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Sample records for acid sulfites

  1. Reductive defluorination of perfluorooctanoic acid by hydrated electrons in a sulfite-mediated UV photochemical system

    Song, Zhou [Key Laboratory of Catalysis and Materials Science of the State Ethnic Affairs Commission and Ministry of Education, College of Chemistry and Materials Science, South-Central University for Nationalities, Wuhan 430074 (China); College of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Tang, Heqing, E-mail: tangheqing@mail.scuec.edu.cn [Key Laboratory of Catalysis and Materials Science of the State Ethnic Affairs Commission and Ministry of Education, College of Chemistry and Materials Science, South-Central University for Nationalities, Wuhan 430074 (China); Wang, Nan, E-mail: nwang83@sina.com [College of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Zhu, Lihua [College of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2013-11-15

    Highlights: • A new reductive method for PFOA defluorination was established by sulfite-mediated photolysis. • The defluorination of PFOA was dependent on sulfite concentration and solution pH. • A defluorination ratio of PFOA as high as 88.5% was achieved after reaction of 24 h. • A few of perfluorinated sulfonates were detected as intermediates during the degradation of PFOA. • A mechanism was proposed for the reductive defluorination of PFOA by hydrated electrons. -- Abstract: A method for reductive degradation of perfluorooctanoic acid (PFOA) was established by using a sulfite/UV process. This process led to a PFOA removal of 100% at about 1 h and a defluorination ratio of 88.5% at reaction time of 24 h under N{sub 2} atmosphere, whereas the use of either UV irradiation or SO{sub 3}{sup 2−} alone induced little defluorination of PFOA under the same conditions. It was confirmed that the reductive defluorination of PFOA was achieved by hydrated electrons being generated from the photo-conversion of SO{sub 3}{sup 2−} as a mediator. Theoretical reaction kinetic analysis demonstrated that the generation of hydrated electrons was promoted by increasing either SO{sub 3}{sup 2−} concentration or solution pH, leading to the acceleration of the PFOA defluorination. Accompanying the reduction of PFOA, a small amount of short-chain perfluorocarboxylic acids, less fluorinated carboxylic acids and perfluorinated alkyl sulfonates were generated, all of which were able to be further degraded with further releasing of fluoride ions. Based on the generation, accumulation and distribution of intermediates, hydrated electrons induced defluorination pathway of PFOA was proposed in a sulfite-mediated UV photochemical system.

  2. Reductive defluorination of perfluorooctanoic acid by hydrated electrons in a sulfite-mediated UV photochemical system

    Highlights: • A new reductive method for PFOA defluorination was established by sulfite-mediated photolysis. • The defluorination of PFOA was dependent on sulfite concentration and solution pH. • A defluorination ratio of PFOA as high as 88.5% was achieved after reaction of 24 h. • A few of perfluorinated sulfonates were detected as intermediates during the degradation of PFOA. • A mechanism was proposed for the reductive defluorination of PFOA by hydrated electrons. -- Abstract: A method for reductive degradation of perfluorooctanoic acid (PFOA) was established by using a sulfite/UV process. This process led to a PFOA removal of 100% at about 1 h and a defluorination ratio of 88.5% at reaction time of 24 h under N2 atmosphere, whereas the use of either UV irradiation or SO32− alone induced little defluorination of PFOA under the same conditions. It was confirmed that the reductive defluorination of PFOA was achieved by hydrated electrons being generated from the photo-conversion of SO32− as a mediator. Theoretical reaction kinetic analysis demonstrated that the generation of hydrated electrons was promoted by increasing either SO32− concentration or solution pH, leading to the acceleration of the PFOA defluorination. Accompanying the reduction of PFOA, a small amount of short-chain perfluorocarboxylic acids, less fluorinated carboxylic acids and perfluorinated alkyl sulfonates were generated, all of which were able to be further degraded with further releasing of fluoride ions. Based on the generation, accumulation and distribution of intermediates, hydrated electrons induced defluorination pathway of PFOA was proposed in a sulfite-mediated UV photochemical system

  3. Intrinsic oxidation kinetics of sulfite catalyzed by peracetic acid under different water quality and light conditions

    2009-01-01

    Oxidation of sulfite is an important process in wet flue gas desulfurization.Using highly purified water or distilled water as a reaction medium and a transparent or an opaque intermittent reaction apparatus,the intrinsic oxidation kinetics of sulfite catalyzed by peracetic acid was investigated under four dif-ferent conditions.The reaction order of the reagents and the activation energy were obtained.The re-sults indicate that water quality and light have no obvious effects on the reaction order and activation energy,but have an influence on the reaction rate constant.The mechanism of the intrinsic reaction is proposed.The results derived with this mechanism are in good agreement with the experimental re-sults.

  4. Utilisation of sulfites by animals

    It studied the uptake of radioactive sulfates and sulfites in sulfinic cysteine acid, taurine and cystine in animal organism. The experiments are conducted on rabbits. The experimental procedures are described: one experiment is to sterilize intestines of the animal before to inject it radioactive sulfites or sulfates, the rabbit is sacrificed 28 hours after and its organs analysed. The other experiment is to inject radioactive sulfites or sulfates in an eviscerated rabbit and sacrificed it 30 minutes after. Sulfinic cysteine acid is mainly found in liver extracts after 30 minutes and only after injection of radioactive sulfites, whereas cystine is found after 28 hours in a majority of organ extracts. It showed that sulfur used for the synthesis of sulfinic cysteine acid comes from sulfites intake and that sulfinic cysteine acid is a precursor of taurine and cystine. (M.P.)

  5. Optimization of Sulfide/Sulfite Pretreatment of Lignocellulosic Biomass for Lactic Acid Production

    Muhammad Idrees

    2013-01-01

    Full Text Available Potential of sodium sulfide and sodium sulfite, in the presence of sodium hydroxide was investigated to pretreat the corncob (CC, bagasse (BG, water hyacinth and rice husk (RH for maximum digestibility. Response Surface Methodology was employed for the optimization of pretreatment factors such as temperature, time and concentration of Na2S and Na2SO3, which had high coefficient of determination (R2 along with low probability value (P, indicating the reliable predictability of the model. At optimized conditions, Na2S and Na2SO3 remove up to 97% lignin, from WH and RH, along with removal of hemicellulose (up to 93% during pretreatment providing maximum cellulose, while in BG and CC; 75.0% and 90.0% reduction in lignin and hemicellulose was observed. Saccharification efficiency of RH, WH, BG and CC after treatment with 1.0% Na2S at 130°C for 2.3–3.0 h was 79.40, 85.93, 87.70, and 88.43%, respectively. WH treated with Na2SO3 showed higher hydrolysis yield (86.34% as compared to Na2S while other biomass substrates showed 2.0–3.0% less yield with Na2SO3. Resulting sugars were evaluated as substrate for lactic acid production, yielding 26.48, 25.36, 31.73, and 30.31 gL−1 of lactic acid with 76.0, 76.0, 86.0, and 83.0% conversion yield from CC, BG, WH, and RH hydrolyzate, respectively.

  6. Comparison of Condensation Reactions of Lignin at Cα-Positionsin Kraft and Acid Sulfite Delignification of Western Hemlock

    Funaoka, Masamitsu; Chiang, Vincent L.; Kolppo, Kari; Stokke, Douglas D.; 船岡, 正光

    1991-01-01

    Acid sulfite delignification of western hemlock(Tsuga heterophylla)was carried out from 90℃ to a final temperature of 145℃. Kraft pulping was also carried out from 90℃,but to a final temperature of 170℃. At various stages of delignification structual units condensed at Cα-positions in residual lignins weredetemined directly without isolating their lignins.In kraft pulping,the formation of structural units condensed at Cα-positions started at the point where about 50% of the lignin were remove...

  7. [Ion chromatography of L-ascorbic acid, sulfite and thiosulfate using their postcolumn reactions with cerium (IV) and fluorescence detection of cerium (III)].

    Chen, Q; Hu, K; Miura, Y

    1999-09-01

    An ion chromatographic method was used to separate the species of L-ascorbic acid, sulfite and thiosulfate in their mixtures. This method is based on the separation of each anion in their mixtures by using a separation column, and then on the fluorimetric measurement of cerium (III) formed by a postcolumn reaction of cerium (IV) with the species of L-ascorbic acid, sulfite and thiosulfate in the effluent. The optimal conditions for separating and determining the above three species have been established. By using a 3 mmol/L carbonate eluent, the species of L-ascorbic acid, sulfite and thiosulfate could be eluted at the proper retention times of 1.7, 2.6 and 5.0 min, respectively, and these three anions could be separated completely. The effects of the concentrations of cerium (IV) and sulfuric acid in the postcolumn reaction solution on the chromatographic peak-height were tested in order to obtain the optimal peak-height. It was found that the peak-height at first increases rapidly with an increase in the concentration of cerium (IV) and sulfuric acid respectively up to a certain concertation, then increases slowly. These critical concentrations of cerium (IV) and sulfuric acid also depend on the amount of the analyte injected. Meanwhile the baseline signals of the sepectra increase with an increase in the concentration of cerium (IV). Some concentrations above the critical concentration of sulfuric acid could be selected as the optimal concentration of sulfuric acid, but the concentration of cerium (IV) should be optimized by establishing a compromise between the higher peak-height and the lower baseline signal. The detection limit of this method was found to be 1 mumol/L for thiosulfate when an amount of 100 microL analyte was injected. PMID:12552889

  8. Electrocatalytic sulfite biosensor with human sulfite oxidase co-immobilized with cytochrome c in a polyelectrolyte-containing multilayer

    Spricigo, Roberto; Dronov, Roman; Lisdat, Fred; Leimkühler, Silke; Frieder W. Scheller; Wollenberger, Ulla

    2008-01-01

    An efficient electrocatalytic biosensor for sulfite detection was developed by co-immobilizing sulfite oxidase and cytochrome c with polyaniline sulfonic acid in a layer-by-layer assembly. QCM, UV–Vis spectroscopy and cyclic voltammetry revealed increasing loading of electrochemically active protein with the formation of multilayers. The sensor operates reagentless at low working potential. A catalytic oxidation current was detected in the presence of sulfite at the modified gold electrode, p...

  9. Use of sulfite and hydrogen peroxide to control bacterial contamination in ethanol fermentation.

    Chang, I S; B.H. Kim; Shin, P K

    1997-01-01

    Lactic acid bacteria isolated from an industrial-scale ethanol fermentation process were used to evaluate sulfite as a bacterial-contamination control agent in a cell-recycled continuous ethanol fermentation process. The viabilities of bacteria were decreased by sulfite at concentrations of 100 to 400 mg liter-1, while sulfite at the same concentrations did not change the viability of the Saccharomyces cerevisiae strain used in this process. Sulfite was effective only in the presence of oxyge...

  10. VOLATILE COMPONENT RECOVERY FROM SULFITE EVAPORATOR CONDENSATE

    This study is on the operation and modification of a demonstration unit to remove sulfur dioxide, methanol, furfural, and acetic acid from its sulfite evaporator condensate. This unit consisted of a steam stripper, vent tank SO2 recovery, activated carbon adsorption columns, and ...

  11. Cadmium sulfite hexahydrate revisited

    Sergio Baggio

    2008-07-01

    Full Text Available The present structural revision of the title compound, tetracadmium tetrasulfite hexahydrate, [Cd4(SO34(H2O5]·H2O, is a low-temperature upgrade (T = 100 K and R = 0.017 of the original room-temperature structure reported by Kiers & Vos [Cryst. Struct. Commun. (1978. 7, 399–403; T = 293 K and R = 0.080. The compound is a three-dimensional polymer with four independent cadmium centres, four sulfite anions and six water molecules, five of them coordinated to two cadmium centres and the remaining one an unbound solvent molecule which completes the asymmetric unit. There are two types of cadmium environment: CdO8 (through four chelating sulfite ligands and CdO6 (by way of six monocoordinated ligands. The former groups form planar arrays [parallel to (001 and separated by half a unit cell translation along c], made up of chains running along [110] and [overline{1}10], respectively. These chains are, in turn, interconnected both in an intraplanar as well as in an interplanar fashion by the latter CdO6 polyhedra into a tight three-dimensional framework. There is, in addition, an extensive network of hydrogen bonds, in which all 12 water H atoms act as donors and eight O atoms from all four sulfite groups and two water molecules act as acceptors.

  12. Cadmium sulfite hexahydrate revisited

    Sergio Baggio; Andrés Ibáñez; Ricardo Baggio

    2008-01-01

    The present structural revision of the title compound, tetracadmium tetrasulfite hexahydrate, [Cd4(SO3)4(H2O)5]·H2O, is a low-temperature upgrade (T = 100 K and R = 0.017) of the original room-temperature structure reported by Kiers & Vos [Cryst. Struct. Commun. (1978). 7, 399–403; T = 293 K and R = 0.080). The compound is a three-dimensional polymer with four independent cadmium centres, four sulfite anions and six water molecules, five of them coordinated to two c...

  13. Evaluation of microbial diversity in sulfite-added and sulfite-free wine by culture-dependent and -independent methods.

    Takahashi, Masayuki; Ohta, Tami; Masaki, Kazuo; Mizuno, Akihiro; Goto-Yamamoto, Nami

    2014-05-01

    The difference in microbiota including non-lactic acid bacteria, non-acetic acid bacteria, and wild yeast during winemaking and in the end-products between sulfite-added and sulfite-free wine, was investigated using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and a culture-dependent method. There were differences between the microorganisms detected by PCR-DGGE and those detected by the culture-dependent method, probably because of the selectivity of culture medium and the characteristics of PCR-based method. In both the red wine and white wine, the microbial diversity of the sulfite-added wine was lower than that of the sulfite-free wine during fermentation. Tatumella terrea was detected from the fermenting must by PCR-DGGE and by the culture-dependent method, even though sulfite inhibited its growth to some extent. We confirmed that the addition of sulfite plays an important role in winemaking by inhibiting the growth of unexpected microorganisms, but on the other hand, it was revealed that some microorganisms can survive and grow in sulfite-added fermenting must. We also analyzed 15 samples of commercial wines by the PCR-DGGE method and detected various microorganisms. Among them, Sphingomonas sp., Pseudozyma sp., Ochromonas sp. and Methylophilus sp. were found for the first time in wine as far as we know. We did not identify a specific microorganism that was detected only from wines without sulfite addition. Thus, the microbiota of end-products seemed to be influenced by other factors, such as filtration before bottling, the production equipment and the storage environment. PMID:24239025

  14. Electrocatalytic sulfite biosensor with human sulfite oxidase co-immobilized with cytochrome c in a polyelectrolyte-containing multilayer.

    Spricigo, Roberto; Dronov, Roman; Lisdat, Fred; Leimkühler, Silke; Scheller, Frieder W; Wollenberger, Ulla

    2009-01-01

    An efficient electrocatalytic biosensor for sulfite detection was developed by co-immobilizing sulfite oxidase and cytochrome c with polyaniline sulfonic acid in a layer-by-layer assembly. QCM, UV-Vis spectroscopy and cyclic voltammetry revealed increasing loading of electrochemically active protein with the formation of multilayers. The sensor operates reagentless at low working potential. A catalytic oxidation current was detected in the presence of sulfite at the modified gold electrode, polarized at +0.1 V (vs. Ag/AgCl 1 M KCl). The stability of the biosensor performance was characterized and optimized. A 17-bilayer electrode has a linear range between 1 and 60 microM sulfite with a sensitivity of 2.19 mA M(-1) sulfite and a response time of 2 min. The electrode retained a stable response for 3 days with a serial reproducibility of 3.8% and lost 20% of sensitivity after 5 days of operation. It is possible to store the sensor in a dry state for more than 2 months. The multilayer electrode was used for determination of sulfite in unspiked and spiked samples of red and white wine. The recovery and the specificity of the signals were evaluated for each sample. PMID:18932024

  15. Improvements in amperometric detection of sulfite in food matrixes.

    Wygant, M B; Statler, J A; Henshall, A

    1997-01-01

    Sulfite is added to foods as an antimicrobial, antibrowning agent, or antioxidant. It also can occur naturally, and is often used in the production of beer and wine. For years the standard methodology for determination of sulfite in foods has been the Monier-Williams method, which is a combination of acid distillation and titration. Recently, AOAC adopted a chromatographic method based on a method developed by Kim and Kim for the determination of sulfite. The method combines ion exclusion chromatography with direct-current (DC) amperometric detection to provide more convenient and accurate quantitation of sulfite. However, fouling of the platinum working electrode results in a rapid decrease in method sensitivity. As a result, standards must be injected before and after every sample, and the electrode must be polished frequently to maintain adequate detection limits. Pulsed amperometric detection overcomes electrode fouling problems by repeatedly and continuously applying cleaning potentials to the working electrode. Using this technique, a reproducible electrode surface can be maintained, and injection-to-injection repeatability is greatly improved. A comparison of method performance for both DC and pulsed amperometric detection is presented. Also investigated was the stability of sulfite samples at varying pH, and in the presence or absence of a preservative. PMID:9419871

  16. Immunological comparison of sulfite oxidase

    Pollock, V.; Barber, M.J. (Univ. South Florida College, Tampa (United States))

    1991-03-11

    Polyclonal antibodies (rabbit), elicited against FPLC-purified chicken and rat liver sulfite oxidase (SO), have been examined for inhibition and binding to purified chicken (C), rat (R), bovine (B), alligator (A) and shark (S) liver enzymes. Anti-CSO IgG cross-reacted with all five enzymes, with varying affinities, in the order CSO=ASO{gt}RSO{gt}BSO{gt}SSO. Anti-ROS IgG also cross-reacted with all five enzymes in the order RSO{gt}CSO=ASO{gt}BSO{gt}SSO. Anti-CSO IgG inhibited sulfite:cyt. c reductase (S:CR), sulfite:ferricyanide reductase (S:FR) and sulfite:dichlorophenolindophenol reductase (S:DR) activities of CSO to different extents (S:CR{gt}S:FR=S:DR). Similar differential inhibition was found for anti-ROS IgG and RSO S:CR, S:FR and S:DR activities. Anti-CSO IgG inhibited S:CR activities in the order CSO=ASO{much gt}SSO{gt}BSO. RSO was uninhibited. For anti-RSO IgG the inhibition order was RSO{gt}SSO{gt}BSO{gt}ASO. CSO was uninhibited. Anti-CSO and RSO IgGs partially inhibited Chlorella nitrate reductase (NR). Minor cross-reactivity was found for xanthine oxidase. Common antigenic determinants for all five SO's and NR are indicated.

  17. Techno-economics of integrating bioethanol production from spent sulfite liquor for reduction of greenhouse gas emissions from sulfite pulping mills

    Petersen, Abdul M; Haigh, Kate; Görgens, Johann F

    2014-01-01

    Background Flow sheet options for integrating ethanol production from spent sulfite liquor (SSL) into the acid-based sulfite pulping process at the Sappi Saiccor mill (Umkomaas, South Africa) were investigated, including options for generation of thermal and electrical energy from onsite bio-wastes, such as bark. Processes were simulated with Aspen Plus® for mass- and energy-balances, followed by an estimation of the economic viability and environmental impacts. Various concentration levels o...

  18. Synergetic Transformations of Multiple Pollutants Driven by Cr(VI)-Sulfite Reactions.

    Jiang, Bo; Liu, Yukun; Zheng, Jingtang; Tan, Minghui; Wang, Zhaohui; Wu, Mingbo

    2015-10-20

    Reduction of Cr(VI) is often deemed necessary to detoxify chromium contaminants; however, few investigations utilized this reaction for the purpose of treating other industrial wastewaters. Here a widely used Cr(VI)-sulfite reaction system was upgraded to simultaneously transform multiple pollutants, namely, the reduction of Cr(VI) and oxidation of sulfite and other organic/inorganic pollutants in an acidic solution. As(III) was selected as a probe pollutant to examine the oxidation capacity of a Cr(VI)-sulfite system. Both (•)OH and SO4(•-) were considered as the primary oxidants for As(III) oxidation, based on the results of electron spin resonance, fluorescence spectroscopy, and specific radicals quenching. As(III)-scavenging, oxidative radicals greatly accelerated Cr(VI) reduction and simultaneously consumed less sulfite. In comparison with a Cr(VI)-H2O2 system with 50 μM Cr(VI), Cr(VI), the sulfite system had excellent performance for both As(III) oxidation and Cr(VI) reduction at pH 3.5. Moreover, in this escalated process, less sulfite was required to reduce Cr(VI) than the traditional Cr(VI) reduction by sulfite process. This effectively improves the environmental compatibility of this Cr(VI) detoxification process, alleviating the potential for SO2 release and sulfate ion production in water. Generally, this study provides an excellent example of a "waste control by waste" strategy for the detoxification of multiple industrial pollutants. PMID:26384045

  19. Oxidation of Elemental Sulfur to Sulfite by Thiobacillus thiooxidans Cells

    Suzuki, Isamu; Chan, C W; Takeuchi, T L

    1992-01-01

    Thiobacillus thiooxidans cells oxidized elemental sulfur to sulfite, with 1 mol of O2 consumption per mol of sulfur oxidized to sulfite, when the oxidation of sulfite was inhibited with 2-n-heptyl-4-hydroxyquinoline N-oxide.

  20. Sulfonates and Organotrophic Sulfite Metabolism

    Cook, Alasdair M.; Theo H. M. Smits; Denger, Karin

    2007-01-01

    One is used to considering sulfite oxidation as part of a lithotrophic process (e.g. SorAB or Sox system), much of which involves neutral or ionic inorganic sulfur species on the outer surface of the cytoplasmic membrane. In contrast, the processes referred to in this chapter involve organic compounds, which (1) include a highly stable sulfonate substituent (C−SO3−), (2) are involved in the organotrophic growth of the organism and (3) much of whose metabolism takes place in the cytoplasm. Man...

  1. A sensitive and selective on-line amperometric sulfite biosensor using sulfite oxidase immobilized on a magnetite-gold-folate nanocomposite modified carbon-paste electrode.

    Sroysee, Wongduan; Ponlakhet, Kitayanan; Chairam, Sanoe; Jarujamrus, Purim; Amatatongchai, Maliwan

    2016-08-15

    We describe a novel amperometric sulfite biosensor, comprising a carbon-paste electrode (Fe3O4@Au-Cys-FA/CPE) modified with immobilized sulfite oxidase (SOx) on a gold-coated magnetite nanoparticle core, encased within a conjugated folic acid (FA) cysteine (Cys) shell. The biosensor electrode was fabricated using a polydimethylsiloxane (PDMS) and mineral oil mixture as binder, which also enhances the physical stability and sensitivity of the electrode. The developed biosensor displays good electrocatalytic activity toward oxidation of H2O2, which occurs by an enzymatic reaction between SOx and sulfite. The Fe3O4@Au-Cys-FA electrode exhibits good electrocatalytic activity, and has good retention of chemisorbed SOx on the electrode because of its large surface area. Sulfite was quantified using amperometric measurements from the Fe3O4@Au-Cys-FA/CPE biosensor, and using an in-house assembled flow cell at +0.35V (vs. Ag/AgCl), with a phosphate buffer carrier (0.10M, pH 7.0) at a flow rate of 0.8mLmin(-1). The system detects sulfite over the range 0.1-200mgL(-1) (r(2)=0.998), with a detection limit of 10µgL(-1) (3σ of blank). The system exhibits acceptable precision (%R.S.D.=3.1%), rapid sample throughput (109samplesh(-1)), and good stability (2w). The developed biosensor shows satisfactory tolerance to potential interferences, such as sugars, anions, ascorbic acid, and ethanol. We applied the developed method to the determination of sulfite content in wines and pickled food extracts, and our results are in good agreement with those obtained by the standard iodometric method. PMID:27260448

  2. Vanillin: Synthetic Flavoring from Spent Sulfite Liquor

    Hocking, Martin B.

    1997-09-01

    Separation of the lignin component of wood from the cellulose presents an opportunity to access various interesting products from the lignin fragments. The lignin represents availability of a sizable renewable resource. Vanillin, or 3-methoxy-4-hydroxybenzaldehyde, is one of a series of related substituted aromatic flavor constituents, and represents one of the potentially profitable possibilities. Vanillin production from the lignin-containing waste liquor obtained from acid sulfite pulping of wood began in North America in the mid 1930's. By 1981 one plant at Thorold, Ontario produced 60% of the contemporary world supply of vanillin. The process also simultaneously decreased the organic loading of the aqueous waste streams of the pulping process. Today, however, whilst vanillin production from lignin is still practiced in Norway and a few other areas, all North American facilities using this process have closed, primarily for environmental reasons. New North American vanillin plants use petrochemical raw materials. An innovation is needed to help overcome the environmental problems of this process before vanillin production from lignin is likely to resume here. Current interest in the promotion of chemicals production from renewable raw materials reinforces the incentive to do this.

  3. Sulfite Oxidase Activity Is Essential for Normal Sulfur, Nitrogen and Carbon Metabolism in Tomato Leaves

    Galina Brychkova

    2015-08-01

    Full Text Available Plant sulfite oxidase [SO; E.C.1.8.3.1] has been shown to be a key player in protecting plants against exogenous toxic sulfite. Recently we showed that SO activity is essential to cope with rising dark-induced endogenous sulfite levels in tomato plants (Lycopersicon esculentum/Solanum lycopersicum Mill. cv. Rheinlands Ruhm. Here we uncover the ramifications of SO impairment on carbon, nitrogen and sulfur (S metabolites. Current analysis of the wild-type and SO-impaired plants revealed that under controlled conditions, the imbalanced sulfite level resulting from SO impairment conferred a metabolic shift towards elevated reduced S-compounds, namely sulfide, S-amino acids (S-AA, Co-A and acetyl-CoA, followed by non-S-AA, nitrogen and carbon metabolite enhancement, including polar lipids. Exposing plants to dark-induced carbon starvation resulted in a higher degradation of S-compounds, total AA, carbohydrates, polar lipids and total RNA in the mutant plants. Significantly, a failure to balance the carbon backbones was evident in the mutants, indicated by an increase in tricarboxylic acid cycle (TCA cycle intermediates, whereas a decrease was shown in stressed wild-type plants. These results indicate that the role of SO is not limited to a rescue reaction under elevated sulfite, but SO is a key player in maintaining optimal carbon, nitrogen and sulfur metabolism in tomato plants.

  4. Amperometric Determination of Sulfite by Gas Diffusion-Sequential Injection with Boron-Doped Diamond Electrode

    Chinvongamorn, Chakorn; Pinwattana, Kulwadee; Praphairaksit, Narong; Imato, Toshihiko; Chailapakul, Orawon

    2008-01-01

    A gas diffusion sequential injection system with amperometric detection using a boron-doped diamond electrode was developed for the determination of sulfite. A gas diffusion unit (GDU) was used to prevent interference from sample matrices for the electrochemical measurement. The sample was mixed with an acid solution to generate gaseous sulfur dioxide prior to its passage through the donor channel of the GDU. The sulfur dioxide diffused through the PTFE hydrophobic membrane into a carrier solution of 0.1M phosphate buffer (pH 8)/0.1% sodium dodecyl sulfate in the acceptor channel of the GDU and turned to sulfite. Then the sulfite was carried to the electrochemical flow cell and detected directly by amperometry using the boron-doped diamond electrode at 0.95 V (versus Ag/AgCl). Sodium dodecyl sulfate was added to the carrier solution to prevent electrode fouling. This method was applicable in the concentration range of 0.2-20 mg SO32−/L and a detection limit (S/N = 3) of 0.05 mg SO32−/L was achieved. This method was successfully applied to the determination of sulfite in wines and the analytical results agreed well with those obtained by iodimetric titration. The relative standard deviations for the analysis of sulfite in wines were in the range of 1.0-4.1 %. The sampling frequency was 65 h−1.

  5. Amperometric Determination of Sulfite by Gas Diffusion- Sequential Injection with Boron-Doped Diamond Electrode

    Orawon Chailapakul

    2008-03-01

    Full Text Available A gas diffusion sequential injection system with amperometric detection using aboron-doped diamond electrode was developed for the determination of sulfite. A gasdiffusion unit (GDU was used to prevent interference from sample matrices for theelectrochemical measurement. The sample was mixed with an acid solution to generategaseous sulfur dioxide prior to its passage through the donor channel of the GDU. Thesulfur dioxide diffused through the PTFE hydrophobic membrane into a carrier solution of 0.1 M phosphate buffer (pH 8/0.1% sodium dodecyl sulfate in the acceptor channel of theGDU and turned to sulfite. Then the sulfite was carried to the electrochemical flow cell anddetected directly by amperometry using the boron-doped diamond electrode at 0.95 V(versus Ag/AgCl. Sodium dodecyl sulfate was added to the carrier solution to preventelectrode fouling. This method was applicable in the concentration range of 0.2-20 mgSO32−/L and a detection limit (S/N = 3 of 0.05 mg SO32−/L was achieved. This method wassuccessfully applied to the determination of sulfite in wines and the analytical resultsagreed well with those obtained by iodimetric titration. The relative standard deviations forthe analysis of sulfite in wines were in the range of 1.0-4.1 %. The sampling frequency was65 h−1.

  6. Rapid microstill determination of free and total sulfite in wine with conductimetric detection.

    McLeod, Stan; Davey, David E

    2007-09-26

    The development and optimization of on-line microdistillation for free and total sulfite (S(IV)) in grape juice and wine is reported. The microstill used both heat and an air stream to separate sulfur dioxide from the wine samples; the distillation product was captured in a peroxide solution, and converted to sulfuric acid, mirroring accepted industry practice. Measured from 1 to 300 mgL(-1) as SO(2) by conductance, sample throughputs of 60 h(-1) for free and 20 h(-1) for total sulfite were achieved. Data for bound S(IV) emphasises the slow kinetics of release reactions in some wines. The microstill method is more efficient for total sulfite than the accepted manual technique. Good correlation was found between the microstill and manual methods under specified control conditions. PMID:17903466

  7. Highly sensitive and stable electrochemical sulfite biosensor incorporating a bacterial sulfite dehydrogenase.

    Kalimuthu, Palraj; Tkac, Jan; Kappler, Ulrike; Davis, Jason J; Bernhardt, Paul V

    2010-09-01

    This paper describes a highly sensitive electrochemical (voltammetric) determination of sulfite using a combination of Starkeya novella sulfite dehydrogenase (SDH), horse heart cytochrome c (cyt c), and a self-assembled monolayer of 11-mercaptoundecanol (MU) cast on a gold electrode. The biosensor was optimized in terms of pH and the ratio of cyt c/SDH. The electrocatalytic oxidation current of sulfite increased linearly from 1 to 6 microM at the enzyme-modified electrode with a correlation coefficient of 0.9995 and an apparent Michaelis constant (K(M,app)) of 43 microM. Using an amperometric method, the low detection limit for sulfite at the enzyme-modified electrode was 44 pM (signal-to-noise ratio = 3). The modified electrode retained a stable response for 3 days while losing only ca. 4% of its initial sensitivity during a 2 week storage period in 50 mM Tris buffer solution at 4 degrees C. The enzyme electrode was successfully used for the determination of sulfite in beer and white wine samples. The results of these electrochemical analyses agreed well with an independent spectrophotometric method using Ellman's reagent, but the detection limit was far superior using the electrochemical method. PMID:20698497

  8. Thermodynamic fundamentals of ferrous cake sulfitization

    Tyurin, A. G.; Vasekha, M. V.; Biryukov, A. I.

    2016-03-01

    The Pourbaix diagrams of the systems SO 4 2- -SO 3 2- -H2O and iron hydroxide (oxide)-H2O are refined. The E(pH) dependence of the sulfitization of iron(III) hydroxide is refined with allowance for the regions of predominant phase constituents of the systems. The potential E-pH electrochemical equilibrium diagrams of the systems Fe(OH)3-H2SO4-SO 3 2- -H2O, FeOOH-H2SO4-SO 3 2- -H2O, and Fe2O3-H2SO4-SO 3 2- -H2O are plotted. These diagrams can be considered as a thermodynamic basis for the sulfite conversion of the ferrous cake of copper-nickel production.

  9. Extraction and Recovery of Lead from Kaldo Slag by Acetate Acid and Sodium Acetate Leaching and Sodium Sulfite Precipitation%用乙酸-乙酸钠浸出及亚硫酸钠沉淀分离回收卡尔多炉渣中的铅

    吕建军; 肖连生; 张启修; 黄芍英; 胡磊; 曾之琪

    2013-01-01

    采用乙酸-乙酸钠溶液浸出卡尔多炉渣中的铅,用无水亚硫酸钠沉淀分离浸出液中的铅,沉铅滤液脱硫(加氢氧化钡)后返回浸出工序,研究了相关工艺参数对铝直收率及亚硫酸铅纯度的影响.结果表明:在搅拌速度为300 r/min,浸出温度为室温(25℃),乙酸、乙酸钠浓度分别为1 mol/L和2 mol/L,液固比5∶1,浸出时间2h时,铅的浸出率可达到99.1%,浸出液含铅78.3 g/L;在搅拌速度200 r/min,沉淀温度为室温(25℃),无水亚硫酸钠过量系数1.25,沉淀时间20 min时,沉铅滤液余铅含量可降至4×10-6,亚硫酸铅纯度达到97.4%,铅的直收率可达到98%以上;沉铅滤液除硫酸根后,补充乙酸、乙酸钠至摩尔浓度分别为1mol/L和2 mol/L,返回浸出工序,按浸出的最优条件处理同样的卡尔多炉渣,铅的浸出率可以达到98.1%,实现了浸出剂的闭路循环.%Lead was leached from Kaldo slag using acetate acid and sodium acetate, then precipitated and extracted from the leaching liquor by sodium sulfite. The lead-extracted filtrate was returned to the leaching process after being desulfurized by barium hydroxide. The effects of related process parameters on aluminum recovery and lead sulfite purity were investigated. The results show that under the conditions such as stirring speed of 300 r/min, leaching temperature of 251, acetate acid concertration of 1 mol/L, sodium acetate concertration of 2 mol/L, liquid-solid ratio of 5:1 and leaching time of 2 h, the leaching rate of lead can reach to 99.1%, with a lead content of 78.3 g/L in the leaching liquor. Under the following conditions; stirring speed of 200 r/min, precipitation temperature of 25 ℃, an excess coefficient of hydrous sodium sulfite of 1.25 and precipitation time of 20 min, the lead content in the lead-extracted filtrate can be decreased to 4 × 10-6 while the purity of lead sulfite and lead recovery reaches to 97.4% and 98% respectively. After desulfurization

  10. Destruction of tryptophan during the aerobic oxidation of sulfite ions

    Tryptophan was rapidly destroyed aerobically in the presence of Mn2+ and sulfite. The rate of destruction was greatly increased when horseradish peroxidase was added. The optimal pH for the reaction was 8.0. The destruction of tryptophan was dependent on the aerobic oxidation of sulfite. Superoxide dismutase inhibited sulfite oxidation and thus inhibited the tryptophan destruction. Tracer studies using 14C indicate that tryptophan is converted into at least 4 products

  11. Molecular Basis for Enzymatic Sulfite Oxidation -- HOW THREE CONSERVED ACTIVE SITE RESIDUES SHAPE ENZYME ACTIVITY

    Bailey, Susan; Rapson, Trevor; Johnson-Winters, Kayunta; Astashkin, Andrei; Enemark, John; Kappler, Ulrike

    2008-11-10

    Sulfite dehydrogenases (SDHs) catalyze the oxidation and detoxification of sulfite to sulfate, a reaction critical to all forms of life. Sulfite-oxidizing enzymes contain three conserved active site amino acids (Arg-55, His-57, and Tyr-236) that are crucial for catalytic competency. Here we have studied the kinetic and structural effects of two novel and one previously reported substitution (R55M, H57A, Y236F) in these residues on SDH catalysis. Both Arg-55 and His-57 were found to have key roles in substrate binding. An R55M substitution increased Km(sulfite)(app) by 2-3 orders of magnitude, whereas His-57 was required for maintaining a high substrate affinity at low pH when the imidazole ring is fully protonated. This effect may be mediated by interactions of His-57 with Arg-55 that stabilize the position of the Arg-55 side chain or, alternatively, may reflect changes in the protonation state of sulfite. Unlike what is seen for SDHWT and SDHY236F, the catalytic turnover rates of SDHR55M and SDHH57A are relatively insensitive to pH (~;;60 and 200 s-1, respectively). On the structural level, striking kinetic effects appeared to correlate with disorder (in SDHH57A and SDHY236F) or absence of Arg-55 (SDHR55M), suggesting that Arg-55 and the hydrogen bonding interactions it engages in are crucial for substrate binding and catalysis. The structure of SDHR55M has sulfate bound at the active site, a fact that coincides with a significant increase in the inhibitory effect of sulfate in SDHR55M. Thus, Arg-55 also appears to be involved in enabling discrimination between the substrate and product in SDH.

  12. Effect of inhibitors on macroscopical oxidation kinetics of calcium sulfite

    ZHAO Yi; WANG Li-dong; WANG Xiao-ming; LI Qiang-wei; XU Pei-yao

    2005-01-01

    In the presence of inhibitors, the macroscopical oxidation kinetics of calcium sulfite, the main byproduct in wet limestone scrubbing, was studied for the first time by adding different inhibitors and varying pH, concentration of calcium sulfite, oxygen partial pressure, concentration of inhibitors and temperature. The mathematical model about the general oxidation reaction was established,which was controlled by three steps involving dissolution of calcium sulfite, mass transfer of oxygen and chemical reaction in the solution.It was concluded that the general reaction was controlled by mass transfer of oxygen under uncatalyzed conditions, while it was controlled by dissolution of calcium sulfite after adding three kinds of inhibitors. Thus, the theory was provided for investigating the mechanism and oxidation kinetics of sulfite. The beneficial references were also supplied for design of oxidation technics in the wet limestone scrubbing.

  13. Sulfite oxidase biosensors based on tetrathiafulvalene modified screen-printed carbon electrodes for sulfite determination in wine.

    Molinero-Abad, Begoña; Alonso-Lomillo, M Asunción; Domínguez-Renedo, Olga; Arcos-Martínez, M Julia

    2014-02-17

    Screen-printed carbon electrodes have been modified with tetrathiafulvalene and sulfite oxidase enzyme for the sensitive and selective detection of sulfite. Amperometric experimental conditions were optimized taking into account the importance of quantifying sulfite in wine samples and the inherent complexity of these samples, particularly red wine. The biosensor responds to sulfite giving a cathodic current (at +200 mV vs screen-printed Ag/AgCl electrode and pH 6) in a wide concentration range, with a capability of detection of 6 μM (α=β=0.05) at 60°C. The method has been applied to the determination of sulfite in white and red samples, with averages recoveries of 101.5% to 101.8%, respectively. PMID:24491762

  14. Determination of total sulfite in wine by ion chromatography after in-sample oxidation.

    Koch, Matthias; Köppen, Robert; Siegel, David; Witt, Angelika; Nehls, Irene

    2010-09-01

    Sulfur dioxide (SO2) or sulfites are the most common preservatives used in winemaking. The level of total SO2 is subject to regulation. Currently, the regulatory determination of total SO2 (including sulfites) is done by the optimized Monier-Williams (OMW) method, which includes time-consuming distillation and titration steps. This paper describes the development and application of an alternative, rapid, straightforward, and reliable method for the determination of total sulfite in wine. In this method, a simple oxidation step using alkaline hydrogen peroxide (H2O2) solution is followed by ion chromatographic (IC) analysis of sulfate coupled with conductometric detection. Thirteen wines were analyzed in order to compare the in-sample oxidation method with the OMW-procedure. A t-test revealed satisfying compliance regarding sample preparation, i.e., alkaline H2O2 treatment and acidic distillation (OMW method). Comparable results were also obtained between IC analysis and acid/base titration. Our results indicate that the novel method (limit of quantification: 4 mg SO2 L(-1)) is well suited for the cost-efficient monitoring of regulatory limits. PMID:20690603

  15. Fluorometric determination of total and bound sulfite in wine by N-(9-acridinyl)maleimide.

    Akasaka, K; Ohrui, H; Meguro, H; Suzuki, T; Miwa, H

    1993-01-01

    N-(9-Acridinyl)maleimide (NAM) reacts with sulfite in wine and gives strong fluorescent derivatives that lead to highly sensitive fluorometry of both total and bound sulfite in wine. Values of free and bound sulfite in wine determined by the NAM method and the modified Rankine method agreed. Sulfite was determined in wine within 2 h. PMID:8286979

  16. Catalytic oxidation of calcium sulfite in solution/aqueous slurry

    WU Xiao-qin; WU Zhong-biao; WANG Da-hui

    2004-01-01

    Forced oxidation of calcium sulfite aqueous slurry is a key step for the calcium-based flue gas desulfurization(FGD) residue. Experiments were conducted in a semi-batch system and a continuous flow system on lab scales. The main reactor in semi-batch system is a 1000 ml volume flask. It has five necks for continuous feeding of gas and a batch of calcium sulfite solution/aqueous slurry. In continuous flow system, the main part is a jacketed Pyrex glass reactor in which gas and solution/aqueous slurry are fed continuously. Calcium sulfite oxidation is a series of complex free-radical reactions. According to experimental results and literature data, the reactions are influenced significantly by manganese as catalyst. At low concentration of manganese and calcium sulfite, the reaction rate is dependent on 1.5 order of sulfite concentration, 0.5 order of manganese concentration, and zero order of oxygen concentration in which the oxidation is controlled by chemical kinetics. With concentrations of calcium sulfite and manganese increasing, the reactions are independent gradually on the constituents in solution but are impacted by oxygen concentration. Manganese can accelerate the free-radical reactions, and then enhances the mass transfer of oxygen from gas to liquid. The critical concentration of calcium sulfite is 0.007 mol/L, manganese is 10-4 mol/L, and oxygen is of 0.2-0.4 atm.

  17. Enzymatic determination of sulfite in foods: NMKL interlaboratory study.

    Edberg, U

    1993-01-01

    An enzymatic method for the determination of sulfite in foods was collaboratively studied in Nordic industry and government laboratories. The sulfite in liquid foods or extracts of solid foods is analyzed according to the following principle: Sulfite ions are oxidized to sulfate ions by oxygen in the presence of sulfite oxidase, thereby forming hydrogen peroxide. Hydrogen peroxide is transformed to water by reduced nicotinamide adenine dinucleotide (NADH) in the presence of NADH peroxidase. In this reaction, NAD+ is formed (and NADH is consumed) in amounts proportional to the sulfite concentration. Consumption of NADH can be measured spectrophotometrically at 340 nm. The method was collaboratively tested in 2 separate studies with high and low levels of sulfite tested. Results of both studies are reported here. The study samples consisted of potato flakes, wine, juice, and dried apples containing between 0 and about 960 mg SO2/kg. Eleven laboratories participated in the full study and analyzed 12 samples. Six laboratories analyzed 8 samples in the complementary study. Before statistical evaluation of the collaborative study data, results were adjusted for the time-dependent decrease of sulfite in the case of materials with high sulfite content (dried apples and wine). For 2 blind duplicate samples of wine containing 75 mg SO2/kg, the relative standard deviation for repeatability (RSDr, within-laboratory variation) was 3.9%. Relative standard deviation for reproducibility (RSDR, between-laboratory variation) was 7.6%. For 2 samples of dried apples containing 800 and 960 mg SO2/kg, an RSDr value of 13.3% and an RSDR value of 13.9% were calculated.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8448446

  18. Comparison of three liquid chromatographic methods with FDA optimized Monier-Williams method for determination of total sulfite in foods.

    Lawrence, J F; Chadha, R K; Ménard, C

    1990-01-01

    Three liquid chromatographic (LC) methods employing amperometric detection were compared with the collaboratively studied FDA optimized Monier-Williams distillation method for the determination of total sulfite in 5 food types. The foods included lemon juice, white wine, instant mashed potatoes, golden raisins, and onion flakes. Two of the LC methods (one employing headspace sampling and the other direct injection) used ion-exchange chromatography with a basic mobile phase (pH about 10.8) and a glassy carbon electrode; the third (employing direct injection) used ion-exclusion chromatography with an acidic mobile phase (pH about 2) and a platinum electrode. All 4 methods produced similar results for the wine, lemon juice, and raisins. Results were different for instant mashed potatoes and onion flakes. The headspace-LC method and direct ion-exclusion LC method, both of which employed an alkaline sample extraction, yielded significantly higher values for sulfite in instant potatoes than did the other 2 methods. A large interfering peak with both direct LC methods prevented quantitation of sulfite in the onion flakes. All methods can detect sulfite as low as about 1 microgram/g in 4 of 5 food types examined. PMID:2312516

  19. Cloning and characterization of sulfite dehydrogenase, two c-type cytochromes, and a flavoprotein of Paracoccus denitrificans GB17: essential role of sulfite dehydrogenase in lithotrophic sulfur oxidation.

    Wodara, C; Bardischewsky, F; Friedrich, C G

    1997-08-01

    A 13-kb genomic region of Paracoccus dentrificans GB17 is involved in lithotrophic thiosulfate oxidation. Adjacent to the previously reported soxB gene (C. Wodara, S. Kostka, M. Egert, D. P. Kelly, and C. G. Friedrich, J. Bacteriol. 176:6188-6191, 1994), 3.7 kb were sequenced. Sequence analysis revealed four additional open reading frames, soxCDEF. soxC coded for a 430-amino-acid polypeptide with an Mr of 47,339 that included a putative signal peptide of 40 amino acids (Mr of 3,599) with a RR motif present in periplasmic proteins with complex redox centers. The mature soxC gene product exhibited high amino acid sequence similarity to the eukaryotic molybdoenzyme sulfite oxidase and to nitrate reductase. We constructed a mutant, GBsoxC delta, carrying an in-frame deletion in soxC which covered a region possibly coding for the molybdenum cofactor binding domain. GBsoxC delta was unable to grow lithoautotrophically with thiosulfate but grew well with nitrate as a nitrogen source or as an electron acceptor. Whole cells and cell extracts of mutant GBsoxC delta contained 10% of the thiosulfate-oxidizing activity of the wild type. Only a marginal rate of sulfite-dependent cytochrome c reduction was observed from cell extracts of mutant GBsoxC delta. These results demonstrated that sulfite dehydrogenase was essential for growth with thiosulfate of P. dentrificans GB17. soxD coded for a periplasmic diheme c-type cytochrome of 384 amino acids (Mr of 39,983) containing a putative signal peptide with an Mr of 2,363. soxE coded for a periplasmic monoheme c-type cytochrome of 236 amino acids (Mr of 25,926) containing a putative signal peptide with an Mr of 1,833. SoxD and SoxE were highly identical to c-type cytochromes of P. denitrificans and other organisms. soxF revealed an incomplete open reading frame coding for a peptide of 247 amino acids with a putative signal peptide (Mr of 2,629). The deduced amino acid sequence of soxF was 47% identical and 70% similar to the sequence

  20. Analysis of commercial proanthocyanidins. Part 2: An electrospray mass spectrometry investigation into the chemical composition of sulfited quebracho (Schinopsis lorentzii and Schinopsis balansae) heartwood extract.

    Venter, Pieter B; Senekal, Nadine D; Amra-Jordaan, Maryam; Bonnet, Susan L; Van der Westhuizen, Jan H

    2012-06-01

    Proanthocyanidins (PACs) are natural plant-derived polymers used in leather tanning, wood adhesives, water purification, and mud additives for oil drilling. Quebracho (Schinopsis lorentzii and Schinopsis balansae) heartwood and mimosa (Acacia mearnsii) bark extracts are the major industrial sources of PACs. These commercial extracts are often sulfited via treatment with sodium hydrogen sulfite to reduce their viscosity and increase their solubility in water. An ESI-MS investigation into the molecular composition of sulfited (cold-water-soluble) quebracho heartwood extract indicates that sulfitation of the PACs occurs via S(N)2 attack of a sulfite ion at both C-2 and C-4 of the constituent flavan-3-ol monomer extender units. Attack at C-2 leads to the opening of the pyran ring. This releases an additional electron-donating phenolic hydroxy group on the A-ring and renders the extract more nucleophilic and suitable for the manufacturing of adhesives. Attack at C-4 leads to interflavanyl bond fission and decrease of the PAC oligomer chain length. The introduction of sulfonic acid moieties at C-2 or C-4 increases the polarity and water solubility of the hot water soluble (unsulfited) extract and transforms it into a cold-water-soluble extract. PMID:22513010

  1. Polyphenols content, phenolics profile and antioxidant activity of organic red wines produced without sulfur dioxide/sulfites addition in comparison to conventional red wines.

    Garaguso, Ivana; Nardini, Mirella

    2015-07-15

    Wine exerts beneficial effects on human health when it is drunk with moderation. Nevertheless, wine may also contain components negatively affecting human health. Among these, sulfites may induce adverse effects after ingestion. We examined total polyphenols and flavonoids content, phenolics profile and antioxidant activity of eight organic red wines produced without sulfur dioxide/sulfites addition in comparison to those of eight conventional red wines. Polyphenols and flavonoids content were slightly higher in organic wines in respect to conventional wines, however differences did not reach statistical significance. The phenolic acids profile was quite similar in both groups of wines. Antioxidant activity was higher in organic wines compared to conventional wines, although differences were not statistically significant. Our results indicate that organic red wines produced without sulfur dioxide/sulfites addition are comparable to conventional red wines with regard to the total polyphenols and flavonoids content, the phenolics profile and the antioxidant activity. PMID:25722174

  2. Role of sulfite additives in wine induced asthma: single dose and cumulative dose studies

    Vally, H; Thompson, Van P.

    2001-01-01

    BACKGROUND—Wine appears to be a significant trigger for asthma. Although sulfite additives have been implicated as a major cause of wine induced asthma, direct evidence is limited. Two studies were undertaken to assess sulfite reactivity in wine sensitive asthmatics. The first study assessed sensitivity to sulfites in wine using a single dose sulfited wine challenge protocol followed by a double blind, placebo controlled challenge. In the second study a cumulative dose su...

  3. Determination of total sulfite in wine. Zone electrophoresis-isotachophoresis quantitation of sulfate on a chip after an in-sample oxidation of total sulfite.

    Masár, Marián; Danková, Mariana; Olvecká, Eva; Stachurová, Adela; Kaniansky, Dusan; Stanislawski, Bernd

    2005-08-19

    This work deals with the determination of total sulfite in wine. The determination combines an in-sample hydrogen peroxide oxidation of total sulfite in alkalized wine to sulfate with the separation and quantitation of the latter anion by zone electrophoresis (ZE) on-line coupled with isotachophoresis (ITP) on a column-coupling chip. Sample clean up, integrated into the ITP-ZE separation, eliminated wine matrix in an extent comparable to that provided by a highly selective distillation isolation of sulfite. At the same time, conductivity detection, employed to the detection of sulfate in the ZE stage of the ITP-ZE combination, provided for sulfate the concentration limit of detection corresponding to a 90 microg/l concentration of sulfite in the loaded sample (0.9 microl). Such a detectability allowed a reproducible quantitation of total sulfite when its concentration in wine was 15 mg/l. Formaldehyde binding of free sulfite in wine, included into the pre-column sample preparation, prevented an uncontrolled oxidation of this sulfite form. This step contributed to an unbiased determination of sulfate present in the original wine sample (this determination corrected for the concentration of sulfate determined in the sample after the peroxide oxidation of sulfite to the value equivalent to the total sulfite). The 99-101% recoveries of sulfite, determined for appropriately spiked wine samples, indicate a very good accuracy of the present method. Such a statement also supports excellent agreements of the results of quantitation based on the in-sample peroxide oxidation of the total sulfite (bound sulfite released at a high pH) with those in which this analyte was isolated from wine by distillation (bound sulfite released at a very low pH). PMID:16114242

  4. Kinetics of stripping of gold loaded in DBC organic phase by sodium sulfite

    2006-01-01

    The kinetics of stripping of gold loaded in dibutyl carbito (DBC) organic phase by sodium sulfite was investipseudo-first-order reaction. The stripping rate of gold was in direct proportion to interfacial area, concentration of sodium sulfite and reaction temperature. The experimental results showed that the process of stripping gold was controlled by interping by sodium sulfite.

  5. 21 CFR 130.9 - Sulfites in standardized food.

    2010-04-01

    ... incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51, and the refinements of the... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Sulfites in standardized food. 130.9 Section 130.9 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED)...

  6. Mechanism of the Ferrocyanide-Iodate-Sulfite Oscillatory Chemical Reaction.

    Horváth, Viktor; Epstein, Irving R; Kustin, Kenneth

    2016-03-31

    Existing models of the ferrocyanide-iodate-sulfite (FIS) reaction seek to replicate the oscillatory pH behavior that occurs in open systems. These models exhibit significant differences in the amplitudes and waveforms of the concentration oscillations of such intermediates as I(-), I3(-), and Fe(CN)6(3-) under identical conditions and do not include several experimentally found intermediates. Here we report measurements of sulfite concentrations during an oscillatory cycle. Knowing the correct concentration of sulfite over the course of a period is important because sulfite is the main component that determines the buffer capacity, the pH extrema, and the amount of oxidizer (iodate) required for the transition to low pH. On the basis of this new result and recent experimental findings on the rate laws and intermediates of component processes taken from the literature, we propose a mass action kinetics model that attempts to faithfully represent the chemistry of the FIS reaction. This new comprehensive mechanism reproduces the pH oscillations and the periodic behavior in [Fe(CN)6(3-)], [I3(-)], [I(-)], and [SO3(2-)]T with characteristics similar to those seen in experiments in both CSTR and semibatch arrangements. The parameter ranges at which stationary and oscillatory behavior is exhibited also show good agreement with those of the experiments. PMID:26949219

  7. Sulfite triggers sustained calcium overload in cultured cortical neurons via a redox-dependent mechanism.

    Wang, Xiao; Cao, Hui; Guan, Xin-Lei; Long, Li-Hong; Hu, Zhuang-Li; Ni, Lan; Wang, Fang; Chen, Jian-Guo; Wu, Peng-Fei

    2016-09-01

    Sulfite is a compound commonly used as preservative in foods and pharmaceuticals. Many studies have examined the neurotoxicity of sulfite, but its effect on neuronal calcium homeostasis has not yet been reported. Here, we observed the effect of sulfite on the cytosolic free calcium concentration ([Ca(2+)]i) in cultured cortical neurons using Fura-2/AM based calcium imaging technique. Sulfite (250-1000μM) caused a sustained increase in [Ca(2+)]i in the neurons via a dose-dependent manner. In Ca(2+)-free solution, sulfite failed to increase [Ca(2+)]i. After the depletion of the intracellular calcium store, the effect of sulfite on the [Ca(2+)]i was largely abolished. Pharmacological inhibition of phospholipase C (PLC)-inositol 1,4,5-triphosphate (IP3) signaling pathway blocked sulfite-induced increase of [Ca(2+)]i. Interestingly, antioxidants such as trolox and dithiothreitol, abolished the increase of [Ca(2+)]i induced by sulfite. Exposure to sulfite triggered generation of sulfur- and oxygen-centered free radicals in neurons and increased oxidative stress both in the cultured cortical neurons and the prefrontal cortex of rats. Furthemore, sulfite decreased cell viability in cultured cortical neurons via a calcium-dependent manner. Thus, our current study suggests that the redox-dependent calcium overload triggered by sulfite in cortical neuronsmay be involved in its neurotoxicity. PMID:27313092

  8. APPLICATION OF ALKALINE SULFITE PULPING ON CORN STALKS

    Ahmad Jahan Latibari

    2011-02-01

    Full Text Available Alkaline sulfite pulping of corn stalks was investigated to produce supplementary pulp for corrugating board manufacture. Three pulping temperatures (125, 145, and 165°C and five active alkali charges (10, 12, 14, 16, and 18% were used. Cooking time at 30 minutes, Na2SO3/ NaOH ratio at 50:50, and liquor to residue ratio of 8:1 were kept constant. The highest total yield (61.9% was reached applying the treatment combination of 125°C and 10% active alkali, and the lowest total yield (42.5% was related to 165°C and 16% chemical. The influence of sodium sulfite/sodium hydroxide ratios was studied applying different ratios (30:70, 40:60, 50:50, 60:40, and 70:30 at constant time and temperature of 30 minutes and 145°C respectively and 14 and 16% active alkali. Pulping condition; 16% active alkali, 30 minutes time, 145°C pulping temperature and varying ratios of sodium sulfite/sodium hydroxide were selected for pulp strength evaluation. The results of handsheet evaluation indicated that 16% active alkali, 30 minutes pulping at 145ºC and sodium sulfite/sodium hydroxide ratio of 50:50 is the optimum pulping condition for corn stalks. Tear, tensile, and burst indices and breaking length of this pulp were measured as 10.53 mN.m2g-1, 62.4 N.mg-1, 3.80 kPa.m2g-1, and 6.07 km, respectively.

  9. Different mechanisms of resistance modulate sulfite tolerance in wine yeasts.

    Nadai, Chiara; Treu, Laura; Campanaro, Stefano; Giacomini, Alessio; Corich, Viviana

    2016-01-01

    From a technological point of view, yeast resistance to sulfite is of great interest and represents an important technological character for winemaking. Several mechanisms are involved, and strain-dependent strategies to obtain SO2 resistance can deeply influence wine quality, although this choice is less relevant in determining the technological performance of the strain during fermentation. In this study, to better understand the strain-specific mechanisms of resistance, 11 Saccharomyces cerevisiae strains, whose genomes have been previously sequenced, were selected. Their attitude towards sulfites, in terms of resistance and production, was evaluated, and RNA-sequencing of four selected strains was performed during fermentation process in synthetic grape must in the presence of SO2. Results demonstrated that at molecular level, the physical effect of SO2 triggered multiple stress responses in the cell and high tolerance to general enological stressing condition increased SO2 resistance. Adaptation mechanism due to high basal gene expression level rather than specific gene induction in the presence of sulfite seemed to be responsible in modulating strain resistance. This mechanism involved higher basal gene expression level of specific cell wall proteins, enzymes for lipid biosynthesis, and enzymes directly involved in SO2 assimilation pathway and efflux. PMID:26615396

  10. Fluorometric determination of sulfite in wine by N-(9-acridinyl)maleimide.

    Akasaka, K; Matsuda, H; Ohrui, H; Meguro, H; Suzuki, T

    1990-01-01

    A highly sensitive fluorometric method for determining sulfite in wine is reported. N-(9-Aciridinyl)maleimide (NAM) reacted with the sulfite in wine quantitatively and gave strong fluorescent derivatives. The determinations were conducted by batch and high-performance liquid chromatographic methods. Sulfite contents in wine by NAM methods and the conventional methods showed good accordance. The sample size could be reduced to less than 1/10,000 by the NAM methods. PMID:19130675

  11. Inhibition of tyrosinase-mediated enzymatic browning by sulfite and natural alternatives

    Kuijpers, T.F.M.; Vincken, J.P.

    2013-01-01

    Although sulfite is widely used to counteract enzymatic browning, its mechanism has remained largely unknown. We describe a double inhibitory mechanism of sulfite on enzymatic browning, affecting both the enzymatic oxidation of phenols into o‑quinones, as well as the non‑enzymatic reactions of these

  12. Spectrophotometric Determination of Total Sulfite in White Wine Samples Using Crude Extracts from Flowers

    Flora Barbosa Soares, Márlon Herbert; Ramos, Luiz Antonio; Tadeu Gomes Cavalheiro, Éder

    2002-09-01

    A didactic spectrophotometric method for determining the sulfite content in white wine samples is proposed. It is based upon a discoloring reaction between flower anthocyanins and the sulfite in basic media. Students' results obtained from iodometric data agreed well with results obtained by the proposed procedure. The use of natural dyes attracted students' interest, enhancing the learning process.

  13. Reevaluation of Monier-Williams method for determining sulfite in food.

    Warner, C R; Daniels, D H; Joe, F L; Fazio, T

    1986-01-01

    The Monier-Williams distillation procedure has a long history of successful use for determining sulfite in fruit products and wine; however, a systematic evaluation of its accuracy and precision with other food matrices has not been undertaken. We found that the Monier-Williams distillation yielded greater than 90% recovery of sulfite added to foods such as table grapes, hominy, dried mangoes, and lemon juice. Less than 85% recovery was obtained with broccoli, soda crackers, cheese-peanut butter crackers, mushrooms, and potato chips. These results may, in fact, accurately reflect the residual levels of sulfite if a portion of the sulfite undergoes irreversible reaction with some food components. Analysis of commercial food products gave sulfite levels ranging from 1400 ppm in dried apple slices to 25 ppm in cream sherry. PMID:3949694

  14. Enhancing hemicelluloses removal from a softwood sulfite pulp.

    Li, Jianguo; Zhang, Hongjie; Duan, Chao; Liu, Yishan; Ni, Yonghao

    2015-09-01

    Hemicelluloses removal is highly desirable in many biomass processes, including the pretreatment steps of the bioconversion for ethanol production, production of high-quality dissolving pulps. In this study, a sequential treatment consisting of pulp fractionation, followed by caustic treatment to remove hemicelluloses from a softwood sulfite pulp, was investigated. The long-fiber fraction obtained after pulp fractionation, had a lower hemicelluloses content and smaller specific surface area, but larger pore diameter than the short-fiber fraction. The fiber fractions were subsequently treated in a cold caustic extraction (CCE) or hot caustic extraction (HCE). Results showed that hemicelluloses removal in the long-fiber fraction was more pronounced than the short-fiber fraction in both CCE and HCE processes. Other parameters, such as hemicelluloses removal selectivity, yield were studied. The underlying explanations were given. PMID:26004557

  15. ALKALINE SULFITE-ALCOHOL DELIGNIFICATION OF STEMS OF HELIANTHUS ANNUUS AND BUNIAS

    Трембус, Ірина Віталіївна; Плосконос, Віктор Григорович; Швидкий, А. М.

    2015-01-01

    Stems of Helianthus annuus and Bunias can be processed into semi-finished fiber products using alkaline sulfite-alcohol delignification. These semi-finished fiber products in their physical and mechanical characteristics are similar to those of the pulp of hardwood. The dependences of quality semi-finished fiber products on the temperature and duration of delignification are obtained.Keywords: alkaline sulfite-alcohol delignification, semi-finished fiber products, Helianthus annuus, Bunias

  16. Effects of low concentrations of bisulfite--sulfite and nitrite on microorganisms

    Wodzinski, R.S.; Labeda, D.P.; Alexander, M.

    1978-04-01

    A wide range of microorganisms was tested to determine their sensitivity to low concentrations of bisulfite-sulfite and nitrite, solubility products of SO/sub 2/ and NO/sub 2/, respectively. Photosynthesis by blue-green algae (cyanobacteria) was more strongly inhibited by 0.1 mM bisulfite-sulfite and 1 mM nitrite at pH 6.0 than photosynthesis by eucaryotic algae and respiration of bacteria, fungi, and protozoa. At pH 7.7, blud-green algae were still more sensitive to busulfite-sulfite and nitrite than eurcaryotic algae, but the toxicity of bisulfite-sulfite and nitrite decreased as the pH increased. Photosynthesis by Anabaena flos-aquae at pH 6.0 was inhibited 25% by a bisulfite-sulfite concentration of 10 ..mu..M and 15% by a nitrite concentration of 50 ..mu..M. Photosynthesis by the blud-green alga, Lyngbya sp., was not exceptionally sensitive to chlorate and thiosulfate. Acetylene-reducing activity of Beijerinckia indica was completely inhibited by 0.1 mM bisulfite-sulfite at pH 4.0, the suppression being decreased with increasing pH.

  17. Effect of gel network on pattern formation in the ferrocyanide-iodate-sulfite reaction.

    Ueno, Tomonaga; Yoshida, Ryo

    2011-06-01

    Stationary patterns have been researched experimentally since the discovery of the Turing pattern in the chlorite-iodide-malonic acid (CIMA) reaction and the self-replicating spot pattern in the ferrocyanide-iodate-sulfite (FIS) reaction. In this study, we reproduced the pattern formation in the FIS reaction by using poly(acrylamide) gels. Gels with different swelling ratios were prepared to use as a medium. The effect of the swelling ratio was compared with the effect of thickness. It was found that the swelling ratio greatly influenced pattern formation. Oscillating spot patterns appeared at high swelling ratios, and lamellar patterns appeared at a low swelling ratio. Self-replicating spot patterns appeared in between the two areas. The front velocities, which were observed in the initial stage of pattern formation, depended on the swelling ratio. Furthermore, this dependence obeys the free volume theory of diffusion. These results provide evidence that the change in front velocities is caused by a change in diffusion. Pattern formation can be controlled not only by thickness but also by swelling ratio, which may be useful for creating novel pattern templates. PMID:21557556

  18. Enhanced generation of hydroxyl radical and sulfur trioxide anion radical from oxidation of sodium sulfite, nickel(II) sulfite, and nickel subsulfide in the presence of nickel(II) complexes.

    Shi, X.; Dalal, N.; Kasprzak, K S

    1994-01-01

    Electron spin resonance (ESR) spin trapping was utilized to investigate the generation of free radicals from oxidation of sodium sulfite, nickel(II) sulfite, and nickel subsulfide (Ni3S2) by ambient oxygen or H2O2 at pH 7.4. The spin trap used was 5,5-dimethyl-1-pyrroline-N-oxide (DMPO). Under ambient oxygen, a solution of sodium sulfite alone generated predominantly sulfur trioxide anion radical (.SO3-) due to the autoxidation of sulfite. Addition of nickel(II) chloride [Ni(II)] enhanced the...

  19. Avoiding total reduced sulfur (TRS) emissions from sodium sulfite pulping recovery processes

    This paper reports that one of the current trends in paper-making with cellulose pulping is the use of high-yield processes. With yields greater than 65%, these processes include mechanical pulps (groundwood and thermomechanical pulps or TMP), and semichemical types (chemi-TMP or CTMP). Groundwood and TMP make up about 10% of North American pulp production. Semichemical pulp makes up about 7% and is mostly used for corrugating medium. High-yield pulping for linerboard, particularly using the alkaline sulfite process, is also likely to be used in the future. High-yield pulping is based primarily on the sulfite process using mostly sodium-based chemicals. A disadvantage of this process is the unavailability of a recovery system for the inorganic pulping chemicals. Generally, mills have not accepted any particular recovery system for this process. For this and other reasons, sulfite processes constitute only 3-4% of the total North American pulp production. If high-yield processes continue to increase in popularity, a sodium sulfite chemical recovery system will be needed. A number of chemical recovery systems have been developed in the past 30 years for sodium-based sulfite pulping processes, with most of the mills successfully using this process located in Scandinavia

  20. Sulfite determination by a biosensor based on bay leaf tissue homogenate: very simple and economical method.

    Teke, Mustafa; Sezgintürk, Mustafa Kemal; Dinçkaya, Erhan

    2009-01-01

    Of all the food additives for which the FDA has received adverse reaction reports, the ones that most closely resemble true allergens are sulfur-based preservatives. Sulfites are used primarily as antioxidants to prevent or reduce discoloration of light-colored fruits and vegetables, such as dried apples and potatoes, and to inhibit the growth of microorganisms in fermented foods such as wine. This work aims to prepare an electrochemical biosensor based on bay leaf tissue homogenate that contains polyphenol oxidase enzyme abundantly for sulfite detection in foods. The principle of the biosensor is based on the inhibition effect of sulfites on polyphenol oxidase in the bioactive layer. Optimum conditions for the biosensor, such as temperature and pH, were investigated. Some stability parameters of the biosensor were also identified. The biosensor showed a linear calibration graph in the range of 25-100 microM sulfite. The biosensor presents a very simple, economical, reliable, and feasible method for sulfite detection in foods. PMID:19418312

  1. Determination of sulfite in foods and beverages by ion exclusion chromatography with electrochemical detection: collaborative study.

    Kim, H J

    1990-01-01

    A liquid chromatographic (LC) method for determination of total sulfite in foods and beverages by alkali extraction followed by ion exclusion chromatographic separation and electrochemical detection (IEC-EC) was collaboratively studied by 9 laboratories. Blind duplicate samples of starch, diluted lemon juice, wine cooler, dehydrated seafood, and instant mashed potatoes were analyzed without spiking and with added sulfite at 2 levels. The initial sulfite levels varied from 0 to 384 ppm SO2, and the levels added varied from 10 to 400 ppm. The initial sulfite levels determined by the IEC-EC method and the Monier-Williams method were in good agreement. Recovery of added sulfite by the IEC-EC method was generally higher than that by the Monier-Williams method. Within-laboratory repeatability (RSDr) for the IEC-EC method varied from 4.4 to 26.0%, and overall reproducibility (RSDR) varied from 8.5 to 39.3%. The collaborators found the method to be fast, sensitive, and easy to use, which makes it a useful alternative to the Monier-Williams method. The method has been adopted official first action. PMID:2324032

  2. Value-Added Products from FGD Sulfite-Rich Scrubber Materials

    Vivak Malhotra

    2010-01-31

    According to the American Coal Ash Association, about 29.25 million tons of flue gas desulfurization (FGD) byproducts were produced in the USA in 2003. Out of 29.25 million tons, 17.35 million tons were sulfite-rich scrubber materials. At present, unlike its cousin FGD gypsum, the prospect for effective utilization of sulfite-rich scrubber materials is not bright. In fact, almost 16.9 million tons are leftover every year. In our pursuit to mitigate the liability of sulfite-rich FGD scrubber materials' disposal, we are attempting to develop value-added products that can commercially compete. More specifically, for this Innovative Concept Phase I project, we have the following objectives: to characterize the sulfite-rich scrubber material for toxic metals; to optimize the co-blending and processing of scrubber material and natural byproducts; to formulate and develop structural composites from sulfite-rich scrubber material; and to evaluate the composites' mechanical properties and compare them with current products on the market. After successfully demonstrating the viability of our research, a more comprehensive approach will be proposed to take these value-added materials to fruition.

  3. Genome shuffling of Saccharomyces cerevisiae through recursive population mating to evolve tolerance to inhibitors of Spent Sulfite Liquor

    Martin, V.J.J.; Pinel, D.J.; D' aoust, F. [Concordia Univ., Montreal, PQ (Canada). Dept. of Biological Sciences; Bajwa, P.K.; Trevors, J.T.; Lee, H. [Guelph Univ., ON (Canada). Dept. of Environmental Biology

    2009-07-01

    The biochemical steps in the conversion of cellulosics to biofuels include the pretreatment, hydrolysis and fermentation of substrates into a final product. Fermentation of lignocellulosic substrates derived from waste biomass requires metabolic engineering. A biochemical flow chart from the Tembec Biorefinery plant was presented in which Spent Sulfite Liquor (SSL) was used to add value to the pulp and paper industry. The sugars contained in this carbohydrate-rich effluent from sulfite pulping were used to produce ethanol. A robust, ethanologenic microorganism that can withstand the substrate toxicity was needed. Saccharomyces cerevisiae is currently used for the production of ethanol from SSL. This yeast will succumb to toxicity and inhibition, particularly in the most inhibitor rich forms of SSL such as hardwood SSL (HWSSL). A genome shuffling method was therefore developed to create a better SSL fermenting strain. This method was designed to improve polygenic traits by generating pools of mutants with improved phenotypes, followed by iterative recombination between their genomes. Through 5 rounds of recursive mating and screening, 3 strains that could survive and grow in undiluted HWSSL were obtained. The study demonstrated that the tolerance of these strains to SSL translates into an increased capacity to produce ethanol over time using this substrate, due to continued viability of the yeast population. Phenotypic analysis of the three strains revealed that the genome shuffling approach successfully co-evolved tolerance to acetic acid, NaCl (osmotic) and HMF. A systems biology analysis of strain R57 was initiated in order to establish the genetic basis for HWSSL tolerance. tabs., figs.

  4. Hydrothermal Conversion of Neutral Sulfite Semi-Chemical Red Liquor into Hydrochar

    Ramy Gamgoum

    2016-06-01

    Full Text Available Hydrochar was produced from neutral sulfite semi-chemical (NSSC red liquor as a possible bio-based solid fuel for use in power generation facilities. Hydrothermal conversion (HTC experiments were conducted using a fixed liquor-to-water volume ratio of 1:8 and reaction time of 3 h. Solutions were processed using different chemical additives, pH and temperature conditions to determine the optimum conditions required for producing a high energy content solid fuel. The hydrochar samples produced were analyzed by ultimate, thermogravimetric (TGA and Fourier transform infrared spectroscopy (FTIR analyses to determine physicochemical properties that are important for utilization as a fuel. The residual process liquids were also analyzed to better understand the effect of HTC process conditions on their properties. It was determined that the optimum conditions for producing a solid fuel was at a reaction temperature of 250 °C, in the presence of acetic acid at pH 3. The maximum energy content (HHV of the hydrochar produced from red liquor at this condition was 29.87 MJ/kg, and its ash content was 1.12 wt.%. This result reflects the effect of increasing reaction temperature on the physicochemical characteristics of the hydrochar. The increase of HTC temperature significantly reduces the ash content of the hydrochar, leads to a significant increase in the carbon content of the hydrochar, and a reduction in both the oxygen and hydrogen content. These effects suggests an increase in the degree of condensation of the hydrochar products, and consequently the formation of a high energy content material. Based on TGA and FTIR analyses, hydrochars prepared at high HTC temperature showed lower adsorbed moisture, hemicellulose and cellulose contents, with enrichment in content of higher temperature volatiles, such as lignin.

  5. Simple Method for Simultaneous Determination of Carbonate, Sulfite and Hydroxide in Solution

    Hossam I. Al-Itawi; Hamdan Al-Ebaisat; Mazen Al-Garaleh

    2007-01-01

    A method is proposed for the simultaneous determination of carbon dioxide and sulphur dioxide in a complex matrices. The method involves salvation of the tow gases in Sodium Hydroxide solution followed by simultaneous determination of the three species (carbonate, sulfite and hydroxide) using conductometric and potentiometric titration. What set this method apart from other determination methods it`s simplicity.

  6. New crystalline phases from crystallographic thermal and microscopic studies of alkaline earth sulfites

    Different crystalline phases of sulfites of calcium, strontium and barium were obtained by several synthetic methods and under different crystallization conditions. The crystal structures of these products were determined by means of chemical, thermogravimetric, thermodifferential and X-ray powder diffraction analyses, microscopic observation and solubility determinations in aqueous electrolyte solutions. (H.K.)

  7. Capillary electrophoretic determination of sulfite using the zone-passing technique of in-capillary derivatization.

    Jankovskiene, G; Daunoravicius, Z; Padarauskas, A

    2001-11-16

    A new capillary electrophoretic (CE) method was developed for the simple and selective determination of sulfite. The proposed method is based on the in-capillary derivatization of sulfite with iodine using the zone-passing technique and direct UV detection of iodide formed. The optimal conditions for the separation and derivatization reaction were established by varying concentration of iodine, electrolyte pH and applied voltage. The optimised separations were carried out in 20 mmol l(-1) Tris-HCl electrolyte (pH 8.5) using direct UV detection at 214 nm. Experimental results showed that the injection of the iodine zone from anodic end of the capillary gives significantly better precision. Common UV absorbing anions such as Br-, l-, S2O3(2-), NO3-, NO2-, SCN- did not give any interferences. Valid calibration (r2=0.998) is demonstrated in the range 1 x 10(-5) - 8 x 10(-4) mol l(-1) of sulfite. The detection limit (SIN=3) was 2 x 10(-6) mol l(-1). The proposed system was applied to the determination of free sulfite in wines. The recovery tests established for wine samples were within the range 92-103%. The CE results were compared with those obtained by iodometric titration technique. PMID:11762765

  8. Survey of sulfites in wine and various Turkish food and food products intended for export, 2007-2010.

    Ulca, P; Öztürk, Y; Senyuva, H Z

    2011-01-01

    Surveys were carried out between 2007 and 2010 to determine the total levels of sulfites in 1245 samples of wines, dried apricots, dried vegetables, nuts, juices and purees, frozen foods and cereals containing dried fruit supplied by food inspectors and by food producers for testing or for export certification. Sulfite analysis of wine was carried out using the Ripper method with an LOQ of 5 mg l(-1) and for dried and other foods the Monier-Williams distillation procedure was employed with an LOQ of 10 mg kg(-1). In the survey all wines contained measurable sulfites, but with the exception of one sample of white wine they were otherwise below Turkish Food Codex limits of 160 mg kg(-1) for red wine, 210 mg kg(-1) to white wine and 235 mg kg(-1) for sparkling wine. None of the cereal products, frozen foods, juices or purees contained sulfites above 10 mg kg(-1). However, all dried apricot samples contained significant levels of sulfite with around 40% having levels exceeding the Turkish limit of 2000 mg kg(-1). Significant levels of sulfite were found in other samples of dried fruit with even a fruit and nut bar containing 1395 mg kg(-1) of sulfite, suggesting the dried fruit ingredients contained levels above regulatory limits. PMID:24786011

  9. Silver nanoparticles synthesis in aqueous solutions using sulfite as reducing agent and sodium dodecyl sulfate as stabilizer

    The synthesis of silver nanoparticles has been carried out in aqueous solutions in a stirred semibatch reactor through the reduction of silver ions (Ag+) by sulfite ions (SO32−), which were added at a tightly controlled rate up to a final sulfite/silver molar ratio of 0.45. Sodium dodecyl sulfate (SDS) was used as the stabilizer at concentrations below its critical micelle concentration. The effects of temperature, sulfite addition rate, and SDS concentration have been assessed. Ag+ turned to Ag0 in 5 min or less only when the synthesis was performed at 97 °C and not below. The sulfite addition rates studied were 0.5, 7.5, 15, and 90 μmol/min. The size, shape, polydispersity, and stability of the nanoparticles were determined by the sulfite addition rate and SDS concentration. At low SDS concentration (4 mM), stable, spherical shape, small size nanoparticles were formed only at the two intermediate sulfite addition rates. At the highest sulfite addition rate, 9 nm mean size spherical nanoparticles having a low ±5 nm polydispersity were produced at a high SDS concentration of 10 mM. With the low SDS concentration, larger truncated and spherical shape nanoparticles were obtained. UV–Vis spectrophotometry and transmission electron microscopy were used to characterize the nanoparticles.

  10. Value-Added Products From FGD Sulfite-Rich Scrubber Materials

    Vivak M. Malhotra

    2006-09-30

    Massive quantities of sulfite-rich flue gas desulfurization (FGD) scrubber materials are produced every year in the USA. In fact, at present, the production of wet sulfite-rich scrubber cake outstrips the production of wet sulfate-rich scrubber cake by about 6 million tons per year. However, most of the utilization focus has centered on FGD gypsum. Therefore, we have recently initiated research on developing new strategies for the economical, but environmentally-sound, utilization of sulfite-rich scrubber material. In this exploratory project (Phase I), we attempted to ascertain whether it is feasible to develop reconstituted wood replacement products from sulfite-rich scrubber material. In pursuit of this goal, we characterized two different wet sulfite-rich scrubber materials, obtained from two power plants burning Midwestern coal, for their suitability for the development of value-added products. The overall strategy adopted was to fabricate composites where the largest ingredient was scrubber material with additional crop materials as additives. Our results suggested that it may be feasible to develop composites with flexural strength as high as 40 MPa (5800 psi) without the addition of external polymers. We also attempted to develop load-bearing composites from scrubber material, natural fibers, and phenolic polymer. The polymer-to-solid ratio was limited to {le} 0.4. The formulated composites showed flexural strengths as high as 73 MPa (10,585 psi). We plan to harness the research outcomes from Phase I to develop parameters required to upscale our value-added products in Phase II.

  11. Development of an amperometric sulfite biosensor based on SO(x)/PBNPs/PPY modified ITO electrode.

    Rawal, Rachna; Pundir, C S

    2012-11-01

    A sulfite oxidase (SO(x)) (EC 1.8.3.1) purified from Syzygium cumini leaves was immobilized onto prussian blue nanoparticles/polypyrrole composite (PBNPs/PPY) electrodeposited onto the surface of indium tin oxide (ITO) electrode. An amperometric sulfite biosensor was fabricated using SO(x)/PBNPs/PPY/ITO electrode as working electrode, Ag/AgCl as standard and Pt wire as auxiliary electrode connected through a potentiostat. The working electrode was characterized by Fourier transform infrared (FTIR) spectroscopy, cyclic voltammetry (CV), scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS) before and after immobilization of SO(x). The biosensor showed optimum response within 2s, when operated at 20 mV s⁻¹ in 0.1M Tris-HCl buffer, pH 8.5 and at 35 °C. Linear range and minimum detection limit were 0.5-1000 μM and 0.12 μM (S/N=3) respectively. There was good correlation (r=0.99) between red wine samples sulfite value by standard DTNB method and the present method. The sensor was evaluated with 97% recovery of added sulfite in red wine samples and 2.2% and 4.3% within and between batch coefficients of variation respectively. The sensor was employed for determination of sulfite level in red and white wine samples. The enzyme electrode was used 200 times over a period of 3 months when stored at 4 °C. PMID:22705572

  12. Rapid flow injection method for the determination of sulfite in wine using the permanganate-luminol luminescence system.

    Navarrro, Mercedes Villar; Payán, María Ramos; López, Miguel Angel Bello; Fernández-Torres, Rut; Mochón, Manuel Callejón

    2010-10-15

    A simple, rapid and sensitive chemiluminescence method for the determination of sulfite has been developed by combining flow-injection analysis and its sensitizing effect on the known chemiluminescence emission produced by the oxidation of luminol in alkaline medium; in this work permanganate has been proposed as oxidizing reactive. The optimum conditions for the chemiluminescence emission were established. The chemiluminescence was proportional to the sulfite concentration over the range 1.6 × 10(-5) and 4.0 × 10(-4)mol L(-1). The detection limit was 4.7 × 10(-6)mol L(-1) of sulfite. The method has been satisfactorily used for the determination of free and bound sulfite in wines. PMID:20875609

  13. Combined effects of sulfites, temperature, and agitation time on production of glycerol in grape juice by Saccharomyces cerevisiae.

    Gardner, N; Rodrigue, N; Champagne, C P

    1993-07-01

    Analysis of variance was used to evaluate the simultaneous effects of strain, incubation temperature (15 to 25 degrees C), agitation time (0 to 24 h), and initial sulfite concentration (100 to 300 ppm) on glycerol production in grape juice by Saccharomyces cerevisiae. Fourteen strains were studied to determine their growth patterns in the presence of sulfites and ethanol. Baker's yeast strains were more sensitive to sulfite than wine strains, and little growth occurred at initial sulfite levels greater than 150 ppm. Sensitivity to sulfite increased with increasing levels of ethanol. Three strains exhibiting the best growth in the presence of sulfites and ethanol were selected for interaction studies. Fermentations were carried out until the solids content had decreased to less than 6 degrees Brix, which was the point that glycerol content became stable. For the three strains used, the greatest level of glycerol production was observed in the presence of 300 ppm of sulfite for most incubation temperatures and agitation times. There was significant interaction between the strain, incubation temperature, and agitation time parameters for glycerol synthesis, and a response surface method was used to predict the optimal conditions for glycerol production. Under static conditions, the highest level of glycerol production was observed at 20 degrees C, while incubation at 25 degrees C gave the best results when the cultures were agitated for 24 h. Response surface equations were used to predict that the optimum conditions for glycerol production by S. cerevisiae Y11 were a temperature of 22 degrees C, an initial sulfite concentration of 300 ppm, and no agitation, which yielded 0.68 g of glycerol per 100 ml. PMID:8357243

  14. Pattern formation in the thiourea-iodate-sulfite system: Spatial bistability, waves, and stationary patterns

    Horváth, Judit; Szalai, István; De Kepper, Patrick

    2010-06-01

    We present a detailed study of the reaction-diffusion patterns observed in the thiourea-iodate-sulfite (TuIS) reaction, operated in open one-side-fed reactors. Besides spatial bistability and spatio-temporal oscillatory dynamics, this proton autoactivated reaction shows stationary patterns, as a result of two back-to-back Turing bifurcations, in the presence of a low-mobility proton binding agent (sodium polyacrylate). This is the third aqueous solution system to produce stationary patterns and the second to do this through a Turing bifurcation. The stationary pattern forming capacities of the reaction are explored through a systematic design method, which is applicable to other bistable and oscillatory reactions. The spatio-temporal dynamics of this reaction is compared with that of the previous ferrocyanide-iodate-sulfite mixed Landolt system.

  15. Electrodeposition of gold from formaldehyde-sulfite baths: bath stability and deposits characterization

    Juliana L. Cardoso; Sebastião G. dos Santos Filho

    2011-01-01

    It was investigated Au(I)-sulfite baths containing formaldehyde. As a result, high stability was achieved for baths containing formaldehyde concentration close to 10 mL L-1 with a lifetime superior to 600 days. On the other hand, cyclic voltammograms indicated that the increase of formaldehyde concentration in the bath promotes decreasing of the maximum cathodic current, so that, if the formaldehyde concentration is high, the surface areal concentration of gold will be low. Also, the lowest s...

  16. Determination of total sulfite in shrimp with rapid steam distillation methods

    Vyncke, W.

    1993-01-01

    The efficiency of two types of steam distillation apparatus viz. a rapid distillation unit (Tecator) and a compact distillation apparatus according to Antonacopoulos vas evaluated, using either iodimetric titration or colorimetric determination with Ellman's reagent. There was no interference from the shrimp matrix. Recoveries of sulfite added to shrimp averaged 99,6% (s = 3,8%) for concentrations of at least 3 µg/g with Tecator and 10 /µg/g with Antonacopoulos. Best results were obtained wit...

  17. [Determination of total sulfite in wine by high performance liquid chromatography(HPLC) with fluorescence detection].

    Wei, F; Chen, M S; Yu, L; Chang, L; Li, D M

    1999-11-01

    A highly sensitive fluorometric method for the determination of total sulfite in wine is reported. The strong fluorescent derivatives formed by the quantitative reaction of sulfite in wine and N-(9-acridinyl) maleimide(NAM) in aqueous solution under mild conditions was injected into the HPLC. Separation was performed on an ODS column(200 mm x 5 mm) with a mobile phase of V(CH3CN):V(0.1 mo/L NH4AC) = 25:75 at a flow rate of 1.0 mL/min and detected by fluorometry at 455 nm(excitation at 365 nm). There was a good linear calibration curve in the range from 0.25-4 mg/L(r = 0.9998), The limit of detection was 1 ng. Sulfite mass concentration in wine has been determined by this method with good results and recoveries. This method is simple, rapid and reliable, and a sample size of only 1 mL is required to complete an analysis. PMID:12552699

  18. Usefulness of ytterbium(III) as analytical reagent for total sulfite determination in white wine samples.

    Rodríguez-Díaz, Rafael Carlos; Aguilar-Caballos, Maria Paz; Gómez-Hens, Agustina

    2004-12-29

    Ytterbium(III) is used as reagent for the determination of sulfite by measuring the formation of the Yb(III)-sulfite complex through the variation of the light scattering intensity with time. The low solubility of this complex causes an efficient dispersion of the radiation at 490 nm, which is measured at 980 nm. Each kinetic datum is automatically obtained in only 0.5 s by stopped-flow mixing technique. The application of the initial rate method using a long emission wavelength minimizes the potential interference of fluorescent background signals from the sample matrix. The dynamic range of the calibration graph is 1-250 microg/mL, and the calculated detection limit is 0.35 microg/mL. The precision, expressed as relative standard deviation, is determination of total sulfites in white wine samples, which requires only the sample dilution and the use of two aliquots to improve selectivity. However, the matrix effect found for red wines precludes the application of the method to the direct analysis of these samples. Analytical recoveries ranged from 96.0 to 106.7%. The results obtained with the proposed method agreed with those provided by the p-rosaniline method. Unlike this method, in which toxic reagents are required, the use of ytterbium(III) as analytical reagent shows the advantage of its low acute toxic rating. PMID:15612754

  19. Chemical and physical properties of high-yield alkaline sulfite green liquor

    Sell, N.J.; Norman, J.C. (Univ. of Wisconsin, Green Bay, WI (United States). Natural and Applied Sciences)

    1993-11-01

    The majority of sodium sulfite pulping liquor recovery systems are based on the reductive burning of the spent liquor, followed by acidification of the resulting smelt solution by CO[sub 2]. This study investigated a number of the physical and chemical properties of the resulting green liquor which might be relevant to the optimum design of this type of sulfite and carbonate recovery system for an alkaline sulfite high-yield process. CO[sub 2] gas does generate H[sub 2]S when bubbled through green liquor; however, a large amount of solid soon is formed. Continuing the flow leads to increased amounts of H[sub 2]S, but the ratio of H[sub 2]S to CO[sub 2] remains less than 1.0. Solutions more highly concentrated in Na[sub 2]S absorb relatively more CO[sub 2], regardless of the ratios of H[sub 2]S to CO[sub 2] in the initial gas stream. The percentage of H[sub 2]S released increases with increasing Na[sub 2]S concentration. Stripping the green liquor with inert gas, steam, or vacuum does not improve the H[sub 2]S removal efficiency. The maximum CO[sub 2] pressure can be generated by decomposing pure 6 M NaHCO[sub 3]. If the starting material is a bicarbonate/carbonate mixture, conversion is incomplete and a portion of the NaHCO[sub 3] forms a dead load.

  20. Influence of the enzyme dissimilatory sulfite reductase on stable isotope fractionation during sulfate reduction

    Mangalo, Muna; Einsiedl, Florian; Meckenstock, Rainer U.; Stichler, Willibald

    2008-03-01

    The stable isotopes of sulfate are often used as a tool to assess bacterial sulfate reduction on the macro scale. However, the mechanisms of stable isotope fractionation of sulfur and oxygen at the enzymatic level are not yet fully understood. In batch experiments with water enriched in 18O we investigated the effect of different nitrite concentrations on sulfur isotope fractionation by Desulfovibrio desulfuricans. With increasing nitrite concentrations, we found sulfur isotope enrichment factors ranging from -11.2 ± 1.8‰ to -22.5 ± 3.2‰. Furthermore, the δ18O values in the remaining sulfate increased from approximately 50-120‰ when 18O-enriched water was supplied. Since 18O-exchange with ambient water does not take place in sulfate, but rather in intermediates of the sulfate reduction pathway (e.g. SO32-), we suggest that nitrite affects the steady-state concentration and the extent of reoxidation of the metabolic intermediate sulfite to sulfate during sulfate reduction. Given that nitrite is known to inhibit the production of the enzyme dissimilatory sulfite reductase, our results suggest that the activity of the dissimilatory sulfite reductase regulates the kinetic isotope fractionation of sulfur and oxygen during bacterial sulfate reduction. Our novel results also imply that isotope fractionation during bacterial sulfate reduction strongly depends on the cell internal enzymatic regulation rather than on the physico-chemical features of the individual enzymes.

  1. Determination of total sulfite in shrimp, potatoes, dried pineapple, and white wine by flow injection analysis: collaborative study.

    Sullivan, J J; Hollingworth, T A; Wekell, M M; Meo, V A; Saba, H H; Etemad-Moghadam, A; Eklund, C; Phillips, J G; Gump, B H

    1990-01-01

    A method for the determination of total sulfite in shrimp, potatoes, dried pineapple, and white wine by flow injection analysis (FIA) was collaboratively studied by 8 laboratories. In the method, the sample solution is reacted with sodium hydroxide to liberate aldehyde-bound sulfite. The sample stream is acidified to produce SO2 gas, which diffuses across a Teflon membrane in the gas diffusion cell into a flowing stream of malachite green. The degree of discoloration of the malachite green is proportional to the amount of sulfite in the sample solution. Red wine was included in the study but interlaboratory precision for these samples was not satisfactory and correlation with Monier-Williams results was poor. The present method is not recommended for use with these samples. For shrimp, potatoes, dried pineapple, and white wine, average reproducibility (RSDR) of results was 25% for samples at 10 ppm SO2 and 10% for samples at greater than 50 ppm. Overall average reproducibility was 14%. Recoveries of sulfite added to samples averaged 80%. Comparison of FIA with the Monier-Williams method indicated comparable results by the 2 methods. The FIA method has been adopted official first action for determination of greater than or equal to 5 ppm total sulfite in shrimp, potatoes, dried pineapple, and white wine. PMID:2312511

  2. Effects of the methyltrimethoxysilane coupling agent on phenolic and miscanthus composites containing calcium sulfite scrubber material

    Jones, Sean

    The purpose of this research is to test the effects of methyltrimethoxysilane coupling agent on composite material containing calcium sulfite obtained from the Southern Illinois Power Co-operative. This scrubber material and the miscanthus plant are of interest due to their use in coal burning power plants to reduce toxic emission. When calcium sulfate is passed through coal fire gas emissions it absorbs mercury and sulfur. In these composites it is used as filler to reduce cost. Miscanthus is a source of both cellulose reinforcement and some natural resin. This plant has low care requirements, little mineral content, useful energy return, and positive environmental effects. Under investigation is whether a post-cure procedure or a silane coupling agent will positively impact the composite. Hot pressing alone may not be enough to fully cure the phenolic. It is hoped that the silane will increase the strength characteristics of the composite by enhancing adhesion between the calcium sulfite and phenolic resin. Possible effects on the miscanthus by the silane will also be tested. Phenolic is being utilized because of its recycling and biodegradable properties along with cost effectiveness in mass production. Composite mechanical performance was measured through 3-point bending to measure flexural strength and strain at breakage. A dynamic mechanical analyzer (DMA) was used to find thermomechanical properties. The post-cure was found to be effective, particularly on the final composite containing silane. When methyltrimethoxysilane was added to the miscanthus prior to fabrication, it was found to reduce flexural strength and density. However the addition of methyltrimethoxysilane to the calcium sulfite altered thermo-mechanical properties to a state more like pure phenolic, with added flexibility and thermal stability.

  3. 21 CFR Appendix A to Part 101 - Monier-Williams Procedure (With Modifications) for Sulfites in Food, Center for Food Safety and...

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Monier-Williams Procedure (With Modifications) for Sulfites in Food, Center for Food Safety and Applied Nutrition, Food and Drug Administration (November 1985...-Williams Procedure (With Modifications) for Sulfites in Food, Center for Food Safety and Applied...

  4. Studies on the Iron-Sulfur clusters of hydrogenase, sulfite reductase, nitrogenase and the prismane protein.

    Pierik, A.J.

    1993-01-01

    Iron-sulfur clusters are present in a large number of proteins. Sofar structures of four types of protein-bound iron-sulfur clusters have been determined by X-ray diffraction: rubredoxin-like, [2Fe-2S], [3Fe-4S] and [4Fe-4S] centers. The presence of any of these clusters in a protein can be predicted by comparison of spectroscopic properties. However a number of multiple-electron transferring enzymes, like the Fe-only hydrogenase, sulfite reductase and nitrogenase MoFe protein have enigmatic ...

  5. Bis(indolyl)methanes synthesis through sodium iodate and sodium hydrogen sulfite in water

    An effective and eco-friendly method for the bis(indolyl)methanes synthesis has been developed. A successive methodology involving sodium iodate/sodium hydrogen sulfite catalyzed reaction of indole with many aldehydes gave the resultant bis-indol in good yield. This method offers synthetically inexpensive alternate to the previously developed procedures for the bis-indol synthesis. The use of a low-cost and straightforwardly accessible catalyst, improved yields and a simple reaction process are the salient features of the current method. (author)

  6. Effect of sulfites on the in vitro antioxidant activity of wines

    C.D. Di Mattia; A. PIVA; M. Martuscelli; D. Mastrocola; G. Sacchetti

    2015-01-01

    The objective of this study was to assess the contribution of SO2 to the overall antioxidant activity of wines. In this study, white, red, and model wines, with increasing sulfite content, were used.The radical scavenging activity of the wines was evaluated by ABTS and DPPH assays, while the reducing capacity of the wines was assessed by the FRAP assay. SO2 positively affected the antioxidant properties of the wines and, in some cases, its contribution to the overall antioxidant activity of w...

  7. An electrochemical approach: Switching Structures of rare earth metal Praseodymium hexacyanoferrate and its application to sulfite sensor in Red Wine

    Graphical abstract: Nucleation and growth of PrHCF and its application to sulfite oxidation in wine samples. - Highlights: • Electrochemical synthesis of PrHCF. • Switching structures of PrHCF. • Sulfite electrochemical sensor. • Wide linear range and low limit of detection. • Real sample application. - Abstract: Herein, we report a shape-controlled preparation of Praseodymium hexacyanoferrate (PrHCF) using a simple electrochemical technique. The electrochemically fabricated PrHCF modified glassy carbon electrodes (GCE) shows an excellent electrocatalytic activity towards sulfite oxidation. The morphology of PrHCF particles were controlled by carefully changing various synthesis conditions including electrochemical technique (cyclic voltammetry, amperometry and chemical), cations in the supporting electrolyte (K+, Na+, Li+ and H+), deposition cycles, molar ratio of precursors, and applied potential (-.2,0 and 0.2 V). The morphologies of the PrHCF was elucidated using scanning electron microscopy (SEM). The as-synthesized PrHCF was characterized using X-ray diffraction pattern (XRD), Infra-red (IR) and energy dispersive X-ray spectroscopy (EDX). The electrochemical oxidation of sulfite on PrHCF modified GCE was investigated using cyclic voltammetry (CV) and linear sweep voltammetry (LSV). The sensitivity of the as-developed sulfite sensor was determined to be 0.036 μA μM−1 cm−2. The low limit of detection was determined to be 2.15 μM. The real time application of PrHCF modified GCE was confirmed through the determination of sulfite from red wine and tap water samples

  8. Investigating the potential of thermophilic species for ethanol production from industrial spent sulfite liquor

    Michaela Weissgram

    2015-10-01

    Full Text Available Thermophilic microorganisms hold a great potential for bioethanol production on waste biomass, due to their ability to utilize pentoses and hexoses alike. However, to date hardly any data on thermophiles growing directly on industrial substrates like spent sulfite liquor (SSL are available. This contribution investigates the ability of Thermoanaerobacter species to utilize the main sugars in the used SSL (mannose, glucose and xylose and the effect of process parameters (pH, temperature and sugar concentration on their growth. Based on these results the strain T. mathranii was chosen for further studies. The ability of T. mathranii to grow directly on SSL was investigated and the effect of several inhibiting substances on growth was elucidated. Furthermore it was tested whether pretreatment with activated charcoal can increase the fermentability of SSL. The fermentations were evaluated based on yields and specific rates. It could be shown that T. mathranii was able to ferment all sugars in the investigated softwood SSL and fermented diluted, untreated SSL (up to 2.7% (w/w dry matter. Pretreatment with activated charcoal could slightly reduce the amount of phenols in the substrate and thus facilitate growth and ethanol production on higher SSL concentrations (up to 4.7% (w/v dry matter. Ethanol yields of 0.29-0.44 Cmmol of ethanol per Cmmol sugar were obtained on untreated and pretreated spent sulfite liquor, respectively. These results on an industrial substrate strengthen the claim that thermophilic microorganisms might be the optimal candidates for forest biorefinery.

  9. Redox states of Desulfovibrio vulgaris DsrC, a key protein in dissimilatory sulfite reduction

    Venceslau, Sofia S. [Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras (Portugal); Cort, John R.; Baker, Erin S. [Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Chu, Rosalie K.; Robinson, Errol W. [Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Dahl, Christiane [Institut für Mikrobiologie and Biotechnologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Meckenheimer Allee 168, D-53115 Bonn (Germany); Saraiva, Lígia M. [Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras (Portugal); Pereira, Inês A.C., E-mail: ipereira@itqb.unl.pt [Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras (Portugal)

    2013-11-29

    Highlights: •DsrC is known to interact with the dissimilatory sulfite reductase enzyme (DsrAB). •We show that, however, most cellular DsrC is not associated with DsrAB. •A gel-shift assay was developed that allows monitoring of the DsrC redox state. •The DsrC intramolecularly oxidized state could only be produced by arginine treatment. -- Abstract: Dissimilatory reduction of sulfite is carried out by the siroheme enzyme DsrAB, with the involvement of the protein DsrC, which has two conserved redox-active cysteines. DsrC was initially believed to be a third subunit of DsrAB. Here, we report a study of the distribution of DsrC in cell extracts to show that, in the model sulfate reducer Desulfovibrio vulgaris, the majority of DsrC is not associated with DsrAB and is thus free to interact with other proteins. In addition, we developed a cysteine-labelling gel-shift assay to monitor the DsrC redox state and behaviour, and procedures to produce the different redox forms. The oxidized state of DsrC with an intramolecular disulfide bond, which is proposed to be a key metabolic intermediate, could be successfully produced for the first time by treatment with arginine.

  10. Detection of sewage organic chlorination products that are resistant to dechlorination with sulfite

    MacCrehan, W.A. [National Inst. of Standards and Technology, Gaithersburg, MD (United States). Analytical Chemistry Div.; Jensen, J.S.; Helz, G.R. [Univ. of Maryland, College Park, MD (United States). Dept. of Chemistry and Biochemistry

    1998-11-15

    Most of the 36 billion gal of treated sewage wastewater discharged daily into the environment in the United States is disinfected via chlorination. To minimize toxicity. dechlorination with sulfite or sulfur dioxide is often performed. Although dechlorination is considered instantaneous and complete, several studies have found residual toxicity of chlorinated/dechlorinated effluent to aquatic life. The authors investigated chlorination/dechlorination of the organic nitrogen components of sewage wastewater using both iodometric titration and a novel LC method. For LC, a postcolumn reaction with iodide rendered submicromolar chloramine concentrations detectable with amperometry. Using a gradient-elution LC separation, the retention and dechlorination behavior of a suite of model amines was determined, representing primary and secondary aliphatic, peptide, and protein-N. Chlorination/dechlorination experiments on freshly collected, tertiary-treated wastewater showed a fraction of the organic N-chloramines are dechlorinated slowly by sulfite with half-lives of >20 min. Chromatographic retention and kinetic behavior of the sewage N-chloramines was consistent with the behavior of the model peptides and proteins. Proteolytic hydrolysis markedly increased the peptide fraction observed upon chlorination of the wastewater. These results suggest that peptides and proteins contribute to slow dechlorination of sewage and may be a factor in the toxicity noted for chlorine-disinfected wastewater.

  11. Determination of free and reversibly-bound sulfite in selected foods by high-performance liquid chromatography with fluorometric detection.

    Chung, Stephen Wai Cheung; Chan, Benny T P; Chan, Andy C M

    2008-01-01

    A rapid and accurate method for measuring low part-per-million levels of free and reversibly-bound sulfites in selected foods by using high-performance liquid chromatography (HPLC) with fluorometric detection was developed. Sulfites were extracted with sodium tetrachloromercurate solution and determined by HPLC-fluorescence spectrometry. During the HPLC analysis, the sample extract was reacted with sodium hydroxide to liberate the reversibly-bound sulfite and subsequently separated from other interferences by a size exclusion column. The effluent was then reacted with o-phthalaldehydelammonium chloride reagent to form a fluorescing 1-sulfonatoisoindole derivative and analyzed by a fluorescence detector. The method has been applied to a variety of foods and food products, with no significant interference encountered in matrixes such as soy products, cabbage, broccoli, brassica, ginger, fungus, mushroom, mandarin peel, potato chips, and biscuits. It was shown to have a broad linear range of 0.01 to 0.4 mg/L as SO2. The spike recoveries of sodium sulfite, sodium metabisulfite, and formaldehyde-sodium bisulfite adduct at the 5 to 10 mg/kg level in the tested food matrix were within 80-120%, and the limit of detection was 5 mg/kg. Laboratory of Government Chemist Reference Material LGC7111 (potato powder) was used to assess the accuracy of the method. The expanded measurement uncertainty of the method at 95% confidence level was estimated to be 17%. PMID:18376591

  12. Thiosulfate and Sulfite Distributions in Porewater of Marine-Sediments Related to Manganese, Iron, and Sulfur Geochemistry

    THAMDRUP, B.; FINSTER, K.; FOSSING, H.; HANSEN, JW; JØRGENSEN, BB

    1994-01-01

    Depth distributions of thiosulfate (S2O32-) and sulfite (SO32-) were measured in the porewaters of a Danish salt marsh and subtidal marine sediments by HPLC analysis after derivatization with DTNP [2,2'-dithiobis(5-nitropyridine)]. The distributions were compared to the redox zonation as indicate...

  13. Simple flow injection for determination of sulfite by amperometric detection using glassy carbon electrode modified with carbon nanotubes-PDDA-gold nanoparticles.

    Amatatongchai, Maliwan; Sroysee, Wongduan; Chairam, Sanoe; Nacapricha, Duangjai

    2015-02-01

    A new approach is presented for sensitive and selective measurement of sulfite (SO3(2-)) in beverages based on a simple flow injection system with amperometric detection. In this work, the sulfite sensor was a glassy carbon electrode modified with multiwall carbon nanotubes-poly(diallyldimethylammonium chloride)-gold nanoparticles composites (CNTs-PDDA-AuNPs/GC). Electrochemical oxidation of sulfite with this electrode was first studied in 0.1M phosphate buffer (pH 7.0) using cyclic voltammetry. The results indicated that the CNTs-PDDA-AuNPs/GC electrode possesses electrocatalytic activity for the oxidation of sulfite with high sensitivity and selectivity. Sulfite was quantified using amperometric measurement with the new sensor at +0.4V vs Ag/AgCl in conjunction with flow injection. The linear working range for the quantitation of sulfite was 2-200 mg L(-1) (r(2)=0.998) with a detection limit of 0.03 mg L(-1) (3σ of blank) and an estimated precision of 1.5%.The proposed method was successfully applied to the determination of sulfite in fruit juices and wines with a sample throughput of 23 samples per hour. PMID:25435239

  14. Determination of free sulfite in wine by zone electrophoresis with isotachophoresis sample pretreatment on a column-coupling chip.

    Masár, Marián; Danková, Mariana; Olvecká, Eva; Stachurová, Adela; Kaniansky, Dusan; Stanislawski, Bernd

    2004-02-13

    This work deals with the determination of free sulfite in wine by zone electrophoresis (ZE) with on-line isotachophoresis (ITP) sample pretreatment on a column-coupling (CC) chip with conductivity detection. A rapid pre-column conversion of sulfite to hydroxymethanesulfonate (HMS), to minimize oxidation losses of the analyte, was included into the developed analytical procedure, while ITP and ZE were responsible for specific analytical tasks in the separations performed on the CC chip. ITP, for example, eliminated the sample matrix from the separation compartment and, at the same time, provided a selective concentration of HMS before its transfer to the ZE stage of the separation. On the other hand, ZE served as a final separation (destacking) method and it was used under the separating conditions favoring a sensitive conductivity detection of HMS. In this way, ITP and ZE cooperatively contributed to a 900 microg/l concentration detectability for sulfite as attained for a 60 nl load of wine (a 15-fold wine dilution and the use of a 0.9 microl sample injection channel of the chip) and, consequently, to the determination of free sulfite when this was present in wine at the concentrations as low as 3 mg/l. The separations were carried out in a closed separation compartment of the chip with suppressed hydrodynamic and electroosmotic flows. Such transport conditions, minimizing fluctuations of the migration velocities of the separated constituents, made a frame for precise migration and quantitation data as achieved for HMS in both the model and wine samples. Ninety percent recoveries, as typically obtained for free sulfite in wine samples, indicate promising potentialities of the present method as far as the accuracies of the provided analytical results are concerned. PMID:14763730

  15. Comparative Study of SPORL and Dilute Acid Pretreatments of Spruce for Cellulosic Ethanol Production

    The performance of two pretreatment methods, Sulfite Pretreatment to Overcome Recalcitrance of Lignocellulose (SPORL) and Dilute Acid (DA), was compared in pretreating softwood (spruce) for fuel ethanol production under the same conditions of temperature (180°C), time (30 min), sulfuric acid loading...

  16. Treatment of the Bleaching Effluent from Sulfite Pulp Production by Ceramic Membrane Filtration

    Mehrdad Ebrahimi

    2015-12-01

    Full Text Available Pulp and paper waste water is one of the major sources of industrial water pollution. This study tested the suitability of ceramic tubular membrane technology as an alternative to conventional waste water treatment in the pulp and paper industry. In this context, in series batch and semi-batch membrane processes comprising microfiltration, ultrafiltration and nanofiltration, ceramic membranes were developed to reduce the chemical oxygen demand (COD and remove residual lignin from the effluent flow during sulfite pulp production. A comparison of the ceramic membranes in terms of separation efficiency and performance revealed that the two-stage process configuration with microfiltration followed by ultrafiltration was most suitable for the efficient treatment of the alkaline bleaching effluent tested herein, reducing the COD concentration and residual lignin levels by more than 35% and 70%, respectively.

  17. Anodic dissolution of gold in alkaline solutions containing thiourea, thiosulfate and sulfite ions

    2002-01-01

    Gold dissolves electrochemically in alkaline solutions containing ligands to form complex ions with gold ion. Therefore, selective leaching of noble metals is expected without dissolution of base metals such as steels, aluminum alloys in scrap treatment. Gold electrodes were investigated using linear sweep voltammetry, EQCM method and potentiostatic electrolysis in alkaline solutions containing thiourea, Na2SO3 and Na2S2O3. The solution composition, electrode potential affect gold dissolution rate and current efficiency. The gold dissolved from anode electrode forms complex ions, suspension particles as compound precipitates and deposits on cathode electrode as a metal. Anodic efficiency for gold dissolution is between 10% and 22%. This is caused by the oxidation decomposition of sulfite ions and thiourea. The stability of the alkaline solution containing these elements was also estimated by capillary electrophoresis technique.

  18. Sulfur globule oxidation in green sulfur bacteria is dependent on the dissimilatory sulfite reductase system

    Holkenbrink, Carina; Ocón Barbas, Santiago; Mellerup, Anders;

    2011-01-01

    Green sulfur bacteria oxidize sulfide and thiosulfate to sulfate with extracellular globules of elemental sulfur as intermediate. Here we investigated which genes are involved in the formation and consumption of these sulfur globules in the green sulfur bacterium Chlorobaculum tepidum. We show that...... sulfur globule oxidation is strictly dependent on the dissimilatory sulfite reductase (DSR) system. Deletion of dsrM/CT2244 or dsrT/CT2245 or the two dsrCABL clusters (CT0851-CT0854, CT2247-2250) abolished sulfur globule oxidation and prevented formation of sulfate from sulfide, whereas deletion of dsr......:quinone oxidoreductases (sqrB/CT0117 and sqrD/CT1087) were deleted, exhibited a decreased sulfide oxidation rate (~50% of wild type), yet formation and consumption of sulfur globules were not affected. The observation that mutants lacking the DSR system maintain efficient growth, suggests that the DSR system is...

  19. CoFe2O4 nanoparticles as oxidase mimic-mediated chemiluminescence of aqueous luminol for sulfite in white wines.

    Zhang, Xiaodan; He, Shaohui; Chen, Zhaohui; Huang, Yuming

    2013-01-30

    Recently, the intrinsic enzyme-like activity of nanoparticles (NPs) has become a growing area of interest. However, the analytical applications of the NP-based enzyme mimetic are mainly concentrated on their peroxidase-like activity; no attempts have been made to investigate the analytical applications based on the oxidase mimic activities of NPs. For the first time, we report that CoFe(2)O(4) NPs were found to possess intrinsic oxidase-like activity and could catalyze luminol oxidation by dissolved oxygen to produce intensified chemiluminescence (CL). The effect of sulfite on CoFe(2)O(4) NP oxidase mimic-mediated CL of aqueous luminol was investigated. It is very interesting that when adding sulfite to the luminol-CoFe(2)O(4) system, the role of sulfite in the luminol-CoFe(2)O(4) NP-sulfite system depends on its concentration. At a relatively low concentration level, sulfite presents an inhibition effect on the luminol-CoFe(2)O(4) NP system. However, it does have an enhancement effect at a higher concentration level. Investigations on the effect of the solution pH and luminol and CoFe(2)O(4) NP concentrations on the kinetic characteristics of the studied CL system in the presence of trace sulfite suggested that the enhancement and inhibition of the luminol-CoFe(2)O(4) NP-sulfite CL system also depended on the solution pH. It seems that the concentrations of luminol and CoFe(2)O(4) NPs did not influence the CL pathway. The possible mechanism of the luminol-CoFe(2)O(4) NP-sulfite CL system was also discussed. On this basis, a flow injection chemiluminescence method was established for the determination of trace sulfite in this study. Under the optimal conditions, the proposed system could respond down to 2.0 × 10(-8) M sulfite. The method has been applied to the determination of trace sulfite in white wine samples with satisfactory results. The results given by the proposed method are in good agreement with those given by the standard titration method. PMID

  20. Sinorhizobium meliloti sigma factors RpoE1 and RpoE4 are activated in stationary phase in response to sulfite.

    Bénédicte Bastiat

    Full Text Available Rhizobia are soil bacteria able to establish a nitrogen-fixing symbiosis with legume plants. Both in soil and in planta, rhizobia spend non-growing periods resembling the stationary phase of in vitro-cultured bacteria. The primary objective of this work was to better characterize gene regulation in this biologically relevant growth stage in Sinorhizobium meliloti. By a tap-tag/mass spectrometry approach, we identified five sigma factors co-purifying with the RNA polymerase in stationary phase: the general stress response regulator RpoE2, the heat shock sigma factor RpoH2, and three extra-cytoplasmic function sigma factors (RpoE1, RpoE3 and RpoE4 belonging to the poorly characterized ECF26 subgroup. We then showed that RpoE1 and RpoE4 i are activated upon metabolism of sulfite-generating compounds (thiosulfate and taurine, ii display overlapping regulatory activities, iii govern a dedicated sulfite response by controlling expression of the sulfite dehydrogenase SorT, iv are activated in stationary phase, likely as a result of endogenous sulfite generation during bacterial growth. We showed that SorT is required for optimal growth of S. meliloti in the presence of sulfite, suggesting that the response governed by RpoE1 and RpoE4 may be advantageous for bacteria in stationary phase either by providing a sulfite detoxification function or by contributing to energy production through sulfite respiration. This paper therefore reports the first characterization of ECF26 sigma factors, the first description of sigma factors involved in control of sulphur metabolism, and the first indication that endogenous sulfite may act as a signal for regulation of gene expression upon entry of bacteria in stationary phase.

  1. Antioxidative Mechanisms of Sulfite and Protein-Derived Thiols during Early Stages of Metal Induced Oxidative Reactions in Beer.

    Lund, Marianne N; Krämer, Anna C; Andersen, Mogens L

    2015-09-23

    The radical-mediated reactions occurring during the early stages of beer storage were studied by following the rate of oxygen consumption, radical formation as detected by electron spin resonance spectroscopy, and concentrations of the antioxidant compounds sulfite and thiols. Addition of either Fe(III) or Fe(II) had similar effects, indicating that a fast redox equilibrium is obtained between the two species in beer. Addition of iron in combination with hydrogen peroxide gave the most pronounced levels of oxidation due to a direct initiation of ethanol oxidation through generation of hydroxyl radicals by the Fenton reaction. The concentration of sulfite decreased more than the thiol concentration, suggesting that thiols play a secondary role as antioxidants by mainly quenching 1-hydroxyethyl radicals that are intermediates in the oxidation of ethanol. Increasing the temperature had a minor effect on the rate of oxygen consumption. PMID:26325117

  2. Structures and reaction pathways of the molybdenum centres of sulfite-oxidizing enzymes by pulsed EPR spectroscopy

    Enemark, John H.; Astashkin, Andrei V.; Raitsimring, Arnold M.

    2008-01-01

    SOEs (sulfite-oxidizing enzymes) are physiologically vital and occur in all forms of life. During the catalytic cycle, the five-co-ordinate square pyramidal oxo-molybdenum active site passes through the Mo(V) state, and intimate details of the structure can be obtained from variable frequency pulsed EPR spectroscopy through the hyperfine and nuclear quadrupole interactions of nearby magnetic nuclei. By employing variable spectrometer operational frequencies, it is possible to optimize the mea...

  3. Effect of Addition of Sodium Dodecyl Sulfite on Physical Properties of Wheat Gluten Films

    ZENG Yuwei; ZHAO Mouming; WANG Jinshui

    2005-01-01

    Films were made from the wheat glutens treated with 5%,10%,15%,20%,25% and 30%(wt% of gluten) of sodium dodecyl sulfite (SDS) in order to improve the properties of the films. Glycerol was used as a plasticizer.An addition of SDS in wheat glutens prior to forming films significantly increased the elongation at break(E) (P<0.05) and reduced notably the water vapor permeability(WVP) (P<0.05). In contrast,a decrease in the tensile strength(TS) of the films from gluten containing-SDS was found.Moreover,a significant decrease in PO2 and PCO2 of films from gluten treated with SDS was noticed. Although SDS-treated gluten film was slightly more yellow and darker than control one, it was not visually detrimental. It is indicated that the treatment with SDS prior to forming films greatly enhances the mechanical properties of wheat gluten films.The obivous improvement in water vapor permeability and extensibility of gluten films means that the use of SDS is a potential choice for improving properties of gluten films. The edible film was used to preserve tomatoes. The experimental results show that the shelf life of tomatoes coated with the edible film is extended, and the nutritional quality is kept well.

  4. Structural insights into dissimilatory sulfite reductases: Structure of desulforubidin from Desulfomicrobium norvegicum

    MargaridaArcher

    2011-04-01

    Full Text Available Dissimilatory sulfite reductases (dSiRs are crucial enzymes in bacterial sulfur-based energy metabolism, which is likely to have been present in some of the earliest life forms on Earth. Several classes of dSiRs have been proposed on the basis of different biochemical and spectroscopic properties. Here, we describe the first structure of a dSiR from the desulforubidin (Drub class isolated from Desulfomicrobium (Dm. norvegicum. The desulforubidin structure is assembled as a2b2c2, in which two DsrC proteins are bound to the core [DsrA]2[DsrB]2 unit, as reported for the desulfoviridin (Dvir structure from Desulfovibrio (D. vulgaris. Unlike desulfoviridin, four sirohemes and eight [4Fe-4S] clusters are present in desulforubidin, but only two of the coupled siroheme-[4Fe-4S] cofactors are likely to be catalytically active. Mass spectrometry studies of purified desulforubidin and desulfoviridin show that both proteins may present different oligomeric complex forms that bind two, one or no DsrC proteins, providing an explanation for conflicting spectroscopic and biochemical results in the literature.

  5. Pattern formation in the iodate-sulfite-thiosulfate reaction-diffusion system.

    Liu, Haimiao; Pojman, John A; Zhao, Yuemin; Pan, Changwei; Zheng, Juhua; Yuan, Ling; Horváth, Attila K; Gao, Qingyu

    2012-01-01

    Sodium polyacrylate-induced pH pattern formation and starch-induced iodine pattern formation were investigated in the iodate-sulfite-thiosulfate (IST) reaction in a one-side fed disc gel reactor (OSFR). As binding agents of the autocatalyst of hydrogen ions or iodide ions, different content of sodium polyacrylate or starch has induced various types of pattern formation. We observed pH pulses, striped patterns, mixed spots and stripes, and hexagonal spots upon increasing the content of sodium polyacrylate and observed iodine pulses, branched patterns, and labyrinthine patterns upon increasing the starch content in the system. Coexistence of a pH front and an iodine front was also studied in a batch IST reaction-diffusion system. Both pH and iodine front instabilities were observed in the presence of sodium polyacrylate, i.e., cellular fronts and transient Turing structures resulting from the decrease in diffusion coefficients of activators. The mechanism of multiple feedback may explain the different patterns in the IST reaction-diffusion system. PMID:22068976

  6. Reaction of hydrogen sulfide with oxygen in the presence of sulfite

    Weres, O.; Tsao, L.

    1983-01-14

    Commonly, abatement of hydrogen sulfide emission from a geothermal powerplant requires that hydrogen sulfide dissolved in the cooling water be eliminated by chemical reaction. Oxidation by atmospheric oxygen is the preferred reaction, but requires a suitable catalyst. Nickel is the most potent and thereby cheapest catalyst for this purpose. One mg/L nickel in the cooling water would allow 99% removal of hydrogen sulfide to be attained. A major drawback of catalytic air oxidation is that colloidal sulfur is a major reaction product; this causes rapid sludge accumulation and deposition of sulfur scale. We studied the kinetics and product distribution of the reaction of hydrogen sulfide with oxygen, catalyzed by nickel. Adding sodium sulfite to the solution completely suppresses formation of colloidal sulfur by converting it to thiosulfate. The oxidation reaction is an autocatalytic, free radical chain reaction. A rate expression for this reaction and a detailed reaction mechanism were developed. Nickel catalyzes the chain initiation step, and polysulfidoradical ions propagate the chains. Several complexes of iron and cobalt were also studied. Iron citrate and iron N-hydroxyEDTA are the most effective iron based catalysts. Uncomplexed cobalt is as effective as nickel, but forms a precipitate of cobalt oxysulfide and is too expensive for practical use. 33 figures, 9 tables.

  7. Reaction of Hydrogen Sulfide with Oxygen in the Presence ofSulfite

    Weres, Oleh; Tsao, Leon

    1983-01-01

    Commonly, abatement of hydrogen sulfide emissions from a geothermal powerplant requires that hydrogen sulfide dissolved in the cooling water be eliminated by chemical reaction. Oxidation by atmospheric oxygen is the preferred reaction, but requires a suitable catalyst. Nickel is the most potent and thereby cheapest catalyst for this purpose. One Mg/L nickel in the cooling water would allow 99% removal of hydrogen sulfide to be attained. A major drawback of catalytic air oxidation is that colloidal sulfur is a major reaction product; this causes rapid sludge accumulation and deposition of sulfur scale. The authors studied the kinetics and product distribution of the reaction of hydrogen sulfide with oxygen, catalyzed by nickel. Adding sodium sulfite to the solution completely suppresses formation of colloidal sulfur by converting it to thiosulfate. The oxidation reaction is an autocatalytic, free radical chain reaction. A rate expression for this reaction and a detailed reaction mechanism were developed. Nickel catalyzes the chain initiation step, and polysulfidoradical ions propagate the chains. Several complexes of iron and cobalt were also studied. Iron citrate and iron N-hydroxyEDT are the most effective iron based catalysts. Uncomplexed cobalt is as effective as nickel, but forms a precipitate of cobalt oxysulfide and is too expensive for practical use.

  8. Ozonolysis mechanism of lignin model compounds and microbial treatment of organic acids produced.

    Nakamura, Y; Daidai, M; Kobayashi, F

    2004-01-01

    Treatment methods comprising ozonolysis and microbial treatment of lignin discharged from the pulp manufacture industries were investigated by using a sulfite pulp wastewater and a lignin model compound, i.e. sodium lignosulfonate. Dynamic behaviors for the formations of intermediate derivatives such as muconic acid, maleic acid, and oxalic acid produced from the ozonolysis of sulfite pulp wastewater were observed from data of UV absorption at 280 nm by a spectrophotometer and at 210 nm by high performance liquid chromatography. The microorganisms that were isolated by the enrichment culture method were used to degrade the organic acids such as oxalic acid and acetic acid. Time courses of biological degradation of these organic acids indicated diauxic growth, which was found in a culture with mixed substrates. In the treatment of sodium lignosulfonate, the ozonolysis and microbial treatment using activated sludge converted sodium lignosulfonate into carbon dioxide and water almost completely. PMID:15461411

  9. Ethanol production from non-detoxified whole slurry of sulfite-pretreated empty fruit bunches at a low cellulase loading.

    Cheng, Jinlan; Leu, Shao-Yuan; Zhu, J Y; Jeffries, Thomas W

    2014-07-01

    Sulfite pretreatment to overcome the recalcitrance of lignocelluloses (SPORL) was applied to an empty fruit bunches (EFB) for ethanol production. SPORL facilitated delignification through lignin sulfonation and dissolution of xylan to result in a highly digestible substrate. The pretreated whole slurry was enzymatically saccharified at a solids loading of 18% using a relatively low cellulase loading of 15 FPU/g glucan and simultaneously fermented without detoxification using Saccharomyces cerevisiae of YRH400. An ethanol yield of 217 L/tonne EFB was achieved at titer of 32 g/L. Compared with literature studies, SPORL produced high ethanol yield and titer with much lower cellulase loading without detoxification. PMID:24874873

  10. C-Terminal Region of Sulfite Reductase Is Important to Localize to Chloroplast Nucleoids in Land Plants

    KOBAYASHI, YUSUKE; Otani, Takuto; Ishibashi, Kota; Shikanai, Toshiharu; Nishimura, Yoshiki

    2016-01-01

    Chloroplast (cp) DNA is compacted into cpDNA-protein complexes, called cp nucleoids. An abundant and extensively studied component of cp nucleoids is the bifunctional protein sulfite reductase (SiR). The preconceived role of SiR as the core cp nucleoid protein, however, is becoming less likely because of the recent findings that SiRs do not associate with cp nucleoids in some plant species, such as Zea mays and Arabidopsis thaliana. To address this discrepancy, we have performed a detailed ph...

  11. 无催化剂条件下亚硫酸盐氧化反应速率%REACTION RATE OF SULFITE OXIDATION WITHOUT CATALYST

    李彦; 金刚善; 张龙; 史建; 陈昌和

    2004-01-01

    @@ INTRODUCTION The control of sulfur dioxide emissions from combustion of coal is very important in environment protection.Wet limestone scrubbing is the most common flue gas desulfurization (FGD) process for controling sulfur dioxide emissions from combustion of coal.This process requires a holding tank where CaSO3 and CaSO4 are crystallized and the make-up CaSO3 is dissolved.Forced oxidation of the sulfite in the holding tank solves the main problem of the disposal of the solid by-product, which is a sludge composed of calcium sulfite and sulfate.

  12. QTL dissection of Lag phase in wine fermentation reveals a new translocation responsible for Saccharomyces cerevisiae adaptation to sulfite.

    Adrien Zimmer

    Full Text Available Quantitative genetics and QTL mapping are efficient strategies for deciphering the genetic polymorphisms that explain the phenotypic differences of individuals within the same species. Since a decade, this approach has been applied to eukaryotic microbes such as Saccharomyces cerevisiae in order to find natural genetic variations conferring adaptation of individuals to their environment. In this work, a QTL responsible for lag phase duration in the alcoholic fermentation of grape juice was dissected by reciprocal hemizygosity analysis. After invalidating the effect of some candidate genes, a chromosomal translocation affecting the lag phase was brought to light using de novo assembly of parental genomes. This newly described translocation (XV-t-XVI involves the promoter region of ADH1 and the gene SSU1 and confers an increased expression of the sulfite pump during the first hours of alcoholic fermentation. This translocation constitutes another adaptation route of wine yeast to sulfites in addition to the translocation VIII-t-XVI previously described. A population survey of both translocation forms in a panel of domesticated yeast strains suggests that the translocation XV-t-XVI has been empirically selected by human activity.

  13. Cloning and characterization of sulfite dehydrogenase, two c-type cytochromes, and a flavoprotein of Paracoccus denitrificans GB17: essential role of sulfite dehydrogenase in lithotrophic sulfur oxidation.

    Wodara, C; Bardischewsky, F; Friedrich, C G

    1997-01-01

    A 13-kb genomic region of Paracoccus dentrificans GB17 is involved in lithotrophic thiosulfate oxidation. Adjacent to the previously reported soxB gene (C. Wodara, S. Kostka, M. Egert, D. P. Kelly, and C. G. Friedrich, J. Bacteriol. 176:6188-6191, 1994), 3.7 kb were sequenced. Sequence analysis revealed four additional open reading frames, soxCDEF. soxC coded for a 430-amino-acid polypeptide with an Mr of 47,339 that included a putative signal peptide of 40 amino acids (Mr of 3,599) with a RR...

  14. 40 CFR Appendix A to Subpart Hhhh... - Method for Determining Free-Formaldehyde in Urea-Formaldehyde Resins by Sodium Sulfite (Iced...

    2010-07-01

    ...-Formaldehyde in Urea-Formaldehyde Resins by Sodium Sulfite (Iced & Cooled) A Appendix A to Subpart HHHH of Part... Appendix A to Subpart HHHH of Part 63—Method for Determining Free-Formaldehyde in Urea-Formaldehyde Resins... Development method of determining free-formaldehyde in urea-formaldehyde resins. This method applies...

  15. 双氧水对亚硫酸铵的氧化特性%Oxidation characteristics of ammonium sulfite using hydrogen peroxide

    王梦秋; 龚惠娟; 樊杨梅; 余珉; 陈泽智; 刘静; 潘敏

    2014-01-01

    在实验中,采用鼓泡氧化反应器分别研究了在空气氧化和臭氧氧化条件下,投加双氧水后亚硫酸铵的氧化率随时间变化情况。结果表明:无论是空气氧化还是臭氧氧化,双氧水的加入均能快速提高亚硫酸铵的氧化率。其中,在空气氧化条件下,对于初始浓度为0.1 mol/L的亚硫酸铵溶液,使氧化率达到60%时的反应时间缩短50 min;在臭氧氧化条件下,对于初始浓度为0.5 mol/L的亚硫酸铵溶液,使氧化率达到60%时的反应时间缩短30 min。但是双氧水也在短时间内消耗殆尽,其后亚硫酸铵的氧化率呈现出与单纯空气氧化或臭氧氧化相同的规律。此外,在双氧水氧化亚硫酸铵过程中,只有部分双氧水参与了氧化反应,而在臭氧氧化条件下双氧水的利用率得到提高,例如对于0.5 mol/L的亚硫酸铵溶液,臭氧气氛下参与反应的双氧水质量分数比空气气氛下高15%,因此臭氧与双氧水可能存在一定的协同作用。%Methods to enhance the oxidation of ammonium sulfite are introduced in this paper. Hydrogen peroxide as an efficient and environment friendly oxidant was used to promote ammonium sulfite oxidation. In the experiment,the bubbling oxidation reactor was used to oxidize ammonium sulfite solution through air aeration or ozone aeration,and the oxidation rate of ammonium sulfite was measured with time. Compared with oxidation through air or ozone aeration,feeding hydrogen peroxide could remarkably increase ammonium sulfite oxidation rate,for example,through air aeration,when oxidation efficiency of 0.1mol/L ammonium sulfite solution reached 60%,reaction time was reduced by 50min and for 0.5mol/L ammonium sulfite solution under the condition of ozone aeration,reaction time was reduced by 30min. However the consumption of hydrogen peroxide was also quite high,resulting in rapid depletion of hydrogen peroxide. In addition,during the ammonium

  16. Protective performances of two anti-graffiti treatments towards sulfite and sulfate formation in SO2 polluted model environment

    Specific strategies for protection are being developed to counter both the staining and corrosive effects of polluted air in cities, as well as to allow for efficient removal of unwanted graffiti paintings. These protection strategies employ molecules with tailored functionalities, e.g. being hydrophobic, while maintaining porosity for molecular water vapour permeation. The present study employs SO2 and water to probe the behaviors of two anti-graffiti treatments, a water-base fluoroalkylsiloxane ('Protectosil Antigraffiti' marketed by Degussa) and an organically modified silicate (Ormosil) synthesized from a polymer chain (polydimethyl siloxane, PDMS) and two network forming alkoxides (Zr propoxide and methyl triethoxy silane, MTES) dissolved in n-propanol, on five building materials, comprising limestone, aged lime mortar, hydrated cement mortar, granite, and brick material. The materials were exposed to a synthetic atmosphere for 20 h in a climate chamber, 0.78 ± 0.03 ppm of SO2 and 95% RH. Diffuse reflectance Fourier transform infrared (DR-FTIR) spectra were registered before and after exposure in the climate chamber in the cases of both treated and untreated samples. DR-FTIR, scanning electron microscope (SEM) images and energy dispersive X-ray (EDX) analyses, suggest the anti-graffiti Ormosil to suppress formation of calcium sulfite hemihydrate (the primary initial product of the reaction of calcium compounds with SO2 and water) on carbonate materials (limestone and lime mortar). In case of the granite, brick and cement mortar, Ormosil has a negligible influence on the SO2 capture. While no sulfite formation was detected by DR-FTIR, gypsum is inferred to form due to metal oxides and minority compounds catalysed oxidation of sulfite to sulfate. In case of brick, this understanding finds support from SEM images as well as EDX. A priori presence of gypsum in hydrated cement mortars prevents positive identification by SEM. However, support for sulfur

  17. Protective performances of two anti-graffiti treatments towards sulfite and sulfate formation in SO 2 polluted model environment

    Carmona-Quiroga, Paula María; Panas, Itai; Svensson, Jan-Erik; Johansson, Lars-Gunnar; Blanco-Varela, María Teresa; Martínez-Ramírez, Sagrario

    2010-11-01

    Specific strategies for protection are being developed to counter both the staining and corrosive effects of polluted air in cities, as well as to allow for efficient removal of unwanted graffiti paintings. These protection strategies employ molecules with tailored functionalities, e.g. being hydrophobic, while maintaining porosity for molecular water vapour permeation. The present study employs SO 2 and water to probe the behaviors of two anti-graffiti treatments, a water-base fluoroalkylsiloxane ("Protectosil Antigraffiti" marketed by Degussa) and an organically modified silicate (Ormosil) synthesized from a polymer chain (polydimethyl siloxane, PDMS) and two network forming alkoxides (Zr propoxide and methyl triethoxy silane, MTES) dissolved in n-propanol, on five building materials, comprising limestone, aged lime mortar, hydrated cement mortar, granite, and brick material. The materials were exposed to a synthetic atmosphere for 20 h in a climate chamber, 0.78 ± 0.03 ppm of SO 2 and 95% RH. Diffuse reflectance Fourier transform infrared (DR-FTIR) spectra were registered before and after exposure in the climate chamber in the cases of both treated and untreated samples. DR-FTIR, scanning electron microscope (SEM) images and energy dispersive X-ray (EDX) analyses, suggest the anti-graffiti Ormosil to suppress formation of calcium sulfite hemihydrate (the primary initial product of the reaction of calcium compounds with SO 2 and water) on carbonate materials (limestone and lime mortar). In case of the granite, brick and cement mortar, Ormosil has a negligible influence on the SO 2 capture. While no sulfite formation was detected by DR-FTIR, gypsum is inferred to form due to metal oxides and minority compounds catalysed oxidation of sulfite to sulfate. In case of brick, this understanding finds support from SEM images as well as EDX. A priori presence of gypsum in hydrated cement mortars prevents positive identification by SEM. However, support for sulfur

  18. Selection and validation of reference genes for quantitative real-time PCR studies during Saccharomyces cerevisiae alcoholic fermentation in the presence of sulfite.

    Nadai, Chiara; Campanaro, Stefano; Giacomini, Alessio; Corich, Viviana

    2015-12-23

    Sulfur dioxide is extensively used during industrial fermentations and contributes to determine the harsh conditions of winemaking together with low pH, high sugar content and increasing ethanol concentration. Therefore the presence of sulfite has to be considered in yeast gene expression studies to properly understand yeast behavior in technological environments such as winemaking. A reliable expression pattern can be obtained only using an appropriate reference gene set that is constitutively expressed regardless of perturbations linked to the experimental conditions. In this work we tested 15 candidate reference genes suitable for analysis of gene expression during must fermentation in the presence of sulfite. New reference genes were selected from a genome-wide expression experiment, obtained by RNA sequencing of four Saccharomyces cerevisiae wine strains grown in enological conditions. Their performance was compared to that of the most common genes used in previous studies. The most popular software based on different statistical approaches (geNorm, NormFinder and BestKeeper) were chosen to evaluate expression stability of the candidate reference genes. Validation was obtained using other wine strains by comparing normalized gene expression data with transcriptome quantification both in the presence and absence of sulfite. Among 15 reference genes tested ALG9, FBA1, UBC6 and PFK1 appeared to be the most reliable while ENO1, PMA1, DED1 and FAS2 were the worst. The most popular reference gene ACT1, widely used for S. cerevisiae gene expression studies, showed a stability level markedly lower than those of our selected reference genes. Finally, as the expression of the new reference gene set remained constant over the entire fermentation process, irrespective of the perturbation due to sulfite addition, our results can be considered also when no sulfite is added to the must. PMID:26325600

  19. Hyphenation of gas-diffusion separation and ion chromatography. Part 1: determination of free sulfite in wines.

    Fäldt, S; Karlberg, B; Frenzel, W

    2001-10-01

    The hyphenation of gas-diffusion separation and ion chromatography (IC) is described as a convenient, reliable, robust, and economic method for in-line sample pre-treatment. The high selectivity associated with this method permits direct analysis of samples containing microparticulates, colloidal matter, and/or high molecular weight compounds. The determination of sulfite serves as a first example of its application. The method is based on the diffusional separation of SO2 following in-line oxidation with hydrogen peroxide to sulfate and final determination of the sulfate formed using IC. The influence of operational parameters has been thoroughly investigated and gas-diffusion cells of different geometries compared with respect to the gas-transfer rates obtained. Application to the analysis of wines demonstrates the utility of the method. PMID:11760049

  20. Determination of free (pH 2.2) sulfite in wines by flow injection analysis: collaborative study.

    Sullivan, J J; Hollingworth, T A; Wekell, M M; Meo, V A; Etemad-Moghadam, A; Phillips, J G; Gump, B H

    1990-01-01

    A method for the determination of free sulfite in wine by flow injection analysis (FIA) is described. The method involves liberation of sulfur dioxide from the wine at pH 2.2, with detection by decolorization of a malachite green solution. The method was collaboratively studied, and the results indicated an average reproducibility of 12% for white wine samples (average level 12.1 ppm SO2) and 26% for red wine samples (average level 3.1 ppm). When the FIA method was compared to an aeration/oxidation method, the results indicated a high degree of correlation between the 2 methods. The FIA method has been adopted by AOAC official first action. PMID:2324033

  1. Alkaline-sulfite pretreatment and use of surfactants during enzymatic hydrolysis to enhance ethanol production from sugarcane bagasse.

    Mesquita, Jéssica Faria; Ferraz, André; Aguiar, André

    2016-03-01

    Sugarcane bagasse is a by-product from the sugar and ethanol industry which contains approximately 70 % of its dry mass composed by polysaccharides. To convert these polysaccharides into fuel ethanol it is necessary a pretreatment step to increase the enzymatic digestibility of the recalcitrant raw material. In this work, sugarcane bagasse was pretreated by an alkaline-sulfite chemithermomechanical process for increasing its enzymatic digestibility. Na2SO3 and NaOH ratios were fixed at 2:1, and three increasing chemical loads, varying from 4 to 8 % m/m Na2SO3, were used to prepare the pretreated materials. The increase in the alkaline-sulfite load decreased the lignin content in the pretreated material up to 35.5 % at the highest chemical load. The pretreated samples presented enhanced glucose yields during enzymatic hydrolysis as a function of the pretreatment severity. The maximum glucose yield (64 %) was observed for the samples pretreated with the highest chemical load. The use of 2.5 g l(-1) Tween 20 in the hydrolysis step further increased the glucose yield to 75 %. Semi-simultaneous hydrolysis and fermentation of the pretreated materials indicated that the ethanol yield was also enhanced as a function of the pretreatment severity. The maximum ethanol yield was 56 ± 2 % for the sample pretreated with the highest chemical load. For the sample pretreated with the lowest chemical load (2 % m/m NaOH and 4 % m/m Na2SO3), adding Tween 20 during the hydrolysis process increased the ethanol yield from 25 ± 3 to 39.5 ± 1 %. PMID:26718203

  2. Congruent Phylogenies of Most Common Small-Subunit rRNA and Dissimilatory Sulfite Reductase Gene Sequences Retrieved from Estuarine Sediments

    Joulian, Catherine; Ramsing, Niels B.; Ingvorsen, Kjeld

    2001-01-01

    The diversity of sulfate-reducing bacteria (SRB) in brackish sediment was investigated using small-subunit rRNA and dissimilatory sulfite reductase (DSR) gene clone libraries and cultivation. The phylogenetic affiliation of the most commonly retrieved clones for both genes was strikingly similar and produced Desulfosarcina variabilis-like sequences from the inoculum but Desulfomicrobium baculatum-like sequences from a high dilution in natural media. Related organisms were subsequently cultiva...

  3. Advances in the use of acidic potassium permanganate as a chemiluminescence reagent: A review

    Adcock, Jacqui L.; Barnett, Neil W.; Barrow, Colin J.; Francis, Paul S., E-mail: psf@deakin.edu.au

    2014-01-07

    Graphical abstract: -- Highlights: •Analytical applications of acidic potassium permanganate chemiluminescence. •Discussion of emitting species and light-producing reaction pathways. •Influence of enhancers such as polyphosphates, formaldehyde and sulfite. •Clinical, forensic, food science, agricultural and environmental applications. -- Abstract: We review the analytical applications of acidic potassium permanganate chemiluminescence published since our previous comprehensive review in mid-2007 to early 2013. This includes a critical evaluation of evidence for the emitting species, the influence of additives such as polyphosphates, formaldehyde, sulfite, thiosulfate, lanthanide complexes and nanoparticles, the development of a generalized reaction mechanism, and the use of this chemistry in pharmaceutical, clinical, forensic, food science, agricultural and environmental applications.

  4. Existence of aa3-type ubiquinol oxidase as a terminal oxidase in sulfite oxidation of Acidithiobacillus thiooxidans.

    Sugio, Tsuyoshi; Hisazumi, Tomohiro; Kanao, Tadayoshi; Kamimura, Kazuo; Takeuchi, Fumiaki; Negishi, Atsunori

    2006-07-01

    It was found that Acidithiobacillus thiooxidans has sulfite:ubiquinone oxidoreductase and ubiquinol oxidase activities in the cells. Ubiquinol oxidase was purified from plasma membranes of strain NB1-3 in a nearly homogeneous state. A purified enzyme showed absorption peaks at 419 and 595 nm in the oxidized form and at 442 and 605 nm in the reduced form. Pyridine ferrohaemochrome prepared from the enzyme showed an alpha-peak characteristic of haem a at 587 nm, indicating that the enzyme contains haem a as a component. The CO difference spectrum of ubiquinol oxidase showed two peaks at 428 nm and 595 nm, and a trough at 446 nm, suggesting the existence of an aa(3)-type cytochrome in the enzyme. Ubiquinol oxidase was composed of three subunits with apparent molecular masses of 57 kDa, 34 kDa, and 23 kDa. The optimum pH and temperature for ubiquinol oxidation were pH 6.0 and 30 degrees C. The activity was completely inhibited by sodium cyanide at 1.0 mM. In contrast, the activity was inhibited weakly by antimycin A(1) and myxothiazol, which are inhibitors of mitochondrial bc(1) complex. Quinone analog 2-heptyl-4-hydoroxyquinoline N-oxide (HOQNO) strongly inhibited ubiquinol oxidase activity. Nickel and tungstate (0.1 mM), which are used as a bacteriostatic agent for A. thiooxidans-dependent concrete corrosion, inhibited ubiquinol oxidase activity 100 and 70% respectively. PMID:16861791

  5. Evolution of Lignocellulosic Macrocomponents in the Wastewater Streams of a Sulfite Pulp Mill: A Preliminary Biorefining Approach

    Tamara Llano

    2015-01-01

    Full Text Available The evolution of lignin, five- and six-carbon sugars, and other decomposition products derived from hemicelluloses and cellulose was monitored in a sulfite pulp mill. The wastewater streams were characterized and the mass balances throughout digestion and total chlorine free bleaching stages were determined. Summative analysis in conjunction with pulp parameters highlights some process guidelines and valorization alternatives towards the transformation of the traditional factory into a lignocellulosic biorefinery. The results showed a good separation of cellulose (99.64% during wood digestion, with 87.23% of hemicellulose and 98.47% lignin dissolved into the waste streams. The following steps should be carried out to increase the sugar content into the waste streams: (i optimization of the digestion conditions increasing hemicellulose depolymerization; (ii improvement of the ozonation and peroxide bleaching stages, avoiding deconstruction of the cellulose chains but maintaining impurity removal; (iii fractionation of the waste water streams, separating sugars from the rest of toxic inhibitors for 2nd generation biofuel production. A total of 0.173 L of second-generation ethanol can be obtained in the spent liquor per gram of dry wood. The proposed methodology can be usefully incorporated into other related industrial sectors.

  6. pH-oscillations in the bromate–sulfite reaction in semibatch and in gel-fed batch reactors

    The simplest bromate oxidation based pH-oscillator, the two component BrO3−–SO32– flow system was transformed to operate under semibatch and closed arrangements. The experimental preconditions of the pH-oscillations in semibatch configuration were predicted by model calculations. Using this information as guideline large amplitude (ΔpH∼3), long lasting (11–24 h) pH-oscillations accompanied with only a 20% increase of the volume in the reactor were measured when a mixture of Na2SO3 and H2SO4 was pumped into the solution of BrO3− with a very low rate. Batch-like pH-oscillations, similar in amplitude and period time appeared when the sulfite supply was substituted by its dissolution from a gel layer prepared previously in the reactor in presence of high concentration of Na2SO3. The dissolution vs time curve and the pH-oscillations in the semibatch and closed systems were successfully simulated. Due to the simplicity in composition and in experimental technique, the semibatch and batch-like BrO3−–SO32– pH-oscillators may become superior to their CSTR (continuous flow stirred tank reactor) version in some present and future applications

  7. pH-oscillations in the bromate-sulfite reaction in semibatch and in gel-fed batch reactors

    Poros, Eszter; Kurin-Csörgei, Krisztina; Szalai, István; Rábai, Gyula; Orbán, Miklós

    2015-06-01

    The simplest bromate oxidation based pH-oscillator, the two component BrO3--SO32- flow system was transformed to operate under semibatch and closed arrangements. The experimental preconditions of the pH-oscillations in semibatch configuration were predicted by model calculations. Using this information as guideline large amplitude (ΔpH˜3), long lasting (11-24 h) pH-oscillations accompanied with only a 20% increase of the volume in the reactor were measured when a mixture of Na2SO3 and H2SO4 was pumped into the solution of BrO3- with a very low rate. Batch-like pH-oscillations, similar in amplitude and period time appeared when the sulfite supply was substituted by its dissolution from a gel layer prepared previously in the reactor in presence of high concentration of Na2SO3. The dissolution vs time curve and the pH-oscillations in the semibatch and closed systems were successfully simulated. Due to the simplicity in composition and in experimental technique, the semibatch and batch-like BrO3--SO32- pH-oscillators may become superior to their CSTR (continuous flow stirred tank reactor) version in some present and future applications.

  8. C-Terminal Region of Sulfite Reductase Is Important to Localize to Chloroplast Nucleoids in Land Plants.

    Kobayashi, Yusuke; Otani, Takuto; Ishibashi, Kota; Shikanai, Toshiharu; Nishimura, Yoshiki

    2016-01-01

    Chloroplast (cp) DNA is compacted into cpDNA-protein complexes, called cp nucleoids. An abundant and extensively studied component of cp nucleoids is the bifunctional protein sulfite reductase (SiR). The preconceived role of SiR as the core cp nucleoid protein, however, is becoming less likely because of the recent findings that SiRs do not associate with cp nucleoids in some plant species, such as Zea mays and Arabidopsis thaliana To address this discrepancy, we have performed a detailed phylogenetic analysis of SiRs, which shows that cp nucleoid-type SiRs share conserved C-terminally encoded peptides (CEPs). The CEPs are likely to form a bacterial ribbon-helix-helix DNA-binding motif, implying a potential role in attaching SiRs onto cp nucleoids. A proof-of-concept experiment was conducted by fusing the nonnucleoid-type SiR from A. thaliana (AtSiR) with the CEP from the cp nucleoid-type SiR of Phaseolus vulgaris The addition of the CEP drastically altered the intra-cp localization of AtSiR to cp nucleoids. Our analysis supports the possible functions of CEPs in determining the localization of SiRs to cp nucleoids and illuminates a possible evolutionary scenario for SiR as a cp nucleoid protein. PMID:27189994

  9. Purification, crystallization and preliminary X-ray analysis of the dissimilatory sulfite reductase from Desulfovibrio vulgaris Miyazaki F.

    Ogata, Hideaki; Shomura, Yasuhito; Goenka Agrawal, Aruna; Kaur, Amrit Pal; Gärtner, Wolfgang; Higuchi, Yoshiki; Lubitz, Wolfgang

    2010-11-01

    Dissimilatory sulfite reductase (Dsr) plays an important role in sulfate respiration in many sulfate-reducing bacteria. Dsr from Desulfovibrio vulgaris Miyazaki F has been purified and crystallized at 277 K using the sitting-drop vapour-diffusion method with PEG 3350 and potassium thiocyanate as precipitants. A data set was collected to 3.7 Å resolution from a single crystal at 100 K using synchrotron radiation. The Dsr crystal belonged to space group P4(1)2(1)2, with unit-cell parameters a = b = 163.26, c = 435.32 Å. The crystal structure of Dsr was determined by the molecular-replacement method based on the three-dimensional structure of Dsr from D. vulgaris Hildenborough. The crystal contained three α(2)β(2)γ(2) units per asymmetric unit, with a Matthews coefficient (V(M)) of 2.35 Å(3) Da(-1); the solvent content was estimated to be 47.7%. PMID:21045297

  10. Investigation of a novel ternary electrolyte based on dimethyl sulfite and lithium difluoromono(oxalato)borate for lithium ion batteries

    Chen, Renjie; Zhu, Lu; Wu, Feng; Li, Li; Zhang, Rong; Chen, Shi

    2014-01-01

    Lithium difluoromono(oxalato)borate (LiODFB) has been used as a novel lithium salt for battery in recent studies. In this study, a series of novel electrolytes has been prepared by adding 30 vol% dimethyl sulfite (DMS) or dimethyl carbonate (DMC) as co-solvent into an ethylene carbonate (EC)/ethyl methyl carbonate (EMC) + LiX mixture, in which the LiX could be LiClO4, LiODFB, LiBOB, LiTFSI, or LiCF3SO3. These ternary electrolytes have been investigated for use in lithium ion batteries. FT-IR spectroscopy analysis shows that characteristic functional groups (-CO3, -SO3) undergo red-shift or blue-shift with the addition of different lithium salts. The LiODFB-EC/EMC/DMS electrolyte exhibits high ionic conductivity, which is mainly because of the low melting point of DMS, and LiODFB possessing high solubility. The Li/MCMB cells containing this novel electrolyte exhibit high capacities, good cycling performance, and excellent rate performance. These performances are probably because both LiODFB and DMS can assist in the formation of SEI films by reductive decomposition. Additionally, the discharge capacity of Li/LiCoO2 half cell containing LiODFB-EC/EMC/DMS electrolyte is 130.9 mAh g-1 after 50 cycles, and it is very comparable with the standard-commercial electrolyte. The results show that this study produces a promising electrolyte candidate for lithium ion batteries.

  11. Fermentation Kinetics for Xylitol Production by a Pichia stipitis d-Xylulokinase Mutant Previously Grown in Spent Sulfite Liquor

    Rodrigues, Rita C. L. B.; Lu, Chenfeng; Lin, Bernice; Jeffries, Thomas W.

    Spent sulfite pulping liquor (SSL) contains lignin, which is present as lignosulfonate, and hemicelluloses that are present as hydrolyzed carbohydrates. To reduce the biological oxygen demand of SSL associated with dissolved sugars, we studied the capacity of Pichia stipitis FPL-YS30 (xyl3Δ) to convert these sugars into useful products. FPL-YS30 produces a negligible amount of ethanol while converting xylose into xylitol. This work describes the xylose fermentation kinetics of yeast strain P.stipitis FPL-YS30. Yeast was grown in rich medium supplemented with different carbon sources: glucose, xylose, or ammonia-base SSL. The SSL and glucose-acclimatized cells showed similar maximum specific growth rates (0.146 h-1). The highest xylose consumption at the beginning of the fermentation process occurred using cells precultivated in xylose, which showed relatively high specific activity of glucose-6-phosphate dehydrogenase (EC 1.1.1.49). However, the maximum specific rates of xylose consumption (0.19 gxylose/gcel h) and xylitol production (0.059 gxylitol/gcel h) were obtained with cells acclimatized in glucose, in which the ratio between xylose reductase (EC 1.1.1.21) and xylitol dehydrogenase (EC 1.1.1.9) was kept at higher level (0.82). In this case, xylitol production (31.6 g/l) was 19 and 8% higher than in SSL and xylose-acclimatized cells, respectively. Maximum glycerol (6.26 g/l) and arabitol (0.206 g/l) production were obtained using SSL and xylose-acclimatized cells, respectively. The medium composition used for the yeast precultivation directly reflected their xylose fermentation performance. The SSL could be used as a carbon source for cell production. However, the inoculum condition to obtain a high cell concentration in SSL needs to be optimized.

  12. Community composition and distribution of sulfate- and sulfite-reducing prokaryotes in sediments from the Changjiang estuary and adjacent East China Sea

    He, Hui; Zhen, Yu; Mi, Tiezhu; Xu, Bochao; Wang, Guoshan; Zhang, Yu; Yu, Zhigang

    2015-11-01

    Sulfate- and sulfite-reducing prokaryotes (SSRP) communities play a vital role in both sulfur and carbon cycles. Community composition and abundance of SSRP were investigated using dissimilatory sulfite reductase β subunit (dsrB) gene sequencing in sediments from the Changjiang estuary and its adjacent area in the East China Sea (ECS). Clone libraries were constructed and real-time fluorescence quantitative polymerase chain reaction (qPCR) was applied to understand the community information of SSRP. In addition to sequences affiliated to sulfate-reducing prokaryotes (SRP), those affiliated with sulfite-reducing prokaryotes (SiRP) were also observed. Four phylotypes of SRP in this study showed genetic similarity to Desulfobulbaceae, Syntrophobacteraceae, Desulfobacteraceae and Peptococcaceae, and an unknown group that could not be clearly affiliated with known lineages was found. Salinity, temperature and contents of total organic carbon (TOC) were most closely correlated with the SSRP communities by canonical correspondence analysis (CCA). 210Pb activities demonstrated the sedimentary environment at S33 was more stable than that at S31. Intense resuspension and reconstruction of sediments made the vertical abundance profile of SSRP fluctuate violently. For surface sediments, the dsrB gene copy numbers near the Changjiang estuary were higher than those in the mouth of Hangzhou Bay and the mud deposits along the Zhejiang coast, and contents of TOC were positively related to the copy numbers of dsrB gene. Our data provided valuable information to achieve a better understanding of the potential role of SSRP in sediments from the Changjiang estuary and adjacent East China Sea.

  13. 湿法烟气脱硫环境下亚硫酸钙的非催化氧化%NON-CATALYTIC OXIDATION KINETICS OF CALCIUM SULFITE IN WET LIMESTONE-GYPSUM FGD PROCESS

    杜谦; 吴少华; 朱群益; 秦裕琨

    2003-01-01

    A study on non-catalytic oxidation kinetics of calcium sulfite is presented under typical conditions of wet flue gas desulfurization (FGD)in this paper. A laboratory-scale mechanically stirred tank reactor is used with continuous feed of both gas and liquid phase. The results show that increasing CaSO3 load from a lower value, the reaction rate increases and is limited by solid sulfite dissolution. The oxidation rate limitation is observed at loads exceeding certain concentration. The rate limitation is possibly caused by solid sulfite solubility or oxygen gas-liquid diffusion. The experimental conclusions are useful for design and operation of the holding tank in forced-oxidation wet FGD.

  14. Hybrid sequential injection-flow injection manifold for the spectrophotometric determination of total sulfite in wines using o-phthalaldehyde and gas-diffusion.

    Tzanavaras, Paraskevas D; Thiakouli, Eleni; Themelis, Demetrius G

    2009-03-15

    A new automated spectrophotometric method for the determination of total sulfite in white and red wines is reported. The assay is based on the reaction of o-phthalaldehyde (OPA) and ammonium chloride with the analyte in basic medium under SI conditions. Upon on-line alkalization with NaOH, a blue product is formed having an absorption maximum at 630 nm. The parameters affecting the reaction - temperature, pH, ionic strength, amount concentration and volume of OPA, amount concentration of ammonium chloride, flow rate and reaction coil length - and the gas-diffusion process - sample and HCl volumes, length of mixing coil, donor flow rate - were studied. The proposed method was validated in terms of linearity (1-40 mgL(-1), r=0.9997), limit of detection (c(L)=0.3 mgL(-1)) and quantitation (c(Q)=1.0 mgL(-1)), precision (s(r)=2.2% at 20 mgL(-1) sulfite, n=12) and selectivity. The applicability of the analytical procedure was evaluated by analyzing white and red wine samples, while the accuracy as expressed by recovery experiments ranged between 96% and 106%. PMID:19159773

  15. Indirect determination of sulfite using a polyphenol oxidase biosensor based on a glassy carbon electrode modified with multi-walled carbon nanotubes and gold nanoparticles within a poly(allylamine hydrochloride) film.

    Sartori, Elen Romão; Vicentini, Fernando Campanhã; Fatibello-Filho, Orlando

    2011-12-15

    The modification of a glassy carbon electrode with multi-walled carbon nanotubes and gold nanoparticles within a poly(allylamine hydrochloride) film for the development of a biosensor is proposed. This approach provides an efficient method used to immobilize polyphenol oxidase (PPO) obtained from the crude extract of sweet potato (Ipomoea batatas (L.) Lam.). The principle of the analytical method is based on the inhibitory effect of sulfite on the activity of PPO, in the reduction reaction of o-quinone to catechol and/or the reaction of o-quinone with sulfite. Under the optimum experimental conditions using the differential pulse voltammetry technique, the analytical curve obtained was linear in the concentration of sulfite in the range from 0.5 to 22 μmol L(-1) with a detection limit of 0.4 μmol L(-1). The biosensor was applied for the determination of sulfite in white and red wine samples with results in close agreement with those results obtained using a reference iodometric method (at a 95% confidence level). PMID:22099673

  16. Protective performances of two anti-graffiti treatments towards sulfite and sulfate formation in SO{sub 2} polluted model environment

    Carmona-Quiroga, Paula Maria, E-mail: paulacq@ietcc.csic.es [Eduardo Torroja Institute for Construction Science, Serrano Galvache 4 St, 28033 Madrid (Spain); Panas, Itai; Svensson, Jan-Erik; Johansson, Lars-Gunnar [Department of Chemistry and Biotechnology, Environmental Inorganic Chemistry, Chalmers University of Technology, S-41296 Goethenburg (Sweden); Blanco-Varela, Maria Teresa; Martinez-Ramirez, Sagrario [Eduardo Torroja Institute for Construction Science, Serrano Galvache 4 St, 28033 Madrid (Spain)

    2010-11-15

    Specific strategies for protection are being developed to counter both the staining and corrosive effects of polluted air in cities, as well as to allow for efficient removal of unwanted graffiti paintings. These protection strategies employ molecules with tailored functionalities, e.g. being hydrophobic, while maintaining porosity for molecular water vapour permeation. The present study employs SO{sub 2} and water to probe the behaviors of two anti-graffiti treatments, a water-base fluoroalkylsiloxane ('Protectosil Antigraffiti' marketed by Degussa) and an organically modified silicate (Ormosil) synthesized from a polymer chain (polydimethyl siloxane, PDMS) and two network forming alkoxides (Zr propoxide and methyl triethoxy silane, MTES) dissolved in n-propanol, on five building materials, comprising limestone, aged lime mortar, hydrated cement mortar, granite, and brick material. The materials were exposed to a synthetic atmosphere for 20 h in a climate chamber, 0.78 {+-} 0.03 ppm of SO{sub 2} and 95% RH. Diffuse reflectance Fourier transform infrared (DR-FTIR) spectra were registered before and after exposure in the climate chamber in the cases of both treated and untreated samples. DR-FTIR, scanning electron microscope (SEM) images and energy dispersive X-ray (EDX) analyses, suggest the anti-graffiti Ormosil to suppress formation of calcium sulfite hemihydrate (the primary initial product of the reaction of calcium compounds with SO{sub 2} and water) on carbonate materials (limestone and lime mortar). In case of the granite, brick and cement mortar, Ormosil has a negligible influence on the SO{sub 2} capture. While no sulfite formation was detected by DR-FTIR, gypsum is inferred to form due to metal oxides and minority compounds catalysed oxidation of sulfite to sulfate. In case of brick, this understanding finds support from SEM images as well as EDX. A priori presence of gypsum in hydrated cement mortars prevents positive identification by SEM

  17. A study of electrochemically-induced corrosion of low carbon steel in a medium modelling acid rain

    Complementary electrochemical, spectrophotometric and electron microsopic investigations were made in addition to the conversion electron Moessbauer spectroscopic (CEMS) measurements to learn more about the mechanism of corrosion of low carbon steel samples in aqueous sulfate and sulfite containing sulfate solutions (pH 3.5, 6.5 and 8.5). Passivation of iron in pure sulfate solution was studied in detail in earlier papers. In the present work, we used a solution containing both sulfate and sulfite anions to obtain more information about the effect of acid rain on low carbon steel samples. The compositions and thicknesses of the passive films formed due to the electrochemical treatments were determined from the CEM spectra. γ-FeOOH was found in each case on the surface of the samples; nevertheless, at pH 3.5 the sextet belonging to Fe3C appears in the CEM spectra, and also FeSO4 . H2O was detected in low concentration after the shortest polarization time (90 min). The results of the applied methods proved that the sulfite ions induce pitting corrosion at pH 3.5 and 6.5, while the measurements referred to suppressed pitting at pH 8.5. (orig.)

  18. Photoproduction of glyoxylic acid in model wine: Impact of sulfur dioxide, caffeic acid, pH and temperature.

    Grant-Preece, Paris; Schmidtke, Leigh M; Barril, Celia; Clark, Andrew C

    2017-01-15

    Glyoxylic acid is a tartaric acid degradation product formed in model wine solutions containing iron and its production is greatly increased by exposure to UV-visible light. In this study, the combined effect of sulfur dioxide, caffeic acid, pH and temperature on the light-induced (⩾300nm) production of glyoxylic acid in model wine containing tartaric acid and iron was investigated using a Box-Behnken experimental design and response surface methodology (RSM). Glyoxylic acid produced in the irradiated model wine was present in free and hydrogen sulfite adduct forms and the measured total, free and percentage free glyoxylic acid values were modeled using RSM. Sulfur dioxide significantly decreased the total amount of glyoxylic acid produced, but could not prevent its production, while caffeic acid showed no significant impact. The interaction between pH and temperature was significant, with low pH values and low temperatures giving rise to higher levels of total glyoxylic acid. PMID:27542478

  19. Lithium Organic Borate Salt and Sulfite Functional Electrolytes%有机硼酸锂盐及亚硫酸酯类功能电解质材料

    陈人杰; 何舟影; 吴锋

    2011-01-01

    随着锂离子电池对高安全性、高容量、高功率等性能的技术需求,新型功能电解质材料的研究开发成为锂离子电池新材料领域研发工作的重点.本文对面向锂离子电池应用的功能电解质材料锂盐和添加剂的最新研究进展作了较为全面的阐述,其中重点介绍了本研究团队近年来在面向改善锂离子电池安全性能、提高其温度适应性、增强电解质与电极材料相容特性等方面研究开发的系列基于双草酸硼酸锂[LiBOB]及二氟草酸硼酸锂[LiODFB]等有机硼酸锂盐和亚硫酸酯类等添加剂的新型功能电解质材料,其表现出高的热稳定性和良好的电化学性能.而且,其中的有机硼酸锂盐和亚硫酸酯还可以作为SEI成膜材料进行应用,其在石墨电极表面可形成稳定的SEI膜,有利于改善电池的循环寿命、自放电、库仑效率和不可逆容量衰减.最后,本文探讨了当前存在的问题及未来的研究方向,并对其应用前景进行了展望.%With the rapid development of lithium ion batteries with higher energy density, higher power density and high security, the research of new functional electrolytes has attracted considerable attention in novel materials field for lithium ion batteries.In this paper, the recent research advances of key technologies on the application of lithium salts and additive functional electrolytes in lithium ion batteries are reviewed, especially on the results of our research team focusing on new functional electrolytes based on lithium organic borate salt, such as lithium bis(oxalato) borate [LiBOB]and lithium oxalyldifluoroborate [LiODFB], and sulfite additives for the purpose of improving security, temperature adaptability and the compatibility between electrolytes and electrodes of lithium ion batteries.These electrolytes exhibit high thermal stability and good electrochemical properties.Moreover, lithium organic borate salt and sulfite have been

  20. 马来酸酐及亚硫酸氢钠改性环氧树脂的研究%MODIFICATION OF EPOXY RESIN WITH MALEIC ANHYDRIDE AND SODIUM HYDROGEN SULFITE

    李鹏; 张雪梅; 程斌; 杨小平; 董玲

    2013-01-01

    Epoxy resin was modified by maleic anhydride, then reacted with sodium hydrogen sulfite to attach sulfonyl group on it. The effects of reaction temperature, catalyst amount, the concentration of raw materials, and the ratio of mixed solvents on the synthesis process were investigated experimentally during the process of epoxy resin modified by maleic anhydride. The side reaction which produces cross-linked molecular will be significantly enhanced with increasing temperature, concentration of catalyst and raw material. When solvent ratio of methylbenzene and acetone is relative low, acid value is hard to monitor and side reaction with cross-lined products is enhanced, which is not conducive to the reaction. In further reaction with sodium hydrogen, structure of product is examined through elemental analysis to monitor, and particle size distribution of the according modified epoxy emulsion is monitored by Size Distribution Modal Analysis. Particle size of self-emulsifier aqueous dispersion system prepared under optimal conditions is about 100nm, which also shows great stability.%本文首先用马来酸酐对环氧树脂进行改性,并进一步与亚硫酸氢钠反应制备带磺酸基团的水性环氧树脂.系统地研究了马来酸酐改性环氧树脂的反应温度、催化剂用量、原料浓度及混合溶剂比例对反应的影响.随着温度的升高,催化剂用量和原料浓度的增加,生成交联网状产物的副反应都会明显增强,体系易凝胶;溶剂甲苯与丙酮的混合比例较低时,反应体系酸值难于准确监测,并且生成交联网状产物的副反应增强不利于反应的顺利进行.在马来酸酐改性环氧树脂进一步与亚硫酸氢钠反应制备具有水分散性的环氧树脂过程中,用元素分析法测定产物结构中的硫元素含量,并分析了乳液的粒径分布,适宜条件下制备的水性环氧树脂分散体系平均粒径为1 10nm,粒径分布窄,具有良好的分散稳定性.

  1. Metal-organic frameworks from zinc sulfite clusters, chains, and sheets: 4-connected, (3,4)-connected 3-D frameworks and 2-D arrays of catenane-like interlocking rings.

    Nguyen, Dan-Tam; Chew, Emily; Zhang, Qichun; Choi, Alice; Bu, Xianhui

    2006-12-25

    Even though open-framework solids have been made in a variety of compositions such as silicates, phosphates, germanates, borates, and phosphites, few are known that are based on trigonal-pyramidal sulfite anions. We report here the first synthetic and structural studies of metal-organic framework materials in the zinc sulfite composition. It is demonstrated here that Zn2+ and SO32- can form various neutral inorganic subunits that can be 0-D clusters, 1-D chains, or 2-D sheets. These inorganic subunits of different dimensionality can subsequently be connected into extended frameworks of higher dimensionality through bifunctional ligands. In (ZnSO3)2en, infinite corrugated ZnSO3 layers are pillared by ethylenediamine (en) molecules into a 3-D network that can be classified as a (3,4)-connected net based on tetrahedral Zn nodes and trigonal-pyramidal S nodes. In (ZnSO3)pip, infinite ZnSO3 chains are cross-linked with piperazine molecules into a 3-D framework that can be classified as 4-connected net based on tetrahedral Zn nodes only. In (ZnSO3)2(TMDPy)2, (ZnSO3)2 dimers are doubly bridged by trimethylenedipyridine molecules into an infinite chain with a string of circles. Each circle along the chain is interlocked with another circle from a chain in the perpendicular direction, creating a 2-D pattern with an infinite-square array of catenane-like units. PMID:17173428

  2. Molecular Modeling of Ammonium, Calcium, Sulfur, and Sodium Lignosulphonates in Acid and Basic Aqueous Environments

    Salazar Valencia, P. J.; Bolívar Marinez, L. E.; Pérez Merchancano, S. T.

    2015-12-01

    Lignosulphonates (LS), also known as lignin sulfonates or sulfite lignin, are lignins in sulfonated forms, obtained from the "sulfite liquors," a residue of the wood pulp extraction process. Their main utility lies in its wide range of properties, they can be used as additives, dispersants, binders, fluxing, binder agents, etc. in fields ranging from food to fertilizer manufacture and even as agents in the preparation of ion exchange membranes. Since they can be manufactured relatively easy and quickly, and that its molecular size can be manipulated to obtain fragments of very low molecular weight, they are used as transport agents in the food industry, cosmetics, pharmaceutical and drug development, and as molecular elements for the treatment of health problems. In this paper, we study the electronic structural and optical characteristics of LS incorporating ammonium, sulfur, calcium, and sodium ions in acidic and basic aqueous media in order to gain a better understanding of their behavior and the very interesting properties exhibit. The studies were performed using the molecular modeling program HyperChem 5 using the semiempirical method PM3 of the NDO Family (neglect of differential overlap), to calculate the structural properties. We calculated the electronic and optical properties using the semiempirical method ZINDO / CI.

  3. 飞机草鞣质的亚硫酸化改性及其鞣性研究%Sulfitation of Eupatorium Odoratum L.Tannin and its Tanning Ability

    车玮; 常杰鲜; 陈继平; 龚英

    2015-01-01

    菊科植物飞机草具有一定的鞣制性能,但仍存在着传统植物鞣剂增厚率太高、颜色深、收缩温度低等缺点。本文期望通过亚硫酸化改性克服上述不足。首先采用正交实验法对飞机草茎和叶提取物进行亚硫酸化改性,接着采用改性物处理酸裸皮,处理后的坯革颜色在浅黄棕到深黄棕范围变化,增厚率低于传统植鞣革,为5.0%~6.7%,收缩温度可提高37益。采用改性物与铝盐结合鞣制,坯革收缩温度可达90益,基本达到无铬鞣革的耐湿热稳定性要求。研究首次获得了飞机草亚硫酸化改性物部分理化性质及其鞣制性能,可为进一步开发这种新植物鞣剂提供一些参考。%The composites Eupatorium odoratum L. was introduced as a kind of tanning agent, however, it was of the typical disadvantages for vegetable tannins, such as over strong thickening, deep color and low shrinkage temperature. These shortages were expected to be avoided by sulfitation in this study. Firstly, the orthogonal experiments were designed to study the sulfitation, and then these products were used to treat pickled pigskins. As proved, the treated pigskins had a light color like yellowish-brown and 5.0%-6.7%thickening rate, which was lower than that of the traditional vegetable leather. More important was that the shrinkage temperature was elevated by 37℃. Subsequently, some modified products were exploited to treat pigskins in the presence of aluminum tanning agent, and the results showed that the shrinkage temperature was elevated up to 90 ℃, which could meet with the requirement of the chrome-free tanned leather. In a word, some physical-chemical properties were obtained for the sulfited products of Eupatorium odoratum L., which would provide some basis for developing the new vegetable tanning agent.

  4. Cysteic acid and taurine synthesis from sulphate in the chick embryo; Synthese de l'acide cysteique et de la taurine a partir du sulfate dans l'oeuf embryonne de poule

    Chapeville, F. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1960-07-01

    The formation of taurine from sulphate was studied in the chick embryo using the radioisotopes of: sulphur, carbon and hydrogen. The following reactions occur: 1) reduction of sulphate to sulphite; 2) fixation of the sulphite on a carbon chain with an amino group, resulting from desulphydration of L-cysteine, which leads to the formation of L-cysteic acid; 3) decarboxylation of L-cysteic acid. Reaction (1) takes place only in the endo-dermal cells of the yolk sac; reaction (2) in these same cells and in the yolk; reaction (3) is general, localized in the yolk sac, in the yolk as well as in the tissues of the embryo itself. The enzyme which catalyses reaction (2) has been purified; the coenzyme is pyridoxal phosphate. The desulphydration of cysteine by this enzyme is a reversible reaction. In non-physiological conditions of concentration and temperature, pyridoxal phosphate catalyses in the presence of metallic ions, the desulphydration of cysteine and the formation of cysteic acid from sulphite. (author) [French] On a montre que la formation de taurine a partir de sulfate dans I'oeuf embryonne de poule, etudiee a l'aide des radioisotopes, du soufre, du carbone et de l'hydrogene, correspond aux reactions suivantes: 1) reduction du sulfate en sulfite; 2) fixation du sulfite sur une chaine tricarbonee et aminee provenant de la desulfhydration de la L-cysteine, fixation conduisant a la formation d'acide L-cysteique; 3) decarboxylation de l'acide L-cysteique. La reaction (1) a lieu uniquement dans les cellules de l'endoderme du sac vitellin; la reaction (2) dans les memes cellules et dans le vitellus; la reaction (3) est plus generale, elle est localisee dans le sac vitellin, dans le vitellus et dans les tissus de l'embryon. L'enzyme qui catalyse la reaction (2) a ete purifie; il possede le phosphate de pyridoxal comme coenzyme. La desulfhydration de la cysteine par cet enzyme est une reaction reversible. Dans les conditions non

  5. Amino acids

    Amino acids are organic compounds that combine to form proteins . Amino acids and proteins are the building blocks of life. When proteins are digested or broken down, amino acids are left. The human body uses amino acids ...

  6. Solubilities of 2-Naphthalenesulfonic Acid Monohydrate and Sodium 2-Naphthalenesulfonate in Sulfuric Acid Solution and Their Application for Preparing Sodium 2-Naphthalenesulfonate

    张凤宝; 景晖; 朱文宇; 张林; 刘博; 张国亮; 夏清

    2016-01-01

    The solubilities of 2-naphthalenesulfonic acid monohydrate and sodium 2-naphthalenesulfonate in sul-furic acid solutions were measured at temperatures ranging from 278.15 to 338.15 K by using a dynamic method. The concentration of sulfuric acid solution ranged from 0 to 80wt%,. The solubilities of 2-naphthalenesulfonic acid monohydrate and sodium 2-naphthalenesulfonate increased with temperature, and both of them were the lowest at 70wt%, of sulfuric acid solution(03w=0.70)while the highest in pure water. The solubility data were correlated by the modified Apelblat equation. Based on the solubility difference between 2-naphthalenesulfonic acid monohy-drate and sodium 2-naphthalenesulfonate, a new technique in which sodium sulfate was used to replace sodium sulfite in the neutralization reaction was developed. The suitable mole ratio of H2O to Na2SO4 in the neutralization reaction was 80∶1, and that of 2-naphthalenesulfonic acid monohydrate to Na2SO4 was 3.2∶1. The material bal-ance under the suitable mole ratios was given and discussed.

  7. Lactic Acid Production from Pretreated Hydrolysates of Corn Stover by a Newly Developed Bacillus coagulans Strain

    Jiang, Ting; Qiao, Hui; Zheng, Zhaojuan; Chu, Qiulu; Li, Xin; Yong, Qiang; Ouyang, Jia

    2016-01-01

    An inhibitor-tolerance strain, Bacillus coagulans GKN316, was developed through atmospheric and room temperature plasma (ARTP) mutation and evolution experiment in condensed dilute-acid hydrolysate (CDH) of corn stover. The fermentabilities of other hydrolysates with B. coagulans GKN316 and the parental strain B. coagulans NL01 were assessed. When using condensed acid-catalyzed steam-exploded hydrolysate (CASEH), condensed acid-catalyzed liquid hot water hydrolysate (CALH) and condensed acid-catalyzed sulfite hydrolysate (CASH) as substrates, the concentration of lactic acid reached 45.39, 16.83, and 18.71 g/L by B. coagulans GKN316, respectively. But for B. coagulans NL01, only CASEH could be directly fermented to produce 15.47 g/L lactic acid. The individual inhibitory effect of furfural, 5-hydroxymethylfurfural (HMF), vanillin, syringaldehyde and p-hydroxybenzaldehyde (pHBal) on xylose utilization by B. coagulans GKN316 was also studied. The strain B. coagulans GKN316 could effectively convert these toxic inhibitors to the less toxic corresponding alcohols in situ. These results suggested that B. coagulans GKN316 was well suited to production of lactic acid from undetoxified lignocellulosic hydrolysates. PMID:26863012

  8. Lactic Acid Production from Pretreated Hydrolysates of Corn Stover by a Newly Developed Bacillus coagulans Strain.

    Ting Jiang

    Full Text Available An inhibitor-tolerance strain, Bacillus coagulans GKN316, was developed through atmospheric and room temperature plasma (ARTP mutation and evolution experiment in condensed dilute-acid hydrolysate (CDH of corn stover. The fermentabilities of other hydrolysates with B. coagulans GKN316 and the parental strain B. coagulans NL01 were assessed. When using condensed acid-catalyzed steam-exploded hydrolysate (CASEH, condensed acid-catalyzed liquid hot water hydrolysate (CALH and condensed acid-catalyzed sulfite hydrolysate (CASH as substrates, the concentration of lactic acid reached 45.39, 16.83, and 18.71 g/L by B. coagulans GKN316, respectively. But for B. coagulans NL01, only CASEH could be directly fermented to produce 15.47 g/L lactic acid. The individual inhibitory effect of furfural, 5-hydroxymethylfurfural (HMF, vanillin, syringaldehyde and p-hydroxybenzaldehyde (pHBal on xylose utilization by B. coagulans GKN316 was also studied. The strain B. coagulans GKN316 could effectively convert these toxic inhibitors to the less toxic corresponding alcohols in situ. These results suggested that B. coagulans GKN316 was well suited to production of lactic acid from undetoxified lignocellulosic hydrolysates.

  9. Lactic Acid Production from Pretreated Hydrolysates of Corn Stover by a Newly Developed Bacillus coagulans Strain.

    Jiang, Ting; Qiao, Hui; Zheng, Zhaojuan; Chu, Qiulu; Li, Xin; Yong, Qiang; Ouyang, Jia

    2016-01-01

    An inhibitor-tolerance strain, Bacillus coagulans GKN316, was developed through atmospheric and room temperature plasma (ARTP) mutation and evolution experiment in condensed dilute-acid hydrolysate (CDH) of corn stover. The fermentabilities of other hydrolysates with B. coagulans GKN316 and the parental strain B. coagulans NL01 were assessed. When using condensed acid-catalyzed steam-exploded hydrolysate (CASEH), condensed acid-catalyzed liquid hot water hydrolysate (CALH) and condensed acid-catalyzed sulfite hydrolysate (CASH) as substrates, the concentration of lactic acid reached 45.39, 16.83, and 18.71 g/L by B. coagulans GKN316, respectively. But for B. coagulans NL01, only CASEH could be directly fermented to produce 15.47 g/L lactic acid. The individual inhibitory effect of furfural, 5-hydroxymethylfurfural (HMF), vanillin, syringaldehyde and p-hydroxybenzaldehyde (pHBal) on xylose utilization by B. coagulans GKN316 was also studied. The strain B. coagulans GKN316 could effectively convert these toxic inhibitors to the less toxic corresponding alcohols in situ. These results suggested that B. coagulans GKN316 was well suited to production of lactic acid from undetoxified lignocellulosic hydrolysates. PMID:26863012

  10. Integration of the Mini-Sulfide Sulfite Anthraquinone (MSS-AQ) Pulping Process and Black Liquor Gasification in a Pulp Mill

    Hasan Jameel, North Carolina State University; Adrianna Kirkman, North Carolina State University; Ravi Chandran,Thermochem Recovery International Brian Turk Research Triangle Institute; Brian Green, Research Triangle Institute

    2010-01-27

    As many of the recovery boilers and other pieces of large capital equipment of U.S. pulp mills are nearing the end of their useful life, the pulp and paper industry will soon need to make long-term investments in new technologies. The ability to install integrated, complete systems that are highly efficient will impact the industry’s energy use for decades to come. Developing a process for these new systems is key to the adoption of state-of-the-art technologies in the Forest Products industry. This project defined an integrated process model that combines mini-sulfide sulfite anthraquinone (MSS-AQ) pulping and black liquor gasification with a proprietary desulfurization process developed by the Research Triangle Institute. Black liquor gasification is an emerging technology that enables the use of MSS-AQ pulping, which results in higher yield, lower bleaching cost, lower sulfur emissions, and the elimination of causticization requirements. The recently developed gas cleanup/absorber technology can clean the product gas to a state suitable for use in a gas turbine and also regenerate the pulping chemicals needed to for the MSS-AQ pulping process. The combination of three advanced technologies into an integrated design will enable the pulping industry to achieve a new level of efficiency, environmental performance, and cost savings. Because the three technologies are complimentary, their adoption as a streamlined package will ensure their ability to deliver maximum energy and cost savings benefits. The process models developed by this project will enable the successful integration of new technologies into the next generation of chemical pulping mills. When compared to the Kraft reference pulp, the MSS-AQ procedures produced pulps with a 10-15 % yield benefit and the ISO brightness was 1.5-2 times greater. The pulp refined little easier and had a slightly lower apparent sheet density (In both the cases). At similar levels of tear index the MSS-AQ pulps also

  11. Acid Rain.

    Openshaw, Peter

    1987-01-01

    Provides some background information on acid deposition. Includes a historical perspective, describes some effects of acid precipitation, and discusses acid rain in the United Kingdom. Contains several experiments that deal with the effects of acid rain on water quality and soil. (TW)

  12. 邻菲啰啉-Fe^3+分光光度法测定食品中的亚硫酸盐%A Spectrometric Method for Sulfite Determination Using the System of Complex of Phenanthroline and Fe~(3+)

    廖文生; 刘中勇; 赵群; 谢思瑶; 伍冠红

    2012-01-01

    Phenanthroline can interact with Fe3+ and Fe2+ to form metal complexes of different colors.Phenanthroline-Fe3+ was changed to phenanthroline-Fe2+ due to the redox reaction between sulfite and Fe3+ with dramatic spectrum changes.Based on this,a spectrometric method for the determination of sulfite was developed.In pH5.00 NaAc-HAc buffer,the addition of sulfite to the phenanthroline-Fe3+ system results in significant absorption increase at 510 nm which is proportional to the concentration of sulfite over the range of 1.08 ×10-6-1.60 ×10-5mol/L with a limit of detection of 1.08×10-7mol/L.The proposed method was applied to determine sulfite in biscuits,the recovery being 92.2%-101.8%.%邻菲啰啉可与Fe3+和Fe2+结合形成不同颜色的金属配合物。利用亚硫酸对Fe3+离子的还原作用,使邻菲啰啉-Fe3+配合物转化为邻菲啰啉-Fe2+,产生显著的光谱变化,据此建立测定亚硫酸盐的光谱分析法。研究结果显示,在pH5.00的乙酸钠-乙酸缓冲溶液中,亚硫酸盐的加入使体系在510 nm处的吸光度显著增强,在一定浓度范围内510nm处吸光度的增加值与亚硫酸盐浓度呈良好线性关系,其线性范围为1.08×10-6-1.60×10-5mol/L,检测限为1.08×10-7mol/L。本方法用于测定饼干中的亚硫酸盐,回收率为92.2%-101.8%。

  13. Synthesis of 1- and 3-11C-labelled L-lactic acid using multi-enzyme catalysis

    The synthesis of 1- and 3-11C-labelled L-lactic acid from the corresponding racemic 1- or 3-11C-labelled alanine using a multi-enzymatic reaction route, is presented. DL-[1-11C]Alanine was synthesised by reacting sodium 1-hydroxy-ethyl sulfite with hydrogen [11C]cyanide, obtained from [11C]carbon dioxide, and ammonia followed by acid hydrolysis. DL-[3-11C]-Alanine was synthesised by a methylation of a glycine derivative, N-(diphenylmethylene)-glycine tert-butyl ester, with [11C]methyl iodide, obtained from [11C]carbon dioxide, and subsequent hydrolysis. The racemic 1- or 3-11C-labelled alanine was then converted to pyruvic acid, by D-amino acid oxidase/catalase and glutamic-pyruvic transaminase, which was directly reduced to L-lactic acid by L-lactic dehydrogenase in a one-pot procedure. The total synthesis time was 40 minutes, counted from release of [11C]carbon dioxide. The decay corrected radiochemical yields were ca. 80% for L-[1-11C]lactic acid, based on hydrogen cyanide, and ca. 60% for L-[3-11C]lactic acid, based on carbon dioxide. The radiochemical purities were higher than 99% analysed by HPLC. (author)

  14. Folic Acid

    ... found naturally in some foods, including leafy vegetables, citrus fruits, beans (legumes), and whole grains. Folic acid ... mcg of folic acid every day for good health. But older adults need to be sure they ...

  15. Contribution to the electrochemical study of corrosion in low-conductivity environments. Application to the study of the behaviour of austenitic stainless steels in concentrated solutions of acetic acid

    As the use of conventional electrochemical methods to study metal and alloy corrosion in concentrated solutions of acetic acid is challenged by difficulties due the low conductivity of these environments, the first part of this research thesis proposes a critical, theoretical and experimental study of these difficulties. It notably evokes the use of electrochemical impedance techniques, the different compensation devices and means of correction of the ohmic voltage drop, and artefacts used during high frequency impedance measurements in lesser conductive solutions. The second part addresses the characterization of the corrosion behaviour of austenitic stainless steels in a concentrated acetic acid at 25 and 95 degrees C. Electrochemical techniques are coupled with analytical methods (solution analysis, sample surface analysis after corrosion tests). The roles of molybdenum as alloying element, of dissolved oxygen, of impurities (sulfites) or of formic acid additions are studied and discussed

  16. Reclamation of acid, toxic coal spoils using wet flue gas desulfurization by-product, fly ash and sewage sludge. Final report

    Kost, D.A.; Vimmerstedt, J.P.; Stehouwer, R.C.

    1997-03-01

    Establishment of vegetation on acid abandoned minelands requires modification of soil physical and chemical conditions. Covering the acid minesoil with topsoil or borrow soil is a common practice but this method may be restricted by availability of borrow soil and cause damage to the borrow site. An alternative approach is to use waste materials as soil amendments. There is a long history of using sewage sludge and fly ash as amendments for acid minesoils. Flue gas desulfurization (FGD) by-products are newer materials that are also promising amendments. Most flue gas sludges are mixtures of Calcium sulfate (CaSO{sub 4}), calcium sulfite (CaSO{sub 3}), calcium carbonate (CaCO{sub 3}), calcium hydroxide [Ca(OH){sub 2}], and fly ash. Some scrubbing processes produce almost pure gypsum (CaSO{sub 4}2H{sub 2}O). The primary purpose of the project is to evaluate two wet FGD by-products for effects on vegetation establishment and surface and ground water quality on an acid minesoil. One by-product from the Conesville, OH power plant (American Electric Power Service Corporation) contains primarily calcium sulfite and fly ash. The other by-product (Mg-gypsum FGD) from an experimental scrubber at the Zimmer power plant (Cincinnati Gas and Electric Company) is primarily gypsum with 4% magnesium hydroxide. These materials were compared with borrow soil and sewage sludge as minesoil amendments. Combinations of each FGD sludge with sewage sludge were also tested. This report summarizes two years of measurements of chemical composition of runoff water, ground water at two depths in the subsoil, soil chemical properties, elemental composition and yield of herbaceous ground cover, and elemental composition, survival and height of trees planted on plots treated with the various amendments. The borrow soil is the control for comparison with the other treatments.

  17. Reclamation of acid, toxic coal spoils using wet flue gas desulfurization by-product, fly ash and sewage sludge. Final report

    Establishment of vegetation on acid abandoned minelands requires modification of soil physical and chemical conditions. Covering the acid minesoil with topsoil or borrow soil is a common practice but this method may be restricted by availability of borrow soil and cause damage to the borrow site. An alternative approach is to use waste materials as soil amendments. There is a long history of using sewage sludge and fly ash as amendments for acid minesoils. Flue gas desulfurization (FGD) by-products are newer materials that are also promising amendments. Most flue gas sludges are mixtures of Calcium sulfate (CaSO4), calcium sulfite (CaSO3), calcium carbonate (CaCO3), calcium hydroxide [Ca(OH)2], and fly ash. Some scrubbing processes produce almost pure gypsum (CaSO42H2O). The primary purpose of the project is to evaluate two wet FGD by-products for effects on vegetation establishment and surface and ground water quality on an acid minesoil. One by-product from the Conesville, OH power plant (American Electric Power Service Corporation) contains primarily calcium sulfite and fly ash. The other by-product (Mg-gypsum FGD) from an experimental scrubber at the Zimmer power plant (Cincinnati Gas and Electric Company) is primarily gypsum with 4% magnesium hydroxide. These materials were compared with borrow soil and sewage sludge as minesoil amendments. Combinations of each FGD sludge with sewage sludge were also tested. This report summarizes two years of measurements of chemical composition of runoff water, ground water at two depths in the subsoil, soil chemical properties, elemental composition and yield of herbaceous ground cover, and elemental composition, survival and height of trees planted on plots treated with the various amendments. The borrow soil is the control for comparison with the other treatments

  18. Formation of haloacetamides during chlorination of dissolved organic nitrogen aspartic acid

    The stability of haloacetamides (HAcAms) such as dichloroacetamide (DCAcAm) and trichloroacetamide (TCAcAm) was studied under different experimental conditions. The yield of HAcAms during aspartic acid (Asp) chlorination was measured at different molar ratio of chlorine atom to nitrogen atom (Cl/N), pH and dissolved organic carbon (DOC) mainly consisted of humic acid (HA) mixture. Ascorbic acid showed a better capacity to prevent the decay of DCAcAm and TCAcAm than the other two dechlorinating agents, thiosulfate and sodium sulfite. Lower Cl/N favored the DCAcAm formation, implying that breakpoint chlorination might minimize its generation. The pH decrease could lower the concentration of DCAcAm but favored dichloroacetonitrile (DCAN) formation. DCAcAm yield was sensitive to the DOC due to higher chlorine consumption caused by HA mixture. Two possible pathways of DCAcAm formation during Asp chlorination were proposed. Asp was an important precursor of DCAN, DCAcAm and dichloroacetic acid (DCAA), and thus removal of Asp before disinfection may be a method to prevent the formation of DCAcAm, DCAN and DCAA.

  19. Formation of haloacetamides during chlorination of dissolved organic nitrogen aspartic acid

    Chu Wenhai, E-mail: 1world1water@tongji.edu.cn [State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai, 200092 (China); Gao Naiyun [State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai, 200092 (China); Deng Yang, E-mail: yang.deng@upr.edu [Department of Civil Engineering and Surveying, University of Puerto Rico, P.O. Box 9041, Mayaguez, Puerto Rico, 00681-9041 (Puerto Rico)

    2010-01-15

    The stability of haloacetamides (HAcAms) such as dichloroacetamide (DCAcAm) and trichloroacetamide (TCAcAm) was studied under different experimental conditions. The yield of HAcAms during aspartic acid (Asp) chlorination was measured at different molar ratio of chlorine atom to nitrogen atom (Cl/N), pH and dissolved organic carbon (DOC) mainly consisted of humic acid (HA) mixture. Ascorbic acid showed a better capacity to prevent the decay of DCAcAm and TCAcAm than the other two dechlorinating agents, thiosulfate and sodium sulfite. Lower Cl/N favored the DCAcAm formation, implying that breakpoint chlorination might minimize its generation. The pH decrease could lower the concentration of DCAcAm but favored dichloroacetonitrile (DCAN) formation. DCAcAm yield was sensitive to the DOC due to higher chlorine consumption caused by HA mixture. Two possible pathways of DCAcAm formation during Asp chlorination were proposed. Asp was an important precursor of DCAN, DCAcAm and dichloroacetic acid (DCAA), and thus removal of Asp before disinfection may be a method to prevent the formation of DCAcAm, DCAN and DCAA.

  20. Phase diagrams for (liquid + liquid) and (liquid + solid) equilibrium of aqueous two-phase system containing {polyvinylpyrrolidone 3500 (PVP3500) + sodium sulfite (Na2SO3) + water} at different temperatures

    Highlights: • LLE of (polyvinylpyrrolidone + sodium sulfite + water) was studied. • The complete phase diagram for PVP3500 + Na2SO3 + H2O was determined at T = 298.15 K. • Binodal data were correlated with two empirical equations. • Tie-lines were fitted to several models including extended NRTL and modified NRTL. • The entropy is driving force for aqueous two-phase formation. - Abstract: The (liquid + liquid) equilibrium (LLE) for the {polyvinylpyrrolidone (PVP3500) + Na2SO3 + H2O} system has been determined experimentally at T = (298.15, 308.15 and 318.15) K. The (liquid + liquid + solid) equilibrium (LLSE) and complete phase diagram of this system were also obtained at T = 298.15 K. The effect of temperature on the binodal curves and the tie-lines for the investigated aqueous two-phase system (ATPS) have been studied. The Merchuk equation and an empirical equation that we proposed in our previous work were used for reproducing the experimental binodal results, and their three fitting parameters were obtained with the temperature dependence expressed in the linear form with (T − T0) K as a variable. Furthermore, the Othmer–Tobias and Bancroft, a temperature dependent Setschenow-type equation and osmotic virial model, the segment-based local composition models (i.e. the extended NRTL (E-NRTL) and modified NRTL (M-NRTL)) were used for the correlation of the (liquid + liquid) phase behavior of the studied system. Also, we estimated plait point, slope and the length of tie-lines at T = (298.15, 308.15 and 318.15) K

  1. Ibotenic acid and thioibotenic acid

    Hermit, Mette B; Greenwood, Jeremy R; Nielsen, Birgitte;

    2004-01-01

    In this study, we have determined and compared the pharmacological profiles of ibotenic acid and its isothiazole analogue thioibotenic acid at native rat ionotropic glutamate (iGlu) receptors and at recombinant rat metabotropic glutamate (mGlu) receptors expressed in mammalian cell lines....... Thioibotenic acid has a distinct pharmacological profile at group III mGlu receptors compared with the closely structurally related ibotenic acid; the former is a potent (low microm) agonist, whereas the latter is inactive. By comparing the conformational energy profiles of ibotenic and thioibotenic acid with...... the conformations preferred by the ligands upon docking to mGlu1 and models of the other mGlu subtypes, we propose that unlike other subtypes, group III mGlu receptor binding sites require a ligand conformation at an energy level which is prohibitively expensive for ibotenic acid, but not for...

  2. [Gastric Acid].

    Ruíz Chávez, R

    1996-01-01

    Gastric acid, a product of parietal cells secretion, full fills multiple biological roles which are absolutely necessary to keep corporal homeostasis. The production of the acid depends upon an effector cellular process represented in the first step by histamine, acetilcholine and gastrin, first messengers of the process. These interact with specific receptors than in sequence activate second messengers -cAMP and the calcium-calmodulin system- which afterwards activate a kinase. An specific protein is then phosphorilated by this enzyme, being the crucial factor that starts the production of acid. Finally, a proton bomb, extrudes the acid towards the gastric lumen. The secretion process mentioned above, is progressive lyactivated in three steps, two of which are stimulators -cephalic and gastric phases- and the other one inhibitor or intestinal phase. These stages are started by mental and neurological phenomena -thought, sight, smell or memory-; by food, drugs or other ingested substances; and by products of digestion. Changes in regulation of acid secretion, in the structure of gastro-duodenal mucosal barrier by a wide spectrum of factors and agents including food, drugs and H. pylori, are the basis of acid-peptic disease, entity in which gastric acid plays a fundamental role. From the therapeutic point of view, so at the theoretical as at the practical levels, t is possible to interfere with the secretion of acid by neutralization of some of the steps of the effector cellular process. An adequate knowledge of the basics related to gastric acid, allows to create strategies for the clinical handling of associated pathology, specifically in relation to peptic acid disease in all of the known clinical forms. PMID:12165790

  3. ACID RAIN

    Acid precipitation has become one of the major environmental problems of this decade. It is a challenge to scientists throughout the world. Researchers from such diverse disciplines as plant pathology, soil science, bacteriology, meteorology and engineering are investigating diff...

  4. Folic Acid

    Full Text Available ... Just a moment, please. You've saved this page It's been added to your dashboard . Folic acid ... Map Premature birth report card Careers Archives Health Topics Pregnancy Before or between pregnancies Nutrition, weight & fitness ...

  5. Folic acid

    ... include leafy vegetables (such as spinach, broccoli, and lettuce), okra, asparagus, fruits (such as bananas, melons, and ... Pyrimethamine (Daraprim)Pyrimethamine (Daraprim) is used to treat parasite infections. Folic acid might decrease the effectiveness of ...

  6. Folic Acid

    Full Text Available ... March of Dimes Premature Birth Report Card Grades Cities, Counties; Focuses on Racial and Ethnic Disparities March ... your baby. Learn how you can get the right amout of folic acid before and during pregnancy ...

  7. Folic Acid

    Full Text Available ... Folic acid Description | Related videos | Most played video E-mail to a friend Please fill in all fields. Please enter a valid e-mail address. Your information: Your recipient's information: Your ...

  8. Okadaic acid

    Danielsen, E Michael; Hansen, Gert H; Severinsen, Mai C K

    2014-01-01

    Okadaic acid (OA) is a polyether fatty acid produced by marine dinoflagellates and the causative agent of diarrhetic shellfish poisoning. The effect of OA on apical endocytosis in the small intestine was studied in organ cultured porcine mucosal explants. Within 0.5-1 h of culture, the toxin caused...... endosomes (TWEEs) occurred unimpeded in the presence of OA, FM condensed in larger subapical structures by 1 h, implying a perturbed endosomal trafficking/maturation. The fluorescent lysosomotropic agent Lysotracker revealed induction of large lysosomal structures by OA. Endocytosis from the brush border...

  9. Mefenamic Acid

    Mefenamic acid comes as a capsule to take by mouth. It is usually taken with food every 6 hours as needed for up to 1 week. Follow ... pain vomit that is bloody or looks like coffee grounds black, tarry, or bloody stools slowed breathing ...

  10. Ascorbic Acid

    Cevi-Bid® ... If you become pregnant while taking ascorbic acid, call your doctor. ... In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call ...

  11. Perfluorooctanoic acid

    P. de Voogt

    2014-01-01

    Perfluorooctanoic acid (PFOA, 335-67-1) is used in fluoropolymer production and firefighting foams and persists in the environment. Human exposure to PFOA is mostly through the diet. PFOA primarily affects the liver and can cause developmental and reproductive toxic effects in test animals.

  12. Stearic Acid

    Young, Jay A.

    2004-01-01

    A chemical laboratory information profile (CLIP) is presented for the chemical, stearic acid. The profile lists the chemical's physical and harmful characteristics, exposure limits, and symptoms of major exposure, for the benefit of teachers and students, who use the chemical in the laboratory.

  13. Hydroxycarboxylic acids and salts

    Kiely, Donald E; Hash, Kirk R; Kramer-Presta, Kylie; Smith, Tyler N

    2015-02-24

    Compositions which inhibit corrosion and alter the physical properties of concrete (admixtures) are prepared from salt mixtures of hydroxycarboxylic acids, carboxylic acids, and nitric acid. The salt mixtures are prepared by neutralizing acid product mixtures from the oxidation of polyols using nitric acid and oxygen as the oxidizing agents. Nitric acid is removed from the hydroxycarboxylic acids by evaporation and diffusion dialysis.

  14. Understanding Acid Rain

    Damonte, Kathleen

    2004-01-01

    The term acid rain describes rain, snow, or fog that is more acidic than normal precipitation. To understand what acid rain is, it is first necessary to know what an acid is. Acids can be defined as substances that produce hydrogen ions (H+), when dissolved in water. Scientists indicate how acidic a substance is by a set of numbers called the pH…

  15. Dehydroabietic acid

    Xiao-Ping Rao

    2009-10-01

    Full Text Available The title compound [systematic name: (1R,4aS,10aR-7-isopropyl-1,4a-dimethyl-1,2,3,4,4a,9,10,10a-octahydrophenanthrene-1-carboxylic acid], C20H28O2, has been isolated from disproportionated rosin which is obtained by isomerizing gum rosin with a Pd-C catalyst.. Two crystallographically independent molecules exist in the asymmetric unit. In each molecule, there are three six-membered rings, which adopt planar, half-chair and chair conformations. The two cyclohexane rings form a trans ring junction with the two methyl groups in axial positions. The crystal structure is stabilized by intermolecular O—H...O hydrogen bonds.

  16. Electrochemical and conversion electron Moessbauer study of corrosion induced by acid rain

    The passivation of low carbon steel was studied in aqueous solution of 0.5M Na2SO4+0.001M NaHSO3 (pH 3.5, 6.5 and 8.5) which can be considered as a model of acid rain. The used conversion electron Moessbauer spectroscopy (CEMS) with the complementary electrochemical investigations proved that the sulfite ions induce pitting corrosion at pH 3.5 and 6.5, while the measurements showed much weaker pitting at pH 8.5. The compositions and thicknesses of the passive films formed during the electrochemical treatments are determined from the CEM spectra. Only γ-FeOOH was found on the surface of the samples at pH 6.5 and 8.5. Nevertheless, at pH 3.5 the sextet belonging to Fe3C appears in the spectra, and also FeSO4.H2O could be detected in low concentration. (orig.)

  17. Retarded acid emulsion

    Fast, C.R.; Rixe, F.H.; Duffield, E.L. Jr.

    1972-08-01

    Compositions for use in acidizing hydrocarbon-bearing formations are described. Retarded acid emulsions of prolonged stability make it possible for the acid in this form to be displaced substantial distances out into the formation before becoming spent. The action of acid emulsions for use in acidizing hydrocarbon-bearing formations is prolonged by employing as the principal emulsifying agent an amine salt of dodecylbenzene sulfonic acid. Acid emulsions employing the amine salt of dodecylbenzene sulfonic acid exhibit greater stability than those employing the free acid. (8 claims)

  18. Acid Lipase Disease

    ... Enhancing Diversity Find People About NINDS NINDS Acid Lipase Disease Information Page Synonym(s): Cholesterol Ester Storage Disease, ... Related NINDS Publications and Information What is Acid Lipase Disease ? Acid lipase disease or deficiency occurs when ...

  19. Plasma amino acids

    Amino acids blood test ... types of methods used to determine the individual amino acid levels in the blood. ... test is done to measure the level of amino acids in the blood. An increased level of a ...

  20. POLYELEOSTEARIC ACID VESICLES

    LI Zichen; XIE Ximng; FAN Qinghua; FANG Yifei

    1992-01-01

    α-Eleostearic acid and β-eleostearic acid formed vesicles in aqueous medium when an ethanol solutionofeleostearic acid was injected rapidly into a vigorously vortexed aqueous phase. Formation of the vesicles was demonstrated by electron microscopic observation and bromothymol blue encapsulation experiments. Polymerizations of the eleostearic acids in the formed vesicles carried out by UV irradiation produced poly-α-eleostearic acid and poly-β-eleostearic acid vesicles.

  1. Acid distribution in phosphoric acid fuel cells

    Okae, I.; Seya, A.; Umemoto, M. [Fuji Electric Co., Ltd., Chiba (Japan)

    1996-12-31

    Electrolyte acid distribution among each component of a cell is determined by capillary force when the cell is not in operation, but the distribution under the current load conditions had not been clear so far. Since the loss of electrolyte acid during operation is inevitable, it is necessary to store enough amount of acid in every cell. But it must be under the level of which the acid disturbs the diffusion of reactive gases. Accordingly to know the actual acid distribution during operation in a cell is very important. In this report, we carried out experiments to clarify the distribution using small single cells.

  2. Metabolic potential of fatty acid oxidation and anaerobic respiration by abundant members of Thaumarchaeota and Thermoplasmata in deep anoxic peat

    Lin, Xueju [Georgia Inst. of Technology, Atlanta, GA (United States); Handley, Kim M. [Univ. of Chicago, IL (United States); Argonne National Lab. (ANL), Argonne, IL (United States); Gilbert, Jack A. [Univ. of Chicago, IL (United States); Argonne National Lab. (ANL), Argonne, IL (United States); Marine Biological Lab., Woods Hole, MA (United States); Zhejiang Univ., Hangzhou (China); Kostka, Joel E. [Georgia Inst. of Technology, Atlanta, GA (United States)

    2015-05-22

    To probe the metabolic potential of abundant Archaea in boreal peats, we reconstructed two near-complete archaeal genomes, affiliated with Thaumarchaeota group 1.1c (bin Fn1, 8% abundance), which was a genomically unrepresented group, and Thermoplasmata (bin Bg1, 26% abundance), from metagenomic data acquired from deep anoxic peat layers. Each of the near-complete genomes encodes the potential to degrade long-chain fatty acids (LCFA) via β-oxidation. Fn1 has the potential to oxidize LCFA either by syntrophic interaction with methanogens or by coupling oxidation with anaerobic respiration using fumarate as a terminal electron acceptor (TEA). Fn1 is the first Thaumarchaeota genome without an identifiable carbon fixation pathway, indicating that this mesophilic phylum encompasses more diverse metabolisms than previously thought. Furthermore, we report genetic evidence suggestive of sulfite and/or organosulfonate reduction by Thermoplasmata Bg1. In deep peat, inorganic TEAs are often depleted to extremely low levels, yet the anaerobic respiration predicted for two abundant archaeal members suggests organic electron acceptors such as fumarate and organosulfonate (enriched in humic substances) may be important for respiration and C mineralization in peatlands.

  3. Structural and Functional Insights from the Metagenome of an Acidic Hot Spring Microbial Planktonic Community in the Colombian Andes

    Jiménez, Diego Javier; Andreote, Fernando Dini; Chaves, Diego; Montaña, José Salvador; Osorio-Forero, Cesar; Junca, Howard; Zambrano, María Mercedes; Baena, Sandra

    2012-01-01

    A taxonomic and annotated functional description of microbial life was deduced from 53 Mb of metagenomic sequence retrieved from a planktonic fraction of the Neotropical high Andean (3,973 meters above sea level) acidic hot spring El Coquito (EC). A classification of unassembled metagenomic reads using different databases showed a high proportion of Gammaproteobacteria and Alphaproteobacteria (in total read affiliation), and through taxonomic affiliation of 16S rRNA gene fragments we observed the presence of Proteobacteria, micro-algae chloroplast and Firmicutes. Reads mapped against the genomes Acidiphilium cryptum JF-5, Legionella pneumophila str. Corby and Acidithiobacillus caldus revealed the presence of transposase-like sequences, potentially involved in horizontal gene transfer. Functional annotation and hierarchical comparison with different datasets obtained by pyrosequencing in different ecosystems showed that the microbial community also contained extensive DNA repair systems, possibly to cope with ultraviolet radiation at such high altitudes. Analysis of genes involved in the nitrogen cycle indicated the presence of dissimilatory nitrate reduction to N2 (narGHI, nirS, norBCDQ and nosZ), associated with Proteobacteria-like sequences. Genes involved in the sulfur cycle (cysDN, cysNC and aprA) indicated adenylsulfate and sulfite production that were affiliated to several bacterial species. In summary, metagenomic sequence data provided insight regarding the structure and possible functions of this hot spring microbial community, describing some groups potentially involved in the nitrogen and sulfur cycling in this environment. PMID:23251687

  4. Structural and functional insights from the metagenome of an acidic hot spring microbial planktonic community in the Colombian Andes.

    Diego Javier Jiménez

    Full Text Available A taxonomic and annotated functional description of microbial life was deduced from 53 Mb of metagenomic sequence retrieved from a planktonic fraction of the Neotropical high Andean (3,973 meters above sea level acidic hot spring El Coquito (EC. A classification of unassembled metagenomic reads using different databases showed a high proportion of Gammaproteobacteria and Alphaproteobacteria (in total read affiliation, and through taxonomic affiliation of 16S rRNA gene fragments we observed the presence of Proteobacteria, micro-algae chloroplast and Firmicutes. Reads mapped against the genomes Acidiphilium cryptum JF-5, Legionella pneumophila str. Corby and Acidithiobacillus caldus revealed the presence of transposase-like sequences, potentially involved in horizontal gene transfer. Functional annotation and hierarchical comparison with different datasets obtained by pyrosequencing in different ecosystems showed that the microbial community also contained extensive DNA repair systems, possibly to cope with ultraviolet radiation at such high altitudes. Analysis of genes involved in the nitrogen cycle indicated the presence of dissimilatory nitrate reduction to N2 (narGHI, nirS, norBCDQ and nosZ, associated with Proteobacteria-like sequences. Genes involved in the sulfur cycle (cysDN, cysNC and aprA indicated adenylsulfate and sulfite production that were affiliated to several bacterial species. In summary, metagenomic sequence data provided insight regarding the structure and possible functions of this hot spring microbial community, describing some groups potentially involved in the nitrogen and sulfur cycling in this environment.

  5. Acid Thunder: Acid Rain and Ancient Mesoamerica

    Kahl, Jonathan D. W.; Berg, Craig A.

    2006-01-01

    Much of Mesoamerica's rich cultural heritage is slowly eroding because of acid rain. Just as water dissolves an Alka-Seltzer tablet, acid rain erodes the limestone surfaces of Mexican archaeological sites at a rate of about one-half millimeter per century (Bravo et al. 2003). A half-millimeter may not seem like much, but at this pace, a few…

  6. Acid Deposition Phenomena

    Acid deposition, commonly known as acid rain, occurs when emissions from the combustion of fossil fuels and other industrial processes undergo complex chemical reactions in the atmosphere and fall to the earth as wet deposition (rain, snow, cloud, fog) or dry deposition (dry particles, gas). Rain and snow are already naturally acidic, but are only considered problematic when less than a ph of 5.0 The main chemical precursors leading to acidic conditions are atmospheric concentrations of sulfur dioxide (SO2) and nitrogen oxides (NOx). When these two compounds react with water, oxygen, and sunlight in the atmosphere, the result is sulfuric (H2SO4) and nitric acids (HNO3), the primary agents of acid deposition which mainly produced from the combustion of fossil fuel and from petroleum refinery. Airborne chemicals can travel long distances from their sources and can therefore affect ecosystems over broad regional scales and in locations far from the sources of emissions. According to the concern of petroleum ministry with the environment and occupational health, in this paper we will discussed the acid deposition phenomena through the following: Types of acidic deposition and its components in the atmosphere Natural and man-made sources of compounds causing the acidic deposition. Chemical reactions causing the acidic deposition phenomenon in the atmosphere. Factors affecting level of acidic deposition in the atmosphere. Impact of acid deposition. Procedures for acidic deposition control in petroleum industry

  7. Discussion of the Analysis Method of Acid Soluble Copper in the Oxide Copper Ore%氧化铜矿中酸溶铜的分析方法探讨

    佡云

    2013-01-01

    The method involves decomposing the sample by treating it with sulfuric acid( 10% ) which con-tained sodium sulfite , and the oxide of copper is dissolved selectively . After filtering , add some bromine to mask arsenic , antimony and etc . Add little sulfuric acid and evaporate to dryness . Salts are dissolved using sulfuric acid and water . Using iodometric method and electro gravimetric method to analysis for compari-son . The text choose 14 production samples , comparing with the two methods , the results are stable and reliable .%试样用含亚硫酸钠的10%硫酸溶液浸取,使铜的氧化物矿物选择溶解,过滤后加入溴素掩蔽砷和锑等金属,补加少量硫酸,蒸干后用硫酸溶解,采用碘量法和电重法对比分析。本文采用十四个生产试样,两种方法对比,结果稳定,可靠。

  8. Catalytic Synthesis Lactobionic Acid

    V.G. Borodina

    2014-07-01

    Full Text Available Gold nanoparticles are obtained, characterized and deposited on the carrier. Conducted catalytic synthesis of lactobionic acid from lactose. Received lactobionic acid identify on the IR spectrum.

  9. Omega-6 Fatty Acids

    ... Some types are found in vegetable oils, including corn, evening primrose seed, safflower, and soybean oils. Other ... ACIDS are as follows:Improving mental development or growth in infants. Adding arachidonic acid (an omega-6 ...

  10. Plasma amino acids

    Plasma amino acids is a screening test done on infants that looks at the amounts of amino ... Laboratory error High or low amounts of individual plasma amino acids must be considered with other information. ...

  11. Omega-3 Fatty Acids

    Omega-3 fatty acids are used together with lifestyle changes (diet, weight-loss, exercise) to reduce the amount ... the blood in people with very high triglycerides. Omega-3 fatty acids are in a class of medications ...

  12. Zoledronic Acid Injection

    ... experience a reaction during the first few days after you receive a dose of zoledronic acid injection. Symptoms ... symptoms may begin during the first 3 days after you receive a dose of zoledronic acid injection and ...

  13. The Acid Rain Reader.

    Stubbs, Harriett S.; And Others

    A topic which is often not sufficiently dealt with in elementary school textbooks is acid rain. This student text is designed to supplement classroom materials on the topic. Discussed are: (1) "Rain"; (2) "Water Cycle"; (3) "Fossil Fuels"; (4) "Air Pollution"; (5) "Superstacks"; (6) "Acid/Neutral/Bases"; (7) "pH Scale"; (8) "Acid Rain"; (9)…

  14. Acid Rain Study Guide.

    Hunger, Carolyn; And Others

    Acid rain is a complex, worldwide environmental problem. This study guide is intended to aid teachers of grades 4-12 to help their students understand what acid rain is, why it is a problem, and what possible solutions exist. The document contains specific sections on: (1) the various terms used in conjunction with acid rain (such as acid…

  15. Immunoglobulin and fatty acids

    2009-01-01

    The present invention relates to a composition comprising 0.1-10 w/w % immunoglobulin (Ig), 4-14 w/w % saturated fatty acids, 4-14 w/w % mono-unsaturated fatty acids and 0-5 w/w % poly-unsaturated fatty acids, wherein the weight percentages are based on the content of dry matter in the composition...

  16. Cleavage of nucleic acids

    Prudent, James R. (Madison, WI); Hall, Jeff G. (Madison, WI); Lyamichev, Victor L. (Madison, WI); Brow, Mary Ann D. (Madison, WI); Dahlberg, James E. (Madison, WI)

    2007-12-11

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

  17. Cleavage of nucleic acids

    Prudent, James R. (Madison, WI); Hall, Jeff G. (Waunakee, WI); Lyamichev, Victor I. (Madison, WI); Brow; Mary Ann D. (Madison, WI); Dahlberg, James E. (Madison, WI)

    2010-11-09

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

  18. Nucleic acid detection compositions

    Prudent, James R. (Madison, WI); Hall, Jeff G. (Madison, WI); Lyamichev, Victor I. (Madison, WI); Brow, Mary Ann (Madison, WI); Dahlberg, James L. (Madison, WI)

    2008-08-05

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

  19. Nucleic acid detection assays

    Prudent, James R.; Hall, Jeff G.; Lyamichev, Victor I.; Brow, Mary Ann; Dahlberg, James E.

    2005-04-05

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

  20. Cleavage of nucleic acids

    Prudent, James R.; Hall, Jeff G.; Lyamichev, Victor I.; Brow, Mary Ann D.; Dahlberg, James E.

    2000-01-01

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

  1. Acidizing carbonate reservoirs with chlorocarboxylic acid salt solutions

    Richardson, E.A.; Scheuerman, R.F.; Templeton, C.C.

    1978-10-31

    A carbonate reservoir is acidized slowly by injecting an aqueous solution of a chlorocarboxylic acid salt so that the rate of the acidization is limited to the rate at which an acid is formed by the hydrolyzing of the chlorocarboxylate ions. The rate at which a chlorocarboxylic acid salt hydrolyzes to form an acid provides the desired rate of acid-release. A more complete acid-base reaction by chloroacetic acid, as compared to formic, acetic, and proprionic, is due to its being a much stronger acid. The pKa of chloroacetic acid is 2.86, whereas that of formic acid is 3.75, and that of acetic acid is 4.75. The pKa of a solution of a weak acid is the pH exhibited when the concentration of undissociated acid equals the concentration of the acid anion. 14 claims.

  2. Acidic Ionic Liquids.

    Amarasekara, Ananda S

    2016-05-25

    Ionic liquid with acidic properties is an important branch in the wide ionic liquid field and the aim of this article is to cover all aspects of these acidic ionic liquids, especially focusing on the developments in the last four years. The structural diversity and synthesis of acidic ionic liquids are discussed in the introduction sections of this review. In addition, an unambiguous classification system for various types of acidic ionic liquids is presented in the introduction. The physical properties including acidity, thermo-physical properties, ionic conductivity, spectroscopy, and computational studies on acidic ionic liquids are covered in the next sections. The final section provides a comprehensive review on applications of acidic ionic liquids in a wide array of fields including catalysis, CO2 fixation, ionogel, electrolyte, fuel-cell, membrane, biomass processing, biodiesel synthesis, desulfurization of gasoline/diesel, metal processing, and metal electrodeposition. PMID:27175515

  3. Nucleic acid detection kits

    Hall, Jeff G.; Lyamichev, Victor I.; Mast, Andrea L.; Brow, Mary Ann; Kwiatkowski, Robert W.; Vavra, Stephanie H.

    2005-03-29

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof. The present invention further relates to methods and devices for the separation of nucleic acid molecules based on charge. The present invention also provides methods for the detection of non-target cleavage products via the formation of a complete and activated protein binding region. The invention further provides sensitive and specific methods for the detection of nucleic acid from various viruses in a sample.

  4. Microorganisms for producing organic acids

    Pfleger, Brian Frederick; Begemann, Matthew Brett

    2014-09-30

    Organic acid-producing microorganisms and methods of using same. The organic acid-producing microorganisms comprise modifications that reduce or ablate AcsA activity or AcsA homolog activity. The modifications increase tolerance of the microorganisms to such organic acids as 3-hydroxypropionic acid, acrylic acid, propionic acid, lactic acid, and others. Further modifications to the microorganisms increase production of such organic acids as 3-hydroxypropionic acid, lactate, and others. Methods of producing such organic acids as 3-hydroxypropionic acid, lactate, and others with the modified microorganisms are provided. Methods of using acsA or homologs thereof as counter-selectable markers are also provided.

  5. Bile acid sequestrants

    Hansen, Morten; Sonne, David P; Knop, Filip K

    2014-01-01

    Bile acids are synthesized in the liver from cholesterol and have traditionally been recognized for their role in absorption of lipids and in cholesterol homeostasis. In recent years, however, bile acids have emerged as metabolic signaling molecules that are involved in the regulation of lipid and...... glucose metabolism, and possibly energy homeostasis, through activation of the bile acid receptors farnesoid X receptor (FXR) and TGR5. Bile acid sequestrants (BASs) constitute a class of drugs that bind bile acids in the intestine to form a nonabsorbable complex resulting in interruption of the...... enterohepatic circulation. This increases bile acid synthesis and consequently reduces serum low-density lipoprotein cholesterol. Also, BASs improve glycemic control in patients with type 2 diabetes. Despite a growing understanding of the impact of BASs on glucose metabolism, the mechanisms behind their glucose...

  6. Docosahexaenoic Acid Neurolipidomics

    Niemoller, Tiffany D.; Bazan, Nicolas G.

    2009-01-01

    Mediator lipidomics is a field of study concerned with the characterization, structural elucidation and bioactivity of lipid derivatives generated by enzymatic activity. Omega-3 fatty acids have beneficial effects for vision, brain function, cardiovascular function, and immune-inflammatory responses. Docosahexaenoic acid [DHA; 22:6(n-3)], the most abundant essential omega-3 fatty acid in the human body, is selectively enriched and avidly retained in the central nervous system as an acyl chain...

  7. Fatty acids and epigenetics

    Burdge, Graham C; Lillycrop, Karen A.

    2014-01-01

    Purpose of review The purpose of this review is to assess the findings of recent studies on the effects of fatty acids on epigenetic process and the role of epigenetics in regulating fatty acid metabolism. Recent findings The DNA methylation status of the Fads2 promoter was increased in the liver of the offspring of mice fed an ?-linolenic acid-enriched diet during pregnancy. In rats, increasing total maternal fat intake during pregnancy and lactation induced persistent hypermethyl...

  8. The acid rain primer

    Acid rain continues to be a major problem in North America, and particularly in eastern Canada. This report introduced the topic of acid rain and discussed its formation, measurement, sources, and geographic distribution. The major sources of sulphur dioxide in Canada are smelting metals, burning coal for electrical power generation, industrial emissions (e.g., pulp and paper, petroleum and aluminum industry), and oil and gas extraction and refining. In Canada, the largest source of nitrogen oxide is the burning of fossil fuels by the transportation sector. Problem areas for acid rain in Canada were identified. The effects of acid rain were examined on lakes and aquatic ecosystems, forests and soils, human-made structures and materials, human health, and on visibility. Acid rain policies and programs were then presented from a historical and current context. Ecosystem recovery from acid rain was discussed with reference to acid rain monitoring, atmospheric response to reductions in acid-causing emissions, and ecosystem recovery of lakes, forests, and aquatic ecosystems. Challenges affecting ecosystem recovery were also presented. These challenges include drought and dry weather, decrease of base cations in precipitation, release of sulphate previously stored in soil, mineralization and immobilization of sulphur/sulphates. Last, the report discussed what still needs to be done to improve the problem of acid rain as well as future concerns. These concerns include loss of base cations from forested watersheds and nitrogen deposition and saturation. 21 refs., 2 tabs., 17 figs

  9. USGS Tracks Acid Rain

    Gordon, John D.; Nilles, Mark A.; Schroder, LeRoy J.

    1995-01-01

    The U.S. Geological Survey (USGS) has been actively studying acid rain for the past 15 years. When scientists learned that acid rain could harm fish, fear of damage to our natural environment from acid rain concerned the American public. Research by USGS scientists and other groups began to show that the processes resulting in acid rain are very complex. Scientists were puzzled by the fact that in some cases it was difficult to demonstrate that the pollution from automobiles and factories was causing streams or lakes to become more acidic. Further experiments showed how the natural ability of many soils to neutralize acids would reduce the effects of acid rain in some locations--at least as long as the neutralizing ability lasted (Young, 1991). The USGS has played a key role in establishing and maintaining the only nationwide network of acid rain monitoring stations. This program is called the National Atmospheric Deposition Program/National Trends Network (NADP/NTN). Each week, at approximately 220 NADP/NTN sites across the country, rain and snow samples are collected for analysis. NADP/NTN site in Montana. The USGS supports about 72 of these sites. The information gained from monitoring the chemistry of our nation's rain and snow is important for testing the results of pollution control laws on acid rain.

  10. Azetidinic amino acids

    Bräuner-Osborne, Hans; Bunch, Lennart; Chopin, Nathalie;

    2005-01-01

    A set of ten azetidinic amino acids, that can be envisioned as C-4 alkyl substituted analogues of trans-2-carboxyazetidine-3-acetic acid (t-CAA) and/or conformationally constrained analogues of (R)- or (S)-glutamic acid (Glu) have been synthesized in a diastereo- and enantiomerically pure form from...... two diastereoisomers that were easily separated and converted in two steps into azetidinic amino acids. Azetidines 35-44 were characterized in binding studies on native ionotropic Glu receptors and in functional assays at cloned metabotropic receptors mGluR1, 2 and 4, representing group I, II and III...

  11. Halogenated fatty acids

    Mu, Huiling; Wesén, Clas; Sundin, Peter

    1997-01-01

    Chlorinated fatty acids have been found to be major contributors to organohalogen compounds in fish, bivalves, jellyfish, and lobster, and they have been indicated to contribute considerably to organohalogens in marine mammals. Brominated fatty acids have been found in marine sponges. Also....... However, a natural production of halogenated fatty acids is also possible. In this paper we summarize the present knowledge of the occurrence of halogenated fatty acids in lipids and suggested ways of their formation. In Part II (Trends Anal. Chem. 16 (1997) 274) we deal with methods of their...

  12. THIN-LAYER SEPARATION OF CITRIC ACID CYCLE INTERMEDIATES, LACTIC ACID, AND THE AMINO ACID TAURINE

    This paper describes a two-dimensional mixed-layer method for separating citric acid cycle intermediates, lactic acid and the amino acid taurine. The method cleanly separates all citric acid cycle intermediates tested, excepting citric acid and isocitric acid. The solvents are in...

  13. Molecular Interaction of Pinic Acid with Sulfuric Acid

    Elm, Jonas; Kurten, Theo; Bilde, Merete;

    2014-01-01

    We investigate the molecular interactions between the semivolatile α-pinene oxidation product pinic acid and sulfuric acid using computational methods. The stepwise Gibbs free energies of formation have been calculated utilizing the M06-2X functional, and the stability of the clusters is evaluated...... from the corresponding ΔG values. The first two additions of sulfuric acid to pinic acid are found to be favorable with ΔG values of -9.06 and -10.41 kcal/mol. Addition of a third sulfuric acid molecule is less favorable and leads to a structural rearrangement forming a bridged sulfuric acid-pinic acid...... without the further possibility for attachment of either sulfuric acid or pinic acid. This suggests that pinic acid cannot be a key species in the first steps in nucleation, but the favorable interactions between sulfuric acid and pinic acid imply that pinic acid can contribute to the subsequent growth of...

  14. Characterization of acid tars

    Acid tars from the processing of petroleum and petrochemicals using sulfuric acid were characterized by gas chromatography/mass spectrometry (GC/MS), inductively coupled plasma/optical emission spectrometry (ICP/OES), differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectrometry, and scanning electron microscopy/energy dispersive X-ray (SEM/EDX) micro-analysis. Leaching of contaminants from the acid tars in 48 h batch tests with distilled water at a liquid-to-solid ratio 10:1 was also studied. GC/MS results show that the samples contained aliphatic hydrocarbons, cyclic hydrocarbons, up to 12 of the 16 USEPA priority polycyclic aromatic hydrocarbons (PAHs), and numerous other organic groups, including organic acids (sulfonic acids, carboxylic acids and aromatic acids), phenyl, nitrile, amide, furans, thiophenes, pyrroles, and phthalates, many of which are toxic. Metals analysis shows that Pb was present in significant concentration. DSC results show different transition peaks in the studied samples, demonstrating their complexity and variability. FTIR analysis further confirmed the presence of the organic groups detected by GC/MS. The SEM/EDX micro-analysis results provided insight on the surface characteristics of the samples and show that contaminants distribution was heterogeneous. The results provide useful data on the composition, complexity, and variability of acid tars; information which hitherto have been scarce in public domain.

  15. Amino Acid Crossword Puzzle

    Sims, Paul A.

    2011-01-01

    Learning the 20 standard amino acids is an essential component of an introductory course in biochemistry. Later in the course, the students study metabolism and learn about various catabolic and anabolic pathways involving amino acids. Learning new material or concepts often is easier if one can connect the new material to what one already knows;…

  16. Science of acid rain

    In this report, the mechanism of forming acid rain in the atmosphere and the process of its fall to ground, the mechanism of withering forests by acid substances, and the process of acidifying lakes and marshes are explained. Moreover, the monitoring networks for acid rain and the countermeasures are described. Acid rain is the pollution phenomena related to all environment, that is, atmosphere, hydrosphere, soilsphere, biosphere and so on, and it is a local environmental pollution problem, and at the same time, an international, global environmental pollution problem. In Japan, acid rain has fallen, but the acidification of lakes and marshes is not clear, and the damage to forests is on small scale. However in East Asia region, the release of sulfur oxides and nitrogen oxides is much, and the increase of the effects of acid rain is expected. It is necessary to devise the measures for preventing the damage due to acid rain. The global monitoring networks of World Meteorological Organization and United Nations Environment Program, and those in Europe, USA and Japan are described. The monitoring of acid rain in Japan is behind that in Europe and USA. (K.I.)

  17. Peptide Nucleic Acid Synthons

    2004-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  18. Peptide Nucleic Acids

    2004-01-01

    A novel class of compounds known as peptide nucleic acids, bind complementary DNA and RNA strands, and generally do so more strongly than the corresponding DNA or RNA strands while exhibiting increased sequence specificity and solubility. The peptide nucleic acids comprise ligands selected from a...

  19. Locked nucleic acid

    Jepsen, Jan Stenvang; Sørensen, Mads D; Wengel, Jesper;

    2004-01-01

    Locked nucleic acid (LNA) is a class of nucleic acid analogs possessing very high affinity and excellent specificity toward complementary DNA and RNA, and LNA oligonucleotides have been applied as antisense molecules both in vitro and in vivo. In this review, we briefly describe the basic...

  20. Peptide Nucleic Acids

    2003-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  1. Peptide Nucleic Acids

    1998-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  2. Peptide Nucleic Acids (PNA)

    2002-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  3. Fatty Acid Biosynthesis IX

    Carey, E. M.; Hansen, Heinz Johs. Max; Dils, R.

    1972-01-01

    # 1. I. [I-14C]Acetate was covalently bound to rabbit mammary gland fatty acid synthetase by enzymic transacylation from [I-14C]acetyl-CoA. Per mole of enzyme 2 moles of acetate were bound to thiol groups and up to I mole of acetate was bound to non-thiol groups. # 2. 2. The acetyl-fatty acid...

  4. Halogenated fatty acids

    Mu, Huiling; Wesén, Clas; Sundin, Peter

    1997-01-01

    . However, a natural production of halogenated fatty acids is also possible. In this paper we summarize the present knowledge of the occurrence of halogenated fatty acids in lipids and suggested ways of their formation. In Part II (Trends Anal. Chem. 16 (1997) 274) we deal with methods of their...

  5. Canadian acid rain policy

    On March 13 of 1991, the Prime Minister of Canada, Brian Mulroney and the President of the United States of America, George Bush, signed an Agreement on Air Quality. This agreement enshrines Principle 21 of the 1972 Stockholm Declaration which states that countries are to ensure that activities within their jurisdiction do not cause damage to the environment of another country. This agreement also includes provisions for controlling acid rain. The Agreement on Air Quality followed years of discussion between the two countries and is a significant milestone in the history of Canadian acid rain policy. This paper begins by describing Canadian acid rain policy and its evolution. The paper also outlines the Canada-United States Air Quality Agreement and the effect of the acid rain provisions on deposition in Canada. Finally, it considers the future work that must be undertaken to further resolve the acid rain problem. 8 refs., 5 figs., 1 tab

  6. Synthesis of aminoaldonic acids

    Jørgensen, Christel Thea

    With the aim of synthesising aminoaldonic acids, two 2-acetamido-2-deoxyaldonolactones with D-galacto (6) and D-arabino (11) configuration were prepared from acetylated sugar formazans in analogy with a known procedure. Empolying the same procedure to acetylated sugar phenylhydrazones gave mixtures...... of 2,5-anhydrides and not the expected 2-acetamido-2-deoxy aldose phenylhydrazones. The acetylated phenylhydrazones were found to eliminate acetic acid when heated in aqueous ethanol and 1-phenylazoalkenes could be isolated by crystallisation. By this method the 17, 20, 23 and 25 were prepared from...... aziridino amides 43 and 51 were reductively cleaved with hydrazine to give 3-amino-2,3-dideoxyhexonhydrazides 83 and 85, which were easily converted into the corresponding lactone 84 and acid 86. The aziridine ring of 43 and 51 was also opened with acetic acid to give the 3-amino-3-deoxyhexonic acids 79 and...

  7. Fusidic acid in dermatology

    Schöfer, Helmut; Simonsen, Lene

    1995-01-01

    Studies on the clinical efficacy of fusidic acid in skin and soft-tissue infections (SSTIs), notably those due to Staphylococcus aureus, are reviewed. Oral fusidic acid (tablets dosed at 250 mg twice daily, or a suspension for paediatric use at 20 mg/kg/day given as two daily doses) has shown good...... efficacy and tolerability. Similarly, plain fusidic acid cream or ointment used two or three times daily in SSTIs such as impetigo are clinically and bacteriologically effective, with minimal adverse events. Combination formulations of fusidic acid with 1% hydrocortisone or 0.1% betamethasone achieve...... excellent results in infected eczema by addressing both inflammation and infection. A new lipid-rich combination formulation provides an extra moisturizing effect. Development of resistance to fusidic acid has remained generally low or short-lived and can be minimized by restricting therapy to no more than...

  8. Sulfuric Acid on Europa

    1999-01-01

    Frozen sulfuric acid on Jupiter's moon Europa is depicted in this image produced from data gathered by NASA's Galileo spacecraft. The brightest areas, where the yellow is most intense, represent regions of high frozen sulfuric acid concentration. Sulfuric acid is found in battery acid and in Earth's acid rain. This image is based on data gathered by Galileo's near infrared mapping spectrometer.Europa's leading hemisphere is toward the bottom right, and there are enhanced concentrations of sulfuric acid in the trailing side of Europa (the upper left side of the image). This is the face of Europa that is struck by sulfur ions coming from Jupiter's innermost moon, Io. The long, narrow features that crisscross Europa also show sulfuric acid that may be from sulfurous material extruded in cracks. Galileo, launched in 1989, has been orbiting Jupiter and its moons since December 1995. JPL manages the Galileo mission for NASA's Office of Space Science, Washington DC. JPL is a division of the California Institute of Technology, Pasadena, CA.

  9. Stomach acid test

    Gastric acid secretion test ... The test is done after you have not eaten for a while so fluid is all that remains in ... injected into your body. This is done to test the ability of the cells in the stomach ...

  10. Difficult Decisions: Acid Rain.

    Miller, John A.; Slesnick, Irwin L.

    1989-01-01

    Discusses some of the contributing factors and chemical reactions involved in the production of acid rain, its effects, and political issues pertaining to who should pay for the clean up. Supplies questions for consideration and discussion. (RT)

  11. Folic acid in diet

    ... green leafy vegetables Dried beans and peas (legumes) Citrus fruits and juices Fortified means that vitamins have ... A.D.A.M. Editorial team. Related MedlinePlus Health Topics Folic Acid Browse the Encyclopedia A.D. ...

  12. Citric acid urine test

    ... usually done while you are on a normal diet. Ask your provider for more information. ... acidosis and a tendency to form calcium kidney stones. The ... acid levels: A high carbohydrate diet Estrogen therapy Vitamin D

  13. Azelaic Acid Topical

    ... pores and by decreasing production of keratin, a natural substance that can lead to the development of ... acid controls acne and rosacea but does not cure these conditions. It may take 4 weeks or ...

  14. Acid rain: An overview

    US Fish and Wildlife Service, Department of the Interior — Summary of the effects of acid rain and related processes, sources, issues, corrective actions, research, current law, potential solutions, political solutions,...

  15. Ethylenediaminetetraacetic acid in endodontics

    Mohammadi, Zahed; Shalavi, Sousan; Jafarzadeh, Hamid

    2013-01-01

    Ethylenediaminetetraacetic acid (EDTA) is a chelating agent can bind to metals via four carboxylate and two amine groups. It is a polyamino carboxylic acid and a colorless, water-soluble solid, which is widely used to dissolve lime scale. It is produced as several salts, notably disodium EDTA and calcium disodium EDTA. EDTA reacts with the calcium ions in dentine and forms soluble calcium chelates. A review of the literature and a discussion of the different indications and considerations for...

  16. 铁-亚硫酸盐配合物体系氧化处理硫酸厂的含砷废水%OXIDATION AND REMOVAL OF ARSENIC-CONTAINING WASTEWATER FROM SULFURIC ACID FACTORY BY IRON-SULFITE COMPLEX SYSTEM

    吉冰冰; 肖玫; 张琳; 骆翠红; 吴峰

    2014-01-01

    研究了铁-亚硫酸盐配合物体系处理实际硫酸厂高浓度含砷废水的工艺与影响条件.结果表明,铁-亚硫酸盐配合物在溶解氧参与下反应产生硫酸自由基,氧化废水中的As(Ⅲ)产生As(Ⅴ),然后升高pH,导致铁形成氢氧化物沉淀,从而使得砷被絮凝沉淀去除.絮凝-氧化-再絮凝的工艺优于直接氧化-絮凝工艺;在pH=3、n(F e(Ⅲ) )/n(As)=1/10、n(亚硫酸钠)/n(As)=5、氧化、絮凝时间均为30 min条件下,直接氧化-絮凝工艺总砷去除率可以达到98.5%;絮凝-氧化-再絮凝的工艺As(Ⅲ)去除率达到99.6%,总砷去除率达到99.9%,处理过后,砷含量由500 mg/L降为2mg/L,很容易通过进一步的吸附处理达到排放标准.

  17. Neutron Nucleic Acid Crystallography.

    Chatake, Toshiyuki

    2016-01-01

    The hydration shells surrounding nucleic acids and hydrogen-bonding networks involving water molecules and nucleic acids are essential interactions for the structural stability and function of nucleic acids. Water molecules in the hydration shells influence various conformations of DNA and RNA by specific hydrogen-bonding networks, which often contribute to the chemical reactivity and molecular recognition of nucleic acids. However, X-ray crystallography could not provide a complete description of structural information with respect to hydrogen bonds. Indeed, X-ray crystallography is a powerful tool for determining the locations of water molecules, i.e., the location of the oxygen atom of H2O; however, it is very difficult to determine the orientation of the water molecules, i.e., the orientation of the two hydrogen atoms of H2O, because X-ray scattering from the hydrogen atom is very small.Neutron crystallography is a specialized tool for determining the positions of hydrogen atoms. Neutrons are not diffracted by electrons, but are diffracted by atomic nuclei; accordingly, neutron scattering lengths of hydrogen and its isotopes are comparable to those of non-hydrogen atoms. Therefore, neutron crystallography can determine both of the locations and orientations of water molecules. This chapter describes the current status of neutron nucleic acid crystallographic research as well as the basic principles of neutron diffraction experiments performed on nucleic acid crystals: materials, crystallization, diffraction experiments, and structure determination. PMID:26227050

  18. Utilization of acid tars

    Frolov, A.F.; Denisova, T.L.; Aminov, A.N.

    1987-01-01

    Freshly produced acid tar (FPAT), obtained as refinery waste in treating petroleum oils with sulfuric acid and oleum, contains 80% or more sulfuric acid. Of such tars, pond acid tars, which contain up to 80% neutral petroleum products and sulfonated resins, are more stable, and have found applications in the production of binders for paving materials. In this article the authors are presenting results obtained in a study of the composition and reactivity of FPAT and its stability in storage in blends with asphalts obtained in deasphalting operations, and the possibility of using the FPAT in road construction has been examined. In this work, wastes were used which were obtained in treating the oils T-750, KhF-12, I-8A, and MS-14. Data on the change in group chemical composition of FPAT are shown, and the acidity, viscosity, needle penetration, and softening point of acid tars obtained from different grades of oils are plotted as functions of the storage time. It is also shown that the fresh and hardened FPATs differ in their solubilities in various solvents.

  19. Fatty Acid Biosynthesis IX

    Carey, E. M.; Hansen, Heinz Johs. Max; Dils, R.

    1972-01-01

    # 1. I. [I-14C]Acetate was covalently bound to rabbit mammary gland fatty acid synthetase by enzymic transacylation from [I-14C]acetyl-CoA. Per mole of enzyme 2 moles of acetate were bound to thiol groups and up to I mole of acetate was bound to non-thiol groups. # 2. 2. The acetyl-fatty acid...... synthetase complex was isolated free from acetyl-CoA. It was rapidly hydrolysed at 30°C, but hydrolysis was greatly diminished at o°C and triacetic lactone synthesis occurred. In the presence of malonyl-CoA and NADPH, all the acetate bound to fatty acid synthetase was incorporated into long-chain fatty acids....... Hydrolysis of bound acetate and incorporation of bound acetate into fatty acids were inhibited to the same extent by guanidine hydrochloride. # 3. 3. Acetate was also covalently bound to fatty acid synthetase by chemical acetylation with [I-14C]acetic anhydride in the absence of CoASH. A total of 60 moles of...

  20. Method for isolating nucleic acids

    Hurt, Jr., Richard Ashley; Elias, Dwayne A.

    2015-09-29

    The current disclosure provides methods and kits for isolating nucleic acid from an environmental sample. The current methods and compositions further provide methods for isolating nucleic acids by reducing adsorption of nucleic acids by charged ions and particles within an environmental sample. The methods of the current disclosure provide methods for isolating nucleic acids by releasing adsorbed nucleic acids from charged particles during the nucleic acid isolation process. The current disclosure facilitates the isolation of nucleic acids of sufficient quality and quantity to enable one of ordinary skill in the art to utilize or analyze the isolated nucleic acids for a wide variety of applications including, sequencing or species population analysis.

  1. Acidification and Acid Rain

    Norton, S. A.; Veselã½, J.

    2003-12-01

    Air pollution by acids has been known as a problem for centuries (Ducros, 1845; Smith, 1872; Camuffo, 1992; Brimblecombe, 1992). Only in the mid-1900s did it become clear that it was a problem for more than just industrially developed areas, and that precipitation quality can affect aquatic resources ( Gorham, 1955). The last three decades of the twentieth century saw tremendous progress in the documentation of the chemistry of the atmosphere, precipitation, and the systems impacted by acid atmospheric deposition. Chronic acidification of ecosystems results in chemical changes to soil and to surface waters and groundwater as a result of reduction of base cation supply or an increase in acid (H+) supply, or both. The most fundamental changes during chronic acidification are an increase in exchangeable H+ or Al3+ (aluminum) in soils, an increase in H+ activity (˜concentration) in water in contact with soil, and a decrease in alkalinity in waters draining watersheds. Water draining from the soil is acidified and has a lower pH (=-log [H+]). As systems acidify, their biotic community changes.Acidic surface waters occur in many parts of the world as a consequence of natural processes and also due to atmospheric deposition of strong acid (e.g., Canada, Jeffries et al. (1986); the United Kingdom, Evans and Monteith (2001); Sweden, Swedish Environmental Protection Board (1986); Finland, Forsius et al. (1990); Norway, Henriksen et al. (1988a); and the United States (USA), Brakke et al. (1988)). Concern over acidification in the temperate regions of the northern hemisphere has been driven by the potential for accelerating natural acidification by pollution of the atmosphere with acidic or acidifying compounds. Atmospheric pollution ( Figure 1) has resulted in an increased flux of acid to and through ecosystems. Depending on the ability of an ecosystem to neutralize the increased flux of acidity, acidification may increase only imperceptibly or be accelerated at a rate that

  2. Acid Rain, pH & Acidity: A Common Misinterpretation.

    Clark, David B.; Thompson, Ronald E.

    1989-01-01

    Illustrates the basis for misleading statements about the relationship between pH and acid content in acid rain. Explains why pH cannot be used as a measure of acidity for rain or any other solution. Suggests that teachers present acidity and pH as two separate and distinct concepts. (RT)

  3. Synthesis and anticonvulsant activity of novel bicyclic acidic amino acids

    Conti, Paola; De Amici, Marco; Joppolo Di Ventimiglia, Samuele;

    2003-01-01

    Bicyclic acidic amino acids (+/-)-6 and (+/-)-7, which are conformationally constrained homologues of glutamic acid, were prepared via a strategy based on a 1,3-dipolar cycloaddition. The new amino acids were tested toward ionotropic and metabotropic glutamate receptor subtypes; both of them...

  4. Amino acids in the sedimentary humic and fulvic acids

    Sardessai, S.

    Humic and fulvic acids isolated from a few sediment samples from Arabian Sea and Bay of Bengal were analysed for total hydrolysable amino acids concentration and their composition. The amono acids content of fulvic acids was higher than in the humic...

  5. EFFECT OF ACIDITY ON ACID-SENSITIVE UV CURING SYSTEM

    Qi-dao Chen; Bing Wu; Xiao-yin Hong

    1999-01-01

    By using diphenyliodonium salts with different counterions as photo acid generators (PAGs), the effect of acidity on ring-opening polymerization of epoxy monomers and polycondensation of polyol with hexamethoxymethyl melamine (HMMM) was studied. The result shows that the rate of ring-opening polymerization is evidently dependent on the acidity of the acid and strong photo-generated acid is required.However, there is a leveling effect in the polycondensation system; if the photo-generated acid is stronger than protonated HMMM, the acidity does not obviously affect the polycondensation rate.

  6. Chemistry and electrochemistry in trifluoroacetic acid. Comparison with acetic acid

    As the trifluoroacetic acid is, with the acetic acid, one of most often used carboxylic acids as solvent, notably in organic chemistry, this research thesis addresses some relatively simple complexing and redox reactions to highlight the peculiar feature of this acid, and to explain its very much different behaviour with respect to acetic acid. The author develops the notion of acidity level in solvents of low dielectric constant. The second part addresses a specific solvent: BF3(CH3COOH)2. The boron trifluoride strengthens the acidity of acetic acid and modifies its chemical and physical-chemical properties. In the third part, the author compares solvent properties of CF3COOH and CH3COOH. Noticed differences explain why the trifluoroacetic acid is a more interesting reaction environment than acetic acid for reactions such as electrophilic substitutions or protein solubilisation

  7. Determination of Sialic Acids by Acidic Ninhydrin Reaction

    Yao,Kenzabroh

    1987-12-01

    Full Text Available A new acidic ninhydrin method for determining free sialic acids is described. The method is based on the reaction of sialic acids with Gaitonde's acid ninhydrin reagent 2 which yields a stable color with an absorption maximum at 470 nm. The standard curve is linear in the range of 5 to 500 nmol of N-acetylneuraminic acid per 0.9 ml of reaction mixture. The reaction was specific only for sialic acids among the various sugars and sugar derivatives examined. Some interference of this method by cysteine, cystine and tryptophan was noted, although their absorption maxima differed from that of sialic acids. The interference by these amino acids was eliminated with the use of a small column of cation-exchange resin. The acidic ninhydrin method provides a simple and rapid method for the determination of free sialic acids in biological materials.

  8. Fatty Acid Desaturases, Polyunsaturated Fatty Acid Regulation, and Biotechnological Advances

    Je Min Lee; Hyungjae Lee; SeokBeom Kang; Woo Jung Park

    2016-01-01

    Polyunsaturated fatty acids (PUFAs) are considered to be critical nutrients to regulate human health and development, and numerous fatty acid desaturases play key roles in synthesizing PUFAs. Given the lack of delta-12 and -15 desaturases and the low levels of conversion to PUFAs, humans must consume some omega-3 and omega-6 fatty acids in their diet. Many studies on fatty acid desaturases as well as PUFAs have shown that fatty acid desaturase genes are closely related to different human phys...

  9. Design and performance testing of a DNA extraction assay for sensitive and reliable quantification of acetic acid bacteria directly in red wine using real time PCR

    Cédric eLONGIN

    2016-06-01

    Full Text Available Although strategies exist to prevent AAB contamination, the increased interest for wines with low sulfite addition leads to greater AAB spoilage. Hence there is a real need for a rapid, specific, sensitive and reliable method for detecting these spoilage bacteria. All these requirements are met by real time Polymerase Chain Reaction (or quantitative PCR; qPCR. Here, we compare existing methods of isolating DNA and their adaptation to a red wine matrix. Two different protocols for isolating DNA and three PCR mix compositions were tested to select the best method. The addition of insoluble polyvinylpolypyrrolidone (PVPP at 1% (v/v during DNA extraction using a protocol succeeded in eliminating PCR inhibitors from red wine. We developed a bacterial internal control which was efficient in avoiding false negative results due to decreases in the efficiency of DNA isolation and/or amplification. The specificity, linearity, repeatability and reproducibility of the method were evaluated. A standard curve was established for the enumeration of AAB inoculated into red wines. The limit of quantification in red wine was 3.7 log AAB/mL and about 2.8 log AAB/mL when the volume of the samples was increased from 1 mL to 10 mL. Thus the DNA extraction method developed in this paper allows sensitive and reliable AAB quantification without underestimation thanks to the presence of an internal control. Moreover, monitoring of both the AAB population and the amount of acetic acid in ethanol medium and red wine highlighted that a minimum about 6.0 log cells/mL of AAB is needed to significantly increase the production of acetic acid leading to spoilage.

  10. Design and Performance Testing of a DNA Extraction Assay for Sensitive and Reliable Quantification of Acetic Acid Bacteria Directly in Red Wine Using Real Time PCR

    Longin, Cédric; Guilloux-Benatier, Michèle; Alexandre, Hervé

    2016-01-01

    Although strategies exist to prevent AAB contamination, the increased interest for wines with low sulfite addition leads to greater AAB spoilage. Hence, there is a real need for a rapid, specific, sensitive, and reliable method for detecting these spoilage bacteria. All these requirements are met by real time Polymerase Chain Reaction (or quantitative PCR; qPCR). Here, we compare existing methods of isolating DNA and their adaptation to a red wine matrix. Two different protocols for isolating DNA and three PCR mix compositions were tested to select the best method. The addition of insoluble polyvinylpolypyrrolidone (PVPP) at 1% (v/v) during DNA extraction using a protocol succeeded in eliminating PCR inhibitors from red wine. We developed a bacterial internal control which was efficient in avoiding false negative results due to decreases in the efficiency of DNA isolation and/or amplification. The specificity, linearity, repeatability, and reproducibility of the method were evaluated. A standard curve was established for the enumeration of AAB inoculated into red wines. The limit of quantification in red wine was 3.7 log AAB/mL and about 2.8 log AAB/mL when the volume of the samples was increased from 1 to 10 mL. Thus, the DNA extraction method developed in this paper allows sensitive and reliable AAB quantification without underestimation thanks to the presence of an internal control. Moreover, monitoring of both the AAB population and the amount of acetic acid in ethanol medium and red wine highlighted that a minimum about 6.0 log cells/mL of AAB is needed to significantly increase the production of acetic acid leading to spoilage. PMID:27313572