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Sample records for tartaric acid citric

  1. Photostabilization of ascorbic acid with citric acid, tartaric acid and boric acid in cream formulations.

    PubMed

    Ahmad, I; Ali Sheraz, M; Ahmed, S; Shad, Z; Vaid, F H M

    2012-06-01

    This study involves the evaluation of the effect of certain stabilizers, that is, citric acid (CT), tartaric acid (TA) and boric acid (BA) on the degradation of ascorbic acid (AH(2) ) in oil-in-water cream formulations exposed to the UV light and stored in the dark. The apparent first-order rate constants (0.34-0.95 × 10(-3) min(-1) in light, 0.38-1.24 × 10(-2) day(-1) in dark) for the degradation reactions in the presence of the stabilizers have been determined. These rate constants have been used to derive the second-order rate constants (0.26-1.45 × 10(-2) M(-1) min(-1) in light, 3.75-8.50 × 10(-3) M(-1) day(-1) in dark) for the interaction of AH(2) and the individual stabilizers. These stabilizers are effective in causing the inhibition of the rate of degradation of AH(2) both in the light and in the dark. The inhibitory effect of the stabilizers is in the order of CT > TA > BA. The rate of degradation of AH(2) in the presence of these stabilizers in the light is about 120 times higher than that in the dark. This could be explained on the basis of the deactivation of AH(2) -excited triplet state by CT and TA and by the inhibition of AH(2) degradation through complex formation with BA. AH(2) leads to the formation of dehydroascorbic acid (A) by chemical and photooxidation in cream formulations. © 2012 The Authors. ICS © 2012 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  2. Chemical speciation and mobilization of copper and zinc in naturally contaminated mine soils with citric and tartaric acids.

    PubMed

    Pérez-Esteban, Javier; Escolástico, Consuelo; Moliner, Ana; Masaguer, Alberto

    2013-01-01

    A one-step extraction procedure and a leaching column experiment were performed to assess the effects of citric and tartaric acids on Cu and Zn mobilization in naturally contaminated mine soils to facilitate assisted phytoextraction. A speciation modeling of the soil solution and the metal fractionation of soils were performed to elucidate the chemical processes that affected metal desorption by organic acids. Different extracting solutions were prepared, all of which contained 0.01 M KNO(3) and different concentrations of organic acids: control without organic acids, 0.5 mM citric, 0.5 mM tartaric, 10 mM citric, 10 mM tartaric, and 5 mM citric +5 mM tartaric. The results of the extraction procedure showed that higher concentrations of organic acids increased metal desorption, and citric acid was more effective at facilitating metal desorption than tartaric acid. Metal desorption was mainly influenced by the decreasing pH and the dissolution of Fe and Mn oxides, not by the formation of soluble metal-organic complexes as was predicted by the speciation modeling. The results of the column study reported that low concentrations of organic acids did not significantly increase metal mobilization and that higher doses were also not able to mobilize Zn. However, 5-10 mM citric acid significantly promoted Cu mobilization (from 1 mg kg(-1) in the control to 42 mg kg(-1) with 10 mM citric acid) and reduced the exchangeable (from 21 to 3 mg kg(-1)) and the Fe and Mn oxides (from 443 to 277 mg kg(-1)) fractions. Citric acid could efficiently facilitate assisted phytoextraction techniques. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Performance, kinetics, and equilibrium of methylene blue adsorption on biochar derived from eucalyptus saw dust modified with citric, tartaric, and acetic acids.

    PubMed

    Sun, Lei; Chen, Dongmei; Wan, Shungang; Yu, Zebin

    2015-12-01

    Biochar derived from eucalyptus saw dust modified with citric, tartaric, and acetic acids at low temperatures was utilized as adsorbent to remove methylene blue (MB) from aqueous solutions. Fourier transform infrared spectroscopy analysis showed that the carboxyl group was introduced on the biochar surface. Adsorption experiment data indicated that eucalyptus saw dust modified with citric acid showed higher MB adsorption efficiency than that modified with tartaric and acetic acids. Pseudo-second-order kinetics was the most suitable model for describing MB adsorption on biochar compared with pseudo-first-order, Elovich, and intraparticle diffusion models. The calculated values of ΔG(0) and ΔH(0) indicated the spontaneous and endothermic nature of the adsorption process. MB adsorption on biochar followed the Langmuir isotherm. The maximum adsorption capacities for eucalyptus saw dust modified with citric, tartaric, and acetic acids were 178.57, 99.01, and 29.94 mg g(-1), respectively, at 35°C. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. 21 CFR 184.1099 - Tartaric acid.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Tartaric acid. 184.1099 Section 184.1099 Food and... Substances Affirmed as GRAS § 184.1099 Tartaric acid. (a) Food grade tartaric acid (C4H6O6, CAS Reg. No. 87-69-4) has the l configuration. The l form of tartaric acid is dextrorotatory in solution and is also...

  5. Citric acid urine test

    MedlinePlus

    Urine - citric acid test; Renal tubular acidosis - citric acid test; Kidney stones - citric acid test; Urolithiasis - citric acid test ... No special preparation is necessary for this test. But the results ... test is usually done while you are on a normal diet. Ask your ...

  6. 21 CFR 582.6099 - Tartaric acid.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Tartaric acid. 582.6099 Section 582.6099 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... acid. (a) Product. Tartaric acid. (b) Conditions of use. This substance is generally recognized as safe...

  7. 21 CFR 582.6099 - Tartaric acid.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Tartaric acid. 582.6099 Section 582.6099 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... acid. (a) Product. Tartaric acid. (b) Conditions of use. This substance is generally recognized as safe...

  8. 21 CFR 184.1099 - Tartaric acid.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Tartaric acid. 184.1099 Section 184.1099 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN..., crystalline powder. It is odorless and has an acid taste. It is obtained as a byproduct of wine manufacture...

  9. INTERACTION OF AQUEOUS SOLUTIONS OF CHLORINE WITH MALIC ACID, TARTARIC ACID, AND VARIOUS FRUIT JUICES, A SOURCE OF MUTAGENS

    EPA Science Inventory

    The interactions of aqueous solutions of chlorine with some fruit acids (citric acid, DL-malic acid, and L-tartaric acid) at different pH values were studied. iethyl ether extraction followed by GC/MS analysis indicated that a number of mutagens (certain chlorinated propanones an...

  10. Towards Tartaric-Acid-Derived Asymmetric Organocatalysts

    PubMed Central

    Gratzer, Katharina; Gururaja, Guddeangadi N; Waser, Mario

    2013-01-01

    Tartaric acid is one of the most prominent naturally occurring chiral compounds. Whereas its application in the production of chiral ligands for metal-catalysed reactions has been exhaustively investigated, its potential to provide new organocatalysts has been less extensively explored. Nevertheless, some impressive results, such as the use of TADDOLs as chiral H-bonding catalysts or of tartrate-derived asymmetric quaternary ammonium salt catalysts, have been reported over the last decade. The goal of this article is to provide a representative overview of the potential and the limitations of tartaric acid or TADDOLs in the creation of new organocatalysts and to highlight some of the most spectacular applications of these catalysts, as well as to summarize case studies in which other classes of chiral backbones were better suited. PMID:24194674

  11. Rapid determination of tartaric acid in wines.

    PubMed

    Bastos, Sandra S T; Tafulo, Paula A R; Queirós, Raquel B; Matos, Cristina D; Sales, M Goreti F

    2009-08-01

    A flow-spectrophotometric method is proposed for the routine determination of tartaric acid in wines. The reaction between tartaric acid and vanadate in acetic media is carried out in flowing conditions and the subsequent colored complex is monitored at 475 nm. The stability of the complex and the corresponding formation constant are presented. The effect of wavelength and pH was evaluated by batch experiments. The selected conditions were transposed to a flow-injection analytical system. Optimization of several flow parameters such as reactor lengths, flow-rate and injection volume was carried out. Using optimized conditions, a linear behavior was observed up to 1000 microg mL(-1) tartaric acid, with a molar extinction coefficient of 450 L mg(-1) cm(-1) and +/- 1 % repeatability. Sample throughput was 25 samples per hour. The flow-spectrophotometric method was satisfactorily applied to the quantification of TA in wines from different sources. Its accuracy was confirmed by statistical comparison to the conventional Rebelein procedure and to a certified analytical method carried out in a routine laboratory.

  12. Thoron-tartaric acid systems for spectrophotometric determination of thorium

    USGS Publications Warehouse

    Grimaldi, F.S.; Fletcher, M.H.

    1956-01-01

    Thoron is commonly used for the spectrophotometric determination of thorium. An undesirable feature of its use is its high sensitivity to zirconium. This study describes the use of tartaric acid as a masking reagent for zirconium. Three tartaric acid-thoron systems, developed for the determination of thorium, differ with respect to the concentrations of thoron and tartaric acid. Mesotartaric acid, used in one of the systems, is most effective in masking zirconium. The behavior of rarer elements, usually associated with thorium ores, is determined in two systems, and a dilution method is described for the direct determination of thorium in monazite concentrates.

  13. 21 CFR 184.1033 - Citric acid.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Citric acid. 184.1033 Section 184.1033 Food and... Substances Affirmed as GRAS § 184.1033 Citric acid. (a) Citric acid (C6H8O7, CAS Reg. No. 77-92-9) is the... mole of water per mole of citric acid. Citric acid may be produced by recovery from sources such as...

  14. 21 CFR 184.1033 - Citric acid.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Citric acid. 184.1033 Section 184.1033 Food and... Substances Affirmed as GRAS § 184.1033 Citric acid. (a) Citric acid (C6H8O7, CAS Reg. No. 77-92-9) is the... mole of water per mole of citric acid. Citric acid may be produced by recovery from sources such as...

  15. 21 CFR 184.1033 - Citric acid.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Citric acid. 184.1033 Section 184.1033 Food and... Substances Affirmed as GRAS § 184.1033 Citric acid. (a) Citric acid (C6H8O7, CAS Reg. No. 77-92-9) is the... mole of water per mole of citric acid. Citric acid may be produced by recovery from sources such as...

  16. 21 CFR 184.1033 - Citric acid.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Citric acid. 184.1033 Section 184.1033 Food and....1033 Citric acid. (a) Citric acid (C6H8O7, CAS Reg. No. 77-92-9) is the compound 2-hydroxy-1,2,3... crystals or a white powder and may be anhydrous or contain one mole of water per mole of citric acid...

  17. 21 CFR 582.1033 - Citric acid.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Citric acid. 582.1033 Section 582.1033 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1033 Citric acid. (a) Product. Citric acid. (b) Conditions of use. This substance is generally...

  18. 21 CFR 582.6033 - Citric acid.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Citric acid. 582.6033 Section 582.6033 Food and..., FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Sequestrants 2 § 582.6033 Citric acid. (a) Product. Citric acid. 2 For the purpose of this subpart, no attempt has been made to...

  19. 21 CFR 582.6033 - Citric acid.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Citric acid. 582.6033 Section 582.6033 Food and..., FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Sequestrants 2 § 582.6033 Citric acid. (a) Product. Citric acid. 2 For the purpose of this subpart, no attempt has been made to...

  20. 21 CFR 582.6033 - Citric acid.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Citric acid. 582.6033 Section 582.6033 Food and..., FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Sequestrants 2 § 582.6033 Citric acid. (a) Product. Citric acid. 2 For the purpose of this subpart, no attempt has been made to...

  1. 21 CFR 582.1033 - Citric acid.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Citric acid. 582.1033 Section 582.1033 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1033 Citric acid. (a) Product. Citric acid. (b) Conditions of use. This substance is generally...

  2. 21 CFR 582.6033 - Citric acid.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Citric acid. 582.6033 Section 582.6033 Food and..., FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Sequestrants 2 § 582.6033 Citric acid. (a) Product. Citric acid. 2 For the purpose of this subpart, no attempt has been made to...

  3. 21 CFR 582.1033 - Citric acid.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Citric acid. 582.1033 Section 582.1033 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1033 Citric acid. (a) Product. Citric acid. (b) Conditions of use. This substance is generally...

  4. 21 CFR 582.1033 - Citric acid.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Citric acid. 582.1033 Section 582.1033 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1033 Citric acid. (a) Product. Citric acid. (b) Conditions of use. This substance is generally...

  5. 21 CFR 582.6033 - Citric acid.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Citric acid. 582.6033 Section 582.6033 Food and..., FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Sequestrants 2 § 582.6033 Citric acid. (a) Product. Citric acid. 2 For the purpose of this subpart, no attempt has been made to...

  6. Role of tartaric and malic acids in wine oxidation.

    PubMed

    Danilewicz, John C

    2014-06-04

    Tartaric acid determines the reduction potential of the Fe(III)/Fe(II) redox couple. Therefore, it is proposed that it determines the ability of Fe to catalyze wine oxidation. The importance of tartaric acid was demonstrated by comparing the aerial oxidation of 4-methylcatechol (4-MeC) in model wine made up with tartaric and acetic acids at pH 3.6. Acetic acid, as a weaker Fe(III) ligand, should raise the reduction potential of the Fe couple. 4-MeC was oxidized in both systems, but the mechanisms were found to differ. Fe(II) readily reduced oxygen in tartrate model wine, but Fe(III) alone failed to oxidize the catechol, requiring sulfite assistance. In acetate model wine the reverse was found to operate. These observations should have broad application to model systems designed to study the oxidative process in foods and other beverages. Consideration should be given to the reduction potential of metal couples by the inclusion of appropriate ligands.

  7. Citric Acid Passivation of Stainless Steel

    NASA Technical Reports Server (NTRS)

    Yasensky, David; Reali, John; Larson, Chris; Carl, Chad

    2009-01-01

    Passivation is a process for cleaning and providing corrosion protection for stainless steel. Currently, on Kennedy Space Center (KSC), only parts passivated with nitric acid are acceptable for use. KSC disposes of approximately 125gal of concentrated nitric acid per year, and receives many parts from vendors who must also dispose of used nitric acid. Unfortunately, nitric acid presents health and environmental hazards. As a result, several recent industry studies have examined citric acid as an alternative. Implementing a citric acid-based passivation procedure would improve the health and environmental safety aspects of passivation process. However although there is a lack of published studies that conclusively prove citric acid is a technically sound passivation agent. In 2007, NASA's KSC Materials Advisory Working Group requested the evaluation of citric acid in place of nitric acid for passivation of parts at KSC. United Space Alliance Materials & Processes engineers have developed a three-phase test plan to evaluate citric acid as an alternative to nitric acid on three stainless steels commonly used at KSC: UNS S30400, S41000, and S17400. Phases 1 and 2 will produce an optimized citric acid treatment based on results from atmospheric exposure at NASA's Beach Corrosion Facility. Phase 3 will compare the optimized solution(s) with nitric acid treatments. If the results indicate that citric acid passivates as well or better than nitric acid, NASA intends to approve this method for parts used at the Kennedy Space Center.

  8. Citraturic response to oral citric acid load

    NASA Technical Reports Server (NTRS)

    Sakhaee, K.; Alpern, R.; Poindexter, J.; Pak, C. Y.

    1992-01-01

    It is possible that some orally administered citrate may appear in urine by escaping oxidation in vivo. To determine whether this mechanism contributes to the citraturic response to potassium citrate, we measured serum and urinary citrate for 4 hours after a single oral load of citric acid (40 mEq.) in 6 normal subjects. Since citric acid does not alter acid-base balance, the effect of absorbed citrate could be isolated from that of alkali load. Serum citrate concentration increased significantly (p less than 0.05) 30 minutes after a single oral dose of citric acid and remained significantly elevated for 3 hours after citric acid load. Commensurate with this change, urinary citrate excretion peaked at 2 hours and gradually decreased during the next 2 hours after citric acid load. In contrast, serum and urinary citrate remained unaltered following the control load (no drug). Differences of the citratemic and citraturic effects between phases were significant (p less than 0.05) at 2 and 3 hours. Urinary pH, carbon dioxide pressure, bicarbonate, total carbon dioxide and ammonium did not change at any time after citric acid load, and did not differ between the 2 phases. No significant difference was noted in serum electrolytes, arterialized venous pH and carbon dioxide pressure at any time after citric acid load and between the 2 phases. Thus, the citraturic and citratemic effects of oral citric acid are largely accountable by provision of absorbed citrate, which has escaped in vivo degradation.

  9. Citric Acid Alternative to Nitric Acid Passivation

    NASA Technical Reports Server (NTRS)

    Lewis, Pattie L. (Compiler)

    2013-01-01

    The Ground Systems Development and Operations GSDO) Program at NASA John F. Kennedy Space Center (KSC) has the primary objective of modernizing and transforming the launch and range complex at KSC to benefit current and future NASA programs along with other emerging users. Described as the launch support and infrastructure modernization program in the NASA Authorization Act of 2010, the GSDO Program will develop and implement shared infrastructure and process improvements to provide more flexible, affordable, and responsive capabilities to a multi-user community. In support of the GSDO Program, the purpose of this project is to demonstratevalidate citric acid as a passivation agent for stainless steel. Successful completion of this project will result in citric acid being qualified for use as an environmentally preferable alternative to nitric acid for passivation of stainless steel alloys in NASA and DoD applications.

  10. 21 CFR 184.1033 - Citric acid.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... lemon or pineapple juice; by mycological fermentation using Candida spp., described in §§ 173.160 and... for the recovery of citric acid from Aspergillus niger fermentation liquor. (b) The ingredient meets...

  11. Four Structures of Tartaric Acid Revealed in the Gas Phase

    NASA Astrophysics Data System (ADS)

    Cortijo, Vanessa; Díez, Verónica; Alonso, Elena R.; Mata, Santiago; Alonso, José L.

    2017-06-01

    The tartaric acid, one of the most important organic compounds, has been transferred into the gas phase by laser ablation of its natural crystalline form (m.p.174°C) and probed in a supersonic expansion by chirped-pulse Fourier transform microwave spectroscopy (CP-FTMW). Four stable structures, two with an extended (trans) disposition of the carbon chain and two with a bent (gauche) disposition, have been unequivocally identified on the basis of the experimental rotational constants in conjunction with ab initio predictions. The intramolecular interactions that govern the conformational preferences are dominated by cooperative O-H...O=C type and O-H?O hydrogen bonds extended along the entire molecule. The observation of only μc- type spectra for one "trans" and one "gauche" conformers, support the existence of a C2 symmetry for each structure.

  12. Metabolism of hydroxycinnamic acids and their tartaric acid esters by Brettanomyces and Pediococcus in red wines.

    USDA-ARS?s Scientific Manuscript database

    Caffeic, p-coumaric, and ferulic acids and their corresponding tartaric acid esters (caftaric, coutaric, and fertaric, respectively) are found in wines in varying concentrations. While Brettanomyces and Pediococcus can utilize the free acids, it is not known whether they can metabolize the correspon...

  13. Enhancement of nitric oxide release and hemocompatibility by surface chirality of D-tartaric acid grafting

    NASA Astrophysics Data System (ADS)

    Han, Honghong; Wang, Ke; Fan, Yonghong; Pan, Xiaxin; Huang, Nan; Weng, Yajun

    2017-12-01

    Nitric Oxide (NO) generation from endogenous NO-donors catalyzed by diselenide modified biomaterials has been reported. Here we reported surface chirality by L-tartaric acid and D-tartaric acid grafting on the outermost showed a significant impact on diselenide modified biomaterials, which modulated protein adsorption, NO release and anti-platelet adhesion properties. D-tartaric acid grafted surface showed more blood protein adsorption than that of L-surfaces by QCM analysis, however, ELISA analysis disclosed less fibrinogen denatured on the D surfaces. Due to the surface ratio of selenium decreasing, NO release catalyzed by L-tartaric acid grafting on the outermost significantly decreased in comparison to that of only selenocystamine immobilized surfaces. While NO release catalyzed by D-tartaric acid grafting on the outermost didn't decrease and was similar with that of selenocystamine immobilized surfaces. Surface chirality combined with NO release had synergetic effects on platelet adhesion, and it showed the lowest number of platelets adhered on the D-tartaric acid grafted surfaces. Thus surface chirality from D-tartaric acid grafting enhanced hemocompatibility of the surface in this study. Our work provides new insights into engineering novel blood contacting biomaterials by taking into account surface chirality.

  14. Utilization of citric acid in wood bonding

    USDA-ARS?s Scientific Manuscript database

    Citric acid (CA) is a weak organic acid. It exists most notably in citrus fruits so that it is named likewise. As a commodity chemical, CA is produced on a large scale by fermentation. In this chapter, we first briefly review the applied research and methods for commercial production of CA. Then we ...

  15. l-Tartaric acid synthesis from vitamin C in higher plants

    PubMed Central

    DeBolt, Seth; Cook, Douglas R.; Ford, Christopher M.

    2006-01-01

    The biosynthetic pathway of l-tartaric acid, the form most commonly encountered in nature, and its catabolic ties to vitamin C, remain a challenge to plant scientists. Vitamin C and l-tartaric acid are plant-derived metabolites with intrinsic human value. In contrast to most fruits during development, grapes accumulate l-tartaric acid, which remains within the berry throughout ripening. Berry taste and the organoleptic properties and aging potential of wines are intimately linked to levels of l-tartaric acid present in the fruit, and those added during vinification. Elucidation of the reactions relating l-tartaric acid to vitamin C catabolism in the Vitaceae showed that they proceed via the oxidation of l-idonic acid, the proposed rate-limiting step in the pathway. Here we report the use of transcript and metabolite profiling to identify candidate cDNAs from genes expressed at developmental times and in tissues appropriate for l-tartaric acid biosynthesis in grape berries. Enzymological analyses of one candidate confirmed its activity in the proposed rate-limiting step of the direct pathway from vitamin C to tartaric acid in higher plants. Surveying organic acid content in Vitis and related genera, we have identified a non-tartrate-forming species in which this gene is deleted. This species accumulates in excess of three times the levels of vitamin C than comparably ripe berries of tartrate-accumulating species, suggesting that modulation of tartaric acid biosynthesis may provide a rational basis for the production of grapes rich in vitamin C. PMID:16567629

  16. Effect of propionic acid on citric acid fermentation in an integrated citric acid-methane fermentation process.

    PubMed

    Xu, Jian; Bao, Jia-Wei; Su, Xian-Feng; Zhang, Hong-Jian; Zeng, Xin; Tang, Lei; Wang, Ke; Zhang, Jian-Hua; Chen, Xu-Sheng; Mao, Zhong-Gui

    2016-03-01

    In this study, an integrated citric acid-methane fermentation process was established to solve the problem of wastewater treatment in citric acid production. Citric acid wastewater was treated through anaerobic digestion and then the anaerobic digestion effluent (ADE) was further treated and recycled for the next batch citric acid fermentation. This process could eliminate wastewater discharge and reduce water resource consumption. Propionic acid was found in the ADE and its concentration continually increased in recycling. Effect of propionic acid on citric acid fermentation was investigated, and results indicated that influence of propionic acid on citric acid fermentation was contributed to the undissociated form. Citric acid fermentation was inhibited when the concentration of propionic acid was above 2, 4, and 6 mM in initial pH 4.0, 4.5 and, 5.0, respectively. However, low concentration of propionic acid could promote isomaltase activity which converted more isomaltose to available sugar, thereby increasing citric acid production. High concentration of propionic acid could influence the vitality of cell and prolong the lag phase, causing large amount of glucose still remaining in medium at the end of fermentation and decreasing citric acid production.

  17. Crosslinking of agarose bioplastic using citric acid.

    PubMed

    Awadhiya, Ankur; Kumar, David; Verma, Vivek

    2016-10-20

    We report chemical crosslinking of agarose bioplastic using citric acid. Crosslinking was confirmed using Fourier transform infrared (FTIR) spectroscopy. The effects of crosslinking on the tensile strength, swelling, thermal stability, and degradability of the bioplastic were studied in detail. The tensile strength of the bioplastic films increased from 25.1MPa for control films up to a maximum of 52.7MPa for citric acid crosslinked films. At 37°C, the amount of water absorbed by crosslinked agarose bioplastic was only 11.5% of the amount absorbed by non-crosslinked controls. Thermogravimetric results showed that the crosslinked samples retain greater mass at high temperature (>450°C) than control samples. Moreover, while the crosslinked films were completely degradable, the rate of degradation was lower compared to non-crosslinked controls. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. The thoron-tartaric acid systems for the spectrophotometric determination of thorium

    USGS Publications Warehouse

    Grimaldi, F.S.; Fletcher, Mary H.

    1955-01-01

    Thoron is popularly used for the spectrophotometric determination of thorium.  An undesirable feature of its use is the high sensitivity of the reagent toward zirconium. This study describes the use of tartaric acid as a masking reagent for zirconium. Three tartaric acid-thoron systems, developed for the determination of thorium, differ with respect to the concentrations of thoron and tartaric acid. Mesotataric acid, used in one of the systems, is found to be most effective in masking zirconium. The behavior of various rarer elements, usually found associated with thorium ores, is determined in two of the systems, and a dilution method is described for the direct determination of thorium in monazite concentrates.

  19. Physical and structural characterisation of starch/polyester blends with tartaric acid.

    PubMed

    Olivato, J B; Müller, C M O; Carvalho, G M; Yamashita, F; Grossmann, M V E

    2014-06-01

    Starch/PBAT blends were produced by reactive extrusion with tartaric acid (TA) as an additive. The effects of TA, glycerol and starch+PBAT on the mechanical, optical and structural properties of the films were evaluated, with formulations based in a constrained mixture design. Tartaric acid acts as a compatibiliser and promotes the acid hydrolysis of starch chains. These two functions explain the observed film resistance and opacity. TA reduced the weight loss in water. Scanning electron microscopy (SEM) images showed that TA reduces the interfacial tension between the polymeric phases, resulting in more homogeneous films. Nuclear magnetic resonance ((13)C CPMAS) and Fourier transform infrared spectroscopy (FT-IR) suggest that tartaric acid is able to react with the hydroxyl groups of the starch by esterification/transesterification reactions, confirming its role as a compatibiliser. The addition of TA results in materials with better properties that are suitable for use in food packaging. Published by Elsevier B.V.

  20. Effect of acetic acid on citric acid fermentation in an integrated citric acid-methane fermentation process.

    PubMed

    Xu, Jian; Chen, Yang-Qiu; Zhang, Hong-Jian; Tang, Lei; Wang, Ke; Zhang, Jian-Hua; Chen, Xu-Sheng; Mao, Zhong-Gui

    2014-09-01

    An integrated citric acid-methane fermentation process was proposed to solve the problem of extraction wastewater in citric acid fermentation process. Extraction wastewater was treated by anaerobic digestion and then recycled for the next batch of citric acid fermentation to eliminate wastewater discharge and reduce water resource consumption. Acetic acid as an intermediate product of methane fermentation was present in anaerobic digestion effluent. In this study, the effect of acetic acid on citric acid fermentation was investigated and results showed that lower concentration of acetic acid could promote Aspergillus niger growth and citric acid production. 5-Cyano-2,3-ditolyl tetrazolium chloride (CTC) staining was used to quantify the activity of A. niger cells, and the results suggested that when acetic acid concentration was above 8 mM at initial pH 4.5, the morphology of A. niger became uneven and the part of the cells' activity was significantly reduced, thereby resulting in deceasing of citric acid production. Effects of acetic acid on citric acid fermentation, as influenced by initial pH and cell number in inocula, were also examined. The result indicated that inhibition by acetic acid increased as initial pH declined and was rarely influenced by cell number in inocula.

  1. Germanium oxide removal by citric acid and thiol passivation from citric acid-terminated Ge(100).

    PubMed

    Collins, Gillian; Aureau, Damien; Holmes, Justin D; Etcheberry, Arnaud; O'Dwyer, Colm

    2014-12-02

    Many applications of germanium (Ge) are underpinned by effective oxide removal and surface passivation. This important surface treatment step often requires H-X (X = Cl, Br, I) or HF etchants. Here, we show that aqueous citric acid solutions are effective in the removal of GeOx. The stability of citric acid-treated Ge(100) is compared to HF and HCl treated surfaces and analyzed by X-ray photoelectron spectroscopy. Further Ge surface passivation was investigated by thiolation using alkane monothiols and dithiols. The organic passivation layers show good stability with no oxide regrowth observed after 3 days of ambient exposure.

  2. Highly Selective Deoxydehydration of Tartaric Acid over Supported and Unsupported Rhenium Catalysts with Modified Acidities.

    PubMed

    Li, Xiukai; Zhang, Yugen

    2016-10-06

    The deoxydehydration (DODH) of sugar acids to industrially important carboxylic acids is a very attractive topic. Oxorhenium complexes are the most-often employed DODH catalysts. Because of the acidity of the rhenium catalysts, the DODH products of sugar acids were usually in the form of mixture of free carboxylic acids and esters. Herein, we demonstrate strategies for the selective DODH of sugar acids to free carboxylic acids by tuning the Lewis acidity or the Brønsted acidity of the rhenium-based catalysts. Starting from tartaric acid, up to 97 % yield of free maleic acid was achieved. Based on our strategies, functional polymer immobilized heterogeneous rhenium catalysts were also developed for the selective DODH conversion of sugar acids. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Quantitative analyses of tartaric acid based on terahertz time domain spectroscopy

    NASA Astrophysics Data System (ADS)

    Cao, Binghua; Fan, Mengbao

    2010-10-01

    Terahertz wave is the electromagnetic spectrum situated between microwave and infrared wave. Quantitative analysis based on terahertz spectroscopy is very important for the application of terahertz techniques. But how to realize it is still under study. L-tartaric acid is widely used as acidulant in beverage, and other food, such as soft drinks, wine, candy, bread and some colloidal sweetmeats. In this paper, terahertz time-domain spectroscopy is applied to quantify the tartaric acid. Two methods are employed to process the terahertz spectra of different samples with different content of tartaric acid. The first one is linear regression combining correlation analysis. The second is partial least square (PLS), in which the absorption spectra in the 0.8-1.4THz region are used to quantify the tartaric acid. To compare the performance of these two principles, the relative error of the two methods is analyzed. For this experiment, the first method does better than the second one. But the first method is suitable for the quantitative analysis of materials which has obvious terahertz absorption peaks, while for material which has no obvious terahertz absorption peaks, the second one is more appropriate.

  4. Spectra investigation on surface characteristics of graphene oxide nanosheets treated with tartaric, malic and oxalic acids.

    PubMed

    Teng, Xiyao; Yan, Manqing; Bi, Hong

    2014-01-24

    The surface characteristics of graphene oxide nanosheets (GO) treated respectively with tartaric acid, malic acid and oxalic acid, have been investigated by mainly using optical spectroscopic methods including Fourier transform infrared spectroscopy (FT-IR), Ultraviolet-visible (UV-Vis) absorption and Raman spectroscopy. Additionally, the electrochemical property of the products has also been studied. The data revealed that oxygen-containing groups such as OH, COOH and CO on the GO surface have been almost removed and thus reduced graphene oxide nanosheets (RGN) were obtained. Interestingly, the number of sp(2) domains of RGN increases as treated by tartaric acidacidacid whereas the steric hindrance (SH) decreases and the ionization constant (IC) differs among these three acids. Furthermore, the specific capacitances (Cs) of GO have been greatly promoted from 2.4 F g(-1) to 100.8, 112.4, and 147 F g(-1) after treated with tartaric, malic and oxalic acids, respectively. This finding agrees well with the spectra result of the tendency of surface conjugated degree alteration. We claim that the difference in both SH and IC among these acids is the main reason for the diverse surface characteristics as well as the improved Cs of the RGN. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Enhancement of power production with tartaric acid doped polyaniline nanowire network modified anode in microbial fuel cells.

    PubMed

    Liao, Zhi-Hong; Sun, Jian-Zhong; Sun, De-Zhen; Si, Rong-Wei; Yong, Yang-Chun

    2015-09-01

    The feasibility to use tartaric acid doped PANI for MFC anode modification was determined. Uniform PANI nanowires doped with tartaric acid were synthesized and formed mesoporous networks on the carbon cloth surface. By using this tartaric acid doped PANI modified carbon cloth (PANI-TA) as the anode, the voltage output (435 ± 15 mV) and power output (490 ± 12 mW/m(2)) of MFC were enhanced by 1.6 times and 4.1 times compared to that of MFC with plain carbon cloth anode, respectively. Strikingly, the performance of PANI-TA MFC was superior to that of the MFCs with inorganic acids doped PNAI modified anode. These results substantiated that tartaric acid is a promising PANI dopant for MFC anode modification, and provided new opportunity for MFC performance improvement. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Control of oenological products: discrimination between different botanical sources of L-tartaric acid by isotope ratio mass spectrometry.

    PubMed

    Moreno Rojas, Jose Manuel; Cosofret, Sorin; Reniero, Fabiano; Guillou, Claude; Serra, Francesca

    2007-01-01

    Following previous studies on counterfeit of wines with synthetic ingredients, the possibility of frauds by natural external L-tartaric acid has also been investigated. The aim of this research was to map the stable isotope ratios of L-tartaric acid coming from botanical species containing large amounts of this compound: grape and tamarind. Samples of L-tartaric acid were extracted from the pulp of tamarind fruits originating from several countries and from grape must. delta(13)C and delta(18)O were measured for all samples. Additional delta(2)H measurements were performed as a complementary analysis to help discrimination of the botanical origin. Different isotopic patterns were observed for the different botanical origins. The multivariate statistical analysis of the data shows clear discrimination among the different botanical and synthetic sources. This approach could be a complementary tool for the control of L-tartaric acid used in oenology. Copyright (c) 2007 John Wiley & Sons, Ltd.

  7. Rapid Photodegradation of Methyl Orange (MO) Assisted with Cu(II) and Tartaric Acid

    PubMed Central

    Guo, Jing; Chen, Xue; Shi, Ying; Lan, Yeqing; Qin, Chao

    2015-01-01

    Cu(II) and organic carboxylic acids, existing extensively in soil and aquatic environments, can form complexes that may play an important role in the photodegradation of organic contaminants. In this paper, the catalytic role of Cu(II) in the removal of methyl orange (MO) in the presence of tartaric acid with light was investigated through batch experiments. The results demonstrate that the introduction of Cu(II) could markedly enhance the photodegradation of MO. In addition, high initial concentrations of Cu(II) and tartaric acid benefited the decomposition of MO. The most rapid removal of MO assisted by Cu(II) was achieved at pH 3. The formation of Cu(II)-tartaric acid complexes was assumed to be the key factor, generating hydroxyl radicals (•OH) and other oxidizing free radicals under irradiation through a ligand-to-metal charge-transfer pathway that was responsible for the efficient degradation of MO. Some intermediates in the reaction system were also detected to support this reaction mechanism. PMID:26241043

  8. Submerged citric acid fermentation on orange peel autohydrolysate.

    PubMed

    Rivas, Beatriz; Torrado, Ana; Torre, Paolo; Converti, Attilio; Domínguez, José Manuel

    2008-04-09

    The citrus-processing industry generates in the Mediterranean area huge amounts of orange peel as a byproduct from the industrial extraction of citrus juices. To reduce its environmental impact as well as to provide an extra profit, this residue was investigated in this study as an alternative substrate for the fermentative production of citric acid. Orange peel contained 16.9% soluble sugars, 9.21% cellulose, 10.5% hemicellulose, and 42.5% pectin as the most important components. To get solutions rich in soluble and starchy sugars to be used as a carbon source for citric acid fermentation, this raw material was submitted to autohydrolysis, a process that does not make use of any acidic catalyst. Liquors obtained by this process under optimum conditions (temperature of 130 degrees C and a liquid/solid ratio of 8.0 g/g) contained 38.2 g/L free sugars (8.3 g/L sucrose, 13.7 g/L glucose, and 16.2 g/L fructose) and significant amounts of metals, particularly Mg, Ca, Zn, and K. Without additional nutrients, these liquors were employed for citric acid production by Aspergillus niger CECT 2090 (ATCC 9142, NRRL 599). Addition of calcium carbonate enhanced citric acid production because it prevented progressive acidification of the medium. Moreover, the influence of methanol addition on citric acid formation was investigated. Under the best conditions (40 mL of methanol/kg of medium), an effective conversion of sugars into citric acid was ensured (maximum citric acid concentration of 9.2 g/L, volumetric productivity of 0.128 g/(L.h), and yield of product on consumed sugars of 0.53 g/g), hence demonstrating the potential of orange peel wastes as an alternative raw material for citric acid fermentation.

  9. Sodium Picosulfate, Magnesium Oxide, and Anhydrous Citric Acid

    MedlinePlus

    Sodium picosulfate, magnesium oxide, and anhydrous citric acid combination powder is used to empty the colon (large ... clear view of the walls of the colon. Sodium picosulfate is in a class of medications called ...

  10. 21 CFR 173.280 - Solvent extraction process for citric acid.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Solvent extraction process for citric acid. 173.280... extraction process for citric acid. A solvent extraction process for recovery of citric acid from conventional Aspergillus niger fermentation liquor may be safely used to produce food-grade citric acid in...

  11. 21 CFR 173.280 - Solvent extraction process for citric acid.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Solvent extraction process for citric acid. 173... Solvent extraction process for citric acid. A solvent extraction process for recovery of citric acid from conventional Aspergillus niger fermentation liquor may be safely used to produce food-grade citric acid in...

  12. 21 CFR 173.280 - Solvent extraction process for citric acid.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Solvent extraction process for citric acid. 173... Solvent extraction process for citric acid. A solvent extraction process for recovery of citric acid from conventional Aspergillus niger fermentation liquor may be safely used to produce food-grade citric acid in...

  13. 21 CFR 173.280 - Solvent extraction process for citric acid.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Solvent extraction process for citric acid. 173... Solvent extraction process for citric acid. A solvent extraction process for recovery of citric acid from conventional Aspergillus niger fermentation liquor may be safely used to produce food-grade citric acid in...

  14. 78 FR 34338 - Citric Acid and Certain Citrate Salts From Canada: Preliminary Results of Antidumping Duty...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-07

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-122-853] Citric Acid and Certain... on citric acid and certain citrate salts (citric acid) from Canada. The period of review (POR) is May... INFORMATION: Scope of the Order The merchandise covered by this order is citric acid and certain citrate salts...

  15. Biomass pyrolysis liquid to citric acid via 2-step bioconversion.

    PubMed

    Yang, Zhiguang; Bai, Zhihui; Sun, Hongyan; Yu, Zhisheng; Li, Xingxing; Guo, Yifei; Zhang, Hongxun

    2014-12-31

    The use of fossil carbon sources for fuels and petrochemicals has serious impacts on our environment and is unable to meet the demand in the future. A promising and sustainable alternative is to substitute fossil carbon sources with microbial cell factories converting lignocellulosic biomass into desirable value added products. However, such bioprocesses require tolerance to inhibitory compounds generated during pretreatment of biomass. In this study, the process of sequential two-step bio-conversion of biomass pyrolysis liquid containing levoglucosan (LG) to citric acid without chemical detoxification has been explored, which can greatly improve the utilization efficiency of lignocellulosic biomass. The sequential two-step bio-conversion of corn stover pyrolysis liquid to citric acid has been established. The first step conversion by Phanerochaete chrysosporium (P. chrysosporium) is desirable to decrease the content of other compounds except levoglucosan as a pretreatment for the second conversion. The remaining levoglucosan in solution was further converted into citric acid by Aspergillus niger (A. niger) CBX-209. Thus the conversion of cellulose to citric acid is completed by both pyrolysis and bio-conversion technology. Under experimental conditions, levoglucosan yield is 12% based on the feedstock and the citric acid yield can reach 82.1% based on the levoglucosan content in the pyrolysis liquid (namely 82.1 g of citric acid per 100 g of levoglucosan). The study shows that P. chrysosporium and A. niger have the potential to be used as production platforms for value-added products from pyrolyzed lignocellulosic biomass. Selected P. chrysosporium is able to decrease the content of other compounds except levoglucosan and levoglucosan can be further converted into citric acid in the residual liquids by A. niger. Thus the conversion of cellulose to citric acid is completed by both pyrolysis and bio-conversion technology.

  16. 21 CFR 582.4101 - Diacetyl tartaric acid esters of mono- and diglycerides of edible fats or oils, or edible fat...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... diglycerides of edible fats or oils, or edible fat-forming fatty acids. 582.4101 Section 582.4101 Food and... Diacetyl tartaric acid esters of mono- and diglycerides of edible fats or oils, or edible fat-forming fatty acids. (a) Product. Diacetyl tartaric acid esters of mono- and diglycerides of edible fats or oils, or...

  17. 21 CFR 582.4101 - Diacetyl tartaric acid esters of mono- and diglycerides of edible fats or oils, or edible fat...

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... diglycerides of edible fats or oils, or edible fat-forming fatty acids. 582.4101 Section 582.4101 Food and... Diacetyl tartaric acid esters of mono- and diglycerides of edible fats or oils, or edible fat-forming fatty acids. (a) Product. Diacetyl tartaric acid esters of mono- and diglycerides of edible fats or oils, or...

  18. 21 CFR 582.4101 - Diacetyl tartaric acid esters of mono- and diglycerides of edible fats or oils, or edible fat...

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... diglycerides of edible fats or oils, or edible fat-forming fatty acids. 582.4101 Section 582.4101 Food and... Diacetyl tartaric acid esters of mono- and diglycerides of edible fats or oils, or edible fat-forming fatty acids. (a) Product. Diacetyl tartaric acid esters of mono- and diglycerides of edible fats or oils, or...

  19. Thoron-meso-tartaric acid system for determination of thorium

    USGS Publications Warehouse

    Fletcher, M.H.; Grimaldi, F.S.; Jenkins, L.B.

    1957-01-01

    In the spectrophotometric determination of thorium with thoron, mesotartaric acid is used as a masking reagent for zirconium. The effects of different experimental variables such as the concentrations of the reagents, time, and temperature, and the behavior of 35 ions which might be present in thorium ores are discussed. A dilution procedure is given for the direct determination of thorium in zircon (ZrSiO4) that is also generally applicable to other materials.

  20. 76 FR 47146 - Citric Acid and Certain Citrate Salts From the People's Republic of China: Extension of Time...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-04

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-570-937] Citric Acid and Certain... review of the antidumping duty order on citric acid and certain citrate salts (``citric acid'') from the... of citric acid from the PRC. See Citric Acid and Certain Citrate Salts From the People's Republic of...

  1. Structural, vibrational and thermal studies of a new nonlinear optical material: L-asparagine-L-tartaric acid.

    PubMed

    Moovendaran, K; Srinivasan, Bikshandarkoil R; Kalyana Sundar, J; Martin Britto Dhas, S A; Natarajan, S

    2012-06-15

    Crystals of a new nonlinear optical (NLO) material, viz., L-asparagine-L-tartaric acid (LALT) (1) were grown by slow evaporation of an aqueous solution containing equimolar concentrations of L-asparagine and L-tartaric acid. The structure of the title compound which crystallizes in the non-centrosymmetric monoclinic space group P2(1) consists of a molecule of L-asparagine and a molecule of free l-tartaric acid both of which are interlinked by three varieties of H-bonding interactions namely O-H···O, N-H···O and C-H···O. The UV-Vis-NIR spectrum of 1 reveals its transparent nature while the vibrational spectra confirm the presence of the functional groups in 1. The thermal stability and second harmonic generation (SHG) conversion efficiency of 1 were investigated. Copyright © 2012 Elsevier B.V. All rights reserved.

  2. Catalytic role of Cu(II) in the reduction of Cr(VI) by citric acid under an irradiation of simulated solar light.

    PubMed

    Li, Ying; Chen, Cheng; Zhang, Jing; Lan, Yeqing

    2015-05-01

    The catalytic role of Cu(II) in the reduction of Cr(VI) by citric acid with simulated solar light was investigated. The results demonstrated that Cu(II) could significantly accelerate Cr(VI) reduction and the reaction obeyed to pseudo zero-order kinetics with respect to Cr(VI). The removal of Cr(VI) was related to the initial concentrations of Cu(II), citric acid, and the types of organic acids. The optimal removal of Cr(VI) was achieved at pH 4, and the rates of Cu(II) photocatalytic reduction of Cr(VI) by organic acids were in the order: tartaric acid (two α-OH groups, two -COOH groups)>citric acid (one α-OH group, three -COOH groups)>malic acid (one α-OH group, two -COOH groups)>lactic acid (one α-OH group, one -COOH group)≫succinic acid (two -COOH groups), suggesting that the number of α-OH was the key factor for the reaction, followed by the number of -COOH. The formation of Cu(II)-citric acid complex could generate Cu(I) and radicals through a pathway of metal-ligand-electron transfer, promoting the reduction of Cr(VI). This study is helpful to fully understanding the conversion of Cr(VI) in the existence of both organic acids and Cu(II) with solar light in aquatic environments. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Citric acid metabolism in hetero- and homofermentative lactic acid bacteria.

    PubMed Central

    Drinan, D F; Robin, S; Cogan, T M

    1976-01-01

    The effect of citrate on production of diacetyl and acetoin by four strains each of heterofermentative and homofermentative lactic acid bacteria capable of utilizing citrate was studied. Acetoin was quantitatively the more important compound. The heterofermentative bacteria produced no acetoin or diacetyl in the absence of citrate, and two strains produced traces of acetoin in its presence. Citrate stimulated the growth rate of the heterofermentative lactobacilli. Acidification of all heterofermentative cultures with citric acid resulted in acetoin production. Destruction of accumulated acetoin appeared to coincide with the disappearance of citrate. All homofermentative bacteria produced more acetoin and diacetyl in the presence of citrate than in its absence. Citrate utilization was begun immediately by the streptococci but was delayed until at least the middle of the exponential phase in the case of the lactobacilli. PMID:5054

  4. 7 CFR 51.1178 - Maximum anhydrous citric acid permissible for corresponding total soluble solids.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 2 2013-01-01 2013-01-01 false Maximum anhydrous citric acid permissible for... Common Sweet Oranges (citrus Sinensis (l) Osbeck) § 51.1178 Maximum anhydrous citric acid permissible for... following Table II together with the minimum ratio of total soluble solids to anhydrous citric acid: Table...

  5. 7 CFR 51.1178 - Maximum anhydrous citric acid permissible for corresponding total soluble solids.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false Maximum anhydrous citric acid permissible for... Common Sweet Oranges (citrus Sinensis (l) Osbeck) § 51.1178 Maximum anhydrous citric acid permissible for... following Table II together with the minimum ratio of total soluble solids to anhydrous citric acid: Table...

  6. 7 CFR 51.1178 - Maximum anhydrous citric acid permissible for corresponding total soluble solids.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 2 2012-01-01 2012-01-01 false Maximum anhydrous citric acid permissible for... Sinensis (l) Osbeck) § 51.1178 Maximum anhydrous citric acid permissible for corresponding total soluble solids. For determining the grade of juice, the maximum permissible anhydrous citric acid content in...

  7. 21 CFR 173.280 - Solvent extraction process for citric acid.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Solvent extraction process for citric acid. 173..., Lubricants, Release Agents and Related Substances § 173.280 Solvent extraction process for citric acid. A solvent extraction process for recovery of citric acid from conventional Aspergillus niger fermentation...

  8. 7 CFR 51.1178 - Maximum anhydrous citric acid permissible for corresponding total soluble solids.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Maximum anhydrous citric acid permissible for... Sinensis (l) Osbeck) § 51.1178 Maximum anhydrous citric acid permissible for corresponding total soluble solids. For determining the grade of juice, the maximum permissible anhydrous citric acid content in...

  9. 78 FR 64914 - Citric Acid and Certain Citrate Salts From Canada: Final Results of Antidumping Duty...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-30

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-122-853] Citric Acid and Certain... results of the third administrative review of the antidumping duty order on citric acid and certain...\\ See Citric Acid and Certain Citrate Salts from Canada: Preliminary Results of Antidumping Duty...

  10. Citric acid-assisted phytoextraction of lead: a field experiment.

    PubMed

    Freitas, Eriberto Vagner; Nascimento, Clístenes Williams; Souza, Adailson; Silva, Fernando Bruno

    2013-06-01

    Soil contamination with heavy metals has become a serious environmental problem that requires affordable strategies of remediation. This study was carried out to assess the performance of maize and vetiver in the phytoextraction of Pb from a soil contaminated by battery recycling activities. The species were planted with different spacings between rows (0.80, 0.65 and 0.50m). Citric acid (40mmolkg(-1)) was applied on each experimental plot on the 61st d of cultivation in order to solubilize the Pb and assist the phytoextraction. The results showed that the chelating agent promoted a 14-fold increase in the Pb concentration in maize shoots as compared to the control, which accumulated only 111mgkg(-1) of the metal. The citric acid induced a Pb concentration in vetiver shoots that was 7.2-6.7-fold higher than the control at both the 0.65 and 0.50m plant spacing, respectively. The use of citric acid increased substantially the uptake and translocation of Pb to the shoots, regardless of plant spacing. Citric acid was efficient in solubilizing Pb from the soil and inducing its uptake by both species. Environmentally-friendly and cost effective, commercial citric acid is recommended for assisting Pb-phytoextraction in the studied area. Due to the low natural solubility of Pb and a time frame needed of longer than 150yr to accomplish the clean-up, phytoextraction with no chelate assistance is not recommended for the area. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. The effects of egg and diacetyl tartaric acid esters of monoglycerides addition on gluten-free sorghum bread quality

    USDA-ARS?s Scientific Manuscript database

    The impact of whole egg addition (as is) at 20, 25, or 30% (flour basis) on sorghum bread quality was evaluated. The use of the antistaling agent diacetyl tartaric acid esters of monoglycerides (DATEM) at 0.5% (flour basis) at each of the egg addition levels was also studied. Evaluated quality facto...

  12. Cleaner production of citric acid by recycling its extraction wastewater treated with anaerobic digestion and electrodialysis in an integrated citric acid-methane production process.

    PubMed

    Xu, Jian; Su, Xian-Feng; Bao, Jia-Wei; Chen, Yang-Qiu; Zhang, Hong-Jian; Tang, Lei; Wang, Ke; Zhang, Jian-Hua; Chen, Xu-Sheng; Mao, Zhong-Gui

    2015-01-01

    To solve the pollution problem of extraction wastewater in citric acid production, an integrated citric acid-methane production process was proposed. Extraction wastewater was treated through anaerobic digestion and the anaerobic digestion effluent (ADE) was recycled for the next batch of citric acid fermentation, thus eliminating wastewater discharge and reducing water consumption. Excessive Na(+) contained in ADE could significantly inhibit citric acid fermentation in recycling and was removed by electrodialysis in this paper. Electrodialysis performance was improved after pretreatment of ADE with air stripping and activated carbon adsorption to remove precipitable metal ions and pigments. Moreover, the concentrate water was recycled and mixed with feed to improve the water recovery rate above 95% in electrodialysis treatment, while the dilute water was collected for citric acid fermentation. The removal rate of Na(+) in ADE was above 95% and the citric acid production was even higher than that with tap water. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. A stimuli-responsive fluorescence platform for simultaneous determination of D-isoascorbic acid and Tartaric acid based on Maillard reaction product

    NASA Astrophysics Data System (ADS)

    Zhao, Yanmei; Yuan, Haiyan; Zhang, Xinling; Yang, Jidong

    2018-05-01

    An activatable fluorescence monitoring platform based on a novel Maillard reaction product from D-glucose and L-arginine was prepared through a facile one-pot approach and applied for simultaneous detection of D-isoascorbic acid and tartaric acid. In this work, the new Maillard reaction product GLA was first obtained, and its fluorescence intensity can be effectively quenched by KMnO4, resulting from a new complex (GLA-KMnO4) formation between GLA and KMnO4. Upon addition of D-isoascorbic acid or tartaric acid, an enhanced fluorescence was observed under the optimumed experimental conditions, indicating a stimuli-responsive fluorescence turn on platform for D-isoascorbic acid or tartaric acid can be developed. The corresponding experimental results showed that this turn on fluorescence sensing platform has a high sensitivity for D-isoascorbic acid or tartaric acid, because the detection limits were 5.9 μM and 21.5 μM, respectively. Additionally, this proposed sensing platform was applied to simultaneously detection of D-isoascorbic acid and tartaric acid in real tap water samples with satisfactory results.

  14. A stimuli-responsive fluorescence platform for simultaneous determination of d-isoascorbic acid and Tartaric acid based on Maillard reaction product.

    PubMed

    Zhao, Yanmei; Yuan, Haiyan; Zhang, Xinling; Yang, Jidong

    2018-05-05

    An activatable fluorescence monitoring platform based on a novel Maillard reaction product from d-glucose and L-arginine was prepared through a facile one-pot approach and applied for simultaneous detection of d-isoascorbic acid and tartaric acid. In this work, the new Maillard reaction product GLA was first obtained, and its fluorescence intensity can be effectively quenched by KMnO 4 , resulting from a new complex (GLA-KMnO 4 ) formation between GLA and KMnO 4 . Upon addition of d-isoascorbic acid or tartaric acid, an enhanced fluorescence was observed under the optimumed experimental conditions, indicating a stimuli-responsive fluorescence turn on platform for d-isoascorbic acid or tartaric acid can be developed. The corresponding experimental results showed that this turn on fluorescence sensing platform has a high sensitivity for d-isoascorbic acid or tartaric acid, because the detection limits were 5.9μM and 21.5μM, respectively. Additionally, this proposed sensing platform was applied to simultaneously detection of d-isoascorbic acid and tartaric acid in real tap water samples with satisfactory results. Copyright © 2018 Elsevier B.V. All rights reserved.

  15. Preparation of long alumina fibers by sol-gel method using tartaric acid

    NASA Astrophysics Data System (ADS)

    Tan, Hong-Bin

    2011-12-01

    Long alumina fibers were prepared by sol-gel method. The spinning sol was obtained by mixing aluminum nitrate, tartaric acid, and polyvinylpyrrolidone with a mass ratio of 10:3:1.5. Thermogravimetry-differential scanning calorimetry (TG-DSC), Fourier transform infrared (FT-IR) spectra, X-ray diffraction (XRD), and scanning electron microscopy (SEM) were used to characterize the properties of the gel and ceramic fibers. A little of α-Al2O3 phase is observed in the alumina precursor gel fibers sintered at 1273 K. The fibers with a uniform diameter can be obtained when sintered at 1473 K, and its main phase is also indentified as α-Al2O3.

  16. Effect of the association between citric acid and EDTA on root surface etching.

    PubMed

    Manzolli Leite, Fabio Renato; Nascimento, Gustavo Giacomelli; Manzolli Leite, Elza Regina; Leite, Amauri Antiquera; Cezar Sampaio, Josá Eduardo

    2013-09-01

    This study aims to compare the clot stabilization on root surfaces conditioned with citric acid and ethylenediamine-tetraacetic acid (EDTA). Scaled root samples (n = 100) were set in fve groups: group I-control group (saline solution); group II (24% EDTA); group III (25% citric acid); group IV (EDTA + citric acid); group V (citric acid + EDTA). Fifty samples were assessed using the root surface modifcation index (RSMI). The other 50 received a blood drop after conditioning. Clot formation was assessed using blood elements adhesion index (BEAI). A blind examiner evaluated photomicrographs. Statistical analysis considered p < 0.05. Groups-III and G-V attained the best results for RSMI and BEAI in comparison to control. The worst results for clot stabilization were seen in group-II. EDTA employment before citric acid (group-IV) reduced clot formation in comparison to citric acid use alone (group-III). Root conditioning with citric acid alone and before EDTA had the best results for smear layer removal and clot stabilization. EDTA inhibited clot stabilization on root surface and must have a residual activity once it has diminished clot adhesion to root even after citric acid conditioning. Thus, EDTA can be used to neutralize citric acid effects on periodontal cells without affecting clot stabilization. Clinical signifcance: To demonstrate that citric acid use on root surfaces previously affected by periodontal disease may favor clot stabilization and may have a benefcial effect on surgical outcomes. Also, EDTA can be used to neutralize citric acid effects on periodontal cells.

  17. 21. Interior view of citric acid air pollution control room ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    21. Interior view of citric acid air pollution control room (also known as scrubber room) in Components Test Laboratory (T-27), looking southeast. Photograph shows upgraded instrumentation, piping, tanks, and technological modifications installed in 1997-99 to accommodate component testing requirements for the Atlas V missile. - Air Force Plant PJKS, Systems Integration Laboratory, Components Test Laboratory, Waterton Canyon Road & Colorado Highway 121, Lakewood, Jefferson County, CO

  18. 77 FR 1455 - Citric Acid and Certain Citrate Salts From the People's Republic of China: Extension of Time...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-10

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-570-937] Citric Acid and Certain... review of the antidumping duty order on citric acid and certain citrate salts (``citric acid'') from the... practicable to complete the preliminary results of the administrative review of citric acid from the PRC...

  19. 77 FR 22560 - Citric Acid and Certain Citrate Salts From the People's Republic of China: Extension of Time...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-16

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-570-937] Citric Acid and Certain... review of the antidumping duty order on citric acid and certain citrate salts (``citric acid'') from the... Request for Revocation in Part, 76 FR 37781, 37785 (June 28, 2011). \\2\\ See Citric Acid and Certain...

  20. 76 FR 49735 - Citric Acid and Certain Citrate Salts From the People's Republic of China: Partial Rescission of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-11

    ... DEPARTMENT OF COMMERCE International Trade Administration [C-570-938] Citric Acid and Certain... citric acid and certain citrate salts (``citric acid'') from the People's Republic of China (``PRC...., Ltd. (``Xinghua''), a producer and exporter of citric acid, timely requested that the Department...

  1. Citric acid application for denitrification process support in biofilm reactor.

    PubMed

    Mielcarek, Artur; Rodziewicz, Joanna; Janczukowicz, Wojciech; Dabrowska, Dorota; Ciesielski, Slawomir; Thornton, Arthur; Struk-Sokołowska, Joanna

    2017-03-01

    The study demonstrated that citric acid, as an organic carbon source, can improve denitrification in Anaerobic Sequencing Batch Biofilm Reactor (AnSBBR). The consumption rate of the organic substrate and the denitrification rate were lower during the period of the reactor's acclimatization (cycles 1-60; 71.5 mgCOD L -1  h -1 and 17.81 mgN L -1  h -1 , respectively) than under the steady state conditions (cycles 61-180; 143.8 mgCOD L -1  h -1 and 24.38 mgN L -1  h -1 ). The biomass yield coefficient reached 0.04 ± 0.02 mgTSS· mgCOD re -1 (0.22 ± 0.09 mgTSS mgN re -1 ). Observations revealed the diversified microbiological ecology of the denitrifying bacteria. Citric acid was used mainly by bacteria representing the Trichoccocus genus, which represented above 40% of the sample during the first phase of the process (cycles 1-60). In the second phase (cycles 61-180) the microorganisms the genera that consumed the acetate and formate, as the result of citric acid decomposition were Propionibacterium (5.74%), Agrobacterium (5.23%), Flavobacterium (1.32%), Sphaerotilus (1.35%), Erysipelothrix (1.08%). Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Citric-Acid-Derived Photo-cross-Linked Biodegradable Elastomers

    PubMed Central

    Gyawali, Dipendra; Tran, Richard T.; Guleserian, Kristine J.; Tang, Liping; Yang, Jian

    2010-01-01

    Citric-acid-derived thermally cross-linked biodegradable elastomers (CABEs) have recently received significant attention in various biomedical applications, including tissue-engineering orthopedic devices, bioimaging and implant coatings. However, citric-acid-derived photo-cross-linked biodegradable elastomers are rarely reported. Herein, we report a novel photo-cross-linked biodegradable elastomer, referred to as poly(octamethylene maleate citrate) (POMC), which preserves pendant hydroxyl and carboxylic functionalities after cross-linking for the potential conjugation of biologically active molecules. POMC is a low-molecular-mass pre-polymer with a molecular mass average between 701 and 1291 Da. POMC networks are soft and elastic with an initial modulus of 0.07 to 1.3 MPa and an elongation at break between 38 and 382%. FT-IR–ATR results confirmed the successful surface immobilization of type-I collagen onto POMC films, which enhanced in vitro cellular attachment and proliferation. Photo-polymerized POMC films implanted subcutaneously into Sprague–Dawley rats demonstrated minimal in vivo inflammatory responses. The development of POMC enriches the family of citric-acid-derived biodegradable elastomers and expands the available biodegradable polymers for versatile needs in biomedical applications. PMID:20557687

  3. Citric acid production from extract of Jerusalem artichoke tubers by the genetically engineered yeast Yarrowia lipolytica strain 30 and purification of citric acid.

    PubMed

    Wang, Ling-Fei; Wang, Zhi-Peng; Liu, Xiao-Yan; Chi, Zhen-Ming

    2013-11-01

    In this study, citric acid production from extract of Jerusalem artichoke tubers by the genetically engineered yeast Yarrowia lipolytica strain 30 was investigated. After the compositions of the extract of Jerusalem artichoke tubers for citric acid production were optimized, the results showed that natural components of extract of Jerusalem artichoke tubers without addition of any other components were suitable for citric acid production by the yeast strain. During 10 L fermentation using the extract containing 84.3 g L(-1) total sugars, 68.3 g L(-1) citric acid was produced and the yield of citric acid was 0.91 g g(-1) within 336 h. At the end of the fermentation, 9.2 g L(-1) of residual total sugar and 2.1 g L(-1) of reducing sugar were left in the fermented medium. At the same time, citric acid in the supernatant of the culture was purified. It was found that 67.2 % of the citric acid in the supernatant of the culture was recovered and purity of citric acid in the crystal was 96 %.

  4. Coamorphous Loratadine-Citric Acid System with Enhanced Physical Stability and Bioavailability.

    PubMed

    Wang, Jin; Chang, Ruimiao; Zhao, Yanan; Zhang, Jiye; Zhang, Ting; Fu, Qiang; Chang, Chun; Zeng, Aiguo

    2017-10-01

    Coamorphous systems using citric acid as a small molecular excipient were studied for improving physical stability and bioavailability of loratadine, a BCS class II drug with low water solubility and high permeability. Coamorphous loratadine-citric acid systems were prepared by solvent evaporation technique and characterized by differential scanning calorimetry, X-ray powder diffraction, and Fourier transform infrared spectroscopy. Solid-state analysis proofed that coamorphous loratadine-citric acid system (1:1) was amorphous and homogeneous, had a higher T g over amorphous loratadine, and the intermolecular hydrogen bond interactions between loratadine and citric acid exist. The solubility and dissolution of coamorphous loratadine-citric acid system (1:1) were found to be significantly greater than those of crystalline and amorphous form. The pharmacokinetic study in rats proved that coamorphous loratadine-citric acid system (1:1) could significantly improve absorption and bioavailability of loratadine. Coamorphous loratadine-citric acid system (1:1) showed excellently physical stability over a period of 3 months at 25°C under 0% RH and 25°C under 60% RH conditions. The improved stability of coamorphous loratadine-citric acid system (1:1) could be related to an elevated T g over amorphous form and the intermolecular hydrogen bond interactions between loratadine and citric acid. These studies demonstrate that the developed coamorphous loratadine-citric acid system might be a promising oral formulation for improving solubility and bioavailability of loratadine.

  5. Electrochemical characterization and electrode kinetics for antimony electrodeposition from its oxychloride solution in the presence of tartaric acid

    NASA Astrophysics Data System (ADS)

    Majidzade, Vusala Asim; Guliyev, Parvin Heydar; Aliyev, Akif Shikhan; Elrouby, Mahmoud; Tagiyev, Dilgam Babir

    2017-05-01

    This work is devoted to investigate the process of the electrochemical deposition of antimony from antimony oxychloride solution in the presence of tartaric acid in aqueous media. The kinetics and the mechanism of the electrodeposition process at the electrode surface are studied and proposed by the aid of cyclic, linear sweep voltammetric and chronoamperometric characterization methods. It is found that, the process is affected by the presence of tartaric acid and some factors during the electro-reduction process. The results also show that, the temperature, the potential sweep rate and the concentration of antimony have a great influence on the achievement of the electrodeposition process. Some important parameters are calculated such as, the activation energy of the electrochemical reaction, the diffusion coefficient and the number of saturated nucleation sites. The electrodeposited film is examined using X-ray diffraction, scanning electron microscopy and Energy Dispersive Spectroscopy.

  6. The structure, vibrational spectra and nonlinear optical properties of the L-lysine × tartaric acid complex—Theoretical studies

    NASA Astrophysics Data System (ADS)

    Drozd, M.; Marchewka, M. K.

    2006-05-01

    The room temperature X-ray studies of L-lysine × tartaric acid complex are not unambiguous. The disorder of three atoms of carbon in L-lysine molecule is observed. These X-ray studies are ambiguous. The theoretical geometry study performed by DFT methods explain the most doubts which are connected with crystallographic measurements. The theoretical vibrational frequencies and potential energy distribution (PED) of L-lysine × tartaric acid were calculated by B3LYP method. The calculated frequencies were compared with experimental measured IR spectra. The complete assignment of the bands has been made on the basis of the calculated PED. The restricted Hartee-Fock (RHF) methods were used for calculation of the hyperpolarizability for investigated compound. The theoretical results are compared with experimental value of β.

  7. Fermentative production of high titer citric acid from corn stover feedstock after dry dilute acid pretreatment and biodetoxification.

    PubMed

    Zhou, Ping-Ping; Meng, Jiao; Bao, Jie

    2017-01-01

    The aim of this work is to study the citric acid fermentation by a robust strain Aspergillus niger SIIM M288 using corn stover feedstock after dry dilute sulfuric acid pretreatment and biodetoxification. Citric acid at 100.04g/L with the yield of 94.11% was obtained, which are comparable to the starch or sucrose based citric acid fermentation. No free wastewater was generated in the overall process from the pretreatment to citric acid fermentation. Abundant divalent metal ions as well as high titer of potassium, phosphate, and nitrogen were found in corn stover hydrolysate. Further addition of extra nutrients showed no impact on increasing citric acid formation except minimum nitrogen source was required. Various fermentation parameters were tested and only minimum regulation was required during the fermentation. This study provided a biorefining process for citric acid fermentation from lignocellulose feedstock with the maximum citric acid titer and yield. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Production of citric acid using its extraction wastewater treated by anaerobic digestion and ion exchange in an integrated citric acid-methane fermentation process.

    PubMed

    Xu, Jian; Chen, Yang-Qiu; Zhang, Hong-Jian; Tang, Lei; Wang, Ke; Zhang, Jian-Hua; Chen, Xu-Sheng; Mao, Zhong-Gui

    2014-08-01

    In order to solve the problem of extraction wastewater pollution in citric acid industry, an integrated citric acid-methane fermentation process is proposed in this study. Extraction wastewater was treated by mesophilic anaerobic digestion and then used to make mash for the next batch of citric acid fermentation. The recycling process was done for seven batches. Citric acid production (82.4 g/L on average) decreased by 34.1 % in the recycling batches (2nd-7th) compared with the first batch. And the residual reducing sugar exceeded 40 g/L on average in the recycling batches. Pigment substances, acetic acid, ammonium, and metal ions in anaerobic digestion effluent (ADE) were considered to be the inhibitors, and their effects on the fermentation were studied. Results indicated that ammonium, Na(+) and K(+) in the ADE significantly inhibited citric acid fermentation. Therefore, the ADE was treated by acidic cation exchange resin prior to reuse to make mash for citric acid fermentation. The recycling process was performed for ten batches, and citric acid productions in the recycling batches were 126.6 g/L on average, increasing by 1.7 % compared with the first batch. This process could eliminate extraction wastewater discharge and reduce water resource consumption.

  9. Citric acid inhibits development of cataracts, proteinuria and ketosis in streptozotocin (type1) diabetic rats

    PubMed Central

    Nagai, Ryoji; Nagai, Mime; Shimasaki, Satoko; Baynes, John W.; Fujiwara, Yukio

    2010-01-01

    Although many fruits such as lemon and orange contain citric acid, little is known about beneficial effects of citric acid on health. Here we measured the effect of citric acid on the pathogenesis of diabetic complications in streptozotocin-induced diabetic rats. Although oral administration of citric acid to diabetic rats did not affect blood glucose concentration, it delayed the development of cataracts, inhibited accumulation of advanced glycation end products (AGEs) such as Nε-(carboxyethyl)lysine (CEL) and Nε-(carboxymethyl)lysine (CML) in lens proteins, and protected against albuminuria and ketosis . We also show that incubation of protein with acetol, a metabolite formed from acetone by acetone monooxygenase, generate CEL, suggesting that inhibition of ketosis by citric acid may lead to the decrease in CEL in lens proteins. These results demonstrate that the oral administration of citric acid ameliorates ketosis and protects against the development of diabetic complications in an animal model of type 1 diabetes. PMID:20117096

  10. Structural, optical, thermal and mechanical properties of Urea tartaric acid single crystals.

    PubMed

    Vinothkumar, P; Rajeswari, K; Kumar, R Mohan; Bhaskaran, A

    2015-06-15

    Urea tartaric acid (UT) an organic nonlinear optical (NLO) material was synthesized from aqueous solution and the crystals were grown by the slow evaporation technique. The single crystal X-ray diffraction (XRD) analysis revealed that the UT crystal belongs to the orthorhombic system. The functional groups of UT have been identified by the Fourier transform infrared spectral studies. The optical transparent window in the visible and near the IR regions was investigated. The transmittance of UT has been used to calculate the refractive index (n) as a function of the wavelength. The nonlinear optical property of the grown crystal has been confirmed by the Kurtz powder second harmonic generation test. The birefringence of the crystal was determined using a tungsten halogen lamp source. The laser induced surface damage threshold for the grown crystal was measured using the Nd:YAG laser. The anisotropic in mechanical property of the grown crystals was studied using Vicker's microhardness tester at different planes. The etch pit density of UT crystals was investigated. The thermal behavior of UT was investigated using the TG-DTA and DSC studies. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Leaching with Penicillium simplicissimum: Influence of metals and buffers on proton extrusion and citric acid production

    SciTech Connect

    Franz, A.; Burgstaller, W.; Schinner, F.

    1991-03-01

    In the presence of insoluble metal oxides (industrial filter dust, zinc oxide, synthetic mixture of metal oxides), Penicillium simplicissimum developed the ability to excrete considerable amounts of citric acid (>100 mM). Parallel with the increase of citric acid concentration in the culture broth, zinc was solubilized from zinc oxide. The adsorption of filter dust onto the mycelium (the pellets formed were less than 1 mm in diameter) was required for not only the citric acid excretion but also the leaching of zinc. When the filter dust was replaced with a synthetic mixture of metal oxides or with zinc oxide inmore » combination with trace elements, levels of adsorption and citric acid production were observed to be similar to those in experiments where industrial filter dust was used. The two most important properties of the filter dust were its heavy-metal content and its buffering capacity. These properties were simulated by adding heavy metals in soluble form (as chlorides, sulfates, or nitrates) or soluble buffers to the medium. Both heavy metals and buffers were not able to induce a citric acid efflux. As with citric acid production by Aspergillus niger, the addition of manganese lowered citric acid excretion (by 40% with metal oxide-induced citric acid efflux and by 100% with urea-induced citric acid efflux). Copper antagonized the effect of manganese. The mechanism for the bulk of citric acid excretion by P. simplicissimum, however, seemed to be different from that described for citric acid accumulation by A. niger. Because of the inefficiency of metals in solubilized form and of soluble buffers to induce a strong citric acid efflux, adsorption of an insoluble metal compound (zinc oxide) turned out to be essential.« less

  12. Scanning Electron Microscopic Evaluation of Root Canal Irrigation with Saline, Sodium Hypochlorite, and Citric Acid,

    DTIC Science & Technology

    1983-12-01

    with six different irrigation regimens. Sodium hypochlorite (NaOCl) was significantly more effective than citric acid in "* removing superficial...EVALUATION OF ROOT CANAL IRRIGATION WITH SALINE, SODIUM HYPOCHLORITE , AND CITRIC ACID 4 *J. Craig Baumgartner, D.D.S., M.S. • **Carolyn M. Brown, D.D.S., M.S...preparation with six different irrigation regimens. Sodium hypochlorite (NaOCl) was significantly more effective than citric acid in removing superficial

  13. Electrodeposited Fe-Co films prepared from a citric-acid-based plating bath

    NASA Astrophysics Data System (ADS)

    Yanai, T.; Uto, H.; Shimokawa, T.; Nakano, M.; Fukunaga, H.; Suzuki, K.

    2013-06-01

    Electrodeposited Fe-Co films are commonly prepared in a boric-acid-based bath. In this research, we applied citric acid instead of boric acid for the plating of Fe-Co films because boron in the waste bath is restricted by environmental-protection regulations in Japan. We evaluated the effect of citric acid on the magnetic and structural properties of the films. The saturation magnetization of the Fe-Co films slightly increased while the Fe content in the Fe-Co films decreased with increasing citric acid concentration. The lowest coercivity value of 240 A/m was obtained at a citric acid concentration of 100 g/L. The plating bath with this citric acid concentration enabled us to obtain Fe-Co films with high saturation magnetizations and smooth surface morphologies.

  14. Simple citric acid-catalyzed surface esterification of cellulose nanocrystals.

    PubMed

    Ávila Ramírez, Jhon Alejandro; Fortunati, Elena; Kenny, José María; Torre, Luigi; Foresti, María Laura

    2017-02-10

    A simple straightforward route for the surface esterification of cellulose nanocrystals (CNC) is herein proposed. CNC obtained from microcrystalline cellulose were acetylated using as catalyst citric acid, a α-hydroxy acid present in citrus fruits and industrially produced by certain molds in sucrose or glucose-containing medium. No additional solvent was added to the system; instead, the acylant (acetic anhydride) was used in sufficient excess to allow CNC dispersion and proper suspension agitation. By tuning the catalyst load, CNC with two different degree of substitution (i.e. DS=0.18 and 0.34) were obtained. Acetylated cellulose nanocrystals were characterized in terms of chemical structure, crystallinity, morphology, thermal decomposition and dispersion in a non-polar solvent. Results illustrated for the first time the suitability of the protocol proposed for the simple surface acetylation of cellulose nanocrystals. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Ascorbate metabolism and the developmental demand for tartaric and oxalic acids in ripening grape berries

    PubMed Central

    2009-01-01

    Background Fresh fruits are well accepted as a good source of the dietary antioxidant ascorbic acid (Asc, Vitamin C). However, fruits such as grapes do not accumulate exceptionally high quantities of Asc. Grapes, unlike most other cultivated fruits do however use Asc as a precursor for the synthesis of both oxalic (OA) and tartaric acids (TA). TA is a commercially important product in the wine industry and due to its acidifying effect on crushed juice it can influence the organoleptic properties of the wine. Despite the interest in Asc accumulation in fruits, little is known about the mechanisms whereby Asc concentration is regulated. The purpose of this study was to gain insights into Asc metabolism in wine grapes (Vitis vinifera c.v. Shiraz.) and thus ascertain whether the developmental demand for TA and OA synthesis influences Asc accumulation in the berry. Results We provide evidence for developmentally differentiated up-regulation of Asc biosynthetic pathways and subsequent fluctuations in Asc, TA and OA accumulation. Rapid accumulation of Asc and a low Asc to dehydroascorbate (DHA) ratio in young berries was co-ordinated with up-regulation of three of the primary Asc biosynthetic (Smirnoff-Wheeler) pathway genes. Immature berries synthesised Asc in-situ from the primary pathway precursors D-mannose and L-galactose. Immature berries also accumulated TA in early berry development in co-ordination with up-regulation of a TA biosynthetic gene. In contrast, ripe berries have up-regulated expression of the alternative Asc biosynthetic pathway gene D-galacturonic acid reductase with only residual expression of Smirnoff-Wheeler Asc biosynthetic pathway genes and of the TA biosynthetic gene. The ripening phase was further associated with up-regulation of Asc recycling genes, a secondary phase of increased accumulation of Asc and an increase in the Asc to DHA ratio. Conclusion We demonstrate strong developmental regulation of Asc biosynthetic, recycling and catabolic

  16. Cytotoxicity analysis of EDTA and citric acid applied on murine resident macrophages culture.

    PubMed

    Amaral, K F; Rogero, M M; Fock, R A; Borelli, P; Gavini, G

    2007-05-01

    To assess the ex vivo cytotoxicity of EDTA and citric acid solutions on macrophages. The cytotoxicity of 17% EDTA and 15% citric acid was evaluated on murine macrophage cultures using MTT-Tetrazolium method [3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyl tetrazolium bromide]. A total of 5 x 10(5) cells were plated in medium culture with 17% EDTA or 15% citric acid. Fresh medium was used as a control. Toxicity values were analysed statistically by anova and Tukey's test (P<0.05) at short (0, 6, 12, 24 h) and medium periods (1, 3, 5, 7 days), using ELISA absorbance. On the short term, both EDTA (0.253 nm) and citric acid (0.260 nm) exhibited cytotoxic effects on macrophage cultures (P<0.05). On the medium term, statistical differences were observed (P<0.05) between the groups. EDTA (0.158 nm) and citric acid (0.219 nm) were cytotoxic when compared with the control group; EDTA-reduced macrophage viability significantly more than citric acid (P<0.05). Both EDTA and citric acid had effects on macrophages cells ex vivo, but citric acid was less toxic in periods from 1 to 7 days of use.

  17. Effect of citric acid modification of aspen wood on sorption of copper ion

    Treesearch

    James D. McSweeny; Roger M. Rowell; Soo Hong Min

    2006-01-01

    Milled aspen wood was thermochemically modified with citric acid for the purpose of improving the copper (Cu2+) ion sorption capacity of the wood when tested in 24-hour equilibrium batch tests. The wood-citric acid adducts provided additional carboxyl groups to those in the native wood and substantially increased Cu2+ ion uptake of the modified wood compared with that...

  18. Effects of the food additive, citric acid, on kidney cells of mice.

    PubMed

    Chen, Xg; Lv, Qx; Liu, Ym; Deng, W

    2015-01-01

    Citric acid is a food additive that is widely used in the food and drink industry. We investigated the effects of citric acid injection on mouse kidney. Forty healthy mice were divided into four groups of 10 including one control group and three citric acid-treated groups. Low dose, middle dose and high dose groups were given doses of 120, 240 and 480 mg/kg of citric acid, respectively. On day 7, kidney tissues were collected for histological, biochemical and molecular biological examination. We observed shrinkage of glomeruli, widened urinary spaces and capillary congestion, narrowing of the tubule lumen, edema and cytoplasmic vacuolated tubule cells, and appearance of pyknotic nuclei. The relation between histopathological changes and citric acid was dose dependent. Compared to the control, T-SOD and GSH-Px activities in the treated groups decreased with increasing doses of citric acid, NOS activity tended to increase, and H2O2 and MDA contents gradually decreased, but the differences between any treated group and the control were not statistically significant. The apoptosis assay showed a dose-dependent increase of caspase-3 activity after administering citrate that was statistically significant. DNA ladder formation occurred after treatment with any dose of citric acid. We concluded that administration of citric acid may cause renal toxicity in mice.

  19. Effects of sodium citrate, citric acid and lactic acid on human blood coagulation.

    PubMed

    Scaravilli, Vittorio; Di Girolamo, Luca; Scotti, Eleonora; Busana, Mattia; Biancolilli, Osvaldo; Leonardi, Patrizia; Carlin, Andrea; Lonati, Caterina; Panigada, Mauro; Pesenti, Antonio; Zanella, Alberto

    2018-05-01

    Citric acid infusion in extracorporeal blood may allow concurrent regional anticoagulation and enhancement of extracorporeal CO 2 removal. Effects of citric acid on human blood thromboelastography and aggregometry have never been tested before. In this in vitro study, citric acid, sodium citrate and lactic acid were added to venous blood from seven healthy donors, obtaining concentrations of 9 mEq/L, 12 mEq/L and 15 mEq/L. We measured gas analyses, ionized calcium (iCa ++ ) concentration, activated clotting time (ACT), thromboelastography and multiplate aggregometry. Repeated measure analysis of variance was used to compare the acidifying and anticoagulant properties of the three compounds. Sodium citrate did not affect the blood gas analysis. Increasing doses of citric and lactic acid progressively reduced pH and HCO 3 - and increased pCO 2 (p<0.001). Sodium citrate and citric acid similarly reduced iCa ++ , from 0.39 (0.36-0.39) and 0.35 (0.33-0.36) mmol/L, respectively, at 9 mEq/L to 0.20 (0.20-0.21) and 0.21 (0.20-0.23) mmol/L at 15 mEq/L (p<0.001). Lactic acid did not affect iCa ++ (p=0.07). Sodium citrate and citric acid similarly incremented the ACT, from 234 (208-296) and 202 (178-238) sec, respectively, at 9 mEq/L, to >600 sec at 15 mEq/L (p<0.001). Lactic acid did not affect the ACT values (p=0.486). Sodium citrate and citric acid similarly incremented R-time and reduced α-angle and maximum amplitude (MA) (p<0.001), leading to flat-line thromboelastograms at 15 mEq/L. Platelet aggregometry was not altered by any of the three compounds. Citric acid infusions determine acidification and anticoagulation of blood similar to lactic acid and sodium citrate, respectively.

  20. Effect of Periodic Water Addition on Citric Acid Production in Solid State Fermentation

    NASA Astrophysics Data System (ADS)

    Utpat, Shraddha S.; Kinnige, Pallavi T.; Dhamole, Pradip B.

    2013-09-01

    Water addition is one of the methods used to control the moisture loss in solid state fermentation (SSF). However, none of the studies report the timing of water addition and amount of water to be added in SSF. Therefore, this work was undertaken with an objective to evaluate the performance of periodic water addition on citric acid production in SSF. Experiments were conducted at different moistures (50-80 %) and temperatures (30-40 °C) to simulate the conditions in a fermenter. Citric acid production by Aspergillus niger (ATCC 9029) using sugarcane baggase was chosen as a model system. Based on the moisture profile, citric acid and sugar data, a strategy was designed for periodic addition of water. Water addition at 48, 96, 144 and 192 h enhanced the citric acid production by 62 % whereas water addition at 72, 120, and 168 h increased the citric acid production by just 17 %.

  1. Advances in citric acid fermentation by Aspergillus niger: biochemical aspects, membrane transport and modeling.

    PubMed

    Papagianni, Maria

    2007-01-01

    Citric acid is regarded as a metabolite of energy metabolism, of which the concentration will rise to appreciable amounts only under conditions of substantive metabolic imbalances. Citric acid fermentation conditions were established during the 1930s and 1940s, when the effects of various medium components were evaluated. The biochemical mechanism by which Aspergillus niger accumulates citric acid has continued to attract interest even though its commercial production by fermentation has been established for decades. Although extensive basic biochemical research has been carried out with A. niger, the understanding of the events relevant for citric acid accumulation is not completely understood. This review is focused on citric acid fermentation by A. niger. Emphasis is given to aspects of fermentation biochemistry, membrane transport in A. niger and modeling of the production process.

  2. Esterification of pseudoephedrine hydrochloride by citric acid in a solid dose pharmaceutical preparation.

    PubMed

    Goel, Alok; Zhao, Zhicheng; Sørensen, Dan; Zhou, Jay; Zhang, Fa

    2016-09-10

    Esterification of pseudoephedrine hydrochloride (PSE) by citric acid was observed in a solid dose pharmaceutical preparation at room temperature and accelerated stability condition (40°C/75% relative humidity). The esterification of PSE with citric acid was confirmed by a solid-state binary reaction in the presence of minor level of water at elevated temperature to generate three isomeric esters. The structures of the pseudoephedrine citric acid esters were elucidated using high-resolution mass spectrometry and nuclear magnetic resonance spectroscopy (NMR). Occurrence of esterification in solid state, instead of amidation which is generally more favorable than esterification, is likely due to remaining HCl salt form of solid pseudoephedrine hydrochloride to protect its amino group from amidation with citric acid. In contrast, the esterification was not observed from solution reaction between PSE and citric acid. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Method for the isolation of citric acid and malic acid in Japanese apricot liqueur for carbon stable isotope analysis.

    PubMed

    Akamatsu, Fumikazu; Hashiguchi, Tomokazu; Hisatsune, Yuri; Oe, Takaaki; Kawao, Takafumi; Fujii, Tsutomu

    2017-02-15

    A method for detecting the undeclared addition of acidic ingredients is required to control the authenticity of Japanese apricot liqueur. We developed an analytical procedure that minimizes carbon isotope discrimination for measurement of the δ(13)C values of citric and malic acid isolated from Japanese apricot liqueur. Our results demonstrated that freeze-drying is preferable to nitrogen spray-drying, because it does not significantly affect the δ(13)C values of citric acid and results in smaller isotope discrimination for malic acid. Both 0.1% formic acid and 0.2% phosphoric acid are acceptable HPLC mobile phases for the isolation of citric and malic acid, although the δ(13)C values of malic acid exhibited relatively large variation compared with citric acid following isolation using either mobile phase. The developed procedure allows precise δ(13)C measurements of citric and malic acid isolated from Japanese apricot liqueur. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. An investigation into the stability and sterility of citric acid solutions used for cough reflex testing.

    PubMed

    Falconer, James R; Wu, Zimei; Lau, Hugo; Suen, Joanna; Wang, Lucy; Pottinger, Sarah; Lee, Elaine; Alazawi, Nawar; Kallesen, Molly; Gargiulo, Derryn A; Swift, Simon; Svirskis, Darren

    2014-10-01

    Citric acid is used in cough reflex testing in clinical and research settings to assess reflexive cough in patients at risk of swallowing disorders. To address a lack of knowledge in this area, this study investigated the stability and sterility of citric acid solutions. Triplicate solutions of citric acid (0.8 M) in isotonic saline were stored at 4 ± 2 °C for up to 28 days and analysed by high-performance liquid chromatography. Microbiological sterility of freshly prepared samples and bulk samples previously used for 2 weeks within the hospital was determined using a pour plate technique. Microbial survival in citric acid was determined by inoculating Staphylococcus aureus, Escherichia coli, or Candida albicans into citric acid solution and monitoring the number of colony-forming units/mL over 40 min. Citric acid solutions remained stable at 4 °C for 28 days (98.4 ± 1.8 % remained). The freshly prepared and clinical samples tested were sterile. However, viability studies revealed that citric acid solution allows for the survival of C. albicans but not for S. aureus or E. coli. The microbial survival study showed that citric acid kills S. aureus and E. coli but has no marked effect on C. albicans after 40 min. Citric acid samples at 0.8 M remained stable over the 4-week testing period, with viable microbial cells absent from samples tested. However, C. albicans has the ability to survive in citric acid solution if inadvertently introduced in practice. For this reason, in clinical and research practice it is suggested to use single-use aliquots prepared aseptically which can be stored for up to 28 days at 4 °C.

  5. 21 CFR 582.4101 - Diacetyl tartaric acid esters of mono- and diglycerides of edible fats or oils, or edible fat...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... diglycerides of edible fats or oils, or edible fat-forming fatty acids. 582.4101 Section 582.4101 Food and... Diacetyl tartaric acid esters of mono- and diglycerides of edible fats or oils, or edible fat-forming fatty... edible fat-forming fatty acids. (b) Conditions of use. This substance is generally recognized as safe...

  6. 21 CFR 582.4101 - Diacetyl tartaric acid esters of mono- and diglycerides of edible fats or oils, or edible fat...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... diglycerides of edible fats or oils, or edible fat-forming fatty acids. 582.4101 Section 582.4101 Food and... Diacetyl tartaric acid esters of mono- and diglycerides of edible fats or oils, or edible fat-forming fatty... edible fat-forming fatty acids. (b) Conditions of use. This substance is generally recognized as safe...

  7. Transcriptome mining and in silico structural and functional analysis of ascorbic acid and tartaric acid biosynthesis pathway enzymes in rose-scanted geranium.

    PubMed

    Narnoliya, Lokesh K; Sangwan, Rajender S; Singh, Sudhir P

    2018-06-01

    Rose-scented geranium (Pelargonium sp.) is widely known as aromatic and medicinal herb, accumulating specialized metabolites of high economic importance, such as essential oils, ascorbic acid, and tartaric acid. Ascorbic acid and tartaric acid are multifunctional metabolites of human value to be used as vital antioxidants and flavor enhancing agents in food products. No information is available related to the structural and functional properties of the enzymes involved in ascorbic acid and tartaric acid biosynthesis in rose-scented geranium. In the present study, transcriptome mining was done to identify full-length genes, followed by their bioinformatic and molecular modeling investigations and understanding of in silico structural and functional properties of these enzymes. Evolutionary conserved domains were identified in the pathway enzymes. In silico physicochemical characterization of the catalytic enzymes revealed isoelectric point (pI), instability index, aliphatic index, and grand average hydropathy (GRAVY) values of the enzymes. Secondary structural prediction revealed abundant proportion of alpha helix and random coil confirmations in the pathway enzymes. Three-dimensional homology models were developed for these enzymes. The predicted structures showed significant structural similarity with their respective templates in root mean square deviation analysis. Ramachandran plot analysis of the modeled enzymes revealed that more than 84% of the amino acid residues were within the favored regions. Further, functionally important residues were identified corresponding to catalytic sites located in the enzymes. To, our best knowledge, this is the first report which provides a foundation on functional annotation and structural determination of ascorbic acid and tartaric acid pathway enzymes in rose-scanted geranium.

  8. Optimization of the 3-Point Bending Failure of Anodized Aluminum Formed in Tartaric/Sulphuric Acid Using Doehlert Design

    NASA Astrophysics Data System (ADS)

    Bensalah, W.; Feki, M.; De-Petris Wery, M.; Ayedi, H. F.

    2015-02-01

    The bending failure of anodized aluminum in tartaric/sulphuric acid bath was modeled using Doehlert design. Bath temperature, anodic current density, sulphuric acid, and tartaric acid concentrations were retained as variables. Thickness measurements and 3-point bending experiments were conducted. The deflection at failure ( D f) and the maximum load ( F m) of each sample were, then, deducted from the corresponding flexural responses. The treatment of experimental results has established mathematical models of second degree reflecting the relation of cause and effect between the factors and the studied properties. The optimum path study of thickness, deflection at failure, and maximum load, showed that the three optima were opposite. Multicriteria optimization using the desirability function was achieved in order to maximize simultaneously the three responses. The optimum conditions were: C tar = 18.2 g L-1, T = 17.3 °C, J = 2.37 A dm-2, C sul = 191 g L-1, while the estimated response values were e = 57.7 µm, D f = 5.6 mm, and F m = 835 N. Using the established models, a mathematical correlation was found between deflection at failure and thickness of the anodic oxide layer. Before bending tests, aluminum oxide layer was examined by scanning electron microscopy (SEM) and atomic force microscopy. After tests, the morphology and the composition of the anodic oxide layer were inspected by SEM, optical microscopy, and glow-discharge optical emission spectroscopy.

  9. 77 FR 47370 - Citric Acid and Certain Citrate Salts from the People's Republic of China: Intent To Rescind...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-08

    ... order includes all grades and granulation sizes of citric acid, sodium citrate, and potassium citrate in... includes blends of citric acid, sodium citrate, and potassium citrate; as well as blends with other ingredients, such as sugar, where the unblended form(s) of citric acid, sodium citrate, and potassium citrate...

  10. 77 FR 56188 - Citric Acid and Certain Citrate Salts from the People's Republic of China: Notice of Rescission...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-12

    ... the order includes all grades and granulation sizes of citric acid, sodium citrate, and potassium... also includes blends of citric acid, sodium citrate, and potassium citrate; as well as blends with other ingredients, such as sugar, where the unblended form(s) of citric acid, sodium citrate, and...

  11. 77 FR 72323 - Citric Acid and Certain Citrate Salts From the People's Republic of China: Final Results of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-05

    ... DEPARTMENT OF COMMERCE International Trade Administration [C-570-938] Citric Acid and Certain... countervailing duty (CVD) order on citric acid and certain citrate salts from the People's Republic of China for... results of this review.\\1\\ \\1\\ See Citric Acid and Certain Citrate Salts from the People's Republic of...

  12. 76 FR 17835 - Citric Acid and Certain Citrate Salts From the People's Republic of China: Extension of Time...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-31

    ... DEPARTMENT OF COMMERCE International Trade Administration A-570-937] Citric Acid and Certain... initiation of the administrative review of the antidumping duty order on citric acid and certain citrate salts (``citric acid'') from the People's Republic of China (``PRC''). See Initiation of Antidumping and...

  13. 77 FR 9891 - Citric Acid and Certain Citrate Salts from the People's Republic of China: Amended Final Results...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-21

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-570-937] Citric Acid and Certain... the final results of the first administrative review of the antidumping duty order on citric acid and certain citrate salts (``citric acid'') from the People's Republic of China (``PRC'').\\1\\ The period of...

  14. 76 FR 56158 - Citric Acid and Certain Citrate Salts From the People's Republic of China: Extension of Time...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-12

    ... DEPARTMENT OF COMMERCE International Trade Administration [C-570-938] Citric Acid and Certain... preliminary results of the administrative review of the countervailing duty order on citric acid and certain..., 2009. See Citric Acid and Certain Citrate Sales from the People's Republic of China: Preliminary...

  15. 76 FR 4288 - Citric Acid and Certain Citrate Salts From the People's Republic of China: Notice of Extension of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-25

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-570-937] Citric Acid and Certain...'') published the initiation of the administrative review of the antidumping duty order on citric acid and certain citrate salts (``citric acid'') from the People's Republic of China (``PRC''). See Initiation of...

  16. 76 FR 82275 - Citric Acid and Certain Citrate Salts From the People's Republic of China: Extension of Time...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-30

    ... DEPARTMENT OF COMMERCE International Trade Administration [C-570-938] Citric Acid and Certain...) published in the Federal Register the countervailing duty order on citric acid and certain citrate salts... Affirmative Countervailing Duty Determinations: Citric Acid and Certain Citrate Salts, 74 FR 25705 (May 29...

  17. Citric acid production in Yarrowia lipolytica SWJ-1b yeast when grown on waste cooking oil.

    PubMed

    Liu, Xiaoyan; Lv, Jinshun; Xu, Jiaxing; Zhang, Tong; Deng, Yuanfang; He, Jianlong

    2015-03-01

    In this study, citric acid was produced from waste cooking oil by Yarrowia lipolytica SWJ-1b. To get the maximal yield of citric acid, the compositions of the medium for citric acid production were optimized, and our results showed that extra nitrogen and magnesium rather than vitamin B1 and phosphate were needed for CA accumulation when using waste cooking oil. The results also indicated that the optimal initial concentration of the waste cooking oil in the medium for citric acid production was 80.0 g/l, and the ideal inoculation size was 1 × 10(7) cells/l of medium. We also reported that during 10-l fermentation, 31.7 g/l of citric acid, 6.5 g/l of isocitric acid, 5.9 g/l of biomass, and 42.1 g/100.0 g cell dry weight of lipid were attained from 80.0 g/l of waste cooking oil within 336 h. At the end of the fermentation, 94.6 % of the waste cooking oil was utilized by the cells of Y. lipolytica SWJ-1b, and the yield of citric acid was 0.4 g/g waste cooking oil, which suggested that waste cooking oil was a suitable carbon resource for citric acid production.

  18. Citric acid effects on brain and liver oxidative stress in lipopolysaccharide-treated mice.

    PubMed

    Abdel-Salam, Omar M E; Youness, Eman R; Mohammed, Nadia A; Morsy, Safaa M Youssef; Omara, Enayat A; Sleem, Amany A

    2014-05-01

    Citric acid is a weak organic acid found in the greatest amounts in citrus fruits. This study examined the effect of citric acid on endotoxin-induced oxidative stress of the brain and liver. Mice were challenged with a single intraperitoneal dose of lipopolysaccharide (LPS; 200 μg/kg). Citric acid was given orally at 1, 2, or 4 g/kg at time of endotoxin injection and mice were euthanized 4 h later. LPS induced oxidative stress in the brain and liver tissue, resulting in marked increase in lipid peroxidation (malondialdehyde [MDA]) and nitrite, while significantly decreasing reduced glutathione, glutathione peroxidase (GPx), and paraoxonase 1 (PON1) activity. Tumor necrosis factor-alpha (TNF-α) showed a pronounced increase in brain tissue after endotoxin injection. The administration of citric acid (1-2 g/kg) attenuated LPS-induced elevations in brain MDA, nitrite, TNF-α, GPx, and PON1 activity. In the liver, nitrite was decreased by 1 g/kg citric acid. GPx activity was increased, while PON1 activity was decreased by citric acid. The LPS-induced liver injury, DNA fragmentation, serum transaminase elevations, caspase-3, and inducible nitric oxide synthase expression were attenuated by 1-2 g/kg citric acid. DNA fragmentation, however, increased after 4 g/kg citric acid. Thus in this model of systemic inflammation, citric acid (1-2 g/kg) decreased brain lipid peroxidation and inflammation, liver damage, and DNA fragmentation.

  19. Citric Acid Effects on Brain and Liver Oxidative Stress in Lipopolysaccharide-Treated Mice

    PubMed Central

    Youness, Eman R.; Mohammed, Nadia A.; Morsy, Safaa M. Youssef; Omara, Enayat A.; Sleem, Amany A.

    2014-01-01

    Abstract Citric acid is a weak organic acid found in the greatest amounts in citrus fruits. This study examined the effect of citric acid on endotoxin-induced oxidative stress of the brain and liver. Mice were challenged with a single intraperitoneal dose of lipopolysaccharide (LPS; 200 μg/kg). Citric acid was given orally at 1, 2, or 4 g/kg at time of endotoxin injection and mice were euthanized 4 h later. LPS induced oxidative stress in the brain and liver tissue, resulting in marked increase in lipid peroxidation (malondialdehyde [MDA]) and nitrite, while significantly decreasing reduced glutathione, glutathione peroxidase (GPx), and paraoxonase 1 (PON1) activity. Tumor necrosis factor-alpha (TNF-α) showed a pronounced increase in brain tissue after endotoxin injection. The administration of citric acid (1–2 g/kg) attenuated LPS-induced elevations in brain MDA, nitrite, TNF-α, GPx, and PON1 activity. In the liver, nitrite was decreased by 1 g/kg citric acid. GPx activity was increased, while PON1 activity was decreased by citric acid. The LPS-induced liver injury, DNA fragmentation, serum transaminase elevations, caspase-3, and inducible nitric oxide synthase expression were attenuated by 1–2 g/kg citric acid. DNA fragmentation, however, increased after 4 g/kg citric acid. Thus in this model of systemic inflammation, citric acid (1–2 g/kg) decreased brain lipid peroxidation and inflammation, liver damage, and DNA fragmentation. PMID:24433072

  20. Citric Acid Production by Aspergillus niger Cultivated on Parkia biglobosa Fruit Pulp

    PubMed Central

    Abidoye, Khadijat Toyin; Tahir, Hauwa; Ibrahim, Aliyu Dabai; Aransiola, Sesan Abiodun

    2014-01-01

    The study was conducted to investigate the potential of Parkia biglobosa fruit pulp as substrate for citric acid production by Aspergillus niger. Reducing sugar was estimated by 3,5-dinitrosalicylic acid and citric acid was estimated spectrophotometrically using pyridine-acetic anhydride methods. The studies revealed that production parameters (pH, inoculum size, substrate concentration, incubation temperature, and fermentation period) had profound effect on the amount of citric acid produced. The maximum yield was obtained at the pH of 2 with citric acid of 1.15 g/L and reducing sugar content of 0.541 mMol−1, 3% vegetative inoculum size with citric acid yield of 0.53 g/L and reducing sugar content of 8.87 mMol−1, 2% of the substrate concentration with citric acid yield of 0.83 g/L and reducing sugar content of 9.36 mMol−1, incubation temperature of 55°C with citric acid yield of 0.62 g/L and reducing sugar content of 8.37 mMol−1, and fermentation period of 5 days with citric acid yield of 0.61 g/L and reducing sugar content of 3.70 mMol−1. The results of this study are encouraging and suggest that Parkia biglobosa pulp can be harnessed at low concentration for large scale citric acid production. PMID:27433535

  1. Morphological regulation of Aspergillus niger to improve citric acid production by chsC gene silencing.

    PubMed

    Sun, Xiaowen; Wu, Hefang; Zhao, Genhai; Li, Zhemin; Wu, Xihua; Liu, Hui; Zheng, Zhiming

    2018-04-02

    The mycelial morphology of Aspergillus niger, a major filamentous fungus used for citric acid production, is important for citric acid synthesis during submerged fermentation. To investigate the involvement of the chitin synthase gene, chsC, in morphogenesis and citric acid production in A. niger, an RNAi system was constructed to silence chsC and the morphological mutants were screened after transformation. The compactness of the mycelial pellets was obviously reduced in the morphological mutants, with lower proportion of dispersed mycelia. These morphological changes have caused a decrease in viscosity and subsequent improvement in oxygen and mass transfer efficiency, which may be conducive for citric acid accumulation. All the transformants exhibited improvements in citric acid production; in particular, chsC-3 showed 42.6% higher production than the original strain in the shake flask. Moreover, the high-yield strain chsC-3 exhibited excellent citric acid production potential in the scale-up process.The citric acid yield and the conversion rate of glucose of chsC-3 were both improved by 3.6%, when compared with that of the original strain in the stirred tank bioreactor.

  2. Optimization of the integrated citric acid-methane fermentation process by air stripping and glucoamylase addition.

    PubMed

    Xu, Jian; Chen, Yang-Qiu; Zhang, Hong-Jian; Wang, Ke; Tang, Lei; Zhang, Jian-Hua; Chen, Xu-Sheng; Mao, Zhong-Gui

    2015-03-01

    To solve the problem of extraction wastewater in citric acid industry, an integrated citric acid-methane fermentation process was proposed. In the integrated process, extraction wastewater was treated by mesophilic anaerobic digestion and then reused to make mash for the next batch of citric acid fermentation. In this study, an Aspergillus niger mutant strain exhibiting resistance to high metal ions concentration was used to eliminate the inhibition of 200 mg/L Na(+) and 300 mg/L K(+) in anaerobic digestion effluent (ADE) and citric acid production increased by 25.0 %. Air stripping was used to remove ammonium, alkalinity, and part of metal ions in ADE before making mash. In consequence, citric acid production was significantly improved but still lower by 6.1 % than the control. Results indicated that metal ions in ADE synergistically inhibited the activity of glucoamylase, thus reducing citric acid production. When 130 U/g glucoamylase was added before fermentation, citric acid production was 141.5 g/L, which was even higher than the control (140.4 g/L). This process could completely eliminate extraction wastewater discharge and reduce water resource consumption.

  3. Citric Acid Suppresses the Bitter Taste of Olopatadine Hydrochloride Orally Disintegrating Tablets.

    PubMed

    Sotoyama, Mai; Uchida, Shinya; Tanaka, Shimako; Hakamata, Akio; Odagiri, Keiichi; Inui, Naoki; Watanabe, Hiroshi; Namiki, Noriyuki

    2017-01-01

    Orally disintegrating tablets (ODTs) are formulated to disintegrate upon contact with saliva, allowing administration without water. Olopatadine hydrochloride, a second-generation antihistamine, is widely used for treating allergic rhinitis. However, it has a bitter taste; therefore, the development of taste-masked olopatadine ODTs is essential. Some studies have suggested that citric acid could suppress the bitterness of drugs. However, these experiments were performed using solutions, and the taste-masking effect of citric acid on ODTs has not been evaluated using human gustatory sensation tests. Thus, this study evaluated citric acid's taste-masking effect on olopatadine ODTs. Six types of olopatadine ODTs containing 0-10% citric acid were prepared and subjected to gustatory sensation tests that were scored using the visual analog scale. The bitterness and overall palatability of olopatadine ODTs during disintegration in the mouth and after spitting out were evaluated in 11 healthy volunteers (age: 22.8±2.2 years). The hardness of the ODTs was >50 N. Disintegration time and dissolution did not differ among the different ODTs. The results of the gustatory sensation tests suggest that citric acid could suppress the bitterness of olopatadine ODTs in a dose-dependent manner. Olopatadine ODTs with a high content of citric acid (5-10%) showed poorer overall palatability than that of those without citric acid despite the bitterness suppression. ODTs containing 2.5% citric acid, yogurt flavoring, and aspartame were the most suitable formulations since they showed low bitterness and good overall palatability. Thus, citric acid is an effective bitterness-masking option for ODTs.

  4. Yarrowia lipolytica: a model yeast for citric acid production.

    PubMed

    Cavallo, Ema; Charreau, Hernán; Cerrutti, Patricia; Foresti, María Laura

    2017-12-01

    Every year more than 2 million tons of citric acid (CA) are produced around the world for industrial uses. Although initially extracted from citrus, the low profitability of the process and the increasing demand soon stimulated the search for more efficient methods to produce CA. Currently, most world CA demand (99%) is satisfied by fermentations with microorganisms, especially filamentous fungi and yeasts. CA production with yeasts has certain advantages over molds (e.g. higher productivity and easier cultivation), which in the last two decades have triggered a clear increase in publications and patents devoted to the use of yeasts in this field. Yarrowia lipolytica has become a model yeast that proved to be successful in different production systems. Considering the current interest evidenced in the literature, the most significant information on CA production using Y. lipolytica is summarized. The relevance on CA yields of key factors such as strains, media formulation, environmental conditions and production regimes is thoroughly discussed, with particular focus on increasing CA productivity. Besides, the possibility of tuning the mentioned variables to reduce concomitant isocitric acid production-the biggest disadvantage of using yeasts-is analyzed. Available methods for CA purification/quantification are also discussed. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  5. Citric acid-modified Fenton's reaction for the oxidation of chlorinated ethylenes in soil solution systems.

    PubMed

    Seol, Yongkoo; Javandel, Iraj

    2008-06-01

    Fenton's reagent, a solution of hydrogen peroxide and ferrous iron catalyst, is used for an in situ chemical oxidation of organic contaminants. Sulfuric acid is commonly used to create an acidic condition needed for catalytic oxidation. Fenton's reaction often involves pressure buildup and precipitation of reaction products, which can cause safety hazards and diminish efficiency. We selected citric acid, a food-grade substance, as an acidifying agent to evaluate its efficiencies for organic contaminant removal in Fenton's reaction, and examined the impacts of using citric acid on the unwanted reaction products. A series of batch and column experiments were performed with varying H2O2 concentrations to decompose selected chlorinated ethylenes. Either dissolved iron from soil or iron sulfate salt was added to provide the iron catalyst in the batch tests. Batch experiments revealed that both citric and sulfuric acid systems achieved over 90% contaminant removal rates, and the presence of iron catalyst was essential for effective decontamination. Batch tests with citric acid showed no signs of pressure accumulation and solid precipitations, however the results suggested that an excessive usage of H2O2 relative to iron catalysts (Fe2+/H2O2<1/330) would result in lowering the efficiency of contaminant removal by iron chelation in the citric acid system. Column tests confirmed that citric acid could provide suitable acidic conditions to achieve higher than 55% contaminant removal rates.

  6. Changes in the physiological properties and kinetics of citric acid accumulation via carbon ion irradiation mutagenesis of Aspergillus niger *

    PubMed Central

    Hu, Wei; Chen, Ji-hong; Wang, Shu-yang; Liu, Jing; Song, Yuan; Wu, Qing-feng; Li, Wen-jian

    2016-01-01

    The objective of this work was to produce citric acid from corn starch using a newly isolated mutant of Aspergillus niger, and to analyze the relationship between changes in the physiological properties of A. niger induced by carbon ion irradiation and citric acid accumulation. Our results showed that the physiological characteristics of conidia in A. niger were closely related to citric acid accumulation and that lower growth rate and viability of conidia may be beneficial to citric acid accumulation. Using corn starch as a raw material, a high-yielding citric acid mutant, named HW2, was obtained. In a 10-L bioreactor, HW2 can accumulate 118.9 g/L citric acid with a residual total sugar concentration of only 14.4 g/L. This represented an 18% increase in citric acid accumulation and a 12.5% decrease in sugar utilization compared with the original strain.

  7. Tartaric Acid as a Non-toxic and Environmentally-Friendly Anti-scaling Material for Using in Cooling Water Systems: Electrochemical and Surface Studies

    NASA Astrophysics Data System (ADS)

    Asghari, Elnaz; Gholizadeh-Khajeh, Maryam; Ashassi-Sorkhabi, Habib

    2016-10-01

    Because of the major limitations in drinking water resources, the industries need to use unprocessed water sources for their cooling systems; these water resources contain major amount of hardening cations. So, mineral scales are formed in cooling water systems during the time and cause major problems. The use of green anti-scaling materials such as carboxylic acids is considered due to their low risks of environmental pollution. In the present work, the scale inhibition performance of tartaric acid as a green organic material was evaluated. Chemical screening tests, cathodic and anodic voltammetry measurements and electrochemical impedance spectroscopy (EIS), field emission scanning electron microscopy (FESEM), energy-dispersive x-ray and x-ray diffraction, were used for the evaluation of the scale inhibition performance. The results showed that tartaric acid can prevent calcium carbonate precipitation significantly. The hard water solution with 2.0 mM of tartaric acid indicated the highest scale inhibition efficiency (ca. 68%). The voltammetry, EIS and FESEM results verified that tartaric acid can form smooth and homogeneous film on steel surface through formation of Fe(III)-tartrate complexes and retard the local precipitation of calcium carbonate deposits.

  8. Citric acid functionalized carbon materials for fuel cell applications

    NASA Astrophysics Data System (ADS)

    Poh, Chee Kok; Lim, San Hua; Pan, Hui; Lin, Jianyi; Lee, Jim Yang

    Carbon materials can be easily functionalized using citric acid (CA) treatment. The CA modification of carbon materials is both simple and effective. It requires no prolonged heating, filtration and washing, and produces more functional groups such as carboxyl and hydroxide on CA-modified carbon nanotubes and XC72 carbon blacks than on HNO 3-H 2SO 4 oxidized carbon nanotubes and as-purchased XC72. Platinum nanoparticles are deposited on these functionalized carbon materials by means of a microwave-assisted polyol process. The investigations using TEM, XRD, FTIR and TGA indicate that CA modification creates more functional groups and thus deposits more Pt nanoparticles with smaller average particle size on the surface of carbon materials. Electrochemical studies of the Pt/C samples for methanol oxidation reveal higher activity for Pt on CA-modified carbon materials. It is therefore considered that this method can find important applications in reducing the cost and improving performance of proton-exchange membrane fuel cells.

  9. Stoichiometry of Reducing Equivalents and Splitting of Water in the Citric Acid Cycle.

    ERIC Educational Resources Information Center

    Madeira, Vitor M. C.

    1988-01-01

    Presents a solution to the problem of finding the source of extra reducing equivalents, and accomplishing the stoichiometry of glucose oxidation reactions. Discusses the citric acid cycle and glycolysis. (CW)

  10. Citric acid production by Koji fermentation using banana peel as a novel substrate.

    PubMed

    Karthikeyan, Alagarsamy; Sivakumar, Nallusamy

    2010-07-01

    The growing demand for citric acid and the current need for alternative sources have encouraged biotechnologists to search for novel and economical substrates. Koji fermentation was conducted using the peels of banana (Musa acuminata) as an inexpensive substrate for the production of citric acid using Aspergillus niger. Various crucial parameters that affect citric acid production such as moisture content, temperature, pH, inoculum level and incubation time were quantified. Moisture (70%), 28 degrees C temperature, an initial pH 3, 10(8) spores/ml as inoculum and 72h incubation was found to be suitable for maximum citric acid production by A. niger using banana peel as a substrate. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  11. Improved flotation performance of hematite fines using citric acid as a dispersant

    NASA Astrophysics Data System (ADS)

    Luo, Xi-mei; Yin, Wan-zhong; Sun, Chuan-yao; Wang, Nai-ling; Ma, Ying-qiang; Wang, Yun-fan

    2016-10-01

    In this study, citric acid was used as a dispersant to improve the flotation performance of hematite fines. The effect and mechanism of citric acid on the reverse flotation of hematite fines were investigated by flotation tests, sedimentation experiments, scanning electron microscopy (SEM), zeta-potential measurements, and X-ray photoelectron spectroscopy (XPS). The results of SEM analysis and flotation tests reveal that a strong heterocoagulation in the form of slime coating or coagulation in hematite fine slurry affects the beneficiation of hematite ores by froth flotation. The addition of a small amount of citric acid (less than 300 g/t) favorably affects the reverse flotation of hematite fines by improving particle dispersion. The results of sedimentation experiments, zeta-potential measurements, and XPS measurements demonstrate that citric acid adsorbs onto hematite and quartz surfaces via hydrogen bonding, thereby reducing the zeta potentials of mineral surfaces, strengthening the electrical double-layer repulsion between mineral particles, and dispersing the pulp particles.

  12. The global regulator LaeA controls production of citric acid and endoglucanases in Aspergillus carbonarius.

    PubMed

    Linde, Tore; Zoglowek, Marta; Lübeck, Mette; Frisvad, Jens Christian; Lübeck, Peter Stephensen

    2016-08-01

    The global regulatory protein LaeA is known for regulating the production of many kinds of secondary metabolites in Aspergillus species, as well as sexual and asexual reproduction, and morphology. In Aspergillus carbonarius, it has been shown that LaeA regulates production of ochratoxin. We have investigated the regulatory effect of LaeA on production of citric acid and cellulolytic enzymes in A. carbonarius. Two types of A. carbonarius strains, having laeA knocked out or overexpressed, were constructed and tested in fermentation. The knockout of laeA significantly decreased the production of citric acid and endoglucanases, but did not reduce the production of beta-glucosidases or xylanases. The citric acid accumulation was reduced with 74-96 % compared to the wild type. The endoglucanase activity was reduced with 51-78 %. Overexpression of LaeA seemed not to have an effect on citric acid production or on cellulose or xylanase activity.

  13. Use of Energy Crop (Ricinus communis L.) for Phytoextraction of Heavy Metals Assisted with Citric Acid.

    PubMed

    Zhang, Hui; Chen, Xueping; He, Chiquan; Liang, Xia; Oh, Kokyo; Liu, Xiaoyan; Lei, Yanru

    2015-01-01

    Ricinus communis L. is a bioenergetic crop with high-biomass production and tolerance to cadmium (Cd) and lead (Pb), thus, the plant is a candidate crop for phytoremediation. Pot experiments were performed to study the effects of citric acid in enhancing phytoextraction of Cd/Pb by Ricinus communis L. Citric acid increased Cd and Pb contents in plant shoots in all treatments by about 78% and 18-45%, respectively, at the dosage of 10 mM kg(-1) soil without affecting aboveground biomass production. Addition of citric acid reduced CEC, weakened soil adsorption of heavy metals and activated Cd and Pb in soil solutions. The acid-exchangeable fraction (BCR-1) of Pb remained lower than 7% and significantly increased with citric acid amendment. Respective increases in soil evaluation index induces by 14% and 19% under the Cd1Pb50 and Cd1Pb250 treatments upon addition of citric acid resulted in soil quality improvement. Ricinus communis L. has great potential in citric acid-assisted phytoextraction for Cd and Pb remediation.

  14. The impact of harmfulness information on citric acid induced cough and urge-to-cough.

    PubMed

    Janssens, Thomas; Brepoels, Sarah; Dupont, Lieven; Van den Bergh, Omer

    2015-04-01

    The cough reflex is an automatic protective reflex, which can be modulated by conscious effort or other forms of top-down control. In this experiment, we investigated whether information about harmfulness of a cough-inducing substance would augment cough reflex sensitivity and associated urge-to-cough. Healthy participants (N = 39) were randomized to receive information that they were to inhale a harmless substance (natural citric acid), or a potentially harmful substance (a potent agro-chemical acid). Using dosimeter-controlled inhalations, the dose of citric acid eliciting at least three coughs (C3) was determined. Next, participants received 4 blocks of randomized presentations of citric acid at the C3 dose, a sub-threshold dose of citric acid and saline control. C3 was reached for 27/39 participants, and C3 thresholds were not influenced by harmfulness information. During repeated citric acid presentations, framing the cough-inducing substance as a potentially harmful chemical resulted in a greater urge-to-cough compared to information framing it as natural citric acid (p < .01). The experimental manipulation did not influence cough frequencies. Our findings show that harmfulness information influences urge-to-cough, corroborating the role of cortical mechanisms in modulating the urge-to-cough and suggesting that cognitive manipulations may contribute to cough treatment. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Effect of citric acid on the acidification of artificial pepsin solution for metacercariae isolation from fish.

    PubMed

    Kim, Min-Ki; Pyo, Kyoung-Ho; Hwang, Young-Sang; Chun, Hyang Sook; Park, Ki Hwan; Ko, Seong-Hee; Chai, Jong-Yil; Shin, Eun-Hee

    2013-11-15

    Artificial digestive solution based on pepsin is essential for collecting metacercariae from fish. To promote the enzymatic reactivity of pepsin, the pH of the solution has to be adjusted to pH 1.0-2.0. Hydrochloride (HCl) is usually used for this purpose, but the use of HCl raises safety concerns. The aim of this work was to address the usefulness of citric acid as an alternative for HCl for the acidification of pepsin solution, and to examine its potential to damage metacercariae during in vitro digestion as compared with HCl. Changes in pH after adding 1-9% of citric acid (m/v) to pepsin solution were compared to a 1% HCl (v/v) addition. Digestion of fish muscle was evaluated by measuring released protein concentrations by spectrophotometry. In addition, survival rates of metacercariae in pepsin solution were determined at different citric acid concentrations and were compared that of with 1% HCl. The present study shows that addition of citric acid reduced the pH of pepsin solutions to the required level. Addition of more than 5% of citric acid resulted in the effective digestion of fish muscle over 3h in vitro, and 5% citric acid was less lethal to metacercariae than 1% HCl in pepsin solution. Pepsin solution containing 5% citric acid had digestive capacity superior to pepsin solution containing 1% HCl after 3h incubation with released protein concentrations of 12.0 ng/ml for 5% citric acid and 9.6 ng/ml for 1% HCl. Accordingly, the present study suggests that the addition of 5% citric acid to pepsin solution is a good alternative to 1% HCl in infection studies because citric acid is a stable at room temperature and has a good safety profile. In addition, we suggest that the use of citric acid enables the preparation of commercial digestive solutions for the detection of microorganisms in fish and other vertebrate muscle tissue. Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

  16. Identification of oxalic acid and tartaric acid as major persistent pain-inducing toxins in the stinging hairs of the nettle, Urtica thunbergiana.

    PubMed

    Fu, Han Yi; Chen, Shiang Jiuun; Chen, Ruei Feng; Ding, Wang Hsien; Kuo-Huang, Ling Long; Huang, Rong Nan

    2006-07-01

    Once human skin contacts stinging hairs of Urtica spp. (stinging nettles), the irritant is released and produces pain, wheals or a stinging sensation which may last for >12 h. However, the existence of pain-inducing toxins in the stinging hairs of Urtica thunbergiana has never been systematically demonstrated. Experiments were therefore conducted to identify the persistent pain-inducing agents in the stinging hairs of U. thunbergiana. The stinging hairs of U. thunbergiana were removed and immersed in deionized water. After centrifugation, the clear supernatants were then subjected to high-performance liquid chromatography (HPLC), enzymatic analysis and/or behavioural bioassays. The HPLC results showed that the major constituents in the stinging hairs of U. thunbergiana were histamine, oxalic acid and tartaric acid. However, the well-recognized pain-inducing agents, serotonin and formic acid, existed at a low concentration as estimated by HPLC and/or enzymatic analyses. The behavioural tests showed that 2% oxalic acid and 10% tartaric acid dramatically elicited persistent pain sensations in rats. In contrast, 10% formic acid and 2% serotonin only elicited moderate pain sensation in the first 10 min. Moreover, no significant pain-related behavioural response was observed after injecting 10% acetylcholine and histamine in rats. Oxalic acid and tartaric acid were identified, for the first time, as major long-lasting pain-inducing toxins in the stinging hairs of U. thunbergiana. The general view that formic acid, histamine and serotonin are the pain-inducing agents in the stinging hairs of U. dioica may require updating, since their concentrations in U. thunbergiana were too low to induce significant pain sensation in behavioural bioassays.

  17. The Scale Formation of Barite (BaSO4) from Laminar Flowing Water in The Presence of Tartaric Acid and Ba2+ Concentration Variation of Solution

    NASA Astrophysics Data System (ADS)

    Fatra, F.; Ivanto, G.; Dera, N. S.; Muryanto, S.; Bayuseno, A. P.

    2017-05-01

    The barite (BaSO4) scale is a mineral deposit that can be precipitated during the process of drilling oil and gas in the offshore. Deposite scale in pipes can cause a narrowing of the diameter of pipes, and can reduce water flowing in the pipe. The aim of this study is to investigation the effect of the tartaric acid additive and Ba2+ concentration on the growth o the scale formation of barite in the laminar flow of the piping system. Solution forming barite crystal was prepared by mixing equimolar solutions of barium chloride (BaCl2) and sodium sulfate (Na2SO4) with concentration variations of Ba2+ of 3000, 3500, 4000, 4500, and 5000 ppm. The flow rate of solution is 40 ml/min at temperature of 50 °C. Various concentrations of tartaric acid (C4H6O6) of 0 ppm, 5 ppm and 10 ppm were added to the solutions. The formation of barite from the solution was observed by ion conductivity measurement. The obtained barite crystals before and after adding tartaric acid were dried and characterized by using SEM/EDX for morphology and elemental analysis, and XRD for phase identification. The SEM results show that the morphology of the crystals are star-like particles, while XRD analysis confirmed that the barite crystals were produced during the experiments are high purity. Moreover, the tartaric acid can inhibit the crystal growth of barite.

  18. Citric acid assisted phytoremediation of copper by Brassica napus L.

    PubMed

    Zaheer, Ihsan Elahi; Ali, Shafaqat; Rizwan, Muhammad; Farid, Mujahid; Shakoor, Muhammad Bilal; Gill, Rafaqa Ali; Najeeb, Ullah; Iqbal, Naeem; Ahmad, Rehan

    2015-10-01

    Use of organic acids for promoting heavy metals phytoextraction is gaining worldwide attention. The present study investigated the influence of citric acid (CA) in enhancing copper (Cu) uptake by Brassica napus L. seedlings. 6 Weeks old B. napus seedlings were exposed to different levels of copper (Cu, 0, 50 and 100µM) alone or with CA (2.5mM) in a nutrient medium for 40 days. Exposure to elevated Cu levels (50 and 100µM) significantly reduced the growth, biomass production, chlorophyll content, gas exchange attributes and soluble proteins of B. napus seedlings. In addition, Cu toxicity increased the production of hydrogen peroxide (H2O2), malondialdehyde (MDA) and electrolyte leakage (EL) in leaf and root tissues of B. napus. Activities of antioxidant enzymes such as guaiacol peroxidase (POD), superoxide dismutase (SOD), catalases (CAT), ascorbate peroxidase (APX) in root and shoot tissues of B. napus were increased in response to lower Cu concentration (50µM) but increased under higher Cu concentration (100µM). Addition of CA into nutrient medium significantly alleviated Cu toxicity effects on B. napus seedlings by improving photosynthetic capacity and ultimately plant growth. Increased activities of antioxidant enzymes in CA-treated plants seems to play a role in capturing of stress-induced reactive oxygen species as was evident from lower level of H2O2, MDA and EL in CA-treated plants. Increasing Cu concentration in the nutrient medium significantly increased Cu concentration in in B. napus tissues. Cu uptake was further increased by CA application. These results suggested that CA might be a useful strategy for increasing phytoextraction of Cu from contaminated soils. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. A novel cleaner production process of citric acid by recycling its treated wastewater.

    PubMed

    Xu, Jian; Su, Xian-Feng; Bao, Jia-Wei; Zhang, Hong-Jian; Zeng, Xin; Tang, Lei; Wang, Ke; Zhang, Jian-Hua; Chen, Xu-Sheng; Mao, Zhong-Gui

    2016-07-01

    In this study, a novel cleaner production process of citric acid was proposed to completely solve the problem of wastewater management in citric acid industry. In the process, wastewater from citric acid fermentation was used to produce methane through anaerobic digestion and then the anaerobic digestion effluent was further treated with air stripping and electrodialysis before recycled as process water for the later citric acid fermentation. This proposed process was performed for 10 batches and the average citric acid production in recycling batches was 142.4±2.1g/L which was comparable to that with tap water (141.6g/L). Anaerobic digestion was also efficient and stable in operation. The average chemical oxygen demand (COD) removal rate was 95.1±1.2% and methane yield approached to 297.7±19.8mL/g TCODremoved. In conclusion, this novel process minimized the wastewater discharge and achieved the cleaner production in citric acid industry. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Synthesis, structures and properties of two new chiral rare earth-organic frameworks constructed by L/D-tartaric acid

    SciTech Connect

    Hu, Gonghao; Zhang, Haitao; Miao, Hao

    2015-09-15

    Hydrothermal reactions of rare earth cerium with L- or D- tartaric acid afford a pair of novel chiral enantiomer coordination polymers, namely, [Ce(L-tart)(CH{sub 2}OHCH{sub 2}OH)(H{sub 2}O)]Cl (L-1) and [Ce(D-tart)(CH{sub 2}OHCH{sub 2}OH)(H{sub 2}O)]Cl (D-1). Their structures were determined by single crystal X-ray diffraction analyses and further characterized by elemental analyses, XRD, IR spectra, and TG analyses. The circular dichroism (CD) spectra and second-harmonic generation (SHG) efficiency measurements proved that they are of structural chirality in the bulk samples. To the best of our knowledge, the enantiomers of L-1 and D-1 are the first 2D chiral dilayer frameworks constructed from L/D-tartrate ligands,more » ancillary ligand ethanediol and lanthanide ion Ce. - Graphical abstract: Hydrothermal reactions of rare earth cerium with L- or D- tartaric acid afford a pair of novel chiral enantiomer coordination polymers, namely, [Ce(L-tart)(CH{sub 2}OHCH{sub 2}OH)(H{sub 2}O)]Cl (L-1) and [Ce(D-tart)(CH{sub 2}OHCH{sub 2}OH)(H{sub 2}O)]Cl (D-1). Structural analysis indicates that the enantiomers of L-1 and D-1 are the first 2D chiral dilayer frameworks constructed from L/D-tartrate ligands and ancillary ligands ethanediol reacted with lanthanide ions Ce.« less

  1. Quantitative Determination of Citric and Ascorbic Acid in Powdered Drink Mixes

    ERIC Educational Resources Information Center

    Sigmann, Samuella B.; Wheeler, Dale E.

    2004-01-01

    A procedure by which the reactions are used to quantitatively determine the amount of total acid, the amount of total ascorbic acid and the amount of citric acid in a given sample of powdered drink mix, are described. A safe, reliable and low-cost quantitative method to analyze consumer product for acid content is provided.

  2. Multiple Glass Transitions and Freezing Events of Aqueous Citric Acid

    PubMed Central

    2014-01-01

    Calorimetric and optical cryo-microscope measurements of 10–64 wt % citric acid (CA) solutions subjected to moderate (3 K/min) and slow (0.5 and 0.1 K/min) cooling/warming rates and also to quenching/moderate warming between 320 and 133 K are presented. Depending on solution concentration and cooling rate, the obtained thermograms show one freezing event and from one to three liquid–glass transitions upon cooling and from one to six liquid–glass and reverse glass–liquid transitions, one or two freezing events, and one melting event upon warming of frozen/glassy CA/H2O. The multiple freezing events and glass transitions pertain to the mother CA/H2O solution itself and two freeze-concentrated solution regions, FCS1 and FCS2, of different concentrations. The FCS1 and FCS2 (or FCS22) are formed during the freezing of CA/H2O upon cooling and/or during the freezing upon warming of partly glassy or entirely glassy mother CA/H2O. The formation of two FCS1 and FCS22 regions during the freezing upon warming to our best knowledge has never been reported before. Using an optical cryo-microscope, we are able to observe the formation of a continuous ice framework (IF) and its morphology and reciprocal distribution of IF/(FCS1 + FCS2). Our results provide a new look at the freezing and glass transition behavior of aqueous solutions and can be used for the optimization of lyophilization and freezing of foods and biopharmaceutical formulations, among many other applications where freezing plays a crucial role. PMID:25482069

  3. Gamma irradiation of isocitric and citric acid in aqueous solution: Relevance in prebiotic chemistry

    SciTech Connect

    Negrón-Mendoza, A., E-mail: negron@nucleares.unam.mx; Ramos-Bernal, S.

    The radiation chemistry of hydroxy acids like citric and isocitric acids is rather scarce, even though they are crucial compounds in biological systems and for food irradiation. The aim of this work is to study the radiolytic behavior of these acids focused on the interconversion induced by radiation of citric and isocitric acid into other members of the Krebs cycle. The results showed that among the products formed were succinic, malonic, malic and other acids related to metabolic pathways, and these results are correlated with its possible role in chemical evolution processes.

  4. Importance of Unimolecular HO 2 Elimination in the Heterogeneous OH Reaction of Highly Oxygenated Tartaric Acid Aerosol

    DOE PAGES

    Cheng, Chiu Tung; Chan, Man Nin; Wilson, Kevin R.

    2016-07-09

    Oxygenated organic molecules are abundant in atmospheric aerosols and are transformed by oxidation reactions near the aerosol surface by gas-phase oxidants such as hydroxyl (OH) radicals. To gain better insights into how the structure of an organic molecule, particularly in the presence of hydroxyl groups, controls the heterogeneous reaction mechanisms of oxygenated organic compounds, this paper investigates the OH-radical initiated oxidation of aqueous tartaric acid (C 4H 6O 6) droplets using an aerosol flow tube reactor. The molecular composition of the aerosols before and after reaction is characterized by a soft atmospheric pressure ionization source (Direct Analysis in Real Time)more » coupled with a high-resolution mass spectrometer. The aerosol mass spectra reveal that four major reaction products are formed: a single C 4 functionalization product (C 4H 4O 6) and three C 3 fragmentation products (C 3H 4O 4, C 3H 2O 4, and C 3H 2O 5). The C 4 functionalization product does not appear to originate from peroxy radical self-reactions but instead forms via an α-hydroxylperoxy radical produced by a hydrogen atom abstraction by OH at the tertiary carbon site. The proximity of a hydroxyl group to peroxy group enhances the unimolecular HO 2 elimination from the α-hydroxylperoxy intermediate. This alcohol-to-ketone conversion yields 2-hydroxy-3-oxosuccinic acid (C 4H 4O 6), the major reaction product. While in general, C–C bond scission reactions are expected to dominate the chemistry of organic compounds with high average carbon oxidation states (OS C), our results show that molecular structure can play a larger role in the heterogeneous transformation of tartaric acid (OS C = 1.5). Finally, these results are also compared with two structurally related dicarboxylic acids (succinic acid and 2,3-dimethylsuccinic acid) to elucidate how the identity and location of functional groups (methyl and hydroxyl groups) alter heterogeneous reaction mechanisms.« less

  5. Effect of citric acid on setting reaction and tissue response to β-TCP granular cement.

    PubMed

    Fukuda, Naoyuki; Tsuru, Kanji; Mori, Yoshihide; Ishikawa, Kunio

    2017-02-24

    We recently reported that when an acidic calcium phosphate solution is mixed with β-tricalcium phosphate (β-TCP) granules, the resulting dicalcium phosphate dihydrate (DCPD) crystals form bridges between the β-TCP granules, creating a set interconnected porous structure in approximately 1 min. Although this self-setting β-TCP granular cement (β-TCPGC) is useful for clinical applications, the short setting time is a key drawback for handling. In this study, the setting time of β-TCPGC was adjusted with the addition of citric acid, which is a known inhibiter of DCPD crystal growth. As the concentration of citric acid in the acidic calcium phosphate solution increased, the amount of DCPD formation in the set β-TCPGC decreased, and the crystal morphology of DCPD became elongated. β-TCPGC prepared with various citric acid concentrations were used as grafting material in rat calvarial bone defects to evaluate bone regeneration in vivo. Four weeks after implantation, no inflammatory reaction and approximately 20% new bone formation were observed, regardless of the presence or absence of citric acid in the liquid phase of β-TCPGC. We concluded, therefore, that citric acid might be a useful retarder of β-TCPGC setting times.

  6. Novel neuroprotective and hepatoprotective effects of citric acid in acute malathion intoxication.

    PubMed

    Abdel-Salam, Omar M E; Youness, Eman R; Mohammed, Nadia A; Yassen, Noha N; Khadrawy, Yasser A; El-Toukhy, Safinaz Ebrahim; Sleem, Amany A

    2016-12-01

    To study the effect of citric acid given alone or combined with atropine on brain oxidative stress, neuronal injury, liver damage, and DNA damage of peripheral blood lymphocytes induced in the rat by acute malathion exposure. Rats were received intraperitoneal (i.p.) injection of malathion 150 mg/kg along with citric acid (200 or 400 mg/kg, orally), atropine (1 mg/kg, i.p.) or citric acid 200 mg/kg + atropine 1 mg/kg and euthanized 4 h later. Malathion resulted in increased lipid peroxidation (malondialdehyde) and nitric oxide concentrations accompanied with a decrease in brain reduced glutathione, glutathione peroxidase (GPx) activity, total antioxidant capacity (TAC) and glucose concentrations. Paraoxonase-1, acetylcholinesterase (AChE) and butyrylcholinesterase activities decreased in brain as well. Liver aspartate aminotransferase and alanine aminotransferase activities were raised. The comet assay showed increased DNA damage of peripheral blood lymphocytes. Histological damage and increased expression of inducible nitric oxide synthase (iNOS) were observed in brain and liver. Citric acid resulted in decreased brain lipid peroxidation and nitric oxide. Meanwhile, glutathione, GPx activity, TAC capacity and brain glucose level increased. Brain AChE increased but PON1 and butyrylcholinesterase activities decreased by citric acid. Liver enzymes, the percentage of damaged blood lymphocytes, histopathological alterations and iNOS expression in brain and liver was decreased by citric acid. Meanwhile, rats treated with atropine showed decreased brain MDA, nitrite but increased GPx activity, TAC, AChE and glucose. The drug also decreased DNA damage of peripheral blood lymphocytes, histopathological alterations and iNOS expression in brain and liver. The study demonstrates a beneficial effect for citric acid upon brain oxidative stress, neuronal injury, liver and DNA damage due to acute malathion exposure. Copyright © 2016 Hainan Medical University. Production

  7. Preparation and physico-chemical properties of hydrogels from carboxymethyl cassava starch crosslinked with citric acid

    NASA Astrophysics Data System (ADS)

    Boonkham, Sasikan; Sangseethong, Kunruedee; Chatakanon, Pathama; Niamnuy, Chalida; Nakasaki, Kiyohiko; Sriroth, Klanarong

    2014-06-01

    Recently, environmentally friendly hydrogels prepared from renewable bio-based resources have drawn significant attention from both industrial and academic sectors. In this study, chemically crosslinked hydrogels have been developed from cassava starch which is a bio-based polymer using a non-toxic citric acid as a crosslinking agent. Cassava starch was first modified by carboxymethylation to improve its water absorbency property. The carboxymethyl cassava starch (CMCS) obtained was then crosslinked with citric acid at different concentrations and reaction times. The gel fraction of hydrogels increased progressively with increasing citric acid concentration. Free swelling capacity of hydrogels in de-ionized water, saline solution and buffers at various pHs as well as absorption under load were investigated. The results revealed that swelling behavior and mechanical characteristic of hydrogels depended on the citric acid concentration used in reaction. Increasing citric acid concentration resulted in hydrogels with stronger network but lower swelling and absorption capacity. The cassava starch hydrogels developed were sensitive to ionic strength and pH of surrounding medium, showing much reduced swelling capacity in saline salt solution and acidic buffers.

  8. Roles of oxygen radicals and elastase in citric acid-induced airway constriction of guinea-pigs

    PubMed Central

    Lai, Y -L; Chiou, W -Y; Lu, F J; Chiang, L Y

    1999-01-01

    Antioxidants attenuate noncholinergic airway constriction. To further investigate the relationship between tachykinin-mediated airway constriction and oxygen radicals, we explored citric acid-induced bronchial constriction in 48 young Hartley strain guinea-pigs, divided into six groups: control; citric acid; hexa(sulphobutyl)fullerenes+citric acid; hexa(sulphobutyl)fullerenes+phosphoramidon+citric acid; dimethylthiourea (DMTU)+citric acid; and DMTU+phosphoramidon+citric acid. Hexa(sulphobutyl)fullerenes and DMTU are scavengers of oxygen radicals while phosphoramidon is an inhibitor of the major degradation enzyme for tachykinins. Animals were anaesthetized, paralyzed, and artificially ventilated. Each animal was given 50 breaths of 4 ml saline or citric acid aerosol. We measured dynamic respiratory compliance (Crs), forced expiratory volume in 0.1 (FEV0.1), and maximal expiratory flow at 30% total lung capacity (V[dot above]max30) to evaluate the degree of airway constriction. Citric acid, but not saline, aerosol inhalation caused marked decreases in Crs, FEV0.1 and V[dot above]max30, indicating marked airway constriction. This constriction was significantly attenuated by either hexa(sulphobutyl)fullerenes or by DMTU. In addition, phosphoramidon significantly reversed the attenuating action of hexa(sulphobutyl)fullerenes, but not that of DMTU. Citric acid aerosol inhalation caused increases in both lucigenin- and t-butyl hydroperoxide-initiated chemiluminescence counts, indicating citric acid-induced increase in oxygen radicals and decrease in antioxidants in bronchoalveolar lavage fluid. These alterations were significantly suppressed by either hexa(sulphobutyl)fullerenes or DMTU. An elastase inhibitor eglin-c also significantly attenuated citric acid-induced airway constriction, indicating the contributing role of elastase in this type of constriction. We conclude that both oxygen radicals and elastase play an important role in tachykinin-mediated, citric acid

  9. Inhibition of oxidative phosphorylation for enhancing citric acid production by Aspergillus niger.

    PubMed

    Wang, Lu; Zhang, Jianhua; Cao, Zhanglei; Wang, Yajun; Gao, Qiang; Zhang, Jian; Wang, Depei

    2015-01-16

    The spore germination rate and growth characteristics were compared between the citric acid high-yield strain Aspergillus niger CGMCC 5751 and A. niger ATCC 1015 in media containing antimycin A or DNP. We inferred that differences in citric acid yield might be due to differences in energy metabolism between these strains. To explore the impact of energy metabolism on citric acid production, the changes in intracellular ATP, NADH and NADH/NAD+ were measured at various fermentation stages. In addition, the effects of antimycin A or DNP on energy metabolism and citric acid production was investigated by CGMCC 5751. By comparing the spore germination rate and the extent of growth on PDA plates containing antimycin A or DNP, CGMCC 5751 was shown to be more sensitive to antimycin A than ATCC 1015. The substrate-level phosphorylation of CGMCC 5751 was greater than that of ATCC 1015 on PDA plates with DNP. DNP at tested concentrations had no apparent effect on the growth of CGMCC 5751. There were no apparent effects on the mycelial morphology, the growth of mycelial pellets or the dry cell mass when 0.2 mg L(-1) antimycin A or 0.1 mg L(-1) DNP was added to medium at the 24-h time point. The concentrations of intracellular ATP, NADH and NADH/NAD+ of CGMCC 5751 were notably lower than those of ATCC 1015 at several fermentation stages. Moreover, at 96 h of fermentation, the citric acid production of CGMCC 5751 reached up to 151.67 g L(-1) and 135.78 g L(-1) by adding 0.2 mg L(-1) antimycin A or 0.1 mg L(-1) DNP, respectively, at the 24-h time point of fermentation. Thus, the citric acid production of CGMCC 5751 was increased by 19.89% and 7.32%, respectively. The concentrations of intracellular ATP, NADH and NADH/NAD+ of the citric acid high-yield strain CGMCC 5751 were notably lower than those of ATCC 1015. The excessive ATP has a strong inhibitory effect on citric acid accumulation by A. niger. Increasing NADH oxidation and appropriately reducing the concentration of

  10. Quality changes and shelf-life extension of ready-to-eat fish patties by adding encapsulated citric acid.

    PubMed

    Bou, Ricard; Claret, Anna; Stamatakis, Antonios; Martínez, Brigitte; Guerrero, Luis

    2017-12-01

    Citric acid is commonly used as a flavoring and preservative in food and beverages. The effect of adding citric acid directly or encapsulated (each at 1 and 2 g kg -1 ) on the quality and shelf-life of ready-to-eat sea bass patties was evaluated during storage at 4 °C in vacuum skin packaging. Microbial growth and total basic volatile nitrogen were maintained at relatively low levels up to 8 weeks of storage. With respect to oxidative stability, the addition of encapsulated citric acid minimized secondary oxidation values more efficiently than its direct addition, regardless of the concentration. This is in agreement with the decreased fishy odor observed in those patties containing encapsulated citric acid. Accordingly, sensory analysis showed that the addition of encapsulated citric acid at 1 g kg -1 resulted in lower scores in fish aroma compared to that of the control. Sourness is dependent on the amount of citric acid added, regardless of the form (direct or encapsulated). The form of citric acid addition, rather than the amount of citric acid added, caused changes in texture. Therefore, the use of encapsulated citric acid represents a suitable strategy that is of great interest in the seafood industry. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  11. Citric Acid-Modified Fenton's Reaction for the Oxidation of Chlorinated Ethylenes in Soil Solution Systems

    SciTech Connect

    Seol, Yongkoo; Javandel, Iraj

    Fenton's reagent, a solution of hydrogen peroxide and ferrous iron catalyst, is used for an in-situ chemical oxidation of organic contaminants. Sulfuric acid is commonly used to create an acidic condition needed for catalytic oxidation. Fenton's reaction often involves pressure buildup and precipitation of reaction products, which can cause safety hazards and diminish efficiency. We selected citric acid, a food-grade substance, as an acidifying agent to evaluate its efficiencies for organic contaminant removal in Fenton's reaction, and examined the impacts of using citric acid on the unwanted reaction products. A series of batch and column experiments were performed with varyingmore » H{sub 2}O{sub 2} concentrations to decompose selected chlorinated ethylenes. Either dissolved iron from soil or iron sulfate salt was added to provide the iron catalyst in the batch tests. Batch experiments revealed that both citric and sulfuric acid systems achieved over 90% contaminant removal rates, and the presence of iron catalyst was essential for effective decontamination. Batch tests with citric acid showed no signs of pressure accumulation and solid precipitations, however the results suggested that an excessive usage of H{sub 2}O{sub 2} relative to iron catalysts (Fe{sup 2+}/H{sub 2}O{sub 2} < 1/330) would result in lowering the efficiency of contaminant removal by iron chelations in the citric acid system. Column tests confirmed that citric acid could provide suitable acidic conditions to achieve higher than 55% contaminant removal rates.« less

  12. Simultaneous saccharification and aerobic fermentation of high titer cellulosic citric acid by filamentous fungus Aspergillus niger.

    PubMed

    Hou, Weiliang; Bao, Jie

    2018-04-01

    Simultaneous saccharification and fermentation (SSF) is the most efficient operation in biorefining conversion, but aerobic SSF under high solids loading significantly faces the serious oxygen transfer limitation. This study took the first insight into an aerobic SSF by high oxygen demanding filamentous fungi in highly viscous lignocellulose hydrolysate. The results show that oxygen requirement in the aerobic SSF by Aspergillus niger was well satisfied for production of cellulosic citric acid. The record high citric acid titer of 136.3 g/L and the overall conversion yield of 74.9% of cellulose were obtained by the aerobic SSF. The advantage of SSF to the separate hydrolysis and fermentation (SHF) on citric acid fermentation was compared based on the rigorous Aspen Plus modeling. The techno-economic analysis indicates that the minimum citric acid selling price (MCSP) of $0.603 per kilogram by SSF was highly competitive with the commercial citric acid from starch feedstock. Copyright © 2018 Elsevier Ltd. All rights reserved.

  13. Metabolic interaction between urea cycle and citric acid cycle shunt: A guided approach.

    PubMed

    Pesi, Rossana; Balestri, Francesco; Ipata, Piero L

    2018-03-01

    This article is a guided pedagogical approach, devoted to postgraduate students specializing in biochemistry, aimed at presenting all single reactions and overall equations leading to the metabolic interaction between ureagenesis and citric acid cycle to be incorporated into a two-three lecture series about the interaction of urea cycle with other metabolic pathways. We emphasize that citrate synthetase, aconitase, and isocitrate dehydrogenase, three enzymes of the citric acid cycle are not involved, thus creating a shunt in citric acid cycle. In contrast, the glutamic-oxaloacetate transaminase, which does not belong to citric acid cycle, has a paramount importance in the metabolic interaction of the two cycles, because it generates aspartate, one of the two fuel molecules of urea cycle, and a-ketoglutarate, an intermediate of the citric acid cycle. Finally, students should appreciate that balancing equations for all atoms and charges is not only a stoichiometric task, but strongly facilitates the discussion of the physiological roles of metabolic pathways. Indeed, this exercise has been used in the classroom, to encourage a deeper level of understanding of an important biochemical issue. © 2017 by The International Union of Biochemistry and Molecular Biology, 46(2):182-185, 2018. © 2017 The International Union of Biochemistry and Molecular Biology.

  14. 27 CFR 24.182 - Use of acid to correct natural deficiencies.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... acid, fumaric acid, malic acid, lactic acid or tartaric acid, or a combination of two or more of these... citric acid for other fruit (including berries). (d) Other use of acid. A winemaker desiring to use an... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Use of acid to correct...

  15. 27 CFR 24.182 - Use of acid to correct natural deficiencies.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... acid, fumaric acid, malic acid, lactic acid or tartaric acid, or a combination of two or more of these... citric acid for other fruit (including berries). (d) Other use of acid. A winemaker desiring to use an... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Use of acid to correct...

  16. 27 CFR 24.182 - Use of acid to correct natural deficiencies.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... acid, fumaric acid, malic acid, lactic acid or tartaric acid, or a combination of two or more of these... citric acid for other fruit (including berries). (d) Other use of acid. A winemaker desiring to use an... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Use of acid to correct...

  17. 27 CFR 24.182 - Use of acid to correct natural deficiencies.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... acid, fumaric acid, malic acid, lactic acid or tartaric acid, or a combination of two or more of these... citric acid for other fruit (including berries). (d) Other use of acid. A winemaker desiring to use an... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Use of acid to correct...

  18. Effect of citric acid concentration and hydrolysis time on physicochemical properties of sweet potato starches.

    PubMed

    Surendra Babu, Ayenampudi; Parimalavalli, Ramanathan; Rudra, Shalini Gaur

    2015-09-01

    Physicochemical properties of citric acid treated sweet potato starches were investigated in the present study. Sweet potato starch was hydrolyzed using citric acid with different concentrations (1 and 5%) and time periods (1 and 11 h) at 45 °C and was denoted as citric acid treated starch (CTS1 to CTS4) based on their experimental conditions. The recovery yield of acid treated starches was above 85%. The CTS4 sample displayed the highest amylose (around 31%) and water holding capacity its melting temperature was 47.66 °C. The digestibility rate was slightly increased for 78.58% for the CTS3 and CTS4. The gel strength of acid modified starches ranged from 0.27 kg to 1.11 kg. RVA results of acid thinned starches confirmed a low viscosity profile. CTS3 starch illustrated lower enthalpy compared to all other modified starches. All starch samples exhibited a shear-thinning behavior. SEM analysis revealed that the extent of visible degradation was increased at higher hydrolysis time and acid concentration. The CTS3 satisfied the criteria required for starch to act as a fat mimetic. Overall results conveyed that the citric acid treatment of sweet potato starch with 5% acid concentration and 11h period was an ideal condition for the preparation of a fat replacer. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Differential effects of citric acid on cadmium uptake and accumulation between tall fescue and Kentucky bluegrass.

    PubMed

    Wang, ShuTing; Dong, Qin; Wang, ZhaoLong

    2017-11-01

    Organic acids play an important role in cadmium availability, uptake, translocation, and detoxification. A sand culture experiment was designed to investigate the effects of citric acid on Cd uptake, translocation, and accumulation in tall fescue and Kentucky bluegrass. The results showed that two grass species presented different Cd chemical forms, organic acid components and amount in roots. The dormant Cd accumulated in roots of tall fescue was the pectate- and protein- integrated form, which contributed by 84.85%. However, in Kentucky bluegrass, the pectate- and protein- integrated Cd was only contributed by 35.78%, and the higher proportion of Cd form was the water soluble Cd-organic acid complexes. In tall fescue, citric acid dramatically enhanced 2.8 fold of Cd uptake, 3 fold of root Cd accumulation, and 2.3 fold of shoot Cd accumulation. In Kentucky bluegrass, citric acid promoted Cd accumulation in roots, but significantly decreased Cd accumulation in shoots. These results suggested that the enhancements of citric acid on Cd uptake, translocation, and accumulation in tall fescue was associated with its promotion of organic acids and the water soluble Cd-organic acid complexes in roots. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Detection and formation scenario of citric acid, pyruvic acid, and other possible metabolism precursors in carbonaceous meteorites

    PubMed Central

    Cooper, George; Reed, Chris; Nguyen, Dang; Carter, Malika; Wang, Yi

    2011-01-01

    Carbonaceous meteorites deliver a variety of organic compounds to Earth that may have played a role in the origin and/or evolution of biochemical pathways. Some apparently ancient and critical metabolic processes require several compounds, some of which are relatively labile such as keto acids. Therefore, a prebiotic setting for any such individual process would have required either a continuous distant source for the entire suite of intact precursor molecules and/or an energetic and compact local synthesis, particularly of the more fragile members. To date, compounds such as pyruvic acid, oxaloacetic acid, citric acid, isocitric acid, and α-ketoglutaric acid (all members of the citric acid cycle) have not been identified in extraterrestrial sources or, as a group, as part of a “one pot” suite of compounds synthesized under plausibly prebiotic conditions. We have identified these compounds and others in carbonaceous meteorites and/or as low temperature (laboratory) reaction products of pyruvic acid. In meteorites, we observe many as part of three newly reported classes of compounds: keto acids (pyruvic acid and homologs), hydroxy tricarboxylic acids (citric acid and homologs), and tricarboxylic acids. Laboratory syntheses using 13C-labeled reactants demonstrate that one compound alone, pyruvic acid, can produce several (nonenzymatic) members of the citric acid cycle including oxaloacetic acid. The isotopic composition of some of the meteoritic keto acids points to interstellar or presolar origins, indicating that such compounds might also exist in other planetary systems. PMID:21825143

  1. Detection and formation scenario of citric acid, pyruvic acid, and other possible metabolism precursors in carbonaceous meteorites.

    PubMed

    Cooper, George; Reed, Chris; Nguyen, Dang; Carter, Malika; Wang, Yi

    2011-08-23

    Carbonaceous meteorites deliver a variety of organic compounds to Earth that may have played a role in the origin and/or evolution of biochemical pathways. Some apparently ancient and critical metabolic processes require several compounds, some of which are relatively labile such as keto acids. Therefore, a prebiotic setting for any such individual process would have required either a continuous distant source for the entire suite of intact precursor molecules and/or an energetic and compact local synthesis, particularly of the more fragile members. To date, compounds such as pyruvic acid, oxaloacetic acid, citric acid, isocitric acid, and α-ketoglutaric acid (all members of the citric acid cycle) have not been identified in extraterrestrial sources or, as a group, as part of a "one pot" suite of compounds synthesized under plausibly prebiotic conditions. We have identified these compounds and others in carbonaceous meteorites and/or as low temperature (laboratory) reaction products of pyruvic acid. In meteorites, we observe many as part of three newly reported classes of compounds: keto acids (pyruvic acid and homologs), hydroxy tricarboxylic acids (citric acid and homologs), and tricarboxylic acids. Laboratory syntheses using (13)C-labeled reactants demonstrate that one compound alone, pyruvic acid, can produce several (nonenzymatic) members of the citric acid cycle including oxaloacetic acid. The isotopic composition of some of the meteoritic keto acids points to interstellar or presolar origins, indicating that such compounds might also exist in other planetary systems.

  2. Citric acid production using immobilized conidia of Aspergillus niger TMB 2022

    SciTech Connect

    Tsay, S.S.; To, K.Y.

    1987-02-20

    Conidia of Aspergillus niger TMB 2022 were immobilized in calcium alginate for the production of citric acid. A 1-ml condidia suspension containing ca. 2.32 x 10/sup 8/ conidia were entrapped into sodium alginate solution in order to prepare 3% Ca-alginate (w/v) gel bead. Immobilized conidia were inoculated into productive medium containing 14% sucrose, 0.25% (NH/sub 4/)/sub 2/CO/sub 3/, 0.25% KH/sub 2/PO/sub 4/, and 0.025% MgSO/sub 4/.7H/sub 2/O with addition of 0.06 mg/l CuSO/sub 4/.5H/sub 2/O, 0.25 mg/l ZnCl/sub 2/, 1.3 mg/l FeCl/sub 3/.6H/sub 2/O, pH 3.8, and incubated at 35 degrees C for 13 days by surface culture to producemore » 61.53 g/l anhydrous citric acid. Under the same conditions with a batchwise culture, it was found that immobilized conidia could maintain a longer period for citric acid production (31 days): over 70 g/l anhydrous citric acid from runs No. 2-4, with the maximum yield for anhydrous citric acid reaching 77.02 g/l for run No. 2. In contrast, free conidia maintained a shorter acid-producing phase, circa 17 days; the maximum yield for anhydrous citric acid was 71.07 g/l for run No. 2 but dropped quickly as the run number increased. 14 references.« less

  3. Voltammetric determination of tartaric acid in wines by electrocatalytic oxidation on a cobalt(II)-phthalocyanine-modified electrode associated with multiway calibration.

    PubMed

    Lourenço, Anabel S; Nascimento, Raphael F; Silva, Amanda C; Ribeiro, Williame F; Araujo, Mario C U; Oliveira, Severino C B; Nascimento, Valberes B

    2018-05-30

    The electrocatalytic oxidation of tartaric acid on a carbon paste electrode modified with cobalt (II)-phthalocyanine was demonstrated and applied to the development of a highly sensitive, simple, fast and inexpensive voltammetric sensor to determine tartaric acid. The electrochemical behavior of the modified electrode was investigated by cyclic and square wave voltammetry, and the effect of experimental variables, such as dispersion and loading of cobalt (II)-phthalocyanine, together with optimum conditions for sensing the analyte by square wave voltammetry were assessed. In addition, the absence of a significant memory effect combined with the ease of electrode preparation led to the development of a sensitive and direct method to determine tartaric acid in wines. Interferences from other low molecular weight organic acids commonly present in wines were circumvented by using a multiway calibration technique, successfully obtaining the second order advantage by modeling voltammetric data with unfolded partial least square with residual bilinearization (U-PLS/RBL). A linear response range between 10 and 100 μmol L -1 (r = 0.9991), a relative prediction error of 4.55% and a recovery range from 96.41 to 102.43% were obtained. The proposed method is non-laborious, since it does not use sample pretreatment such as filtration, extraction, pre-concentration or cleanup procedures. Copyright © 2018 Elsevier B.V. All rights reserved.

  4. Effects of citric acid esterification on digestibility, structural and physicochemical properties of cassava starch.

    PubMed

    Mei, Ji-Qiang; Zhou, Da-Nian; Jin, Zheng-Yu; Xu, Xue-Ming; Chen, Han-Qing

    2015-11-15

    In this study, citric acid was used to react with cassava starch in order to compare the digestibility, structural and physicochemical properties of citrate starch samples. The results indicated that citric acid esterification treatment significantly increased the content of resistant starch (RS) in starch samples. The swelling power and solubility of citrate starch samples were lower than those of native starch. Compared with native starch, a new peak at 1724 cm(-1) was appeared in all citrate starch samples, and crystalline peaks of all starch citrates became much smaller or even disappeared. Differential scanning calorimetry results indicated that the endothermic peak of citrate starches gradually shrank or even disappeared. Moreover, the citrate starch gels exhibited better freeze-thaw stability. These results suggested that citric acid esterification induced structural changes in cassava starch significantly affected its digestibility and it could be a potential method for the preparation of RS with thermal stability. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. A Candida guilliermondii lysine hyperproducer capable of elevated citric acid production.

    PubMed

    West, Thomas P

    2016-05-01

    A mutant of the yeast Candida guilliermondii ATCC 9058 exhibiting elevated citric acid production was isolated based upon its ability to overproduce lysine. This method involved the use of a solid medium containing a combination of lysine analogues to identify a mutant that produced a several-fold higher lysine level compared to its parent strain using glucose or glycerol as a carbon source. The mutant strain was also capable of producing more than a fivefold higher citric acid level on glycerol as a carbon source compared to its parent strain. It was concluded that the screening of yeast lysine hyperproducer strains could provide a rapid approach to isolate yeast citric acid hyperproducer strains.

  6. Synergistic effect of tartaric acid with 2,6-diaminopyridine on the corrosion inhibition of mild steel in 0.5 M HCl

    PubMed Central

    Qiang, Yujie; Guo, Lei; Zhang, Shengtao; Li, Wenpo; Yu, Shanshan; Tan, Jianhong

    2016-01-01

    The inhibitive ability of 2,6-diaminopyridine, tartaric acid and their synergistic effect towards mild steel corrosion in 0.5 M HCl solution was evaluated at various concentrations using potentiodynamic polarization measurements, electrochemical impedance spectroscopy (EIS), and weight loss experiments. Corresponding surfaces of mild steel were examined by atomic force microscope (AFM), field emission scanning electron microscope (FE-SEM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS) analysis. The experimental results are in good agreement and reveal a favorable synergistic effect of 2,6-diaminopyridine with tartaric acid, which could protect mild steel from corrosion effectively. Besides, quantum chemical calculations and Monte Carlo simulation were used to clarify the inhibition mechanism of the synergistic effect. PMID:27628901

  7. A comparative study on glycerol metabolism to erythritol and citric acid in Yarrowia lipolytica yeast cells.

    PubMed

    Tomaszewska, Ludwika; Rakicka, Magdalena; Rymowicz, Waldemar; Rywińska, Anita

    2014-09-01

    Citric acid and erythritol biosynthesis from pure and crude glycerol by three acetate-negative mutants of Yarrowia lipolytica yeast was investigated in batch cultures in a wide pH range (3.0-6.5). Citric acid biosynthesis was the most effective at pH 5.0-5.5 in the case of Wratislavia 1.31 and Wratislavia AWG7. With a decreasing pH value, the direction of biosynthesis changed into erythritol synthesis accompanied by low production of citric acid. Pathways of glycerol conversion into erythritol and citric acid were investigated in Wratislavia K1 cells. Enzymatic activity was compared in cultures run at pH 3.0 and 4.5, that is, under conditions promoting the production of erythritol and citric acid, respectively. The effect of pH value (3.0 and 4.5) and NaCl presence on the extracellular production and intracellular accumulation of citric acid and erythritol was compared as well. Low pH and NaCl resulted in diminished activity of glycerol kinase, whereas such conditions stimulated the activity of glycerol-3-phosphate dehydrogenase. The presence of NaCl strongly influenced enzymes activity - the effective erythritol production was correlated with a high activity of transketolase and erythrose reductase. Therefore, presented results confirmed that transketolase and erythrose reductase are involved in the overproduction of erythritol in the cells of Y. lipolytica yeast. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  8. Effect of Ginger Extract and Citric Acid on the Tenderness of Duck Breast Muscles

    PubMed Central

    2015-01-01

    The objective of this study was to examine the effect of ginger extract (GE) combined with citric acid on the tenderness of duck breast muscles. Total six marinades were prepared with the combination of citric acid (0 and 0.3 M citric acid) and GE (0, 15, and 30%). Each marinade was sprayed on the surface of duck breasts (15 mL/100 g), and the samples were marinated for 72 h at 4℃. The pH and proteolytic activity of marinades were determined. After 72 h of marination, Warner Bratzler shear force (WBSF), myofibrillar fragmentation index (MFI), pH, cooking loss, moisture content, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and protein solubility were evaluated. There was no significant (p>0.05) difference in moisture content or cooking loss among all samples. However, GE marination resulted in a significant (p<0.05) decrease in WBSF but a significant (p<0.05) increase in pH and MFI. In addition, total protein and myofibrillar protein solubility of GE-marinated duck breast muscles in both WOC (without citric acid) and WC (with citric acid) conditions were significantly (p<0.05) increased compared to non-GE-marinated duck breast muscles. SDS-PAGE showed an increase of protein degradation (MHC and actin) in WC condition compared to WOC condition. There was a marked actin reduction in GE-treated samples in WC. The tenderization effect of GE combined with citric acid may be attributed to various mechanisms such as increased MFI and myofibrillar protein solubility. PMID:26877631

  9. Modification of rat detrusor muscle contraction by ascorbic acid and citric acid involving enhanced neurotransmitter release and Ca2+ influx.

    PubMed

    Dasgupta, Jaydip; Elliott, Ruth A; Tincello, Douglas G

    2009-01-01

    Consumption of carbonated soft drinks is independently associated with the development of overactive bladder (OR 1.41, 95% Cl 1.02-1.95). We have shown previously that artificial sweeteners, present in carbonated soft drinks, enhanced detrusor muscle contraction. Other constituents of soft drinks are preservatives and antioxidants, we evaluated the effects of two of these, ascorbic acid and citric acid, on the contractile response of isolated rat bladder muscle strips. Detrusor muscle strips were suspended in a perfusion organ bath. We determined the effect of ascorbic acid and citric acid on the contractile responses to electrical field stimulation (EFS) in the absence and presence of atropine, carbachol, alpha, beta methylene ATP, potassium and calcium. Ascorbic acid and citric acid (10(-7) M to 10(-3) M) enhanced the contractile response to 10 Hz EFS compared to control (P < 0.01). The frequency and amplitude of spontaneous bladder contractions were enhanced in the presence of ascorbic acid and citric acid by 14%, 21%, 21%, and 11% respectively. Ascorbic acid 10(-4) M significantly increased the atropine resistant response to EFS 5 Hz by 37% (P < 0.01) and inhibited contraction in response to carbachol 10(-4) M by 24%, (P < 0.05). Both ascorbic acid 10(-4) M and citric acid 10(-5) M significantly enhanced maximum contractile responses to alpha, beta methylene ATP, KCI and calcium compared to control. Ascorbic acid and citric acid augmented bladder muscle contraction possibly by enhanced Ca(2+) influx. Presynaptic neurotransmitter release was enhanced by ascorbic acid. Carbonated beverages containing preservatives may aggravate symptoms of OAB. (c) 2009 Wiley-Liss, Inc.

  10. The Effect of Citric Acid on the Oxidation of Organic Contaminants by Fenton's Reagent

    NASA Astrophysics Data System (ADS)

    Seol, Y.; Javandel, I.; Lee, G.

    2003-12-01

    Combined with acids and iron catalysts, hydrogen peroxide (H2O2) as Fenton's reagent is proven to be effective in oxidizing halogenated volatile organic compounds (VOCs). The Fenton's reagent, traditionally used for waste water treatment technique, has been applied to the remediation of contaminated soil systems and numerous investigators have found intrinsic iron salts are effective source of iron catalyst for the reaction. Citric acid, which is naturally occurring nutrients to microorganisms and less destructive to soil chemical properties, is selected for an acidifying agent to create acidic soil condition. However, citric acid has been considered as a reaction inhibitant because it sequesters ferric iron from Fenton's catalytic cycle by forming strong chelates with iron. This paper presents the feasibility of using citric acid as an acidifying agent of soil matrix for the Fenton-like oxidation. Series of batch tests were performed to test disappearance of VOCs in various aqueous systems with two acidifying agents (citric acid or sulfuric acid) and three iron sources (iron sulfate, water soluble soil iron, or soil matrix). Batch results show that soluble iron is essential for near complete disappearance of VOCs and that citric acid performs similarly to sulfuric acid at low H2O2 dosage (< 1 wt%). The test soil provided water-soluble soil iron but also contained scavengers of the oxidizing agents, resulting in limited removals of VOCs. Column tests confirmed the results of the batch tests, suggesting citric acid is also as effective as sulfuric acid in providing acidic environment for the Fenton-like oxidation. The batch experiments also reveal that higher doses of H2O2 lower the degree of VOC removals in citric acid systems. Potential explanations for this declining include that excessive presence of H2O2 expedites the oxidation of ferrous to ferric iron, which then forms a strong complex with citrate, leading to the sequestration of the iron from the Fenton

  11. Growth, structural, optical, thermal and dielectric properties of lanthanum chloride—thiourea—L tartaric acid coordinated complex

    NASA Astrophysics Data System (ADS)

    Slathia, Goldy; Bamzai, K. K.

    2017-11-01

    Lanthanum chloride—thiourea—l tartaric acid coordinated complex was grown in the form of single crystal by slow evaporation of supersaturated solutions at room temperature. This coordinated complex crystallizes in orthorhombic crystal system having space group P nma. The crystallinity and purity was tested by powder x-ray diffraction. Fourier transform infra red and Raman spectroscopy analysis provide the evidences on structure and mode of coordination. The scanning electron microscopy (SEM) analysis shows the morphology evolution as brought by the increase in composition of lanthanum chloride. The band transitions due to C=O and C=S chromophores remain active in grown complexes and are recorded in the UV-vis optical spectrum. The thermal effects such as dehydration, melting and decomposition were observed by the thermogravimetric and differential thermo analytical (TGA/DTA) analysis. Electrical properties were studied by dielectric analysis in frequency range 100-30 MHz at various temperatures. Increase in values of dielectric constant was observed with change in lanthanum concentration in the coordinated complex.

  12. Crystallization Caught in the Act with Terahertz Spectroscopy: Non-Classical Pathway for l-(+)-Tartaric Acid.

    PubMed

    Soltani, Amin; Gebauer, Denis; Duschek, Lennart; Fischer, Bernd M; Cölfen, Helmut; Koch, Martin

    2017-10-12

    Crystal formation is a highly debated problem. This report shows that the crystallization of l-(+)-tartaric acid from water follows a non-classical path involving intermediate hydrated states. Analytical ultracentrifugation indicates solution clusters of the initial stages aggregate to form an early intermediate. Terahertz spectroscopy performed during water evaporation highlights a transient increase in the absorption during nucleation; this indicates the recurrence of water molecules that are expelled from the intermediate phase. Besides, a transient resonance at 750 GHz, which can be assigned to a natural vibration of large hydrated aggregates, vanishes after the final crystal has formed. Furthermore, THz data reveal the vibration of nanosized clusters in the dilute solution indicated by analytical ultracentrifugation. Infrared spectroscopy and wide-angle X-ray scattering highlight that the intermediate is not a crystalline hydrate. These results demonstrate that nanoscopic intermediate units assemble to form the first solvent-free crystalline nuclei upon dehydration. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Functionalized polycarbonate derived from tartaric acid: enzymatic ring-opening polymerization of a seven-membered cyclic carbonate.

    PubMed

    Wu, Ruizhi; Al-Azemi, Talal F; Bisht, Kirpal S

    2008-10-01

    Enantiomerically pure functional polycarbonate was synthesized from a novel seven-membered cyclic carbonate monomer derived from naturally occurring L-tartaric acid. The monomer was synthesized in three steps and screened for polymerization with four commercially available lipases from different sources at 80 degrees C, in bulk. The ring-opening polymerization (ROP) was affected by the source of the enzyme; the highest number-average molecular weight, M(n) = 15500 g/mol (PDI = 1.7; [alpha]D(20) = +77.8, T(m) = 58.8 degrees C) optically active polycarbonate was obtained with lipase Novozyme-435. The relationship between monomer conversion, reaction time, molecular weight, and molecular weight distribution were investigated for Novozyme-435 catalyzed ROP. Deprotection of the ketal groups was achieved with minimal polymer chain cleavage (M(n) = 10000 g/mol, PDI = 2.0) and resulted in optically pure polycarbonate ([alpha]D(20) = +56) bearing hydroxy functional groups. Deprotected poly(ITC) shows T(m) of 60.2 degrees C and DeltaH(f) = 69.56 J/g and similar to that of the poly(ITC), a glass transition temperature was not found. The availability of the pendant hydroxyl group is expected to enhance the biodegradability of the polymer and serves in a variety of potential biomedical applications such as polymeric drug delivery systems.

  14. Facile fabrication of self-assembled polyaniline nanotubes doped with D-tartaric acid for high-performance supercapacitors

    NASA Astrophysics Data System (ADS)

    Mu, Jingjing; Ma, Guofu; Peng, Hui; Li, Jiajia; Sun, Kanjun; Lei, Ziqiang

    2013-11-01

    Polyaniline (PANI) nanotubes with outstanding electrochemical properties have been successfully synthesized via a simple chemical template-free method in the presence of D-tartaric acid (D-TA) as the dopant, and ammonium persulfate ((NH4)2S2O8) as the oxidant. The morphologies and structures of PANI-(D-TA) with different [D-TA]/[aniline] molar ratios are characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) and X-ray diffraction (XRD). To assess the electrochemical properties of PANI-(D-TA) materials, cyclic voltammetry (CV) and galvanostatic charging-discharging measurements are performed. The PANI-(D-TA) nanotubes electrode, with [D-TA]/[aniline] molar ratio of 1:1, exhibits larger specific capacitance (as high as 625 F g-1 at 1 A g-1) and higher capacitance retention (77% of its initial capacitance after 500 cycles) in 1 M H2SO4 aqueous solution. The remarkable electrochemical characteristics of PANI-(D-TA) are mainly attributed to their unique nanotubular structures, which provide a high electrode/electrolyte contact area and short ions diffusion path. These novel PANI-(D-TA) nanotubes will be promising electrode materials for high-performance supercapacitors.

  15. Structures of chloralide, ?-lactic acid chloralide, malic acid chloralide and citric acid chloralide

    NASA Astrophysics Data System (ADS)

    Koh, L. L.; Huang, H. H.; Chia, L. H. L.; Liang, E. P.

    1995-06-01

    The crystal and molecular structures of chloralide ( 1), D-lactic acid chloralide ( 2), malic acid chloralide ( 3) and citric acid chloralide ( 4) have been determined by X-ray diffraction methods. Compound 1 crystallizes in the monoclinic space group, {P2 1}/{c}, a = 6.201(2), b = 17.11(2), c = 10.357(6) Å, β = 95.21(4)°, Z = 4; compound 2 in the monoclinic space group P2 1, a = 7.600(4), b = 5.902(4), c = 9.743(6) Å, β = 99.20(5), Z = 2; compound 3 in the monoclinic space group {P2 1}/{c}, a = 16.500(6), b = 5.819(3), c = 10.120(4) Å, β = 91.41(3), Z = 4; compound 4 in the monoclinic space group {P2 1}/{c}, a = 12.041(3), b = 6.1190(10), c = 17.259(4) Å, β = 101.85(2), Z = 4. The five-membered ring systems of all the compounds are slightly twisted out-of-plane, that of compound 4 being the most puckered. The CCl 3 group is trans to the second CCl 3 group in 1, to the CH 3 group in 2 and to the CH 2COOH group in 3. The two CH 2COOH groups in 4 are disposed axially with respect to the ring. Dipole moment and Kerr constant data for D-lactic acid chloralide suggest a structure in solution which is consistent with the X-ray results. The IR spectra of 2, 3 and 4 are discussed in relation to the structures of these compounds.

  16. 78 FR 54625 - Citric Acid and Certain Citrate Salts From the People's Republic of China: Notice of Partial...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-05

    ... DEPARTMENT OF COMMERCE International Trade Administration [C-570-938] Citric Acid and Certain Citrate Salts From the People's Republic of China: Notice of Partial Rescission of Countervailing Duty... of the countervailing duty (CVD) order on citric acid and certain citrate salts from the People's...

  17. 76 FR 2648 - Citric Acid and Certain Citrate Salts From People's Republic of China: Extension of Time Limit...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-14

    ... DEPARTMENT OF COMMERCE International Trade Administration [C-570-938] Citric Acid and Certain Citrate Salts From People's Republic of China: Extension of Time Limit for the Preliminary Results of the... duty order on citric acid and certain citrate salts from the People's Republic of China, covering the...

  18. The Cardioprotective Effects of Citric Acid and L-Malic Acid on Myocardial Ischemia/Reperfusion Injury

    PubMed Central

    Tang, Xilan; Liu, Jianxun; Dong, Wei; Li, Peng; Li, Lei; Lin, Chengren; Zheng, Yongqiu; Hou, Jincai; Li, Dan

    2013-01-01

    Organic acids in Chinese herbs, the long-neglected components, have been reported to possess antioxidant, anti-inflammatory, and antiplatelet aggregation activities; thus they may have potentially protective effect on ischemic heart disease. Therefore, this study aims to investigate the protective effects of two organic acids, that is, citric acid and L-malic acid, which are the main components of Fructus Choerospondiatis, on myocardial ischemia/reperfusion injury and the underlying mechanisms. In in vivo rat model of myocardial ischemia/reperfusion injury, we found that treatments with citric acid and L-malic acid significantly reduced myocardial infarct size, serum levels of TNF-α, and platelet aggregation. In vitro experiments revealed that both citric acid and L-malic acid significantly reduced LDH release, decreased apoptotic rate, downregulated the expression of cleaved caspase-3, and upregulated the expression of phosphorylated Akt in primary neonatal rat cardiomyocytes subjected to hypoxia/reoxygenation injury. These results suggest that both citric acid and L-malic acid have protective effects on myocardial ischemia/reperfusion injury; the underlying mechanism may be related to their anti-inflammatory, antiplatelet aggregation and direct cardiomyocyte protective effects. These results also demonstrate that organic acids, besides flavonoids, may also be the major active ingredient of Fructus Choerospondiatis responsible for its cardioprotective effects and should be attached great importance in the therapy of ischemic heart disease. PMID:23737849

  19. Selective Precipitation of Thorium lodate from a Tartaric Acid-Hydrogen Peroxide Medium Application to Rapid Spectrophotometric Determination of Thorium in Silicate Rocks and in Ores

    USGS Publications Warehouse

    Grimaldi, F.S.

    1957-01-01

    This paper presents a selective iodate separation of thorium from nitric acid medium containing d-tartaric acid and hydrogen peroxide. The catalytic decomposition of hydrogen peroxide is prevented by the use of 8quinolinol. A few micrograms of thorium are separated sufficiently clean from 30 mg. of such oxides as cerium, zirconium, titanium, niobium, tantalum, scandium, or iron with one iodate precipitation to allow an accurate determination of thorium with the thoronmesotartaric acid spectrophotometric method. The method is successful for the determination of 0.001% or more of thorium dioxide in silicate rocks and for 0.01% or more in black sand, monazite, thorite, thorianite, eschynite, euxenite, and zircon.

  20. Exogenous Application of Citric Acid Ameliorates the Adverse Effect of Heat Stress in Tall Fescue (Lolium arundinaceum)

    PubMed Central

    Hu, Longxing; Zhang, Zhifei; Xiang, Zuoxiang; Yang, Zhijian

    2016-01-01

    Citric acid may be involved in plant response to high temperature. The objective of this study was to investigate whether exogenous citric acid could improve heat tolerance in a cool-season turfgrass species, tall fescue (Lolium arundinaceum), and to determine the physiological mechanisms of citric acid effects on heat stress tolerance. The grasses were subjected to four citric acid levels (0, 0.2, 2, and 20 mM) and two temperature levels (25/20 and 35/30 ± 0.5°C, day/night) treatments in growth chambers. Heat stress increased an electrolyte leakage (EL) and malonaldehyde (MDA) content, while reduced plant growth, chlorophyll (Chl) content, photochemical efficiency (Fv/Fm), root activity and antioxidant enzyme activities (superoxide dismutase, SOD; catalase, CAT; peroxidase, POD). External citric acid alleviated the detrimental effects of heat stress on tall fescue, which was evidenced by decreased EL and MDA content, and improved plant growth under stress conditions. Additionally, the reduction in Chl content, Fv/Fm, SOD, POD, CAT and root activity were ameliorated in citric acid treated plants under heat stressed conditions. High temperature induced the expression of heat shock protein (HSP) genes, which exhibited greater expression levels after citric acid treatment under heat stress. These results suggest that exogenous citric acid application may alleviate growth and physiological damage caused by high temperature. In addition, the exogenously applied citric acid might be responsible for maintaining membrane stability, root activity, and activation of antioxidant response and HSP genes which could contribute to the protective roles of citric acid in tall fescue responses to heat stress. PMID:26925085

  1. Optimization of date syrup for enhancement of the production of citric acid using immobilized cells of Aspergillus niger

    PubMed Central

    Mostafa, Yasser S.; Alamri, Saad A.

    2012-01-01

    Date syrup as an economical source of carbohydrates and immobilized Aspergillus niger J4, which was entrapped in calcium alginate pellets, were employed for enhancing the production of citric acid. Maximum production was achieved by pre-treating date syrup with 1.5% tricalcium phosphate to remove heavy metals. The production of citric acid using a pretreated medium was 38.87% higher than an untreated one that consumed sugar. The appropriate presence of nitrogen, phosphate and magnesium appeared to be important in order for citric acid to accumulate. The production of citric acid and the consumed sugar was higher when using 0.1% ammonium nitrate as the best source of nitrogen. The production of citric acid increased significantly when 0.1 g/l of KH2PO4 was added to the medium of date syrup. The addition of magnesium sulfate at the rate of 0.20 g/l had a stimulating effect on the production of citric acid. Maximum production of citric acid was obtained when calcium chloride was absent. One of the most important benefits of immobilized cells is their ability and stability to produce citric acid under a repeated batch culture. Over four repeated batches, the production of citric acid production was maintained for 24 days when each cycle continued for 144 h. The results obtained in the repeated batch cultivation using date syrup confirmed that date syrup could be used as a medium for the industrial production of citric acid. PMID:23961184

  2. Metabolic Interaction between Urea Cycle and Citric Acid Cycle Shunt: A Guided Approach

    ERIC Educational Resources Information Center

    Pesi, Rossana; Balestri, Francesco; Ipata, Piero L.

    2018-01-01

    This article is a guided pedagogical approach, devoted to postgraduate students specializing in biochemistry, aimed at presenting all single reactions and overall equations leading to the metabolic interaction between ureagenesis and citric acid cycle to be incorporated into a two-three lecture series about the interaction of urea cycle with other…

  3. Experimental Investigation and Analysis of Mercerized and Citric Acid Surface Treated Bamboo Fiber Reinforced Composite

    NASA Astrophysics Data System (ADS)

    De, Jyotiraman; Baxi, R. N., Dr.

    2017-08-01

    Mercerization or NaOH fiber surface treatment is one of the most popular surface treatment processes to make the natural fibers such as bamboo fibers compatible for use as reinforcing material in composites. But NaOH being a chemical is hazardous and polluting to the nature. This paper explores the possibility of use of naturally derived citric acid for bamboo fiber surface treatment and its comparison with NaOH treated Bamboo Fiber Composites. Untreated, 2.5 wt% NaOH treated and 5 wt% citric acid treated Bamboo Fiber Composites with 5 wt% fiber content were developed by Hand Lay process. Bamboo mats made of bamboo slivers were used as reinforcing material. Mechanical and physical characterization was done to compare the effects of NaOH and citric acid bamboo fiber surface treatment on mechanical and physical properties of Bamboo Fiber Composite. The experiment data reveals that the tensile and flexural strength was found to be highest for citric acid and NaOH treated Bamboo Fiber Composite respectively. Water absorption tendency was found more than the NaOH treated Bamboo Fiber Composites. SEM micrographs used to analyze the morphology of fracture surface of tensile test specimens confirm improvement in fiber-matrix interface bonding due to surface treatment of bamboo fibers.

  4. Simultaneous Removal of Lindane, Lead and Cadmium from Soils by Rhamnolipids Combined with Citric Acid.

    PubMed

    Wan, Jinzhong; Meng, Die; Long, Tao; Ying, Rongrong; Ye, Mao; Zhang, Shengtian; Li, Qun; Zhou, Yan; Lin, Yusuo

    2015-01-01

    This study investigated the performance of rhamnolipids-citric acid mixed agents in simultaneous desorption of lindane and heavy metals from soils. The capacity of the mixed agents to solubilize lindane, lead and cadmium in aqueous solution was also explored. The results showed that the presence of citric acid greatly enhanced the solubilization of lindane and cadmium by rhamnolipids. A combined effect of the mixed agents on lindane and heavy metals removal from soils was observed. The maximum desorption ratios for lindane, cadmium and lead were 85.4%, 76.4% and 28.1%, respectively, for the mixed agents containing 1% rhamnolipidsand 0.1 mol/L citric acid. The results also suggest that the removal efficiencies of lead and cadmium were strongly related to their speciations in soils, and metals in the exchangeable and carbonate forms were easier to be removed. Our study suggests that the combining use of rhamnolipids and citric acid is a promising alternative to simultaneously remove organochlorine pesticides and heavy metals from soils.

  5. Electromigration of Mn, Fe, Cu and Zn with citric acid in contaminated clay.

    PubMed

    Pazos, M; Gouveia, S; Sanroman, M A; Cameselle, C

    2008-07-01

    Metal reactivity, speciation and solubility have an important influence in its transportation through a porous matrix by electrokinetics and, therefore, they dramatically affect the removal efficiency. This work deals with the effect of solubility and transport competition among several metals (Mn, Fe, Cu and Zn) during their transport through polluted clay. The unenhancement electrokinetic treatment results in a limited removal of the tested metals because they were retained into the kaolinite sample by the penetration of the alkaline front. Metals showed a removal degree in accordance with the solubility of the corresponding hydroxide and its formation pH. In 7 days of treatment, the removal results were: 75.6% of Mn; 68.5% of Zn, 40.6% of Cu and 14.8% of Fe. In order to avoid the negative effects of the basic front generated at the cathode, two different techniques were proposed and tested: the addition of citric acid as complexing agent to the polluted kaolinite sample and the use of citric acid to control de pH on the cathode chamber. Both techniques are based on the capability of citric acid to act as a complexing and neutralizing agent. Almost complete removal of Mn, Cu and Zn was achieved when citric acid was used (as neutralizing or complexing agent). But Fe only reached 33% of removal because it formed a negatively charged complex with citrate that retarded its transportation to the cathode.

  6. Simultaneous Removal of Lindane, Lead and Cadmium from Soils by Rhamnolipids Combined with Citric Acid

    PubMed Central

    Long, Tao; Ying, Rongrong; Ye, Mao; Zhang, Shengtian; Li, Qun; Zhou, Yan; Lin, Yusuo

    2015-01-01

    This study investigated the performance of rhamnolipids-citric acid mixed agents in simultaneous desorption of lindane and heavy metals from soils. The capacity of the mixed agents to solubilize lindane, lead and cadmium in aqueous solution was also explored. The results showed that the presence of citric acid greatly enhanced the solubilization of lindane and cadmium by rhamnolipids. A combined effect of the mixed agents on lindane and heavy metals removal from soils was observed. The maximum desorption ratios for lindane, cadmium and lead were 85.4%, 76.4% and 28.1%, respectively, for the mixed agents containing 1% rhamnolipidsand 0.1 mol/L citric acid. The results also suggest that the removal efficiencies of lead and cadmium were strongly related to their speciations in soils, and metals in the exchangeable and carbonate forms were easier to be removed. Our study suggests that the combining use of rhamnolipids and citric acid is a promising alternative to simultaneously remove organochlorine pesticides and heavy metals from soils. PMID:26087302

  7. Leaching of metals from large pieces of printed circuit boards using citric acid and hydrogen peroxide.

    PubMed

    Jadhav, Umesh; Su, C; Hocheng, Hong

    2016-12-01

    In the present study, the leaching of metals from large pieces of computer printed circuit boards (CPCBs) was studied. A combination of citric acid (0.5 M) and 1.76 M hydrogen peroxide (H 2 O 2 ) was used to leach the metals from CPCB piece. The influence of system variables such as H 2 O 2 concentration, concentration of citric acid, shaking speed, and temperature on the metal leaching process was investigated. The complete metal leaching was achieved in 4 h from a 4 × 4 cm CPCB piece. The presence of citric acid and H 2 O 2 together in the leaching solution is essential for complete metal leaching. The optimum addition amount of H 2 O 2 was 5.83 %. The citric acid concentration and shaking speed had an insignificant effect on the leaching of metals. The increase in the temperature above 30 °C showed a drastic effect on metal leaching process.

  8. Experimental design data for the biosynthesis of citric acid using Central Composite Design method.

    PubMed

    Kola, Anand Kishore; Mekala, Mallaiah; Goli, Venkat Reddy

    2017-06-01

    In the present investigation, we report that statistical design and optimization of significant variables for the microbial production of citric acid from sucrose in presence of filamentous fungi A. niger NCIM 705. Various combinations of experiments were designed with Central Composite Design (CCD) of Response Surface Methodology (RSM) for the production of citric acid as a function of six variables. The variables are; initial sucrose concentration, initial pH of medium, fermentation temperature, incubation time, stirrer rotational speed, and oxygen flow rate. From experimental data, a statistical model for this process has been developed. The optimum conditions reported in the present article are initial concentration of sucrose of 163.6 g/L, initial pH of medium 5.26, stirrer rotational speed of 247.78 rpm, incubation time of 8.18 days, fermentation temperature of 30.06 °C and flow rate of oxygen of 1.35 lpm. Under optimum conditions the predicted maximum citric acid is 86.42 g/L. The experimental validation carried out under the optimal values and reported citric acid to be 82.0 g/L. The model is able to represent the experimental data and the agreement between the model and experimental data is good.

  9. Effectiveness of incorporating citric acid in cassava starch edible coatings to preserve quality of Martha tomatoes

    NASA Astrophysics Data System (ADS)

    Ambarsari, I.; Oktaningrum, G. N.; Endrasari, R.

    2018-01-01

    Tomato as an agricultural product is extremely perishable. Coatings of tomatoes with edible starch extend quality and storage life of the fruits. Incorporation of citric acid as antimicrobial agent in the edible starch coatings is expected to preserve the quality of tomatoes during storage. The aim of this study was to verify the effectiveness of citric acid incorporated in cassava starch coating to preserve quality of tomatoes. The edible coatings formula consisted of cassava starch solutions (1; 2; 3%), citric acid (0.5; 1.0%) and glycerol (10%). Tomatoes were dipped to the coating solution for 10 seconds, then air-dried and stored at room temperature during 18 days. All the treatments were carried out in triplicates. Experimental data were analyzed using One Way ANOVA. The results showed that coating treatments did not affect the weight loss, moisture content, color characteristic, carotene and vitamin C content on Martha tomatoes. The low concentration of starch coating on Martha tomatoes are indicated to be the reason why there was no significant difference between coated and coated tomatoes for some parameters. However, incorporating citric acid in cassava starch-based coatings could prevent tomato fruits from firmness reduction and spoilage during storage.

  10. Properties of polyvinyl alcohol/xylan composite films with citric acid.

    PubMed

    Wang, Shuaiyang; Ren, Junli; Li, Weiying; Sun, Runcang; Liu, Shijie

    2014-03-15

    Composite films of xylan and polyvinyl alcohol were produced with citric acid as a new plasticizer or a cross-linking agent. The effects of citric acid content and polyvinyl alcohol/xylan weight ratio on the mechanical properties, thermal stability, solubility, degree of swelling and water vapor permeability of the composite films were investigated. The intermolecular interactions and morphology of composite films were characterized by FTIR spectroscopy and SEM. The results indicated that polyvinyl alcohol/xylan composite films had good compatibility. With an increase in citric acid content from 10% to 50%, the tensile strength reduced from 35.1 to 11.6 MPa. However, the elongation at break increased sharply from 15.1% to 249.5%. The values of water vapor permeability ranged from 2.35 to 2.95 × 10(-7)g/(mm(2)h). Interactions between xylan and polyvinyl alcohol in the presence of citric acid become stronger, which were caused by hydrogen bond and ester bond formation among the components during film forming. Copyright © 2013. Published by Elsevier Ltd.

  11. Establishment and assessment of an integrated citric acid-methane production process.

    PubMed

    Xu, Jian; Chen, Yang-Qiu; Zhang, Hong-Jian; Bao, Jia-Wei; Tang, Lei; Wang, Ke; Zhang, Jian-Hua; Chen, Xu-Sheng; Mao, Zhong-Gui

    2015-01-01

    To solve the problem of extraction wastewater in citric acid industrial production, an improved integrated citric acid-methane production process was established in this study. Extraction wastewater was treated by anaerobic digestion and then the anaerobic digestion effluent (ADE) was stripped by air to remove ammonia. Followed by solid-liquid separation to remove metal ion precipitation, the supernatant was recycled for the next batch of citric acid fermentation, thus eliminating wastewater discharge and reducing water consumption. 130U/g glucoamylase was added to medium after inoculation and the recycling process performed for 10 batches. Fermentation time decreased by 20% in recycling and the average citric acid production (2nd-10th) was 145.9±3.4g/L, only 2.5% lower than that with tap water (149.6g/L). The average methane production was 292.3±25.1mL/g CODremoved and stable in operation. Excessive Na(+) concentration in ADE was confirmed to be the major challenge for the proposed process. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Modification of wheat gluten with citric acid to produce superabsorbent materials

    USDA-ARS?s Scientific Manuscript database

    Wheat gluten was reacted with citric acid to produce natural superabsorbent materials able to absorb up to 78 times its weight in water. The properties of the modified gluten samples were characterized using Fourier Transform Infra-red (FTIR) spectroscopy, thermogravimetric analysis, and water uptak...

  13. 78 FR 34648 - Citric Acid and Certain Citrate Salts: Preliminary Results of Countervailing Duty Administrative...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-10

    ... Citrate Salts: Preliminary Results of Countervailing Duty Administrative Review; 2011 AGENCY: Import... December 31, 2011. These preliminary results cover RZBC Group Shareholding Co., Ltd., RZBC Co., Ltd., RZBC... Memorandum for the Preliminary Results of the Countervailing Duty Administrative Review: Citric Acid and...

  14. Development of calcium phosphate cement using chitosan and citric acid for bone substitute materials.

    PubMed

    Yokoyama, Atsuro; Yamamoto, Satoru; Kawasaki, Takao; Kohgo, Takao; Nakasu, Masanori

    2002-02-01

    We developed a calcium phosphate cement that could be molded into any desired shape due to its chewing-gum-like consistency after mixing. The powder component of the cement consists of alpha-tricalcium phosphate and tetracalcium phosphate, which were made by decomposition of hydroxyapatite ceramic blocks. The liquid component consists of citric acid, chitosan and glucose solution. In this study, we used 20% citric acid (group 20) and 45% citric acid (group 45). The mechanical properties and biocompatibility of this new cement were investigated. The setting times of cements were 5.5 min, in group 20 and 6.4 min, in group 45. When incubated in physiological saline, the cements were transformed to hydroxyapatite at 3, and 6 weeks, the compressive strengths were 15.6 and 20.7 MPa, in group 45 and group 20, respectively. The inflammatory response around the cement implanted on the bone and in the subcutaneous tissue in rats was more prominent in group 45 than in group 20 at 1 week after surgery. After 4 weeks, the inflammation disappeared and the cement had bound to bone in both groups. These results indicate that this new calcium phosphate cement is a suitable bone substitute material and that the concentration of citric acid in the liquid component affects its mechanical properties and biocompatibility.

  15. Analysis of Citric Acid in Beverages: Use of an Indicator Displacement Assay

    ERIC Educational Resources Information Center

    Umali, Alona P.; Anslyn, Eric V.; Wright, Aaron T.; Blieden, Clifford R.; Smith, Carolyne K.; Tian, Tian; Truong, Jennifer A.; Crumm, Caitlin E.; Garcia, Jorge E.; Lee, Soal; Mosier, Meredith; Nguyen, Chester P.

    2010-01-01

    The use of an indicator displacement assay permits the visualization of binding events between host and guest molecules. An undergraduate laboratory experiment is described to demonstrate the technique in the determination of citric acid content in commercially available beverages such as soda pop and fruit juices. Through the technique, students…

  16. Comment on "Analysis of Citric Acid in Beverages: Use of an Indicator Displacement Assay"

    ERIC Educational Resources Information Center

    Konski, Krzysiek; Saw, Jessica; Torriero, Angel A. J.

    2017-01-01

    This letter comments on the paper "Analysis of Citric Acid in Beverages: Use of an Indicator Displacement Assay" ["J. Chem. Educ." 2010, 87 (8), 832-835 (EJ918557)]. Discrepancies in figures and host:indicator complex behavior are discussed and an alternative experimental protocol presented.

  17. Deletion of a Chitin Synthase Gene in a Citric Acid Producing Strain of Aspergillus niger

    SciTech Connect

    Rinker, Torri E.; Baker, Scott E.

    Citric acid production by the filamentous fungus Aspergillus niger is carried out in a process that causes the organism to drastically alter its morphology. This altered morphology includes hyphal swelling and highly limited polar growth resulting in clumps of swollen cells that eventually aggregate into pellets of approximately 100 microns in diameter. In this pelleted form, A. niger has increased citric acid production as compared to growth in filamentous form. Chitin is a crucial component of the cell wall of filamentous fungi. Alterations in the deposition or production of chitin may have profound effects on the morphology of the organism.more » In order to study the role of chitin synthesis in pellet formation we have deleted a chitin synthase gene (csmA) in Aspergillus niger strain ATCC 11414 using a PCR based deletion construct. This class of chitin synthases is only found in filamentous fungi and is not present in yeasts. The csmA genes contain a myosin motor domain at the N-terminus and a chitin synthesis domain at the C-terminus. They are believed to contribute to the specialized polar growth observed in filamentous fungi that is lacking in yeasts. The csmA deletion strain (csmAΔ) was subjected to minimal media with and without osmotic stabilizers as well as tested in citric acid production media. Without osmotic stabilizers, the mutant germlings were abnormally swollen, primarily in the subapical regions, and contained large vacuoles. However, this swelling is ultimately not inhibitory to growth as the germlings are able to recover and undergo polar growth. Colony formation was largely unaffected in the absence of osmotic stabilizers. In citric acid production media csmAΔ was observed to have a 2.5 fold increase in citric acid production. The controlled expression of this class of chitin synthases may be useful for improving production of organic acids in filamentous fungi.« less

  18. Citric acid compounds of tangerines peel extract (Citrus reticulata) as potential materials teeth whitening

    NASA Astrophysics Data System (ADS)

    Pratiwi, F.; Tinata, J. K.; Prakasa, A. W.; Istiqomah; Hartini, E.; Isworo, S.

    2017-04-01

    Peel of citrus fruit (Citrus reticulata) has a variety of possible chemical compounds that may serve as a potential whitening teeth. This research is conducted on a laboratory scale; therefore, it needs to be developed on an application scale. A quasi-experimental was employed in this study. Citric acid extraction was carried out on the type of Sweet Orange (Citrus Aurantium L), Tangerine (Citrus Reticulata Blanco or Citrus Nobilis), Pomelo (Citrus Maxima Merr, Citrus grandis Osbeck), and Lemon (Citrus Limon Linn). Citric acid’s ability test as teeth whitener was performed on premolar teeth with concentrations of 2.5%, 5%, and 10%. The experiments were replicated in 3 times, and teeth whiteness level was measured using Shade Guide VITA Classical. The result of this research showed that citric acid in every kind of orange peel with various concentration has different abilities on whitening teeth. The highest colour level obtained from Tangerine peel’s citric acid concentration of 5%. Orange peel extract has the best teeth whitening abilities tested by the method of Gass Chromatography to know the active ingredients.

  19. Influence of Citric Acid on the Pink Color and Characteristics of Sous Vide Processed Chicken Breasts During Chill Storage

    PubMed Central

    Lim, Ki-Won

    2015-01-01

    Chicken breast dipped with citric acid (CA) was treated by sous vide processing and stored in a refrigerated state for 0, 3, 6, 9, and 14 d. A non-dipped control group (CON) and three groups dipped in different concentrations of citric acid concentration were analyzed (0.5%, 0.5CIT; 2.0%, 2CIT and 5.0%, 5CIT; w/v). Cooking yield and moisture content increased due to the citric acid. While the redness of the juice and meat in all groups showed significant increase during storage, the redness of the citric acid groups was reduced compared to the control group (p<0.05). The percentage of myoglobin denaturation (PMD) of the CA groups was also increased according to the level of CA during storage. Total aerobic counts, Enterobacteriaceae counts, volatile basic nitrogen and thiobarbituric acid reactive substances (TBARS) were generally lower in the citric acid-treated samples than in untreated ones, indicating extended shelf life of the cooked chicken breast dipped in citric acid solution. The shear force of the 2CIT and 5CIT groups was significantly lower (p<0.05). The findings indicated positive effects in the physicochemical properties and storage ability of sous vide chicken breast at 2% and 5% citric acid concentrations. PMID:26761885

  20. Influence of tartaric acid on linear-nonlinear optical and electrical properties of KH2PO4 crystal

    NASA Astrophysics Data System (ADS)

    Baig, M. I.; Anis, Mohd; Muley, G. G.

    2017-10-01

    KH2PO4 (KDOP) is widely demanded technological crystal for applications in laser driven photonic devices. Therefore, present article is focused to investigate the effect of tartaric acid (TA) on laser induced nonlinear optical properties of KDOP crystal. The optically transparent TA doped KDOP crystal of size 15 × 10 × 04 mm3 has been grown by slow solvent evaporation technique at 35 °C. The structural analysis of pure and TA doped KDOP crystal has been achieved by means of single crystal X-ray diffraction technique. The functional groups of TA doped KDOP crystal has been identified by means of Fourier transform infrared spectral analysis. The UV-visible studies have been performed to determine the optical transparency and evaluate the linear optical constants of pure and TA doped KDOP crystal. The Kurtz-Perry test has been employed to confirm the frequency doubling phenomenon of crystal and the SHG efficiency of TA doped KDOP crystal is found to be 5.68 times higher than that of standard KDP material. The Z-scan technique has been employed to explore the third order nonlinear optical (TONLO) refraction (n2), absorption (β) and susceptibility (χ3) of pure and TA doped KDOP crystal at 632.8 nm. The TA facilitated optical switching in TONLO response of KDOP crystal is found to be an interesting effect to examine. The laser damage threshold of TA doped KDOP crystal has been determined at 1064 nm using the Nd:YAG laser. The comparative electrical analysis on pure and TA doped KDOP crystal has been accomplished by means of dielectric and photoconductivity characterization studies.

  1. Dissolution of Simulated and Radioactive Savannah River Site High-Level Waste Sludges with Oxalic Acid & Citric Acid Solutions

    SciTech Connect

    STALLINGS, MARY

    This report presents findings from tests investigating the dissolution of simulated and radioactive Savannah River Site sludges with 4 per cent oxalic acid and mixtures of oxalic and citric acid previously recommended by a Russian team from the Khlopin Radium Institute and the Mining and Chemical Combine (MCC). Testing also included characterization of the simulated and radioactive waste sludges. Testing results showed the following: Dissolution of simulated HM and PUREX sludges with oxalic and citric acid mixtures at SRTC confirmed general trends reported previously by Russian testing. Unlike the previous Russian testing six sequential contacts of a mixture of oxalicmore » acid citric acids at a 2:1 ratio (v/w) of acid to sludge did not produce complete dissolution of simulated HM and PUREX sludges. We observed that increased sludge dissolution occurred at a higher acid to sludge ratio, 50:1 (v/w), compared to the recommended ratio of 2:1 (v/w). We observed much lower dissolution of aluminum in a simulated HM sludge by sodium hydroxide leaching. We attribute the low aluminum dissolution in caustic to the high fraction of boehmite present in the simulated sludge. Dissolution of HLW sludges with 4 per cent oxalic acid and oxalic/citric acid followed general trends observed with simulated sludges. The limited testing suggests that a mixture of oxalic and citric acids is more efficient for dissolving HM and PUREX sludges and provides a more homogeneous dissolution of HM sludge than oxalic acid alone. Dissolution of HLW sludges in oxalic and oxalic/citric acid mixtures produced residual sludge solids that measured at higher neutron poison to equivalent 235U weight ratios than that in the untreated sludge solids. This finding suggests that residual solids do not present an increased nuclear criticality safety risk. Generally the neutron poison to equivalent 235U weight ratios of the acid solutions containing dissolved sludge components are lower than those in the

  2. Application of carbon and hydrogen stable isotope analyses to detect exogenous citric acid in Japanese apricot liqueur.

    PubMed

    Akamatsu, Fumikazu; Oe, Takaaki; Hashiguchi, Tomokazu; Hisatsune, Yuri; Kawao, Takafumi; Fujii, Tsutomu

    2017-08-01

    Japanese apricot liqueur manufacturers are required to control the quality and authenticity of their liqueur products. Citric acid made from corn is the main acidulant used in commercial liqueurs. In this study, we conducted spiking experiments and carbon and hydrogen stable isotope analyses to detect exogenous citric acid used as an acidulant in Japanese apricot liqueurs. Our results showed that the δ 13 C values detected exogenous citric acid originating from C 4 plants but not from C 3 plants. The δ 2 H values of citric acid decreased as the amount of citric acid added increased, whether the citric acid originated from C 3 or C 4 plants. Commercial liqueurs with declared added acidulant provided higher δ 13 C values and lower δ 2 H values than did authentic liqueurs and commercial liqueurs with no declared added acidulant. Carbon and hydrogen stable isotope analyses are suitable as routine methods for detecting exogenous citric acid in Japanese apricot liqueur. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. A mutation of Aspergillus niger for hyper-production of citric acid from corn meal hydrolysate in a bioreactor.

    PubMed

    Hu, Wei; Liu, Jing; Chen, Ji-hong; Wang, Shu-yang; Lu, Dong; Wu, Qing-hua; Li, Wen-jian

    2014-11-01

    The properties of the screened mutants for hyper-production of citric acid induced by carbon ((12)C(6+)) ion beams and X-ray irradiation were investigated in our current study. Among these mutants, mutant H4002 screened from (12)C(6+) ion irradiation had a higher yield of citric acid production than the parental strain in a 250-ml shaking flash. These expanded submerged experiments in a bioreactor were also carried out for mutant H4002. The results showed that (177.7-196.0) g/L citric acid was accumulated by H4002 through exploiting corn meal hydrolysate (containing initial 200.0-235.7 g/L sugar) with the productivity of (2.96-3.27) g/(L∙h). This was especially true when the initial sugar concentration was 210 g/L, and the best economical citric acid production reached (187.5±0.7) g/L with a productivity of 3.13 g/(L∙h). It was observed that mutant H4002 can utilize low-cost corn meal as a feedstock to efficiently produce citric acid. These results imply that the H4002 strain has the industrial production potentiality for citric acid and offers strong competition for the citric acid industry.

  4. A mutation of Aspergillus niger for hyper-production of citric acid from corn meal hydrolysate in a bioreactor*

    PubMed Central

    Hu, Wei; Liu, Jing; Chen, Ji-hong; Wang, Shu-yang; Lu, Dong; Wu, Qing-hua; Li, Wen-jian

    2014-01-01

    The properties of the screened mutants for hyper-production of citric acid induced by carbon (12C6+) ion beams and X-ray irradiation were investigated in our current study. Among these mutants, mutant H4002 screened from 12C6+ ion irradiation had a higher yield of citric acid production than the parental strain in a 250-ml shaking flash. These expanded submerged experiments in a bioreactor were also carried out for mutant H4002. The results showed that (177.7–196.0) g/L citric acid was accumulated by H4002 through exploiting corn meal hydrolysate (containing initial 200.0–235.7 g/L sugar) with the productivity of (2.96–3.27) g/(L∙h). This was especially true when the initial sugar concentration was 210 g/L, and the best economical citric acid production reached (187.5±0.7) g/L with a productivity of 3.13 g/(L∙h). It was observed that mutant H4002 can utilize low-cost corn meal as a feedstock to efficiently produce citric acid. These results imply that the H4002 strain has the industrial production potentiality for citric acid and offers strong competition for the citric acid industry. PMID:25367793

  5. Potential citric acid exposure and toxicity to Hawaiian hoary bats (Lasiurus cinereus semotus) associated with Eleutherodactylus frog control.

    PubMed

    Pitt, William C; Witmer, Gary W; Jojola, Susan M; Sin, Hans

    2014-04-01

    We examined potential exposure of Hawaiian hoary bats (Lasiurus cinereus semotus) to citric acid, a minimum risk pesticide registered for control of invasive Eleutherodactylus frog populations. Hoary bats are nocturnal insectivores that roost solitarily in foliage, federally listed as endangered, and are endemic to Hawaii. Oral ingestion during grooming of contaminated fur appears to be the principal route by which these bats might be exposed to citric acid. We made assessments of oral toxicity, citric acid consumption, retention of material on fur, and grooming using big brown bats (Eptesicus fuscus) as a surrogate species. We evaluated both ground application and aerial application of 16 % solutions of citric acid during frog control operations. Absorbent bat effigies exposed to ground and aerial operational spray applications retained means of 1.54 and 0.02 g, respectively, of dry citric acid, although retention by the effigies was much higher than bat carcasses drenched in citric acid solutions. A high dose delivered orally (2,811 mg/kg) was toxic to the big brown bats and emesis occurred in 1 bat dosed as low as the 759 mg/kg level. No effect was observed with the lower doses examined (≤ 542 mg/kg). Bats sprayed with 5 ml of 16 % (w/w) citric acid solution showed no evidence of intoxication. In field situations, it is unlikely that bats would be sprayed directly or ingest much citric acid retained by fur. Based on our observations, we believe Hawaiian hoary bats to be at very low risk from harmful exposure to a toxic dose of citric acid during frog control operations.

  6. Quantitative assessment of citric acid in lemon juice, lime juice, and commercially-available fruit juice products.

    PubMed

    Penniston, Kristina L; Nakada, Stephen Y; Holmes, Ross P; Assimos, Dean G

    2008-03-01

    Knowledge of the citric acid content of beverages may be useful in nutrition therapy for calcium urolithiasis, especially among patients with hypocitraturia. Citrate is a naturally-occurring inhibitor of urinary crystallization; achieving therapeutic urinary citrate concentration is one clinical target in the medical management of calcium urolithiasis. When provided as fluids, beverages containing citric acid add to the total volume of urine, reducing its saturation of calcium and other crystals, and may enhance urinary citrate excretion. Information on the citric acid content of fruit juices and commercially-available formulations is not widely known. We evaluated the citric acid concentration of various fruit juices. The citric acid content of 21 commercially-available juices and juice concentrates and the juice of three types of fruits was analyzed using ion chromatography. Lemon juice and lime juice are rich sources of citric acid, containing 1.44 and 1.38 g/oz, respectively. Lemon and lime juice concentrates contain 1.10 and 1.06 g/oz, respectively. The citric acid content of commercially available lemonade and other juice products varies widely, ranging from 0.03 to 0.22 g/oz. Lemon and lime juice, both from the fresh fruit and from juice concentrates, provide more citric acid per liter than ready-to-consume grapefruit juice, ready-to-consume orange juice, and orange juice squeezed from the fruit. Ready-to-consume lemonade formulations and those requiring mixing with water contain < or =6 times the citric acid, on an ounce-for-ounce basis, of lemon and lime juice.

  7. Gas-phase Conformational Analysis of (R,R)-Tartaric Acid, its Diamide, N,N,N',N'- Tetramethyldiamide and Model Compounds

    NASA Astrophysics Data System (ADS)

    Hoffmann, Marcin; Szarecka, Agnieszka; Rychlewski, Jacek

    A review over most recent ab initio studies carried out at both RHF and MP2 levels on (R,R)-tartaric acid (TA), its diamide (DA), tetramethyldiamide (TMDA) and on three prototypic model systems (each of them constitutes a half of the respective parental molecule), i.e. 2-hydroxyacetic acid (HA), 2-hydroxyacetamide (HD) and 2-hydroxy-N,N-dimethylacetamide (HMD) is presented. (R,R)-tartaric acid and the derivatives have been completely optimized at RHF/6-31G* level and subsequently single-point energies of all conformers have been calculated with the use of second order perturbation theory according to the scheme: MP2/6-31G*//RHF/6-31G*. In the complete optimization of the model molecules at RHF level we have employed relatively large basis sets, augmented with polarisation and diffuse functions, namely 3-21G, 6-31G*, 6-31++G** and 6-311++G**. Electronic correlation has been included with the largest basis set used in this study, i.e. MP2/6-311++G**//RHF/6-311++G** single-point energy calculations have been performed. General confomational preferences of tartaric acid derivatives have been analysed as well as an attempt has been made to define main factors affecting the conformational behaviour of these molecules in the isolated state, in particular, the role and stability of intramolecular hydrogen bonding. In the case of the model compounds, our study principally concerned the conformational preferences and hydrogen bonding structure within the [alpha]-hydroxy-X moiety, where X=COOH, CONH2, CON(CH3)2.

  8. Extraction of rare earth elements from a contaminated cropland soil using nitric acid, citric acid, and EDTA.

    PubMed

    Tang, Hailong; Shuai, Weitao; Wang, Xiaojing; Liu, Yangsheng

    2017-08-01

    Rare earth elements (REEs) contamination to the surrounding soil has increased the concerns of health risk to the local residents. Soil washing was first attempted in our study to remediate REEs-contaminated cropland soil using nitric acid, citric acid, and ethylene diamine tetraacetic acid (EDTA) for soil decontamination and possible recovery of REEs. The extraction time, washing agent concentration, and pH value of the washing solution were optimized. The sequential extraction analysis proposed by Tessier was adopted to study the speciation changes of the REEs before and after soil washing. The extract containing citric acid was dried to obtain solid for the X-ray fluorescence (XRF) analysis. The results revealed that the optimal extraction time was 72 h, and the REEs extraction efficiency increased as the agent concentration increased from 0.01 to 0.1 mol/L. EDTA was efficient to extract REEs over a wide range of pH values, while citric acid was around pH 6.0. Under optimized conditions, the average extraction efficiencies of the major REEs in the contaminated soil were 70.96%, 64.38%, and 62.12% by EDTA, nitric acid, and citric acid, respectively. The sequential extraction analyses revealed that most soil-bounded REEs were mobilized or extracted except for those in the residual fraction. Under a comprehensive consideration of the extraction efficiency and the environmental impact, citric acid was recommended as the most suitable agent for extraction of the REEs from the contaminated cropland soils. The XRF analysis revealed that Mn, Al, Si, Pb, Fe, and REEs were the major elements in the extract indicating a possibile recovery of the REEs.

  9. By-products from the biodiesel chain as a substrate to citric acid production by solid-state fermentation.

    PubMed

    Schneider, Manuella; Zimmer, Gabriela F; Cremonese, Ezequiel B; de C de S Schneider, Rosana; Corbellini, Valeriano A

    2014-07-01

    In this study, we propose the use of tung cake for the production of organic acids, with an emphasis on citric acid by solid-state fermentation. We evaluated the conditions of production and the by-products from the biodiesel chain as raw materials involved in this bioprocess. First, we standardized the conditions of solid-state fermentation in tung cake with and without residual fat and with different concentrations of glycerine using the fungus Aspergillus niger The solid-state fermentation process was monitored for 7 days considering the biomass growth and pH level. Citric acid production was determined by high-performance liquid chromatography. Fungal development was better in the crude tung cake, consisting of 20% glycerine. The highest citric acid yield was 350 g kg(-1) of biomass. Therefore, the solid-state fermentation of the tung cake with glycerine led to citric acid production using the Aspergillus niger fungus. © The Author(s) 2014.

  10. Chemical modification of chitosan film via surface grafting of citric acid molecular to promote the biomineralization

    NASA Astrophysics Data System (ADS)

    Liu, Yang; Shen, Xin; Zhou, Huan; Wang, Yingjun; Deng, Linhong

    2016-05-01

    We develop a novel chitosan-citric acid film (abbreviated as CS-CA) suitable for biomedical applications in this study. In this CS-CA film, the citric acid, which is a harmless organic acid has been extensively investigated as a modifying agent on carbohydrate polymers, was cross-linked by 1-Ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS) onto the surface of chitosan (CS) film. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) confirms the graft copolymerization of the modified chitosan film (CS-CA). Surface wettability, moisturizing performance, the capacity of mineralization in vitro and biocompatibility of the films were characterized. After modification, this CS-CA film has good hydrophilicity. It is very evident that the citric acid grafting treatment significantly promotes the biomineralization of the chitosan based substrates. Cell experiments show that the MC3T3-E1 osteoblasts can adhere and proliferate well on the surface of CS-CA film. This CS-CA film, which can be prepared in large quantities and at low cost, should have potential application in bone tissue engineering.

  11. Effect of EDTA and citric acid on absorption of heavy metals and growth of Moso bamboo.

    PubMed

    Zhang, Xiaowei; Zhong, Bin; Shafi, Mohammad; Guo, Jia; Liu, Chen; Guo, Hua; Peng, Danli; Wang, Ying; Liu, Dan

    2018-04-30

    The effect of EDTA and citric acid on accumulation, toxicity of heavy metals (Cu, Zn, Cd, and Pb), and growth of Moso bamboo was investigated in current experiment. The availability of heavy metals in soil and its uptake by plants has indicated toxicity. The results revealed that EDTA and citric acid has reduced biomass of Moso bamboo but non-significant difference in biomass was observed compared with control. Application of EDTA (10 mmol kg -1 ) has significantly improved copper (Cu) by 56.5 and 84.9% in roots and above ground parts of plants. Application of EDTA (10 mmol kg -1 ) has significantly enhanced lead (Pb) by 51.8 and 210.8% in roots and above ground parts of Moso bamboo. Furthermore, treatment of EDTA has significantly improved activities of water-soluble Cd, Cu, and Pb in soil by 98.9, 70.1, and 73.1 times compared with control. In case of contents of diethylenetriaminepentaacetic acid (DTPA)-extractable metals, the treatment of EDTA (10 mmol kg -1 ) has produced maximum increase of 244.5 mg kg -1 Zn and 157.9 mg kg -1 Pb, respectively. It is concluded that effect of EDTA was superior compared with citric acid for improvement of phytoremediation potential of Moso bamboo.

  12. Enhanced concentrations of citric acid in spring aerosols collected at the Gosan background site in East Asia

    NASA Astrophysics Data System (ADS)

    Jung, Jinsang; Kawamura, Kimitaka

    2011-09-01

    In order to investigate water-soluble dicarboxylic acids and related compounds in the aerosol samples under the Asian continent outflow, total suspended particle (TSP) samples ( n = 32) were collected at the Gosan site in Jeju Island over 2-5 days integration during 23 March-1 June 2007 and 16-24 April 2008. The samples were analyzed for water-soluble dicarboxylic acids, ketocarboxylic acids, and α-dicarbonyls using a capillary gas chromatography technique. We found elevated concentrations of atmospheric citric acid (range: 20-320 ng m -3) in the TSP samples during mid- to late April of 2007 and 2008. To specify the sources of citric acid, dicarboxylic acids and related compounds were measured in the pollen sample collected at the Gosan site (Pollen_Gosan), authentic pollen samples from Japanese cedar ( Cryptomeria) (Pollen_cedar) and Japanese cypress ( Chamaecyparis obtusa) (Pollen_cypress), and tangerine fruit produced from Jeju Island. Citric acid (2790 ng in unit mg of pollen mass) was found as most abundant species in the Pollen_Gosan, followed by oxalic acid (2390 ng mg -1). Although citric acid was not detected in the Pollen_cedar and Pollen_cypress as major species, it was found as a dominant species in the tangerine juice while malic acid was detected as major species in the tangerine peel, followed by oxalic and citric acids. Since Japanese cedar trees are planted around tangerine farms to prevent strong winds from the Pacific Ocean, citric acid that may be directly emitted from tangerine is likely adsorbed on pollens emitted from Japanese cedar and then transported to the Gosan site. Much lower malic/citric acid ratios obtained under cloudy condition than clear condition suggest that malic acid may rapidly decompose to lower molecular weight compounds such as oxalic and malonic acids (

  13. Citric Acid and Quinine Share Perceived Chemosensory Features Making Oral Discrimination Difficult in C57BL/6J Mice

    PubMed Central

    Treesukosol, Yada; Mathes, Clare M.

    2011-01-01

    Evidence in the literature shows that in rodents, some taste-responsive neurons respond to both quinine and acid stimuli. Also, under certain circumstances, rodents display some degree of difficulty in discriminating quinine and acid stimuli. Here, C57BL/6J mice were trained and tested in a 2-response operant discrimination task. Mice had severe difficulty discriminating citric acid from quinine and 6-n-propylthiouracil (PROP) with performance slightly, but significantly, above chance. In contrast, mice were able to competently discriminate sucrose from citric acid, NaCl, quinine, and PROP. In another experiment, mice that were conditioned to avoid quinine by pairings with LiCl injections subsequently suppressed licking responses to quinine and citric acid but not to NaCl or sucrose in a brief-access test, relative to NaCl-injected control animals. However, mice that were conditioned to avoid citric acid did not display cross-generalization to quinine. These mice significantly suppressed licking only to citric acid, and to a much lesser extent NaCl, compared with controls. Collectively, the findings from these experiments suggest that in mice, citric acid and quinine share chemosensory features making discrimination difficult but are not perceptually identical. PMID:21421543

  14. Citric acid induced W18O49 electrochromic films with enhanced optical modulation

    NASA Astrophysics Data System (ADS)

    Xie, Junliang; Song, Bin; Zhao, Gaoling; Han, Gaorong

    2018-06-01

    Electrochromic materials exhibit promising applications in energy-saving fields for their ability to control heat from outdoors. Nanostructured W18O49 has drawn attention for its one-dimensional structure to transfer charge efficiently as a remarkable electrochromic material. W18O49 bi-layer films were fabricated through a facile one-step solvothermal process with citric acid as a chelating agent. The addition of citric acid improved the deposition on the substance, and a nanostructured film with a denser layer at the bottom and a tussock-like upper layer was obtained. The bi-layer film exhibited an enhanced optical modulation of 68.7%, a coloration efficiency of 82.1 cm2/C with stability over 400 cycles, and fast response times (1.4 s and 2.3 s for bleaching and coloring), with expectation to be applied in the electrochromic field.

  15. A Biodegradable Thermoset Polymer Made by Esterification of Citric Acid and Glycerol

    PubMed Central

    Halpern, Jeffrey M.; Urbanski, Richard; Weinstock, Allison K.; Iwig, David F.; Mathers, Robert T.; von Recum, Horst

    2014-01-01

    A new biomaterial, a degradable thermoset polymer, was made from simple, economical, biocompatable monomers without the need for a catalyst. Glycerol and citric acid, non-toxic and renewable reagents, were crosslinked by a melt polymerization reaction at temperatures from 90-150°C. Consistent with a condensation reaction, water was determined to be the primary byproduct. The amount of crosslinking was controlled by the reaction conditions, including temperature, reaction time, and ratio between glycerol and citric acid. Also, the amount of crosslinking was inversely proportional to the rate of degradation. As a proof-of-principle for drug delivery applications, gentamicin, an antibiotic, was incorporated into the polymer with preliminary evaluations of antimicrobial activity. The polymers incorporating gentamicin had significantly better bacteria clearing of Staphylococcus aureus compared to non-gentamicin gels for up to nine days. PMID:23737239

  16. Influence of calcium on fungal growth, hyphal morphology and citric acid production in Aspergillus niger.

    PubMed

    Pera, L M; Callieri, D A

    1997-01-01

    Addition of 0.5 g/L CaCl2 to the fermentation medium lowered the final biomass dry mass by 35% and increased the uptake of phosphate and sucrose, and the production of citric acid by 15, 35 and 50%, respectively. In a medium deprived of Ca2+ the microorganism displayed both a pelleted and a filamentous form of growth, the hyphae being scarcely branched, without bulbous cells. An addition of Ca2+ induced a pelleted form of growth, highly branched hyphae and numerous bulbous cells. Bulbous cells growing in the presence of Ca2+ exhibited cell walls composed of laminated layers, and featured vesicles associated with the wall and/or the cell membrane, containing numerous inclusions. The cytotoxic effect of high concentrations of citric acid in the medium as well as an increase of the activity of N-acetyl-beta-D-glucosaminidase, a lytic enzyme, might be involved in these morphological changes.

  17. Citric acid treatment of chronic nonhealing ulcerated tophaceous gout with bursitis.

    PubMed

    Nagoba, Basavaraj S; Punpale, Ajay; Poddar, Ashok; Suryawanshi, Namdev M; Swami, Ganesh A; Selkar, Sohan P

    2013-12-01

    The ulceration associated with gout tophi is very difficult to treat because of impaired and halted local inflammatory response resulting from the gout treatment regimen. We report chronic nonhealing tophaceous gout with bursitis in an 80-year-old male, not responding to conventional treatment modality for months together. This nonhealing ulcer was treated successfully with local application of 3% citric acid ointment for 22 days.

  18. Pd/C Synthesized with Citric Acid: An Efficient Catalyst for Hydrogen Generation from Formic Acid/Sodium Formate

    PubMed Central

    Wang, Zhi-Li; Yan, Jun-Min; Wang, Hong-Li; Ping, Yun; Jiang, Qing

    2012-01-01

    A highly efficient hydrogen generation from formic acid/sodium formate aqueous solution catalyzed by in situ synthesized Pd/C with citric acid has been successfully achieved at room temperature. Interestingly, the presence of citric acid during the formation and growth of the Pd nanoparticles on carbon can drastically enhance the catalytic property of the resulted Pd/C, on which the conversion and turnover frequency for decomposition of formic acid/sodium formate system can reach the highest values ever reported of 85% within 160 min and 64 mol H2 mol−1 catalyst h−1, respectively, at room temperature. The present simple, low cost, but highly efficient CO-free hydrogen generation system at room temperature is believed to greatly promote the practical application of formic acid system on fuel cells. PMID:22953041

  19. Changes of lipid and fatty acid absorption induced by high dose of citric acid ester and lecithin emulsifiers.

    PubMed

    Sadouki, Mohamed; Bouchoucha, Michel

    2014-09-01

    To describe the effect of two food emulsifiers, lecithin (E322) and citric acid esters of mono-and diglycerides of fatty acids (E472c), on the intestinal absorption of lipids. The experiment was conducted on 24 male Wistar rats randomly assigned in three groups. For two groups of six rats, 30% of the lipid intake was replaced with lecithin (L) or citric acid ester of mono and diglycerides, (E); the remaining 12 rats were the control group (C). Diet and fecal fat analysis was used to determine the apparent lipid absorption (ALA) and fatty acids. ALA was significantly lower in the group E than in the groups C and L (p < 0.001). ALA of long saturated chain fatty acids decreased while the length of the carbon chains increased, and this decrease was higher in the group E. E472c emulsifier decreased the intestinal absorption of lipids.

  20. Inactivation of Foot-and-Mouth Disease Virus by Citric Acid and Sodium Carbonate with Deicers

    PubMed Central

    Hong, Jang-Kwan; You, Su-Hwa; Kim, Su-Mi; Tark, Dongseob; Lee, Hyang-Sim; Ko, Young-Joon; Seo, Min-Goo; Park, Jong-Hyeon; Kim, Byounghan

    2015-01-01

    Three out of five outbreaks of foot-and-mouth disease (FMD) since 2010 in the Republic of Korea have occurred in the winter. At the freezing temperatures, it was impossible to spray disinfectant on the surfaces of vehicles, roads, and farm premises because the disinfectant would be frozen shortly after discharge and the surfaces of the roads or machines would become slippery in cold weather. In this study, we added chemical deicers (ethylene glycol, propylene glycol, sodium chloride, calcium chloride, ethyl alcohol, and commercial windshield washer fluid) to keep disinfectants (0.2% citric acid and 4% sodium carbonate) from freezing, and we tested their virucidal efficacies under simulated cold temperatures in a tube. The 0.2% citric acid could reduce the virus titer 4 logs at −20°C with all the deicers. On the other hand, 4% sodium carbonate showed little virucidal activity at −20°C within 30 min, although it resisted being frozen with the function of the deicers. In conclusion, for the winter season, we may recommend the use of citric acid (>0.2%) diluted in 30% ethyl alcohol or 25% sodium chloride solvent, depending on its purpose. PMID:26319879

  1. Synthesis and characterization of hydrogel films of carboxymethyl tamarind gum using citric acid.

    PubMed

    Mali, Kailas K; Dhawale, Shashikant C; Dias, Remeth J

    2017-12-01

    The objective of this study was to synthesize and characterize citric acid crosslinked carboxymethyl tamarind gum (CMTG) hydrogels films. The hydrogel films were characterized by Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, solid state 13 C-nuclear magnetic resonance ( 13 C NMR) spectroscopy and differential scanning calorimeter (DSC). The prepared hydrogel films were evaluated for the carboxyl content and swelling ratio. The model drug moxifloxacin hydrochloride was loaded into hydrogels films and drug release was studied at pH 7.4. The hemolysis assay was used to study the biocompatibility of hydrogel films. The results of ATR-FTIR, solid state 13 C NMR and DSC confirmed the formation of ester crosslinks between citric acid and CMTG. The total carboxyl content of hydrogel film was found to be decreased when amount of CMTG was increased. The swelling of hydrogel film was found to be decreased with increase in curing temperature and time. CMTG hydrogel films showed high drug loading with non-Fickian release mechanism suggesting controlled release of drug. The hydrogel films were found to be biocompatible. It can be concluded that the citric acid can be used for the preparation of CMTG hydrogel films. Further, CMTG hydrogel film can be used potentially for controlled release of drug. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Phosphate recovery through struvite-family crystals precipitated in the presence of citric acid: mineralogical phase and morphology evaluation.

    PubMed

    Perwitasari, D S; Edahwati, L; Sutiyono, S; Muryanto, S; Jamari, J; Bayuseno, A P

    2017-11-01

    Precipitation strategy of struvite-family crystals is presented in this paper to recover phosphate and potassium from a synthetic wastewater in the presence of citric acid at elevated temperature. The crystal-forming solutions were prepared from crystals of MgCl 2 and NH 4 H 2 PO 4 with a molar ratio of 1:1:1 for Mg +2 , [Formula: see text], and [Formula: see text], and the citric acid (C 6 H 8 O 7 ) was prepared (1.00 and 20.00 ppm) from citric acid crystals. The Rietveld analysis of X-ray powder diffraction pattern confirmed a mixed product of struvite, struvite-(K), and newberyite crystallized at 30°C in the absence of citric acid. In the presence of citric acid at 30° and 40°C, an abundance of struvite and struvite-(K) were observed. A minute impurity of sylvite and potassium peroxide was unexpectedly found in certain precipitates. The crystal solids have irregular flake-shaped morphology, as shown by scanning electron microscopy micrograph. All parameters (citric acid, temperature, pH, Mg/P, and N/P) were deliberately arranged to control struvite-family crystals precipitation.

  3. Continuous citric acid production in repeated-fed batch fermentation by Aspergillus niger immobilized on a new porous foam.

    PubMed

    Yu, Bin; Zhang, Xin; Sun, Wenjun; Xi, Xun; Zhao, Nan; Huang, Zichun; Ying, Zhuojun; Liu, Li; Liu, Dong; Niu, Huanqing; Wu, Jinglan; Zhuang, Wei; Zhu, Chenjie; Chen, Yong; Ying, Hanjie

    2018-06-20

    The efficiency of current methods for industrial production of citric acid is limited. To achieve continuous citric acid production with enhanced yield and reduced cost, immobilized fermentation was employed in an Aspergillus niger 831 repeated fed-batch fermentation system. We developed a new type of material (PAF201), which was used as a carrier for the novel adsorption immobilization system. Hydrophobicity, pore size and concentration of carriers were researched in A. niger immobilization. The efficiency of the A. niger immobilization process was analyzed by scanning electron microscopy. Then eight-cycle repeated fed-batch cultures for citric acid production were carried out over 600 h, which showed stable production with maximum citric acid concentrations and productivity levels of 162.7 g/L and 2.26 g L -1  h -1 , respectively. Compared with some other literatures about citric acid yield, PAF201 immobilization system is 11.3% higher than previous results. These results indicated that use of the new adsorption immobilization system could greatly improve citric acid productivity in repeated fed-batch fermentation. Moreover, these results could provide a guideline for A.niger or other filamentous fungi immobilization in industry. Copyright © 2018 Elsevier B.V. All rights reserved.

  4. Growth/no growth interfaces of table olive related yeasts for natamycin, citric acid and sodium chloride.

    PubMed

    Arroyo-López, F N; Bautista-Gallego, J; Romero-Gil, V; Rodríguez-Gómez, F; Garrido-Fernández, A

    2012-04-16

    The present work uses a logistic/probabilistic model to obtain the growth/no growth interfaces of Saccharomyces cerevisiae, Wickerhamomyces anomalus and Candida boidinii (three yeast species commonly isolated from table olives) as a function of the diverse combinations of natamycin (0-30 mg/L), citric acid (0.00-0.45%) and sodium chloride (3-6%). Mathematical models obtained individually for each yeast species showed that progressive concentrations of citric acid decreased the effect of natamycin, which was only observed below 0.15% citric acid. Sodium chloride concentrations around 5% slightly increased S. cerevisiae and C. boidinii resistance to natamycin, although concentrations above 6% of NaCl always favoured inhibition by this antimycotic. An overall growth/no growth interface, built considering data from the three yeast species, revealed that inhibition in the absence of citric acid and at 4.5% NaCl can be reached using natamycin concentrations between 12 and 30 mg/L for growth probabilities between 0.10 and 0.01, respectively. Results obtained in this survey show that is not advisable to use jointly natamycin and citric acid in table olive packaging because of the observed antagonistic effects between both preservatives, but table olives processed without citric acid could allow the application of the antifungal. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. Effect of Tartaric Acid on Hydration of a Sodium-Metasilicate-Activated Blend of Calcium Aluminate Cement and Fly Ash F

    DOE PAGES

    Pyatina, Tatiana; Sugama, Toshifumi; Moon, Juhyuk; ...

    2016-05-27

    An alkali-activated blend of aluminum cement and class F fly ash is an attractive solution for geothermal wells where cement is exposed to significant thermal shocks and aggressive environments. Set-control additives enable the safe cement placement in a well but may compromise its mechanical properties. Here, this work evaluates the effect of a tartaric-acid set retarder on phase composition, microstructure, and strength development of a sodium-metasilicate-activated calcium aluminate/fly ash class F blend after curing at 85 °C, 200 °C or 300 °C. The hardened materials were characterized with X-ray diffraction, thermogravimetric analysis, X-ray computed tomography, and combined scanning electron microscopy/energy-dispersivemore » X-ray spectroscopy and tested for mechanical strength. With increasing temperature, a higher number of phase transitions in non-retarded specimens was found as a result of fast cement hydration. The differences in the phase compositions were also attributed to tartaric acid interactions with metal ions released by the blend in retarded samples. The retarded samples showed higher total porosity but reduced percentage of large pores (above 500 µm) and greater compressive strength after 300 °C curing. Lastly, mechanical properties of the set cements were not compromised by the retarder.« less

  6. Effect of Tartaric Acid on Hydration of a Sodium-Metasilicate-Activated Blend of Calcium Aluminate Cement and Fly Ash F

    PubMed Central

    Pyatina, Tatiana; Sugama, Toshifumi; Moon, Juhyuk; James, Simon

    2016-01-01

    An alkali-activated blend of aluminum cement and class F fly ash is an attractive solution for geothermal wells where cement is exposed to significant thermal shocks and aggressive environments. Set-control additives enable the safe cement placement in a well but may compromise its mechanical properties. This work evaluates the effect of a tartaric-acid set retarder on phase composition, microstructure, and strength development of a sodium-metasilicate-activated calcium aluminate/fly ash class F blend after curing at 85 °C, 200 °C or 300 °C. The hardened materials were characterized with X-ray diffraction, thermogravimetric analysis, X-ray computed tomography, and combined scanning electron microscopy/energy-dispersive X-ray spectroscopy and tested for mechanical strength. With increasing temperature, a higher number of phase transitions in non-retarded specimens was found as a result of fast cement hydration. The differences in the phase compositions were also attributed to tartaric acid interactions with metal ions released by the blend in retarded samples. The retarded samples showed higher total porosity but reduced percentage of large pores (above 500 µm) and greater compressive strength after 300 °C curing. Mechanical properties of the set cements were not compromised by the retarder. PMID:28773543

  7. Effect of Tartaric Acid on Hydration of a Sodium-Metasilicate-Activated Blend of Calcium Aluminate Cement and Fly Ash F.

    PubMed

    Pyatina, Tatiana; Sugama, Toshifumi; Moon, Juhyuk; James, Simon

    2016-05-27

    An alkali-activated blend of aluminum cement and class F fly ash is an attractive solution for geothermal wells where cement is exposed to significant thermal shocks and aggressive environments. Set-control additives enable the safe cement placement in a well but may compromise its mechanical properties. This work evaluates the effect of a tartaric-acid set retarder on phase composition, microstructure, and strength development of a sodium-metasilicate-activated calcium aluminate/fly ash class F blend after curing at 85 °C, 200 °C or 300 °C. The hardened materials were characterized with X-ray diffraction, thermogravimetric analysis, X-ray computed tomography, and combined scanning electron microscopy/energy-dispersive X-ray spectroscopy and tested for mechanical strength. With increasing temperature, a higher number of phase transitions in non-retarded specimens was found as a result of fast cement hydration. The differences in the phase compositions were also attributed to tartaric acid interactions with metal ions released by the blend in retarded samples. The retarded samples showed higher total porosity but reduced percentage of large pores (above 500 µm) and greater compressive strength after 300 °C curing. Mechanical properties of the set cements were not compromised by the retarder.

  8. Cocrystal Screening of Ibuprofen with Oxalic Acid and Citric Acid via Grinding Method

    NASA Astrophysics Data System (ADS)

    Othman, M. F.; Anuar, N.; Rahman, S. Ad; Taifuddin, N. A. Ahmad

    2018-05-01

    Ibuprofen is a Class II Biological Safety Class (BSC) drugs used for relief of arthritis, as an analgesic and possesses the effect of antiplatelet. The major problem involves in ibuprofen is it has a low solubility and high permeability thus causes an unsatisfactory therapeutic effect to humans. Thus, in this work, alteration of ibuprofen’s physicochemical properties is conducted by means of cocrystallization technique. Co-crystallizations of ibuprofen were prepared with selected coformers using dry grinding and liquid assisted grinding (LAG) techniques in different molar ratios while ethanol and propanol were used as a solvent. The new crystalline forms were identified and characterized by differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD) and fourier transform infrared spectroscopy (FTIR). Analysis for Ibuprofen-Citric acid (IBP-CA) system, co-crystal was successfully formed in 1:2, 1:3, 2:1 and 3:1 molar ratios for neat grinding method although the co-crystal produced is unstable. Meanwhile, for Ibuprofen-Oxalic acid (IBP-OA) system, the co-crystal formation was identified only in 1:1, 1:2 and 1:3 molar ratios for the neat grinding method. LAG method shows that co-crystal formation was unsuccessful in both solvents for IBP-CA, while IBP-OA co-crystal was formed in the molar ratio 1:1, 2:1 and 3:1 in ethanol, and 2:1 and 3:1 in propanol.

  9. Discovery of a Chemical Modification by Citric Acid in a Recombinant Monoclonal Antibody

    PubMed Central

    2015-01-01

    Recombinant therapeutic monoclonal antibodies exhibit a high degree of heterogeneity that can arise from various post-translational modifications. The formulation for a protein product is to maintain a specific pH and to minimize further modifications. Generally Recognized as Safe (GRAS), citric acid is commonly used for formulation to maintain a pH at a range between 3 and 6 and is generally considered chemically inert. However, as we reported herein, citric acid covalently modified a recombinant monoclonal antibody (IgG1) in a phosphate/citrate-buffered formulation at pH 5.2 and led to the formation of so-called “acidic species” that showed mass increases of 174 and 156 Da, respectively. Peptide mapping revealed that the modification occurred at the N-terminus of the light chain. Three additional antibodies also showed the same modification but displayed different susceptibilities of the N-termini of the light chain, heavy chain, or both. Thus, ostensibly unreactive excipients under certain conditions may increase heterogeneity and acidic species in formulated recombinant monoclonal antibodies. By analogy, other molecules (e.g., succinic acid) with two or more carboxylic acid groups and capable of forming an anhydride may exhibit similar reactivities. Altogether, our findings again reminded us that it is prudent to consider formulations as a potential source for chemical modifications and product heterogeneity. PMID:25136741

  10. Geobiochemistry of metabolism: Standard state thermodynamic properties of the citric acid cycle

    NASA Astrophysics Data System (ADS)

    Canovas, Peter A.; Shock, Everett L.

    2016-12-01

    Integrating microbial metabolism into geochemical modeling allows assessments of energy and mass transfer between the geosphere and the microbial biosphere. Energy and power supplies and demands can be assessed from analytical geochemical data given thermodynamic data for compounds involved in catabolism and anabolism. Results are reported here from a critique of the available standard state thermodynamic data for organic acids and acid anions involved in the citric acid cycle (also known as the tricarboxylic acid cycle or the Krebs cycle). The development of methods for estimating standard state data unavailable from experiments is described, together with methods to predict corresponding values at elevated temperatures and pressures using the revised Helgeson-Kirkham-Flowers (HKF) equation of state for aqueous species. Internal consistency is maintained with standard state thermodynamic data for organic and inorganic aqueous species commonly used in geochemical modeling efforts. Standard state data and revised-HKF parameters are used to predict equilibrium dissociation constants for the organic acids in the citric acid cycle, and to assess standard Gibbs energies of reactions for each step in the cycle at elevated temperatures and pressures. The results presented here can be used with analytical data from natural and experimental systems to assess the energy and power demands of microorganisms throughout the habitable ranges of pressure and temperature, and to assess the consequences of abiotic organic compound alteration processes at conditions of subsurface aquifers, sedimentary basins, hydrothermal systems, meteorite parent bodies, and ocean worlds throughout the solar system.

  11. Effects of tempering (annealing), acid hydrolysis, low-citric acid substitution on chemical and physicochemical properties of starches of four yam (Dioscorea spp.) cultivars.

    PubMed

    Falade, Kolawole O; Ayetigbo, Oluwatoyin E

    2017-05-01

    The effects of tempering (annealing), acid hydrolysis and low-citric acid substitution on chemical and physicochemical properties of starches of four Nigerian yam cultivars were investigated. Crude fat and protein contents of the native starches decreased significantly after the modifications, while nitrogen-free extract increased significantly with acid hydrolysis and citric acid substitution. Acid hydrolysis and low-citric acid substitution reduced the least concentration for gel formation of the starches from 4 to 2% w/v, but tempering had no effect. Swelling power of the starches reduced significantly, and water solubility increased significantly at 75 and 85 °C, especially with acid hydrolysis and low-citric acid substitution. However, tempering significantly reduced starch solubility in the four cultivars. Paste clarity of starches of white (29.17%), water (18.90%), yellow (30.90%) and bitter (10.57%) yams reduced significantly with tempering to 14.43, 11.83, 16.93 and 7.27%, but increased significantly with acid hydrolysis to 41.40, 35.37, 28.77 and 32.33%, and low-citric acid substitution to 36.60, 44.17, 50.67 and 14.33%, respectively. Pasting properties such as peak, trough, breakdown, final, and setback viscosities and peak time of native starches reduced significantly with acid hydrolysis and low-citric acid substitution, however, tempering significantly increased their pasting temperature, peak time, setback and final viscosities.

  12. Sudden substrate dilution induces a higher rate of citric acid production by Aspergillus niger.

    PubMed Central

    Legisa, M; Gradisnik-Grapulin, M

    1995-01-01

    On the basis of the present knowledge of Aspergillus niger metabolism during citric acid fermentation, an idea on how to improve the process was formed. Initially, a higher sucrose concentration was used for the germination of spores, which caused a higher intracellular level of the osmoregulator, glycerol, to be present. When citric acid started to be excreted into the medium, the substrate was suddenly diluted. Optimization of this procedure resulted in a nearly tripled volumetric rate (grams per liter per hour) of acid production, while the overall fermentation time was halved compared with the usual batch process. Yet, a characteristic delay was observed at the start of the acid excretion after the dilution. Hypo-osmotic shock caused a prominent elevation of intracellular cyclic AMP levels. Simultaneously, the specific activity of 6-phosphofructo-1-kinase increased significantly, probably due to phosphorylation of the protein molecule by cyclic AMP-dependent protein kinase. Specific 6-phosphofructo-1-kinase activity was much higher in the treated than in the normally growing mycelium. The metabolic flow through glycolysis was expected to be higher, which should contribute to a higher volumetric rate of acid production. PMID:7618885

  13. Sudden substrate dilution induces a higher rate of citric acid production by Aspergillus niger.

    PubMed

    Legisa, M; Gradisnik-Grapulin, M

    1995-07-01

    On the basis of the present knowledge of Aspergillus niger metabolism during citric acid fermentation, an idea on how to improve the process was formed. Initially, a higher sucrose concentration was used for the germination of spores, which caused a higher intracellular level of the osmoregulator, glycerol, to be present. When citric acid started to be excreted into the medium, the substrate was suddenly diluted. Optimization of this procedure resulted in a nearly tripled volumetric rate (grams per liter per hour) of acid production, while the overall fermentation time was halved compared with the usual batch process. Yet, a characteristic delay was observed at the start of the acid excretion after the dilution. Hypo-osmotic shock caused a prominent elevation of intracellular cyclic AMP levels. Simultaneously, the specific activity of 6-phosphofructo-1-kinase increased significantly, probably due to phosphorylation of the protein molecule by cyclic AMP-dependent protein kinase. Specific 6-phosphofructo-1-kinase activity was much higher in the treated than in the normally growing mycelium. The metabolic flow through glycolysis was expected to be higher, which should contribute to a higher volumetric rate of acid production.

  14. Model-based design of a pilot-scale simulated moving bed for purification of citric acid from fermentation broth.

    PubMed

    Wu, Jinglan; Peng, Qijun; Arlt, Wolfgang; Minceva, Mirjana

    2009-12-11

    One of the conventional processes used for the recovery of citric acid from its fermentation broth is environmentally harmful and cost intensive. In this work an innovative benign process, which comprises simulated moving bed (SMB) technology and use of a tailor-made tertiary poly(4-vinylpyridine) (PVP) resin as a stationary phase is proposed. This paper focuses on a model-based design of the operation conditions for an existing pilot-scale SMB plant. The SMB unit is modeled on the basis of experimentally determined hydrodynamics, thermodynamics and mass transfer characteristics in a single chromatographic column. Three mathematical models are applied and validated for the prediction of the experimentally attained breakthrough and elution profiles of citric acid and the main impurity component (glucose). The transport dispersive model was selected for the SMB simulation and design studies, since it gives a satisfactory prediction of the elution profiles within acceptable computational time. The equivalent true moving bed (TMB) and SMB models give a good prediction of the experimentally attained SMB separation performances, obtained with a real clarified and concentrated fermentation broth as a feed mixture. The SMB separation requirements are set to at least 99.8% citric acid purity and 90% citric acid recovery in the extract stream. The complete regeneration in sections 1 and 4 is unnecessary. Therefore the net flow rates in all four SMB sections have been considered in the unit design. The influences of the operating conditions (the flow rate in each section, switching time and unit configuration) on the SMB performances were investigated systematically. The resulting SMB design provides 99.8% citric acid purity and 97.2% citric acid recovery in the extract. In addition the citric acid concentration in the extract is a half of its concentration in the pretreated fermentation broth (feed).

  15. Monitoring of the fermentation media of citric acid by the trimethylsilyl derivatives of the organic acids formed.

    PubMed

    Ghassempour, Alireza; Nojavan, Saeed; Talebpour, Zahra; Amiri, Ali Asghar; Najafi, Nahid Mashkouri

    2004-10-20

    In this approach, a derivatization method is described for monitoring of organic acids in fermentation media without any separation step. The aqueous phase of fermentation media was evaporated and heated in a silylation reagent to form trimethylsilyl (TMS) derivatives. The silylated compounds are analyzed by 29Si nuclear magnetic resonance (29Si NMR) and gas chromatography-mass spectrometry (GC-MS). 29Si NMR can qualitatively monitor the components produced in the Krebs cycle. Quantification of these compounds is investigated by using selected ion monitoring mode of mass spectrometry. In this mode, mass to charge (m/z) values of their [M - 15]+ ions, which are 465, 275, 247, 221, 335, 251, and 313 of TMS derivatives of citric, alpha-ketoglutaric, succinic, fumaric, l-malic, oxaloacetic, and palmitic (as an internal standard), acids, respectively, are used. The limit of detection and the linear working range for derivatized citric acid were found to be 0.1 mg L(-1) and 10-3 x 10(4) mg L(-1). The relative standard deviation of the method for five replicates was 2.1%. The average recovery efficiency for citric acid added to culture media was approximately 97.2%. Quantitative results of GC-MS are compared with those obtained by an ultraviolet-visible method. Copyright 2004 American Chemical Society

  16. A Calcium Enterolith in a Patient with Crohn's Disease and Its In Vitro Dissolubility in Citric Acid

    PubMed Central

    Urata, Haruo; Ohmori, Masayasu; Kondo, Yoshitaka; Kawahara, Yoshiro; Okada, Hiroyuki

    2017-01-01

    The microstructure and dissolubility of a calcified enterolith and enterolith pieces removed from a 26-year-old Japanese woman with Crohn's disease were analyzed using scanning electron microscopy and energy dispersive X-ray spectroscopy. The enterolith showed a multilayered structure with fatty acid calcium and magnesium phosphate. The amount of calcium, magnesium, and phosphate decreased after they were immersed in a citric acid solution, suggesting a potential contribution of acidic aqueous solution to elute inorganic substances contained in calcified enteroliths. This is the first study to investigate the in vitro dissolubility of calcified enteroliths induced by citric acid solution. PMID:29082049

  17. Comparison of sodium acid sulfate to citric acid to inhibit browning of fresh-cut potatoes.

    PubMed

    Calder, Beth L; Kash, Emily A; Davis-Dentici, Katherine; Bushway, Alfred A

    2011-04-01

    Sodium acid sulfate (SAS) dip treatments were evaluated against a distilled water control and citric acid (CA) to compare its effectiveness in reducing enzymatic browning of raw, French-fry cut potatoes. Two separate studies were conducted with dip concentrations ranging from 0%, 1%, and 3% in experiment 1 to 0%, 2%, and 2.5% in experiment 2 to determine optimal dip concentrations. Russet Burbank potatoes were peeled, sliced, and dipped for 1 min and stored at 3 °C. Color, texture, fry surface pH, and microbiological analyses were conducted on days 0, 7, and 14. The 3% SAS- and CA-treated samples had significantly (p<0.0001) lower pH levels on fry surfaces than all other treatments. Both acidulants had significantly (p≤0.05) lower aerobic plate counts compared to controls in both studies by day 7. However, SAS appeared to be the most effective at the 3% level in maintaining a light fry color up to day 14 and had the highest L-values than all other treatments. The 3% SAS-treated fry slices appeared to have the least change in textural properties over storage time, having a significantly (p=0.0002) higher force value (kg force [kgf]) than the other treatments during experiment 1, without any signs of case-hardening that appeared in the control and CA-treated samples. SAS was just as comparable to CA in reducing surface fry pH and also lowering microbial counts over storage time. According to the results, SAS may be another viable acidulant to be utilized in the fresh-cut fruit and vegetable industry.

  18. NASA and ESA Collaboration on Alternative to Nitric Acid Passivation: Parameter Optimization of Citric Acid Passivation for Stainless Steel Alloys

    NASA Technical Reports Server (NTRS)

    Kessel, Kurt R.

    2016-01-01

    National Aeronautics and Space Administration (NASA) Headquarters chartered the Technology Evaluation for Environmental Risk Mitigation Principal Center (TEERM) to coordinate agency activities affecting pollution prevention issues identified during system and component acquisition and sustainment processes. The primary objectives of NASA TEERM are to: Reduce or eliminate the use of hazardous materials or hazardous processes at manufacturing, remanufacturing, and sustainment locations. Avoid duplication of effort in actions required to reduce or eliminate hazardous materials through joint center cooperation and technology sharing. Corrosion is an extensive problem that affects the National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA). The damaging effects of corrosion result in steep costs, asset downtime affecting mission readiness, and safety risks to personnel. Consequently, it is vital to reduce corrosion costs and risks in a sustainable manner. NASA and ESA have numerous structures and equipment that are fabricated from stainless steel. The standard practice for protection of stainless steel is a process called passivation. Passivation is defined by The American Heritage Dictionary of the English Language as to treat or coat (a metal) in order to reduce the chemical reactivity of its surface. Passivation works by forming a shielding outer (metal oxide) layer that reduces the impact of destructive environmental factors such as air or water. Consequently, this process necessitates a final product that is very clean and free of iron and other contaminants. Typical passivation procedures call for the use of nitric acid; however, there are a number of environmental, worker safety, and operational issues associated with its use. Citric acid is an alternative to nitric acid for the passivation of stainless steels. Citric acid offers a variety of benefits including increased safety for personnel, reduced environmental impact, and

  19. The Role of Citric Acid in Perfecting Platinum Monolayer on Palladium Nanoparticles during the Surface Limited Redox Replacement Reaction

    SciTech Connect

    Zhu, Shangqian; Yue, Jeffrey; Qin, Xueping

    Cu-mediated-Pt-displacement method that involves the displacement of an underpotentially deposited (UPD) Cu monolayer by Pt has been extensively studied to prepare core-shell catalysts. It has been found that Pt clusters instead of a uniform Pt monolayer were formed in the gram batch synthesis. With a suitable surfactant, such as citric acid, the Pt shell could be much more uniform. In this study, the role of citric acid in controlling the Cu-Pt displacement reaction kinetics was studied by electrochemical techniques and theoretical approaches. It was found that citric acid strongly adsorbed on Pd, Pt, Cu/Pd, and Pt/Pd surfaces, especially in themore » double layer region in acid solutions. The strong adsorption of citric acid slowed down the Cu-Pt displacement reaction. The main characteristics of such strong interaction most likely arises from the OH groups in the citric acid molecule according to the molecular dynamics simulation results.« less

  20. The Role of Citric Acid in Perfecting Platinum Monolayer on Palladium Nanoparticles during the Surface Limited Redox Replacement Reaction

    DOE PAGES

    Zhu, Shangqian; Yue, Jeffrey; Qin, Xueping; ...

    2016-07-28

    Cu-mediated-Pt-displacement method that involves the displacement of an underpotentially deposited (UPD) Cu monolayer by Pt has been extensively studied to prepare core-shell catalysts. It has been found that Pt clusters instead of a uniform Pt monolayer were formed in the gram batch synthesis. With a suitable surfactant, such as citric acid, the Pt shell could be much more uniform. In this study, the role of citric acid in controlling the Cu-Pt displacement reaction kinetics was studied by electrochemical techniques and theoretical approaches. It was found that citric acid strongly adsorbed on Pd, Pt, Cu/Pd, and Pt/Pd surfaces, especially in themore » double layer region in acid solutions. The strong adsorption of citric acid slowed down the Cu-Pt displacement reaction. The main characteristics of such strong interaction most likely arises from the OH groups in the citric acid molecule according to the molecular dynamics simulation results.« less

  1. An autopsy case of death due to metabolic acidosis after citric acid ingestion.

    PubMed

    Ikeda, Tomoya; Usui, Akihito; Matsumura, Takashi; Aramaki, Tomomi; Hosoya, Tadashi; Igari, Yui; Ohuchi, Tsukasa; Hayashizaki, Yoshie; Usui, Kiyotaka; Funayama, Masato

    2015-11-01

    A man in his 40s was found unconscious on a sofa in a communal residence for people with various disabilities. He appeared to have drunk 800 ml of undiluted citric acid from a commercial plastic bottle. The instructions on the label of the beverage specified that the beverage be diluted 20- to 30-fold before consumption. The patient was admitted to an emergency hospital with severe metabolic acidosis (pH, 6.70; HCO3(-), 3.6 mEq/L) and a low ionized calcium level (0.73 mmol/L). Although ionized calcium and catecholamines were continuously administered intravenously to correct the acidosis, the state of acidemia and low blood pressure did not improve, and he died 20 h later. Citric acid concentrations in the patient's serum drawn shortly after treatment in the hospital and from the heart at autopsy were 80.6 mg/ml and 39.8 mg/dl, respectively (normal range: 1.3-2.6 mg/dl). Autopsy revealed black discoloration of the mucosal surface of the esophagus. Microscopically, degenerated epithelium and neutrophilic infiltration in the muscle layer were observed. In daily life, drinking a large amount of concentrated citric acid beverage is rare as a cause of lethal poisoning. However, persons with mental disorders such as dementia may mistakenly drink detergent or concentrated fluids, as in our case. Family members or facility staff in the home or nursing facility must bear in mind that they should not leave such bottles in places where they are easily accessible to mentally handicapped persons. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  2. Mast cell mediators in citric acid-induced airway constriction of guinea pigs

    SciTech Connect

    Lin, C.-H.; Lai, Y.-L.

    2005-08-15

    We demonstrated previously that mast cells play an important role in citric acid (CA)-induced airway constriction. In this study, we further investigated the underlying mediator(s) for this type of airway constriction. At first, to examine effects caused by blocking agents, 67 young Hartley guinea pigs were divided into 7 groups: saline + CA; methysergide (serotonin receptor antagonist) + CA; MK-886 (leukotriene synthesis inhibitor) + CA; mepyramine (histamine H{sub 1} receptor antagonist) + CA; indomethacin (cyclooxygenase inhibitor) + CA; cromolyn sodium (mast cell stabilizer) + CA; and compound 48/80 (mast cell degranulating agent) + CA. Then, we tested whether leukotriene C{submore » 4} (LTC{sub 4}) or histamine enhances CA-induced airway constriction in compound 48/80-pretreated guinea pigs. We measured dynamic respiratory compliance (Crs) and forced expiratory volume in 0.1 s (FEV{sub 0.1}) during either baseline or recovery period. In addition, we detected histamine level, an index of pulmonary mast cell degranulation, in bronchoalveolar lavage (BAL) samples. Citric acid aerosol inhalation caused decreases in Crs and FEV{sub 0.1}, indicating airway constriction in the control group. This airway constriction was significantly attenuated by MK-886, mepyramine, cromolyn sodium, and compound 48/80, but not by either methysergide or indomethacin. Both LTC{sub 4} and histamine infusion significantly increased the magnitude of CA-induced airway constriction in compound 48/80-pretreated guinea pigs. Citric acid inhalation caused significant increase in histamine level in the BAL sample, which was significantly suppressed by compound 48/80. These results suggest that leukotrienes and histamine originating from mast cells play an important role in CA inhalation-induced noncholinergic airway constriction.« less

  3. De novo transcriptome analysis of rose-scented geranium provides insights into the metabolic specificity of terpene and tartaric acid biosynthesis.

    PubMed

    Narnoliya, Lokesh K; Kaushal, Girija; Singh, Sudhir P; Sangwan, Rajender S

    2017-01-13

    Rose-scented geranium (Pelargonium sp.) is a perennial herb that produces a high value essential oil of fragrant significance due to the characteristic compositional blend of rose-oxide and acyclic monoterpenoids in foliage. Recently, the plant has also been shown to produce tartaric acid in leaf tissues. Rose-scented geranium represents top-tier cash crop in terms of economic returns and significance of the plant and plant products. However, there has hardly been any study on its metabolism and functional genomics, nor any genomic expression dataset resource is available in public domain. Therefore, to begin the gains in molecular understanding of specialized metabolic pathways of the plant, de novo sequencing of rose-scented geranium leaf transcriptome, transcript assembly, annotation, expression profiling as well as their validation were carried out. De novo transcriptome analysis resulted a total of 78,943 unique contigs (average length: 623 bp, and N50 length: 752 bp) from 15.44 million high quality raw reads. In silico functional annotation led to the identification of several putative genes representing terpene, ascorbic acid and tartaric acid biosynthetic pathways, hormone metabolism, and transcription factors. Additionally, a total of 6,040 simple sequence repeat (SSR) motifs were identified in 6.8% of the expressed transcripts. The highest frequency of SSR was of tri-nucleotides (50%). Further, transcriptome assembly was validated for randomly selected putative genes by standard PCR-based approach. In silico expression profile of assembled contigs were validated by real-time PCR analysis of selected transcripts. Being the first report on transcriptome analysis of rose-scented geranium the data sets and the leads and directions reflected in this investigation will serve as a foundation for pursuing and understanding molecular aspects of its biology, and specialized metabolic pathways, metabolic engineering, genetic diversity as well as molecular breeding.

  4. Substrates and oxygen dependent citric acid production by Yarrowia lipolytica: insights through transcriptome and fluxome analyses.

    PubMed

    Sabra, Wael; Bommareddy, Rajesh Reddy; Maheshwari, Garima; Papanikolaou, Seraphim; Zeng, An-Ping

    2017-05-08

    Unlike the well-studied backer yeast where catabolite repression represents a burden for mixed substrate fermentation, Yarrowia lipolytica, an oleaginous yeast, is recognized for its potential to produce single cell oils and citric acid from different feedstocks. These versatilities of Y. lipolytica with regards to substrate utilization make it an attractive host for biorefinery application. However, to develop a commercial process for the production of citric acid by Y. lipolytica, it is necessary to better understand the primary metabolism and its regulation, especially for growth on mixed substrate. Controlling the dissolved oxygen concentration (pO 2 ) in Y. lipolytica cultures enhanced citric acid production significantly in cultures grown on glucose in mono- or dual substrate fermentations, whereas with glycerol as mono-substrate no significant effect of pO 2 was found on citrate production. Growth on mixed substrate with glucose and glycerol revealed a relative preference of glycerol utilization by Y. lipolytica. Under optimized conditions with pO 2 control, the citric acid titer on glucose in mono- or in dual substrate cultures was 55 and 50 g/L (with productivity of 0.6 g/L*h in both cultures), respectively, compared to a maximum of 18 g/L (0.2 g/L*h) with glycerol in monosubstrate culture. Additionally, in dual substrate fermentation, glycerol limitation was found to trigger citrate consumption despite the presence of enough glucose in pO 2 -limited culture. The metabolic behavior of this yeast on different substrates was investigated at transcriptomic and 13 C-based fluxomics levels. Upregulation of most of the genes of the pentose phosphate pathway was found in cultures with highest citrate production with glucose in mono- or in dual substrate fermentation with pO 2 control. The activation of the glyoxylate cycle in the oxygen limited cultures and the imbalance caused by glycerol limitation might be the reason for the re-consumption of citrate in

  5. Influence of concentration, time and method of application of citric acid and sodium citrate in root conditioning

    PubMed Central

    CAVASSIM, Rodrigo; LEITE, Fábio Renato Manzolli; ZANDIM, Daniela Leal; DANTAS, Andrea Abi Rached; RACHED, Ricardo Samih Georges Abi; SAMPAIO, José Eduardo Cezar

    2012-01-01

    Objective The aim of this study was to establish the parameters of concentration, time and mode of application of citric acid and sodium citrate in relation to root conditioning. Material and Methods A total of 495 samples were obtained and equally distributed among 11 groups (5 for testing different concentrations of citric acid, 5 for testing different concentrations of sodium citrate and 1 control group). After laboratorial processing, the samples were analyzed under scanning electron microscopy. A previously calibrated and blind examiner evaluated micrographs of the samples. Non-parametric statistical analysis was performed to analyze the data obtained. Results Brushing 25% citric acid for 3 min, promoted greater exposure of collagen fibers in comparison with the brushing of 1% citric acid for 1 minute and its topical application at 1% for 3 min. Sodium citrate exposed collagen fibers in a few number of samples. Conclusion Despite the lack of statistical significance, better results for collagen exposure were obtained with brushing application of 25% citric acid for 3 min than with other application parameter. Sodium citrate produced a few number of samples with collagen exposure, so it is not indicated for root conditioning. PMID:22858707

  6. Fabrication of calcium phosphate–calcium sulfate injectable bone substitute using hydroxy-propyl-methyl-cellulose and citric acid

    PubMed Central

    Thai, Van Viet

    2010-01-01

    In this study, an injectable bone substitute (IBS) consisting of citric acid, chitosan, and hydroxyl propyl methyl cellulose (HPMC) as the liquid phase and tetra calcium phosphate (TTCP), dicalcium phosphate dihydrate (DCPD) and calcium sulfate dehydrate (CSD, CaSO4·2H2O) powders as the solid phase, were fabricated. Two groups were classified based on the percent of citric acid in the liquid phase (20, 40 wt%). In each groups, the HPMC percentage was 0, 2, and 4 wt%. An increase in compressive strength due to changes in morphology was confirmed by scanning electron microscopy images. A good conversion rate of HAp at 20% citric acid was observed in the XRD profiles. In addition, HPMC was not obviously affected by apatite formation. However, both HPMC and citric acid increased the compressive strength of IBS. The maximum compressive strength for IBS was with 40% citric acid and 4% HPMC after 14 days of incubation in 100% humidity at 37°C. PMID:20333539

  7. Removal of heavy metals from polluted soil using the citric acid fermentation broth: a promising washing agent.

    PubMed

    Zhang, Hongjiao; Gao, Yuntao; Xiong, Huabin

    2017-04-01

    The citric acid fermentation broth was prepared and it was employed to washing remediation of heavy metal-polluted soil. A well-defined washing effect was obtained, the removal percentages using citric acid fermentation broth are that 48.2% for Pb, 30.6% for Cu, 43.7% for Cr, and 58.4% for Cd and higher than that using citric acid solution. The kinetics of heavy metals desorption can be described by the double constant equation and Elovich equation and is a heterogeneous diffusion process. The speciation analysis shows that the citric acid fermentation broth can effectively reduce bioavailability and environmental risk of heavy metals. Spectroscopy characteristics analysis suggests that the washing method has only a small effect on the mineral composition and does not destroy the framework of soil system. Therefore, the citric acid fermentation broth is a promising washing agent and possesses a potential practical application value in the field of remediation of soils with a good washing performance.

  8. Antilisterial activity and consumer acceptance of irradiated chicken breast meat vacuum-infused with grape seed and green tea extracts and tartaric acid.

    PubMed

    Over, K F; Hettiarachchy, N S; Perumalla, A V S; Johnson, M G; Meullenet, J-F; Dickson, J S; Holtzbauer, M J; Niebuhr, S E; Davis, B

    2010-09-01

    Contamination of poultry with pathogenic bacteria contributes to human foodborne disease, causes damage to industry brand names, and has a significant economic impact on the food industry in the form of both damage to industry brand names and losses associated with recalls. Irradiation is a safe and effective means of decontaminating poultry products, but the maximum dose strengths allowed negatively impact poultry sensory quality characteristics. The 1st objective of this study was to investigate the potential interactive inhibitory effects of natural antimicrobials as components of a vacuum-marination in addition to various dose levels of irradiation. Tartaric acid (TA) at 2 levels and grape seed (GS) and green tea (GT) extracts were combined, vacuum-infused into chicken breast fillets, and irradiated at 1, 2, and 3 kGy by electron beam irradiation. The 2nd objective was to use a consumer test group to evaluate TA and plant extract infusion into chicken breast fillets with and without irradiation at 2 kGy on overall impression, flavor, texture, appearance, and tenderness. The results showed that samples vacuum-infused with TA at 37.5 and 75.0 mM and irradiated at 1 kGy significantly reduced Listeria monocytogenes (L.m.) levels by 2 and 3 log CFU/g compared to the control after 12 d of refrigerated storage. Vacuum-infusion of TA at 37.5 and 75.0 mM at 2 and 3 kGy irradiation, reduced L.m. to near nondetectable levels. The addition of TA and GS and GT to chicken breast fillets with and without irradiation did not significantly impact consumer preference, tenderness, appearance, or flavor. The addition of tartaric acid and natural plant extracts to chicken marinades could contribute to the prevention of L.m. contamination.

  9. Synergistic antimicrobial activity of caprylic acid in combination with citric acid against both Escherichia coli O157:H7 and indigenous microflora in carrot juice.

    PubMed

    Kim, S A; Rhee, M S

    2015-08-01

    The identification of novel, effective, and non-thermal decontamination methods is imperative for the preservation of unpasteurized and fresh vegetable juices. The aim of this study was to examine the bactericidal effects of caprylic acid + citric acid against the virulent pathogen Escherichia coli O157:H7 and the endogenous microflora in unpasteurized fresh carrot juice. Carrot juice was treated with either caprylic acid, citric acid, or a combination of caprylic acid + citric acid at mild heating temperature (45 °C or 50 °C). The color of the treated carrot juice as well as microbial survival was examined over time. Combined treatment was more effective than individual treatment in terms of both color and microbial survival. Caprylic acid + citric acid treatment (each at 5.0 mM) at 50 °C for 5 min resulted in 7.46 and 3.07 log CFU/ml reductions in the E. coli O157:H7 and endogenous microflora populations, respectively. By contrast, there was no apparent reduction in either population following individual treatment. A validation assay using a low-density E. coli O157:H7 inoculum (3.31 log CFU/ml) showed that combined treatment with caprylic acid (5.0 mM) + citric acid (2.5 mM) at 50 °C for >5 min or with caprylic acid + citric acid (both at 5.0 mM) at either 45 °C or 50 °C for >5 min completely destroyed the bacteria. Combined treatment also increased the redness of the juice, which is a perceived indication of quality. Taken together, these results indicate that combined treatment with low concentrations of caprylic acid and citric acid, which are of biotic origin, can eliminate microorganisms from unpasteurized carrot juice. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Nutritional quality assessment of tomato fruits after exposure to uncoated and citric acid coated cerium oxide nanoparticles, bulk cerium oxide, cerium acetate and citric acid.

    PubMed

    Barrios, Ana Cecilia; Medina-Velo, Illya A; Zuverza-Mena, Nubia; Dominguez, Osvaldo E; Peralta-Videa, Jose R; Gardea-Torresdey, Jorge L

    2017-01-01

    Little is known about the effects of surface modification on the interaction of nanoparticles (NPs) with plants. Tomato (Solanum lycopersicum L.) plants were cultivated in potting soil amended with bare and citric acid coated nanoceria (nCeO 2, nCeO 2 +CA), cerium acetate (CeAc), bulk cerium oxide (bCeO 2 ) and citric acid (CA) at 0-500 mg kg -1 . Fruits were collected year-round until the harvesting time (210 days). Results showed that nCeO 2 +CA at 62.5, 250 and 500 mg kg -1 reduced dry weight by 54, 57, and 64% and total sugar by 84, 78, and 81%. At 62.5, 125, and 500 mg kg -1 nCeO 2 +CA decreased reducing sugar by 63, 75, and 52%, respectively and at 125 mg kg -1 reduced starch by 78%, compared to control. The bCeO 2 at 250 and 500 mg kg -1 , increased reducing sugar by 67 and 58%. In addition, when compared to controls, nCeO 2 at 500 mg kg -1 reduced B (28%), Fe (78%), Mn (33%), and Ca (59%). At 125 mg kg -1 decreased Al by 24%; while nCeO 2 +CA at 125 and 500 mg kg -1 increased B by 33%. On the other hand, bCeO 2 at 62.5 mg kg -1 increased Ca (267%), but at 250 mg kg -1 reduced Cu (52%), Mn (33%), and Mg (58%). Fruit macromolecules were mainly affected by nCeO 2 +CA, while nutritional elements by nCeO 2 ; however, all Ce treatments altered, in some way, the nutritional quality of tomato fruit. To our knowledge, this is the first study comparing effects of uncoated and coated nanoceria on tomato fruit quality. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  11. Effects of heat/citric acid reprocessing on high-flux polysulfone dialyzers.

    PubMed

    Cornelius, Rena M; McClung, W Glenn; Richardson, Robert M A; Estridge, Charles; Plaskos, Nicholas; Yip, Christopher M; Brash, John L

    2002-01-01

    The surface features, morphology, and tensile properties of fibers obtained from pristine, reprocessed, and reused Fresenius Polysulfone High-Flux (Hemoflow F80A) hemodialyzers have been studied. Scanning electron microscopy of the dialyzer fibers revealed a dense skin layer on the inner surface of the membrane and a relatively thick porous layer on the outer surface. Transmission electron microscopy and atomic force microscopy showed an alteration in membrane morphology due to reprocessing and reuse, or to a deposition of blood-borne material on the membrane that is not removed with reprocessing. Fluorescent microscopy images also showed that a fluorescent material not removed by heat/citric acid reprocessing builds up with continued use of the dialyzers. The tensile properties of the dialyzer fibers were not affected by the heat/citric acid reprocessing procedure. The protein layers formed on pristine and reused hemodialyzer membranes during clinical use were also studied using sodium dodecyl sulfate polyacrylamide gel electrophoresis and immunoblotting. A considerable amount of protein was found on the blood side of single and multiple use dialyzers. Proteins adsorbed on the dialysate side of the membrane were predominantly in the molecular weight region below 30 kDa. Little protein was detected on the membranes of reprocessed hemodialyzers.

  12. Citric acid modified kenaf core fibres for removal of methylene blue from aqueous solution.

    PubMed

    Sajab, Mohd Shaiful; Chia, Chin Hua; Zakaria, Sarani; Jani, Saad Mohd; Ayob, Mohd Khan; Chee, Kah Leong; Khiew, Poi Sim; Chiu, Wee Siong

    2011-08-01

    Chemically modified kenaf core fibres were prepared via esterification in the presence of citric acid (CA). The adsorption kinetics and isotherm studies were carried out under different conditions to examine the adsorption efficiency of CA-treated kenaf core fibres towards methylene blue (MB). The adsorption capacity of the kenaf core fibres increased significantly after the citric acid treatment. The values of the correlation coefficients indicated that the Langmuir isotherm fitted the experimental data better than the Freundlich isotherm. The maximum adsorption capacity of the CA-treated kenaf core fibres was found to be 131.6mg/g at 60°C. Kinetic models, pseudo-first-order, pseudo-second-order and intraparticle diffusion, were employed to describe the adsorption mechanism. The kinetic data were found to fit pseudo-second-order model equation as compared to pseudo-first-order model. The adsorption of MB onto the CA-treated kenaf core fibres was spontaneous and endothermic. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. Response of the periapical tissue of dogs' teeth to the action of citric acid and EDTA.

    PubMed

    Sperandio, Cristina Berthold; Silveira, Luiz Fernando Machado; de Araújo, Lenita Aver; Martos, Josué; Malshe, Ashwin

    2008-01-01

    The purpose of this study was to analyze the inflammatory response of dog's periapical tissues to 17% trisodium EDTA salt (pH 8.0) and 1% citric acid (pH 2.0). Saline was used as a control. Six adult dogs were used as the biological model of the study. The experimental units comprised 56 roots of mandibular molars (first and second) and premolars (first, second and third). After coronal opening, pulpectomy and root canal instrumentation were performed using the above-mentioned irrigating solutions. After 24 and 48 hours, the animals were euthanized and the teeth and their supporting tissues were removed and histologically processed. The sections were stained with hematoxylin and eosin and analyzed histopathologically with a light microscope at x100 magnification. The histological analysis focused on the occurrence of acute inflammatory response. The presence of swelling, vasodilatation and inflammatory cells were evaluated and the degree of inflammation was determined for each case. Data were analyzed by Fisher's exact test using the SPSS software with a confidence interval of 95% (p<0.05). 17% EDTA and 1% citric acid caused inflammatory responses in dog's periapical tissues with no significant differences to each other or to saline (control) at either the 24-hour (p=0.482) or 48-hour (p=0.377) periods. It may be concluded that the inflammatory response was of mild intensity for the tested substances.

  14. RESPONSE OF THE PERIAPICAL TISSUE OF DOGS' TEETH TO THE ACTION OF CITRIC ACID AND EDTA

    PubMed Central

    Sperandio, Cristina Berthold; Silveira, Luiz Fernando Machado; de Araújo, Lenita Aver; Mertos, Josué; Malshe, Ashwin

    2008-01-01

    The purpose of this study was to analyze the inflammatory response of dog's periapical tissues to 17% trisodium EDTA salt (pH 8.0) and 1% citric acid (pH 2.0). Saline was used as a control. Six adult dogs were used as the biological model of the study. The experimental units comprised 56 roots of mandibular molars (first and second) and premolars (first, second and third). After coronal opening, pulpectomy and root canal instrumentation were performed using the above-mentioned irrigating solutions. After 24 and 48 hours, the animals were euthanized and the teeth and their supporting tissues were removed and histologically processed. The sections were stained with hematoxylin and eosin and analyzed histopathologically with a light microscope at x100 magnification. The histological analysis focused on the occurrence of acute inflammatory response. The presence of swelling, vasodilatation and inflammatory cells were evaluated and the degree of inflammation was determined for each case. Data were analyzed by Fisher's exact test using the SPSS software with a confidence interval of 95% (p<0.05). 17% EDTA and 1% citric acid caused inflammatory responses in dog's periapical tissues with no significant differences to each other or to saline (control) at either the 24-hour (p=0.482) or 48-hour (p=0.377) periods. It may be concluded that the inflammatory response was of mild intensity for the tested substances. PMID:19089291

  15. Preliminary study on preparation of BCNO phosphor particles using citric acid as carbon source

    SciTech Connect

    Nuryadin, Bebeh W.; Pratiwi, Tripuspita; Faryuni, Irfana D.

    A citric acid was used as a carbon source in the preparation of boron carbon oxy-nitride (BCNO) phosphor particles by a facile process. The preparation process was conducted at relatively low temperature 750 °C and at ambient pressure. The prepared BCNO phosphors showed a high photoluminescence (PL) performance at peak emission wavelength of 470 nm under excitation by a UV light 365 nm. The effects of carbon/boron and nitrogen/boron molar ratios on the PL properties were also investigated. The result showed that the emission spectra with a wavelength peak ranging from 444 nm to 496 nm can be obtained bymore » varying carbon/boron ratios from 0.1 to 0.9. In addition, the observations showed that the BCNO phosphor material has two excitation peaks located at the 365 nm (UV) and 420 nm (blue). Based on these observations, we believe that the citric acid derived BCNO phosphor particles can be a promising inexpensive material for phosphor conversion-based white LED.« less

  16. Enhanced biocompatibility and antibacterial property of polyurethane materials modified with citric acid and chitosan.

    PubMed

    Liu, Tian-Ming; Wu, Xing-Ze; Qiu, Yun-Ren

    2016-08-01

    Citric acid (CA) and chitosan (CS) were covalently immobilized on polyurethane (PU) materials to improve the biocompatibility and antibacterial property. The polyurethane pre-polymer with isocyanate group was synthesized by one pot method, and then grafted with citric acid, followed by blending with polyethersulfone (PES) to prepare the blend membrane by phase-inversion method so that chitosan can be grafted from the membrane via esterification and acylation reactions eventually. The native and modified membranes were characterized by attenuated total reflectance-Fourier transform infrared spectroscope, X-ray photoelectron spectroscopy, scanning electron microscopy, water contact angle measurement, and tensile strength test. Protein adsorption, platelet adhesion, hemolysis assay, activated partial thromboplastin time, prothrombin time, thrombin time, and adsorption of Ca(2+) were executed to evaluate the blood compatibility of the membranes decorated by CA and CS. Particularly, the antibacterial activities on the modified membranes were evaluated based on a vitro antibacterial test. It could be concluded that the modified membrane had good anticoagulant property and antibacterial property.

  17. Validation of the ERS standard citric acid cough challenge in healthy adult volunteers

    PubMed Central

    2010-01-01

    Protocols measuring cough sensitivity can vary in terms of nebuliser, tussive agent, single and dose response. A definitive method for measuring cough sensitivity needs to be established. The ERS guidelines recommend the KoKo DigiDoser (KD) delivery system. Study aim, was to compare the reproducibility of this citric acid (CA) cough challenge and previously established Mefar dosimeter (MD) protocol. 39 (female 26) volunteers mean age (40.4 yrs) were randomised to either KD or MD. Intra-day and inter-day reproducibility was compared. We calculated the concentration of citric acid evoking 2 coughs (C2). The geometric mean C2 (95%CI) was similar for both KD and MD, of 263 (200,339) mM and 209 (151,288) mM respectively. The mean KD C2 was not significantly different. (F = 0.807, p = 0.93) from baseline over 1, 2, and 4 hrs however, the MD demonstrated significant variability (F = 7.85, P < 0.001) Measuring mean log C2 at baseline and at 2 weeks, the KD demonstrated a stronger intraclass correlation of log C2 at baseline with 2 week log C2, ICC = 0.70 than was shown with the Mefar, ICC = 0.41 Administering CA from KD offers a reproducible cough challenge in healthy volunteers. The results correlate well with the MD challenge but offer greater intra-day and inter-day reproducibility. Trial Registration Current controlled trials ISRCTN98385033 PMID:20698995

  18. Accelerated anaerobic dechlorination of DDT in slurry with Hydragric Acrisols using citric acid and anthraquinone-2,6-disulfonate (AQDS).

    PubMed

    Liu, Cuiying; Xu, Xianghua; Fan, Jianling

    2015-12-01

    The application of electron donor and electron shuttle substances has a vital influence on electron transfer, thus may affect the reductive dechlorination of 1,1,1-trichoro-2,2-bis(p-chlorophenyl)ethane (DDT) in anaerobic reaction systems. To evaluate the roles of citric acid and anthraquinone-2,6-disulfonate (AQDS) in accelerating the reductive dechlorination of DDT in Hydragric Acrisols that contain abundant iron oxide, a batch anaerobic incubation experiment was conducted in a slurry system with four treatments of (1) control, (2) citric acid, (3) AQDS, and (4) citric acid+AQDS. Results showed that DDT residues decreased by 78.93%-92.11% of the initial quantities after 20days of incubation, and 1,1-dichloro-2,2-bis(4-chlorophenyl)-ethane (DDD) was the dominant metabolite. The application of citric acid accelerated DDT dechlorination slightly in the first 8days, while the methanogenesis rate increased quickly, and then the acceleration effect improved after the 8th day while the methanogenesis rate decreased. The amendment by AQDS decreased the Eh value of the reaction system and accelerated microbial reduction of Fe(III) oxides to generate Fe(II), which was an efficient electron donor, thus enhancing the reductive dechlorination rate of DDT. The addition of citric acid+AQDS was most efficient in stimulating DDT dechlorination, but no significant interaction between citric acid and AQDS on DDT dechlorination was observed. The results will be of great significance for developing an efficient in situ remediation strategy for DDT-contaminated sites. Copyright © 2015. Published by Elsevier B.V.

  19. [Effects of low molecular weight organic acids on speciation of exogenous Cu in an acid soil].

    PubMed

    Huang, Guo-Yong; Fu, Qing-Ling; Zhu, Jun; Wan, Tian-Ying; Hu, Hong-Qing

    2014-08-01

    In order to ascertain the effect of LMWOA (citric acid, tartaric acid, oxalic acid) on Cu-contaminated soils and to investigate the change of Cu species, a red soil derived from quartz sandstone deposit was added by Cu (copper) in the form of CuSO4 x 5H2O so as to simulate soil Cu pollution, keeping the additional Cu concentrations were 0, 100, 200, 400 mg x kg(-1) respectively. After 9 months, different LMWOA was also added into the simulated soil, keeping the additional LMWOAs in soil were 0, 5, 10, 20 mmol x kg(-1) respectively. After 2 weeks incubation, the modified sequential extraction method on BCR (European Communities Bureau of Reference) was used to evaluate the effects of these LMWOAs on the changes of copper forms in soil. The result showed that the percentage of weak acid dissolved Cu, the most effective form in the soil increased with three organic acids increase in quantity in the simulated polluted soil. And there was a good activation effect on Cu in the soil when organic acid added. Activation effects on Cu increased with concentration of citric acid increasing, but it showed a rise trend before they are basically remained unchanged in the case of tartaric acid and oxalic acid added in the soil. On the contrary, the state of the reduction of copper which was regarded as a complement for effective state decreased with the increased concentration of organic acid in the soil, especially with citric acid. When 20 mmol x kg(-1) oxalic acid and citric acid were added into the soil, the activation effect was the best; whereas for tartaric, the concentration was 10 mmol x kg(-1). In general, the effect on the changes of Cu forms in the soil is citric acid > tartaric acid > oxalic acid.

  20. Comparison between different types of carboxylmethylcellulose and other oenological additives used for white wine tartaric stabilization.

    PubMed

    Guise, R; Filipe-Ribeiro, L; Nascimento, D; Bessa, O; Nunes, F M; Cosme, F

    2014-08-01

    Carboxylmethylcellulose (CMC) is authorised to prevent wine tartaric instability. The effect of CMC structural characteristics on their effectiveness is not well understood. The main purpose of this study was to compare the impact of CMC's with different degrees of substitution and molecular weight, on tartaric stability, tartaric acid, mineral concentration, phenolic compounds, chromatic and sensory characteristics in white wines, and compare its effectiveness with other oenological additives. Mini-contact test showed that all CMC's and metatartaric acid stabilized the wines; however, some arabic gums and mannoproteins do not stabilized the wines. CMC's had no significant effect on tartaric acid, potassium, calcium and sensory attributes. Tartaric stabilization effectiveness depends on CMC's degree of substitution, but also on wine matrix, probably its initial potassium content. Results suggest that CMC is a good alternative to white wine tartaric stabilization; nevertheless deeper structure knowledge is necessary in order to choose the appropriate CMC for a given tartaric instability. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Linked cycles of oxidative decarboxylation of glyoxylate as protometabolic analogs of the citric acid cycle.

    PubMed

    Springsteen, Greg; Yerabolu, Jayasudhan Reddy; Nelson, Julia; Rhea, Chandler Joel; Krishnamurthy, Ramanarayanan

    2018-01-08

    The development of metabolic approaches towards understanding the origins of life, which have focused mainly on the citric acid (TCA) cycle, have languished-primarily due to a lack of experimentally demonstrable and sustainable cycle(s) of reactions. We show here the existence of a protometabolic analog of the TCA involving two linked cycles, which convert glyoxylate into CO 2 and produce aspartic acid in the presence of ammonia. The reactions proceed from either pyruvate, oxaloacetate or malonate in the presence of glyoxylate as the carbon source and hydrogen peroxide as the oxidant under neutral aqueous conditions and at mild temperatures. The reaction pathway demonstrates turnover under controlled conditions. These results indicate that simpler versions of metabolic cycles could have emerged under potential prebiotic conditions, laying the foundation for the appearance of more sophisticated metabolic pathways once control by (polymeric) catalysts became available.

  2. The Role of Citric Acid in the Stabilization of Nanoparticles and Colloidal Particles in the Environment: Measurement of Surface Forces between Hafnium Oxide Surfaces in the Presence of Citric Acid.

    PubMed

    Shinohara, Shuhei; Eom, Namsoon; Teh, E-Jen; Tamada, Kaoru; Parsons, Drew; Craig, Vincent S J

    2018-02-27

    The interactions between colloidal particles and nanoparticles determine solution stability and the structures formed when the particles are unstable to flocculation. Therefore, knowledge of the interparticle interactions is important for understanding the transport, dissolution, and fate of particles in the environment. The interactions between particles are governed by the surface properties of the particles, which are altered when species adsorb to the surface. The important interactions in the environment are almost never those between the bare particles but rather those between particles that have been modified by the adsorption of natural organic materials. Citric acid is important in this regard not only because it is present in soil but also as a model of humic and fulvic acids. Here we have studied the surface forces between the model metal oxide surface hafnia in the presence of citric acid in order to understand the stability of colloidal particles and nanoparticles. We find that citric acid stabilizes the particles over a wide range of pH at low to moderate ionic strength. At high ionic strength, colloidal particles will flocculate due to a secondary minimum, resulting in aggregates that are dense and easily redispersed. In contrast, nanoparticles stabilized by citric acid remain stable at high ionic strengths and therefore exist in solution as individual particles; this will contribute to their dispersion in the environment and the uptake of nanoparticles by mammalian cells.

  3. Influence of citric acid on the surface texture of glass ionomer restorative materials.

    PubMed

    Reddy, Dappili Swami Ranga; Kumar, Ramachandran Anil; Venkatesan, Sokkalingam Mothilal; Narayan, Gopal Shankar; Duraivel, Dasarathan; Indra, Rajamani

    2014-09-01

    This study determined the effectiveness of G-coat plus surface protective agent over petroleum jelly on the surface texture of conventional Glass ionomer restorative materials. Three chemically cured conventional glass ionomer restorative materials type II, type IX and ketac molar were evaluated in this study. Sixty specimens were made for each restorative material. They were divided into two groups of thirty specimens each. Of the sixty specimens, thirty were coated with G-coat plus (a nano-filler coating) and the rest with petroleum jelly. Thirty samples of both protective coating agents were randomly divided into six groups of five specimens and conditioned in citric acid solutions of differing pH (pH 2, 3, 4, 5, 6 & 7). Each specimen was kept in citric acid for three hours a day, and the rest of time stored in salivary substitute. This procedure was repeated for 8 days. After conditioning, the surface roughness (Ra, μm) of each specimen was measured using a surface profilometer (Taylor & Habson, UK). Data was analyzed using one-way analysis of variance (ANOVA) and Tukey's HSD test at a significance level of 0.05. The surface textures of all the tested glass ionomer restorative materials protected with G-coat plus were not significantly affected by acids at low pH. The surface textures of all the tested glass ionomer restorative materials protected with petroleum jelly coating were significantly affected by acids at low pH. The effects of pH on the surface texture of glass ionomer restoratives are material dependent. Among all the materials tested the surface texture of Type II GIC (Group I) revealed marked deterioration when conditioned in solutions of low pH and was statistically significant. Hence, a protective coating either with G-coat plus or with light polymerized low viscosity unfilled resin adhesives is mandatory for all the glass ionomer restorations to increase the wear resistance of the restorative materials.

  4. Production of succinic Acid from citric Acid and related acids by lactobacillus strains.

    PubMed

    Kaneuchi, C; Seki, M; Komagata, K

    1988-12-01

    A number of Lactobacillus strains produced succinic acid in de Man-Rogosa-Sharpe broth to various extents. Among 86 fresh isolates from fermented cane molasses in Thailand, 30 strains (35%) produced succinic acid; namely, 23 of 39 Lactobacillus reuteri strains, 6 of 18 L. cellobiosus strains, and 1 of 6 unidentified strains. All of 10 L. casei subsp. casei strains, 5 L. casei subsp. rhamnosus strains, 6 L. mali strains, and 2 L. buchneri strains did not produce succinic acid. Among 58 known strains including 48 type strains of different Lactobacillus species, the strains of L. acidophilus, L. crispatus, L. jensenii, and L. parvus produced succinic acid to the same extent as the most active fresh isolates, and those of L. alimentarius, L. collinoides, L. farciminis, L. fructivorans (1 of 2 strains tested), L. malefermentans, and L. reuteri were also positive, to lesser extents. Diammonium citrate in de Man-Rogosa-Sharpe broth was determined as a precursor of the succinic acid produced. Production rates were about 70% on a molar basis with two fresh strains tested. Succinic acid was also produced from fumaric and malic acids but not from dl-isocitric, alpha-ketoglutaric, and pyruvic acids. The present study is considered to provide the first evidence on the production of succinic acid, an important flavoring substance in dairy products and fermented beverages, from citrate by lactobacilli.

  5. Production of Succinic Acid from Citric Acid and Related Acids by Lactobacillus Strains

    PubMed Central

    Kaneuchi, Choji; Seki, Masako; Komagata, Kazuo

    1988-01-01

    A number of Lactobacillus strains produced succinic acid in de Man-Rogosa-Sharpe broth to various extents. Among 86 fresh isolates from fermented cane molasses in Thailand, 30 strains (35%) produced succinic acid; namely, 23 of 39 Lactobacillus reuteri strains, 6 of 18 L. cellobiosus strains, and 1 of 6 unidentified strains. All of 10 L. casei subsp. casei strains, 5 L. casei subsp. rhamnosus strains, 6 L. mali strains, and 2 L. buchneri strains did not produce succinic acid. Among 58 known strains including 48 type strains of different Lactobacillus species, the strains of L. acidophilus, L. crispatus, L. jensenii, and L. parvus produced succinic acid to the same extent as the most active fresh isolates, and those of L. alimentarius, L. collinoides, L. farciminis, L. fructivorans (1 of 2 strains tested), L. malefermentans, and L. reuteri were also positive, to lesser extents. Diammonium citrate in de Man-Rogosa-Sharpe broth was determined as a precursor of the succinic acid produced. Production rates were about 70% on a molar basis with two fresh strains tested. Succinic acid was also produced from fumaric and malic acids but not from dl-isocitric, α-ketoglutaric, and pyruvic acids. The present study is considered to provide the first evidence on the production of succinic acid, an important flavoring substance in dairy products and fermented beverages, from citrate by lactobacilli. PMID:16347795

  6. [Effects of Citric Acid on Activation and Methylation of Mercury in the Soils of Water-Level-Fluctuating Zone of the Three Gorges.Reservoir].

    PubMed

    Qin, Cai-qing; Liang, Li; You, Rui; Deng, Han; Wang, Ding-yong

    2015-12-01

    To investigate effects of the main component of vegetation root exudates-citric acid on activation and methylation of mercury in the soil of water-level-fluctuating zone (WLFZ) of the Three Gorges Reservoir area, simulation experiments were conducted by extracting and cultivating soil with different concentrations of citric acid. The results showed that after adding citric acid, the total mercury content in leaching solution before reaching peak were higher than that of the control, and increased with the increase of citric acid concentrations. The maximum amount of mercury complexes increased initially and then reached plateaus with the percentage against the total mercury in soil of 1.03%, 1.67%, 1.99%, 2.47%, 2.68%, 2.73% and 2.73% for different citric acid concentrations (0, 1, 2, 4, 5, 6 and 8 mmol · L⁻¹). In addition, concentrations of methylmercury ( MeHg) in soil remained stable in the first 3 hours, and then increased accompanying with the increasing rate rising with the concentration of citric acid ( besides the control group) . This result indicated that citric acid probably could promote the transformation process from inorganic mercury to MeHg in soil. which increased with the concentration of citric acid.

  7. Phytotoxicity of citric acid and Tween® 80 for potential use as soil amendments in enhanced phytoremediation.

    PubMed

    Agnello, A C; Huguenot, D; van Hullebusch, E D; Esposito, G

    2015-01-01

    Enhanced phytoremediation adding biodegradable amendments like low molecular weight organic acids and surfactants is an interesting area of current research to overcome the limitation that represents low bioavailability of pollutants in soils. However, prior to their use in assisted phytoremediation, it is necessary to test if amendments per se exert any toxic effect to plants and to optimize their application mode. In this context, the present study assessed the effects of citric acid and Tween® 80 (polyethylene glycol sorbitan monooleate) on the development of alfalfa (Medicago sativa) plants, as influenced by their concentration and frequency of application, in order to evaluate the feasibility for their future use in enhanced phytoremediation of multi-contaminated soils. The results showed that citric acid negatively affected plant germination, while it did not have any significant effect on biomass or chlorophyll content. In turn, Tween® 80 did not affect plant germination and showed a trend to increase biomass, as well as it did not have any significant effect on chlorophyll levels. M. sativa appeared to tolerate citric acid and Tween® 80 at the tested concentrations, applied weekly. Consequently, citric acid and Tween® 80 could potentially be utilized to assist phytoremediation of contaminated soils vegetated with M. sativa.

  8. Development of anti-scale poly(aspartic acid-citric acid) dual polymer systems for water treatment.

    PubMed

    Nayunigari, Mithil Kumar; Gupta, Sanjay Kumar; Kokkarachedu, Varaprasad; Kanny, K; Bux, F

    2014-01-01

    The formation of calcium sulphate and calcium carbonate scale poses major problems in heat exchangers and water cooling systems, thereby affecting the performance of these types of equipment. In order to inhibit these scale formations, new types of biodegradable water soluble single polymer and dual poly(aspartic acid-citric acid) polymers were developed and tested. The effectiveness of single polymer and four different compositions of poly aspartic acid and citric acid dual polymer systems as scale inhibitors were evaluated. Details of the synthesis, thermal stability, scale inhibition and the morphological characterization of single and dual polymers are presented in this scientific paper. It was found that the calcium sulphate scale inhibition rate was in the range 76.06-91.45%, while the calcium carbonate scale inhibition rate observed was in the range 23.37-30.0% at 65-70 °C. The finding suggests that the water soluble dual polymers are very effective in sulphate scale inhibition in comparison of calcium carbonate scale inhibition.

  9. Fuzzy approach for improved recognition of citric acid induced piglet coughing from continuous registration

    NASA Astrophysics Data System (ADS)

    Van Hirtum, A.; Berckmans, D.

    2003-09-01

    A natural acoustic indicator of animal welfare is the appearance (or absence) of coughing in the animal habitat. A sound-database of 5319 individual sounds including 2034 coughs was collected on six healthy piglets containing both animal vocalizations and background noises. Each of the test animals was repeatedly placed in a laboratory installation where coughing was induced by nebulization of citric acid. A two-class classification into 'cough' or 'other' was performed by the application of a distance function to a fast Fourier spectral sound analysis. This resulted in a positive cough recognition of 92%. For the whole sound-database however there was a misclassification of 21%. As spectral information up to 10000 Hz is available, an improved overall classification on the same database is obtained by applying the distance function to nine frequency ranges and combining the achieved distance-values in fuzzy rules. For each frequency range clustering threshold is determined by fuzzy c-means clustering.

  10. CaSO4 Scale Formation on Vibrated Piping System in the Presence Citric Acid

    NASA Astrophysics Data System (ADS)

    Mangestiyono, W.; Jamari, J.; Muryanto, S.; Bayuseno, A. P.

    2018-02-01

    Vibration in many industries commonly generated by the operation mechanical equipment such as extruder, mixer, blower, compressor, turbine, generator etc. Vibration propagates into the floor and attacks the pipe around those mechanical equipment. In this paper, the influence of vibration in a pipe on the CaSO4 scale formation was investigated to understand the effect of vibration on the kinetics, mass of scale, crystal phases and crystal polymorph. To generate vibration force, mechanical equipment was prepared consisted of electrical motor, crankshaft, connecting rod and a vibration table at where test pipe section mounted. Deposition rate increased significantly when the vibration affected to the system i.e. 0.5997 and 1.6705 gr/hr for vibration frequency 4.00 and 8.00 Hz. The addition 10.00 ppm of citric acid declined the deposition rate of 8 Hz experiment from 3.4599 gr/hr to 2.2865 gr/hr.

  11. Effects of Polyethylene Glycol and Citric Acid on Preparation and Hydrodechlorination Activity of Molybdenum Phosphide

    NASA Astrophysics Data System (ADS)

    Liu, Xiaomeng; Lu, Shaoxiang; Xu, Hanghui; Ren, Lili

    2018-07-01

    Molybdenum phosphide (MoP), modified by polyethylene glycol (PEG) and citric acid (CA), exhibited 2 to 3 times superior activity than the MoP modified by CA alone. And the optimal activity temperature was reduced from 500 to 450oC. The catalyst was fully characterized by a variety of techniques including X-ray diffraction (XRD), N2 adsorption-desorption isotherm, scanning electron microscopy (SEM), transmission electron microscopy (TEM). The results showed that the addition of PEG and CA increased the surface area of MoP and decreased the particle size of MoP. Furthermore, the reaction mechanism also has been discussed by combining the activity data and characterization results.

  12. Effects of ultraviolet irradiation on bonding strength between Co-Cr alloy and citric acid-crosslinked gelatin matrix.

    PubMed

    Inoue, Motoki; Sasaki, Makoto; Katada, Yasuyuki; Taguchi, Tetsushi

    2014-02-01

    Novel techniques for creating a strong bond between polymeric matrices and biometals are required. We immobilized polymeric matrices on the surface of biometal for drug-eluting stents through covalent bond. We performed to improve the bonding strength between a cobalt-chromium alloy and a citric acid-crosslinked gelatin matrix by ultraviolet irradiation on the surface of cobalt-chromium alloy. The ultraviolet irradiation effectively generated hydroxyl groups on the surface of the alloy. The bonding strength between the gelatin matrix and the alloy before ultraviolet irradiation was 0.38 ± 0.02 MPa, whereas it increased to 0.48 ± 0.02 MPa after ultraviolet irradiation. Surface analysis showed that the citric acid derivatives occurred on the surface of the cobalt-chromium alloy through ester bond. Therefore, ester bond formation between the citric acid derivatives active esters and the hydroxyl groups on the cobalt-chromium alloy contributed to the enhanced bonding strength. Ultraviolet irradiation and subsequent immobilization of a gelatin matrix using citric acid derivatives is thus an effective way to functionalize biometal surfaces.

  13. Intake of Ethanol, Sodium Chloride, Sucrose, Citric Acid, and Quinine Hydrochloride Solutions by Mice: A Genetic Analysis

    PubMed Central

    Bachmanov, A. A.; Reed, D. R.; Tordoff, M. G.; Price, R. A.; Beauchamp, G. K.

    2013-01-01

    Mice of the 129/J (129) and C57BL/6ByJ (B6) strains and their reciprocal F1 and F2 hybrids were offered solutions of ethanol, sucrose, citric acid, quinine hydrochloride, and NaCI in two-bottle choice tests. Consistent with earlier work, the B6 mice drank more ethanol, sucrose, citric acid, and quinine hydrochloride solution and less NaCI solution than did 129 mice. Analyses of each generation’s means and distributions showed that intakes of ethanol, quinine, sucrose, and NaCI were influenced by a few genes. The mode of inheritance was additive in the case of ethanol and quinine, for sucrose the genotype of the 129 strain was recessive, and for NaCI it was dominant. Citric acid intake appeared to be influenced by many genes with small effects, with the 129 genotype dominant. Correlations of sucrose consumption with ethanol and citric acid consumption were found among mice of the F2 generation, and the genetically determined component of these correlations was stronger than the component related to environmental factors. The genetically determined correlation between sucrose and ethanol intakes is consistent with the hypothesis that the higher ethanol intake by B6 mice depends, in part, on higher hedonic attractiveness of its sweet taste component. PMID:8990535

  14. 77 FR 74171 - Citric Acid and Certain Citrate Salts From the People's Republic of China: Final Results of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-13

    ... citric acid sodium salt, and the monohydrate and monopotassium forms of potassium citrate.\\5\\ Sodium... (``HTSUS''), respectively. Potassium citrate and crude calcium citrate are classifiable under 2918.15.5000... potassium citrate are classifiable under 3824.90.9290 of the HTSUS. Although the HTSUS subheadings are...

  15. 78 FR 34642 - Citric Acid and Certain Citrate Salts From the People's Republic of China: Preliminary Results of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-10

    ... monopotassium forms of potassium citrate.\\1\\ Sodium citrate also includes both trisodium citrate and monosodium... Tariff Schedule of the United States (``HTSUS''), respectively. Potassium citrate and crude calcium... include citric acid, sodium citrate, and potassium citrate are classifiable under 3824.90.9290 of the...

  16. Improving Properties of Arrowroot Starch (Maranta arundinacea)/PVA Blend Films by Using Citric Acid as Cross-linking Agent

    NASA Astrophysics Data System (ADS)

    Sholichah, Enny; Purwono, Bambang; Nugroho, Pramono

    2017-12-01

    This research studied the effect of PVA as organic polymer and citric acid as crosslinker agent in the arrowroot starch/PVA blend films. The properties of films were investigated by water uptake, water vapor permeability, mechanical properties, thermal stability, spectra of FTIR and XRD patterns. PVA used in this research influenced the film properties at the highest concentration. The cross-linkingsinter or intra molecules of arrowroot and PVA were developed as ester bonds which are formed from the reaction of hydroxyl groups consisting of starch and PVA with citric acid. The ester bond was confirmed by FTIR spectra. The increase of the amount of citric acid affected significantly on physical, chemical and mechanical properties, water uptake, WVP and crystallinity. Water barrier level was reduced by decreasing of water uptake and WVP succeeded significantly with increased crosslinking. Cross-linking impact the thermal stability of the films. The elasticity of the films also increases the production of citric acid as a plasticizer in the making of the films as a food packaging material.

  17. The effect of pH on hydrolysis, cross-linking and barrier properties of starch barriers containing citric acid.

    PubMed

    Olsson, Erik; Menzel, Carolin; Johansson, Caisa; Andersson, Roger; Koch, Kristine; Järnström, Lars

    2013-11-06

    Citric acid cross-linking of starch for e.g. food packaging applications has been intensely studied during the last decade as a method of producing water-insensitive renewable barrier coatings. We managed to improve a starch formulation containing citric acid as cross-linking agent for industrial paper coating applications by adjusting the pH of the starch solution. The described starch formulations exhibited both cross-linking of starch by citric acid as well as satisfactory barrier properties, e.g. fairly low OTR values at 50% RH that are comparable with EVOH. Furthermore, it has been shown that barrier properties of coated papers with different solution pH were correlated to molecular changes in starch showing both hydrolysis and cross-linking of starch molecules in the presence of citric acid. Hydrolysis was shown to be almost completely hindered at solution pH≥4 at curing temperatures≤105 °C and at pH≥5 at curing temperatures≤150 °C, whereas cross-linking still occurred to some extent at pH≤6.5 and drying temperatures as low as 70 °C. Coated papers showed a minimum in water vapor transmission rate at pH 4 of the starch coating solution, corresponding to the point where hydrolysis was effectively hindered but where a significant degree of cross-linking still occurred. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Chelating effect of citric acid is negligible for development of enamel erosions.

    PubMed

    Azadi-Schossig, Parastu; Becker, Klaus; Attin, Thomas

    2016-09-01

    Citric acid (CA) is a component in beverages responsible for dental erosion. The aim of this study was to examine the influence of CA with different pH, titratable acid and buffer capacity (ß), and the impact of the chelating effect of CA on development of enamel erosions. In a superfusion model, hydroxy apatite (HAp) dissolution of bovine enamel was measured in four experiments (EXP 1-4) with 27 experimental groups (n = 8 per group). The samples were superfused with different CA variations and respective controls. EXP-1: Dilution series of HCl (pH 2.15-3.02). EXP-2: Dilution series of natural CA (56-1.75 mmol l(-1); pH 2.15-3.02). EXP-3: CA solutions (56 and 14 mmol l(-1), ß: 39.7 and 10.2 mmol l(-1) pH(-1), respectively) with different titratable acidity at equal pH values. EXP-4: CA concentrations (56-1.75 mmol l(-1)) neutralized to pH 7. CA led to higher HAp-dissolution than HCl. With higher pH, the difference in HAp-dissolution rate between the two acids became increasingly smaller. At equal pH, HAp-dissolution was higher for the CA with the higher amount of titratable acid. However, no clear correlation between erosion and titratable acid or ß could be found. Only minimal amounts of HAp were dissolved by neutralized CA compared to CA with natural pH. Under the chosen conditions chelating effects of CA do not have a relevant influence of HAp-dissolution of enamel. Moreover, amount of HAp-dissolution by CA is not attributed to a single factor alone. The interplay between the different parameters of CA seems to be responsible for its erosive potential. The erosive potential of solutions containing citric acid with unknown concentrations could not be predicted using a single parameter alone, and should at best determined in experimental set-ups.

  19. Extended reuse of polysulfone hemodialysis membranes using citric acid and heat.

    PubMed

    Tonelli, Marcello; Dymond, Clayton; Gourishankar, Sita; Jindal, Kailash K

    2004-01-01

    The concomitant use of citric acid and prolonged exposure to heat (CAH) is an increasingly common alternative to purely chemical means of reusing dialyzers. However, there are no data on the effects of reprocessing dialyzers with CAH beyond 15 uses. Increasing the number of reuses with CAH cannot be systematically undertaken unless its safety is documented. We hypothesized that discarding polysulfone dialyzers after the 25th rather than the 15th use would result in increased clearance of beta2-microglobulin (beta2MG) without clinically significant changes in small solute clearance or albumin loss. We studied 15 Fresenius F80B polysulfone dialyzers in five chronic hemodialysis patients. Dialyzers were reprocessed using 1.5% citric acid solution heated to 95 degrees C. Representative fractional collection and 10 minute timed collections of dialysate were performed at baseline and during uses 5, 10, 15, 20, and 25 for each dialyzer. Dialysate-side urea, creatinine, and beta2MG clearances were calculated, and total albumin was measured in dialysate. We used a mixed model to adjust for repeated measures (both within a given dialyzer and for the multiple dialyzers per patient). Of the 15 dialyzers studied, 3 (20%) failed before the 25th use. There was no significant change in urea or creatinine clearance with additional reuse (overall p values 0.20 and 0.60, respectively). A sustained increase in beta2MG clearance was observed after the fifth treatment compared with the first use (p < 0.001). Fractional collection showed that dialysate albumin loss increased significantly with additional reuses (p < 0.001) but did not increase significantly above baseline until treatment 25. Reprocessing of polysulfone dialyzers with CAH 25 times significantly increased albumin loss and beta2MG clearance but did not appear to affect urea or creatinine clearance. Increasing the maximum number of uses to 20 may permit cost savings compared with current practice without additional risk.

  20. Attenuated acute salivary α-amylase responses to gustatory stimulation with citric acid in thin children.

    PubMed

    Chen, Long Hui; Yang, Ze Min; Chen, Wei Wen; Lin, Jing; Zhang, Min; Yang, Xiao Rong; Zhao, Ling Bo

    2015-04-14

    Salivary α-amylase (sAA) is responsible for the 'pre-digestion' of starch in the oral cavity and accounts for up to 50 % of salivary protein in human saliva. An accumulating body of literature suggests that sAA is of nutritional importance; however, it is still not clear how sAA is related to individual's nutritional status. Although copy number variations (CNV) of the salivary amylase gene (AMY1) are associated with variation in sAA levels, a significant amount of sAA variation is not explained by AMY1 CNV. To measure sAA responses to gustatory stimulation with citric acid, we used sAA ratio (the ratio of stimulated sAA levels to those of resting sAA) and investigated acute sAA responses to citric acid in children with normal (Normal-BMI, n 22) and low (Low-BMI, n 21) BMI. The AMY1 gene copy number was determined by quantitative PCR. We, for the first time, demonstrated attenuated acute sAA responses (decreased sAA ratio) to gustatory stimulation in Low-BMI (thinness grade 3) children compared with the Normal-BMI children, which suggest that sAA responses to gustatory stimulation may be of nutritional importance. However, child's nutritional status was not directly related to their resting or stimulated sAA levels, and it was not associated with AMY1 gene copy number. Finally, AMY1 CNV might influence, but did not eventually determine, sAA levels in children.

  1. Citric Acid Metabolism in Resistant Hypertension: Underlying Mechanisms and Metabolic Prediction of Treatment Response.

    PubMed

    Martin-Lorenzo, Marta; Martinez, Paula J; Baldan-Martin, Montserrat; Ruiz-Hurtado, Gema; Prado, Jose Carlos; Segura, Julian; de la Cuesta, Fernando; Barderas, Maria G; Vivanco, Fernando; Ruilope, Luis Miguel; Alvarez-Llamas, Gloria

    2017-11-01

    Resistant hypertension (RH) affects 9% to 12% of hypertensive adults. Prolonged exposure to suboptimal blood pressure control results in end-organ damage and cardiovascular risk. Spironolactone is the most effective drug for treatment, but not all patients respond and side effects are not negligible. Little is known on the mechanisms responsible for RH. We aimed to identify metabolic alterations in urine. In addition, a potential capacity of metabolites to predict response to spironolactone was investigated. Urine was collected from 29 patients with RH and from a group of 13 subjects with pseudo-RH. For patients, samples were collected before and after spironolactone administration and were classified in responders (n=19) and nonresponders (n=10). Nuclear magnetic resonance was applied to identify altered metabolites and pathways. Metabolites were confirmed by liquid chromatography-mass spectrometry. Citric acid cycle was the pathway most significantly altered ( P <0.0001). Metabolic concentrations were quantified and ranged from ng/mL malate to μg/mL citrate. Citrate and oxaloacetate increased in RH versus pseudoresistant. Together with α-ketoglutarate and malate, they were able to discriminate between responders and nonresponders, being the 4 metabolites increased in nonresponders. Combined as a prediction panel, they showed receiver operating characteristiccurve with area under the curve of 0.96. We show that citric acid cycle and deregulation of reactive oxygen species homeostasis control continue its activation after hypertension was developed. A metabolic panel showing alteration before spironolactone treatment and predicting future response of patients is shown. These molecular indicators will contribute optimizing the rate of control of RH patients with spironolactone. © 2017 American Heart Association, Inc.

  2. Antifouling polyethersulfone hemodialysis membranes incorporated with poly (citric acid) polymerized multi-walled carbon nanotubes.

    PubMed

    Abidin, Muhammad Nidzhom Zainol; Goh, Pei Sean; Ismail, Ahmad Fauzi; Othman, Mohd Hafiz Dzarfan; Hasbullah, Hasrinah; Said, Noresah; Kadir, Siti Hamimah Sheikh Abdul; Kamal, Fatmawati; Abdullah, Mohd Sohaimi; Ng, Be Cheer

    2016-11-01

    Poly (citric acid)-grafted-MWCNT (PCA-g-MWCNT) was incorporated as nanofiller in polyethersulfone (PES) to produce hemodialysis mixed matrix membrane (MMM). Citric acid monohydrate was polymerized onto the surface of MWCNTs by polycondensation. Neat PES membrane and PES/MWCNTs MMMs were fabricated by dry-wet spinning technique. The membranes were characterized in terms of morphology, pure water flux (PWF) and bovine serum albumin (BSA) protein rejection. The grafting yield of PCA onto MWCNTs was calculated as 149.2%. The decrease of contact angle from 77.56° to 56.06° for PES/PCA-g-MWCNTs membrane indicated the increase in surface hydrophilicity, which rendered positive impacts on the PWF and BSA rejection of the membrane. The PWF increased from 15.8Lm(-2)h(-1) to 95.36Lm(-2)h(-1) upon the incorporation of PCA-g-MWCNTs due to the attachment of abundant hydrophilic groups that present on the MWCNTs, which have improved the affinity of membrane towards the water molecules. For protein rejection, the PES/PCA-g-MWCNTs MMM rejected 95.2% of BSA whereas neat PES membrane demonstrated protein rejection of 90.2%. Compared to commercial PES hemodialysis membrane, the PES/PCA-g-MWCNTs MMMs showed less flux decline behavior and better PWF recovery ratio, suggesting that the membrane antifouling performance was improved. The incorporation of PCA-g-MWCNTs enhanced the separation features and antifouling capabilities of the PES membrane for hemodialysis application. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Enhanced solid-state citric acid bio-production using apple pomace waste through surface response methodology.

    PubMed

    Dhillon, G S; Brar, S K; Verma, M; Tyagi, R D

    2011-04-01

      To evaluate the potential of apple pomace (AP) supplemented with rice husk for hyper citric acid production through solid-state fermentation by Aspergillus niger NRRL-567. Optimization of two key parameters, such as moisture content and inducer (ethanol and methanol) concentration was carried out by response surface methodology.   In this study, the effect of two crucial process parameters for solid-state citric acid fermentation by A. niger using AP waste supplemented with rice husk were thoroughly investigated in Erlenmeyer flasks through response surface methodology. Moisture and methanol had significant positive effect on citric acid production by A. niger grown on AP (P < 0·05). Higher values of citric acid on AP by A. niger (342·41gkg(-1) and 248·42gkg(-1) dry substrate) were obtained with 75% (v/w) moisture along with two inducers [3% (v/w) methanol and 3% (v/w) ethanol] with fermentation efficiency of 93·90% and 66·42%, respectively depending upon the total carbon utilized after 144h of incubation period. With the same optimized parameters, conventional tray fermentation was conducted. The citric acid concentration of 187·96gkg(-1) dry substrate with 3% (v/w) ethanol and 303·34gkg(-1) dry substrate with 3% (v/w) methanol were achieved representing fermentation efficiency of 50·80% and 82·89% in tray fermentation depending upon carbon utilization after 120h of incubation period.   Apple pomace proved to be the promising substrate for the hyper production of citric acid through solid-state tray fermentation, which is an economical technique and does not require any sophisticated instrumentation.   The study established that the utilization of agro-industrial wastes have positive repercussions on the economy and will help to meet the increasing demands of citric acid and moreover will help to alleviate the environmental problems resulting from the disposal of agro-industrial wastes. © 2011 The Authors. Journal of Applied Microbiology

  4. The opposite roles of agdA and glaA on citric acid production in Aspergillus niger.

    PubMed

    Wang, Lu; Cao, Zhanglei; Hou, Li; Yin, Liuhua; Wang, Dawei; Gao, Qiang; Wu, Zhenqiang; Wang, Depei

    2016-07-01

    Citric acid is produced by an industrial-scale process of fermentation using Aspergillus niger as a microbial cell factory. However, citric acid production was hindered by the non-fermentable isomaltose and insufficient saccharification ability in A. niger when liquefied corn starch was used as a raw material. In this study, A. niger TNA 101ΔagdA was constructed by deletion of the α-glucosidase-encoding agdA gene in A. niger CGMCC 10142 genome using Agrobacterium tumefaciens-mediated transformation. The transformants A. niger OG 1, OG 17, and OG 31 then underwent overexpression of glucoamylase in A. niger TNA 101ΔagdA. The results showed that the α-glucosidase activity of TNA 101ΔagdA was decreased by 62.5 % compared with CGMCC 10142, and isomaltose was almost undetectable in the fermentation broth. The glucoamylase activity of the transformants OG 1 and OG 17 increased by 34.5 and 16.89 % compared with that of TNA 101ΔagdA, respectively. In addition, for the recombinants TNA 101ΔagdA, OG 1 and OG 17, there were no apparent defects in the growth development. Consequently, in comparison with CGMCC 10142, TNA 101ΔagdA and OG 1 decreased the residual reducing sugar by 52.95 and 88.24 %, respectively, and correspondingly increased citric acid production at the end of fermentation by 8.68 and 16.87 %. Citric acid production was further improved by decreasing the non-fermentable residual sugar and increasing utilization rate of corn starch material in A. niger. Besides, the successive saccharification and citric acid fermentation processes were successfully integrated into one step.

  5. [Effects of low molecular weight organic acids on redox reactions of mercury].

    PubMed

    Zhao, Shi-Bo; Sun, Rong-Guo; Wang, Ding-Yong; Wang, Xiao-Wen; Zhang, Cheng

    2014-06-01

    To study the effects of the main component of vegetation root exudates-low molecular weight organic acids on the redox reactions of mercury, laboratory experiments were conducted to investigate the roles of tartaric, citric, and succinic acid in the redox reactions of mercury, and to analyze their interaction mechanism. The results indicated that tartaric acid significantly stimulated the mercury reduction reaction, while citric acid had inhibitory effect. Succinic acid improved the reduction rate at low concentration, and inhibited the reaction at high concentration. The mercury reduction rate by tartaric acid treatment was second-order with respect to Hg2+ concentration, ranging from 0.0014 L x (ng x min)(-1) to 0.005 6 L x (ng x min)(-1). All three organic acids showed a capacity for oxidating Hg(0) in the early stage, but the oxidized Hg(0) was subsequently reduced. The oxidation capacity of the three organic acids was in the order of citric acid > tartaric acid > succinic acid.

  6. Influence of citric acid on the surface texture of glass ionomer restorative materials

    PubMed Central

    Reddy, Dappili Swami Ranga; Kumar, Ramachandran Anil; Venkatesan, Sokkalingam Mothilal; Narayan, Gopal Shankar; Duraivel, Dasarathan; Indra, Rajamani

    2014-01-01

    Aim: This study determined the effectiveness of G-coat plus surface protective agent over petroleum jelly on the surface texture of conventional Glass ionomer restorative materials. Materials and Methods: Three chemically cured conventional glass ionomer restorative materials type II, type IX and ketac molar were evaluated in this study. Sixty specimens were made for each restorative material. They were divided into two groups of thirty specimens each. Of the sixty specimens, thirty were coated with G-coat plus (a nano-filler coating) and the rest with petroleum jelly. Thirty samples of both protective coating agents were randomly divided into six groups of five specimens and conditioned in citric acid solutions of differing pH (pH 2, 3, 4, 5, 6 & 7). Each specimen was kept in citric acid for three hours a day, and the rest of time stored in salivary substitute. This procedure was repeated for 8 days. After conditioning, the surface roughness (Ra, μm) of each specimen was measured using a surface profilometer (Taylor & Habson, UK). Data was analyzed using one-way analysis of variance (ANOVA) and Tukey's HSD test at a significance level of 0.05. Results: The surface textures of all the tested glass ionomer restorative materials protected with G-coat plus were not significantly affected by acids at low pH. The surface textures of all the tested glass ionomer restorative materials protected with petroleum jelly coating were significantly affected by acids at low pH. Conclusion: The effects of pH on the surface texture of glass ionomer restoratives are material dependent. Among all the materials tested the surface texture of Type II GIC (Group I) revealed marked deterioration when conditioned in solutions of low pH and was statistically significant. Hence, a protective coating either with G-coat plus or with light polymerized low viscosity unfilled resin adhesives is mandatory for all the glass ionomer restorations to increase the wear resistance of the restorative

  7. [Evaluation of compounding EDTA and citric acid on remediation of heavy metals contaminated soil].

    PubMed

    Yin, Xue; Chen, Jia-Jun; Cai, Wen-Min

    2014-08-01

    As commonly used eluents, Na2EDTA (EDTA) and citric acid (CA) have been widely applied in remediation of soil contaminated by heavy metals. In order to evaluate the removal of arsenic, cadmium, copper, and lead in the contaminated soil collected in a chemical plant by compounding EDTA and CA, a series of stirring experiments were conducted. Furthermore, the changes in speciation distribution of heavy metals before and after washing were studied. The results showed that, adopting the optimal molar ratio of EDTA/CA (1:1), when the pH of the solution was 3, the stirring time was 30 min, the stirring rate was 150 r x min(-1) and the L/S was 5:1, the removal rates of arsenic, cadmium, copper and lead could reach 11.72%, 43.39%, 24.36% and 27.17%, respectively. And it was found that after washing, for arsenic and copper, the content of acid dissolved fraction rose which increased the percentage of available contents. Fe-Mn oxide fraction mainly contributed to the removal of copper. As for cadmium, the percentages of acid dissolved fraction, Fe-Mn oxide fraction and organic fraction also decreased. In practical projects, speciation changes would pose certain environmental risk after soil washing, which should be taken into consideration.

  8. Optimization of pectin extraction from banana peels with citric acid by using response surface methodology.

    PubMed

    Oliveira, Túlio Ítalo S; Rosa, Morsyleide F; Cavalcante, Fabio Lima; Pereira, Paulo Henrique F; Moates, Graham K; Wellner, Nikolaus; Mazzetto, Selma E; Waldron, Keith W; Azeredo, Henriette M C

    2016-05-01

    A central composite design was used to determine effects of pH (2.0-4.5), extraction temperature (70-90 °C) and time (120-240 min) on the yield, degree of methoxylation (DM) and galacturonic acid content (GA) of pectins extracted from banana peels with citric acid. Changes in composition during the main steps of pectin extraction were followed by Fourier transform infrared (FTIR) spectroscopy. FTIR was also used to determine DM and GA of pectins. Harsh temperature and pH conditions enhanced the extraction yield, but decreased DM. GA presented a maximum value at 83 °C, 190 min, and pH 2.7. The yield of galacturonic acid (YGA), which took into account both the extraction yield and the pectin purity, was improved by higher temperature and lower pH values. The optimum extraction conditions, defined as those resulting in a maximum YGA while keeping DM at a minimum of 51%, were: 87 °C, 160 min, pH 2.0. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Quantitative GC-MS assay of citric acid from humans and db/db mice blood serum to assist the diagnosis of diabetic nephropathy.

    PubMed

    Gao, Haoxue; Yu, Xiaoyi; Sun, Runbin; Yang, Na; He, Jun; Tao, Mingxue; Gu, Huilin; Yan, Caixia; Aa, Jiye; Wang, Guangji

    2018-03-01

    The early diagnosis of diabetic nephropathy (DN) is rather challenging. Our previous study suggested that citric acid is a potential marker for the early diagnosis of diabetic nephropathy in db/db mice. For the first time, in this study, a surrogate analyte of 13 C 6 -citric acid was employed to generate calibration curves for the quantitative measurement of the endogenous citric acid in the sera of db/db mice and diabetic nephropathy patients by GC/MS after the analytes were extracted, methoximated and trimethylsilylated. The constant response factor of 13 C 6 -citric acid versus citric acid over the linear range indicated the identical ionization efficiency of these two compounds. The full validation assessments suggested that the method is sensitive, specific, reliable, reproducible and has acceptable parameters. Statistical analysis revealed cut-off citric acid concentrations of 29.24 μg/mL with a 95% confidence interval between 32.75 and 39.16 μg/mL in the diabetic nephropathy patients and 16.74 and 22.57 μg/mL in the normal controls. The areas under the receiver operating characteristic curves indicated accuracies of over 90% for the diagnoses of early diabetic nephropathy in both humans and db/db mice, which suggests that the serum citric acid level is potentially a biomarker that could assist in the diagnosis of diabetic nephropathy. Copyright © 2018 Elsevier B.V. All rights reserved.

  10. Effects of citric acid and the siderophore desferrioxamine B (DFO-B) on the mobility of germanium and rare earth elements in soil and uptake in Phalaris arundinacea.

    PubMed

    Wiche, Oliver; Tischler, Dirk; Fauser, Carla; Lodemann, Jana; Heilmeier, Hermann

    2017-08-03

    Effects of citric acid and desferrioxamine B (DFO-B) on the availability of Ge and selected rare earth elements (REEs) (La, Nd, Gd, Er) to Phalaris arundinacea were investigated. A soil dissolution experiment was conducted to elucidate the effect of citric acid and DFO-B at different concentrations (1 and 10 mmol L -1 citric acid) on the release of Ge and REEs from soil. In a greenhouse, plants of P. arundinacea were cultivated on soil and on sand cultures to investigate the effects of citric acid and DFO-B on the uptake of Ge and REEs by the plants. Addition of 10 mmol L -1 citric acid significantly enhanced desorption of Ge and REEs from soil and uptake into soil-grown plants. Applying DFO-B enhanced the dissolution and the uptake of REEs, while no effect on Ge was observed. In sand cultures, the presence of citric acid and DFO-B significantly decreased the uptake of Ge and REEs, indicating a discrimination of the formed complexes during uptake. This study clearly indicates that citric acid and the microbial siderophore DFO-B may enhance phytoextraction of Ge and REEs due to the formation of soluble complexes that increase the migration of elements in the rhizosphere.

  11. Tartaric acid assisted hydrothermal synthesis of different flower-like ZnO hierarchical architectures with tunable optical and oxygen vacancy-induced photocatalytic properties

    NASA Astrophysics Data System (ADS)

    Liu, Tingzhi; Li, Yangyang; Zhang, Hao; Wang, Min; Fei, Xiaoyan; Duo, Shuwang; Chen, Ying; Pan, Jian; Wang, Wei

    2015-12-01

    Different flower-like ZnO hierarchical architectures were prepared by tartaric acid assisted hydrothermal synthesis, especially four flower-like ZnO nanostructures were obtained simultaneously under the same reaction condition. The cauliflower-like ZnO is assembled by spherical shaped nanoparticles, and the chrysanthemum-like and other flower-like ZnO nanostructures are assembled by hexagonal rods/prisms with from planar to semi-pyramid, and to pyramid tips. TA acts as a capping agent and structure-directing agent during the synthesis. All ZnO possess the hexagonal wurtzite structure. The PL spectra can be tuned by changing TA concentration. XRD, PL and Raman spectra confirmed that oxygen vacancies mainly come from the ZnO surface. The flower-like samples of 1:4.5 and 1:3 with the largest aspect ratios have highest photocatalytic performance. They decompose 85% MB within 60 min. Combining PL Gaussian fitting with K, the higher content of oxygen vacancy is, the higher photocatalytic activity is. The enhanced photocatalytic performance is mainly induced by oxygen vacancy of ZnO. The possible formation mechanism, growth and change process of flower-like ZnO were proposed.

  12. Synthesis, spectroscopic characterization and structural studies of a new proton transfer (H-bonded) complex of o-phenylenediamine with L-tartaric acid

    NASA Astrophysics Data System (ADS)

    Khan, Ishaat M.; Ahmad, Afaq

    2013-10-01

    A proton transfer or H-bonded (CT) complex of o-phenylenediamine (OPD) as donor with L-tartaric acid (TART) as acceptor was synthesized and characterized by spectral techniques such as FTIR, 1H NMR, elemental analysis, TGA-TDA, X-ray crystallography and spectrophotometric studies. The structural investigations exhibit that the cation [OPD+] and anion [TART-] are linked together through strong N+-H⋯O- type hydrogen bonds due to transfer of proton from acceptor to donor. Formed H-bonded complex exhibits well resolved proton transfer bands in the regions where neither donor nor acceptor has any absorption. The stoichiometry of the H-bonded complex (HBC) was found to be 1:1, determined by straight line methods. Spectrophotometric studies have been performed at room temperature and Benesi-Hildebrand equation was used to determine formation constant (KCT), molar extinction coefficient (ɛCT) and also transition energy (ECT) of the H-bonded complex. Spectrophotomeric and crystallographic studies have ascertained the formation of 1:1 H-bonded complex. Thermal analysis (TGA-DTA) was also used to confirm the thermal fragmentation and the stability of the synthesized H-bonded complex.

  13. Enhanced phytoextraction: II. Effect of EDTA and citric acid on heavy metal uptake by Helianthus annuus from a calcareous soil.

    PubMed

    Lesage, E; Meers, E; Vervaeke, P; Lamsal, S; Hopgood, M; Tack, F M G; Verloo, M G

    2005-01-01

    High biomass producing plant species, such as Helianthus annuus, have potential for removing large amounts of trace metals by harvesting the aboveground biomass if sufficient metal concentrations in their biomass can be achieved However, the low bioavailability of heavy metals in soils and the limited translocation of heavy metals to the shoots by most high biomass producing plant species limit the efficiency of the phytoextraction process. Amendment of a contaminated soil with ethylene diamine tetraacetic acid (EDTA) or citric acid increases soluble heavy metal concentrations, potentially rendering them more available for plant uptake. This article discusses the effects of EDTA and citric acid on the uptake of heavy metals and translocation to aboveground harvestable plant parts in Helianthus annuus. EDTA was included in the research for comparison purposes in our quest for less persistent alternatives, suitable for enhanced phytoextraction. Plants were grown in a calcareous soil moderately contaminated with Cu, Pb, Zn, and Cd and treated with increasing concentrations of EDTA (0.1, 1, 3, 5, 7, and 10 mmol kg(-1) soil) or citric acid (0.01, 0.05, 0.25, 0.442, and 0.5 mol kg(-1) soil). Heavy metal concentrations in harvested shoots increased with EDTA concentration but the actual amount of phytoextracted heavy metals decreased at high EDTA concentrations, due to severe growth depression. Helianthus annuus suffered heavy metal stress due to the significantly increased bioavailable metal fraction in the soil. The rapid mineralization of citric acid and the high buffering capacity of the soil made citric acid inefficient in increasing the phytoextracted amounts of heavy metals. Treatments that did not exceed the buffering capacity of the soil (< 0.442 mol kg(-1) soil) did not result in any significant increase in shoot heavy metal concentrations. Treatments with high concentrations resulted in a dissolution of the carbonates and compaction of the soil. These

  14. Mitochondria dysfunctions under Fe and S deficiency: is citric acid involved in the regulation of adaptive responses?

    PubMed

    Vigani, Gianpiero; Pii, Youry; Celletti, Silvia; Maver, Mauro; Mimmo, Tanja; Cesco, Stefano; Astolfi, Stefania

    2018-05-01

    Within the last years, extensive information has been accumulated on the reciprocal influence between S and Fe nutrition at both physiological and molecular level in several plant species, but the mechanisms regulating S and Fe sensing and signaling are not fully understood. Fe and S interact for the building of Fe-S clusters, and mitochondria is one of the cellular compartments where Fe-S cluster assembly takes place. Therefore, it would be expected that mitochondria might play a central role in the regulation of Fe and S interaction. The Fe deficiency-induced alteration in the synthesis of mitochondria-derived carboxylic acids, such as citric acid, and the evidence that such molecules have already been identified as important players of metabolite signaling in several organisms, further support this hypothesis. Tomato plants were grown under single or combined Fe and S deficiency with the aim of verifying whether mitochondria activities played a role in Fe/S interaction. Both Fe and S deficiencies determined similar alteration of respiratory chain activity: a general decrease of Fe-S containing complexes as well as an increase of alternative NAD(P)H activities was observed in both Fe and S deficient-plants. However, the content of Krebs cycle-related organic acids in roots was substantially different in response to treatments, being the accumulation of citric acid always increased, while the others (i.e. succinic, malic, fumaric acids) always decreased. Interestingly, citric acid levels significantly correlated with the expression of some Fe and S deficiency induced genes. Our results contribute to existing knowledge on the complexity of the S/Fe interaction, suggesting a model in which endogenous alteration of citric acid content in plant tissues might act as signal molecule for the regulation of some nuclear-encoded and nutrient-responsive genes and also provide a basis for further study of the mechanism underlying S and Fe sensing and signalling. Copyright

  15. Overexpression of a C4-dicarboxylate transporter is the key for rerouting citric acid to C4-dicarboxylic acid production in Aspergillus carbonarius.

    PubMed

    Yang, Lei; Christakou, Eleni; Vang, Jesper; Lübeck, Mette; Lübeck, Peter Stephensen

    2017-03-14

    C 4 -dicarboxylic acids, including malic acid, fumaric acid and succinic acid, are valuable organic acids that can be produced and secreted by a number of microorganisms. Previous studies on organic acid production by Aspergillus carbonarius, which is capable of producing high amounts of citric acid from varieties carbon sources, have revealed its potential as a fungal cell factory. Earlier attempts to reroute citric acid production into C 4 -dicarboxylic acids have been with limited success. In this study, a glucose oxidase deficient strain of A. carbonarius was used as the parental strain to overexpress a native C 4 -dicarboxylate transporter and the gene frd encoding fumarate reductase from Trypanosoma brucei individually and in combination. Impacts of the introduced genetic modifications on organic acid production were investigated in a defined medium and in a hydrolysate of wheat straw containing high concentrations of glucose and xylose. In the defined medium, overexpression of the C 4 -dicarboxylate transporter alone and in combination with the frd gene significantly increased the production of C 4 -dicarboxylic acids and reduced the accumulation of citric acid, whereas expression of the frd gene alone did not result in any significant change of organic acid production profile. In the wheat straw hydrolysate after 9 days of cultivation, similar results were obtained as in the defined medium. High amounts of malic acid and succinic acid were produced by the same strains. This study demonstrates that the key to change the citric acid production into production of C 4 -dicarboxylic acids in A. carbonarius is the C 4 -dicarboxylate transporter. Furthermore it shows that the C 4 -dicarboxylic acid production by A. carbonarius can be further increased via metabolic engineering and also shows the potential of A. carbonarius to utilize lignocellulosic biomass as substrates for C 4 -dicarboxylic acid production.

  16. Citric Acid Enhanced Copper Removal by a Novel Multi-amines Decorated Resin

    PubMed Central

    Ling, Chen; Liu, Fuqiang; Pei, Zhiguo; Zhang, Xiaopeng; Wei, Mengmeng; Zhang, Yanhong; Zheng, Lirong; Zhang, Jing; Li, Aimin; Xing, Baoshan

    2015-01-01

    Cu removal by a novel multi-amines decorated resin (PAMD) from wastewater in the absence or presence of citric acid (CA) was examined. Adsorption capacity of Cu onto PAMD markedly increased by 186% to 5.07 mmol/g in the presence of CA, up to 7 times of that onto four commercial resins under the same conditions. Preloaded and kinetic studies demonstrated adsorption of [Cu-CA] complex instead of CA site-bridging and variations of adsorbate species were qualitatively illustrated. The interaction configuration was further studied with ESI-MS, FTIR, XPS and XANES characterizations. The large enhancement of Cu adsorption in Cu-CA bi-solutes systems was attributed to mechanism change from single-site to dual-sites interaction in which cationic or neutral Cu species (Cu2+ and CuHL0) coordinated with neutral amine sites and anionic complex species (CuL− and Cu2L22−) directly interacted with protonated amine sites via electrostatic attraction, and the ratio of the two interactions was approximately 0.5 for the equimolar bi-solutes system. Moreover, commonly coexisting ions in wastewaters had no obvious effect on the superior performance of PAMD. Also, Cu and CA could be recovered completely with HCl. Therefore, PAMD has a great potential to efficiently remove heavy metal ions from wastewaters in the presence of organic acids. PMID:25962970

  17. Kinetic Study on the Removal of Iron from Gold Mine Tailings by Citric Acid

    NASA Astrophysics Data System (ADS)

    Mashifana, T.; Mavimbela, N.; Sithole, N.

    2018-03-01

    The Gold mining generates large volumes of tailings, with consequent disposal and environmental problems. Iron tends to react with sulphur to form pyrite and pyrrhotite which then react with rain water forming acid rain. The study focuses on the removal of iron (Fe) from Gold Mine tailings; Fe was leached using citric acid as a leaching reagent. Three parameters which have an effect on the removal of Fe from the gold mine tailings, namely; temperature (25 °C and 50 °C), reagent concentration (0.25 M, 0.5 M, 0.75 M and 1 M) and solid loading ratio (20 %, 30 % and 40 %) were investigated. It was found that the recovery of Fe from gold mine tailings increased with increasing temperature and reagent concentration, but decreased with increasing solid loading ratio. The optimum conditions for the recovery of Fe from gold mine tailings was found to be at a temperature of 50 ºC, reagent concentration of 1 M and solid loading of 20 %. Three linear kinetic models were investigated and Prout-Tompkins kinetic model was the best fit yielding linear graphs with the highest R2 values.

  18. Effect of Citric Acid Surface Modification on Solubility of Hydroxyapatite Nanoparticles.

    PubMed

    Samavini, Ranuri; Sandaruwan, Chanaka; De Silva, Madhavi; Priyadarshana, Gayan; Kottegoda, Nilwala; Karunaratne, Veranja

    2018-04-04

    Worldwide, there is an amplified interest in nanotechnology-based approaches to develop efficient nitrogen, phosphorus, and potassium fertilizers to address major challenges pertaining to food security. However, there are significant challenges associated with fertilizer manufacture and supply as well as cost in both economic and environmental terms. The main issues relating to nitrogen fertilizer surround the use of fossil fuels in its production and the emission of greenhouse gases resulting from its use in agriculture; phosphorus being a mineral source makes it nonrenewable and casts a shadow on its sustainable use in agriculture. This study focuses on development of an efficient P nutrient system that could overcome the inherent problems arising from current P fertilizers. Attempts are made to synthesize citric acid surface-modified hydroxyapatite nanoparticles using wet chemical precipitation. The resulting nanohybrids were characterized using powder X-ray diffraction to extract the crystallographic data, while functional group analysis was done by Fourier transform infrared spectroscopy. Morphology and particle size were studied using scanning electron microscopy along with elemental analysis using energy-dispersive X-ray diffraction spectroscopy. Its effectiveness as a source of P was investigated using water release studies and bioavailability studies using Zea mays as the model crop. Both tests demonstrated the increased availability of P from nanohybrids in the presence of an organic acid compared with pure hydroxyapatite nanoparticles and rock phosphate.

  19. Metabolic peculiarities of the citric acid overproduction from glucose in yeasts Yarrowia lipolytica.

    PubMed

    Kamzolova, Svetlana V; Morgunov, Igor G

    2017-11-01

    Comparative study of 43 natural yeast strains belonging to 20 species for their capability for overproduction of citric acid (CA) from glucose under nitrogen limitation of cell growth was carried out. As a result, natural strain Yarrowia lipolytica VKM Y-2373 was selected. The effect of growth limitation by biogenic macroelements (nitrogen, phosphorus, or sulfur) on the CA production by the selected strain was studied. It was shown that yeasts Y. lipolytica grown under deficiency of nitrogen, phosphorus, or sulfur were able to excrete CA in industrially sufficient amounts (80-85g/L with the product yield (Y CA ) of 0.70-0.75g/g and the process selectivity of 92.5-95.3%). Based on the obtained data on activities of enzymes involved in the initial stages of glucose oxidation, the cycle of tricarboxylic acids, and the glyoxylate cycle, the conception of the mechanism responsible for the CA overproduction from glucose in Y. lipolytica was formulated. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Effect of whey protein isolate films incorporated with montmorillonite and citric acid on the preservation of fresh-cut apples.

    PubMed

    Azevedo, Viviane Machado; Dias, Marali Vilela; de Siqueira Elias, Heloisa Helena; Fukushima, Katia Lumi; Silva, Eric Keven; de Deus Souza Carneiro, João; de Fátima Ferreira Soares, Nilda; Borges, Soraia Vilela

    2018-05-01

    The objective of this paper was to evaluate the effect of bioactive whey protein isolate/montmorillonite films containing citric acid on the inhibition of enzymatic browning and physicochemical properties in minimally processed apples. Whey protein isolate films incorporated with montmorillonite (3 g/100 g) and citric acid (5 and 10 g/100 g) were applied to the apples slices. All samples were packaged in polypropylene trays (14.6 cm × 11.4 cm × 6.5 cm) and stored at 5 ± 2 °C and 85 ± 3% RH for eight days. Every two days, the apples samples were evaluated for color, acidity, pH, soluble solids, water activity and polyphenol oxidase and peroxidase enzyme activity. The enzymatic browning of the apples slices was reduced for all films during storage. However, the films containing citric acid maintained the color characteristics, reducing the loss of quality associated the maintenance of acidity, soluble solids, water activity, reduction of polyphenol oxidase and peroxidase activity, thus prolonging the shelf life of the apples. Copyright © 2018 Elsevier Ltd. All rights reserved.

  1. In vitro digestion of citric acid esters of mono- and diglycerides (CITREM) and CITREM-containing infant formula/emulsions.

    PubMed

    Amara, Sawsan; Patin, Amaury; Giuffrida, Francesca; Wooster, Tim J; Thakkar, Sagar K; Bénarouche, Anaïs; Poncin, Isabelle; Robert, Sylvie; Point, Vanessa; Molinari, Sacha; Gaussier, Hélène; Diomande, Sadia; Destaillats, Frédéric; Cruz-Hernandez, Cristina; Carrière, Frédéric

    2014-07-25

    CITREM is an emulsifier used in the food industry and contains citric acid esters of mono- and diglycerides (GCFE). It is generally recognized as safe but no publication on its digestibility under gastrointestinal conditions and impact on fat digestion was available. It was shown here that fatty acids are released from CITREM by gastric lipase, pancreatic lipase, pancreatic-lipase-related protein 2 and carboxyl ester hydrolase. A two-step in vitro digestion model mimicking lipolysis in the stomach and upper small intestine of term and preterm infants was then used to evaluate the digestibility of CITREM alone, CITREM-containing infant formula and fat emulsions, and isolated GCFE fractions. Overall, it was shown that fat digestion is not significantly changed by the presence of CITREM, and fatty acids contained in CITREM compounds are released to a large extent by lipases. Nevertheless, undigestible water-soluble compounds containing glycerol and citric acid units were identified, indicating that the ester bond between citric acid and glycerol is not fully hydrolyzed throughout the proposed digestion.

  2. Overexpression of the NADP+-specific isocitrate dehydrogenase gene (icdA) in citric acid-producing Aspergillus niger WU-2223L.

    PubMed

    Kobayashi, Keiichi; Hattori, Takasumi; Hayashi, Rie; Kirimura, Kohtaro

    2014-01-01

    In the tricarboxylic acid (TCA) cycle, NADP(+)-specific isocitrate dehydrogenase (NADP(+)-ICDH) catalyzes oxidative decarboxylation of isocitric acid to form α-ketoglutaric acid with NADP(+) as a cofactor. We constructed an NADP(+)-ICDH gene (icdA)-overexpressing strain (OPI-1) using Aspergillus niger WU-2223L as a host and examined the effects of increase in NADP(+)-ICDH activity on citric acid production. Under citric acid-producing conditions with glucose as the carbon source, the amounts of citric acid produced and glucose consumed by OPI-1 for the 12-d cultivation period decreased by 18.7 and 10.5%, respectively, compared with those by WU-2223L. These results indicate that the amount of citric acid produced by A. niger can be altered with the NADP(+)-ICDH activity. Therefore, NADP(+)-ICDH is an important regulator of citric acid production in the TCA cycle of A. niger. Thus, we propose that the icdA gene is a potentially valuable tool for modulating citric acid production by metabolic engineering.

  3. Quality enhancement in the Japanese sea bass (Lateolabrax japonicas) fillets stored at 4°C by chitosan coating incorporated with citric acid or licorice extract.

    PubMed

    Qiu, Xujian; Chen, Shengjun; Liu, Guangming; Yang, Qiuming

    2014-11-01

    The preserving effects of chitosan, chitosan and citric acid, chitosan and licorice extract on fresh Japanese sea bass fillets stored at 4 °C for 12 days were studied. Results showed that citric acid or licorice extract can enhance the preserving function of chitosan significantly by retarding lipid oxidation and inhibiting microbial growth as reflected in thiobarbituric acid reactive substances and total plate count, respectively. Both total volatile basic nitrogen values and sensory scores indicated chitosan and citric acid or licorice extract can significantly reduce the quality loss and extend the shelf life of Japanese sea bass fish fillets during refrigerated storage. Citric acid or licorice extract with chitosan could thus be applied in the seafood industry to enhance quality of fish fillets as natural preservatives. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Blood metabolomics analysis identifies abnormalities in the citric acid cycle, urea cycle, and amino acid metabolism in bipolar disorder.

    PubMed

    Yoshimi, Noriko; Futamura, Takashi; Kakumoto, Keiji; Salehi, Alireza M; Sellgren, Carl M; Holmén-Larsson, Jessica; Jakobsson, Joel; Pålsson, Erik; Landén, Mikael; Hashimoto, Kenji

    2016-06-01

    Bipolar disorder (BD) is a severe and debilitating psychiatric disorder. However, the precise biological basis remains unknown, hampering the search for novel biomarkers. We performed a metabolomics analysis to discover novel peripheral biomarkers for BD. We quantified serum levels of 116 metabolites in mood-stabilized male BD patients (n = 54) and age-matched male healthy controls (n = 39). After multivariate logistic regression, serum levels of pyruvate, N-acetylglutamic acid, α-ketoglutarate, and arginine were significantly higher in BD patients than in healthy controls. Conversely, serum levels of β-alanine, and serine were significantly lower in BD patients than in healthy controls. Chronic (4-weeks) administration of lithium or valproic acid to adult male rats did not alter serum levels of pyruvate, N-acetylglutamic acid, β-alanine, serine, or arginine, but lithium administration significantly increased serum levels of α-ketoglutarate. The metabolomics analysis demonstrated altered serum levels of pyruvate, N-acetylglutamic acid, β-alanine, serine, and arginine in BD patients. The present findings suggest that abnormalities in the citric acid cycle, urea cycle, and amino acid metabolism play a role in the pathogenesis of BD.

  5. Ultrasound-assisted extraction of pectins from grape pomace using citric acid: a response surface methodology approach.

    PubMed

    Minjares-Fuentes, R; Femenia, A; Garau, M C; Meza-Velázquez, J A; Simal, S; Rosselló, C

    2014-06-15

    An ultrasound-assisted procedure for the extraction of pectins from grape pomace with citric acid as the extracting agent was established. A Box-Behnken design (BBD) was employed to optimize the extraction temperature (X1: 35-75°C), extraction time (X2: 20-60 min) and pH (X3: 1.0-2.0) to obtain a high yield of pectins with high average molecular weight (MW) and degree of esterification (DE) from grape pomace. Analysis of variance showed that the contribution of a quadratic model was significant for the pectin extraction yield and for pectin MW whereas the DE of pectins was more influenced by a linear model. An optimization study using response surface methodology was performed and 3D response surfaces were plotted from the mathematical model. According to the RSM model, the highest pectin yield (∼32.3%) can be achieved when the UAE process is carried out at 75°C for 60 min using a citric acid solution of pH 2.0. These pectic polysaccharides, composed mainly by galacturonic acid units (<97% of total sugars), have an average MW of 163.9 kDa and a DE of 55.2%. Close agreement between experimental and predicted values was found. These results suggest that ultrasound-assisted extraction could be a good option for the extraction of functional pectins with citric acid from grape pomace at industrial level. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Data of thermal degradation and dynamic mechanical properties of starch–glycerol based films with citric acid as crosslinking agent

    PubMed Central

    González Seligra, Paula; Medina Jaramillo, Carolina; Famá, Lucía; Goyanes, Silvia

    2016-01-01

    Interest in biodegradable edible films as packaging or coating has increased because their beneficial effects on foods. In particular, food products are highly dependents on thermal stability, integrity and transition process temperatures of the packaging. The present work describes a complete data of the thermal degradation and dynamic mechanical properties of starch–glycerol based films with citric acid (CA) as crosslinking agent described in the article titled: “Biodegradable and non-retrogradable eco-films based on starch–glycerol with citric acid as crosslinking agent” González Seligra et al. (2016) [1]. Data describes thermogravimetric and dynamical mechanical experiences and provides the figures of weight loss and loss tangent of the films as a function of the temperature. PMID:27158645

  7. Enzymes in Glycolysis and the Citric Acid Cycle in the Yeast and Mycelial Forms of Paracoccidioides brasiliensis

    PubMed Central

    Kanetsuna, Fuminori; Carbonell, Luis M.

    1966-01-01

    Kanetsuna, Fuminori (Instituto Venezolano de Investigaciones Cientificas, Caracas, Venezuela), and Luis M. Carbonell. Enzymes in glycolysis and the citric acid cycle in the yeast and mycelial forms of Paracoccidioides brasiliensis. J. Bacteriol. 92:1315–1320. 1966.—Enzymatic activities in glycolysis, the hexose monophosphate shunt, and the citric acid cycle in cell-free extracts of the yeast and mycelial forms of Paracoccidioides brasiliensis were examined comparatively. Both forms have the enzymes of these pathways. Activities of glucose-6-phosphate dehydrogenase and malic dehydrogenase of the mycelial form were higher than those of the yeast form. Another 15 enzymatic activities of the mycelial form were lower than those of the yeast form. The activity of glyceraldehyde-3-phosphate dehydrogenase showed the most marked difference between the two forms, its activity in the mycelial form being about 20% of that in the yeast form. PMID:5924267

  8. Improved model of the retardance in citric acid coated ferrofluids using stepwise regression

    NASA Astrophysics Data System (ADS)

    Lin, J. F.; Qiu, X. R.

    2017-06-01

    Citric acid (CA) coated Fe3O4 ferrofluids (FFs) have been conducted for biomedical application. The magneto-optical retardance of CA coated FFs was measured by a Stokes polarimeter. Optimization and multiple regression of retardance in FFs were executed by Taguchi method and Microsoft Excel previously, and the F value of regression model was large enough. However, the model executed by Excel was not systematic. Instead we adopted the stepwise regression to model the retardance of CA coated FFs. From the results of stepwise regression by MATLAB, the developed model had highly predictable ability owing to F of 2.55897e+7 and correlation coefficient of one. The average absolute error of predicted retardances to measured retardances was just 0.0044%. Using the genetic algorithm (GA) in MATLAB, the optimized parametric combination was determined as [4.709 0.12 39.998 70.006] corresponding to the pH of suspension, molar ratio of CA to Fe3O4, CA volume, and coating temperature. The maximum retardance was found as 31.712°, close to that obtained by evolutionary solver in Excel and a relative error of -0.013%. Above all, the stepwise regression method was successfully used to model the retardance of CA coated FFs, and the maximum global retardance was determined by the use of GA.

  9. [Adsorption behavior of copper ion and methylene blue on citric acid- esterified wheat straw].

    PubMed

    Sun, Jin; Zhong, Ke-Ding; Feng, Min; Liu, Xing-Yan; Gong, Ren-Min

    2008-03-01

    A cationic adsorbent with carboxyl groups derived from citric acid- esterified wheat straw (EWS) was prepared by the method of solid phase preparation, and a batch experiment was conducted to study the adsorption behaviors of Cu (II) and methylene blue (MB) in aqueous solution on the EWS under conditions of different initial pH, adsorbent dosage, adsorbate concentration, and contact time. The results showed that the maximum adsorption of Cu (II) and MB was obtained when the initial solution pH was > or = 4.0. 96% of Cu (II) in 100 mg x L(-1) Cu solution and 99% of MB in 250 mg x L(-1) dye solution could be removed by > or = 2.0 g x L(-1) of EWS. The adsorption of Cu (II) and MB fitted the Langmuir sorption isothermal model. The maximum removal capacity (Qm) of EWS was 79.37 mg x g(-1) for Cu (II) and 312.50 mg x g(-1) for MB, and the adsorption equilibrium of Cu (II) and MB was reached within 75 min and 5 h, respectively. The adsorption processes of Cu (II) and MB could be described by pseudo-first order and pseudo-second order kinetic functions, respectively.

  10. The viability of a nonenzymatic reductive citric acid cycle - Kinetics and thermochemistry

    USGS Publications Warehouse

    Ross, D.S.

    2007-01-01

    The likelihood of a functioning nonenzymatic reductive citric acid cycle, recently proposed as the precursor to biosynthesis on early Earth, is examined on the basis of the kinetics and thermochemistry of the acetate ??? pyruvate ??? oxaloacetate ??? malate sequence. Using data derived from studies of the Pd-catalyzed phosphinate reduction of carbonyl functions it is shown that the rate of conversion of pyruvate to malate with that system would have been much too slow to have played a role in the early chemistry of life, while naturally occurring reduction systems such as the fayalite-magnetite-quartz and pyrrhotite-pyrite-magnetite mineral assemblages would have provided even slower conversions. It is also shown that the production of pyruvate from acetate is too highly endoergic to be driven by a naturally occurring energy source such as pyrophosphate. It is thus highly doubtful that the cycle can operate at suitable rates without enzymes, and most unlikely that it could have participated in the chemistry leading to life. ?? 2006 Springer Science + Business Media B.V.

  11. Effect of citric acid, tetracycline, and doxycycline on instrumented periodontally involved root surfaces: A SEM study

    PubMed Central

    Chahal, Gurparkash Singh; Chhina, Kamalpreet; Chhabra, Vipin; Bhatnagar, Rakhi; Chahal, Amna

    2014-01-01

    Background: A surface smear layer consisting of organic and inorganic material is formed on the root surface following mechanical instrumentation and may inhibit the formation of new connective tissue attachment to the root surface. Modification of the tooth surface by root conditioning has resulted in improved connective tissue attachment and has advanced the goal of reconstructive periodontal treatment. Aim: The aim of this study was to compare the effects of citric acid, tetracycline, and doxycycline on the instrumented periodontally involved root surfaces in vitro using a scanning electron microscope. Settings and Design: A total of 45 dentin samples obtained from 15 extracted, scaled, and root planed teeth were divided into three groups. Materials and Methods: The root conditioning agents were applied with cotton pellets using the Passive burnishing technique for 5 minutes. The samples were then examined by the scanning electron microscope. Statistical Analysis Used: The statistical analysis was carried out using Statistical Package for Social Sciences (SPSS Inc., Chicago, IL, version 15.0 for Windows). For all quantitative variables means and standard deviations were calculated and compared. For more than two groups ANOVA was applied. For multiple comparisons post hoc tests with Bonferroni correction was used. Results: Upon statistical analysis the root conditioning agents used in this study were found to be effective in removing the smear layer, uncovering and widening the dentin tubules and unmasking the dentin collagen matrix. Conclusion: Tetracycline HCl was found to be the best root conditioner among the three agents used. PMID:24744541

  12. Synergy of a combination of nisin and citric acid against Staphylococcus aureus and Listeria monocytogenes.

    PubMed

    Zhao, Xingchen; Zhen, Zhen; Wang, Xinyang; Guo, Na

    2017-12-01

    Food-borne diseases caused by pathogens, such as Staphylococcus aureus and Listeria monocytogenes, have long attracted attention globally from researchers, food industries, and food safety authorities. Nisin (NS) is the only bacteriocin used worldwide as a generally recognised as safe (GRAS) food preservative, while citric acid (CA) has an unrestricted use in foods since it has GRAS status. In this study, synergistic interactions of NS combined with CA against S. aureus and L. monocytogenes were studied by the chequerboard microdilution method, with fractional inhibitory concentration index values ranging from 0.25 to 0.375 and 0.19 to 0.375, respectively. The positive interactions were verified by time-kill studies in pasteurised milk and disk diffusion assays. The mechanism of the synergistic antibacterial of NS and CA is proposed following SEM analysis and the determination of release of cell constituents. These results suggest that the cell walls and membrane are the probable main targets of this antimicrobial combination. These findings indicated that the combination of NS and CA not only could be used as a new promising naturally sourced food preservative, but may also reduce the problem of bacterial resistance.

  13. Photocatalytic hydrogen production from biomass-derived compounds: a case study of citric acid.

    PubMed

    Alkaim, Ayad F; Kandiel, Tarek A; Dillert, Ralf; Bahnemann, Detlef W

    2016-11-01

    Highly crystalline anatase TiO2 nanoparticles with high BET surface area have been synthesized by thermal hydrolysis of titanium(IV) bis(ammoniumlactato) dihydroxide aqueous solutions. The photocatalytic H2 production from aqueous citric acid (CA) solutions over Pt-loaded TiO2 has been investigated under different experimental conditions, that is, different CA concentration, temperature, light intensity, and pH of Pt/TiO2 suspension. For comparison, the photocatalytic dehydrogenation of triethanolamine (TEA) has also been investigated. The highest H2 production rates were obtained at pH 3 and 9 for CA and TEA, respectively. This behavior is readily explained by the adsorption characteristic of the employed reagent on the surface of the charged TiO2. The effect of the photocatalyst loading and the light intensity on the H2 production rate showed the same behavior in the case of CA and TEA evincing that these parameters are catalyst dependent. The apparent activation energies have been determined to be 13.5 ± 1.8 and 14.7 ± 1.6 kJ mol(-1) for CA and TEA, respectively, indicating the existence of an activation energy barrier in a photocatalytic process which can be attributed to the desorption of adsorbed products.

  14. Teaching about citric acid cycle using plant mitochondrial preparations: Some assays for use in laboratory courses*.

    PubMed

    Vicente, Joaquim A F; Gomes-Santos, Carina S S; Sousa, Ana Paula M; Madeira, Vítor M C

    2005-03-01

    Potato tubers and turnip roots were used to prepare purified mitochondria for laboratory practical work in the teaching of the citric acid cycle (TCA cycle). Plant mitochondria are particularly advantageous over the animal fractions to demonstrate the TCA cycle enzymatic steps, by using simple techniques to measure O(2) consumption and transmembrane potential (ΔΨ). The several TCA cycle intermediates induce specific enzyme activities, which can be identified by respiratory parameters. Such a strategy is also used to evidence properties of the TCA cycle enzymes: ADP stimulation of isocitrate dehydrogenase and α-ketoglutarate dehydrogenase; activation by citrate of downstream oxidation steps, e.g. succinate dehydrogenase; and regulation of the activity of isocitrate dehydrogenase by citrate action on the citrate/isocitrate carrier. Furthermore, it has been demonstrated that, in the absence of exogenous Mg(2+) , isocitrate-dependent respiration favors the alternative oxidase pathway, as judged by changes of the ADP/O elicited by the inhibitor n-propyl galate. These are some examples of assays related with TCA cycle intermediates we can use in laboratory courses. Copyright © 2005 International Union of Biochemistry and Molecular Biology, Inc.

  15. Central Composite Design Optimization of Zinc Removal from Contaminated Soil, Using Citric Acid as Biodegradable Chelant.

    PubMed

    Asadzadeh, Farrokh; Maleki-Kaklar, Mahdi; Soiltanalinejad, Nooshin; Shabani, Farzin

    2018-02-08

    Citric acid (CA) was evaluated in terms of its efficiency as a biodegradable chelating agent, in removing zinc (Zn) from heavily contaminated soil, using a soil washing process. To determine preliminary ranges of variables in the washing process, single factor experiments were carried out with different CA concentrations, pH levels and washing times. Optimization of batch washing conditions followed using a response surface methodology (RSM) based central composite design (CCD) approach. CCD predicted values and experimental results showed strong agreement, with an R 2 value of 0.966. Maximum removal of 92.8% occurred with a CA concentration of 167.6 mM, pH of 4.43, and washing time of 30 min as optimal variable values. A leaching column experiment followed, to examine the efficiency of the optimum conditions established by the CCD model. A comparison of two soil washing techniques indicated that the removal efficiency rate of the column experiment (85.8%) closely matching that of the batch experiment (92.8%). The methodology supporting the research experimentation for optimizing Zn removal may be useful in the design of protocols for practical engineering soil decontamination applications.

  16. Full-scale and laboratory-scale anaerobic treatment of citric acid production wastewater.

    PubMed

    Colleran, E; Pender, S; Philpott, U; O'Flaherty, V; Leahy, B

    1998-01-01

    This paper reviews the operation of a full-scale, fixed-bed digester treating a citric acid production wastewater with a COD:sulphate ratio of 3-4:1. Support matrix pieces were removed from the digester at intervals during the first 5 years of operation in order to quantify the vertical distribution of biomass within the digester. Detailed analysis of the digester biomass after 5 years of operation indicated that H2 and propionate-utilising SRB had outcompeted hydrogenophilic methanogens and propionate syntrophs. Acetoclastic methanogens were shown to play the dominant role in acetate conversion. Butyrate and ethanol-degrading syntrophs also remained active in the digester after 5 years of operation. Laboratory-scale hybrid reactor treatment at 55 degrees C of a diluted molasses influent, with and without sulphate supplementation, showed that the reactors could be operated with high stability at volumetric loading rates of 24 kgCOD.m-3.d-1 (12 h HRT). In the presence of sulphate (2 g/l-1; COD/sulphate ratio of 6:1), acetate conversion was severely inhibited, resulting in effluent acetate concentrations of up to 4000 mg.l-1.

  17. The Viability of a Nonenzymatic Reductive Citric Acid Cycle Kinetics and Thermochemistry

    NASA Astrophysics Data System (ADS)

    Ross, David S.

    2007-02-01

    The likelihood of a functioning nonenzymatic reductive citric acid cycle, recently proposed as the precursor to biosynthesis on early Earth, is examined on the basis of the kinetics and thermochemistry of the acetate → pyruvate → oxaloacetate → malate sequence. Using data derived from studies of the Pd-catalyzed phosphinate reduction of carbonyl functions it is shown that the rate of conversion of pyruvate to malate with that system would have been much too slow to have played a role in the early chemistry of life, while naturally occurring reduction systems such as the fayalite magnetite quartz and pyrrhotite pyrite magnetite mineral assemblages would have provided even slower conversions. It is also shown that the production of pyruvate from acetate is too highly endoergic to be driven by a naturally occurring energy source such as pyrophosphate. It is thus highly doubtful that the cycle can operate at suitable rates without enzymes, and most unlikely that it could have participated in the chemistry leading to life.

  18. Citric acid based durable and sustainable flame retardant treatment for lyocell fabric.

    PubMed

    Mengal, Naveed; Syed, Uzma; Malik, Samander Ali; Ali Sahito, Iftikhar; Jeong, Sung Hoon

    2016-11-20

    Pyrovatex CP New, is a commonly used organophosphorus based flame retardant (FR) reagent for cellulosic materials. However, it has a drawback of high formaldehyde release when used with methylated melamine (MM) based cross-linker, a known carcinogenous compound. In the present approach, a durable and sustainable flame retarding recipe formulation for lyocell fabrics is developed using citric acid (CA) as a cross-linker. The FR finish was applied by pad-dry-cure process. The treated fabrics were characterized for surface morphology, elemental analysis, TG analysis, char study and FT-IR spectroscopy. Furthermore, flame retardancy, washing durability, formaldehyde release and breaking strength were also assessed, and compared with the conventional MM based FR recipe. The fabric samples treated with 400gL(-1) of FR with either 40 or 80gL(-1) of CA demonstrate flame retardancy even after 10 washing cycles. Furthermore, a 75% reduction in formaldehyde release is achieved. Higher char yield and lower decomposition temperature are found compared to untreated and FR+ MM treated lyocell. Such an improved sustainable recipe formulation can be used for lyocell fabric without any health risk in apparel wear. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Coagulation of bitumen with kaolinite in aqueous solutions containing Ca2+, Mg2+ and Fe3+: effect of citric acid.

    PubMed

    Gan, Weibing; Liu, Qi

    2008-08-01

    Heterocoagulation experiments of kaolinite with solvent-diluted-bitumen were carried out to investigate the effect of hydrolyzable metal cations and citric acid on the liberation of bitumen from kaolinite. The adsorption of Ca(2+) and Mg(2+) on kaolinite, and zeta potentials of kaolinite and bitumen droplets in solutions containing 10(-3)mol/L of Ca(2+), Mg(2+) and Fe(3+) with or without citric acid were also measured. It was found that the heterocoagulation of bitumen with kaolinite was enhanced in the presence of the metal cations from pH 7 to pH 10.5, accompanied by a decrease in the magnitude of the zeta potentials and an increase in the adsorption of the metal cations on kaolinite and possibly on bitumen droplets. The addition of 5 x 10(-4)mol/L citric acid reduced the degree of coagulation from 90% to less than 40% in the presence of 10(-3)mol/L Ca(2+) and Mg(2+) cations at pH approximately 10, and at pH approximately 8 for Fe(3+). It was found that hydrolyzable metal cations enhanced bitumen-kaolinite interactions through electrical double layer compression and specific adsorption of the metal hydrolysis species on the surface of kaolinite. The effect of metal cations was removed by citric acid through formation of metal-citrate complexes and/or the adsorption of citrate anions, which restored the zeta potentials of both kaolinite and bitumen. Therefore, electrostatic attraction or repulsion was responsible for the coagulation or dispersion of kaolinite particles from bitumen droplets in the tested system.

  20. The effect of theobromine 200 mg/l topical gel exposure duration against surface enamel hardness resistance from 1% citric acid

    NASA Astrophysics Data System (ADS)

    Herisa, H. M.; Noerdin, A.; Eriwati, Y. K.

    2017-08-01

    Theobromine can be used to prevent the demineralization of enamel and can stimulate the growth of new enamels. This study analyzes the effect of theobromine’s gel duration exposure on enamel hardness resistance from 1% citric acid. Twenty-eight specimens were divided into three experimental groups; were exposed to theobromine gel 200 mg/l for 16, 48, and 96 minutes; and were then immersed in 1% citric acid. The control group was only immersed in 1% citric acid. Results: A Wilcoxon test showed a significant increase and decrease in enamel microhardness after exposure to theobromine gel and citric acid (p < 0.05). A Mann-Whitney test showed a significant increase and decrease in enamel microhardness between different durations of exposure to theobromine gel and immersion in citric acid (p < 0.05). The application of theobromine gel 200mg/L increased enamel microhardness but did not contribute to the enamel’s hardness resistance after immersion in 1% citric acid. The duration of theobromine gel application affected enamel microhardness and acid resistance.

  1. The effect of combination of sugar palm fruit, carrageenan, and citric acid on mechanical properties of biodegradable film

    NASA Astrophysics Data System (ADS)

    Rinanda, S. A.; Nastabiq, M.; Raharjo, S. H.; Hayati, S. K.; Yaqin, M. A.; Ratnawati

    2017-11-01

    Biodegradable film is a type of plastic material that can be degraded naturally and is usually made of organic material. The material commonly used is polysaccharides. The purpose of this study is to observe the effect of the combination of sugar palm fruit, carrageenan, and citric acid (CA) on the mechanical properties of the biodegradable films, such as tensile strength, elongation and film thickness. The experiment begins with dissolving the sugar palm fruit porridge and carrageenan with ratios of 1:0, 3:1, 2:1, 1:1 in water. The mixture was heated using a heater and magnetic stirrer at 80° C for 10 minutes. Glycerol and citric acid (CA) were added to the solution and stirred for 5 minutes. Each film solution was printed on a modified acrylic and, dried for 18 hours in an oven at 55° C. The formed film layer was then removed from the acrylic mold and inserted in a desiccatorsat 23° C for 1 hour. Then the film analyzed for its tensile strength, elongation using Dynamic Mechanical Thermal Analysis (DMTA), and thickness. The optimum result shown by sugar palm fruit and carrageenan ratio of 1:1 with 1% citric acid (CA).

  2. Anti-Inflammatory Activity of Citric Acid-Treated Wheat Germ Extract in Lipopolysaccharide-Stimulated Macrophages.

    PubMed

    Jeong, Hee-Yeong; Choi, Yong-Seok; Lee, Jae-Kang; Lee, Beom-Joon; Kim, Woo-Ki; Kang, Hee

    2017-07-10

    Until recently, fermentation was the only processing used to improve the functionality of wheat germ. The release of 2,6-dimethoxy-1,4-benzoquinone (DMBQ) from hydroquinone glycosides during the fermentation process is considered a marker of quality control. Here, we treated wheat germ extract with citric acid (CWG) to release DMBQ and examined the anti-inflammatory activity of this extract using a lipopolysaccharide-activated macrophage model. Treatment of wheat germ with citric acid resulted in detectable release of DMBQ but reduced total phenolic and total flavonoid contents compared with untreated wheat germ extract (UWG). CWG inhibited secretion of the pro-inflammatory cytokines tumor necrosis factor-α, interleukin (IL)-6, and IL-12 and the synthesis of cyclooxygenase-2, while UWG only decreased IL-12 production. CWG and UWG induced high levels of anti-inflammatory IL-10 and heme oxygenase-1. CWG specifically inhibited phosphorylation of NF-κB p65 and p38 kinase at 15 min after LPS stimulation. Our study showed that citric acid treatment enhanced the anti-inflammatory activity of wheat germ extract.

  3. Citric acid induced promoted dispersion of Pt on the support and enhanced catalytic activities for a Pt-based catalyst

    NASA Astrophysics Data System (ADS)

    Cheng, Tianqiong; Wang, Jianli; Wang, Suning; Cui, Yajuan; Zhang, Hailong; Yan, Shuang; Yuan, Shandong; Chen, Yaoqiang

    2017-12-01

    Citric acid (CA), as the chelating agent, was introduced to obtain the enhanced Pt dispersion and catalytic activities for the Pt-based catalysts supported on oxygen-storage material. The role and content of CA were investigated systematically. It was found that the citric acid-assisted catalysts showed better Pt dispersion and smaller nanoparticle size of Pt. Thus, the catalyst had lower reduction temperature, preferable thermostability and possessed more oxidation state of Pt species under the oxidation atmosphere. The citric acid-induced fresh catalysts were excellent to convert CO and the corresponding aged ones exhibited higher activities for the elimination of all the target pollutants. Among the aged catalysts, P2-a (the mole ratio of Pt/CA is 2:1) presented the best performance. Particularly, compared with the reference sample (Pc-a), the light-off temperatures (T50) of NO, HC and CO for P2-a decreased by 39 °C, 42 °C and 72 °C, respectively, and the full-conversion temperatures (T90) of NO, HC and CO for P2-a decreased by 44 °C, 44 °C and 48 °C, respectively. Therefore, this work provides a facile and valid method to manufacture advanced catalysts for purification of the vehicle exhaust in the future.

  4. Effect of cellulose nanocrystals (CNC) addition and citric acid as co-plasticizer on physical properties of sago starch biocomposite

    NASA Astrophysics Data System (ADS)

    Nasution, Halimatuddahliana; Afandy, Yayang; Al-fath, M. Thoriq

    2018-04-01

    Cellulose has potential applications in new high-performance materials with low environmental impact. Rattan biomass is a fiber waste from processing industry of rattan which contains 37,6% cellulose. The high cellulose contents of rattan biomass make it a source of cellulose nanocrystals as a filler in biocomposite. Isolation of alpha cellulose from biomass rattan was prepared by using three stages: delignification, alkalization, and bleaching. It was delignificated with 3,5% HNO3 and NaNO2, precipitated with 17,5% NaOH, bleaching process with 10% H2O2. Nanocrystals obtained through the hydrolysis of alpha cellulose using 45% H2SO4 and followed by mechanical processes of ultrasonication, centrifugation, and filtration with a dialysis membrane. Sago starch biocomposites were prepared using a solution casting method, which includes 1-4 wt % cellulose nanocrystals rattan biomass as fillers, 10-40 wt% citric acid as co-plasticizer and 30 wt% glycerol as plasticizer. The results of TEM and FTIR characteristic of cellulose nanocrystals show spherical like shape FTIR and chemical composition analysis demonstrated that lignin and hemicellulose structures were successfully removed. Biocomposite characteristic consists of density and water absorption. The results showed the highest density values were 0,266 gram/cm3 obtained at an additional of 3% cellulose nanocrystals rattan biomass and 30% citric acid. The lowest water absorption was 7,893% obtained at an additional of 4% cellulose nanocrystals rattan biomass and 10% citric acid.

  5. Suicide by plastic bag suffocation combined with the mixture of citric acid and baking soda in an adolescent.

    PubMed

    Murakami, Keishu; Kawaguchi, Takashi; Hashizume, Yumiko; Kitamura, Kengo; Okada, Misato; Okumoto, Kohei; Sakamoto, Shoich; Ishida, Yuko; Nosaka, Mizuho; Kimura, Akihiko; Takatsu, Akihiro; Kondo, Toshikazu

    2018-05-22

    We describe a case of suicidal asphyxiation using a plastic bag combined with carbon dioxide (CO 2 ) gas. A 20-year-old male, whose head was covered with a plastic bag, was found dead in his room. In the plastic bag, there were two glass-made cups containing liquid-like substance. Through crime scene investigation by police staffs, a bottle of citric acid and a box of baking soda were also discovered in his room. The forensic autopsy revealed that there were neither lesions nor injuries in all of the organs. Moreover, any drugs and poisons could not be detected in blood samples. Based on autopsy findings and crime scene investigation, the cause of death was diagnosed as acute asphyxia due to CO 2 intoxication by the mixture of citric acid with baking soda in the plastic bag. To the best of our knowledge, there are no medical literatures describing plastic bag suffocation combined with CO 2 gas generated from citric acid and baking soda, which has been widely distributed as suicidal means through websites. This case report promotes forensic pathologists and medical coroners to emphasize that the Internet has a crucial role on a source of suicidal information or a promoter of suicide all over the world.

  6. C-Myc Induced Compensated Cardiac Hypertrophy Increases Free Fatty Acid Utilization for the Citric Acid Cycle

    SciTech Connect

    Olson, Aaron; Ledee, Dolena; Iwamoto, Kate

    The protooncogene C-Myc (Myc) regulates cardiac hypertrophy. Myc promotes compensated cardiac function, suggesting that the operative mechanisms differ from those leading to heart failure. Myc regulation of substrate metabolism is a reasonable target, as Myc alters metabolism in other tissues. We hypothesize that Myc-induced shifts in substrate utilization signal and promote compensated hypertrophy. We used cardiac specific Myc-inducible C57/BL6 male mice between 4-6 months old that develop hypertrophy with tamoxifen (tam). Isolated working hearts and 13Carbon (13C )-NMR were used to measure function and fractional contributions (Fc) to the citric acid cycle by using perfusate containing 13C-labeled free fatty acids,more » acetoacetate, lactate, unlabeled glucose and insulin. Studies were performed at pre-hypertrophy (3-days tam, 3dMyc), established hypertrophy (7-days tam, 7dMyc) or vehicle control (cont). Non-transgenic siblings (NTG) received 7-days tam or vehicle to assess drug effect. Hypertrophy was confirmed by echocardiograms and heart weights. Western blots were performed on key metabolic enzymes. Hypertrophy occurred in 7dMyc only. Cardiac function did not differ between groups. Tam alone did not affect substrate contribution in NTG. Substrate utilization was not significantly altered in 3dMyc versus cont. The free fatty acid FC was significantly greater in 7dMyc vs cont with decreased unlabeled Fc, which is predominately exogenous glucose. Free fatty acid flux to the citric acid cycle increased while lactate flux was diminished in 7dMyc compared to cont. Total protein levels of a panel of key metabolic enzymes were unchanged; however total protein O-GlcNAcylation was increased in 7dMyc. Substrate utilization changes did not precede hypertrophy; therefore they are not the primary signal for cardiac growth in this model. Free fatty acid utilization and oxidation increase at established hypertrophy. Understanding the mechanisms whereby this change

  7. [The matrix effects of organic acid compounds in ICP-MS].

    PubMed

    Nie, Xi-Du; He, Xiao-Mei; Li, Li-Bo; Xie, Hua-Lin

    2007-07-01

    The matrix effects arising from oxalic acid, lactic acid, tartaric acid and citric acid in inductively coupled plasma mass spectrometry (ICP-MS) were investigated. It has been proved that the sensitivity of analytes can be significantly enhanced by adding small amounts of organic acid compounds with adjusted nebulizer gas flow-rate, especially for the elements with ionization potential between 9 and 11 eV. The tartaric acid has higher enhancement effect on the signal intensity of the hard-to-ionize elements than oxalic acid, lactic acid and citric acid. The mechanism of the enhancement was investigated. The method has been used to determine Be, Zn, As, Se, Sb and Hg in water standard reference materials (SRM). The analytical results are very close to the certified values.

  8. Citric acid induces cell-cycle arrest and apoptosis of human immortalized keratinocyte cell line (HaCaT) via caspase- and mitochondrial-dependent signaling pathways.

    PubMed

    Ying, Tsung-Ho; Chen, Chia-Wei; Hsiao, Yu-Ping; Hung, Sung-Jen; Chung, Jing-Gung; Yang, Jen-Hung

    2013-10-01

    Citric acid is an alpha-hydroxyacid (AHA) widely used in cosmetic dermatology and skincare products. However, there is concern regarding its safety for the skin. In this study, we investigated the cytotoxic effects of citric acid on the human keratinocyte cell line HaCaT. HaCaT cells were treated with citric acid at 2.5-12.5 mM for different time periods. Cell-cycle arrest and apoptosis were investigated by 4,6-diamidino-2-phenylindole dihydrochloride (DAPI) staining, flow cytometry, western blot and confocal microscopy. Citric acid not only inhibited proliferation of HaCaT cells in a dose-dependent manner, but also induced apoptosis and cell cycle-arrest at the G2/M phase (before 24 h) and S phase (after 24 h). Citric acid increased the level of Bcl-2-associated X protein (BAX) and reduced the levels of B-cell lymphoma-2 (BCL-2), B-cell lymphoma-extra large (BCL-XL) and activated caspase-9 and caspase-3, which subsequently induced apoptosis via caspase-dependent and caspase-independent pathways. Citric acid also activated death receptors and increased the levels of caspase-8, activated BH3 interacting-domain death agonist (BID) protein, Apoptosis-inducing factor (AIF), and Endonuclease G (EndoG). Therefore, citric acid induces apoptosis through the mitochondrial pathway in the human keratinocyte cell line HaCaT. The study results suggest that citric acid is cytotoxic to HaCaT cells via induction of apoptosis and cell-cycle arrest in vitro.

  9. Feeding corn grain steeped in citric acid modulates rumen fermentation and inflammatory responses in dairy goats.

    PubMed

    Shen, Y Z; Ding, L Y; Chen, L M; Xu, J H; Zhao, R; Yang, W Z; Wang, H R; Wang, M Z

    2018-06-04

    Cereal grains treated with organic acids were proved to increase ruminal resistant starch and can relieve the risk of ruminal acidosis. However, previous study mainly focussed on acid-treated barley, the effects of organic acid-treated corn is still unknown. The objectives of this study were to evaluate whether feeding ground corn steeped in citric acid (CA) would affect ruminal pH and fermentation patterns, milk production and innate immunity responses in dairy goats. Eight ruminally cannulated Saanen dairy goats were used in a crossover designed experiment. Each experimental period was 21 day long including 14 days for adaption to new diet and 7 days for sampling and data collection. The goats were fed high-grain diet contained 30% hay and 70% corn-based concentrate. The corn was steeped either in water (control) or in 0.5% (wt/vol) CA solution for 48 h. Goats fed CA diet showed improved ruminal pH status with greater mean and minimum ruminal pH, and shorter (P<0.05) duration of ruminal pH<5.6 and less area of ruminal pH<5.6, 5.8 and 6.0. Concentration of total volatile fatty acid and molar proportion of propionate were less but the molar proportion of acetate was greater (P<0.05) in goats fed the CA diet than the control diet. Concentration of ruminal lipopolysaccharide (LPS) was lower (P<0.05) and that of lactic acid also tended (P<0.10) to be lower in goats fed CA than the control. Although dry matter intake, actual milk yield, yield and content of milk protein and lactose were not affected, the milk fat content and 4% fat-corrected milk tended (P<0.10) to be greater in goats fed CA diet. For the inflammatory responses, peripheral LPS did not differ, whereas the concentration of LPS binding protein and serum amyloid A tended (P<0.10) to be less in goats fed CA diet. Similarly, goats fed CA diet had less (P<0.05) concentration of haptoglobin and tumour necrosis factor. These results indicated that feeding ground corn treated with CA effectively improved ruminal

  10. Chiral SiO2 and Ag@SiO2 Materials Templated by Complexes Consisting of Comblike Polyethyleneimine and Tartaric Acid.

    PubMed

    Yao, Dong-Dong; Murata, Hiroki; Tsunega, Seiji; Jin, Ren-Hua

    2015-10-26

    A facile avenue to fabricate micrometer-sized chiral (L-, D-) and meso-like (dl-) SiO2 materials with unique structures by using crystalline complexes (cPEI/tart), composed of comblike polyethyleneimine (cPEI) and L-, D-, or dl-tartaric acid, respectively, as catalytic templates is reported. Interestingly, both chiral crystalline complexes appeared as regularly left- and right-twisted bundle structures about 10 μm in length and about 5 μm in diameter, whereas the dl-form occurred as circular structures with about 10 μm diameter. Subsequently, SiO2 @cPEI/tart hybrids with high silica content (>55.0 wt %) were prepared by stirring a mixture containing tetramethoxysilane (TMOS) and the aggregates of the crystalline complexes in water. The chiral SiO2 hybrids and calcined chiral SiO2 showed very strong CD signals and a nanofiber-based morphology on their surface, whereas dl-SiO2 showed no CD activity and a nanosheet-packed disklike shape. Furthermore, metallic silver nanoparticles (Ag NPs) were encapsulated in each silica hybrid to obtain chiral (D and L forms) and meso-like (dl form) Ag@SiO2 composites. Also, the reaction between L-cysteine (Lcys) and these Ag@SiO2 composites was preliminarily investigated. Only chiral L- and D-Ag@SiO2 composites promoted the reaction between Lcys and Ag NPs to produce a molecular [Ag-Lcys]n complex with remarkable exciton chirality, whereas the reaction hardly occurred in the case of meso-like (dl-) Ag@SiO2 composite. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Changes in transcript levels of starch hydrolysis genes and raising citric acid production via carbon ion irradiation mutagenesis of Aspergillus niger.

    PubMed

    Hu, Wei; Li, Wenjian; Chen, Hao; Liu, Jing; Wang, Shuyang; Chen, Jihong

    2017-01-01

    The filamentous ascomycete Aspergillus niger is well known for its ability to accumulate citric acid for the hydrolysis of starchy materials. To improve citric acid productivity, heavy ion beam mutagenesis was utilized to produce mutant A.niger strains with enhanced production of citric acid in this work. It was demonstrated that a mutant HW2 with high concentration of citric acid was isolated after carbon ion irradiation with the energy of 80Mev/μ, which was obvious increase higher than the original strain from liquefied corn starch as a feedstock. More importantly, with the evidence from the expression profiles of key genes and enzyme activity involved in the starch hydrolysis process between original strain and various phenotype mutants, our results confirmed that different transcript levels of key genes involving in starch hydrolysis process between original strain and mutants could be a significant contributor to different citric acid concentration in A.niger, such as, amyR and glaA, which therefore opened a new avenue for constructing genetically engineered A.niger mutants for high-yield citric acid accumulation in the future. As such, this work demonstrated that heavy ion beam mutagenesis presented an efficient alternative strategy to be developed to generate various phenotype microbe species mutants for functional genes research.

  12. Synthesis, characterization and application of lipase-conjugated citric acid-coated magnetic nanoparticles for ester synthesis using waste frying oil.

    PubMed

    Patel, Unisha; Chauhan, Kishor; Gupte, Shilpa

    2018-04-01

    In the present work, magnetic nanoparticles (MNPs) were prepared by chemical precipitation of trivalent and divalent iron ions which were functionalized using citric acid. The bacterial isolate Staphylococcus epidermidis KX781317 was isolated from oil-contaminated site. The isolate produced lipase, which was purified and immobilized on magnetic nanoparticles (MNPs) for ester synthesis from waste frying oil (WFO). The characterization of MNPs employed conventional TEM, XRD and FTIR techniques. TEM analysis of MNPs showed the particle size in the range of 20-50 nm. FTIR spectra revealed the binding of citric acid to Fe 3 O 4 and lipase on citric acid-coated MNPs. The citric acid-coated MNPs and lipase-conjugated citric acid-coated MNPs had similar XRD patterns which indicate MNPs could preserve their magnetic properties. The maximum immobilization efficiency 98.21% of lipase-containing citric acid-coated MNPs was observed at ratio 10:1 of Cit-MNPs:lipase. The pH and temperature optima for lipase conjugated with Cit-MNPs were 7 and 35 °C, respectively. Isobutanol was found to be an effective solvent for ester synthesis and 1:2 ratio of oil:alcohol observed significant for ester formation. The ester formation was determined using TLC and the % yield of ester conversion was calculated. The rate of ester formation is directly proportional to the enzyme load. Formed esters were identified as isobutyl laurate ester and isobutyl myristate ester through GC-MS analysis.

  13. Changes in transcript levels of starch hydrolysis genes and raising citric acid production via carbon ion irradiation mutagenesis of Aspergillus niger

    PubMed Central

    Li, Wenjian; Chen, Hao; Liu, Jing; Wang, Shuyang; Chen, Jihong

    2017-01-01

    The filamentous ascomycete Aspergillus niger is well known for its ability to accumulate citric acid for the hydrolysis of starchy materials. To improve citric acid productivity, heavy ion beam mutagenesis was utilized to produce mutant A.niger strains with enhanced production of citric acid in this work. It was demonstrated that a mutant HW2 with high concentration of citric acid was isolated after carbon ion irradiation with the energy of 80Mev/μ, which was obvious increase higher than the original strain from liquefied corn starch as a feedstock. More importantly, with the evidence from the expression profiles of key genes and enzyme activity involved in the starch hydrolysis process between original strain and various phenotype mutants, our results confirmed that different transcript levels of key genes involving in starch hydrolysis process between original strain and mutants could be a significant contributor to different citric acid concentration in A.niger, such as, amyR and glaA, which therefore opened a new avenue for constructing genetically engineered A.niger mutants for high-yield citric acid accumulation in the future. As such, this work demonstrated that heavy ion beam mutagenesis presented an efficient alternative strategy to be developed to generate various phenotype microbe species mutants for functional genes research. PMID:28650980

  14. Citric-acid preacidification enhanced electrokinetic remediation for removal of chromium from chromium-residue-contaminated soil.

    PubMed

    Meng, Fansheng; Xue, Hao; Wang, Yeyao; Zheng, Binghui; Wang, Juling

    2018-02-01

    Electrokinetic experiments were conducted on chromium-residue-contaminated soils collected from a chemical plant in China. Acidification-electrokinetic remediation technology was proposed in order to solve the problem of removing inefficient with ordinary electrokinetic. The results showed that electrokinetic remediation removal efficiency of chromium from chromium-contaminated soil was significantly enhanced with acidizing pretreatment. The total chromium [Cr(T)] and hexavalent chromium [Cr(VI)] removal rate of the group acidized by citric acid (0.9 mol/L) for 5 days was increased from 6.23% and 19.01% in the acid-free experiments to 26.97% and 77.66% in the acidification-treated experiments, respectively. In addition, part of chromium with the state of carbonate-combined will be converted into water-soluble state through acidification to improve the removal efficiency. Within the appropriate concentration range, the higher concentration of acid was, the more chromium was released. So the removal efficiency of chromium depended on the acid concentration. The citric acid is also a kind of complexing agent, which produced complexation with Cr that was released by the electrokinetic treatment and then enhanced the removal efficiency. The major speciation of chromium that was removed from soils by acidification-electrokinetics remediation was acid-soluble speciation, revivification speciation and oxidation speciation, which reduced biological availability of chromium.

  15. Bio-based methacrylic acid via catalytic decarboxylation of itaconic and citric acids

    USDA-ARS?s Scientific Manuscript database

    Methacrylic acid is an important commodity monomer for the plastics industry that is produced industrially from acetone, hydrogen cyanide and concentrated sulfuric acid via the acetone cyanohydrin (ACH) process. Disadvantages to the ACH process include nonrenewable starting materials, stoichiometric...

  16. New fermentation processes for producing itaconic acid and citric acid for industrial uses

    USDA-ARS?s Scientific Manuscript database

    Itaconic acid is an important industrial chemical that we have produced by fermentation of simple sugars using the yeast Pseudozyma antarctica. Itaconic acid is priced at ~$4 per kg and has an annual market volume of about 15,000 metric tons. Itaconic acid is used in the polymer industry and for m...

  17. Use of acetic and citric acids to inhibit Escherichia coli O157:H7, Salmonella Typhimurium and Staphylococcus aureus in tabbouleh salad.

    PubMed

    Al-Rousan, Walid M; Olaimat, Amin N; Osaili, Tareq M; Al-Nabulsi, Anas A; Ajo, Radwan Y; Holley, Richard A

    2018-08-01

    The objective of the current study was to evaluate the antimicrobial action of different concentrations of acetic (0.3% and 0.4%) or citric (1% and 1.4%) acids and their combinations (1% citric acid plus 0.4% acetic acid and 1.4% citric acid plus 0.3% acetic acid) against Salmonella Typhimurium, Escherichia coli O157:H7 and Staphylococcus aureus in tabbouleh salad stored at 21, 10 and 4 °C. Acetic acid was more inhibitory toward S. Typhimurium and E. coli O157:H7 than citric acid at 21 °C; S. Typhimurium and E. coli O157:H7 cells were not detected in tabbouleh treated with 0.4% acetic acid after 5 and 7 days, respectively. The combined effect of acetic and citric acid was synergistic against S. Typhimurium, and E. coli O157:H7, but not against S. aureus. The combinations of acetic and citric acids reduced S. Typhimurium, and E. coli O157:H7 to below the detection levels after 2 and 3 days at 21 °C, respectively. However, these treatments significantly reduced S. aureus numbers compared to the control at tested temperatures by the end of storage. Acetic and citric acids have the potential to be used in tabbouleh salad to reduce the risk from S. Typhimurium, E. coli O157:H7 and S. aureus. Copyright © 2018. Published by Elsevier Ltd.

  18. Postrigor citric acid enhancement can alter cooked color but not fresh color of dark-cutting beef.

    PubMed

    Stackhouse, R J; Apple, J K; Yancey, J W S; Keys, C A; Johnson, T M; Mehall, L N

    2016-04-01

    In 2 experiments, dark-cutting (DC) beef strip loins were used to test the effects of citric acid-enhancement pH on visual and instrumental color of fresh and cooked steaks. In Exp. 1 and 2, each DC (mean pH = 6.57 and 6.65, respectively) and normal-pH, low USDA Choice (CH; mean pH = 5.48 and 5.51, respectively) strip loin was cut into 2 equal-length sections, and DC sections were injected to 111% of raw section weight with pH 3.5 to 5.0 (Exp. 1) or pH 2.0 to 3.5 (Exp. 2) solutions made by mixing citric acid in either 0.05% orthophosphate (PO) solution or tap water (HO) base solutions (Exp. 1) and 0.5% PO or 0.5% tripolyphosphate solution base solutions (Exp. 2). After enhancement, sections were cut into steaks, which were assigned to either 5 d of simulated retail display or cooked to 71°C for cooked color measurement. Postenhancement pH of DC steaks enhanced with pH 3.5 to 5.0 solutions did not ( ≥ 0.180) differ from that of nonenhanced DC steaks (Exp. 1) but linearly decreased ( < 0.001) as solution pH decreased from 3.5 to 2.0 (Exp. 2). Even though fresh color scores were increased ( < 0.001) by citric acid enhancement over untreated DC steaks during the first 3 d of display, fresh steak color never ( < 0.001) approached that of nonenhanced CH steaks. When compared with nonenhanced DC steaks, enhancement with pH 3.5 to 5.0 solutions received lower cooked color scores, whereas enhancing DC sections with pH 2.5 solutions produced cooked color and degree-of-doneness scores similar ( ≥ 0.113) to those of nonenhanced CH steaks (Exp. 2). Results indicated that the pH of citric acid enhancement solutions, regardless of base solution, were insufficient to improve the fresh color of DC beef; however, enhancement with pH 2.5 citric acid solutions effectively eliminated the persistent red cooked color typically associated with DC beef comparable with that of normal-pH beef.

  19. New multifunctional pharmaceutical excipient in tablet formulation based on citric acid-cyclodextrin polymer.

    PubMed

    Garcia-Fernandez, Maria José; Tabary, Nicolas; Chai, Feng; Cazaux, Frédéric; Blanchemain, Nicolas; Flament, Marie-Pierre; Martel, Bernard

    2016-09-25

    A β-cyclodextrin (β-CD) polymer obtained by crosslinking β-CD with citric acid in its water-insoluble (PCD-I) and soluble (PCD-S) forms was used as a multifunctional direct compression excipient for tablet designing. PCD-I powder was obtained after grinding the solid fraction through a 200μm grid. PCD-S powder was recovered after lyophilization or spray drying of the PCD-S aqueous solutions, eventually followed by a wet granulation step. Both PCD-I and PCD-S powders were characterized, separately and mixed in variable ratios, based on dynamic water vapor sorption, SEM, particle size distribution, tapped density, compressibility, and flowability. PCD-I and spray dried and lyophilized/wet granulated PCD-S, as well as the mixture PCD-I/PCD-S=90/10, presented optimal free flowing characteristics. Then, PCD-I or PCD-S powders - separately or mixed in variable ratios - were used for tablets preparation by direct compression without adding any other excipient (e.g. binder, lubricant, disintegrant etc). As PCD-I decreased, tablets resistance to crushing and disintegration time increased from 15s to 15min (against 30min for β-CD), showing the improved disintegrant functionality of PCD-I, that rapidly swelled once in contact with water. Finally, PCD was force-fed to Sprague-Dawley rats (2g/kg) which were then observed during 14days for any clinical signs of toxicity. Copyright © 2016. Published by Elsevier B.V.

  20. Mast cells in citric acid-induced cough of guinea pigs

    SciTech Connect

    Lai, Y.-L.; Lin, T.-Y.

    2005-01-01

    It was demonstrated previously that mast cells play an important role in citric acid (CA)-induced airway constriction. To investigate the role of mast cells in CA-induced cough, three experiments were carried out in this study. In the first experiment, 59 guinea pigs were employed and we used compound 48/80 to deplete mast cells, cromolyn sodium to stabilize mast cells, MK-886 to inhibit leukotriene synthesis, pyrilamine to antagonize histamine H{sub 1} receptor, methysergide to antagonize serotonin receptor, and indomethacin to inhibit cyclooxygenase. In the second experiment, 56 compound 48/80-pretreated animals were divided into two parts; the first one was used tomore » test the role of exogenous leukotriene (LT) C{sub 4}, while the second one to test the role of exogenous histamine in CA-induced cough. Each animal with one of the above pretreatments was exposed sequentially to saline (baseline) and CA (0.6 M) aerosol, each for 3 min. Then, cough was recorded for 12 min using a barometric body plethysmograph. In the third experiment, the activation of mast cells upon CA inhalation was investigated by determining arterial plasma histamine concentration in 17 animals. Exposure to CA induced a marked increase in cough number. Compound 48/80, cromolyn sodium, MK-886 and pyrilamine, but not indomethacin or methysergide, significantly attenuated CA-induced cough. Injection of LTC{sub 4} or histamine caused a significant increase in CA-induced cough in compound 48/80-pretreated animals. In addition, CA inhalation caused significant increase in plasma histamine concentration, which was blocked by compound 48/80 pretreatment. These results suggest that mast cells play an important role in CA aerosol inhalation-induced cough via perhaps mediators LTs and histamine.« less

  1. Citric Acid Production from Orange Peel Wastes by Solid-State Fermentation

    PubMed Central

    Torrado, Ana María; Cortés, Sandra; Manuel Salgado, José; Max, Belén; Rodríguez, Noelia; Bibbins, Belinda P.; Converti, Attilio; Manuel Domínguez, José

    2011-01-01

    Valencia orange (Citrus sinensis) peel was employed in this work as raw material for the production of citric acid (CA) by solid-state fermentation (SSF) of Aspergillus niger CECT-2090 (ATCC 9142, NRRL 599) in Erlenmeyer flasks. To investigate the effects of the main operating variables, the inoculum concentration was varied in the range 0.5·103 to 0.7·108 spores/g dry orange peel, the bed loading from 1.0 to 4.8 g of dry orange peel (corresponding to 35-80 % of the total volume), and the moisture content between 50 and 100 % of the maximum water retention capacity (MWRC) of the material. Moreover, additional experiments were done adding methanol or water in different proportions and ways. The optimal conditions for CA production revealed to be an inoculum of 0.5·106 spores/g dry orange peel, a bed loading of 1.0 g of dry orange peel, and a humidification pattern of 70 % MWRC at the beginning of the incubation with posterior addition of 0.12 mL H2O/g dry orange peel (corresponding to 3.3 % of the MWRC) every 12 h starting from 62 h. The addition of methanol was detrimental for the CA production. Under these conditions, the SSF ensured an effective specific production of CA (193 mg CA/g dry orange peel), corresponding to yields of product on total initial and consumed sugars (glucose, fructose and sucrose) of 376 and 383 mg CA/g, respectively. These results, which demonstrate the viability of the CA production by SSF from orange peel without addition of other nutrients, could be of interest to possible, future industrial applications. PMID:24031646

  2. Environmental Life Cycle Assessment of marine sediment decontamination by citric acid enhanced-microwave heating.

    PubMed

    Falciglia, Pietro P; Ingrao, Carlo; De Guidi, Guido; Catalfo, Alfio; Finocchiaro, Guglielmo; Farina, Marcello; Liali, Maria; Lorenzano, Giuseppe; Valastro, Gaetano; Vagliasindi, Federico G A

    2018-04-01

    The potential ability of microwave heating (MWH) for the remediation of marine sediments affected by severe hydrocarbon (HC) contamination was investigated. Decontamination effectiveness and environmental sustainability through a comparative Life Cycle Assessment (LCA) were addressed. Main results revealed that the application of a 650-W MWH treatment resulted in a rapid (15min) HC removal. A citric acid (CA) dose of 0.1M led to enhanced-HC removals of 76.9, 96.5 and 99.7% after 5, 10 and 15min of MW irradiation, respectively. The increase in CA dose to 0.2M resulted in a shorter successful remediation time of 10min. The exponential kinetic model adopted showed a good correlation with the experimental data with R 2 values in the 0.913-0.987 range. The nature of the MW treatment was shown to differently influence the HC fraction concentration after the irradiation process. Achieved HC removals in such a short remediation time are hardly possible by other clean-up techniques, making the studied treatment a potential excellent choice. Removal mechanisms, which allowed the enhanced-MWH to operate as a highly effective multi-step technique (pure thermal desorption+chemical washing), undoubtedly represent a key factor in the whole remediation process. The LCA highlighted that the MW technology is the most environmentally sustainable alternative for sediment decontamination applications, with a total damage, which was 75.74% lower than that associated with the EK (0.0503pt). Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Efficacy of sodium hypochlorite, ethylenediaminetetraacetic acid, citric acid and phosphoric acid in calcium hydroxide removal from the root canal: a microscopic cleanliness evaluation.

    PubMed

    da Silva, Juliana Melo; Silveira, Amanda; Santos, Elizandra; Prado, Laiìs; Pessoa, Oscar F

    2011-12-01

    Rooted molars were subjected to standardized canal instrumentation to a master apical file (MAF). The samples were dressed with Ca(OH)(2), and after 7 days, teeth were reopened and Ca(OH)(2) medication was removed by 1 of 4 different experimental procedures: 2.5% sodium hypochlorite (NaOCl) (n = 10); 17% EDTA-T (n = 10); 10% citric acid (n = 10); or 37% phosphoric acid (n = 10). This was followed by reinstrumentation with MAF plus 15 mL saline solution. The roots were prepared for scanning electron microscopic analysis of the cervical, middle, and apical thirds. Statistical analysis was performed with the Kruskal-Wallis test. EDTA-T and phosphoric acid gave the best results in the apical third, with significant statistical differences compared with other groups. NaOCl gave the worst results. Irrigation with 17% EDTA-T and 37% phosphoric acid is more effective than sodium hypochlorite and citric acid in the removal of calcium hydroxide from the apical third. Copyright © 2011 Mosby, Inc. All rights reserved.

  4. The Citrus transcription factor, CitERF13, regulates citric acid accumulation via a protein-protein interaction with the vacuolar proton pump, CitVHA-c4.

    PubMed

    Li, Shao-jia; Yin, Xue-ren; Xie, Xiu-lan; Allan, Andrew C; Ge, Hang; Shen, Shu-ling; Chen, Kun-song

    2016-02-03

    Organic acids are essential to fruit flavor. The vacuolar H(+) transporting adenosine triphosphatase (V-ATPase) plays an important role in organic acid transport and accumulation. However, less is known of V-ATPase interacting proteins and their relationship with organic acid accumulation. The relationship between V-ATPase and citric acid was investigated, using the citrus tangerine varieties 'Ordinary Ponkan (OPK)' and an early maturing mutant 'Zaoshu Ponkan (ZPK)'. Five V-ATPase genes (CitVHA) were predicted as important to citric acid accumulation. Among the genes, CitVHA-c4 was observed, using a yeast two-hybrid screen, to interact at the protein level with an ethylene response factor, CitERF13. This was verified using bimolecular fluorescence complementation assays. A similar interaction was also observed between Arabidopsis AtERF017 (a CitERF13 homolog) and AtVHA-c4 (a CitVHA-c4 homolog). A synergistic effect on citric acid levels was observed between V-ATPase proteins and interacting ERFs when analyzed using transient over-expression in tobacco and Arabidopsis mutants. Furthermore, the transcript abundance of CitERF13 was concomitant with CitVHA-c4. CitERF13 or AtERF017 over-expression leads to significant citric acid accumulation. This accumulation was abolished in an AtVHA-c4 mutant background. ERF-VHA interactions appear to be involved in citric acid accumulation, which was observed in both citrus and Arabidopsis.

  5. Browning inhibition mechanisms by cysteine, ascorbic acid and citric acid, and identifying PPO-catechol-cysteine reaction products.

    PubMed

    Ali, Hussein M; El-Gizawy, Ahmed M; El-Bassiouny, Rawia E I; Saleh, Mahmoud A

    2015-06-01

    The titled compounds were examined as PPO inhibitors and antibrowning agents; their various mechanisms were investigated and discussed. All compounds reduced significantly both the browning process and PPO activity. Browning index gave strong correlation with PPO activity (r(2) = 0.96, n = 19) indicating that the browning process is mainly enzymatic. Ascorbic acid could reduce the formed quinone instantly to the original substrate (catechol) at high concentration (>1.5 %) while at lower concentrations acted as competitive inhibitor (KI = 0.256 ± 0.067 mM). Cysteine, at higher concentrations (≥1.0 %), reacted with the resulted quinone to give a colorless products while at the low concentrations, cysteine worked as competitive inhibitor (KI = 1.113 ± 0.176 mM). Citric acid acted only as PPO non-competitive inhibitor with KI = 2.074 ± 0.363 mM. The products of PPO-catechole-cysteine reaction could be separation and identification by LC-ESI-MS. Results indicated that the product of the enzymatic oxidation of catechol, quinone, undergoes two successive nucleophilic attacks by cysteine thiol group. Cysteine was condensed with the resulted mono and dithiocatechols to form peptide side chains.

  6. Metabolism: Part II. The Tricarboxylic Acid (TCA), Citric Acid, or Krebs Cycle.

    ERIC Educational Resources Information Center

    Bodner, George M.

    1986-01-01

    Differentiates the tricarboxylic acid (TCA) cycle (or Krebs cycle) from glycolysis, and describes the bridge between the two as being the conversion of pyruvate into acetyl coenzyme A. Discusses the eight steps in the TCA cycle, the results of isotopic labeling experiments, and the net effects of the TCA cycle. (TW)

  7. The effect of cellulose nanocrystal (CNC) from rattan biomass as filler and citric acid as co-plasticizer on tensile properties of sago starch biocomposite

    NASA Astrophysics Data System (ADS)

    Nasution, Halimatuddahliana; Harahap, Hamidah; Afandy, Yayang; Fath, M. Thoriq Al

    2017-11-01

    Biocomposite containing cellulose nanocrystals (CNC) from rattan biomass as fillers and citric acid as co-plasticizer. Rattan biomass is a fiber waste from processing industry of rattan which contains 37.6% cellulose. Isolation of alpha cellulose from rattan biomass was prepared by using three stages: delignification, alkalization, and bleaching. It was delignificated with 3.5% HNO3 and NaNO2, precipitated with 17.5% NaOH, bleaching process with 10% H2O2. The preparation of CNC includes acid hydrolysis using 45% H2SO4 and followed by mechanical processes of ultrasonication, centrifugation, and filtration with a dialysis membrane. Biocomposite was prepared using a solution casting method, which includes 1-4 wt % CNC as fillers, 10-40 wt% citric acid as co-plasticizer and 30 wt% glycerol as plasticizer. The results of TGA, SEM and XRD characteristic of CNC show that CNC has low residue mass, rod like and network like shape with crystallinity index 84.46%. Biocomposite characteristic consists of SEM, tensile strength and elongation at break. The resultshows that biocomposites by addition of CNC and citric acid have a smooth surface and homogeneous distribution of fillers. The tensile strength of biocomposites was increased by addition CNC and citric acid. The addition of CNC decreases the elongation at break but by addition of citric acid, the elongation at break was increased.

  8. Phenotypes of gene disruptants in relation to a putative mitochondrial malate-citrate shuttle protein in citric acid-producing Aspergillus niger.

    PubMed

    Kirimura, Kohtaro; Kobayashi, Keiichi; Ueda, Yuka; Hattori, Takasumi

    2016-09-01

    The mitochondrial citrate transport protein (CTP) functions as a malate-citrate shuttle catalyzing the exchange of citrate plus a proton for malate between mitochondria and cytosol across the inner mitochondrial membrane in higher eukaryotic organisms. In this study, for functional analysis, we cloned the gene encoding putative CTP (ctpA) of citric acid-producing Aspergillus niger WU-2223L. The gene ctpA encodes a polypeptide consisting 296 amino acids conserved active residues required for citrate transport function. Only in early-log phase, the ctpA disruptant DCTPA-1 showed growth delay, and the amount of citric acid produced by strain DCTPA-1 was smaller than that by parental strain WU-2223L. These results indicate that the CTPA affects growth and thereby citric acid metabolism of A. niger changes, especially in early-log phase, but not citric acid-producing period. This is the first report showing that disruption of ctpA causes changes of phenotypes in relation to citric acid production in A. niger.

  9. Citric acid assisted phytoextraction of chromium by sunflower; morpho-physiological and biochemical alterations in plants.

    PubMed

    Farid, Mujahid; Ali, Shafaqat; Rizwan, Muhammad; Ali, Qasim; Abbas, Farhat; Bukhari, Syed Asad Hussain; Saeed, Rashid; Wu, Longhua

    2017-11-01

    Soil and water contamination from heavy metals and metalloids is one of the most discussed and burning global issues due to its potential to cause the scarcity of healthy food and safe water. The scientific community is proposing a range of lab and field based physical, chemical and biological solutions to remedy metals and metalloids contaminated soils and water. The present study finds out a possibility of Chromium (Cr) extraction by sunflower from spiked soil under chelating role of citric acid (CA). The sunflower plants were grown under different concentrations of Cr (0, 5, 10 & 20mgkg -1 ) and CA (0, 2.5 & 5mM). Growth, biomass, gas exchange, photosynthesis, electrolyte leakage (EL), reactive oxygen species (ROS; malondialdehyde (MDA), hydrogen peroxide (H 2 O 2 ) and the activities of antioxidant enzymes such as, superoxide dismutase (SOD), guaiacole values peroxidase (POD), ascorbate peroxidase (APX), catalase (CAT) were measured. The results depicted a clear decline in plant height, root length, leaf area, number of leaves and flowers per plant along with fresh and dry biomass of all parts of plant with increasing concentration of Cr in soil. Similar reduction was observed in chlorophyll a and b, total chlorophyll, carotenoids, soluble protein, gas exchange attributes and SPAD. The increasing concentration of Cr also enhanced the Cr uptake and accumulation in plant roots, stem and leaves along with the production of ROS and EL. The activities of antioxidant enzymes increased with increasing Cr concentration from 0 to 10mg, but decreased at 20mgkg -1 soil. The CA application significantly alleviated Cr-induced inhibition of plant growth, biomass, photosynthesis, gas exchange, soluble proteins and SPAD value. Presence of CA also enhanced the activities of all antioxidant enzymes and reduced the production of ROS and EL. The chelating potential of CA increased the concentration and accumulation of Cr in plant roots, stem and leaves. It is concluded that the

  10. Olodaterol Attenuates Citric Acid-Induced Cough in Naïve and Ovalbumin-Sensitized and Challenged Guinea Pigs

    PubMed Central

    Wex, Eva; Bouyssou, Thierry

    2015-01-01

    Excessive coughing is a common feature of airway diseases. Different G-protein coupled receptors, including β2-adrenergic receptors (β2-AR), have been implicated in the molecular mechanisms underlying the cough reflex. However, the potential antitussive property of β2-AR agonists in patients with respiratory disease is a matter of ongoing debate. The aim of our study was to test the efficacy of the long-acting β2-AR agonist olodaterol with regard to its antitussive property in a pre-clinical model of citric acid-induced cough in guinea pigs and to compare the results to different clinically relevant β2-AR agonists. In our study β2-AR agonists were intratracheally administered, as dry powder, into the lungs of naïve or ovalbumin-sensitized guinea pigs 15 minutes prior to induction of cough by exposure to citric acid. Cough events were counted over 15 minutes during the citric acid exposure. Olodaterol dose-dependently inhibited the number of cough events in naïve and even more potently and with a greater maximal efficacy in ovalbumin-sensitized guinea pigs (p < 0.01). Formoterol and salmeterol showed a trend towards reducing cough. On the contrary, indacaterol demonstrated pro-tussive properties as it significantly increased the number of coughs, both in naïve and ovalbumin-sensitized animals (p < 0.001). In conclusion, olodaterol, at doses eliciting bronchodilation, showed antitussive properties in a model of citric acid-induced cough in naïve and ovalbumin-sensitized guinea pigs. This is in agreement with pre-clinical and clinical studies showing antitussive efficacy of β2-AR agonists. Indacaterol increased the number of coughs in this model, which concurs with clinical data where a transient cough has been observed after indacaterol inhalation. While the antitussive properties of β2-AR agonists can be explained by their ability to lead to the cAMP-induced hyperpolarization of the neuron membrane thereby inhibiting sensory nerve activation and the

  11. The Influence of Various Vibration Frequency on Barium Sulfate Scale Formation Of Vibrated Piping System In The Presence Citric Acid

    NASA Astrophysics Data System (ADS)

    Karaman, N.; Mangestiyono, W.; Muryanto, S.; Jamari, J.; Bayuseno, A. P.

    2018-01-01

    In this paper, the influence of vibrated piping system for BaSO4 scale formation was investigated. The vibration frequency and presence of citric acid were independent variables determining the kinetics, mass deposit and polymorph of the crystals. Correspondingly, induction time and mass of scale were obtained during the experiments. The crystalline scale was observed by scanning electron microscopy (SEM) and X-Ray Diffraction (XRD) to investigate the morphology and the phase mineral deposits, respectively. This effect indicated that the increase in vibration frequency promoted the increased deposition rate, while the pure barite with a plate-like morphology was produced in the experiments.

  12. Citric acid production from hydrolysate of pretreated straw cellulose by Yarrowia lipolytica SWJ-1b using batch and fed-batch cultivation.

    PubMed

    Liu, Xiaoyan; Lv, Jinshun; Zhang, Tong; Deng, Yuanfang

    2015-01-01

    In this study, crude cellulase produced by Trichoderma reesei Rut-30 was used to hydrolyze pretreated straw. After the compositions of the hydrolysate of pretreated straw were optimized, the study showed that natural components of pretreated straw without addition of any other components such as (NH4)2SO4, KH2PO4, or Mg(2+) were suitable for citric acid production by Yarrowia lipolytica SWJ-1b, and the optimal ventilatory capacity was 10.0 L/min/L medium. Batch and fed-batch production of citric acid from the hydrolysate of pretreated straw by Yarrowia lipolytica SWJ-1b has been investigated. In the batch cultivation, 25.4 g/L and 26.7 g/L citric acid were yields from glucose and hydrolysate of straw cellulose, respectively, while the cultivation time was 120 hr. In the three-cycle fed-batch cultivation, citric acid (CA) production was increased to 42.4 g/L and the cultivation time was extended to 240 hr. However, iso-citric acid (ICA) yield in fed-batch cultivation (4.0 g/L) was similar to that during the batch cultivation (3.9 g/L), and only 1.6 g/L of reducing sugar was left in the medium at the end of fed-batch cultivation, suggesting that most of the added carbon was used in the cultivation.

  13. Functional and in vitro gastric digestibility of the whey protein hydrogel loaded with nanostructured lipid carriers and gelled via citric acid-mediated crosslinking.

    PubMed

    Hashemi, Behnaz; Madadlou, Ashkan; Salami, Maryam

    2017-12-15

    Nanostructured lipid carriers (NLCs) with mean size of 347nm were fabricated and added into a heat-denatured whey protein solution. The subsequent crosslinking of proteins by citric acid or CaCl 2 resulted in the formation of cold-set hydrogels. Fourier transform infrared spectroscopy (FTIR) proposed formation of more hydrogen bonds in gel due to NLC loading or citric acid-mediated gelation. It was also found based on FITR spectroscopy that citric acid crosslinking disordered whey proteins. Scanning electron microscopy (SEM) imaging showed a non-porous and finely meshed microstructure for the crosslinked gels compared to non-crosslinked counterparts. Crosslinking also increased the firmness and water-holding capacity of gels. In pepsin-free fluid, a strong correlation existed between reduction in gel swellability and digestibility over periods up to 60min due to NLC loading and citric acid gelation. However, in peptic fluid, NLC loading and citric acid crosslinking brought about much higher decrease in digestibility than swellability. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Role of Tartaric Acid in Chemical, Mechanical and Self-Healing Behaviors of a Calcium-Aluminate Cement Blend with Fly Ash F under Steam and Alkali Carbonate Environments at 270°C

    DOE PAGES

    Pyatina, Tatiana; Sugama, Toshifumi

    2017-03-25

    Tartaric acid (TA) changes short-term mechanical behavior and phase composition of sodium-metasilicate activated calcium-aluminate cement blend with fly ash, type F, when used as a set control additive to allow sufficient pumping time for underground well placement. The present work focuses on TA effect on self-healing properties of the blend under steam or alkali carbonate environments at 270°C applicable to geothermal wells. Compressive strength recoveries and cracks sealing were examined to evaluate self-healing of the cement after repeated crush tests followed by two consecutive healing periods of 10 and 5 days at 270°C. Optical and scanning electron microscopes, X-ray diffraction,more » Fourier Transform infrared and EDX measurements along with thermal gravimetric analyses were used to identify phases participating in the healing processes. Samples with 1% mass fraction of TA by weight of blend demonstrated improved strength recoveries and crack plugging properties, especially in alkali carbonate environment. This effect was attributed to silicon-rich (C,N)-A-S-H amorphous phase predominant in TA-modified samples, high-temperature stable zeolite phases along with the formation of tobermorite-type crystals in the presence of tartaric acid.« less

  15. Role of Tartaric Acid in Chemical, Mechanical and Self-Healing Behaviors of a Calcium-Aluminate Cement Blend with Fly Ash F under Steam and Alkali Carbonate Environments at 270°C

    SciTech Connect

    Pyatina, Tatiana; Sugama, Toshifumi

    Tartaric acid (TA) changes short-term mechanical behavior and phase composition of sodium-metasilicate activated calcium-aluminate cement blend with fly ash, type F, when used as a set control additive to allow sufficient pumping time for underground well placement. The present work focuses on TA effect on self-healing properties of the blend under steam or alkali carbonate environments at 270°C applicable to geothermal wells. Compressive strength recoveries and cracks sealing were examined to evaluate self-healing of the cement after repeated crush tests followed by two consecutive healing periods of 10 and 5 days at 270°C. Optical and scanning electron microscopes, X-ray diffraction,more » Fourier Transform infrared and EDX measurements along with thermal gravimetric analyses were used to identify phases participating in the healing processes. Samples with 1% mass fraction of TA by weight of blend demonstrated improved strength recoveries and crack plugging properties, especially in alkali carbonate environment. This effect was attributed to silicon-rich (C,N)-A-S-H amorphous phase predominant in TA-modified samples, high-temperature stable zeolite phases along with the formation of tobermorite-type crystals in the presence of tartaric acid.« less

  16. Role of Tartaric Acid in Chemical, Mechanical and Self-Healing Behaviors of a Calcium-Aluminate Cement Blend with Fly Ash F under Steam and Alkali Carbonate Environments at 270 °C

    PubMed Central

    Pyatina, Tatiana; Sugama, Toshifumi

    2017-01-01

    Tartaric acid (TA) changes short-term mechanical behavior and phase composition of sodium-metasilicate activated calcium-aluminate cement blend with fly ash, type F, when used as a set control additive to allow sufficient pumping time for underground well placement. The present work focuses on TA effect on self-healing properties of the blend under steam or alkali carbonate environments at 270 °C applicable to geothermal wells. Compressive strength recoveries and cracks sealing were examined to evaluate self-healing of the cement after repeated crush tests followed by two consecutive healing periods of 10 and 5 days at 270 °C. Optical and scanning electron microscopes, X-ray diffraction, Fourier Transform infrared and EDX measurements along with thermal gravimetric analyses were used to identify phases participating in the healing processes. Samples with 1% mass fraction of TA by weight of blend demonstrated improved strength recoveries and crack plugging properties, especially in alkali carbonate environment. This effect was attributed to silicon-rich (C,N)-A-S-H amorphous phase predominant in TA-modified samples, high-temperature stable zeolite phases along with the formation of tobermorite-type crystals in the presence of tartaric acid. PMID:28772701

  17. Analytical Method Development and Validation for the Quantification of Acetone and Isopropyl Alcohol in the Tartaric Acid Base Pellets of Dipyridamole Modified Release Capsules by Using Headspace Gas Chromatographic Technique

    PubMed Central

    2018-01-01

    A simple, sensitive, accurate, robust headspace gas chromatographic method was developed for the quantitative determination of acetone and isopropyl alcohol in tartaric acid-based pellets of dipyridamole modified release capsules. The residual solvents acetone and isopropyl alcohol were used in the manufacturing process of the tartaric acid-based pellets of dipyridamole modified release capsules by considering the solubility of the dipyridamole and excipients in the different manufacturing stages. The method was developed and optimized by using fused silica DB-624 (30 m × 0.32 mm × 1.8 µm) column with the flame ionization detector. The method validation was carried out with regard to the guidelines for validation of analytical procedures Q2 demanded by the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH). All the validation characteristics were meeting the acceptance criteria. Hence, the developed and validated method can be applied for the intended routine analysis. PMID:29686931

  18. Analytical Method Development and Validation for the Quantification of Acetone and Isopropyl Alcohol in the Tartaric Acid Base Pellets of Dipyridamole Modified Release Capsules by Using Headspace Gas Chromatographic Technique.

    PubMed

    Valavala, Sriram; Seelam, Nareshvarma; Tondepu, Subbaiah; Jagarlapudi, V Shanmukha Kumar; Sundarmurthy, Vivekanandan

    2018-01-01

    A simple, sensitive, accurate, robust headspace gas chromatographic method was developed for the quantitative determination of acetone and isopropyl alcohol in tartaric acid-based pellets of dipyridamole modified release capsules. The residual solvents acetone and isopropyl alcohol were used in the manufacturing process of the tartaric acid-based pellets of dipyridamole modified release capsules by considering the solubility of the dipyridamole and excipients in the different manufacturing stages. The method was developed and optimized by using fused silica DB-624 (30 m × 0.32 mm × 1.8  µ m) column with the flame ionization detector. The method validation was carried out with regard to the guidelines for validation of analytical procedures Q2 demanded by the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH). All the validation characteristics were meeting the acceptance criteria. Hence, the developed and validated method can be applied for the intended routine analysis.

  19. Effect of citric acid on material properties of ZnGa2O4:Cr3+ nanopowder prepared by sol-gel method

    NASA Astrophysics Data System (ADS)

    Hussen, Megersa K.; Dejene, Francis B.; Gonfa, Girma G.

    2018-05-01

    This paper reports the material properties of Cr3+ (1.0 mol%)-doped ZnGa2O4 nanopowders prepared by citric acid-assisted sol-gel method with metal cations (Zn + Ga) to citric (M:CA) molar ratios of (1:0.5, 1:1, 1:3 and 1:4). The X-ray diffraction (XRD) results show that the synthesized nanoparticles are cubic structured and concentration of citric acid did not affect the structure. The scanning electron microscope (SEM) shows that the increase of the M:CA molar ratio favors the formation of smaller nano particle of ZnGa2O4:Cr3+. The photoluminescence (PL) is found to be maximum for sample with M:CA ratio of 1:1. Further increase in citric acid leads to significant decrease in the PL intensity. Energy-dispersive X-ray spectroscopy (EDS) measurement confirms the presence of the Zn, Ga, O and Cr ions. Ultraviolet-visible (UV-Vis) spectrophotometer measurement shows an increase in reflectance in visible region and the energy band gap was found to decrease with an increase in citric acid molar ratio. The emission spectra, particle size and photoluminescence lifetimes are comparable with reports on bioimaging applications.

  20. Effect of dietary citric acid on the performance and mineral metabolism of broiler.

    PubMed

    Islam, K M S; Schaeublin, H; Wenk, C; Wanner, M; Liesegang, A

    2012-10-01

    The objective of this study was to investigate the effect of dietary citric acid (CA) on the performance and mineral metabolism of broiler chicks. A total of 1720 Ross PM3 broiler chicks (days old) were randomly assigned to four groups (430 in each) and reared for a period of 35 days. The diets of groups 1, 2, 3 and 4 were supplemented with 0%, 0.25%, 0.75% or 1.25% CA by weight respectively. Feed and faeces samples were collected weekly and analysed for acid insoluble ash, calcium (Ca), phosphorus (P) and magnesium (Mg). The pH was measured in feed and faeces. At the age of 28 days, 10 birds from each group were slaughtered; tibiae were collected from each bird for the determination of bone mineral density, total ash, Ca, P, Mg and bone-breaking strength, and blood was collected for the measurement of osteocalcin, serum CrossLaps(®), Ca, P, Mg and 1,25(OH)(2)Vit-D in serum. After finishing the trial on day 37, all chicks were slaughtered by using the approved procedure. Birds that were fed CA diets were heavier (average body weights of 2030, 2079 and 2086 g in the 0.25%, 0.75% and 1.25% CA groups, respectively, relative to the control birds (1986 g). Feed conversion efficiency (weight gain in g per kg of feed intake) was also higher in birds of the CA-fed groups (582, 595 and 587 g/kg feed intake for 0.25%, 0.75% and 1.25% CA respectively), relative to the control birds (565 g/kg feed intake). The digestibility of Ca, P and Mg increased in the CA-fed groups, especially for the diets supplemented with 0.25% and 0.75% CA. Support for finding was also indicated in the results of the analysis of the tibia. At slaughter, the birds had higher carcass weights and higher graded carcasses in the groups that were fed the CA diets. The estimated profit margin was highest for birds fed the diet containing 0.25% CA. Birds of the 0.75% CA group were found to have the second highest estimated profit margin. Addition of CA up to a level of 1.25% of the diet increased performance

  1. Preservation of urine free catecholamines and their free O-methylated metabolites with citric acid as an alternative to hydrochloric acid for LC-MS/MS-based analyses.

    PubMed

    Peitzsch, Mirko; Pelzel, Daniela; Lattke, Peter; Siegert, Gabriele; Eisenhofer, Graeme

    2016-01-01

    Measurements of urinary fractionated metadrenalines provide a useful screening test to diagnose phaeochromocytoma. Stability of these compounds and their parent catecholamines during and after urine collection is crucial to ensure accuracy of the measurements. Stabilisation with hydrochloric acid (HCl) can promote deconjugation of sulphate-conjugated metadrenalines, indicating a need for alternative preservatives. Urine samples with an intrinsically acidic or alkaline pH (5.5-6.9 or 7.1-8.7, respectively) were used to assess stability of free catecholamines and their free O-methylated metabolites over 7 days of room temperature storage. Stabilisation with HCl was compared with ethylenediaminetetraacetic acid/metabisulphite and monobasic citric acid. Catecholamines and metabolites were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Free catecholamines and their O-methylated metabolites were stable in acidic urine samples over 7 days of room temperature storage, independent of the presence or absence of any stabilisation method. In contrast, free catecholamines, but not the free O-methylated metabolites, showed rapid degradation within 24 h and continuing degradation over 7 days in urine samples with an alkaline pH. Adjustment of alkaline urine samples to a pH of 3-5 with HCl or 4.8-5.4 with citric acid completely blocked degradation of catecholamines. Ethylenediaminetetraacetic acid/metabisulphite, although reducing the extent of degradation of catecholamines in alkaline urine, was largely ineffectual as a stabiliser. Citric acid is equally effective as HCl for stabilisation of urinary free catecholamines and minimises hazards associated with use of strong inorganic acids while avoiding deconjugation of sulphate-conjugated metabolites during simultaneous LC-MS/MS measurements of free catecholamines and their free O-methylated metabolites.

  2. Fabrication of Self-Ordered Alumina Films with Large Interpore Distance by Janus Anodization in Citric Acid

    NASA Astrophysics Data System (ADS)

    Ma, Yingjun; Wen, Yihao; Li, Juan; Li, Yuxin; Zhang, Zhiying; Feng, Chenchen; Sun, Runguang

    2016-12-01

    Self-organized porous anodic alumina (PAA) formed by electrochemical anodization have become a fundamental tool to develop various functional nanomaterials. However, it is still a great challenge to break the interpore distance (Dint) limit (500 nm) by using current anodization technologies of mild anodization (MA) and hard anodization (HA). Here, we reported a new anodization mode named “Janus anodization” (JA) to controllably fabricate self-ordered PAA with large Dint at high voltage of 350-400 V. JA naturally occurs as anodizing Al foils in citric acid solution, which possessing both the characteristics of MA and HA. The process can be divided into two stages: I, slow pore nucleation stage similar to MA; II, unequilibrium self-organization process similar to HA. The as-prepared films had the highest modulus (7.0 GPa) and hardness (127.2 GPa) values compared with the alumina obtained by MA and HA. The optical studies showed that the black films have low reflectance (<10 %) in the wavelength range of 250-1500 nm and photoluminescence property. Dint can be tuned between 645-884 nm by controlling citric acid concentration or anodization voltage. JA is a potential technology to efficiently and controllably fabricate microstructured or hybrid micro- and nanostructured materials with novel properties.

  3. Fabrication of Self-Ordered Alumina Films with Large Interpore Distance by Janus Anodization in Citric Acid

    PubMed Central

    Ma, Yingjun; Wen, Yihao; Li, Juan; Li, Yuxin; Zhang, Zhiying; Feng, Chenchen; Sun, Runguang

    2016-01-01

    Self-organized porous anodic alumina (PAA) formed by electrochemical anodization have become a fundamental tool to develop various functional nanomaterials. However, it is still a great challenge to break the interpore distance (Dint) limit (500 nm) by using current anodization technologies of mild anodization (MA) and hard anodization (HA). Here, we reported a new anodization mode named “Janus anodization” (JA) to controllably fabricate self-ordered PAA with large Dint at high voltage of 350–400 V. JA naturally occurs as anodizing Al foils in citric acid solution, which possessing both the characteristics of MA and HA. The process can be divided into two stages: I, slow pore nucleation stage similar to MA; II, unequilibrium self-organization process similar to HA. The as-prepared films had the highest modulus (7.0 GPa) and hardness (127.2 GPa) values compared with the alumina obtained by MA and HA. The optical studies showed that the black films have low reflectance (<10 %) in the wavelength range of 250–1500 nm and photoluminescence property. Dint can be tuned between 645–884 nm by controlling citric acid concentration or anodization voltage. JA is a potential technology to efficiently and controllably fabricate microstructured or hybrid micro- and nanostructured materials with novel properties. PMID:27958365

  4. Application of natural citric acid sources and their role on arsenic removal from drinking water: a green chemistry approach.

    PubMed

    Majumder, Santanu; Nath, Bibhash; Sarkar, Simita; Islam, Sk Mijanul; Bundschuh, Jochen; Chatterjee, Debashis; Hidalgo, Manuela

    2013-11-15

    Solar Oxidation and Removal of Arsenic (SORAS) is a low-cost non-hazardous technique for the removal of arsenic (As) from groundwater. In this study, we tested the efficiency of natural citric acid sources extracted from tomato, lemon and lime to promote SORAS for As removal at the household level. The experiment was conducted in the laboratory using both synthetic solutions and natural groundwater samples collected from As-polluted areas in West Bengal. The role of As/Fe molar ratios and citrate doses on As removal efficiency were checked in synthetic samples. The results demonstrate that tomato juice (as citric acid) was more efficient to remove As from both synthetic (percentage of removal: 78-98%) and natural groundwater (90-97%) samples compared to lemon (61-83% and 79-85%, respectively) and lime (39-69% and 63-70%, respectively) juices. The As/Fe molar ratio and the citrate dose showed an 'optimized central tendency' on As removal. Anti-oxidants, e.g. 'hydroxycinnamates', found in tomato, were shown to have a higher capacity to catalyze SORAS photochemical reactions compared to 'flavanones' found in lemon or lime. The application of this method has several advantages, such as eco- and user- friendliness and affordability at the household level compared to other low-cost techniques. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. Palladium-platinum core-shell electrocatalysts for oxygen reduction reaction prepared with the assistance of citric acid

    DOE PAGES

    Zhang, Lulu; Su, Dong; Zhu, Shangqian; ...

    2016-04-26

    Core–shell structure is a promising alternative to solid platinum (Pt) nanoparticles as electrocatalyst for oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs). A simple method of preparing palladium (Pd)–platinum (Pt) core–shell catalysts (Pd@Pt/C) in a gram-batch was developed with the assistance of citric acid. The Pt shell deposition involves three different pathways: galvanic displacement reaction between Pd atoms and Pt cations, chemical reduction by citric acid, and reduction by negative charges on Pd surfaces. The uniform ultrathin (~0.4 nm) Pt shell was characterized by in situ X-ray diffraction (XRD) and high-angle annular dark-field scanning transmission electron microscopymore » (HAADF-STEM) images combined with electron energy loss spectroscopy (EELS). Compared with state-of-the-art Pt/C, the Pd@Pt/C core–shell catalyst showed 4 times higher Pt mass activity and much better durability upon potential cycling. As a result, both the mass activity and durability were comparable to that of Pd@Pt/C synthesized by a Cu-mediated-Pt-displacement method, which is more complicated and difficult for mass production.« less

  6. The mixture of liquid foam soap, ethanol and citric acid as a new fixative-preservative solution in veterinary anatomy.

    PubMed

    Turan, Erkut; Gules, Ozay; Kilimci, Figen Sevil; Kara, Mehmet Erkut; Dilek, Omer Gurkan; Sabanci, Seyyid Said; Tatar, Musa

    2017-01-01

    The present study investigates the efficiency of liquid foam soap, ethanol, citric acid and benzalkonium chloride as a fixative-preservative solution (a soap-and ethanol-based fixing solution, or SEFS). In this study, ethanol serves as the fixative and preservative, liquid foam soap as the modifying agent, citric acid as the antioxidant and benzalkonium chloride as the disinfectant. The goat cadavers perfused with SEFS (n=8) were evaluated over a period of one year with respect to hardness, colour and odour using objective methods. Colour and hardness were compared between one fresh cadaver and the SEFS-embalmed cadavers. Histological and microbiological examinations were also performed in tissue samples. Additionally, the cadavers were subjectively evaluated after dissection and palpation. The SEFS provided the effectiveness expected over a 1-year embalming period for the animal cadavers. No bacteria or fungi were isolated except for some non-pathogenic Bacillus species. Visible mould was not present on either cadavers or in the surrounding environment. The cadavers maintained an appearance close to their original anatomical appearance, with muscles having good hardness and elasticity for dissection. Copyright © 2016 Elsevier GmbH. All rights reserved.

  7. Evaluation of shrinking core model in leaching process of Pomalaa nickel laterite using citric acid as leachant at atmospheric conditions

    NASA Astrophysics Data System (ADS)

    Wanta, K. C.; Perdana, I.; Petrus, H. T. B. M.

    2016-11-01

    Most of kinetics studies related to leaching process used shrinking core model to describe physical phenomena of the process. Generally, the model was developed in connection with transport and/or reaction of reactant components. In this study, commonly used internal diffusion controlled shrinking core model was evaluated for leaching process of Pomalaa nickel laterite using citric acid as leachant. Particle size was varied at 60-70, 100-120, -200 meshes, while the operating temperature was kept constant at 358 K, citric acid concentration at 0.1 M, pulp density at 20% w/v and the leaching time was for 120 minutes. Simulation results showed that the shrinking core model was inadequate to closely approach the experimental data. Meanwhile, the experimental data indicated that the leaching process was determined by the mobility of product molecules in the ash layer pores. In case of leaching resulting large product molecules, a mathematical model involving steps of reaction and product diffusion might be appropriate to develop.

  8. Palladium-platinum core-shell electrocatalysts for oxygen reduction reaction prepared with the assistance of citric acid

    SciTech Connect

    Zhang, Lulu; Su, Dong; Zhu, Shangqian

    Core–shell structure is a promising alternative to solid platinum (Pt) nanoparticles as electrocatalyst for oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs). A simple method of preparing palladium (Pd)–platinum (Pt) core–shell catalysts (Pd@Pt/C) in a gram-batch was developed with the assistance of citric acid. The Pt shell deposition involves three different pathways: galvanic displacement reaction between Pd atoms and Pt cations, chemical reduction by citric acid, and reduction by negative charges on Pd surfaces. The uniform ultrathin (~0.4 nm) Pt shell was characterized by in situ X-ray diffraction (XRD) and high-angle annular dark-field scanning transmission electron microscopymore » (HAADF-STEM) images combined with electron energy loss spectroscopy (EELS). Compared with state-of-the-art Pt/C, the Pd@Pt/C core–shell catalyst showed 4 times higher Pt mass activity and much better durability upon potential cycling. As a result, both the mass activity and durability were comparable to that of Pd@Pt/C synthesized by a Cu-mediated-Pt-displacement method, which is more complicated and difficult for mass production.« less

  9. Functionalization of yogurts with Agaricus bisporus extracts encapsulated in spray-dried maltodextrin crosslinked with citric acid.

    PubMed

    Francisco, Cristhian R L; Heleno, Sandrina A; Fernandes, Isabel P M; Barreira, João C M; Calhelha, Ricardo C; Barros, Lillian; Gonçalves, Odinei Hess; Ferreira, Isabel C F R; Barreiro, Maria Filomena

    2018-04-15

    Mushroom extracts contain bioactive compounds potentially useful to functionalize foodstuffs. Herein, alcoholic extracts of Agaricus bisporus were studied for their bioactivity and viability as functional ingredients in a food product with high water content (yogurt). Extracts were microencapsulated (to improve their stability and hydrophilicity) by spray-drying, using maltodextrin crosslinked with citric acid as encapsulating material. The effect of thermal treatment (after atomization) on crosslinking and bioactivity of microspheres was tested. The incorporation of free and thermally untreated forms resulted in yogurts with higher initial antioxidant activity (EC 50 values: 214 and 272 mg.mL -1 ) that decreased after 7 days (EC 50 values: 248 and 314 mg.mL -1 ). Contrarily, thermally treated microencapsulated extracts showed higher antioxidant activity after the same period (EC 50 values, 0 days: 106 mg.mL -1 ; 7 days: 48.7 mg.mL -1 ), in result of an effective protection provided by microencapsulation with crosslinked maltodextrin and citric acid. Functionalized yogurts showed an overall maintenance of nutritional properties. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Cassava starch coating and citric acid to preserve quality parameters of fresh-cut "Tommy Atkins" mango.

    PubMed

    Chiumarelli, Marcela; Pereira, Leila M; Ferrari, Cristhiane C; Sarantópoulos, Claire I G L; Hubinger, Miriam D

    2010-06-01

    Combination of citric acid dipping (5 g/L) and cassava starch coating (10 g/L), with and without glycerol (10 g/L), was studied to verify the effectiveness of these treatments to inhibit enzymatic browning, to reduce respiration rate, and to preserve quality parameters of "Tommy Atkins" fresh-cut mangoes during storage at 5 degrees C. Color characteristics (L and C), mechanical properties (stress at failure), weight loss, beta-carotene content, sensory acceptance, and microbial growth of fruits were evaluated during 15 d. The respiration rate of fruit subjected to the treatments was also analyzed. Nontreated fresh-cut mango was used as a control sample. Cassava starch edible coatings and citric acid dipping promoted a decrease in respiration rate of mango slices, with values up to 41% lower than the control fruit. This treatment also promoted better preservation of texture and color characteristics of mangoes and delayed carotenoid formation and browning reactions during storage. Moreover, the treated fruit showed great sensory acceptance by consumers throughout the whole storage period. However, the use of glycerol in the coating formulation was not efficient in the maintenance of quality parameters of fresh-cut mangoes, promoting a higher weight loss of samples, impairing fruit texture characteristics, increasing carotenogenesis, and favoring microbial growth during storage.

  11. Effect of sodium chloride and citric acid on growth and toxin production by A. caviae and A. sobria at moderate and low temperatures.

    PubMed

    Abu-Ghazaleh, B M

    2000-10-01

    The effect of sodium chloride and citric acid on hemolysin and caseinase production by Aeromonas caviae and Aeromonas sobria at 32 degrees C and 5 degrees C was investigated. At 32 degrees C, although both strains were tolerant to 3% NaCl in TSB, the production of caseinase was decreased in the presence of 1-3% NaCl, and the production of hemolysin was abolished by 2-3% NaCl. Citric acid (0.03%) was less effective than NaCl in reducing hemolysin and caseinase production by both strains at 32 degrees C. A combination of low temperature (5 degrees C) and citric acid treatment reduced hemolysin and caseinase production by both strains. A combination of low temperature (5 degrees C) and NaCl (3%) treatment was the most effective procedure in reducing growth and hemolysin and caseinase production by the tested strains.

  12. D-stat culture for studying the metabolic shifts from oxidative metabolism to lipid accumulation and citric acid production in Yarrowia lipolytica.

    PubMed

    Ochoa-Estopier, Abril; Guillouet, Stéphane E

    2014-01-20

    Lipid accumulation in oleaginous yeasts is triggered by nutrient imbalance in the culture medium between the carbon source in excess and the nitrogen source in limiting concentration. However Yarrowia lipolytica when cultivated on glucose as the sole carbon source, mainly produces citric acid upon nitrogen limitation over lipid accumulation (only 5-10% triacylglycerol). Therefore for developing bioprocess for the production of triacylglycerol from renewable carbon source as glucose it is of first importance to control this imbalance in order to avoid citric acid production during TAG accumulation. Using D-stat cultivation system, where the N/C was linearly decreased using a constant change rate we were able to identify the N/C ratio inducing TAG accumulation (0.085NmolCmol(-1)) and citric acid (0.021NmolCmol(-1)). We therefore demonstrated that it was possible to accumulate lipids without excretion citric acid as long as the N/C was within this indicated range. Moreover enzyme specific activities measurement during the D-stat indicated that ATP-citrate lyase, malic enzyme and acetyl-coA carboxylase were strongly induced at the onset of lipid accumulation and showed different patterns when citric acid was excreted. Our results give relevant information for future industrial bioprocess development concerning the production of lipids using renewable carbohydrate substrates as an alternative way to produce synthons for fuel or chemical industry. By controlling the N/C over the fermentation process on glucose Y. lipolytica can accumulate lipids without excreting citric acid. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. Efficacy of citric acid denture cleanser on the Candida albicans biofilm formed on poly(methyl methacrylate): effects on residual biofilm and recolonization process.

    PubMed

    Faot, Fernanda; Cavalcanti, Yuri Wanderley; Mendonça e Bertolini, Martinna de; Pinto, Luciana de Rezende; da Silva, Wander José; Cury, Altair Antoninha Del Bel

    2014-06-23

    It is well known that the use of denture cleansers can reduce Candida albicans biofilm accumulation; however, the efficacy of citric acid denture cleansers is uncertain. In addition, the long-term efficacy of this denture cleanser is not well established, and their effect on residual biofilms is unknown. This in vitro study evaluated the efficacy of citric acid denture cleanser treatment on C. albicans biofilm recolonization on poly(methyl methacrylate) (PMMA) surface. C. albicans biofilms were developed for 72 h on PMMA resin specimens (n = 168), which were randomly assigned to 1 of 3 cleansing treatments (CTs) overnight (8 h). CTs included purified water as a control (CTC) and two experimental groups that used either a 1:5 dilution of citric acid denture cleanser (CT5) or a 1:8 dilution of citric acid denture cleanser (CT8). Residual biofilms adhering to the specimens were collected and quantified at two time points: immediately after CTs (ICT) and after cleaning and residual biofilm recolonization (RT). Residual biofilms were analyzed by quantifying the viable cells (CFU/mL), and biofilm architecture was evaluated by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). Denture cleanser treatments and evaluation periods were considered study factors. Data were analyzed using two-way ANOVA and Tukey's Honestly Significant Difference (HSD) test (α = 0.05). Immediately after treatments, citric acid denture cleansing solutions (CT5 and CT8) reduced the number of viable cells as compared with the control (p < 0.01). However, after 48 h, both CT groups (CT5 and CT8) showed biofilm recolonization (p < 0.01). Residual biofilm recolonization was also detected by CLSM and SEM analysis, which revealed a higher biomass and average biofilm thickness for the CT8 group (p < 0.01). Citric acid denture cleansers can reduce C. albicans biofilm accumulation and cell viability. However, this CT did not prevent biofilm recolonization.

  14. Enhanced citric acid production in aspergillus with inactivated asparagine-linked glycosylation protein 3 (ALG3), and/or increased laeA expression

    SciTech Connect

    Dai, Ziyu; Baker, Scott E.

    Provided herein are fungi, such as Aspergillus niger, having a dolichyl-P-Man:Man(5)GlcNAc(2)-PP-dolichyl mannosyltransferase (Alg3) gene genetic inactivation, increased expression of a loss of aflR expression A (Lae), or both. In some examples, such mutants have several phenotypes, including an increased production of citric acid relative to the parental strain. Methods of using the disclosed fungi to make citric acid are also provided, as are compositions and kits including the disclosed fungi.

  15. Improving clarity and stability of skim milk powder dispersions by dissociation of casein micelles at pH 11.0 and acidification with citric acid.

    PubMed

    Pan, Kang; Zhong, Qixin

    2013-09-25

    Casein micelles in milk cause turbidity and have poor stability at acidic conditions. In this study, skim milk powder dispersions were alkalized to pH 10.0 or 11.0, corresponding to reduced particle mass. In the following acidification with hydrochloric or citric acid, the re-formation of casein particles was observed. The combination of treatment at pH 11.0 and acidification with citric acid resulted in dispersions with the lowest turbidity and smallest particles, which enabled translucent dispersions at pH 5.5-7.0, corresponding to discrete nanoparticles. The concentration of ionic calcium was lower when acidified with citric acid than hydrochloric acid, corresponding to smaller particles with less negative zeta potential. The pH 11.0 treatment followed by acidification with citric acid also resulted in smaller particles than the simple chelating effects (directly implementing sodium citrate). The produced casein nanoparticles with reduced dimensions can be used for beverage and other novel applications.

  16. Process optimization and leaching kinetics of zinc and manganese metals from zinc-carbon and alkaline spent batteries using citric acid reagent

    NASA Astrophysics Data System (ADS)

    Yuliusman; Amiliana, R. A.; Wulandari, P. T.; Huda, M.; Kusumadewi, F. A.

    2018-03-01

    Zn-Carbon and Alkaline spent batteries contains heavy metals, such as zinc and manganese, which can causes environmental problem if not handled properly. Usually the recovery of these metals were done by leaching method using strong acid, but the use of strong acids as leaching reagents can be harmful to the environment. This paper concerns the recovery of Zn and Mn metals from Zn-C and alkaline spent batteries with leaching method using citric acid as the environmental friendly leaching reagent. The leaching conditions using citric acid were optimized and the leaching kinetics of Zn and Mn in citric acid solution was investigated. The leaching of 89.62% Zn and 63.26% Mn was achieved with 1.5 M citric acid, 90°C temperature, and 90 minutes stirring time. Kinetics data for the dissolution of Zn showed the best fit to chemical control shrinking core model, while the diffusion controlled model was suitable for the dissolution of Mn kinetics data. The activation energy of 6.12 and 1.73 kcal/mol was acquired for the leaching of Zn and Mn in the temperature range 60°C-90°C.

  17. The Citrus transcription factor, CitERF13, regulates citric acid accumulation via a protein-protein interaction with the vacuolar proton pump, CitVHA-c4

    PubMed Central

    Li, Shao-jia; Yin, Xue-ren; Xie, Xiu-lan; Allan, Andrew C.; Ge, Hang; Shen, Shu-ling; Chen, Kun-song

    2016-01-01

    Organic acids are essential to fruit flavor. The vacuolar H+ transporting adenosine triphosphatase (V-ATPase) plays an important role in organic acid transport and accumulation. However, less is known of V-ATPase interacting proteins and their relationship with organic acid accumulation. The relationship between V-ATPase and citric acid was investigated, using the citrus tangerine varieties ‘Ordinary Ponkan (OPK)’ and an early maturing mutant ‘Zaoshu Ponkan (ZPK)’. Five V-ATPase genes (CitVHA) were predicted as important to citric acid accumulation. Among the genes, CitVHA-c4 was observed, using a yeast two-hybrid screen, to interact at the protein level with an ethylene response factor, CitERF13. This was verified using bimolecular fluorescence complementation assays. A similar interaction was also observed between Arabidopsis AtERF017 (a CitERF13 homolog) and AtVHA-c4 (a CitVHA-c4 homolog). A synergistic effect on citric acid levels was observed between V-ATPase proteins and interacting ERFs when analyzed using transient over-expression in tobacco and Arabidopsis mutants. Furthermore, the transcript abundance of CitERF13 was concomitant with CitVHA-c4. CitERF13 or AtERF017 over-expression leads to significant citric acid accumulation. This accumulation was abolished in an AtVHA-c4 mutant background. ERF-VHA interactions appear to be involved in citric acid accumulation, which was observed in both citrus and Arabidopsis. PMID:26837571

  18. Synthesis of WO{sub 3} nanoparticles by citric acid-assisted precipitation and evaluation of their photocatalytic properties

    SciTech Connect

    Sánchez-Martínez, D.; Martínez-de la Cruz, A., E-mail: azael70@yahoo.com.mx; López-Cuéllar, E.

    Graphical abstract: Display Omitted Highlights: ► WO{sub 3} nanoparticles were synthesized by a simple citric acid-assisted precipitation. ► WO{sub 3} photocatalyst was able to the partial mineralization of rhB, IC and MO. ► WO{sub 3} can be considered as a photocatalyst active under visible light irradiation. -- Abstract: WO{sub 3} nanoparticles were synthesized by citric acid-assisted precipitation method using a 1:1.5 molar ratio of ammonium paratungstate hydrate (H{sub 42}N{sub 10}O{sub 42}W{sub 12}·xH{sub 2}O):citric acid (C{sub 6}H{sub 8}O{sub 7}). The formation of monoclinic crystal structure of WO{sub 3} at different temperatures was confirmed by X-ray powder diffraction (XRD). The characterization ofmore » the samples synthesized was complemented by transmission electron microscopy (TEM), Brunauer–Emmitt–Teller surface area (BET) and diffuse reflectance spectroscopy (DRS). According to the thermal treatment followed during the synthesis of WO{sub 3}, the morphology of the nanoparticles formed was characterized by rectangular and ovoid shapes. The photocatalytic activity of WO{sub 3} obtained under different experimental conditions was evaluated in the degradation of rhodamine B (rhB), indigo carmine (IC), methyl orange (MO), and Congo red (CR) in aqueous solution under UV and UV–vis radiation. The highest photocatalytic activity was observed in the sample obtained by thermal treatment at 700 °C. In general, the sequence of degradation of the organic dyes was: indigo carmine (IC) > rhodamine B (rhB) > methyl orange (MO) > Congo red (CR). The mineralization degree of organic dyes by WO{sub 3} photocatalysts was determined by total organic carbon analysis (TOC) reaching percentages of mineralization of 82% (rhB), 85% (IC), 28% (MO), and 7% (CR) for 96 h of lamp irradiation.« less

  19. Aerosol Fragmentation Driven by Coupling of Acid-Base and Free-Radical Chemistry in the Heterogeneous Oxidation of Aqueous Citric Acid by OH Radicals.

    PubMed

    Liu, Matthew J; Wiegel, Aaron A; Wilson, Kevin R; Houle, Frances A

    2017-08-10

    A key uncertainty in the heterogeneous oxidation of carboxylic acids by hydroxyl radicals (OH) in aqueous-phase aerosol is how the free-radical reaction pathways might be altered by acid-base chemistry. In particular, if acid-base reactions occur concurrently with acyloxy radical formation and unimolecular decomposition of alkoxy radicals, there is a possibility that differences in reaction pathways impact the partitioning of organic carbon between the gas and aqueous phases. To examine these questions, a kinetic model is developed for the OH-initiated oxidation of citric acid aerosol at high relative humidity. The reaction scheme, containing both free-radical and acid-base elementary reaction steps with physically validated rate coefficients, accurately predicts the experimentally observed molecular composition, particle size, and average elemental composition of the aerosol upon oxidation. The difference between the two reaction channels centers on the reactivity of carboxylic acid groups. Free-radical reactions mainly add functional groups to the carbon skeleton of neutral citric acid, because carboxylic acid moieties deactivate the unimolecular fragmentation of alkoxy radicals. In contrast, the conjugate carboxylate groups originating from acid-base equilibria activate both acyloxy radical formation and carbon-carbon bond scission of alkoxy radicals, leading to the formation of low molecular weight, highly oxidized products such as oxalic and mesoxalic acid. Subsequent hydration of carbonyl groups in the oxidized products increases the aerosol hygroscopicity and accelerates the substantial water uptake and volume growth that accompany oxidation. These results frame the oxidative lifecycle of atmospheric aerosol: it is governed by feedbacks between reactions that first increase the particle oxidation state, then eventually promote water uptake and acid-base chemistry. When coupled to free-radical reactions, acid-base channels lead to formation of low molecular

  20. Citrus CitNAC62 cooperates with CitWRKY1 to participate in citric acid degradation via up-regulation of CitAco3.

    PubMed

    Li, Shao-Jia; Yin, Xue-Ren; Wang, Wen-Li; Liu, Xiao-Fen; Zhang, Bo; Chen, Kun-Song

    2017-06-15

    Citric acid is the predominant organic acid of citrus fruit. Degradation of citric acid occurs during fruit development, influencing fruit acidity. Associations of CitAco3 transcripts and citric acid degradation have been reported for citrus fruit. Here, transient overexpression of CitAco3 significantly reduced the citric acid content of citrus leaves and fruits. Using dual luciferase assays, it was shown that CitNAC62 and CitWRKY1 could transactivate the promoter of CitAco3. Subcellular localization results showed that CitWRKY1 was located in the nucleus and CitNAC62 was not. Yeast two-hybrid analysis and bimolecular fluorescence complementation (BiFC) assays indicated that the two differently located transcription factors could interact with each other. Furthermore, BiFC showed that the protein-protein interaction occurred only in the nucleus, indicating the potential mobility of CitNAC62 in plant cells. A synergistic effect on citrate content was observed between CitNAC62 and CitWRKY1. Transient overexpression of CitNAC62 or CitWRKY1 led to significantly lower citrate content in citrus fruit. The combined expression of CitNAC62 and CitWRKY1 resulted in lower citrate content compared with the expression of CitNAC62 or CitWRKY1 alone. The transcript abundance of CitAco3 was consistent with the citrate content. Thus, we propose that a complex of CitWRKY1 and CitNAC62 contributes to citric acid degradation in citrus fruit, potentially via modulation of CitAco3. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  1. Acetylation of bacterial cellulose catalyzed by citric acid: Use of reaction conditions for tailoring the esterification extent.

    PubMed

    Ávila Ramírez, Jhon Alejandro; Gómez Hoyos, Catalina; Arroyo, Silvana; Cerrutti, Patricia; Foresti, María Laura

    2016-11-20

    Bacterial cellulose (BC) nanoribbons were partially acetylated by a simple direct solvent-free route catalyzed by citric acid. The assay of reaction conditions within chosen intervals (i.e. esterification time (0.5-7h), catalyst content (0.08-1.01mmol/mmol AGU), and temperature (90-140°C)), illustrated the flexibility of the methodology proposed, with reaction variables which can be conveniently manipulated to acetylate BC to the required degree of substitution (DS) within the 0.20-0.73 interval. Within this DS interval, characterization results indicated a surface-only process in which acetylated bacterial cellulose with tunable DS, preserved fibrous structure and increased hydrophobicity could be easily obtained. The feasibility of reusing the catalyst/excess acylant in view of potential scale-up was also illustrated. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. 76 FR 33219 - Citric Acid and Certain Citrate Salts from the People's Republic of China: Preliminary Results of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-08

    ...The Department of Commerce is conducting an administrative review of the countervailing duty order on citric acid and certain citrate salts from the People's Republic of China for the period September 19, 2008, through December 31, 2009. We preliminarily find that RZBC Co., Ltd. (``RZBC Co.''); RZBC Import & Export Co., Ltd. (``RZBC I&E''); RZBC (Juxian) Co., Ltd. (``RZBC Juxian''); and RZBC Group Co., Ltd. (``RZBC Group'') (collectively, ``RZBC''), and Yixing Union Biochemical Co., Ltd. (``Yixing Union Co.) and Yixing Union Cogeneration Co., Ltd. (``Cogeneration'') (collectively, ``Yixing Union'') received countervailable subsidies during the period of review. If these preliminary results are adopted in our final results of this review, we will instruct U.S. Customs and Border Protection to assess countervailing duties as detailed in the ``Preliminary Results of Review'' section of this notice. Interested parties are invited to comment on these preliminary results.

  3. [Effect of citric acid stimulation on salivary alpha-amylase, total protein, salivary flow rate and pH value in Pi deficiency children].

    PubMed

    Yang, Ze-min; Chen, Long-hui; Lin, Jing; Zhang, Min; Yang, Xiao-rong; Chen, Wei-wen

    2015-02-01

    To compare the effect of citric acid stimulation on salivary alpha-amylase (sAA), total protein (TP), salivary flow rate, and pH value between Pi deficiency (PD) children and healthy children, thereby providing evidence for Pi controlling saliva theory. Twenty PD children were recruited, and 29 healthy children were also recruited at the same time. Saliva samples from all subjects were collected before and after citric acid stimulation. The sAA activity and amount, TP contents, salivary flow rate, and pH value were determined and compared. (1) Citric acid stimulation was able to significantly increase salivary flow rate, pH value, sAA activities, sAA specific activity and sAA amount (including glycosylated and non-glycosylated sAA amount) in healthy children (P<0.05), while it could markedly increase salivary flow rate, pH value, and glycosylated sAA levels in PD children (P<0.05); (2) Although there was no statistical difference in determined salivary indices between the two groups (P>0.05), salivary indices except salivary flow rate and glycosylated sAA levels decreased more in PD children. There was statistical difference in sAA activity ratio, sAA specific activity ratio, and the ratio of glycosylated sAA levels between PD children and healthy children (P<0.05). PD children had decreased response to citric acid stimulation.

  4. A zinc, copper and citric acid biocomplex shows promise for control of Xylella fastidiosa subsp. pauca in olive trees in Apulia region (southern Italy)

    USDA-ARS?s Scientific Manuscript database

    The bacterium Xylella fastidiosa subsp. pauca is associated with the “olive quick decline syndrome” in the Apulia region of southern Italy. To investigate control of this phytopathogen, a compound containing zinc and copper complexed with citric-acid hydracids (Dentamet®) was evaluated for in vitro ...

  5. Improving the degradation behavior and in vitro biological property of nano-hydroxyapatite surface- grafted with the assist of citric acid.

    PubMed

    Jiang, Liuyun; Jiang, Lixin; Xiong, Chengdong; Su, Shengpei

    2016-10-01

    To obtain ideal nano-hydroxyapatite(n-HA) filler for poly(lactide-co-glycolide) (PLGA), a new surface-grafting with the assist of citric acid for nano-hydroxyapatite (n-HA) was designed, and the effect of n-HA surface-grafted with or without citric acid on in vitro degradation behavior and cells viability was studied by the experiments of soaking in simulated body fluid (SBF) and incubating with human osteoblast-like cells (MG-63). The change of pH value, tensile strength reduction, the surface deposits, cells attachment and proliferation of samples during the soaking and incubation were investigated by means of pH meter, electromechanical universal tester, scanning electron microscope (SEM) coupled with energy-dispersive spectro-scopy (EDS), fluorescence microscope and MTT method. The results showed that the introduction of citric acid not only delayed the strength reduction during the degradation by inhibiting the detachment of n-HA from PLGA, but also endowed it better cell attachment and proliferation, suggesting that the n-HA surface-grafted with the assist of citric acid was an important bioactive ceramic fillers for PLGA used as bone materials. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Formation of uniform carrot-like Cu31S16-CuInS2 heteronanostructures assisted by citric acid at the oil/aqueous interface.

    PubMed

    Li, Yongjie; Tang, Aiwei; Liu, Zhenyang; Peng, Lan; Yuan, Yi; Shi, Xifeng; Yang, Chunhe; Teng, Feng

    2018-01-07

    A simple two-phase strategy was developed to prepare Cu 31 S 16 -CuInS 2 heterostructures (HNS) at the oil/aqueous interface, in which the In(OH) 3 phase was often obtained in the products due to the reaction between indium ions and hydroxyl ions in the aqueous phase. To prevent the formation of the In(OH) 3 phase, citric acid was incorporated into the aqueous phase to assist in the synthesis of uniform carrot-like Cu 31 S 16 -CuInS 2 semiconductor HNS at the oil/aqueous interface for the first time. By manipulating the dosage of citric acid and Cu/In precursor ratios, the morphology of the Cu 31 S 16 -CuInS 2 HNS could be tailored from mushroom to carrot-like, and the presence of citric acid played a critical role in the synthesis of high-quality Cu 31 S 16 -CuInS 2 HNS, which inhibited the formation of the In(OH) 3 phase due to the formation of the indium(iii)-citric acid complex. The formation mechanism was studied by monitoring the morphology and phase evolution of the Cu 31 S 16 -CuInS 2 HNS with reaction time, which revealed that the Cu 31 S 16 seeds were first formed and then the cation-exchange reaction directed the subsequent anisotropic growth of the Cu 31 S 16 -CuInS 2 HNS.

  7. [Comparative studies on the quantity of fructose and citric acid in the sperm from bulls at different seasons of the year].

    PubMed

    Doĭcheva, M; Stoianov, T; Tunchev, T

    1978-01-01

    The contents of fructose and citric acid in the semen of seven bulls of different ages were examined over a one-year period. The bulls were used as sires in the Artificial Insemination Station. The semen production was within the normal range. In the course of the investigations the temperature and moisture regimes of the air in the barns was optimal for the semen production of the bulls. No statistically significant changes in the amount of fructose and citric acid were established at different average diurnal temperatures and the relative moisture content in the different annual seasons. A marked positive correlation (r = 0.070 +/- 0.04) was observed between the changes in the contents of fructose and citric acid throughout the year. These changes were in an inverse correlation with the number of spermatozoa per mL of semen (r = 0.26 +/- 0.08) and in a moderate one for the citric acid (r = 0.49 +/- 0.06). In the bulls of the Red Dannish cattle there was a statistically significant decrease in the number of spermatozoa and a statistically significant increase in the number of immobile spermatozoa in the winter season.

  8. Chronic fluoxetine treatment directs energy metabolism towards the citric acid cycle and oxidative phosphorylation in rat hippocampal nonsynaptic mitochondria.

    PubMed

    Filipović, Dragana; Costina, Victor; Perić, Ivana; Stanisavljević, Andrijana; Findeisen, Peter

    2017-03-15

    Fluoxetine (Flx) is the principal treatment for depression; however, the precise mechanisms of its actions remain elusive. Our aim was to identify protein expression changes within rat hippocampus regulated by chronic Flx treatment versus vehicle-controls using proteomics. Fluoxetine-hydrohloride (15mg/kg) was administered daily to adult male Wistar rats for 3weeks, and cytosolic and nonsynaptic mitochondrial hippocampal proteomes were analyzed. All differentially expressed proteins were functionally annotated according to biological process and molecular function using Uniprot and Blast2GO. Our comparative study revealed that in cytosolic and nonsynaptic mitochondrial fractions, 60 and 3 proteins respectively, were down-regulated, and 23 and 60 proteins, respectively, were up-regulated. Proteins differentially regulated in cytosolic and nonsynaptic mitochondrial fractions were primarily related to cellular and metabolic processes. Of the identified proteins, the expressions of calretinin and parvalbumine were confirmed. The predominant molecular functions of differentially expressed proteins in both cell hippocampal fractions were binding and catalytic activity. Most differentially expressed proteins in nonsynaptic mitochondria were catalytic enzymes involved in the pyruvate metabolism, citric acid cycle, oxidative phosphorylation, ATP synthesis, ATP transduction and glutamate metabolism. Results indicate that chronic Flx treatment may influence proteins involved in calcium signaling, cytoskeletal structure, chaperone system and stimulates energy metabolism via the upregulation of GAPDH expression in cytoplasm, as well as directing energy metabolism toward the citric acid cycle and oxidative phosphorylation in nonsynaptic mitochondria. This approach provides new insight into the chronic effects of Flx treatment on protein expression in a key brain region associated with stress response and memory. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. L-Malate dehydrogenase activity in the reductive arm of the incomplete citric acid cycle of Nitrosomonas europaea.

    PubMed

    Deutch, Charles E

    2013-11-01

    The autotrophic nitrifying bacterium Nitrosomonas europaea does not synthesize 2-oxoglutarate (α-ketoglutarate) dehydrogenase under aerobic conditions and so has an incomplete citric acid cycle. L-malate (S-malate) dehydrogenase (MDH) from N. europaea was predicted to show similarity to the NADP(+)-dependent enzymes from chloroplasts and was separated from the NAD(+)-dependent proteins from most other bacteria or mitochondria. MDH activity in a soluble fraction from N. europaea ATCC 19718 was measured spectrophotometrically and exhibited simple Michaelis-Menten kinetics. In the reductive direction, activity with NADH increased from pH 6.0 to 8.5 but activity with NADPH was consistently lower and decreased with pH. At pH 7.0, the K m for oxaloacetate was 20 μM; the K m for NADH was 22 μM but that for NADPH was at least 10 times higher. In the oxidative direction, activity with NAD(+) increased with pH but there was very little activity with NADP(+). At pH 7.0, the K m for L-malate was 5 mM and the K m for NAD(+) was 24 μM. The reductive activity was quite insensitive to inhibition by L-malate but the oxidative activity was very sensitive to oxaloacetate. MDH activity was not strongly activated or inhibited by glycolytic or citric acid cycle metabolites, adenine nucleotides, NaCl concentrations, or most metal ions, but increased with temperature up to about 55 °C. The reductive activity was consistently 10-20 times higher than the oxidative activity. These results indicate that the L-malate dehydrogenase in N. europaea is similar to other NAD(+)-dependent MDHs (EC 1.1.1.37) but physiologically adapted for its role in a reductive biosynthetic sequence.

  10. Influences of AMY1 gene copy number and protein expression on salivary alpha-amylase activity before and after citric acid stimulation in splenic asthenia children.

    PubMed

    Yang, Zemin; Lin, Jing; Chen, Longhui; Zhang, Min; Yang, Xiaorong; Chen, Weiwen

    2015-06-01

    To compare the correlations between salivary alpha-amylase (sAA) activity and amylase, alpha 1 (salivary) gene (AMYl) copy number or its gene expression between splenic asthenia and healthy children, and investigate the reasons of attenuated sAA activity ratio before and after citric acid stimulation in splenic asthenia children. Saliva samples from 20 splenic asthenia children and 29 healthy children were collected before and after citric acid stimulation. AMYl copy number, sAA activity, and total sAA and glycosylated sAA contents were determined, and their correlations were analyzed. Although splenic asthenia and healthy children had no differences in AMY1 copy number, splenic asthenia children had positive correlations between AMY1 copy number and sAA activity before or after citric acid stimulation. Splenic asthenia children had a higher sAA glycosylated proportion ratio and glycosylated sAA content ratio, while their total sAA content ratio and sAA activity ratio were lower compared with healthy children. The glycosylated sAA content ratio was higher than the total sAA content ratio in both groups. Splenic asthenia and healthy children had positive correlations between total sAA or glycosylated sAA content and sAA activity. However, the role played by glycosylated sAA content in sAA activity in healthy children increased after citric acid stimulation, while it decreased in splenic asthenia children. Genetic factors like AMY1 copy number variations, and more importantly, sAA glycosylation abnormalities leading to attenuated sAA activity after citric acid stimulation, which were the main reasons of the attenuated sAA activity ratio in splenic asthenia children compared with healthy children.

  11. Effects of surfactants on low-molecular-weight organic acids to wash soil zinc.

    PubMed

    Chen, Yue; Zhang, Shirong; Xu, Xiaoxun; Yao, Ping; Li, Ting; Wang, Guiyin; Gong, Guoshu; Li, Yun; Deng, Ouping

    2016-03-01

    Soil washing is an effective approach to the removal of heavy metals from contaminated soil. In this study, the effects of the surfactants sodium dodecyl sulfate, Triton X-100, and non-ionic polyacrylamide (NPAM) on oxalic acid, tartaric acid, and citric acid used to remove zinc from contaminated soils were investigated. The Zn removal efficiencies of all washing solutions showed a logarithmic increase with acid concentrations from 0.5 to 10.0 g/L, while they decreased as pH increased from 4 to 9. Increasing the reaction time enhanced the effects of surfactants on Zn removal efficiencies by the acids during washing and significantly (P < 0.05) improved the removal under some mixed cases. Oxalic acid suffered antagonistic effects from the three surfactants and seriously damaged soil nutrients during the removal of soil Zn. Notably, the three surfactants caused synergistic effects on tartaric and citric acid during washing, with NPAM leading to an increase in Zn removal by 5.0 g/L citric acid of 10.60 % (P < 0.05) within 2 h. NPAM also alleviated the loss of cation exchange capacity of washed soils and obviously improved soil nitrogen concentrations. Overall, combining citric acid with NPAM offers a promising approach to the removal of zinc from contaminated soil.

  12. Enhanced degradation of trichloroethene by calcium peroxide activated with Fe(III) in the presence of citric acid

    PubMed Central

    ZHANG, Xiang; GU, Xiaogang; LU, Shuguang; MIAO, Zhouwei; XU, Minhui; FU, Xiaori; DANISH, Muhammad; Brusseau, Mark L.; QIU, Zhaofu; SUI, Qian

    2017-01-01

    Trichloroethene (TCE) degradation by Fe(III)-activated calcium peroxide (CP) in the presence of citric acid (CA) in aqueous solution was investigated. The results demonstrated that the presence of CA enhanced TCE degradation significantly by increasing the concentration of soluble Fe(III) and promoting H2O2 generation. The generation of HO• and O2−• in both the CP/Fe(III) and CP/Fe(III)/CA systems was confirmed with chemical probes. The results of radical scavenging tests showed that TCE degradation was due predominantly o direct oxidation by HO•, while O2−• strengthened the generation of HO• by promoting Fe(III) transformation in the CP/Fe(III)/CA system. Acidic pH conditions were favorable for TCE degradation, and the TCE degradation rate decreased with increasing pH. The presence of Cl−, HCO3−, and humic acid (HA) inhibited TCE degradation to different extents for the CP/Fe(III)/CA system. Analysis of Cl− production suggested that TCE degradation in the CP/Fe(III)/CA system occurred through a dechlorination process. In summary, this study provided detailed information for the application of CA-enhanced Fe(III)-activated calcium peroxide for treating TCE contaminated groundwater. PMID:28959499

  13. Efficacy of citric acid denture cleanser on the Candida albicans biofilm formed on poly(methyl methacrylate): effects on residual biofilm and recolonization process

    PubMed Central

    2014-01-01

    Background It is well known that the use of denture cleansers can reduce Candida albicans biofilm accumulation; however, the efficacy of citric acid denture cleansers is uncertain. In addition, the long-term efficacy of this denture cleanser is not well established, and their effect on residual biofilms is unknown. This in vitro study evaluated the efficacy of citric acid denture cleanser treatment on C. albicans biofilm recolonization on poly(methyl methacrylate) (PMMA) surface. Methods C. albicans biofilms were developed for 72 h on PMMA resin specimens (n = 168), which were randomly assigned to 1 of 3 cleansing treatments (CTs) overnight (8 h). CTs included purified water as a control (CTC) and two experimental groups that used either a 1:5 dilution of citric acid denture cleanser (CT5) or a 1:8 dilution of citric acid denture cleanser (CT8). Residual biofilms adhering to the specimens were collected and quantified at two time points: immediately after CTs (ICT) and after cleaning and residual biofilm recolonization (RT). Residual biofilms were analyzed by quantifying the viable cells (CFU/mL), and biofilm architecture was evaluated by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). Denture cleanser treatments and evaluation periods were considered study factors. Data were analyzed using two-way ANOVA and Tukey’s Honestly Significant Difference (HSD) test (α = 0.05). Results Immediately after treatments, citric acid denture cleansing solutions (CT5 and CT8) reduced the number of viable cells as compared with the control (p < 0.01). However, after 48 h, both CT groups (CT5 and CT8) showed biofilm recolonization (p < 0.01). Residual biofilm recolonization was also detected by CLSM and SEM analysis, which revealed a higher biomass and average biofilm thickness for the CT8 group (p < 0.01). Conclusion Citric acid denture cleansers can reduce C. albicans biofilm accumulation and cell viability. However, this

  14. Bioremediation of arsenic from water with citric acid cross-linked water hyacinth (E. crassipes) root powder.

    PubMed

    Gogoi, Pankaj; Adhikari, Pooja; Maji, Tarun K

    2017-08-01

    A green and novel approach was demonstrated for successful remediation of arsenic from contaminated water by citric acid (CA) cross-linked water hyacinth root powder (RP). Different analytical techniques were used to investigate the binding and structural properties of prepared materials. Titanium dioxide played a significant role in the cross-linking process. Incorporation of CA into RP enhanced its integrity, and thus removal efficiency remained unaffected after several cyclic runs. Also the turbidity which formed due to treatment with uncross-linked RP was reduced to below the permissible limit. Effect of the amount of CA, material dose, treatment time, initial ion concentration, and pH were investigated. Use of 10% (w/w) CA was found to be sufficient to bring down the turbidity of the treated water below 2.5 nephelometric turbidity unit (NTU) without hampering the removal capacity/rate. A material dose of 5 g/L removed successfully total inorganic arsenic concentration to below 10 μg/L. The sorption process could be reasonably explained by Langmuir isotherm, and the maximum adsorption capacity was found to be 28 μg of arsenic/g. The material was found to be more efficient at acidic pH (pH ZPC  = 6.72). The sorption process was governed by a pseudo-second-order kinetic model.

  15. The effect of EDTA and citric acid on phytoremediation of Cd, Cr, and Ni from soil using Helianthus annuus.

    PubMed

    Turgut, Cafer; Katie Pepe, M; Cutright, Teresa J

    2004-09-01

    The possibility to clean heavy metal contaminated soils with hyperaccumulator plants has shown great potential. One of the most recently studied species used in phytoremediation applications are sunflowers. In this study, two cultivars of Helianthus annuus were used in conjunction with ethylene diamine tetracetic acid (EDTA) and citric acid (CA) as chelators. Two different concentrations of the chelators were studied for enhancing the uptake and translocation of Cd, Cr, and Ni from a silty-clay loam soil. When 1.0 g/kg CA was used, the highest total metal uptake was only 0.65 mg. Increasing the CA concentration posed a severe phytotoxicity to both cultivars as evidenced by stunted growth and diminished uptake rates. Decreasing the CA concentration to 0.1 and 0.3 g/kg yielded results that were not statistically different from the control. EDTA at a concentration of 0.1 g/kg yielded the best results for both cultivars achieving a total metal uptake of approximately 0.73 mg compared to approximately 0.40 mg when EDTA was present at 0.3 g/kg.

  16. Comparative leaching of six toxic metals from raw and chemically stabilized MSWI fly ash using citric acid.

    PubMed

    Wang, Huawei; Fan, Xinxiu; Wang, Ya-Nan; Li, Weihua; Sun, Yingjie; Zhan, Meili; Wu, Guizhi

    2018-02-15

    The leaching behavior of six typical toxic metals (Pb, Zn, Cr, Cd, Cu and Ni) from raw and chemically stabilized (phosphate and chelating agent) municipal solid waste incineration (MSWI) fly ash were investigated using citric acid. Leaching tests indicated that phosphate stabilization can effectively decrease the leaching of Zn, Cd and Cr; whereas chelating agent stabilization shows a strong ability to lower the release of Pb, Cd and Cu, but instead increases the solubility of Zn and Cr at low pH conditions. Sequential extraction results suggested that the leaching of Pb, Zn and Cd in both the stabilized MSWI fly ash samples led to the decrease in Fe/Mn oxide fraction and the increase in exchangeable and carbonate fractions. The leaching of Cr was due to the decrease in exchangeable, carbonate and Fe/Mn oxide fractions in phosphate-stabilized and chelating agent-stabilized MSWI fly ash. The leaching of Cu in both stabilized MSWI fly ash was greatly ascribed to the decrease in Fe/Mn oxide and oxidisable fractions. Moreover, predicted curves by geochemical model indicated that both stabilized MSWI fly ash have the risk of releasing toxic metals under strong acid environment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Evaluation of citric acid and GDL in the recovery at different pH levels of Clostridium sporogenes PA 3679 spores subjected to HTST treatment conditions.

    PubMed

    Silla Santos, M H; Torres Zarzo, J

    1996-04-01

    Spores of Clostridium sporogenes PA 3679 were treated at different temperatures (121, 126, 130 and 135 degrees C) in white asparagus purée (pH 5.8) and acidified with glucono-delta-lactone (GDL) and citric acid to pH levels of 5.5, 5.0 and 4.5. Afterwards, the spores were recovered in MPA3679 medium in various conditions: unacidified (pH 7.5), acidified with GDL (500 ppm) and acidified with citric acid (500 and 250 ppm) to pH levels of 6.5, 6.0 and 5.0. The results indicated that the pH levels, concentration and type of acid used act synergistically rather than independently. Citric acid has a stronger inhibiting effect than GDL on the recovery of C. sporogenes PA 3679 spores. At the higher heat treatments (130 and 135 degrees C) the major injury on the spores sensitize more than against the acids and low pH values.

  18. Foliar sprays of citric acid and salicylic acid alter the pattern of root acquisition of some minerals in sweet basil (Ocimum basilicum L.)

    PubMed Central

    Ghazijahani, Noushin; Hadavi, Ebrahim; Jeong, Byoung R.

    2014-01-01

    The effect of foliar application of two levels of citric acid (CA; 0 and 7 mM) and two levels of salicylic acid (SA; 0 and 1 mM) combined with two levels of nutrient solution strength (full strength and half strength) on mineral acquisition by sweet basil were investigated. The experiment was conducted in a randomized block design arrangement with three replications. SA alone reduced the plant height and thickened the stem. Plants supplied with a full strength solution had a ticker stem, produced more biomass, and showed higher values of Fv/Fm. Some changes in the uptake pattern of some nutrients, especially boron and sulfur, were noticed. Higher boron concentrations in leaves were in plants sprayed with a combination of 7 mM CA and 1 mM of SA. Applying combination of CA and SA was more effective than using them individually that suggests an effective synergism between them. PMID:25400645

  19. Structure, Morphology and Optical Properties of TiO2 Films Formed by Anodizing in a Mixed Solution of Citric Acid and Sulfamic Acid

    NASA Astrophysics Data System (ADS)

    Choudhary, R. K.; Sarkar, P.; Biswas, A.; Mishra, P.; Abraham, G. J.; Sastry, P. U.; Kain, V.

    2017-08-01

    TiO2 films of 50-180 nm thickness were formed at room temperature by anodization of titanium metal in a mixture of citric acid and sulfamic acid in the potential range of 5-30 V. The films so obtained were characterized for their crystal structure, surface morphology, chemical composition and optical properties. Grazing incidence x-ray diffraction and micro-laser Raman spectroscopy measurements of the anodic films confirmed the formation of brookite phase of TiO2 at anodizing potentials of 15, 20, 25 and 30 V and amorphous structure at 5 and 10 V. Field emission scanning electron microscopy revealed non-porous microstructure of the films. Spectroscopic ellipsometry measurements evaluated the band gap of TiO2 at around 3.3 eV, whereas the refractive index of the films was found to be in the range of 2-2.35, in the visible range of spectrum.

  20. Glucono-delta-lactone and citric acid as acidulants for lowering the heat resistance of Clostridium sporogenes PA 3679 in HTST working conditions.

    PubMed

    Silla Santos, M H; Torres Zarzo, J

    1995-04-01

    The heat resistance of Clostridium sporogenes PA 3679 spores has been studied to establish the influence of acidification with glucono-delta-lactone (GDL) and citric acid on the thermal resistance parameters (DT and z) of this microorganism and to compare their effect with phosphate buffer and natural asparagus as reference substrates. A reduction in DT values was observed in asparagus purée as the acidification level increased with both acidulants although this effect was more evident at the lower treatment temperatures studied (121-127 degrees C). Citric acid was more effective for reducing the heat resistance of spores than GDL at all of the temperatures. The reduction in pH diminished the value of the z parameter, although it was necessary to lower the pH to 4.5 to obtain a significant reduction.

  1. Geochemical roots of autotrophic carbon fixation: hydrothermal experiments in the system citric acid, H 2O-(±FeS)-(±NiS)

    NASA Astrophysics Data System (ADS)

    Cody, G. D.; Boctor, N. Z.; Hazen, R. M.; Brandes, J. A.; Morowitz, Harold J.; Yoder, H. S.

    2001-10-01

    Recent theories have proposed that life arose from primitive hydrothermal environments employing chemical reactions analogous to the reductive citrate cycle (RCC) as the primary pathway for carbon fixation. This chemistry is presumed to have developed as a natural consequence of the intrinsic geochemistry of the young, prebiotic, Earth. There has been no experimental evidence, however, demonstrating that there exists a natural pathway into such a cycle. Toward this end, the results of hydrothermal experiments involving citric acid are used as a method of deducing such a pathway. Homocatalytic reactions observed in the citric acid-H2O experiments encompass many of the reactions found in modern metabolic systems, i.e., hydration-dehydration, retro-Aldol, decarboxylation, hydrogenation, and isomerization reactions. Three principal decomposition pathways operate to degrade citric acid under thermal and aquathermal conditions. It is concluded that the acid catalyzed βγ decarboxylation pathway, leading ultimately to propene and CO2, may provide the most promise for reaction network reversal under natural hydrothermal conditions. Increased pressure is shown to accelerate the principal decarboxylation reactions under strictly hydrothermal conditions. The effect of forcing the pH via the addition of NaOH reveals that the βγ decarboxylation pathway operates even up to intermediate pH levels. The potential for network reversal (the conversion of propene and CO2 up to a tricarboxylic acid) is demonstrated via the Koch (hydrocarboxylation) reaction promoted heterocatalytically with NiS in the presence of a source of CO. Specifically, an olefin (1-nonene) is converted to a monocarboxylic acid; methacrylic acid is converted to the dicarboxylic acid, methylsuccinic acid; and the dicarboxylic acid, itaconic acid, is converted into the tricarboxylic acid, hydroaconitic acid. A number of interesting sulfur-containing products are also formed that may provide for additional

  2. Effect of pulp density and particle size on indirect bioleaching of Pomalaa nickel laterite using metabolic citric acid

    NASA Astrophysics Data System (ADS)

    Petrus, H. B. T. M.; Wanta, K. C.; Setiawan, H.; Perdana, I.; Astuti, W.

    2018-01-01

    Nickel laterite ore contains oxide of iron, aluminum or both with nickel, cobalt and chromium which can be leached out using hydrometallurgical process. For the purpose of meeting the world’s increasing demand of nickel, there is a need to invent environmentally friendly process to efficiently leach nickel. This experiment used nickel laterite ore obtained from Pomalaa, South Sulawesi. The leaching agent is metabolic citric acid produced by Aspergillus niger under optimum condition. Leaching process was done in three-necked flask in atmospheric temperature and constant stirring speed of 200 rpm. The variable examined in the experiment was pulp density and particle size of nickel laterite ore. Samples were taken at 3, 7, 10, 14, and 17 minutes and then filtered and diluted to be analyzed using ICP-AES. The result of the experiment showed the maximum recovery of metals increase with the decrease of the pulp density. The maximum recovery for varying pulp density were at 5% solid/liquid ratio and the recovery were Ni at 1.63%, Al at 0.47%, Fe at 0.23% and Mg at 1.09%. The effect of particle size on leaching process showed that the leaching process follows the shrinking core model. The maximum recovery of metals at particle size were at 100-120 mesh with Ni at 1.37%, Fe at 0.10%, Al at 0.72% and Mg at 0.62%.

  3. Enhanced adsorption of methylene blue by citric acid modification of biochar derived from water hyacinth (Eichornia crassipes).

    PubMed

    Xu, Yan; Liu, Yunguo; Liu, Shaobo; Tan, Xiaofei; Zeng, Guangming; Zeng, Wei; Ding, Yang; Cao, Weicheng; Zheng, Bohong

    2016-12-01

    In this work, a novel potential adsorbent, citric acid (CA)-modified biochar, named as CAWB, was obtained from water hyacinth biomass by slow pyrolysis in a N 2 environment at 300 °C. The CA modification focused on enhancing the contaminants adsorption capacity of biochar pyrolyzed at relatively low temperature. Over 90 % of the total methylene blue (MB) could be removed at the first 60 min by CAWB, and the maximum MB adsorption capacity could reach to 395 mg g -1 . The physicochemical properties of CAWB was examined by FTIR, XPS, SEM, and BET analysis. The results indicated that the additional carboxyl groups were introduced to the surface of CAWB via the esterification reaction with CA, which played a significant role in the adsorption of MB. Batch adsorption studies showed that the initial MB concentration, solution pH, background ionic strength, and temperature could affect the removal efficiency obviously. The adsorption process could be well described by the pseudo-second-order kinetic model and Langmuir isotherm. Thermodynamic analysis revealed that the MB adsorption onto CAWB was an endothermic and spontaneous process. The regeneration study revealed that CAWB still exhibited an excellent regeneration and adsorption performance after multiple cycle adsorptions. The adsorption experiments of actual dye wastewater by CAWB suggested that it had a great potential in environmental application.

  4. Remediation of cadmium- and lead-contaminated agricultural soil by composite washing with chlorides and citric acid.

    PubMed

    Li, Yu-jiao; Hu, Peng-jie; Zhao, Jie; Dong, Chang-xun

    2015-04-01

    Composite washing of cadmium (Cd)- and lead (Pb)-contaminated agricultural soil from Hunan province in China using mixtures of chlorides (FeCl3, CaCl2) and citric acid (CA) was investigated. The concentrations of composite washing agents for metal removal were optimized. Sequential extraction was conducted to study the changes in metal fractions after soil washing. The removal of two metals at optimum concentration was reached. Using FeCl3 mixed with CA, 44% of Cd and 23% of Pb were removed, and 49 and 32% by CaCl2 mixed with CA, respectively. The mechanism of composite washing was postulated. A mixture of chlorides and CA enhanced metal extraction from soil through the formation of metal-chloride and metal-citrate complexes. CA in extract solutions promoted the formation of metal-chloride complexes and reduced the solution pH. Composite washing reduced Cd and Pb in Fe-Mn oxide forms significantly. Chlorides and CA exerted a synergistic effect on metal extraction during composite washing.

  5. Y2O3:Eu phosphor particles prepared by spray pyrolysis from a solution containing citric acid and polyethylene glycol

    NASA Astrophysics Data System (ADS)

    Roh, H. S.; Kang, Y. C.; Park, H. D.; Park, S. B.

    Y2O3:Eu phosphor particles were prepared by large-scale spray pyrolysis. The morphological control of Y2O3:Eu particles in spray pyrolysis was attempted by adding polymeric precursors to the spray solution. The effect of composition and amount of polymeric precursors on the morphology, crystallinity and photoluminescence characteristics of Y2O3:Eu particles was investigated. Particles prepared from a solution containing polyethylene glycol (PEG) with an average molecular weight of 200 had a hollow structure, while those prepared from solutions containing adequate amounts of citric acid (CA) and PEG had a spherical shape, filled morphology and clean surfaces after post-treatment at high temperature. Y2O3:Eu particles prepared from an aqueous solution with no polymeric precursors had a hollow structure and rough surfaces after post-treatment. The phosphor particles prepared from solutions with inadequate amounts of CA and/or PEG also had hollow and/or fragmented structures. The particles prepared from the solution containing 0.3 M CA and 0.3 M PEG had the highest photoluminescence emission intensity, which was 56% higher than that of the particles prepared from aqueous solution without polymeric precursors.

  6. Citric acid improves lead (pb) phytoextraction in brassica napus L. by mitigating pb-induced morphological and biochemical damages.

    PubMed

    Shakoor, Muhammad Bilal; Ali, Shafaqat; Hameed, Amjad; Farid, Mujahid; Hussain, Sabir; Yasmeen, Tahira; Najeeb, Ullah; Bharwana, Saima Aslam; Abbasi, Ghulam Hasan

    2014-11-01

    Phytoextraction is an environmentally friendly and a cost-effective strategy for remediation of heavy metal contaminated soils. However, lower bioavailability of some of the metals in polluted environments e.g. lead (Pb) is a major constraint of phytoextraction process that could be overcome by applying organic chelators. We conducted a glasshouse experiment to evaluate the role of citric acid (CA) in enhancing Pb phytoextraction. Brassica napus L. seedlings were grown in hydroponic media and exposed to various treatments of Pb (50 and 100 μM) as alone or in combination with CA (2.5mM) for six weeks. Pb-induced damage in B. napus toxicity was evident from elevated levels of malondialdehyde (MDA) and H2O2 that significantly inhibited plant growth, biomass accumulation, leaf chlorophyll contents and gas exchange parameters. Alternatively, CA application to Pb-stressed B. napus plants arrested lipid membrane damage by limiting MDA and H2O2 production and by improving antioxidant enzyme activities. In addition, CA significantly increased the Pb accumulation in B. napus plants. The study concludes that CA has a potential to improve Pb phytoextraction without damaging plant growth. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. Determining soil enzyme activities for the assessment of fungi and citric acid-assisted phytoextraction under cadmium and lead contamination.

    PubMed

    Mao, Liang; Tang, Dong; Feng, Haiwei; Gao, Yang; Zhou, Pei; Xu, Lurong; Wang, Lumei

    2015-12-01

    Microorganism or chelate-assisted phytoextraction is an effective remediation tool for heavy metal polluted soil, but investigations into its impact on soil microbial activity are rarely reported. Consequently, cadmium (Cd)- and lead (Pb)-resistant fungi and citric acid (CA) were introduced to enhance phytoextraction by Solanum nigrum L. under varied Cd and Pb pollution levels in a greenhouse pot experiment. We then determined accumulation of Cd and Pb in S. nigrum and the soil enzyme activities of dehydrogenase, phosphatase, urease, catalase, sucrase, and amylase. Detrended canonical correspondence analysis (DCCA) was applied to assess the interactions between remediation strategies and soil enzyme activities. Results indicated that the addition of fungi, CA, or their combination enhanced the root biomass of S. nigrum, especially at the high-pollution level. The combined treatment of CA and fungi enhanced accumulation of Cd about 22-47 % and of Pb about 13-105 % in S. nigrum compared with the phytoextraction alone. However, S. nigrum was not shown to be a hyperaccumulator for Pb. Most enzyme activities were enhanced after remediation. The DCCA ordination graph showed increasing enzyme activity improvement by remediation in the order of phosphatase, amylase, catalase, dehydrogenase, and urease. Responses of soil enzyme activities were similar for both the addition of fungi and that of CA. In summary, results suggest that fungi and CA-assisted phytoextraction is a promising approach to restoring heavy metal polluted soil.

  8. Treatment of recalcitrant wastewater from ethanol and citric acid production using the microalga Chlorella vulgaris and the macrophyte Lemna minuscula.

    PubMed

    Valderrama, Luz T; Del Campo, Claudia M; Rodriguez, Claudia M; de- Bashan, Luz E; Bashan, Yoav

    2002-10-01

    Laboratory-scale experiments were performed to develop a procedure for biological treatment of recalcitrant anaerobic industrial effluent (from ethanol and citric acid production) using first the microalga Chlorella vulgaris followed by the macrophyte Lemna minuscula. This recalcitrant dark-colored wastewater, containing high levels of organic matter and low pH, prevents the growth of microalgae and macrophytes, and therefore, could not be treated by them. Therefore, the wastewater was diluted to 10% of the original concentration with wash water from the production line. Within 4 days of incubation in the wastewater, C. vulgaris population grew from 5 x 10(5) to 2 x 10(6) cells/mL. This culture reduced ammonium ion (71.6%), phosphorus (28%), and chemical oxygen demand (COD) (61%), and dissolved a floating microbial biofilm after 5 days of incubation. Consequently, L. minuscule was able to grow in the treated wastewater (from 7 to 14 g/bioreactor after 6 days), precipitated the microalgal cells (by shading the culture), and reduced other organic matter and color (up to 52%) after an additional 6 days of incubation. However, L. minuscula did not improve removal of nutrients. This study demonstrates the feasibility of combining microalgae and macrophytes for bioremediation of recalcitrant industrial wastewater.

  9. Evaluation of anti-microbial activities of ZnO, citric acid and a mixture of both against Propionibacterium acnes.

    PubMed

    Bae, J Y; Park, S N

    2016-12-01

    In this study, anti-microbial activities of ZnO of three different particle sizes of citric acid (CA) and of mixtures of ZnO and CA were confirmed against Propionibacterium acnes. ZnO with the smallest particle size showed relatively high anti-microbial activity by disc diffusion assay and broth macrodilution assay. The mixtures of ZnO and CA also showed relatively high anti-microbial activity when the particle size of ZnO was the smallest. Furthermore, anti-microbial activities of ZnO, CA and the mixtures of ZnO and CA were compared through the checkerboard assay. The results indicated that a 1 : 1 ratio of ZnO and CA resulted in the highest anti-microbial activity. The substances were confirmed to have synergic anti-microbial effects. With the time-kill curve assay, the mixture of ZnO-containing CA reduced the surviving microbial content the most after 24 h. The results of our study suggest that ZnO may not only be an anti-microbial ingredient for the prevention of and treatment of acne. The results of our study suggest that ZnO may be an anti-microbial ingredient for the prevention of and treatment of acne when mixed with CA. © 2016 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  10. Effect of citric acid on metals mobility in pruning wastes and biosolids compost and metals uptake in Atriplex halimus and Rosmarinus officinalis.

    PubMed

    Tapia, Y; Eymar, E; Gárate, A; Masaguer, A

    2013-05-01

    To assess metal mobility in pruning waste and biosolids compost (pH 6.9 and total concentration of metals in milligram per kilogram of Cd 1.9, Cu 132, Fe 8,513, Mn 192, Pb 81, and Zn 313), shrubs species Atriplex halimus and Rosmarinus officinalis were transplanted in this substrate and irrigated with citric acid (4 g L(-1), pH 2.9) and nutrient solution daily for 60 days. Citric acid significantly increased the concentrations of soluble Mn and Fe in the nutrient substrate solution measured by suction probes, while other metals did not vary in concentration (Cu and Zn) or were not observed at detectable levels (Cd and Pb). In plants, citric acid significantly increased the concentrations of Cu (2.7 ± 0.1-3.3 ± 0.1 mg kg(-1)), Fe (49.2 ± 5.2-76.8 ± 6.8 mg kg(-1)), and Mn (7.2 ± 1.1-11.4 ± 0.7 mg kg(-1)) in leaves of R. officinalis, whereas the concentration of only Mn (25.4 ± 0.3-42.2 ± 2.9 mg kg(-1)) was increased in A. halimus. Increasing Fe and Mn solubility by citric acid addition indicates the possibility of using it to improve plant nutrition. The mobility of metals in this substrate was influenced for the concentration of the metal, the degree of humification of organic matter and its high Fe content.

  11. Spectral management and morphology evolution of β-NaGdF4:Yb3+,Er3+ by tuning the concentration of citric acid

    NASA Astrophysics Data System (ADS)

    Yao, Lu; Xu, Dekang; Lin, Hao; Yang, Shenghong; Zhang, Yueli

    2018-05-01

    β-NaGdF4:Yb3+,Er3+ upconversion (UC) particles were prepared by a facile hydrothermal process with assistance of citric acid (CA). The morphologies of β-NaGdF4 UC particles were controlled by changing the doses of CA in precursor. With an increase CA concentration in precursor, increase sizes of crystals were observed, resulting in the increasing of luminescence intensity. The energy transfer ET mechanism was analyzed in detail.

  12. The effect of citric acid on morphology and photoluminescence properties of white light emitting ZnO-SiO2 nanocomposites

    NASA Astrophysics Data System (ADS)

    Sivakami, R.; Thiyagarajan, P.

    2016-07-01

    The white light emitting ZnO-SiO2 nanocomposites were synthesized by sol-gel combustion method using zinc nitrate, citric acid and tetraethoxysilane. To analyze the effect of fuel content on the photoluminescence properties of ZnO-SiO2 nanocomposites, the citric acid content was varied as 1, 5, and 10 moles with respect to one mole of zinc. The SEM images of the nanocomposites revealed the spherical, flower and platelet like morphology with variation in citric acid content and annealing temperatures. The ZnO-SiO2 nanocomposites prepared with various Zn:CA ratio excited at UV (280 nm), near UV (365 nm), violet (405 nm) and blue (465 nm) wavelength showed blue and greenish-yellow emission. Among all ratios, the ZnO-SiO2 nanocomposites with Zn:CA - 1:1 ratio showed the intense broad band emission compared to Zn:CA - 1:5 and 1:10 values. This particular composition of sample excited under violet (405 nm) LED source shows white light, as confirmed by the CIE chromaticity coordinates (x = 0.342, y = 0.318).

  13. The effect of time in the exposure of theobromine gel to enamel and surface hardness after demineralization with 1% citric acid

    NASA Astrophysics Data System (ADS)

    Irawan, M. I. P.; Noerdin, A.; Eriwati, Y. K.

    2017-08-01

    Theobromine is one of the alkaloid compounds that can be found in cacao (Theobroma cacao). It is said that theobromine can prevent enamel demineralization. The aim of this research was to evaluate the effect of different exposure times to 200 mg/L theobromine gel on enamel microhardness after demineralization in 1% citric acid. Twenty-eight specimens of human premolar teeth were divided into four groups and were immersed in 1% citric acid (pH 4) for 2.5 minutes. Then 200 mg/L theobromine gel was exposed to the specimens for 16 minutes (n = 7), 48 minutes (n = 7), and 96 minutes (n = 7). Enamel microhardness (KHN) values were tested using the Knoop Microhardness Tester (Shimadzu, Japan) using a 50-gram load for 5 seconds. A statistical test was performed using the Friedman test, Wilcoxon test, Kruskal-Wallis test, and Mann-Whitney test. The results showed a significant decrease, of microhardness values after demineralization with 1% citric acid. There was also a significant increase in hardness (p<0.05) after exposure of the demineralized specimens to theobromine gel for 16 minutes (32.3%), 48 minutes (39.8%), and 96 minutes (43.7%). It can be concluded that exposure to 200 mg/L theobromine gel for 16, 48, and 96 minutes increased enamel microhardness.

  14. Structure elucidation and quantification of impurities formed between 6-aminocaproic acid and the excipients citric acid and sorbitol in an oral solution using high-resolution mass spectrometry and nuclear magnetic resonance spectroscopy.

    PubMed

    Schou-Pedersen, Anne Marie V; Cornett, Claus; Nyberg, Nils; Østergaard, Jesper; Hansen, Steen Honoré

    2015-03-25

    Concentrated solutions containing 6-aminocaproic acid and the excipients citric acid and sorbitol have been studied at temperatures of 50°C, 60°C, 70°C and 80°C as well as at 20°C. It has previously been reported that the commonly employed citric acid is a reactive excipient, and it is therefore important to thoroughly investigate a possible reaction between 6-aminocaproic acid and citric acid. The current study revealed the formation of 3-hydroxy-3,4-dicarboxy-butanamide-N-hexanoic acid between 6-aminocaproic acid and citric acid by high-resolution mass spectrometry (HRMS) and nuclear magnetic resonance spectroscopy (NMR). Less than 0.03% of 6-aminocaproic acid was converted to 3-hydroxy-3,4-dicarboxy-butanamide-N-hexanoic acid after 30 days of storage at 80°C. Degradation products of 6-aminocaproic acid were also observed after storage at the applied temperatures, e.g., dimer, trimer and cyclized 6-aminocaproic acid, i.e., caprolactam. No reaction products between D-sorbitol and 6-aminocaproic acid could be observed. 3-Hydroxy-3,4-dicarboxy-butanamide-N-hexanoic acid, dimer and caprolactam were also observed after storage at 20°C for 3 months. The findings imply that an oral solution of 6-aminocaproic acid is relatively stable at 20°C at the pH values 4.00 and 5.00 as suggested in the USP for oral formulations. Compliance with the ICH guideline Q3B is expected. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Influence of barley grain particle size and treatment with citric acid on digestibility, ruminal fermentation and microbial protein synthesis in Holstein calves.

    PubMed

    Kazemi-Bonchenari, M; Salem, A Z M; López, S

    2017-08-01

    Chemical and physical treatments of barley grain increase ruminally resistant starch and can improve the rumen fermentation pattern. The objective of the present study was to evaluate the effects of chemical (addition of citric acid, CA) and physical (grinding to two different particle sizes, PS) treatment of barley grain on performance, rumen fermentation, microbial protein yield in the rumen and selected blood metabolites in growing calves. In all, 28 male Holstein calves (172±5.1 kg initial BW) were used in a complete randomised design with a factorial arrangement of 2 barley grain particle sizes×2 levels of citric acid. The diets were as follows: (i) small PS (average 1200 µm) barley grain soaked in water (no CA addition); (ii) small PS barley grain soaked in a CA solution (adding 20 g CA/kg barley); (iii) large PS (average 2400 µm) barley grain soaked in water (no citric acid addition) and (iv) large PS barley grain soaked in a citric acid solution (adding 20 g CA/kg barley). Barley grain was then incorporated at 35% in a total mixed ration and fed to the calves for 11 weeks. Feeding small PS barley decreased feed intake (P=0.02) and average daily weight gain (P=0.01). The addition of CA to barley grain did not affect intake but increased weight gain (P0.05). However, the molar proportion of propionate was increased (P=0.03) when barley was more finely ground, and that of acetate was increased (P=0.04) when CA was added to barley grain. The ruminal concentration of ammonia nitrogen was increased (P<0.01) and microbial nitrogen synthesis in the rumen tended to decrease by adding CA to barley. Treating barley grain with citric acid increased fibre digestibility of total mixed rations, attenuated the decrease in ruminal pH, and improved weight gain and feed efficiency in male Holstein growing calves fed a high-cereal diet (550 g cereal grain/kg diet).

  16. Evaluation of the Efficacy, Safety, and Tolerability of 3 Dose Regimens of Topical Sodium Nitrite With Citric Acid in Patients With Anogenital Warts: A Randomized Clinical Trial.

    PubMed

    Ormerod, Anthony D; van Voorst Vader, Pieter C; Majewski, Slovomir; Vanscheidt, Wolfgang; Benjamin, Nigel; van der Meijden, Willem

    2015-08-01

    Anogenital warts are a common disorder associated with significant physical and mental distress and a substantial cause of health care costs. To assess the efficacy of the topical application of nitric oxide delivered using acidified nitrite. A multicenter, randomized, controlled, dose-ranging clinical trial was conducted in European genitourinary medicine clinics between December 20, 2001, and January 14, 2003. Analysis was by intent to treat for all individuals initiating therapy. Participants included male and female volunteers older than 18 years with between 2 and 50 external anogenital warts. A total of 299 individuals from 40 centers were randomized to a control arm and a treatment arm that received 3 doses of acidified nitrite applied topically for 12 weeks with an additional 12 weeks of follow-up, with the final follow-up visit on January 14, 2003. Placebo nitrite cream and placebo citric acid cream were applied twice daily. Active treatment was divided as low dose (sodium nitrite, 3%, with citric acid, 4.5%, creams applied twice daily), middle dose (sodium nitrite, 6%, with citric acid, 9%, creams applied once daily at night, with placebo applied in the morning), and high dose (sodium nitrite, 6%, with citric acid, 9%, creams applied twice daily). The primary outcome was proportion of patients with complete clinical clearance of target warts; secondary outcomes were reduction in target wart area and safety. Complete clinical clearance at 12 weeks occurred in 10 of 74 patients (14%; 95% CI, 6%-21%) with placebo; 11 of 72 (15%; 95% CI, 7%-24%) with low-dose treatment; 17 of 74 (23%; 95% CI, 13%-33%) with middle-dose treatment; and 22 of 70 (31%; 95% CI, 21%-42%) with high-dose treatment (P = .01). Reduction in target wart area, time to clearance, and patient and investigator assessments supported the superiority of the high-dose therapy vs placebo. There were no systemic or serious adverse events associated with treatment. However, there was a dose

  17. Correlation between citric acid and nitrate metabolisms during CAM cycle in the atmospheric bromeliad Tillandsia pohliana.

    PubMed

    Freschi, Luciano; Rodrigues, Maria Aurineide; Tiné, Marco Aurélio Silva; Mercier, Helenice

    2010-12-15

    Crassulacean acid metabolism (CAM) confers crucial adaptations for plants living under frequent environmental stresses. A wide metabolic plasticity can be found among CAM species regarding the type of storage carbohydrate, organic acid accumulated at night and decarboxylating system. Consequently, many aspects of the CAM pathway control are still elusive while the impact of this photosynthetic adaptation on nitrogen metabolism has remained largely unexplored. In this study, we investigated a possible link between the CAM cycle and the nitrogen assimilation in the atmospheric bromeliad Tillandsia pohliana by simultaneously characterizing the diel changes in key enzyme activities and metabolite levels of both organic acid and nitrate metabolisms. The results revealed that T. pohliana performed a typical CAM cycle in which phosphoenolpyruvate carboxylase and phosphoenolpyruvate carboxykinase phosphorylation seemed to play a crucial role to avoid futile cycles of carboxylation and decarboxylation. Unlike all other bromeliads previously investigated, almost equimolar concentrations of malate and citrate were accumulated at night. Moreover, a marked nocturnal depletion in the starch reservoirs and an atypical pattern of nitrate reduction restricted to the nighttime were also observed. Since reduction and assimilation of nitrate requires a massive supply of reducing power and energy and considering that T. pohliana lives overexposed to the sunlight, we hypothesize that citrate decarboxylation might be an accessory mechanism to increase internal CO₂ concentration during the day while its biosynthesis could provide NADH and ATP for nocturnal assimilation of nitrate. Therefore, besides delivering photoprotection during the day, citrate might represent a key component connecting both CAM pathway and nitrogen metabolism in T. pohliana; a scenario that certainly deserves further study not only in this species but also in other CAM plants that nocturnally accumulate citrate

  18. Retention Mechanisms of Citric Acid in Ternary Kaolinite-Fe(III)-Citrate Acid Systems Using Fe K-edge EXAFS and L3,2-edge XANES Spectroscopy

    PubMed Central

    Yang, Jianjun; Wang, Jian; Pan, Weinan; Regier, Tom; Hu, Yongfeng; Rumpel, Cornelia; Bolan, Nanthi; Sparks, Donald

    2016-01-01

    Organic carbon (OC) stability in tropical soils is strongly interlinked with multivalent cation interaction and mineral association. Low molecular weight organic acids (LMWOAs) represent the readily biodegradable OC. Therefore, investigating retention mechanisms of LMWOAs in mineral-cation-LMWOAs systems is critical to understanding soil C cycling. Given the general acidic conditions and dominance of kaolinite in tropical soils, we investigated the retention mechanisms of citric acid (CA) in kaolinite-Fe(III)-CA systems with various Fe/CA molar ratios at pH ~3.5 using Fe K-edge EXAFS and L3,2-edge XANES techniques. With Fe/CA molar ratios >2, the formed ferrihydrite mainly contributed to CA retention through adsorption and/or coprecipitation. With Fe/CA molar ratios from 2 to 0.5, ternary complexation of CA to kaolinite via a five-coordinated Fe(III) bridge retained higher CA than ferrihydrite-induced adsorption and/or coprecipitation. With Fe/CA molar ratios ≤0.5, kaolinite-Fe(III)-citrate complexation preferentially occurred, but less CA was retained than via outer-sphere kaolinite-CA complexation. This study highlighted the significant impact of varied Fe/CA molar ratios on CA retention mechanisms in kaolinite-Fe(III)-CA systems under acidic conditions, and clearly showed the important contribution of Fe-bridged ternary complexation on CA retention. These findings will enhance our understanding of the dynamics of CA and other LMWOAs in tropical soils. PMID:27212680

  19. Expression of the H+-ATPase AHA10 proton pump is associated with citric acid accumulation in lemon juice sac cells.

    PubMed

    Aprile, Alessio; Federici, Claire; Close, Timothy J; De Bellis, Luigi; Cattivelli, Luigi; Roose, Mikeal L

    2011-12-01

    The sour taste of lemons (Citrus limon (L.) Burm.) is determined by the amount of citric acid in vacuoles of juice sac cells. Faris is a "sweet" lemon variety since it accumulates low levels of citric acid. The University of California Riverside Citrus Variety Collection includes a Faris tree that produces sweet (Faris non-acid; FNA) and sour fruit (Faris acid; FA) on different branches; it is apparently a graft chimera with layer L1 derived from Millsweet limetta and layer L2 from a standard lemon. The transcription profiles of Faris sweet lemon were compared with Faris acid lemon and Frost Lisbon (L), which is a standard sour lemon genetically indistinguishable from Faris in prior work with SSR markers. Analysis of microarray data revealed that the transcriptomes of the two sour lemon genotypes were nearly identical. In contrast, the transcriptome of Faris sweet lemon was very different from those of both sour lemons. Among about 1,000 FNA-specific, presumably pH-related genes, the homolog of Arabidopsis H(+)-ATPase proton pump AHA10 was not expressed in FNA, but highly expressed in FA and L. Since Arabidopsis AHA10 is involved in biosynthesis and acidification of vacuoles, the lack of expression of the AHA10 citrus homolog represents a very conspicuous molecular feature of the FNA sweet phenotype. In addition, high expression of several 2-oxoglutarate degradation-related genes in FNA suggests activation of the GABA shunt and degradation of valine and tyrosine as components of the mechanism that reduces the level of citric acid in sweet lemon.

  20. Citric acid enhanced the antioxidant defense system and chromium uptake by Lemna minor L. grown in hydroponics under Cr stress.

    PubMed

    Sallah-Ud-Din, Rasham; Farid, Mujahid; Saeed, Rashid; Ali, Shafaqat; Rizwan, Muhammad; Tauqeer, Hafiz Muhammad; Bukhari, Syed Asad Hussain

    2017-07-01

    Phytoextraction is a cost-effective and eco-friendly technique for the removal of pollutants, mainly heavy metal(loids) especially from polluted water and metal-contaminated soils. The phytoextraction of heavy metals is, in general, limited due to the low availability of heavy metals in the growth medium. Organic chelators can help to improve the phytoextraction by increasing metal mobility and solubility in the growth medium. The present research was carried out to examine the possibility of citric acid (CA) in improving chromium (Cr) phytoextraction by Lemna minor (duckweed). For this purpose, healthy plants were collected from nearby marsh and grown in hydroponics under controlled conditions. Initial metal contents of both marsh water and plant were measured along with physico-chemical properties of the marsh water. Different concentrations of Cr and CA were applied in the hydroponics in different combinations after defined intervals. Continuous aeration was supplied and pH maintained at 6.5 ± 0.1. Results showed that increasing concentration of Cr significantly decreased the plant biomass, photosynthetic pigments, leaf area, and antioxidant enzyme activities (like catalase, ascorbate peroxidase, superoxide dismutase, peroxidase). Furthermore, Cr stress increased the Cr concentrations, electrolyte leakage, hydrogen peroxide, and malondialdehyde contents in plants. The addition of CA alleviated the Cr-induced toxicity in plants and further enhanced the Cr uptake and its accumulation in L. minor. The addition of CA enhanced the Cr concentration in L. minor by 6.10, 26.5, 20.5, and 20.2% at 0, 10, 100, and 200 μM Cr treatments, respectively, compared to the respective Cr treatments without CA. Overall, the results of the present study showed that CA addition may enhance the Cr accumulation and tolerance in L. minor by enhancing the plant growth and activities of antioxidant enzymes.

  1. Determination of boron in blood, urine and bone by electrothermal atomic absorption spectrometry using zirconium and citric acid as modifiers

    NASA Astrophysics Data System (ADS)

    Burguera, Marcela; Burguera, José Luis; Rondón, Carlos; Carrero, Pablo

    2001-10-01

    A comparative study of various potential chemical modifiers (Au, Ba, Be, Ca, Cr, Ir, La, Lu, Mg, Ni, Pd, Pt, Rh, Ru, Sr, V, W, and Zr), and different 'coating' treatments (Zr, W, and W+Rh) of the pyrolytic graphite platform of a longitudinally heated graphite tube atomizer for thermal stabilization and determination of boron was undertaken. The use of Au, Ba, Be, Cr, Ir, Pt, Rh, Ru, Sr and V as modifiers, and of W+Rh coating produced erratic, and noisy signals, while the addition of La, Ni and Pd as modifiers, and the W coating had positive effects, but with too high background absorption signals, rendering their use unsuitable for boron determination even in aqueous solutions. The atomic absorption signal for boron was increased and stabilized when the platform was coated with Zr, and by the addition of Ca, Mg, Lu, W or Zr as modifiers. Only the addition of 10 μg of Zr as a modifier onto Zr-treated platforms allowed the use of a higher pyrolysis temperature without analyte losses. The memory effect was minimized by incorporating a cleaning step with 10 μl of 50 g l -1 NH 4F HF after every three boron measurements. The addition of 10 μl of 15 g l -1 citric acid together with Zr onto Zr-treated platforms significantly improved the characteristic mass to m0=282 pg, which is adequate for biological samples such as urine and bone, although the sensitivity was still inadequate for the determination of boron in blood of subjects without supplementary diet. Under optimized conditions, the detection limit (3σ) was 60 μg l -1. The amount of boron found in whole blood, urine and femur head samples from patients with osteoporosis was in agreement with values previously reported in the literature.

  2. Comparison of EDTA- and citric acid-enhanced phytoextraction of heavy metals in artificially metal contaminated soil by Typha angustifolia.

    PubMed

    Muhammad, Dawood; Chen, Fei; Zhao, Jing; Zhang, Guoping; Wu, Feibo

    2009-08-01

    A pot experiment was conducted to study the performance of EDTA and citric acid (CA) addition in improving phytoextraction of Cd, Cu, Pb, and Cr from artificially contaminated soil by T. angustifolia. T. angustifolia showed the remarkable resistance to heavy metal toxicity with no visual toxic symptom including chlorosis and necrosis when exposed to metal stress. EDTA-addition significantly reduced plant height and biomass, compared with the control, and stunted plant growth, while 2.5 and 5 mM CA addition induced significant increases in root dry weight. EDTA, and 5 and 10 mM CA significantly increased shoot Cd, Pb, and Cr concentrations compared with the control, with EDTA being more effective. At final harvest, the highest shoot Cd, Cr, and Pb concentrations were recorded in the treatment of 5 mM EDTA addition, while maximal root Pb concentration was found at the 2.5 mM CA treatment. However, shoot Cd accumulation in the 10 mM CA treatment was 36.9% higher than that in 2.5 mM EDTA, and similar with that in 10 mM EDTA. Shoot Pb accumulation was lower in 10 mM CA than that in EDTA treatments. Further, root Cd, Cu, and Pb accumulation of CA treatments and shoot Cr accumulation in 5 or 10 mM CA treatments were markedly higher than that of control and EDTA treatments. The results also showed that EDTA dramatically increased the dissolution of Cu, Cr, Pb, and Cd in soil, while CA addition had less effect on water-soluble Cu, Cr, and Cd, and no effect on Pb levels. It is suggested that CA can be a good chelator candidate for T. angustifolia used for environmentally safe phytoextraction of Cd and Cr in soils.

  3. Screening of agro-industrial wastes for citric acid bioproduction by Aspergillus niger NRRL 2001 through solid state fermentation.

    PubMed

    Dhillon, Gurpreet S; Brar, Satinder K; Kaur, Surinder; Verma, Mausam

    2013-05-01

    The citric acid (CA) industry is currently struggling to develop a sustainable and economical process owing to high substrate and energy costs. Increasing interest in the replacement of costly synthetic substrates by renewable waste biomass has fostered research on agro-industrial wastes and screening of raw materials for economical CA production. The food-processing industry generates substantial quantities of waste biomass that could be used as a valuable low-cost fermentation substrate. The present study evaluated the potential of different agro-industrial wastes, namely apple pomace (AP), brewer's spent grain, citrus waste and sphagnum peat moss, as substrates for solid state CA production using Aspergillus niger NRRL 2001. Among the four substrates, AP resulted in highest CA production of 61.06 ± 1.9 g kg(-1) dry substrate (DS) after a 72 h incubation period. Based on the screening studies, AP was selected for optimisation studies through response surface methodology (RSM). Maximum CA production of 312.32 g kg(-1) DS was achieved at 75% (v/w) moisture and 3% (v/w) methanol after a 144 h incubation period. The validation of RSM-optimised parameters in plastic trays resulted in maximum CA production of 364.4 ± 4.50 g kg(-1) DS after a 120 h incubation period. The study demonstrated the potential of AP as a cheap substrate for higher CA production. This study contributes to knowledge about the future application of carbon rich agro-industrial wastes for their value addition to CA. It also offers economic and environmental benefits over traditional ways used to dispose off agro-industrial wastes. © 2012 Society of Chemical Industry.

  4. Hygroscopicity of internally mixed particles composed of (NH4)2SO4 and citric acid under pulsed RH change.

    PubMed

    Shi, Xiao-Min; Wu, Feng-Min; Jing, Bo; Wang, Na; Xu, Lin-Lin; Pang, Shu-Feng; Zhang, Yun-Hong

    2017-12-01

    In this research, we applied a pulsed RH controlling system and a rapid scan vacuum FTIR spectrometer (PRHCS-RSVFTIR) to investigate hygroscopicity of internally mixed (NH 4 ) 2 SO 4 (AS)/citric acid (CA) particles. The water content and efflorescence ratio of AS in the particles and ambient relative humidity (RH) as a function of time were obtained with a subsecond time resolution. The hygroscopic behavior of AS aerosols in two different RH control processes (equilibrium and RH pulsed processes) showed that AS droplets crystallize with RH ranging from 42% to 26.5%. It was found that the half-life time ratio between the water content in the CA particles and the gas phase under RH pulsed change was greater than one under low RH conditions (<40% RH), indicating the significant water transfer limitation due to the high viscosity of CA aerosols at low RH, especially at RH<20%. In addition, water diffusion constants between 10 -12  m 2  s -1 and 10 -13  m 2  s -1 in micron size CA aerosols were obtained in a sub-second and second timescale. The addition of AS enhanced the water transfer limitation in the mixed aerosols. The efflorescence relative humidity (ERH) of the mixed particles with AS/CA by molar ratio 3:1 was found between 22.7% and 5.9%, which was much lower than AS particles. No efflorescence process was observed for the 1:1 mixed particles, indicating that CA greatly suppressed nucleation of AS. Our results have shown that the PRHCS-RSVFTIR is effective to simulate hygroscopicity and water transport of aerosols under fast variations in RH in atmosphere. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Phytoextraction of contaminated urban soils by Panicum virgatum L. enhanced with application of a plant growth regulator (BAP) and citric acid.

    PubMed

    Aderholt, Matthew; Vogelien, Dale L; Koether, Marina; Greipsson, Sigurdur

    2017-05-01

    Lead (Pb) contamination in soil represents a threat to human health. Phytoextraction has gained attention as a potential alternative to traditional remediation methods because of lower cost and minimal soil disruption. The North American native switchgrass (Panicum virgatum L.) was targeted due to its ability to produce high biomass and grow across a variety of ecozones. In this study switchgrass was chemically enhanced with applications of the soil-fungicide benomyl, chelates (EDTA and citric acid), and PGR to optimize phytoextraction of Pb and zinc (Zn) from contaminated urban soils in Atlanta, GA. Exogenous application of two plant hormones was compared in multiple concentrations to determine effects on switchgrass growth: indole-3-acetic acid (IAA), and Gibberellic Acid (GA 3 ), and one PGR benzylaminopurine (BAP), The PGR BAP (1.0 μM) was found to generate a 48% increase in biomass compared to Control plants. Chemical application of citric acid, EDTA, benomyl, and BAP were tested separately and in combination in a pot experiment in an environmentally controlled greenhouse to determine the efficacy of phtyoextraction by switchgrass. Soil acidification by citric acid application resulted in highest level of aluminum (Al) and iron (Fe) in plants foliage resulting in severe phytotoxic effects. Total Pb phytoextraction was significantly highest in plants treated with combined chemical application of B + C and B + C + H. Suppression of AMF activities by benomyl application significantly increased concentrations of Al and Fe in roots. Application of benomyl reduced AMF colonization but was also shown to dramatically increase levels of septa fungi infection as compared to Control plants. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. The effect of pH on citric acid cough challenge: A randomised control trial in chronic cough and healthy volunteers.

    PubMed

    Rai, Z L; Fowles, H E; Wright, C; Howard, Joseph; Morice, A H

    2018-03-06

    Citric acid has been used for over six decades to induce cough; however the mechanism of its pro-tussive effect is still not fully understood. We assessed the response to inhalation of citric acid at varying levels of acidity to determine if the pH of the solution plays a role in the induction of cough. Data was collected from both healthy volunteers and patients with chronic cough. 20 chronic cough patients and 20 healthy volunteers were recruited and underwent three cough challenges on separate days. Each visit involved 5 repeated one second inhalations of 300 mM citric acid solution. The concentration of the citrate cation remained constant, but the pH of the solution altered by the addition of sodium bicarbonate to 3, 5 and 6, representing the pK a values of the individual acid moieties. The total number of coughs elicited was recorded for each inhalation. Two subjects withdrew and were not included in the analysis. Participants were gender matched, each group consisting of 12 females. 74% of chronic coughers coughed at pH 3 (mean coughs 16), 89% coughed at pH 5 (18) and 63% coughed at pH 6 (7). In healthy volunteers, 60% of subjects coughed at pH 3 (9), 30% of subjects coughed at pH 5 (3), and 10% of subjects coughed at pH 6 (0). Thus chronic cough patients coughed more than healthy volunteers and did not exhibit a clear pH concentration response. There was also a greater variability in their response to individual challenges. Copyright © 2018 Elsevier B.V. All rights reserved.

  7. Aerosol Fragmentation Driven by Coupling of Acid–Base and Free-Radical Chemistry in the Heterogeneous Oxidation of Aqueous Citric Acid by OH Radicals

    DOE PAGES

    Liu, Matthew J.; Wiegel, Aaron A.; Wilson, Kevin R.; ...

    2017-07-14

    A key uncertainty in the heterogeneous oxidation of carboxylic acids by hydroxyl radicals (OH) in aqueous-phase aerosol is how the free-radical reaction pathways might be altered by acid-base chemistry. In particular, if acid-base reactions occur concurrently with acyloxy radical formation and unimolecular decomposition of alkoxy radicals, there is a possibility that differences in reaction pathways impact the partitioning of organic carbon between the gas and aqueous phases. To examine these questions, a kinetic model is developed for the OH-initiated oxidation of citric acid aerosol at high relative humidity. The reaction scheme, containing both free-radical and acid-base elementary reaction steps withmore » physically validated rate coefficients, accurately predicts the experimentally observed molecular composition, particle size, and average elemental composition of the aerosol upon oxidation. The difference between the two reaction channels centers on the reactivity of carboxylic acid groups. Free-radical reactions mainly add functional groups to the carbon skeleton of neutral citric acid, because carboxylic acid moieties deactivate the unimolecular fragmentation of alkoxy radicals. In contrast, the conjugate carboxylate groups originating from acid-base equilibria activate both acyloxy radical formation and carbon-carbon bond scission of alkoxy radicals, leading to the formation of low molecular weight, highly oxidized products such as oxalic and mesoxalic acid. Subsequent hydration of carbonyl groups in the oxidized products increases the aerosol hygroscopicity and accelerates the substantial water uptake and volume growth that accompany oxidation. These results frame the oxidative lifecycle of atmospheric aerosol: it is governed by feedbacks between reactions that first increase the particle oxidation state, then eventually promote water uptake and acid-base chemistry. When coupled to free-radical reactions, acid-base channels lead to formation of low

  8. Aerosol Fragmentation Driven by Coupling of Acid–Base and Free-Radical Chemistry in the Heterogeneous Oxidation of Aqueous Citric Acid by OH Radicals

    SciTech Connect

    Liu, Matthew J.; Wiegel, Aaron A.; Wilson, Kevin R.

    A key uncertainty in the heterogeneous oxidation of carboxylic acids by hydroxyl radicals (OH) in aqueous-phase aerosol is how the free-radical reaction pathways might be altered by acid-base chemistry. In particular, if acid-base reactions occur concurrently with acyloxy radical formation and unimolecular decomposition of alkoxy radicals, there is a possibility that differences in reaction pathways impact the partitioning of organic carbon between the gas and aqueous phases. To examine these questions, a kinetic model is developed for the OH-initiated oxidation of citric acid aerosol at high relative humidity. The reaction scheme, containing both free-radical and acid-base elementary reaction steps withmore » physically validated rate coefficients, accurately predicts the experimentally observed molecular composition, particle size, and average elemental composition of the aerosol upon oxidation. The difference between the two reaction channels centers on the reactivity of carboxylic acid groups. Free-radical reactions mainly add functional groups to the carbon skeleton of neutral citric acid, because carboxylic acid moieties deactivate the unimolecular fragmentation of alkoxy radicals. In contrast, the conjugate carboxylate groups originating from acid-base equilibria activate both acyloxy radical formation and carbon-carbon bond scission of alkoxy radicals, leading to the formation of low molecular weight, highly oxidized products such as oxalic and mesoxalic acid. Subsequent hydration of carbonyl groups in the oxidized products increases the aerosol hygroscopicity and accelerates the substantial water uptake and volume growth that accompany oxidation. These results frame the oxidative lifecycle of atmospheric aerosol: it is governed by feedbacks between reactions that first increase the particle oxidation state, then eventually promote water uptake and acid-base chemistry. When coupled to free-radical reactions, acid-base channels lead to formation of low

  9. Effect of strategic administration of an encapsulated blend of formic acid, citric acid, and essential oils on Salmonella carriage, seroprevalence, and growth of finishing pigs.

    PubMed

    Walia, Kavita; Argüello, Hector; Lynch, Helen; Leonard, Finola C; Grant, Jim; Yearsley, Dermot; Kelly, Sinead; Duffy, Geraldine; Gardiner, Gillian E; Lawlor, Peadar G

    2017-02-01

    Controlling Salmonella at farm level can act as the first line of defence in reducing salmonellosis from pork. This study investigated the efficacy of an encapsulated blend of formic acid, citric acid, and essential oils (FormaXOL™) administered to finisher pigs for 28days prior to slaughter in controlling Salmonella shedding on a commercial farm with a history of high Salmonella seroprevalence. Fourteen pens of 8-10 pigs/pen were randomly assigned to a control (finisher diet without additive) or a treatment group (the same diet with 4kg/t of FormaXOL™) for 28 days. Faeces were collected from each pig on days 0, 14, and 28, while on day 29 blood, caecal digesta and ileocaecal-mesenteric lymph nodes were collected at slaughter. Pigs were weighed at the start and end of the trial, feed intake was recorded, and carcass quality parameters were recorded at slaughter. On day 14, Salmonella shedding was reduced in the treatment compared to the control group (27.9% versus 51.7% probability of detecting Salmonella in faeces, respectively; p=0.001). However, on day 28, no reduction was observed (20.6% versus 35.9% probability of detecting Salmonella in faeces, respectively; p=0.07). Interestingly, Salmonella shedding rates in the treated pigs remained stable throughout the trial compared to the control group. This suggests that the feed additive prevented additional pigs from acquiring the Salmonella infection. A lower Salmonella seroprevalence was detected at slaughter in the treatment compared to the control group using the 40% optical density cut-off (64.5% versus 88.5%, respectively; p=0.01). However, no significant differences in Salmonella recovery rates were observed in the caecal digesta or lymph nodes between treated and control groups. Treated pigs had a lower feed intake than pigs fed the control diet (p=0.001); however, average daily gain and feed conversion efficiency were not affected by treatment (p=0.45 and 0.55, respectively). Consequently, supplementing

  10. Beta-oxidation as channeled reaction linked to citric acid cycle: evidence from measurements of mitochondrial pyruvate oxidation during fatty acid degradation.

    PubMed

    Förster, M E; Staib, W

    1992-07-01

    1. The kinetics of mitochondrial mammalian pyruvate dehydrogenase multienzyme complex (PDHC) is studied by the formation of CO2 using tracer amounts of [1-14C]pyruvate. It is found that the Hill plot results in a (pseudo-)cooperativity with a transition of n-1----3 at a pyruvate concentration about Ks. 2. Addition of L-carnitine, octanoate, palmitoyl-CoA or palmitate + L-carnitine + fatty acid-binding protein results in a Hill coefficient of n = 2 following the kinetics of pyruvate oxidation. 3. Addition of fatty acid-binding protein to an assay system oxidizing palmitate in presence of L-carnitine alters the pattern of the kinetics in the Hill plot so that an apparently lower level of L-carnitine is necessary for the reaction course of beta-degradation. 4. It is concluded that beta-degradation is a coordinated, multienzyme-complex based mechanism tightly linked to citric acid cycle and it is proposed that L-carnitine is actively involved into the reaction and not only functioning as carrier-molecule for transmembrane transport.

  11. Effect of stevia and citric acid on the stability of phenolic compounds and in vitro antioxidant and antidiabetic capacity of a roselle (Hibiscus sabdariffa L.) beverage.

    PubMed

    Pérez-Ramírez, Iza F; Castaño-Tostado, Eduardo; Ramírez-de León, José A; Rocha-Guzmán, Nuria E; Reynoso-Camacho, Rosalía

    2015-04-01

    Plant infusions are consumed due to their beneficial effects on health, which is attributed to their bioactive compounds content. However, these compounds are susceptible to degradation during processing and storage. The objective of this research was to evaluate the effect of stevia and citric acid on the stability of phenolic compounds, antioxidant capacity and carbohydrate-hydrolysing enzyme inhibitory activity of roselle beverages during storage. The optimum extraction conditions of roselle polyphenolic compounds was of 95 °C/60 min, which was obtained by a second order experimental design. The incorporation of stevia increased the stability of colour and some polyphenols, such as quercetin, gallic acid and rosmarinic acid, during storage. In addition, stevia decreased the loss of ABTS, DPPH scavenging activity and α-amylase inhibitory capacity, whereas the incorporation of citric acid showed no effect. These results may contribute to the improvement of technological processes for the elaboration of hypocaloric and functional beverages. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Effect of citric acid and rhizosphere bacteria on metal plaque formation and metal accumulation in reeds in synthetic acid mine drainage solution.

    PubMed

    Guo, Lin; Cutright, Teresa J

    2014-06-01

    Many of regions in the world have been affected by acid mine drainage (AMD). The study assessed the effect of rhizosphere bacteria and citric acid (CA) on the metal plaque formation and heavy metal uptake in Phragmites australis cultured in synthetic AMD solution. Mn and Al plaque were not formed, but Fe plaque which was mediated by rhizosphere iron oxidizing bacteria (Fe(II)OB) was observed on the root system of reeds. Fe plaque did not significantly influence the uptake of Fe, Al and Mn into tissues of reeds. CA significantly (p<0.01) inhibited the growth of Fe(II)OB and decreased the formation of Fe plaque. CA also significantly improved (p<0.05) the accumulation of Fe, Mn and Al in all the tissues of reeds. Roots and rhizomes were the main organs to store metals. The roots contained 0.08±0.01mg/g Mn, 2.39±0.26mg/g Fe and 0.19±0.02mg/g Al, while the shoots accumulated 0.04±0.00mg/g Mn, 0.20±0.01mg/g Fe, 0.11±0.00mg/g Al in reeds cultured in solution amended with 2.101g/l CA and without inoculation of rhizosphere bacteria. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. Study of variation in thermal width of nematic and induced smectic ordering phase of citric acid (CA) and 4-heptyloxybenzoic acid (7OBA) hydrogen bonded liquid crystal complexes

    NASA Astrophysics Data System (ADS)

    Sundaram, S.; Jayaprakasam, R.; Praveena, R.; Rajasekaran, T. R.; Senthil, T. S.; Vijayakumar, V. N.

    2018-01-01

    Hydrogen-bonded liquid crystals (HBLCs) have been derived from nonmesogenic citric acid (CA) and mesogenic 4-heptyloxybenzoic acid (7OBA) yielding a highly ordered smectic C (Sm C) phase along with the new smectic X (Sm X) phase which has been identified as fingerprint-type texture. Optical (polarizing optical microscopy), thermal (differential scanning calorimetry) and structural (Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy) properties are studied. A noteworthy observation is that the intermolecular H-bond (between CA and 7OBA) influences on its melting point and clearing temperature of the HBLCs which exhibits lower value than those of the individual compounds. A typical extended mesophase region has been observed in the present complex while varying the mixture ratio (1:1 to 1:3) than those of individual compounds. The change in the ratio of the mesogenic compound in the mixture alters thermal properties such as enthalpy value and thermal span width in nematic (N) region of HBLC complex. Optical tilt angle measurement of CA+7OBA in Sm C phase has been discussed to identify the molecular position in the mesophase.

  14. Aging deteriorated perception of urge-to-cough without changing cough reflex threshold to citric acid in female never-smokers.

    PubMed

    Ebihara, Satoru; Ebihara, Takae; Kanezaki, Masashi; Gui, Peijun; Yamasaki, Miyako; Arai, Hiroyuki; Kohzuki, Masahiro

    2011-06-28

    The effect of aging on the cognitive aspect of cough has not been studied yet. The purpose of this study is to investigate the aging effect on the perception of urge-to-cough in healthy individuals. Fourteen young, female, healthy never-smokers were recruited via public postings. Twelve elderly female healthy never-smokers were recruited from a nursing home residence. The cough reflex threshold and the urge-to-cough were evaluated by inhalation of citric acid. The cough reflex sensitivities were defined as the lowest concentration of citric acid that elicited two or more coughs (C2) and five or more coughs (C5). The urge-to-cough was evaluated using a modified the Borg scale. There was no significant difference in the cough reflex threshold to citric acid between young and elderly subjects. The urge-to-cough scores at the concentration of C2 and C5 were significantly smaller in the elderly than young subjects. The urge-to-cough log-log slope in elderly subjects (0.73 ± 0.71 point · L/g) was significantly gentler than those of young subjects (1.35 ± 0.53 point · L/g, p < 0.01). There were no significant differences in the urge-to-cough threshold estimated between young and elderly subjects. The cough reflex threshold did not differ between young and elderly subjects whereas cognition of urge-to-cough was significantly decreased in elderly subjects in female never-smokers. Objective monitoring of cough might be important in the elderly people.

  15. Citric acid- and Tween(®) 80-assisted phytoremediation of a co-contaminated soil: alfalfa (Medicago sativa L.) performance and remediation potential.

    PubMed

    Agnello, A C; Huguenot, D; van Hullebusch, E D; Esposito, G

    2016-05-01

    A pot experiment was designed to assess the phytoremediation potential of alfalfa (Medicago sativa L.) in a co-contaminated (i.e., heavy metals and petroleum hydrocarbons) soil and the influence of citric acid and Tween(®) 80 (polyethylene glycol sorbitan monooleate), applied individually and combined together, for their possible use in chemically assisted phytoremediation. The results showed that alfalfa plants could tolerate and grow in a co-contaminated soil. Over a 90-day experimental time, shoot and root biomass increased and negligible plant mortality occurred. Heavy metals were uptaken by alfalfa to a limited extent, mostly by plant roots, and their concentration in plant tissues were in the following order: Zn > Cu > Pb. Microbial population (alkane-degrading microorganisms) and activity (lipase enzyme) were enhanced in the presence of alfalfa with rhizosphere effects of 9.1 and 1.5, respectively, after 90 days. Soil amendments did not significantly enhance plant metal concentration or total uptake. In contrast, the combination of citric acid and Tween(®) 80 significantly improved alkane-degrading microorganisms (2.4-fold increase) and lipase activity (5.3-fold increase) in the rhizosphere of amended plants, after 30 days of experiment. This evidence supports a favorable response of alfalfa in terms of tolerance to a co-contaminated soil and improvement of rhizosphere microbial number and activity, additionally enhanced by the joint application of citric acid and Tween(®) 80, which could be promising for future phytoremediation applications.

  16. Synthesis of high intrinsic loss power aqueous ferrofluids of iron oxide nanoparticles by citric acid-assisted hydrothermal-reduction route

    SciTech Connect

    Behdadfar, Behshid, E-mail: bbehdadfar@ma.iut.ac.ir; Kermanpur, Ahmad; Sadeghi-Aliabadi, Hojjat

    Monodispersed aqueous ferrofluids of iron oxide nanoparticle were synthesized by hydrothermal-reduction route. They were characterized by X-ray diffraction analysis, Fourier transform infrared spectroscopy, scanning and transmission electron microscopy and dynamic light scattering. The results showed that certain concentrations of citric acid (CA) are required to obtain only magnetic iron oxides with mean particle sizes around 8 nm. CA acts as a modulator and reducing agent in iron oxide formation which controls nanoparticle size. The XRD, magnetic and heating measurements showed that the temperature and time of hydrothermal reaction can affect the magnetic properties of obtained ferrofluids. The synthesized ferrofluids weremore » stable at pH 7. Their mean hydrodynamic size was around 80 nm with polydispersity index (PDI) of 0.158. The calculated intrinsic loss power (ILP) was 9.4 nHm{sup 2}/kg. So this clean and cheap route is an efficient way to synthesize high ILP aqueous ferrofluids applicable in magnetic hyperthermia. - Graphical abstract: Monodispersed aqueous ferrofluids of iron oxide nanoparticles were synthesized by hydrothermal-reduction method with citric acid as reductant which is an efficient way to synthesize aqueous ferrofluids applicable in magnetic hyperthermia. Highlights: Black-Right-Pointing-Pointer Aqueous iron oxide ferrofluids were synthesized by hydrothermal-reduction route. Black-Right-Pointing-Pointer Citric acid acted as reducing agent and surfactant in the route. Black-Right-Pointing-Pointer This is a facile, low energy and environmental friendly route. Black-Right-Pointing-Pointer The aqueous iron oxide ferrofluids were monodispersed and stable at pH of 7. Black-Right-Pointing-Pointer The calculated intrinsic loss power of the synthesized ferrofluids was very high.« less

  17. Use of enhanced nisin derivatives in combination with food-grade oils or citric acid to control Cronobacter sakazakii and Escherichia coli O157:H7.

    PubMed

    Campion, Alicia; Morrissey, Ruth; Field, Des; Cotter, Paul D; Hill, Colin; Ross, R Paul

    2017-08-01

    Cronobacter sakazakii and Escherichia coli O157:H7 are well known food-borne pathogens that can cause severe disease. The identification of new alternatives to heating to control these pathogens in foods, while reducing the impact on organoleptic properties and nutritional value, is highly desirable. In this study, nisin and its bioengineered variants, nisin V and nisin S29A, are used alone, or in combination with plant essential oils (thymol, carvacrol and trans-cinnamaldehyde) or citric acid, with a view to controlling C. sakazakii and E. coli O157:H7 in laboratory-based assays and model food systems. The use of nisin variants (30 μM) with low concentrations of thymol (0.015%), carvacrol (0.03%) and trans-cinnamaldehyde (0.035%) resulted in extended lag phases of growth compared to those for corresponding nisin A-essential oil combinations. Furthermore, nisin variants (60 μM) used in combination with carvacrol (0.03%) significantly reduced viable counts of E. coli O157:H7 (3-log) and C. sakazakii (4-log) compared to nisin A-carvacrol treatment. Importantly, this increased effectiveness translated into food. More specifically, sub-inhibitory concentrations of nisin variants and carvacrol caused complete inactivation of E. coli O157:H7 in apple juice within 3 h at room temperature compared to that of the equivalent nisin A combination. Furthermore, combinations of commercial Nisaplin and the food additive citric acid reduced C. sakazakii numbers markedly in infant formula within the same 3 h period. These results highlight the potential benefits of combining nisin and variants thereof with carvacrol and/or citric acid for the inhibition of Gram negative food-borne pathogens. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Cotton textiles modified with citric acid as efficient anti-bacterial agent for prevention of nosocomial infections

    PubMed Central

    Bischof Vukušić, Sandra; Flinčec Grgac, Sandra; Budimir, Ana; Kalenić, Smilja

    2011-01-01

    Aim To study the antimicrobial activity of citric acid (CA) and sodium hypophosphite monohydrate (SHP) against gram-positive and gram-negative bacteria, and to determine the influence of conventional and microwave thermal treatments on the effectiveness of antimicrobial treatment of cotton textiles. Method Textile material was impregnated with CA and SHP solution and thermally treated by either conventional or microwave drying/curing treatment. Antibacterial effectiveness was tested according to the ISO 20743:2009 standard, using absorption method. The surfaces were morphologically observed by scanning electron microscopy, while physical characteristics were determined by wrinkle recovery angles method (DIN 53 891), tensile strength (DIN 53 837), and whiteness degree method (AATCC 110-2000). Results Cotton fabric treated with CA and SHP showed significant antibacterial activity against MRSA (6.38 log10 treated by conventional drying and 6.46 log10 treated by microwave drying before washing, and 6.90 log10 and 7.86 log10, respectively, after 1 cycle of home domestic laundering washing [HDLW]). Antibacterial activity was also remarkable against S. aureus (4.25 log10 by conventional drying, 4.58 log10 by microwave drying) and against P. aeruginosa (1.93 log10 by conventional and 4.66 log10 by microwave drying). Antibacterial activity against P. aeruginosa was higher in samples subjected to microwave drying/curing than in those subjected to conventional drying/curing. As expected, antibacterial activity was reduced after 10 HDLW cycles but the compound was still effective. The surface of the untreated cotton polymer was smooth, while minor erosion stripes appeared on the surfaces treated with antimicrobial agent, and long and deep stripes were found on the surface of the washed sample. Conclusion CA can be used both for the disposable (non-durable) materials (gowns, masks, and cuffs for blood pressure measurement) and the materials that require durability to laundering

  19. Facile fabrication of luminescent organic dots by thermolysis of citric acid in urea melt, and their use for cell staining and polyelectrolyte microcapsule labelling.

    PubMed

    Zholobak, Nadezhda M; Popov, Anton L; Shcherbakov, Alexander B; Popova, Nelly R; Guzyk, Mykhailo M; Antonovich, Valeriy P; Yegorova, Alla V; Scrypynets, Yuliya V; Leonenko, Inna I; Baranchikov, Alexander Ye; Ivanov, Vladimir K

    2016-01-01

    Luminescent organic dots (O-dots) were synthesized via a one-pot, solvent-free thermolysis of citric acid in urea melt. The influence of the ratio of the precursors and the duration of the process on the properties of the O-dots was established and a mechanism of their formation was hypothesized. The multicolour luminescence tunability and toxicity of synthesized O-dots were extensively studied. The possible applications of O-dots for alive/fixed cell staining and labelling of layer-by-layer polyelectrolyte microcapsules were evaluated.

  20. Ultrafine nanoporous palladium-aluminum film fabricated by citric acid-assisted hot-water-treatment of aluminum-palladium alloy film

    SciTech Connect

    Harumoto, Takashi; Tamura, Yohei; Ishiguro, Takashi, E-mail: ishiguro@rs.noda.tus.ac.jp

    Hot-water-treatment has been adapted to fabricate ultrafine nanoporous palladium-aluminum film from aluminum-palladium alloy film. Using citric acid as a chelating agent, a precipitation of boehmite (aluminum oxide hydroxide, AlOOH) on the nanoporous palladium-aluminum film was suppressed. According to cross-sectional scanning transmission electron microscopy observations, the ligament/pore sizes of the prepared nanoporous film were considerably small (on the order of 10 nm). Since this fabrication method only requires aluminum alloy film and hot-water with chelating agent, the ultrafine nanoporous film can be prepared simply and environmentally friendly.

  1. Facile fabrication of luminescent organic dots by thermolysis of citric acid in urea melt, and their use for cell staining and polyelectrolyte microcapsule labelling

    PubMed Central

    Zholobak, Nadezhda M; Popov, Anton L; Shcherbakov, Alexander B; Popova, Nelly R; Guzyk, Mykhailo M; Antonovich, Valeriy P; Yegorova, Alla V; Scrypynets, Yuliya V; Leonenko, Inna I; Baranchikov, Alexander Ye

    2016-01-01

    Luminescent organic dots (O-dots) were synthesized via a one-pot, solvent-free thermolysis of citric acid in urea melt. The influence of the ratio of the precursors and the duration of the process on the properties of the O-dots was established and a mechanism of their formation was hypothesized. The multicolour luminescence tunability and toxicity of synthesized O-dots were extensively studied. The possible applications of O-dots for alive/fixed cell staining and labelling of layer-by-layer polyelectrolyte microcapsules were evaluated. PMID:28144539

  2. Retention mechanisms of citric acid in ternary kaolinite-Fe(III)-citrate acid systems using Fe K-edge EXAFS and L 3,2-edge XANES spectroscopy

    DOE PAGES

    Yang, Jianjun; Wang, Jian; Pan, Weinan; ...

    2016-05-23

    Organic carbon (OC) stability in tropical soils is strongly interlinked with multivalent cation interaction and mineral association. Low molecular weight organic acids (LMWOAs) represent the readily biodegradable OC. Therefore, investigating retention mechanisms of LMWOAs in mineral-cation-LMWOAs systems is critical to understanding soil C cycling. Given the general acidic conditions and dominance of kaolinite in tropical soils, we investigated the retention mechanisms of citric acid (CA) in kaolinite-Fe(III)-CA systems with various Fe/CA molar ratios at pH ~3.5 using Fe K-edge EXAFS and L- 3,2-edge XANES techniques. With Fe/CA molar ratios >2, the formed ferrihydrite mainly contributed to CA retention through adsorptionmore » and/or coprecipitation. With Fe/CA molar ratios from 2 to 0.5, ternary complexation of CA to kaolinite via a five-coordinated Fe(III) bridge retained higher CA than ferrihydrite-induced adsorption and/or coprecipitation. With Fe/CA molar ratios ≤ 0.5, kaolinite-Fe(III)-citrate complexation preferentially occurred, but less CA was retained than via outer-sphere kaolinite-CA complexation. This study highlighted the significant impact of varied Fe/CA molar ratios on CA retention mechanisms in kaolinite-Fe(III)-CA systems under acidic conditions, and clearly showed the important contribution of Fe-bridged ternary complexation on CA retention. In conclusion, these findings will enhance our understanding of the dynamics of CA and other LMWOAs in tropical soils.« less

  3. Retention mechanisms of citric acid in ternary kaolinite-Fe(III)-citrate acid systems using Fe K-edge EXAFS and L 3,2-edge XANES spectroscopy

    SciTech Connect

    Yang, Jianjun; Wang, Jian; Pan, Weinan

    Organic carbon (OC) stability in tropical soils is strongly interlinked with multivalent cation interaction and mineral association. Low molecular weight organic acids (LMWOAs) represent the readily biodegradable OC. Therefore, investigating retention mechanisms of LMWOAs in mineral-cation-LMWOAs systems is critical to understanding soil C cycling. Given the general acidic conditions and dominance of kaolinite in tropical soils, we investigated the retention mechanisms of citric acid (CA) in kaolinite-Fe(III)-CA systems with various Fe/CA molar ratios at pH ~3.5 using Fe K-edge EXAFS and L- 3,2-edge XANES techniques. With Fe/CA molar ratios >2, the formed ferrihydrite mainly contributed to CA retention through adsorptionmore » and/or coprecipitation. With Fe/CA molar ratios from 2 to 0.5, ternary complexation of CA to kaolinite via a five-coordinated Fe(III) bridge retained higher CA than ferrihydrite-induced adsorption and/or coprecipitation. With Fe/CA molar ratios ≤ 0.5, kaolinite-Fe(III)-citrate complexation preferentially occurred, but less CA was retained than via outer-sphere kaolinite-CA complexation. This study highlighted the significant impact of varied Fe/CA molar ratios on CA retention mechanisms in kaolinite-Fe(III)-CA systems under acidic conditions, and clearly showed the important contribution of Fe-bridged ternary complexation on CA retention. In conclusion, these findings will enhance our understanding of the dynamics of CA and other LMWOAs in tropical soils.« less

  4. Citric acid production from partly deproteinized whey under non-sterile culture conditions using immobilized cells of lactose-positive and cold-adapted Yarrowia lipolytica B9.

    PubMed

    Arslan, Nazli Pinar; Aydogan, Mehmet Nuri; Taskin, Mesut

    2016-08-10

    The present study was performed to produce citric acid (CA) from partly deproteinized cheese whey (DPCW) under non-sterile culture conditions using immobilized cells of the cold-adapted and lactose-positive yeast Yarrowia lipolytica B9. DPCW was prepared using the temperature treatment of 90°C for 15min. Sodium alginate was used as entrapping agent for cell immobilization. Optimum conditions for the maximum CA production (33.3g/L) in non-sterile DPCW medium were the temperature of 20°C, pH 5.5, additional lactose concentration of 20g/L, sodium alginate concentration of 2%, number of 150 beads/100mL and incubation time of 120h. Similarly, maximum citric acid/isocitric acid (CA/ICA) ratio (6.79) could be reached under these optimal conditions. Additional nitrogen and phosphorus sources decreased CA concentration and CA/ICA ratio. Immobilized cells were reused in three continuous reaction cycles without any loss in the maximum CA concentration. The unique combination of low pH and temperature values as well as cell immobilization procedure could prevent undesired microbial contaminants during CA production. This is the first work on CA production by cold-adapted microorganisms under non-sterile culture conditions. Besides, CA production using a lactose-positive strain of the yeast Y. lipolytica was investigated for the first time in the present study. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Influence of carboxylic acid type on microstructure and magnetic properties of polymeric complex sol-gel driven NiFe2O4

    NASA Astrophysics Data System (ADS)

    Hessien, M. M.; Mostafa, Nasser Y.; Abd-Elkader, Omar H.

    2016-01-01

    Citric, oxalic and tartaric acids were used for synthesis of NiFe2O4 using polymeric complex precursor route. The dry precursor gels were calcined at various temperatures (400-1100 °C) for 2 h. All carboxylic acids produce iron-deficient NiFe2O4 with considerable amount of α-Fe2O3 at 400 °C. Increase in the annealing temperature caused reaction of α-Fe2O3 with iron-deficient ferrite phase. The amount of initially formed α-Fe2O3 is directly correlated with stability constant and inversely correlated with the decomposition temperature of Fe(III) carboxylate precursors. In case of tartaric acid precursor, single phase of the ferrite was obtained at 450 °C. However, in case of oxalic acid and citric acid precursors, single phase ferrite was obtained at 550 °C and 700 °C, respectively. The lattice parameters were increased with increasing annealing temperature and with decreasing the amount of α-Fe2O3. Maximum saturation magnetization (55 emu/g) was achieved using tartaric acid precursor annealed at 1100 °C.

  6. Identification of a Classical Mutant in the Industrial Host Aspergillus niger by Systems Genetics: LaeA Is Required for Citric Acid Production and Regulates the Formation of Some Secondary Metabolites

    PubMed Central

    Niu, Jing; Arentshorst, Mark; Nair, P. Deepa S.; Dai, Ziyu; Baker, Scott E.; Frisvad, Jens C.; Nielsen, Kristian F.; Punt, Peter J.; Ram, Arthur F.J.

    2015-01-01

    The asexual filamentous fungus Aspergillus niger is an important industrial cell factory for citric acid production. In this study, we genetically characterized a UV-generated A. niger mutant that was originally isolated as a nonacidifying mutant, which is a desirable trait for industrial enzyme production. Physiological analysis showed that this mutant did not secrete large amounts of citric acid and oxalic acid, thus explaining the nonacidifying phenotype. As traditional complementation approaches to characterize the mutant genotype were unsuccessful, we used bulk segregant analysis in combination with high-throughput genome sequencing to identify the mutation responsible for the nonacidifying phenotype. Since A. niger has no sexual cycle, parasexual genetics was used to generate haploid segregants derived from diploids by loss of whole chromosomes. We found that the nonacidifying phenotype was caused by a point mutation in the laeA gene. LaeA encodes a putative methyltransferase-domain protein, which we show here to be required for citric acid production in an A. niger lab strain (N402) and in other citric acid production strains. The unexpected link between LaeA and citric acid production could provide new insights into the transcriptional control mechanisms related to citric acid production in A. niger. Interestingly, the secondary metabolite profile of a ΔlaeA strain differed from the wild-type strain, showing both decreased and increased metabolite levels, indicating that LaeA is also involved in regulating the production of secondary metabolites. Finally, we show that our systems genetics approach is a powerful tool to identify trait mutations. PMID:26566947

  7. Identification of a Classical Mutant in the Industrial Host Aspergillus niger by Systems Genetics: LaeA Is Required for Citric Acid Production and Regulates the Formation of Some Secondary Metabolites.

    PubMed

    Niu, Jing; Arentshorst, Mark; Nair, P Deepa S; Dai, Ziyu; Baker, Scott E; Frisvad, Jens C; Nielsen, Kristian F; Punt, Peter J; Ram, Arthur F J

    2015-11-13

    The asexual filamentous fungus Aspergillus niger is an important industrial cell factory for citric acid production. In this study, we genetically characterized a UV-generated A. niger mutant that was originally isolated as a nonacidifying mutant, which is a desirable trait for industrial enzyme production. Physiological analysis showed that this mutant did not secrete large amounts of citric acid and oxalic acid, thus explaining the nonacidifying phenotype. As traditional complementation approaches to characterize the mutant genotype were unsuccessful, we used bulk segregant analysis in combination with high-throughput genome sequencing to identify the mutation responsible for the nonacidifying phenotype. Since A. niger has no sexual cycle, parasexual genetics was used to generate haploid segregants derived from diploids by loss of whole chromosomes. We found that the nonacidifying phenotype was caused by a point mutation in the laeA gene. LaeA encodes a putative methyltransferase-domain protein, which we show here to be required for citric acid production in an A. niger lab strain (N402) and in other citric acid production strains. The unexpected link between LaeA and citric acid production could provide new insights into the transcriptional control mechanisms related to citric acid production in A. niger. Interestingly, the secondary metabolite profile of a ΔlaeA strain differed from the wild-type strain, showing both decreased and increased metabolite levels, indicating that LaeA is also involved in regulating the production of secondary metabolites. Finally, we show that our systems genetics approach is a powerful tool to identify trait mutations. Copyright © 2016 Niu et al.

  8. Identification of a classical mutant in the industrial host Aspergillus niger by systems genetics: LaeA is required for citric acid production and regulates the formation of some secondary metabolites

    DOE PAGES

    Niu, Jing; Arentshorst, Mark; Nair, P. Deepa S.; ...

    2015-11-13

    The asexual filamentous fungus Aspergillus niger is an important industrial cell factory for citric acid production. In this study, we genetically characterized a UV-generated A. niger mutant that was originally isolated as a nonacidifying mutant, which is a desirable trait for industrial enzyme production. Physiological analysis showed that this mutant did not secrete large amounts of citric acid and oxalic acid, thus explaining the nonacidifying phenotype. As traditional complementation approaches to characterize the mutant genotype were unsuccessful, we used bulk segregant analysis in combination with high-throughput genome sequencing to identify the mutation responsible for the nonacidifying phenotype. Since A. nigermore » has no sexual cycle, parasexual genetics was used to generate haploid segregants derived from diploids by loss of whole chromosomes. We found that the nonacidifying phenotype was caused by a point mutation in the laeA gene. LaeA encodes a putative methyltransferase-domain protein, which we show here to be required for citric acid production in an A. niger lab strain (N402) and in other citric acid production strains. The unexpected link between LaeA and citric acid production could provide new insights into the transcriptional control mechanisms related to citric acid production in A. niger. Interestingly, the secondary metabolite profile of a Δ laeA strain differed from the wild-type strain, showing both decreased and increased metabolite levels, indicating that LaeA is also involved in regulating the production of secondary metabolites. As a result, we show that our systems genetics approach is a powerful tool to identify trait mutations.« less

  9. Identification of a classical mutant in the industrial host Aspergillus niger by systems genetics: LaeA is required for citric acid production and regulates the formation of some secondary metabolites

    SciTech Connect

    Niu, Jing; Arentshorst, Mark; Nair, P. Deepa S.

    The asexual filamentous fungus Aspergillus niger is an important industrial cell factory for citric acid production. In this study, we genetically characterized a UV-generated A. niger mutant that was originally isolated as a nonacidifying mutant, which is a desirable trait for industrial enzyme production. Physiological analysis showed that this mutant did not secrete large amounts of citric acid and oxalic acid, thus explaining the nonacidifying phenotype. As traditional complementation approaches to characterize the mutant genotype were unsuccessful, we used bulk segregant analysis in combination with high-throughput genome sequencing to identify the mutation responsible for the nonacidifying phenotype. Since A. nigermore » has no sexual cycle, parasexual genetics was used to generate haploid segregants derived from diploids by loss of whole chromosomes. We found that the nonacidifying phenotype was caused by a point mutation in the laeA gene. LaeA encodes a putative methyltransferase-domain protein, which we show here to be required for citric acid production in an A. niger lab strain (N402) and in other citric acid production strains. The unexpected link between LaeA and citric acid production could provide new insights into the transcriptional control mechanisms related to citric acid production in A. niger. Interestingly, the secondary metabolite profile of a Δ laeA strain differed from the wild-type strain, showing both decreased and increased metabolite levels, indicating that LaeA is also involved in regulating the production of secondary metabolites. As a result, we show that our systems genetics approach is a powerful tool to identify trait mutations.« less

  10. Amelioration of cadmium- and mercury-induced liver and kidney damage in rats by genetically engineered probiotic Escherichia coli Nissle 1917 producing pyrroloquinoline quinone with oral supplementation of citric acid.

    PubMed

    Raghuvanshi, Ruma; Chaudhari, Archana; Kumar, G Naresh

    2016-01-01

    Antioxidants, chelating agents, and probiotics are used to manage the toxic effects of cadmium (Cd) and mercury (Hg). The aim of this study was to investigate the combined effects of antioxidants, chelating agents, and probiotics against heavy metal toxicity. Genetically modified probiotic Escherichia coli Nissle 1917 (EcN-20) producing a potent water soluble antioxidant pyrroloquinoline quinone (PQQ) was supplemented with oral citric acid and compared with another genetically modified probiotic EcN-21 producing PQQ and citric acid against oxidative stress induced by Cd and Hg. Rats were independently given 100 ppm Cd and 80 ppm Hg in drinking water for 4 wk. EcN-20 was found to be more effective than EcN-2 (EcN strain with genomic integration of vgb and gfp genes) with orally given PQQ against oxidative stress induced by Cd and Hg. EcN-20 supplemented with oral citric acid was more effective against Cd and Hg toxicity compared with EcN-2+citric acid (oral), EcN-2+PQQ (oral), EcN-2+PQQ (oral)+citric acid (oral), EcN-20, and EcN-21. However, protection shown by EcN-21 was similar to EcN-20. The combination therapy involving probiotic EcN-20 producing PQQ with citric acid given orally was found to be a moderately effective strategy against toxicity induced by Cd and Hg, whereas the protective effect of EcN-21 was the same as EcN-20. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Evaluation of the smear layer removal and erosive capacity of EDTA, boric acid, citric acid and desy clean solutions: an in vitro study.

    PubMed

    Turk, Tugba; Kaval, Mehmet Emin; Şen, Bilge Hakan

    2015-09-03

    The purpose of this study was to investigate the smear layer removal and erosive capacity of various irrigation solutions with sequential use of NaOCl on instrumented root canal walls. The root canals of single-rooted teeth were instrumented with ProTaper rotary instrument. Then, the teeth were randomly divided into five experimental groups. The root canals were irrigated with one of the following solutions (5 mL/1 min): 5% EDTA, 5% boric acid (BA), a mixture of BA and CA, 2.5% citric acid (CA) and 5% Desy Clean. After irrigating with 2.5% NaOCl and distilled water, the roots were split into two halves and each half was prepared for SEM examination. Representative photographs were taken from each third at x500 and x1000 magnifications. Double blind scoring was performed by two calibrated observers for smear layer and erosion. The scores were statistically analyzed using Kruskal-Wallis, Dunn's post hoc and Spearman's correlation tests (p = 0.05). There were statistically significant differences among the solutions by means of smear layer and erosion (p < 0.05). While 2.5% CA solution was the most effective solution in removal of smear layer, it was also the most erosive solution (p < 0.05). 5% Desy Clean removed smear layer effectively and caused less erosion. There was a negative, but statistically significant correlation between presence of smear layer and erosion (r = -0.684; p < 0.0001). Desy Clean can be a promising agent as an irrigation solution with optimal smear layer removal capacity and less erosive effects.

  12. Impact of fluorescent lighting on the browning potential of model wine solutions containing organic acids and iron.

    PubMed

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

    2018-03-15

    Model wine solutions containing organic acids, individually or combined, and iron(III), were exposed to light from fluorescent lamps or stored in darkness for four hours. (-)-Epicatechin was then added, and the solutions incubated in darkness for 10days. Browning was monitored by UV-visible absorption spectrophotometry and UHPLC-DAD. The pre-irradiated solutions containing tartaric acid exhibited increased yellow/brown coloration compared to the dark controls mainly due to reaction of the tartaric acid photodegradation product glyoxylic acid with (-)-epicatechin to form xanthylium cation pigments. In these solutions, browning decreased as the concentrations of organic acids other than tartaric acid increased. Xanthylium cations were also detected in the pre-irradiated malic acid solution. However, in the malic acid, succinic acid, citric acid and lactic acid solutions, any coloration was mainly due to the production of dehydrodiepicatechin A, which was largely independent of prior light exposure, but strongly affected by the organic acid present. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Effect of multi-wall carbon nanotubes on Cr(VI) reduction by citric acid: Implications for their use in soil remediation.

    PubMed

    Zhang, Yali; Yang, Jiewen; Zhong, Laiyuan; Liu, Liming

    2018-06-06

    The potential application of carbon nanotubes (CNTs) in waste water treatment and their effect on the fate of heavy metals in the environments have attracted wide attention. However, the influence of CNTs on the reduction of Cr(VI) to Cr(III) in soils remains unknown. In this study, Cr(VI) adsorption by carboxylated or hydroxylated multi-walled carbon nanotubes (MWCNT-COOH or MWCNT-OH) was investigated together with their catalytic effect on Cr(VI) reduction by citric acid. Across the initial concentration range examined (5-60 mg/L), the adsorption capacity of Cr(VI) by MWCNT-COOH and MWCNT-OH (pH 5.0) could reach to 8.09 and 7.85 mg/g, respectively. With the decrease in pH, the Cr(VI) adsorption by both MWCNTs increased, while their difference in adsorption capacity became more pronounced, evidenced by that the percentage of Cr(VI) adsorbed by MWCNT-COOH can be 1.3-fold higher than that of MWCNT-OH at a pH of 3.2. The Cr(VI) adsorption kinetics could be well described by pseudo-second-order (R 2  > 0.95) and intra-particle diffusion models (R 2  > 0.98). MWCNT-OH or MWCNT-COOH could accelerate the reduction of 0.1 mM Cr(VI) by 1.0 mM citric acid, with the first-order rate constant of 0.0325 and 0.0147 h -1 , respectively. This finding was explained as that the reactivity of citric acid might be enhanced with its adsorption on the MWCNT surfaces. The catalysis of the functionalized CNTs on the Cr(VI) reduction was inhibited as the pH increased. The addition of MWCNTs to an oxisol can enhance the Cr(VI) reduction because the final concentration of aqueous Cr(III), compared with that without addition of MWCNTs, increased from 20.7 to 32.6 μM. Meanwhile, re-adsorption of aqueous Cr(III) onto the solid surfaces was also observed. The results above are important for understanding on the effect of CNTs on the fate of Cr(VI) and how they can be used to remediate Cr(VI)-polluted soils.

  14. Complementary approaches for the evaluation of biocompatibility of 90Y-labeled superparamagnetic citric acid (Fe,Er)3O4 coated nanoparticles.

    PubMed

    Antic, Bratislav; Boskovic, Marko; Nikodinovic-Runic, Jasmina; Ming, Yue; Zhang, Hongguo; Bozin, Emil S; Janković, Drina; Spasojevic, Vojislav; Vranjes-Djuric, Sanja

    2017-06-01

    Magnetic nanoparticles (MNPs) are of immense interest for diagnostic and therapeutic applications in medicine. Design and development of new iron oxide-based MNPs for such applications is of rather limited breadth without reliable and sensitive methods to determine their levels in body tissues. Commonly used methods, such as ICP, are quite problematic, due to the inability to decipher the origin of the detected iron, i.e. whether it originates from the MNPs or endogenous from tissues and bodily fluids. One of the approaches to overcome this problem and to increase reliability of tracing MNPs is to partially substitute iron ions in the MNPs with Er. Here, we report on the development of citric acid coated (Fe,Er) 3 O 4 nanoparticles and characterization of their physico-chemical and biological properties by utilization of various complementary approaches. The synthesized MNPs had a narrow (6-7nm) size distribution, as consistently seen in atomic pair distribution function, transmission electron microscopy, and DC magnetization measurements. The particles were found to be superparamagnetic, with a pronounced maximum in measured zero-field cooled magnetization at around 90K. Reduction in saturation magnetization due to incorporation of 1.7% Er 3+ into the Fe 3 O 4 matrix was clearly observed. From the biological standpoint, citric acid coated (Fe,Er) 3 O 4 NPs were found to induce low toxicity both in human cell fibroblasts and in zebrafish (Danio rerio) embryos. Biodistribution pattern of the MNPs after intravenous administration in healthy Wistar rats was followed by the radiotracer method, revealing that 90 Y-labeled MNPs were predominantly found in liver (75.33% ID), followed by lungs (16.70% ID) and spleen (2.83% ID). Quantitative agreement with these observations was obtained by ICP-MS elemental analysis using Er as the detected tracer. Based on the favorable physical, chemical and biological characteristics, citric acid coated (Fe,Er) 3 O 4 MNPs could be

  15. Complementary approaches for the evaluation of biocompatibility of 90Y-labeled superparamagnetic citric acid (Fe,Er) 3O 4 coated nanoparticles

    SciTech Connect

    Antic, Bratislav; Boskovic, Marko; Nikodinovic-Runic, Jasmina

    Magnetic nanoparticles (MNPs) are of immense interest for diagnostic and therapeutic applications in medicine. Design and development of new iron oxide-based MNPs for such applications is of rather limited breadth without reliable and sensitive methods to determine their levels in body tissues. Commonly used methods, such as ICP, are quite problematic, due to the inability to decipher the origin of the detected iron, i.e. whether it originates from the MNPs or endogenous from tissues and bodily fluids. One of the approaches to overcome this problem and to increase reliability of tracing MNPs is to partially substitute iron ions in themore » MNPs with Er. Here, we report on the development of citric acid coated (Fe,Er) 3O 4 nanoparticles and characterization of their physico-chemical and biological properties by utilization of various complementary approaches. The synthesized MNPs had a narrow (6–7 nm) size distribution, as consistently seen in atomic pair distribution function, transmission electron microscopy, and DC magnetization measurements. The particles were found to be superparamagnetic, with a pronounced maximum in measured zero-field cooled magnetization at around 90 K. Reduction in saturation magnetization due to incorporation of 1.7% Er 3+ into the Fe 3O 4 matrix was clearly observed. From the biological standpoint, citric acid coated (Fe,Er) 3O 4 NPs were found to induce low toxicity both in human cell fibroblasts and in zebrafish ( Danio rerio) embryos. Biodistribution pattern of the MNPs after intravenous administration in healthy Wistar rats was followed by the radiotracer method, revealing that 90Y-labeled MNPs were predominantly found in liver (75.33% ID), followed by lungs (16.70% ID) and spleen (2.83% ID). Quantitative agreement with these observations was obtained by ICP-MS elemental analysis using Er as the detected tracer. Based on the favorable physical, chemical and biological characteristics, citric acid coated (Fe,Er) 3O 4 MNPs could

  16. Complementary approaches for the evaluation of biocompatibility of 90Y-labeled superparamagnetic citric acid (Fe,Er) 3O 4 coated nanoparticles

    DOE PAGES

    Antic, Bratislav; Boskovic, Marko; Nikodinovic-Runic, Jasmina; ...

    2017-02-10

    Magnetic nanoparticles (MNPs) are of immense interest for diagnostic and therapeutic applications in medicine. Design and development of new iron oxide-based MNPs for such applications is of rather limited breadth without reliable and sensitive methods to determine their levels in body tissues. Commonly used methods, such as ICP, are quite problematic, due to the inability to decipher the origin of the detected iron, i.e. whether it originates from the MNPs or endogenous from tissues and bodily fluids. One of the approaches to overcome this problem and to increase reliability of tracing MNPs is to partially substitute iron ions in themore » MNPs with Er. Here, we report on the development of citric acid coated (Fe,Er) 3O 4 nanoparticles and characterization of their physico-chemical and biological properties by utilization of various complementary approaches. The synthesized MNPs had a narrow (6–7 nm) size distribution, as consistently seen in atomic pair distribution function, transmission electron microscopy, and DC magnetization measurements. The particles were found to be superparamagnetic, with a pronounced maximum in measured zero-field cooled magnetization at around 90 K. Reduction in saturation magnetization due to incorporation of 1.7% Er 3+ into the Fe 3O 4 matrix was clearly observed. From the biological standpoint, citric acid coated (Fe,Er) 3O 4 NPs were found to induce low toxicity both in human cell fibroblasts and in zebrafish ( Danio rerio) embryos. Biodistribution pattern of the MNPs after intravenous administration in healthy Wistar rats was followed by the radiotracer method, revealing that 90Y-labeled MNPs were predominantly found in liver (75.33% ID), followed by lungs (16.70% ID) and spleen (2.83% ID). Quantitative agreement with these observations was obtained by ICP-MS elemental analysis using Er as the detected tracer. Based on the favorable physical, chemical and biological characteristics, citric acid coated (Fe,Er) 3O 4 MNPs could

  17. Inhibition of lipid oxidation in frozen farmed ovate pompano (Trachinotus ovatus L.) fillets stored at -18 °C by chitosan coating incorporated with citric acid or licorice extract.

    PubMed

    Qiu, Xujian; Chen, Shengjun; Liu, Guangming; Lin, Hong

    2016-08-01

    Lipid oxidation can occur in fish fillets during long-term frozen storage and cause quality and nutrition loss, which is a major concern in the seafood industry. Our previous study showed that chitosan combined with citric acid or licorice extract can have a preserving effect on fresh fish fillets stored at 4 °C. It is of interest to further study their antioxidant effects on fish fillets during frozen storage. Chitosan, chitosan and citric acid, chitosan and licorice extract can inhibit primary and secondary lipid oxidation, as indicated by lower peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) values compared to the control samples. In addition, drip loss was decreased in the treatment samples. Both citric acid and licorice extract enhanced the antioxidant effects of chitosan. Among all the three treatments, chitosan and licorice extract showed the best antioxidant effects, reducing both PV and TBARS significantly at the end of storage. The combination of chitosan and citric acid or licorice extract showed significant antioxidant effects on ovate pompano fillets at -18 °C during 6 months of storage. They could be applied as natural antioxidant preservatives for use in seafood products or other meat products. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

  18. 21 CFR 582.1099 - Tartaric acid.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ..., FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE General Purpose Food Additives § 582... recognized as safe when used in accordance with good manufacturing or feeding practice. ...

  19. Showing Enantiomorphous Crystals of Tartaric Acid

    ERIC Educational Resources Information Center

    Andrade-Gamboa, Julio

    2007-01-01

    Most of the articles and textbooks that show drawings of enantiomorphous crystals use an inadequate view to appreciate the fact that they are non-superimposable mirror images of one another. If a graphical presentation of crystal chirality is not evident, the main attribute of crystal enantiomorphism can not be recognized by students. The classic…

  20. 21 CFR 582.1099 - Tartaric acid.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ..., FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE General Purpose Food Additives § 582... recognized as safe when used in accordance with good manufacturing or feeding practice. ...

  1. 21 CFR 582.1099 - Tartaric acid.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ..., FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE General Purpose Food Additives § 582... recognized as safe when used in accordance with good manufacturing or feeding practice. ...

  2. 21 CFR 582.1099 - Tartaric acid.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ..., FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE General Purpose Food Additives § 582... recognized as safe when used in accordance with good manufacturing or feeding practice. ...

  3. 21 CFR 582.1099 - Tartaric acid.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ..., FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE General Purpose Food Additives § 582... recognized as safe when used in accordance with good manufacturing or feeding practice. ...

  4. Solid-phase synthesis of graphene quantum dots from the food additive citric acid under microwave irradiation and their use in live-cell imaging.

    PubMed

    Zhuang, Qianfen; Wang, Yong; Ni, Yongnian

    2016-05-01

    The work demonstrated that solid citric acid, one of the most common food additives, can be converted to graphene quantum dots (GQDs) under microwave heating. The as-prepared GQDs were further characterized by various analytical techniques like transmission electron microscopy, atomic force microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, fluorescence and UV-visible spectroscopy. Cytotoxicity of the GQDs was evaluated using HeLa cells. The result showed that the GQDs almost did not exhibit cytotoxicity at concentrations as high as 1000 µg mL(-1). In addition, it was found that the GQDs showed good solubility, excellent photostability, and excitation-dependent multicolor photoluminescence. Subsequently, the multicolor GQDs were successfully used as a fluorescence light-up probe for live-cell imaging. Copyright © 2015 John Wiley & Sons, Ltd.

  5. Structural and cyclic volta metric investigations on BIPBVOX solid electrolyte synthesized by ethylene glycol–citric acid sol–gel route

    SciTech Connect

    Naqvi, Faria K.; Beg, Saba, E-mail: profsababeg@gmail.com; Al-Areqi, Niyazi A. S.

    Samples of BIPBVOX.x (Bi{sub 2}V{sub 1–x}Pb{sub x}O{sub 5.5–x/2}) in the composition range 0.05 ≤ x ≤ 0.20 were prepared by ethylene glycol– citric acid sol–gel synthesis route. Structural investigations were carried out by X–ray diffraction, DTA. The highly conducting γ′– phase was effectively stabilized at room temperature for compositions with x ≥ 0.17. Cyclic voltammetric measurements showed reversible redox reactions of vanadium and irreversible redox reaction of Bi{sup 3+} in the BIPBVOX system during the first cathodic and anodic sweep. However, a higher stability against the reduction of Bi{sup 3+} to metallic bismuth was seen for x=0.20.

  6. Effect of the temperature and the CO2 concentration on the behaviour of the citric acid as a scale inhibitor of CaCO3

    NASA Astrophysics Data System (ADS)

    Blanco, K.; Aponte, H.; Vera, E.

    2017-12-01

    For all Industrial sector is important to extend the useful life of the materials that they use in their process, the scales of CaCO3 are common in situation where fluids are handled with high concentration of ions and besides this temperatures and CO2 concentration dissolved, that scale generates large annual losses because there is a reduction in the process efficiency or corrosion damage under deposit, among other. In order to find new alternatives to this problem, the citric acid was evaluated as scale of calcium carbonate inhibition in critical condition of temperature and concentration of CO2 dissolved. Once the results are obtained it was carried out the statistical evaluation in order to generate an equation that allow to see that behaviour, giving as result, a good efficiency of inhibition to the conditions evaluated the scales of products obtained were characterized through scanning electron microscopy.

  7. Kinetics of moisture-induced hydrolysis in powder blends stored at and below the deliquescence relative humidity: investigation of sucrose-citric acid mixtures.

    PubMed

    Kwok, Kaho; Mauer, Lisa J; Taylor, Lynne S

    2010-11-24

    Previous studies have shown that deliquescent organic compounds frequently exhibit chemical instability when stored in environmental conditions above their deliquescence relative humidity (RH). The goal of the current study was to investigate the effect of atmospheric moisture on the long-term chemical stability of crystalline sucrose-citric acid mixtures following storage at RHs at and below the mutual deliquescence relative humidity (MDRH). Interestingly, it was found that sucrose hydrolysis can occur below the MDRH of 64% and was observed for samples stored at 54% RH. However, hydrolysis was not seen for samples stored at 33 or 43% RH. The rate of sucrose hydrolysis could be modeled by taking into account the rate and extent of moisture uptake, which in turn was dependent on the composition of the powder and the storage RH. A reaction mechanism initiated by capillary condensation and involving additional deliquescence lowering by the degradation products formed as a result of sucrose hydrolysis (glucose and fructose) was proposed.

  8. Effect of EDTA, EDDS, NTA and citric acid on electrokinetic remediation of As, Cd, Cr, Cu, Ni, Pb and Zn contaminated dredged marine sediment.

    PubMed

    Song, Yue; Ammami, Mohamed-Tahar; Benamar, Ahmed; Mezazigh, Salim; Wang, Huaqing

    2016-06-01

    In recent years, electrokinetic (EK) remediation method has been widely considered to remove metal pollutants from contaminated dredged sediments. Chelating agents are used as electrolyte solutions to increase metal mobility. This study aims to investigate heavy metal (HM) (As, Cd, Cr, Cu, Ni, Pb and Zn) mobility by assessing the effect of different chelating agents (ethylenediaminetetraacetic acid (EDTA), ethylenediaminedisuccinic acid (EDDS), nitrilotriacetic acid (NTA) or citric acid (CA)) in enhancing EK remediation efficiency. The results show that, for the same concentration (0.1 mol L(-1)), EDTA is more suitable to enhance removal of Ni (52.8 %), Pb (60.1 %) and Zn (34.9 %). EDDS provides effectiveness to increase Cu removal efficiency (52 %), while EDTA and EDDS have a similar enhancement removal effect on As EK remediation (30.5∼31.3 %). CA is more suitable to enhance Cd removal (40.2 %). Similar Cr removal efficiency was provided by EK remediation tests (35.6∼43.5 %). In the migration of metal-chelate complexes being directed towards the anode, metals are accumulated in the middle sections of the sediment matrix for the tests performed with EDTA, NTA and CA. But, low accumulation of metal contamination in the sediment was observed in the test using EDDS.

  9. Proposed formation mechanism and active species of hydrogen molecules generated from a novel magnesium-citric acid-hydroxypropyl cellulose coating (MgCC) material

    NASA Astrophysics Data System (ADS)

    Kobayashi, Shigeki; Chikuma, Toshiyuki; Chiba, Kazuyoshi; Tsuchiya, Daisuke; Hirai, Tomomitsu

    2016-02-01

    The presence of acids is known to accelerate the reaction (Mg + 2H2O = Mg(OH)2 + H2). We developed a novel Mg-citric acid coating (MgCC) material produced by milling Mg powder coated with hydroxypropyl cellulose (HPC); because of its H2 generation, this material could be used in antioxidant therapy and antiaging applications. After milling in the presence of citric acid, this material produced H2-rich water upon addition to cooled water. Although the reaction was considered to involve a two-electron transfer from Mg to 2H2O, the role of the acid in H2 generation remains incompletely understood. To clarify the reaction mechanism, we performed studies on the deuterium kinetic isotope effects (KIE) and electron spin resonance (ESR). We observed differences in the concentration ratios, such as H2/D2 > 1 and H2/(H2 + D2 + HD) > 1, involved in H2, D2, and (H2 + D2 + HD) production, and found that adducts with hydrogen atoms (Hrad) were not obtained from the spin-trapping reaction between 5-(2, 2-Dimethyl-1,3-propoxy cyclophosphoryl)-5-methyl-1-pyrroline N-oxide (CYPMPO) and the MgCC material. The H2, D2, and HD produced from MgCC were identified by using a gas chromatograph connected to a mass spectrometer. The spin-trapping techniques showed that the Hrad adducts formed by the reaction of NaBH4 with CYPMPO could not be observed from reaction of MGCC with CYPMPO in H2O. The data suggest that the rate-controlling step and proposed transition state (TS) exist in the reaction pathway of the O-H bond cleavage and H-H bond formation. A TS of a structure such as [Mg(OH2)2]∗ could be expected in the reaction pathway between Mg and 2H2O by density functional theory calculations. Also, these results show that H2 generation is accelerated in the presence of acids because the activation energy of the TS is significantly smaller than that of H2O.

  10. Determination of alpha-hydroxy acids in cosmetic products by high-performance liquid chromatography with a narrow-bore column.

    PubMed

    Nicoletti, I; Corradini, C; Cogliandro, E; Cavazza, A

    1999-08-01

    This paper reports the results of a study carried out to develop a simple, rapid and sensitive method for the separation, identification and quantitative measurement of alpha-hydroxy acids in commercial cosmetics using high-performance liquid chromatography (HPLC). This method is successfully applied to the simultaneous identification and quantitative determination of glycolic, lactic, malic, tartaric and citric acids employing a reversed phase narrow-bore column under isocratic condition and UV detection. The method is validated by determining the precision of replicate analyses and accuracy by analyzing samples with and without adding know amount of the alpha-hydroxy acids. The procedure is suitable for routine analyses of commercial cosmetics.

  11. Effects of Continuous Triiodothyronine Infusion on Citric Acid Cycle in the Normal Immature Swine Heart under Extracorporeal Membrane Oxygenation in vivo

    SciTech Connect

    Kajimoto, Masaki; O'Kelly-Priddy, Colleen M.; Ledee, Dolena R.

    Extracorporeal membrane oxygenation (ECMO) is frequently used in infants with postoperative cardiopulmonary failure. ECMO also suppresses circulating triiodothyronine (T 3) levels and modifies myocardial metabolism. We assessed the hypothesis that T 3 supplementation reverses ECMO induced metabolic abnormalities in the immature heart. Twenty-two male Yorkshire pigs (age 25-38 days) with ECMO were received [2- 13C]lactate, [2,4,6,8- 13C]octanoate (medium chain fatty acid) and [U- 13C]long-chain fatty acids as metabolic tracers either systemically (totally physiological intracoronary concentration) or directly into the coronary artery (high substrate concentration) for the last 60 minutes of each protocol. Nuclear magnetic resonance (NMR) analysis of left ventricularmore » tissue determined the fractional contribution (Fc) of these substrates to the citric acid cycle (CAC). Fifty percent of the pigs in each group received intravenous T 3 supplement (bolus at 0.6 μg/kg and then continuous infusion at 0.2 μg/kg/hour) during ECMO. Under both substrate loading conditions T 3 significantly increased lactate-Fc with a marginal increase in octanoate-Fc. Both T 3 and high substrate provision increased myocardial energy status indexed by [Phosphocreatine]/[ATP]. In conclusion, T 3 supplementation promoted lactate metabolism to the CAC during ECMO suggesting that T 3 releases inhibition of pyruvate dehydrogenase. Manipulation of substrate utilization by T 3 may be used therapeutically during ECMO to improve resting energy state and facilitate weaning.« less

  12. Resolution of 1-n-butyl-3-methyl-3-phospholene 1-oxide with TADDOL derivatives and calcium salts of O,O'-Dibenzoyl-(2R,3R)- or O,O'-di-p-toluoyl-(2R,3R)-tartaric acid.

    PubMed

    Bagi, Péter; Fekete, András; Kállay, Mihály; Hessz, Dóra; Kubinyi, Miklós; Holczbauer, Tamás; Czugler, Mátyás; Fogassy, Elemér; Keglevich, György

    2014-03-01

    The resolution methods applying (-)-(4R,5R)-4,5-bis(diphenylhydroxymethyl)-2,2-dimethyldioxolane ("TADDOL"), (-)-(2R,3R)-α,α,α',α'-tetraphenyl-1,4-dioxaspiro[4.5]decan-2,3-dimethanol ("spiro-TADDOL"), as well as the acidic and neutral Ca(2+) salts of (-)-O,O'-dibenzoyl- and (-)-O,O'-di-p-toluoyl-(2R,3R)-tartaric acid were extended for the preparation of 1-n-butyl-3-methyl-3-phospholene 1-oxide in optically active form. In one case, the intermediate diastereomeric complex could be identified by single-crystal X-ray analysis. The absolute P-configuration of the enantiomers of the phospholene oxide was also determined by comparing the experimentally obtained and calculated CD spectra. © 2014 Wiley Periodicals, Inc.

  13. Confocal laser scanning microscopy and area-scale analysis used to quantify enamel surface textural changes from citric acid demineralization and salivary remineralization in vitro.

    PubMed

    Austin, R S; Giusca, C L; Macaulay, G; Moazzez, R; Bartlett, D W

    2016-02-01

    This paper investigates the application of confocal laser scanning microscopy to determine the effect of acid-mediated erosive enamel wear on the micro-texture of polished human enamel in vitro. Twenty polished enamel samples were prepared and subjected to a citric acid erosion and pooled human saliva remineralization model. Enamel surface microhardness was measured using a Knoop hardness tester, which confirmed that an early enamel erosion lesion was formed which was then subsequently completely remineralized. A confocal laser scanning microscope was used to capture high-resolution images of the enamel surfaces undergoing demineralization and remineralization. Area-scale analysis was used to identify the optimal feature size following which the surface texture was determined using the 3D (areal) texture parameter Sa. The Sa successfully characterized the enamel erosion and remineralization for the polished enamel samples (P<0.001). Areal surface texture characterization of the surface events occurring during enamel demineralization and remineralization requires optical imaging instrumentation with lateral resolution <2.5 μm, applied in combination with appropriate filtering in order to remove unwanted waviness and roughness. These techniques will facilitate the development of novel methods for measuring early enamel erosion lesions in natural enamel surfaces in vivo. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  14. Sedimentation field-flow fractionation for characterization of citric acid-modified Hβ zeolite particles: Effect of particle dispersion and carrier composition.

    PubMed

    Dou, Haiyang; Bai, Guoyi; Ding, Liang; Li, Yueqiu; Lee, Seungho

    2015-11-27

    In this study, sedimentation field-flow fractionation (SdFFF) was, for the first time, applied for determination of size distribution of Hβ zeolite particles modified by citric acid (CA-Hβ). Effects of the particle dispersion and the carrier liquid composition (type of dispersing reagent (surfactant) and salt added in the carrier liquid, ionic strength, and pH) on SdFFF elution behavior of CA-Hβ zeolite particles were systematically investigated. Also the SdFFF separation efficiency of the particles was discussed in terms of the forces such as van der Waals, hydrophobic, and induced-dipole interactions. Results reveal that the type of salt and pH of the carrier liquid significantly affect the SdFFF separation efficiency of the zeolite particles. It was found that addition of a salt (NaN3) into the carrier liquid affects the characteristic of the SdFFF channel surface. It was found that the use of an acidic medium (pH 3.2) leads to a particle-channel interaction, while the use of a basic medium (pH 10.6) promotes an inter-particle hydrophobic interaction. Result from SdFFF was compared with those from scanning electron microscopy (SEM) and dynamic light scattering (DLS). It seems that, once the experimental conditions are optimized, SdFFF becomes a valuable tool for size characterization of the zeolite particles. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Effect of different pH conditions on the in vitro digestibility and physicochemical properties of citric acid-treated potato starch.

    PubMed

    Lee, Soo Yoon; Lee, Kwang Yeon; Lee, Hyeon Gyu

    2018-02-01

    The objective of this study was to investigate the influence of citric acid (CA) treatment (10, 20, and 30% of dry starch weight) under different pH conditions (3.5, 4.5, and 5.5) on the physicochemical properties, in vitro digestibility and prebiotic effects of potato starch. With the CA content increased, the degree of substitution of CA-starch treated at pH 3.5 and 4.5 wad significantly increased i.e. from 0.125 to 0.418 and from 0.078 to 0.167, respectively (p<0.05), except for starch treated at pH 5.5 (from 0.023 to 0.030). The resistant starch (RS) content of CA-starch was effectively increased compared to pH control made by changing pH from 3.5 to 5.5 with hydrochloric acid alone. The results of X-ray diffraction and swelling power were affected by pH condition, whereas they were less affected by the percentage of CA. Swelling power of treated starch also significantly decreased as the pH level decreased (p<0.05). Probiotic bacteria B. bifidum and L. acidophilus grown in medium with citrate starch showed substantial viability. These results suggest that pH conditions of CA modification substantially affect the degree of CA substitution, physicochemical properties, and nutritional value. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Solid-state thermal behavior and stability studies of theophylline-citric acid cocrystals prepared by neat cogrinding or thermal treatment

    SciTech Connect

    Hsu, Po-Chun; Lin, Hong-Liang; Wang, Shun-Li, E-mail: wangshunli@mail.ncyu.edu.tw

    To investigate the thermal behavior of cocrystal formed between anhydrous theophylline (TP) and anhydrous citric acid (CA) by neat manual cogrinding or thermal treatment, DSC and FTIR microspectroscopy with curve-fitting analysis were applied. The physical mixture and 60-min ground mixture were stored at 55{+-}0.5 Degree-Sign C/40{+-}2% RH condition to determine their stability behavior. Typical TP-CA cocrystals were prepared by slow solvent evaporation method. Results indicate that the cogrinding process could gradually induce the cocrystal formation between TP and CA. The IR spectral peak shift from 3495 to 3512 cm{sup -1} and the stepwise appearance of several new IR peaks atmore » 1731, 1712, 1676, 1651, 1557 and 1265 cm{sup -1} with cogrinding time suggest that the mechanism of TP-CA cocrystal formation was evidenced by interacting TP with CA through the intermolecular O-H{center_dot}{center_dot}{center_dot}O hydrogen bonding. The stability of 60-min ground mixture of TP-CA was confirmed at 55{+-}0.5 Degree-Sign C/40{+-}2% RH condition over a storage time of 60 days. - Garphical abstract: Cogrinding, thermal and solvent-evaporation methods might easily induce the theophylline-citric acid cocrystal formation. Highlights: Black-Right-Pointing-Pointer Cogrinding process could gradually induce the cocrystal formation between TP and CA. Black-Right-Pointing-Pointer The TP-CA cocrystal was formed through the intermolecular O-H{center_dot}{center_dot}{center_dot}O hydrogen bonding. Black-Right-Pointing-Pointer The 60-min TP-CA ground mixture was similar to the solvent-evaporated cocrystal. Black-Right-Pointing-Pointer The thermal-induced TP-CA cocrystal formation was confirmed by pre-heating the physical mixture to 152 Degree-Sign C. Black-Right-Pointing-Pointer The 60-min TP-CA ground mixture was stable at accelerated condition over a storage time of 60 days.« less

  17. Citric acid assisted Fenton-like process for enhanced dewaterability of waste activated sludge with in-situ generation of hydrogen peroxide.

    PubMed

    Xiao, Keke; Pei, Kangyue; Wang, Hui; Yu, Wenbo; Liang, Sha; Hu, Jingping; Hou, Huijie; Liu, Bingchuan; Yang, Jiakuan

    2018-09-01

    Fenton's reagent has been widely used to enhance sludge dewaterability. However, drawbacks associated with hydrogen peroxide (H 2 O 2 ) in Fenton's reagents exist, since it is a hazardous chemical and shows carcinogenicity, explosivity, instability, and corrosivity. Moreover, initial acidification and subsequent neutralization are needed as optimal conditions for homogeneous Fenton conditioning and final filtrate discharge. In this study, a Fenton-like process for the enhanced dewaterability of waste activated sludge with in-situ generation of H 2 O 2 and without extra pH adjustment was firstly proposed, namely citric acid (CA)-assisted oxygen activation in an air/nano zero-valent iron (nZVI) system and chemical re-coagulation with polydiallyldimethylammonium chloride (PDMDAAC). Using the response surface methodology (RSM), the optimal doses of CA, nZVI, and PDMDAAC were determined to be 13, 33, and 9 mg g -1 dry solids (DS), respectively. This composite conditioner showed a good dewatering capability compared with the raw sludge, e.g. the capillary suction time decreased from 130.0 to 9.5 s. The enhanced sludge dewaterability was further confirmed by laboratory-scale diaphragm filter press dewatering tests, which produced a lower cake moisture content compared with the raw sludge, and the final pH of the filtrate was close to neutrality. The citric acid promoted the production of H 2 O 2 and Fe(II)/Fe(III) species, the degradation of protein in tightly-bound extracellular polymeric substances, and the decomposition of protein-N in the solid phase of sludge, resulting a greater conversion of bound water to free water. The results of electron spin resonance indicated that the hydroxyl radicals were mainly responsible for the decomposition of proteinaceous compounds. The subsequent chemical re-coagulation with PDMDAAC can make the zeta potential of sludge samples less negative, reduce the repulsive electrostatic interactions, and agglomerate the smaller

  18. Oligosaccharide-based Surfactant/Citric Acid Buffer System Stabilizes Lactate Dehydrogenase during Freeze-drying and Storage without the Addition of Natural Sugar.

    PubMed

    Ogawa, Shigesaburo; Kawai, Ryuichiro; Koga, Maito; Asakura, Kouichi; Takahashi, Isao; Osanai, Shuichi

    2016-06-01

    Experiments were conducted to assess the maintenance effects of oligosaccharide-based surfactants on the enzymatic activity of a model protein, lactate dehydrogenase (LDH), during freeze-drying and room temperature storage using the citric acid buffer system. Oligosaccharide-based surfactants, which exhibit a high glass transition temperature (Tg), promoted the eminent retention of enzymatic activity during these protocols, whereas monosaccharide-based surfactants with a low Tg displayed poor performance at high concentration, albeit much better than that of Tween 80 at middle concentration. The increase in the alkyl chain length did not exert positive effects as observed for the maintenance effect during freeze-thawing, but an amphiphilic nature and a glass forming ability were crucial for the effective stabilization at a low excipient concentration during freeze-drying. Even a low oligosaccharide-based surfactant content (0.1 mg mL(-1)) could maintain LDH activity during freeze-drying, but a high surfactant content (1.0 mg mL(-1)) was required to prevent buffer precipitation and retain high LDH activity on storage. Regarding storage, glass formation restricted molecular mobility in the lyophilized matrix, and LDH activity was effectively retained. The present results describe a strategy based on the glass-forming ability of surfactant-type excipients that affords a natural sugar-free formulation or an alternative use for polysorbate-type surfactants.