsis sororia, Coryneum betulinum, Cryptosporiopsis radicicola, Fusarium equiseti, Rhodotorula glutinis and Candida parapsilosis were tested for their ability to degrade humulones and lupulones. The best results were obtained for T. versicolor culture, in which humulones and lupulones were fully degraded after 4 days of incubation in the dark or after 36 h in the light. The experiments were performed on a commercial hop extract and on sterilized spent hops.

  14. Phenolic acid degradation potential and growth behavior of lactic acid bacteria in sunflower substrates.

    PubMed

    Fritsch, Caroline; Heinrich, Veronika; Vogel, Rudi F; Toelstede, Simone

    2016-08-01

    Sunflower flour provides a high content of protein with a well-balanced amino acid composition and is therefore regarded as an attractive source for protein. The use for human nutrition is hindered by phenolic compounds, mainly chlorogenic acid, which can lead under specific circumstances to undesirable discolorations. In this study, growth behavior and degradation ability of chlorogenic acid of four lactic acid bacteria were explored. Data suggested that significant higher fermentation performances on sunflower flour as compared to sunflower protein concentrate were reached by Lactobacillus plantarum, Pediococcus pentosaceus, Lactobacillus gasseri and Bifidobacterium animalis subsp. lactis. In fermentation with the latter two strains reduced amounts of chlorogenic acid were observed in sunflower flour (-11.4% and -19.8%, respectively), which were more pronounced in the protein concentrate (-50.7% and -95.6%, respectively). High tolerances against chlorogenic acid and the cleavage product quinic acid with a minimum inhibitory concentration (MIC) of ≥20.48 mg/ml after 48 h were recorded for all strains except Bifidobacterium animalis subsp. lactis, which was more sensitive. The second cleavage compound, caffeic acid revealed a higher antimicrobial potential with MIC values of 0.64-5.12 mg/ml. In this proof of concept study, degradation versus inhibitory effect suggest the existence of basic mechanisms of interaction between phenolic acids in sunflower and lactic acid bacteria and a feasible way to reduce the chlorogenic acid content, which may help to avoid undesired color changes. PMID:27052717

  15. Production of degradable polymers from food-waste streams

    SciTech Connect

    Tsai, S.P.: Coleman, R.D.; Bonsignore, P.V.; Moon, S.H.

    1992-01-01

    In the United States, billions of pounds of cheese whey permeate and approximately 10 billion pounds of potatoes processed each year are typically discarded or sold as cattle feed at $3{endash}6/ton; moreover, the transportation required for these means of disposal can be expensive. As a potential solution to this economic and environmental problem, Argonne National Laboratory is developing technology that: Biologically converts existing food-processing waste streams into lactic acid and uses lactic acid for making environmentally safe, degradable polylactic acid (PLA) and modified PLA plastics and coatings. An Argonne process for biologically converting high-carbohydrate food waste will not only help to solve a waste problem for the food industry, but will also save energy and be economically attractive. Although the initial substrate for Argonne's process development is potato by-product, the process can be adapted to convert other food wastes, as well as corn starch, to lactic acid. Proprietary technology for biologically converting greater than 90% of the starch in potato wastes to glucose has been developed. Glucose and other products of starch hydrolysis are subsequently fermented by bacteria that produce lactic acid. The lactic acid is recovered, concentrated, and further purified to a polymer-grade product.

  16. Production of degradable polymers from food-waste streams

    SciTech Connect

    Tsai, S.P.: Coleman, R.D.; Bonsignore, P.V.; Moon, S.H.

    1992-07-01

    In the United States, billions of pounds of cheese whey permeate and approximately 10 billion pounds of potatoes processed each year are typically discarded or sold as cattle feed at $3{endash}6/ton; moreover, the transportation required for these means of disposal can be expensive. As a potential solution to this economic and environmental problem, Argonne National Laboratory is developing technology that: Biologically converts existing food-processing waste streams into lactic acid and uses lactic acid for making environmentally safe, degradable polylactic acid (PLA) and modified PLA plastics and coatings. An Argonne process for biologically converting high-carbohydrate food waste will not only help to solve a waste problem for the food industry, but will also save energy and be economically attractive. Although the initial substrate for Argonne`s process development is potato by-product, the process can be adapted to convert other food wastes, as well as corn starch, to lactic acid. Proprietary technology for biologically converting greater than 90% of the starch in potato wastes to glucose has been developed. Glucose and other products of starch hydrolysis are subsequently fermented by bacteria that produce lactic acid. The lactic acid is recovered, concentrated, and further purified to a polymer-grade product.

  17. Degradation of 4-chlorophenylacetic acid by a Pseudomonas species.

    PubMed Central

    Klages, U; Markus, A; Lingens, F

    1981-01-01

    Pseudomonas sp. strain CBS3 was able to utilize 4-chlorophenylacetic acid as the sole source of carbon and energy. When this strain was grown with 4-chlorophenylacetic acid, homoprotocatechuic acid was found to be an intermediate which was further metabolized by the meta-cleavage pathway. Furthermore, three isomers of chlorohydroxyphenylacetic acid, two of them identified as 3-chloro-4-hydroxyphenylacetic acid and 4-chloro-3-hydroxyphenylacetic acid, were isolated from the culture medium. 4-Hydroxyphenylacetic acid was catabolized in a different manner by the glutathione-dependent homogentisate pathway. Degradation enzymes of both of these pathways were inducible. PMID:7217006

  18. Novel pathway for degradation of protocatechuic acid in Bacillus species.

    PubMed

    Crawford, R L

    1975-02-01

    A species of Bacillus, tentatively identified as B. circulans, degrades protocatechuic acid by a novel reaction involving meta-fission between C2 and C3 of the benzene nucleus. 2-Hydroxymuconic semialdehyde is then degraded to pyruvate and acetaldehyde by enzymatic reactions described in previous work. Protocatechuate 2,3-oxygenase exhibits a rather narrow substrate specificity; the methyl and ethyl esters of protocatechuic acid are oxidized, but other substrates for ring-fission oxygenases, notably catechol, gallic acid, and homoprotocatechuic acid, are not attached.

  19. Photolytic and photocatalytic degradation of tetracycline: Effect of humic acid on degradation kinetics and mechanisms.

    PubMed

    Li, Si; Hu, Jiangyong

    2016-11-15

    The widespread occurrence of tetracycline (TC) in the aquatic environment poses a potential risk to aquatic ecosystem and human health. In this study, elimination of TC by photolysis and TiO2 photocatalysis were investigated by using mercury-free UVA-LED as an alternative light source. Particular emphasis was given to the effect of humic acid (HA) on the reaction kinetics and mechanisms of TC removal. Photolytic degradation of TC was slightly enhanced by HA due to its photosensitization effect, as evidenced by the increased steady-state concentrations of OH. The most abundant transformation product of TC, which was formed by the attack of OH radical, was enhanced during photolytic degradation. During photocatalytic experiments, HA dramatically inhibited TC loss due to the surface deactivation of TiO2 and OH quenching. The steady-state concentration of OH was dramatically decreased in the presence of HA. Identification of transformation products showed that HA could inhibit the oxidation pathways initiated by OH during photocatalysis of TC. These findings provide further insights into the assessment of photolysis and photocatalysis for antibiotics elimination in natural waters where HA exists ubiquitously. PMID:27420385

  20. Critical factors in sonochemical degradation of fumaric acid.

    PubMed

    Wu, Zhilin; Cravotto, Giancarlo; Adrians, Marcus; Ondruschka, Bernd; Li, Weixin

    2015-11-01

    The effects of critical factors such as Henry's Law constant, atmospheric OH rate constant, initial concentration, H2O2, FeSO4 and tert-butanol on the sonochemical degradation of fumaric acid have been investigated. The pseudo first-order rate constant for the sonochemical degradation of 1mM fumaric acid is much lower than those for chloroform and phenol degradation, and is related to solute concentration at the bubble/water interface and reactivity towards hydroxyl radicals. Furthermore, fumaric acid is preferentially oxidized at the lower initial concentration. It is unreactive to H2O2 under agitation at room temperature. However, the degradation rate of fumaric acid increases with the addition of H2O2 under sonication. 0.1 mM of fumaric acid suppresses H2O2 formation thanks to water sonolysis, while degradation behavior is also dramatically affected by the addition of an oxidative catalyst (FeSO4) or radical scavenger (tert-butanol), indicating that the degradation of fumaric acid is caused by hydroxyl radicals generated during the collapse of high-energy cavities. PMID:26186831

  1. Polysorbate 20 Degradation in Biopharmaceutical Formulations: Quantification of Free Fatty Acids, Characterization of Particulates, and Insights into the Degradation Mechanism.

    PubMed

    Tomlinson, Anthony; Demeule, Barthélemy; Lin, Baiwei; Yadav, Sandeep

    2015-11-01

    Polysorbate 20 (PS20), a commonly used surfactant in biopharmaceuticals, showed degradation upon long-term (∼18-36 months) storage of two monoclonal antibody (mAb, mAb-A, and mAb-B) drug products at 2-8 °C. The PS20 degradation resulted in the accumulation of free fatty acids (FFA), which ultimately precipitated to form particles upon long-term storage. This study documents the development, qualification, and application of a method for FFA quantification in soluble and insoluble fraction of protein formulation. The method was applied to the quantification of capric acid, lauric acid, myristic acid, palmitic/oleic acid, and stearic acid in placebo as well as active protein formulations on stability. Quantification of FFA in both the soluble and insoluble fraction of mAb-A and mAb-B provided a better mechanistic understanding of PS20 degradation and the dynamics of subsequent fatty acid particle formation. Additionally, the use of this method for monitoring and quantitation of the FFA on real time storage stability appears to aid in identifying batches with higher probability for particulate formation upon extended storage at 5 °C. PMID:26419339

  2. Kinetics of acid-catalyzed degradation of cyclosporin A and its analogs in aqueous solution.

    PubMed

    Oliyai, R; Safadi, M; Meier, P G; Hu, M K; Rich, D H; Stella, V J

    1994-03-01

    The kinetics and mechanism of the degradation of cyclosporin A have been studied under aqueous acidic conditions. The rate of degradation was found to be specific acid-catalyzed over the pH range studied (1-4), with isocyclosporin A as the predominant degradation product. Selective reduction of the olefinic bond of the amino acid 2-N-methyl-(R)-((E)-2-butenyl)-4-methyl-L-threonine (MeBmt) did not affect the overall degradation kinetics and product distribution of cyclosporin A. These observations indicate that the alternative degradation pathway involving intramolecular alkoxy addition to the olefinic bond of amino acid MeBmt apparently does not significantly contribute to the overall degradation kinetics of cyclosporin A in the pH range 1-4. The chemical reactivity of O-acetyl-cyclosporin A was examined to probe the governing mechanism for the isomerization of cyclosporin A. Under identical conditions, O-acetyl-cyclosporin A showed a much greater chemical stability than cyclosporin A, consistent with a mechanism involving the hydroxyoxazolidine intermediate. The chemical stability of cyclosporin C, which contains two beta-hydroxyl groups, was also examined. The rate and product distribution for the degradation of cyclosporin C suggest that under aqueous acidic conditions it undergoes N,O-acyl migration solely at the amino acid residue MeBmt. Additionally, the impact of side-chain bulkiness of amino acid MeBmt was examined by studying the degradation kinetics of a series of cyclosporin A analogs.(ABSTRACT TRUNCATED AT 250 WORDS)

  3. Determination of the degree of acetylation and the distribution of acetyl groups in chitosan by HPLC analysis of nitrous acid degraded and PMP labeled products.

    PubMed

    Han, Zhangrun; Zeng, Yangyang; Lu, Hong; Zhang, Lijuan

    2015-09-01

    Chitin is one of the most abundant polysaccharides on earth. It consists of repeating β-1,4 linked N-acetylated glucosamine (A) units. Chitosan is an N-deacetylated product of chitin. Chitosan and its derivatives have broad medical applications as drugs, nutraceuticals, or drug delivery agents. However, a reliable analytical method for quality control of medically used chitosans is still lacking. In current study, nitrous acid was used to cleave all glucosamine residues in chitosan into 2,5-anhydromannose (M) or M at the reducing end of di-, tri-, and oligosaccharides. PMP, i.e. 1-phenyl-3-methyl-5-pyrazolone, was used to label all the Ms. Online UV detection allowed quantification of all M-containing UV peaks whereas online MS analysis directly identified 11 different kinds of mono-, di-, tri-, and oligosaccharides that correlated each oligosaccharide with specific UV peak after HPLC separation. The DA (degree of acetylation) for chitosans was calculated based on the A/(A+M) value derived from the UV data. This newly developed method had several advantages for quality control of chitosan: 1. the experimental procedures were extensively optimized; 2. the reliability of the method was confirmed by online LC-MS analysis; 3. the DA value was obtainable based on the UV data after HPLC analysis, which was comparableto that of (1)H NMR and conductometric titration analyses; 4. finally and most importantly, this method could be used to obtain the DA as well as chemical acetylation/deacetylation mechanisms for chitosan by any laboratory equipped with a HPLC and an online UV detector.

  4. Influence of Fenton's reagent doses on the degradation and mineralization of H-acid.

    PubMed

    Liu, Huanhuan; Chen, Quanyuan; Yu, Yang; Liu, Zhenhong; Xue, Gang

    2013-12-15

    The recalcitrant H-acid (1-amino-8-naphthol-3,6-disulfonic acid) in aqueous solution was oxidized by Fenton process, focusing on the relation of Fenton's reagent doses and degradation products. The experimental results showed that COD and TOC removals and biodegradability (BOD/COD ratio) of the solution increased with increasing Fenton's reagent doses. Over 80% COD can be removed and the biodegradability was improved significantly. It was found that major SO3H and NH2 groups in H-acid molecules were mineralized to SO4(2-) and NH4(+) ions during Fenton oxidation processes. H-acid degradation intermediates with benzene structures substituted by hydroxyl and/or carboxyl groups were identified by GC-MS. It was also found that short-chain fatty acids primarily oxalic acid were degradation products of H-acid by Fenton oxidation. Oxalic acid accumulated could account for approximately 60% of the residual TOC. The degradation pathway of H-acid was proposed based on above analyses in this work. PMID:24231329

  5. Degradation of h-acid by free and immobilized cells of Alcaligenes latus

    PubMed Central

    Usha, M.S.; Sanjay, M.K.; Gaddad, S.M.; Shivannavar, C.T.

    2010-01-01

    Alcaligenes latus, isolated from industrial effluent, was able to grow in mineral salts medium with 50 ppm (0.15 mM) of H-acid as a sole source of carbon. Immobilization of Alcaligenes latus in Ca-alginate and polyurethane foam resulted in cells embedded in the matrices. When free cells and immobilized cells were used for biodegradation studies at concentration ranging from 100 ppm (0.3 mM) to 500 ppm (1.15 mM) degradation rate was enhanced with immobilized cells. Cells immobilized in polyurethane foam showed 100% degradation up to 350 ppm (1.05 mM) and 57% degradation at 500 ppm (1.5 mM). Degradation rate of Ca-alginate immobilized cells was less as compared to that of polyurethane foam immobilized cells. With Ca-alginate immobilized cells 100% degradation was recorded up to 200 ppm (0.6 mM) of H-acid and only 33% degradation was recorded at 500 ppm (1.5 mM) of H-acid. Spectral analysis of the products after H-acid utilization showed that the spent medium did not contain any aromatic compounds indicating H-acid degradation by A. latus. PMID:24031573

  6. Synthesis and degradation test of hyaluronic acid hydrogels.

    PubMed

    Hahn, Sei Kwang; Park, Jung Kyu; Tomimatsu, Takashi; Shimoboji, Tsuyoshi

    2007-03-10

    Hyaluronic acid (HA) hydrogels prepared with three different crosslinking reagents were assessed by in vitro and in vivo degradation tests for various tissue engineering applications. Adipic acid dihydrazide grafted HA (HA-ADH) was synthesized and used for the preparation of methacrylated HA (HA-MA) with methacrylic anhydride and thiolated HA (HA-SH) with Traut's reagent (imminothiolane). (1)H NMR analysis showed that the degrees of HA-ADH, HA-MA, and HA-SH modification were 69, 29, and 56 mol%, respectively. HA-ADH hydrogel was prepared by the crosslinking with bis(sulfosuccinimidyl) suberate (BS(3)), HA-MA hydrogel with dithiothreitol (DTT) by Michael addition, and HA-SH hydrogel with sodium tetrathionate by disulfide bond formation. According to in vitro degradation tests, HA-SH hydrogel was degraded very fast, compared to HA-ADH and HA-MA hydrogels. HA-ADH hydrogel was degraded slightly faster than HA-MA hydrogel. Based on these results, HA-MA hydrogels and HA-SH hydrogels were implanted in the back of SD rats and their degradation was assessed according to the pre-determined time schedule. As expected from the in vitro degradation test results, HA-SH hydrogel was in vivo degraded completely only in 2 weeks, whereas HA-MA hydrogels were degraded only partially even in 29 days. The degradation rate of HA hydrogels were thought to be controlled by changing the crosslinking reagents and the functional group of HA derivatives. In addition, the state of HA hydrogel was another factor in controlling the degradation rate. Dried HA hydrogel at 37 degrees C for a day resulted in relatively slow degradation compared to the bulk HA hydrogel. There was no adverse effect during the in vivo tests. PMID:17101173

  7. Phytic acid degrading lactic acid bacteria in tef-injera fermentation.

    PubMed

    Fischer, Maren M; Egli, Ines M; Aeberli, Isabelle; Hurrell, Richard F; Meile, Leo

    2014-11-01

    Ethiopian injera, a soft pancake, baked from fermented batter, is preferentially prepared from tef (Eragrostis tef) flour. The phytic acid (PA) content of tef is high and is only partly degraded during the fermentation step. PA chelates with iron and zinc in the human digestive tract and strongly inhibits their absorption. With the aim to formulate a starter culture that would substantially degrade PA during injera preparation, we assessed the potential of microorganisms isolated from Ethiopian household-tef fermentations to degrade PA. Lactic acid bacteria (LAB) were found to be among the dominating microorganisms. Seventy-six isolates from thirteen different tef fermentations were analyzed for phytase activity and thirteen different isolates of seven different species were detected to be positive in a phytase screening assay. In 20-mL model tef fermentations, out of these thirteen isolates, the use of Lactobacillus (L.) buchneri strain MF58 and Pediococcus pentosaceus strain MF35 resulted in lowest PA contents in the fermented tef of 41% and 42%, respectively of its initial content. In comparison 59% of PA remained when spontaneously fermented. Full scale tef fermentation (0.6L) and injera production using L. buchneri MF58 as culture additive decreased PA in cooked injera from 1.05 to 0.34±0.02 g/100 g, representing a degradation of 68% compared to 42% in injera from non-inoculated traditional fermentation. The visual appearance of the pancakes was similar. The final molar ratios of PA to iron of 4 and to zinc of 12 achieved with L. buchneri MF58 were decreased by ca. 50% compared to the traditional fermentation. In conclusion, selected LAB strains in tef fermentations can degrade PA, with L. buchneri MF58 displaying the highest PA degrading potential. The 68% PA degradation achieved by the application of L. buchneri MF58 would be expected to improve human zinc absorption from tef-injera, but further PA degradation is probably necessary if iron absorption has to

  8. The influences of elastomer toward degradability of poly (lactic acid)

    NASA Astrophysics Data System (ADS)

    Kaavessina, Mujtahid; Distantina, Sperisa; Chafidz, Achmad; Fadilah, Al-Zahrani, Saeed M.

    2016-02-01

    Poly (lactic acid)/elastomer blends were prepared via direct injection molding with the different weight fractions of elastomer, namely: 0, 10, 20 and 30 wt%. Degradation test of poly (lactic acid) (PLA) was performed by burial in the soil. The physical appearance and thermal properties of the tested specimens were monitored periodically. The presence of elastomer tended to significantly increase the degradability of PLA after buried for 27 weeks. With 30 wt% elastomer, the color and the surface of specimens become more white and rougher due to the degradation. Differential scanning calorimetry (DSC) was used to evaluate thermal properties and crystallinity of all samples. It was found that the melting temperature decreased as the amount of elastomer increased. The crystallinity showed that the degradation of PLA is occurred firstly in amorphous phase.

  9. Selective determination of ertapenem in the presence of its degradation product

    NASA Astrophysics Data System (ADS)

    Hassan, Nagiba Y.; Abdel-Moety, Ezzat M.; Elragehy, Nariman A.; Rezk, Mamdouh R.

    2009-06-01

    Stability-indicative determination of ertapenem (ERTM) in the presence of its β-lactam open-ring degradation product, which is also the metabolite, is investigated. The degradation product has been isolated, via acid-degradation, characterized and elucidated. Selective quantification of ERTM, singly in bulk form, pharmaceutical formulations and/or in the presence of its major degradant is demonstrated. The indication of stability has been undertaken under conditions likely to be expected at normal storage conditions. Among the spectrophotometric methods adopted for quantification are first derivative ( 1D), first derivative of ratio spectra ( 1DD) and bivariate analysis.

  10. Separation and characterization of forced degradation products of abacavir sulphate by LC-MS/MS.

    PubMed

    Rao, R Nageswara; Vali, R Mastan; Ramachandra, Bondigalla; Raju, S Satyanarayana

    2011-01-25

    Abacavir sulphate was subjected to forced degradation under the conditions of hydrolysis (acid, alkali and neutral), oxidation, photolysis and thermal stress as prescribed by ICH. Eight degradation products were formed and their separation was accomplished on Waters XTerra C₁₈ (250 mm x 4.6 mm, 5 μm) column using 20 mM ammonium acetate:acetonitrile as a mobile phase in gradient elution mode by LC. The degradation products were characterized by LC-MS/MS and its fragmentation pathways were proposed. No previous reports were found in the literature regarding the degradation behavior of abacavir sulphate.

  11. The role of purine degradation in methane biosynthesis and energy production in Methanococcus vannielii

    SciTech Connect

    DeMoll, E.

    1990-10-22

    Research continues on the role of purine degradation in methane biosynthesis and energy production in Methanococcus vannielii. This report summarizes current progress of the research. Topics include: A survey of other methanogens for the purine degradation pathway; isolate and characterize the enzyme and products of formiminoglycine cleavage; ascertain the fate of glycine from the formiminoglycine cleavage; elucidate the route of incorporation of the formyl moiety of formiminoglycine into methane biosynthesis; determine the percent methane and amino acid synthesis from purine degradation; and related studies on xanthine dehydrogenase and pyrimidine degradation of M. Vannielii. (SM)

  12. Degradation of acid orange 7 in an aerobic biofilm.

    PubMed

    Coughlin, Michael F; Kinkle, Brian K; Bishop, Paul L

    2002-01-01

    A stable microbial biofilm community capable of completely mineralizing the azo dye acid orange 7 (AO7) was established in a laboratory scale rotating drum bioreactor (RDBR) using waste liquor from a sewage treatment plant. A broad range of environmental conditions including pH (5.8-8.2), nitrification (0.0-4.0 mM nitrite), and aeration (0.2-6.2 mg O2 l(-1)) were evaluated for their effects on the biodegradation of AO7. Furthermore the biofilm maintained its biodegradative ability for over a year while the effects of these environmental conditions were evaluated. Reduction of the azo bond followed by degradation of the resulting aromatic amine appears to be the mechanism by which this dye is biodegraded. Complete loss of color, sulfanilic acid, and chemical oxygen demand (COD) indicate that AO7 is mineralized. To our knowledge this is the first reported occurrence of a sulfonated phenylazonaphthol dye being completely mineralized under aerobic conditions. Two bacterial strains (ICX and SAD4i) originally isolated from the RDBR were able to mineralize, in co-culture, up to 90% of added AO7. During mineralization of AO7, strain ICX reduces the azo bond under aerobic conditions and consumes the resulting cleavage product 1-amino-2-naphthol. Strain SAD4i consumes the other cleavage product, sulfanilic acid. The ability of the RDBR biofilm to aerobically mineralize an azo dye without exogenous carbon and nitrogen sources suggests that this approach could be used to remediate industrial wastewater contaminated with spent dye.

  13. Chemical Degradation Studies on a Series of Dithiophosphinic Acids

    SciTech Connect

    Freiderich, Melissa E; Delmau, Laetitia Helene; Peterman, D. R.; Marc, Philippe L; Klaehn, John D.

    2014-01-01

    In this study a significant increase in the stability of a series of dithiophosphinic acids (DPAHs) under oxidizing acidic conditions was achieved. The degradation behavior of a series of DPAHs, designed for lanthanide/actinide separation, was examined. The stability of the DPAHs, when contacted with varying nitric acid concentrations, was tested and monitored using 31P {1H} NMR. Changes in the functional groups of the DPAHs resulted in substantial increases in the stability. However, all the DPAHs eventually showed signs of degradation when placed in contact with 2 M HNO3. The addition of a radical scavenger, hydrazine, inhibited the degradation of the DPAHs. With small amounts of hydrazine, five of the DPAHs remained stable for over a month in direct contact with 2 M HNO3.

  14. Chemical Degradation Studies on a Series of Dithiophosphinic Acids

    SciTech Connect

    Melissa E. Freiderich; Dean R. Peterman; John R. Klaehn; Philippe Marc; Laetitia H. Delmau

    2014-04-01

    A significant increase in the stability of a series of dithiophosphinic acids (DPAHs) under oxidizing acidic conditions was achieved. The degradation behavior of a series of DPAHs, designed for lanthanide/actinide separation, was examined. The stability of the DPAHs, when contacted with varying nitric acid concentrations, was tested and monitored using 31P {1H} NMR. Changes in the functional groups of the DPAHs resulted in substantial increases in the stability. However, when placed in contact with 2 M HNO3 all the DPAHs eventually showed signs of degradation. The addition of a radical scavenger, hydrazine, inhibited the degradation of the DPAHs. In the presence of a small concentration of hydrazine, five of the DPAHs remained stable for over a month in direct contact with 2 M HNO3.

  15. [Degradation of Acid Orange 7 with Persulfate Activated by Silver Loaded Granular Activated Carbon].

    PubMed

    Wang, Zhong-ming; Huang, Tian-yin; Chen, Jia-bin; Li, Wen-wei; Zhang, Li-ming

    2015-11-01

    Granular activated carbon with silver loaded as activator (Ag/GAC) was prepared using impregnation method. N2 adsorption, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) were adopted to characterize the Ag/GAC, showing that silver was successfully loaded on granular activated carbon. The oxidation degradation of acid orange 7 (AO7) by the Ag/GAC activated by persulfate (PS) was investigated at ambient temperature. The influences of factors such as Ag loading, PS or Ag/GAC dosages and initial pH on the degradation of AO7 were evaluated. The results demonstrated that the degradation rate of AO7 could reach more than 95.0% after 180 min when the Ag loading content, PS/AO7 molar ratio, the Ag/GAC dosage were 12.7 mg x g(-1), 120: 1, 1.0 g x L(-1), respectively. The initial pH had significant effect on the AO7 degradation, with pH 5.0 as the optimal pH for the degradation of AO7. The possible degradation pathway was proposed for the AO7 degradation by using UV-visible spectroscopy and gas chromatography-mass spectrometry (GG/MS). The azo bond and naphthalene ring in the AO7 were destroyed during the degradation, with phthalic acid and acetophenone as the main degradation products. PMID:26910999

  16. Anaerobic degradation of veratrylglycerol-beta-guaiacyl ether and guaiacoxyacetic acid by mixed rumen bacteria.

    PubMed Central

    Chen, W; Supanwong, K; Ohmiya, K; Shimizu, S; Kawakami, H

    1985-01-01

    Veratrylglycerol-beta-guaiacyl ether (0.2 g/liter), a lignin model compound, was found to be degraded by mixed rumen bacteria in a yeast extract medium under strictly anaerobic conditions to the extent of 19% within 24 h. Guaiacoxyacetic acid, 2-(o-methoxyphenoxy)ethanol, vanillic acid, and vanillin were detected as degradation products of veratrylglycerol-beta-guaiacyl ether by thin-layer chromatography, gas chromatography, and gas chromatography-mass spectrometry. Guaiacoxyacetic acid (0.25 g/liter), when added into the medium as a substrate, was entirely degraded within 36 h, resulting in the formation of phenoxyacetic acid, guaiacol, and phenol. These results suggest that the beta-arylether bond, an important intermonomer linkage in lignin, can be cleaved completely by these rumen anaerobes. PMID:3841472

  17. Toxicology of atmospheric degradation products of selected hydrochlorofluorocarbons

    NASA Technical Reports Server (NTRS)

    Kaminsky, Laurence S.

    1990-01-01

    Trifluoroacetic acid (TFA) is a liquid with a sharp biting odor. It has been proposed as the product of environmental degradation of the hydrochlorofluorocarbons HCFC-123, HCFC-124, HFC-134a, and HFC-125. Compounds HCFC-141b and HCFC-142b could yield mixed fluorochloroacetic acids, for which there is no available toxicologic data. The release of hydrochlorofluorocarbons into the environment could also give rise to HF, but the additional fluoride burden (1 to 3 ppb) in rainwater is trivial compared to levels in fluoridated drinking water (1 ppm), and would provide an insignificant risk to humans. Thus, in this paper only the toxocologic data on TFA is reviewed to assess the potential risks of environmental exposure.

  18. Glycolic acid modulates the mechanical property and degradation of poly(glycerol, sebacate, glycolic acid).

    PubMed

    Sun, Zhi-Jie; Wu, Lan; Huang, Wei; Chen, Chang; Chen, Yan; Lu, Xi-Li; Zhang, Xiao-Lan; Yang, Bao-Feng; Dong, De-Li

    2010-01-01

    The development of biodegradable materials with controllable degradation properties is beneficial for a variety of applications. Poly(glycerol-sebacate) (PGS) is a promising candidate of biomaterials; so we synthesize a series of poly(glycerol, sebacate, glycolic acid) (PGSG) with 1:2:0, 1:2:0.2, 1:2:0.4, 1:2:0.6, 1:2:1 mole ratio of glycerol, sebacate, and glycolic acid to elucidate the relation of doped glycolic acid to the degradation rate and mechanical properties. The microstructures of the polymers with different doping of glycolic acid were dissimilar. PGSG with glycolic acid in the ratio of 0.2 displayed an integral degree of ordering, different to those with glycolic acid in the ratio of 0, 0.4, 0.6, and 1, which showed mild phase separation structure. The number, DeltaH(m), and temperature of the PGSG melting peaks tended to decrease with the increasing ratio of doped glycolic acid. In vitro and in vivo degradation tests showed that the degradation rate of PGSG with glycolic acid in the ratio of 0.2 was slowest, but in the ratio range of 0, 0.4, and 0.6, the degradation rate increased with the increase of glycolic acid. All PGSG samples displayed good tissue response and anticoagulant effects. Our data suggest that doping glycolic acid can modulate the microstructure and degree of crosslinking of PGS, thereby control the degradation rate of PGS.

  19. Stability of nicotinate and dodecyl sulfate in a Lewis acidic ionic liquid for aluminum electroplating and characterization of their degradation products.

    PubMed

    Kosmus, Patrick; Steiner, Oliver; Goessler, Walter; Gollas, Bernhard; Fauler, Gisela

    2016-04-01

    Plating bath additives are essential for optimization of the morphology of electroplated layers. The ionic liquid 1-ethyl-3-methylimidazolium (EMIM) chloride plus 1.5 mol equivalents of AlCl3 has great potential for electroplating of aluminum. In this study, the chemical and electrochemical stability of the additives EMIM-nicotinate and sodium dodecyl sulfate and their effect on the stability of EMIM was investigated and analyzed. Nicotinate and its electrochemical decomposition product β-picoline could be detected and we show with a single HPLC-UV-MS method that EMIM is not affected by the decomposition of this additive. An adapted standard HPLC-UV-MS method together with GC-MS and ion chromatography was used to analyze the decomposition products of SDS and possible realkylation products of EMIM. Several volatile medium and short chain-length alkanes as well as sulfate ions have been found as decomposition products of SDS. Alkenium ions formed as intermediates during the decomposition of SDS realkylate EMIM to produce mono- up to pentasubstituted alkyl-imidazoles. A reaction pathway involving Wagner-Meerwein rearrangements and Friedel-Crafts alkylations has been suggested to account for the formation of the detected products.

  20. Stability of nicotinate and dodecyl sulfate in a Lewis acidic ionic liquid for aluminum electroplating and characterization of their degradation products.

    PubMed

    Kosmus, Patrick; Steiner, Oliver; Goessler, Walter; Gollas, Bernhard; Fauler, Gisela

    2016-04-01

    Plating bath additives are essential for optimization of the morphology of electroplated layers. The ionic liquid 1-ethyl-3-methylimidazolium (EMIM) chloride plus 1.5 mol equivalents of AlCl3 has great potential for electroplating of aluminum. In this study, the chemical and electrochemical stability of the additives EMIM-nicotinate and sodium dodecyl sulfate and their effect on the stability of EMIM was investigated and analyzed. Nicotinate and its electrochemical decomposition product β-picoline could be detected and we show with a single HPLC-UV-MS method that EMIM is not affected by the decomposition of this additive. An adapted standard HPLC-UV-MS method together with GC-MS and ion chromatography was used to analyze the decomposition products of SDS and possible realkylation products of EMIM. Several volatile medium and short chain-length alkanes as well as sulfate ions have been found as decomposition products of SDS. Alkenium ions formed as intermediates during the decomposition of SDS realkylate EMIM to produce mono- up to pentasubstituted alkyl-imidazoles. A reaction pathway involving Wagner-Meerwein rearrangements and Friedel-Crafts alkylations has been suggested to account for the formation of the detected products. PMID:26864607

  1. Advice on Degradation Products in Pharmaceuticals: A Toxicological Evaluation.

    PubMed

    Melo, Sâmia Rocha de Oliveira; Homem-de-Mello, Maurício; Silveira, Dâmaris; Simeoni, Luiz Alberto

    Degradation products are unwanted chemicals that can develop during the manufacturing, transportation, and storage of drug products and can affect the efficacy of pharmaceutical products. Moreover, even small amounts of degradation products can affect pharmaceutical safety because of the potential to cause adverse effects in patients. Consequently, it is crucial to focus on mechanistic understanding, formulation, storage conditions, and packaging to prevent the formation of degradation products that can negatively affect the quality and safety of the drug product. In this sense, databases and software that help predict the reactions involving the pharmaceutically active substance in the presence of degradation conditions can be used to obtain information on major degradation routes and the main degradation products formed during pharmaceutical product storage. In some cases, when the presence of a genotoxic degradation product is verified, it is necessary to conduct more thorough assessments. It is important to consider the chemical structure to distinguish between compounds with toxicologically alerting structures with associated toxic/genotoxic risks and compounds without active structures that can be treated as ordinary impurities. Evaluating the levels of degradation products based on a risk/benefit analysis is mandatory. Controlling critical variables during early development of drug products and conducting a follow-up study of these impurities can prevent degradation impurities present at concentrations greater than threshold values to ensure product quality. The definition of the impurity profile has become essential per various regulatory requirements. Therefore, this review includes the international regulatory perspective on impurity documents and the toxicological evaluation of degradation products. Additionally, some techniquesused in the investigation of degradation products and stability-indicating assay methods are highlighted.

  2. Advice on Degradation Products in Pharmaceuticals: A Toxicological Evaluation.

    PubMed

    Melo, Sâmia Rocha de Oliveira; Homem-de-Mello, Maurício; Silveira, Dâmaris; Simeoni, Luiz Alberto

    Degradation products are unwanted chemicals that can develop during the manufacturing, transportation, and storage of drug products and can affect the efficacy of pharmaceutical products. Moreover, even small amounts of degradation products can affect pharmaceutical safety because of the potential to cause adverse effects in patients. Consequently, it is crucial to focus on mechanistic understanding, formulation, storage conditions, and packaging to prevent the formation of degradation products that can negatively affect the quality and safety of the drug product. In this sense, databases and software that help predict the reactions involving the pharmaceutically active substance in the presence of degradation conditions can be used to obtain information on major degradation routes and the main degradation products formed during pharmaceutical product storage. In some cases, when the presence of a genotoxic degradation product is verified, it is necessary to conduct more thorough assessments. It is important to consider the chemical structure to distinguish between compounds with toxicologically alerting structures with associated toxic/genotoxic risks and compounds without active structures that can be treated as ordinary impurities. Evaluating the levels of degradation products based on a risk/benefit analysis is mandatory. Controlling critical variables during early development of drug products and conducting a follow-up study of these impurities can prevent degradation impurities present at concentrations greater than threshold values to ensure product quality. The definition of the impurity profile has become essential per various regulatory requirements. Therefore, this review includes the international regulatory perspective on impurity documents and the toxicological evaluation of degradation products. Additionally, some techniquesused in the investigation of degradation products and stability-indicating assay methods are highlighted. PMID:25188345

  3. [Study on cooperating degradation of cypermethrin and 3-phenoxybenzoic acid by two bacteria strains].

    PubMed

    Xu, Yu-Xin; Sun, Ji-Quan; Li, Xiao-Hui; Li, Shun-Peng; Chen, Yi

    2007-10-01

    The microbial cooperated reaction is one of the most important forms of microbial degradation of organic pollutants. Although there were many research reports of cooperating degradation, less report on the microbial cooperated of pyrethroid degradation to be found. We have isolated one degrading-bacteria strain named CDT3 for degradation of cypermethrin, which can degraded the cypermethrin into 3-PBA and DCVA. At the same time, we also isolated another degrading-bacteria strain named as PBM11, which could get multiplication on 3-PBA as its C source and energy source. The cooperative degradation process of cypermethrin and 3-Phenoxybenzoic acid (3-PBA) using the two degrading-bacteria strain CDT3 and PBM11 was investigated. An obvious inhibition to the cypermethrin degrading-bacterium strain CDT3 (Rhodococcus sp.) by its metabolic mediate 3-PBA was found; meanwhile there is no effect on the growth of 3-PBA degrading-bacterium strain PBM11 (Pesudomonas sp.) when the concentration of cypermethrin was lower than 200 mg/L. The degradation rate of cypermethrin by both strain CDT3 and PBM11 was higher than that by CDT3 alone. The biomass of PBM11 increased along with the degradation of cypermethrin and 3-PBA, but that of CDT3 not. There was no the accumulation of 3-PBA when the simultaneous addition of strain CDT3 and PBM11, however, an obvious one within 24h if inoculation of strain PBM11 was later 24h after inoculation of strain CDT3, Subsequently the 3-PBA was degraded rapidly by strain PBM11. The strains CDT3 and PBM11 showed some characteristics of co-metabolism, however it is not actual degradation form of co-metabolism. For examples, although the degrading sub product of cypermethrin by CDT3 could be utilized, the multiplication of PBM11 could not enhance the multiplication of CDT3, implied there is no obvious relationship between the two strains. Also, to add PBM11 could eliminate the inhibition of 3-PBA to CDT3. Thus, the cooperating degradation of strains CDT3

  4. Citric acid production patent review.

    PubMed

    Anastassiadis, Savas; Morgunov, Igor G; Kamzolova, Svetlana V; Finogenova, Tatiana V

    2008-01-01

    Current Review article summarizes the developments in citric acid production technologies in East and West last 100 years. Citric acid is commercially produced by large scale fermentation mostly using selected fungal or yeast strains in aerobe bioreactors and still remains one of the runners in industrial production of biotechnological bulk metabolites obtained by microbial fermentation since about 100 years, reflecting the historical development of modern biotechnology and fermentation process technology in East and West. Citric acid fermentation was first found as a fungal product in cultures of Penicillium glaucum on sugar medium by Wehmer in 1893. Citric acid is an important multifunctional organic acid with a broad range of versatile uses in household and industrial applications that has been produced industrially since the beginning of 20(th) century. There is a great worldwide demand for citric acid consumption due to its low toxicity, mainly being used as acidulant in pharmaceutical and food industries. Global citric acid production has reached 1.4 million tones, increasing annually at 3.5-4.0% in demand and consumption. Citric acid production by fungal submerged fermentation is still dominating, however new perspectives like solid-state processes or continuous yeast processes can be attractive for producers to stand in today's strong competition in industry. Further perspectives aiming in the improvement of citric acid production are the improvement of citric acid producing strains by classical and modern mutagenesis and selection as well as downstream processes. Many inexpensive by-products and residues of the agro-industry (e.g. molasses, glycerin etc.) can be economically utilized as substrates in the production of citric acid, especially in solid-state fermentation, enormously reducing production costs and minimizing environmental problems. Alternatively, continuous processes utilizing yeasts which reach 200-250 g/l citric acid can stand in today

  5. Tannic acid degradation by Klebsiella strains isolated from goat feces

    PubMed Central

    Tahmourespour, Arezoo; Tabatabaee, Nooroldin; Khalkhali, Hossein; Amini, Imane

    2016-01-01

    Background and Objectives: Tannins are toxic polyphenols that either bind and precipitate or condense proteins. The high tannin content of some plants is the preliminary limitation of using them as a ruminant feed. So, the aim of this study was the isolation and characterization of tannic acid degrading bacterial strains from goat feces before and after feeding on Pistachio-Soft Hulls as tannin rich diet (TRD). Materials and Methods: Bacterial strains capable of utilizing tannic acid as sole carbon and energy source were isolated and characterized from goat feces before and after feeding on TRD. Tannase activity, maximum tolerable concentration and biodegradation potential were assessed. Results: Four tannase positive isolates were identified as Klebsiella pneumoniae. Isolated strains showed the maximum tolerable concentration of 64g/L of tannin. The tannic acid degradation percentage at a concentration of 15.0 g/L reached a maximum of 68% after 24 h incubation, and more than 98% after 72 h incubation. The pH of the medium also decreased along with tannic acid utilization. Conclusions: It is obvious that TRD induced adaptive responses. Thus, while the bacteria were able to degrade and detoxify the tannic acids, they had to adapt in the presence of high concentrations of tannic acid. So, these isolates have an amazing potential for application in bioremediation, waste water treatment, also reduction of tannins antinutritional effects in animal feeds. PMID:27092220

  6. Vibrational spectroscopy for online monitoring of extraction solvent degradation products

    SciTech Connect

    Peterson, J.; Robinson, T.; Bryan, S.A.; Levitskaia, T.G.

    2013-07-01

    In our research, we are exploring the potential of online monitoring of the organic solvents for the flowsheets relevant to the used nuclear fuel reprocessing and tributyl phosphate (TBP)- based extraction processes in particular. Utilization of vibrational spectroscopic techniques permits the discrimination of the degradation products from the primary constituents of the loaded extraction solvent. Multivariate analysis of the spectral data facilitates development of the regression models for their quantification in real time and potentially enables online implementation of a monitoring system. Raman and FTIR spectral databases were created and used to develop the regression partial least squares (PLS) chemometric models for the quantitative prediction of HDBP (dibutyl phosphoric acid) degradation product, TBP, and UO{sub 2}{sup 2+} extraction organic product phase. It was demonstrated that both these spectroscopic techniques are suitable for the quantification of the Purex solvent components in the presence of UO{sub 2}(NO{sub 3}){sub 2}. Developed PLS models successfully predicted HDBP and TBP organic concentrations in simulated Purex solutions.

  7. MONITORING AND MODELLING OF RADIOLYTIC DEGRADATION PRODUCTS OF TBP/n-DODECANE

    SciTech Connect

    Peterson, James M.; Levitskaia, Tatiana G.; Bryan, Samuel A.

    2011-10-03

    The Plutonium Uranium Extraction (PUREX) solvent system was developed for the separation of plutonium and uranium from irradiated fuel. Since the implementation of this process, the degradation chemistry associated with the irradiated solvent system, tributyl phosphate (TBP)/n-dodecane/nitric acid has been extensively studied as the integrity of the organic solvent is paramount for reproducible performance of the separation flowsheet (extraction/scrub/strip) during multiple cycles. In PUREX-like processes, the extent of decomposition is dependent not only upon the solvent, but also upon the presence of constituents, such as nitric acid, that interact with TBP and increase its susceptibility to radiolytic degradation. The build-up of degradation products in the organic phase alters process flowsheet performance via modification of the metal ions speciation, loss of solvent components, and enhanced water transport into the organic phase. On-line identification and quantification of the solvent degradation products would provide the necessary information for more detailed process control as well as providing the basis for timing solvent washing or replacement. In our research, we are exploring the potential of on-line monitoring for the PUREX solvent radiolytic degradation products. To identify degradation products, TBP/n-dodecane solvent, contacted with aqueous nitric acid solutions of variable concentrations are subjected to various gamma radiation external doses then analyzed by electro-spray ionization mass spectrometry (ESMS). In addition, vibrational spectroscopy is utilized to monitor and quantify major degradation products including dibutyl phosphoric acid (HDBP) and monobutyl phosphoric acid (H2MBP) in TBP/n-dodecane solvent. The compiled spectroscopic databases serve for developing interpretive and predictive chemometric models for the quantification of the PUREX solvent degradation products.

  8. Evaluating limiting steps of anaerobic degradation of food waste based on methane production tests.

    PubMed

    Ortega, Luis; Husser, Céline; Barrington, Suzelle; Guiot, Serge R

    2008-01-01

    This research adapted a batch test for biochemical methane production (BMP) to follow the degradation of complex compounds such as proteins and vegetable oils. The test measured the transformation of albumin and olive oil into methane under mesophilic and thermophilic conditions and assess limiting step in the overall degradation process. The thermophilic sludge used for the BMP tests was adapted during ten month from mesophilic sludge while being fed food waste. As compared to acetic acid, the specific rate of transformation of albumin and olive oil into methane reached 22 and 51%, respectively, under mesophilic conditions. Acetoclastic methanogenesis was not the limiting step in the presence of albumin or olive oil (and its monomer-like molecules such as amino acids, glycerol and oleic acid). Rather, the degradation of albumin was restricted by the presence of proteins. The thermophilically adapted sludge showed good proteolytic activity, but its acetoclastic methanogens were unable to degrade olive oil, because of the inhibitory effect of oleic acid.

  9. Degradation of trichloroethylene by hydrodechlorination using formic acid as hydrogen source over supported Pd catalysts.

    PubMed

    Yu, Xin; Wu, Ting; Yang, Xue-Jing; Xu, Jing; Auzam, Jordan; Semiat, Raphael; Han, Yi-Fan

    2016-03-15

    An advanced method for the degradation of trichloroethylene (TCE) over Pd/MCM-41 catalysts through a hydrogen-transfer was investigated. Formic acid (FA) was used instead of gaseous H2 as the hydrogen resource. As a model H-carrier compound, FA has proven to yield less by-products and second-hand pollution during the reaction. Several factors have been studied, including: the property of catalyst supports, Pd loading and size, temperature, initial concentrations of FA and TCE (potential impact on the reaction rates of TCE degradation), and FA decomposition. The intrinsic kinetics for TCE degradation were measured, while the apparent activation energies and the reaction orders with respect to TCE and FA were calculated through power law models. On the basis of kinetics, we assumed a plausible reaction pathway for TCE degradation in which the catalytic degradation of TCE is most likely the rate-determining step for this reaction. PMID:26685065

  10. Structural elucidation of degradation products of a benzopyridooxathiazepine under stress conditions using electrospray orbitrap mass spectrometry - study of degradation kinetic.

    PubMed

    Lecoeur, Marie; Vérones, Valérie; Vaccher, Claude; Bonte, Jean-Paul; Lebegue, Nicolas; Goossens, Jean-François

    2012-04-11

    1-(4-Methoxyphenylethyl)-11H-benzo[f]-1,2-dihydro-pyrido[3,2,c][1,2,5]oxathiazepine 5,5 dioxide (BZN) is a cytotoxic derivative with very promising in vitro activity. Regulatory authority for registration of pharmaceuticals for human use requires to evaluate the stability of active compound under various stress conditions. Forced degradation of BZN was investigated under hydrolytic (0.1M NaOH, 0.1M HCl, neutral), oxidative (3.3% H(2)O(2)), photolytic (visible light) and thermal (25 °C, 70 °C) settings. Relevant degradation took place under thermal acidic (0.1M HCl, 70 °C) and oxidative (3.3% H(2)O(2)) conditions. Liquid chromatography-mass spectrometry (LC-MS) analyses revealed the presence of ten degradation products whose structures were characterized by electrospray ionization-orbitrap mass spectrometry. The full scan accurate mass analysis of degradation products was confirmed or refuted using three tools furnished by the MS software: (1) predictive chemical formula and corresponding mass error; (2) double bond equivalent (DBE) calculation; and (3) accurate mass product ion spectra of degradation products. The structural elucidation showed that the tricycle moiety was unstable under thermal acidic and oxidative conditions since four degradation products possess an opened oxathiazepine ring. Then, a simple and fast HPLC-UV method was developed and validated for the determination of the degradation kinetic of BZN under acidic and oxidative conditions. The method was linear in the 5-100 μg mL(-1) concentration range with a good precision (RSD=2.2% and 2.7% for the repeatability and the intermediate precision, respectively) and a bias which never exceeded 1.6%, whatever the quality control level. With regards to the BZN concentration, a first-order degradation process was determined, with t(1/2)=703 h and 1140 h, under oxidative and acidic conditions, respectively.

  11. The contribution of mediated oxidation mechanisms in the electrolytic degradation of cyanuric acid using diamond anodes.

    PubMed

    Bensalah, Nasr; Dbira, Sondos; Bedoui, Ahmed

    2016-07-01

    In this work, the contribution of mediated oxidation mechanisms in the electrolytic degradation of cyanuric acid using boron-doped diamond (BDD) anodes was investigated in different electrolytes. A complete mineralization of cyanuric acid was obtained in NaCl; however lower degrees of mineralization of 70% and 40% were obtained in Na2SO4 and NaClO4, respectively. This can be explained by the nature of the oxidants electrogenerated in each electrolyte. It is clear that the contribution of active chlorine (Cl2, HClO, ClO(-)) electrogenerated from oxidation of chlorides on BDD is much more important in the electrolytic degradation of cyanuric acid than the persulfate and hydroxyl radicals produced by electro-oxidation of sulfate and water on BDD anodes. This could be explained by the high affinity of active chlorine towards nitrogen compounds. No organic intermediates were detected during the electrolytic degradation of cyanuric acid in any the electrolytes, which can be explained by their immediate depletion by hydroxyl radicals produced on the BDD surface. Nitrates and ammonium were the final products of electrolytic degradation of cyanuric acid on BDD anodes in all electrolytes. In addition, small amounts of chloramines were formed in the chloride medium. Low current density (≤10mA/cm(2)) and neutral medium (pH in the range 6-9) should be used for high efficiency electrolytic degradation and negligible formation of hazardous chlorate and perchlorate. PMID:27372125

  12. Fumaric acid production by fermentation

    PubMed Central

    Roa Engel, Carol A.; Zijlmans, Tiemen W.; van Gulik, Walter M.; van der Wielen, Luuk A. M.

    2008-01-01

    The potential of fumaric acid as a raw material in the polymer industry and the increment of cost of petroleum-based fumaric acid raises interest in fermentation processes for production of this compound from renewable resources. Although the chemical process yields 112% w/w fumaric acid from maleic anhydride and the fermentation process yields only 85% w/w from glucose, the latter raw material is three times cheaper. Besides, the fermentation fixes CO2. Production of fumaric acid by Rhizopus species and the involved metabolic pathways are reviewed. Submerged fermentation systems coupled with product recovery techniques seem to have achieved economically attractive yields and productivities. Future prospects for improvement of fumaric acid production include metabolic engineering approaches to achieve low pH fermentations. PMID:18214471

  13. Adverse effects of air pollutants on wood products and a method for preventing resulting degradation

    SciTech Connect

    Chao, W.Y.

    1992-01-01

    A study of wood surface in hostile environments was undertaken to elucidate the degradation mechanism and develop a method to protect wood in outdoor applications. In this investigation, wood was exposed to SO[sub 2] and NO[sub 2] in the presence and absence of ultraviolet light for up to 4 weeks. The effect of the simulated acid rain on wood with and without an epoxy film was evaluated by intermittent spraying of the wood with either sulfuric, nitric acid or water and irradiated with and without the xenon light in a weatherometer for up to 8 weeks. The surface properties of degraded wood and protective epoxy films were analyzed. UV light changed the wood color. The samples lost weight and generated water-soluble degradation products after the photoirradiation. Sulfur dioxide lighted the wood color; nitrogen dioxide changed wood color to brown. Wood increased its weight during the exposure of SO[sub 2] and NO[sub 2], however, the presence of such gases triggered photo-induced degradation. Lignin was degraded and carbonyl groups were formed at irradiated wood. Sulfur and nitrogen dioxides reduced the intensity of carbonyl groups due to degradative hydrolysis. Water-soluble products were derived from polysaccharides and lignin, nitric acid, sulfuric acid and its dissociated ions. During the simulated acidic weathering, xenon light changed the wood color. The color change rate of earlywood was greater than latewood. The presence of acids and water facilitated the wood degradation, and eventually caused leaching. The primary photodegradation phenomena of lignin was confirmed by the FTIR and UV analyses of the irradiated samples. Transparent anhydride-cured epoxy films partially protected wood against the acidic degradation and photoirradiation. Epoxy film cracked, yellowed and had O-ring shapes cavities after the exposure. Salol-added film provided the best protection for wood, followed by a film without an UV stabilizer and Tinuvin 770-added film last.

  14. Degradation products of cyanidin glycosides from tart cherries and their bioactivities.

    PubMed

    Seeram, N P; Bourquin, L D; Nair, M G

    2001-10-01

    The bioactive anthocyanins present in tart cherries, Prunus cerasus L. (Rosaceae) cv. Balaton, are cyanidin 3-glucosylrutinoside (1), cyanidin 3-rutinoside (2), and cyanidin 3-glucoside (3). Cyanidin (4) is the major anthocyanidin in tart cherries. In our continued evaluation of the in vivo and in vitro efficacy of these anthocyanins to prevent inflammation and colon cancer, we have added these compounds to McCoy's 5A medium in an effort to identify their degradation products during in vitro cell culture studies. This resulted in the isolation and characterization of protocatechuic acid (5), the predominant degradation product. In addition, 2,4-dihydroxybenzoic acid (6) and 2,4,6-trihydroxybenzoic acid (7) were identified as degradation products. However, these degradation products were not quantified. Compounds 5-7 were also identified as degradation products when anthocyanins were subjected to varying pH and thermal conditions. In cyclooxygenase (COX)-I and -II enzyme inhibitory assays, compounds 5-7 did not show significant activities when compared to the NSAIDs Naproxen, Celebrex, and Vioxx, or Ibuprofen, at 50 microM concentrations. However, at a test concentration of 50 microM, the antioxidant activity of protocatechuic acid (5) was comparable to those of the commercial antioxidants tert-butylhydroquinone (TBHQ), butylated hydroxytoluene (BHT), and butylated hydroxyanisole (BHA), and superior to that of vitamin E at 10 microM concentrations. PMID:11600045

  15. Genome Sequence Analysis of the Naphthenic Acid Degrading and Metal Resistant Bacterium Cupriavidus gilardii CR3

    PubMed Central

    Xiao, Jingfa; Hao, Lirui; Crowley, David E.; Zhang, Zhewen; Yu, Jun; Huang, Ning; Huo, Mingxin; Wu, Jiayan

    2015-01-01

    Cupriavidus sp. are generally heavy metal tolerant bacteria with the ability to degrade a variety of aromatic hydrocarbon compounds, although the degradation pathways and substrate versatilities remain largely unknown. Here we studied the bacterium Cupriavidus gilardii strain CR3, which was isolated from a natural asphalt deposit, and which was shown to utilize naphthenic acids as a sole carbon source. Genome sequencing of C. gilardii CR3 was carried out to elucidate possible mechanisms for the naphthenic acid biodegradation. The genome of C. gilardii CR3 was composed of two circular chromosomes chr1 and chr2 of respectively 3,539,530 bp and 2,039,213 bp in size. The genome for strain CR3 encoded 4,502 putative protein-coding genes, 59 tRNA genes, and many other non-coding genes. Many genes were associated with xenobiotic biodegradation and metal resistance functions. Pathway prediction for degradation of cyclohexanecarboxylic acid, a representative naphthenic acid, suggested that naphthenic acid undergoes initial ring-cleavage, after which the ring fission products can be degraded via several plausible degradation pathways including a mechanism similar to that used for fatty acid oxidation. The final metabolic products of these pathways are unstable or volatile compounds that were not toxic to CR3. Strain CR3 was also shown to have tolerance to at least 10 heavy metals, which was mainly achieved by self-detoxification through ion efflux, metal-complexation and metal-reduction, and a powerful DNA self-repair mechanism. Our genomic analysis suggests that CR3 is well adapted to survive the harsh environment in natural asphalts containing naphthenic acids and high concentrations of heavy metals. PMID:26301592

  16. Genome Sequence Analysis of the Naphthenic Acid Degrading and Metal Resistant Bacterium Cupriavidus gilardii CR3.

    PubMed

    Wang, Xiaoyu; Chen, Meili; Xiao, Jingfa; Hao, Lirui; Crowley, David E; Zhang, Zhewen; Yu, Jun; Huang, Ning; Huo, Mingxin; Wu, Jiayan

    2015-01-01

    Cupriavidus sp. are generally heavy metal tolerant bacteria with the ability to degrade a variety of aromatic hydrocarbon compounds, although the degradation pathways and substrate versatilities remain largely unknown. Here we studied the bacterium Cupriavidus gilardii strain CR3, which was isolated from a natural asphalt deposit, and which was shown to utilize naphthenic acids as a sole carbon source. Genome sequencing of C. gilardii CR3 was carried out to elucidate possible mechanisms for the naphthenic acid biodegradation. The genome of C. gilardii CR3 was composed of two circular chromosomes chr1 and chr2 of respectively 3,539,530 bp and 2,039,213 bp in size. The genome for strain CR3 encoded 4,502 putative protein-coding genes, 59 tRNA genes, and many other non-coding genes. Many genes were associated with xenobiotic biodegradation and metal resistance functions. Pathway prediction for degradation of cyclohexanecarboxylic acid, a representative naphthenic acid, suggested that naphthenic acid undergoes initial ring-cleavage, after which the ring fission products can be degraded via several plausible degradation pathways including a mechanism similar to that used for fatty acid oxidation. The final metabolic products of these pathways are unstable or volatile compounds that were not toxic to CR3. Strain CR3 was also shown to have tolerance to at least 10 heavy metals, which was mainly achieved by self-detoxification through ion efflux, metal-complexation and metal-reduction, and a powerful DNA self-repair mechanism. Our genomic analysis suggests that CR3 is well adapted to survive the harsh environment in natural asphalts containing naphthenic acids and high concentrations of heavy metals. PMID:26301592

  17. Degradation of extracellular matrix and its components by hypobromous acid

    PubMed Central

    Rees, Martin D.; McNiven, Tane N.; Davies, Michael J.

    2006-01-01

    EPO (eosinophil peroxidase) and MPO (myeloperoxidase) are highly basic haem enzymes that can catalyse the production of HOBr (hypobromous acid). They are released extracellularly by activated leucocytes and their binding to the polyanionic glycosa-minoglycan components of extracellular matrix (proteoglycans and hyaluronan) may localize the production of HOBr to these materials. It is shown in the present paper that the reaction of HOBr with glycosaminoglycans (heparan sulfate, heparin, chondroitin sulfate and hyaluronan) generates polymer-derived N-bromo derivatives (bromamines, dibromamines, N-bromosulfon-amides and bromamides). Decomposition of these species, which can occur spontaneously and/or via one-electron reduction by low-valent transition metal ions (Cu+ and Fe2+), results in polymer fragmentation and modification. One-electron reduction of the N-bromo derivatives generates radicals that have been detected by EPR spin trapping. The species detected are consistent with metal ion-dependent polymer fragmentation and modification being initiated by the formation of nitrogen-centred (aminyl, N-bromoaminyl, sulfonamidyl and amidyl) radicals. Previous studies have shown that the reaction of HOBr with proteins generates N-bromo derivatives and results in fragmentation of the polypeptide backbone. The reaction of HOBr with extracellular matrix synthesized by smooth muscle cells in vitro induces the release of carbohydrate and protein components in a time-dependent manner, which is consistent with fragmentation of these materials via the formation of N-bromo derivatives. The degradation of extracellular matrix glycosaminoglycans and proteins by HOBr may contribute to tissue damage associated with inflammatory diseases such as asthma. PMID:17014424

  18. Microbial production of lactic acid.

    PubMed

    Eiteman, Mark A; Ramalingam, Subramanian

    2015-05-01

    Lactic acid is an important commodity chemical having a wide range of applications. Microbial production effectively competes with chemical synthesis methods because biochemical synthesis permits the generation of either one of the two enantiomers with high optical purity at high yield and titer, a result which is particularly beneficial for the production of poly(lactic acid) polymers having specific properties. The commercial viability of microbial lactic acid production relies on utilization of inexpensive carbon substrates derived from agricultural or waste resources. Therefore, optimal lactic acid formation requires an understanding and engineering of both the competing pathways involved in carbohydrate metabolism, as well as pathways leading to potential by-products which both affect product yield. Recent research leverages those biochemical pathways, while researchers also continue to seek strains with improved tolerance and ability to perform under desirable industrial conditions, for example, of pH and temperature.

  19. Characterization of the Complete Uric Acid Degradation Pathway in the Fungal Pathogen Cryptococcus neoformans

    PubMed Central

    Lee, I. Russel; Yang, Liting; Sebetso, Gaseene; Allen, Rebecca; Doan, Thi H. N.; Blundell, Ross; Lui, Edmund Y. L.; Morrow, Carl A.; Fraser, James A.

    2013-01-01

    Degradation of purines to uric acid is generally conserved among organisms, however, the end product of uric acid degradation varies from species to species depending on the presence of active catabolic enzymes. In humans, most higher primates and birds, the urate oxidase gene is non-functional and hence uric acid is not further broken down. Uric acid in human blood plasma serves as an antioxidant and an immune enhancer; conversely, excessive amounts cause the common affliction gout. In contrast, uric acid is completely degraded to ammonia in most fungi. Currently, relatively little is known about uric acid catabolism in the fungal pathogen Cryptococcus neoformans even though this yeast is commonly isolated from uric acid-rich pigeon guano. In addition, uric acid utilization enhances the production of the cryptococcal virulence factors capsule and urease, and may potentially modulate the host immune response during infection. Based on these important observations, we employed both Agrobacterium-mediated insertional mutagenesis and bioinformatics to predict all the uric acid catabolic enzyme-encoding genes in the H99 genome. The candidate C. neoformans uric acid catabolic genes identified were named: URO1 (urate oxidase), URO2 (HIU hydrolase), URO3 (OHCU decarboxylase), DAL1 (allantoinase), DAL2,3,3 (allantoicase-ureidoglycolate hydrolase fusion protein), and URE1 (urease). All six ORFs were then deleted via homologous recombination; assaying of the deletion mutants' ability to assimilate uric acid and its pathway intermediates as the sole nitrogen source validated their enzymatic functions. While Uro1, Uro2, Uro3, Dal1 and Dal2,3,3 were demonstrated to be dispensable for virulence, the significance of using a modified animal model system of cryptococcosis for improved mimicking of human pathogenicity is discussed. PMID:23667704

  20. Peptide nucleic acid films and capsules: assembly and enzymatic degradation.

    PubMed

    Becker, Alisa L; Johnston, Angus P R; Caruso, Frank

    2010-05-14

    Sequence-directed hybridization of nucleic acids provides a high level of control for the bottom-up assembly of nanostructured materials. Altering the DNA sequence affords control and versatility over the film structure, but is limited by the chemical and physical properties of DNA. Here, we use DNA analogues, peptide nucleic acids (PNAs), to introduce new properties to multilayered thin films and retain the advantages of sequence-directed assembly. Thin films, formed by the layer-by-layer (LbL) assembly of PNA strands, were assembled from short PNA sequences on planar and colloidal substrates. In the case of PNA-coated particles, hollow capsules were obtained following removal of the sacrificial particle template. The PNA films were stable to both nuclease and protease degradation, and the nuclease degradation rate could be tuned by varying the amount of DNA incorporated into the films. These thin films may find use in biomedical applications.

  1. Poly(L-lactide)-degrading enzyme production by Actinomadura keratinilytica T16-1 in 3 L airlift bioreactor and its degradation ability for biological recycle.

    PubMed

    Sukkhum, Sukhumaporn; Tokuyama, Shinji; Kitpreechavanich, Vichien

    2012-01-01

    The optimal physical factors affecting enzyme production in an airlift fermenter have not been studied so far. Therefore, the physical parameters such as aeration rate, pH, and temperature affecting PLA-degrading enzyme production by Actinomadura keratinilytica strain T16-1 in a 3 l airlift fermenter were investigated. The response surface methodology (RSM) was used to optimize PLA-degrading enzyme production by implementing the central composite design. The optimal conditions for higher production of PLA-degrading enzyme were aeration rate of 0.43 vvm, pH of 6.85, and temperature at 46° C. Under these conditions, the model predicted a PLA-degrading activity of 254 U/ml. Verification of the optimization showed that PLA-degrading enzyme production of 257 U/ml was observed after 3 days cultivation under the optimal conditions in a 3 l airlift fermenter. The production under the optimized condition in the airlift fermenter was higher than un-optimized condition by 1.7 folds and 12 folds with un-optimized medium or condition in shake flasks. This is the first report on the optimization of environmental conditions for improvement of PLA-degrading enzyme production in a 3 l airlift fermenter by using a statistical analysis method. Moreover, the crude PLA-degrading enzyme could be adsorbed to the substrate and degraded PLA powder to produce lactic acid as degradation products. Therefore, this incident indicates that PLA-degrading enzyme produced by Actinomadura keratinilytica NBRC 104111 strain T16-1 has a potential to degrade PLA to lactic acid as a monomer and can be used for the recycle of PLA polymer. PMID:22297224

  2. Degradation Kinetics and Mechanism of Lithospermic Acid under Low Oxygen Condition Using Quantitative 1H NMR with HPLC-MS

    PubMed Central

    Pan, Jianyang; Gong, Xingchu; Qu, Haibin

    2016-01-01

    A novel quantitative 1H NMR (Q-NMR) combined with HPLC-MS method has been proposed for investigating the degradation process of traditional Chinese medicine (TCM) components. Through this method, in-situ monitoring of dynamics degradation process of lithospermic acid (LA), one of the popular polyphenolic acids in TCM, was realized under low oxygen condition. Additionally, this methodology was proved to be simple, rapid and specific. Degradation kinetic runs have been carried out to systematically investigate the effects of two key environmental factors, initial pH values and temperatures. Eight main degradation products of LA were detected, seven of which were tentatively structural elucidated with the help of both NMR and LC-MS in this work and salvianolic acid A (Sal A) was the primary degradation product of LA. A possible degradation pathway of LA was proposed, subsequently. The results showed that the degradation of LA followed pseudo-first-order kinetics. The apparent degradation kinetic constants increased as the initial pH value of the phosphate buffer increased. Under the given conditions, the rate constants of overall degradation as a function of temperature obeyed the Arrhenius equation. Our results proved that the Q-NMR combined with HPLC-MS method can be one of the most promising techniques for investigating degradation process of active components in TCM. PMID:27776128

  3. Degradation of ascorbic acid and potassium sorbate by different Lactobacillus species isolated from packed green olives.

    PubMed

    Montaño, Alfredo; Sánchez, Antonio Higinio; Casado, Francisco Javier; Beato, Víctor Manuel; de Castro, Antonio

    2013-05-01

    The aim of this research was to ascertain the lactic acid bacteria responsible for the degradation of ascorbic acid and/or potassium sorbate, isolated from packed green olives where these additives had diminished. A total of 14 isolates were recovered from samples of different green olive containers. According to partial sequencing of the 16S rRNA coding gene, Lactobacillus parafarraginis, Lactobacillus rapi, Lactobacillus pentosus, Lactobacillus paracollinoides, and Pediococcus ethanolidurans were identified. With the exception of L. pentosus and L. paracollinoides, the other species had not been mentioned in table olives before this study. Only three of the 14 isolates metabolized ascorbic acid in MRS broth, and the products from ascorbic acid in modified MRS broth without carbon sources were acetic and lactic acids. Except for the two L. rapi and the two P. ethanolidurans strains, the remaining 10 isolates depleted potassium sorbate added into MRS broth to some extent. The product generated by three of these strains was confirmed to be trans-4-hexenoic acid. The degradation of ascorbate or sorbate by lactic acid bacteria should be taken into account when these additives are used in food products where this group of bacteria may be present. PMID:23498172

  4. Oxidative degradation of triclosan by potassium permanganate: Kinetics, degradation products, reaction mechanism, and toxicity evaluation.

    PubMed

    Chen, Jing; Qu, Ruijuan; Pan, Xiaoxue; Wang, Zunyao

    2016-10-15

    In this study, we systematically investigated the potential applicability of potassium permanganate for removal of triclosan (TCS) in water treatment. A series of kinetic experiments were carried out to study the influence of various factors, including the pH, oxidant doses, temperature, and presence of typical anions (Cl(-), SO4(2-), NO3(-)), humic acid (HA), and fulvic acid (FA) on triclosan removal. The optimal reaction conditions were: pH = 8.0, [TCS]0:[KMnO4]0 = 1:2.5, and T = 25 °C, where 20 mg/L of TCS could be completely degraded in 120 s. However, the rate of TCS (20 μg/L) oxidation by KMnO4 ([TCS]0:[KMnO4]0 = 1:2.5) was 1.64 × 10(-3) mg L(-1)·h(-1), lower than that at an initial concentration of 20 mg/L (2.24 × 10(3) mg L(-1)·h(-1)). A total of eleven products were detected by liquid chromatography-quadrupole-time-of-flight-mass spectrometry (LC-Q-TOF-MS) analysis, including phenol and its derivatives, benzoquinone, an organic acid, and aldehyde. Two main reaction pathways involving CO bond cleavage (-C(8)O(7)-) and benzene ring opening (in the less chlorinated benzene ring) were proposed, and were further confirmed based on frontier electron density calculations and point charges. Furthermore, the changes in the toxicity of the reaction solution during TCS oxidation by KMnO4 were evaluated by using both the luminescent bacteria Photobacterium phosphoreum and the water flea Daphnia magna. The toxicity of 20 mg/L triclosan to D. magna and P. phosphoreum after 60 min was reduced by 95.2% and 43.0%, respectively. Phenol and 1,4-benzoquinone, the two representative degradation products formed during permanganate oxidation, would yield low concentrations of DBPs (STHMFP, 20.99-278.97 μg/mg; SHAAFP, 7.86 × 10(-4)-45.77 μg/mg) after chlorination and chloramination. Overall, KMnO4 can be used as an effective oxidizing agent for TCS removal in water and wastewater treatment.

  5. Oxidative degradation of triclosan by potassium permanganate: Kinetics, degradation products, reaction mechanism, and toxicity evaluation.

    PubMed

    Chen, Jing; Qu, Ruijuan; Pan, Xiaoxue; Wang, Zunyao

    2016-10-15

    In this study, we systematically investigated the potential applicability of potassium permanganate for removal of triclosan (TCS) in water treatment. A series of kinetic experiments were carried out to study the influence of various factors, including the pH, oxidant doses, temperature, and presence of typical anions (Cl(-), SO4(2-), NO3(-)), humic acid (HA), and fulvic acid (FA) on triclosan removal. The optimal reaction conditions were: pH = 8.0, [TCS]0:[KMnO4]0 = 1:2.5, and T = 25 °C, where 20 mg/L of TCS could be completely degraded in 120 s. However, the rate of TCS (20 μg/L) oxidation by KMnO4 ([TCS]0:[KMnO4]0 = 1:2.5) was 1.64 × 10(-3) mg L(-1)·h(-1), lower than that at an initial concentration of 20 mg/L (2.24 × 10(3) mg L(-1)·h(-1)). A total of eleven products were detected by liquid chromatography-quadrupole-time-of-flight-mass spectrometry (LC-Q-TOF-MS) analysis, including phenol and its derivatives, benzoquinone, an organic acid, and aldehyde. Two main reaction pathways involving CO bond cleavage (-C(8)O(7)-) and benzene ring opening (in the less chlorinated benzene ring) were proposed, and were further confirmed based on frontier electron density calculations and point charges. Furthermore, the changes in the toxicity of the reaction solution during TCS oxidation by KMnO4 were evaluated by using both the luminescent bacteria Photobacterium phosphoreum and the water flea Daphnia magna. The toxicity of 20 mg/L triclosan to D. magna and P. phosphoreum after 60 min was reduced by 95.2% and 43.0%, respectively. Phenol and 1,4-benzoquinone, the two representative degradation products formed during permanganate oxidation, would yield low concentrations of DBPs (STHMFP, 20.99-278.97 μg/mg; SHAAFP, 7.86 × 10(-4)-45.77 μg/mg) after chlorination and chloramination. Overall, KMnO4 can be used as an effective oxidizing agent for TCS removal in water and wastewater treatment. PMID:27459151

  6. The sources, fate, and toxicity of chemical warfare agent degradation products.

    PubMed Central

    Munro, N B; Talmage, S S; Griffin, G D; Waters, L C; Watson, A P; King, J F; Hauschild, V

    1999-01-01

    We include in this review an assessment of the formation, environmental fate, and mammalian and ecotoxicity of CW agent degradation products relevant to environmental and occupational health. These parent CW agents include several vesicants: sulfur mustards [undistilled sulfur mustard (H), sulfur mustard (HD), and an HD/agent T mixture (HT)]; nitrogen mustards [ethylbis(2-chloroethyl)amine (HN1), methylbis(2-chloroethyl)amine (HN2), tris(2-chloroethyl)amine (HN3)], and Lewisite; four nerve agents (O-ethyl S-[2-(diisopropylamino)ethyl] methylphosphonothioate (VX), tabun (GA), sarin (GB), and soman (GD)); and the blood agent cyanogen chloride. The degradation processes considered here include hydrolysis, microbial degradation, oxidation, and photolysis. We also briefly address decontamination but not combustion processes. Because CW agents are generally not considered very persistent, certain degradation products of significant persistence, even those that are not particularly toxic, may indicate previous CW agent presence or that degradation has occurred. Of those products for which there are data on both environmental fate and toxicity, only a few are both environmentally persistent and highly toxic. Major degradation products estimated to be of significant persistence (weeks to years) include thiodiglycol for HD; Lewisite oxide for Lewisite; and ethyl methyl phosphonic acid, methyl phosphonic acid, and possibly S-(2-diisopropylaminoethyl) methylphosphonothioic acid (EA 2192) for VX. Methyl phosphonic acid is also the ultimate hydrolysis product of both GB and GD. The GB product, isopropyl methylphosphonic acid, and a closely related contaminant of GB, diisopropyl methylphosphonate, are also persistent. Of all of these compounds, only Lewisite oxide and EA 2192 possess high mammalian toxicity. Unlike other CW agents, sulfur mustard agents (e.g., HD) are somewhat persistent; therefore, sites or conditions involving potential HD contamination should include an

  7. Comparative Genomics of Syntrophic Branched-Chain Fatty Acid Degrading Bacteria

    PubMed Central

    Narihiro, Takashi; Nobu, Masaru K.; Tamaki, Hideyuki; Kamagata, Yoichi; Sekiguchi, Yuji; Liu, Wen-Tso

    2016-01-01

    The syntrophic degradation of branched-chain fatty acids (BCFAs) such as 2-methylbutyrate and isobutyrate is an essential step in the production of methane from proteins/amino acids in anaerobic ecosystems. While a few syntrophic BCFA-degrading bacteria have been isolated, their metabolic pathways in BCFA and short-chain fatty acid (SCFA) degradation as well as energy conservation systems remain unclear. In an attempt to identify these pathways, we herein performed comparative genomics of three syntrophic bacteria: 2-methylbutyrate-degrading “Syntrophomonas wolfei subsp. methylbutyratica” strain JCM 14075T (=4J5T), isobutyrate-degrading Syntrophothermus lipocalidus strain TGB-C1T, and non-BCFA-metabolizing S. wolfei subsp. wolfei strain GöttingenT. We demonstrated that 4J5 and TGB-C1 both encode multiple genes/gene clusters involved in β-oxidation, as observed in the Göttingen genome, which has multiple copies of genes associated with butyrate degradation. The 4J5 genome possesses phylogenetically distinct β-oxidation genes, which may be involved in 2-methylbutyrate degradation. In addition, these Syntrophomonadaceae strains harbor various hydrogen/formate generation systems (i.e., electron-bifurcating hydrogenase, formate dehydrogenase, and membrane-bound hydrogenase) and energy-conserving electron transport systems, including electron transfer flavoprotein (ETF)-linked acyl-CoA dehydrogenase, ETF-linked iron-sulfur binding reductase, ETF dehydrogenase (FixABCX), and flavin oxidoreductase-heterodisulfide reductase (Flox-Hdr). Unexpectedly, the TGB-C1 genome encodes a nitrogenase complex, which may function as an alternative H2 generation mechanism. These results suggest that the BCFA-degrading syntrophic strains 4J5 and TGB-C1 possess specific β-oxidation-related enzymes for BCFA oxidation as well as appropriate energy conservation systems to perform thermodynamically unfavorable syntrophic metabolism. PMID:27431485

  8. Degradation of 3-Phenoxybenzoic Acid by a Bacillus sp

    PubMed Central

    Chen, Shaohua; Hu, Wei; Xiao, Ying; Deng, Yinyue; Jia, Jianwen; Hu, Meiying

    2012-01-01

    3-Phenoxybenzoic acid (3-PBA) is of great environmental concern with regards to endocrine disrupting activity and widespread occurrence in water and soil, yet little is known about microbial degradation in contaminated regions. We report here that a new bacterial strain isolated from soil, designated DG-02, was shown to degrade 95.6% of 50 mg·L−1 3-PBA within 72 h in mineral salt medium (MSM). Strain DG-02 was identified as Bacillus sp. based on the morphology, physio-biochemical tests and 16S rRNA sequence. The optimum conditions for 3-PBA degradation were determined to be 30.9°C and pH 7.7 using response surface methodology (RSM). The isolate converted 3-PBA to produce 3-(2-methoxyphenoxy) benzoic acid, protocatechuate, phenol, and 3,4-dihydroxy phenol, and subsequently transformed these compounds with a qmax, Ks and Ki of 0.8615 h−1, 626.7842 mg·L−1 and 6.7586 mg·L−1, respectively. A novel microbial metabolic pathway for 3-PBA was proposed on the basis of these metabolites. Inoculation of strain DG-02 resulted in a higher degradation rate on 3-PBA than that observed in the non-inoculated soil. Moreover, the degradation process followed the first-order kinetics, and the half-life (t1/2) for 3-PBA was greatly reduced as compared to the non-inoculated control. This study highlights an important potential application of strain DG-02 for the in situ bioremediation of 3-PBA contaminated environments. PMID:23226289

  9. Degradation of the synthetic dye amaranth by the fungus Bjerkandera adusta Dec 1: inference of the degradation pathway from an analysis of decolorized products.

    PubMed

    Gomi, Nichina; Yoshida, Shuji; Matsumoto, Kazutsugu; Okudomi, Masayuki; Konno, Hiroki; Hisabori, Toru; Sugano, Yasushi

    2011-11-01

    We examined the degradation of amaranth, a representative azo dye, by Bjerkandera adusta Dec 1. The degradation products were analyzed by high performance liquid chromatography (HPLC), visible absorbance, and electrospray ionization time-of-flight mass spectroscopy (ESI-TOF-MS). At the primary culture stage (3 days), the probable reaction intermediates were 1-aminonaphthalene-2,3,6-triol, 4-(hydroxyamino) naphthalene-1-ol, and 2-hydroxy-3-[2-(4-sulfophenyl) hydrazinyl] benzenesulfonic acid. After 10 days, the reaction products detected were 4-nitrophenol, phenol, 2-hydroxy-3-nitrobenzenesulfonic acid, 4-nitrobenzene sulfonic acid, and 3,4'-disulfonyl azo benzene, suggesting that no aromatic amines were created. Manganese-dependent peroxidase activity increased sharply after 3 days culture. Based on these results, we herein propose, for the first time, a degradation pathway for amaranth. Our results suggest that Dec 1 degrades amaranth via the combined activities of peroxidase and hydrolase and reductase action.

  10. [Photocatalytic Degradation of Perfluorooctanoic Acid by Pd-TiO2 Photocatalyst].

    PubMed

    Liu, Qing; Yu, Ze-bin; Zhang, Rui-han; Li, Ming-jie; Chen, Ying; Wang, Li; Kuang, Yu; Zhang, Bo; Zhu, You-hui

    2015-06-01

    Perfluorooctanoic acid (PFOA) is a new persistent organic pollutant which has got global concern for its wide distribution, high bioaccumulation and strong biological toxicity. In present study, the photocatalytic degradation of PFOA using palladium doped TiO2 (Pd-TiO2) prepared by chemical reduction method was investigated. The photocatalysts were characterized by XRD, FESEM and UV-vis DRS and were used for PFOA degradation under 365 nm UV irradiation. The results indicated that the grain size of TiO2 was smaller while the specific surface area increased and the absorption of ultraviolet light also enhanced after using chemical reduction method, but all these changes had no influence on PFOA degradation. However, the degradation was significantly enhanced because of the deposition of Pd, the fluoride concentration of PFOA was 6.62 mg x L(-1) after 7 h irradiation which was 7.3 times higher than that of TiO2 (P25). Experiments with the addition of trapping agent and nitrogen indicated that *OH played an important role in PFOA degradation while the presence of O2 accelerated the degradation. The main intermediate products of photocatalytic degradation of PFOA were authenticated by an ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry systems (UPLC-QTOF-MS). The probable photocatalytic degradation mechanism involves h+ attacking the carboxyl of PFOA and resulting in decarboxylation. The produced *CnF(2n +1) was oxidized by *OH underwent defluorinetion to form shorter-chain perfluorinated carboxylic acids. The significant enhancement of PFOA degradation can be ascribed to the palladium deposits, acting as electron traps on the Pd-TiO2 surface, which facilitated the transfer of photogenerated electrons and retarded the accumulation of electrons. PMID:26387318

  11. [Photocatalytic Degradation of Perfluorooctanoic Acid by Pd-TiO2 Photocatalyst].

    PubMed

    Liu, Qing; Yu, Ze-bin; Zhang, Rui-han; Li, Ming-jie; Chen, Ying; Wang, Li; Kuang, Yu; Zhang, Bo; Zhu, You-hui

    2015-06-01

    Perfluorooctanoic acid (PFOA) is a new persistent organic pollutant which has got global concern for its wide distribution, high bioaccumulation and strong biological toxicity. In present study, the photocatalytic degradation of PFOA using palladium doped TiO2 (Pd-TiO2) prepared by chemical reduction method was investigated. The photocatalysts were characterized by XRD, FESEM and UV-vis DRS and were used for PFOA degradation under 365 nm UV irradiation. The results indicated that the grain size of TiO2 was smaller while the specific surface area increased and the absorption of ultraviolet light also enhanced after using chemical reduction method, but all these changes had no influence on PFOA degradation. However, the degradation was significantly enhanced because of the deposition of Pd, the fluoride concentration of PFOA was 6.62 mg x L(-1) after 7 h irradiation which was 7.3 times higher than that of TiO2 (P25). Experiments with the addition of trapping agent and nitrogen indicated that *OH played an important role in PFOA degradation while the presence of O2 accelerated the degradation. The main intermediate products of photocatalytic degradation of PFOA were authenticated by an ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry systems (UPLC-QTOF-MS). The probable photocatalytic degradation mechanism involves h+ attacking the carboxyl of PFOA and resulting in decarboxylation. The produced *CnF(2n +1) was oxidized by *OH underwent defluorinetion to form shorter-chain perfluorinated carboxylic acids. The significant enhancement of PFOA degradation can be ascribed to the palladium deposits, acting as electron traps on the Pd-TiO2 surface, which facilitated the transfer of photogenerated electrons and retarded the accumulation of electrons.

  12. Biotechnological production of citric acid

    PubMed Central

    Max, Belén; Salgado, José Manuel; Rodríguez, Noelia; Cortés, Sandra; Converti, Attilio; Domínguez, José Manuel

    2010-01-01

    This work provides a review about the biotechnological production of citric acid starting from the physicochemical properties and industrial applications, mainly in the food and pharmaceutical sectors. Several factors affecting citric acid fermentation are discussed, including carbon source, nitrogen and phosphate limitations, pH of culture medium, aeration, trace elements and morphology of the fungus. Special attention is paid to the fundamentals of biochemistry and accumulation of citric acid. Technologies employed at industrial scale such as surface or submerged cultures, mainly employing Aspergillus niger, and processes carried out with Yarrowia lipolytica, as well as the technology for recovering the product are also described. Finally, this review summarizes the use of orange peels and other by-products as feedstocks for the bioproduction of citric acid. PMID:24031566

  13. From ether to acid: A plausible degradation pathway of glycerol dialkyl glycerol tetraethers

    NASA Astrophysics Data System (ADS)

    Liu, Xiao-Lei; Birgel, Daniel; Elling, Felix J.; Sutton, Paul A.; Lipp, Julius S.; Zhu, Rong; Zhang, Chuanlun; Könneke, Martin; Peckmann, Jörn; Rowland, Steven J.; Summons, Roger E.; Hinrichs, Kai-Uwe

    2016-06-01

    Glycerol dialkyl glycerol tetraethers (GDGTs) are ubiquitous microbial lipids with extensive demonstrated and potential roles as paleoenvironmental proxies. Despite the great attention they receive, comparatively little is known regarding their diagenetic fate. Putative degradation products of GDGTs, identified as hydroxyl and carboxyl derivatives, were detected in lipid extracts of marine sediment, seep carbonate, hot spring sediment and cells of the marine thaumarchaeon Nitrosopumilus maritimus. The distribution of GDGT degradation products in environmental samples suggests that both biotic and abiotic processes act as sinks for GDGTs. More than a hundred newly recognized degradation products afford a view of the stepwise degradation of GDGT via (1) ether bond hydrolysis yielding hydroxyl isoprenoids, namely, GDGTol (glycerol dialkyl glycerol triether alcohol), GMGD (glycerol monobiphytanyl glycerol diether), GDD (glycerol dibiphytanol diether), GMM (glycerol monobiphytanol monoether) and bpdiol (biphytanic diol); (2) oxidation of isoprenoidal alcohols into corresponding carboxyl derivatives and (3) chain shortening to yield C39 and smaller isoprenoids. This plausible GDGT degradation pathway from glycerol ethers to isoprenoidal fatty acids provides the link to commonly detected head-to-head linked long chain isoprenoidal hydrocarbons in petroleum and sediment samples. The problematic C80 to C82 tetraacids that cause naphthenate deposits in some oil production facilities can be generated from H-shaped glycerol monoalkyl glycerol tetraethers (GMGTs) following the same process, as indicated by the distribution of related derivatives in hydrothermally influenced sediments.

  14. Mechanism driven structural elucidation of forced degradation products from hydrocortisone in solution.

    PubMed

    Zhang, Fa; Zhou, Jay; Shi, Yiqun; Tavlarakis, Panagiotis; Karaisz, Kenneth

    2016-09-01

    Hydrocortisone degradation products 1, 2, 3, and 4 along with hemiacetal derivatives 5, 6, 7, and 8 were observed through stressed hydrocortisone in solution. Their structures were identified based on HPLC-UV, HPLC-MS, and HPLC-HRMS (high resolution/high accuracy mass spectrometry) analyses as well as reaction mechanistic investigation and synthesis for structural confirmation. 1 and 2 are a pair of E/Z isomers and they were generated through acid catalyzed tautomerization/dehydration of hydrocortisone. Incorporation of water to 1 and 2 resulted in the formation of 3. We also discovered new degradation product 4 which was converted from 3 by oxidation. The degradation products were synthesized by stressing hydrocortisone under the optimized conditions and their structures were characterized by NMR ((1)H/(13)C, COSY, HMBC, HSQC, NOESY) and HRMS analyses. The degradation pathway of hydrocortisone is postulated.

  15. Mechanism driven structural elucidation of forced degradation products from hydrocortisone in solution.

    PubMed

    Zhang, Fa; Zhou, Jay; Shi, Yiqun; Tavlarakis, Panagiotis; Karaisz, Kenneth

    2016-09-01

    Hydrocortisone degradation products 1, 2, 3, and 4 along with hemiacetal derivatives 5, 6, 7, and 8 were observed through stressed hydrocortisone in solution. Their structures were identified based on HPLC-UV, HPLC-MS, and HPLC-HRMS (high resolution/high accuracy mass spectrometry) analyses as well as reaction mechanistic investigation and synthesis for structural confirmation. 1 and 2 are a pair of E/Z isomers and they were generated through acid catalyzed tautomerization/dehydration of hydrocortisone. Incorporation of water to 1 and 2 resulted in the formation of 3. We also discovered new degradation product 4 which was converted from 3 by oxidation. The degradation products were synthesized by stressing hydrocortisone under the optimized conditions and their structures were characterized by NMR ((1)H/(13)C, COSY, HMBC, HSQC, NOESY) and HRMS analyses. The degradation pathway of hydrocortisone is postulated. PMID:27328360

  16. Acetamide herbicides and their degradation products in ground water and surface water of the United States, 1993-2003

    USGS Publications Warehouse

    Scribner, Elisabeth A.; Dietze, Julie E.; Thurman, Michael

    2004-01-01

    During 1993 through 2003, the U.S. Geological Survey conducted a number of studies to investigate and document the occurrence, fate, and transport of acetamide herbicides and their degradation products in ground and surface water. As part of these studies, approximately 5,100 water samples were collected and analyzed for the acetamide parent herbicides acetochlor, alachlor, dimethenamid, flufenacet, and metolachlor and their degradation products ethanesulfonic acid, oxanilic acid, and sulfinyl acetic acid. During this period, various analytical methods were developed to detect and measure concentrations of acetamide herbicides and their degradation products in ground water and surface water. Results showed that the degradation products of acetamide herbicides in ground water were detected more frequently and occurred at higher concentrations than their parent compounds. Further study showed that the acetamide herbicides and their degradation products were detected more frequently in surface water than in ground water. In general, the parent compounds were detected at similar or greater frequencies than the degradation products in surface water. The developed methods and data were valuable for acquiring information about the occurrence, fate, and transport of the herbicides and their degradation products and the importance of analyzing for both parent compounds and their degradate products in water-quality studies.

  17. LC-MS/MS characterization of forced degradation products of zofenopril.

    PubMed

    Ramesh, Thippani; Nageswara Rao, Pothuraju; Nageswara Rao, Ramisetti

    2014-01-01

    A rapid, specific and reliable isocratic LC-MS/MS method has been developed and validated for the identification and characterization of stressed degradation products of Zofenopril. Zofenopril, an anti-hypertensive drug, was subjected to hydrolysis (acidic, alkaline and neutral), oxidation, photolysis and thermal stress, as per ICH-specified conditions. The drug showed extensive degradation under oxidative and base hydrolysis stress conditions. However, it was stable to thermal, acid, neutral and photolysis stress conditions. A total of 6 degradation products were observed and the chromatographic separation of the drug and its degradation products were achieved on Phenomenex (Luna) C18 (250mm×4.6mm, i.d., 5μm) column using 20mM ammonium acetate: acetonitrile (50:50, v/v) as a mobile phase. The degradation products were characterized by LC-MS/MS and its fragmentation pathways were proposed. The LC-MS method was validated with respect to specificity, linearity, accuracy and precision. No previous reports were found in the literature regarding the degradation behavior of zofenopril. PMID:24211724

  18. [Degradation kinetics of chlorogenic acid, cryptochlorogenic acid, and neochlorogenic acid at neutral and alkaline pH values].

    PubMed

    Zhu, Peng; Miao, Xiao-lei; Chen, Yong

    2016-01-01

    The degradation kinetics of chlorogenic acid (5-CQA), cryptochlorogenic acid (4-CQA), and neochlorogenic acid (3-CQA) in aqueous solution at 37 degrees C and different pH values (7.05, 7.96, 9.25) were investigated in the present work. The results indicated that 3-, 4- and 5-CQA tended to remain stable in acidic pH circumstance, and unstable in neutral and alkaline pH circumstance. With the increase of the alkalinity, the degradation of 3-, 4- and 5-CQA was increased leading to a less amount of total CQA and was satisfactorily described by the Weibull equation. Meanwhile, caffeic acid was not detected after the degradation of CQA. Moreover, the degradation of 3-CQA and 5-CQA tended to be converted to 4-CQA, and the degradation of 4-CQA tended to be converted to 3-CQA rather than 5-CQA. The comparison of the degradation kinetics parameters of 3-, 4- and 5-CQA at neutral and alkaline pH values showed that the orders of the rate constant (k) values were 4-CQA > 3-CQA > 5-CQA, while the orders of the degradation half life (t½) values were 4-CQA < 3-CQA < 5-CQA, indicating the orders of the stabilities of 3-, 4- and 5-CQA at 37 degrees C and neutral and alkaline pH values were 4-CQA < 3-CQA < 5-CQA. PMID:27405173

  19. Treatment of low level radioactive liquid waste containing appreciable concentration of TBP degraded products.

    PubMed

    Valsala, T P; Sonavane, M S; Kore, S G; Sonar, N L; De, Vaishali; Raghavendra, Y; Chattopadyaya, S; Dani, U; Kulkarni, Y; Changrani, R D

    2011-11-30

    The acidic and alkaline low level radioactive liquid waste (LLW) generated during the concentration of high level radioactive liquid waste (HLW) prior to vitrification and ion exchange treatment of intermediate level radioactive liquid waste (ILW), respectively are decontaminated by chemical co-precipitation before discharge to the environment. LLW stream generated from the ion exchange treatment of ILW contained high concentrations of carbonates, tributyl phosphate (TBP) degraded products and problematic radio nuclides like (106)Ru and (99)Tc. Presence of TBP degraded products was interfering with the co-precipitation process. In view of this a modified chemical treatment scheme was formulated for the treatment of this waste stream. By mixing the acidic LLW and alkaline LLW, the carbonates in the alkaline LLW were destroyed and the TBP degraded products got separated as a layer at the top of the vessel. By making use of the modified co-precipitation process the effluent stream (1-2 μCi/L) became dischargeable to the environment after appropriate dilution. Based on the lab scale studies about 250 m(3) of LLW was treated in the plant. The higher activity of the TBP degraded products separated was due to short lived (90)Y isotope. The cement waste product prepared using the TBP degraded product was having good chemical durability and compressive strength.

  20. Dependence of transformation product formation on pH during photolytic and photocatalytic degradation of ciprofloxacin.

    PubMed

    Salma, Alaa; Thoröe-Boveleth, Sven; Schmidt, Torsten C; Tuerk, Jochen

    2016-08-01

    Ciprofloxacin (CIP) is a broad-spectrum antibiotic with five pH dependent species in aqueous medium, which makes its degradation behavior difficult to predict. For the identification of transformation products and prediction of degradation mechanisms, a new experimental concept making use of isotopically labeled compounds together with high resolution mass spectrometry was successfully established. The utilization of deuterated ciprofloxacin (CIP-d8) facilitated the prediction of three different degradation pathways and the corresponding degradation products, four of which were identified for the first time. Moreover, two molecular structures of previously reported transformation products were revised according to the mass spectra and product ion spectra of the deuterated transformation products. Altogether, 18 transformation products have been identified during the photolytic and photocatalytic reactions at different pH values (3, 5, 7 and 9). In this work the influence of pH on both reaction kinetics and degradation mechanism was investigated for direct ultraviolet photolysis (UV-C irradiation) and photocatalysis (TiO2/UV-C). It could be shown that the removal rates strongly depended on pH with highest removal rates at pH 9. A comparison with those at pH 3 clearly indicated that under acidic conditions ciprofloxacin cannot be easily excited by UV irradiation. We could confirm that the first reaction step for both oxidative treatment processes is mainly defluorination, followed by degradation at the piperazine ring of CIP.

  1. [Determination of main degradation products of lignin using reversed-phase high performance liquid chromatography].

    PubMed

    Jiang, Zhijing; Zhu, Junjun; Li, Xin; Lian, Zhina; Yu, Shiyuan; Yong, Qiang

    2011-01-01

    An analytical method using reversed-phase high performance liquid chromatography (RP-HPLC) was developed for the separation and quantitative determination of main degradation products of lignin (4-hydroxybenzoic acid, vanillic acid, syringic acid, 4-hydroxybenzaldehyde, vanillin and syringaldehyde) during the steam exploded pretreatment for corn stovers. The separation was carried out on a C18 column with the mobile phase of acetonitrile-water (containing 1.5% acetic acid) at 30 degrees C at a flow rate of 0.8 mL/min and the detection wavelengths of 254 and 280 nm. Under the optimized conditions, the correlation coefficients of the 6 compounds were between 0.999 9 and 1.000 0. The recoveries of the 6 compounds were all above 96% and the relative standard deviations (n = 6) were less than 2.5%. This method is suitable for the determination of the main degradation products of lignin during the steam exploded pretreatment of lignocellulosics.

  2. PRODUCTION OF TRIFLUOROACETIC ACID COMPOUNDS

    DOEpatents

    Haworth, W.N.; Stacey, M.

    1949-08-30

    A process is described for the preparation of trifluoroacetic acid. Acetone vapor diluted wlth nitrogen and fluorine also diluted with nltrogen are fed separately at a temperature of about 210 deg C into a reaction vessel containing a catalyst mass selected from-the group consisting of silver and gold. The temperature in the reaction vessel is maintained in the range of 200 deg to 250 deg C. The reaction product, trifluoroacetyl fluoride, is absorbed in aqueous alkali solution. Trifluoroacetic acid is recovered from the solution by acidification wlth an acid such as sulfuric followed by steam distillation.

  3. Derivatization of organophosphorus nerve agent degradation products for gas chromatography with ICPMS and TOF-MS detection.

    PubMed

    Richardson, Douglas D; Caruso, Joseph A

    2007-06-01

    Separation and detection of seven V-type (venomous) and G-type (German) organophosphorus nerve agent degradation products by gas chromatography with inductively coupled plasma mass spectrometry (GC-ICPMS) is described. The nonvolatile alkyl phosphonic acid degradation products of interest included ethyl methylphosphonic acid (EMPA, VX acid), isopropyl methylphosphonic acid (IMPA, GB acid), ethyl hydrogen dimethylamidophosphate sodium salt (EDPA, GA acid), isobutyl hydrogen methylphosphonate (IBMPA, RVX acid), as well as pinacolyl methylphosphonic acid (PMPA), methylphosphonic acid (MPA), and cyclohexyl methylphosphonic acid (CMPA, GF acid). N-(tert-Butyldimethylsilyl)-N-methyltrifluroacetamide with 1% TBDMSCl was utilized to form the volatile TBDMS derivatives of the nerve agent degradation products for separation by GC. Exact mass confirmation of the formation of six of the TBDMS derivatives was obtained by GC-time of flight mass spectrometry (TOF-MS). The method developed here allowed for the separation and detection of all seven TBDMS derivatives as well as phosphate in less than ten minutes. Detection limits for the developed method were less than 5 pg with retention times and peak area precisions of less than 0.01 and 6%, respectively. This method was successfully applied to river water and soil matrices. To date this is the first work describing the analysis of chemical warfare agent (CWA) degradation products by GC-ICPMS. PMID:17356819

  4. Microbial degradation of isosaccharinic acid at high pH

    PubMed Central

    Bassil, Naji M; Bryan, Nicholas; Lloyd, Jonathan R

    2015-01-01

    Intermediate-level radioactive waste (ILW), which dominates the radioactive waste inventory in the United Kingdom on a volumetric basis, is proposed to be disposed of via a multibarrier deep geological disposal facility (GDF). ILW is a heterogeneous wasteform that contains substantial amounts of cellulosic material encased in concrete. Upon resaturation of the facility with groundwater, alkali conditions will dominate and will lead to the chemical degradation of cellulose, producing a substantial amount of organic co-contaminants, particularly isosaccharinic acid (ISA). ISA can form soluble complexes with radionuclides, thereby mobilising them and posing a potential threat to the surrounding environment or ‘far field'. Alkaliphilic microorganisms sampled from a legacy lime working site, which is an analogue for an ILW-GDF, were able to degrade ISA and couple this degradation to the reduction of electron acceptors that will dominate as the GDF progresses from an aerobic ‘open phase' through nitrate- and Fe(III)-reducing conditions post closure. Furthermore, pyrosequencing analyses showed that bacterial diversity declined as the reduction potential of the electron acceptor decreased and that more specialised organisms dominated under anaerobic conditions. These results imply that the microbial attenuation of ISA and comparable organic complexants, initially present or formed in situ, may play a role in reducing the mobility of radionuclides from an ILW-GDF, facilitating the reduction of undue pessimism in the long-term performance assessment of such facilities. PMID:25062127

  5. Microbial degradation of isosaccharinic acid at high pH.

    PubMed

    Bassil, Naji M; Bryan, Nicholas; Lloyd, Jonathan R

    2015-02-01

    Intermediate-level radioactive waste (ILW), which dominates the radioactive waste inventory in the United Kingdom on a volumetric basis, is proposed to be disposed of via a multibarrier deep geological disposal facility (GDF). ILW is a heterogeneous wasteform that contains substantial amounts of cellulosic material encased in concrete. Upon resaturation of the facility with groundwater, alkali conditions will dominate and will lead to the chemical degradation of cellulose, producing a substantial amount of organic co-contaminants, particularly isosaccharinic acid (ISA). ISA can form soluble complexes with radionuclides, thereby mobilising them and posing a potential threat to the surrounding environment or 'far field'. Alkaliphilic microorganisms sampled from a legacy lime working site, which is an analogue for an ILW-GDF, were able to degrade ISA and couple this degradation to the reduction of electron acceptors that will dominate as the GDF progresses from an aerobic 'open phase' through nitrate- and Fe(III)-reducing conditions post closure. Furthermore, pyrosequencing analyses showed that bacterial diversity declined as the reduction potential of the electron acceptor decreased and that more specialised organisms dominated under anaerobic conditions. These results imply that the microbial attenuation of ISA and comparable organic complexants, initially present or formed in situ, may play a role in reducing the mobility of radionuclides from an ILW-GDF, facilitating the reduction of undue pessimism in the long-term performance assessment of such facilities. PMID:25062127

  6. Degradation characteristics of 2,4-dichlorophenoxyacetic acid in electro-biological system.

    PubMed

    Zhang, Jingli; Cao, Zhanping; Zhang, Hongwei; Zhao, Lianmei; Sun, Xudong; Mei, Feng

    2013-11-15

    The reductive degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) was studied in an electro-biological system, a biological system and an electric catalytic system, respectively. Electrochemical characteristics were monitored by cyclic voltammetry and the intermediate products of 2,4-D degradation were determined by high speed liquid chromatography (HPLC). The results showed that all 2,4-D degradations in the three systems conformed to the kinetics characteristics of one-order reaction, and the degradation kinetics constants were 28.74 × 10(-2) h(-1), 19.73 × 10(-2) h(-1) and 3.54 × 10(-2) h(-1), respectively. The kinetics constant in the electro-biological system was higher than the sum in the other two systems by 19%. The electrochemical assistance provided the electrons and accelerated the electron transfer rate in the microbial degradation of 2,4-D. The degradation resulted from the microbial reduction strengthened by the electrochemical assistance. The electron transfer existed between the electrode, cytochrome, NAD and the pollutants. A long-range electron transfer process could be achieved on the multi-phase interfaces between the electrode, bacteria and the pollutants.

  7. Reaction kinetics of photocatalytic degradation of sulfosalicylic acid using TiO2 microspheres.

    PubMed

    Wang, Chuan; Zhang, Xianghua; Liu, Hong; Li, Xiangzhong; Li, Wenzhao; Xu, Hengyong

    2009-04-30

    The photocatalytic (PC) degradation kinetics of sulfosalicylic acid (SSA) at different pH using TiO2 microspheres were elucidated by modeling. The resultant model had special consideration of adsorption and pH. The adsorption isotherms showed that the LC/MS(2)-identified intermediates were weakly adsorbed on the TiO2 microspheres, thus their adsorption was neglected in the modeling. By contrast, the SSA was significantly adsorbed, thus its adsorption retained as an item in the model. Consequently, a non-first-order model was obtained. Through the modeling, it was elucidated that the reaction rate increased non-linearly with the SSA adsorption equilibrium constant. Meanwhile, it was elucidated that a pH increase favored the hydroxyl radical production to accelerate the SSA degradation, while impeded the SSA adsorption to slower it, hence a neutral pH caused the fastest SSA degradation. PMID:18762374

  8. Analysis of multiple sweeteners and their degradation products in lassi by HPLC and HPTLC plates.

    PubMed

    George, V; Arora, S; Wadhwa, B K; Singh, A K

    2010-08-01

    A solid phase extraction method using C18 cartridges was standardized for the isolation of multiple sweeteners (aspartame, acesulfame-K and saccharin) and their degradation products (diketopiperazine, Lphenylalanine, acetoacetamide and 2-sulfobenzoic acid) from lassi. Analytical conditions for HPLC were standardized over C18 column using UV detector for the simultaneous separation and estimation of multiple sweeteners and their degradation products in lassi sample isolates. A simple cartridge free method was developed for the isolation of sucralose from lassi. Method was also standardized for qualitative detection and quantitative estimation of sucralose over amino and silica gel plates of HPTLC.

  9. Qualitative Profiling of Polyglucose Degradation Products in Peritoneal Dialysis Fluids.

    PubMed

    Gensberger, Sabrina; Knabner, Carina; Waibel, Reiner; Huppert, Jochen; Pischetsrieder, Monika

    2015-06-16

    Heat sterilization of peritoneal dialysis (PD) fluids leads to partial degradation of the osmotic agent to form reactive carbonyl structures, which significantly reduce the biocompatibility of PD fluids and impair long-term PD therapy. Hence, it is important to know the exact composition of the degradation products to improve biocompatibility of PD fluids. Our study conducted targeted screening for degradation products in polyglucose (icodextrin)-containing PD fluids (pGDPs) by applying o-phenylenediamine (OPD) to form stable derivatives, which were analyzed by ultrahigh-performance liquid chromatography with hyphenated diode array tandem mass spectrometry (UHPLC-DAD-MS/MS). For the first time, specific degradation products of polyglucose, namely, 4-deoxyglucosone (4-DG) and 3,4-dideoxypentosone (3,4-DDPS), could be identified in PD fluids. Further, a reaction product of 5-hydroxymethylfurfural (5-HMF) and OPD could be characterized to be (5-(1H-benzo[d]imidazol-2-yl)furan-2-yl)methanol. Additionally, 3-deoxyglucosone (3-DG) and 3-deoxygalactosone (3-DGal), both known to be present in glucose-based PD fluids, were also detected in polyglucose-containing fluids. Trapping a hitherto unknown degradation product with OPD yielded 1,4-bis(1H-benzo[d]imidazol-2-yl)-3,4-dihydroxybutan-1-one, which was present in heat- as well as filter-sterilized PD fluids.

  10. Qualitative Profiling of Polyglucose Degradation Products in Peritoneal Dialysis Fluids.

    PubMed

    Gensberger, Sabrina; Knabner, Carina; Waibel, Reiner; Huppert, Jochen; Pischetsrieder, Monika

    2015-06-16

    Heat sterilization of peritoneal dialysis (PD) fluids leads to partial degradation of the osmotic agent to form reactive carbonyl structures, which significantly reduce the biocompatibility of PD fluids and impair long-term PD therapy. Hence, it is important to know the exact composition of the degradation products to improve biocompatibility of PD fluids. Our study conducted targeted screening for degradation products in polyglucose (icodextrin)-containing PD fluids (pGDPs) by applying o-phenylenediamine (OPD) to form stable derivatives, which were analyzed by ultrahigh-performance liquid chromatography with hyphenated diode array tandem mass spectrometry (UHPLC-DAD-MS/MS). For the first time, specific degradation products of polyglucose, namely, 4-deoxyglucosone (4-DG) and 3,4-dideoxypentosone (3,4-DDPS), could be identified in PD fluids. Further, a reaction product of 5-hydroxymethylfurfural (5-HMF) and OPD could be characterized to be (5-(1H-benzo[d]imidazol-2-yl)furan-2-yl)methanol. Additionally, 3-deoxyglucosone (3-DG) and 3-deoxygalactosone (3-DGal), both known to be present in glucose-based PD fluids, were also detected in polyglucose-containing fluids. Trapping a hitherto unknown degradation product with OPD yielded 1,4-bis(1H-benzo[d]imidazol-2-yl)-3,4-dihydroxybutan-1-one, which was present in heat- as well as filter-sterilized PD fluids. PMID:25970747

  11. [Analysis of characteristics and products of chlorobenzene degradation with dielectric barrier discharge].

    PubMed

    Jiang, Li-Ying; Cao, Shu-Ling; Zhu, Run-Ye; Chen, Jian-Meng; Su, Fei

    2015-03-01

    For non-biodegradable volatile organic compounds (VOCs) with low water solubility, the tradition biological method can not achieve a satisfactory removal efficiency, so development of high efficiency pre-treatment technology is a hot issue of research. In this experiment, using poor biodegradable chlorobenzene as the target pollutant and dielectric barrier discharge (DBD) non-thermal plasma as the pretreatment technology for biotrickling filter (BTF) , the effect of DBD on the degradation of chlorobenzene was studied by adjusting the technical parameters of DBD. The effects of the inlet concentration, residence time, humidity and peak voltage on decomposition efficiency were investigated and the decomposition products of chlorobenzene were analyzed. Experimental results showed that DBD could effectively remove waste gaseous chlorobenzene, the removal rate of chlorobenzene increased with the increasing peak voltage. When the peak voltage was ≥ 12kV, less effect of residence time on the degradation of chlorobenzene was found. The optimal humidity range of degradation chlorobenzene was 65% - 75%. Through the analysis of degradation products, the species and concentrations of degradation products increased with the increase of discharge voltage. The products were mainly consisted of organic acids and chlorinated hydrocarbons. The water solubility of degradation products was preferable. Furthermore, with the increase of discharge voltage, the biodegradability of degradation products became higher and higher and the biological toxicity was reduced. It had a promoting effect on the degradation of chlorobenzene when the voltage reached 20 kV. Meanwhile, the O3 concentration increased with the increasing discharge voltage and also enhanced with the rising humidity under the same voltage.

  12. Degradation and compatibility behaviors of poly(glycolic acid) grafted chitosan.

    PubMed

    Zhang, Luzhong; Dou, Sufeng; Li, Yan; Yuan, Ying; Ji, Yawei; Wang, Yaling; Yang, Yumin

    2013-07-01

    The films of poly(glycolic acid) grafted chitosan were prepared without using a catalyst to improve the degradable property of chitosan. The films were characterized by Fourier transform-infrared spectroscopy and X-ray photoelectron spectroscopy (XPS). The degradation of the poly(glycolic acid) grafted chitosan films were investigated in the lysozyme solution. In vitro degradation tests revealed that the degradation rate of poly(glycolic acid) grafted chitosan films increased dramatically compared with chitosan. The degradation rate of poly(glycolic acid) grafted chitosan films gradually increased with the increasing of the molar ratio of glycolic acid to chitosan. Additionally, the poly(glycolic acid) grafted chitosan films have good biocompatibility, as demonstrated by in vitro cytotoxicity of the extraction fluids. The biocompatible and biodegradable poly(glycolic acid) grafted chitosan would be an effective material with controllable degradation rate to meet the diverse needs in biomedical fields.

  13. Determination of Acid Dissociation Constant of Pravastatin under Degraded Conditions by Capillary Zone Electrophoresis.

    PubMed

    Takayanagi, Toshio; Amiya, Mika; Shimakami, Natsumi; Yabutani, Tomoki

    2015-01-01

    The acid dissociation constant of pravastatin was determined under degraded conditions. Pravastatin was degraded in an acidic solution (pH = 2.0) for 5 h, and the degradation solution was subjected to the measurement of the effective electrophoretic mobility by capillary zone electrophoresis. Although the amount of pravastatin decreased by the acid degradation, its acid dissociation constant was successfully determined with the residual pravastatin through its effective electrophoretic mobility. The determined acid dissociation constant value agreed well with the one obtained with freshly prepared solution and with some reported values.

  14. [Cellulose degradation and ethanol production of different Clostridium strain].

    PubMed

    Fang, Zhi-guo; Ouyang, Zhi-yun

    2010-08-01

    Cellulose degradation and ethanol production of two types of cellulosic materials with different concentration were evaluated in batch system of mono-cultures of cellulolytic ethanol producing strains (Clostridium thermocellum strain LQRI and Clostridium thermocellum strain VPI), and co-cultures of LQRI or VPI in combination with one of the non-cellulolytic ethanol producing strains (Thermoanaerobacter ethanolicus strains X514 or Thermoanaerobacter ethanolicus 39E). Results demonstrated that higher cellulose degradation abilities about 1.2 times were detected in LQRI mono-culture than in VPI mono-culture, while no significant difference of ethanol yields was found between the two mono-cultures. Abilities of cellulose degradation and ethanol production decreased significantly with the increasing of substrate cellulose concentration (1%, 2%, 5%). In the co-culture system, cellulose degradation abilities of LQRI were also significantly higher than VPI, the former is 1.28-1.58 times of the latter. Cellulose degradation rate of LQRI + Thermoanaerobacter and VPI + Thermoanaerobacter decreased gradually with the increasing of substrate cellulose concentration, while the absolute value of cellulose degradation was also affected by the partner Thermoanaerobacter strain. Additionally, the ethanol yields in the co-cultures of LQRI + Thermoanaerobacter were significantly higher than that in the co-cultures of VPI + Thermoanaerobacter with same Thermoanaerobaeter partner, the former is 1.27-1.77 times of the latter. However, ethanol yields in the co-cultures have not significantly declined with the increasing of substrate cellulose concentration.

  15. Acceleration of the herbicide isoproturon degradation in wheat by glycosyltransferases and salicylic acid.

    PubMed

    Lu, Yi Chen; Zhang, Shuang; Yang, Hong

    2015-01-01

    Isoproturon (IPU) is a herbicide widely used to prevent weeds in cereal production. Due to its extensive use in agriculture, residues of IPU are often detected in soils and crops. Overload of IPU to crops is associated with human health risks. Hence, there is an urgent need to develop an approach to mitigate its accumulation in crops. In this study, the IPU residues and its degradation products in wheat were characterized using ultra performance liquid chromatography-time of fight tandem-mass spectrometer/mass spectrometer (UPLC-TOF-MS/MS). Most detected IPU-derivatives were sugar-conjugated. Degradation and glycosylation of IPU-derivatives could be enhanced by applying salicylic acid (SA). While more sugar-conjugated IPU-derivatives were identified in wheat with SA application, lower levels of IPU were detected, indicating that SA is able to accelerate intracellular IPU catabolism. All structures of IPU-derivatives and sugar-conjugated products were characterized. Comparative data were provided with specific activities and gene expression of certain glucosyltransferases. A pathway with IPU degradation and glucosylation was discussed. Our work indicates that SA-accelerated degradation is practically useful for wheat crops growing in IPU-contaminated soils because such crops with SA application can potentially lower or minimize IPU accumulation in levels below the threshold for adverse effects.

  16. Degradation of net primary production in a semiarid rangeland

    NASA Astrophysics Data System (ADS)

    Jackson, Hasan; Prince, Stephen D.

    2016-08-01

    Anthropogenic land degradation affects many biogeophysical processes, including reductions of net primary production (NPP). Degradation occurs at scales from small fields to continental and global. While measurement and monitoring of NPP in small areas is routine in some studies, for scales larger than 1 km2, and certainly global, there is no regular monitoring and certainly no attempt to measure degradation. Quantitative and repeatable techniques to assess the extent of deleterious effects and monitor changes are needed to evaluate its effects on, for example, economic yields of primary products such as crops, lumber, and forage, and as a measure of land surface properties which are currently missing from dynamic global vegetation models, assessments of carbon sequestration, and land surface models of heat, water, and carbon exchanges. This study employed the local NPP scaling (LNS) approach to identify patterns of anthropogenic degradation of NPP in the Burdekin Dry Tropics (BDT) region of Queensland, Australia, from 2000 to 2013. The method starts with land classification based on the environmental factors presumed to control (NPP) to group pixels having similar potential NPP. Then, satellite remotely sensing data were used to compare actual NPP with its potential. The difference in units of mass of carbon and percentage loss were the measure of degradation. The entire BDT (7.45 × 106 km2) was investigated at a spatial resolution of 250 × 250 m. The average annual reduction in NPP due to anthropogenic land degradation in the entire BDT was -2.14 MgC m-2 yr-1, or 17 % of the non-degraded potential, and the total reduction was -214 MgC yr-1. Extreme average annual losses of 524.8 gC m-2 yr-1 were detected. Approximately 20 % of the BDT was classified as "degraded". Varying severities and rates of degradation were found among the river basins, of which the Belyando and Suttor were highest. Interannual, negative trends in reductions of NPP occurred in 7 % of the

  17. Characterization of radiolytically generated degradation products in the strip section of a TRUEX flowsheet

    SciTech Connect

    Dean R. Peterman; Lonnie G. Olson; Gary S. Groenewold; Rocklan G. McDowell; Richard D. Tillotson; Jack D. Law

    2013-08-01

    This report presents a summary of the work performed to meet the FCRD level 2 milestone M3FT-13IN0302053, “Identification of TRUEX Strip Degradation.” The INL radiolysis test loop has been used to identify radiolytically generated degradation products in the strip section of the TRUEX flowsheet. These data were used to evaluate impact of the formation of radiolytic degradation products in the strip section upon the efficacy of the TRUEX flowsheet for the recovery of trivalent actinides and lanthanides from acidic solution. The nominal composition of the TRUEX solvent used in this study is 0.2 M CMPO and 1.4 M TBP dissolved in n-dodecane and the nominal composition of the TRUEX strip solution is 1.5 M lactic acid and 0.050 M diethylenetriaminepentaacetic acid. Gamma irradiation of a mixture of TRUEX process solvent and stripping solution in the test loop does not adversely impact flowsheet performance as measured by stripping americium ratios. The observed increase in americium stripping distribution ratios with increasing absorbed dose indicates the radiolytic production of organic soluble degradation compounds.

  18. Aerobic degradation of sulfanilic acid using activated sludge.

    PubMed

    Chen, Gang; Cheng, Ka Yu; Ginige, Maneesha P; Kaksonen, Anna H

    2012-01-01

    This paper evaluates the aerobic degradation of sulfanilic acid (SA) by an acclimatized activated sludge. The sludge was enriched for over three months with SA (>500 mg/L) as the sole carbon and energy source and dissolved oxygen (DO, >5mg/L) as the primary electron acceptor. Effects of aeration rate (0-1.74 L/min), DO concentration (0-7 mg/L) and initial SA concentration (104-1085 mg/L) on SA biodegradation were quantified. A modified Haldane substrate inhibition model was used to obtain kinetic parameters of SA biodegradation and oxygen uptake rate (OUR). Positive linear correlations were obtained between OUR and SA degradation rate (R(2)≥ 0.91). Over time, the culture consumed more oxygen per SA degraded, signifying a gradual improvement in SA mineralization (mass ratio of O(2): SA at day 30, 60 and 120 were 0.44, 0.51 and 0.78, respectively). The concomitant release of near stoichiometric quantity of sulphate (3.2 mmol SO(4)(2-) released from 3.3 mmol SA) and the high chemical oxygen demand (COD) removal efficacy (97.1%) indicated that the enriched microbial consortia could drive the overall SA oxidation close to a complete mineralization. In contrast to other pure-culture systems, the ammonium released from the SA oxidation was predominately converted into nitrate, revealing the presence of ammonium-oxidizing bacteria (AOB) in the mixed culture. No apparent inhibitory effect of SA on the nitrification was noted. This work also indicates that aerobic SA biodegradation could be monitored by real-time DO measurement.

  19. Subcritical water hydrolysis of rice straw for reducing sugar production with focus on degradation by-products and kinetic analysis.

    PubMed

    Lin, Richen; Cheng, Jun; Ding, Lingkan; Song, Wenlu; Qi, Feng; Zhou, Junhu; Cen, Kefa

    2015-06-01

    The competitive reactions of reducing sugar production and degradation in the subcritical water hydrolysis of rice straw were investigated to optimise reducing sugar yield. The optimised conditions (280°C, 20 MPa, rice straw concentration of 5 wt.% and agitation speed of 200 rpm) resulted in a reducing sugar yield of 0.346 g/g rice straw because of the enhanced reducing sugar production and decreased sugar degradation. The sugar yield increased when the temperature increased from 250°C to 280°C, but it decreased when the temperature further increased to 300°C because of the degradation of monosaccharides (e.g. glucose and xylose) into by-products (e.g. 2-methyltetrahydrofuran and acetic acid). A first-order reaction model was developed to elucidate the competitive reaction kinetics of sugar production and degradation at various temperatures. The highest reducing sugar yield based on the model was achieved at 280°C with the highest production and lowest degradation rates.

  20. Activation of PPARα by Fatty Acid Accumulation Enhances Fatty Acid Degradation and Sulfatide Synthesis.

    PubMed

    Yang, Yang; Feng, Yuyao; Zhang, Xiaowei; Nakajima, Takero; Tanaka, Naoki; Sugiyama, Eiko; Kamijo, Yuji; Aoyama, Toshifumi

    2016-01-01

    Very-long-chain acyl-CoA dehydrogenase (VLCAD) catalyzes the first reaction in the mitochondrial fatty acid β-oxidation pathway. VLCAD deficiency is associated with the accumulation of fat in multiple organs and tissues, which results in specific clinical features including cardiomyopathy, cardiomegaly, muscle weakness, and hepatic dysfunction in infants. We speculated that the abnormal fatty acid metabolism in VLCAD-deficient individuals might cause cell necrosis by fatty acid toxicity. The accumulation of fatty acids may activate peroxisome proliferator-activated receptor (PPAR), a master regulator of fatty acid metabolism and a potent nuclear receptor for free fatty acids. We examined six skin fibroblast lines, derived from VLCAD-deficient patients and identified fatty acid accumulation and PPARα activation in these cell lines. We then found that the expression levels of three enzymes involved in fatty acid degradation, including long-chain acyl-CoA synthetase (LACS), were increased in a PPARα-dependent manner. This increased expression of LACS might enhance the fatty acyl-CoA supply to fatty acid degradation and sulfatide synthesis pathways. In fact, the first and last reactions in the sulfatide synthesis pathway are regulated by PPARα. Therefore, we also measured the expression levels of enzymes involved in sulfatide metabolism and the regulation of cellular sulfatide content. The levels of these enzymes and cellular sulfatide content both increased in a PPARα-dependent manner. These results indicate that PPARα activation plays defensive and compensative roles by reducing cellular toxicity associated with fatty acids and sulfuric acid. PMID:27644403

  1. Degradation of reactive, acid and basic textile dyes in the presence of ultrasound and rare earths [Lanthanum and Praseodymium].

    PubMed

    Srivastava, Pankaj; Goyal, Shikha; Patnala, Prem Kishore

    2014-11-01

    Degradation of five textile dyes, namely Reactive Red 141 (RR 141), Reactive Blue 21 (RB 21), Acid Red 114 (AR 114), Acid Blue 113 (AB 113) and Basic Violet 16 (BV 16) in aqueous solution has been carried out with ultrasound (US) and in combination with rare earth ions (La(3+) and Pr(3+)). Kinetic analysis of the data showed a pseudo-first order degradation reaction for all the dyes. The rate constant (k), half life (t1/2) and the process efficiency (φ) for various processes in degradation of dyes under different experimental conditions have been calculated. The influence of concentrations of dyes (16-40mg/L), pH (5, 7 and 9) and rare earth ion concentration (4, 12 and 20mg/L) on the degradation of dyes have also been studied. The degradation percentage increased with increasing rare earth amount and decreased with increasing concentration of dyes. Both horn and bath type sonicators were used at 20kHz and 250W for degradation. The sonochemical degradation rate of dyes in the presence of rare earths was related to the type of chromophoric groups in the dye molecule. Degradation sequence of dyes was further examined through LCMS and Raman spectroscopic techniques, which confirmed the sonochemical degradation of dyes to non-toxic end products.

  2. Degradation of reactive, acid and basic textile dyes in the presence of ultrasound and rare earths [Lanthanum and Praseodymium].

    PubMed

    Srivastava, Pankaj; Goyal, Shikha; Patnala, Prem Kishore

    2014-11-01

    Degradation of five textile dyes, namely Reactive Red 141 (RR 141), Reactive Blue 21 (RB 21), Acid Red 114 (AR 114), Acid Blue 113 (AB 113) and Basic Violet 16 (BV 16) in aqueous solution has been carried out with ultrasound (US) and in combination with rare earth ions (La(3+) and Pr(3+)). Kinetic analysis of the data showed a pseudo-first order degradation reaction for all the dyes. The rate constant (k), half life (t1/2) and the process efficiency (φ) for various processes in degradation of dyes under different experimental conditions have been calculated. The influence of concentrations of dyes (16-40mg/L), pH (5, 7 and 9) and rare earth ion concentration (4, 12 and 20mg/L) on the degradation of dyes have also been studied. The degradation percentage increased with increasing rare earth amount and decreased with increasing concentration of dyes. Both horn and bath type sonicators were used at 20kHz and 250W for degradation. The sonochemical degradation rate of dyes in the presence of rare earths was related to the type of chromophoric groups in the dye molecule. Degradation sequence of dyes was further examined through LCMS and Raman spectroscopic techniques, which confirmed the sonochemical degradation of dyes to non-toxic end products. PMID:24491599

  3. Effect of ferric iron on siderophore production and pyrene degradation by Pseudomonas fluorescens 29L.

    PubMed

    Husain, Saleha

    2008-10-01

    The effect of ferric iron [Fe(III)] on pyrene degradation and siderophore production was studied in Pseudomonas fluorescens 29L. In the presence of 0.5 microM of Fe(III) and 50 mg of pyrene per liter of medium as a carbon source, 2.2 mg of pyrene was degraded per liter of medium per day and 25.3 microM of 2,3-DHBA (2,3-dihydroxybenzoic acid) equivalent of siderophores was produced per day. However, the pyrene degradation rate was 1.3 times higher and no siderophores were produced with the addition of 1 microM of Fe(III). Similar trends were seen with 50 mg of succinate per liter of medium as a carbon source, although the growth of strain 29L and the succinate degradation rate were higher. In the absence of siderophore production, pyrene and succinate continued to be biodegraded. This indicates that Fe(III) and not siderophore production affects the hydrocarbon degradation rate. Only 18% of strain 29L mutants capable of growth on pyrene produced siderophores, while among the mutants capable of growth on succinate, only 10% produced siderophores. This indicates that siderophores are not required for pyrene biodegradation. Fe(III) enhances pyrene degradation in Pseudomonas fluorescens 29L but it may be utilized by mechanisms other than siderophores. PMID:18626691

  4. Development of a sensor for polypropylene degradation products.

    SciTech Connect

    Sawyer, Patricia Sue; Howell, Stephen Wayne; Hochrein, James Michael; Dirk, Shawn M.; Bernstein, Robert; Washburn, Cody M.; Graf, Darin C.

    2009-04-01

    This paper presents the development of a sensor to detect the oxidative and radiation induced degradation of polypropylene. Recently we have examined the use of crosslinked assemblies of nanoparticles as a chemiresistor-type sensor for the degradation products. We have developed a simple method that uses a siloxane matrix to fabricate a chemiresistor-type sensor that minimizes the swelling transduction mechanism while optimizing the change in dielectric response. These sensors were exposed with the use of a gas chromatography system to three previously identified polypropylene degradation products including 4-methyl-2-pentanone, acetone, and 2-pentanone. The limits of detection 210 ppb for 4-methy-2-pentanone, 575 ppb for 2-pentanone, and the LoD was unable to be determined for acetone due to incomplete separation from the carbon disulfide carrier.

  5. Production of high molecular weight polylactic acid

    SciTech Connect

    Bonsignore, P.V.

    1995-11-28

    A degradable high molecular weight poly(lactic acid) is described. The poly(lactic acid) has a terminal end group of one of carboxyl or hydroxyl groups with low molecular weight poly(lactic acid) units coupled with linking agents of di-isocyanates, bis-epoxides, bis-oxazolines and bis-ortho esters. The resulting high molecular weight poly(lactic acid) can be used for applications taking advantage of the improved physical properties.

  6. Production of high molecular weight polylactic acid

    SciTech Connect

    Bonsignore, Patrick V.

    1995-01-01

    A degradable high molecular weight poly(lactic acid). A poly(lactic acid) has a terminal end group of one of carboxyl or hydroxyl groups with low molecular weight poly(lactic acid) units coupled with linking agents of di-isocyanates, bis-epoxides, bis-oxazolines and bis-ortho esters. The resulting high molecular weight poly(lactic acid) can be used for applications taking advantage of the improved physical properties.

  7. High performance degradation of azo dye Acid Orange 7 and sulfanilic acid in a laboratory scale reactor after seeding with cultured bacterial strains.

    PubMed

    Coughlin, Michael F; Kinkle, Brian K; Bishop, Paul L

    2003-06-01

    Bacterial strains 1CX and SAD4i--previously isolated from the mixed liquor of a municipal sewage treatment plant--are capable of degrading the azo dye Acid Orange 7 (AO7) and sulfanilic acid, respectively. A rotating drum bioreactor (RDBR), operating under continuous flow and nutrient conditions designed to simulate the effluent from a dye manufacturing plant, was seeded with strains 1CX and SAD4i, forming a biofilm capable of degrading AO7 and sulfanilic acid. In addition, an RDBR containing a pre-existing biofilm capable of degrading AO7, but not sulfanilic acid, was seeded with strain SAD4i alone. Strain SAD4i was incorporated into the existing biofilm and degraded the sulfanilic acid resulting from the degradation of AO7 by indigenous members of the biofilm. The ability to seed a bioreactor with bacterial strains capable of degrading azo dyes, and resulting by-products, in a mixed microbial community suggests that this process could have commercial applications.

  8. Characterization of Wall Teichoic Acid Degradation by the Bacteriophage ϕ29 Appendage Protein GP12 Using Synthetic Substrate Analogs.

    PubMed

    Myers, Cullen L; Ireland, Ronald G; Garrett, Teresa A; Brown, Eric D

    2015-07-31

    The genetics and enzymology of the biosynthesis of wall teichoic acid have been the extensively studied, however, comparatively little is known regarding the enzymatic degradation of this biological polymer. The GP12 protein from the Bacillus subtilis bacteriophage ϕ29 has been implicated as a wall teichoic acid hydrolase. We have studied the wall teichoic acid hydrolase activity of pure, recombinant GP12 using chemically defined wall teichoic acid analogs. The GP12 protein had potent wall teichoic acid hydrolytic activity in vitro and demonstrated ∼13-fold kinetic preference for glycosylated poly(glycerol phosphate) teichoic acid compared with non-glycosylated. Product distribution patterns suggested that the degradation of glycosylated polymers proceeded from the hydroxyl terminus of the polymer, whereas hydrolysis occurred at random sites in the non-glycosylated polymer. In addition, we present evidence that the GP12 protein possesses both phosphodiesterase and phosphomonoesterase activities. PMID:26085106

  9. Potential of wine-associated lactic acid bacteria to degrade biogenic amines.

    PubMed

    García-Ruiz, Almudena; González-Rompinelli, Eva M; Bartolomé, Begoña; Moreno-Arribas, M Victoria

    2011-08-01

    Some lactic acid bacteria (LAB) isolated from fermented foods have been proven to degrade biogenic amines through the production of amine oxidase enzymes. Since little is known about this in relation to wine micro-organisms, this work examined the ability of LAB strains (n=85) isolated from wines and other related enological sources, as well as commercial malolactic starter cultures (n=3) and type strains (n=2), to degrade histamine, tyramine and putrescine. The biogenic amine-degrading ability of the strains was evaluated by RP-HPLC in culture media and wine malolactic fermentation laboratory experiments. Although at different extent, 25% of the LAB isolates were able to degrade histamine, 18% tyramine and 18% putrescine, whereas none of the commercial malolactic starter cultures or type strains were able to degrade any of the tested amines. The greatest biogenic amine-degrading ability was exhibited by 9 strains belonging to the Lactobacillus and Pediococcus groups, and most of them were able to simultaneously degrade at least two of the three studied biogenic amines. Further experiments with one of the strains that showed high biogenic amine-degrading ability (L. casei IFI-CA 52) revealed that cell-free extracts maintained this ability in comparison to the cell suspensions at pH 4.6, indicating that amine-degrading enzymes were effectively extracted from the cells and their action was optimal in the degradation of biogenic amines. In addition, it was confirmed that wine components such as ethanol (12%) and polyphenols (75 mg/L), and wine additives such as SO(2) (30 mg/L), reduced the histamine-degrading ability of L. casei IFI-CA 52 at pH 4.6 by 80%, 85% and 11%, respectively, in cell suspensions, whereas the reduction was 91%, 67% and 50%, respectively, in cell-free extracts. In spite of this adverse influence of the wine matrix, our results proved the potential of wine-associated LAB as a promising strategy to reduce biogenic amines in wine.

  10. Anticataractogenesis Mechanisms of Curcumin and a Comparison of Its Degradation Products: An in Vitro Study.

    PubMed

    Liao, Jiahn-Haur; Huang, Yi-Shiang; Lin, Yu-Ching; Huang, Fu-Yung; Wu, Shih-Hsiung; Wu, Tzu-Hua

    2016-03-16

    Curcumin (Cur) exhibits anticataractogenesis activity. This study aimed to compare the activities of Cur with those of its degradation products in a series of in vitro lens protein turbidity assays. The results show that Cur (200 μM) ameliorates selenite-induced crystallin aggregation, and the mean OD value was 0.10 ± 0.02 (p < 0.05), which was significantly different from controls (0.15 ± 0.01) after incubating for 3 days. However, Cur did not significantly inhibit calcium-induced proteolysis after incubating for 3 days. Such results were supported by isothermal titration calorimetry observation that Cur binds with selenite but not with calcium. Presence of Cur and the degradation products examined (ferulic acid, cinnamic acid, vanillin, and vanillic acid) indicates significantly protective activities on lens γ-crystallins after UVC exposure for 3 h. Among the compounds examined, only ferulic acid exhibited a significant inhibitory effect against UVB-induced turbidity with a mean OD of 0.32 ± 0.01 (p < 0.05), which was significantly different from controls (0.49 ± 0.02). The previously reported anticataract effects of Cur may stem not only from Cur but also from its degradation products through various cataractogenesis mechanisms in vitro. PMID:26905955

  11. Management practices influence productivity of degraded or eroded soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Management practices influence the productivity of eroded or degraded soil. This study investigates the influence of beef manure amendment compared with commercial fertil¬izer (urea) applied at two rates (60 and 120 lb N/a) with two tillage practices (conven¬tional tillage, CT, and no-tillage, NT). ...

  12. Management Practices to Improve Productivity of Degraded/Eroded Soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Productivity of degraded/eroded soils can be restored by using organic amendment, such as manure, and improved soil management. A study is being conducted near Hays, KS, to investigate and compare restorative potential of two nitrogen (N) sources. Dried beef manure and urea fertilizer were each appl...

  13. The geochemical evolution of low-molecular-weight organic acids derived from the degradation of petroleum contaminants in groundwater

    USGS Publications Warehouse

    Cozzarelli, I.M.; Baedecker, M.J.; Eganhouse, R.P.; Goerlitz, D.F.

    1994-01-01

    The geochemical evolution of low-molecular-weight organic acids in groundwater downgradient from a crude-oil spill near Bemidji, Minnesota, was studied over a five year period (1986-1990). The organic acids are metabolic intermediates of the degradation of components of the crude oil and are structurally related to hydrocarbon precursors. The concentrations of organic acids, particularly aliphatic acids, increase as the microbial alteration of hydrocarbons progresses. The organic-acid pool changes in composition and concentration over time and in space as the degradation processes shift from Fe(III) reduction to methanogenesis. Over time, the aquifer system evolves into one in which the groundwater contains more oxidized products of hydrocarbon degradation and the reduced forms of iron, manganese, and nitrogen. Laboratory microcosm experiments with aquifer material support the hypothesis that organic acids observed in the groundwater originate from the microbial degradation of aromatic hydrocarbons under anoxic conditions. The geochemistry of two other shallow aquifers in coastal plain sediments, one contaminated with creosote waste and the other with gasoline, were compared to the Bemidji site. The geochemical evolution of the low-molecular-weight organic acid pool in these systems is controlled, in part, by the presence of electron acceptors available for microbially mediated electron-transfer reactions. The depletion of electron acceptors in aquifers leads to the accumulation of aliphatic organic acids in anoxic groundwater. ?? 1994.

  14. Identification of Unsaturated and 2H Polyfluorocarboxylate Homologous Series and Their Detection in Environmental Samples and as Polymer Degradation Products

    EPA Science Inventory

    A pair of homologous series of polyfluorinated degradation products have been identified, both having structures similar to perfluorocarboxylic acids but (i) having a H substitution for F on the α carbon for 2H polyfluorocarboxylic acids (2HPFCAs) and (ii) bearing a double ...

  15. Degradation of sunscreen agent p-aminobenzoic acid using a combination system of UV irradiation, persulphate and iron(II).

    PubMed

    Xue, Yicen; Dong, Wenbo; Wang, Xiaoning; Bi, Wenlong; Zhai, Pingping; Li, Hongjing; Nie, Minghua

    2016-03-01

    Increased usage and discharge of sunscreens have led to ecological safety crisis, and people are developing the advanced oxidation processes (AOPs) to treat them. The present study aimed to determine the degradation efficiency and mechanism of the sunscreen agent p-aminobenzoic acid (PABA) using the UV/Fe(2+)/persulphate (PS) method. A series of irradiation experiments were conducted to optimise the system conditions and to study the impacts of the natural anion. Free radicals and degradation products were identified in order to clarify the degradation mechanism. Initial PS and Fe(2+) concentrations showed significant impacts on PABA degradation. Natural anions, such as Cl(-), NO3 (-), H2PO4 (-) and HCO3 (-), impeded PABA degradation because of ion (Fe(2+)) capture, radical scavenging or pH effects. Hydroxyl (HO·) and sulphate (SO4 (·-)) radicals were two main radicals observed in the UV/Fe(2+)/PS system; of these, SO4 (·-) showed greater effects on PABA degradation. Over 99 % of the available PABA was completely degraded into carbon dioxide (CO2) and water (H2O) by the UV/Fe(2+)/PS system, and the remaining PABA participated in complex radical reactions. By-products were identified by total ion chromatography and mass spectrometry. Our research provides a treatment process for PABA with high degradation efficiency and environmental safety and introduces a new strategy for sunscreen degradation. PMID:26517998

  16. Degradation of sunscreen agent p-aminobenzoic acid using a combination system of UV irradiation, persulphate and iron(II).

    PubMed

    Xue, Yicen; Dong, Wenbo; Wang, Xiaoning; Bi, Wenlong; Zhai, Pingping; Li, Hongjing; Nie, Minghua

    2016-03-01

    Increased usage and discharge of sunscreens have led to ecological safety crisis, and people are developing the advanced oxidation processes (AOPs) to treat them. The present study aimed to determine the degradation efficiency and mechanism of the sunscreen agent p-aminobenzoic acid (PABA) using the UV/Fe(2+)/persulphate (PS) method. A series of irradiation experiments were conducted to optimise the system conditions and to study the impacts of the natural anion. Free radicals and degradation products were identified in order to clarify the degradation mechanism. Initial PS and Fe(2+) concentrations showed significant impacts on PABA degradation. Natural anions, such as Cl(-), NO3 (-), H2PO4 (-) and HCO3 (-), impeded PABA degradation because of ion (Fe(2+)) capture, radical scavenging or pH effects. Hydroxyl (HO·) and sulphate (SO4 (·-)) radicals were two main radicals observed in the UV/Fe(2+)/PS system; of these, SO4 (·-) showed greater effects on PABA degradation. Over 99 % of the available PABA was completely degraded into carbon dioxide (CO2) and water (H2O) by the UV/Fe(2+)/PS system, and the remaining PABA participated in complex radical reactions. By-products were identified by total ion chromatography and mass spectrometry. Our research provides a treatment process for PABA with high degradation efficiency and environmental safety and introduces a new strategy for sunscreen degradation.

  17. Sonochemical degradation of ethylbenzene in aqueous solution: a product study.

    PubMed

    De Visscher, A; Van Langenhove, H; Van Eenoo, P

    1997-04-01

    The degradation of ethylbenzene in aqueous solution by 520 kHz ultrasound was investigated. The products formed were analysed using solid phase microextraction (SPME), a sampling technique that allows convenient GC-MS and GC-FID analysis in the micromolar range. A broad range of monosubstituted monocyclic and dicyclic aromatic hydrocarbons was found as well as some oxygenated products. The results clearly indicate that pyrolysis is an important pathway of ethylbenzene degradation. The side chain is dehydrogenated, forming styrene, or cleaved. The radicals formed upon cleavage are subsequently added to the double bond of the styrene side chain or recombined. This mechanism explains the formation of most of the products. Formation and breakdown of the reaction products follow first-order kinetics in spite of the fact that the selectivity of the reactions depends on the initial ethylbenzene concentration considerably. Changes in the temperature and the pressure of cavitation are expected to cause this dependence. PMID:11237033

  18. Gradual surface degradation of restorative materials by acidic agents.

    PubMed

    Hengtrakool, Chanothai; Kukiattrakoon, Boonlert; Kedjarune-Leggat, Ureporn

    2011-01-01

    The aim of this study was to investigate the effect of acidic agents on surface roughness and characteristics of four restorative materials. Fifty-two discs were created from each restorative material: metal-reinforced glass ionomer cement (Ketac-S), resin-modified glass ionomer cement (Fuji II LC), resin composite (Filtek Z250), and amalgam (Valiant-PhD); each disc was 12 mm in diameter and 2.5 mm thick. The specimens were divided into four subgroups (n=13) and immersed for 168 hours in four storage media: deionized water (control); citrate buffer solution; green mango juice; and pineapple juice. Surface roughness measurements were performed with a profilometer, both before and after storage media immersion. Surface characteristics were examined using scanning electron microscopy (SEM). Statistical significance among each group was analyzed using two-way repeated ANOVA and Tukey's tests. Ketac-S demonstrated the highest roughness changes after immersion in acidic agents (p<0.05), followed by Fuji II LC. Valiant-PhD and Filtek Z250 illustrated some minor changes over 168 hours. The mango juice produced the greatest degradation effect of all materials tested (p<0.05). SEM photographs demonstrated gradual surface changes of all materials tested after immersions. Of the materials evaluated, amalgam and resin composite may be the most suitable for restorations for patients with tooth surface loss.

  19. Gradual surface degradation of restorative materials by acidic agents.

    PubMed

    Hengtrakool, Chanothai; Kukiattrakoon, Boonlert; Kedjarune-Leggat, Ureporn

    2011-01-01

    The aim of this study was to investigate the effect of acidic agents on surface roughness and characteristics of four restorative materials. Fifty-two discs were created from each restorative material: metal-reinforced glass ionomer cement (Ketac-S), resin-modified glass ionomer cement (Fuji II LC), resin composite (Filtek Z250), and amalgam (Valiant-PhD); each disc was 12 mm in diameter and 2.5 mm thick. The specimens were divided into four subgroups (n=13) and immersed for 168 hours in four storage media: deionized water (control); citrate buffer solution; green mango juice; and pineapple juice. Surface roughness measurements were performed with a profilometer, both before and after storage media immersion. Surface characteristics were examined using scanning electron microscopy (SEM). Statistical significance among each group was analyzed using two-way repeated ANOVA and Tukey's tests. Ketac-S demonstrated the highest roughness changes after immersion in acidic agents (p<0.05), followed by Fuji II LC. Valiant-PhD and Filtek Z250 illustrated some minor changes over 168 hours. The mango juice produced the greatest degradation effect of all materials tested (p<0.05). SEM photographs demonstrated gradual surface changes of all materials tested after immersions. Of the materials evaluated, amalgam and resin composite may be the most suitable for restorations for patients with tooth surface loss. PMID:21903509

  20. Degradation of berenil (diminazene aceturate) in acidic aqueous solution.

    PubMed

    Campbell, Michael; Prankerd, Richard J; Davie, Ashley S; Charman, William N

    2004-10-01

    The trypanocide berenil was assessed for chemical stability over the pH range 1-8 at 37 degrees C and 0.2 M ionic strength. It was found to be sufficiently unstable under acid conditions that its therapeutic efficacy is most likely severely compromised when administered orally. At pH 3, the half-life was 35 min, decreasing to 1.5 min at pH 1.75. Reaction rate constants were corrected for the effects of buffer catalysis and were found to range from 2.00 min(-1) at pH 1 to 6.1 x 10(-6) min(-1) at pH 8. The pH-rate profile displayed a region (pH 1-4) where specific acid catalysis was dominant, followed by a transitional region (pH 5-7), and finally a region (pH >7) where uncatalysed degradation was most important. It is recommended that berenil be enteric coated for formulations to be used in treating Third World parasitic diseases. PMID:15482649

  1. Isolation and characterization of process-related impurities and degradation products in larotaxel.

    PubMed

    Che, Xin; Shen, Li; Xu, Hui; Liu, Ke

    2011-07-15

    The isolation and characterization of the process related impurities and degradation products of larotaxel drug substance were described. Forced degradation of larotaxel was carried out under acidic, basic, oxidation, light and thermal conditions to assess the nature of the impurities. The pure impurities were obtained by semi-preparative LC isolation and analyzed by NMR and MS. The structures of impurities were confirmed as 7,8-cyclopropyl baccatin III, 10-deacetyl larotaxel, 10-deacetyl-7, 8-cyclopropyl baccatin III, 7-acetyl-8-methyl larotaxel and 2',13-bissidechain larotaxel.

  2. Acid preservation systems for food products

    SciTech Connect

    Tiberio, J. E.; Cirigiano, M. C.

    1984-10-16

    Fumaric acid is used in combination with critical amounts of acetic acid to preserve acid containing food products from microbiological spoilage in the absence of or at reduced levels of chemical preservative.

  3. Spectrophotometric and liquid chromatographic determination of trimebutine maleate in the presence of its degradation products.

    PubMed

    El-Gindy, Alaa; Emara, Samy; Hadad, Ghada M

    2003-09-19

    Three methods are presented for the determination of trimebutine maleate (TM) in the presence of its degradation products. The first method was based on a high performance liquid chromatographic (HPLC) separation of TM from its degradation products using an ODS column at ambient temperature with a mobile phase consisting of acetonitrile-5 mM heptane sulfonic acid disodium salt (45:55, v/v, pH 4) with UV detection at 215 nm. The second method depends on using first derivative spectrophotometry (1D) by measurement of the amplitude at 252.2 nm. The third method depends on using first derivative of the ratio spectrophotometry (1DD) by measurement of the amplitude at 282.4 nm where a normalized spectrum of 3,4,5-trimethoxy benzoic acid is used as divisor. The proposed HPLC and 1D methods were used to investigate the kinetics of acidic and alkaline degradation processes. The pH-rate profile of degradation of TM in Britton-Robinson buffer solutions within the pH range 2-11.9 was studied. PMID:12972088

  4. A validated stability-indicating RP-HPLC method for levofloxacin in the presence of degradation products, its process related impurities and identification of oxidative degradant.

    PubMed

    Lalitha Devi, M; Chandrasekhar, K B

    2009-12-01

    The objective of current study was to develop a validated specific stability indicating reversed-phase liquid chromatographic method for the quantitative determination of levofloxacin as well as its related substances determination in bulk samples, pharmaceutical dosage forms in the presence of degradation products and its process related impurities. Forced degradation studies were performed on bulk sample of levofloxacin as per ICH prescribed stress conditions using acid, base, oxidative, water hydrolysis, thermal stress and photolytic degradation to show the stability indicating power of the method. Significant degradation was observed during oxidative stress and the degradation product formed was identified by LCMS/MS, slight degradation in acidic stress and no degradation was observed in other stress conditions. The chromatographic method was optimized using the samples generated from forced degradation studies and the impurity spiked solution. Good resolution between the peaks corresponds to process related impurities and degradation products from the analyte were achieved on ACE C18 column using the mobile phase consists a mixture of 0.5% (v/v) triethyl amine in sodium dihydrogen orthophosphate dihydrate (25 mM; pH 6.0) and methanol using a simple linear gradient. The detection was carried out at 294 nm. The limit of detection and the limit of quantitation for the levofloxacin and its process related impurities were established. The stressed test solutions were assayed against the qualified working standard of levofloxacin and the mass balance in each case was in between 99.4 and 99.8% indicating that the developed LC method was stability indicating. Validation of the developed LC method was carried out as per ICH requirements. The developed LC method was found to be suitable to check the quality of bulk samples of levofloxacin at the time of batch release and also during its stability studies (long term and accelerated stability).

  5. Acid attack on hydrated cement — Effect of mineral acids on the degradation process

    SciTech Connect

    Gutberlet, T.; Hilbig, H.; Beddoe, R.E.

    2015-08-15

    During acid attack on concrete structural components, a degraded layer develops whose properties as a protective barrier are decisive for durability. {sup 29}Si NMR spectroscopy and {sup 27}Al NMR spectroscopy were used with XRD to investigate the degraded layer on hardened cement paste exposed to HCl and H{sub 2}SO{sub 4}. The layer comprises an amorphous silica gel with framework silicates, geminate and single silanol groups in which Si is substituted by Al. Amorphous Al(OH){sub 3} and Fe(OH){sub 3} are present. The gel forms by polycondensation and cross-linking of C-A-S-H chains at AlO{sub 4} bridging tetrahedra. In the transition zone between the degraded layer and the undamaged material, portlandite dissolves and Ca is removed from the C-A-S-H phases maintaining their polymer structure at first. With HCl, monosulphate in the transition zone is converted into Friedel's salt and ettringite. With H{sub 2}SO{sub 4}, gypsum precipitates near the degradation front reducing the thickness of the transition zone and the rate of degradation.

  6. Degradation and enantiomeric fractionation of mecoprop in soil previously exposed to phenoxy acid herbicides - New insights for bioremediation.

    PubMed

    Frková, Zuzana; Johansen, Anders; de Jonge, Lis Wollesen; Olsen, Preben; Gosewinkel, Ulrich; Bester, Kai

    2016-11-01

    Phenoxy acid-contaminated subsoils are common as a result of irregular disposal of residues and production wastes in the past. For enhancing in situ biodegradation at reducing conditions, biostimulation may be an effective option. Some phenoxy acids were marketed in racemic mixtures, and biodegradation rates may differ between enantiomers. Therefore, enantio-preferred degradation of mecoprop (MCPP) in soil was measured to get in-depth information on whether amendment with glucose (BOD equivalents as substrate for microbial growth) and nitrate (redox equivalents for oxidation) can stimulate bioremediation. The degradation processes were studied in soil sampled at different depths (3, 4.5 and 6m) at a Danish urban site with a history of phenoxy acid contamination. We observed preferential degradation of the R-enantiomer only under aerobic conditions in the soil samples from 3- and 6-m depth at environmentally relevant (nM) MCPP concentrations: enantiomer fraction (EF)<0.5. On the other hand, we observed preferential degradation of the S-enantiomer in all samples and treatments at elevated (μM) MCPP concentrations: EF>0.5. Three different microbial communities were discriminated by enantioselective degradation of MCPP: 1) aerobic microorganisms with little enantioselectivity, 2) aerobic microorganisms with R-selectivity and 3) anaerobic denitrifying organisms with S-selectivity. Glucose-amendment did not enhance MCPP degradation, while nitrate amendment enhanced the degradation of high concentrations of the herbicide. PMID:27432728

  7. Degradation and enantiomeric fractionation of mecoprop in soil previously exposed to phenoxy acid herbicides - New insights for bioremediation.

    PubMed

    Frková, Zuzana; Johansen, Anders; de Jonge, Lis Wollesen; Olsen, Preben; Gosewinkel, Ulrich; Bester, Kai

    2016-11-01

    Phenoxy acid-contaminated subsoils are common as a result of irregular disposal of residues and production wastes in the past. For enhancing in situ biodegradation at reducing conditions, biostimulation may be an effective option. Some phenoxy acids were marketed in racemic mixtures, and biodegradation rates may differ between enantiomers. Therefore, enantio-preferred degradation of mecoprop (MCPP) in soil was measured to get in-depth information on whether amendment with glucose (BOD equivalents as substrate for microbial growth) and nitrate (redox equivalents for oxidation) can stimulate bioremediation. The degradation processes were studied in soil sampled at different depths (3, 4.5 and 6m) at a Danish urban site with a history of phenoxy acid contamination. We observed preferential degradation of the R-enantiomer only under aerobic conditions in the soil samples from 3- and 6-m depth at environmentally relevant (nM) MCPP concentrations: enantiomer fraction (EF)<0.5. On the other hand, we observed preferential degradation of the S-enantiomer in all samples and treatments at elevated (μM) MCPP concentrations: EF>0.5. Three different microbial communities were discriminated by enantioselective degradation of MCPP: 1) aerobic microorganisms with little enantioselectivity, 2) aerobic microorganisms with R-selectivity and 3) anaerobic denitrifying organisms with S-selectivity. Glucose-amendment did not enhance MCPP degradation, while nitrate amendment enhanced the degradation of high concentrations of the herbicide.

  8. Synthesis and characterization of acetalated dextran polymer and microparticles with ethanol as a degradation product.

    PubMed

    Kauffman, Kevin J; Do, Clement; Sharma, Sadhana; Gallovic, Matthew D; Bachelder, Eric M; Ainslie, Kristy M

    2012-08-01

    In the field of drug delivery, pH-sensitive polymeric microparticles can be used to release therapeutic payloads slowly in extracellular conditions (pH 7.4) and faster in more acidic areas in vivo, such as sites of inflammation, tumors, or intracellular conditions. Our group currently uses and is further developing the pH-sensitive polymer acetalated dextran (Ac-DEX), which is a biodegradable polymer with highly tunable degradation kinetics. Ac-DEX has displayed enhanced delivery of vaccine and drug components to immune and other cells, making it an extremely desirable polymer for immune applications. Currently, one of the degradation products of Ac-DEX is methanol, which may cause toxicity issues if applied at high concentrations with repeated doses. Therefore, in this manuscript we report the first synthesis and characterization of an Ac-DEX analog which, instead of a methanol degradation product, has a much safer ethanol degradation product. We abbreviate this ethoxy acetal derivatized acetalated dextran polymer as Ace-DEX, with the 'e' to indicate an ethanol degradation product. Like Ac-DEX, Ace-DEX microparticles have tunable degradation rates at pH 5 (intracellular). These rates range from hours to several days and are controlled simply by reaction time. Ace-DEX microparticles also show minimal cytotoxicity compared to commonly used poly(lactic-co-glycolic acid) (PLGA) microparticles when incubated with macrophages. This study aims to enhance the biocompatibility of acetalated dextran-type polymers to allow their use in high volume clinical applications such as multiple dosing and tissue engineering.

  9. Biodegradation of Leonardite by an alkali-producing bacterial community and characterization of the degraded products.

    PubMed

    Gao, Tong-Guo; Jiang, Feng; Yang, Jin-Shui; Li, Bao-Zhen; Yuan, Hong-Li

    2012-03-01

    In this study, three bacterial communities were obtained from 12 Leonardite samples with the aim of identifying a clean, effective, and economic technique for the dissolution of Leonardite, a type of low-grade coal, in the production of humic acid (HA). The biodegradation ability and characteristics of the degraded products of the most effective bacterial community (MCSL-2), which degraded 50% of the Leonardite within 21 days, were further investigated. Analyses of elemental composition, (13)C NMR, and Fourier transform infrared revealed that the contents of C, O, and aliphatic carbon were similar in biodegraded humic acid (bHA) and chemically (alkali) extracted humic acid (cHA). However, the N and carboxyl carbon contents of bHA was higher than that of cHA. Furthermore, a positive correlation was identified between the degradation efficiency and the increasing pH of the culture medium, while increases of manganese peroxidase and esterase activities were also observed. These data demonstrated that both alkali production and enzyme reactions were involved in Leonardite solubilization by MCSL-2, although the former mechanism predominated. No fungus was observed by microscopy. Only four bacterial phylotypes were recognized, and Bacillus licheniformis-related bacteria were identified as the main group in MCSL-2 by analysis of amplified 16S rRNA genes, thus demonstrating that Leonardite degradation ability has a limited distribution in bacteria. Hormone-like bioactivities of bHA were also detected. In this study, a bacterial community capable of Leonardite degradation was identified and the products characterized. These data implicate the use of such bacteria for the exploitation of Leonardite as a biofertilizer.

  10. Impact of Polymer Electrolyte Membrane Degradation Products on Oxygen Reduction Reaction Activity for Platinum Electrocatalysts

    SciTech Connect

    Christ, J. M.; Neyerlin, K. C.; Wang, H.; Richards, R.; Dinh, H. N.

    2014-10-30

    The impact of model membrane degradation compounds on the relevant electrochemical parameters for the oxygen reduction reaction (i.e. electrochemical surface area and catalytic activity), was studied for both polycrystalline Pt and carbon supported Pt electrocatalysts. Model compounds, representing previously published, experimentally determined polymer electrolyte membrane degradation products, were in the form of perfluorinated organic acids that contained combinations of carboxylic and/or sulfonic acid functionality. Perfluorinated carboxylic acids of carbon chain length C1 – C6 were found to have an impact on electrochemical surface area (ECA). The longest chain length acid also hindered the observed oxygen reduction reaction (ORR) performance, resulting in a 17% loss in kinetic current (determined at 0.9 V). Model compounds containing sulfonic acid functional groups alone did not show an effect on Pt ECA or ORR activity. Lastly, greater than a 44% loss in ORR activity at 0.9V was observed for diacid model compounds DA-Naf (perfluoro(2-methyl-3-oxa-5-sulfonic pentanoic) acid) and DA-3M (perfluoro(4-sulfonic butanoic) acid), which contained both sulfonic and carboxylic acid functionalities.

  11. Impact of Polymer Electrolyte Membrane Degradation Products on Oxygen Reduction Reaction Activity for Platinum Electrocatalysts

    DOE PAGES

    Christ, J. M.; Neyerlin, K. C.; Wang, H.; Richards, R.; Dinh, H. N.

    2014-10-30

    The impact of model membrane degradation compounds on the relevant electrochemical parameters for the oxygen reduction reaction (i.e. electrochemical surface area and catalytic activity), was studied for both polycrystalline Pt and carbon supported Pt electrocatalysts. Model compounds, representing previously published, experimentally determined polymer electrolyte membrane degradation products, were in the form of perfluorinated organic acids that contained combinations of carboxylic and/or sulfonic acid functionality. Perfluorinated carboxylic acids of carbon chain length C1 – C6 were found to have an impact on electrochemical surface area (ECA). The longest chain length acid also hindered the observed oxygen reduction reaction (ORR) performance, resultingmore » in a 17% loss in kinetic current (determined at 0.9 V). Model compounds containing sulfonic acid functional groups alone did not show an effect on Pt ECA or ORR activity. Lastly, greater than a 44% loss in ORR activity at 0.9V was observed for diacid model compounds DA-Naf (perfluoro(2-methyl-3-oxa-5-sulfonic pentanoic) acid) and DA-3M (perfluoro(4-sulfonic butanoic) acid), which contained both sulfonic and carboxylic acid functionalities.« less

  12. The Fe(III) and Ga(III) coordination chemistry of 3-(1-hydroxymethylidene) and 3-(1-hydroxydecylidene)-5-(2-hydroxyethyl)pyrrolidine-2,4-dione: Novel tetramic acid degradation products of homoserine lactone bacterial quorum sensing molecules

    PubMed Central

    Romano, Ariel A.; Hahn, Tobias; Davis, Nicole; Lowery, Colin A.; Struss, Anjali K.; Janda, Kim D.; Böttger, Lars H.; Matzanke, Berthold F.; Carrano, Carl J.

    2011-01-01

    Bacteria use small diffusible molecules to exchange information in a process called quorum sensing (QS). An important class of quorum sensing molecules used by Gram-negative bacteria is the family of N-acylhomoserine lactones (HSL). It was recently discovered that a degradation product of the QS molecule 3-oxo-C12-homoserine lactone, the tetramic acid 3-(1-hydroxydecylidene)-5-(2-hydroxyethyl)pyrrolidine-2,4-dione, is a potent antibacterial agent, thus implying roles for QS outside of simply communication. Because these tetramic acids also appear to bind iron with appreciable affinity it was suggested that metal binding might contribute to their biological activity. Here, using a variety of spectroscopic tools, we describe the coordination chemistry of both the methylidene and decylidene tetramic acid derivatives with Fe(III) and Ga(III) and discuss the potential biological significance of such metal binding. PMID:22178671

  13. The Fe(III) and Ga(III) coordination chemistry of 3-(1-hydroxymethylidene) and 3-(1-hydroxydecylidene)-5-(2-hydroxyethyl)pyrrolidine-2,4-dione: novel tetramic acid degradation products of homoserine lactone bacterial quorum sensing molecules.

    PubMed

    Romano, Ariel A; Hahn, Tobias; Davis, Nicole; Lowery, Colin A; Struss, Anjali K; Janda, Kim D; Böttger, Lars H; Matzanke, Berthold F; Carrano, Carl J

    2012-02-01

    Bacteria use small diffusible molecules to exchange information in a process called quorum sensing (QS). An important class of quorum sensing molecules used by Gram-negative bacteria is the family of N-acylhomoserine lactones (HSL). It was recently discovered that a degradation product of the QS molecule 3-oxo-C(12)-homoserine lactone, the tetramic acid 3-(1-hydroxydecylidene)-5-(2-hydroxyethyl)pyrrolidine-2,4-dione, is a potent antibacterial agent, thus implying roles for QS outside of simply communication. Because these tetramic acids also appear to bind iron with appreciable affinity it was suggested that metal binding might contribute to their biological activity. Here, using a variety of spectroscopic tools, we describe the coordination chemistry of both the methylidene and decylidene tetramic acid derivatives with Fe(III) and Ga(III) and discuss the potential biological significance of such metal binding.

  14. The Fe(III) and Ga(III) coordination chemistry of 3-(1-hydroxymethylidene) and 3-(1-hydroxydecylidene)-5-(2-hydroxyethyl)pyrrolidine-2,4-dione: novel tetramic acid degradation products of homoserine lactone bacterial quorum sensing molecules.

    PubMed

    Romano, Ariel A; Hahn, Tobias; Davis, Nicole; Lowery, Colin A; Struss, Anjali K; Janda, Kim D; Böttger, Lars H; Matzanke, Berthold F; Carrano, Carl J

    2012-02-01

    Bacteria use small diffusible molecules to exchange information in a process called quorum sensing (QS). An important class of quorum sensing molecules used by Gram-negative bacteria is the family of N-acylhomoserine lactones (HSL). It was recently discovered that a degradation product of the QS molecule 3-oxo-C(12)-homoserine lactone, the tetramic acid 3-(1-hydroxydecylidene)-5-(2-hydroxyethyl)pyrrolidine-2,4-dione, is a potent antibacterial agent, thus implying roles for QS outside of simply communication. Because these tetramic acids also appear to bind iron with appreciable affinity it was suggested that metal binding might contribute to their biological activity. Here, using a variety of spectroscopic tools, we describe the coordination chemistry of both the methylidene and decylidene tetramic acid derivatives with Fe(III) and Ga(III) and discuss the potential biological significance of such metal binding. PMID:22178671

  15. Product analysis for polyethylene degradation by radiation and thermal ageing

    NASA Astrophysics Data System (ADS)

    Sugimoto, Masaki; Shimada, Akihiko; Kudoh, Hisaaki; Tamura, Kiyotoshi; Seguchi, Tadao

    2013-01-01

    The oxidation products in crosslinked polyethylene for cable insulation formed during thermal and radiation ageing were analyzed by FTIR-ATR. The products were composed of carboxylic acid, carboxylic ester, and carboxylic anhydride for all ageing conditions. The relative yields of carboxylic ester and carboxylic anhydride increased with an increase of temperature for radiation and thermal ageing. The carboxylic acid was the primary oxidation product and the ester and anhydride were secondary products formed by the thermally induced reactions of the carboxylic acids. The carboxylic acid could be produced by chain scission at any temperature followed by the oxidation of the free radicals formed in the polyethylene. The results of the analysis led to formulation of a new oxidation mechanism which was different from the chain reactions via peroxy radicals and peroxides.

  16. Production and degradation of polyhydroxyalkanoates in waste environment

    SciTech Connect

    Lee, S.Y.; Choi, J.

    1999-06-01

    Polyhydroxyalkanoates (PHAs) are energy/carbon storage materials accumulated under unfavorable growth condition in the presence of excess carbon source. PHAs are attracting much attention as substitute for non-degradable petrochemically derived plastics because of their similar material properties to conventional plastics and complete biodegradability under natural environment upon disposal. In this paper, PHA production and degradation in waste environment as well as its role in biological phosphorus removal are reviewed. In biological phosphorus removal process, bacteria accumulating polyphosphate (poly P) uptake carbon substrates and accumulate these as PHA by utilizing energy from breaking down poly P under anaerobic conditions. In the following aerobic condition, accumulated PHA is utilized for energy generation and for the regeneration of poly P. PHA production from waste has been investigated in order to utilize abundant organic compounds in waste water. Since PHA content and PHA productivity that can be obtained are rather low, PHA production from waste product should be considered as a coupled process for reducing the amount of organic waste. PHAs can be rapidly degraded to completion in municipal anaerobic sludge by various microorganisms.

  17. Heterogeneous UV/Fenton degradation of TBBPA catalyzed by titanomagnetite: catalyst characterization, performance and degradation products.

    PubMed

    Zhong, Yuanhong; Liang, Xiaoliang; Zhong, Yin; Zhu, Jianxi; Zhu, Sanyuan; Yuan, Peng; He, Hongping; Zhang, Jing

    2012-10-01

    Tetrabromobisphenol A (TBBPA), a widely used brominated flame retardant, could negatively affect various aspects of mammalian and human physiology, which triggers effective techniques for its removal. In this work, the degradation characteristics of TBBPA in heterogeneous UV/Fenton reaction catalyzed by titanomagnetite (Fe(3-x)Ti(x)O₄) were studied. Batch tests were conducted to evaluate the effects of titanomagnetite dosage, H₂O₂ concentration and titanium content in magnetite on TBBPA degradation. In the system with 0.125 g L⁻¹ of Fe₂.₀₂Ti₀.₉₈O₄ and 10 mmol L⁻¹) of H₂O₂, almost complete degradation of TBBPA (20 mg L⁻¹) was accomplished within 240 min UV irradiation at pH 6.5. The titanium incorporation obviously enhanced the catalytic activity of magnetite. As shown by the XRD and XANES results, titanomagnetite had a spinel structure with Ti⁴⁺ occupying the octahedral sites. On the basis of the degradation products identified by GC-MS, the degradation pathways of TBBPA were proposed. TBBPA possibly underwent the sequential debromination to form TriBBPA, DiBBPA, MonoBBPA and BPA, and β-scission to generate seven brominated compounds. All of these products were finally completely removed from reaction solution. In addition, the reused catalyst Fe₂.₀₂Ti₀.₉₈O₄ still retained the catalytic activity after three cycles, indicating that titanomagnetite had good stability and reusability. These results demonstrated that heterogeneous UV/Fenton reaction catalyzed by titanomagnetite is a promising advanced oxidation technology for the treatment of wastewater containing TBBPA. PMID:22784808

  18. Heterogeneous UV/Fenton degradation of TBBPA catalyzed by titanomagnetite: catalyst characterization, performance and degradation products.

    PubMed

    Zhong, Yuanhong; Liang, Xiaoliang; Zhong, Yin; Zhu, Jianxi; Zhu, Sanyuan; Yuan, Peng; He, Hongping; Zhang, Jing

    2012-10-01

    Tetrabromobisphenol A (TBBPA), a widely used brominated flame retardant, could negatively affect various aspects of mammalian and human physiology, which triggers effective techniques for its removal. In this work, the degradation characteristics of TBBPA in heterogeneous UV/Fenton reaction catalyzed by titanomagnetite (Fe(3-x)Ti(x)O₄) were studied. Batch tests were conducted to evaluate the effects of titanomagnetite dosage, H₂O₂ concentration and titanium content in magnetite on TBBPA degradation. In the system with 0.125 g L⁻¹ of Fe₂.₀₂Ti₀.₉₈O₄ and 10 mmol L⁻¹) of H₂O₂, almost complete degradation of TBBPA (20 mg L⁻¹) was accomplished within 240 min UV irradiation at pH 6.5. The titanium incorporation obviously enhanced the catalytic activity of magnetite. As shown by the XRD and XANES results, titanomagnetite had a spinel structure with Ti⁴⁺ occupying the octahedral sites. On the basis of the degradation products identified by GC-MS, the degradation pathways of TBBPA were proposed. TBBPA possibly underwent the sequential debromination to form TriBBPA, DiBBPA, MonoBBPA and BPA, and β-scission to generate seven brominated compounds. All of these products were finally completely removed from reaction solution. In addition, the reused catalyst Fe₂.₀₂Ti₀.₉₈O₄ still retained the catalytic activity after three cycles, indicating that titanomagnetite had good stability and reusability. These results demonstrated that heterogeneous UV/Fenton reaction catalyzed by titanomagnetite is a promising advanced oxidation technology for the treatment of wastewater containing TBBPA.

  19. Strecker degradation of amino acids promoted by a camphor-derived sulfonamide.

    PubMed

    Carvalho, M Fernanda N N; Ferreira, M João; Knittel, Ana S O; Oliveira, Maria da Conceição; Costa Pessoa, João; Herrmann, Rudolf; Wagner, Gabriele

    2016-01-01

    A camphor-derived sulfonimine with a conjugated carbonyl group, oxoimine 1 (O2SNC10H13O), reacts with amino acids (glycine, L-alanine, L-phenylalanine, L-leucine) to form a compound O2SNC10H13NC10H14NSO2 (2) which was characterized by spectroscopic means (MS and NMR) and supported by DFT calculations. The product, a single diastereoisomer, contains two oxoimine units connected by a -N= bridge, and thus has a structural analogy to the colored product Ruhemann´s purple obtained by the ninhydrin reaction with amino acids. A plausible reaction mechanism that involves zwitterions, a Strecker degradation of an intermediate imine and water-catalyzed tautomerizations was developed by means of DFT calculations on potential transition states. PMID:27340465

  20. Strecker degradation of amino acids promoted by a camphor-derived sulfonamide

    PubMed Central

    Ferreira, M João; Knittel, Ana S O; Oliveira, Maria da Conceição; Costa Pessoa, João; Herrmann, Rudolf; Wagner, Gabriele

    2016-01-01

    Summary A camphor-derived sulfonimine with a conjugated carbonyl group, oxoimine 1 (O2SNC10H13O), reacts with amino acids (glycine, L-alanine, L-phenylalanine, L-leucine) to form a compound O2SNC10H13NC10H14NSO2 (2) which was characterized by spectroscopic means (MS and NMR) and supported by DFT calculations. The product, a single diastereoisomer, contains two oxoimine units connected by a –N= bridge, and thus has a structural analogy to the colored product Ruhemann´s purple obtained by the ninhydrin reaction with amino acids. A plausible reaction mechanism that involves zwitterions, a Strecker degradation of an intermediate imine and water-catalyzed tautomerizations was developed by means of DFT calculations on potential transition states. PMID:27340465

  1. Influence of volatile fatty acid concentration stability on anaerobic degradation of linear alkylbenzene sulfonate.

    PubMed

    Okada, Dagoberto Y; Delforno, Tiago P; Esteves, Andressa S; Polizel, Juliana; Hirasawa, Julia S; Duarte, Iolanda C S; Varesche, Maria B A

    2013-10-15

    Linear alkylbenzene sulfonate (LAS) is an anionic surfactant used in cleaning products, which is usually found in wastewaters. Despite the greater LAS removal rate related to a lower concentrations of volatile fatty acids (VFA), the influence of different ranges of VFA on LAS degradation is not known. LAS degradation was evaluated in upflow anaerobic sludge blanket (UASB) and expanded granular sludge bed (EGSB) reactors at different ranges of VFA concentrations. The reactors were fed with a synthetic wastewater containing LAS (14 mg/L). A greater LAS removal rate (40-80%) was related to the lower and narrower range of acetic acid concentration (1-22 mg/L) in the EGSB reactor. In the UASB reactor, the acetic acid concentrations presented a wider range (2-45 mg/L), and some low LAS removal rates (around 20-25%) were observed even at low acetic acid concentrations (<10 mg/L). The high recirculation rate in the EGSB reactor improved substrate-biomass contact, which resulted in a narrower range of VFA and greater LAS removal rate. PMID:23735461

  2. Nonsedimentable Microvesicles from Senescing Bean Cotyledons Contain Gel Phase-Forming Phospholipid Degradation Products 1

    PubMed Central

    Yao, Kening; Paliyath, Gopinadhan; Thompson, John E.

    1991-01-01

    A mixture of liquid-crystalline and gel-phase lipid domains is detectable by wide angle x-ray diffraction in smooth microsomal membranes isolated from senescent 7-day-old cotyledons, whereas corresponding membranes from young 2-day-old cotyledons are exclusively liquid-crystalline. The gel-phase domains in the senescent membranes comprise phospholipid degradation products including diacylglycerols, free fatty acids, long-chain aldehydes, and long-chain hydrocarbons. The same complement of phospholipid degradation products is also present in nonsedimentable microvesicles isolated from senescent 7-day-old cotyledons by filtration of a 250,000g, 12-hour supernatant through a 300,000 dalton cut-off filter. The phospholipid degradation products in the microvesicles form gel-phase lipid domains when reconstituted into phospholipid liposomes. Nonsedimentable microvesicles of a similar size, which are again enriched in the same gel-phase-forming phospholipid degradation products, are also generated in vitro from smooth microsomal membranes isolated from 2-day-old cotyledons when Ca2+ is added to activate membrane-associated lipolytic enzymes. The Ca2+-treated membranes do not contain detectable gel-phase domains, suggesting that the phospholipid degradation products are completely removed by microvesiculation. The observations collectively indicate that these nonsedimentable microvesicles serve as a vehicle for moving phospholipid degradation products out of membrane bilayers into the cytosol. As noted previously (Yao K, Paliyath G, Humphrey RW, Hallett FR, Thompson JE [1991] Proc Natl Acad Sci USA 88: 2269-2273), the term “deteriosome” connotes this putative function and would serve to distinguish these microvesicles from other cytoplasmic microvesicles unrelated to deterioration. ImagesFigure 2Figure 3Figure 4Figure 5Figure 6Figure 7 PMID:16668427

  3. Reaction kinetics and oxidation product formation in the degradation of acetaminophen by ferrate (VI).

    PubMed

    Wang, Hongyu; Liu, Yibing; Jiang, Jia-Qian

    2016-07-01

    This paper investigates the degradation of acetaminophen (AAP) in aqueous solutions by ferrate (VI), aiming to propose the kinetics, pathways and the oxidation products' formation in the AAP degradation. A series of jar tests were undertaken over ferrate (VI) dosages (molar ratios of ferrate (VI):AAP, 5:1 to 25:1) and pH values (4-11). The effects of co-existing ions (0.2-5 mM) and humic acid (10-50 mg l(-1)) on the AAP removal were investigated. Ferrate (VI) can remove 99.6% AAP (from 1000 μg l(-1)) in 60 min under study conditions when majority of the AAP reduction occurred in the first 5 min. The treatment performance depended on the ferrate(VI) dosage, pH and the type and strength of co-existing ions and humic acid. Raising ferrate (VI) dosage with optimal pH 7 improved the AAP degradation. In the presence of humic acid, the AAP degradation by ferrate (VI) was promoted in a short period (<30 min) but then inhibited with increasing in humic acid contents. The presence of Al(3+), CO3(2-) and PO4(3-) ions declined but the existence of K(+), Na(+), Mg(2+) and Ca(2+) ions can improve the AAP removal. The catalytic function of Al(3+) on the decomposition of ferrate (VI) in aqueous solution was found. The kinetics of the reaction between ferrate (VI) and AAP was pseudo first-order for ferrete (VI) and pseudo second-order for AAP. The pseudo rate constant of ferrate (VI) with AAP was 1.4 × 10(-5) L(2) mg(-2) min(-1). Three oxidation products (OPs) were identified and the AAP degradation pathways were proposed.

  4. Degradation of dissolved organic monomers and short-chain fatty acids in sandy marine sediment by fermentation and sulfate reduction

    NASA Astrophysics Data System (ADS)

    Valdemarsen, Thomas; Kristensen, Erik

    2010-03-01

    The decay of a wide range of organic monomers (short-chain volatile fatty acids (VFA's), amino acids, glucose and a pyrimidine) was studied in marine sediments using experimental plug flow-through reactors. The reactions were followed in the presence and absence of 10 mM SO 42-. Degradation stoichiometry of individual monomers (inflow concentration of 6 mM organic C) was traced by measuring organic (VFA's, amino acids) and inorganic (CO 2, NH 4+, SO 42-) compounds in the outflow. Fermentation of amino acids was efficient and complete during passage through anoxic sediment reactors. Aliphatic amino acids (alanine, serine and glutamate) were primarily recovered as CO 2 (24-34%), formate (3-22%) and acetate (41-83%), whereas only ˜1/3 of the aromatic amino acid (tyrosine) was recovered as CO 2 (13%) and acetate (20%). Fermentation of glucose and cytosine was also efficient (78-86%) with CO 2 (30-35%), formate (3%) and acetate (28-33%) as the primary products. Fermentation of VFA's (acetate, propionate and butyrate), on the other hand, appeared to be product inhibited. The presence of SO 42- markedly stimulated VFA degradation (29-45% efficiency), and these compounds were recovered as CO 2 (17% for butyrate to 100% for acetate) and acetate (51% and 82% for propionate and butyrate, respectively). When reaction stoichiometry during fermentation is compared with compound depletion during sulfate reduction, the higher proportion CO 2 recovery is consistent with lower acetate and formate accumulation. Our results therefore suggest that fermentation reactions mediate the initial degradation of added organic compounds, even during active sulfate reduction. Fermentative degradation stoichiometry also suggested significant H 2 production, and >50% of sulfate reduction appeared to be fuelled by H 2. Furthermore, our results suggest that fermentation was the primary deamination step during degradation of the amino acids and cytosine.

  5. Effects of organic acids, amino acids and ethanol on the radio-degradation of patulin in an aqueous model system

    NASA Astrophysics Data System (ADS)

    Yun, Hyejeong; Lim, Sangyong; Jo, Cheorun; Chung, Jinwoo; Kim, Soohyun; Kwon, Joong-Ho; Kim, Dongho

    2008-06-01

    The effects of organic acids, amino acids, and ethanol on the radio-degradation of patulin by gamma irradiation in an aqueous model system were investigated. The patulin, dissolved in distilled water at a concentration of 50 ppm, was practically degraded by the gamma irradiation at the dose of 1.0 kGy, while 33% of the patulin remained in apple juice. In the aqueous model system, the radio-degradation of patulin was partially inhibited by the addition of organic acids, amino acids, and ethanol. The proportions of remaining patulin after irradiation with the dose of 1.0 kGy in the 1% solution of malic acid, citric acid, lactic acid, acetic acid, ascorbic acid, and ethanol were 31.4%, 2.3%, 31.2%, 6.1%, 50.8%, and 12.5%, respectively. During 30 days of storage, the remaining patulin was reduced gradually in the solution of ascorbic acid and malic acid compared to being stable in other samples. The amino acids, serine, threonine, and histidine, inhibited the radio-degradation of patulin. In conclusion, it was suggested that 1 kGy of gamma irradiation (recommended radiation doses for radicidation and/or quarantine in fruits) is effective for the reduction of patulin, but the nutritional elements should be considered because the radio-degradation effects are environment dependent.

  6. Counteraction of antibiotic production and degradation stabilizes microbial communities

    PubMed Central

    Kelsic, Eric D.; Zhao, Jeffrey; Vetsigian, Kalin; Kishony, Roy

    2015-01-01

    Summary A major challenge in theoretical ecology is understanding how natural microbial communities support species diversity1-8, and in particular how antibiotic producing, sensitive and resistant species coexist9-15. While cyclic “rock-paper-scissors” interactions can stabilize communities in spatial environments9-11, coexistence in unstructured environments remains an enigma12,16. Here, using simulations and analytical models, we show that the opposing actions of antibiotic production and degradation enable coexistence even in well-mixed environments. Coexistence depends on 3-way interactions where an antibiotic degrading species attenuates the inhibitory interactions between two other species. These 3-way interactions enable coexistence that is robust to substantial differences in inherent species growth rates and to invasion by “cheating” species that cease producing or degrading antibiotics. At least two antibiotics are required for stability, with greater numbers of antibiotics enabling more complex communities and diverse dynamical behaviors ranging from stable fixed-points to limit cycles and chaos. Together, these results show how multi-species antibiotic interactions can generate ecological stability in both spatial and mixed microbial communities, suggesting strategies for engineering synthetic ecosystems and highlighting the importance of toxin production and degradation for microbial biodiversity. PMID:25992546

  7. Characterization of 2,4-dichlorophenoxyacetic acid and 2,4,5-trichlorophenoxyacetic acid-degrading fungi in Vietnamese soils.

    PubMed

    Itoh, Kazuhito; Kinoshita, Masahiro; Morishita, Shigeyuki; Chida, Masateru; Suyama, Kousuke

    2013-04-01

    Sixty-nine fungal strains were isolated countrywide from 10 Vietnamese soils, in areas both with and without a history of exposure to Agent Orange, and their degrading activities on the phenoxy acid herbicides 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), as well as related compounds, were examined. Among taxonomically various fungi, 45, 12 and 4% of the isolates degraded phenoxyacetic acid (PA), 2,4-D and 2,4,5-T, respectively. While the PA-degrading fungi were distributed to all sites and among many genera, the 2,4-D-degraders were found only in order Eurotiales in class Eurotiomycetes. All of the 2,4,5-T-degrading fungal strains were phylogenetically close to Eupenicillium spp. and were isolated from southern Vietnam. As a degradation intermediate, the corresponding phenol compounds were detected in some strains. The degradation substrate spectrum for 26 compounds of Eupenicillium spp. strains including 2,4,5-T-degraders and -non-degraders seemed to be related to phylogenetic similarity and soil sampling location of the isolates. These results suggest that the heavily contaminated environments enhanced the adaptation of the phylogenetic group of Eupenicillium spp. toward to obtain the ability to degrade 2,4,5-T. PMID:23167922

  8. Characterization of 2,4-dichlorophenoxyacetic acid and 2,4,5-trichlorophenoxyacetic acid-degrading fungi in Vietnamese soils.

    PubMed

    Itoh, Kazuhito; Kinoshita, Masahiro; Morishita, Shigeyuki; Chida, Masateru; Suyama, Kousuke

    2013-04-01

    Sixty-nine fungal strains were isolated countrywide from 10 Vietnamese soils, in areas both with and without a history of exposure to Agent Orange, and their degrading activities on the phenoxy acid herbicides 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), as well as related compounds, were examined. Among taxonomically various fungi, 45, 12 and 4% of the isolates degraded phenoxyacetic acid (PA), 2,4-D and 2,4,5-T, respectively. While the PA-degrading fungi were distributed to all sites and among many genera, the 2,4-D-degraders were found only in order Eurotiales in class Eurotiomycetes. All of the 2,4,5-T-degrading fungal strains were phylogenetically close to Eupenicillium spp. and were isolated from southern Vietnam. As a degradation intermediate, the corresponding phenol compounds were detected in some strains. The degradation substrate spectrum for 26 compounds of Eupenicillium spp. strains including 2,4,5-T-degraders and -non-degraders seemed to be related to phylogenetic similarity and soil sampling location of the isolates. These results suggest that the heavily contaminated environments enhanced the adaptation of the phylogenetic group of Eupenicillium spp. toward to obtain the ability to degrade 2,4,5-T.

  9. Degradation of Acid Orange 7 in an Atmospheric-Pressure Plasma-Solution System (Gliding Discharge)

    NASA Astrophysics Data System (ADS)

    NI, Mingjiang; YANG, Huan; CHEN, Tong; ZHANG, Hao; WU, Angjian; DU, Changming; LI, Xiaodong

    2015-03-01

    In this work, a plasma-solution system was applied to the degradation of Acid Orange 7 (AO7). The effects of initial concentration and type of feed gases (air, oxygen, nitrogen or argon) were studied. As the initial concentration increased from 100 mg/L to 160 mg/L, the discolouration rate of AO7 decreased from 99.3% to 95.9%, whereas the COD removal rate decreased from 37.9% to 22.6%. Air provided the best discolouration and COD removal rates (99.3% and 37.9%, respectively). In the presence of a zero-valent iron (ZVI) catalyst, the AO7 COD removal rate increased to 76.4%. The degradation products were analysed by a GC-MS, revealing that the degradation of the dye molecule was initiated through the cleavage of the -N=N- bond before finally being converted to organic acids. supported by National Natural Science Foundation of China (Nos. 50908237, 51076142) and the Open Foundation of the State Key Laboratory of Clean Energy Utilization of China (No. ZJUCEU2009008)

  10. Study on the kinetics and transformation products of salicylic acid in water via ozonation.

    PubMed

    Hu, Ruikang; Zhang, Lifeng; Hu, Jiangyong

    2016-06-01

    As salicylic acid is one of widely used pharmaceuticals, its residue has been found in various environmental water systems e.g. wastewater, surface water, treated water and drinking water. It has been reported that salicylic acid can be efficiently removed by advanced oxidation processes, but there are few studies on its transformation products and ozonation mechanisms during ozonation process. The objective of this study is to characterize the transformation products, investigate the degradation mechanisms at different pH, and propose the ozonation pathways of salicylic acid. The results showed that the rate of degradation was about 10 times higher at acidic condition than that at alkaline condition in the first 1 min when 1 mg L(-1) of ozone solution was added into 1 mg L(-1) of salicylic acid solution. It was proposed that ozone direct oxidation mechanism dominates at acidic condition, while indirect OH radical mechanism dominates at alkaline condition. A two stages pseudo-first order reaction was proposed at different pH conditions. Various hydroxylation products, carbonyl compounds and carboxylic acids, such as 2,5-dihydroxylbenzoic acid, 2,3-dihydroxylbenzoic acid, catechol, formaldehyde, glyoxal, acetaldehyde, maleic acid, acetic acid and oxalic acid etc. were identified as ozonation transformation products. In addition, acrylic acid was identified, for the first time, as ozonation transformation products through high resolution liquid chromatography-time of flight mass spectrometer. The information demonstrated in this study will help us to better understand the possible effects of ozonation products on the water quality. The degradation pathways of salicylic acid by ozonation in water sample were proposed. As both O3 and OH radical were important in the reactions, the degradation pathways of salicylic acid by ozonation in water sample were proposed at acidic and basic conditions. To our knowledge, there was no integrated study reported on the ozonation of

  11. Study on the kinetics and transformation products of salicylic acid in water via ozonation.

    PubMed

    Hu, Ruikang; Zhang, Lifeng; Hu, Jiangyong

    2016-06-01

    As salicylic acid is one of widely used pharmaceuticals, its residue has been found in various environmental water systems e.g. wastewater, surface water, treated water and drinking water. It has been reported that salicylic acid can be efficiently removed by advanced oxidation processes, but there are few studies on its transformation products and ozonation mechanisms during ozonation process. The objective of this study is to characterize the transformation products, investigate the degradation mechanisms at different pH, and propose the ozonation pathways of salicylic acid. The results showed that the rate of degradation was about 10 times higher at acidic condition than that at alkaline condition in the first 1 min when 1 mg L(-1) of ozone solution was added into 1 mg L(-1) of salicylic acid solution. It was proposed that ozone direct oxidation mechanism dominates at acidic condition, while indirect OH radical mechanism dominates at alkaline condition. A two stages pseudo-first order reaction was proposed at different pH conditions. Various hydroxylation products, carbonyl compounds and carboxylic acids, such as 2,5-dihydroxylbenzoic acid, 2,3-dihydroxylbenzoic acid, catechol, formaldehyde, glyoxal, acetaldehyde, maleic acid, acetic acid and oxalic acid etc. were identified as ozonation transformation products. In addition, acrylic acid was identified, for the first time, as ozonation transformation products through high resolution liquid chromatography-time of flight mass spectrometer. The information demonstrated in this study will help us to better understand the possible effects of ozonation products on the water quality. The degradation pathways of salicylic acid by ozonation in water sample were proposed. As both O3 and OH radical were important in the reactions, the degradation pathways of salicylic acid by ozonation in water sample were proposed at acidic and basic conditions. To our knowledge, there was no integrated study reported on the ozonation of

  12. Mechanism and kinetics of electrochemical degradation of uric acid using conductive-diamond anodes.

    PubMed

    Dbira, Sondos; Bensalah, Nasr; Bedoui, Ahmed

    2016-12-01

    Uric acid (UA) is one of the principal effluents of urine wastewaters, widely used in agriculture as fertilizer, which is potentially dangerous and biorefractory. Hence, the degradation of UA (2,6,8-trihydroxy purine) in aqueous solution of pH 3.0 has been studied by conductive-diamond electrochemical oxidation. Hydroxyl radicals formed from water oxidation at the surface of boron-doped diamond anodes were the main oxidizing agents. Effects of current density and supporting electrolyte on the degradation rate and process efficiency are assessed. Results show that the increase of current density from 20 to 60 mA cm(-2) leads to a decrease in the efficiency of the electrochemical process. In addition, the best degradation occurred in the presence of NaCl as conductive electrolyte. Interestingly, an almost total mineralization of 50 ppm UA was obtained when anodic oxidation was performed at low current densities (20 mA cm(-2)) and in the presence of NaCl. This result confirmed that the electrolysis using diamond anodes is a very interesting technology for the treatment of UA. The identification of UA transformation products was performed by high-performance liquid chromatography (HPLC). HPLC analysis of treated solutions revealed that oxalic acid and urea were the two intermediates found. Oxalic acid was the most persistent product. Based on detected intermediates and bibliographic research, a mechanism of UA mineralization by anodic oxidation has been proposed. Ionic chromatography analysis confirmed the release of [Formula: see text] and [Formula: see text] ions during UA mineralization. PMID:27108970

  13. Mechanism and kinetics of electrochemical degradation of uric acid using conductive-diamond anodes.

    PubMed

    Dbira, Sondos; Bensalah, Nasr; Bedoui, Ahmed

    2016-12-01

    Uric acid (UA) is one of the principal effluents of urine wastewaters, widely used in agriculture as fertilizer, which is potentially dangerous and biorefractory. Hence, the degradation of UA (2,6,8-trihydroxy purine) in aqueous solution of pH 3.0 has been studied by conductive-diamond electrochemical oxidation. Hydroxyl radicals formed from water oxidation at the surface of boron-doped diamond anodes were the main oxidizing agents. Effects of current density and supporting electrolyte on the degradation rate and process efficiency are assessed. Results show that the increase of current density from 20 to 60 mA cm(-2) leads to a decrease in the efficiency of the electrochemical process. In addition, the best degradation occurred in the presence of NaCl as conductive electrolyte. Interestingly, an almost total mineralization of 50 ppm UA was obtained when anodic oxidation was performed at low current densities (20 mA cm(-2)) and in the presence of NaCl. This result confirmed that the electrolysis using diamond anodes is a very interesting technology for the treatment of UA. The identification of UA transformation products was performed by high-performance liquid chromatography (HPLC). HPLC analysis of treated solutions revealed that oxalic acid and urea were the two intermediates found. Oxalic acid was the most persistent product. Based on detected intermediates and bibliographic research, a mechanism of UA mineralization by anodic oxidation has been proposed. Ionic chromatography analysis confirmed the release of [Formula: see text] and [Formula: see text] ions during UA mineralization.

  14. Spectroscopic detection and quantification of heme and heme degradation products.

    PubMed

    Neugebauer, U; März, A; Henkel, T; Schmitt, M; Popp, J

    2012-12-01

    Heme and heme degradation products play critical roles in numerous biological phenomena which until now have only been partially understood. One reason for this is the very low concentrations at which free heme, its complexes and the partly unstable degradation products occur in living cells. Therefore, powerful and specific detection methods are needed. In this contribution, the potential of nondestructive Raman spectroscopy for the detection, quantification and discrimination of heme and heme degradation products is investigated. Resonance Raman spectroscopy using different excitation wavelengths (413, 476, 532, and 752 nm) is employed to estimate the limit of detection for hemin, myoglobin, biliverdin, and bilirubin. Concentrations in the low micromolar range (down to 3 μmol/L) could be reliably detected when utilizing the resonance enhancement effect. Furthermore, a systematic study on the surface-enhanced Raman spectroscopy (SERS) detection of hemin in the presence of other cellular components, such as the highly similar cytochrome c, DNA, and the important antioxidant glutathione, is presented. A microfluidic device was used to reproducibly create a segmented flow of aqueous droplets and oil compartments. Those aqueous droplets acted as model chambers where the analytes have to compete for the colloid. With the help of statistical analysis, it was possible to detect and differentiate the pure substances as well as the binary mixtures and gain insights into their interaction.

  15. Superoxide mediated production of hydroxyl radicals by magnetite nanoparticles: demonstration in the degradation of 2-chlorobiphenyl.

    PubMed

    Fang, Guo-Dong; Zhou, Dong-Mei; Dionysiou, Dionysios D

    2013-04-15

    Increasing attention has been paid to magnetite nanoparticles (MNPs) due to their highly reductive reactivity toward environmental contaminants. However, there is little information related to the generation of reactive oxygen species (ROS) by MNPs, which in fact plays a vital role for the transformation of contaminants. In this paper, the degradation of 2-chlorobiphenyl (2-CB) by MNPs was investigated. The role of ROS generated by MNPs in this process was elucidated. The results demonstrated that hydroxyl radicals (OH) generated by MNPs at low pH could efficiently degrade 2-CB. The mechanism of the formation of OH by MNPs was divided into two steps: (i) the superoxide radical anion (O2(-)) mediated production of hydrogen peroxide (H2O2), and (ii) the reaction of formed H2O2 with Fe(II) dissolved from MNPs to produce OH through Fenton reaction. Comparison of the degradation products of 2-CB by MNPs with MNPs/ethanol and Fenton reagents further supported the involvement of OH in the degradation of 2-CB. The degradation efficiency of 2-CB by MNPs under acidic conditions was higher than that in alkaline solution. These findings provide a new insight into the understanding of reactivity of MNPs for the transformation of 2-CB and possibly other relevant environmental contaminants. PMID:23434481

  16. Fate of products of degradation processes: consequences for climatic change.

    PubMed

    Slanina, J; ten Brink, H M; Khlystov, A

    1999-03-01

    The end products of atmospheric degradation are not only CO2 and H2O but also sulfate and nitrate depending on the chemical composition of the substances which are subject to degradation processes. Atmospheric degradation has thus a direct influence on the radiative balance of the earth not only due to formation of greenhouse gases but also of aerosols. Aerosols of a diameter of 0.1 to 2 micrometer, reflect short wave sunlight very efficiently leading to a radiative forcing which is estimated to be about -0.8 watt per m2 by IPCC. Aerosols also influence the radiative balance by way of cloud formation. If more aerosols are present, clouds are formed with more and smaller droplets and these clouds have a higher albedo and are more stable compared to clouds with larger droplets. Not only sulfate, but also nitrate and polar organic compounds, formed as intermediates in degradation processes, contribute to this direct and indirect aerosol effect. Estimates for the Netherlands indicate a direct effect of -4 watt m-2 and an indirect effect of as large as -5 watt m-2. About one third is caused by sulfates, one third by nitrates and last third by polar organic compounds. This large radiative forcing is obviously non-uniform and depends on local conditions.

  17. Use of LC-MS/TOF, LC-MS(n), NMR and LC-NMR in characterization of stress degradation products: Application to cilazapril.

    PubMed

    Narayanam, Mallikarjun; Sahu, Archana; Singh, Saranjit

    2015-01-01

    Forced degradation studies on cilazapril were carried out according to ICH and WHO guidelines. Significant degradation of the drug was observed in acid and base conditions, resulting primarily in cilazaprilat. In neutral condition, five degradation products were formed, while under oxidative condition, two degradation products were generated. In total, seven degradation products were formed, which were separated on an Inertsil C-18 column using a stability-indicating HPLC method. Structure elucidation of the degradation products was done by using sophisticated and hyphenated tools like, LC-MS/TOF, LC-MS(n), on-line H/D exchange, LC-NMR and NMR. Initially, comprehensive mass fragmentation pathway of the drug was laid down. Critical comparison of mass fragmentation pathways of the drug and its hydrolytic degradation products allowed structure characterization of the latter. 1D and 2D proton LC-NMR studies further confirmed the proposed structures of hydrolytic degradation products. The oxidative degradation products could not be characterized using LC-MS and LC-NMR tools. Hence, these degradation products were isolated using preparative HPLC and extensive 1D ((1)H, (13)C, DEPT) and 2D (COSY, TOCSY, HETCOR and HMBC) NMR studies were performed to ascertain their structures. Finally, degradation pathways and mechanisms of degradation of the drug were outlined. PMID:25890215

  18. Isolation, Characterization of a Potential Degradation Product of Aspirin and an HPLC Method for Quantitative Estimation of Its Impurities.

    PubMed

    Acharya, Subasranjan; Daniel, Alex; Gyadangi, Bharath; Ramsamy, Sriramulu

    2015-10-01

    In this work, a new degradation product of Aspirin was isolated, characterized and analyzed along with other impurities. New unknown degradation product referred as UP was observed exceeding the limit of ICH Q3B identification thresholds in the stability study of Aspirin and Dipyridamole capsule. The UP isolated from the thermal degradation sample was further studied by IR, Mass and (1)H NMR spectrometry, revealing structural similarities with the parent molecule. Finally, UP was identified as a new compound generated from the interaction of Aspirin and Salicylic acid to form a dehydrated product. A specific HPLC method was developed and validated for the analysis of UP and other Aspirin impurities (A, B, C, E and other unknown degradation products). The proposed method was successfully employed for estimation of Aspirin impurities in a pharmaceutical preparation of Aspirin (Immediate Release) and Dipyridamole (Extended Release) Capsules.

  19. Fungal degradation of coal as a pretreatment for methane production

    USGS Publications Warehouse

    Haider, Rizwan; Ghauri, Muhammad A.; SanFilipo, John R.; Jones, Elizabeth J.; Orem, William H.; Tatu, Calin A.; Akhtar, Kalsoom; Akhtar, Nasrin

    2013-01-01

    Coal conversion technologies can help in taking advantage of huge low rank coal reserves by converting those into alternative fuels like methane. In this regard, fungal degradation of coal can serve as a pretreatment step in order to make coal a suitable substrate for biological beneficiation. A fungal isolate MW1, identified as Penicillium chrysogenum on the basis of fungal ITS sequences, was isolated from a core sample of coal, taken from a well drilled by the US. Geological Survey in Montana, USA. The low rank coal samples, from major coal fields of Pakistan, were treated with MW1 for 7 days in the presence of 0.1% ammonium sulfate as nitrogen source and 0.1% glucose as a supplemental carbon source. Liquid extracts were analyzed through Excitation–Emission Matrix Spectroscopy (EEMS) to obtain qualitative estimates of solubilized coal; these analyses indicated the release of complex organic functionalities. In addition, GC–MS analysis of these extracts confirmed the presence of single ring aromatics, polyaromatic hydrocarbons (PAHs), aromatic nitrogen compounds and aliphatics. Subsequently, the released organics were subjected to a bioassay for the generation of methane which conferred the potential application of fungal degradation as pretreatment. Additionally, fungal-mediated degradation was also prospected for extracting some other chemical entities like humic acids from brown coals with high huminite content especially from Thar, the largest lignite reserve of Pakistan.

  20. Identification and Characterization of Hydrolytic Degradation Products of Cefditoren Pivoxil using LC and LC-MS/TOF

    PubMed Central

    Gawande, V. T.; Bothara, K. G.; Singh, A.; Mahajan, A. A.

    2015-01-01

    The present research work was carried out to determine stability of cefditoren pivoxil, an orally absorbed prodrug that is rapidly hydrolysed by intestinal esterases to the active cephalosporin cefditoren. Cefditoren was subjected to stress conditions recommended by the International Conference on Harmonization of Technical Requirements for Registration of Pharmaceuticals for Human Use guideline Q1A (R2). Cefditoren pivoxil was susceptible for degradation under acidic, alkaline and neutral hydrolytic conditions while it was stable under photolytic and thermal stress conditions. Separation of cefditoren and degradation products were carried out by using HPLC. The unknown degradation products were characterized by liquid chromatography-mass spectrometry/time of flight studies. Structures were proposed for each fragment based on best possible molecular formula and complete degradation pathways were reported for cefditoren and its degradants. PMID:25767321

  1. Liquid chromatography-fluorescence and liquid chromatography-mass spectrometry detection of tryptophan degradation products of a recombinant monoclonal antibody.

    PubMed

    Nowak, Christine; Ponniah, Gomathinayagam; Cheng, Guilong; Kita, Adriana; Neill, Alyssa; Kori, Yekaterina; Liu, Hongcheng

    2016-03-01

    Light exposure is one of several conditions used to study the degradation pathways of recombinant monoclonal antibodies. Tryptophan is of particular interest among the 20 amino acids because it is the most photosensitive. Tryptophan degradation forms several products, including an even stronger photosensitizer and several reactive oxygen species. The current study reports a specific peptide mapping procedure to monitor tryptophan degradation. Instead of monitoring peptides using UV 214 nm, fluorescence detection with an excitation wavelength of 295 nm and an emission wavelength of 350 nm was used to enable specific detection of tryptophan-containing peptides. Peaks that decreased in area over time are likely to contain susceptible tryptophan residues. This observation can allow further liquid chromatography-mass spectrometry (LC-MS) analysis to focus only on those peaks to confirm tryptophan degradation products. After confirmation of tryptophan degradation, susceptibility of tryptophan residues can be compared based on the peak area decrease. PMID:26717898

  2. The quantitative determination of aspirin and its degradation products in a model solution aerosol.

    PubMed

    Blondino, F E; Byron, P R

    1995-02-01

    Formulation of pressurized aerosol solutions in propellants for inhalation requires the use of high quantities of surfactants to solubilize the drug. Due to the lipophilic nature of these surfactants, analytical difficulties are created for those wishing to quantify the drug and its degradation products. In order to quantify drug and degradation products by LC it is necessary to separate surfactant and analytes prior to chromatography. To illustrate a typical situation, a method was developed for the analysis of acetylsalicyclic acid (approximately 2.5 x 10(-3) M) and its major degradation products (salicylic acid, acetylsalicylsalicylic acid and salicylsalicylic acid) solubilized in trichloromonofluoromethane (CFC-11) containing 10(-2) M sorbitan trioleate (Span 85). Surfactant extraction problems were reviewed experimentally. The presentation of all analytes and the surfactant, dissolved in hexane, to silica solid phase extraction columns, followed by elution in a polar solvent, was found to be an efficient way of separating this lipophilic surfactant from the analytes. The final assay employed propellant evaporation, reconstitution of the non-volatiles in hexane, normal phase solid phase extraction (recoveries of 100 +/- 10% were observed for all analytes), elution and dilution with mobile phase, and reversed-phase liquid chromatography (Econosphere C8 5 microns, 4.6 x 250 mm). The assay utilized a mobile phase of water, methanol, tetrahydrofuran and 1 M phosphoric acid with ultraviolet detection at 275 nm. Using external standards, linear calibration curves of peak height versus concentration were obtained for all analytes in the expected concentration ranges (r > 0.991). As it is described, the assay had a relative standard deviation of < or = 3.7% for all analytes.

  3. Electrochemical degradation of trichloroacetic acid in aqueous media: influence of the electrode material.

    PubMed

    Esclapez, M D; Díez-García, M I; Sàez, V; Bonete, P; González-García, José

    2013-01-01

    The electrochemical degradation of trichloroacetic acid (TCAA) in water has been analysed through voltammetric studies with a rotating disc electrode and controlled-potential bulk electrolyses. The influence of the mass-transport conditions and initial concentration of TCAA for titanium, stainless steel and carbon electrodes has been studied. It is shown that the electrochemical reduction of TCAA takes place prior to the massive hydrogen evolution in the potential window for all electrode materials studied. The current efficiency is high (> 18%) compared with those normally reported in the literature, and the fractional conversion is above 50% for all the electrodes studied. Only dichloroacetic acid (DCAA) and chloride anions were routinely detected as reduction products for any of the electrodes, and reasonable values of mass balance error were obtained. Of the three materials studied, the titanium cathode gave the best results. PMID:23530352

  4. [Photocatalytic degradation kinetics of perfluorooctanoic acid (PFOA) in TiO2 dispersion and its mechanism].

    PubMed

    Li, Ming-Jie; Yu, Ze-Bin; Chen, Ying; Wang, Li; Liu, Qing; Liu, Yu-Xin; He, Li-Li

    2014-07-01

    Decomposition of perfluorooctanoic acid (PFOA) is of prime importance since it is recognized as a persistent organic pollutant and is widespread in the environment. Heterogeneous photocatalytic decomposition of PFOA by TiO2 (P25) was investigated under 254 nm UV light. Experimental conditions including initial pH, TiO2 content and PFOA concentration, were varied to demonstrate their effects on the decomposition of PFOA. It was observed that the photocatalytic degradation kinetics of PFOA could be fitted to the quasi-first-order equation. The pH played a determinant role in the decomposition of PFOA and the presence of O2 increased the degradation rate. Optimal conditions for a complete removal were obtained using 1.5 g x L(-1) TiO2 at pH 3 in air atmosphere, with a rate constant of 0.420 6 h(-1). The contribution experiments of various reactive species produced during the photocatalysis were also investigated with the addition of different scavengers and it was found that photogenerated holes (h+) was the major reactive species which was responsible for 66.1% of the degradation rate, and the *OH was involved in PFOA degradation as well. In addition, the photocatalytic experiment with the addition of NaF indicated that the adsorption of PFOA was of primary importance for the photocatalytic decomposition. Perfluorocarboxylic acids (PFCAs) with shorter carbon chain length as intermediates and products were identified with UPLC-QTOF/MS, and a possible mechanism for PFOA decomposition was proposed.

  5. Halotolerance, ligninase production and herbicide degradation ability of basidiomycetes strains

    PubMed Central

    Arakaki, R.L.; Monteiro, D.A.; Boscolo, M.; Dasilva, R.; Gomes, E.

    2013-01-01

    Fungi have been recently recognized as organisms able to grow in presence of high salt concentration with halophilic and halotolerance properties and their ligninolytic enzyme complex have an unspecific action enabling their use to degradation of a number of xenobiotic compounds. In this work, both the effect of salt and polyols on growth of the basidiomycetes strains, on their ability to produce ligninolytic enzyme and diuron degradation were evaluated. Results showed that the presence of NaCl in the culture medium affected fungal specimens in different ways. Seven out of ten tested strains had growth inhibited by salt while Dacryopinax elegans SXS323, Polyporus sp MCA128 and Datronia stereoides MCA167 fungi exhibited higher biomass production in medium containing 0.5 and 0.6 mol.L−1 of NaCl, suggesting to be halotolerant. Polyols such as glycerol and mannitol added into the culture media improved the biomass and ligninases production by D. elegans but the fungus did not reveal consumption of these polyols from media. This fungus degraded diuron in medium control, in presence of NaCl as well as polyols, produced MnP, LiP and laccase. PMID:24688513

  6. Interactions between amino-acid-degrading bacteria and methanogenic bacteria in anaerobic digestion

    SciTech Connect

    Nagase, M.; Matsuo, T.

    1982-10-01

    The degradation of amino acids in anaerobic digestion was examined in terms of the interactions between amino-acid-degrading bacteria and methanogenic bacteria. Certain amino acids were degraded oxidatively by dehydrogenation, with methanogenic bacteria acting as H/sub 2/ acceptors. The inhibition of methanogenesis by chloroform also inhibited the degradation of these amino acids and/or caused variations in the composition of volatile acids produced from them. The presence of glycine reduced the inhibitory effect caused by chloroform, probably because glycine acted as an H/sub 2/ acceptor in place of methanogenic bacteria. This fact suggested that the coupled oxidation-reduction reactions between two amino acids - one acting as the H/sub 2/ donor and the other acting as the H/sub 2/ acceptor - may occur in the anaerobic digestion of proteins or amino-acid mixtures. The conversion of some proteins to volatile acids was not affected when methanogensis was inhibited by chloroform. This suggested that the component amino acids of proteins may be degraded by the coupled oxidation-reduction reactions and that the degradation of proteins may not be dependent on the activity of methanogenic bacteria as H/sub 2/ acceptors.

  7. The degradation products of aniline in the solutions with ozone and kinetic investigations.

    PubMed

    Turhan, Kadir; Uzman, Suheyla

    2007-10-01

    Aromatic compounds are extensively used in several industries and can cause pollution in water sources. This work aims at examining the degradability of aniline in aqueous solutions by ozone-induced cleavage, and at determining the kinetics of the cited cleavage reactions. Aniline was prepared in four different concentrations and the flow rate of ozone supplied to each solution was selected. Aniline solutions were ozonated at low and high pH, so as to compare both molecular and hydroxyl free radical mechanisms, respectively. The main identified aromatic by-products were nitrobenzene and azobenzene when the experiment was carried out at acidic pH. Formation of nitrobenzene, azobenzene, azoxybenzene and 2-pyridine carboxylic acid (picolinic acid) was observed when the ozonization was carried out at basic pH. All the aromatic by-products found were less toxic than the raw materials. The pseudo-first-order constants in aniline concentrations were calculated.

  8. Forced degradation of fingolimod: effect of co-solvent and characterization of degradation products by UHPLC-Q-TOF-MS/MS and 1H NMR.

    PubMed

    Patel, Prinesh N; Kalariya, Pradipbhai D; Gananadhamu, S; Srinivas, R

    2015-11-10

    Fingolimod (FGL), an immunomodulator drug for treating multiple sclerosis, was subjected to hydrolysis (acidic, alkaline and neutral), oxidation, photolysis and thermal stress, as per International Conference on Harmonization specified conditions. The drug showed extensive degradation under base hydrolysis, however, it was stable under all other conditions. A total of three degradation products (DPs) were observed. The chromatographic separation of the drug and its degradation products was achieved on a Fortis C18 (100×2.1mm, 1.7μm) column with a mobile phase composed of 0.1% formic acid (Solvent A) and acetonitrile (Solvent B) in gradient mode. All the DPs were identified and characterized by liquid chromatography-quadrupole time of flight-mass spectrometry (LC-Q-TOF-MS) in combination with accurate mass measurements. The major DP was isolated and characterized by Nuclear Magnetic resonance spectroscopy. This is a typical case of degradation where acetonitrile used as co-solvent in stress studies, reacts with FGL in base hydrolytic conditions to produce acetylated DPs. Hence, it can be suggested that acetonitrile is not preferable as a co-solvent for stress degradation of FGL. The developed UHPLC method was validated as per ICH guidelines.

  9. Forced degradation of fingolimod: effect of co-solvent and characterization of degradation products by UHPLC-Q-TOF-MS/MS and 1H NMR.

    PubMed

    Patel, Prinesh N; Kalariya, Pradipbhai D; Gananadhamu, S; Srinivas, R

    2015-11-10

    Fingolimod (FGL), an immunomodulator drug for treating multiple sclerosis, was subjected to hydrolysis (acidic, alkaline and neutral), oxidation, photolysis and thermal stress, as per International Conference on Harmonization specified conditions. The drug showed extensive degradation under base hydrolysis, however, it was stable under all other conditions. A total of three degradation products (DPs) were observed. The chromatographic separation of the drug and its degradation products was achieved on a Fortis C18 (100×2.1mm, 1.7μm) column with a mobile phase composed of 0.1% formic acid (Solvent A) and acetonitrile (Solvent B) in gradient mode. All the DPs were identified and characterized by liquid chromatography-quadrupole time of flight-mass spectrometry (LC-Q-TOF-MS) in combination with accurate mass measurements. The major DP was isolated and characterized by Nuclear Magnetic resonance spectroscopy. This is a typical case of degradation where acetonitrile used as co-solvent in stress studies, reacts with FGL in base hydrolytic conditions to produce acetylated DPs. Hence, it can be suggested that acetonitrile is not preferable as a co-solvent for stress degradation of FGL. The developed UHPLC method was validated as per ICH guidelines. PMID:26279369

  10. Laboratory photochemical processing of aqueous aerosols: formation and degradation of dicarboxylic acids, oxocarboxylic acids and α-dicarbonyls

    NASA Astrophysics Data System (ADS)

    Pavuluri, C. M.; Kawamura, K.; Mihalopoulos, N.; Swaminathan, T.

    2015-07-01

    To better understand the photochemical processing of dicarboxylic acids and related polar compounds, we conducted batch UV irradiation experiments on two types of aerosol samples collected from India, which represent anthropogenic (AA) and biogenic (BA) aerosols, for time periods of 0.5 to 120 h. The irradiated samples were analyzed for molecular compositions of diacids, oxoacids and α-dicarbonyls. The results show that photochemical degradation of oxalic (C2), malonic (C3) and other C8-C12 diacids overwhelmed their production in aqueous aerosols, whereas succinic acid (C4) and C5-C7 diacids showed a significant increase (ca. 10 times) during the course of irradiation experiments. The photochemical formation of oxoacids and α-dicarbonyls overwhelmed their degradation during the early stages of experiment except for ω-oxooctanoic acid (ωC8), which showed a similar pattern to that of C4. We also found a gradual decrease in the relative abundance of C2 to total diacids and an increase in the relative abundance of C4 during prolonged experiment. Based on the changes in concentrations and mass ratios of selected species with the irradiation time, we hypothesize that iron-catalyzed photolysis of C2 and C3 diacids controls their concentrations in Fe-rich atmospheric waters, whereas photochemical formation of C4 diacid (via ωC8) is enhanced with photochemical processing of aqueous aerosols in the atmosphere. This study demonstrates that the ambient aerosols contain abundant precursors that produce diacids, oxoacids and α-dicarbonyls, although some species such as oxalic acid decompose extensively during an early stage of photochemical processing.

  11. Laboratory photochemical processing of aqueous aerosols: formation and degradation of dicarboxylic acids, oxocarboxylic acids and α-dicarbonyls

    NASA Astrophysics Data System (ADS)

    Pavuluri, C. M.; Kawamura, K.; Mihalopoulos, N.; Swaminathan, T.

    2015-01-01

    To better understand the photochemical processing of dicarboxylic acids and related polar compounds, we conducted batch UV irradiation experiments on two types of aerosol samples collected from India, which represent anthropogenic (AA) and biogenic aerosols (BA), for time periods of 0.5 to 120 h. The irradiated samples were analyzed for molecular compositions of diacids, oxoacids and α-dicarbonyls. The results show that photochemical degradation of oxalic (C2) and malonic (C3) and other C8-C12 diacids overwhelmed their production in aqueous aerosols whereas succinic acid (C4) and C5-C7 diacids showed a significant increase (ca. 10 times) during the course of irradiation experiments. The photochemical formation of oxoacids and α-dicarbonyls overwhelmed their degradation during the early stages of experiment, except for ω-oxooctanoic acid (ωC8) that showed a similar pattern to that of C4. We also found a gradual decrease in the relative abundance of C2 to total diacids and an increase in the relative abundance of C4 during prolonged experiment. Based on the changes in concentrations and mass ratios of selected species with the irradiation time, we hypothesize that iron-catalyzed photolysis of C2 and C3 diacids dominates their concentrations in Fe-rich atmospheric waters, whereas photochemical formation of C4 diacid (via ωC8) is enhanced with photochemical processing of aqueous aerosols in the atmosphere. This study demonstrates that the ambient aerosols contain abundant precursors that produce diacids, oxoacids and α-dicarbonyls, although some species such as oxalic acid decompose extensively during an early stage of photochemical processing.

  12. ANALYTICAL METHOD DEVELOPMENT FOR ALACHLOR ESA AND OTHER ACETANILIDE HERBICIDE DEGRADATION PRODUCTS

    EPA Science Inventory

    In 1998, USEPA published a Drinking Water Contaminant Candidate List (CCL) of 50 chemicals and 10 microorganisms. "Alachlor ESA and other acetanilide herbicide degradation products" is listed on the the 1998 CCL. Acetanilide degradation products are generally more water soluble...

  13. DETERMINATION OF INTERFERING TRIAZINE DEGRADATION PRODUCTS BY GAS CHROMATOGRAPHY-ION TRAP MASS SPECTROMETRY

    EPA Science Inventory

    Deethyl atrazine (DEA), along with other triazine degradation products, has been added to the US Environmental Protection Agency's Drinking Water Contaminant Candidate List (CCL). In its gas chromatographic (GC) analysis, deethyl atrazine, a degradation product of atrazine, can ...

  14. Production of carboxylic acid and salt co-products

    SciTech Connect

    Hanchar, Robert J.; Kleff, Susanne; Guettler, Michael V.

    2014-09-09

    This invention provide processes for producing carboxylic acid product, along with useful salts. The carboxylic acid product that is produced according to this invention is preferably a C.sub.2-C.sub.12 carboxylic acid. Among the salts produced in the process of the invention are ammonium salts.

  15. Main chain acid-degradable polymers for the delivery of bioactive materials

    DOEpatents

    Frechet, Jean M. J.; Standley, Stephany M.; Jain, Rachna; Lee, Cameron C.

    2012-03-20

    Novel main chain acid degradable polymer backbones and drug delivery systems comprised of materials capable of delivering bioactive materials to cells for use as vaccines or other therapeutic agents are described. The polymers are synthesized using monomers that contain acid-degradable linkages cleavable under mild acidic conditions. The main chain of the resulting polymers readily degrade into many small molecules at low pH, but remain relatively stable and intact at physiological pH. The new materials have the common characteristic of being able to degrade by acid hydrolysis under conditions commonly found within the endosomal or lysosomal compartments of cells thereby releasing their payload within the cell. The materials can also be used for the delivery of therapeutics to the acidic regions of tumors and other sites of inflammation.

  16. [Study on hydrophilicity and degradability of polyvinyl alcohol/polylactic acid blend film].

    PubMed

    Wang, Hualin; Sheng, Mingang; Zhai, Linfeng; Li, Yanhong

    2008-02-01

    Based on casting and solvent evaporation method, the degradable PLA/PVA blend film was prepared with polylactic acid (PLA) and polyvinyl alcohol (PVA) as raw material. The moisture absorbability, water absorbability and degradability of the polylactic acid/polyvinyl alcohol (PLA/PVA) blend film were studied; also the degradation mechanism of blend film was investigated. The results showed that the moisture absorption and water absorption of blend film decreased as the concentration of PLA increased. The degradation process of blend film in the normal saline is conducted by stepwise. At the forepart, the degradation of PLA played an important role, while PVA was the main degradation substance later. The solvent acidity could catalyze the degradation of PLA, and degradation of PLA was always turning from noncrystalline region to crystalline region. PVA had abilities to accelerate the degradation of PLA by increasing the hydrophilicity of the blend film and by breaking the crystallinity of PLA. Therefore, the hydrophilicity and degradability of PLA/PVA blend film can be controlled in a certain range by adjusting the proportion of PLA and PVA. PMID:18435276

  17. Hydrogen production: two stage processes for waste degradation.

    PubMed

    Gómez, X; Fernández, C; Fierro, J; Sánchez, M E; Escapa, A; Morán, A

    2011-09-01

    The dark fermentation process generates hydrogen by biological means. It presents two main advantages: fulfilling requirements for mild operational conditions and gaining benefit from the residual biomass. The process itself may be seen as a pre-treatment step in a complete stabilisation chain, with the aim of attaining the valorisation of residual biomass. However, increasing the yield of H2 production is an imperative task. In this manuscript, a review of recent work in the field of fermentative hydrogen production is presented. As dark fermentation has a maximum yield of 33% (on sugars), a description is also presented of possible second stage processes for the degradation of dark fermentation effluents. Alternatives considered were photofermentation and bioelectrochemical systems (BES) as processes capable of converting fermentation sub-products into H2. Anaerobic digestion as a final stabilisation stage was also considered owing to the wide application of this technology in the treatment of bio-wastes.

  18. Biodegradation of the alkaline cellulose degradation products generated during radioactive waste disposal.

    PubMed

    Rout, Simon P; Radford, Jessica; Laws, Andrew P; Sweeney, Francis; Elmekawy, Ahmed; Gillie, Lisa J; Humphreys, Paul N

    2014-01-01

    The anoxic, alkaline hydrolysis of cellulosic materials generates a range of cellulose degradation products (CDP) including α and β forms of isosaccharinic acid (ISA) and is expected to occur in radioactive waste disposal sites receiving intermediate level radioactive wastes. The generation of ISA's is of particular relevance to the disposal of these wastes since they are able to form complexes with radioelements such as Pu enhancing their migration. This study demonstrates that microbial communities present in near-surface anoxic sediments are able to degrade CDP including both forms of ISA via iron reduction, sulphate reduction and methanogenesis, without any prior exposure to these substrates. No significant difference (n = 6, p = 0.118) in α and β ISA degradation rates were seen under either iron reducing, sulphate reducing or methanogenic conditions, giving an overall mean degradation rate of 4.7 × 10(-2) hr(-1) (SE ± 2.9 × 10(-3)). These results suggest that a radioactive waste disposal site is likely to be colonised by organisms able to degrade CDP and associated ISA's during the construction and operational phase of the facility.

  19. Biodegradation of the alkaline cellulose degradation products generated during radioactive waste disposal.

    PubMed

    Rout, Simon P; Radford, Jessica; Laws, Andrew P; Sweeney, Francis; Elmekawy, Ahmed; Gillie, Lisa J; Humphreys, Paul N

    2014-01-01

    The anoxic, alkaline hydrolysis of cellulosic materials generates a range of cellulose degradation products (CDP) including α and β forms of isosaccharinic acid (ISA) and is expected to occur in radioactive waste disposal sites receiving intermediate level radioactive wastes. The generation of ISA's is of particular relevance to the disposal of these wastes since they are able to form complexes with radioelements such as Pu enhancing their migration. This study demonstrates that microbial communities present in near-surface anoxic sediments are able to degrade CDP including both forms of ISA via iron reduction, sulphate reduction and methanogenesis, without any prior exposure to these substrates. No significant difference (n = 6, p = 0.118) in α and β ISA degradation rates were seen under either iron reducing, sulphate reducing or methanogenic conditions, giving an overall mean degradation rate of 4.7 × 10(-2) hr(-1) (SE ± 2.9 × 10(-3)). These results suggest that a radioactive waste disposal site is likely to be colonised by organisms able to degrade CDP and associated ISA's during the construction and operational phase of the facility. PMID:25268118

  20. Biodegradation of the Alkaline Cellulose Degradation Products Generated during Radioactive Waste Disposal

    PubMed Central

    Rout, Simon P.; Radford, Jessica; Laws, Andrew P.; Sweeney, Francis; Elmekawy, Ahmed; Gillie, Lisa J.; Humphreys, Paul N.

    2014-01-01

    The anoxic, alkaline hydrolysis of cellulosic materials generates a range of cellulose degradation products (CDP) including α and β forms of isosaccharinic acid (ISA) and is expected to occur in radioactive waste disposal sites receiving intermediate level radioactive wastes. The generation of ISA's is of particular relevance to the disposal of these wastes since they are able to form complexes with radioelements such as Pu enhancing their migration. This study demonstrates that microbial communities present in near-surface anoxic sediments are able to degrade CDP including both forms of ISA via iron reduction, sulphate reduction and methanogenesis, without any prior exposure to these substrates. No significant difference (n = 6, p = 0.118) in α and β ISA degradation rates were seen under either iron reducing, sulphate reducing or methanogenic conditions, giving an overall mean degradation rate of 4.7×10−2 hr−1 (SE±2.9×10−3). These results suggest that a radioactive waste disposal site is likely to be colonised by organisms able to degrade CDP and associated ISA's during the construction and operational phase of the facility. PMID:25268118

  1. Characterization of stress degradation products of duloxetine hydrochloride employing LC-UV/PDA and LC-MS/TOF studies.

    PubMed

    Chadha, Renu; Bali, Alka; Bansal, Gulshan

    2016-03-20

    Duloxetine HCl was subjected to forced degradation under conditions of hydrolysis (neutral, acidic and alkaline), oxidation, photolysis and thermal stress, as suggested in the ICH guideline Q1A(R2). The drug showed significant degradation under acidic, alkaline and aqueous hydrolytic as well as photolytic conditions. The drug remained stable under thermal and oxidative stress conditions. In total, seventeen degradation products (I-XVII) were formed under varied conditions, which could be separated by chromatography of respective degraded solutions on C18 (250 mm×4.6 mm; 5 μ, Nulceodur) column using isocratic elution method. Detection wavelength was selected as 290 nm. MS/TOF accurate mass studies were carried out to establish the complete fragmentation pathway of the drug and degradation products, which, in turn, was utilized in characterization of the products. The degradation pathway of the drug leading to generation of fifteen products I-X, XII-XIII, XV-XVII was postulated and this has not been reported so far. PMID:26775018

  2. Degradation of trans-ferulic acid in acidic aqueous medium by anodic oxidation, electro-Fenton and photoelectro-Fenton.

    PubMed

    Flores, Nelly; Sirés, Ignasi; Garrido, José Antonio; Centellas, Francesc; Rodríguez, Rosa María; Cabot, Pere Lluís; Brillas, Enric

    2016-12-01

    Solutions of pH 3.0 containing trans-ferulic acid, a phenolic compound in olive oil mill wastewater, have been comparatively degraded by anodic oxidation with electrogenerated H2O2 (AO-H2O2), electro-Fenton (EF) and photoelectro-Fenton (PEF). Trials were performed with a BDD/air-diffusion cell, where oxidizing OH was produced from water discharge at the BDD anode and/or in the solution bulk from Fenton's reaction between cathodically generated H2O2 and added catalytic Fe(2+). The substrate was very slowly removed by AO-H2O2, whereas it was very rapidly abated by EF and PEF, at similar rate in both cases, due to its fast reaction with OH in the bulk. The AO-H2O2 process yielded a slightly lower mineralization than EF, which promoted the accumulation of barely oxidizable products like Fe(III) complexes. In contrast, the fast photolysis of these latter species under irradiation with UVA light in PEF led to an almost total mineralization with 98% total organic carbon decay. The effect of current density and substrate concentration on the performance of all treatments was examined. Several solar PEF (SPEF) trials showed its viability for the treatment of wastewater containing trans-ferulic acid at larger scale. Four primary aromatic products were identified by GC-MS analysis of electrolyzed solutions, and final carboxylic acids like fumaric, acetic and oxalic were detected by ion-exclusion HPLC. A reaction sequence for trans-ferulic acid mineralization involving all the detected products is finally proposed. PMID:26691522

  3. Degradation of trans-ferulic acid in acidic aqueous medium by anodic oxidation, electro-Fenton and photoelectro-Fenton.

    PubMed

    Flores, Nelly; Sirés, Ignasi; Garrido, José Antonio; Centellas, Francesc; Rodríguez, Rosa María; Cabot, Pere Lluís; Brillas, Enric

    2016-12-01

    Solutions of pH 3.0 containing trans-ferulic acid, a phenolic compound in olive oil mill wastewater, have been comparatively degraded by anodic oxidation with electrogenerated H2O2 (AO-H2O2), electro-Fenton (EF) and photoelectro-Fenton (PEF). Trials were performed with a BDD/air-diffusion cell, where oxidizing OH was produced from water discharge at the BDD anode and/or in the solution bulk from Fenton's reaction between cathodically generated H2O2 and added catalytic Fe(2+). The substrate was very slowly removed by AO-H2O2, whereas it was very rapidly abated by EF and PEF, at similar rate in both cases, due to its fast reaction with OH in the bulk. The AO-H2O2 process yielded a slightly lower mineralization than EF, which promoted the accumulation of barely oxidizable products like Fe(III) complexes. In contrast, the fast photolysis of these latter species under irradiation with UVA light in PEF led to an almost total mineralization with 98% total organic carbon decay. The effect of current density and substrate concentration on the performance of all treatments was examined. Several solar PEF (SPEF) trials showed its viability for the treatment of wastewater containing trans-ferulic acid at larger scale. Four primary aromatic products were identified by GC-MS analysis of electrolyzed solutions, and final carboxylic acids like fumaric, acetic and oxalic were detected by ion-exclusion HPLC. A reaction sequence for trans-ferulic acid mineralization involving all the detected products is finally proposed.

  4. Comparison of N-nitrosodiethylamine degradation in water by UV irradiation and UV/O3: efficiency, product and mechanism.

    PubMed

    Xu, Bingbing; Chen, Zhonglin; Qi, Fei; Ma, Jun; Wu, Fengchang

    2010-07-15

    N-nitrosodiethylamine (NDEA) is a member of nitrosamines, which is strong carcinogenic. In order to explore an effective treatment method for NDEA removal from water, sole UV irradiation and UV/O(3) were carried out in this study. The removal efficiency, degradation products and pathways were compared between those two processes. Results showed that NDEA removal efficiency achieved 99% within 15 min by both UV and UV/O(3). Degradation reaction well followed pseudo-first-order kinetics. Water pH had different effect on NDEA degradation in those two processes. Acidic and neutral conditions were good for NDEA degradation by sole UV irradiation. However, NDEA underwent rapid degradation under various pH conditions in the UV/O(3) process. Though the ozone introduction in the UV/O(3) process had little effect on NDEA degradation efficiency, it had significant effect on its degradation products and pathways. Methylamine, dimethylamine, ethylamine and diethylamine were observed as aliphatic amine products of NDEA degradation in both two processes. They were assumed to arise due to N-N bond fission under UV irradiation, or due to the reaction of NDEA and hydroxyl radicals in the UV/O(3) process.

  5. Effects of microbial utilization of phenolic acids and their phenolic acid breakdown products on allelopathic interactions

    SciTech Connect

    Blum, U.

    1998-04-01

    Reversible sorption of phenolic acids by soils may provide some protection to phenolic acids from microbial degradation. In the absence of microbes, reversible sorption 35 days after addition of 0.5--3 {micro}mol/g of ferulic acid or p-coumaric acid was 8--14% in Cecil A{sub p} horizon and 31--38% in Cecil B{sub t} horizon soil materials. The reversibly sorbed/solution ratios (r/s) for ferulic acid or p-coumaric acid ranged from 0.12 to 0.25 in A{sub p} and 0.65 to 0.85 in B{sub t} horizon soil materials. When microbes were introduced, the r/s ratio for both the A{sub p} and B{sub t} horizon soil materials increased over time up to 5 and 2, respectively, thereby indicating a more rapid utilization of solution phenolic acids over reversibly sorbed phenolic acids. The increase in r/s ratio and the overall microbial utilization of ferulic acid and/or p-coumaric acid were much more rapid in A{sub p} than in B{sub t} horizon soil materials. Reversible sorption, however, provided protection of phenolic acids from microbial utilization for only very short periods of time. Differential soil fixation, microbial production of benzoic acids (e.g., vanillic acid and p-hydroxybenzoic acid) from cinnamic acids (e.g., ferulic acid and p-coumaric acid, respectively), and the subsequent differential utilization of cinnamic and benzoic acids by soil microbes indicated that these processes can substantially influence the magnitude and duration of the phytotoxicity of individual phenolic acids.

  6. Disentangling the interactions between photochemical and bacterial degradation of dissolved organic matter: amino acids play a central role.

    PubMed

    Amado, André M; Cotner, James B; Cory, Rose M; Edhlund, Betsy L; McNeill, Kristopher

    2015-04-01

    Photochemical and bacterial degradation are important pathways to carbon mineralization and can be coupled in dissolved organic matter (DOM) decomposition. However, details of several mechanisms of the coupled photochemical and biological processing of DOM remain too poorly understood to achieve accurate predictions of the impact of these processes on DOM fate and reactivity. The aim of this study was to evaluate how photochemical degradation of amino acids affects bacterial metabolism and whether or not photochemical degradation of DOM competes for amino acids with biological processes. We examined the interactions between photochemical and bacterial degradation dynamics using a mixture of 18 amino acids and examined their dynamics and turnover rates within a larger pool of allochthonous or autochthonous DOM. We observed that photochemical exposure of DOM containing amino acids led to delayed biomass production (even though the final biomass did not differ), most likely due to a need for upregulation of biosynthetic pathways for amino acids that were damaged by photochemically produced reactive oxygen species (ROS). This response was most pronounced in bacterial communities where the abundance of photosensitive amino acids was highest (amended treatments and autochthonous DOM) and least pronounced when the abundance of these amino acids was low (unamended and allochthonous DOM), likely because these bacteria already had these biosynthetic pathways functioning. We observed both a cost and benefit associated with photochemical exposure of DOM. We observed a cost associated with photochemically produced ROS that partially degrade key amino acids and a benefit associated with an increase in the availability of other compounds in the DOM. Bacteria growing on DOM sources that are low in labile amino acids, such as those in terrestrially influenced environments, experience more of the benefits associated with photochemical exposure, whereas bacteria growing in more amino

  7. Malonic acid suppresses mucin-type O-glycan degradation during hydrazine treatment of glycoproteins.

    PubMed

    Goso, Yukinobu

    2016-03-01

    Hydrazine treatment is frequently used for releasing mucin-type O-glycans (O-glycans) from glycoproteins because the method provides O-glycans that retain a reducible GalNAc at their reducing end, which is available for fluorescent labeling. However, many O-glycans are degraded by "peeling" during this treatment. In the current study, it was found that malonic acid suppressed O-glycan degradation during hydrazine treatment of bovine fetuin or porcine gastric mucin in both the gas and liquid phases. This is paradoxical because the release of O-glycans from glycoproteins occurs under alkaline conditions. However, malonic acid seems to prevent the degradation through its acidic property given that other weak acids also prevented the degradation. Accordingly, disodium malonate did not suppress O-glycan degradation. Application of this method to rat gastric mucin demonstrated that the majority of the major O-glycans obtained in the presence of malonic acid were intact, whereas those obtained in the absence of malonic acid were degraded. These results suggest that hydrazine treatment in the presence of malonic acid would allow glycomic analysis of native mucin glycoproteins.

  8. Fate of CL-20 in sandy soils: degradation products as potential markers of natural attenuation.

    PubMed

    Monteil-Rivera, Fanny; Halasz, Annamaria; Manno, Dominic; Kuperman, Roman G; Thiboutot, Sonia; Ampleman, Guy; Hawari, Jalal

    2009-01-01

    Hexanitrohexaazaisowurtzitane (CL-20) is an emerging explosive that may replace the currently used explosives such as RDX and HMX, but little is known about its fate in soil. The present study was conducted to determine degradation products of CL-20 in two sandy soils under abiotic and biotic anaerobic conditions. Biotic degradation was prevalent in the slightly acidic VT soil, which contained a greater organic C content, while the slightly alkaline SAC soil favored hydrolysis. CL-20 degradation was accompanied by the formation of formate, glyoxal, nitrite, ammonium, and nitrous oxide. Biotic degradation of CL-20 occurred through the formation of its denitrohydrogenated derivative (m/z 393 Da) while hydrolysis occurred through the formation of a ring cleavage product (m/z 156 Da) that was tentatively identified as CH(2)=N-C(=N-NO(2))-CH=N-CHO or its isomer N(NO(2))=CH-CH=N-CO-CH=NH. Due to their chemical specificity, these two intermediates may be considered as markers of in situ attenuation of CL-20 in soil.

  9. Fate of CL-20 in sandy soils: degradation products as potential markers of natural attenuation.

    PubMed

    Monteil-Rivera, Fanny; Halasz, Annamaria; Manno, Dominic; Kuperman, Roman G; Thiboutot, Sonia; Ampleman, Guy; Hawari, Jalal

    2009-01-01

    Hexanitrohexaazaisowurtzitane (CL-20) is an emerging explosive that may replace the currently used explosives such as RDX and HMX, but little is known about its fate in soil. The present study was conducted to determine degradation products of CL-20 in two sandy soils under abiotic and biotic anaerobic conditions. Biotic degradation was prevalent in the slightly acidic VT soil, which contained a greater organic C content, while the slightly alkaline SAC soil favored hydrolysis. CL-20 degradation was accompanied by the formation of formate, glyoxal, nitrite, ammonium, and nitrous oxide. Biotic degradation of CL-20 occurred through the formation of its denitrohydrogenated derivative (m/z 393 Da) while hydrolysis occurred through the formation of a ring cleavage product (m/z 156 Da) that was tentatively identified as CH(2)=N-C(=N-NO(2))-CH=N-CHO or its isomer N(NO(2))=CH-CH=N-CO-CH=NH. Due to their chemical specificity, these two intermediates may be considered as markers of in situ attenuation of CL-20 in soil. PMID:18801604

  10. A comparison of the degradation products formed in aerated, aqueous alpha-D-glucose solutions by ultrasound and gamma rays.

    PubMed

    Heusinger, H

    1987-12-01

    The degradation products formed in aerated aqueous alpha-D-glucose solutions by cleavage of the carbon skeleton by ultrasound and gamma irradiation are compared. Common products present for both types of irradiation are: D-glyceraldehyde, D-glyceric acid, hydroxy-malondialdehyde, 2,3-dihydroxy-4-oxo-butanoic acid, tetrodialdose, D-arabinoic acid and D-xylose. 2,3,4-Trihydroxy-5-oxo-pentoic acid and D-arabinose could be detected only by radiolysis and evidence for the formation of 2-hydroxy-3-oxo-pentoic acid was only obtained in sonolysis. These fragmentation products are supposed to be formed by reactions of the glucose-peroxyl radicals with HO2-radicals. Based on the reactions of peroxyl radicals given in the literature, a mechanism is proposed which leads to the observed products.

  11. Fibrinogen Degradation Products and Periodontitis: Deciphering the Connection

    PubMed Central

    2015-01-01

    Introduction Fibrinogen degradation products (e.g. D-dimer) arise from digested fibrin clots and fibrinogen. Elevated concentrations accompany activation of coagulation and fibrinolysis and indicate chronic inflammatory diseases. D-Dimer tests are a quick, noninvasive method to rule out abnormal clotting. Periodontitis strongly affects the haemostatic system and evokes a procoagulant state. Correlation of chronic periodontitis with early indicators of disease (biomarkers) might be useful. Aim The aim of the study was to examine whether the plasma D-dimer concentration reflects the progression of chronic periodontitis and the beneficial effect of periodontal therapy. Materials and Methods Forty randomly selected subjects were divided into four groups, Group I: 10 healthy subjects, Group II: 10 with mild periodontitis, Group III: 10 with moderate periodontitis, Group IV: 10 with severe periodontitis. After thorough dental and periodontal examination, 3 mL of venous blood was collected for measurement of fibrinogen degradation products. Results The patients with moderate and chronic periodontitis exhibited high concentrations of D-dimer (mean value 434.98–535.52 mcg/mL), whereas subjects with mild or no periodontitis exhibited values of 329.78–211.29 mcg/mL. Concentrations of D-dimer were significantly reduced after therapy of all classes of periodontitis. Conclusion Periodontal treatment can reduce amount of D-dimer in the plasma. A higher than normal concentration is observed in chronic periodontitis. PMID:26816985

  12. Mechanistic Study of the Acid Degradation of Lignin Model Compounds

    SciTech Connect

    Sturgeon, M.; Kim, S.; Chmely, S. C.; Foust, T. D.; Beckham, G. T.

    2012-01-01

    Lignin is a major constituent of biomass, which remains underutilized in selective biomass conversion strategies to renewable fuels and chemicals. Here we are interested in understanding the mechanisms related to the acid deconstruction of lignin with a combined theoretical and experimental approach. Two model dimers with a b-O-4 aryl ether linkage (2-phenoxy-1-phenethanol and 2-phenoxy-1-phenyl-1,3 propanediol) and model dimmers with an a-O-4 aryl ether linkage were synthesized and deconstructed in H2SO4. The major products of the acidolysis of the b-O-4 compounds consisted of phenol and two aldehydes, phenylacetaldehyde and benzaldehyde. Quantum mechanical calculations were employed to elucidate possible deconstruction mechanisms with transition state theory. To confirm proposed mechanisms several possible intermediates were studied under similar acidolysis conditions. Although the resonance time for cleavage was on the order several hours, we have shown that the cleavage of the aryl ether linkage affords phenol and aldehydes. We would next like to utilize our mechanism of aryl ether cleavage in actual lignin.

  13. Kinetic evaluation and process performance of an upflow anaerobic filter reactor degrading terephthalic acid.

    PubMed

    Davutluoglu, Orkun I; Seckin, Galip

    2014-01-01

    The anaerobic degradation of terephthalic acid (TA) as the sole organic carbon source was studied in an upflow anaerobic filter (UAF) reactor. The reactor was seeded with biomass obtained from a full-scale upflow anaerobic sludge bed (UASB) reactor and was used to treat wastewater from a petrochemical facility producing dimethyl terephthalate. The UAF reactor was operated for 252 d with a constant hydraulic retention time of 24 h, and the organic loading rate (OLR) was gradually increased from 1 to 10 g-chemical oxygen demand (COD)/L d. After a lag period of approximately 40 d, the COD removal efficiency increased exponentially and high removal rate values (≈90%) were obtained, except for at highest OLR (10 g-COD/L d). The high removal rates and the robustness of the reactor performance could be attributed to the formation of biofilm as well as granular sludge. The methane production rates (0.22 to 2.15 L/d) correlated well with the removed OLRs (0.3 to 6.8 g-COD/L d) during the various phases of treatment, indicating that the main mechanism of TA degradation occurs via methanogenic reactions. The average methane content of the produced biogas was 70.3%. The modified Stover-Kincannon model was found to be applicable for the anaerobic degradation of TA in UAFs (Umax = 64.5, KB = 69.1 g-COD/L d and Ymax = 0.27 L-CH4/g-CODremoved). These results suggest that UAF reactors are among the most effective reactor configurations for the anaerobic degradation of TA.

  14. Use of an acidic Fe/O{sub 2} cell for wastewater treatment: Degradation of aniline

    SciTech Connect

    Brillas, E.; Sauleda, R.; Casado, J.

    1999-12-01

    Solutions containing 0.50 mol dm{sup {minus}3} Na{sub 2}SO{sub 4} and aniline concentrations between 129 and 1,000 ppm have been decontaminated using an acidic Fe/O{sub 2} cell with an Fe anode and a carbon-poly(tetrafluoroethylene) O{sub 2}-fed cathode. This system produces spontaneously strong oxidizing radicals, such as OH{sup {sm{underscore}bullet}} and HO{sub 2}{sup {sm{underscore}bullet}}, which react with pollutants. Decontamination is more efficient for solutions with pH > 3 where intermediates coagulate with the Fe(OH){sub 3} precipitate formed. A 95% degradation is reached after 1 h of treatment of 129 ppm of aniline at initial pH 4 and at 35 C. For higher substrate levels, pollutants are quickly destroyed if the pH is regulated between 4 and 5. After 2 h, solutions up to 500 ppm of aniline are almost completely degraded, whereas 81% of the degradation is reached for 1,000 ppm of substrate. Benzoquinone and nitrobenzene are detected as intermediates. An insignificant accumulation of these products is found in the treatment of 1,000 ppm of substrate, suggesting the formation of polymers that coagulate with the Fe(OH){sub 3} precipitate. Low concentrations of ammonium and nitrate ions have been determined in treated solutions. The major part of the initial carbon and nitrogen is retained in the precipitate, indicating that coagulation of intermediates predominates over their mineralization. A reaction pathway for the degradation of aniline involving all intermediates detected is proposed.

  15. Antagonism between lipid-derived reactive carbonyls and phenolic compounds in the Strecker degradation of amino acids.

    PubMed

    Delgado, Rosa M; Hidalgo, Francisco J; Zamora, Rosario

    2016-03-01

    The Strecker-type degradation of phenylalanine in the presence of 2-pentanal and phenolic compounds was studied to investigate possible interactions that either promote or inhibit the formation of Strecker aldehydes in food products. Phenylacetaldehyde formation was promoted by 2-pentenal and also by o- and p-diphenols, but not by m-diphenols. This is consequence of the ability of phenolic compounds to be converted into reactive carbonyls and produce the Strecker degradation of the amino acid. When 2-pentenal and phenolic compounds were simultaneously present, an antagonism among them was observed. This antagonism is suggested to be a consequence of the ability of phenolic compounds to either react with both 2-pentenal and phenylacetaldehyde, or compete with other carbonyl compounds for the amino acids, a function that is determined by their structure. All these results suggest that carbonyl-phenol reactions may be used to modulate flavor formation produced in food products by lipid-derived reactive carbonyls.

  16. Detoxification of acidic biorefinery waste liquor for production of high value amino acid.

    PubMed

    Christopher, Meera; Anusree, Murali; Mathew, Anil K; Nampoothiri, K Madhavan; Sukumaran, Rajeev Kumar; Pandey, Ashok

    2016-08-01

    The current study evaluates the detoxification of acid pretreatment liquor (APL) using adsorbent (ADS 400 & ADS 800) or ion-exchange (A-27MP & A-72MP) resins and its potential for amino acid production. The APL is generated as a by-product from the pretreatment of lignocellulosic biomass and is rich monomeric sugars as well as sugar degradation products (fermentation inhibitors) such as furfural and hydroxymethyl furfural (HMF). Of the four resins compared, ADS 800 removed approximately 85% and 60% of furfural and HMF, respectively. ADS 800 could be reused for up to six cycles after regeneration without losing its adsorption properties. The study was further extended by assessing the fermentability of detoxified APL for l-lysine production using wild and mutant strains of Corynebacterium glutamicum. The detoxified APL was superior to APL for l-lysine production.

  17. Engineered Production of Short Chain Fatty Acid in Escherichia coli Using Fatty Acid Synthesis Pathway

    PubMed Central

    Jawed, Kamran; Mattam, Anu Jose; Fatma, Zia; Wajid, Saima; Abdin, Malik Z.; Yazdani, Syed Shams

    2016-01-01

    Short-chain fatty acids (SCFAs), such as butyric acid, have a broad range of applications in chemical and fuel industries. Worldwide demand of sustainable fuels and chemicals has encouraged researchers for microbial synthesis of SCFAs. In this study we compared three thioesterases, i.e., TesAT from Anaerococcus tetradius, TesBF from Bryantella formatexigens and TesBT from Bacteroides thetaiotaomicron, for production of SCFAs in Escherichia coli utilizing native fatty acid synthesis (FASII) pathway and modulated the genetic and bioprocess parameters to improve its yield and productivity. E. coli strain expressing tesBT gene yielded maximum butyric acid titer at 1.46 g L-1, followed by tesBF at 0.85 g L-1 and tesAT at 0.12 g L-1. The titer of butyric acid varied significantly depending upon the plasmid copy number and strain genotype. The modulation of genetic factors that are known to influence long chain fatty acid production, such as deletion of the fadD and fadE that initiates the fatty acid degradation cycle and overexpression of fadR that is a global transcriptional activator of fatty acid biosynthesis and repressor of degradation cycle, did not improve the butyric acid titer significantly. Use of chemical inhibitor cerulenin, which restricts the fatty acid elongation cycle, increased the butyric acid titer by 1.7-fold in case of TesBF, while it had adverse impact in case of TesBT. In vitro enzyme assay indicated that cerulenin also inhibited short chain specific thioesterase, though inhibitory concentration varied according to the type of thioesterase used. Further process optimization followed by fed-batch cultivation under phosphorous limited condition led to production of 14.3 g L-1 butyric acid and 17.5 g L-1 total free fatty acid at 28% of theoretical yield. This study expands our understanding of SCFAs production in E. coli through FASII pathway and highlights role of genetic and process optimization to enhance the desired product. PMID:27466817

  18. Engineered Production of Short Chain Fatty Acid in Escherichia coli Using Fatty Acid Synthesis Pathway.

    PubMed

    Jawed, Kamran; Mattam, Anu Jose; Fatma, Zia; Wajid, Saima; Abdin, Malik Z; Yazdani, Syed Shams

    2016-01-01

    Short-chain fatty acids (SCFAs), such as butyric acid, have a broad range of applications in chemical and fuel industries. Worldwide demand of sustainable fuels and chemicals has encouraged researchers for microbial synthesis of SCFAs. In this study we compared three thioesterases, i.e., TesAT from Anaerococcus tetradius, TesBF from Bryantella formatexigens and TesBT from Bacteroides thetaiotaomicron, for production of SCFAs in Escherichia coli utilizing native fatty acid synthesis (FASII) pathway and modulated the genetic and bioprocess parameters to improve its yield and productivity. E. coli strain expressing tesBT gene yielded maximum butyric acid titer at 1.46 g L-1, followed by tesBF at 0.85 g L-1 and tesAT at 0.12 g L-1. The titer of butyric acid varied significantly depending upon the plasmid copy number and strain genotype. The modulation of genetic factors that are known to influence long chain fatty acid production, such as deletion of the fadD and fadE that initiates the fatty acid degradation cycle and overexpression of fadR that is a global transcriptional activator of fatty acid biosynthesis and repressor of degradation cycle, did not improve the butyric acid titer significantly. Use of chemical inhibitor cerulenin, which restricts the fatty acid elongation cycle, increased the butyric acid titer by 1.7-fold in case of TesBF, while it had adverse impact in case of TesBT. In vitro enzyme assay indicated that cerulenin also inhibited short chain specific thioesterase, though inhibitory concentration varied according to the type of thioesterase used. Further process optimization followed by fed-batch cultivation under phosphorous limited condition led to production of 14.3 g L-1 butyric acid and 17.5 g L-1 total free fatty acid at 28% of theoretical yield. This study expands our understanding of SCFAs production in E. coli through FASII pathway and highlights role of genetic and process optimization to enhance the desired product. PMID:27466817

  19. Degradation of Acid Orange 7 Dye in Two Hybrid Plasma Discharge Reactors

    NASA Astrophysics Data System (ADS)

    Shen, Yongjun; Lei, Lecheng; Zhang, Xingwang; Ding, Jiandong

    2014-11-01

    To get an optimized pulsed electrical plasma discharge reactor and to increase the energy utilization efficiency in the removal of pollutants, two hybrid plasma discharge reactors were designed and optimized. The reactors were compared via the discharge characteristics, energy transfer efficiency, the yields of the active species and the energy utilization in dye wastewater degradation. The results showed that under the same AC input power, the characteristics of the discharge waveform of the point-to-plate reactor were better. Under the same AC input power, the two reactors both had almost the same peak voltage of 22 kV. The peak current of the point-to-plate reactor was 146 A, while that of the wire-to-cylinder reactor was only 48.8 A. The peak powers of the point-to-plate reactor and the wire-to-cylinder reactor were 1.38 MW and 1.01 MW, respectively. The energy per pulse of the point-to-plate reactor was 0.2221 J, which was about 29.4% higher than that of the wire-to-cylinder reactor (0.1716 J). To remove 50% Acid Orange 7 (AO7), the energy utilizations of the point-to-plate reactor and the wire-to-cylinder reactor were 1.02 × 10-9 mol/L and 0.61 × 10-9 mol/L, respectively. In the point-to-plate reactor, the concentration of hydrogen peroxide in pure water was 3.6 mmol/L after 40 min of discharge, which was higher than that of the wire-to-cylinder reactor (2.5 mmol/L). The concentration of liquid phase ozone in the point-to-plate reactor (5.7 × 10-2 mmol/L) was about 26.7% higher than that in the wire-to-cylinder reactor (4.5 × 10-2 mmol/L). The analysis results of the variance showed that the type of reactor and reaction time had significant impacts on the yields of the hydrogen peroxide and ozone. The main degradation intermediates of AO7 identified by gas chromatography and mass spectrometry (GCMS) were acetic acid, maleic anhydride, p-benzoquinone, phenol, benzoic acid, phthalic anhydride, coumarin and 2-naphthol. Proposed degradation pathways were

  20. LC-MS/MS structural characterization of stress degradation products including the development of a stability indicating assay of Darunavir: An anti-HIV drug.

    PubMed

    Rao, R Nageswara; Ramachandra, B; Sravan, B; Khalid, Sara

    2014-02-01

    Darunavir, an anti-HIV drug was subjected to forced degradation under acid, base, thermal and neutral hydrolysis, oxidation and photolysis as prescribed by ICH guidelines. Four major degradation products were formed under acid and base hydrolysis, while stable under neutral and thermal hydrolysis, oxidative and photolysis. The drug and its degradation products were separated on Hiber, LiChrospher® 60, RP-select B, C8 column (250mm×4.6mm i.d., 5μm) using 10mM ammonium acetate: acetonitrile (52:48, v/v) as mobile phase in an isocratic elution mode by LC. The degradation products were characterized by LC-MS/MS and fragmentation pathways were proposed. The proposed structures of degradation products were confirmed by HRMS and the LC method was validated with respect to specificity, linearity, accuracy, recovery, LOD and LOQ. PMID:24252722

  1. Degradation of Amino Acids and Structure in Model Proteins and Bacteriophage MS2 by Chlorine, Bromine, and Ozone.

    PubMed

    Choe, Jong Kwon; Richards, David H; Wilson, Corey J; Mitch, William A

    2015-11-17

    Proteins are important targets of chemical disinfectants. To improve the understanding of disinfectant-protein reactions, this study characterized the disinfectant:protein molar ratios at which 50% degradation of oxidizable amino acids (i.e., Met, Tyr, Trp, His, Lys) and structure were observed during HOCl, HOBr, and O3 treatment of three well-characterized model proteins and bacteriophage MS2. A critical question is the extent to which the targeting of amino acids is driven by their disinfectant rate constants rather than their geometrical arrangement. Across the model proteins and bacteriophage MS2 (coat protein), differing widely in structure, methionine was preferentially targeted, forming predominantly methionine sulfoxide. This targeting concurs with its high disinfectant rate constants and supports its hypothesized role as a sacrificial antioxidant. Despite higher HOCl and HOBr rate constants with histidine and lysine than for tyrosine, tyrosine generally was degraded in preference to histidine, and to a lesser extent, lysine. These results concur with the prevalence of geometrical motifs featuring histidines or lysines near tyrosines, facilitating histidine and lysine regeneration upon Cl[+1] transfer from their chloramines to tyrosines. Lysine nitrile formation occurred at or above oxidant doses where 3,5-dihalotyrosine products began to degrade. For O3, which lacks a similar oxidant transfer pathway, histidine, tyrosine, and lysine degradation followed their relative O3 rate constants. Except for its low reactivity with lysine, the O3 doses required to degrade amino acids were as low as or lower than for HOCl or HOBr, indicating its oxidative efficiency. Loss of structure did not correlate with loss of particular amino acids, suggesting the need to characterize the oxidation of specific geometric motifs to understand structural degradation.

  2. Antioxidant activities of fucoidan degraded by gamma irradiation and acidic hydrolysis

    NASA Astrophysics Data System (ADS)

    Lim, Sangyong; Choi, Jong-il; Park, Hyun

    2015-04-01

    Low molecular weight fucoidan, prepared by radical degradation using gamma ray was investigated for its antioxidant activities with different assay methods. As the molecular weight of fucoidan decreased with a higher absorbed dose, ferric-reducing antioxidant power values increased, but β-carotene bleaching inhibition did not change significantly. The antioxidant activity of acid-degraded fucoidan was also examined to investigate the effect of different degradation methods. At the same molecular weight, fucoidan degraded by gamma irradiation showed higher 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity than that observed with the acidic method. This result reveals that in addition to molecular weight, the degradation method affects the antioxidant activity of fucoidan.

  3. Influence of amino acids, buffers, and ph on the γ-irradiation-induced degradation of alginates.

    PubMed

    Ulset, Ann-Sissel T; Mori, Hideki; Dalheim, Marianne Ø; Hara, Masayuki; Christensen, Bjørn E

    2014-12-01

    Alginate-based biomaterials and medical devices are commonly subjected to γ-irradiation as a means of sterilization, either in the dry state or the gel (hydrated) state. In this process the alginate chains degrade randomly in a dose-dependent manner, altering alginates' material properties. The addition of free radical scavenging amino acids such as histidine and phenylalanine protects the alginate significantly against degradation, as shown by monitoring changes in the molecular weight distributions using SEC-MALLS and determining the pseudo first order rate constants of degradation. Tris buffer (0.5 M), but not acetate, citrate, or phosphate buffers had a similar effect on the degradation rate. Changes in pH itself had only marginal effects on the rate of alginate degradation and on the protective effect of amino acids. Contrary to previous reports, the chemical composition (M/G profile) of the alginates, including homopolymeric mannuronan, was unaltered following irradiation up to 10 kGy.

  4. Magnesium degradation products: effects on tissue and human metabolism.

    PubMed

    Seitz, J-M; Eifler, R; Bach, Fr-W; Maier, H J

    2014-10-01

    Owing to their mechanical properties, metallic materials present a promising solution in the field of resorbable implants. The magnesium metabolism in humans differs depending on its introduction. The natural, oral administration of magnesium via, for example, food, essentially leads to an intracellular enrichment of Mg(2+) . In contrast, introducing magnesium-rich substances or implants into the tissue results in a different decomposition behavior. Here, exposing magnesium to artificial body electrolytes resulted in the formation of the following products: magnesium hydroxide, magnesium oxide, and magnesium chloride, as well as calcium and magnesium apatites. Moreover, it can be assumed that Mg(2+) , OH(-) ions, and gaseous hydrogen are also present and result from the reaction for magnesium in an aqueous environment. With the aid of physiological metabolic processes, the organism succeeds in either excreting the above mentioned products or integrating them into the natural metabolic process. Only a burst release of these products is to be considered a problem. A multitude of general tissue effects and responses from the Mg's degradation products is considered within this review, which is not targeting specific implant classes. Furthermore, common alloying elements of magnesium and their hazardous potential in vivo are taken into account.

  5. Forced degradation study of racecadotril: Effect of co-solvent, characterization of degradation products by UHPLC-Q-TOF-MS/MS, NMR and cytotoxicity assay.

    PubMed

    Chiguru, Vishnuvardhan; Lingesh, Allakonda; R, Srinivas; N, Satheeshkumar

    2016-09-01

    Racecadotril, an enkephalinase inhibitor, was subjected to hydrolysis (acidic and alkaline), oxidation, photolysis and thermal stress, as per ICH specified conditions. The drug showed extensive degradation under acidic, basic hydrolysis and oxidative stress conditions whereas, it was stable under other stress conditions. A total of seven degradation products (DPs) were observed. The chromatographic separation was optimized on Acquity HSS Cyano (100×2.1mm, 1.8μ) column using 0.1% formic acid and acetonitrile as mobile phase in gradient mode. Six DPs were characterised by LC-MS/MS and DP1 by GC-MS. The major DPs (DP 2 and DP 5) were isolated and characterised by NMR. This is a typical case of degradation where co solvent methanol reacts with racecadotril leading to the formation of pseudo DPs, DP 6 and DP 5. Interestingly the MS/MS spectra of protonated drug, DP 4 and DP 7 showed product ions which were formed due to intramolecular benzyl migrations. In vitro cytotoxic activity studies on isolated DP 2 and DP 5 revealed that the former has no cytotoxic nature, whereas the latter has potential pulmonary and hepatic toxicity. PMID:27209450

  6. Edible fungus degrade bisphenol A with no harmful effect on its fatty acid composition.

    PubMed

    Zhang, Chengdong; Li, Mingzhu; Chen, Xiaoyan; Li, Mingchun

    2015-08-01

    Bisphenol A (BPA) is an endocrine-disrupting chemical that is ubiquitous in the environment because of its broad industrial use. The authors report that the most widely cultivated mushroom in the world (i.e., white-rot fungus, Pleurotus ostreatus) efficiently degraded 10mg/L of BPA in 7 days. Extracellular laccase was identified as the enzyme responsible for this activity. LC-MS analysis of the metabolites revealed the presence of both low- and high-molecular-weight products obtained via oxidative cleavage and coupling reactions, respectively. In particular, an analysis of the fatty acid composition and chemical structure of the fungal mycelium demonstrated that exposure to BPA resulted in no harmful effects on this edible fungus. The results provide a better understanding of the environmental fate of BPA and its potential impact on food crops. PMID:25933259

  7. Isolation and characterization of a bluegill-degrading microorganism, and analysis of the root hair-promoting effect of the degraded products.

    PubMed

    Sanpa, Sirilak; Sumiyoshi, Sayoko; Kujira, Tadakazu; Matsumiya, Yoshiki; Kubo, Motoki

    2006-02-01

    Bluegill-degrading bacteria were isolated from various environmental sources. Brevibacillus sp. BGM1 degraded bluegill efficiently at 50 degrees C, and its culture supernatant showed the highest peptide and amino acid concentrations as trichloroacetic acid (TCA) soluble fraction (ASF) (10.7 mg/ml) of all supernatants obtained with bluegill as a substrate. Strain BGM1 secreted a protease(s) into the medium, and the concentration of peptides and amino acids gradually increased. The fertile effect of the degraded bluegill products (DGP) on Brassica rapa was also investigated. The root hair density of B. rapa grown with DGP at a concentration of 30 mug peptides and amino acids/ml was about 1.7 times higher than when grown with the same concentration of undegraded bluegill. DGP was shown to increase root hair numbers and adventitious root formation. The results of this study suggest that a specific peptide(s) for promotion of root hair is produced from the order Perciformes with a protease(s) from BGM1.

  8. [Degradation of phytic acid in rapeseed meal by two strains of molds].

    PubMed

    Xiang, W; Zhong, Y

    1998-02-01

    By using selective media, two strains of molds which are able to degrade phytic acid were isolated from soil samples. These molds are able to use inositol as the sole carbon and energy sources for growth. In broth cultures, the degradation rates of phytic acid by these molds were 74.4% and 95.0%, respectively. However, in solid-state fermentation which used rapeseed meal as a raw material, the degradation rate was about 40%. Several metal ions tested were able to enhance the degradation rate of phytic acid. Factors such as temperature, pH and moisture content which affect the growth of molds were also explored. These two strains of molds were initially identified as Paecilomyces sp. and Penicillium sp.. They do not produce any detectable amount of aflatoxins.

  9. Capillary electrophoresis separation of the desamino degradation products of oxytocin.

    PubMed

    Creamer, Jessica S; Krauss, Shannon T; Lunte, Susan M

    2014-02-01

    Oxytocin (OT) is an endogenous and therapeutic hormone necessary for maternal health. It is also the subject of fast growing research in the field of behavioral science. This article describes a rapid CE method using UV detection at 214 nm for the determination of the deamidation products of OT. Deamidation is the most common degradation pathway of peptides and proteins and can lead to reduced therapeutic efficiency of biopharmaceuticals. To achieve a separation of the seven structurally similar desamino peptides from OT, 11 mM sulfobutyl ether β-CD and 10% v/v MeOH were added to a BGE of 50 mM phosphate buffer at pH 6.0. The assay is linear within ≤5-100 μM for all species with a total analysis time of 12 min. The method was then applied to monitor the heat-stress degradation of OT at 70°C, where all seven desamino species were observed over a 96 h period.

  10. Capillary electrophoresis separation of the desamino degradation products of oxytocin

    PubMed Central

    Creamer, Jessica S.; Krauss, Shannon T.; Lunte, Susan M.

    2014-01-01

    Oxytocin is an endogenous and therapeutic hormone necessary for maternal health. It is also the subject of fast growing research in the field of behavioral science. This article describes a rapid capillary electrophoresis method using UV detection at 214 nm for the determination of the deamidation products of oxytocin. Deamidation is the most common degradation pathway of peptides and proteins and can lead to reduced therapeutic efficiency of biopharmaceuticals. To achieve a separation of the seven structurally similar desamino peptides from oxytocin, 11 mM sulfobutyl ether β-cyclodextrin and 10% v/v MeOH were added to a background electrolyte of 50 mM phosphate buffer at pH 6.0. The assay is linear within ≤5-100 μM for all species with a total analysis time of 12 min. The method was then applied to monitor the heat-stress degradation of oxytocin at 70°C, where all seven desamino species were observed over a 96 h period. PMID:24166826

  11. Structural elucidation of two photolytic degradation products of tetrabenazine.

    PubMed

    Bourezg, Zouaoui; Cartiser, Nathalie; Ettouati, Laurent; Guillon, Jean; Lacoudre, Aline; Pinaud, Noël; Le Borgne, Marc; Fessi, Hatem

    2014-03-01

    During solution formulation study of tetrabenazine (TBZ), a dopamine depleting agent, used in chorea associated with Huntington's disease and symptomatic treatment of hyperkinetic movement disorder it was observed a strong discoloration upon storage. We investigated this physico-chemical behavior by implementing forced degradation studies. It was observed yellowing only under Suntest(®) light exposure of TBZ solution. LC-MS (liquid chromatography coupled to mass spectrometer detection) analysis of light exposed TBZ samples allowed us to propose 1,11b-dedihydrotetrabenazine (DTBZ) and 1,3,4,11b-detetrahydrotetrabenazine (TTBZ) as the main TBZ impurities. Synthesis and complete structural determination of DTBZ and TTBZ·HCl by NMR and X-ray crystallography were carried out. They were identical in LC-MS with polar impurities found in light exposed TBZ samples. However, even if these TBZ degradation products are correlated with discoloration of TBZ solution there is no evidence they are directly responsible of it. PMID:24457996

  12. Degradation of oxalic acid by the mycoparasite Coniothyrium minitans plays an important role in interacting with Sclerotinia sclerotiorum.

    PubMed

    Zeng, Li-Mei; Zhang, Jing; Han, Yong-Chao; Yang, Long; Wu, Ming-de; Jiang, Dao-Hong; Chen, Weidong; Li, Guo-Qing

    2014-08-01

    Coniothyrium minitans (Cm) is a mycoparasite of the phytopathogenic fungus Sclerotinia sclerotiorum (Ss). Ss produces a virulence factor oxalic acid (OA) which is toxic to plants and also to Cm, and Cm detoxifies OA by degradation. In this study, two oxalate decarboxylase genes, Cmoxdc1 and Cmoxdc2, were cloned from Cm strain Chy-1. OA and low pH induced expression of Cmoxdc1, but not Cmoxdc2. Cmoxdc1 was partially responsible for OA degradation, whereas Cmoxdc2 had no effect on OA degradation. Disruption of Cmoxdc1 in Cm reduced its ability to infect Ss in dual cultures where OA accumulated. Compared with Chy-1, the Cmoxdc1-disrupted mutants had reduced expression levels of two mycoparasitism-related genes chitinase (Cmch1) and β-1,3-glucanase (Cmg1), and had no detectable activity of extracellular proteases in the presence of OA. On the other hand, the cultural filtrates of the Cmoxdc1-disrupted mutants in OA-amended media showed enhanced antifungal activity, possibly because of increased production of antifungal substances under acidic pH condition resulted from reduced Cmoxdc1-mediated OA degradation. This study provides direct genetic evidence of OA degradation regulating mycoparasitism and antibiosis of Cm against Ss, and sheds light on the sophisticated strategies of Cm in interacting with metabolically active mycelia and dormant sclerotia of Ss. PMID:24467446

  13. Analysis of l-DOPA-derived melanin and a novel degradation product formed under alkaline conditions.

    PubMed

    Omotani, Hidetoshi; Yasuda, Makoto; Ishii, Ritsuko; Ikarashi, Tsukasa; Fukuuchi, Tomoko; Yamaoka, Noriko; Mawatari, Ken-Ichi; Kaneko, Kiyoko; Nakagomi, Kazuya

    2016-06-01

    When the therapeutic drug l-DOPA, which is used to treat Parkinson's disease, is combined with magnesium oxide (MgO), a formulation change produces a dark substance. Infrared spectroscopy reveals that this substance is melanin. After allowing the l-DOPA and MgO mixture to stand, the l-DOPA content decreases significantly, and a new degradation product (the final degradation product of l-DOPA, FDP-D) is generated. Formation of this product requires a solution with a pH of >10, and the presence of MgO is not necessary. FDP-D is not produced by tyrosinase decomposition of l-DOPA and is therefore not a melanin-related compound. Pure FDP-D is isolated by adjusting the l-DOPA solution to pH 10 with ammonium hydroxide, allowing it to stand for 3 days at room temperature, adding trifluoroacetic acid (TFA), filtering the precipitate, and separating the supernatant with high-performance liquid chromatography (HPLC). Mass spectrometry indicates that the isolated FDP-D has a molecular formula of C9H9NO7. On the basis of NMR analysis ((1)H NMR, (13)C NMR, DEPT, H-H COSY, HMQC, and HMBC), FDP-D appears to be a substance with the novel structure 7a-hydroxy-5-oxo-1,2,3,5,7,7a-hexahydropyrano [3,4-b]pyrrole-2,7-dicarboxylic acid. PMID:26999318

  14. Gluconic acid production by Penicillium puberulum.

    PubMed

    Elnaghy, M A; Megalla, S E

    1975-01-01

    Twenty-five Penicillium species isolated from Egyptian soil were examined for their ability to produce gluconic acid in surface culture. Of the eight species capable of producing gluconic acid, Penicillium puberulum gave the maximum yield (91% gluconic acid from glucose after 7 days of fermentation with 3% CaCO3). Peptone was the best nitrogen source for acid fermentation and glucose was superior to sucrose. Addition of low concentrations of KH2PO4 and MgSO4 - 7 H2O stimulated acid production. An initial pH of 6.1 was most favourable for acid accumulation and addition of CaCO3 was necessary for maximum acid production.

  15. Degradation of a model naphthenic acid, cyclohexanoic acid, by vacuum UV (172 nm) and UV (254 nm)/H2O2.

    PubMed

    Drzewicz, Przemysław; Afzal, Atefeh; Gamal El-Din, Mohamed; Martin, Jonathan W

    2010-11-18

    The mechanism of hydroxyl radical initiated degradation of a typical oil sands process water (OSPW) alicyclic carboxylic acid was studied using cyclohexanoic acid (CHA) as a model compound. By use of vacuum ultraviolet irradiation (VUV, 172 nm) and ultraviolet irradiation in the presence of hydrogen peroxide UV(254 nm)/H(2)O(2), it was established that CHA undergoes degradation through a peroxyl radical. In both processes the decay of the peroxyl radical leads predominantly to the formation of 4-oxo-CHA, and minor amounts of hydroxy-CHA (detected only in UV/H(2)O(2)). In UV/H(2)O(2), additional 4-oxo-CHA may also have been formed by direct reaction of the oxyl radical with H(2)O(2). The oxyl radical can be formed during decay of the peroxyl-CHA radical or reaction of hydroxy-CHA with hydroxyl radical. Oxo- and hydroxy-CHA further degraded to various dihydroxy-CHAs. Scission of the cyclohexane ring was also observed, on the basis of the observation of acyclic byproducts including heptadioic acid and various short-chain carboxylic acids. Overall, the hydroxyl radical induced degradation of CHA proceeded through several steps, involving more than one hydroxyl radical reaction, thus efficiency of the UV/H(2)O(2) reaction will depend on the rate of generation of hydroxyl radical throughout the process. In real applications to OSPW, concentrations of H(2)O(2) will need to be carefully optimized and the environmental fate and effects of the various degradation products of naphthenic acids considered.

  16. Evaluation of non-thermal effects of electricity on ascorbic acid and carotenoid degradation in acerola pulp during ohmic heating.

    PubMed

    Jaeschke, Débora Pez; Marczak, Ligia Damasceno Ferreira; Mercali, Giovana Domeneghini

    2016-05-15

    The effect of electric field on ascorbic acid and carotenoid degradation in acerola pulp during ohmic heating was evaluated. Ascorbic acid kinetic degradation was evaluated at 80, 85, 90 and 95°C during 60 min of thermal treatment by ohmic and conventional heating. Carotenoid degradation was evaluated at 90 and 95°C after 50 min of treatment. The different temperatures evaluated showed the same effect on degradation rates. To investigate the influence of oxygen concentration on the degradation process, ohmic heating was also carried out under rich and poor oxygen modified atmospheres at 90°C. Ascorbic acid and carotenoid degradation was higher under a rich oxygen atmosphere, indicating that oxygen is the limiting reagent of the degradation reaction. Ascorbic acid and carotenoid degradation was similar for both heating technologies, demonstrating that the presence of the oscillating electric field did not influence the mechanisms and rates of reactions associated with the degradation process. PMID:26775953

  17. Evaluation of non-thermal effects of electricity on ascorbic acid and carotenoid degradation in acerola pulp during ohmic heating.

    PubMed

    Jaeschke, Débora Pez; Marczak, Ligia Damasceno Ferreira; Mercali, Giovana Domeneghini

    2016-05-15

    The effect of electric field on ascorbic acid and carotenoid degradation in acerola pulp during ohmic heating was evaluated. Ascorbic acid kinetic degradation was evaluated at 80, 85, 90 and 95°C during 60 min of thermal treatment by ohmic and conventional heating. Carotenoid degradation was evaluated at 90 and 95°C after 50 min of treatment. The different temperatures evaluated showed the same effect on degradation rates. To investigate the influence of oxygen concentration on the degradation process, ohmic heating was also carried out under rich and poor oxygen modified atmospheres at 90°C. Ascorbic acid and carotenoid degradation was higher under a rich oxygen atmosphere, indicating that oxygen is the limiting reagent of the degradation reaction. Ascorbic acid and carotenoid degradation was similar for both heating technologies, demonstrating that the presence of the oscillating electric field did not influence the mechanisms and rates of reactions associated with the degradation process.

  18. Energetics and kinetics of anaerobic aromatic and fatty acid degradation

    SciTech Connect

    McInerney, M.J.

    1992-11-16

    The kinetics of benzoate degradation by the anaerobic syntrophic bacterium, Syntrophus buswellii, was studied in coculture with Desulfovibrio strain G11. The threshold value for benzoate degradation was dependent on the acetate concentration with benzoate threshold values ranging from 2.4 [mu]M at 20 mM acetate to 30.0 [mu]M at 65 mM acetate. Increasing acetate concentrations also inhibited the rate of benzoate degradation with a apparent K[sub i] for acetate inhibition of 7.0 mM. Lower threshold values were obtained when nitrate rather than sulfate was the terminal electron acceptor. These data are consistent with a thermodynamic explanation for the threshold, and suggest that there is a minimum Gibbs free energy value required for the degradation of benzoate. An acetoacetyl-CoA thiolase has been isolated from Syntrophomonas wolfei; it is apparently a key enzyme controlling the synthesis of poly-B-hydroxyalkanoate from acetyl-CoA in this organism. Kinetic characterization of the acetoacetyl-CoA thiolase from S. wolfei showed that it is similar in its structural, kinetic, and apparent regulatory properties to other biosynthetic acetoacetyl-CoA thiolases from phylogenetically distinct bacteria that synthesize PHA. Intracellular concentrations of CoA and acetyl-CoA are believed to be critical factors regulating the activity of the acetoacetyl-CoA thiolase in S. wolfei. We have also isolated and characterized several new halophilic anaerobic fermentative anaerobes. Phylogenetic analysis indicates that one of these bacteria is a new species in the genus, Haloanaerobium. Two other species appear to be members of the genus, Halobacteroides. Several halophilic acetoclastic methanogenic bacteria have also been isolated and their physiological properties are currently under investigation. We have also isolated an acetate-using dissimilatory iron-reducing bacterium.

  19. Modelling the degradation and elastic properties of poly(lactic-co-glycolic acid) films and regular open-cell tissue engineering scaffolds.

    PubMed

    Shirazi, Reyhaneh Neghabat; Ronan, William; Rochev, Yury; McHugh, Peter

    2016-02-01

    Scaffolding plays a critical rule in tissue engineering and an appropriate degradation rate and sufficient mechanical integrity are required during degradation and healing of tissue. This paper presents a computational investigation of the molecular weight degradation and the mechanical performance of poly(lactic-co-glycolic acid) (PLGA) films and tissue engineering scaffolds. A reaction-diffusion model which predicts the degradation behaviour is coupled with an entropy-based mechanical model which relates Young׳s modulus and the molecular weight. The model parameters are determined based on experimental data for in-vitro degradation of a PLGA film. Microstructural models of three different scaffold architectures are used to investigate the degradation and mechanical behaviour of each scaffold. Although the architecture of the scaffold does not have a significant influence on the degradation rate, it determines the initial stiffness of the scaffold. It is revealed that the size of the scaffold strut controls the degradation rate and the mechanical collapse. A critical length scale due to competition between diffusion of degradation products and autocatalytic degradation is determined to be in the range 2-100μm. Below this range, slower homogenous degradation occurs; however, for larger samples monomers are trapped inside the sample and faster autocatalytic degradation occurs.

  20. Enzymatic degradation of plutonium-contaminated cellulose products

    SciTech Connect

    Heintz, C.E.; Rainwater, K.A.; Swift, L.M.; Barnes, D.L.; Worl, L.A.

    1999-06-01

    Enzyme solutions produced for commercial purposes unrelated to waste management have the potential for reducing the volume of wastes in streams containing cellulose, lipid and protein materials. For example, the authors have shown previously that cellulases used in denim production and in detergent formulations are able to digest cellulose-containing sorbents and other cellulose-based wastes contaminated either with crude oil or with uranium. This presentation describes the use of one such enzyme preparation (Rapidase{trademark}, manufactured by Genencor, Rochester, NY) for the degradation of cotton sorbents intentionally contaminated with low levels of plutonium. This is part of a feasibility study to determine if such treatments have a role in reducing the volume of low level and transuranic wastes to minimize the amount of radionuclide-contaminated waste destined for costly disposal options.

  1. Enzymatic degradation of plutonium-contaminated cellulose products

    SciTech Connect

    Heintz, C.E.; Rainwater, K.A.; Swift, L.M.; Barnes, D.L.; Worl, L.; Avens, L.

    1999-03-01

    Enzyme solutions produced for commercial purposes unrelated to waste management have the potential for reducing the volume of wastes in streams containing cellulose, lipid and protein materials. For example, the authors have shown that cellulases used in denim production and in detergent formulations are able to digest cellulose-containing sorbents and other cellulose-based wastes contaminated either with crude oil or with radionuclides. This presentation describes the use of one such enzyme preparation (Rapidase{trademark}) for the degradation of cotton sorbents intentionally contaminated with low levels of plutonium. This is part of a feasibility study to determine if such treatments have a role in reducing the volume of low level and transuranic wastes to minimize the amount of radionuclide-contaminated waste that must be disposed of in secured storage areas.

  2. Selective microbial degradation of saturated methyl branched chain fatty acid isomers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Three strains of Pseudomonas bacteria were screened for their capabilities of degrading chemically synthesized saturated branched-chain fatty acids (sbc-FAs). Mixtures of sbc-FAs with the methyl-branch located at various locales along the fatty acid were used as a carbon feedstock in shake-flask cu...

  3. Phospholipid End-Capped Acid-Degradable Polyurethane Micelles for Intracellular Delivery of Cancer Therapeutics.

    PubMed

    John, Johnson V; Thomas, Reju George; Lee, Hye Ri; Chen, Hongyu; Jeong, Yong Yeon; Kim, Il

    2016-08-01

    Nanoscale drug carriers fabricated by phospholipid end-capped polyurethane bearing acetal backbones that degrade in acidic conditions are fabricated. These micelles effectively allow drugs to enter the blood circulation, and then disintegrate in acidic endosomes and lysosomes for intelligent delivery of payloads. PMID:27245616

  4. A study on degradation kinetics of ascorbic acid in amla (Phyllanthus emblica L.) during cooking.

    PubMed

    Nisha, P; Singhal, Rekha S; Pandit, Aniruddha B

    2004-08-01

    The kinetics of ascorbic acid degradation in amla (Phyllanthus emblica L.) as well as in pure ascorbic acid solutions at initial concentrations present in amla over a temperature range of 50-120 degrees C (steady-state temperature) has been studied. The ascorbic acid degradation followed first-order reaction kinetics where the rate constant increased with an increase in temperature. The temperature dependence of degradation was adequately modeled by the Arrhenius equation. The activation energies were found to be 4.09 kcal/mole for amla and 4.49 kcal/mole for pure vitamin solution. The degradation kinetics of ascorbic acid was also evaluated in normal open pan cooking, pressure-cooking and a newly developed and patented fuel-efficient EcoCooker (unsteady state heating process). A mathematical model was developed using the steady-state kinetic parameters obtained to predict the losses of ascorbic acid from the time-temperature data of the unsteady state heating processing method. The results obtained indicate the ascorbic acid degradation is of a similar order of magnitude in all the methods of cooking.

  5. Identification and characterization of stressed degradation products of metoprolol using LC/Q-TOF-ESI-MS/MS and MS(n) experiments.

    PubMed

    Borkar, Roshan M; Raju, B; Srinivas, R; Patel, Prashant; Shetty, Satheesh Kumar

    2012-06-01

    A rapid, specific and reliable isocratic high-performance liquid chromatography combined with quadrupole time-of-flight electrospray ionization tandem mass spectrometry (LC/Q-TOF-ESI-MS/MS) method has been developed and validated for the identification and characterization of stressed degradation products of metoprolol. Metoprolol, an anti-hypertensive drug, was subjected to hydrolysis (acidic, alkaline and neutral), oxidation, photolysis and thermal stress, as per ICH-specified conditions. The drug showed extensive degradation under oxidative and hydrolysis (acid and base) stress conditions. However, it was stable to thermal, neutral and photolysis stress conditions. A total of 14 degradation products were observed and the chromatographic separation of the drug and its degradation products was achieved on a C(18) column (4.6 × 250 mm, 5 µm). To characterize degradation products, initially the mass spectral fragmentation pathway of the drug was established with the help of MS/MS, MS(n) and accurate mass measurements. Similarly, fragmentation pattern and accurate masses of the degradation products were established by subjecting them to LC-MS/QTOF analysis. Structure elucidation of degradation products was achieved by comparing their fragmentation pattern with that of the drug. The degradation products DP(2) (m/z 153) and DP(14) (m/z 236) were matched with impurity B, listed in European Pharmacopoeia and British Pharmacopoeia, and impurity I, respectively. The LC-MS method was validated with respect to specificity, linearity, accuracy and precision.

  6. Sonophotolytic degradation of phthalate acid esters in water and wastewater: influence of compound properties and degradation mechanisms.

    PubMed

    Xu, L J; Chu, W; Graham, Nigel

    2015-05-15

    The influence of physicochemical properties on the sonolytic and sonophotolytic degradation of a group of short-chain phthalate acid esters (PAEs) was investigated in this study. A 400 kHz ultrasonic system and a photolytic system at 253.7 nm were employed separately and together, and both pure water and secondary effluent were used as the water matrices. It was found that PAEs with greater hydrophobicity demonstrated more rapid sonolysis and exhibited greater competitiveness in sonochemical reactions in the presence of other compounds. However, although a greater compound hydrophobicity is beneficial for the sonochemical degradation of PAEs, the observed synergy between ultrasound and UV in the sonophotolytic process is reduced owing to the lower accumulation of H₂O₂ in the aqueous phase. For the sonophotolysis of PAEs in secondary effluent, it was found that PAEs with greater hydrophobicity experienced less inhibition or competition from the background organic substances (expressed as TOC). Identification of prominent degradation intermediates of di-n-butyl phthalate (DBP), as a representative PAE, indicated that hydroxylation of the aromatic ring and butyl-scission of the aliphatic chain are the principal degradation mechanisms. The combined process of US/UV produced a greater degree of DBP mineralization than either US or UV alone (17% TOC reduction within 90 min).

  7. Electrochemical assisted photocatalytic degradation of salicylic acid with highly ordered TiO2 nanotube electrodes

    NASA Astrophysics Data System (ADS)

    Zhang, Qian; Zhu, Jinwei; Wang, Ying; Feng, Jiangtao; Yan, Wei; Xu, Hao

    2014-07-01

    To explore the kinetics of photoelectrocatalytic degradation of salicylic acid, one of the important PPCPs, highly ordered TiO2 nanotube arrays (NTs) were prepared by the electrochemical anodization and characterized with scanning electron microscopy and X-ray diffraction techniques. The effect of TiO2 NTs properties, bias potential, initial salicylic acid concentration and solution pH on the degradation efficiency was studied and carefully analyzed. The results revealed that the salicylic acid degradation follows quasi-first order kinetics in the photoelectrocatalytic process, and the fastest decay kinetics was achieved in acidic environment (pH 2). The result was further interpreted through the electrochemical impedance spectroscopy. It is confirmed that the electrochemical assisted photocatalysis is a synergetic approach to combat stable organic substances with improved efficiency.

  8. Transgenic production of arachidonic acid in oilseeds.

    PubMed

    Petrie, James R; Shrestha, Pushkar; Belide, Srinivas; Mansour, Maged P; Liu, Qing; Horne, James; Nichols, Peter D; Singh, Surinder P

    2012-02-01

    We describe a transgenic microalgal Δ9-elongase pathway transformed in both Brassica napus and Arabidopsis thaliana seed resulting in the production of arachidonic acid (ARA). This pathway is noteworthy for both the production of ARA in seed tissue and the low levels of intermediate C20 fatty acids that accumulate. We also demonstrate that the arachidonic acid is naturally enriched at the sn2 position in triacylglycerol. This is the first report of ARA production by the Δ9-elongase pathway in an oilseed.

  9. Identifying high production, low production and degraded rangelands in Senegal with normalized difference vegetation index data

    USGS Publications Warehouse

    Tappan, G. Gray; Wood, Lynette; Moore, Donald G.

    1993-01-01

    Seasonal herbaceous vegetation production on Senegal's native rangelands exhibits high spatial and temporal variability. This variability can be monitored using normalized difference vegetation index (NDVI) data computed from 1-km resolution Advanced Very High Resolution Radiometer (AVHRR) image data. Although annual fluctuations in rainfall account for some of the variability, numerous long-term production patterns are evident in the AVHRR time-series data. Different n productivity reflect variations in the region's climate, topography, soils, and land use. Areas of overgrazing and intensive cultivation have caused long-term soil and vegetation degradation. Rangelands of high and low productivity, and degraded rangelands were identified using NDVI. Time-series image data from 1987 though 1992 were used to map relative rangeland productivity. The results were compared to detailed resource maps on soils, vegetation and land use. Much of the variation in rangeland productivity correlated well to the known distribution of resources. The study developed an approach that identified a number of areas of degraded soils and low vegetation production.

  10. Citric Acid Fuctionalized Magnetic Ferrite Nanoparticles for Photocatalytic Degradation of Azo Dye.

    PubMed

    Mahto, Triveni Kumar; Roy, Anurag; Sahoo, Banalata; Sahu, Sumanta Kumar

    2015-01-01

    In this study different magnetic ferrite nanoparticles (MFe2O4, where M = Fe, Mn, Zn) were synthesized through an aqueous coprecipitation method and then functionalized with citric acid for the degradation of azo dye present in industrial waste water. Here we evaluated the role of citric acid for photocatalytic application. The synthesized nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and the catalytic activity in degradation of methyl orange (MO) was evaluated. The rate of MO degradation in different magnetic systems was determined by UV-Vis spectroscopy. The effect of active parameters (pH, initial MO concentration and effect of sunlight) on degradation performance was investigated. For the first time, citric acid chemistry is successfully exploited to develop a photocatalyst that can successfully degrade the dyes. This citric acid functionalized magnetic ferrite nanoparticles are very much effective for photocalytic degradation of dye and also these can be recollected with the help of permanent magnet for successive uses.

  11. 40 CFR 721.10679 - Carboxylic acid, substituted alkylstannylene ester, reaction products with inorganic acid tetra...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... alkylstannylene ester, reaction products with inorganic acid tetra alkyl ester (generic). 721.10679 Section 721... Carboxylic acid, substituted alkylstannylene ester, reaction products with inorganic acid tetra alkyl ester... identified generically as carboxylic acid, substituted alkylstannylene ester, reaction products...

  12. Carbon capture and sequestration: an exploratory inhalation toxicity assessment of amine-trapping solvents and their degradation products.

    PubMed

    McDonald, Jacob D; Kracko, Dean; Doyle-Eisele, Melanie; Garner, C Edwin; Wegerski, Chris; Senft, Al; Knipping, Eladio; Shaw, Stephanie; Rohr, Annette

    2014-09-16

    Carbon dioxide (CO2) absorption with aqueous amine solvents is a method of carbon capture and sequestration (CCS) from flue gases. One concern is the possible release of amine solvents and degradation products into the atmosphere, warranting evaluation of potential pulmonary effects from inhalation. The CCS amines monoethanolamine (MEA), methyldiethanolamine (MDEA), and piperazine (PIP) underwent oxidative and CO2-mediated degradation for 75 days. C57bl/6N mice were exposed for 7 days by inhalation of 25 ppm neat amine or equivalant concentration in the degraded mixture. The aqueous solutions were nebulized to create the inhalation atmospheres. Pulmonary response was measured by changes in inflammatory cells in bronchoalveolar lavage fluid and cytokine expression in lung tissue. Ames mutagenicity and CHO-K1 micronucleus assays were applied to assess genotoxicity. Chemical analysis of the test atmosphere and liquid revealed complex mixtures, including acids, aldehydes, and other compounds. Exposure to oxidatively degraded MEA increased (p < 0.05) total cells, neutrophils, and lymphocytes compared to control mice and caused inflammatory cytokine expression (statistical increase at p < 0.05). MEA and CO2-degraded MEA were the only atmospheres to show statistical (p < 0.05) increase in oxidative stress. CO2 degradation resulted in a different composition, less degradation, and lower observed toxicity (less magnitude and number of effects) with no genotoxicity. Overall, oxidative degradation of the amines studied resulted in enhanced toxicity (increased magnitude and number of effects) compared to the neat chemicals.

  13. Degradation of carbamazepine by UV/chlorine advanced oxidation process and formation of disinfection by-products.

    PubMed

    Zhou, Shiqing; Xia, Ying; Li, Ting; Yao, Tian; Shi, Zhou; Zhu, Shumin; Gao, Naiyun

    2016-08-01

    Pharmaceuticals in water are commonly found and are not efficiently removed by current treatment processes. Degradation of antiepileptic drug carbamazepine (CBZ) by UV/chlorine advanced oxidation process was systematically investigated in this study. The results showed that the UV/chlorine process was more effective at degrading CBZ than either UV or chlorination alone. The CBZ degradation followed pseudo-first order reaction kinetics, and the degradation rate constants (kobs) were affected by the chlorine dose, solution pH, and natural organic matter concentration to different degrees. Degradation of CBZ greatly increased with increasing chlorine dose and decreasing solution pH during the UV/chlorine process. Additionally, the presence of natural organic matter in the solution inhibited the degradation of CBZ. UV photolysis, chlorination, and reactive species (hydroxyl radical •OH and chlorine atoms •Cl) were identified as responsible for CBZ degradation in the UV/chlorine process. Finally, a degradation pathway for CBZ in the UV/chlorine process was proposed and the formation potentials of carbonaceous and nitrogenous disinfection by-products were evaluated. Enhanced formation of trichloroacetic acid, dichloroacetonitrile, and trichloronitromethane precursors should be considered when applying UV/chlorine advanced oxidation process to drinking water. PMID:27164884

  14. Identification of degradation products of thiram in water, soil and plants using LC-MS technique.

    PubMed

    Gupta, Bina; Rani, Manviri; Kumar, Rahul; Dureja, Prem

    2012-09-01

    In order to evaluate the deleterious effects of exposure to pesticides on a target population, a comprehensive study on their degradation in the various segments of ecosystem under varying environmental conditions is needed. In view of this, a study has been carried out on the metabolic pathways of thiram, a dithiocarbamate fungicide, in a variety of matrices namely water and soil under controlled conditions and plants in field conditions. The identification of degradation products was carried out in samples collected at various time points using LC-MS. The degradation products identified can be rationalized as originating by a variety of processes like hydrolysis, oxidation, N-dealkylation and cyclization. As a result of these processes the presence of some metabolites like dimethyl dithiocarbamate, bis(dimethyl carbamoyl) disulphide, bis(dimethyl dithiocarbamoyl) trisulphide and N-methyl-amino-dithiocarbamoyl sulphide was observed in all the cases. However, some different metabolites were observed with the change in the matrix or its characteristics such as cyclised products 2(N, N-dimethyl amino)thiazoline carboxylic acid and 2-thioxo-4-thiazolidine were observed only in plants. The investigations reflect that degradation initiates with hydrolysis, subsequently oxidation/dealkylation, followed by different types of reactions. The pathways seem to be complex and dependent on the matrices. Dimethyl dithiocarbamate and oxon metabolites, which are more toxic than parent compound, seem to persist for a longer time. Results indicate persistence vis-a-vis toxicity of pesticide and its metabolites and also provide a data bank of metabolites for forensic and epidemiological investigations.

  15. Kinetics of the thermal degradation of patulin in the presence of ascorbic acid.

    PubMed

    Kokkinidou, S; Floros, J D; LaBorde, L F

    2014-01-01

    Degradation of the mycotoxin patulin between 25 and 85 °C without and with added ascorbic acid was studied, and the effectiveness of linear and nonlinear models for predicting reaction rates was compared. In agreement with previous reports, ascorbic acid significantly increased (P ≤ 0.05) the rate of patulin degradation at all temperatures studied. The data for patulin degradation in the absence of ascorbic acid were adequately modeled using a zero-order linear kinetic model. However, the predictive abilities of zero and higher-order linear models were not adequate to describe the more complex reactions that likely occurred when ascorbic acid was added. In contrast, the nonlinear Weibull model adequately described the patulin-ascorbic acid reaction throughout the temperature range studied. Zero-order rate constants and Weibull scale values for each of the respective reactions followed the Arrhenius law. Activation energies of 58.7 ± 3.9 and 29.6 ± 1.9 kJ mol⁻¹ for the reaction without and with ascorbic acid, respectively, confirmed decreased patulin stability in the presence of ascorbic acid and suggested that the mechanisms for the 2 degradation reactions were different.

  16. Characterization of bacterial diversity in an atrazine degrading enrichment culture and degradation of atrazine, cyanuric acid and biuret in industrial wastewater.

    PubMed

    Dutta, Anirban; Vasudevan, Venugopal; Nain, Lata; Singh, Neera

    2016-01-01

    An enrichment culture was used to study atrazine degradation in mineral salt medium (MSM) (T1), MSM+soil extract (1:1, v/v) (T2) and soil extract (T3). Results suggested that enrichment culture required soil extract to degrade atrazine, as after second sequential transfer only partial atrazine degradation was observed in T1 treatment while atrazine was completely degraded in T2 and T3 treatments even after fourth transfer. Culture independent polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) technique confirmed selective enrichment of genus Bacillus along with Pseudomonas and Burkholderia. Degradation of atrazine/metabolites in the industrial wastewater was studied at different initial concentrations of the contaminants [wastewater-water (v/v) ratio: T1, 1:9; T2, 2:8; T3, 3:7; T4, 5:5 and T5, undiluted effluent]. The initial concentrations of atrazine, cyanuric acid and biuret ranged between 5.32 and 53.92 µg mL(-1), 265.6 and 1805.2 µg mL(-1) and 1.85 and 16.12 µg mL(-1), respectively. The enrichment culture was able to completely degrade atrazine, cyanuric acid and biuret up to T4 treatment, while no appreciable degradation of contaminants was observed in the undiluted effluent (T5). Inability of enrichment culture to degrade atrazine/metabolites might be due to high concentrations of cyanuric acid. Therefore, a separate study on cyanuric acid degradation suggested: (i) no appreciable cyanuric acid degradation with accumulation of an unidentified metabolite in the medium where cyanuric acid was supplemented as the sole source of carbon and nitrogen; (ii) partial cyanuric acid degradation with accumulation of unidentified metabolite in the medium containing additional nitrogen source; and (iii) complete cyanuric acid degradation in the medium supplemented with an additional carbon source. This unidentified metabolite observed during cyanuric acid degradation and also detected in the enrichment culture inoculated wastewater samples

  17. Characterization of bacterial diversity in an atrazine degrading enrichment culture and degradation of atrazine, cyanuric acid and biuret in industrial wastewater.

    PubMed

    Dutta, Anirban; Vasudevan, Venugopal; Nain, Lata; Singh, Neera

    2016-01-01

    An enrichment culture was used to study atrazine degradation in mineral salt medium (MSM) (T1), MSM+soil extract (1:1, v/v) (T2) and soil extract (T3). Results suggested that enrichment culture required soil extract to degrade atrazine, as after second sequential transfer only partial atrazine degradation was observed in T1 treatment while atrazine was completely degraded in T2 and T3 treatments even after fourth transfer. Culture independent polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) technique confirmed selective enrichment of genus Bacillus along with Pseudomonas and Burkholderia. Degradation of atrazine/metabolites in the industrial wastewater was studied at different initial concentrations of the contaminants [wastewater-water (v/v) ratio: T1, 1:9; T2, 2:8; T3, 3:7; T4, 5:5 and T5, undiluted effluent]. The initial concentrations of atrazine, cyanuric acid and biuret ranged between 5.32 and 53.92 µg mL(-1), 265.6 and 1805.2 µg mL(-1) and 1.85 and 16.12 µg mL(-1), respectively. The enrichment culture was able to completely degrade atrazine, cyanuric acid and biuret up to T4 treatment, while no appreciable degradation of contaminants was observed in the undiluted effluent (T5). Inability of enrichment culture to degrade atrazine/metabolites might be due to high concentrations of cyanuric acid. Therefore, a separate study on cyanuric acid degradation suggested: (i) no appreciable cyanuric acid degradation with accumulation of an unidentified metabolite in the medium where cyanuric acid was supplemented as the sole source of carbon and nitrogen; (ii) partial cyanuric acid degradation with accumulation of unidentified metabolite in the medium containing additional nitrogen source; and (iii) complete cyanuric acid degradation in the medium supplemented with an additional carbon source. This unidentified metabolite observed during cyanuric acid degradation and also detected in the enrichment culture inoculated wastewater samples

  18. Methods of Analysis by the U.S. Geological Survey Organic Geochemistry Research Group-Determination of Dissolved Isoxaflutole and Its Sequential Degradation Products, Diketonitrile and Benzoic Acid, in Water Using Solid-Phase Extraction and Liquid Chromatography/Tandem Mass Spectrometry

    USGS Publications Warehouse

    Meyer, Michael T.; Lee, Edward A.; Scribner, Elisabeth A.

    2007-01-01

    An analytical method for the determination of isoxaflutole and its sequential degradation products, diketonitrile and a benzoic acid analogue, in filtered water with varying matrices was developed by the U.S. Geological Survey Organic Geochemistry Research Group in Lawrence, Kansas. Four different water-sample matrices fortified at 0.02 and 0.10 ug/L (micrograms per liter) are extracted by vacuum manifold solid-phase extraction and analyzed by liquid chromatography/tandem mass spectrometry using electrospray ionization in negative-ion mode with multiple-reaction monitoring (MRM). Analytical conditions for mass spectrometry detection are optimized, and quantitation is carried out using the following MRM molecular-hydrogen (precursor) ion and product (p) ion transition pairs: 357.9 (precursor), 78.9 (p), and 277.6 (p) for isoxaflutole and diketonitrile, and 267.0 (precursor), 159.0 (p), and 223.1 (p) for benzoic acid. 2,4-dichlorophenoxyacetic acid-d3 is used as the internal standard, and alachlor ethanesulfonic acid-d5 is used as the surrogate standard. Compound detection limits and reporting levels are calculated using U.S. Environmental Protection Agency procedures. The mean solid-phase extraction recovery values ranged from 104 to 108 percent with relative standard deviation percentages ranging from 4.0 to 10.6 percent. The combined mean percentage concentration normalized to the theoretical spiked concentration of four water matrices analyzed eight times at 0.02 and 0.10 ug/L (seven times for the reagent-water matrix at 0.02 ug/L) ranged from approximately 75 to 101 percent with relative standard deviation percentages ranging from approximately 3 to 26 percent for isoxaflutole, diketonitrile, and benzoic acid. The method detection limit (MDL) for isoxaflutole and diketonitrile is 0.003 ug/L and 0.004 ug/L for benzoic acid. Method reporting levels (MRLs) are 0.011, 0.010, and 0.012 ug/L for isoxaflutole, diketonitrile, and benzoic acid, respectively. On the basis

  19. Degradability of fluorapatite-leucite ceramics in naturally acidic agents.

    PubMed

    Kukiattrakoon, Boonlert; Hengtrakool, Chanothai; Kedjarune-Leggat, Ureporn

    2010-10-01

    This study was conducted to evaluate the titratable acidity and effect of naturally acidic agents on the surface microhardness, elemental composition, and surface morphology of fluorapatite-leucite ceramics. One hundred and ten ceramic disks (IPS d.SIGN), 12.0 mm in diameter and 2.0 mm in thickness, were fabricated. Before immersion, the baseline data of Vickers microhardness and elemental composition were recorded. Four groups were immersed in acidic agents (citrate buffer solution, green mango juice, and pineapple juice) and deionized water (control) at 37ºC for 168 hours, whereas one group was immersed in 4% acetic acid at 80ºC for 168 hours. After immersion, specimens were evaluated and data were analyzed using one-way repeated ANOVA and Tukey's test (α=0.05). Microhardness values significantly decreased after immersion (p<0.05). In terms of elemental composition, the weight percentages of silicon, potassium, aluminum, and sodium also decreased after immersion (p<0.05). Results of this study showed that fluorapatite-leucite ceramics were affected by long-term immersion in acidic agents.

  20. Characterization of a new degradation product of nifedipine formed on catalysis by atenolol: A typical case of alteration of degradation pathway of one drug by another.

    PubMed

    Handa, Tarun; Singh, Saranjit; Singh, Inder Pal

    2014-02-01

    An increasing interest is being shown throughout the world on the use of fixed-dose combinations of drugs in the therapy of select diseases, like cardiovascular diseases, due to their multiple advantages. Though the main criterion for combining drugs in a single dosage form is the rationale, but consideration like stability of formulation is equally important, due to an added aspect of drug-drug interaction. The objective of this study was to evaluate interaction among the drugs in an antihypertensive combination of nifedipine and atenolol. Nifedipine is a known light sensitive drug, which degrades via intra-molecular mechanisms to nitro- and nitroso-pyridine analogs, along with a few minor secondary products that are formed through inter-molecular interactions amongst primary degradation products and their intermediates. Atenolol is reasonably stable weakly basic drug that is mainly hydrolyzed at acetamide terminal amide moiety to its corresponding carboxylic acid. To the best of our knowledge, there is no known information on chemical compatibility among the two drugs. The present study involved subjecting of nifedipine, atenolol and their combination to a variety of accelerated and stress conditions. HPLC studies revealed formation of a new product in the mixture of two drugs (∼2%), which was also generated from nifedipine alone, but at trace levels (<0.1%). The product was isolated by preparative chromatography and subjected to indepth studies for its characterization. Ultra-violet, FT-IR, mass spectrometric and nuclear magnetic resonance spectroscopic studies highlighted that the principal photo-degradation pathway of nifedipine was modified and diverted in the presence of atenolol. To verify the same, a study was conducted employing two other β-blockers with similar structures to atenolol, and the same product was formed in relatively higher quantity therein also. The new product is postulated to be produced as a result of rearrangement of hydroxylamine

  1. Transformation efficiency and formation of transformation products during photochemical degradation of TCE and PCE at micromolar concentrations

    PubMed Central

    2014-01-01

    Background Trichloroethene and tetrachloroethene are the most common pollutants in groundwater and two of the priority pollutants listed by the U.S. Environmental Protection Agency. In previous studies on TCE and PCE photolysis and photochemical degradation, concentration ranges exceeding environmental levels by far with millimolar concentrations of TCE and PCE have been used, and it is not clear if the obtained results can be used to explain the degradation of these contaminants at more realistic environmental concentration levels. Methods Experiments with micromolar concentrations of TCE and PCE in aqueous solution using direct photolysis and UV/H2O2 have been conducted and product formation as well as transformation efficiency have been investigated. SPME/GC/MS, HPLC/UV and ion chromatography with conductivity detection have been used to determine intermediates of degradation. Results The results showed that chloride was a major end product in both TCE and PCE photodegradation. Several intermediates such as formic acid, dichloroacetic acid, dichloroacetaldehyede, chloroform, formaldehyde and glyoxylic acid were formed during both, UV and UV/H2O2 treatment of TCE. However chloroacetaldehyde and chloroacetic acid were only detected during direct UV photolysis of TCE and oxalic acid was only formed during the UV/H2O2 process. For PCE photodegradation, formic acid, di- and trichloroacetic acids were detected in both UV and UV/H2O2 systems, but formaldehyde and glyoxylic acid were only detected during direct UV photolysis. Conclusions For water treatment UV/H2O2 seems to be favorable over direct UV photolysis because of its higher degradation efficiency and lower risk for the formation of harmful intermediates. PMID:24401763

  2. [Degradation of urea and ethyl carbamate in Chinese Rice wine by recombinant acid urease].

    PubMed

    Zhou, Jianli; Kang, Zhen; Liu, Qingtao; Du, Guocheng; Chen, Jian

    2016-01-01

    Ethyl carbamate (EC) as a potential carcinogen commonly exists in traditional fermented foods. It is important eliminate urea that is the precursors of EC in many fermented foods, including Chinese Rice wine. On the basis of achieving high-level overexpression of food-grade ethanol-resistant acid urease, we studied the hydrolysis of urea and EC with the recombinant acid urease. Recombinant acid urease showed degraded urea in both the simulated system with ethanol and Chinese Rice wine (60 mg/L of urea was completely degraded within 25 h), indicating that the recombinant enzyme is suitable for the elimination of urea in Chinese Rice wine. Although recombinant acid urease also has degradation catalytic activity on EC, no obvious degradation of EC was observed. Further investigation results showed that the Km value for urea and EC of the recombinant acid urease was 0.7147 mmol/L and 41.32 mmol/L, respectively. The results provided theoretical foundation for realizing simultaneous degradation of urea and EC.

  3. [Degradation of urea and ethyl carbamate in Chinese Rice wine by recombinant acid urease].

    PubMed

    Zhou, Jianli; Kang, Zhen; Liu, Qingtao; Du, Guocheng; Chen, Jian

    2016-01-01

    Ethyl carbamate (EC) as a potential carcinogen commonly exists in traditional fermented foods. It is important eliminate urea that is the precursors of EC in many fermented foods, including Chinese Rice wine. On the basis of achieving high-level overexpression of food-grade ethanol-resistant acid urease, we studied the hydrolysis of urea and EC with the recombinant acid urease. Recombinant acid urease showed degraded urea in both the simulated system with ethanol and Chinese Rice wine (60 mg/L of urea was completely degraded within 25 h), indicating that the recombinant enzyme is suitable for the elimination of urea in Chinese Rice wine. Although recombinant acid urease also has degradation catalytic activity on EC, no obvious degradation of EC was observed. Further investigation results showed that the Km value for urea and EC of the recombinant acid urease was 0.7147 mmol/L and 41.32 mmol/L, respectively. The results provided theoretical foundation for realizing simultaneous degradation of urea and EC. PMID:27363200

  4. Use of Activated Carbon in Packaging to Attenuate Formaldehyde-Induced and Formic Acid-Induced Degradation and Reduce Gelatin Cross-Linking in Solid Dosage Forms.

    PubMed

    Colgan, Stephen T; Zelesky, Todd C; Chen, Raymond; Likar, Michael D; MacDonald, Bruce C; Hawkins, Joel M; Carroll, Sophia C; Johnson, Gail M; Space, J Sean; Jensen, James F; DeMatteo, Vincent A

    2016-07-01

    Formaldehyde and formic acid are reactive impurities found in commonly used excipients and can be responsible for limiting drug product shelf-life. Described here is the use of activated carbon in drug product packaging to attenuate formaldehyde-induced and formic acid-induced drug degradation in tablets and cross-linking in hard gelatin capsules. Several pharmaceutical products with known or potential vulnerabilities to formaldehyde-induced or formic acid-induced degradation or gelatin cross-linking were subjected to accelerated stability challenges in the presence and absence of activated carbon. The effects of time and storage conditions were determined. For all of the products studied, activated carbon attenuated drug degradation or gelatin cross-linking. This novel use of activated carbon in pharmaceutical packaging may be useful for enhancing the chemical stability of drug products or the dissolution stability of gelatin-containing dosage forms and may allow for the 1) extension of a drug product's shelf-life when the limiting attribute is a degradation product induced by a reactive impurity, 2) marketing of a drug product in hotter and more humid climatic zones than currently supported without the use of activated carbon, and 3) enhanced dissolution stability of products that are vulnerable to gelatin cross-linking.

  5. Selective determination of diclazuril in the presence of its degradation products.

    PubMed

    Rezk, Mamdouh R

    2015-02-01

    A simple stability-indicating high-performance liquid chromatographic method was developed and validated for the determination of diclazuril (DIC) in the presence of its induced degradation products. The drug was subjected to stress stability study including acidic, alkaline, photolytic, thermal and oxidative stress conditions, and the stressed samples were analyzed by the proposed method. The developed method utilized a C18 column (250 × 4.6 mm, i.d., 5 μm) in an isocratic separation mode with mobile phase consisting of acetonitrile and 0.2% phosphoric acid at a flow rate of 1.2 mL/min with UV-detection at 275 nm. The proposed method was validated according to the International Conference on Harmonization guidelines. The method was applied in short term and accelerated stability studies for determination of the DIC in bulk powder and in its pharmaceutical formulation.

  6. Energetics and kinetics of anaerobic aromatic and fatty acid degradation. Final report

    SciTech Connect

    Michael J. McInerney

    1996-06-24

    The factors that affect the rate and extent of a model aromatic compound, benzoate, in methanogenic environments was studied. Benzoate is degraded to a threshold concentration below which no further substrate degradation occurs. The threshold concentration depended on the substrate concentration and the amount of acetate present. The threshold value was not a function of the kinetic ability of the organism or toxicity of the end products. Rather a minimal Gibb's free energy value may exist where thermodynamic constraints preclude further benzoate degradation. In addition, new bacterial species were isolated and described, that degrade benzoate or reduce iron, cobalt and other metals.

  7. Organic Acid Production by Filamentous Fungi

    SciTech Connect

    Magnuson, Jon K.; Lasure, Linda L.

    2004-05-03

    Many of the commercial production processes for organic acids are excellent examples of fungal biotechnology. However, unlike penicillin, the organic acids have had a less visible impact on human well-being. Indeed, organic acid fermentations are often not even identified as fungal bioprocesses, having been overshadowed by the successful deployment of the β-lactam processes. Yet, in terms of productivity, fungal organic acid processes may be the best examples of all. For example, commercial processes using Aspergillus niger in aerated stirred-tank-reactors can convert glucose to citric acid with greater than 80% efficiency and at final concentrations in hundreds of grams per liter. Surprisingly, this phenomenal productivity has been the object of relatively few research programs. Perhaps a greater understanding of this extraordinary capacity of filamentous fungi to produce organic acids in high concentrations will allow greater exploitation of these organisms via application of new knowledge in this era of genomics-based biotechnology. In this chapter, we will explore the biochemistry and modern genetic aspects of the current and potential commercial processes for making organic acids. The organisms involved, with a few exceptions, are filamentous fungi, and this review is limited to that group. Although yeasts including Saccharomyces cerevisiae, species of Rhodotorula, Pichia, and Hansenula are important organisms in fungal biotechnology, they have not been significant for commercial organic acid production, with one exception. The yeast, Yarrowia lipolytica, and related yeast species, may be in use commercially to produce citric acid (Lopez-Garcia, 2002). Furthermore, in the near future engineered yeasts may provide new commercial processes to make lactic acid (Porro, Bianchi, Ranzi, Frontali, Vai, Winkler, & Alberghina, 2002). This chapter is divided into two parts. The first contains a review of the commercial aspects of current and potential large

  8. Modeling the degradation of Portland cement pastes by biogenic organic acids

    SciTech Connect

    De Windt, Laurent; Devillers, Philippe

    2010-08-15

    Reactive transport models can be used to assess the long-term performance of cement-based materials subjected to biodegradation. A bioleaching test (with Aspergillus niger fungi) applied to ordinary Portland cement pastes during 15 months is modeled with HYTEC. Modeling indicates that the biogenic organic acids (acetic, butyric, lactic and oxalic) strongly accelerate hydrate dissolution by acidic hydrolysis whilst their complexation of aluminum has an effect on the secondary gel stability only. The deepest degradation front corresponds to portlandite dissolution and decalcification of calcium silicate hydrates. A complex pattern of sulfate phases dissolution and precipitation takes place in an intermediate zone. The outermost degraded zone consists of alumina and silica gels. The modeling accurateness of calcium leaching, pH evolution and degradation thickness is consistently enhanced whilst considering increase of diffusivity in the degraded zones. Precipitation of calcium oxalate is predicted by modeling but was hindered in the bioleaching reactor.

  9. Fatty acid synthase is preferentially degraded by autophagy upon nitrogen starvation in yeast

    PubMed Central

    Shpilka, Tomer; Welter, Evelyn; Borovsky, Noam; Amar, Nira; Shimron, Frida; Peleg, Yoav; Elazar, Zvulun

    2015-01-01

    Autophagy, an evolutionarily conserved intracellular catabolic process, leads to the degradation of cytosolic proteins and organelles in the vacuole/lysosome. Different forms of selective autophagy have recently been described. Starvation-induced protein degradation, however, is considered to be nonselective. Here we describe a novel interaction between autophagy-related protein 8 (Atg8) and fatty acid synthase (FAS), a pivotal enzymatic complex responsible for the entire synthesis of C16- and C18-fatty acids in yeast. We show that although FAS possesses housekeeping functions, under starvation conditions it is delivered to the vacuole for degradation by autophagy in a Vac8- and Atg24-dependent manner. We also provide evidence that FAS degradation is essential for survival under nitrogen deprivation. Our results imply that during nitrogen starvation specific proteins are preferentially recruited into autophagosomes PMID:25605918

  10. Synthesis and characterization of hydrolytically degradable copolyester biomaterials based on glycolic acid, sebacic acid and ethylene glycol.

    PubMed

    Simitzis, J; Soulis, S; Triantou, D; Zoumpoulakis, L; Zotali, P

    2011-12-01

    Copolyesters of glycolic acid (G) combined with sebacic acid (S) and ethylene glycol were synthesized in different molar ratios (G: 0-100% and S: 100-0%) and their hydrolytic degradation was studied and correlated with their structures. Based on the FTIR spectra of the homopolyesters and copolyesters and the normalized peak intensity of the I(2918), I(2848) and I(1087) for the corresponding wavenumbers, it is concluded that the I(2918) and the I(2848) are in accordance with the mean number degree of polymerization of ethylene sebacate units and the I(1087) is in accordance with the mean number degree of polymerization of glycolate units. Based on the XRD diffractograms, poly(ethylene sebacate) and poly(glycolic acid) belong to the monoclinic and the orthorhombic crystal system, respectively and both have higher crystallinity than the copolyesters. The experimental data of the hydrolytic degradation were fitted with exponential rise to maximum type functions using two-parameter model and four-parameter model. Three regions can been distinguished for the hydrolytic degradation by decreasing the molar feed ratio of sebacic acid, which are correlated with the changes of crystallinity. Two copolyesters are proposed: first the copolyester with high amount of glycolate units (S10G90) having higher hydrolytic degradation than G100 and second the copolyester with equal amount of glycolate and ethylene sebacate units (S50G50), having lower hydrolytic degradation than G100. These hydrolytically degradable copolyesters are soluble in common organic solvents, opposite to poly(glycolic acid) and could have perspectives for biomedical applications.

  11. The earthworm Aporrectodea caliginosa stimulates abundance and activity of phenoxyalkanoic acid herbicide degraders

    PubMed Central

    Liu, Ya-Jun; Zaprasis, Adrienne; Liu, Shuang-Jiang; Drake, Harold L; Horn, Marcus A

    2011-01-01

    2-Methyl-4-chlorophenoxyacetic acid (MCPA) is a widely used phenoxyalkanoic acid (PAA) herbicide. Earthworms represent the dominant macrofauna and enhance microbial activities in many soils. Thus, the effect of the model earthworm Aporrectodea caliginosa (Oligochaeta, Lumbricidae) on microbial MCPA degradation was assessed in soil columns with agricultural soil. MCPA degradation was quicker in soil with earthworms than without earthworms. Quantitative PCR was inhibition-corrected per nucleic acid extract and indicated that copy numbers of tfdA-like and cadA genes (both encoding oxygenases initiating aerobic PAA degradation) in soil with earthworms were up to three and four times higher than without earthworms, respectively. tfdA-like and 16S rRNA gene transcript copy numbers in soil with earthworms were two and six times higher than without earthworms, respectively. Most probable numbers (MPNs) of MCPA degraders approximated 4 × 105 gdw−1 in soil before incubation and in soil treated without earthworms, whereas MPNs of earthworm-treated soils were approximately 150 × higher. The aerobic capacity of soil to degrade MCPA was higher in earthworm-treated soils than in earthworm-untreated soils. Burrow walls and 0–5 cm depth bulk soil displayed higher capacities to degrade MCPA than did soil from 5–10 cm depth bulk soil, expression of tfdA-like genes in burrow walls was five times higher than in bulk soil and MCPA degraders were abundant in burrow walls (MPNs of 5 × 107 gdw−1). The collective data indicate that earthworms stimulate abundance and activity of MCPA degraders endogenous to soil by their burrowing activities and might thus be advantageous for enhancing PAA degradation in soil. PMID:20740027

  12. Crystal Structure and Substrate Recognition of Cellobionic Acid Phosphorylase, Which Plays a Key Role in Oxidative Cellulose Degradation by Microbes*

    PubMed Central

    Nam, Young-Woo; Nihira, Takanori; Arakawa, Takatoshi; Saito, Yuka; Kitaoka, Motomitsu; Nakai, Hiroyuki; Fushinobu, Shinya

    2015-01-01

    The microbial oxidative cellulose degradation system is attracting significant research attention after the recent discovery of lytic polysaccharide mono-oxygenases. A primary product of the oxidative and hydrolytic cellulose degradation system is cellobionic acid (CbA), the aldonic acid form of cellobiose. We previously demonstrated that the intracellular enzyme belonging to glycoside hydrolase family 94 from cellulolytic fungus and bacterium is cellobionic acid phosphorylase (CBAP), which catalyzes reversible phosphorolysis of CbA into glucose 1-phosphate and gluconic acid (GlcA). In this report, we describe the biochemical characterization and the three-dimensional structure of CBAP from the marine cellulolytic bacterium Saccharophagus degradans. Structures of ligand-free and complex forms with CbA, GlcA, and a synthetic disaccharide product from glucuronic acid were determined at resolutions of up to 1.6 Å. The active site is located near the dimer interface. At subsite +1, the carboxylate group of GlcA and CbA is recognized by Arg-609 and Lys-613. Additionally, one residue from the neighboring protomer (Gln-190) is involved in the carboxylate recognition of GlcA. A mutational analysis indicated that these residues are critical for the binding and catalysis of the aldonic and uronic acid acceptors GlcA and glucuronic acid. Structural and sequence comparisons with other glycoside hydrolase family 94 phosphorylases revealed that CBAPs have a unique subsite +1 with a distinct amino acid residue conservation pattern at this site. This study provides molecular insight into the energetically efficient metabolic pathway of oxidized sugars that links the oxidative cellulolytic pathway to the glycolytic and pentose phosphate pathways in cellulolytic microbes. PMID:26041776

  13. Preparation and characterization of two new forced degradation products of letrozole and development of a stability-indicating RP-LC method for its determination.

    PubMed

    Elkady, Ehab Farouk; Fouad, Marwa Ahmed

    2015-11-01

    Two new hydrolytic products of letrozole were identified and proved to be true degradation products obtained by alkaline and acidic degradation of the drug. The acid and amide forms of the nitrile groups of letrozole were prepared and identified by IR and mass spectroscopic techniques. Subsequently, a simple, precise and selective stability-indicating RPLC method was developed and validated for the determination of letrozole in the presence of its degradation products. Letrozole was subjected to alkali and acid hydrolysis, oxidation, thermal degradation and photo-degradation. The degradation products were well isolated from letrozole. The chromatographic method was achieved using gradient elution of the drug and its degradation products on a reversed phase Zorbax Eclipse C18 column (100mm x 4.6mm, 3.5 μm) using a mobile phase consisting of 0.01M KH₂PO₄and methanol at a flow rate of 1 mL min⁻¹. Quantitation was achieved with UV detection at 230 nm. Linearity, accuracy and precision were found to be acceptable over the concentration range of 0.01-80 μgmL⁻¹. The proposed method was successfully applied to the determination of letrozole in bulk, plasma and in its pharmaceutical preparation.

  14. Energetics and kinetics of anaerobic aromatic and fatty acid degradation. Progress report, March 1992--June 1995

    SciTech Connect

    McInerney M.J.

    1995-06-23

    Factors affecting the rate and extent of benzoate degradation by anaerobic syntrophic consortia were studied. Cocultures of a syntrophic benzoate degrader, strain SB, with a hydrogen/formate-using sulfate reducer degraded benzoate to a threshold that depended on the amount of substrate and acetate present. The benzoate threshold was not a function of the inhibition of benzoate degradation capacity by acetate or the toxicity of the undissociated form of acetate. Rather, a critical or minimal Gibb`s free energy value may exist where thermodynamic constraints preclude further benzoate degradation. A sensitive assay to detect low formate concentrations was developed to measure the formate levels when the benzoate threshold was reached. We showed that increased acetate concentrations, even when hydrogen and formate levels are low, affects the extent of benzoate degradation, implicating the importance of interspecies acetate transfer. In addition to benzoate, various saturated and unsaturated fatty acids, 2-methylbutyrate, and methyl esters of fatty acids supported growth in coculture with a hydrogen-using partner. SB is the only syntrophic bacterium known to use both benzoate and fatty acids. Phylogenetic analysis showed that SB clustered with sulfate reducers in the delta subclass of the Proteobacteria. SB grew well in coculture with Desulfoarculus baarsii, a sulfate reducer that uses formate but not hydrogen. This unequivocally shows that SB can grow by interspecies formate transfer.

  15. Lactic Acid and Biosurfactants Production from Residual Cellulose Films.

    PubMed

    Portilla Rivera, Oscar Manuel; Arzate Martínez, Guillermo; Jarquín Enríquez, Lorenzo; Vázquez Landaverde, Pedro Alberto; Domínguez González, José Manuel

    2015-11-01

    The increasing amounts of residual cellulose films generated as wastes all over the world represent a big scale problem for the meat industry regarding to environmental and economic issues. The use of residual cellulose films as a feedstock of glucose-containing solutions by acid hydrolysis and further fermentation into lactic acid and biosurfactants was evaluated as a method to diminish and revalorize these wastes. Under a treatment consisting in sulfuric acid 6% (v/v); reaction time 2 h; solid liquid ratio 9 g of film/100 mL of acid solution, and temperature 130 °C, 35 g/L of glucose and 49% of solubilized film was obtained. From five lactic acid strains, Lactobacillus plantarum was the most suitable for metabolizing the glucose generated. The process was scaled up under optimized conditions in a 2-L bioreactor, producing 3.4 g/L of biomass, 18 g/L of lactic acid, and 15 units of surface tension reduction of a buffer phosphate solution. Around 50% of the cellulose was degraded by the treatment applied, and the liqueurs generated were useful for an efficient production of lactic acid and biosurfactants using L. plantarum. Lactobacillus bacteria can efficiently utilize glucose from cellulose films hydrolysis without the need of clarification of the liqueurs.

  16. Degradation of hydroxycinnamic acid mixtures in aqueous sucrose solutions by the Fenton process.

    PubMed

    Nguyen, Danny M T; Zhang, Zhanying; Doherty, William O S

    2015-02-11

    The degradation efficiencies and behaviors of caffeic acid (CaA), p-coumaric acid (pCoA), and ferulic acid (FeA) in aqueous sucrose solutions containing the mixture of these hydroxycinnamic acids (HCAs) were studied by the Fenton oxidation process. Central composite design and multiresponse surface methodology were used to evaluate and optimize the interactive effects of process parameters. Four quadratic polynomial models were developed for the degradation of each individual acid in the mixture and the total HCAs degraded. Sucrose was the most influential parameter that significantly affected the total amount of HCA degraded. Under the conditions studied there was a <0.01% loss of sucrose in all reactions. The optimal values of the process parameters for a 200 mg/L HCA mixture in water (pH 4.73, 25.15 °C) and sucrose solution (13 mass %, pH 5.39, 35.98 °C) were 77% and 57%, respectively. Regression analysis showed goodness of fit between the experimental results and the predicted values. The degradation behavior of CaA differed from those of pCoA and FeA, where further CaA degradation is observed at increasing sucrose and decreasing solution pH. The differences (established using UV/vis and ATR-FTIR spectroscopy) were because, unlike the other acids, CaA formed a complex with Fe(III) or with Fe(III) hydrogen-bonded to sucrose and coprecipitated with lepidocrocite, an iron oxyhydroxide. PMID:25585639

  17. Degradation of hydroxycinnamic acid mixtures in aqueous sucrose solutions by the Fenton process.

    PubMed

    Nguyen, Danny M T; Zhang, Zhanying; Doherty, William O S

    2015-02-11

    The degradation efficiencies and behaviors of caffeic acid (CaA), p-coumaric acid (pCoA), and ferulic acid (FeA) in aqueous sucrose solutions containing the mixture of these hydroxycinnamic acids (HCAs) were studied by the Fenton oxidation process. Central composite design and multiresponse surface methodology were used to evaluate and optimize the interactive effects of process parameters. Four quadratic polynomial models were developed for the degradation of each individual acid in the mixture and the total HCAs degraded. Sucrose was the most influential parameter that significantly affected the total amount of HCA degraded. Under the conditions studied there was a <0.01% loss of sucrose in all reactions. The optimal values of the process parameters for a 200 mg/L HCA mixture in water (pH 4.73, 25.15 °C) and sucrose solution (13 mass %, pH 5.39, 35.98 °C) were 77% and 57%, respectively. Regression analysis showed goodness of fit between the experimental results and the predicted values. The degradation behavior of CaA differed from those of pCoA and FeA, where further CaA degradation is observed at increasing sucrose and decreasing solution pH. The differences (established using UV/vis and ATR-FTIR spectroscopy) were because, unlike the other acids, CaA formed a complex with Fe(III) or with Fe(III) hydrogen-bonded to sucrose and coprecipitated with lepidocrocite, an iron oxyhydroxide.

  18. Production of Succinic Acid for Lignocellulosic Hydrolysates

    SciTech Connect

    Davison, B.H.; Nghiem, J.

    2002-06-01

    The purpose of this Cooperative Research and Development Agreement (CRADA) is to add and test new metabolic activities to existing microbial catalysts for the production of succinic acid from renewables. In particular, they seek to add to the existing organism the ability to utilize xylose efficiently and simultaneously with glucose in mixtures of sugars or to add succinic acid production to another strain and to test the value of this new capability for production of succinic acid from industrial lignocellulosic hydrolyasates. The Contractors and Participant are hereinafter jointly referred to as the 'Parties'. Research to date in succinic acid fermentation, separation and genetic engineering has resulted in a potentially economical process based on the use of an Escherichia coli strain AFP111 with suitable characteristics for the production of succinic acid from glucose. Economic analysis has shown that higher value commodity chemicals can be economically produced from succinic acid based on repliminary laboratory findings and predicted catalytic parameters. The initial target markets include succinic acid itself, succinate salts, esters and other derivatives for use as deicers, solvents and acidulants. The other commodity products from the succinic acid platform include 1,4-butanediol, {gamma}-butyrolactone, 2-pyrrolidinone and N-methyl pyrrolidinone. Current economic analyses indicate that this platform is competitive with existing petrochemical routes, especially for the succinic acid and derivatives. The report presents the planned CRADA objectives followed by the results. The results section has a combined biocatalysis and fermentation section and a commercialization section. This is a nonproprietary report; additional proprietary information may be made available subject to acceptance of the appropriate proprietary information agreements.

  19. 1H NMR spectra of humic and fulvic acids and their peracetic oxidation products

    NASA Astrophysics Data System (ADS)

    Ruggiero, P.; Interesse, F. S.; Cassidei, L.; Sciacovelli, O.

    1980-04-01

    1H NMR spectra of humic (HA) and fulvic (FA) acids and their oxidative degradation products are reported. The HA shows the presence of -( CH2) n - CH3 ( n > 6) chemical fragments belonging to n-alkanes and/or n-fatty acids physically adsorbed onto the macromolecule structure. These fragments are absent in the FA fraction. Both humic fractions reveal the presence of similar amounts of aromatic protons which partly undergo exchange phenomena. The importance of this experimental observation is discussed. Oxidative degradation seems to cause partial cleavage of aromatic rings, more pronounced in the FA than in the HA. The degraded FA shows a higher total acidity and a higher phenolic OH content than the degraded HA. Both degraded fractions display some sharp singlet signals at 1.9 and 3.9 ppm arising from protons belonging to repetitive chemical fragments probably formed during the oxidation reaction. Tentative assignments of these signals are given. A general analysis of the HA and FA degraded spectra seems to indicate that the chemical fragments which undergo peracetic oxidation are substantially similar. The extent of oxidation of the two humic fractions is different. The HA degradation products reveal the presence of oligomeric structures, whereas the degraded FA appears less resistant to the oxidizing agent.

  20. Degradation of the antibiotic oxolinic acid by photocatalysis with TiO2 in suspension.

    PubMed

    Giraldo, Ana L; Peñuela, Gustavo A; Torres-Palma, Ricardo A; Pino, Nancy J; Palominos, Rodrigo A; Mansilla, Héctor D

    2010-10-01

    In the work presented here, a photocatalytic system using titanium Degussa P-25 in suspension was used to evaluate the degradation of 20mg L(-1) of antibiotic oxolinic acid (OA). The effects of catalyst load (0.2-1.5 g L(-1)) and pH (7.5-11) were evaluated and optimized using the surface response methodology and the Pareto diagram. In the range of variables studied, low pH values and 1.0 g L(-1) of TiO(2) favoured the efficiency of the process. Under optimal conditions the evolution of the substrate, chemical oxygen demand, dissolved organic carbon, toxicity and antimicrobial activity on Escherichia coli cultures were evaluated. The results indicate that, under optimal conditions, after 30 min, the TiO(2) photocatalytic system is able to eliminate both the substrate and the antimicrobial activity, and to reduce the toxicity of the solution by 60%. However, at the same time, ∼53% of both initial DOC and COD remain in solution. Thus, the photocatalytical system is able to transform the target compound into more oxidized by-products without antimicrobial activity and with a low toxicity. The study of OA by-products using liquid chromatography coupled with mass spectrometry, as well as the evaluation of OA degradation in acetonitrile media as solvent or in the presence of isopropanol and iodide suggest that the reaction is initiated by the photo-Kolbe reaction. Adsorption isotherm experiments in the dark indicated that under pH 7.5, adsorption corresponded to the Langmuir adsorption model, indicating the dependence of the reaction on an initial adsorption step. PMID:20633918

  1. Degradation of oleic acid in anaerobic filters: the effect of inoculum acclimatization and biomass recirculation.

    PubMed

    Pereira, A; Mota, M; Alves, M

    2001-01-01

    The degradation of oleic acid in anaerobic filters was studied and the effect of an acclimated inoculum and biomass recirculation was evaluated. Three anaerobic filters (R1, R2, and R3) were operated in parallel. The anaerobic filters R1 and R2 were inoculated with nonacclimated biomass, whereas the anaerobic filter R3 was inoculated with acclimated biomass. In the anaerobic filters R2 and R3, biomass settling and recirculation were applied. The use of an acclimated inoculum and biomass recirculation (R3) was beneficial in terms of removal efficiency, which was 4 to 8% higher than in the anaerobic filters R1 and R2 when oleate was the sole carbon source fed to the reactors at an applied organic load of 12.5 kg of chemical oxygen demand (COD)/m3 x d, even with an oleate to calcium and magnesium ion molar concentration ratio of 6.8. Biomass recirculation significantly reduced the biomass washout and the toxic effect on the acetogenic and methanogenic populations. The use of an acclimated inoculum was beneficial in terms of methane yield, which was 50% greater than that observed for the reactors inoculated with nonacclimated inoculum for the highest applied organic loading rate (12.5 kg COD/m3 x d). At the end of the operation, the biomass was encapsulated by a whitish matter, which was well detected by microscopic examination. When this sludge was incubated in batch vials at 37 degrees C where no substrate was added, methane production from the adsorbed organic matter was evidenced, attaining a maximum value (at standard temperature and pressure) of 39.7 mL/g volatile solids x d for the biomass taken from R1. With stirring (150 r/min), the methane production rate was 13.8 times higher than under static conditions. When oleate was added to this sludge, methane production was delayed, suggesting that adsorbed matter can be an intermediate of oleate degradation such as stearic, palmitic, myristic, or other saturated acids.

  2. Enzymes involved in a novel anaerobic cyclohexane carboxylic acid degradation pathway.

    PubMed

    Kung, Johannes W; Meier, Anne-Katrin; Mergelsberg, Mario; Boll, Matthias

    2014-10-01

    The anaerobic degradation of cyclohexane carboxylic acid (CHC) has so far been studied only in Rhodopseudomonas palustris, in which CHC is activated to cyclohexanoyl coenzyme A (cyclohexanoyl-CoA [CHCoA]) and then dehydrogenated to cyclohex-1-ene-1-carboxyl-CoA (CHeneCoA). This intermediate is further degraded by reactions of the R. palustris-specific benzoyl-CoA degradation pathway of aromatic compounds. However, CHeneCoA is not an intermediate in the degradation of aromatic compounds in all other known anaerobic bacteria; consequently, degradation of CHC was mostly unknown in anaerobic bacteria. We identified a previously unknown CHC degradation pathway in the Fe(III)-reducing Geobacter metallireducens by determining the following CHC-induced in vitro activities: (i) the activation of CHC to CHCoA by a succinyl-CoA:CHC CoA transferase, (ii) the 1,2-dehydrogenation of CHCoA to CHeneCoA by CHCoA dehydrogenase, and (iii) the unusual 1,4-dehydrogenation of CHeneCoA to cyclohex-1,5-diene-1-carboxyl-CoA. This last represents a previously unknown joint intermediate of the CHC and aromatic compound degradation pathway in bacteria other than R. palustris. The enzymes catalyzing the three reactions were purified and characterized as specific enzymes after heterologous expression of the encoding genes. Quantitative reverse transcription-PCR revealed that expression of these genes was highly induced during growth with CHC but not with benzoate. The newly identified CHC degradation pathway is suggested to be present in nearly all CHC-degrading anaerobic bacteria, including denitrifying, Fe(III)-reducing, sulfate-reducing, and fermenting bacteria. Remarkably, all three CHC degradation pathways always link CHC catabolism to the catabolic pathways of aromatic compounds. We propose that the capacity to use CHC as a carbon source evolved from already-existing aromatic compound degradation pathways. PMID:25112478

  3. LC-MS/TOF, LC-MSn, on-line H/D exchange and LC-NMR studies on rosuvastatin degradation and in silico determination of toxicity of its degradation products: a comprehensive approach during drug development.

    PubMed

    Shah, Ravi P; Sahu, Archana; Singh, Saranjit

    2013-04-01

    The present study dealt with the forced degradation behaviour of rosuvastatin under ICH prescribed stress conditions. The drug was found to be labile under acid hydrolytic and photolytic conditions, while it was stable to base/neutral hydrolytic, oxidative and thermal stress. In total, 11 degradation products were formed, which were separated on a C-18 column using a stability-indicating method. LC-MS analyses indicated that five degradation products had the same molecular mass as that of the drug, while the remaining six had 18 Da less than the drug. Structure elucidation of all the degradation products was executed using sophisticated and modern structural characterization tools, viz. LC-MS/TOF, LC-MS(n), on-line H/D exchange and LC-NMR. The degradation pathway and mechanisms of degradation of the drug were delineated. Additionally, in silico toxicity was predicted for all the degradation products using TOPKAT and DEREK software and compared with the drug. This study demonstrates a comprehensive approach of degradation studies during the drug development phase.

  4. Analysis of genes encoding the 2,4-dichlorophenoxyacetic acid-degrading enzyme from Sphingomonas agrestis 58-1.

    PubMed

    Shimojo, Mitsuhiro; Kawakami, Mitsuyasu; Amada, Kei

    2009-07-01

    A 2,4-dichlorophenoxy acetic acid (2,4-D)-degrading bacterium, strain 58-1, was newly isolated from soil samples collected in the Fukuoka Prefecture, Japan, and grown on an enrichment culture medium containing 2,4-D as the sole carbon source. Phylogenic analysis identified strain 58-1 as Sphingomonas agrestis. In 2,4-D degraders, classes I, II, and III inherit the tfdA, cadA, and tfdAalpha genes, respectively, and the results from degenerate-PCR indicated that this strain belongs to the class II degraders. A clone that includes the cadA gene homolog of S. agrestis 58-1 was screened from a library by using the PCR amplified fragment as a DNA probe. The cloned fragment was sequenced and found to consist of 5043 nucleotides and include 3 open reading frames (orfs). The orf1, orf2, and orf3 genes encode polypeptides consisting of 412, 448, and 177 amino acids, respectively. The Orf2 product shares a high degree of sequence similarity (92%) with the large subunit of 2,4-D oxygenase from the Bradyrhizobium sp. strain HW13, which belongs to the class III 2,4-D degraders, while the orf3 product shared 63% sequence similarity with the small subunit of 2,4-D oxygenase from the strain HW13. The results of the functional expression analysis using various deletion mutants in Escherichia coli revealed that the expression of both orf2 and orf3 genes, but not orf1, is essential for the conversion of 2,4-D to 2,4-DCP. From these results, we conclude the first isolation of 2,4-D oxygenase genes from a class II 2,4-D degrader.

  5. Adsorption and degradation of phenoxyalkanoic acid herbicides in soils: A review.

    PubMed

    Paszko, Tadeusz; Muszyński, Paweł; Materska, Małgorzata; Bojanowska, Monika; Kostecka, Małgorzata; Jackowska, Izabella

    2016-02-01

    The primary aim of the present review on phenoxyalkanoic acid herbicides-2-(2,4-dichlorophenoxy) acetic acid (2,4-D), 2-(4-chloro-2-methylphenoxy) acetic acid (MCPA), (2R)-2-(2,4-dichlorophenoxy) propanoic acid (dichlorprop-P), (2R)-2-(4-chloro-2-methylphenoxy) propanoic acid (mecoprop-P), 4-(2,4-dichlorophenoxy) butanoic acid (2,4-DB), and 4-(4-chloro-2-methylphenoxy) butanoic acid (MCPB)-was to compare the extent of their adsorption in soils and degradation rates to assess their potential for groundwater contamination. The authors found that adsorption decreased in the sequence of 2,4-DB > 2,4-D > MCPA > dichlorprop-P > mecoprop-P. Herbicides are predominantly adsorbed as anions-on organic matter and through a water-bridging mechanism with adsorbed Fe cations-and their neutral forms are adsorbed mainly on organic matter. Adsorption of anions of 2,4-D, MCPA, dichlorprop-P, and mecoprop-P is inversely correlated with their lipophilicity values, and modeling of adsorption of the compounds based on this relationship is possible. The predominant dissipation mechanism of herbicides in soils is bacterial degradation. The contribution of other mechanisms, such as degradation by fungi, photodegradation, or volatilization from soils, is much smaller. The rate of bacterial degradation decreased in the following order: 2,4-D > MCPA > mecoprop-P > dichlorprop-P. It was found that 2,4-D and MCPA have the lowest potential for leaching into groundwater and that mecoprop-P and dichlorprop-P have slightly higher potential. Because of limited data on adsorption and degradation of 2,4-DB and MCPB, estimation of their leaching potential was not possible.

  6. Photocatalytic degradation of L-acid by TiO2 supported on the activated carbon.

    PubMed

    Wang, Yu-Ping; Wang, Lian-Jun; Peng, Pan-Ying

    2006-01-01

    TiO2 sol was prepared by sol-gel technique with tetrabutyl titanate as precursor. Supported TiO2 catalysts on activated carbon were prepared by soak and sintering method. The aggregation of nano-TiO2 particles can be effectively suppressed by added polyethylene glycol (PEG) as a surface modifier. The average particle diameter of TiO2, specific surface area and absorbability of catalyst can be modified. Based on characteristics of the TiO2 photocatalyst with XRD, specific surface area, adsorption valves of methylene blue and the amount of TiO2 supported on the activated carbon, the photocatalytic degradation of L-acid was studied. The effect of the factors, such as pH of the solution, the initial concentration of L-acid on the photocatalytic degradation of L-acid, were studied also. It was found that when the pH of the solution is 1.95, the amount of photocatalyst is 0.5 g, the concentration of the L-acid solution is 1.34 x 10(-3) mol/L and the illumination time is 7 h, the photocatalytic degradation efficiency of L-acid can reach 89.88%. The catalyst was reused 6 times and its degradation efficiency hardly changed.

  7. Wheat straw degradation and production of alternative substrates for nitrogenase of Rhodobacter sphaeroides.

    PubMed

    Dziga, Dariusz; Jagiełło-Flasińska, Dominika

    2015-01-01

    Cellulose is a major component of plant biomass and could be applied in the production of biofuels, especially bioethanol. An alternative approach is production of a clean fuel - hydrogen from cellulosic biomass. In this paper an innovatory model of cellulosic waste degradation has been proposed to verify the possibility of utilization of cellulose derivatives by purple non-sulfur bacteria. The concept is based on a two-step process of wheat straw conversion by bacteria in order to obtain an organic acid mixture. In the next stage such products are consumed by Rhodobacter sphaeroides, the known producer of hydrogen. It has been documented that Cellulomonas uda expresses cellulolytic activity in the presence of wheat straw as an only source of carbon. R. sphaeroides applied in this research can effectively consume organic acids released from straw by C. uda and Lactobacillus rhamnosus and is able to grow in the presence of these substrates. Additionally, an increased nitrogenase activity of R. sphaeroides has been indicated when bacteria were cultivated in the presence of cellulose derivatives which suggests that hydrogen production occurs.

  8. Wheat straw degradation and production of alternative substrates for nitrogenase of Rhodobacter sphaeroides.

    PubMed

    Dziga, Dariusz; Jagiełło-Flasińska, Dominika

    2015-01-01

    Cellulose is a major component of plant biomass and could be applied in the production of biofuels, especially bioethanol. An alternative approach is production of a clean fuel - hydrogen from cellulosic biomass. In this paper an innovatory model of cellulosic waste degradation has been proposed to verify the possibility of utilization of cellulose derivatives by purple non-sulfur bacteria. The concept is based on a two-step process of wheat straw conversion by bacteria in order to obtain an organic acid mixture. In the next stage such products are consumed by Rhodobacter sphaeroides, the known producer of hydrogen. It has been documented that Cellulomonas uda expresses cellulolytic activity in the presence of wheat straw as an only source of carbon. R. sphaeroides applied in this research can effectively consume organic acids released from straw by C. uda and Lactobacillus rhamnosus and is able to grow in the presence of these substrates. Additionally, an increased nitrogenase activity of R. sphaeroides has been indicated when bacteria were cultivated in the presence of cellulose derivatives which suggests that hydrogen production occurs. PMID:26192769

  9. Reflectance model for quantifying chlorophyll a in the presence of productivity degradation products

    NASA Technical Reports Server (NTRS)

    Carder, K. L.; Hawes, S. K.; Steward, R. G.; Baker, K. A.; Smith, R. C.; Mitchell, B. G.

    1991-01-01

    A reflectance model developed to estimate chlorophyll a concentrations in the presence of marine colored dissolved organic matter, pheopigments, detritus, and bacteria is presented. Nomograms and lookup tables are generated to describe the effects of different mixtures of chlorophyll a and these degradation products on the R(412):R(443) and R(443):R(565) remote-sensing reflectance or irradiance reflectance ratios. These are used to simulate the accuracy of potential ocean color satellite algorithms, assuming that atmospheric effects have been removed. For the California Current upwelling and offshore regions, with chlorophyll a not greater than 1.3 mg/cu m, the average error for chlorophyll a retrievals derived from irradiance reflectance data for degradation product-rich areas was reduced from +/-61 percent to +/-23 percent by application of an algorithm using two reflectance ratios rather than the commonly used algorithm applying a single reflectance ratio.

  10. The Inhibitory Effect of Natural Products on Protein Fibrillation May Be Caused by Degradation Products – A Study Using Aloin and Insulin

    PubMed Central

    Lobbens, Eva S.; Foderà, Vito; Nyberg, Nils T.; Andersen, Kirsten; Jäger, Anna K.; Jorgensen, Lene; van de Weert, Marco

    2016-01-01

    Protein fibrillation is the pathological hallmark of several neurodegenerative diseases and also complicates the manufacturing and use of protein drugs. As a case study, the inhibitory activity of the natural compound aloin against insulin fibrillation was investigated. Based on Thioflavin T assays, high-performance liquid chromatography and transmission electron microscopy it was found that a degradation product of aloin, formed over weeks of storage, was able to significantly inhibit insulin fibrillation. The activity of the stored aloin was significantly reduced in the presence of small amounts of sodium azide or ascorbic acid, suggesting the active compound to be an oxidation product. A high-performance liquid chromatography method and a liquid chromatography-mass spectrometry method were developed to investigate the degradation products in the aged aloin solution. We found that the major compounds in the solution were aloin A and aloin B. In addition, 10-hydroxy aloin and elgonica dimers were detected in smaller amounts. The identified compounds were isolated and tested for activity by means of Thioflavin T assays, but no activity was observed. Thus, the actual fibrillation inhibitor is an as yet unidentified and potentially metastable degradation product of aloin. These results suggest that degradation products, and in particular oxidation products, are to be considered thoroughly when natural products are investigated for activity against protein fibrillation. PMID:26882071

  11. Dynamics of propionic acid degradation in a two-phase anaerobic system.

    PubMed

    Xiao, Keke; Zhou, Yan; Guo, Chenghong; Maspolim, Yogananda; Ng, Wun-Jern

    2015-12-01

    This paper reports on propionic acid (HPr) degradation in a laboratory scale two-phase anaerobic system, where HPr was accumulated in the acidogenic reactor and degraded in the methanogenic reactor. Batch tests using biomass from the two-phase anaerobic system showed HPr degradation was rarely detectable in the acidogenic reactor when HPr concentration ranged from 639 to 4531mgHPrL(-1) and at pH 4.50 to 6.50. Biomass from the methanogenic reactor could, however, successfully degrade HPr at its initial concentration of up to 4585mgHPrL(-1) at pH 6.40-7.30. ATP results showed that differences in the degradation ability of HPr by the acidogenic and methanogenic biomass may be related with their respective different biomass activities. Results from pyrosequencing showed that the predominant propionic acid oxidizing bacteria (POB) in the methanogenic reactor were Smithella (2.68%) and Syntrophobacter (0.35%); while poor degradation of HPr in the acidogenic reactor may be associated with the low abundance of POB (0.02% Desulfacinum and 0.08% Desulfobulbus). This might have been induced by the long-term unfavorable environment for POB growth in the acidogenic reactor.

  12. The role of degradant profiling in active pharmaceutical ingredients and drug products.

    PubMed

    Alsante, Karen M; Ando, Akemi; Brown, Roland; Ensing, Janice; Hatajik, Todd D; Kong, Wei; Tsuda, Yoshiko

    2007-01-10

    Forced degradation studies are used to facilitate the development of analytical methodology, to gain a better understanding of active pharmaceutical ingredient (API) and drug product (DP) stability, and to provide information about degradation pathways and degradation products. In order to fulfill development and regulatory needs, this publication provides a roadmap for when and how to perform studies, helpful tools in designing rugged scientific studies, and guidance on how to record and communicate results. PMID:17187892

  13. Detection of explosives and their degradation products in soil environments.

    PubMed

    Halasz, A; Groom, C; Zhou, E; Paquet, L; Beaulieu, C; Deschamps, S; Corriveau, A; Thiboutot, S; Ampleman, G; Dubois, C; Hawari, Jalal

    2002-07-19

    Polynitro organic explosives [hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) and 2,4,6-trinitrotoluene (TNT)] are typical labile environmental pollutants that can biotransform with soil indigenous microorganisms, photodegrade by sunlight and migrate through subsurface soil to cause groundwater contamination. To be able to determine the type and concentration of explosives and their (bio)transformation products in different soil environments, a comprehensive analytical methodology of sample preparation, separation and detection is thus required. The present paper describes the use of supercritical carbon dioxide (SC-CO2), acetonitrile (MeCN) (US Environmental Protection Agency Method 8330) and solid-phase microextraction (SPME) for the extraction of explosives and their degradation products from various water, soil and plant tissue samples for subsequent analysis by either HPLC-UV, capillary electrophoresis (CE-UV) or GC-MS. Contaminated surface and subsurface soil and groundwater were collected from either a TNT manufacturing facility or an anti-tank firing range. Plant tissue samples were taken fromplants grown in anti-tank firing range soil in a greenhouse experiment. All tested soil and groundwater samples from the former TNT manufacturing plant were found to contain TNT and some of its amino reduced and partially denitrated products. Their concentrations as determined by SPME-GC-MS and LC-UV depended on the location of sampling at the site. In the case of plant tissues, SC-CO2 extraction followed by CE-UV analysis showed only the presence of HMX. The concentrations of HMX (<200 mg/kg) as determined by supercritical fluid extraction (SC-CO2)-CE-UV were comparable to those obtained by MeCN extraction, although the latter technique was found to be more efficient at higher concentrations (>300 mg/kg). Modifiers such as MeCN and water enhanced the SC-CO2 extractability of HMX from plant tissues.

  14. Stability-Indicating RP-HPLC Method for Simultaneous Estimation of Enrofloxacin and Its Degradation Products in Tablet Dosage Forms.

    PubMed

    Chakravarthy, V Ashok; Sailaja, B B V; Kumar, Avvaru Praveen

    2015-01-01

    The present work was the development of a simple, efficient, and reproducible stability-indicating reverse-phase high performance liquid chromatographic (RP-HPLC) method for simultaneous determination enrofloxacin (EFX) and its degradation products including ethylenediamine impurity, desfluoro impurity, ciprofloxacin impurity, chloro impurity, fluoroquinolonic acid impurity, and decarboxylated impurity in tablet dosage forms. The separation of EFX and its degradation products in tablets was carried out on Kromasil C-18 (250 × 4.6 mm, 5 μm) column using 0.1% (v/v) TEA in 10 mM KH2PO4 (pH 2.5) buffer and methanol by linear gradient program. Flow rate was 1.0 mL min(-1) with a column temperature of 35°C and detection wavelength was carried out at 278 nm and 254 nm. The forced degradation studies were performed on EFX tablets under acidic, basic, oxidation, thermal, humidity, and photolytic conditions. The degraded products were well resolved from the main active drug and also from known impurities within 65 minutes. The method was validated in terms of specificity, linearity, LOD, LOQ, accuracy, precision, and robustness as per ICH guidelines. The results obtained from the validation experiments prove that the developed method is a stability-indicating method and suitable for routine analysis. PMID:25705547

  15. Isolation and characterization of Bradyrhizobium sp. 224 capable of degrading sulfanilic acid.

    PubMed

    Hayase, Nobuki; Fujikawa, Yui; Nakagawa, Katsuhiko; Ushio, Kazutoshi

    2016-08-01

    A bacterial strain (strain 224), which has the ability to utilize sulfanilic acid as a sole source of carbon, was isolated from soil. 16S rRNA gene sequence obtained from strain 224 exhibited 100% identical to that of species in the genus Bradyrhizobium. Strain 224 degraded 4.7 mM of sulfanilic acid and released almost the same molar concentration of sulfate ion.

  16. Degradation kinetic modelling of ascorbic acid and colour intensity in pasteurised blood orange juice during storage.

    PubMed

    Remini, Hocine; Mertz, Christian; Belbahi, Amine; Achir, Nawel; Dornier, Manuel; Madani, Khodir

    2015-04-15

    The stability of ascorbic acid and colour intensity in pasteurised blood orange juice (Citrus sinensis [L.] Osbeck) during one month of storage was investigated at 4-37 °C. The effects of ascorbic acid fortification (at 100, 200 mg L(-1)) and deaeration, temperature/time storage on the kinetic behaviour were determined. Ascorbic acid was monitored by HPLC-DAD and colour intensity by spectrophotometric measurements. Degradation kinetics were best fitted by first-order reaction models for both ascorbic acid and colour intensity. Three models (Arrhenius, Eyring and Ball) were used to assess the temperature-dependent degradation. Following the Arrhenius model, activation energies were ranged from 51 to 135 kJ mol(-1) for ascorbic acid and from 49 to 99 kJ mol(-1) for colour intensity. The effect of storage temperature and deaeration are the most influent factors on kinetics degradation, while the fortification revealed no significant effect on ascorbic acid content and colour intensity.

  17. Decrease of reduced glutathione in isolated rat hepatocytes caused by acrolein, acrylonitrile, and the thermal degradation products of styrene copolymers.

    PubMed

    Zitting, A; Heinonen, T

    1980-01-01

    Decrease of reduced glutathione (GSH) was induced in isolated rat hepatocytes by incubation with acrolein or acrylonitrile for 120 min or exposure to the products of oxidative thermal degradation of acrylonitrile-butadiene-styrene copolymer (ABS), styrene-acrylonitrile copolymer (SAN), and high impact polystyrene (SB). The decrease of GSH by acrolein was rapid but the cells soon recovered at acrolein concentrations of 0.025--0.25 mM. 0.5 mM acrolein depleted the cells of GSH and they were uncapable of further GSH synthesis. At concentrations of 0.25--0.5 mM concomitant lipid peroxidation impaired the integrity of the cell membranes. Also acrylonitrile induced a dose dependent GSH decrease at concentrations of 0.05--1 mM. Neither membrane damage nor lipid peroxidation was detected during 120-min incubations at these acrylonitrile concentrations. The thermal degradation products of ABS, SAN and SB caused a decrease of GSH in hepatocytes. The extent of the decrease depended on the degradation temperature and the type of the plastic. The membrane integrity was impaired in the cases where GSH was depleted almost completely; ABS degraded at 350 degrees C and SB at 250 degrees C. The measurements of lipid peroxidation by the thiobarbituric acid and the diene conjugation methods were impossible because the degradation products contained compounds which interfered with these tests.

  18. First-order kinetics analysis of monomer composition dependent polyhydroxyalkanoic acid degradation in Pseudomonas spp.

    PubMed

    Choi, Mun Hwan; Rho, Jong Kook; Lee, Ho-Joo; Song, Jae Jun; Yoon, Sung Chul; Lee, Sang Yeol

    2003-01-01

    The intracellular degradation of polyhydroxyalkanoic acid (PHA) in pseudomonads was investigated by first-order kinetics analysis using the initial rate method. One type of PHA was accumulated in five Pseudomonas spp., P. oleovorans, P. aeruginosa, P. fluorescens, P. citronellolis, and P. putida, by growing them on octanoic acid. The monomer compositions of the five PHA were not significantly different from one another: 85-90 mol % 3-hydroxyoctanoic acid (3HO), 7-12 mol % 3-hydorxycaproic acid (3HC), and 3-6 mol % 3-hydroxydecanoic acid (3HD). The first-order degradation rate constants (k(1)) for the octanoate-derived PHA (designated P(3HO)) in the five species were in a similar range between 0.060 and 0.088 h(-1). This may indicate the similar specificities of the five intracellular depolymerases. In addition, the similar k(1) among the different species may correlate with the high degree of amino acid sequence identities (over 85%) among the intracellular PHA depolymerase phaZ genes. Six other chemically different types of PHA were accumulated in P. putida from n-nonanoic acid, n-decanoic acid, 5-phenyvaleric acid, or 11-phenoxyundecanoic acid as a single or a mixed carbon source. The calculated k(1) values were characteristic to each PHA, reflecting their chemical structures. In comparison with P(3HO), an increase in the levels of the two minor monomers 3HC and 3HD as in P(21 mol % 3HC-co-56 mol % 3HO-co-23 mol % 3HD) significantly slowed the rate of intracellular degradation. From the comparison of k(1) values, it is suggested that the P. putida intracellular depolymerase is most active against P(3HO). PMID:12625741

  19. Nitrite attenuated hypochlorous acid-mediated heme degradation in hemoglobin.

    PubMed

    Lu, Naihao; Li, Jiayu; Ren, Xiaoming; Tian, Rong; Peng, Yi-Yuan

    2015-08-01

    Hypochlorous acid (HOCl) is elevated in many inflammatory diseases and causes the accumulation of free iron. Through the Fenton reaction, free iron has the ability to generate free radicals and subsequently is toxic. Recent studies have demonstrated that HOCl participates in heme destruction of hemoglobin (Hb) and free iron release. In this study, it was showed that nitrite (NO2(-)) could prevent HOCl-mediated Hb heme destruction and free iron release. Also, NO2(-) prevented HOCl-mediated loss of Hb peroxidase activity. After the NO2(-)/HOCl treatment, Tyr 42 in α-chain was found to be nitrated in Hb, attenuating the electron transferring abilities of phenolic compounds. The protective effects of NO2(-) on HOCl-induced heme destruction were attributed to its reduction of ferryl Hb and/or direct scavenging of HOCl. Therefore, NO2(-) could show protective effects in some inflammatory diseases by preventing HOCl-mediated heme destruction of hemoproteins and free iron release. PMID:26051522

  20. Degradation of fluoroquinolone antibiotics by ferrate(VI): Effects of water constituents and oxidized products.

    PubMed

    Feng, Mingbao; Wang, Xinghao; Chen, Jing; Qu, Ruijuan; Sui, Yunxia; Cizmas, Leslie; Wang, Zunyao; Sharma, Virender K

    2016-10-15

    The degradation of five fluoroquinolone (FQ) antibiotics (flumequine (FLU), enrofloxacin (ENR), norfloxacin (NOR), ofloxacin (OFL) and marbofloxacin (MAR)) by ferrate(VI) (Fe(VI)O4(2-), Fe(VI)) was examined to demonstrate the potential of this iron-based chemical oxidant to treat antibiotics in water. Experiments were conducted at different molar ratios of Fe(VI) to FQs at pH 7.0. All FQs, except FLU, were degraded within 2 min at [Fe(VI)]:[FQ] ≤ 20.0. Multiple additions of Fe(VI) improved the degradation efficiency, and provided greater degradation than a single addition of Fe(VI). The effects of anions, cations, and humic acid (HA), usually present in source waters and wastewaters, on the removal of FLU were investigated. Anions (Cl(-), SO4(2-), NO3(-), and HCO3(-)) and monovalent cations (Na(+) and K(+)) had no influence on the removal of FLU. However, multivalent cations (Ca(2+), Mg(2+), Cu(2+), and Fe(3+)) in water decreased the efficiency of FLU removal by Fe(VI). An increase in the ionic strength of the solution, and the presence of HA in the water, also decreased the percentage of FLU removed by Fe(VI). Experiments on the removal of selected FQs, present as co-existing antibiotics in pure water, river water, synthetic water and wastewater, were also conducted to demonstrate the practical application of Fe(VI) to remove the antibiotics during water treatment. The seventeen oxidized products (OPs) of FLU were identified using solid phase extraction-liquid chromatography-high-resolution mass spectrometry. The reaction pathways are proposed, and are theoretically confirmed by molecular orbital calculations.

  1. Degradation of fluoroquinolone antibiotics by ferrate(VI): Effects of water constituents and oxidized products.

    PubMed

    Feng, Mingbao; Wang, Xinghao; Chen, Jing; Qu, Ruijuan; Sui, Yunxia; Cizmas, Leslie; Wang, Zunyao; Sharma, Virender K

    2016-10-15

    The degradation of five fluoroquinolone (FQ) antibiotics (flumequine (FLU), enrofloxacin (ENR), norfloxacin (NOR), ofloxacin (OFL) and marbofloxacin (MAR)) by ferrate(VI) (Fe(VI)O4(2-), Fe(VI)) was examined to demonstrate the potential of this iron-based chemical oxidant to treat antibiotics in water. Experiments were conducted at different molar ratios of Fe(VI) to FQs at pH 7.0. All FQs, except FLU, were degraded within 2 min at [Fe(VI)]:[FQ] ≤ 20.0. Multiple additions of Fe(VI) improved the degradation efficiency, and provided greater degradation than a single addition of Fe(VI). The effects of anions, cations, and humic acid (HA), usually present in source waters and wastewaters, on the removal of FLU were investigated. Anions (Cl(-), SO4(2-), NO3(-), and HCO3(-)) and monovalent cations (Na(+) and K(+)) had no influence on the removal of FLU. However, multivalent cations (Ca(2+), Mg(2+), Cu(2+), and Fe(3+)) in water decreased the efficiency of FLU removal by Fe(VI). An increase in the ionic strength of the solution, and the presence of HA in the water, also decreased the percentage of FLU removed by Fe(VI). Experiments on the removal of selected FQs, present as co-existing antibiotics in pure water, river water, synthetic water and wastewater, were also conducted to demonstrate the practical application of Fe(VI) to remove the antibiotics during water treatment. The seventeen oxidized products (OPs) of FLU were identified using solid phase extraction-liquid chromatography-high-resolution mass spectrometry. The reaction pathways are proposed, and are theoretically confirmed by molecular orbital calculations. PMID:27429354

  2. AMINO ACIDS AND HEMOGLOBIN PRODUCTION IN ANEMIA

    PubMed Central

    Whipple, G. H.; Robscheit-Robbins, F. S.

    1940-01-01

    Certain individual amino acids when given to standard anemic dogs cause an increase in new hemoglobin production. Occasional negative experiments are recorded. Glycine, glutamic acid, aspartic acid, cystine, histidine, phenylalanine, and proline when given in 1 gm. doses daily for 2 weeks, increase hemoglobin output on the average 23 to 25 gm. above the control level. This reaction amounts to 25 to 30 per cent of the new hemoglobin produced by the feeding of 300 gm. liver daily for 2 weeks—a standard liver test. Alanine, valine, isoleucine, and arginine in the same dosage increase the hemoglobin output on the average 13 to 17 gm. per 2 weeks over the control level. Leucine, methionine, lysine, tryptophane, and tyrosine fall in a middle group with hemoglobin output of about 20 gm. Isovaleric acid, β-hydroxybutyric acid, glutaric acid, and asparagine have shown positive effects and the butyrate is unusually potent for hemoglobin production (Table 2). The isomeric and dl-synthetic forms of the amino acids are as effectively utilized in this reaction as are the natural forms. PMID:19870982

  3. Hyaluronic Acid Hydrogels with Controlled Degradation Properties for Oriented Bone Regeneration

    PubMed Central

    Patterson, J; Siew, R; Herring, SW; Lin, ASP; Guldberg, R; Stayton, PS

    2010-01-01

    Non-healing fractures can result from trauma, disease, or age-related bone loss. While many treatments focus on restoring bone volume, few try to recapitulate bone organization. However, the native architecture of bone is optimized to provide its necessary mechanical properties. Hyaluronic acid (HA) hydrogel scaffold systems with tunable degradation properties were developed for the controlled delivery of osteoinductive and angiogenic growth factors, thus affecting the quantity and quality of regenerated tissue. HA hydrogels were designed to degrade at fast, intermediate, and slow rates due to hydrolysis and further provided controlled release of cationic proteins due to electrostatic interactions. Scaffolds delivering bone morphogenetic protein-2 (BMP-2) were evaluated in a rat calvarial bone critical size defect model. BMP-2 delivery from the HA hydrogels had a clear osteoinductive effect in vivo and, for all hydrogel types, BMP-2 delivery resulted in significant mineralization compared to control hydrogels. The temporal progression of this effect could be modulated by altering the degradation rate of the scaffold. All three degradation rates tested resulted in similar amounts of mineral formation at the latest (six week) time point examined. Interestingly, however, the fastest and slowest degrading scaffolds seemed to result in more organized bone than the intermediate degrading scaffold, which was designed to degrade in 6–8 weeks to match the healing time. Additionally, healing could be enhanced by co-delivery of vascular endothelial growth factor along with BMP-2. PMID:20573393

  4. Rate Motifs Tune Auxin/Indole-3-Acetic Acid Degradation Dynamics1[OPEN

    PubMed Central

    Moss, Britney L.; Mao, Haibin; Guseman, Jessica M.; Hinds, Thomas R.; Hellmuth, Antje; Kovenock, Marlies; Noorassa, Anisa; Lanctot, Amy; Villalobos, Luz Irina A. Calderón; Zheng, Ning; Nemhauser, Jennifer L.

    2015-01-01

    Ubiquitin-mediated protein degradation is a common feature in diverse plant cell signaling pathways; however, the factors that control the dynamics of regulated protein turnover are largely unknown. One of the best-characterized families of E3 ubiquitin ligases facilitates ubiquitination of auxin (aux)/indole-3-acetic acid (IAA) repressor proteins in the presence of auxin. Rates of auxin-induced degradation vary widely within the Aux/IAA family, and sequences outside of the characterized degron (the minimum region required for auxin-induced degradation) can accelerate or decelerate degradation. We have used synthetic auxin degradation assays in yeast (Saccharomyces cerevisiae) and in plants to characterize motifs flanking the degron that contribute to tuning the dynamics of Aux/IAA degradation. The presence of these rate motifs is conserved in phylogenetically distant members of the Arabidopsis (Arabidopsis thaliana) Aux/IAA family, as well as in their putative Brassica rapa orthologs. We found that rate motifs can act by enhancing interaction between repressors and the E3, but that this is not the only mechanism of action. Phenotypes of transgenic plants expressing a deletion in a rate motif in IAA28 resembled plants expressing degron mutations, underscoring the functional relevance of Aux/IAA degradation dynamics in regulating auxin responses. PMID:26149575

  5. Rate Motifs Tune Auxin/Indole-3-Acetic Acid Degradation Dynamics.

    PubMed

    Moss, Britney L; Mao, Haibin; Guseman, Jessica M; Hinds, Thomas R; Hellmuth, Antje; Kovenock, Marlies; Noorassa, Anisa; Lanctot, Amy; Villalobos, Luz Irina A Calderón; Zheng, Ning; Nemhauser, Jennifer L

    2015-09-01

    Ubiquitin-mediated protein degradation is a common feature in diverse plant cell signaling pathways; however, the factors that control the dynamics of regulated protein turnover are largely unknown. One of the best-characterized families of E3 ubiquitin ligases facilitates ubiquitination of auxin (aux)/indole-3-acetic acid (IAA) repressor proteins in the presence of auxin. Rates of auxin-induced degradation vary widely within the Aux/IAA family, and sequences outside of the characterized degron (the minimum region required for auxin-induced degradation) can accelerate or decelerate degradation. We have used synthetic auxin degradation assays in yeast (Saccharomyces cerevisiae) and in plants to characterize motifs flanking the degron that contribute to tuning the dynamics of Aux/IAA degradation. The presence of these rate motifs is conserved in phylogenetically distant members of the Arabidopsis (Arabidopsis thaliana) Aux/IAA family, as well as in their putative Brassica rapa orthologs. We found that rate motifs can act by enhancing interaction between repressors and the E3, but that this is not the only mechanism of action. Phenotypes of transgenic plants expressing a deletion in a rate motif in IAA28 resembled plants expressing degron mutations, underscoring the functional relevance of Aux/IAA degradation dynamics in regulating auxin responses.

  6. Study of kinetics of degradation of cyclohexane carboxylic acid by acclimated activated sludge.

    PubMed

    Wang, Chunhua; Shi, Shuian; Chen, Hongyan

    2016-01-01

    Activated sludge contains complex microorganisms, which are highly effective biodegrading agents. In this study, the kinetics of biodegradation of cyclohexane carboxylic acid (CHCA) by an acclimated aerobic activated sludge were investigated. The results showed that after 180 days of acclimation, the activated sludge could steadily degrade >90% of the CHCA in 120 h. The degradation of CHCA by the acclimated activated sludge could be modeled using a first-order kinetics equation. The equations for the degradation kinetics for different initial CHCA concentrations were also obtained. The kinetics constant, kd, decreased with an increase in the CHCA concentration, indicating that, at high concentrations, CHCA had an inhibiting effect on the microorganisms in the activated sludge. The effects of pH on the degradation kinetics of CHCA were also investigated. The results showed that a pH of 10 afforded the highest degradation rate, indicating that basic conditions significantly promoted the degradation of CHCA. Moreover, it was found that the degradation efficiency for CHCA increased with an increase in temperature and concentration of dissolved oxygen under the experimental conditions.

  7. Rate Motifs Tune Auxin/Indole-3-Acetic Acid Degradation Dynamics.

    PubMed

    Moss, Britney L; Mao, Haibin; Guseman, Jessica M; Hinds, Thomas R; Hellmuth, Antje; Kovenock, Marlies; Noorassa, Anisa; Lanctot, Amy; Villalobos, Luz Irina A Calderón; Zheng, Ning; Nemhauser, Jennifer L

    2015-09-01

    Ubiquitin-mediated protein degradation is a common feature in diverse plant cell signaling pathways; however, the factors that control the dynamics of regulated protein turnover are largely unknown. One of the best-characterized families of E3 ubiquitin ligases facilitates ubiquitination of auxin (aux)/indole-3-acetic acid (IAA) repressor proteins in the presence of auxin. Rates of auxin-induced degradation vary widely within the Aux/IAA family, and sequences outside of the characterized degron (the minimum region required for auxin-induced degradation) can accelerate or decelerate degradation. We have used synthetic auxin degradation assays in yeast (Saccharomyces cerevisiae) and in plants to characterize motifs flanking the degron that contribute to tuning the dynamics of Aux/IAA degradation. The presence of these rate motifs is conserved in phylogenetically distant members of the Arabidopsis (Arabidopsis thaliana) Aux/IAA family, as well as in their putative Brassica rapa orthologs. We found that rate motifs can act by enhancing interaction between repressors and the E3, but that this is not the only mechanism of action. Phenotypes of transgenic plants expressing a deletion in a rate motif in IAA28 resembled plants expressing degron mutations, underscoring the functional relevance of Aux/IAA degradation dynamics in regulating auxin responses. PMID:26149575

  8. Precipitation of organic arsenic compounds and their degradation products during struvite formation.

    PubMed

    Lin, Jin-Biao; Yuan, Shoujun; Wang, Wei; Hu, Zhen-Hu; Yu, Han-Qing

    2016-11-01

    Roxarsone (ROX) and arsanilic acid (ASA) have been extensively used as organoarsenic animal feed additives. Organic arsenic compounds and their degradation products, arsenate (As(V)) and arsenite (As(III)), exist in the effluent from anaerobic reactors treating animal manure contaminated by ROX or ASA with ammonium (NH4(+)-N) and phosphate (PO4(3-)-P) together. Therefore, arsenic species in the effluent might be involved in the struvite formation process. In this study, the involvement of organic arsenic compounds and their degradation products As(V) and As(III) in the struvite crystallization was investigated. The results demonstrated that arsenic compounds did not substantially affect the PO4(3-)-P recovery, but confirmed the precipitation of arsenic during struvite formation. The precipitation of arsenic compounds in struvite was considerably affected by a solution pH from 9.0 to 11.0. With an increase in pH, the content of ASA and ROX in the precipitation decreased, but the contents of As(III) and As(V) increased. In addition, the arsenic content of As(V) in the struvite was higher than that of As(III), ASA and ROX. The results indicated that the struvite could be contaminated when the solution contains arsenic species, but that could be minimized by controlling the solution pH and maintaining anaerobic conditions during struvite formation. PMID:27262276

  9. Deciphering the genetic determinants for aerobic nicotinic acid degradation: the nic cluster from Pseudomonas putida KT2440.

    PubMed

    Jiménez, José I; Canales, Angeles; Jiménez-Barbero, Jesús; Ginalski, Krzysztof; Rychlewski, Leszek; García, José L; Díaz, Eduardo

    2008-08-12

    The aerobic catabolism of nicotinic acid (NA) is considered a model system for degradation of N-heterocyclic aromatic compounds, some of which are major environmental pollutants; however, the complete set of genes as well as the structural-functional relationships of most of the enzymes involved in this process are still unknown. We have characterized a gene cluster (nic genes) from Pseudomonas putida KT2440 responsible for the aerobic NA degradation in this bacterium and when expressed in heterologous hosts. The biochemistry of the NA degradation through the formation of 2,5-dihydroxypyridine and maleamic acid has been revisited, and some gene products become the prototype of new types of enzymes with unprecedented molecular architectures. Thus, the initial hydroxylation of NA is catalyzed by a two-component hydroxylase (NicAB) that constitutes the first member of the xanthine dehydrogenase family whose electron transport chain to molecular oxygen includes a cytochrome c domain. The Fe(2+)-dependent dioxygenase (NicX) converts 2,5-dihydroxypyridine into N-formylmaleamic acid, and it becomes the founding member of a new family of extradiol ring-cleavage dioxygenases. Further conversion of N-formylmaleamic acid to formic and maleamic acid is catalyzed by the NicD protein, the only deformylase described so far whose catalytic triad is similar to that of some members of the alpha/beta-hydrolase fold superfamily. This work allows exploration of the existence of orthologous gene clusters in saprophytic bacteria and some pathogens, where they might stimulate studies on their role in virulence, and it provides a framework to develop new biotechnological processes for detoxification/biotransformation of N-heterocyclic aromatic compounds.

  10. Economic aspects of amino acids production.

    PubMed

    Mueller, Udo; Huebner, Susanna

    2003-01-01

    Amino acids represent basic elements of proteins, which as a main source of nutrition themselves serve as a major reserve for maintaining essential functions of humans as well as animals. Taking the recent state of scientific knowledge into account, the industrial sector of amino acids is a priori "suitable" to a specific kind of an ecologically sound way of production, which is based on biotechnology. The following article may point out characteristics of this particular industrial sector and illustrates the applicability of the latest economic methods, founded on development of the discipline of bionics in order to describe economic aspects of amino acids markets. The several biochemical and technological fields of application of amino acids lead to specific market structures in high developed and permanently evolving systems. The Harvard tradition of industrial economics explains how market structures mould the behaviour of the participants and influences market results beyond that. A global increase in intensity of competition confirms the notion that the supply-side is characterised by asymmetric information in contrast to Kantzenbachs concept of "narrow oligopoly" with symmetrical shared knowledge about market information. Departing from this point, certain strategies of companies in this market form shall be derived. The importance of Research and Development increases rapidly and leads to innovative manufacturing methods which replace more polluting manufacturing processes like acid hydrolysis. In addition to these modifications within the production processes the article deals furthermore with the pricing based on product life cycle concept and introduces specific applications of tools like activity based costing and target costing to the field of amino acid production. The authors come to the conclusion that based on a good transferability of latest findings in bionics and ecological compatibility competitors in amino acids manufacturing are well advised

  11. Economic aspects of amino acids production.

    PubMed

    Mueller, Udo; Huebner, Susanna

    2003-01-01

    Amino acids represent basic elements of proteins, which as a main source of nutrition themselves serve as a major reserve for maintaining essential functions of humans as well as animals. Taking the recent state of scientific knowledge into account, the industrial sector of amino acids is a priori "suitable" to a specific kind of an ecologically sound way of production, which is based on biotechnology. The following article may point out characteristics of this particular industrial sector and illustrates the applicability of the latest economic methods, founded on development of the discipline of bionics in order to describe economic aspects of amino acids markets. The several biochemical and technological fields of application of amino acids lead to specific market structures in high developed and permanently evolving systems. The Harvard tradition of industrial economics explains how market structures mould the behaviour of the participants and influences market results beyond that. A global increase in intensity of competition confirms the notion that the supply-side is characterised by asymmetric information in contrast to Kantzenbachs concept of "narrow oligopoly" with symmetrical shared knowledge about market information. Departing from this point, certain strategies of companies in this market form shall be derived. The importance of Research and Development increases rapidly and leads to innovative manufacturing methods which replace more polluting manufacturing processes like acid hydrolysis. In addition to these modifications within the production processes the article deals furthermore with the pricing based on product life cycle concept and introduces specific applications of tools like activity based costing and target costing to the field of amino acid production. The authors come to the conclusion that based on a good transferability of latest findings in bionics and ecological compatibility competitors in amino acids manufacturing are well advised

  12. Degradation Network Reconstruction in Uric Acid and Ammonium Amendments in Oil-Degrading Marine Microcosms Guided by Metagenomic Data.

    PubMed

    Bargiela, Rafael; Gertler, Christoph; Magagnini, Mirko; Mapelli, Francesca; Chen, Jianwei; Daffonchio, Daniele; Golyshin, Peter N; Ferrer, Manuel

    2015-01-01

    Biostimulation with different nitrogen sources is often regarded as a strategy of choice in combating oil spills in marine environments. Such environments are typically depleted in nitrogen, therefore limiting the balanced microbial utilization of carbon-rich petroleum constituents. It is fundamental, yet only scarcely accounted for, to analyze the catabolic consequences of application of biostimulants. Here, we examined such alterations in enrichment microcosms using sediments from chronically crude oil-contaminated marine sediment at Ancona harbor (Italy) amended with natural fertilizer, uric acid (UA), or ammonium (AMM). We applied the web-based AromaDeg resource using as query Illumina HiSeq meta-sequences (UA: 27,893 open reading frames; AMM: 32,180) to identify potential catabolic differences. A total of 45 (for UA) and 65 (AMM) gene sequences encoding key catabolic enzymes matched AromaDeg, and their participation in aromatic degradation reactions could be unambiguously suggested. Genomic signatures for the degradation of aromatics such as 2-chlorobenzoate, indole-3-acetate, biphenyl, gentisate, quinoline and phenanthrene were common for both microcosms. However, those for the degradation of orcinol, ibuprofen, phenylpropionate, homoprotocatechuate and benzene (in UA) and 4-aminobenzene-sulfonate, p-cumate, dibenzofuran and phthalate (in AMM), were selectively enriched. Experimental validation was conducted and good agreement with predictions was observed. This suggests certain discrepancies in action of these biostimulants on the genomic content of the initial microbial community for the catabolism of petroleum constituents or aromatics pollutants. In both cases, the emerging microbial communities were phylogenetically highly similar and were composed by very same proteobacterial families. However, examination of taxonomic assignments further revealed different catabolic pathway organization at the organismal level, which should be considered for designing

  13. Degradation Network Reconstruction in Uric Acid and Ammonium Amendments in Oil-Degrading Marine Microcosms Guided by Metagenomic Data.

    PubMed

    Bargiela, Rafael; Gertler, Christoph; Magagnini, Mirko; Mapelli, Francesca; Chen, Jianwei; Daffonchio, Daniele; Golyshin, Peter N; Ferrer, Manuel

    2015-01-01

    Biostimulation with different nitrogen sources is often regarded as a strategy of choice in combating oil spills in marine environments. Such environments are typically depleted in nitrogen, therefore limiting the balanced microbial utilization of carbon-rich petroleum constituents. It is fundamental, yet only scarcely accounted for, to analyze the catabolic consequences of application of biostimulants. Here, we examined such alterations in enrichment microcosms using sediments from chronically crude oil-contaminated marine sediment at Ancona harbor (Italy) amended with natural fertilizer, uric acid (UA), or ammonium (AMM). We applied the web-based AromaDeg resource using as query Illumina HiSeq meta-sequences (UA: 27,893 open reading frames; AMM: 32,180) to identify potential catabolic differences. A total of 45 (for UA) and 65 (AMM) gene sequences encoding key catabolic enzymes matched AromaDeg, and their participation in aromatic degradation reactions could be unambiguously suggested. Genomic signatures for the degradation of aromatics such as 2-chlorobenzoate, indole-3-acetate, biphenyl, gentisate, quinoline and phenanthrene were common for both microcosms. However, those for the degradation of orcinol, ibuprofen, phenylpropionate, homoprotocatechuate and benzene (in UA) and 4-aminobenzene-sulfonate, p-cumate, dibenzofuran and phthalate (in AMM), were selectively enriched. Experimental validation was conducted and good agreement with predictions was observed. This suggests certain discrepancies in action of these biostimulants on the genomic content of the initial microbial community for the catabolism of petroleum constituents or aromatics pollutants. In both cases, the emerging microbial communities were phylogenetically highly similar and were composed by very same proteobacterial families. However, examination of taxonomic assignments further revealed different catabolic pathway organization at the organismal level, which should be considered for designing

  14. Degradation Network Reconstruction in Uric Acid and Ammonium Amendments in Oil-Degrading Marine Microcosms Guided by Metagenomic Data

    PubMed Central

    Bargiela, Rafael; Gertler, Christoph; Magagnini, Mirko; Mapelli, Francesca; Chen, Jianwei; Daffonchio, Daniele; Golyshin, Peter N.; Ferrer, Manuel

    2015-01-01

    Biostimulation with different nitrogen sources is often regarded as a strategy of choice in combating oil spills in marine environments. Such environments are typically depleted in nitrogen, therefore limiting the balanced microbial utilization of carbon-rich petroleum constituents. It is fundamental, yet only scarcely accounted for, to analyze the catabolic consequences of application of biostimulants. Here, we examined such alterations in enrichment microcosms using sediments from chronically crude oil-contaminated marine sediment at Ancona harbor (Italy) amended with natural fertilizer, uric acid (UA), or ammonium (AMM). We applied the web-based AromaDeg resource using as query Illumina HiSeq meta-sequences (UA: 27,893 open reading frames; AMM: 32,180) to identify potential catabolic differences. A total of 45 (for UA) and 65 (AMM) gene sequences encoding key catabolic enzymes matched AromaDeg, and their participation in aromatic degradation reactions could be unambiguously suggested. Genomic signatures for the degradation of aromatics such as 2-chlorobenzoate, indole-3-acetate, biphenyl, gentisate, quinoline and phenanthrene were common for both microcosms. However, those for the degradation of orcinol, ibuprofen, phenylpropionate, homoprotocatechuate and benzene (in UA) and 4-aminobenzene-sulfonate, p-cumate, dibenzofuran and phthalate (in AMM), were selectively enriched. Experimental validation was conducted and good agreement with predictions was observed. This suggests certain discrepancies in action of these biostimulants on the genomic content of the initial microbial community for the catabolism of petroleum constituents or aromatics pollutants. In both cases, the emerging microbial communities were phylogenetically highly similar and were composed by very same proteobacterial families. However, examination of taxonomic assignments further revealed different catabolic pathway organization at the organismal level, which should be considered for designing

  15. Degradation of trichloroethene by siderite-catalyzed hydrogen peroxide and persulfate: Investigation of reaction mechanisms and degradation products

    PubMed Central

    Yan, Ni; Liu, Fei; Xue, Qiang; Brusseau, Mark L.; Liu, Yali; Wang, Junjie

    2015-01-01

    A binary catalytic system, siderite-catalyzed hydrogen peroxide (H2O2) coupled with persulfate (S2O82−), was investigated for the remediation of trichloroethene (TCE) contamination. Batch experiments were conducted to investigate reaction mechanisms, oxidant decomposition rates, and degradation products. By using high performance liquid chromatography (HPLC) coupled with electron paramagnetic resonance (EPR), we identified four radicals (hydroxyl (HO·), sulfate (SO4−·), hydroperoxyl (HO2·), and superoxide (O2−·)) in the siderite-catalyzed H2O2-S2O82− system. In the absence of S2O82− (i.e., siderite-catalyzed H2O2), a majority of H2O2 was decomposed in the first hour of the experiment, resulting in the waste of HO·. The addition of S2O82− moderated the H2O2 decomposition rate, producing a more sustainable release of hydroxyl radicals that improved the treatment efficiency. Furthermore, the heat released by H2O2 decomposition accelerated the activation of S2O82−, and the resultant SO4−· was the primary oxidative agent during the first two hours of the reaction. Dichloroacetic acid was firstly detected by ion chromatography (IC). The results of this study indicate a new insight to the reaction mechanism for the catalytic binary H2O2-S2O82− oxidant system, and the delineation of radicals and the discovery of the chlorinated byproduct provide useful information for efficient treatment of chlorinated-solvent contamination in groundwater. PMID:26236152

  16. Biotechnological production of gluconic acid: future implications.

    PubMed

    Singh, Om V; Kumar, Raj

    2007-06-01

    Gluconic acid (GA) is a multifunctional carbonic acid regarded as a bulk chemical in the food, feed, beverage, textile, pharmaceutical, and construction industries. The favored production process is submerged fermentation by Aspergillus niger utilizing glucose as a major carbohydrate source, which accompanied product yield of 98%. However, use of GA and its derivatives is currently restricted because of high prices: about US$ 1.20-8.50/kg. Advancements in biotechnology such as screening of microorganisms, immobilization techniques, and modifications in fermentation process for continuous fermentation, including genetic engineering programmes, could lead to cost-effective production of GA. Among alternative carbohydrate sources, sugarcane molasses, grape must show highest GA yield of 95.8%, and banana must may assist reducing the overall cost of GA production. These methodologies would open new markets and increase applications of GA.

  17. [Progress in biotechnological production of pyruvic acid].

    PubMed

    Liu, Li-Ming; Li, Yin; Du, Guo-Cheng; Chen, Jian

    2002-11-01

    Pyruvate, an important organic acid, is widely used in the industries of pharmaceuticals, chemicals, agrochemicals, food additives and so on. Compared with the chemical method, biotechnological production of pyruvic acid is an alternative approach because of the low cost and high product quality. In this article, biosynthesis of pyruvate, including direct fermentative production and resting cell method as well as enzymatic method, was discussed. Furthermore, a comparison of these different methods was proposed. Since, a multi-vitamin auxotrophic strain of Torulopsis glabrata is the most competitive strain for industrial production of pyruvate, emphasis was therefore placed on the development of strains screening and fermentation optimization. Finally, some suggestions were put forward to improve the research in this field in the near future.

  18. Distribution of tannic acid degrading microorganisms in the soil and comparative study of tannase from two fungal strains.

    PubMed

    Mondal, K C; Samanta, S; Giri, S; Pati, B R

    2001-01-01

    A quantitative survey on microbial population including tannase producing organisms have been made from different soil samples. Most of the samples harbour negligible number of tannase producers in comparison to total microbial flora. Among the tannase producers, fungal members are more frequent than bacteria. Tannase production and tannic acid degradation have been studied in two newly isolated potent fungal strains. Both the strains produce maximum tannase at their stationary phases of growth. Enzymes produced by both the strains remain active within pH 3.5-6.0 and temperature 30-60 degrees C.

  19. Solanioic Acid, an Antibacterial Degraded Steroid Produced in Culture by the Fungus Rhizoctonia solani Isolated from Tubers of the Medicinal Plant Cyperus rotundus.

    PubMed

    Ratnaweera, Pamoda B; Williams, David E; Patrick, Brian O; de Silva, E Dilip; Andersen, Raymond J

    2015-05-01

    Solanioic acid (1), a degraded and rearranged steroid that exhibits in vitro antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA), has been isolated from laboratory cultures of the fungus Rhizoctonia solani obtained from tubers of the plant Cyperus rotundus collected in Sri Lanka. The structure of solanioic acid (1) was elucidated by detailed analysis of NMR data, a single crystal X-ray diffraction analysis of a reduction product 2, and Mosher ester analysis on a derivative of the natural product. Solanioic acid (1) has an unprecedented carbon skeleton. PMID:25860081

  20. Solanioic Acid, an Antibacterial Degraded Steroid Produced in Culture by the Fungus Rhizoctonia solani Isolated from Tubers of the Medicinal Plant Cyperus rotundus.

    PubMed

    Ratnaweera, Pamoda B; Williams, David E; Patrick, Brian O; de Silva, E Dilip; Andersen, Raymond J

    2015-05-01

    Solanioic acid (1), a degraded and rearranged steroid that exhibits in vitro antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA), has been isolated from laboratory cultures of the fungus Rhizoctonia solani obtained from tubers of the plant Cyperus rotundus collected in Sri Lanka. The structure of solanioic acid (1) was elucidated by detailed analysis of NMR data, a single crystal X-ray diffraction analysis of a reduction product 2, and Mosher ester analysis on a derivative of the natural product. Solanioic acid (1) has an unprecedented carbon skeleton.

  1. Degradation process of grease due to SF/sub 6/ gas dissociation products

    SciTech Connect

    Suzuki, T.; Koyama, A.; Tomimuro, S.; Yoshiba, H.

    1982-08-01

    It is known that some insulating materials are degraded due to dissociation products of SF/sub 6/ gas. Many studies related to the degradation of insulating materials have been accomplished. But no studies related to sealing materials, for instance (lubricating) grease and rubber have been made. This paper presents the degradation process of grease as follows. Properties of Lithium grease easily change in SF/sub 6/ gas including dissociation products owing to the degradation of Lithium soap used as thickner of grease. However, in the case of Bentonite grease and Urea grease, any changes of properties are not observed.

  2. Concentration Effects of Polymer Electrolyte Membrane Degradation Products on Oxygen Reduction Activity for Three Platinum Catalysts

    DOE PAGES

    Christ, J. M.; Neyerlin, K. C.; Richards, R.; Dinh, H. N.

    2014-10-04

    A rotating disk electrode (RDE) along with cyclic voltammetry (CV) and linear sweep voltammetry (LSV), were used to investigate the impact of two model compounds representing degradation products of Nafion and 3M perfluorinated sulfonic acid membranes on the electrochemical surface area (ECA) and oxygen reduction reaction (ORR) activity of polycrystalline Pt, nano-structured thin film (NSTF) Pt (3M), and Pt/Vulcan carbon (Pt/Vu) (TKK) electrodes. ORR kinetic currents (measured at 0.9 V and transport corrected) were found to decrease linearly with the log of concentration for both model compounds on all Pt surfaces studied. Ultimately, model compound adsorption effects on ECA weremore » more abstruse due to competitive organic anion adsorption on Pt surfaces superimposing with the hydrogen underpotential deposition (HUPD) region.« less

  3. Concentration Effects of Polymer Electrolyte Membrane Degradation Products on Oxygen Reduction Activity for Three Platinum Catalysts

    SciTech Connect

    Christ, J. M.; Neyerlin, K. C.; Richards, R.; Dinh, H. N.

    2014-10-04

    A rotating disk electrode (RDE) along with cyclic voltammetry (CV) and linear sweep voltammetry (LSV), were used to investigate the impact of two model compounds representing degradation products of Nafion and 3M perfluorinated sulfonic acid membranes on the electrochemical surface area (ECA) and oxygen reduction reaction (ORR) activity of polycrystalline Pt, nano-structured thin film (NSTF) Pt (3M), and Pt/Vulcan carbon (Pt/Vu) (TKK) electrodes. ORR kinetic currents (measured at 0.9 V and transport corrected) were found to decrease linearly with the log of concentration for both model compounds on all Pt surfaces studied. Ultimately, model compound adsorption effects on ECA were more abstruse due to competitive organic anion adsorption on Pt surfaces superimposing with the hydrogen underpotential deposition (HUPD) region.

  4. Control of the molecular degradation of hyaluronic acid hydrogels for tissue augmentation.

    PubMed

    Oh, Eun Ju; Kang, Sun-Woong; Kim, Byung-Soo; Jiang, Ge; Cho, Il Hwan; Hahn, Sei Kwang

    2008-09-01

    A novel protocol to control the molecular degradation of hyaluronic acid (HA) hydrogels was successfully developed for tissue augmentation applications. HA has a different conformational structure in water and organic solvent, and the carboxyl group of HA is known to be the recognition site of hyaluronidase and HA receptors. Based on these findings, HA was chemically modified by grafting adipic acid dihydrazide (ADH) to the carboxyl group of HA in the water to prepare HA-ADH(WATER) and in the mixed solvent of water and ethanol to prepare degradation-controlled HA-ADH(WATER/ETHANOL). Three kinds of HA hydrogels were prepared by the crosslinking of HA-ADH(WATER) or HA-ADH(WATER/ETHANOL) with bis(sulfosuccinimidyl) suberate, and by the crosslinking of HA-OH with divinyl sulfone (DVS). In vitro and in vivo degradation tests showed that HA-DVS hydrogels were degraded most rapidly, followed by HA-ADH(WATER) hydrogels and HA-ADH(WATER/ETHANOL) hydrogels. There was no adverse effect during and after in vivo degradation tests. All of the HA hydrogel samples appeared to be biocompatible, according to the histological analysis with hematoxylin-eosin and Alcian blue. PMID:18022803

  5. Influence of amino acids, buffers, and ph on the γ-irradiation-induced degradation of alginates.

    PubMed

    Ulset, Ann-Sissel T; Mori, Hideki; Dalheim, Marianne Ø; Hara, Masayuki; Christensen, Bjørn E

    2014-12-01

    Alginate-based biomaterials and medical devices are commonly subjected to γ-irradiation as a means of sterilization, either in the dry state or the gel (hydrated) state. In this process the alginate chains degrade randomly in a dose-dependent manner, altering alginates' material properties. The addition of free radical scavenging amino acids such as histidine and phenylalanine protects the alginate significantly against degradation, as shown by monitoring changes in the molecular weight distributions using SEC-MALLS and determining the pseudo first order rate constants of degradation. Tris buffer (0.5 M), but not acetate, citrate, or phosphate buffers had a similar effect on the degradation rate. Changes in pH itself had only marginal effects on the rate of alginate degradation and on the protective effect of amino acids. Contrary to previous reports, the chemical composition (M/G profile) of the alginates, including homopolymeric mannuronan, was unaltered following irradiation up to 10 kGy. PMID:25412478

  6. Fatty acid production in genetically modified cyanobacteria

    PubMed Central

    Liu, Xinyao; Sheng, Jie; Curtiss III, Roy

    2011-01-01

    To avoid costly biomass recovery in photosynthetic microbial biofuel production, we genetically modified cyanobacteria to produce and secrete fatty acids. Starting with introducing an acyl–acyl carrier protein thioesterase gene, we made six successive generations of genetic modifications of cyanobacterium Synechocystis sp. PCC6803 wild type (SD100). The fatty acid secretion yield was increased to 197 ± 14 mg/L of culture in one improved strain at a cell density of 1.0 × 109 cells/mL by adding codon-optimized thioesterase genes and weakening polar cell wall layers. Although these strains exhibited damaged cell membranes at low cell densities, they grew more rapidly at high cell densities in late exponential and stationary phase and exhibited less cell damage than cells in wild-type cultures. Our results suggest that fatty acid secreting cyanobacteria are a promising technology for renewable biofuel production. PMID:21482809

  7. Triacetic acid lactone production from Saccharomyces cerevisiae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Triacetic acid lactone (TAL) is a potential platform chemical produced from acetyl-CoA and malonyl-CoA by the Gerbera hybrida 2-pyrone synthase (2PS) gene. Studies are ongoing to optimize production, purification, and chemical modification of TAL, which can be used to create the commercial chemicals...

  8. Occurrence and fate of the herbicide glyphosate and its degradate aminomethylphosphonic acid in the atmosphere

    USGS Publications Warehouse

    Chang, Feng-Chih; Simcik, M.F.; Capel, P.D.

    2011-01-01

    This is the first report on the ambient levels of glyphosate, the most widely used herbicide in the United States, and its major degradation product, aminomethylphosphonic acid (AMPA), in air and rain. Concurrent, weekly integrated air particle and rain samples were collected during two growing seasons in agricultural areas in Mississippi and Iowa. Rain was also collected in Indiana in a preliminary phase of the study. The frequency of glyphosate detection ranged from 60 to 100% in both air and rain. The concentrations of glyphosate ranged from 3 and from <0.1 to 2.5 µg/L in air and rain samples, respectively. The frequency of detection and median and maximum concentrations of glyphosate in air were similar or greater to those of the other high-use herbicides observed in the Mississippi River basin, whereas its concentration in rain was greater than the other herbicides. It is not known what percentage of the applied glyphosate is introduced into the air, but it was estimated that up to 0.7% of application is removed from the air in rainfall. Glyphosate is efficiently removed from the air; it is estimated that an average of 97% of the glyphosate in the air is removed by a weekly rainfall ≥30 mm.

  9. Occurrence and fate of the herbicide glyphosate and its degradate aminomethylphosphonic acid in the atmosphere.

    PubMed

    Chang, Feng-chih; Simcik, Matt F; Capel, Paul D

    2011-03-01

    This is the first report on the ambient levels of glyphosate, the most widely used herbicide in the United States, and its major degradation product, aminomethylphosphonic acid (AMPA), in air and rain. Concurrent, weekly integrated air particle and rain samples were collected during two growing seasons in agricultural areas in Mississippi and Iowa. Rain was also collected in Indiana in a preliminary phase of the study. The frequency of glyphosate detection ranged from 60 to 100% in both air and rain. The concentrations of glyphosate ranged from <0.01 to 9.1 ng/m(3) and from <0.1 to 2.5 µg/L in air and rain samples, respectively. The frequency of detection and median and maximum concentrations of glyphosate in air were similar or greater to those of the other high-use herbicides observed in the Mississippi River basin, whereas its concentration in rain was greater than the other herbicides. It is not known what percentage of the applied glyphosate is introduced into the air, but it was estimated that up to 0.7% of application is removed from the air in rainfall. Glyphosate is efficiently removed from the air; it is estimated that an average of 97% of the glyphosate in the air is removed by a weekly rainfall ≥ 30 mm.

  10. Degradation of 3-chloro-4-hydroxybenzoic acid in biological treated effluent by gamma irradiation

    NASA Astrophysics Data System (ADS)

    Chu, Libing; Wang, Jianlong

    2016-02-01

    Gamma irradiation-induced degradation of a chlorinated aromatic compound, 3-chloro-4-hydroxybenzoic acid (CHBA) in biological treated effluent was studied and the results were compared with those obtained in deionized water. Gamma irradiation led to a complete decomposition of CHBA and a partial mineralization in the treated effluent. The removal of CHBA followed the pseudo first-order reaction kinetic model and the rate constant in the treated effluent was 1.7-3.5 times lower than that in deionized water. The CHBA degradation rate was higher at acidic condition than at neutral and alkaline conditions. The radiolytic yield, G-value for CHBA degradation was lower in the treated effluent, which decreased with increase in absorbed doses and increased with increase in initial concentrations of CHBA. The degradation mechanism of CHBA using gamma irradiation was proposed through the oxidation by -OH and reduction by eaq- and H- radicals. As exposed to gamma irradiation, dechlorination takes place rapidly and combines with the oxidation and cleavage of the aromatic ring, producing chloride ions, small carboxylic acids, acetaldehyde and other intermediates into the solution.

  11. Degradation of chloro- and methyl-substituted benzoic acids by a genetically modified microorganism

    SciTech Connect

    Mueller, R.; Deckwer, W.D.; Hecht, V.

    1996-09-05

    Degradation of 3-chlorobenzoic acid (3CB), 4-chlorobenzoic acid (4CB), and 4-methylbenzoic acid (4MB) as single substrates (carbon sources) and as a substrate mixture were studied in batch and continuous culture using the genetically modified microorganism Pseudomonas sp. B13 FR1 SN45P. The strain was able to mineralize the single compounds as well as the substrate mixture completely. Conversion of the three compounds in the substrate mixture proceeded simultaneously. Maximum specific substrate conversion rates were calculated to be 0.9 g g{sup {minus}1} h{sup {minus}1} for 3 CB and 4CB and 1.1 g g{sup {minus}1} h{sup {minus}1} for 4MB. Mass balances indicated the transient accumulation of pathway intermediates during batch cultivations. Hence, the rate limiting step in the degradative pathway is not the initial microbial attack of the original substrate or its transport through the cell membrane. Degradation rates on 3CB were comparable to those of the parent strain Pseudomonas sp. B13. The stability of the degradation pathways of strain Pseudomonas sp. B13 FR1 SN45P could be demonstrated in a continuous cultivation over 3.5 months (734 generation times) on 3CB, 4MB, and 4CB, which were used a single carbon sources one after the other.

  12. Ammonium-oxidizing bacteria facilitate aerobic degradation of sulfanilic acid in activated sludge.

    PubMed

    Chen, Gang; Ginige, Maneesha P; Kaksonen, Anna H; Cheng, Ka Yu

    2014-01-01

    Sulfanilic acid (SA) is a toxic sulfonated aromatic amine commonly found in anaerobically treated azo dye contaminated effluents. Aerobic acclimatization of SA-degrading mixed microbial culture could lead to co-enrichment of ammonium-oxidizing bacteria (AOB) because of the concomitant release of ammonium from SA oxidation. To what extent the co-enriched AOB would affect SA oxidation at various ammonium concentrations was unclear. Here, a series of batch kinetic experiments were conducted to evaluate the effect of AOB on aerobic SA degradation in an acclimatized activated sludge culture capable of oxidizing SA and ammonium simultaneously. To account for the effect of AOB on SA degradation, allylthiourea was used to inhibit AOB activity in the culture. The results indicated that specific SA degradation rate of the mixed culture was negatively correlated with the initial ammonium concentration (0-93 mM, R²= 0.99). The presence of AOB accelerated SA degradation by reducing the inhibitory effect of ammonium (≥ 10 mM). The Haldane substrate inhibition model was used to correlate substrate concentration (SA and ammonium) and oxygen uptake rate. This study revealed, for the first time, that AOB could facilitate SA degradation at high concentration of ammonium (≥ 10 mM) in an enriched activated sludge culture.

  13. Nanomechanical properties of poly(lactic-co-glycolic) acid film during degradation.

    PubMed

    Shirazi, Reyhaneh Neghabat; Aldabbagh, Fawaz; Erxleben, Andrea; Rochev, Yury; McHugh, Peter

    2014-11-01

    Despite the potential applications of poly(lactic-co-glycolic) acid (PLGA) coatings in medical devices, the mechanical properties of this material during degradation are poorly understood. In the present work, the nanomechanical properties and degradation of PLGA film were investigated. Hydrolysis of solvent-cast PLGA film was studied in buffer solution at 37 °C. The mass loss, water uptake, molecular weight, crystallinity and surface morphology of the film were tracked during degradation over 20 days. Characterization of the surface hardness and Young's modulus was performed using the nanoindentation technique for different indentation loads. The initially amorphous films were found to remain amorphous during degradation. The molecular weight of the film decreased quickly during the initial days of degradation. Diffusion of water into the film resulted in a reduction in surface hardness during the first few days, followed by an increase that was due to the surface roughness. There was a significant delay between the decrease in the mechanical properties of the film and the decrease in the molecular weight. A sudden decline in mechanical properties indicated that significant bulk degradation had occurred.

  14. Degradation behavior of hydroxyapatite/poly(lactic-co-glycolic) acid nanocomposite in simulated body fluid

    SciTech Connect

    Liuyun, Jiang; Chengdong, Xiong; Lixin, Jiang; Lijuan, Xu

    2013-10-15

    Graphical abstract: In this manuscript, we initiated a systematic study to investigate the effect of HA on thermal properties, inner structure, reduction of mechanical strength, surface morphology and the surface deposit of n-HA/PLGA composite with respect to the soaking time. The results showed that n-HA played an important role in improving the degradation behavior of n-HA/PLGA composite, which can accelerate the degradation of n-HA/PLGA composite and endow it with bioactivity, after n-HA was detached from PLGA during the degradation, so that n-HA/PLGA composite may have a more promising prospect of the clinical application than pure PLGA as bone fracture internal fixation materials, and the results would be of reference significance to predict the in vivo degradation and biological properties. - Highlights: • Effect of n-HA on degradation behavior of n-HA/PLGA composite was investigated. • Degradation behaviors of n-HA/PLGA and PLGA were carried out in SBF for 6 months. • Viscosity, thermal properties, inner structure and bending strength were tested. • n-HA can accelerate the degradation and endows it with bioactivity. - Abstract: To investigate the effect of hydroxyapatite(HA) on the degradation behavior of hydroxyapatite/poly(lactic-co-glycolic) acid (HA/PLGA) nanocomposite, the degradation experiment of n-HA/PLGA composite and pure PLGA were carried out by soaking in simulated body fluid(SBF) at 37 °C for 1, 2, 4 and 6 months. The change of intrinsic viscosity, thermal properties, inner structure, bending strength reduction, surface morphology and the surface deposit of n-HA/PLGA composite and pure PLGA with respect to the soaking time were investigated by means of UbbeloHde Viscometer, differential scanning calorimeter (DSC), scanning electron microscope(SEM), electromechanical universal tester, a conventional camera and X-ray diffraction (XRD). The results showed that n-HA played an important role in improving the degradation behavior of n

  15. Study of acaricide stability in honey. Characterization of amitraz degradation products in honey and beeswax.

    PubMed

    Korta, E; Bakkali, A; Berrueta, L A; Gallo, B; Vicente, F; Kilchenmann, V; Bogdanov, S

    2001-12-01

    A study on the possible degradation of amitraz, bromopropylate, coumaphos, chlordimeform, cymiazole, flumethrin, and tau-fluvalinate during the storage of honey was carried out by HPLC. Except amitraz, the other acaricides are stable in this medium for at least 9 months. Degradation studies of amitraz in honey and beeswax were carried out; the degradation products detected in both matrices were 2,4-dimethylphenylformamide (DMF) and N-(2,4-dimethylphenyl)-N'-methylformamidine (DPMF). The reaction rate constants and the half-lives of the amitraz degradation in honey and wax were calculated. Amitraz was nearly completely degraded within 1 day in beeswax and within 10 days in honey. When amitraz-spiked combs are recycled into new beeswax, DMF was found to be the principal degradation product left in pure wax. PMID:11743771

  16. Acid phosphatase production by recombinant Arxula adeninivorans.

    PubMed

    Minocha, Neha; Kaur, Parvinder; Satyanarayana, T; Kunze, G

    2007-08-01

    Acid phosphatase production by recombinant Arxula adeninivorans was carried out in submerged fermentation. Using the Plackett-Burman design, three fermentation variables (pH, sucrose concentration, and peptone concentration) were identified to significantly affect acid phosphatase and biomass production, and these were optimized using response surface methodology of central composite design. The highest enzyme yields were attained in the medium with 3.9% sucrose and 1.6% peptone at pH 3.8. Because of optimization, 3.86- and 4.19-fold enhancement in enzyme production was achieved in shake flasks (17,054 U g(-1) DYB) and laboratory fermenter (18,465 U g(-1) DYB), respectively. PMID:17541580

  17. Effect of self-degradation products on crystallization of protease thermolysin

    NASA Astrophysics Data System (ADS)

    Sazaki, Gen; Aoki, Satoshi; Ooshima, Hiroshi; Kato, Jyoji

    1994-05-01

    The effect of self-degradation products of protease thermolysin on the crystallization of thermolysin was investigated. Crystallizations were carried out at the concentration of the self-degradation products of 0 to 0.622 mg/ml, 5 C, and pH 7.0. The initial concentration of thermolysin was constant (1.70 +/- 0.01 mg/ml). Crystallizations were monitored by dynamic light scattering and photomicroscopy. The crystallization of thermolysin in the presence of the self-degradation products proceeded through two successive steps: the formation of primary particles and the formation of large crystals by the aggregation of the primary particles. Low concentration of the self-degradation products (0.212 mg/ml) accelerated the formation of the primary particles and also the formation of the large crystals. High concentration of the self-degradation products, however, inhibited the formation of the primary particles and their aggregation to the large crystals. As the result, a large number of small aggregates which had not grown to the large crystals were observed by photomicroscopy. An analysis of the crystals and the primary particles formed in the presence of the self-degradation products by gel filtration high performance liquid chromatography revealed that the self-degradation products are not incorporated in the primary particles, but are incorporated probably in the openings between the primary particles during the crystallization.

  18. Pyrene degradation by a Mycobacterium sp. : Identification of ring oxidation and ring fission products

    SciTech Connect

    Heitkamp, M.A.; Freeman, J.P.; Miller, D.W.; Cerniglia, C.E. )

    1988-10-01

    The degradation of pyrene, a polycyclic aromatic hydrocarbon containing four aromatic rings, by pure cultures of a Mycobacterium sp. was studied. Over 60% of ({sup 14}C)pyrene was mineralized to CO{sub 2} after 96 h of incubation at 24{degree}C. High-pressure liquid chromatography analyses showed the presence of one major and at least six other metabolites that accounted for 95% of the total organic-extractable {sup 14}C-labeled residues. Analyses by UV, infrared, mass, and nuclear magnetic resonance spectrometry and gas chromatography identified both pyrene cis- and trans-4,5-dihydrodiols and pyrenol as initial microbial ring-oxidation products of pyrene. The major metabolite, 4-phenanthroic acid, and 4-hydroxyperinaphthenone and cinnamic and phthalic acids were identified as ring fission products. {sup 18}O{sub 2} studies showed that the formation of cis- and trans-4,5-dihydrodiols were catalyzed by dioxygenase and monooxygenase enzymes, respectively. This is the first report of the chemical pathway for the microbial catabolism of pyrene.

  19. Study of the forced degradation behavior of prasugrel hydrochloride by liquid chromatography with mass spectrometry and liquid chromatography with NMR detection and prediction of the toxicity of the characterized degradation products.

    PubMed

    Singh, Dilip Kumar; Sahu, Archana; Handa, Tarun; Narayanam, Mallikarjun; Singh, Saranjit

    2015-09-01

    Prasugrel was subjected to forced degradation studies under conditions of hydrolysis (acid, base, and neutral), photolysis, oxidation, and thermal stress. The drug showed liability in hydrolytic as well as oxidative conditions, resulting in a total of four degradation products. In order to characterize the latter, initially mass fragmentation pathway of the drug was established with the help of mass spectrometry/time-of-flight, multiple stage mass spectrometry and hydrogen/deuterium exchange data. The degradation products were then separated on a C18 column using a stability-indicating volatile buffer method, which was later extended to liquid chromatography-mass spectrometry studies. The latter highlighted that three degradation products had the same molecular mass, while one was different. To characterize all, their mass fragmentation pathways were established in the same manner as the drug. Subsequently, liquid chromatography-nuclear magnetic resonance (NMR) spectroscopy data were collected. Proton and correlation liquid chromatography with NMR spectroscopy studies highlighted existence of diastereomeric behavior in one pair of degradation products. Lastly, toxicity prediction by computer-assisted technology (TOPKAT) and deductive estimation of risk from existing knowledge (DEREK) software were employed to assess in silico toxicity of the characterized degradation products.

  20. Effects of environmental conditions on aerobic degradation of a commercial naphthenic acid.

    PubMed

    Kinley, Ciera M; Gaspari, Daniel P; McQueen, Andrew D; Rodgers, John H; Castle, James W; Friesen, Vanessa; Haakensen, Monique

    2016-10-01

    Naphthenic acids (NAs) are problematic constituents in energy-derived waters, and aerobic degradation may provide a strategy for mitigating risks to aquatic organisms. The overall objective of this study was to determine the influence of concentrations of N (as ammonia) and P (as phosphate), and DO, as well as pH and temperatures on degradation of a commercial NA in bench-scale reactors. Commercial NAs provided replicable compounds necessary to compare influences of environmental conditions on degradation. NAs were quantified using high performance liquid chromatography. Microbial diversity and relative abundance were measured in treatments as explanatory parameters for potential effects of environmental conditions on microbial populations to support analytically measured NA degradation. Environmental conditions that positively influenced degradation rates of Fluka NAs included nutrients (C:N 10:1-500:1, C:P 100:1-5000:1), DO (4.76-8.43 mg L(-1)), pH (6-8), and temperature (5-25 °C). Approximately 50% removal of 61 ± 8 mg L(-1) was achieved in less than 2 d after NA introduction, achieving the method detection limit (5 mg L(-1)) by day 6 of the experiment in treatments with a C:N:P ratio of 100:10:1, DO > 8 mg L(-1), pH ∼8-9, and temperatures >23 °C. Microbial diversity was lowest in lower temperature treatments (6-16 °C), which may have resulted in observed slower NA degradation. Based on results from this study, when macro- and micronutrients were available, DO, pH, and temperature (within environmentally relevant ranges) influenced rates of aerobic degradation of Fluka NAs. This study could serve as a model for systematically evaluating environmental factors that influence NA degradation in field scenarios.

  1. Effects of environmental conditions on aerobic degradation of a commercial naphthenic acid.

    PubMed

    Kinley, Ciera M; Gaspari, Daniel P; McQueen, Andrew D; Rodgers, John H; Castle, James W; Friesen, Vanessa; Haakensen, Monique

    2016-10-01

    Naphthenic acids (NAs) are problematic constituents in energy-derived waters, and aerobic degradation may provide a strategy for mitigating risks to aquatic organisms. The overall objective of this study was to determine the influence of concentrations of N (as ammonia) and P (as phosphate), and DO, as well as pH and temperatures on degradation of a commercial NA in bench-scale reactors. Commercial NAs provided replicable compounds necessary to compare influences of environmental conditions on degradation. NAs were quantified using high performance liquid chromatography. Microbial diversity and relative abundance were measured in treatments as explanatory parameters for potential effects of environmental conditions on microbial populations to support analytically measured NA degradation. Environmental conditions that positively influenced degradation rates of Fluka NAs included nutrients (C:N 10:1-500:1, C:P 100:1-5000:1), DO (4.76-8.43 mg L(-1)), pH (6-8), and temperature (5-25 °C). Approximately 50% removal of 61 ± 8 mg L(-1) was achieved in less than 2 d after NA introduction, achieving the method detection limit (5 mg L(-1)) by day 6 of the experiment in treatments with a C:N:P ratio of 100:10:1, DO > 8 mg L(-1), pH ∼8-9, and temperatures >23 °C. Microbial diversity was lowest in lower temperature treatments (6-16 °C), which may have resulted in observed slower NA degradation. Based on results from this study, when macro- and micronutrients were available, DO, pH, and temperature (within environmentally relevant ranges) influenced rates of aerobic degradation of Fluka NAs. This study could serve as a model for systematically evaluating environmental factors that influence NA degradation in field scenarios. PMID:27459161

  2. Uptake of 8:2 perfluoroalkyl phosphate diester and its degradation products by carrot and lettuce from compost-amended soil.

    PubMed

    Bizkarguenaga, E; Zabaleta, I; Prieto, A; Fernández, L A; Zuloaga, O

    2016-06-01

    The present work studied the uptake of 8:2 perfluoroalkyl phosphate diester (diPAP) by two different crops (lettuce and carrot) and two different amended soils. Firstly, the possible degradation of 8:2 diPAP in the absence of crop was studied and 8:2 monoPAP (monophosphate), 8:2 FTCA (saturated fluorotelomer carboxylate), 8:2 FTUCA (unsaturated fluorotelomer carboxylate), 7:3 FTCA (saturated fluorotelomer carboxylate), PFHpA (perfluoroheptanoic acid), PFHxA (perfluorohexanoic acid) and PFOA (perfluorooctanoic acid) were detected. In the presence of crops, different degradation products were detected in the soil and, while PFNA (perfluorononanoic acid), PFHpA, PFHxA, PFPeA (perfluoropentacoic acid), PFBA (perfluorobutanoic acid), 7:3 FTCA and PFOA were determined in the cultivation media when carrot was grown, PFOA was the only degradation product detected in the case of lettuce experiments. Regarding the uptake in carrot, all the degradation products except 7:3 FTCA were translocated from the soil to the carrot. Carrot core, peel and leaves bioconcentration factors, BCFs, were determined for 8:2 diPAP and its degradation products. Values lower than method detection limits for core and low BCFs in peel (0.025-0.042) and leaves (0.028-0.049) were achieved for 8:2 diPAP. Regarding to the degradation products, the higher their water solubility, the higher the plant translocation. In this sense, the lower the carbon chain length of PFCAs, the higher the BCFs determined (PFBA > PFHxA > PFHpA > PFOA > PFNA). In general, lower total BCFs were achieved when the total organic carbon of the soils increased. For lettuce experiments, 8:2 diPAP (0.04-0.18) and PFOA (0.28-1.57) were only determined in lettuce heart. PMID:26991379

  3. Degradation products from consumer nanocomposites - a case study on quantum dot lighting

    PubMed Central

    Liu, Jingyu; Katahara, John; Li, Guanglai; Coe-Sullivan, Seth; Hurt, Robert H.

    2012-01-01

    Most nanomaterials enter the natural environment as nano-enabled products, which are typically composites with primary nanoparticles bound on substrates or embedded in liquid or solid matrices. The environmental risks associated with these products are expected to differ from those associated with the as-produced particles. This article presents a case study on the end-of-life emission of a commercial prototype polymer/quantum-dot (QD) composite used in solid-state lighting for homes. We report the extent of cadmium release upon exposure to a series of environmental and biological simulant fluids, and track the loss of QD-characteristic fluorescence as a marker for chemical damage to the CdSe/ZnS nanoparticles. Measured cadmium releases after 30-day exposure range from 0.007-1.2 mg/g of polymer, and the higher values arise for low-pH simulants containing nitric or gastric acid. Centrifugal ultrafiltration and ICP was used to distinguish soluble cadmium from particulate forms. The leachate is found to contain soluble metals with no evidence of free QDs or QD-containing polymeric debris. The absence of free nanoparticles suggests that this product does not raise nanotechnology-specific environmental issues associated with degradation and leaching, but is more usefully regarded as a conventional chemical product that is a potential source of small amounts of soluble cadmium. PMID:22352378

  4. Imprinted sol-gel materials for monitoring degradation products in automotive oils by shear transverse wave.

    PubMed

    Mujahid, Adnan; Afzal, Adeel; Glanzing, Gerd; Leidl, Anton; Lieberzeit, Peter A; Dickert, Franz L

    2010-08-18

    Titania sol-gel layers imprinted with capric acid have been used as synthetic receptors for highly sensitive detection of oxidized products resulting from degradation of automotive engine oil. These layers have been applied as sensitive coating material on shear transverse wave (STW) resonators of frequencies ranging from 100 MHz to 430 MHz. A relatively small size of STW resonators, i.e. about 2 mm for 430 MHz makes these devices extremely useful while considering the concept of miniaturization. It has been proved experimentally that by increasing fundamental resonance frequency of these devices, a very high sensor response i.e. 22 kHz up to 460 kHz can be generated. The geometry of long chain capric acid fits best as recognition element in the synthesis of imprinted TiO(2) network. The thin titania layers coated on transducer surface provide excellent diffusion pathways to oxidized products of waste engine oil for selective and reversible re-inclusion i.e. recovery time of 30 min. Viscosity effects of oxidized engine oil can be minimized by shear waves which do not dissipate considerable amount of energy that ensure smooth liquid phase operation. Different oxidized products i.e. carbonic acids and esters can be characterized in lubricant via infra-red (IR) spectroscopy. The increasing IR absorbance of different waste oil samples is a clear indication of increasing concentration of carbonyl group. The IR absorbance of carbonyl groups is directly correlated to the age of respective waste engine oil samples and a quantitative relationship between sensor responses from STWs and IR absorbance was also developed.

  5. Pyrimidine degradation influences germination seedling growth and production of Arabidopsis seeds

    PubMed Central

    Cornelius, Stefanie; Witz, Sandra; Rolletschek, Hardy; Möhlmann, Torsten

    2011-01-01

    PYD1 (dihydropyrimidine dehydogenase) initiates the degradation of pyrimidine nucleobases and is located in plastids. In this study, a physiological analysis of PYD1 employing T-DNA knockout mutants and overexpressors was carried out. PYD1 knockout mutants were restricted in degradation of exogenously provided uracil and accumulated high uracil levels in plant organs throughout development, especially in dry seeds. Moreover, PYD1 knockout mutants showed delayed germination which was accompanied by low invertase activity and decreased monosaccharide levels. Abscisic acid (ABA) is an important regulator of seed germination, and ABA-responsive genes were deregulated in PYD1 knockout mutants. Together with an observed increased PYD1 expression in wild-type seedlings upon ABA treatment, an interference of PYD1 with ABA signalling can be assumed. Constitutive PYD1 overexpression mutants showed increased growth and higher seed number compared with wild-type and knockout mutant plants. During senescence PYD1 expression increased to allow uracil catabolism. From this it is concluded that early in development and during seed production PYD1 is needed to balance pyrimidine catabolism versus salvage. PMID:21865177

  6. Maleimides in recent sediments - Using chlorophyll degradation products for palaeoenvironmental reconstructions

    NASA Astrophysics Data System (ADS)

    Naeher, Sebastian; Schaeffer, Philippe; Adam, Pierre; Schubert, Carsten J.

    2013-10-01

    Maleimides (transformation products of chlorophylls and bacteriochlorophylls) were studied in recent sediments from the Swiss lake Rotsee and the Romanian Black Sea Shelf to investigate chlorophyll degradation, the role of oxygen in maleimide formation, and to identify their sources. Naturally occurring maleimides (i.e. "free" maleimides) and maleimides obtained after chromic acid oxidation of sediment extracts (i.e. "bound" maleimides) were analysed. 2-Methyl-maleimide (Me,H maleimide), 2,3-dimethyl-maleimide (Me,Me maleimide), 2-methyl-3-vinyl-maleimide (Me,vinyl maleimide), 2-methyl-3-ethyl-maleimide (Me,Et maleimide) and traces of 2-methyl-3-iso-butyl-maleimide (Me,i-Bu maleimide) occurred naturally in the sediment with a large predominance of the Me,Et homologue. Tetrapyrrolic pigments related to chlorophylls were the main source of maleimides, although variable contributions of other sources such as cytochromes and/or phycobilins cannot be completely ruled out. The predominant Me,Et maleimide and Me,vinyl maleimide most likely originate mainly from chlorophyll a related pigments. The same holds for Me,H maleimide, which might be formed following degradation of ring E from the tetrapyrrolic nucleus. Alternatively, Me,H maleimide and Me,Me maleimides might be formed by a recently discovered transformation pathway involving the oxidation of vinylic chlorophyll substituents and the formation of an aldehyde intermediate. 2-Methyl-3-n-propyl-maleimide (Me,n-Pr maleimide) and Me,i-Bu maleimide arising from bacteriochlorophyll related pigments traced the presence of phototrophic sulfur bacteria (Chlorobi), indicating photic zone euxinic and anoxic conditions in Rotsee during the last 150 years and throughout the Black Sea history, including the limnic phase of the Black Sea (Unit 3). Some other minor maleimides with specific alkylation pattern also originate from bacteriochlorophylls, while the source of others could not be identified. Free maleimides were mainly

  7. An assessment of potential degradation products in the gas-phase reactions of alternative fluorocarbons in the troposphere

    NASA Technical Reports Server (NTRS)

    Niki, Hiromi

    1990-01-01

    Tropospheric chemical transformations of alternative hydrofluorocarbons (HCF's) and hydrochlorofluorocarbons (HCFC's) are governed by hydroxyl radical initiated oxidation processes, which are likely to be analogous to those known for alkanes and chloroalkanes. A schematic diagram is used to illustrate plausible reaction mechanisms for their atmospheric degradation, where R, R', and R'' denote the F- and/or Cl-substituted alkyl groups derived from HCF's and HCFC's subsequent th the initial H atom abstraction by HO radicals. At present, virtually no kinetic data exist for the majority of these reactions, particularly for those involving RO. Potential degradation intermediates and final products include a large variety of fluorine- and/or chlorine-containing carbonyls, acids, peroxy acids, alcohols, hydrogen peroxides, nitrates and peroxy nitrates, as summarized in the attached table. Probably atmospheric lifetimes of these compounds were also estimated. For some carbonyl and nitrate products shown in this table, there seem to be no significant gas-phase removal mechanisms. Further chemical kinetics and photochemical data are needed to quantitatively assess the atmospheric fate of HCF's and HCFC's, and of the degradation products postulated in this report.

  8. 40 CFR 721.10125 - Alkenedioic acid, dialkyl ester, reaction products with polyaminocarbomonocycle and alkenoic acid...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., reaction products with polyaminocarbomonocycle and alkenoic acid alkyl ester (generic). 721.10125 Section... Substances § 721.10125 Alkenedioic acid, dialkyl ester, reaction products with polyaminocarbomonocycle and.... (1) The chemical substances identified generically as alkenedioic acid, dialkyl ester,...

  9. 40 CFR 721.10125 - Alkenedioic acid, dialkyl ester, reaction products with polyaminocarbomonocycle and alkenoic acid...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., reaction products with polyaminocarbomonocycle and alkenoic acid alkyl ester (generic). 721.10125 Section... Substances § 721.10125 Alkenedioic acid, dialkyl ester, reaction products with polyaminocarbomonocycle and.... (1) The chemical substances identified generically as alkenedioic acid, dialkyl ester,...

  10. 40 CFR 721.10125 - Alkenedioic acid, dialkyl ester, reaction products with polyaminocarbomonocycle and alkenoic acid...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., reaction products with polyaminocarbomonocycle and alkenoic acid alkyl ester (generic). 721.10125 Section... Substances § 721.10125 Alkenedioic acid, dialkyl ester, reaction products with polyaminocarbomonocycle and.... (1) The chemical substances identified generically as alkenedioic acid, dialkyl ester,...

  11. 40 CFR 721.10125 - Alkenedioic acid, dialkyl ester, reaction products with polyaminocarbomonocycle and alkenoic acid...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., reaction products with polyaminocarbomonocycle and alkenoic acid alkyl ester (generic). 721.10125 Section... Substances § 721.10125 Alkenedioic acid, dialkyl ester, reaction products with polyaminocarbomonocycle and.... (1) The chemical substances identified generically as alkenedioic acid, dialkyl ester,...

  12. 40 CFR 721.10125 - Alkenedioic acid, dialkyl ester, reaction products with polyaminocarbomonocycle and alkenoic acid...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., reaction products with polyaminocarbomonocycle and alkenoic acid alkyl ester (generic). 721.10125 Section... Substances § 721.10125 Alkenedioic acid, dialkyl ester, reaction products with polyaminocarbomonocycle and.... (1) The chemical substances identified generically as alkenedioic acid, dialkyl ester,...

  13. Photocatalytic degradation of commercially sourced naphthenic acids by TiO2-graphene composite nanomaterial.

    PubMed

    Liu, Juncheng; Wang, Lin; Tang, Jingchun; Ma, Jianli

    2016-04-01

    Naphthenic acids (NAs) are a major contributor to the toxicity in oil sands process-affected water (OSPW), which is produced by hot water extraction of bitumen. NAs are extremely difficult to be degraded due to its complex ring and side chain structure. Photocatalysis is recognized as a promising technology in the removal of refractory organic pollutants. In this work, TiO2-graphene (P25-GR) composites were synthesized by means of solvothermal method. The results showed that P25-GR composite exhibited better photocatalytic activity than pure P25. The removal efficiency of naphthenic acids in acid solution was higher than that in neutral and alkaline solutions. It was the first report ever known on the photodegradation of NAs based on graphene, and this process achieved a higher removal rate than other photocatalysis degradation of NAs in a shorter reaction time. LC/MS analysis showed that macromolecular NAs (carbon number 17-22, z value -2) were easy to be degraded than the micromolecular ones (carbon number 11-16, z value -2). Furthermore, the reactive oxygen species that play the main role in the photocatalysis system were studied. It was found that holes and ·OH were the main reactive species in the UV/P25-GR photocatalysis system. Given the high removal efficiency of refractory organic pollutants and the short degradation time, photodegradation based on composite catalysts has a broad and practical prospect. The study on the photodegradation of commercially sourced NAs may provide a guidance for the degradation of OSPW NAs by this method.

  14. Culturing oil sands microbes as mixed species communities enhances ex situ model naphthenic acid degradation.

    PubMed

    Demeter, Marc A; Lemire, Joseph A; Yue, Gordon; Ceri, Howard; Turner, Raymond J

    2015-01-01

    Oil sands surface mining for bitumen results in the formation of oil sands process water (OSPW), containing acutely toxic naphthenic acids (NAs). Potential exists for OSPW toxicity to be mitigated by aerobic degradation of the NAs by microorganisms indigenous to the oil sands tailings ponds, the success of which is dependent on the methods used to exploit the metabolisms of the environmental microbial community. Having hypothesized that the xenobiotic tolerant biofilm mode-of-life may represent a feasible way to harness environmental microbes for ex situ treatment of OSPW NAs, we aerobically grew OSPW microbes as single and mixed species biofilm and planktonic cultures under various conditions for the purpose of assaying their ability to tolerate and degrade NAs. The NAs evaluated were a diverse mixture of eight commercially available model compounds. Confocal microscopy confirmed the ability of mixed and single species OSPW cultures to grow as biofilms in the presence of the NAs evaluated. qPCR enumeration demonstrated that the addition of supplemental nutrients at concentrations of 1 g L(-1) resulted in a more numerous population than 0.001 g L(-1) supplementation by approximately 1 order of magnitude. GC-FID analysis revealed that mixed species cultures (regardless of the mode of growth) are the most effective at degrading the NAs tested. All constituent NAs evaluated were degraded below detectable limits with the exception of 1-adamantane carboxylic acid (ACA); subsequent experimentation with ACA as the sole NA also failed to exhibit degradation of this compound. Single species cultures degraded select few NA compounds. The degradation trends highlighted many structure-persistence relationships among the eight NAs tested, demonstrating the effect of side chain configuration and alkyl branching on compound recalcitrance. Of all the isolates, the Rhodococcus spp. degraded the greatest number of NA compounds, although still less than the mixed species cultures

  15. Culturing oil sands microbes as mixed species communities enhances ex situ model naphthenic acid degradation

    PubMed Central

    Demeter, Marc A.; Lemire, Joseph A.; Yue, Gordon; Ceri, Howard; Turner, Raymond J.

    2015-01-01

    Oil sands surface mining for bitumen results in the formation of oil sands process water (OSPW), containing acutely toxic naphthenic acids (NAs). Potential exists for OSPW toxicity to be mitigated by aerobic degradation of the NAs by microorganisms indigenous to the oil sands tailings ponds, the success of which is dependent on the methods used to exploit the metabolisms of the environmental microbial community. Having hypothesized that the xenobiotic tolerant biofilm mode-of-life may represent a feasible way to harness environmental microbes for ex situ treatment of OSPW NAs, we aerobically grew OSPW microbes as single and mixed species biofilm and planktonic cultures under various conditions for the purpose of assaying their ability to tolerate and degrade NAs. The NAs evaluated were a diverse mixture of eight commercially available model compounds. Confocal microscopy confirmed the ability of mixed and single species OSPW cultures to grow as biofilms in the presence of the NAs evaluated. qPCR enumeration demonstrated that the addition of supplemental nutrients at concentrations of 1 g L-1 resulted in a more numerous population than 0.001 g L-1 supplementation by approximately 1 order of magnitude. GC-FID analysis revealed that mixed species cultures (regardless of the mode of growth) are the most effective at degrading the NAs tested. All constituent NAs evaluated were degraded below detectable limits with the exception of 1-adamantane carboxylic acid (ACA); subsequent experimentation with ACA as the sole NA also failed to exhibit degradation of this compound. Single species cultures degraded select few NA compounds. The degradation trends highlighted many structure-persistence relationships among the eight NAs tested, demonstrating the effect of side chain configuration and alkyl branching on compound recalcitrance. Of all the isolates, the Rhodococcus spp. degraded the greatest number of NA compounds, although still less than the mixed species cultures

  16. Antagonism between lipid-derived reactive carbonyls and phenolic compounds in the Strecker degradation of amino acids.

    PubMed

    Delgado, Rosa M; Hidalgo, Francisco J; Zamora, Rosario

    2016-03-01

    The Strecker-type degradation of phenylalanine in the presence of 2-pentanal and phenolic compounds was studied to investigate possible interactions that either promote or inhibit the formation of Strecker aldehydes in food products. Phenylacetaldehyde formation was promoted by 2-pentenal and also by o- and p-diphenols, but not by m-diphenols. This is consequence of the ability of phenolic compounds to be converted into reactive carbonyls and produce the Strecker degradation of the amino acid. When 2-pentenal and phenolic compounds were simultaneously present, an antagonism among them was observed. This antagonism is suggested to be a consequence of the ability of phenolic compounds to either react with both 2-pentenal and phenylacetaldehyde, or compete with other carbonyl compounds for the amino acids, a function that is determined by their structure. All these results suggest that carbonyl-phenol reactions may be used to modulate flavor formation produced in food products by lipid-derived reactive carbonyls. PMID:26471665

  17. Data of thermal degradation and dynamic mechanical properties of starch-glycerol based films with citric acid as crosslinking agent.

    PubMed

    González Seligra, Paula; Medina Jaramillo, Carolina; Famá, Lucía; Goyanes, Silvia

    2016-06-01

    Interest in biodegradable edible films as packaging or coating has increased because their beneficial effects on foods. In particular, food products are highly dependents on thermal stability, integrity and transition process temperatures of the packaging. The present work describes a complete data of the thermal degradation and dynamic mechanical properties of starch-glycerol based films with citric acid (CA) as crosslinking agent described in the article titled: "Biodegradable and non-retrogradable eco-films based on starch-glycerol with citric acid as crosslinking agent" González Seligra et al. (2016) [1]. Data describes thermogravimetric and dynamical mechanical experiences and provides the figures of weight loss and loss tangent of the films as a function of the temperature.

  18. Data of thermal degradation and dynamic mechanical properties of starch–glycerol based films with citric acid as crosslinking agent

    PubMed Central

    González Seligra, Paula; Medina Jaramillo, Carolina; Famá, Lucía; Goyanes, Silvia

    2016-01-01

    Interest in biodegradable edible films as packaging or coating has increased because their beneficial effects on foods. In particular, food products are highly dependents on thermal stability, integrity and transition process temperatures of the packaging. The present work describes a complete data of the thermal degradation and dynamic mechanical properties of starch–glycerol based films with citric acid (CA) as crosslinking agent described in the article titled: “Biodegradable and non-retrogradable eco-films based on starch–glycerol with citric acid as crosslinking agent” González Seligra et al. (2016) [1]. Data describes thermogravimetric and dynamical mechanical experiences and provides the figures of weight loss and loss tangent of the films as a function of the temperature. PMID:27158645

  19. Data of thermal degradation and dynamic mechanical properties of starch-glycerol based films with citric acid as crosslinking agent.

    PubMed

    González Seligra, Paula; Medina Jaramillo, Carolina; Famá, Lucía; Goyanes, Silvia

    2016-06-01

    Interest in biodegradable edible films as packaging or coating has increased because their beneficial effects on foods. In particular, food products are highly dependents on thermal stability, integrity and transition process temperatures of the packaging. The present work describes a complete data of the thermal degradation and dynamic mechanical properties of starch-glycerol based films with citric acid (CA) as crosslinking agent described in the article titled: "Biodegradable and non-retrogradable eco-films based on starch-glycerol with citric acid as crosslinking agent" González Seligra et al. (2016) [1]. Data describes thermogravimetric and dynamical mechanical experiences and provides the figures of weight loss and loss tangent of the films as a function of the temperature. PMID:27158645

  20. A comparative study on the degradation of gallic acid by Aspergillus oryzae and Phanerochaete chrysosporium.

    PubMed

    Guo, Danzhao; Zhang, Zhicai; Liu, Dan; Zheng, Huihua; Chen, Hui; Chen, Keping

    2014-01-01

    Recently, as an emerging persistent dissolved organic pollutant (DOP), gallic acid (GA) and its efficient decomposition methods have received global attention. The present work aimed to compare the effect of Aspergillus oryzae 5992 and Phanerochaete chrysosporium 40719 on degradation of different concentrations of GA. The A. oryzae grew well and achieved a GA removal rate up to 99% in media containing 1-4% GA, much higher than P. chrysosporium. The activity of laccase and lignin peroxidase excreted by A. oryzae was higher than that by P. chrysosporium in the presence of GA. Based on the results of high-performance liquid chromatography-electrospray ionization-mass spectrometry, three relevant intermediate metabolites were determined as progallin A, methyl gallate, and pyrogallic acid, implying that A. oryzae could not degrade GA unless the carboxyl in the molecule was protected or removed. In view of the ability of A. oryzae to accommodate a high concentration of GA and achieve a high removal rate, as well as the significantly different enzyme activities involved in GA degradation and the underlying mechanisms between the two fungal strains, A. oryzae is proven to be a superior strain for the degradation of DOP.

  1. Extraction chemistry of fermentation product carboxylic acid

    SciTech Connect

    Kertes, A.S.; King, C.J.

    1986-02-01

    Within the framework of a program aiming to improve the existing extractive recovery technology of fermentation products, the state of the art is critically reviewed. The acids under consideration are propionic, lactic, pyruvic, succinic, fumaric, maleic, malic, itaconic, tartaric, citric, and isocitric, all obtained by the aerobic fermentation of glucose via the glycolytic pathway and glyoxylate bypass. With no exception, it is the undissociated monomeric acid that is extracted into carbon-bonded and phosphorus-bonded oxygen donor extractants. In the organic phase, the acids are usually dimerized. The extractive transfer process obeys the Nernst law, and the measured partition coefficients range from about 0.003 for aliphatic hydrocarbons to about 2 to 3 for aliphatic alcohols and ketones to about 10 or more for organophosphates. Equally high distribution ratios are measured when long-chain tertiary amines are employed as extractants, forming bulky salts preferentially soluble in the organic phase. 123 references.

  2. Safety and efficacy evaluation of aqueous citric acid to degrade B-aflatoxins in maize.

    PubMed

    Méndez-Albores, A; Arámbula-Villa, G; Loarca-Piña, M G F; Castaño-Tostado, E; Moreno-Martínez, E

    2005-02-01

    Chemical inactivation of aflatoxin B1 (AFB1) and aflatoxin B2 (AFB2) in maize grain by means of 1N aqueous citric acid was confirmed by the AFLATEST immunoaffinity column method, high performance liquid chromatography (HPLC), and the Ames test (Salmonella-microsomal screening system). The AFLATEST assay showed that aflatoxins in the maize grain with an initial concentration of 29 ng/g were completely degraded and 96.7% degradation occurred in maize contaminated with 93 ng/g when treated with the aqueous citric acid. Aflatoxin fluorescence strength of acidified samples was much weaker than untreated samples as observed in HPLC chromatograms. On the other hand, the Ames test results indicated that the mutagenic activity of acidified samples was greatly reduced compared with that of untreated samples based on his- --> his+ reversions in the Salmonella TA100 strain. Chemical inactivation appears to be a promising method of removing aflatoxin from food commodities.

  3. Kinetics and Quantitative Structure—Activity Relationship Study on the Degradation Reaction from Perfluorooctanoic Acid to Trifluoroacetic Acid

    PubMed Central

    Gong, Chen; Sun, Xiaomin; Zhang, Chenxi; Zhang, Xue; Niu, Junfeng

    2014-01-01

    Investigation of the degradation kinetics of perfluorooctanoic acid (PFOA) has been carried out to calculate rate constants of the main elementary reactions using the multichannel Rice-Ramsperger-Kassel-Marcus theory and canonical variational transition state theory with small-curvature tunneling correction over a temperature range of 200~500 K. The Arrhenius equations of rate constants of elementary reactions are fitted. The decarboxylation is role step in the degradation mechanism of PFOA. For the perfluorinated carboxylic acids from perfluorooctanoic acid to trifluoroacetic acid, the quantitative structure–activity relationship of the decarboxylation was analyzed with the genetic function approximation method and the structure–activity model was constructed. The main parameters governing rate constants of the decarboxylation reaction from the eight-carbon chain to the two-carbon chain were obtained. As the structure–activity model shows, the bond length and energy of C1–C2 (RC1–C2 and EC1–C2) are positively correlated to rate constants, while the volume (V), the energy difference between EHOMO and ELUMO (ΔE), and the net atomic charges on atom C2 (QC2) are negatively correlated. PMID:25196516

  4. Kinetics and quantitative structure-activity relationship study on the degradation reaction from perfluorooctanoic acid to trifluoroacetic acid.

    PubMed

    Gong, Chen; Sun, Xiaomin; Zhang, Chenxi; Zhang, Xue; Niu, Junfeng

    2014-08-14

    Investigation of the degradation kinetics of perfluorooctanoic acid (PFOA) has been carried out to calculate rate constants of the main elementary reactions using the multichannel Rice-Ramsperger-Kassel-Marcus theory and canonical variational transition state theory with small-curvature tunneling correction over a temperature range of 200~500 K. The Arrhenius equations of rate constants of elementary reactions are fitted. The decarboxylation is role step in the degradation mechanism of PFOA. For the perfluorinated carboxylic acids from perfluorooctanoic acid to trifluoroacetic acid, the quantitative structure-activity relationship of the decarboxylation was analyzed with the genetic function approximation method and the structure-activity model was constructed. The main parameters governing rate constants of the decarboxylation reaction from the eight-carbon chain to the two-carbon chain were obtained. As the structure-activity model shows, the bond length and energy of C1-C2 (RC1-C2 and EC1-C2) are positively correlated to rate constants, while the volume (V), the energy difference between EHOMO and ELUMO (ΔE), and the net atomic charges on atom C2 (QC2) are negatively correlated.

  5. Plasmid as a measure of microbial degradation capacity for 2,4-dichlorophenoxyacetic acid.

    PubMed

    Chong, Nyuk-Min; Chang, Hung-Wei

    2009-02-01

    The purpose of this research was to pursuit the quantification of microbial degradation capacity for 2,4-dichlorophenoxyacetic acid (2,4-D) by detecting and quantifying a prominent 2,4-D degradation encoding plasmid. Batch reactor acclimation, de-acclimation, and re-acclimation tests were conducted during which periods the courses of 2,4-D dissipation and plasmid evolution were quantitatively measured. Pure cultures of bacterial strains were detected to give rise to a plasmid approximately the size of 90 kb after acclimation. The 90 kb plasmid content of Arthrobacter sp. increased when degradation occurred after acclimation, with a rate that corresponded closely to the degradation rate. During de-acclimation, plasmid content declined exponentially at a half-life of approximately 3.5 days. Re-acclimation saw a renewed induction of plasmid, but substrate consumption limited the rise of plasmid to a level much lower than after the first acclimation. This research recommends a method for measuring the microbial degradation capability for a xenobiotic.

  6. Microbial degradation of chelating agents used in detergents with special reference to nitrilotriacetic acid (NTA).

    PubMed

    Egli, T; Bally, M; Uetz, T

    1990-01-01

    The extensive use of phosphate-based detergents and agricultural fertilizers is one of the main causes of the world-wide eutrophication of rivers and lakes. To ameliorate such problems partial or total substitution of phosphates in laundry detergents by synthetic, non-phosphorus containing complexing agents is practiced in several countries. The physiological, biochemical and ecological aspects of the microbial degradation of the complexing agents most frequently used, such as polyphosphates, aminopolycarboxylates (especially of nitrilotriacetic acid), and phosphonates are reviewed.

  7. Determination of polymer electrolyte membrane (PEM) degradation products in fuel cell water using electrospray ionization tandem mass spectrometry.

    PubMed

    Zedda, Marco; Tuerk, Jochen; Peil, Stefan; Schmidt, Torsten C

    2010-12-30

    Within the scope of research of membrane degradation phenomena during fuel cell operation a reliable analytical procedure for the extraction, detection and quantification of possible membrane oxidation products has been developed. These oxidation products originate from the attack of hydroxyl or peroxyl radicals on the membrane polymer. Such radicals are formed in situ (during fuel cell operation) or ex situ (Fenton test as oxidative stress simulation). The analysis of membrane oxidation products was carried out by electrospray ionization tandem mass spectrometry. Five potential membrane oxidation products (4-hydroxybenzoic acid (4-HBA), 4-hydroxybenzaldehyde (4-HBAD), 4,4-biphenol (4,4-BP), 4-hydroxybenzenesulfonate (4-HBS), and 4,4-sulfonylbiphenol (4,4-SBP)) were selected based on the molecular structure of the sulfonated polyarylether membrane used. In conjunction with the development of a multiple reaction monitoring (MRM) method, the ionization and fragmentation of the selected compounds were investigated. For 4,4-BP a molecular ion (M(+•) ) was observed in the positive ionization mode and used for MRM method development. Reproducible extraction of the model compounds was achieved using a mixed-mode sorbent material with both weak anion-exchange and reversed-phase retention properties. By using the developed analytical procedure, the identities of two membrane degradation products (4-HBA and 4-HBAD) were determined in situ and ex situ. In addition to the investigation of membrane degradation phenomena, the combination of extraction on a mixed-mode sorbent material and tandem mass spectrometric detection is attractive for the analysis of aromatic sulfonic acids, phenolic acids and phenols.

  8. Herbicides and herbicide degradation products in upper midwest agricultural streams during august base-flow conditions

    USGS Publications Warehouse

    Kalkhoff, S.J.; Lee, K.E.; Porter, S.D.; Terrio, P.J.; Thurman, E.M.

    2003-01-01

    Herbicide concentrations in streams of the U.S. Midwest have been shown to decrease through the growing season due to a variety of chemical and physical factors. The occurrence of herbicide degradation products at the end of the growing season is not well known. This study was conducted to document the occurrence of commonly used herbicides and their degradation products in Illinois, Iowa, and Minnesota streams during base-flow conditions in August 1997. Atrazine, the most frequently detected herbicide (94%), was present at relatively low concentrations (median 0.17 μg L−1). Metolachlor was detected in 59% and cyanazine in 37% of the samples. Seven of nine compounds detected in more than 50% of the samples were degradation products. The total concentration of the degradation products (median of 4.4 μg L−1) was significantly greater than the total concentration of parent compounds (median of 0.26 μg L−1). Atrazine compounds were present less frequently and in significantly smaller concentrations in streams draining watersheds with soils developed on less permeable tills than in watersheds with soils developed on more permeable loess. The detection and concentration of triazine compounds was negatively correlated with antecedent rainfall (April–July). In contrast, acetanalide compounds were positively correlated with antecedant rainfall in late spring and early summer that may transport the acetanalide degradates into ground water and subsequently into nearby streams. The distribution of atrazine degradation products suggests regional differences in atrazine degradation processes.

  9. In vitro degradation and in vivo biocompatibility of poly(lactic acid) mesh for soft tissue reinforcement in vaginal surgery.

    PubMed

    de Tayrac, Renaud; Chentouf, Samir; Garreau, Henri; Braud, Christian; Guiraud, Isabelle; Boudeville, Philippe; Vert, Michel

    2008-05-01

    This study was aimed at evaluating the in vitro degradation, the in vivo biocompatibility and at comparing the effects of two methods of sterilization on poly(L-lactic acid) (PLA(94)) resorbable mesh. The mesh was manufactured to be used as surgical soft tissue reinforcement in the vaginal area. Samples of 100 mg of PLA(94) mesh (10 x 10 mm(2)) were immersed in isoosmolar 0.13M, pH 7.4 phosphate buffer solution at 37 degrees C, during 12 months. The hydrolytic degradation up to 12 months after immersion was monitored by measuring weight loss, mesh area changes, and by various analytical techniques namely Differential scanning calorimetry (DSC), capillary zone electrophoresis (CZE), size exclusion chromatography (SEC), and environmental scanning electron microscopy (ESEM). Specimens of nonsterilized, ethylene-oxide (ETO) sterilized, and gamma-ray sterilized PLA(94) mesh were compared. Fifteen samples were implanted in an incisional hernia Wistar rat model. Histopathology was performed up to 90 days after implantation to evaluate the inflammatory response and the collagen deposition. Although the decrease of molecular weight due to polymer chain scissions started 6 weeks after in vitro immersion, water-soluble degradation products and decrease of tensile strength appeared after 8 months only. Analyses showed also that ETO sterilization did not affect the degradation of the PLA(94) mesh. In contrast, gamma-ray sterilization increased very much the sensitivity of the mesh to the hydrolytic degradation. In vivo, the PLA(94) mesh exhibited good biocompatibility over the investigated time period. PMID:18161812

  10. Photodegradation of fluorene in aqueous solution: Identification and biological activity testing of degradation products.

    PubMed

    Kinani, Said; Souissi, Yasmine; Kinani, Aziz; Vujović, Svetlana; Aït-Aïssa, Sélim; Bouchonnet, Stéphane

    2016-04-15

    Degradation of fluorene under UV-vis irradiation in water was investigated and structural elucidation of the main photoproducts was achieved using gas chromatography coupled with mass spectrometry. Twenty-six photoproducts were structurally identified, mainly on the basis of electron ionization mass spectra interpretation. The main generated transformation products are hydroxy derivatives. Some secondary photoproducts including fluorenone, hydroxy fluorenone, 2-biphenyl carboxylic acid, biphenylene, methanol fluorene congeners and hydroxy fluorene dimers were also observed. A photodegradation pathway was suggested on the basis of the chemical structures of photoproducts. Fluorene as well as its main photoproducts for which chemical standards were commercially available were tested for their ability to elicit cytotoxic, estrogenic and dioxin-like activity by using in vitro cell-based bioassays. None of the tested compounds was cytotoxic at concentrations up to 100 μM. However, 2-hydroxyfluorene and 3-hydroxyfluorene exerted significant estrogenic and dioxin-like activity on a concentration range of 3-30 μM, while fluorene and 9-hydroxyfluorene were weakly or not active, respectively, in our assays. This supports the view that photodegradation processes can generate by-products of higher toxicological concern than the parent compound and strengthens the need to further identify transformation products in the aquatic environment.

  11. Effect of the electric field frequency on ascorbic acid degradation during thermal treatment by ohmic heating.

    PubMed

    Mercali, Giovana Domeneghini; Schwartz, Steven; Marczak, Ligia Damasceno Ferreira; Tessaro, Isabel Cristina; Sastry, Sudhir

    2014-06-25

    In this work, the influence of the electric field frequency and solids content on the degradation kinetics of ascorbic acid during ohmic heating of acerola pulp and acerola serum was investigated. The degradation percentage of ascorbic acid in the pulp after 120 min of heating varied between 12 and 17%. For the serum, the degradation percentage was in the range of 13 and 18%. The results were fitted to the first-order model, and the kinetic rate constants ranged from 1.1 to 1.6×10(-3) min(-1) and from 1.1 to 1.5×10(-3) min(-1) for pulp and serum, respectively. D values ranged between 1480 and 2145 min for the pulp and between 1524 and 1951 min for the serum. A distinct behavior between the kinetic parameters of the pulp and serum in electric field frequencies ranging from 10 to 1000 Hz indicates that the presence of distinct amounts and types of solids might affect the rate of the electron transfer in electrochemical reactions. These variables may also affect the polarization process stimulated by the oscillating electric field. The non-achievement of the equilibrium of the polarization process may have an influence on oxidation reactions, affecting the predisposition to hydrogen donation from the ascorbic acid molecule.

  12. Effect of the Electric Field Frequency on Ascorbic Acid Degradation during Thermal Treatment by Ohmic Heating

    PubMed Central

    Mercali, Giovana Domeneghini; Schwartz, Steven; Marczak, Ligia Damasceno Ferreira; Tessaro, Isabel Cristina; Sastry, Sudhir

    2014-01-01

    In this work, the influence of the electric field frequency and solids content on the degradation kinetics of ascorbic acid during ohmic heating of acerola pulp and acerola serum was investigated. The degradation percentage of ascorbic acid in the pulp after 120 min of heating varied between 12 and 17%. For the serum, the degradation percentage was in the range of 13 and 18%. The results were fitted to the first-order model, and the kinetic rate constants ranged from 1.1 to 1.6 × 10−3 min−1 and from 1.1 to 1.5 × 10−3 min−1 for pulp and serum, respectively. D values ranged between 1480 and 2145 min for the pulp and between 1524 and 1951 min for the serum. A distinct behavior between the kinetic parameters of the pulp and serum in electric field frequencies ranging from 10 to 1000 Hz indicates that the presence of distinct amounts and types of solids might affect the rate of the electron transfer in electrochemical reactions. These variables may also affect the polarization process stimulated by the oscillating electric field. The non-achievement of the equilibrium of the polarization process may have an influence on oxidation reactions, affecting the predisposition to hydrogen donation from the ascorbic acid molecule. PMID:24892902

  13. Hydrothermal synthesis spherical TiO2 and its photo-degradation property on salicylic acid

    NASA Astrophysics Data System (ADS)

    Guo, Wenlu; Liu, Xiaolin; Huo, Pengwei; Gao, Xun; Wu, Di; Lu, Ziyang; Yan, Yongsheng

    2012-07-01

    Anatase TiO2 spheres have been prepared using hydrothermal synthesis. The prepared spheres were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and UV-vis diffuse reflectance spectra (UV-vis DRS). The TiO2 consisted of well-defined spheres with size of 3-5 μm. The photocatalytic activity of spherical TiO2 was determined by degradation of salicylic acid under visible light irradiation. It was revealed that the degradation rate of the spherical TiO2 which was processed at 150 °C for 48 h could reach 81.758%. And the kinetics of photocatalytic degradation obeyed first-order kinetic, which the rate constant value was 0.01716 S-1 of the salicylic acid onto TiO2 (temperature: 150, time: 48 h). The kinetics of adsorption followed the pseudo-second-order model and the rate constant was 1.2695 g mg-1 of the salicylic acid onto TiO2 (temperature: 150, time: 48 h).

  14. Optimized photocatalytic degradation of caffeic acid by sol-gel TiO₂.

    PubMed

    García-Montelongo, Xiomara L; Martínez-de la Cruz, Azael; Contreras, David; Mansilla, Héctor D

    2015-01-01

    TiO₂anatase powder was prepared by means of the sol-gel method with titanium(IV) butoxide as precursor. The formation of a tetragonal crystal structure of TiO₂anatase at 500 °C was confirmed by X-ray powder diffraction. The characterization of the samples synthesized was complemented by scanning electron microscopy, diffuse reflectance infrared Fourier transform spectroscopy, nitrogen adsorption-desorption isotherms (Brunauer-Emmett-Teller) and diffuse reflectance spectroscopy. The photocatalytic activity of the TiO₂anatase powder was evaluated in the degradation of caffeic acid in aqueous solution under ultraviolet radiation. A central composite circumscribed design was used to assess the weight of the experimental variables, pH and amount of catalyst in the percentage of caffeic acid degraded and the optimal conditions. The optimized conditions were found to be pH = 5.2 and a load of TiO₂of 1.1 g L⁻¹. Under these conditions more than 90% of caffeic acid degradation was achieved after 30 min of lamp irradiation. At this time the mineralization reached was almost 60%.

  15. The Degradation of 14C-Glutamic Acid by L-Glutamic Acid Decarboxylase.

    ERIC Educational Resources Information Center

    Dougherty, Charles M; Dayan, Jean

    1982-01-01

    Describes procedures and semi-micro reaction apparatus (carbon dioxide trap) to demonstrate how a particular enzyme (L-Glutamic acid decarboxylase) may be used to determine the site or sites of labeling in its substrate (carbon-14 labeled glutamic acid). Includes calculations, solutions, and reagents used. (Author/SK)

  16. Polylactide stereocomplexation leads to higher hydrolytic stability but more acidic hydrolysis product pattern.

    PubMed

    Andersson, Sofia Regnell; Hakkarainen, Minna; Inkinen, Saara; Södergård, Anders; Albertsson, Ann-Christine

    2010-04-12

    Poly-l-lactide/poly-d-lactide (PLLA/PDLA) stereocomplex had much higher hydrolytic stability compared to plain PLLA, but at the same time shorter and more acidic degradation products were formed. Both materials were subjected to hydrolytic degradation in water and in phosphate buffer at 37 and 60 degrees C, and the degradation processes were monitored by following mass loss, water uptake, thermal properties, surface changes, and pH of the aging medium. The degradation product patterns were determined by electrospray ionization-mass spectrometry (ESI-MS). The high crystallinity and strong secondary interactions in the stereocomplex prevented water uptake and resulted in lower mass loss and degradation rate. However, somewhat surprisingly, the pH of the aging medium decreased much faster in the case of PLLA/PDLA stereocomplex. In accordance, the ESI-MS results showed that hydrolysis of PLLA/PDLA resulted in shorter and more acidic degradation products. This could be explained by the increased intermolecular crystallization due to stereocomplexation, which results in an increased number of tie chains. Because mainly these short tie chains are susceptible to hydrolysis this leads to formation of shorter oligomers compared to hydrolysis of regular PLLA.

  17. Modeling of olive oil degradation and oleic acid inhibition during chemostat and batch cultivation of Bacillus thermoleovorans IHI-91.

    PubMed

    Becker, P; Märkl, H

    2000-12-20

    Olive oil degradation by the thermophilic lipolytic strain Bacillus thermoleovorans IHI-91 in chemostat and batch culture was modeled to obtain a general understanding of the underlying principles and limitations of the process and to quantify its stoichiometry. Chemostat experiments with olive oil as the sole carbon source were successfully described using the Monod chemostat model extended by terms for maintenance requirements and wall growth. Maintenance requirements and biomass yield coefficients were in the range reported for mesophiles. For a chemostat experiment at D = 0.3 h(-1) the model was validated up to an olive oil feed concentration of about 3.0 g L(-1) above which an inhibitory effect occurred. Further analysis showed that the liberated oleic acid is the main cause for this inhibition. Using steady-state oleic acid concentrations measured in chemostat experiments with olive oil as substrate it was possible to derive a kinetic expression for oleic acid utilization, showing that a concentration of 430 mg L(-1) leads to a complete growth inhibition. Oleic acid accumulation observed during batch fermentations can be predicted using a model involving growth-associated lipase production and olive oil hydrolysis. Simulations confirmed that this accumulation is the cause for the sudden growth cessation occurring in batch fermentations with higher olive oil start concentrations. Further, an oscillatory behavior, as observed in some chemostat experiments, can also be predicted using the latter model. This work clearly demonstrates that thermophilic lipid degradation by Bacillus thermoleovorans IHI-91 is limited by long-chain fatty acid beta-oxidation rather than oil hydrolysis.

  18. Identification and characterization of stress degradation products of dronedarone hydrochloride employing LC-UV/PDA, LC-MS/TOF and MS(n) studies.

    PubMed

    Chadha, Renu; Bali, Alka; Bansal, Gulshan

    2016-01-25

    Dronedarone HCl was subjected to forced decomposition conditions of hydrolysis (neutral, acidic and alkaline), oxidation, photolysis and thermal stress, as suggested in the ICH guideline Q1A(R2). The drug showed significant degradation under alkaline hydrolytic and alkaline photolytic conditions while it remained stable in neutral, acidic, thermal and oxidative conditions. In total, six degradation products (I-VI) were formed, which could be separated by chromatography on C18 (250 mm × 4.6 mm; 5 μ, Xterra) column using isocratic elution method. Detection wavelength was selected as 288 nm. Multi-stage (MS(n)) and MS/TOF accurate mass studies were carried out to establish the complete fragmentation pathway of the drug which in turn was utilized in characterization of the products. The degradation pathway of the drug leading to generation of products I-VI was postulated and this has not been reported so far. PMID:26547261

  19. Monitoring the dynamics of syntrophic β-oxidizing bacteria during anaerobic degradation of oleic acid by quantitative PCR.

    PubMed

    Ziels, Ryan M; Beck, David A C; Martí, Magalí; Gough, Heidi L; Stensel, H David; Svensson, Bo H

    2015-04-01

    The ecophysiology of long-chain fatty acid-degrading syntrophic β-oxidizing bacteria has been poorly understood due to a lack of quantitative abundance data. Here, TaqMan quantitative PCR (qPCR) assays targeting the 16S rRNA gene of the known mesophilic syntrophic β-oxidizing bacterial genera Syntrophomonas and Syntrophus were developed and validated. Microbial community dynamics were followed using qPCR and Illumina-based high-throughput amplicon sequencing in triplicate methanogenic bioreactors subjected to five consecutive batch feedings of oleic acid. With repeated oleic acid feeding, the initial specific methane production rate significantly increased along with the relative abundances of Syntrophomonas and methanogenic archaea in the bioreactor communities. The novel qPCR assays showed that Syntrophomonas increased from 7 to 31% of the bacterial community 16S rRNA gene concentration, whereas that of Syntrophus decreased from 0.02 to less than 0.005%. High-throughput amplicon sequencing also revealed that Syntrophomonas became the dominant genus within the bioreactor microbiomes. These results suggest that increased specific mineralization rates of oleic acid were attributed to quantitative shifts within the microbial communities toward higher abundances of syntrophic β-oxidizing bacteria and methanogenic archaea. The novel qPCR assays targeting syntrophic β-oxidizing bacteria may thus serve as monitoring tools to indicate the fatty acid β-oxidization potential of anaerobic digester communities.

  20. Low environmentally relevant levels of bioactive xenobiotics and associated degradation products cause cryptic perturbations of metabolism and molecular stress responses in Arabidopsis thaliana.

    PubMed

    Serra, Anne-Antonella; Nuttens, Andréïna; Larvor, Vanessa; Renault, David; Couée, Ivan; Sulmon, Cécile; Gouesbet, Gwenola

    2013-07-01

    Anthropic changes and chemical pollution confront wild plant communities with xenobiotic combinations of bioactive molecules, degradation products, and adjuvants that constitute chemical challenges potentially affecting plant growth and fitness. Such complex challenges involving residual contamination and mixtures of pollutants are difficult to assess. The model plant Arabidopsis thaliana was confronted by combinations consisting of the herbicide glyphosate, the fungicide tebuconazole, the glyphosate degradation product aminomethylphosphonic acid (AMPA), and the atrazine degradation product hydroxyatrazine, which had been detected and quantified in soils of field margins in an agriculturally intensive region. Integrative analysis of physiological, metabolic, and gene expression responses was carried out in dose-response experiments and in comparative experiments of varying pesticide combinations. Field margin contamination levels had significant effects on plant growth and metabolism despite low levels of individual components and the presence of pesticide degradation products. Biochemical and molecular analysis demonstrated that these less toxic degradation products, AMPA and hydroxyatrazine, by themselves elicited significant plant responses, thus indicating underlying mechanisms of perception and transduction into metabolic and gene expression changes. These mechanisms may explain observed interactions, whether positive or negative, between the effects of pesticide products (AMPA and hydroxyatrazine) and the effects of bioactive xenobiotics (glyphosate and tebuconazole). Finally, the metabolic and molecular perturbations induced by low levels of xenobiotics and associated degradation products were shown to affect processes (carbon balance, hormone balance, antioxidant defence, and detoxification) that are likely to determine environmental stress sensitivity.

  1. The behavior of tetracyclines and their degradation products during swine manure composting.

    PubMed

    Wu, Xiaofeng; Wei, Yuansong; Zheng, Jiaxi; Zhao, Xin; Zhong, Weike

    2011-05-01

    The purposes of this study were to investigate the behavior of three tetracyclines including chlortetracycline (CTC), oxytetracycline (OTC) and tetracycline (TC) and their degradation products in a pilot scale swine manure composting, and also to study the degradation kinetics of CTC, OTC and TC. During the pilot scale composting, CTC, OTC and TC were degraded by 74%, 92% and 70%, respectively. Several degradation products were found like 4-epitetracycline (ETC), 4-epioxytetracycline (EOTC), 4-epichlortetracycline (ECTC), demeclocycline (DMCTC) and anhydrotetracycline (ATC). Both the simple and the adjusted first-order kinetic models successfully fit the degradation process of CTC, OTC and TC during the composting, but the adjusted first-order kinetic model fit much better with the calculated half-lives of 8.2, 1.1 and 10.0 days, respectively.

  2. Toxicity and physical properties of atrazine and its degradation products: A literature survey

    SciTech Connect

    Pugh, K.C.

    1994-10-01

    The Tennessee Valley Authority`s Environmental Research Center has been developing a means of detoxifying atrazine waste waters using TiO{sub 2} photocatalysis. The toxicity and physical properties of atrazine and its degradation products will probably be required information in obtaining permits from the United States Environmental Protection Agency for the demonstration of any photocatalytic treatment of atrazine waste waters. The following report is a literature survey of the toxicological and physical properties of atrazine and its degradation products.

  3. Isolation and characterization of a novel acid degradation impurity of Amlodipine Besylate using Q-TOF, NMR, IR and single crystal X-ray.

    PubMed

    Rapolu, Ravi; Raju, Ch Krishnam; Srinivas, Kolupula; Awasthi, Atul; Navalgund, Sameer G; Surendranath, Koduru V

    2014-10-01

    Forced degradation of Amlodipine Besylate (AMD) in acidic condition gave rise to a potential unknown impurity. This unknown acid degradation product (ADP) was evaluated using a new-reverse-phase high performance liquid chromatography (HPLC), where it was eluted at 1.24 relative retention time to AMD peak. ADP was isolated using preparative HPLC from degradation mixture. Later, structure of ADP was elucidated using high resolution MS, multidimensional NMR and FTIR spectroscopic techniques, and characterized as ethyl-6-(2-chlorophenyl)-8-methyl-3,4,6,7-tetrahydro-2H-benzo[b][1,4]oxazine-5-carboxylate. The presence of ADP recemic mixture was confirmed by polarimeter and chiral HPLC. Given the complexity associated with ADP generation, single crystal X-ray crystallography technique was used to confirm proposed structure. In addition, reaction mechanism was postulated and confirmed using computational chemistry. To our knowledge, it is a novel impurity and not reported elsewhere. PMID:25072842

  4. Impact of folic acid supplementation on single- and double-stranded RNA degradation in human colostrum and mature milk.

    PubMed

    Kocic, Gordana; Bjelakovic, Ljiljana; Bjelakovic, Bojko; Jevtoci-Stoimenov, Tatjana; Sokolovic, Dusan; Cvetkovic, Tatjana; Kocic, Hristina; Stojanovic, Svetlana; Langerholc, Tomaz; Jonovic, Marina

    2014-07-01

    Sufficient intake of folic acid is necessary for normal embryogenesis, fetal, and neonatal development. Folic acid facilitates nucleic acid internalization, and protects cellular DNA from nuclease degradation. Human milk contains enzymes, antimicrobial proteins, and antibodies, along with macrophages, that protect against infections and allergies. However, little to no information is available on the effects of folic acid supplementation on degradation of nucleic acids in human milk. In the present study, we aimed to determine the RNase activity (free and inhibitor-bound) in colostrum and mature milk, following folic acid supplementation. The study design included a total of 59 women, 27 of whom received 400 μg of folic acid daily periconceptionally and after. Folic acid supplementation increased the free RNase and polyadenylase activity following lactation. However, the increased RNase activity was not due to de novo enzyme synthesis, as the inhibitor-bound (latent) RNase activity was significantly lower and disappeared after one month. Folic acid reduced RNase activity by using double-stranded RNA as substrate. Data suggests that folic acid supplementation may improve viral RNAs degradation and mRNA degradation, but not dsRNA degradation, preserving in this way the antiviral defense.

  5. Production of Succinic Acid from Citric Acid and Related Acids by Lactobacillus Strains

    PubMed Central

    Kaneuchi, Choji; Seki, Masako; Komagata, Kazuo

    1988-01-01

    A number of Lactobacillus strains produced succinic acid in de Man-Rogosa-Sharpe broth to various extents. Among 86 fresh isolates from fermented cane molasses in Thailand, 30 strains (35%) produced succinic acid; namely, 23 of 39 Lactobacillus reuteri strains, 6 of 18 L. cellobiosus strains, and 1 of 6 unidentified strains. All of 10 L. casei subsp. casei strains, 5 L. casei subsp. rhamnosus strains, 6 L. mali strains, and 2 L. buchneri strains did not produce succinic acid. Among 58 known strains including 48 type strains of different Lactobacillus species, the strains of L. acidophilus, L. crispatus, L. jensenii, and L. parvus produced succinic acid to the same extent as the most active fresh isolates, and those of L. alimentarius, L. collinoides, L. farciminis, L. fructivorans (1 of 2 strains tested), L. malefermentans, and L. reuteri were also positive, to lesser extents. Diammonium citrate in de Man-Rogosa-Sharpe broth was determined as a precursor of the succinic acid produced. Production rates were about 70% on a molar basis with two fresh strains tested. Succinic acid was also produced from fumaric and malic acids but not from dl-isocitric, α-ketoglutaric, and pyruvic acids. The present study is considered to provide the first evidence on the production of succinic acid, an important flavoring substance in dairy products and fermented beverages, from citrate by lactobacilli. PMID:16347795

  6. The production and testing of staphylococci with clumping factor activity for use in the assay of fibrinogen degradation products

    PubMed Central

    Richardson, G.

    1973-01-01

    A method for the large-scale production of a staphylococcal preparation for use in the assay of fibrinogen degradation products is described. The material is assayed against a fibrinogen standard and is shown to be stable over long periods and of high sensitivity. The possibility of production on an occasional basis in a routine laboratory is discussed. PMID:4577031

  7. Regulation of the Pseudomonas sp. Strain ADP Cyanuric Acid Degradation Operon

    PubMed Central

    García-González, Vicente; Govantes, Fernando; Porrúa, Odil; Santero, Eduardo

    2005-01-01

    Pseudomonas sp. strain ADP is the model strain for studying bacterial degradation of the s-triazine herbicide atrazine. In this work, we focused on the expression of the atzDEF operon, involved in mineralization of the central intermediate of the pathway, cyanuric acid. Expression analysis of atzD-lacZ fusions in Pseudomonas sp. strain ADP and Pseudomonas putida showed that atzDEF is subjected to dual regulation in response to nitrogen limitation and cyanuric acid. The gene adjacent to atzD, orf99 (renamed here atzR), encoding a LysR-like regulator, was found to be required for both responses. Expression of atzR-lacZ was induced by nitrogen limitation and repressed by AtzR. Nitrogen regulation of atzD-lacZ and atzR-lacZ expression was dependent on the alternative σ factor σN and NtrC, suggesting that the cyanuric acid degradation operon may be subject to general nitrogen control. However, while atzR is transcribed from a σN-dependent promoter, atzDEF transcription appears to be driven from a σ70-type promoter. Expression of atzR from a heterologous promoter revealed that although NtrC regulation of atzD-lacZ requires the AtzR protein, it is not the indirect result of NtrC-activated AtzR synthesis. We propose that expression of the cyanuric acid degradation operon atzDEF is controlled by means of a complex regulatory circuit in which AtzR is the main activator. AtzR activity is in turn modulated by the presence of cyanuric acid and by a nitrogen limitation signal transduced by the Ntr system. PMID:15601699

  8. Characterization of forced degradation products of ketorolac tromethamine using LC/ESI/Q/TOF/MS/MS and in silico toxicity prediction.

    PubMed

    Kalariya, Pradipbhai D; Raju, B; Borkar, Roshan M; Namdev, Deepak; Gananadhamu, S; Nandekar, Prajwal P; Sangamwar, Abhay T; Srinivas, R

    2014-05-01

    Ketorolac, a nonsteroidal anti-inflammatory drug, was subjected to forced degradation studies as per International Conference on Harmonization guidelines. A simple, rapid, precise, and accurate high-performance liquid chromatography combined with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (LC/ESI/Q/TOF/MS/MS) method has been developed for the identification and structural characterization of stressed degradation products of ketorolac. The drug was found to degrade in hydrolytic (acidic, basic, and neutral), photolytic (acidic, basic, and neutral solution), and thermal conditions, whereas the solid form of the drug was found to be stable under photolytic conditions. The method has shown adequate separation of ketorolac tromethamine and its degradation products on a Grace Smart C-18 (250 mm × 4.6 mm i.d., 5 µm) column using 20 mM ammonium formate (pH = 3.2): acetonitrile as a mobile phase in gradient elution mode at a flow rate of 1.0 ml/min. A total of nine degradation products were identified and characterized by LC/ESI/MS/MS. The most probable mechanisms for the formation of degradation products have been proposed on the basis of a comparison of the fragmentation of the [M + H](+) ions of ketorolac and its degradation products. In silico toxicity of the drug and degradation products was investigated by using topkat and derek softwares. The method was validated in terms of specificity, linearity, accuracy, precision, and robustness as per International Conference on Harmonization guidelines.

  9. Oxidative degradation of bis (2,4,4-trimethylpentyl) dithiophosphinic acid in nitric acid studied by electrospray ionization mass spectrometry

    SciTech Connect

    G. S. Groenewold; D. R. Peterman

    2012-10-01

    Samples of bis(2,4,4-trimethylpentyl)dithiophosphinic