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Sample records for citric acid esters

  1. Safety Assessment of Citric Acid, Inorganic Citrate Salts, and Alkyl Citrate Esters as Used in Cosmetics.

    Science.gov (United States)

    Fiume, Monice M; Heldreth, Bart A; Bergfeld, Wilma F; Belsito, Donald V; Hill, Ronald A; Klaassen, Curtis D; Liebler, Daniel C; Marks, James G; Shank, Ronald C; Slaga, Thomas J; Snyder, Paul W; Andersen, F Alan

    2014-05-26

    The CIR Expert Panel (Panel) assessed the safety of citric acid, 12 inorganic citrate salts, and 20 alkyl citrate esters as used in cosmetics, concluding that these ingredients are safe in the present practices of use and concentration. Citric acid is reported to function as a pH adjuster, chelating agent, or fragrance ingredient. Some of the salts are also reported to function as chelating agents, and a number of the citrates are reported to function as skin-conditioning agents but other functions are also reported. The Panel reviewed available animal and clinical data, but because citric acid, calcium citrate, ferric citrate, manganese citrate, potassium citrate, sodium citrate, diammonium citrate, isopropyl citrate, stearyl citrate, and triethyl citrate are generally recognized as safe direct food additives, dermal exposure was the focus for these ingredients in this cosmetic ingredient safety assessment.

  2. Use of citric acid esters as alternative fuel for diesel engines

    Energy Technology Data Exchange (ETDEWEB)

    Huber, Georg; Thuneke, Klaus; Remmele, Edgar [Technologie- und Foerderzentrum, Straubing (Germany); Schieder, Doris [Technische Univ. Muenchen, Straubing (Germany). Lehrstuhl fuer Chemie Biogener Rohstoffe

    2013-06-01

    Common fuels for (adapted) diesel engines are fossil diesel fuel, fatty acid methyl ester (FAME or biodiesel) or vegetable oils. Furthermore the citric acid esters tributylcitrate (TBC) and triethylcitrate (TEC) are expected to be a possible diesel substitute. Their use as fuel was applied for a patent in Germany in 2010. According to the patent applicant the advantages are low soot combustion, independence of energy imports due to the possibility of local production and a broad raw material base. Their fuel properties have been analysed in the laboratory and compared with the relevant fuel standards. Only some of the determined values are meeting the specifications, but on the other hand few rapeseed oil characteristics (e. g. oxidation stability and viscosity) can be improved if the citric acid esters are used as a blend component. The operating and emission behaviour of a vegetable oil compatible CHP unit fuelled with various rapeseed oil and TBC blends were investigated and a trouble free and soot emission reduced engine operation due to the high molecularly bound oxygen content was observed. Long term test runs are necessary for an entire technical validation. (orig.)

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

    Science.gov (United States)

    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 emulsifier decreased the intestinal absorption of lipids.

  4. Dipropionylcysteine ethyl ester compensates for loss of citric acid cycle intermediates during post ischemia reperfusion in the pig heart.

    Science.gov (United States)

    Kasumov, Takhar; Sharma, Naveen; Huang, Hazel; Kombu, Rajan S; Cendrowski, Andrea; Stanley, William C; Brunengraber, Henri

    2009-12-01

    During reperfusion, following myocardial ischemia, uncompensated loss of citric acid cycle (CAC) intermediates may impair CAC flux and energy transduction. Propionate has an anaplerotic effect when converted to the CAC intermediate succinyl-CoA, and may improve contractile recovery during reperfusion. Antioxidant therapy with N-acetylcysteine decreases reperfusion injury. To synergize the antioxidant effects of cysteine with the anaplerotic effects of propionate, we synthesized a novel bi-functional compound, N,S-dipropionyl cysteine ethyl ester (DPNCE) and tested its anaplerotic and anti-oxidative capacity in anesthetized pigs. Ischemia was induced by a 70% reduction in left anterior descending coronary artery flow for one hour, followed by 1 h of reperfusion. After 30 min of ischemia and throughout reperfusion animals were treated with saline or intravenous DPNCE (1.5 mg x kg(-1) x min(-1), n = 8/group). Arterial concentrations and myocardial propionate, cysteine, free fatty acids, glucose and lactate uptakes, cardiac mechanical functions, myocardial content of CAC intermediates and oxidative stress were assessed. Ischemia resulted in reduction in myocardial tissue concentration of CAC intermediates. DPNCE treatment elevated arterial propionate and cysteine concentrations and myocardial propionate uptake, and increased myocardial concentrations of citrate, succinate, fumarate, and malate compared to saline treated animals. DPNCE treatment did not affect blood pressure or myocardial contractile function, but increased arterial free fatty acid concentration and myocardial fatty acid uptake. Arterial cysteine concentration was elevated by DPNCE, but there was negligible myocardial cysteine uptake, and no change in markers of oxidative stress. DPNCE elevated arterial cysteine and propionate, and increased myocardial concentration of CAC intermediates, but did not affect mechanical function or oxidative stress.

  5. Citric acid production patent review.

    Science.gov (United States)

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

    2008-01-01

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

  6. Biotechnological production of citric acid

    National Research Council Canada - National Science Library

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

    2010-01-01

    This work provides a review about the biotechnological production of citric acid starting from the physicochemical properties and industrial applications, mainly in the food and pharmaceutical sectors...

  7. Biotechnological production of citric acid

    Directory of Open Access Journals (Sweden)

    Belén Max

    2010-12-01

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

  8. 21 CFR 582.6033 - Citric acid.

    Science.gov (United States)

    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...

  9. 21 CFR 582.1033 - Citric acid.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 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...

  10. BNL Citric Acid Technology: Pilot Scale Demonstration

    Energy Technology Data Exchange (ETDEWEB)

    FRANCIS, A J; DODGE,; J, C; GILLOW, J B; FORRESTER, K E

    1999-09-24

    The objective of this project is to remove toxic metals such as lead and cadmium from incinerator ash using the Citric Acid Process developed at Brookhaven National Laboratory. In this process toxic metals in bottom ash from the incineration of municipal solid waste were first extracted with citric acid followed by biodegradation of the citric acid-metal extract by the bacterium Pseudomonas fluorescens for metals recovery. The ash contained the following metals: Al, As, Ba, Ca, Cd, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Se, Sr, Ti, and Zn. Optimization of the Citric Acid Process parameters which included citric acid molarity, contact time, the impact of mixing aggressiveness during extraction and pretreatment showed lead and cadmium removal from incinerator ash of >90%. Seeding the treated ash with P. fluorescens resulted in the removal of residual citric acid and biostabilization of any leachable lead, thus allowing it to pass EPA?s Toxicity Characteristic Leaching Procedure. Biodegradation of the citric acid extract removed >99% of the lead from the extract as well as other metals such as Al, Ca, Cu, Fe, Mg, Mn, Ti, and Zn. Speciation of the bioprecipitated lead by Extended X-ray Absorption Fine Structure at the National Synchrotron Light Source showed that the lead is predominantly associated with the phosphate and carboxyl functional groups in a stable form. Citric acid was completely recovered (>99%) from the extract by sulfide precipitation technique and the extraction efficiency of recovered citric acid is similar to that of the fresh citric acid. Recycling of the citric acid should result in considerable savings in the overall treatment cost. We have shown the potential application of this technology to remove and recover the metal contaminants from incinerator ash as well as from other heavy metal bearing wastes (i.e., electric arc furnace dust from steel industry) or soils. Information developed from this project is being applied to demonstrate the remediation of

  11. Citric Acid Passivation of Stainless Steel

    Science.gov (United States)

    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.

  12. Citraturic response to oral citric acid load

    Science.gov (United States)

    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.

  13. Citric Acid Alternative to Nitric Acid Passivation

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  15. CITRIC ACID PRODUCTION USING FERMENTATION TECHNOLOGY

    Directory of Open Access Journals (Sweden)

    ANKIT KUMAR

    2007-01-01

    Full Text Available Citric acid, C3H4OH(COOH3, (Scheele and Wehmer 1897 can be generally manufactured by chemical synthesis which is not much preferred now-a-days because of high costs involved in it and also by fermentation of sugar containing sources in the presence of fungus Aspergillus niger. Citric acid is used in confections and soft drinks ( as a flavouring agent, in metal-cleaning compositions, and in improving the stability of foods and other organic substances by suppressing the deleterious action of dissolved metal salts. Fermentation results in the breakdown of complex organic substances into simpler ones through the action of catalysis. This project involves the production of citric acid from fungal strain of Aspergillus niger ATCC 9142, using various sources like cane molasses, beet molasses, sweet potato and grape sugar by employing submerged and surface fermentation. The fermentation process has been carried out at ph 4.5 and temperature 28 0C. The recovery of citric acid from fermented broth is generally performed through three procedures-precipitation, extraction and adsorption(mainly using ion-exchange resins. The main aim of the project is to achieve a cost reduction in citric acid production by using less expensive substrates.

  16. 21 CFR 184.1033 - Citric acid.

    Science.gov (United States)

    2010-04-01

    ... compound 2-hydroxy-1,2,3-propanetricarboxylic acid. It is a naturally occurring constituent of plant and... 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...

  17. Solid state fermentation studies of citric acid production

    African Journals Online (AJOL)

    SERVER

    2008-03-04

    Mar 4, 2008 ... India. Accepted 27 November, 2007. Treated sugarcane bagasse supplemented with sucrose medium was found 1.7 fold (citric acid based ..... Academic Press. ... Relation between citric acid production and respiration rate of.

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

    Science.gov (United States)

    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.

  19. Crosslinking of agarose bioplastic using citric acid.

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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. Citric acid cycle intermediates in cardioprotection.

    Science.gov (United States)

    Czibik, Gabor; Steeples, Violetta; Yavari, Arash; Ashrafian, Houman

    2014-10-01

    Over the last decade, there has been a concerted clinical effort to deliver on the laboratory promise that a variety of maneuvers can profoundly increase cardiac tolerance to ischemia and/or reduce additional damage consequent upon reperfusion. Here we will review the proximity of the metabolic approach to clinical practice. Specifically, we will focus on how the citric acid cycle is involved in cardioprotection. Inspired by cross-fertilization between fundamental cancer biology and cardiovascular medicine, a set of metabolic observations have identified novel metabolic pathways, easily manipulable in man, which can harness metabolism to robustly combat ischemia-reperfusion injury. © 2014 American Heart Association, Inc.

  2. Thermodynamic properties of citric acid and the system citric acid-water

    NARCIS (Netherlands)

    Kruif, C.G. de; Miltenburg, J.C. van; Sprenkels, A.J.J.; Stevens, G.; Graaf, W. de; Wit, H.G.M. de

    1982-01-01

    The binary system citric acid-water has been investigated with static vapour pressure measurements, adiabatic calorimetry, solution calorimetry, solubility measurements and powder X-ray measurements. The data are correlated by thermodynamics and a large part of the phase diagram is given. Molar heat

  3. Thermodynamic properties of citric acid and the system citric acid-water

    NARCIS (Netherlands)

    Kruif, C.G. de; Miltenburg, J.C. van; Sprenkels, A.J.J.; Stevens, G.; Graaf, W. de; Wit, H.G.M. de

    1982-01-01

    The binary system citric acid-water has been investigated with static vapour pressure measurements, adiabatic calorimetry, solution calorimetry, solubility measurements and powder X-ray measurements. The data are correlated by thermodynamics and a large part of the phase diagram is given. Molar heat

  4. Heterogeneous uptake of amines by citric acid and humic acid.

    Science.gov (United States)

    Liu, Yongchun; Ma, Qingxin; He, Hong

    2012-10-16

    Heterogeneous uptake of methylamine (MA), dimethylamine (DMA), and trimethylamine (TMA) onto citric acid and humic acid was investigated using a Knudsen cell reactor coupled to a quadrupole mass spectrometer at 298 K. Acid-base reactions between amines and carboxylic acids were confirmed. The observed uptake coefficients of MA, DMA, and TMA on citric acid at 298 K were measured to be 7.31 ± 1.13 × 10(-3), 6.65 ± 0.49 × 10(-3), and 5.82 ± 0.68 × 10(-3), respectively, and showed independence of sample mass. The observed uptake coefficients of MA, DMA, and TMA on humic acid at 298 K increased linearly with sample mass, and the true uptake coefficients of MA, DMA, and TMA were measured to be 1.26 ± 0.07 × 10(-5), 7.33 ± 0.40 × 10(-6), and 4.75 ± 0.15 × 10(-6), respectively. Citric acid, having stronger acidity, showed a higher reactivity than humic acid for a given amine; while the steric effect of amines was found to govern the reactivity between amines and citric acid or humic acid.

  5. Effect of citric acid and citric acid-sucrose mixtures on swallowing in neurogenic oropharyngeal dysphagia.

    Science.gov (United States)

    Pelletier, Cathy A; Lawless, Harry T

    2003-01-01

    The ability of sour and sweet-sour mixtures to improve swallowing in 11 nursing home residents with neurogenic oropharyngeal dysphagia was investigated using fiberoptic endoscopic evaluation of swallowing. Citric acid (2.7%) significantly reduced aspiration and penetration compared with water. Teaspoon delivery of liquids significantly reduced aspiration and penetration compared with natural cup drinking. Subjects tended to appropriately self-regulate the cup volume they consumed after the first trial. A significant increase in spontaneous dry swallows was observed after both taste stimuli. The mechanisms for improved swallowing due to citric acid are not understood but may be due to increased gustatory and trigeminal stimulation of acid to the brainstem in neurologically impaired subjects.

  6. Effect of citric acid on noncovalent interactions in biopolymer jellies

    Directory of Open Access Journals (Sweden)

    Kuanyzhbek Musabekov

    2015-09-01

    Full Text Available The effect of citric acid on the formation of gels based on gelatine, melon pulp and sugar has been studied. It is found that the structuring of gelatin the presence of melon pulp is due to hydrogen bonds between the amino acids of gelatin and pectin melon by hydrogen bonds. It is shown that the structuring of gelatin and gelatin – melon pulp depends on the concentration of sugar. The addition of acid in the pectin-gelatin composition reduces the pH, the solubility of pectin and accelerates the formation of jelly. This is due to the fact that in the presence of citric acid reduced the degree of dissociation of galacturonic acid. The intensity of the effect of citric acid on the structure in the presence of melon pulp could be explained by the formation of hydrogen bonds between pectin and citric acid.

  7. Microbiological Production of Citric and Isocitric Acids from Sunflower Oil

    Directory of Open Access Journals (Sweden)

    Svetlana V. Kamzolova

    2008-01-01

    Full Text Available The growth of wild type strain Yarrowia lipolytica VKM Y-2373 and its mutant Yarrowia lipolytica N 15 as well the biosynthesis of citric and isocitric acids on sunflower oil were studied. It was indicated that cell growth was associated with the simultaneous utilization of glycerol and free fatty acids produced during oil hydrolysis. The activities of enzymes of glycerol metabolism (glycerol kinase, fatty acid assimilation enzymes of glyoxylate cycle (isocitrate lyase and malate synthase and citric acid cycle were comparatively assayed in Y. lipolytica grown on sunflower oil, glycerol and oleic acid. Glycerol kinase and enzymes of glyoxylate cycle were active during the whole period of cell cultivation on sunflower oil. Citric acid production and a ratio between citric and isocitric acids depended on both the strain used and the medium composition. It was revealed that wild type strain Y. lipolytica VKM Y-2373 produced almost equal amounts of citric and isocitric acids at pH=4.5 and predominantly accumulated isocitric acid at pH=6.0. The mutant Y. lipolytica N 15 produced only citric acid (150 g/L with mass yield (YCA of 1.32 g/g. Biochemical characteristics of mutant strain Y. lipolytica N 15 were discussed.

  8. Effects of citric acid on separation of sillimanite from quartz

    Institute of Scientific and Technical Information of China (English)

    李晔; 雷东升; 鲁巍; 许时

    2002-01-01

    Quartz is the main gangue mineral of sillimanite. The results show that Al3+ and Fe3+ ion can activate the floatation of quartz and make the separation of quartz and sillimanite difficult when anion collector is used, and citric acid can inhibit the quartz activated by metallic ion and have slight influence on the sillimanite. X-ray photoelectronic energy spectrum analysis indicates that there are obvious electronic energy peaks on the surface of the quartz before citric acid is added into the ore pulp in presence of Al3+ and Fe3+, and after citric acid is added, the energy peak vanished. So citric acid can make Al3+ and Fe3+ on the surface of quartz solve and decrease the active points on the surface of quartz which can adsorb anion collector.

  9. Biothermoplastics from hydrolyzed and citric acid crosslinked chicken feathers.

    Science.gov (United States)

    Reddy, Narendra; Chen, Lihong; Yang, Yiqi

    2013-04-01

    We demonstrate a novel approach of developing thermoplastic films from feathers by alkaline hydrolysis and crosslinking with citric acid. Unlike previous approaches that used toxic chemicals, complicated and/or expensive methods to develop films, in this research, feathers were hydrolyzed using various concentrations of alkali and the hydrolyzed feathers were compression molded into films using glycerol as plasticizer and crosslinked with citric acid to improve water stability. Alkali hydrolyzed feathers could be compression molded into films with tensile strength of 5.9 MPa and elongation of 31.7% but had poor wet strength. Feather films crosslinked with citric acid had tensile strength of 1.9 MPa and elongation of 24.6% after being in 90% humidity at 21 °C for 24 hours. Alkaline hydrolysis and citric acid crosslinking provides an opportunity to develop inexpensive and biodegradable thermoplastics from the inexpensive, renewable and sustainable poultry feathers.

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

    Science.gov (United States)

    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 ...

  11. Psychophysical assessments of sourness in citric acid-ethanol mixtures.

    Science.gov (United States)

    Guirao, Miguelina; Greco Driano, Ezequiel J; Evin, Diego; Calviño, Amalia

    2013-12-01

    The effect of ethanol in modulating the intensity and duration of the perceived sourness induced by citric acid was studied. Magnitude Estimation-Converging Limits method was applied to rate the sourness of seven solutions (3-70 mM) of citric acid in aqueous solution presented alone and mixed with 8% V/V or 15% V/V ethanol. Dynamic sourness ratings of 5, 15, and 45 mM citric acid alone and mixed with the same two ethanol levels were assessed by the Time Intensity Method (TI). Results were consistent with both methods. Sourness changed with citric acid concentration and ethanol levels. From TI measurements, a similar interactive pattern was obtained for parameters as duration, area under the curve, peak and average intensity.

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

    Science.gov (United States)

    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.

  13. 78 FR 34338 - Citric Acid and Certain Citrate Salts From Canada: Preliminary Results of Antidumping Duty...

    Science.gov (United States)

    2013-06-07

    ...: Antidumping Duty Orders, 74 FR 25703 (May 29, 2009) (Citric Acid Duty Orders). Methodology The Department has... International Trade Administration Citric Acid and Certain Citrate Salts From Canada: Preliminary Results of... administrative review of the antidumping duty order on citric acid and certain citrate salts (citric acid)......

  14. 21 CFR 173.280 - Solvent extraction process for citric acid.

    Science.gov (United States)

    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...

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

    Science.gov (United States)

    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.

  16. Production of Citric Acid from Apple Pomace Enzymolyzed by Cellulase

    Institute of Scientific and Technical Information of China (English)

    宋纪蓉; 黄洁; 徐抗震; 赵巧云

    2003-01-01

    Cellulase can evidently increase the content of glucose and has a significant effect on the production of citric acid from apple pomace by Aspergillus niger. Based on experiments, a cellulolytic enzyme named cellulase A6 was found able to produce about 170 g glucose from 1 kg dried apple pomace after 12 h reaction, with cellulase concentration of 20 U/g in the medium at 50℃, natural pH without pretreatment of alkali. Using the treated apple pomace as a liquid state substrate, Aspergillus niger-C selected out was able to produce about 256 g citric acid from 1 kg dried apple pomace at 35℃ in 3 d or 30℃ in 5 d with flask rotation speed of 210 r/min, and the conversion of citric acid could reach 80% based on the amount of sugar consumed.

  17. Synthesis of zincosilicate mordenite using citric acid as complexing agent

    Institute of Scientific and Technical Information of China (English)

    MeiDong; JianjuoWang; YuhanSun

    2001-01-01

    The zincosilicate analog of zeolite mordenite was hydrothermally synthesized in the presence of citric acid and characterized with several spectroscopic techniques.The zeolite thus prepared had a higher crystallinity and Zn concentration in the framework compared with the one obtained in the absence of citric acid.XRD and FTIR provided evidence for the incorporation of Zn in the framework.Results of XAFS indicated a tetrahedral structure of Zn in the lattice framework with a Zn-O distancd of 0.1938nm.It is speculated that the citric acid might decrease the concentration of Zn2 in the synthesis mixture,there by preventing the unfavorable-formation of oxide or hydroxide species.2001 Elsevier Science B.V.All rights reserved.

  18. Effect of mineral supplements to citric acid on enamel erosion.

    Science.gov (United States)

    Attin, T; Meyer, K; Hellwig, E; Buchalla, W; Lennon, A M

    2003-11-01

    The aim of this study was to evaluate the effect of mineral supplements to citric acid (1%; pH 2.21) on enamel erosion under controlled conditions in an artificial mouth. From each of 156 bovine incisors one polished enamel sample was prepared. The samples were divided among 13 experimental groups (n=12). In group 1 citric acid only was used (control). In groups 2-10 either calcium, phosphate or fluoride in various low concentrations was admixed to the citric acid. In groups 11-13 the citric acid was supplemented with a mixture of calcium, phosphate and fluoride. For demineralisation the specimens were rinsed with the respective solution for 1 min, immediately followed by a remineralisation period with artificial saliva (1 min). The specimens were cycled through this alternating procedure five times followed by rinsing for 8 h with artificial saliva. The de- and remineralisation cycle was repeated three times for each specimen interrupted by the 8 h-remineralisation periods. Before and after the experiments, the specimens were examined using microhardness testing (Knoop hardness) and laser profilometry. Hardness loss and enamel dissolution was significantly higher for the controls as compared to the remaining groups. Significantly lowest hardness loss for all groups was recorded for group 12 with admixture of calcium, phosphate and fluoride to citric acid. The significantly highest enamel loss was recorded for the controls compared to all other samples. Groups 3 and 4 revealed significantly lower and higher tissue loss compared to the remaining groups (2-13), respectively. The other groups did not differ significantly from each other. Modification of citric acid with calcium, phosphate and fluoride exerts a significant protective potential with respect to dental erosion. However, with the low concentrations applied enamel dissolution could not be completely prevented.

  19. Production of Citric Acid by Aspergillus niger Using Pineapple Waste

    OpenAIRE

    S. O. Kareem; Akpan, I.; Alebiowu, O. O.

    2010-01-01

    A solid state fermentation was developed for citric acid production from pineapple waste by Aspergillus niger KS-7. The medium was supplemented with different concentration of glucose, sucrose, ammonium nitrate and ammonium phosphate. It was found that pineapple waste with 15% (w/v) sucrose and ammonium nitrate (0.25% w/v) gave the optimum citric acid secretion (60.61 g/kg) in the presence of methanol (2% v/v) when fermented for 5 days at 30 °C with the initial moisture content of 65%. The ...

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

    Science.gov (United States)

    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.

  1. Microbiological Production of Citric and Isocitric Acids from Sunflower Oil

    OpenAIRE

    Svetlana V. Kamzolova; Finogenova, Tatiana V; Igor G. Morgunov

    2008-01-01

    The growth of wild type strain Yarrowia lipolytica VKM Y-2373 and its mutant Yarrowia lipolytica N 15 as well the biosynthesis of citric and isocitric acids on sunflower oil were studied. It was indicated that cell growth was associated with the simultaneous utilization of glycerol and free fatty acids produced during oil hydrolysis. The activities of enzymes of glycerol metabolism (glycerol kinase), fatty acid assimilation enzymes of glyoxylate cycle (isocitrate lyase and malate synthase) an...

  2. Development of pectin films with pomegranate juice and citric acid.

    Science.gov (United States)

    Azeredo, Henriette M C; Morrugares-Carmona, Rosario; Wellner, Nikolaus; Cross, Kathryn; Bajka, Balazs; Waldron, Keith W

    2016-05-01

    The influence of pomegranate juice (PJ, replacing water as solvent) and citric acid (CA) on properties of pectin films was studied. PJ provided the films with a bright red color, and acted as a plasticizer. Increasing PJ/water ratio from 0/100 to 100/0 resulted in enhanced elongation (from 2% to 20%), decreased strength (from 10 to anthocyanins.

  3. Studies of citric acid metabolism in heart muscle

    NARCIS (Netherlands)

    Meduski, J.W.

    1950-01-01

    1. The pentabromoacetone method for the determination of citric acid was studied; a modification of the procedure of Natelson, Lugovoy and Pincus was used. 2. Two tissue preparations were obtained. The first by washing with water, the second by washing with water and then with 0.5% sodium

  4. Studies of citric acid metabolism in heart muscle

    NARCIS (Netherlands)

    Meduski, J.W.

    1950-01-01

    1. The pentabromoacetone method for the determination of citric acid was studied; a modification of the procedure of Natelson, Lugovoy and Pincus was used. 2. Two tissue preparations were obtained. The first by washing with water, the second by washing with water and then with 0.5% sodium bicarbo

  5. Citric acid cycle biomimic on a carbon electrode.

    Science.gov (United States)

    Sokic-Lazic, Daria; Minteer, Shelley D

    2008-12-01

    The citric acid cycle is one of the main metabolic pathways living cells utilize to completely oxidize biofuels to carbon dioxide and water. The overall goal of this research is to mimic the citric acid cycle at the carbon surface of an electrode in order to achieve complete oxidation of ethanol at a bioanode to increase biofuel cell energy density. In order to mimic this process, dehydrogenase enzymes (known to be the electron or energy producing enzymes of the citric acid cycle) are immobilized in cascades at an electrode surface along with non-energy producing enzymes necessary for the cycle to progress. Six enzymatic schemes were investigated each containing an additional dehydrogenase enzyme involved in the complete oxidation of ethanol. An increase in current density is observed along with an increase in power density with each additional dehydrogenase immobilized on an electrode, reflecting increased electron production at the bioanode with deeper oxidation of the ethanol biofuel. By mimicking the complete citric acid cycle on a carbon electrode, power density was increased 8.71-fold compared to a single enzyme (alcohol dehydrogenase)-based ethanol/air biofuel cell.

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

    Science.gov (United States)

    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.

  7. 78 FR 34648 - Citric Acid and Certain Citrate Salts: Preliminary Results of Countervailing Duty Administrative...

    Science.gov (United States)

    2013-06-10

    ... International Trade Administration Citric Acid and Certain Citrate Salts: Preliminary Results of Countervailing... review of the countervailing duty (CVD) order on citric acid and citrate salts from the People's Republic... (202) 482-1503. Scope of the Order The merchandise subject to the order is citric acid and...

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

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 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...

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

    Science.gov (United States)

    2013-10-30

    ... China: Antidumping Duty Orders, 74 FR 25703 (May 29, 2009) (Citric Acid Duty Orders). Period of Review...-others rate made effective by the LTFV investigation. See Citric Acid Duty Orders, 74 FR 25703. These... International Trade Administration Citric Acid and Certain Citrate Salts From Canada: Final Results...

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

    Science.gov (United States)

    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.

  11. Citric acid cycle and role of its intermediates in metabolism.

    Science.gov (United States)

    Akram, Muhammad

    2014-04-01

    The citric acid cycle is the final common oxidative pathway for carbohydrates, fats and amino acids. It is the most important metabolic pathway for the energy supply to the body. TCA is the most important central pathway connecting almost all the individual metabolic pathways. In this review article, introduction, regulation and energetics of TCA cycle have been discussed. The present study was carried out to review literature on TCA cycle.

  12. Hydrophobic starch nanocrystals preparations through crosslinking modification using citric acid.

    Science.gov (United States)

    Zhou, Jiang; Tong, Jin; Su, Xingguang; Ren, Lili

    2016-10-01

    Biodegradable starch nanocrystals prepared by an acid treatment process were modified through crosslinking modification using citric acid as reactant by a dry reaction method. The occurrence of crosslinking modification was evaluated by Fourier transform infrared spectroscopy and swelling degree. X-ray diffraction, wettability tests and contact angle measurements were used to characterize the modified starch nanocrystals. It was found that the crosslinked starch nanocrystals displayed a higher affinity for low polar solvents such as dichloromethane. The surface of starch nanocrystals became more roughness after crosslinking modification with citric acid and the size decreased as revealed by scanning electron microscopy and dynamic light scattering results. XRD analysis showed that the crystalline structure of starch nanocrystals was basically not changed after the crosslinking modification with shorter heating time. The resulting hydrophobic starch nanocrystals are versatile precursors to the development of nanocomposites.

  13. Interaction of Cd and citric acid, EDTA in red soil

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Adsorption and desorption process of cadmium in redsoil(Ferrisols) as well as the influence by media's pH were investigated in detail with and without citric acid and EDTA. Experimental results clearly showed that Cd adsorption in red soil was affected significantly by the coexisted organic chemicals. In the presence of citric acid and EDTA, Cd adsorption in red soil increased with pH in acid media but decreased in high pH one. Further studies placed stress on the adsorbed Cd in red soil which was found to be existed mainly as exchangeable one at pH<5.5, and desorption rate by 0.10 mol/L NaNO3 gave a peak-shaped curve due to the difference of specifically and nonspecifically adsorbed Cd with pH's change.

  14. Citric acid cycle and the origin of MARS.

    Science.gov (United States)

    Eswarappa, Sandeepa M; Fox, Paul L

    2013-05-01

    The vertebrate multiaminoacyl tRNA synthetase complex (MARS) is an assemblage of nine aminoacyl tRNA synthetases (ARSs) and three non-synthetase scaffold proteins, aminoacyl tRNA synthetase complex-interacting multifunctional protein (AIMP)1, AIMP2, and AIMP3. The evolutionary origin of the MARS is unclear, as is the significance of the inclusion of only nine of 20 tRNA synthetases. Eight of the nine amino acids corresponding to ARSs of the MARS are derived from two citric acid cycle intermediates, α-ketoglutatrate and oxaloacetate. We propose that the metabolic link with the citric acid cycle, the appearance of scaffolding proteins AIMP2 and AIMP3, and the subsequent disappearance of the glyoxylate cycle, together facilitated the origin of the MARS in a common ancestor of metazoans and choanoflagellates. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Electrochemical monitoring of citric acid production by Aspergillus niger

    Energy Technology Data Exchange (ETDEWEB)

    Kutyła-Olesiuk, Anna; Wawrzyniak, Urszula E.; Ciosek, Patrycja; Wróblewski, Wojciech, E-mail: wuwu@ch.pw.edu.pl

    2014-05-01

    Highlights: • Citric acid fermentation process (production) by Aspergillus niger. • Qualitative/quantitative monitoring of standard culture and culture infected with yeast. • Electronic tongue based on potentiometric and voltammetric sensors. • Evaluation of the progress and the correctness of the fermentation process. • The highest classification abilities of the hybrid electronic tongue. - Abstract: Hybrid electronic tongue was developed for the monitoring of citric acid production by Aspergillus niger. The system based on various potentiometric/voltammetric sensors and appropriate chemometric techniques provided correct qualitative and quantitative classification of the samples collected during standard Aspergillus niger culture and culture infected with yeast. The performance of the proposed approach was compared with the monitoring of the fermentation process carried out using classical methods. The results obtained proved, that the designed hybrid electronic tongue was able to evaluate the progress and correctness of the fermentation process.

  16. Patterns of diversity of citric acid cycle enzymes.

    Science.gov (United States)

    Weitzman, P D

    1987-01-01

    The citric acid cycle performs a dual role in cell metabolism, acting as a source of both 'energy' and biosynthetic starting materials. The widespread occurrence of the cycle throughout Nature is an excellent example of the unity of biochemistry, but closer examination reveals that there is considerable diversity in the citric acid cycle of different organisms with respect to metabolic role, molecular enzymology and mode of regulation. Two enzymes of the cycle--citrate synthase and succinate thiokinase--have been found to exhibit particularly striking patterns of diversity in structure and catalytic and regulatory function. Some of these patterns show a correlation with the taxonomic groupings of the organisms and with their physiological characteristics. Comparative enzyme studies have a contribution to make to an ultimate understanding of the cycle and its cellular operation, and there are substantial benefits to be gained from interactive studies on both prokaryotic and eukaryotic systems.

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

    Science.gov (United States)

    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· mgCODre(-1) (0.22 ± 0.09 mgTSS mgNre(-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%).

  18. 76 FR 17835 - Citric Acid and Certain Citrate Salts From the People's Republic of China: Extension of Time...

    Science.gov (United States)

    2011-03-31

    ... International Trade Administration A-570-937] Citric Acid and Certain Citrate Salts From the People's Republic... order on citric acid and certain citrate salts (``citric acid'') from the People's Republic of China.... See Citric Acid and Certain Citrate Salts from the People's Republic of China: Notice of Extension...

  19. 76 FR 4288 - Citric Acid and Certain Citrate Salts From the People's Republic of China: Notice of Extension of...

    Science.gov (United States)

    2011-01-25

    ... International Trade Administration Citric Acid and Certain Citrate Salts From the People's Republic of China... review of the antidumping duty order on citric acid and certain citrate salts (``citric acid'') from the... administrative review of citric acid from the PRC within this time limit. Among other things, additional time...

  20. 77 FR 9891 - Citric Acid and Certain Citrate Salts from the People's Republic of China: Amended Final Results...

    Science.gov (United States)

    2012-02-21

    ... International Trade Administration Citric Acid and Certain Citrate Salts from the People's Republic of China... antidumping duty order on citric acid and certain citrate salts (``citric acid'') from the People's Republic... Act of 1930, as amended (``the Act''). \\1\\ See Citric Acid and Certain Citrate Salts from the...

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

    Science.gov (United States)

    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 %.

  2. Citric acid cycle and the origin of MARS

    OpenAIRE

    Eswarappa, Sandeepa M.; Fox, Paul L

    2013-01-01

    The vertebrate multi-aminoacyl tRNA synthetase complex (MARS) is an assemblage of nine aminoacyl tRNA synthetases (ARSs) and three non-synthetase scaffold proteins, AIMP1 (aminoacyl tRNA synthetase complex-interacting multifunctional protein-1), AIMP2, and AIMP3. The evolutionary origin of the MARS is unclear, as is the significance of the inclusion of only nine of twenty tRNA synthetases. Eight of the nine amino acids corresponding to ARSs of the MARS are derived from two citric acid cycle i...

  3. Citric acid cycle and the origin of MARS

    OpenAIRE

    Sandeepa M Eswarappa; Paul L Fox

    2013-01-01

    The vertebrate multi-aminoacyl tRNA synthetase complex (MARS) is an assemblage of nine aminoacyl tRNA synthetases (ARSs) and three non-synthetase scaffold proteins, AIMP1 (aminoacyl tRNA synthetase complex-interacting multifunctional protein-1), AIMP2, and AIMP3. The evolutionary origin of the MARS is unclear, as is the significance of the inclusion of only nine of twenty tRNA synthetases. Eight of the nine amino acids corresponding to ARSs of the MARS are derived from two citric acid cycle i...

  4. 76 FR 49735 - Citric Acid and Certain Citrate Salts From the People's Republic of China: Partial Rescission of...

    Science.gov (United States)

    2011-08-11

    ... International Trade Administration Citric Acid and Certain Citrate Salts From the People's Republic of China... review of the countervailing duty order on citric acid and certain citrate salts (``citric acid'') from..., 2011, Huangshi Xinghua Biochemical Co., Ltd. (``Xinghua''), a producer and exporter of citric...

  5. Synthesis of New Functionalized Citric Acid-based Dendrimers as Nanocarrier Agents for Drug Delivery

    Directory of Open Access Journals (Sweden)

    Sanaz Motamedi

    2011-06-01

    Full Text Available Introduction: Citric acid-polyethylene glycol-citric acid (CPEGC triblock dendrimers can serve as potential delivery systems. Methods: In this investigation, CPEGC triblock dendrimers were synthesized and then imidazole groups were conjugated onto the surface of the G1, G2 and G3 of the obtained dendrimers. In order to study the type of the interactions between the functionalized dendrimers and a drug molecule, Naproxen which contains acidic groups, was examined as a hydrophobic drug in which the interactions would be of the electrostatic kind between its acidic groups and the lone pair electrons of nitrogen atom in imidazole groups. The quantity of the trapped drug and also the amount of its release were measured with UV spectrometric method in pH 1, 7.4 and 10. The average diameter of the nanocarriers was measured by Dynamic Light Scattering (DLS technique Results: The size range of particles was determined to be 16-50 nm for different generations. The rate of the release increased in pH=10 in all generations due to the increase in Naproxen solubility and the hydrolysis of the esteric bonds in the mentioned pH. The results showed that the amount of the trapped drug increased with the increase in the generation of the dendrimer and pH. Conclusion: Based on our findings, we suggest CPEGC triblock dendrimers possess great potential to be used as drug/gene delivery system.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

  8. Electrochemical monitoring of citric acid production by Aspergillus niger.

    Science.gov (United States)

    Kutyła-Olesiuk, Anna; Wawrzyniak, Urszula E; Ciosek, Patrycja; Wróblewski, Wojciech

    2014-05-01

    Hybrid electronic tongue was developed for the monitoring of citric acid production by Aspergillus niger. The system based on various potentiometric/voltammetric sensors and appropriate chemometric techniques provided correct qualitative and quantitative classification of the samples collected during standard Aspergillus niger culture and culture infected with yeast. The performance of the proposed approach was compared with the monitoring of the fermentation process carried out using classical methods. The results obtained proved, that the designed hybrid electronic tongue was able to evaluate the progress and correctness of the fermentation process.

  9. Pectin extraction from pomegranate peels with citric acid.

    Science.gov (United States)

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

    2016-07-01

    Pectins were extracted from pomegranate peels with citric acid, according to a central composite design with three variables: pH (2-4), temperature (70-90°C), and extraction time (40-150min). Fourier transform infrared (FTIR) spectroscopy was used to follow changes in material composition during the main steps of pectin extraction, and also to determine the degree of methyl esterification and galacturonic acid content of pectins produced under different conditions. Harsh conditions enhanced the extraction yield and the galacturonic acid contents, but decreased the degree of methoxylation. The optimum extraction conditions, defined as those predicted to result in a yield of galacturonic acid higher than 8g/100g while keeping a minimum degree of methoxylation of 54% were: 88°C, 120min, pH 2.5. Close agreement was found between experimental and predicted values at the extraction conditions defined as optimum.

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

    Science.gov (United States)

    Auta, Helen Shnada; 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.

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

    OpenAIRE

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

    2015-01-01

    Background 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 s...

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

    Science.gov (United States)

    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.

  13. Fumaric acid esters in dermatology

    Directory of Open Access Journals (Sweden)

    Uwe Wollina

    2011-01-01

    Full Text Available Fumaric acid esters (FAE are substances of interest in dermatology. FAE exert various activities on cutaneous cells and cytokine networks. So far only a mixture of dimethylfumarate (DMF and three salts of monoethylfumarate (MEF have gained approval for the oral treatment of moderate-to-severe plaque-type psoriasis in Germany. DMF seems to be the major active component. There is evidence that FAE are not only effective and safe in psoriasis but granulomatous non-infectious diseases like granuloma annulare, necrobiosis lipoidica and sarcoidosis. In vitro and animal studies suggest some activity in malignant melanoma as well.

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

    Science.gov (United States)

    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.

  15. Aqueous citric acid as a promising cleaning agent of whey evaporators

    DEFF Research Database (Denmark)

    Hedegaard, Martina Vavrusova; P. Johansen, Nikolaj; Garcia, André Castilho

    2017-01-01

    Scale in evaporators for lactose production was identified as mainly calcium citrate tetrahydrate with phosphate contaminations. Dissolution of 3.00 g of scale in aqueous solutions of 0.100, 0.500, and 1.00 mol L−1 citric acid with final volumes of 100, 50, and 25 mL was investigated. The highest...... concentration of citric acid was the most effective for all the investigated volumes. From the citric acid solutions, spontaneously supersaturated in calcium citrate tetrahydrate during scale dissolution in the smaller volumes for all citric acid concentrations, calcium citrate tetrahydrate slowly precipitated...... in acceptable purity for technical use. Dissolution efficiency of aqueous solutions of 0.200 mol L−1 nitric acid combined with 0.100, 0.500, and 1.00 mol L−1 citric acid with final volumes of 100, 50, and 25 mL showed synergistic effect especially for the higher concentrations and lower volumes of two acids...

  16. [Extraction of heavy metals from sewage sludge using aspartic acid and citric acid].

    Science.gov (United States)

    Zhang, Hua; Zhu, Zhi-Liang; Zhang, Li-Hua; Qiu, Yan-Ling; Zhao, Jian-Fu

    2008-03-01

    Aspartic acid, as a biodegradable natural amino acid, was used to separate and remove the heavy metals from the sewage sludge based on chemical extraction technology. Under various conditions, the extraction processes were carried out for the sewage sludge from Shanghai Taopu Municipal Wastewater Plant. The comparison of extraction between aspartic acid and citric acid was also discussed for the separation of three heavy metals from sewage sludge. The results showed that pH and the dosage of aspartic acid or citric acid had a significant effect on the extraction efficiency. Zn, Ni and Cu can be apart extracted for more than 85% by aspartic acid at low pH. With the increment of pH value, the extraction ration decreased gradually for both two systems. Within the whole pH range, aspartic acid showed higher extraction efficiency for Ni, Cu than citric acid and the extraction efficiencies of aspartic acid for Ni, Cu were found to respectively be more than 50%, 40%. For the situation of Zn, citric acid had a higher extraction efficiency at pH > or = 3.0.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    2012-01-10

    ... International Trade Administration Citric Acid and Certain Citrate Salts From the People's Republic of China... acid and certain citrate salts (``citric acid'') from the People's Republic of China (``PRC''). See... of the administrative review of citric acid from the PRC within this time limit....

  19. Quantitative determination of citric acid in seminal plasma by using Raman spectroscopy.

    Science.gov (United States)

    Huang, Zufang; Chen, Xiwen; Li, Yongzeng; Chen, Jinhua; Lin, Juqiang; Wang, Jing; Lei, Jinping; Chen, Rong

    2013-07-01

    In this study, Raman spectroscopy was first used to study the linear relationship between Raman spectral intensities and citric acid concentrations in aqueous solution. By using the specific Raman band of 942 cm(-1), concentrations of citric acid ranging from 2 to 20 mg/mL were observed linearly (R(2) = 0.993), and the limit of detection was 1.0 mg/mL. Then, citric acid detection in clinical seminal plasma ultrafiltrate samples was performed, and the intensity of the Raman-specific peak demonstrates a good linear correlation (R(2) = 0.946) with citric acid concentrations determined by the enzymatic method. Our results showed that Raman spectroscopy has the potential of being applied to detect concentrations of citric acid in seminal plasma in clinic.

  20. Synthesis and Application of a Novel Perfluorooctylated Citric Acid

    Institute of Scientific and Technical Information of China (English)

    YANG Wei; QING Feng-Ling; MENG Wei-Dong

    2005-01-01

    A novel perfluorooctylated citric acid was synthesized successfully via allylation of triethyl citrate followed by perfluorooctylation, reduction and hydrolysis. The fabrics treated with this compound showed good oil repellent and moderate water repellent properties: the oil repellent rating and the water repellent score were 6 and 80 respectively.Even after 10 washing cycles, the repellent properties were kept at the same level. The finished fabrics also showed some wrinkle-resistant properties, and the dry wrinkle recovery angle was increased by 53° compared with untreated fabrics. The critical surface energy of the treated fabric surface was 20±1 mN/m. This multifunctional compound also showed good water solubility, which would be beneficial for the environmental protection.

  1. Citric acid assisted phytoremediation of cadmium by Brassica napus L.

    Science.gov (United States)

    Ehsan, Sana; Ali, Shafaqat; Noureen, Shamaila; Mahmood, Khalid; Farid, Mujahid; Ishaque, Wajid; Shakoor, Muhammad Bilal; Rizwan, Muhammad

    2014-08-01

    Phytoextraction is an eco-friendly and cost-effective technique for removal of toxins, especially heavy metals and metalloids from contaminated soils by the roots of high biomass producing plant species with subsequent transport to aerial parts. Lower metal bioavailability often limits the phytoextraction. Organic chelators can help to improve this biological technique by increasing metal solubility. The aim of the present study was to investigate the possibility of improving the phytoextraction of Cd by the application of citric acid. For this purpose, plants were grown in hydroponics under controlled conditions. Results indicated that Cd supply significantly decreased the plant growth, biomass, pigments, photosynthetic characteristics and protein contents which were accompanied by a significant increase in Cd concentration, hydrogen peroxide (H₂O₂), electrolyte leakage, malondialdehyde (MDA) accumulation and decrease in antioxidant capacity. The effects were dose dependent with obvious effects at higher Cd concentration. Application of CA significantly enhanced Cd uptake and its accumulation in plant roots, stems and leaves. Citric acid alleviated Cd toxicity by increasing plant biomass and photosynthetic and growth parameters alone and in combination with Cd and by reducing oxidative stress as observed by reduction in MDA and H₂O₂ production and decreased electrolyte leakage induced by Cd stress. Application of CA also enhanced the antioxidant enzymes activity alone and under Cd stress. Thus, the data indicate that exogenous CA application can increase Cd uptake and minimize Cd stress in plants and may be beneficial in accelerating the phytoextraction of Cd through hyper-accumulating plants such as Brassica napus L.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  4. 76 FR 47146 - Citric Acid and Certain Citrate Salts From the People's Republic of China: Extension of Time...

    Science.gov (United States)

    2011-08-04

    ... International Trade Administration Citric Acid and Certain Citrate Salts From the People's Republic of China...'') 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...

  5. 75 FR 71078 - Citric Acid and Certain Citrate Salts From People's Republic of China: Partial Rescission of...

    Science.gov (United States)

    2010-11-22

    ... International Trade Administration Citric Acid and Certain Citrate Salts From People's Republic of China...: Countervailing Duty Administrative Review--Citric Acid and Certain Citrate Salts (August 17, 2010). Partial... Biochemical Co., Ltd. Hunan Dongting Citric Acid Chemicals Co., Ltd. Hunan Yinhai Petrochemicals Group...

  6. 76 FR 56158 - Citric Acid and Certain Citrate Salts From the People's Republic of China: Extension of Time...

    Science.gov (United States)

    2011-09-12

    ... International Trade Administration Citric Acid and Certain Citrate Salts From the People's Republic of China... administrative review of the countervailing duty order on citric acid and certain citrate sales from People's Republic of China, covering the period September 19, 2008, through December 31, 2009. See Citric Acid...

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  9. Eco-friendly Rot and Crease Resistance Finishing of Jute Fabric using Citric Acid and Chitosan

    Science.gov (United States)

    Samanta, A. K.; Bagchi, A.

    2013-03-01

    Citric acid (CA) along with chitosan was used on bleached jute fabrics to impart anti crease and rot resistance properties in one step. The treatment was carried out by pad-dry-cure method in presence of sodium hypophosphite monohydrate catalyst. Curing at 150° Centigrade for 5 min delivered good crease resistant property (dry crease recovery angle is 244°) and high rot resistance simultaneously by a single treatment, which are durable for five washings with distilled water. Strength retention of jute fabric after 21 days soil burial was found to be 81 % and the loss (%) in strength due to this treatment was 15-18 %. The results showed that chitosan and CA treated-fabric exhibited higher rot resistance (as indicated by soil burial test) when compared to either CA or chitosan by individual treatment. The effect of CA and chitosan combination on the resistance to rotting of jute fabric was found to be synergistic which is higher than the sum of the effects of individual chemicals. CA possibly reacts with hydroxyl groups in cellulose or chitosan to form ester. The CA and chitosan finished fabric has adverse effect on stiffness. Thermal studies showed that final residue left at 500° C was much higher for CA and chitosan treated fabric than untreated jute fabric. FTIR spectroscopy suggested the formation of ester cross-linkage between the jute fibre, CA and chitosan and hence it is understood that this rot resistant finish on jute fabric become durable by this mechanism.

  10. Conversion of carbohydrates to levulinic acid esters

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention relates to the field of converting carbohydrates into levulinic acid, a platform chemical for many chemical end products. More specifically the invention relates to a method for converting carbohydrates such as mono-, di- or polysaccharides, obtained from for example biomass...... production into a suitable levulinic acid ester in the presence of a zeolite or zeotype catalyst and a suitable alcohol, and the ester may be further converted into levulinic acid if desired....

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

    Science.gov (United States)

    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.

  12. Preparation of Citric Acid Crosslinked Chitosan/Poly(Vinyl Alcohol Blend Membranes for Creatinine Transport

    Directory of Open Access Journals (Sweden)

    Retno Ariadi Lusiana

    2016-08-01

    Full Text Available Preparation of membrane using crosslinking reaction between chitosan and citric acid showed that functional group modification increased the number of active carrier groups which lead to better transport capacity of the membrane. In addition, the substitution of the carboxyl group increased creatinine permeation of chitosan membrane. The transport capacity of citric acid crosslinked chitosan membrane for creatinine was found to be 6.3 mg/L. The presence of cyanocobalamin slightly hindered the transport of creatinine although compounds did not able to pass through citric acid crosslinked chitosan/poly(vinyl alcohol blend membrane, as compounds no found in the acceptor phase.

  13. Effects of Citric Acid Concentration and Activation Temperature on the Synthesis of Carbon Nanotubes

    Institute of Scientific and Technical Information of China (English)

    Fengyi Li; Minwei Wang; Rongbin Zhang; Renzhong Wei; Niancai Peng

    2004-01-01

    A series of Ni-La-Mg catalyst samples were prepared by citric acid complex method, and carbon nanotubes were synthesized by catalytic decomposition of CH4 on these catalysts. The effects of the citric acid concentration and the activation temperature on catalytic activity were investigated by CO adsorption,TEM and XRD techniques. The experimental results showed that the particle size of the catalysts prepared through gel auto-combustion varied with the concentration of citric acid. Therefore carbon nanotubes with different diameters were obtained correspondingly. The effect of activation temperature on the activity of catalyst was negligible from 500 to 700 ℃, but it became pronounced at lower or higher temperatures.

  14. EXTRACTION OF CITRIC ACID FROM FERMENTATION BROTH USING ION—EXCHANGE METHOD

    Institute of Scientific and Technical Information of China (English)

    LiuZuozhen; WangXiangyang; 等

    1998-01-01

    A number of ion-exchange resins were tested on their capacity to adsorb citric acid,among them resin 335,d315, Amberlite IRA-35 and IRA-68 exhibited higher adsorption capacity.We chose resin 335 and D315 to be used for extraction of citric acid from fermentation broth,followed by elution with 10% ammonia liquor,decoloration with K-15 carbon and removal of ammonia with resin 732,converting citrate of free citric acid with a concentration of 10% and an amount of readily carbonizable substance meeting the GB 8269-87 standard.

  15. Citric Acid Cycle Metabolites Predict the Severity of Myocardial Stunning and Mortality in Newborn Pigs

    DEFF Research Database (Denmark)

    Hyldebrandt, Janus Adler; Støttrup, Nicolaj Brejnholt; Frederiksen, Christian Alcaraz

    2016-01-01

    , which so far are undetermined. DESIGN: A total of 28 newborn pigs were instrumented with a microdialysis catheter in the right ventricle, and intercellular citric acid cycle intermediates and adenosine metabolite concentrations were determined at 20-minute intervals. Stunning was induced by 10 cycles...... animals (n = 8), concentrations of succinate (p citric acid cycle intermediates and adenosine metabolites reflects...... the presence of myocardial stunning and predicts mortality in acute noninfarct right ventricular heart failure in newborn pigs. This phenomenon occurs independently of the type of inotrope, suggesting that citric acid cycle intermediates represent potential markers of acute noninfarct heart failure....

  16. Anticholinesterase activity of fluorochloronitroacetic acid esters

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, Yu.Ya.; Brel, V.K. Martynov, I.V.

    1984-11-01

    Results are presented from pharmacologic and biochemical experiments leading to the conclusion that fluorochloronitroacetic acid esters have anticholinesterase activity. Since the esters caused muscular weakness in mice, experiments were performed on isolated tissue preparation. The biochemical experiments consisted of finding the biomolecular constants of irreversible inhibition of acetylcholinesterase by the esters, using acetylcholinesterase from human erythrocytes, as well as horse serum cholinesterase. The ethyl and n-propyl esters of halogen nitroacetic acid were used in all experiments. It was found that the propyl ester caused an increase in the force of individual contractions in the isolated muscle specimens, plus an inability of the muscle to retain tetanus. The substances were determined to have an anticholinesterase effect. The mechanism of cholinesterase inhibition is not yet known. It is probable that the substances acylate the serine hydroxyl of the esterase center of the cholinestersase. 7 references, 1 figure.

  17. 76 FR 82275 - Citric Acid and Certain Citrate Salts From the People's Republic of China: Extension of Time...

    Science.gov (United States)

    2011-12-30

    ... International Trade Administration Citric Acid and Certain Citrate Salts From the People's Republic of China... countervailing duty order on citric acid and certain citrate salts from the People's Republic of China (PRC). See Countervailing Duty Orders and Amendments of Final Affirmative Countervailing Duty Determinations: Citric...

  18. Citric and gluconic acid production from fig by Aspergillus niger using solid-state fermentation.

    Science.gov (United States)

    Roukas, T

    2000-12-01

    The production of citric and gluconic acids from fig by Aspergillus niger ATCC 10577 in solid-state fermentation was investigated. The maximal citric and gluconic acids concentration (64 and 490 g/kg dry figs, respectively), citric acid yield (8%), and gluconic acid yield (63%) were obtained at a moisture level of 75%, initial pH 7.0, temperature 30 degrees C, and fermentation time in 15 days. However, the highest biomass dry weight (40 g/kg wet substrate) and sugar utilization (90%) were obtained in cultures grown at 35 degrees C. The addition of 6% (w/w) methanol into substrate increased the concentration of citric and gluconic acid from 64 and 490 to 96 and 685 g/kg dry fig, respectively.

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

    Science.gov (United States)

    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 C4 plants but not from C3 plants. The δ(2)H values of citric acid decreased as the amount of citric acid added increased, whether the citric acid originated from C3 or C4 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.

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

    Science.gov (United States)

    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)

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

    Science.gov (United States)

    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.

  2. 77 FR 6061 - Citric Acid and Certain Citrate Salts From Canada: Preliminary Results of Antidumping Duty...

    Science.gov (United States)

    2012-02-07

    ... United States Pharmacopeia and has been mixed with a functional excipient, such as dextrose or starch... Notice; Citric Acid and Certain Citrate Salts from Canada and the People's Republic of China:...

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

    Science.gov (United States)

    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)

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  6. Acrylic Acid and Esters Will Be Oversupply

    Institute of Scientific and Technical Information of China (English)

    Zheng Chengwang

    2007-01-01

    @@ Drastic capacity growth The production capacity of acrylic acid in China has grown drastically in recent years. With the completion of the 80 thousand t/a acrylic acid and 130 thous and t/a acrylic ester project in Shenyang Paraffin Chemical Industrial Co., Ltd., (CCR2006,No. 31) the capacity of acrylic acid in China has reached 882 thousand t/a.

  7. Lipase Secretion and Citric Acid Production in Yarrowia lipolytica Yeast Grown on Animal and Vegetable Fat

    Directory of Open Access Journals (Sweden)

    Svetlana V. Kamzolova

    2005-01-01

    Full Text Available The aim of the study was to investigate the potentiality of the utilization of raw agro- -industrial fat for the biotechnological production of valuable products (lipase and citric acid by the yeast Yarrowia (Candida lipolytica. Thirty strains of the aforementioned species were investigated for their capability of lipase secretion and citric acid production on media containing animal fat or rapeseed oil as a sole carbon and energy source. Strain Y. lipolytica 704, exhibiting the highest lipase activity on rapeseed oil (2760 U/mL, was selected for the study of biochemical peculiarities of cell growth, and strain Y. lipolytica 187/1, exhibiting the maximum citric acid synthesis, was selected for the subsequent studies on citric acid production. A relationship between lipase production and residual rapeseed oil concentration was studied. The essential factor for lipase production was found to be the concentration of rapeseed oil in the medium, which should be no less than 5 g/L. Under optimal conditions of cultivation, citric acid production by rapeseed-oil-grown yeast Yarrowia lipolytica 187/1 amounted to 135 g/L; specific rate of citric acid production reached m(CA/m(cell=127 mg/(g·h; mass yield (YCA and energy yield (hCA were 1.55 and 0.41, respectively.

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

    Science.gov (United States)

    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.

  9. Effect of agitation and aeration on the citric acid production by Yarrowia lipolytica grown on glycerol.

    Science.gov (United States)

    Rywińska, Anita; Musiał, Izabela; Rymowicz, Waldemar; Zarowska, Barbara; Boruczkowski, Tomasz

    2012-01-01

    The effects of agitation rates from 400 to 900 rpm and aeration rates ranging from 0.18 to 0.6 vvm on biomass and citric acid production on glycerol media by acetate-negative mutants of Yarrowia lipolytica, Wratislavia 1.31 and Wratislavia AWG7, in batch culture were studied. The agitation rates of 800 and 900 rpm (at a constant aeration rate of 0.36 vvm) and aeration rates within the range of 0.24-0.48 vvm (at a constant agitation rate of 800 rpm), which generated dissolved oxygen concentration (DO) higher than 40%, were found the best for citric acid biosynthesis from glycerol. An increase in agitation rate (higher than 800 rpm) and aeration rate (higher than 0.36 vvm) had no impact on DO and citric acid production. The highest citric acid concentration (92.8 g/L) and yield (0.63 g/g) were obtained with Wratislavia 1.31 strain at 0.24 vvm. The highest volumetric citric acid production rate (1.15 g/Lh) and specific citric acid production rate (0.071 g/gh) were reached at 0.48 vvm.

  10. Basic properties of calcium phosphate cement containing different concentrations of citric acid solution

    Institute of Scientific and Technical Information of China (English)

    戴红莲; 闫玉华; 冯凌云; 李世普; 贺建华

    2002-01-01

    The properties of calcium phosphate cement consisting of α-tricalcium phosphate (α-TCP) and tetracalcium phosphate (TTCP) have been investigated by using a cement liquid that contained citric acid with concentration of 0.05 mol/L or higher. The relationship between the setting time of the system cement and the concentration of citric acid solution shows concave type curve. When solution concentration was 0.2 mol/L, the setting time was 8 min, which was the shortest. While the relationship between 24 h compressive strength of the cement and the citric acid concentration shows convex type curve. When solution concentration was 0.2 mol/L, the compressive strength was 39.0 MPa, which was the highest. Afterwards, the microstructure of the hardening product was observed by SEM, the effect of citric acid on the exothermic rate of hydrate reaction was studied by microcalorimeter, and the crushed specimens were subjected to X-ray diffraction. The results verified that the low citric acid concentration can accelerate the hydrate reaction rate of the α-TCP/TTCP system. However, the high citric acid concentration inhibited hydroxyapatite formation and retarded the rate of hydrate reaction of the α-TCP/TTCP cement.

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

    Science.gov (United States)

    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.

  12. Fed-batch production of citric acid by Candida lipolytica grown on n-paraffins.

    Science.gov (United States)

    Crolla, A; Kennedy, K J

    2004-05-13

    This study reports on the effects of fermentor agitation and fed-batch mode of operation on citric acid production from Candida lipolytica using n-paraffin as the carbon source. An optimum range of agitation speeds in the 800-1000 rpm range corresponding to Reynolds numbers of 50000-63000 (based on initial batch conditions) seemed to give the best balance between substrate utilization for biomass growth and citric acid production. Application of multiple fed-batch feedings can be used to extend the batch fermentation and increase final citric acid concentrations and product yield. The three-cycle fed-batch system increased overall citric acid yields to 0.8-1.0 g citricacid/g n-paraffin, approximately a 100% improvement in product yield from those observed in the single cycle fed-batch system and a 200% improvement over normal batch operation. The three-cycle fed-batch mode of operation also increased the final citric acid concentration to 42 g/l from about 12 and 6g/l for single fed-batch cycle and normal batch modes of operation, respectively. Increased citric acid concentrations in three-cycle fed-batch mode was achieved at longer fermentation times.

  13. Uptake of ozone to mixed sodium bromide/ citric acid solutions

    Science.gov (United States)

    Lee, Ming-Tao; Steimle, Emilie; Bartels-Rausch, Thorsten; Kato, Shunsuke; Lampimäki, Markus; Brown, Matthew; van Bokhoven, Jeroen; Nolting, Frithjof; Kleibert, Armin; Türler, Andreas; Ammann, Markus

    2013-04-01

    Sea-salt solution - air interfaces play an important role in the chemistry of the marine boundary layer. The reaction of ozone (O3) with bromide is of interest in the context of formation of photolabile halogens (Br2, BrCl) in the marine boundary layer. Recent experiments have suggested that the bromide oxidation rate is related to the surface concentration of bromide [1] and inversely related to the gas phase concentration of O3, an indication for a precursor mediated reaction at the surface [2]. So far, the effect of organics (such as those occurring at the ocean surface or in marine aerosols) on the reaction of O3 with bromide aerosols has not been studied yet. In our study we investigate the uptake kinetics of O3 to a mixed solution of sodium bromide (NaBr) and citric acid (CA), which represents highly oxidized organic compounds present in the environment, with a well-established coated wall flow tube technique, which leads to exposure of the film to O3 allowing the heterogeneous reactions to take place and the loss of O3 being measured. The results indicate that the uptake of O3 to the films with the higher bromide concentrations (0.34M and 4M) is independent of the gas phase concentration and roughly consistent with uptake limited by reaction in the bulk. For the lower bromide concentration (84mM), however, we observe a trend of the uptake coefficient to decrease with increasing O3 concentration, indicating an increasing importance of a surface reaction. In an attempt to constrain the kinetic data, we employed X-ray photoelectron spectroscopy (XPS) to get insight into the surface composition of the aqueous solution - air interface. Previous XPS studies have shown that halide ion concentrations are enhanced at the aqueous solution air interface [3-4], which likely promotes the surface reactions of bromide or iodide with O3. A first XPS study of ternary solutions of KI with butanol indicated the importance of specific interactions of the cation with the alcohol

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

    Science.gov (United States)

    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

  15. 21 CFR 172.854 - Polyglycerol esters of fatty acids.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Polyglycerol esters of fatty acids. 172.854 Section... HUMAN CONSUMPTION Multipurpose Additives § 172.854 Polyglycerol esters of fatty acids. Polyglycerol esters of fatty acids, up to and including the decaglycerol esters, may be safely used in food in...

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

    Science.gov (United States)

    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.

  17. Citric acid production by Candida species grown on a soy-based crude glycerol.

    Science.gov (United States)

    West, Thomas P

    2013-01-01

    Citric acid was produced by five species of the yeast Candida after growth on a medium containing soy biodiesel-based crude glycerol. After growth on a medium containing 10 g L(-1) or 60 g L(-1) crude glycerol for 168 hr at 30°C, Candida parapsilosis ATCC 7330 and C. guilliermondii ATCC 9058 produced the highest citric acid levels. On 10 g L(-1) or 60 g L(-1) crude glycerol for 168 hr at 30°C, the citric acid level produced by C. parapsilosis ATCC 7330 was 1.8 g L(-1) or 11.3 g L(-1), respectively, while C. guilliermondii ATCC 9058 produced citric acid concentrations of 3.0 g L(-1) or 10.4 g L(-1), respectively. Biomass production by C. guilliermondii ATCC 9058 on 10 g L(-1) or 60 g L(-1) crude glycerol for 168 hr at 30°C was highest at 1.2 g L(-1) or 6.9 g L(-1), respectively. The citric acid yields observed for C. guilliermondii ATCC 9058 after growth on 10 g L(-1) or 60 g L(-1) crude glycerol (0.35 g g(-1) or 0.21 g g(-1), respectively) were generally higher than for the other Candida species tested. When similar crude glycerol concentrations were present in the culture medium, citric acid yields observed for some of the Candida species utilized in this study were about the same or higher compared to citric acid yields by Yarrowia lipolytica strains. Based on the findings, it appeared that C. guilliermondii ATCC 9058 was the most effective species utilized, with its citric acid production being similar to what has been observed when citric acid-producing strains of Y. lipolytica were grown on crude glycerol under batch conditions that could be of significance to biobased citric acid production.

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

    Science.gov (United States)

    Negrón-Mendoza, A.; Ramos-Bernal, S.

    2015-07-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Negrón-Mendoza, A., E-mail: negron@nucleares.unam.mx; Ramos-Bernal, S. [Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, UNAM. Cd. Universitaria, A. P. 70-543, 04510 México, D. F. México (Mexico)

    2015-07-23

    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.

  20. Influence of ingestion of aluminum, citric acid and soil on mineral metabolism of lactating beef cows.

    Science.gov (United States)

    Allen, V G; Horn, F P; Fontenot, J P

    1986-05-01

    Lactating beef cows (16 Hereford and 34 Angus, 430 kg average body weight, aged 8 to 10 yr) were fed a basal diet containing 200 micrograms/g Al alone or supplemented with Al-citrate, citric acid, soil or soil plus citric acid for 56 d. Diets containing Al-citrate, soil and soil plus citric acid contained 1,730, 1,870 and 1,935 micrograms/g Al, dry-basis, respectively. Adding soil to the diet also increased Mg and Fe content of the diet. Aluminum values in ruminal contents of beef cows fed the basal alone or supplemented with citric acid, Al-citrate, soil or soil plus citric acid were 800, 990, 2,930, 3,410 and 2,910 micrograms/g, air-dry basis, respectively. Serum Mg and inorganic P declined (P less than .01) and urinary Ca concentration increased (P less than .01) for cows fed Al-citrate. By d 56, serum Mg was 1.5 and 2.2 mg/dl, and serum P was 3.8 and 6.8 mg/dl, for cows fed Al-citrate and basal diets, respectively. Calcium concentrations in urine were 281 and 11 micrograms/g for cows fed Al-citrate and basal diets, respectively. Citric acid, soil and soil plus citric acid had no detrimental effects on serum Mg and inorganic P, or urinary Ca concentration. By d 56, serum Ca was higher (P less than .06) in cows fed Al-citrate, compared with cows on the other four diets. Bone Ca, P, Zn and percent ash were not significantly affected by treatment but bone Mg tended to be slightly lower (P less than .07) for cows fed Al-citrate.(ABSTRACT TRUNCATED AT 250 WORDS)

  1. Heavy Metal Removal from Commercially-available Fruit Juice Packaged Products by Citric Acid

    Directory of Open Access Journals (Sweden)

    Shabnam Mohammadi

    2015-03-01

    Full Text Available There has been an increasing trend in the production and consumption of local and imported fruit juices in Iran. The presence of impurities and foreign matter in finished products for human consumption is of great concern because they present health hazards when they exceed beneficial limits. The manufacture of juices requires special attention in terms of purity and the sources of water and its purification are crucial for maintaining quality and safety. Biosorption can be defined as the removal of metal or metalloid species, compounds and particulates from solution by biological material. citric acid content of beverages may be useful in nutrition therapy for calcium urolithiasis, achieving therapeutic urinary citrate concentration is one clinical target in the medical management of calcium urolithiasis. Information on the citric acid content of fruit juices and commercially-available formulations is not widely known. Levels of heavy metals: Lead, Cadmium and Nickel in 180 selected fruit juice commercially available packaged samples (Pineapple, Orange, Mango, Tropical, Cherry& Grape purchased from Tehran local Market in 2014. Heavy metals were determined using atomic absorption spectrophotometer (AAS by wet digestion method in Pharmaceutical Sciences Branch, Islamic Azad University Tehran-Iran. From the obtained result Ni, Cd and Pb were detectable in 85% of samples especially in Mango and Tropical juices. The efficiency removal of Nickel, lead and Cadmium and neutralization of calculus contain of juice by Citric acid as a chelating were carried out by using of Atomic Absorption Spectrophotometry technique. The result demonstrated the complexation formulating between the citric acid and heavy metals. The high efficiency of Citric acid played an important role in removal of lead and cadmium in addition to this removal were increased by increasing the citric acid. The enhancing of citric acid in removal of lead and cadmium caused to create a

  2. The effect of citric acid and citrate on protoplasmic droplet of bovine epididymal sperms

    Directory of Open Access Journals (Sweden)

    Keivan Abdy

    2011-11-01

    Full Text Available AbstractFor evaluation of citric acid and citrate effects on bovine epididymal protoplasmic droplets, fifty bovine testes were collected in the October 2007 till June 2008 from Urmia slaughterhouse and transported to the laboratory in a cool container filled with 5 °C ice pack. Caudal epididymis was incised and sperm cells were put into Petri dishes containing hams f10 media with 10% fetal calf serum (FCS, which were kept in 37 °C, CO2 incubator. Then sperm cells were counted and 50-milion per mL concentration was prepared. After this stage, three dilutions of citric acid (0.1, 0.2, 0.3 N and one dilution of citrate (1N, based on normal osmolarity and normal pH were added to a micro tube containing 25 milion per mL sperm. Then one-step eosin-nigrosin staining in 30-60-120-240-360 minutes was performed and slides were evaluated with 1000-x phase contrast microscope and 200 sperm cells per slide were counted. The results revealed significant difference between blank and citric acid 0.3 N. The proportion of protoplasmic droplet in group consisting of 0.3 N acid citric in 120-240-360 minutes, was significantly lower than that of blank (P < 0.05. There was no significant difference between citrate – blank and citric acid 0.1N-blank groups, but after 240 minutes significant difference was observed between blank & citric acid 0.2 N (P < 0.05. In conclusions citric acid based on dilution and time duration can reduce the proportion of bovine epididymal sperm cytoplasmic droplets.

  3. Novel PH Sensitive Nanocarrier Agents Based on Citric Acid Dendrimers Containing Conjugated β-Cyclodextrins

    Directory of Open Access Journals (Sweden)

    Hassan Namazi

    2011-06-01

    Full Text Available Introduction: In this work, the use of β-cyclodextrine (β-CD-modified dendrimers as a nanocapsule with a biocompatible shell have studied. β-CD-modified dendrimers have designed and synthesized to enhance the loading capacity of the final dendrimers with encapsulation properties. Methods: To achieve β-CD-modified dendrimers, first citric acid dendrimers were synthesized and then the end functional groups of dendrimers were grafted to β-CD through ester linkages. The molecular structures of resulted dendrimers were verified using common spectroscopic methods such as 1H NMR, FT-IR and the diameters of obtained nanocarriers were evaluated with using dynamic light scattering (DLS experiments. The isolated dendrimers were utilized as the drug delivery agents and the encapsulation and the controlled release of guest drug molecule Naltrexone (NLX was investigated in different pH’s using UV spectroscopy method. Results: It was established that the loading capacity of dendrimers depend on several factors such as their generation and the structure and number of conjugated modifier end groups. Conclusion: Increasing in the number of branches and the size of interior voids and number of conjugated β-CDs cause to enhance the loading capacity.

  4. Modeling of the selective pertraction of carboxylic acids obtained by citric fermentation

    Directory of Open Access Journals (Sweden)

    Cascaval Dan

    2004-01-01

    Full Text Available Facilitated pertraction was applied for the selective separation of citric, maleic and succinic acids from a mixture obtained by citric fermentation. The pertraction equipment included a U-shaped cell containing 1,2-dichloro-ethane as the liquid membrane and Amberlite LA-2 as the carrier. The experimental data indicated that maleic and succinic acids can be initially selectively separated from citric acid, followed by the selectively separation of maleic acid from succinic acid. Using statistical analysis and a second order factorial experiment, two mathematical correlations describing the influence of the main process variables on pertraction selectivity were established. For both extraction systems, the considered variables controlled the extraction process to an extent of 92.9-99.9%, the carrier concentration inside the liquid membrane exhibiting the most important influence.

  5. Preparation of Slowly Digestible Starch by Citric Acid-hydrolysis with Autoclaving

    Directory of Open Access Journals (Sweden)

    Hansong Yu

    2015-03-01

    Full Text Available Aim of study is to produce Slowly Digestible Starch (SDS by a combination of citric acid-hydrolysis and autoclaving from raw corn starch. The effects of citric acid concentration, acid hydrolysis time, temperature and refrigeration and retro gradation time on the formation of SDS were investigated. The optimal process conditions optimized by Box-Benhnken’s central composite design and response surface analysis was as follows: concentration of citric acid is 0.08 M, acid hydrolyzed at 116°C for 14.5 min, and then stored at 0°C for 72 h. Under these optimal conditions, the content of SDS peaked at 19.38%.

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

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yang, E-mail: liuyang@cczu.edu.cn [Institute of Biomedical Engineering and Health Sciences, Changzhou University, Changzhou 213164 (China); Engineering Research Center of Nano-Geo Materials of Ministry of Education, China University of Geosciences, Wuhan 430074 (China); School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 (China); Shen, Xin; Zhou, Huan [Institute of Biomedical Engineering and Health Sciences, Changzhou University, Changzhou 213164 (China); Wang, Yingjun [School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 (China); Deng, Linhong, E-mail: dlh@cczu.edu.cn [Institute of Biomedical Engineering and Health Sciences, Changzhou University, Changzhou 213164 (China)

    2016-05-01

    Graphical abstract: - Highlights: • Chitosan film was modified by surface grafting of citric acid. • The modified film has good hydrophilicity and moisture-retaining capacity. • The citric acid grafting treatment significantly promote the biomineralization. • MC3T3-E1 osteoblasts research confirms the biocompatibility of the film. - Abstract: 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.

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

    Science.gov (United States)

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

    Science.gov (United States)

    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

  9. Citric and Oxalic Acids Effect on Pb and Zn Uptake by Maize and Winter Wheat

    Institute of Scientific and Technical Information of China (English)

    Wang Xinmin; Hou Yanlin; Jie Xiaolei

    2004-01-01

    A pot experiment was conducted to investigate the influence of citric and oxalic acids effect on Pb and Zn uptake by corn and winter wheat.The experiment was employed with citric acid (CA)applied at 3 rates (0, 1.5 and 3.0 mmol kg-1 soil),oxalic acid (OA) at 3 rates (0, 1.5 and 3.0mmol kg-1soil) and citric acid combined with oxalic acid (1.5mmol citric acid combined with 1.5 mmol oxalic acid kg-1). Two types of soil were chose in the experiment.One was collected from the agricultural soil near a battery-recycling factory in Anhui province, China (site A) and the other was collected from a Pb-Zn mine residues in Hunan province, China (site B). The results showed that soil pH varied with the different treatment of citric and oxalic acids. However, there were no differences in all the treatments. 3.0mmol CA kg-1 soil addition significantly increased the concentrations of the CaCl2-extractable Pb and Zn and other treatments have no significantly increased.The highest shoot concentrations of Pb and Zn in both species occurred in application of 3.0 mmol CA/kg-1 soil and shoot concentrations of Pb and Zn in both species were significantly higher than the controls in this treatment. Shoot yields declined with application of citric and oxalic acids, indicating that the plants were sensitive to the toxicity of the metals or the amendments. The highest Pb uptake values by maize and wheat were112.3 and 77.2 μg pot-1in soil of site A, and occurred with the control and 3.0 mmol CA/kg-1 soil respectively.

  10. Effects of Citric Acid and l-Carnitine on Physical Fatigue.

    Science.gov (United States)

    Sugino, Tomohiro; Aoyagi, Sayaka; Shirai, Tomoko; Kajimoto, Yoshitaka; Kajimoto, Osami

    2007-11-01

    We examined the effects of citric acid and l-carnitine administration on physical fatigue. In a double-blind, placebo-controlled, 3-way crossover study, 18 healthy volunteers were randomized to oral citric acid (2,700 mg/day), l-carnitine (1,000 mg/day), or placebo for 8 days. The fatigue-inducing physical task consisted of workload trials on a cycle ergometer at fixed workloads for 2 h on 2 occasions. Before the physical load, salivary chromogranin A, measured as a physiological stress marker, was lower in the group given citric acid than in the group given placebo. Also, after the physical load, the subjective feeling of fatigue assessed with a visual analogue scale was lower in the citric acid group than in the placebo group. In contrast, l-carnitine had no effect on chromogranin A or subjective fatigue. These results suggest that citric acid reduces physiological stress and attenuates physical fatigue, whereas l-carnitine does not.

  11. Citric acid cycle intermediates as ligands for orphan G-protein-coupled receptors.

    Science.gov (United States)

    He, Weihai; Miao, Frederick J-P; Lin, Daniel C-H; Schwandner, Ralf T; Wang, Zhulun; Gao, Jinhai; Chen, Jin-Long; Tian, Hui; Ling, Lei

    2004-05-13

    The citric acid cycle is central to the regulation of energy homeostasis and cell metabolism. Mutations in enzymes that catalyse steps in the citric acid cycle result in human diseases with various clinical presentations. The intermediates of the citric acid cycle are present at micromolar concentration in blood and are regulated by respiration, metabolism and renal reabsorption/extrusion. Here we show that GPR91 (ref. 3), a previously orphan G-protein-coupled receptor (GPCR), functions as a receptor for the citric acid cycle intermediate succinate. We also report that GPR99 (ref. 4), a close relative of GPR91, responds to alpha-ketoglutarate, another intermediate in the citric acid cycle. Thus by acting as ligands for GPCRs, succinate and alpha-ketoglutarate are found to have unexpected signalling functions beyond their traditional roles. Furthermore, we show that succinate increases blood pressure in animals. The succinate-induced hypertensive effect involves the renin-angiotensin system and is abolished in GPR91-deficient mice. Our results indicate a possible role for GPR91 in renovascular hypertension, a disease closely linked to atherosclerosis, diabetes and renal failure.

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

    Science.gov (United States)

    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.

  13. Citric acid as multifunctional agent in blowing films of starch/PBAT

    Directory of Open Access Journals (Sweden)

    Patrícia Salomão Garcia

    2011-09-01

    Full Text Available Citric acid was used as a compatibilizer in the production of starch and PBAT films plasticized with glycerol and processed by blow extrusion. Films produced were characterized by WVP, mechanical properties, FT-IR-ATR and SEM. WPV ranged from 3.71 to 12.73×10-11 g m-1 s-1 Pa-1, while tensile strength and elongation at break ranged from 1.81 to 7.15 MPa and from 8.61 to 23.63%, respectively. Increasing the citric acid concentration improved WVP and slightly decreased film resistance and elongation. The films micrographs revealed a more homogeneous material with the addition of citric acid. However, the infrared spectra revealed little about cross-linking esterification reaction

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

    Science.gov (United States)

    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.

  15. Wheat straw hemicelluloses added with cellulose nanocrystals and citric acid. Effect on film physical properties.

    Science.gov (United States)

    Pereira, Paulo H F; Waldron, Keith W; Wilson, David R; Cunha, Arcelina P; Brito, Edy S de; Rodrigues, Tigressa H S; Rosa, Morsyleide F; Azeredo, Henriette M C

    2017-05-15

    Wheat straw has been used as a source of hemicelluloses (WSH) and cellulose nanocrystals (CNC) for the elaboration of biodegradable films. Different films have been formed by using WSH as a matrix and different contents of CNC and citric acid. The predominant hemicelluloses were arabinoxylans. CNC reinforced the films, improving tensile strength and modulus, water resistance and water vapor barrier. Citric acid, on the other hand, presented concomitant plasticizing and crosslinking effects (the latter also evidenced by FTIR), probably due to a crosslinking extension by glycerol. The use of 5.9wt% CNC and 30wt% citric acid was defined as optimal conditions, resulting in minimum water sensitivity and permeability, while maintaining a good combination of tensile properties. Under those conditions, the films presented enhanced modulus, elongation, water resistance, and barrier to water vapor when compared to the control WSH film, and might be used for wrapping or coating a variety of foods.

  16. Corrosion Inhibition of Mild Steel in Citric Acid by Aqueous Extract of Piper Nigrum L.

    Directory of Open Access Journals (Sweden)

    P. Matheswaran

    2012-01-01

    Full Text Available The inhibition efficiency (IE of an aqueous extract of Piper Nigrum L. in controlling corrosion of mild steel at pH 12 has been evaluated by weight loss method in the absence and presence of inhibitor in citric acid medium at different concentration. The result showed that the corrosion inhibition efficiency of these compounds was found to vary with the different concentration at two hour time interval at room temperature. Also, it was found that the corrosion inhibition behaviour of Piper Nigrum L. is greater in 2 N Citric acid than 1 N Citric acid medium. So Piper Nigrum L. can be used has a good inhibitor for preventing mild steel material which is used in many construction purpose.

  17. Citric Acid Production by the Aspergillus niger Isolated from the Microflora of Iran

    Directory of Open Access Journals (Sweden)

    R.Yazdanparast

    1995-08-01

    Full Text Available Citric acid production by A.niger, isolated from the microflora of Iran, has been investigated in liquid and semi-solid states using growth media with different compositions. In 2% media made of Rocheh grape pomace or sabouraud dextrose, the yield of citric acid production was 0.7 g per Kg of the pomace; and the yield decreased by 50% in 2% saghal solian grape pomace medium. However, in 40% (W/W saghal solian semi-solid medium containing 3% methanol, the yield of citric acid production has improved to 80 g per Kg of pomace in stationary mode of production and to 120 g per Kg of pomace in the rolling mode of fermentation.

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

    Science.gov (United States)

    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.

  19. Citric acid production by selected mutants of Aspergillus niger from cane molasses.

    Science.gov (United States)

    Ikram-Ul, Haq; Ali, Sikander; Qadeer, M A; Iqbal, Javed

    2004-06-01

    The present investigation deals with citric acid production by some selected mutant strains of Aspergillus niger from cane molasses in 250 ml Erlenmeyer flasks. For this purpose, a conidial suspension of A. niger GCB-75, which produced 31.1 g/l citric acid from 15% (w/v) molasses sugar, was subjected to UV-induced mutagenesis. Among the 3 variants, GCM-45 was found to be a better producer of citric acid (50.0 +/- 2a) and it was further improved by chemical mutagenesis using N-methyl, N-nitro-N-nitroso-guanidine (MNNG). Out of 3,2-deoxy-D-glucose resistant variants, GCMC-7 was selected as the best mutant, which produced 96.1 +/- 1.5 g/l citric acid 168 h after fermentation of potassium ferrocyanide and H2SO4 pre-treated blackstrap molasses in Vogel's medium. On the basis of kinetic parameters such as volumetric substrate uptake rate (Qs), and specific substrate uptake rate (qs), the volumetric productivity, theoretical yield and specific product formation rate, it was observed that the mutants were faster growing organisms and produced more citric acid. The mutant GCMC-7 has greater commercial potential than the parental strain with regard to citrate synthase activity. The addition of 2.0 x 10(-5) M MgSO4 x 5H2O into the fermentation medium reduced the Fe2+ ion concentration by counter-acting its deleterious effect on mycelial growth. The magnesium ions also induced a loose-pelleted form of growth (0.6 mm, diameter), reduced the biomass concentration (12.5 g/l) and increased the volumetric productivity of citric acid monohydrate (113.6 +/- 5 g/l).

  20. Naturally Occurring Cinnamic Acid Sugar Ester Derivatives

    Directory of Open Access Journals (Sweden)

    Yuxin Tian

    2016-10-01

    Full Text Available Cinnamic acid sugar ester derivatives (CASEDs are a class of natural product with one or several phenylacrylic moieties linked with the non-anomeric carbon of a glycosyl skeleton part through ester bonds. Their notable anti-depressant and brains protective activities have made them a topic of great interest over the past several decades. In particular the compound 3′,6-disinapoylsucrose, the index component of Yuanzhi (a well-known Traditional Chinese Medicine or TCM, presents antidepressant effects at a molecular level, and has become a hotspot of research on new lead drug compounds. Several other similar cinnamic acid sugar ester derivatives are reported in traditional medicine as compounds to calm the nerves and display anti-depression and neuroprotective activity. Interestingly, more than one third of CASEDs are distributed in the family Polygalaceae. This overview discusses the isolation of cinnamic acid sugar ester derivatives from plants, together with a systematic discussion of their distribution, chemical structures and properties and pharmacological activities, with the hope of providing references for natural product researchers and draw attention to these interesting compounds.

  1. 40 CFR 721.1732 - Nitrobenzoic acid octyl ester.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Nitrobenzoic acid octyl ester. 721... Substances § 721.1732 Nitrobenzoic acid octyl ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as nitrobenzoic acid octyl ester (PMN...

  2. 40 CFR 721.5310 - Neononanoic acid, ethenyl ester.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Neononanoic acid, ethenyl ester. 721... Substances § 721.5310 Neononanoic acid, ethenyl ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as neononanoic acid, ethenyl ester (PMN...

  3. 40 CFR 721.4158 - Hexadecanoic acid, ethenyl ester.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Hexadecanoic acid, ethenyl ester. 721... Substances § 721.4158 Hexadecanoic acid, ethenyl ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as hexadecanoic acid, ethenyl ester (PMN...

  4. 40 CFR 721.4215 - Hexanedioic acid, diethenyl ester.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Hexanedioic acid, diethenyl ester. 721... Substances § 721.4215 Hexanedioic acid, diethenyl ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as hexanedioic acid, diethenyl ester (PMN...

  5. 75 FR 71556 - Polyoxyalkylated Glycerol Fatty Acid Esters; Tolerance Exemption

    Science.gov (United States)

    2010-11-24

    ... AGENCY 40 CFR Part 180 Polyoxyalkylated Glycerol Fatty Acid Esters; Tolerance Exemption AGENCY... from the requirement of a tolerance for residues of polyoxyalkylated glycerol fatty acid esters; the... ethylene oxide or propylene oxide, also known as polyoxyalkylated glycerol fatty acid esters, when used as...

  6. 40 CFR 721.2950 - Carboxylic acid glycidyl esters.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Carboxylic acid glycidyl esters. 721... Substances § 721.2950 Carboxylic acid glycidyl esters. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substance identified generically as carboxylic acid glycidyl ester...

  7. Effects of Citric Acid and l-Carnitine on Physical Fatigue

    OpenAIRE

    Sugino, Tomohiro; Aoyagi, Sayaka; Shirai, Tomoko; Kajimoto, Yoshitaka; Kajimoto, Osami

    2007-01-01

    We examined the effects of citric acid and l-carnitine administration on physical fatigue. In a double-blind, placebo-controlled, 3-way crossover study, 18 healthy volunteers were randomized to oral citric acid (2,700 mg/day), l-carnitine (1,000 mg/day), or placebo for 8 days. The fatigue-inducing physical task consisted of workload trials on a cycle ergometer at fixed workloads for 2 h on 2 occasions. Before the physical load, salivary chromogranin A, measured as a physiological stress marke...

  8. The effects of citric acid on the hydration of calcium phosphate cement

    Institute of Scientific and Technical Information of China (English)

    DAI Hong-lian; YAN Yu-hua; WANG You-fa; LI Shi-pu

    2001-01-01

    @@ INTRODUCTION Calcium phosphate cements (CPC) overcome the practical disadvantages of blocks or granulesl can be handled as a paste and sit in situ. Their structure and composition close to that of HAP make them biocompatible materials. 2 The conventional calcium phosphate cement had some problems such as long setting time (30~60 min) and low compressive strength, etc. In our system, an α-TCP/TTCP powder mixture was mixed with water containing citric acid to control the setting time and compressive strength. In this paper, the effects of various concentration citric acid solutions on the properties of the cement are reported.

  9. Effects of Citric Acid and l-Carnitine on Physical Fatigue

    OpenAIRE

    Sugino, Tomohiro; Aoyagi, Sayaka; SHIRAI, Tomoko; Kajimoto, Yoshitaka; Kajimoto, Osami

    2007-01-01

    We examined the effects of citric acid and l-carnitine administration on physical fatigue. In a double-blind, placebo-controlled, 3-way crossover study, 18 healthy volunteers were randomized to oral citric acid (2,700 mg/day), l-carnitine (1,000 mg/day), or placebo for 8 days. The fatigue-inducing physical task consisted of workload trials on a cycle ergometer at fixed workloads for 2 h on 2 occasions. Before the physical load, salivary chromogranin A, measured as a physiological stress marke...

  10. Oxalic acid production by citric acid-producing Aspergillus niger overexpressing the oxaloacetate hydrolase gene oahA.

    Science.gov (United States)

    Kobayashi, Keiichi; Hattori, Takasumi; Honda, Yuki; Kirimura, Kohtaro

    2014-05-01

    The filamentous fungus Aspergillus niger is used worldwide in the industrial production of citric acid. However, under specific cultivation conditions, citric acid-producing strains of A. niger accumulate oxalic acid as a by-product. Oxalic acid is used as a chelator, detergent, or tanning agent. Here, we sought to develop oxalic acid hyperproducers using A. niger as a host. To generate oxalic acid hyperproducers by metabolic engineering, transformants overexpressing the oahA gene, encoding oxaloacetate hydrolase (OAH; EC 3.7.1.1), were constructed in citric acid-producing A. niger WU-2223L as a host. The oxalic acid production capacity of this strain was examined by cultivation of EOAH-1 under conditions appropriate for oxalic acid production with 30 g/l glucose as a carbon source. Under all the cultivation conditions tested, the amount of oxalic acid produced by EOAH-1, a representative oahA-overexpressing transformant, exceeded that produced by A. niger WU-2223L. A. niger WU-2223L and EOAH-1 produced 15.6 and 28.9 g/l oxalic acid, respectively, during the 12-day cultivation period. The yield of oxalic acid for EOAH-1 was 64.2 % of the maximum theoretical yield. Our method for oxalic acid production gave the highest yield of any study reported to date. Therefore, we succeeded in generating oxalic acid hyperproducers by overexpressing a single gene, i.e., oahA, in citric acid-producing A. niger as a host.

  11. Influence of Citric Acid on the Metal Release of Stainless Steels

    Energy Technology Data Exchange (ETDEWEB)

    Mazinanian, N.; Wallinder, I. Odnevall; Hedberg, Y. S. [KTH Royal Institute of Technology, School of Chemical Science and Engineering, Department of Chemistry, Division of Surface and Corrosion Science, Stockholm (Sweden)

    2015-08-15

    Knowledge of how metal releases from the stainless steels used in food processing applications and cooking utensils is essential within the framework of human health risk assessment. A new European standard test protocol for testing metal release in food contact materials made from metals and alloys has recently been published by the Council of Europe. The major difference from earlier test protocols is the use of citric acid as the worst-case food simulant. The objectives of this study were to assess the effect of citric acid at acidic, neutral, and alkaline solution pH on the extent of metal release for stainless steel grades AISI 304 and 316, commonly used as food contact materials. Both grades released lower amounts of metals than the specific release limits when they were tested according to test guidelines. The released amounts of metals were assessed by means of graphite furnace atomic absorption spectroscopy, and changes in the outermost surface composition were determined using X-ray photoelectron spectroscopy. The results demonstrate that both the pH and the complexation capacity of the solutions affected the extent of metal release from stainless steel and are discussed from a mechanistic perspective. The outermost surface oxide was significantly enriched in chromium upon exposure to citric acid, indicating rapid passivation by the acid. This study elucidates the effect of several possible mechanisms, including complex ion- and ligand-induced metal release, that govern the process of metal release from stainless steel under passive conditions in solutions that contain citric acid.

  12. 77 FR 47370 - Citric Acid and Certain Citrate Salts from the People's Republic of China: Intent To Rescind...

    Science.gov (United States)

    2012-08-08

    ... International Trade Administration Citric Acid and Certain Citrate Salts from the People's Republic of China... countervailing duty (CVD) order on citric acid and certain citrate salts from the People's Republic of China.\\1... functional excipient, such as dextrose or starch, where the excipient constitutes at least 2 percent,...

  13. 78 FR 34642 - Citric Acid and Certain Citrate Salts From the People's Republic of China: Preliminary Results of...

    Science.gov (United States)

    2013-06-10

    ... dihydrate and anhydrous forms of sodium citrate, otherwise known as citric acid sodium salt, and the monohydrate and monopotassium forms of potassium citrate.\\1\\ Sodium citrate also includes both trisodium... monosodium salt, respectively. Citric acid and sodium citrate are classifiable under 2918.14.0000 and...

  14. 78 FR 54625 - Citric Acid and Certain Citrate Salts From the People's Republic of China: Notice of Partial...

    Science.gov (United States)

    2013-09-05

    ... International Trade Administration Citric Acid and Certain Citrate Salts From the People's Republic of China... citric acid and certain citrate salts from the People's Republic of China (PRC) covering the period of...; Opportunity To Request Administrative Review, 78 FR 25423 (May 1, 2013). \\2\\ Archer Daniels Midland...

  15. CROSS-LINKING OF CHITOSAN WITH GLUTARALDEHYDE IN THE PRESENCE OF CITRIC ACID — A NEW GELLING SYSTEM

    Institute of Scientific and Technical Information of China (English)

    Yu Fang; Dao-dao Hu

    1999-01-01

    The procedure for preparing a new type of uniform and porous chitosan gel from citric acid medium is described. Its swelling behavior in different media was compared with those of the gels prepared by other methods. The ultrastructure of the xerogel prepared from citric acid was characterized using electron microscopy (SEM).

  16. Acidification of formula with citric acid is equally effective and better tolerated than acidification with hydrochloric acid.

    Science.gov (United States)

    Mehall, John R; Saltzman, Daniel A; Jackson, Richard J; Smith, Samuel D

    2002-08-01

    To determine whether acidification of formula with citric acid is equally protective against bacterial translocation and gut colonization but better tolerated than acidification with hydrochloric acid in neonatal rabbits. Paired animal model with control. Animal laboratory. Premature neonatal New Zealand rabbit pups. A standard neonatal rabbit model in two versions, a bacterial challenge and a no bacterial challenge model, was used to assess bacterial translocation and gut colonization. Two hundred forty-six rabbit pups were delivered by cesarean section 1 day premature and randomly placed into two groups sorted by type of formula acidification (hydrochloric acid or citric acid). Pups were gavage fed pH 3 kitten formula every 12 hrs. Ranitidine hydrochloride at 20 mg x kg(-1) x day(-1) was added to all formula. Bacterial challenge animals were given 1 x 10(6) colony-forming units/mL of Enterobacter cloacae with the third feeding. Animals in the no bacterial challenge group received no bacterial challenge. Animals were killed on day of life 3, and the liver, spleen, mesenteric lymph nodes, and cecum were sequentially harvested and cultured. Organs were qualitatively judged for growth, whereas cecal cultures were quantified as colony-forming units/gram. Stomach biopsies were performed to look for mucosal damage. Long-term tolerance was assessed in 48 pups fed formula acidified to pH 3 with either hydrochloric acid or citric acid and 20 animals fed pH 7 formula without ranitidine. Weight gain and mortality rate were followed for 14 days. Gut colonization and bacterial translocation to liver, spleen, and mesenteric lymph nodes were equivalent between citric acid and hydrochloric acid in both bacterial challenge and no bacterial challenge models. Long term, citric acid animals exceeded hydrochloric acid animals in daily weight gain and survival (p formula with citric acid is equally protective against bacteria but better tolerated than acidification with hydrochloric

  17. The extraordinary mitochondrion and unusual citric acid cycle in Trypanosoma brucei.

    Science.gov (United States)

    van Hellemond, J J; Opperdoes, F R; Tielens, A G M

    2005-11-01

    African trypanosomes are parasitic protozoa that cause sleeping sickness and nagana. Trypanosomes are not only of scientific interest because of their clinical importance, but also because these protozoa contain several very unusual biological features, such as their specially adapted mitochondrion and the compartmentalization of glycolytic enzymes in glycosomes. The energy metabolism of Trypanosoma brucei differs significantly from that of their hosts and changes drastically during the life cycle. Despite the presence of all citric acid cycle enzymes in procyclic insect-stage T. brucei, citric acid cycle activity is not used for energy generation. Recent investigations on the influence of substrate availability on the type of energy metabolism showed that absence of glycolytic substrates did not induce a shift from a fermentative metabolism to complete oxidation of substrates. Apparently, insect-stage T. brucei use parts of the citric acid cycle for other purposes than for complete degradation of mitochondrial substrates. Parts of the cycle are suggested to be used for (i) transport of acetyl-CoA units from the mitochondrion to the cytosol for the biosynthesis of fatty acids, (ii) degradation of proline and glutamate to succinate, (iii) generation of malate, which can then be used for gluconeogenesis. Therefore the citric acid cycle in trypanosomes does not function as a cycle.

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

    Science.gov (United States)

    Kim, Ji-Han; Hong, Go-Eun; Lim, Ki-Won; Park, Woojoon; Lee, Chi-Ho

    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 (psous vide chicken breast at 2% and 5% citric acid concentrations.

  19. Visualization data on the freezing process of micrometer-scaled aqueous citric acid drops

    Directory of Open Access Journals (Sweden)

    Anatoli Bogdan

    2017-02-01

    Full Text Available The visualization data (8 movies presented in this article are related to the research article entitled “Freezing and glass transitions upon cooling and warming and ice/freeze-concentration-solution morphology of emulsified aqueous citric acid” (A. Bogdan, M.J. Molina, H. Tenhu, 2016 [1]. The movies recorded in-situ with optical cryo-miscroscopy (OC-M demonstrate for the first time freezing processes that occur during the cooling and subsequent warming of emulsified micrometer-scaled aqueous citric acid (CA drops. The movies are made publicly available to enable critical or extended analyzes.

  20. Influence of citric acid on SnO2 nanoparticles synthesized by wet chemical processes

    CSIR Research Space (South Africa)

    Sikhwivhilu, LM

    2010-10-01

    Full Text Available Tin oxide (SnO2) nanoparticles with size range of 19 to 100 nm were successfully synthesized using wet chemical process (i.e. chemical precipitation and sol-gel processes). The results showed that variation of citric acid concentration directly...

  1. Effects of Solution Hydrodynamics on Corrosion Inhibition of Steel by Citric Acid in Cooling Water

    Science.gov (United States)

    Ashassi-Sorkhabi, H.; Asghari, E.; Mohammadi, M.

    2014-08-01

    Corrosion is a major problem in cooling water systems, which is often controlled using corrosion inhibitors. Solution hydrodynamics is one of the factors affecting corrosion inhibition of metals in these systems. The present work focuses on the study of the combined effects of citric acid concentration (as a green corrosion inhibitor) and fluid flow on corrosion of steel in simulated cooling water. Electrochemical techniques including Tafel polarization and electrochemical impedance spectroscopy were used for corrosion studies. Laminar flow was simulated using a rotating disk electrode. The effects of solution hydrodynamics on inhibition performance of citric acid were discussed. The citric acid showed low inhibition performance in quiescent solution; however, when the electrode rotated at 200 rpm, inhibition efficiency increased remarkably. It was attributed mainly to the acceleration of inhibitor mass transport toward metal surface. The efficiencies were then decreased at higher rotation speeds due to enhanced wall shear stresses on metal surface and separation of adsorbed inhibitor molecules. This article is first part of authors' attempts in designing green inhibitor formulations for industrial cooling water. Citric acid showed acceptable corrosion inhibition in low rotation rates; thus, it can be used as a green additive to the corrosion inhibitor formulations.

  2. Online analytical investigations on solvent-, temperature- and water vapour-induced phase transformations of citric acid

    Energy Technology Data Exchange (ETDEWEB)

    Helmdach, L.; Ulrich, J. [Martin-Luther-Universitaet Halle-Wittenberg, Zentrum fuer Ingenieurwissenschaft, Verfahrenstechnik/TVT, Halle (Saale) (Germany); Feth, M.P. [Sanofi-Aventis Deutschland GmbH, Chemical and Process Development Frankfurt Chemistry, Frankfurt (Germany)

    2012-09-15

    It was demonstrated exemplarily for the crystallization of citric acid that the usage of an ultrasound device as well as Raman spectroscopy enables the inline measurement and the control of phase transitions. The influence of different solvent compositions (water and ethanol-water) on the crystallization of citric acid was investigated. By increasing the ethanol content the transformation point was shifted towards higher temperatures. In addition, a strong impact on the nucleation point as well as on the crystal habit was detected in ethanol-water mixtures. The results lead to the assumption that a citric acid solvate exists, which is, however, highly unstable upon isolation from mother liquor and converts fast into the known anhydrate or monohydrate forms of citric acid. The presence of such a solvate, however, could not be proven during this study. Furthermore, factors such as temperature and humidity which might influence the phase transition of the solid product were analyzed by Hotstage-Raman Spectroscopy and Water Vapor Sorption Gravimetry-Dispersive Raman Spectroscopy. Both, temperature as well as humidity show a strong influence on the behaviour of CAM. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

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

    Science.gov (United States)

    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. The fate of Salmonella enteritidis PT4 in home-made mayonnaise prepared with citric acid.

    Science.gov (United States)

    Xiong, R; Xie, G; Edmondson, A S

    1999-01-01

    The fate of Salmonella enteritidis PT4 in home-made mayonnaise prepared with citric acid solution (citric acid concentration of > or = 4.98% (w/v)) was investigated. It was found that pH of mayonnaise is closely related to the ratio of egg yolk to citric acid, and the inactivation rate of the micro-organisms increases as the ratio decreases and/or incubation temperature increases. To achieve Salm. enteritidis PT4-free home-made mayonnaise prepared with pure lemon juice (citric acid concentration > or = 5% (w/v)), it is recommended that the pH should be 3.30 or below, or, in practice, at least 20 ml pure lemon juice per fresh egg yolk should be used. For the use of 20-35 ml pure lemon juice per egg yolk, the product should be held at 22 degrees C or over for at least 72 h and for the use of over 35 ml pure lemon juice per egg yolk, for at least 48 h before consumption or refrigeration.

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

    Science.gov (United States)

    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 (H2O2) was used to leach the metals from CPCB piece. The influence of system variables such as H2O2 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 H2O2 together in the leaching solution is essential for complete metal leaching. The optimum addition amount of H2O2 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.

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

    Science.gov (United States)

    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...

  7. Citric Acid Fuctionalized Magnetic Ferrite Nanoparticles for Photocatalytic Degradation of Azo Dye.

    Science.gov (United States)

    Mahto, Triveni Kumar; Roy, Anurag; Sahoo, Banalata; Sahu, Sumanta Kumar

    2015-01-01

    In this study different magnetic ferrite nanoparticles (MFe2O4, where M = Fe, Mn, Zn) were synthesized through an aqueous coprecipitation method and then functionalized with citric acid for the degradation of azo dye present in industrial waste water. Here we evaluated the role of citric acid for photocatalytic application. The synthesized nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and the catalytic activity in degradation of methyl orange (MO) was evaluated. The rate of MO degradation in different magnetic systems was determined by UV-Vis spectroscopy. The effect of active parameters (pH, initial MO concentration and effect of sunlight) on degradation performance was investigated. For the first time, citric acid chemistry is successfully exploited to develop a photocatalyst that can successfully degrade the dyes. This citric acid functionalized magnetic ferrite nanoparticles are very much effective for photocalytic degradation of dye and also these can be recollected with the help of permanent magnet for successive uses.

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

    Science.gov (United States)

    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…

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  11. Iron-dependent changes in cellular energy metabolism: influence on citric acid cycle and oxidative phosphorylation.

    Science.gov (United States)

    Oexle, H; Gnaiger, E; Weiss, G

    1999-11-10

    Iron modulates the expression of the critical citric acid cycle enzyme aconitase via a translational mechanism involving iron regulatory proteins. Thus, the present study was undertaken to investigate the consequences of iron perturbation on citric acid cycle activity, oxidative phosphorylation and mitochondrial respiration in the human cell line K-562. In agreement with previous data iron increases the activity of mitochondrial aconitase while it is reduced upon addition of the iron chelator desferrioxamine (DFO). Interestingly, iron also positively affects three other citric acid cycle enzymes, namely citrate synthase, isocitric dehydrogenase, and succinate dehydrogenase, while DFO decreases the activity of these enzymes. Consequently, iron supplementation results in increased formation of reducing equivalents (NADH) by the citric acid cycle, and thus in increased mitochondrial oxygen consumption and ATP formation via oxidative phosphorylation as shown herein. This in turn leads to downregulation of glucose utilization. In contrast, all these metabolic pathways are reduced upon iron depletion, and thus glycolysis and lactate formation are significantly increased in order to compensate for the decrease in ATP production via oxidative phosphorylation in the presence of DFO. Our results point to a complex interaction between iron homeostasis, oxygen supply and cellular energy metabolism in human cells.

  12. An overview of the properties of fatty acid alkyl esters

    Science.gov (United States)

    Fatty acid alkyl esters of plant oils, especially in the form of methyl esters, have numerous applications with fuel use having received the most attention in recent times due to the potential high volume. Various properties imparted by neat fatty acid alkyl esters have been shown to influence fuel ...

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    Mostafa, Yasser S; Alamri, Saad A

    2012-04-01

    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.

  15. High efficient treatment of citric acid effluent by Chlorella vulgaris and potential biomass utilization.

    Science.gov (United States)

    Li, Changling; Yang, Hailin; Xia, Xiaole; Li, Yuji; Chen, Luping; Zhang, Meng; Zhang, Ling; Wang, Wu

    2013-01-01

    The efficiency of treating citric acid effluent by green algae Chlorella was investigated. With the highest growth rate, Chlorella vulgaris C9-JN2010 that could efficiently remove nutrients in the citric acid effluent was selected for scale-up batch experiments under the optimal conditions, where its maximum biomass was 1.04 g l(-1) and removal efficiencies of nutrients (nitrogen, phosphorus, total organic carbon, chemical oxygen demand and biochemical oxygen demand) were above 90.0%. Algal lipid and protein contents were around 340.0 and 500.0 mg · g(-1) of the harvested biomass, respectively. Proportions of polyunsaturated fatty acids in the lipids and eight kinds of essential amino acids in algal protein were 74.0% and 40.0%, respectively. Three major fatty acids were hexadecanoic acid, eicosapentaenoic acid and docosadienoic acid. This specific effluent treatment process could be proposed as a dual-beneficial approach, which converts nutrients in the high strength citric acid effluent into profitable byproducts and reduces the contaminations.

  16. Affinity labelling enzymes with esters of aromatic sulfonic acids

    Science.gov (United States)

    Wong, Show-Chu; Shaw, Elliott

    1977-01-01

    Novel esters of aromatic sulfonic acids are disclosed. The specific esters are nitrophenyl p- and m-amidinophenylmethanesulfonate. Also disclosed is a method for specific inactivation of the enzyme, thrombin, employing nitrophenyl p-amidinophenylmethanesulfonate.

  17. EDTA and citric acid mediated phytoextraction of Zn, Cu, Pb and Cd through marigold (Tagetes erecta).

    Science.gov (United States)

    Sinhal, V K; Srivastava, Alok; Singh, V P

    2010-05-01

    Phytoextraction is an emerging cost-effective solution for remediation of contaminated soils which involves the removal of toxins, especially heavy metals and metalloids, by the roots of the plants with subsequent transport to aerial plant organs. The aim of the present investigation is to study the effects of EDTA and citric acid on accumulation potential of marigold (Tagetes erecta) to Zn, Cu, Pb, and Cd and also to evaluate the impacts of these chelators (EDTA and citric acid) in combination with all the four heavy metals on the growth of marigold. The plants were grown in pots and treated with Zn (7.3 mg l(-1)), Cu (7.5 mg I(-1)), Pb (3.7 mg l(-1)) and Cd (0.2 mg l(-1)) alone and in combination with different doses of EDTA i.e., 10, 20 and 30 mg l(-1). All the three doses of EDTA i.e., 10, 20 and 30 mg l(-1) significantly increased the accumulation of Zn, Cu, Pb and Cd by roots, stems and leaves as compared to control treatments. The 30 mg l(-1) concentration of citric acid showed reduced accumulation of these metals by root, stem and leaves as compared to lower doses i.e., 10 and 20 mg l(-1). Among the four heavy metals, Zn accumulated in the great amount (526.34 mg kg(-1) DW) followed by Cu (443.14 mg kg(-1) DW), Pb (393.16 mg kg(-1) DW) and Cd (333.62 mg kg(-1) DW) in leaves with 30 mg l(-1) EDTA treatment. The highest concentration of EDTA and citric acid (30 mg l(-1)) caused significant reduction in growth of marigold in terms of plant height, fresh weight of plant, total chlorophyll, carbohydrate content and protein content. Thus EDTA and citric acid efficiently increased the phytoextractability of marigold which can be used to remediate the soil contaminated with these metals.

  18. Engineering Yarrowia lipolytica for Enhanced Production of Lipid and Citric Acid

    Directory of Open Access Journals (Sweden)

    Ali Abghari

    2017-07-01

    Full Text Available Increasing demand for plant oil for food, feed, and fuel production has led to food-fuel competition, higher plant lipid cost, and more need for agricultural land. On the other hand, the growing global production of biodiesel has increased the production of glycerol as a by-product. Efficient utilization of this by-product can reduce biodiesel production costs. We engineered Yarrowia lipolytica (Y. lipolytica at various metabolic levels of lipid biosynthesis, degradation, and regulation for enhanced lipid and citric acid production. We used a one-step double gene knock-in and site-specific gene knock-out strategy. The resulting final strain combines the overexpression of homologous DGA1 and DGA2 in a POX-deleted background, and deletion of the SNF1 lipid regulator. This increased lipid and citric acid production in the strain under nitrogen-limiting conditions (C/N molar ratio of 60. The engineered strain constitutively accumulated lipid at a titer of more than 4.8 g/L with a lipid content of 53% of dry cell weight (DCW. The secreted citric acid reached a yield of 0.75 g/g (up to ~45 g/L from pure glycerol in 3 days of batch fermentation using a 1-L bioreactor. This yeast cell factory was capable of simultaneous lipid accumulation and citric acid secretion. It can be used in fed-batch or continuous bioprocessing for citric acid recovery from the supernatant, along with lipid extraction from the harvested biomass.

  19. Evaluation of the efficacy of 50% citric acid solution in plane wart treatment

    Directory of Open Access Journals (Sweden)

    Vali Anahita

    2007-01-01

    Full Text Available Background and Aims: Treatment of plane warts is problematic, methods such as cryotherapy and cauterization is associated with high recurrence rate, risk of scar, pain and high cost. Topical tretinoin causes irritant contact dermatitis that limited its use. Citric acid was used in treatment of warts in traditional medicine of Iran. We evaluated the efficacy of 50% citric acid solution in water in treatment of plane warts and compared it with 0.05% tretinoin lotion. Materials and Methods : This study was a double blind; prospective, case-control study.Seventy-five patients with bilateral plane warts who signed informed consent were included. Exclusion criteria were pregnancy, breast-feeding, suffering from any systemic disease and the use of any other drug due to treatment of warts in past six weeks. The patients randomly used citric acid or Tretinoin lotion to lesions at each side of the body. Randomization was performed by coin-flipping. Patients were examined at three weeks interval for six weeks and number of warts were recorded in the proforma, which included the name, sex, address and code of the drug that was used in each side of the body and side effects. The results were analyzed by Chi-square test statistically. Results: After six weeks 64.4% of the lesions in citric acid treated group disappeared versus 53.7% of the lesions in tretinoin treated group. This difference was significant ( P value Conclusion: On the basis of this study, the treatment of plane warts by 50% citric acid is strongly suggested. This modality is superior to tretinoin lotion due to higher efficacy and low incidence of side-effects and lower cost.

  20. CITRIC ACID AS A SET RETARDER FOR CALCIUM ALUMINATE PHOSPHATE CEMENTS.

    Energy Technology Data Exchange (ETDEWEB)

    SUGAMA,T.; BROTHERS, L.E.

    2005-01-01

    Citric acid added as set retarder significantly contributed to enhancing the setting temperature and to extending the thickening time of a calcium aluminate phosphate (CaP) geothermal cement slurry consisting of calcium aluminate cement (CAC) as the base reactant and sodium polyphosphate (NaP) solution as the acid reactant. The set-retarding activity of citric acid was due to the uptake of Ca{sup 2+} ions from the CAC by carboxylic acid groups within the citric acid. This uptake led to the precipitation of a Ca-complexed carboxylate compound as a set-retarding barrier layer on the CAC grains' surfaces. However, this barrier layer was vulnerable to disintegration by the attack of free Ca{sup 2+} ions from CAC, and also to degradation at elevated temperature, thereby promoting the generation of exothermic energy from acid-base reactions between the CAC and NaP after the barrier was broken. The exothermic reaction energy that was promoted in this way minimized the loss in strength of the citric acid-retarded cement. The phase composition assembled in both retarded and non-retarded cements after autoclaving at 180 C encompassed three reaction products, hydroxyapatite (HOAp), hydrogrossular and boehmite, which are responsible for strengthening the autoclaved cement. The first two reaction products were susceptible to reactions with sulfuric acid and sodium sulfate to form crystalline bassanite scale as the corrosion product. The boehmite phase possessed a great resistance to acid and sulfate. Although the bassanite scales clinging to the cement's surfaces were the major factor governing the loss in weight, they served in protecting the cement from further acid- and sulfate-corrosion until their spallation eventually occurred. Nevertheless, the repetitive processes of HOAp and hydrogrossular {yields} bassanite {yields} spallation played an important role in extending the useful lifetime of CaP cement in a low pH environment at 180 C.

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

    Science.gov (United States)

    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.

  2. Bioactive caffeic acid esters from Glycyrrhiza glabra.

    Science.gov (United States)

    Dey, Surajit; Deepak, Mundkinajeddu; Setty, Manjunath; D'Souza, Prashanth; Agarwal, Amit; Sangli, Gopal Krishna

    2009-01-01

    Thin layer chromatography bioautography (using DPPH spray reagent) guided fractionation of Glycyrrhiza glabra led to the isolation of two caffeic acid derivative esters, viz. eicosanyl caffeate (1) and docosyl caffeate (2). The two compounds exhibited potent elastase inhibitory activity, with IC(50) values of 0.99 microg mL(-1) and 1.4 microg mL(-1) for 1 and 2, respectively. The compounds also showed moderate antioxidant activity in DPPH and ABTS scavenging assays. The results indicate a possible role of caffeic acid derivatives, in addition to flavonoids in the anti-ulcer properties of G. glabra.

  3. Synthesis of Mesoporous, Nanocrystalline Lanthanum Phosphate in the Presence of Citric Acid and Stearic Acid

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Lanthanum phosphate was prepared in the presence of citric acid and stearic acid under methanolic conditions at pH 4.5 and pH 7, respectively.The samples obtained were intensively characterized using X-ray diffraction, nitrogen adsorption-desorption isotherm study, transmission electron microscopy (TEM), thermal gravimetric and differential thermal analysis, and Fourier transform infrared (FTIR) analysis .The as-synthesized samples prepared at pH 4.5 showed lamellar mesostructured form with high crystallinity.Results showed that the pore size and pore volume changed when the materials were prepared under different pH conditions.Morphology of the samples was observed by using TEM, which showed that the samples possessed relatively small particles closely packed together.The as-synthesized samples were investigated using FTIR, and the mesopore formation mechanism was discussed.

  4. Postharvest life of cut gerbera flowers as affected by salicylic acid and citric acid

    Directory of Open Access Journals (Sweden)

    H. Heidarnezhadian

    2017-03-01

    Full Text Available Effect of salicylic acid (SA combined with citric acid (CA on gerbera (Gerbera jamesonii cut flowers was studied. The study was conducted in a factorial arrangement, carried out in a complete randomized design. The factors were SA (0.5,1.5 and 3 mM and CA (1.5 and 3 mM. The effects of treatments on the total chlorophyll content, anthocyanin leakage and malondialdehyde content of cut flowers of gerbera were investigated. The results showed that the vase solution containing 1.5 mM SA significantly increased vase life compared to the control. In addition, the malondialdehyde accumulation reduced in the same solution while membrane stability was improved. Results suggest that SA increases vase life by affecting many of the age-related changes associated with Gerbera petal senescence.

  5. Kinetic modelling of the demineralization of shrimp exoskeleton using citric acid

    Directory of Open Access Journals (Sweden)

    Alewo Opuada AMEH

    2014-11-01

    Full Text Available Citric acid was used in the demineralization of shrimp exoskeleton and the kinetics of the demineralization process was studied. Kinetic data was obtained by demineralisation using five acid concentrations (0.1, 0.2, 0.3, 0.4 and 0.5M. The obtained kinetic data were fitted to the shrinking core model for fluid particle reactions. The concentration of calcium was found to decrease with time. For all acid concentrations considered, the best predictive mechanism for the demineralization process was determined to be Ash Layer Diffusion Control Mechanism. This was indicated by the high R2 values obtained (0.965 with 150% excess of citric acid.

  6. Influence of Benzotriazole on Corrosion Inhibition of Mild Steel in Citric Acid Medium

    OpenAIRE

    P. Matheswaran; A. K. Ramasamy

    2010-01-01

    Benzotriazole an organic compounds has been studied as corrosion inhibition for mild steel in 1 N citric acid by weight loss method. The result showed that the corrosion inhibition efficiency of the compound was found to be varying with the temperature and acid concentration. Also it was found that the corrosion inhibition behaviour of benzotriazole is better when the concentration of inhibitor is increased. The kinetic treatment of the results shows first order kinetics.

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

    Energy Technology Data Exchange (ETDEWEB)

    STALLINGS, MARY

    2004-07-08

    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 oxalic 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 untreated

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

    Science.gov (United States)

    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.

  9. Pioglitazone, quercetin and hydroxy citric acid effect on hepatic biomarkers in Non Alcoholic Steatohepatitis

    Directory of Open Access Journals (Sweden)

    Krishna Mohan Surapaneni

    2014-01-01

    Full Text Available Background: Non alcoholic steatohepatitis (NASH, severe form of diseases belonging to the spectrum of the Non alcoholic fatty liver disease (NAFLD. It is an asymptomatic disease which leads to fibrosis and finally to cirrhosis, an end stage liver disease. Objective: To study the effect of pioglitazone, quercetin and hydroxy citric acid on hepatic biomarkers and various biochemical parameters in experimentally induced non alcoholic steatohepatitis (NASH. Materials and Methods: Male Wister rats were divided into 8 groups. The activities of alkaline phosphatase (ALP, aspartate transaminase (AST, alanine transaminase (ALT, lactate dehydrogenase (LDH and γ-Glutamyl Transferase (GGT were assayed in serum. The levels of various other biochemical parameters such as serum albumin, total bilirubin, creatinine, urea, uric acid and glucose were also estimated in experimental NASH. Results: The NASH group produced severe liver injury by significantly increasing the serum levels of ALT, AST, GGT and LDH compared with that of the control. However, the experimental NASH rats treated with pioglitazone, with quercetin and with hydroxy citric acid showed an obvious decrease in ALT, AST, GGT and LDH levels when compared with that of NASH induced group. A significant increase in the levels of albumin, creatinine, urea, uric acid, glucose and total bilirubin was noticed in experimentally induced NASH group (group 2 when compared to rats in control group (group 1. Conclusion: It could be inferred from this study that, pioglitazone, quercetin and hydroxy citric acid may afford protection to the liver against NASH, as evidenced by the results of this study on the levels of various biochemical parameters such as glucose, urea, uric acid, creatinine and bilirubin. Whereas from the results of hepatic marker enzymes, it is evident that optimal protection was observed after quercetin treatment against experimental NASH whereas pioglitazone and hydroxy citric acid also

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

    Science.gov (United States)

    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.

  11. Effect of citric acid deamidation on in vitro digestibility and antioxidant properties of wheat gluten.

    Science.gov (United States)

    Qiu, Chaoying; Sun, Weizheng; Cui, Chun; Zhao, Mouming

    2013-12-01

    The effects of citric acid deamidation on the physiochemical properties of wheat gluten were investigated. In vitro digestion was carried out to determine changes of molecular weight distribution, amino acids composition and antioxidant efficacy of wheat gluten hydrolysates. Results indicated that citric acid deamidation significantly increased gluten solubility and surface hydrophobicity, at a neutral pH. Deamidation induced molecular weight distribution change of gluten with little proteolysis. Results from FTIR indicated that the α-helix and β-turn of deamidated gluten increased accompanied by a decrease of the β-sheet structure. After deamidation, in vitro pepsin digestibility of wheat gluten decreased, while in vitro pancreatin digestibility increased. The oxygen radical absorbance capacity (ORAC) activity of the in vitro digests decreased with increase of deamidation time. The high Lys and total essential AAs amounts in the final digests suggested that the nutritional values of wheat gluten after deamidation might be enhanced.

  12. Photochemical synthesis of citric acid cycle intermediates based on titanium dioxide.

    Science.gov (United States)

    Saladino, Raffaele; Brucato, John Robert; De Sio, Antonio; Botta, Giorgia; Pace, Emanuele; Gambicorti, Lisa

    2011-10-01

    The emergence of the citric acid cycle is one of the most remarkable occurrences with regard to understanding the origin and evolution of metabolic pathways. Although the chemical steps of the cycle are preserved intact throughout nature, diverse organisms make wide use of its chemistry, and in some cases organisms use only a selected portion of the cycle. However, the origins of this cycle would have arisen in the more primitive anaerobic organism or even back in the proto-metabolism, which likely arose spontaneously under favorable prebiotic chemical conditions. In this context, we report that UV irradiation of formamide in the presence of titanium dioxide afforded 6 of the 11 carboxylic acid intermediates of the reductive version of the citric acid cycle. Since this cycle is the central metabolic pathway of contemporary biology, this report highlights the role of photochemical processes in the origin of the metabolic apparatus.

  13. Chemical Synthesis and Functionalization of Cobalt Ferrite Nanoparticles with Oleic Acid and Citric Acid Encapsulation

    Directory of Open Access Journals (Sweden)

    Watawe Shrikant C.

    2015-01-01

    Full Text Available The functionalized nanoparticles have now a prime importance because of their wide ranging biomedical applications. The particles having size range 30nm-150nm are useful for cell wall interaction specifically the pinocytosis which takes place in all types of cells. The Cobalt ferrite nanoparticles have been synthesized using chemical co- precipitation route and the pH and temperature of the synthesis is controlled to obtain the optimum sized particles. The coating of Sodium Oleate and Citric acid was carried out in aqueous medium at room temperature. The characterization of coated and uncoated particles has been carried out using XRD and IR which confirm the ferrite structure formation. The TGA-DTA analysis shows the coating of magnetic particles. The SEM micrographs reveal the particle size, before and after coating to be in the range of 45 to 90 nm. The saturation magnetization is found to be 16.8 emu/gm.

  14. Reducing Heavy Metal Element from Coal Bottom Ash by Using Citric Acid Leaching Treatment

    Directory of Open Access Journals (Sweden)

    Yahya Ahmad Asyari

    2017-01-01

    Full Text Available Coal ash is the residue that is produced during coal combustion for instance fly ash, bottom ash or boiler slag which was primarily produced from the combustion of coal. With growth in coal burning power station, huge amount of coal bottom ash (CBA considered as hazardous material which are normally disposed in an on-site disposal system without any commercialization purpose. Previous researchers have studied the extraction of silica from agricultural wastes such as palm ash and rice husk ash (RHA and CBA by using leaching treatment method. In this study, the weaker acid, citric acid solution was used to replace the strong acid in leaching treatment process. Result showed that the heavy metal content such as Copper (Cu, Zinc (Zn and Lead (Pb can be decrease. Meanwhile the silica can be extracted up to 44% from coal bottom ash using citric acid leaching treatment under the optimum reaction time of 60 minutes with solution temperature of 60°C and concentration of citric acid more than 2%.

  15. Use of acetic and citric acids to control Salmonella Typhimurium in tahini (sesame paste).

    Science.gov (United States)

    Al-Nabulsi, Anas A; Olaimat, Amin N; Osaili, Tareq M; Shaker, Reyad R; Zein Elabedeen, Noor; Jaradat, Ziad W; Abushelaibi, Aisha; Holley, Richard A

    2014-09-01

    Since tahini and its products have been linked to Salmonella illness outbreaks and product recalls in recent years, this study assessed the ability of Salmonella Typhimurium to survive or grow in commercial tahini and when hydrated (10% w/v in water), treated with 0.1%-0.5% acetic or citric acids, and stored at 37, 21 and 10 °C for 28 d. S. Typhimurium survived in commercial tahini up to 28 d but was reduced in numbers from 1.7 to 3.3 log10 CFU/ml. However, in the moist or hydrated tahini, significant growth of S. Typhimurium occurred at the tested temperatures. Acetic and citric acids at ≤0.5% reduced S. Typhimurium by 2.7-4.8 log10 CFU/ml and 2.5-3.8 log10 CFU/ml, respectively, in commercial tahini at 28 d. In hydrated tahini the organic acids were more effective. S. Typhimurium cells were not detected in the presence of 0.5% acetic acid after 7 d or with 0.5% citric acid after 21 d at the tested temperatures. The ability of S. Typhimurium to grow or survive in commercial tahini and products containing hydrated tahini may contribute to salmonellosis outbreaks; however, use of acetic and citric acids in ready-to-eat foods prepared from tahini can significantly minimize the risk associated with this pathogen.

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

    Science.gov (United States)

    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.

  17. Methods of refining and producing isomerized fatty acid esters and fatty acids from natural oil feedstocks

    Energy Technology Data Exchange (ETDEWEB)

    Snead, Thomas E.; Cohen, Steven A.; Gildon, Demond L.; Beltran, Leslie V.; Kunz, Linda A.; Pals, Tessa M.; Quinn, Jordan R; Behrends, Jr., Raymond T.; Bernhardt, Randal J.

    2016-07-05

    Methods are provided for refining natural oil feedstocks and producing isomerized esters and acids. The methods comprise providing a C4-C18 unsaturated fatty ester or acid, and isomerizing the fatty acid ester or acid in the presence of heat or an isomerization catalyst to form an isomerized fatty ester or acid. In some embodiments, the methods comprise forming a dibasic ester or dibasic acid prior to the isomerizing step. In certain embodiments, the methods further comprise hydrolyzing the dibasic ester to form a dibasic acid. In certain embodiments, the olefin is formed by reacting the feedstock in the presence of a metathesis catalyst under conditions sufficient to form a metathesized product comprising olefins and esters, separating the olefins from the esters in the metathesized product, and transesterifying the esters in the presence of an alcohol to form a transesterified product having unsaturated esters.

  18. Viscosity controls humidity dependence of N2O5 uptake to citric acid aerosol

    Science.gov (United States)

    Gržinić, G.; Bartels-Rausch, T.; Berkemeier, T.; Türler, A.; Ammann, M.

    2015-12-01

    The heterogeneous loss of dinitrogen pentoxide (N2O5) to aerosol particles has a significant impact on the night-time nitrogen oxide cycle and therefore the oxidative capacity in the troposphere. Using a 13N short-lived radioactive tracer method, we studied the uptake kinetics of N2O5 on citric acid aerosol particles as a function of relative humidity (RH). The results show that citric acid exhibits lower reactivity than similar dicarboxylic and polycarboxylic acids, with uptake coefficients between ∼ 3 × 10-4-∼ 3 × 10-3 depending on humidity (17-70 % RH). At RH above 50 %, the magnitude and the humidity dependence can be best explained by the viscosity of citric acid as compared to aqueous solutions of simpler organic and inorganic solutes and the variation of viscosity with RH and, hence, diffusivity in the organic matrix. Since the diffusion rates of N2O5 in highly concentrated citric acid solutions are not well established, we present four different parameterizations of N2O5 diffusivity based on the available literature data or estimates for viscosity and diffusivity of H2O. Above 50 % RH, uptake is consistent with the reacto-diffusive kinetic regime whereas below 50 % RH, the uptake coefficient is higher than expected from hydrolysis of N2O5 within the bulk of the particles, and the uptake kinetics is most likely limited by loss on the surface only. This study demonstrates the impact of viscosity in highly oxidized and highly functionalized secondary organic aerosol material on the heterogeneous chemistry of N2O5 and may explain some of the unexpectedly low loss rates to aerosol derived from field studies.

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

    Science.gov (United States)

    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.

  20. Viscosity controls humidity dependence of N2O5 uptake to citric acid aerosol

    Directory of Open Access Journals (Sweden)

    G. Gržinić

    2015-08-01

    Full Text Available The heterogeneous loss of dinitrogen pentoxide (N2O5 to aerosol particles has a significant impact on the night time nitrogen oxide cycle and therefore the oxidative capacity in the troposphere. Using a 13N short lived radioactive tracer method we studied the uptake kinetics of N2O5 on citric acid aerosol particles as a function of relative humidity (RH. The results show that citric acid exhibits lower reactivity than similar di- and polycarboxylic acids, with uptake coefficients between ~ 3 × 10−4–~ 3 × 10−3 depending on humidity (17–70 % RH. This humidity dependence can be explained by a changing viscosity and, hence, diffusivity in the organic matrix. Since the viscosity of highly concentrated citric acid solutions is not well established, we present four different parameterizations of N2O5 diffusivity based on the available literature data or estimates for viscosity and diffusivity. Above 50 % RH, uptake is consistent with the reacto-diffusive kinetic regime whereas below 50 % RH, the uptake coefficient is higher than expected from hydrolysis of N2O5 within the bulk of the particles, and the uptake kinetics may be limited by loss on the surface only. This study demonstrates the impact of viscosity in highly oxidized and highly functionalized secondary organic aerosol material on the heterogeneous chemistry of N2O5 and may explain some of the unexpectedly low loss rates to aerosol derived from field studies.

  1. Effect of growing location, malaxation duration and citric acid treatment on the quality of olive oil.

    Science.gov (United States)

    Chih, HuiJun; James, Anthony P; Jayasena, Vijay; Dhaliwal, Satvinder S

    2013-04-01

    The total phenolic compounds of olive oil exert antiradical activity at cellular level and can prevent cardiovascular disease, metabolic syndrome and cancer. Increased awareness of its health benefits has increased the consumption of olive oil around the world. An alternative processing technique effective in increasing the amount of oil extracted while maintaining the oil quality is needed to meet the rising global demand for olive oil. Addition of 0.3 g mL(-1) citric acid at 1:1000 (v/w) to olive paste followed by a 30 min malaxation period significantly increased the oil recovery, concentration of total phenolic compounds and antiradical activity by 46.23, 120.27 and 31.48% respectively. While there was no significant effect on the acidity, the peroxide value was significantly reduced by 63.85%. The organoleptic characteristics of the olive oil extracted with citric acid were also comparable to those of the control. Addition of 0.3 g mL(-1) citric acid (i.e. 30% w/v) at 1:1000 (v/w) to olive paste followed by a 30 min malaxation period in a Blixer(®) 4.0 blender is the most promising extraction technique to improve the oil recovery, concentration of total phenolic compounds and antiradical activity of the extracted olive oil without compromising other quality parameters. © 2012 Society of Chemical Industry.

  2. Uranium Leaching from Contaminated Soil Utilizing Rhamnolipid, EDTA, and Citric Acid

    Directory of Open Access Journals (Sweden)

    Sara Asselin

    2014-01-01

    Full Text Available Biosurfactants have recently gained attention as “green” agents that can be used to enhance the remediation of heavy metals and some organic matter in contaminated soils. The overall objective of this paper was to investigate rhamnolipid, a microbial produced biosurfactant, and its ability to leach uranium present in contaminated soil from an abandoned mine site. Soil samples were collected from two locations in northern Arizona: Cameron (site of open pit mining and Leupp (control—no mining. The approach taken was to first determine the total uranium content in each soil using a hydrofluoric acid digestion, then comparing the amount of metal removed by rhamnolipid to other chelating agents EDTA and citric acid, and finally determining the amount of soluble metal in the soil matrix using a sequential extraction. Results suggested a complex system for metal removal from soil utilizing rhamnolipid. It was determined that rhamnolipid at a concentration of 150 μM was as effective as EDTA but not as effective as citric acid for the removal of soluble uranium. However, the rhamnolipid was only slightly better at removing uranium from the mining soil compared to a purified water control. Overall, this study demonstrated that rhamnolipid ability to remove uranium from contaminated soil is comparable to EDTA and to a lesser extent citric acid, but, for the soils investigated, it is not significantly better than a simple water wash.

  3. BUSINESS OPPORTUNITIES OF CITRIC ACID PRODUCTION BY FERMENTATION FROM SUGAR SUBSTRATES IN CUBA

    Directory of Open Access Journals (Sweden)

    Omar Pérez Navarro

    2016-04-01

    Full Text Available A proposal for opportunities of citric acid production in Cuba, using sources of sugar substrates such as refined sugar, molasses and whey, by submerged fermentation with Aspergillus niger, where a technology is established from the selected substrate which is provided and the microorganism used. This is a demanding process in terms of investment costs and operation where the best combinations of productivity and cost are achieved with molasses followed by refined sugar and whey. For the selected substrate, the mass and energy balance in each of the steps in the process of obtaining citric acid for different productive capacities of citric acid was made and the minimum economic size of 2.5 t / day was determined. A production capacity of 8 t / day of granulated acid (2 640 t / a, with estimated total investment of $ 9,068,713, NPV = $ 1,401,561, IRR = 27% and DPP = 3 years was selected. The project is resistant to the rising price of raw materials and the cost of electricity and is favored when the process is integrated into a sugar mill cogeneration, while it is sensitive to a reduction in the selling price of the product.

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

    Science.gov (United States)

    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.

  5. The effect of citric acid on the activity, thermodynamics and conformation of mushroom polyphenoloxidase.

    Science.gov (United States)

    Liu, Wei; Zou, Li-qiang; Liu, Jun-ping; Zhang, Zhao-qin; Liu, Cheng-mei; Liang, Rui-hong

    2013-09-01

    Few reports have focused on the effect of citric acid on thermodynamics and conformation of polyphenoloxidase (PPO). In this study, variations on activity, thermodynamics and conformation of mushroom PPO induced by citric acid (1-60mM) and relationships among these were investigated. It showed that with the increasing concentration of citric acid, the activity of PPO decreased gradually to an inactivity condition; inactivation rate constant (k) of PPO increased and the activation energy (Ea) as well as thermodynamic parameters (ΔG, ΔH, ΔS) decreased, which indicated that the thermosensitivity, stability and number of non-covalent bonds of PPO decreased. The conformation was gradually unfolded, which was reflected in the decrease of α-helix contents, increase of β-sheet and exposure of aromatic amino acid residuals. Moreover, two linear relationships of relative activities, enthalpies (ΔH) against α-helix contents were obtained. It indicated that changes of activity and thermodynamics might correlate to the unfolding of conformation.

  6. 蚕丝的柠檬酸脱胶%Degumming raw silk with citric acid

    Institute of Scientific and Technical Information of China (English)

    赵雯; 陈国强

    2012-01-01

    将柠檬酸用到蚕丝的脱胶处理中,研究了酸的质量浓度、反应温度和时间等对脱胶效果的影响,得出了最佳工艺:柠檬酸质量浓度15g/L,温度98℃,浴比1∶60,处理时间30min.研究了酸脱胶后蚕丝的机械性能和表面形态结构的变化,结果表明:对丝素的损伤较小,脱胶后丝的表面变得平滑.%Citric acid was used in silk degumming. The influences of acid concentration, temperature and time on the degumming were investigated. The optimum technological conditions were obtained: citric acid 15 g/L, 98 ℃ of degumming temperature, liquor ration 1:60, degumming time 30 min. The mechanical properties and surface morphology of degummed silk fiber were also investigated. The results showed that the citric acid degumming had little damage to silk fibroin, and the surface of degummed silk became smoother.

  7. 40 CFR 721.3110 - Polycarboxylic acid ester (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Polycarboxylic acid ester (generic... Substances § 721.3110 Polycarboxylic acid ester (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a polycarboxylic acid...

  8. 40 CFR 721.8660 - Propionic acid methyl ester (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Propionic acid methyl ester (generic... Substances § 721.8660 Propionic acid methyl ester (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a propionic acid methyl...

  9. Modeling and prediction of retardance in citric acid coated ferrofluid using artificial neural network

    Science.gov (United States)

    Lin, Jing-Fung; Sheu, Jer-Jia

    2016-06-01

    Citric acid coated (citrate-stabilized) magnetite (Fe3O4) magnetic nanoparticles have been conducted and applied in the biomedical fields. Using Taguchi-based measured retardances as the training data, an artificial neural network (ANN) model was developed for the prediction of retardance in citric acid (CA) coated ferrofluid (FF). According to the ANN simulation results in the training stage, the correlation coefficient between predicted retardances and measured retardances was found to be as high as 0.9999998. Based on the well-trained ANN model, the predicted retardance at excellent program from Taguchi method showed less error of 2.17% compared with a multiple regression (MR) analysis of statistical significance. Meanwhile, the parameter analysis at excellent program by the ANN model had the guiding significance to find out a possible program for the maximum retardance. It was concluded that the proposed ANN model had high ability for the prediction of retardance in CA coated FF.

  10. Some factors affecting on the behavior of steel electrode in citric acid solutions.

    Directory of Open Access Journals (Sweden)

    A.Diab

    2015-12-01

    Full Text Available Potential-time curves are constructed for the steel electrode in naturally aerated citric acid solutions devoid of and containing some aggressive and inhibitive compounds. Cl- and SO4 2- ions cause the destruction of passivity and initiation of pitting corrosion. The rate of oxide film growth by citric acid and oxide film destruction by Cl- and SO4 2- ions follows a direct logarithmic law as evident from the linear relationships between the open-circuit potential and the logarithm of immersion time. Urea, phenylhydrazine and 1,2-phenylenediamine compounds inhibit the pitting corrosion of steel. The rate of oxide film healing and thickening increases with their concentrations. In presence of constant inhibitor concentration, the efficiency of pitting inhibition increases in the order: (weak urea

  11. Citric acid-coated gold nanoparticles for visual colorimetric recognition of pesticide dimethoate

    Science.gov (United States)

    Dar, Aqib Iqbal; Walia, Shanka; Acharya, Amitabha

    2016-08-01

    A colorimetric chemo-sensor based on citric acid-coated gold NPs (C-GNP) showed a linear increase in fluorescence intensity with increasing concentration of pesticide dimethoate (DM). The limit of detection was found to be between 8.25± 0.3 and 20 ± 9.5 ppm. The increase in fluorescence intensity was suggested to have originated from the soft-soft interaction between C-GNPs and DM via sulfur group which is absent in pesticide dicofol (DF). Similar studies with citric acid-coated silver NPs (C-SNPs) did not result any change in the fluorescence intensity. The microscopic studies suggested aggregation of C-GNPs in the presence of DM but not in case of DF.

  12. A biodegradable thermoset polymer made by esterification of citric acid and glycerol.

    Science.gov (United States)

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

    2014-05-01

    A new biomaterial, a degradable thermoset polymer, was made from simple, economical, biocompatable monomers without the need for a catalyst. Glycerol and citric acid, nontoxic and renewable reagents, were crosslinked by a melt polymerization reaction at temperatures from 90 to 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 9 days.

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

    Science.gov (United States)

    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 (

  14. Biosynthetic and Bioenergetic Functions of Citric Acid Cycle Reactions in Rhodopseudomonas capsulata

    OpenAIRE

    Beatty, J. Thomas; Gest, Howard

    1981-01-01

    Rhodopseudomonas capsulata can grow in a number of alternative modes, including (i) photosynthetic, defined here as anaerobic growth with light as the energy source, and (ii) heterotrophic, referring to aerobic heterotrophic growth in darkness. The functions of citric acid cycle sequences in these growth modes were investigated using wild-type and appropriate mutant strains. Results of growth tests and O2 utilization experiments showed that in the heterotrophic mode, energy conversion is depe...

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

    Science.gov (United States)

    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.

  16. PHYTOCHEMICAL EVALUATION OF HYDROXY CITRIC ACID, CATECHINS AND CALCIUM PANTOTHENATE PRESENT IN HERBAL FORMULATION

    Directory of Open Access Journals (Sweden)

    S. P. Karuppiah

    2012-01-01

    Full Text Available The analytical method for the estimation of phytochemical active ingredients present in Garginia combogia extract, Green tea extract with calcium pantothenate for herbal formulations are evaluated for it’s Assay content and dissolution release. This herbal formulation with slim formula consists of several active ingredients such as Hydroxy Citric acid, catechins and calcium pantothenate. The HPLC method for the estimation of active content and the in-vitro dissolution release is developed for the study.

  17. Biosynthetic and Bioenergetic Functions of Citric Acid Cycle Reactions in Rhodopseudomonas capsulata

    OpenAIRE

    Beatty, J. Thomas; Gest, Howard

    1981-01-01

    Rhodopseudomonas capsulata can grow in a number of alternative modes, including (i) photosynthetic, defined here as anaerobic growth with light as the energy source, and (ii) heterotrophic, referring to aerobic heterotrophic growth in darkness. The functions of citric acid cycle sequences in these growth modes were investigated using wild-type and appropriate mutant strains. Results of growth tests and O2 utilization experiments showed that in the heterotrophic mode, energy conversion is depe...

  18. Effect of lactic, acetic and citric acids on quality changes of refrigerated green mussel, Perna viridis (Linnaeus, 1758

    Directory of Open Access Journals (Sweden)

    Payap Masniyom

    2007-07-01

    Full Text Available Effect of lactic, acetic and citric acids on the quality changes and shelf-life extension of green mussel stored at 4oC was investigated. The inhibitory effect on bacterial growth was pronounced when the concentration of lactic, acetic and citric acids increased (P<0.05. Green mussel dipped with lactic acid had the lower total volatile base, trimethylamine, ammonia and TCA-soluble peptides contents than those dipped in acetic and citric acids. However, the increases in exudates loss and cooking loss were observed in samples dipped in organic acids, causing the denaturation of muscle protein by acids used. Thiobarbituric acid reactive substances (TBARS increased as the organic acid concentration increased (P<0.05. Lactic acid dipped samples, particularly with 0.2 M, showed the greater acceptability than did those dipped in other acids throughout the storage of 27 days. The control sample had the acceptability only for 6 days of storage.

  19. Adsorption equilibrium of citric acid from supercritical carbon dioxide/ethanol on cyano column

    Institute of Scientific and Technical Information of China (English)

    Huisheng L; Guoqing Wang; Minhua Zhang; Zhongfeng Geng; Miao Yang; Yanpeng Sun

    2015-01-01

    Supercritical adsorption equilibrium has a significant role in defining supercritical adsorption behavior. In this paper, the adsorption equilibrium of citric acid from supercritical CO2/ethanol on a cyano column was systemat-ical y investigated with the elution by characteristic point method. Equilibrium loading was obtained at 313.15 K and 321.15 K with supercritical CO2/ethanol densities varying from 0.7068 g·cm−3 to 0.8019 g·cm−3. The exper-imental results showed that the adsorption capacity of citric acid decreased with increasing temperature and in-creasing density of the supercritical CO2/ethanol mobile phase. The adsorption equilibrium data were fitted wel by the Quadratic Hill isotherm model and the isotherms showed anti-Langmuir behavior. The monolayer satura-tion adsorption capacity of citric acid is in the range of 44.54 mg·cm−3 to 64.66 mg·cm−3 with an average value of 56.86 mg·cm−3.

  20. Inactivation of foot-and-mouth disease virus by citric acid and sodium carbonate with deicers.

    Science.gov (United States)

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

    2015-11-01

    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.

  1. Citric Acid Cycle Metabolites Predict the Severity of Myocardial Stunning and Mortality in Newborn Pigs.

    Science.gov (United States)

    Hyldebrandt, Janus Adler; Støttrup, Nicolaj Brejnholt; Frederiksen, Christian Alcaraz; Heiberg, Johan; Dupont Birkler, Rune Isak; Johannsen, Mogens; Schmidt, Michael Rahbek; Ravn, Hanne Berg

    2016-12-01

    Myocardial infarction and chronic heart failure induce specific metabolic changes in the neonatal myocardium that are closely correlated to outcome. The aim of this study was to examine the metabolic responses to noninfarct heart failure and inotropic treatments in the newborn heart, which so far are undetermined. A total of 28 newborn pigs were instrumented with a microdialysis catheter in the right ventricle, and intercellular citric acid cycle intermediates and adenosine metabolite concentrations were determined at 20-minute intervals. Stunning was induced by 10 cycles of 3 minutes of ischemia, which was performed by occluding the right coronary artery, followed by 3 minutes of reperfusion. Animals were randomized for treatment with epinephrine + milrinone, dopamine + milrinone, dobutamine, or saline. University hospital animal laboratory. Ischemia-reperfusion induced right ventricular stunning and increased the concentrations of pyruvate lactate, succinate, malate, hypoxanthine, and xanthine (all, p citric acid cycle intermediates and adenosine metabolites reflects the presence of myocardial stunning and predicts mortality in acute noninfarct right ventricular heart failure in newborn pigs. This phenomenon occurs independently of the type of inotrope, suggesting that citric acid cycle intermediates represent potential markers of acute noninfarct heart failure.

  2. Another unusual type of citric acid cycle enzyme in Helicobacter pylori: the malate:quinone oxidoreductase.

    Science.gov (United States)

    Kather, B; Stingl, K; van der Rest, M E; Altendorf, K; Molenaar, D

    2000-06-01

    The only enzyme of the citric acid cycle for which no open reading frame (ORF) was found in the Helicobacter pylori genome is the NAD-dependent malate dehydrogenase. Here, it is shown that in this organism the oxidation of malate to oxaloacetate is catalyzed by a malate:quinone oxidoreductase (MQO). This flavin adenine dinucleotide-dependent membrane-associated enzyme donates electrons to quinones of the electron transfer chain. Similar to succinate dehydrogenase, it is part of both the electron transfer chain and the citric acid cycle. MQO activity was demonstrated in isolated membranes of H. pylori. The enzyme is encoded by the ORF HP0086, which is shown by the fact that expression of the HP0086 sequence from a plasmid induces high MQO activity in mqo deletion mutants of Escherichia coli or Corynebacterium glutamicum. Furthermore, this plasmid was able to complement the phenotype of the C. glutamicum mqo deletion mutant. Interestingly, the protein predicted to be encoded by this ORF is only distantly related to known or postulated MQO sequences from other bacteria. The presence of an MQO shown here and the previously demonstrated presence of a 2-ketoglutarate:ferredoxin oxidoreductase and a succinyl-coenzyme A (CoA):acetoacetyl-CoA transferase indicate that H. pylori possesses a complete citric acid cycle, but one which deviates from the standard textbook example in three steps.

  3. In the aging housefly aconitase is the only citric acid cycle enzyme to decline significantly.

    Science.gov (United States)

    Yarian, Connie S; Sohal, Rajindar S

    2005-04-01

    The main objective of this study was to determine if the activities of the mitochondrial citric acid cycle enzymes are altered during the normal aging process. Flight muscle mitochondria of houseflies of different ages were used as a model system because of their apparent age-related decline in bioenergetic efficiency, evident as a failure of flying ability. The maximal activities of each of the citric acid cycle enzymes were determined in preparations of mitochondria from flies of relatively young, middle, and old age. Aconitase was the only enzyme exhibiting altered activity during aging. The maximal activity of aconitase from old flies was decreased by 44% compared to that from young flies while the other citric acid cycle enzymes showed no change in activity with age. It is suggested that the selective age-related decrease in aconitase activity is likely to contribute to a decline in the efficiency of mitochondrial bioenergetics, as well as result in secondary effects associated with accumulation of citrate and redox-active iron.

  4. Comparative bioavailability studies of citric acid and malonic acid based aspirin effervescent tablets

    Directory of Open Access Journals (Sweden)

    Anju Gauniya

    2010-01-01

    Full Text Available Purpose: The present investigation is aimed at comparing the pharmacokinetic profile (Bioavailability of aspirin in tablet formulations, which were prepared by using different effervescent excipients such as citric acid and malonic acid. Materials and Methods: The relative bioavailability and pharmacokinetics of citric acid based aspirin effervescent tablet (Product A and malonic acid based aspirin effervescent tablet (Product B formulations were evaluated for an in-vitro dissolution study and in-vivo bioavailability study, in 10 normal healthy rabbits. The study utilized a randomized, crossover design with a one-week washout period between doses. Blood samples were collected at 0, 1, 2, 4, 6, 8, 12 and 24 hours following a 100 mg/kg dose. Plasma samples were assayed by High Performance Liquid Chromatography. T max , C max , AUC 0-24 , AUC 0- ∞, MRT, K a, and relative bioavailability were estimated using the traditional pharmacokinetic methods and were compared by using the paired t-test. Result: In the present study, Products A and B showed their T max , C max , AUC 0-24 , AUC 0- ∞, MRT, and K a values as 2.5 h, 2589 ± 54.79 ng/ml, 9623 ± 112.87 ng.h/ml, 9586 ± 126.22 ng.h/ml, 3.6 ± 0.10 h, and 0.3698 ± 0.003 h -1 for Product A and 3.0 h, 2054 ± 55.79 ng/ml, 9637 ± 132.87 ng.h/ml, 9870 ± 129.22 ng.h/ml, 4.76 ± 0.10 h, and 0.3812 ± 0.002 h -1 for Product B, respectively. Conclusion: The results of the paired t-test of pharmacokinetics data showed that there was no significant difference between Products A and B. From both the in vitro dissolution studies and in vivo bioavailability studies it was concluded that products A and B had similar bioavailability.

  5. Cytotoxicity test of 40, 50 and 60% citric acid as dentin conditioner by using MTT assay on culture cell line

    Directory of Open Access Journals (Sweden)

    Christian Khoswanto

    2008-09-01

    Full Text Available Background: Open dentin is always covered by smear layer, therefore before restoration is performed, cavity or tooth which has been prepared should be clean from dirt. The researchers suggested that clean dentin surface would reach effective adhesion between resin and tooth structure, therefore dentin conditioner like citric acid was used to reach the condition. Even though citric acid is not strong acid but it can be very erosive to oral mucous. Several requirements should be fulfilled for dental product such as non toxic, non irritant, biocompatible and should not have negative effect against local, systemic or biological environment. Cytotoxicity test was apart of biomaterial evaluation and needed for standard screening. Purpose: This study was to know the cytotoxicity of 40, 50, 60% citric acid as dentin conditioner using MTT assay. Method: This study is an experimental research using the Post-Test Only Control Group Design. Six samples of each 40, 50 and 60% citric acid for citotoxicity test using MTT assay. The density of optic formazan indicated the number of living cells. All data were statistically analyzed by one way ANOVA. Result: The percentage of living cells in 40, 50 and 60% citric acid were 95.14%, 93.42% and 93.14%. Conclusion: Citric acid is non toxic and safe to be used as dentine conditioner.

  6. Changes in primary metabolism leading to citric acid overflow in Aspergillus niger.

    Science.gov (United States)

    Legisa, Matic; Mattey, Michael

    2007-02-01

    For citric acid-accumulating Aspergillus niger cells, the enhancement of anaplerotic reactions replenishing tricarboxylic acid cycle intermediates predisposes the cells to form the product. However, there is no increased citrate level in germinating spores and a complex sequence of developmental events is needed to change the metabolism in a way that leads to an increased level of tricarboxylic acid cycle intermediates in mycelia. A review of physiological events that cause such intracellular conditions, with the special emphasis on the discussion of hexose transport into the cells and regulation of primary metabolism, predominantly of glycolytic flux during the process, is presented.

  7. Adsorption and desorption dynamics of citric acid anions in soil

    KAUST Repository

    Oburger, E.

    2011-07-26

    The functional role of organic acid anions in soil has been intensively investigated, with special focus on (i) microbial respiration and soil carbon dynamics, (ii) nutrient solubilization or (iii) metal detoxification and reduction of plant metal uptake. Little is known about the interaction dynamics of organic acid anions with the soil matrix and the potential impact of adsorption and desorption processes on the functional significance of these effects. The aim of this study was to characterize experimentally the adsorption and desorption dynamics of organic acid anions in five agricultural soils differing in iron and aluminium oxide contents and using citrate as a model carboxylate. Results showed that both adsorption and desorption processes were fast in all soils, reaching a steady state within approximately 1 hour. However, for a given total soil citrate concentration (ct) the steady state was critically dependent on the starting conditions of the experiment, whether most of the citrate was initially present in solution (cl) or held on the solid phase (cs). Specifically, desorption-led processes resulted in significantly smaller steady-state solution concentrations than adsorption-led processes, indicating that hysteresis occurred. As it is not possible to distinguish between different adsorption and desorption pools in soil experimentally, a new dynamic hysteresis model that relies only on measured soil solution concentrations was developed. The model satisfactorily explained experimental data and was able to predict dynamic adsorption and desorption behaviour. To demonstrate its use, we applied the model to two relevant situations involving exudation and microbial degradation. The study highlighted the complex nature of citrate adsorption and desorption dynamics in soil. We conclude that existing models need to incorporate both temporal and hysteresis components to describe realistically the role and fate of organic acids in soil processes. © 2011 The

  8. Analysis of tellurium thin films electrodeposition from acidic citric bath

    Science.gov (United States)

    Kowalik, Remigiusz; Kutyła, Dawid; Mech, Krzysztof; Żabiński, Piotr

    2016-12-01

    This work presents the description of the electrochemical process of formation thin tellurium layers from citrate acidic solution. The suggested methodology consists in the preparation of stable acidic baths with high content of tellurium, and with the addition of citrate acid. In order to analyse the mechanism of the process of tellurium deposition, the electroanalytical tests were conducted. The tests of cyclic voltammetry and hydrodynamic ones were performed with the use of polycrystalline gold disk electrode. The range of potentials in which deposition of tellurium in direct four-electron process is possible was determined as well as the reduction of deposited Te° to Te2- and its re-deposition as a result of the comproportionation reaction. On the basis of the obtained results, the deposition of tellurium was conducted by the potentiostatic method. The influence of a deposition potential and a concentration of TeO2 in the solution on the rate of tellurium coatings deposition was examined. The presence of tellurium was confirmed by X-ray spectrofluorometry and electron probe microanalysis. In order to determine the phase composition and the morphology, the obtained coatings were analysed with the use of x-ray diffraction and scanning electron microscopy.

  9. Pd/C synthesized with citric acid: an efficient catalyst for hydrogen generation from formic acid/sodium formate.

    Science.gov (United States)

    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 H(2) 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.

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

    OpenAIRE

    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 appear...

  11. CITRIC ACID PRODUCTION BY WILD AND UV - TREATED STRAINS OF ASPERGILLUS NIGER ON TWO DIFFERENT MINERAL SALT MEDIA

    OpenAIRE

    Valentine Enyinna Anyanwu; Phillip O. Okerentugba

    2013-01-01

    Microbial production of citric acid by a novel Aspergillus niger EE-12 and its UV – treated strain (UV-1) were carried out in shake flask cultures using mineral salt media containing sucrose or fructose as the carbon and energy sources. The highest citric acid concentration (36.1g/l) was obtained with the UV – treated strain UV-1 after 144 hours in medium containing sucrose and this was significantly higher (p

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

    OpenAIRE

    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 appear...

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

    Science.gov (United States)

    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.

  14. Pyrolytic Behavior of Citric Acid%柠檬酸的热解特性

    Institute of Scientific and Technical Information of China (English)

    周顺; 徐迎波; 王程辉; 田振峰

    2011-01-01

    The pyrolytic behavior of citric acid was investigated by thermogravimetric system coupled to Fourier transform infrared spectrometer ( TG-FTIR). The TG curves, DTG curves, and relative contents of pyrolytic gas phase products of citric acid in oxygen of different concentrations were determined and compared. The formation rules of gas phase products and pyrolytic mechanism of citric acid were explored. The results showed that: 1) The main pyrolytic gas phase products of citric acid included C02, H20, CO, anhydride and ketone compounds, in which CO2 was the major, while CO was the minor, H20 emerged first, while anhydride the last. 2) There might exist two pyrolytic pathways, in one of the pathways citric acid was dehydrated and then decarbonated to form anhydride, and in the other to form ketones mainly by decarbonation. At the initial pyrolytic stage, both pathways coexisted, increasing oxygen concentration would benefit the formation of ketones. While at higher temperature, anhydride formation dominated.%使用热失重/傅里叶变换红外联用( TG-FTIR)技术研究了柠檬酸的热裂解特性,测定并比较了不同氧气浓度下柠檬酸的热重(TG)和微商热重(DTG)曲线,以及柠檬酸热解气相产物相对含量和生成规律,探讨了柠檬酸可能的热解机制.结果表明:①柠檬酸的热解气相产物主要有CO2,CO,H2O,酸酐和酮类物质.CO2是气相产物中相对含量最高的物质,CO最低;水最早出现在气相产物中,酸酐是最后存在于气相产物中的物质;②柠檬酸可能有2种主要热解途径:先脱水后脱CO2的酸酐生成模式和主要脱CO2的酮生成模式.在热解初期,2种模式同时发生,氧气浓度的增加有利于酮的生成.在较高温度下,主要以酸酐生成模式为主.

  15. Phenylpropanoid acid esters from Korean propolis and their antioxidant activities.

    Science.gov (United States)

    Lee, In-Kyoung; Han, Myung-Suk; Kim, Dae-Won; Yun, Bong-Sik

    2014-08-01

    Ten phenylpropanoic acid esters were isolated from an ethanolic extract of Korean propolis. Their structures were elucidated by spectroscopic methods including NMR and ESI-MS. Caffeic acid esters with catechol moiety exhibited significant ABTS and DPPH radical scavenging activity and protective effect against DNA damage by a Fenton reaction. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Phthalic acid esters found in municipal organic waste

    DEFF Research Database (Denmark)

    Hartmann, Hinrich; Ahring, Birgitte Kiær

    2003-01-01

    Contamination of the organic fraction of municipal solid waste (OFMSW) with xenobiotic compounds and their fate during anaerobic digestion was investigated. The phthalic acid ester di-(2- ethylhexyl)phthalate (DEHP) was identified as the main contaminant in OFMSW in concentrations more than half...... matter with high biogas yields and efficient reduction of the phthalic acid ester contamination....

  17. Aqueous citric acid as green reaction media for the synthesis of octahydroxanthenes

    Directory of Open Access Journals (Sweden)

    Camilo A. Navarro D.

    2013-08-01

    Full Text Available A simple, convenient and environmentally friendly one-pot procedure for the synthesis of 1,8-dioxo-octahydroxanthenes by the reaction of dimedone and aromatic aldehydes in aqueous citric acid is described. In this green synthetic protocol promoted by the reaction media, the use of any other catalysts and hazardous organic solvents are avoided, making the work up procedure greener and easier. The isolation of the products, obtained in good yields, is readily performed by filtration and crystallization from ethanol when required and the aqueous acidic media can be easily recycled and reused several times without significant loss of catalytic activity.

  18. The role of citric acid in oral peptide and protein formulations

    DEFF Research Database (Denmark)

    Welling, Søren H; Hubálek, František; Jacobsen, Jette;

    2014-01-01

    The excipient citric acid (CA) has been reported to improve oral absorption of peptides by different mechanisms. The balance between its related properties of calcium chelation and permeation enhancement compared to a proteolysis inhibition was examined. A predictive model of CA's calcium chelation...... not occur significantly at the acidic pH values where it effectively inhibits proteolysis, which is its dominant action in oral peptide formulations. On account of insulin's low basal permeability, inclusion of alternative permeation enhancers is likely to be necessary to achieve sufficient oral...

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

    Science.gov (United States)

    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.

  20. Lipid and citric acid production by wild yeasts grown in glycerol.

    Science.gov (United States)

    Souza, Karla Silva Teixeira; Schwan, Rosane Freitas; Dias, Disney Ribeiro

    2014-04-01

    In this study, crude glycerol was used as a carbon source in the cultivation of wild yeasts, aiming for the production of microbial lipids and citric acid. Forty yeasts of different sources were tested concerning their growth in crude and commercial glycerol. Four yeasts (Lidnera saturnus UFLA CES-Y677, Yarrowia lipolytica UFLA CM-Y9.4, Rhodotorula glutinis NCYC 2439, and Cryptococcus curvatus NCYC 476) were then selected owing to their ability to grow in pure (OD600 2.133, 1.633, 2.055, and 2.049, respectively) and crude (OD600 2.354, 1.753, 2.316, and 2.281, respectively) glycerol (10%, 20%, and 30%). Y. lipolytica UFLA CM-Y9.4 was selected for its ability to maintain cell viability in concentrations of 30% of crude glycerol, and high glycerol intake (18.907 g/l). This yeast was submitted to lipid production in 30 g/l of crude glycerol, and therefore obtained 63.4% of microbial lipids. In the fatty acid profile, there was a predominance of stearic (C18:0) and palmitic (C16:0) acids in the concentrations of 87.64% and 74.67%, respectively. We also performed optimization of the parameters for the production of citric acid, which yielded a production of 0.19 g/l of citric acid in optimum conditions (38.4 g/l of crude glycerol, agitation of 184 rpm, and temperature of 30°C). Yarrowia lipolytica UFLA CM-Y9.4 presented good lipid production when in the concentration of 30 g/l of glycerol. These data may be used for production in large quantities for the application of industrial biodiesel.

  1. Desorption of cadmium from a natural Shanghai clay using citric acid industrial wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Gu Yingying, E-mail: guyong99hg@yahoo.com.cn [Department of Environmental Science and Engineering, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), 66 West Changjiang Road, Qingdao 266555 (China); Yeung, Albert T., E-mail: yeungat@hku.hk [Department of Civil Engineering, The University of Hong Kong, Pokfulam Road (Hong Kong)

    2011-07-15

    Highlights: {yields} CAIW is very effective in desorbing cadmium from soil particle surfaces at soil mixture pHs of lower than 5. {yields} The cadmium desorption efficiency of CAIW also depends on the initial sorbed concentration of cadmium on soil particle surfaces. {yields} Complexions of cadmium with citric acid and acetic acid are the dominant mechanisms for cadmium desorption in the soil mixture pH range of 4-8. {yields} CAIW may be a promising enhancement agent for the remediation of heavy metal-contaminated soils. - Abstract: The sorption/desorption characteristics of heavy metals onto/from soil particle surfaces are the primary factors controlling the success of the remediation of heavy-metal contaminated soils. These characteristics are pH-dependent, chemical-specific, and reversible; and can be modified by enhancement agents such as chelates and surfactants. In this study, batch experiments were conducted to evaluate the feasibility of using citric acid industrial wastewater (CAIW) to desorb cadmium from a natural clay from Shanghai, China at different soil mixture pHs. It can be observed from the results that the proportion of cadmium desorbed from the soil using synthesized CAIW is generally satisfactory, i.e., >60%, when the soil mixture pH is lower than 6. However, the proportion of desorbed cadmium decreases significantly with increase in soil mixture pH. The dominant cadmium desorption mechanism using CAIW is the complexion of cadmium with citric acid and acetic acid in CAIW. It is concluded that CAIW can be a promising enhancement agent for the remediation of cadmium-contaminated natural soils when the environmental conditions are favorable. As a result, CAIW, a waste product itself, can be put into productive use in soil remediation.

  2. The relationship between fatty acid and citric acid concentrations in milk from Holstein cows uring the period of negative energy balance

    National Research Council Canada - National Science Library

    DUCHÁČEK, Jaromir; STÁDNÍK, Luděk; BERAN, Jan; OKROUHLÁ, Monika

    2012-01-01

    The objective of this study was to determine the relationship between body condition score changes and the dynamics of energy balance indicators - fatty acid and citric acid contents - in milk during...

  3. Use of ascorbic and citric acids to increase dialyzable iron from vinal (Prosopis ruscifolia) pulp.

    Science.gov (United States)

    Bernardi, C; Freyre, M; Sambucetti, M E; Pirovani, M E

    2004-01-01

    Vinal (Prosopis ruscifolia) is an ecologically important wild leguminous tree that grows spontaneously in Argentine deforested lands, the fruit of which is consumed by humans and animals. Because considerable iron content with low to intermediate availability has been previously reported in vinal pulps, its enhancement would be of interest. Iron availability was determined as iron dialyzability using an in vitro technique. Response surface methodology was used to evaluate iron availability increase after adding ascorbic and/or citric acids to vinal pulp at different mM acid/mM Fe ratios. Those ratios ranged from 0.05:1 to 9.95:1 and from 0.5:1 to 99.5:1 for ascorbic acid/Fe (AA:Fe) and citric acid/Fe (CA:Fe), respectively. The obtained second- and first-order polynomial equations showed that AA:Fe and CA:Fe molar ratios linear terms had a significant effect on iron dialyzability increase (P iron availability to a maximum of 4.6 times. Additional confirmatory experiments were made adding the same organic acids to different vinal pulps and to a traditional cake prepared with vinal pulp called "patay." There were no significant differences (p > 0.05) between predicted values obtained by the model and experimental results.

  4. Enhancing the functionality of biobased polyester coating resins through modification with citric acid.

    Science.gov (United States)

    Noordover, Bart A J; Duchateau, Robbert; van Benthem, Rolf A T M; Ming, Weihua; Koning, Cor E

    2007-12-01

    Citric acid (CA) was evaluated as a functionality-enhancing monomer in biobased polyesters suitable for coating applications. Model reactions of CA with several primary and secondary alcohols and diols, including the 1,4:3,6-dianhydrohexitols, revealed that titanium(IV) n-butoxide catalyzed esterification reactions involving these compounds proceed at relatively low temperatures, often via anhydride intermediates. Interestingly, the facile anhydride formation from CA at temperatures around CA's melting temperature ( T m = 153 degrees C) proved to be crucial in modifying sterically hindered secondary hydroxyl end groups. OH-functional polyesters were reacted with CA in the melt between 150 and 165 degrees C, yielding slightly branched carboxylic acid functional materials with strongly enhanced functionality. The acid/epoxy curing reaction of the acid-functional polymers was simulated with a monofunctional glycidyl ether. Finally, the CA-modified polyesters were applied as coatings, using conventional cross-linking agents. The formulations showed rapid curing, resulting in chemically and mechanically stable coatings. These results demonstrate that citric acid can be applied in a new way, making use of its anhydride formation to functionalize OH-functional polyesters, which is an important new step toward fully biobased coating systems.

  5. The effect of theobromine 200 mg/l topical gel exposure duration against surface enamel hardness resistance from 1% citric acid

    Science.gov (United States)

    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 enamel microhardness between different durations of exposure to theobromine gel and immersion in citric acid (p 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.

  6. Potential Application of Ascorbic Acid, Citric Acid and Oxalic Acid for Browning Inhibition in Fresh-Cut Fruits and Vegetables

    Directory of Open Access Journals (Sweden)

    Weerayuth SUTTIRAK

    2010-01-01

    Full Text Available The market for fresh-cut fruits and vegetables has grown rapidly in recent decades as a result of their freshness, convenience, and human health benefits. However, fresh fruits and vegetables deteriorate very rapidly after processing, especially cut-surface browning resulting from wound-induced physiological and biochemical changes. The application of antibrowning agents is one of the most effective methods for controlling the enzymatic browning reaction in fresh-cut fruits and vegetables. This article reviews the use of nature identical antibrowning agents, which are generally recognized as safe (GRAS including ascorbic acid, citric acid and oxalic acid for preventing browning in fresh-cut fruits and vegetables. Factors affecting inhibitory efficiency of the antibrowning agents and synergistic effects of the mixtures in various fresh-cut fruits and vegetables are presented.

  7. 40 CFR 721.10125 - Alkenedioic acid, dialkyl ester, reaction products with polyaminocarbomonocycle and alkenoic acid...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkenedioic acid, dialkyl ester, reaction products with polyaminocarbomonocycle and alkenoic acid alkyl ester (generic). 721.10125 Section... Substances § 721.10125 Alkenedioic acid, dialkyl ester, reaction products with polyaminocarbomonocycle...

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

    Science.gov (United States)

    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).

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

    Science.gov (United States)

    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.

  10. Expanding the modular ester fermentative pathways for combinatorial biosynthesis of esters from volatile organic acids.

    Science.gov (United States)

    Layton, Donovan S; Trinh, Cong T

    2016-08-01

    Volatile organic acids are byproducts of fermentative metabolism, for example, anaerobic digestion of lignocellulosic biomass or organic wastes, and are often times undesired inhibiting cell growth and reducing directed formation of the desired products. Here, we devised a general framework for upgrading these volatile organic acids to high-value esters that can be used as flavors, fragrances, solvents, and biofuels. This framework employs the acid-to-ester modules, consisting of an AAT (alcohol acyltransferase) plus ACT (acyl CoA transferase) submodule and an alcohol submodule, for co-fermentation of sugars and organic acids to acyl CoAs and alcohols to form a combinatorial library of esters. By assembling these modules with the engineered Escherichia coli modular chassis cell, we developed microbial manufacturing platforms to perform the following functions: (i) rapid in vivo screening of novel AATs for their catalytic activities; (ii) expanding combinatorial biosynthesis of unique fermentative esters; and (iii) upgrading volatile organic acids to esters using single or mixed cell cultures. To demonstrate this framework, we screened for a set of five unique and divergent AATs from multiple species, and were able to determine their novel activities as well as produce a library of 12 out of the 13 expected esters from co-fermentation of sugars and (C2-C6) volatile organic acids. We envision the developed framework to be valuable for in vivo characterization of a repertoire of not-well-characterized natural AATs, expanding the combinatorial biosynthesis of fermentative esters, and upgrading volatile organic acids to high-value esters. Biotechnol. Bioeng. 2016;113: 1764-1776. © 2016 Wiley Periodicals, Inc.

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

    Science.gov (United States)

    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

  12. Gene identification and functional analysis of methylcitrate synthase in citric acid-producing Aspergillus niger WU-2223L.

    Science.gov (United States)

    Kobayashi, Keiichi; Hattori, Takasumi; Honda, Yuki; Kirimura, Kohtaro

    2013-01-01

    Methylcitrate synthase (EC 2.3.3.5; MCS) is a key enzyme of the methylcitric acid cycle localized in the mitochondria of eukaryotic cells and related to propionic acid metabolism. In this study, cloning of the gene mcsA encoding MCS and heterologous expression of it in Escherichia coli were performed for functional analysis of the MCS of citric acid-producing Aspergillus niger WU-2223L. Only one copy of mcsA (1,495 bp) exists in the A. niger WU-2223L chromosome. It encodes a 51-kDa polypeptide consisting of 465 amino acids containing mitochondrial targeting signal peptides. Purified recombinant MCS showed not only MCS activity (27.6 U/mg) but also citrate synthase (EC 2.3.3.1; CS) activity (26.8 U/mg). For functional analysis of MCS, mcsA disruptant strain DMCS-1, derived from A. niger WU-2223L, was constructed. Although A. niger WU-2223L showed growth on propionate as sole carbon source, DMCS-1 showed no growth. These results suggest that MCS is an essential enzyme in propionic acid metabolism, and that the methylcitric acid cycle operates functionally in A. niger WU-2223L. To determine whether MCS makes a contribution to citric acid production, citric acid production tests on DMCS-1 were performed. The amount of citric acid produced from glucose consumed by DMCS-1 in citric acid production medium over 12 d of cultivation was on the same level to that by WU-2223L. Thus it was found that MCS made no contribution to citric acid production from glucose in A. niger WU-2223L, although MCS showed CS activity.

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

    Science.gov (United States)

    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.

  14. Biosynthesis of Citric Acid from Glycerol by Acetate Mutants of Yarrowia lipolytica in Fed-Batch Fermentation

    Directory of Open Access Journals (Sweden)

    Anita Rywińska

    2009-01-01

    Full Text Available Pure and crude glycerol from biodiesel production have been used as substrates for citric acid production by acetate-negative mutants of Yarrowia lipolytica in fed-batch fermentation. Both the final concentration and the yield of the product were the highest when Y. lipolytica Wratislavia AWG7 strain was used in the culture with pure or crude glycerol. With a medium containing 200 g/L of glycerol, production reached a maximum of citric acid of 139 g/L after 120 h. This high yield of the product (up to 0.69 g of citric acid per gram of glycerol consumed was achieved with both pure and crude glycerol. Lower yield of citric acid in the culture with Y. lipolytica Wratislavia K1 strain (about 0.45 g/g resulted from increased erythritol concentrations (up to 40 g/L, accumulated simultaneously with the citric acid. The concentration of isocitric acid, a by-product in this fermentation, was very low, in the range from 2.6 to 4.6 g/L.

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

    OpenAIRE

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

    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...

  16. Analysis of the citric acid cycle intermediates using gas chromatography-mass spectrometry.

    Science.gov (United States)

    Kombu, Rajan S; Brunengraber, Henri; Puchowicz, Michelle A

    2011-01-01

    Researchers view analysis of the citric acid cycle (CAC) intermediates as a metabolomic approach to identifying unexpected correlations between apparently related and unrelated pathways of metabolism. Relationships of the CAC intermediates, as measured by their concentrations and relative ratios, offer useful information to understanding interrelationships between the CAC and metabolic pathways under various physiological and pathological conditions. This chapter presents a relatively simple method that is sensitive for simultaneously measuring concentrations of CAC intermediates (relative and absolute) and other related intermediates of energy metabolism using gas chromatography-mass spectrometry.

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

    Science.gov (United States)

    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 (pO2) 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 pO2 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 pO2 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 pO2-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 pO2 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 dual

  18. Preparation of esters of gallic acid with higher primary alcohols

    NARCIS (Netherlands)

    Kerk, G.J.M. van der; Verbeek, J.H.; Cleton, J.C.F.

    1951-01-01

    The esters of gallic acid and higher primary alcohols, especially fatty alcohols, have recently gained considerable interest as possible antioxidants for fats. Two independent methods for the preparation of these esters are described. In the first method the hitherto unknown compound galloyl chlorid

  19. Evidence of a New Role for the High-Osmolarity Glycerol Mitogen-Activated Protein Kinase Pathway in Yeast: Regulating Adaptation to Citric Acid Stress†

    OpenAIRE

    Lawrence, Clare L.; Botting, Catherine H.; Antrobus, Robin; Coote, Peter J.

    2004-01-01

    Screening the Saccharomyces cerevisiae disruptome, profiling transcripts, and determining changes in protein expression have identified an important new role for the high-osmolarity glycerol (HOG) mitogen-activated protein kinase (MAPK) pathway in the regulation of adaptation to citric acid stress. Deletion of HOG1, SSK1, PBS2, PTC2, PTP2, and PTP3 resulted in sensitivity to citric acid. Furthermore, citric acid resulted in the dual phosphorylation, and thus activation, of Hog1p. Despite mino...

  20. Evidence of a New Role for the High-Osmolarity Glycerol Mitogen-Activated Protein Kinase Pathway in Yeast: Regulating Adaptation to Citric Acid Stress†

    OpenAIRE

    Lawrence, Clare L.; Botting, Catherine?H.; Antrobus, Robin; Coote, Peter J.

    2004-01-01

    Screening the Saccharomyces cerevisiae disruptome, profiling transcripts, and determining changes in protein expression have identified an important new role for the high-osmolarity glycerol (HOG) mitogen-activated protein kinase (MAPK) pathway in the regulation of adaptation to citric acid stress. Deletion of HOG1, SSK1, PBS2, PTC2, PTP2, and PTP3 resulted in sensitivity to citric acid. Furthermore, citric acid resulted in the dual phosphorylation, and thus activation, of Hog1p. Despite mino...

  1. Synthesis of cellulose by Acetobacter xylinum. VI. Growth on citric acid-cycle intermediates.

    Science.gov (United States)

    GROMET-ELHANAN, Z; HESTRIN, S

    1963-02-01

    Gromet-Elhanan, Zippora (The Hebrew University, Jerusalem, Israel) and Shlomo Hestrin. Synthesis of cellulose by Acetobacter xylinum. VI. Growth on citric acid-cycle intermediates. J. Bacteriol. 85:284-292. 1963.-Acetobacter xylinum could be made to grow on ethanol, acetate, succinate, or l-malate. The growth was accompanied by formation of opaque leathery pellicles on the surface of the growth medium. These pellicles were identified as cellulose on the basis of their chemical properties, solubility behavior, and infrared absorption spectra. Washed-cell suspensions prepared from cultures grown on ethanol or the organic acids, in contrast to washed sugar-grown cells, were able to transform citric-cycle intermediates into cellulose. The variations in the substrate spectrum of cellulose synthesis between sugar-grown cells and organic acids-grown cells were found to be correlated with differences in the oxidative capacity of the cells. The significance of the findings that A. xylinum could be made to grow on ethanol on complex as well as synthetic media is discussed from the viewpoint of the whole pattern of Acetobacter classification.

  2. Characterization and functional properties of mango peel pectin extracted by ultrasound assisted citric acid.

    Science.gov (United States)

    Wang, Miaomiao; Huang, Bohui; Fan, Chuanhui; Zhao, Kaili; Hu, Hao; Xu, Xiaoyun; Pan, Siyi; Liu, Fengxia

    2016-10-01

    Pectin was extracted from 'Tainong No. 1' mango peels, using a chelating agent-citric acid as extraction medium by ultrasound-assisted extraction (UAE) and conventional extraction (CE) at temperatures of 20 and 80°C. Chemical structures, rheological and emulsifying properties of mango peel pectins (MPPs) were comparatively studied with laboratory grade citrus pectin (CP). All MPPs exhibited higher protein content (4.74%-5.94%), degree of methoxylation (85.43-88.38%), average molecular weight (Mw, 378.4-2858kDa) than the CP, but lower galacuronic acid content (GalA, 52.21-53.35%). CE or UAE at 80°C resulted in significantly higher pectin yield than those at 20°C, while the extraction time for UAE-80°C (15min) was significantly shorter compared to CE-80°C (2h) with comparable pectin yield. Moreover, MPPs extracted at 80°C were observed with higher GalA and protein content, higher Mw, resulting in higher viscosity, better emulsifying capacity and stability, as compared to those extracted at 20°C and the CP. Therefore, these results suggested that MPPs from 'Tainong No. 1' may become a highly promising pectin with good thickening and emulsifying properties, using ultrasound-assisted citric acid as an efficient and eco-friendly extraction method.

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

    Energy Technology Data Exchange (ETDEWEB)

    Seol, Yongkoo; Javandel, Iraj

    2008-03-15

    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 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.

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

    Directory of Open Access Journals (Sweden)

    Rodrigo Cavassim

    2012-06-01

    Full Text Available OBJECTIVES: 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.

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

    Science.gov (United States)

    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.

  6. Citric acid and sodium citrate effects on pink color development of cooked ground turkey irradiated pre- and post-cooking.

    Science.gov (United States)

    Sammel, L M; Claus, J R

    2006-03-01

    The effects of citric acid (0.15%, 0.3%) and sodium citrate (0.5%, 1.0%) on pink color development in ground turkey following irradiation (0, 2.5, 5.0kGy) were examined. Citric acid and sodium citrate had little effect on pink color when samples were irradiated prior to cooking. In contrast, when samples were cooked prior to irradiation, citric acid (0.3%) and sodium citrate (1.0%) reduced redness as indicated by eliminating a reflectance minimum at approximately 571nm, lessening greater reflectance in the red wavelength region, and preventing greater reducing conditions caused by irradiation. Citric acid significantly reduced pH and yields whereas sodium citrate reduced pH and yields to a lesser extent. Both citric acid and sodium citrate are potential ingredients that can be added during processing to prevent undesirable pink color in precooked irradiated ground turkey and therefore can result in greater acceptance of irradiated products by consumers.

  7. Effects of uncoated and citric acid coated cerium oxide nanoparticles, bulk cerium oxide, cerium acetate, and citric acid on tomato plants.

    Science.gov (United States)

    Barrios, Ana Cecilia; Rico, Cyren M; Trujillo-Reyes, Jesica; Medina-Velo, Illya A; Peralta-Videa, Jose R; Gardea-Torresdey, Jorge L

    2016-09-01

    Little is known about the physiological and biochemical responses of plants exposed to surface modified nanomaterials. In this study, tomato (Solanum lycopersicum L.) plants were cultivated for 210days in potting soil amended with uncoated and citric acid coated cerium oxide nanoparticles (nCeO2, CA+nCeO2) bulk cerium oxide (bCeO2), and cerium acetate (CeAc). Millipore water (MPW), and citric acid (CA) were used as controls. Physiological and biochemical parameters were measured. At 500mg/kg, both the uncoated and CA+nCeO2 increased shoot length by ~9 and ~13%, respectively, while bCeO2 and CeAc decreased shoot length by ~48 and ~26%, respectively, compared with MPW (p≤0.05). Total chlorophyll, chlo-a, and chlo-b were significantly increased by CA+nCeO2 at 250mg/kg, but reduced by bCeO2 at 62.5mg/kg, compared with MPW. At 250 and 500mg/kg, nCeO2 increased Ce in roots by 10 and 7 times, compared to CA+nCeO2, but none of the treatments affected the Ce concentration in above ground tissues. Neither nCeO2 nor CA+nCeO2 affected the homeostasis of nutrient elements in roots, stems, and leaves or catalase and ascorbate peroxidase in leaves. CeAc at 62.5 and 125mg/kg increased B (81%) and Fe (174%) in roots, while at 250 and 500mg/kg, increased Ca in stems (84% and 86%, respectively). On the other hand, bCeO2 at 62.5 increased Zn (152%) but reduced P (80%) in stems. Only nCeO2 at 62.5mg/kg produced higher total number of tomatoes, compared with control and the rest of the treatments. The surface coating reduced Ce uptake by roots but did not affect its translocation to the aboveground organs. In addition, there was no clear effect of surface coating on fruit production. To our knowledge, this is the first study comparing the effects of coated and uncoated nCeO2 on tomato plants. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. 40 CFR 721.6200 - Fatty acid polyamine condensate, phosphoric acid ester salts.

    Science.gov (United States)

    2010-07-01

    ..., phosphoric acid ester salts. 721.6200 Section 721.6200 Protection of Environment ENVIRONMENTAL PROTECTION... ester salts. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substances identified as fatty acid polyamine condensate, phosphate ester salts (PMNs P-90-1984 and...

  9. Protonation Equilibria of L-Aspartic, Citric and Succinic Acids in Anionic Micellar Media

    Directory of Open Access Journals (Sweden)

    P. Srinivasa Rao

    2009-01-01

    Full Text Available The impact of sodium lauryl sulphate (SLS on the protonation equilibria of L-aspartic acid, citric acid and succinic acid has been studied in various concentrations (0.5-2.5% w/v of SLS solution maintaining an ionic strength of 0.16 mol dm-3 at 303 K. The protonation constants have been calculated with the computer program MINIQUAD75 and the best fit models have been calculated based on statistical parameters. The trend of log values of step-wise protonation constants with mole fraction of the medium has been explained based on electrostatic and non-electrostatic forces operating on the protonation equilibria. The effects of errors on the protonation constants have also been presented.

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

    Directory of Open Access Journals (Sweden)

    Cristina Berthold Sperandio

    2008-02-01

    Full Text Available 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.

  11. Modeling and prediction of retardance in citric acid coated ferrofluid using artificial neural network

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Jing-Fung, E-mail: jacklin@cc.feu.edu.tw [Department of Industrial Design, Far East University, Taiwan, ROC (China); Sheu, Jer-Jia [Department of Mechanical Engineering, Southern Taiwan University of Science and Technology, Taiwan, ROC (China)

    2016-06-01

    Citric acid coated (citrate-stabilized) magnetite (Fe{sub 3}O{sub 4}) magnetic nanoparticles have been conducted and applied in the biomedical fields. Using Taguchi-based measured retardances as the training data, an artificial neural network (ANN) model was developed for the prediction of retardance in citric acid (CA) coated ferrofluid (FF). According to the ANN simulation results in the training stage, the correlation coefficient between predicted retardances and measured retardances was found to be as high as 0.9999998. Based on the well-trained ANN model, the predicted retardance at excellent program from Taguchi method showed less error of 2.17% compared with a multiple regression (MR) analysis of statistical significance. Meanwhile, the parameter analysis at excellent program by the ANN model had the guiding significance to find out a possible program for the maximum retardance. It was concluded that the proposed ANN model had high ability for the prediction of retardance in CA coated FF. - Highlights: • The feedforward ANN is applied for modeling of retardance in CA coated FFs. • ANN can predict the retardance at excellent program with acceptable error to MR. • The proposed ANN has high ability for the prediction of retardance.

  12. HYDRATION CHARACTERISTICS OF PROMPT CEMENT IN THE PRESENCE CITRIC ACID AS RETARDER

    Directory of Open Access Journals (Sweden)

    Mohamed Heikal

    2015-03-01

    Full Text Available The aim of the present work is to study the influence of citric acid (CA as retarder on the properties of prompt cement pastes. The dosages of CA were 0.50, and 0.75, 1.00 and 1.25 mass % of prompt cement. The initial and final setting times, bulk density, compressive strength, total porosity, and hydration kinetics such as free lime, combined water contents and XRD for selected sample were investigated. The results obtained in this study showed that the addition of CA elongates the initial and final setting times and decreases the compressive strength and combined water contents, whereas, it increases the total porosity at all ages of hydration. CA retards the liberation of Ca(OH2 of prompt pastes. The free lime contents of prompt cement pastes are slightly increased up to 28 days then sharply increased up to 90 days. Thus, it is suggested that citrate sorbed onto the clinker surface and formed a protective layer around the clinker grains retarding their dissolution. The sharp increase of compressive strength at later ages after 28 days up to 90 days. The presence of 0.75 mass % citric acid achieves the initial and final setting time of the prompt cement according to the ASTM specification.

  13. General synthesis of sponge-like ultrafine nanoporous metals by dealloying in citric acid

    Institute of Scientific and Technical Information of China (English)

    Hongjie Xu; Shujie Pang; Yu Jin; Tao Zhang

    2016-01-01

    A general method is proposed to synthesize ultrafine nanoporous Cu,Ag,and Ni with novel sponge-like morphologies,high porosities,and large surface areas.The materials are produced by dealloying Mg65M25Y10 (M =Cu,Ag,and Ni) metallic glasses in citric acid.Citric acid played a key role due to its capping effect,which reduced the surface diffusion of metals.A structural model consistent with the sponge-like morphology was constructed to calculate the porosity and the surface area.The mechanism of the dealloying process in dtric add,involving ligament formation and coarsening,was illustrated.The mechanism was capable of explaining the experimental trends of dealloying,especially the morphology.A glucose sensor,which can be further developed into a high-precision real-time glucose monitor for medical use,was constructed using sponge-like nanoporous copper.Our findings are not only relevant to understanding the dealloying mechanism of metallic glasses,but also provide promising materials for multiple applications.

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

    Energy Technology Data Exchange (ETDEWEB)

    Nuryadin, Bebeh W.; Pratiwi, Tripuspita; Faryuni, Irfana D.; Iskandar, Ferry, E-mail: ferry@fi.itb.ac.id; Abdullah, Mikrajuddin; Khairurrijal [Department of Physics, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Ganesha 10 Bandung, Indonesia 40132 (Indonesia); Ogi, Takashi; Okuyama, Kikuo [Department of Chemical Engineering, Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi Hiroshima, Japan 739-8527 (Japan)

    2015-04-16

    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 by 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.

  15. Reconsideration of the significance of substrate-level phosphorylation in the citric acid cycle*.

    Science.gov (United States)

    Lambeth, David O

    2006-01-01

    For nearly 50 years, students of metabolism in animals have been taught that a substrate-level phosphorylation in the Krebs citric acid cycle produces GTP that subsequently undergoes a transphosphorylation with ADP catalyzed by nucleoside diphosphate kinase. Research in the past decade has revealed that animals also express an ADP-forming succinate-CoA ligase whose activity exceeds that of the GDP-forming enzyme in some tissues. Here I argue that the primary fate of GTP is unlikely to be transphosphorylation with ADP. Rather, two succinate-CoA ligases with different nucleotide specificities have evolved to better integrate and regulate the central metabolic pathways that involve the citric acid cycle. The products of substrate-level phosphorylation, ATP and/or GTP, may represent a pool of nucleotide that has a different phosphorylation potential than the ATP made by oxidative phosphorylation and may be channeled to meet specific needs within mitochondria and the cell. Further research is needed to determine the applicable mechanisms and how they vary in tissues. Copyright © 2006 International Union of Biochemistry and Molecular Biology, Inc.

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

    Science.gov (United States)

    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. Rare linking hydrogels based on acrylic acid and carbohydrate esters

    Directory of Open Access Journals (Sweden)

    U. Akhmedov

    2012-09-01

    Full Text Available The process of copolymerization of acrylic acid and esters poliallil sucrose; pentaerythritol and sorbitol, some of its laws are identified. The kinetic regularities of copolymerization and the optimum conditions of synthesis was established.

  18. Inert Reassessment Document for PEG Fatty Acid Esters

    Science.gov (United States)

    The tolerance reassessment decision document and action memorandum for the PEG fatty acid ester date September 28, 2005, included two tolerance exemptions (under 40 CFR 180.910 and $) CFR 180.930, respectively)

  19. Evidence of a New Role for the High-Osmolarity Glycerol Mitogen-Activated Protein Kinase Pathway in Yeast: Regulating Adaptation to Citric Acid Stress†

    Science.gov (United States)

    Lawrence, Clare L.; Botting, Catherine H.; Antrobus, Robin; Coote, Peter J.

    2004-01-01

    Screening the Saccharomyces cerevisiae disruptome, profiling transcripts, and determining changes in protein expression have identified an important new role for the high-osmolarity glycerol (HOG) mitogen-activated protein kinase (MAPK) pathway in the regulation of adaptation to citric acid stress. Deletion of HOG1, SSK1, PBS2, PTC2, PTP2, and PTP3 resulted in sensitivity to citric acid. Furthermore, citric acid resulted in the dual phosphorylation, and thus activation, of Hog1p. Despite minor activation of glycerol biosynthesis, the inhibitory effect of citric acid was not due to an osmotic shock. HOG1 negatively regulated the expression of a number of proteins in response to citric acid stress, including Bmh1p. Evidence suggests that BMH1 is induced by citric acid to counteract the effect of amino acid starvation. In addition, deletion of BMH2 rendered cells sensitive to citric acid. Deletion of the transcription factor MSN4, which is known to be regulated by Bmh1p and Hog1p, had a similar effect. HOG1 was also required for citric acid-induced up-regulation of Ssa1p and Eno2p. To counteract the cation chelating activity of citric acid, the plasma membrane Ca2+ channel, CCH1, and a functional vacuolar membrane H+-ATPase were found to be essential for optimal adaptation. Also, the transcriptional regulator CYC8, which mediates glucose derepression, was required for adaptation to citric acid to allow cells to metabolize excess citrate via the tricarboxylic acid (TCA) cycle. Supporting this, Mdh1p and Idh1p, both TCA cycle enzymes, were up-regulated in response to citric acid. PMID:15060153

  20. Evidence of a new role for the high-osmolarity glycerol mitogen-activated protein kinase pathway in yeast: regulating adaptation to citric acid stress.

    Science.gov (United States)

    Lawrence, Clare L; Botting, Catherine H; Antrobus, Robin; Coote, Peter J

    2004-04-01

    Screening the Saccharomyces cerevisiae disruptome, profiling transcripts, and determining changes in protein expression have identified an important new role for the high-osmolarity glycerol (HOG) mitogen-activated protein kinase (MAPK) pathway in the regulation of adaptation to citric acid stress. Deletion of HOG1, SSK1, PBS2, PTC2, PTP2, and PTP3 resulted in sensitivity to citric acid. Furthermore, citric acid resulted in the dual phosphorylation, and thus activation, of Hog1p. Despite minor activation of glycerol biosynthesis, the inhibitory effect of citric acid was not due to an osmotic shock. HOG1 negatively regulated the expression of a number of proteins in response to citric acid stress, including Bmh1p. Evidence suggests that BMH1 is induced by citric acid to counteract the effect of amino acid starvation. In addition, deletion of BMH2 rendered cells sensitive to citric acid. Deletion of the transcription factor MSN4, which is known to be regulated by Bmh1p and Hog1p, had a similar effect. HOG1 was also required for citric acid-induced up-regulation of Ssa1p and Eno2p. To counteract the cation chelating activity of citric acid, the plasma membrane Ca(2+) channel, CCH1, and a functional vacuolar membrane H(+)-ATPase were found to be essential for optimal adaptation. Also, the transcriptional regulator CYC8, which mediates glucose derepression, was required for adaptation to citric acid to allow cells to metabolize excess citrate via the tricarboxylic acid (TCA) cycle. Supporting this, Mdh1p and Idh1p, both TCA cycle enzymes, were up-regulated in response to citric acid.

  1. Triterpene hexahydroxydiphenoyl esters and a quinic acid purpurogallin carbonyl ester from the leaves of Castanopsis fissa.

    Science.gov (United States)

    Huang, Yong-Lin; Tsujita, Takaaki; Tanaka, Takashi; Matsuo, Yosuke; Kouno, Isao; Li, Dian-Peng; Nonaka, Gen-ichiro

    2011-11-01

    Triterpene hexahydroxydiphenoyl (HHDP) esters have only been isolated from Castanopsis species, and the distribution of these esters in nature is of chemotaxonomical interest. In this study, the chemical constituents of the leaves of Castanopsis fissa were examined in detail to identify and isolate potential HHDP esters. Together with 53 known compounds, 3,4-di-O-galloyl-1-O-purpurogallin carbonyl quinic acid (1) and 3,24-(S)-HHDP-2α,3β,23,24-tetrahydroxytaraxastan-28,20β-olide (2) were isolated and their structures were elucidated by spectroscopic and chemical methods. The polyphenols of the leaves were mainly composed of galloyl quinic acids, triterpenes HHDP esters, ellagitannins and flavonol glycosides. In particular, the isolation yields of 1,3,4-trigalloyl quinic acid and compound 2 were 1.53% and 0.27%, respectively, from the fresh leaves. The presence of lipid soluble HHDP esters of oleanane-type triterpenes as one of the major metabolites is an important chemotaxonomical discovery. Lipase inhibition activities and ORAC values of the major constituents were compared. The triterpene HHDP ester showed moderate lipase inhibition activity and myricitrin gave the largest ORAC value.

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

    Science.gov (United States)

    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.

  3. Citric Acid Monohydrate Production Process of Research%一水柠檬酸生产工艺研究

    Institute of Scientific and Technical Information of China (English)

    杨克林

    2016-01-01

    文章首先阐述了一水柠檬酸的用途,常规的生产方法,以及存在的问题。然后针对一水柠檬酸生产过程中的结晶、分离和烘干三道关键工序进行研究分析,最后得出较为理想的一水柠檬酸生产工艺。%The paper first describes the use of a water citric acid,conventional production methods,as well as the existing problems.Then the three key processes of crystallization,separation and drying in the production of citric acid were studied and analyzed.Finally,the ideal water citric acid production process was obtained.

  4. 77 FR 74171 - Citric Acid and Certain Citrate Salts From the People's Republic of China: Final Results of...

    Science.gov (United States)

    2012-12-13

    ... sodium citrate, otherwise known as citric acid sodium salt, and the monohydrate and monopotassium forms of potassium citrate.\\5\\ Sodium citrate also includes both trisodium citrate and monosodium citrate... acid and sodium citrate are classifiable under 2918.14.0000 and 2918.15.1000 of the Harmonized...

  5. Ketogenesis in isolated rat liver mitochondria I. Relationships with the citric acid cycle and with the mitochondrial energy state

    NARCIS (Netherlands)

    Lopes-Cardozo, M.; Bergh, S.G. van den

    1972-01-01

    1. A method is described to calculate the distribution of acetyl-CoA over the citric acid cycle and ketogenesis during the oxidation of fatty acids in the presence of added malate. 2. Increasing concentrations of added Krebs cycle intermediates lower the rate of ketogenesis both in the low-energy

  6. Fatty acid phytyl ester synthesis in chloroplasts of Arabidopsis.

    Science.gov (United States)

    Lippold, Felix; vom Dorp, Katharina; Abraham, Marion; Hölzl, Georg; Wewer, Vera; Yilmaz, Jenny Lindberg; Lager, Ida; Montandon, Cyrille; Besagni, Céline; Kessler, Felix; Stymne, Sten; Dörmann, Peter

    2012-05-01

    During stress or senescence, thylakoid membranes in chloroplasts are disintegrated, and chlorophyll and galactolipid are broken down, resulting in the accumulation of toxic intermediates, i.e., tetrapyrroles, free phytol, and free fatty acids. Chlorophyll degradation has been studied in detail, but the catabolic pathways for phytol and fatty acids remain unclear. A large proportion of phytol and fatty acids is converted into fatty acid phytyl esters and triacylglycerol during stress or senescence in chloroplasts. We isolated two genes (PHYTYL ESTER SYNTHASE1 [PES1] and PES2) of the esterase/lipase/thioesterase family of acyltransferases from Arabidopsis thaliana that are involved in fatty acid phytyl ester synthesis in chloroplasts. The two proteins are highly expressed during senescence and nitrogen deprivation. Heterologous expression in yeast revealed that PES1 and PES2 have phytyl ester synthesis and diacylglycerol acyltransferase activities. The enzymes show broad substrate specificities and can employ acyl-CoAs, acyl carrier proteins, and galactolipids as acyl donors. Double mutant plants (pes1 pes2) grow normally but show reduced phytyl ester and triacylglycerol accumulation. These results demonstrate that PES1 and PES2 are involved in the deposition of free phytol and free fatty acids in the form of phytyl esters in chloroplasts, a process involved in maintaining the integrity of the photosynthetic membrane during abiotic stress and senescence.

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

    Science.gov (United States)

    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.

  8. 21 CFR 172.852 - Glyceryl-lacto esters of fatty acids.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Glyceryl-lacto esters of fatty acids. 172.852... HUMAN CONSUMPTION Multipurpose Additives § 172.852 Glyceryl-lacto esters of fatty acids. Glyceryl-lacto esters of fatty acids (the lactic acid esters of mono- and diglycerides) may be safely used in food in...

  9. Extraction of Zinc and Manganese from Alkaline and Zinc-Carbon Spent Batteries by Citric-Sulphuric Acid Solution

    Directory of Open Access Journals (Sweden)

    Francesco Ferella

    2010-01-01

    Full Text Available The paper is focused on the recovery of zinc and manganese from alkaline and zinc-carbon spent batteries. Metals are extracted by sulphuric acid leaching in the presence of citric acid as reducing agent. Leaching tests are carried out according to a 24 full factorial design, and empirical equations for Mn and Zn extraction yields are determined from experimental data as a function of pulp density, sulphuric acid concentration, temperature, and citric acid concentration. The highest values experimentally observed for extraction yields were 97% of manganese and 100% of zinc, under the following operating conditions: temperature 40∘C, pulp density 20%, sulphuric acid concentration 1.8 M, and citric acid 40 g L-1. A second series of leaching tests is also performed to derive other empirical models to predict zinc and manganese extraction. Precipitation tests, aimed both at investigating precipitation of zinc during leaching and at evaluating recovery options of zinc and manganese, show that a quantitative precipitation of zinc can be reached but a coprecipitation of nearly 30% of manganese also takes place. The achieved results allow to propose a battery recycling process based on a countercurrent reducing leaching by citric acid in sulphuric solution.

  10. Quantification of uranyl in presence of citric acid; Cuantificacion de uranilo en presencia de acido citrico

    Energy Technology Data Exchange (ETDEWEB)

    Garcia G, N.; Barrera D, C.E. [UAEM, Facultad de Quimica, 50000 Toluca, Estado de Mexico (Mexico); Ordonez R, E. [ININ, 52750 La Marquesa, Estado de Mexico (Mexico)]. e-mail: nidgg@yahoo.com.mx

    2007-07-01

    To determine the influence that has the organic matter of the soil on the uranyl sorption on some solids is necessary to have a detection technique and quantification of uranyl that it is reliable and sufficiently quick in the obtaining of results. For that in this work, it intends to carry out the uranyl quantification in presence of citric acid modifying the Fluorescence induced by UV-Vis radiation technique. Since the uranyl ion is very sensitive to the medium that contains it, (speciation, pH, ionic forces, etc.) it was necessary to develop an analysis technique that stands out the fluorescence of uranyl ion avoiding the out one that produce the organic acids. (Author)

  11. Fabrication of a glucose biosensor based on citric acid assisted cobalt ferrite magnetic nanoparticles.

    Science.gov (United States)

    Krishna, Rahul; Titus, Elby; Chandra, Sudeshna; Bardhan, Neel Kanth; Krishna, Rohit; Bahadur, Dhirendra; Gracio, José

    2012-08-01

    A novel and practical glucose biosensor was fabricated with immobilization of Glucose oxidase (GOx) enzyme on the surface of citric acid (CA) assisted cobalt ferrite (CF) magnetic nanoparticles (MNPs). This innovative sensor was constructed with glassy carbon electrode which is represented as (GOx)/CA-CF/(GCE). An explicit high negative zeta potential value (-22.4 mV at pH 7.0) was observed on the surface of CA-CF MNPs. Our sensor works on the principle of detection of H2O2 which is produced by the enzymatic oxidation of glucose to gluconic acid. This sensor has tremendous potential for application in glucose biosensing due to the higher sensitivity 2.5 microA/cm2-mM and substantial increment of the anodic peak current from 0.2 microA to 10.5 microA.

  12. On a hypothetical generational relationship between HCN and constituents of the reductive citric acid cycle.

    Science.gov (United States)

    Eschenmoser, Albert

    2007-04-01

    Encouraged by observations made on the course of reactions the HCN-tetramer can undergo with acetaldehyde, I delineate a constitutional and potentially generational relationship between HCN and those constituents of the reductive citric acid cycle that are direct precursors of amino acids in contemporary metabolism. In this context, the robustness postulate of classical prebiotic chemistry is questioned, and, by an analysis of the (hypothetical) reaction-tree of a stepwise hydrolysis of the HCN-tetramer, it is shown how such a non-robust chemical reaction platform could harbor the potential for the emergence of autocatalytic cycles. It is concluded that the chemistry of HCN should be revisited by focussing on its non-robust parts in order to demonstrate its full potential as one of the possible roots of prebiotic self-organizing chemical processes.

  13. A Convenient Synthesis of Amino Acid Methyl Esters

    Directory of Open Access Journals (Sweden)

    Yaowu Sha

    2008-05-01

    Full Text Available A series of amino acid methyl ester hydrochlorides were prepared in good toexcellent yields by the room temperature reaction of amino acids with methanol in thepresence of trimethylchlorosilane. This method is not only compatible with natural aminoacids, but also with other aromatic and aliphatic amino acids.

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

    Science.gov (United States)

    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.

  15. Effect of citric acid and the hemihydrate amount on the properties of a calcium sulphoaluminate cement

    Directory of Open Access Journals (Sweden)

    Velazco, G.

    2014-12-01

    Full Text Available The influence of citric acid on the hydration and strength development of a calcium sulphoaluminate cement was investigated. Cement pastes were prepared by mixing calcium sulphoaluminate (C4A3Ŝ with 15, 20 and 25wt% of hemihydrate (CŜH0.5. Citric acid was added as a retarder at 0 and 0.5wt%. The samples were cured at 20 °C for periods of time from 1 to 28 days to evaluate their compressive strength and to characterize the hydration products by scanning electron microscopy and X-ray diffraction. Calorimetric curves showed that the retarding agent considerably decreases the heat release rate and the quantity of total heat released. The main product after the curing was ettringite (C6AŜ3H32. The morphology of this phase consisted of long and thin needles growing radially on the cement grains. Samples with 15wt% of hemihydrate and 0.5wt% of citric acid developed the highest compressive strength (70 MPa at 28 days of curing.Se investigó el efecto del ácido cítrico sobre la hidratación y propiedades mecánicas de un cemento de sulfoaluminato de calcio. El C4A3Ŝ se mezcló con 15, 20 y 25% e.p. de hemihidrato (CŜH0.5. Se agregó ácido cítrico como retardante en 0 y 0.5% e.p. Las muestras fueron curadas a 20 °C por periodos de 1 a 28 días para realizar mediciones de resistencia a la compresión y caracterizar los productos de hidratación mediante microscopía electrónica de barrido y difracción de rayos X. Las curvas de calorimetría mostraron ue el ácido cítrico disminuye la velocidad de liberación de calor y la cantidad de calor liberado durante la hidratación. La resistencia a la compresión alcanzó un máximo de 70 MPa en muestras con 15% e.p. de hemihidrato y 0,5% e.p de ácido cítrico. Los resultados muestran a la etringita (C6AŜ3H32 como principal producto de hidratación. Se observa a esta fase con morfología acicular creciendo sobre las partículas de cemento.

  16. Enhancing phosphate adsorption capacity of SDS-based magnetite by surface modification of citric acid

    Science.gov (United States)

    Yu, Zhigang; Zhang, Chang; Zheng, Zuhong; Hu, Liang; Li, Xuemei; Yang, Zhongzhu; Ma, Chi; Zeng, Guangming

    2017-05-01

    In this study, citric acid (CA) was employed as a low-molecule organic acid to influence the adsorption performance of phosphorus by as-obtained magnetite. The factors including initial phosphate concentrations, dosage of citric acid, pH value, ion strength, contact time and temperature were examined in detail. Results indicated that the dissolution of anion sodium dodecyl sulfate (SDS) covering on surface of magnetite, a slight decrease of Fe level and a superior structure of magnetite after CA modification occurred. The pH-dependence of phosphate adsorption was impeded and the surface potential of magnetite positively increased at pH > 5.0 when CA was added. Non-linear regression Langmuir-Freundlich model was fitted well in thermodynamics, and the opposite adsorption process as a function of temperatures with or without CA addition was due to the decrease of active energy and active mobility of phosphate ion. Finally, the declining adsorption efficiency with increasing cycles was observed while phosphate removal was approximately finished and had small change with 0.05 and 0.1 M of CA addition. Those improvements of removal efficiency of phosphorus by modified iron oxide were because of the removal of anionic SDS that increased the surface positive charge, and especially the dissolution of element Fe into solution to form precipitate with phosphorus ions. The enhanced stability of magnetite by CA also promoted the high removal efficiency of phosphorus. These implications of CA on phosphate removal can be extended to the field where phosphate pollution is notorious but urgent.

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

    Science.gov (United States)

    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.

  18. Microwave-assisted preparation of naphthenic acid esters

    Directory of Open Access Journals (Sweden)

    VERA CIRIN-NOVTA

    2006-12-01

    Full Text Available The synthesis of esters of natural petroleum acids of the naphthenic type assisted with microwave irradiation under the conditions of acid catalysis was carried out with various alcohols: methanol, ethanol, n-butanol and tert-butyl alcohol. Microwave dielectric heating of the reaction mixture in an unmodified microwave oven with activation of the naphthenic acids with sulfuric and p-toluenesulfonic acid afforded the esters of the naphthenic acids. Depending on the catalyst and the steric and nucleophilic properties of the alcohols, the yield of naphthenic esters ranged from 31.25 % to 88.90 %. As a consequence of microwave dielectric heating, the esterification time was reduced from 6–10 h to 5 min.

  19. Foliar sprays of citric acid and salicylic acid alter the pattern of root acquisition of some minerals in sweet basil (Ocimum basilicum L.

    Directory of Open Access Journals (Sweden)

    Noushin eGhazijahani

    2014-10-01

    Full Text Available The effect of foliar application of two levels of citric acid (0 and 7 mM and two levels of salicylic acid (0 and 1mM 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. Salicylic acid 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 citric acid and 1 mM of salicylic acid. Applying combination of citric acid and salicylic acid was more effective than using them individually that suggests an effective synergism between them.

  20. Effect of EDTA and citric acid on phytoremediation of Cr- B[a]P-co-contaminated soil.

    Science.gov (United States)

    Chigbo, Chibuike; Batty, Lesley

    2013-12-01

    Polycyclic aromatic hydrocarbons and heavy metals in the environment are a concern, and their removal to acceptable level is required. Phytoremediation, the use of plants to treat contaminated soils, could be an interesting alternative to conventional remediation processes. This work evaluates the role of single and combined applications of chelates to single or mixed Cr + benzo[a]pyrene (B[a]P)-contaminated soil. Medicago sativa was grown in contaminated soil and was amended with 0.3 g citric acid, 0.146 g ethylenediaminetetraacetic acid (EDTA), or their combination for 60 days. The result shows that in Cr-contaminated soil, the application of EDTA + citric acid significantly (pEDTA and EDTA + citric acid in co-contaminated soil increased the removal of Cr from the soil (34 and 54 %, respectively). The dissipation of B[a]P in single B[a]P-contaminated soil was effective even without planting and amendment with chelates, while in co-contaminated soil, it was related to the application of either EDTA or EDTA + citric acid. This suggests that M. sativa with the help of chelates in single or co-contaminated soil can be effective in phytoextraction of Cr and promoting the biodegradation of B[a]P.

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

    Science.gov (United States)

    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.

  2. Do mitochondria regulate cellular iron homeostasis through citric acid and haem production? Implications for cancer and other diseases.

    Science.gov (United States)

    Johnson, S

    2003-01-01

    Citric acid is produced industrially by depriving Aspergillus niger of iron. The lack of Fe deactivates mitochondrial aconitase and interrupts the krebs cycle, causing the mitochondria to release citric acid as a siderophore (an Fe getter). When the mitochondrion has plenty of Fe and the cell has enough ATP, aerobic phosphorylation stops and fatty acid or haem synthesis take place, when the cell has plenty of haem, haem synthesis stops. Since most of the Fe activity in the cell is related to the mitochondria, I hypothesise that in the animal cell when the mitochondria are low in Fe, citric acid acts as a signal that triggers the production of transferrin receptor messenger RNA (TrR mRNA) in the nucleus, which in the absence of Fe causes the expression of transferrin receptor. When the cell has plenty of Fe, cytosolic aconitase detaches itself from the transferrin receptor and ferritin mRNA stopping expression of the former and initiating expression of the latter. The detached cytosolic aconitase transforms the citric acid, blocking the production of the transferrin receptor mRNA.

  3. Impact of citric acid and calcium ions on acid solubilization of mechanically separated turkey meat: effect on lipid and pigment content.

    Science.gov (United States)

    Hrynets, Y; Omana, D A; Xu, Y; Betti, M

    2011-02-01

    Increased demand for poultry products has resulted in an increased availability of by-products, such as the neck, back, and frame, that can be processed into mechanically separated poultry meat. The major problems with mechanically separated poultry meat are its high lipid content, color instability, and high susceptibility to lipid oxidation. The present work was undertaken to determine the effect of different concentrations of citric acid and calcium ions on protein yield, color characteristics, and lipid removal from protein isolates prepared using an acid-aided extraction process. Six levels of citric acid (0, 2, 4, 6, 8, and 10 mmol/L) and 2 levels of calcium chloride (0 and 8 mmol/L) were examined. The entire experiment was replicated 3 times, resulting in 36 extractions (3 × 6 × 2). The highest (P citric acid. In general, all the combinations removed an average of 90.8% of the total lipids from mechanically separated turkey meat, ranging from 86.2 to 94.7%. The lowest amount (1.14%) of total lipids obtained was for samples treated with 4 mmol/L of citric acid. Maximum removal of neutral lipids (96.5%) and polar lipids (96.4%) was attained with the addition of 6 and 2 mmol/L of citric acid, respectively. Polar lipid content was found to be significantly (P = 0.0045) affected by the presence of calcium chloride. The isolated proteins were less (P citric acid. Addition of calcium chloride had a negative effect on total pigment content. The study revealed that acid extractions with the addition of citric acid resulted in substantial removal of lipids and pigments from mechanically separated turkey meat, improved stability of the recovered proteins against lipid oxidation, and appreciable protein recovery yields.

  4. [Metabolism of Yarrowia lipolytica grown on ethanol under conditions promoting the production of alpha-ketoglutaric and citric acids: a comparative study of the central metabolism enzymes].

    Science.gov (United States)

    Il'chenko, A P; Cherniavskaia, O G; Shishkanova, N V; Finogenova, T V

    2002-01-01

    A comparative study of the enzymes of the tricarboxylic acid (TCA) and glyoxylate cycles in the mutant Yarrowia lipolytica strain N1 capable of producing alpha-ketoglutaric acid (KGA) and citric acid showed that almost all enzymes of the TCA cycle are more active under conditions promoting the production of KGA. The only exception was citrate synthase, whose activity was higher in yeast cells producing citric acid. The production of both acids was accompanied by suppression of the glyoxylate cycle enzymes. The activities of malate dehydrogenase, aconitase, NADP-dependent isocitrate dehydrogenase, and fumarase were higher in cells producing KGA than in cells producing citric acid.

  5. 21 CFR 184.1101 - Diacetyl tartaric acid esters of mono- and diglycerides.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Diacetyl tartaric acid esters of mono- and... acid esters of mono- and diglycerides. (a) Diacetyl tartaric acid esters of mono- and diglycerides, also know as DATEM, are composed of mixed esters of glycerin in which one or more of the hydroxyl...

  6. Effects of uncoated and citric acid coated cerium oxide nanoparticles, bulk cerium oxide, cerium acetate, and citric acid on tomato plants

    Energy Technology Data Exchange (ETDEWEB)

    Barrios, Ana Cecilia [Department of Chemistry, The University of Texas at El Paso, 500 W. University Avenue, El Paso, TX 79968 (United States); Rico, Cyren M. [Department of Chemistry, The University of Texas at El Paso, 500 W. University Avenue, El Paso, TX 79968 (United States); University of California Center for Environmental Implications of Nanotechnology (UC CEIN), The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968 (United States); Trujillo-Reyes, Jesica [Department of Chemistry, The University of Texas at El Paso, 500 W. University Avenue, El Paso, TX 79968 (United States); Medina-Velo, Illya A. [Department of Chemistry, The University of Texas at El Paso, 500 W. University Avenue, El Paso, TX 79968 (United States); University of California Center for Environmental Implications of Nanotechnology (UC CEIN), The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968 (United States); Peralta-Videa, Jose R. [Department of Chemistry, The University of Texas at El Paso, 500 W. University Avenue, El Paso, TX 79968 (United States); Environmental Science and Engineering Ph.D. Program, The University of Texas at El Paso, 500 W. University Avenue, El Paso, TX 79968 (United States); University of California Center for Environmental Implications of Nanotechnology (UC CEIN), The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968 (United States); Gardea-Torresdey, Jorge L., E-mail: jgardea@utep.edu [Department of Chemistry, The University of Texas at El Paso, 500 W. University Avenue, El Paso, TX 79968 (United States); Environmental Science and Engineering Ph.D. Program, The University of Texas at El Paso, 500 W. University Avenue, El Paso, TX 79968 (United States); University of California Center for Environmental Implications of Nanotechnology (UC CEIN), The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968 (United States)

    2016-09-01

    Little is known about the physiological and biochemical responses of plants exposed to surface modified nanomaterials. In this study, tomato (Solanum lycopersicum L.) plants were cultivated for 210 days in potting soil amended with uncoated and citric acid coated cerium oxide nanoparticles (nCeO{sub 2}, CA + nCeO{sub 2}) bulk cerium oxide (bCeO{sub 2}), and cerium acetate (CeAc). Millipore water (MPW), and citric acid (CA) were used as controls. Physiological and biochemical parameters were measured. At 500 mg/kg, both the uncoated and CA + nCeO{sub 2} increased shoot length by ~ 9 and ~ 13%, respectively, while bCeO{sub 2} and CeAc decreased shoot length by ~ 48 and ~ 26%, respectively, compared with MPW (p ≤ 0.05). Total chlorophyll, chlo-a, and chlo-b were significantly increased by CA + nCeO{sub 2} at 250 mg/kg, but reduced by bCeO{sub 2} at 62.5 mg/kg, compared with MPW. At 250 and 500 mg/kg, nCeO{sub 2} increased Ce in roots by 10 and 7 times, compared to CA + nCeO{sub 2}, but none of the treatments affected the Ce concentration in above ground tissues. Neither nCeO{sub 2} nor CA + nCeO{sub 2} affected the homeostasis of nutrient elements in roots, stems, and leaves or catalase and ascorbate peroxidase in leaves. CeAc at 62.5 and 125 mg/kg increased B (81%) and Fe (174%) in roots, while at 250 and 500 mg/kg, increased Ca in stems (84% and 86%, respectively). On the other hand, bCeO{sub 2} at 62.5 increased Zn (152%) but reduced P (80%) in stems. Only nCeO{sub 2} at 62.5 mg/kg produced higher total number of tomatoes, compared with control and the rest of the treatments. The surface coating reduced Ce uptake by roots but did not affect its translocation to the aboveground organs. In addition, there was no clear effect of surface coating on fruit production. To our knowledge, this is the first study comparing the effects of coated and uncoated nCeO{sub 2} on tomato plants. - Highlights: • At 500 mg/kg, coated and bare NPs increased stem length by 13 and 9

  7. Citric Acid Capped Iron Oxide Nanoparticles as an Effective MALDI Matrix for Polymers

    Science.gov (United States)

    Liang, Qiaoli; Sherwood, Jennifer; Macher, Thomas; Wilson, Joseph M.; Bao, Yuping; Cassady, Carolyn J.

    2016-12-01

    A new matrix-assisted laser desorption ionization (MALDI) mass spectrometry matrix is proposed for molecular mass determination of polymers. This matrix contains an iron oxide nanoparticle (NP) core with citric acid (CA) molecules covalently bound to the surface. With the assistance of additives, the particulate nature of NPs allows the matrix to mix uniformly with polar or nonpolar polymer layers and promotes ionization, which may simplify matrix selection and sample preparation procedures. Several distinctively different polymer classes (polyethyleneglycol (PEG), polywax/polyethylene, perfluoropolyether, and polydimethylsiloxane) are effectively detected by the water or methanol dispersed NPCA matrix with NaCl, NaOH, LiOH, or AgNO3 as additives. Furtheremore, successful quantitative measurements of PEG1000 using polypropylene glycol 1000 as an internal standard are demonstrated.

  8. Electron Donor-Acceptor Interaction of 8-Hydroxyquinoline with Citric Acid in Different Solvents: Spectroscopic Studies

    Directory of Open Access Journals (Sweden)

    Demelash Jado

    2014-01-01

    Full Text Available Charge transfer complex formation between 8-hydroxyquinoline as the electron donor and citric acid as the electron acceptor has been studied spectrophotometrically in ethanol and methanol solvents at room temperature. Absorption band due to charge transfer complex formation was observed near 320 and 325 nm in ethanol and methanol, respectively. The stoichiometric ratio of the complex has been found 3 : 1 by using Job’s and conductometric titration methods. Benesi-Hildebrand equation has been applied to estimate the formation constant and molecular extinction coefficient. It was found that the value of formation constant was larger in ethanol than in methanol. The physical parameters, ionization potential, and standard free energy change of the formed complex were determined and evaluated in the ethanol and methanol solvents.

  9. Ultrasound assisted citric acid mediated pectin extraction from industrial waste of Musa balbisiana.

    Science.gov (United States)

    Maran, J Prakash; Priya, B; Al-Dhabi, Naif Abdullah; Ponmurugan, K; Moorthy, I Ganesh; Sivarajasekar, N

    2017-03-01

    The objectives of the present work are to extract pectin from industrial waste of Musa balbisiana by ultrasound assisted citric acid mediated extraction method and optimization was done through central composite statistical experimental design under response surface methodology. The outcomes of this study exhibited that, process variables (ultrasound power, pH and extraction time) had considerable influence on the pectin extraction. Second order mathematical equation was constructed to predict the data through regression analysis. The optimal extraction process condition was ultrasound power of 323w, pH of 3.2, extraction time of 27min and SL (solid-liquid) ratio of 1:15g/ml. The mean experimental yield of pectin (8.99±0.018%) was fine accord among predicted yield of pectin (9.02%). Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Fluorescence Properties of Eu3+/Gd3+/Citric Acid Mixed Complexes Doping in Silicon Rubber Matrix

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Series of doped rare earth complexes-EuxGd(1-x)(CA)3·nH2O (CA=citric acid) were synthesized. Some characterizations were taken for these complexes. The experimental results shows that the doped rare earth complexes have the best fluorescence property when the ratio of Eu and Gd is from 0.7 to 0.3. Silicon rubber-based composites were prepared by mechanical blending the EuxGd(1-x)(CA)3·nH2O and silicon rubber. Then, the fluorescent property of the composites was studied. It is found that the fluorescence intensity of the composites increase linearly with the contents of the rare earth complexes increasing.

  11. Effect of trace elements on citric acid fermentation by Aspergillus niger.

    Science.gov (United States)

    Sánchez-Marroquín, A; Carreño, R; Ledezma, M

    1970-12-01

    Citric acid yields of 98.7% (sugar consumption basis) were reached in shaker flasks with mutant UV-ET-71-15 of Aspergillus niger in a resin-treated sucrose medium of the following composition (g/100 ml): sucrose, 14.0; NH(4)NO(3), 0.20; KH(2)PO(4), 0.10; MgSO(4).7H(2)O, 0.025; and (mg/liter): FeSO(4), 0.15 to 0.75; ZnSO(4), 0.10; and CuSO(4), 0.01. Yields of 75% were obtained in medium with resin-treated clarified syrup and 68% with ferrocyanide-treated blackstrap molasses. Optimal conditions included selection of appropriate pellets as inoculum at 3%, pH of 4.5, temperature at 30 C, agitation at 250 rev/min, and fermentation time of 8 days. The mutant tolerated high concentrations of trace elements.

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

    Science.gov (United States)

    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.

  13. Properties of baked foams from citric acid modified cassava starch and native cassava starch blends.

    Science.gov (United States)

    Pornsuksomboon, Kanlaya; Holló, Berta Barta; Szécsényi, Katalin Mészáros; Kaewtatip, Kaewta

    2016-01-20

    Starch foams from native cassava starch (NS) and citric acid modified cassava starch (CNS) were prepared using baking processes with blend ratios of 80/20, 60/40, 50/50, 40/60 and 20/80. The density, thickness, morphology, thermal stability and water absorption of the NS, CNS and blended starch foams were determined. The ratio of the two starch components had a significant influence on the density and thickness of the blended starch foams. All blended starch foams showed good water resistance. Moreover, the morphology of the blended starch foam with the NS/CNS ratio of 50/50 showed a more ordered distribution of cell sizes with thicker cell walls than for the NS and CNS foams. The thermal stability of the blended starch foams was somewhat lower than the stability of the NS foam but not to the extent that it affected any potential practical applications.

  14. Equilibrium concentrations for pyruvate dehydrogenase and the citric acid cycle at specified concentrations of certain coenzymes.

    Science.gov (United States)

    Alberty, Robert A

    2004-04-01

    It is of interest to calculate equilibrium compositions of systems of biochemical reactions at specified concentrations of coenzymes because these reactants tend to be in steady states. Thermodynamic calculations under these conditions require the definition of a further transformed Gibbs energy G" by use of a Legendre transform. These calculations are applied to the pyruvate dehydrogenase reaction plus the citric acid cycle, but steady-state concentrations of CoA, acetyl-CoA and succinyl-CoA cannot be specified because they are involved in the conservation of carbon atoms. These calculations require the use of linear algebra to obtain further transformed Gibbs energies of formation of reactants and computer programs to calculate equilibrium compositions. At specified temperature, pH, ionic strength and specified concentrations of several coenzymes, the equilibrium composition depends on the specified concentrations of the coenzymes and the initial amounts of reactants.

  15. Citric acid cycle in the hyperthermophilic archaeon Pyrobaculum islandicum grown autotrophically, heterotrophically, and mixotrophically with acetate.

    Science.gov (United States)

    Hu, Yajing; Holden, James F

    2006-06-01

    The hyperthermophilic archaeon Pyrobaculum islandicum uses the citric acid cycle in the oxidative and reductive directions for heterotrophic and autotrophic growth, respectively, but the control of carbon flow is poorly understood. P. islandicum was grown at 95 degrees C autotrophically, heterotrophically, and mixotrophically with acetate, H2, and small amounts of yeast extract and with thiosulfate as the terminal electron acceptor. The autotrophic growth rates and maximum concentrations of cells were significantly lower than those in other media. The growth rates on H2 and 0.001% yeast extract with and without 0.05% acetate were the same, but the maximum concentration of cells was fourfold higher with acetate. There was no growth with acetate if 0.001% yeast extract was not present, and addition of H2 to acetate-containing medium greatly increased the growth rates and maximum concentrations of cells. P. islandicum cultures assimilated 14C-labeled acetate in the presence of H2 and yeast extract with an efficiency of 55%. The activities of 11 of 19 enzymes involved in the central metabolism of P. islandicum were regulated under the three different growth conditions. Pyruvate synthase and acetate:coenzyme A (CoA) ligase (ADP-forming) activities were detected only in heterotrophically grown cultures. Citrate synthase activity decreased in autotrophic and acetate-containing cultures compared to the activity in heterotrophic cultures. Acetylated citrate lyase, acetate:CoA ligase (AMP forming), and phosphoenolpyruvate carboxylase activities increased in autotrophic and acetate-containing cultures. Citrate lyase activity was higher than ATP citrate synthase activity in autotrophic cultures. These data suggest that citrate lyase and AMP-forming acetate:CoA ligase, but not ATP citrate synthase, work opposite citrate synthase to control the direction of carbon flow in the citric acid cycle.

  16. Functional citric acid cycle in an arcA mutant of Escherichia coli during growth with nitrate under anoxic conditions.

    Science.gov (United States)

    Prohl, C; Wackwitz, B; Vlad, D; Unden, G

    1998-07-01

    The operation of the citric acid cycle of Escherichia coli during nitrate respiration (anoxic conditions) was studied by measuring end products and enzyme activities. Excretion of products other than CO2, such as acetate or ethanol, was taken as an indication for a non-functional cycle. From glycerol, approximately 0.3 mol acetate was produced; the residual portion was completely oxidized, indicating the presence of a partially active citric acid cycle. In an arcA mutant devoid of the transcriptional regulator ArcA, glycerol was completely oxidized with nitrate as an electron acceptor, demonstrating derepression and function of the complete pathway. Glucose, on the other hand, was excreted mostly as acetate by the wild-type and by the arcA mutant. During growth on glucose, but not on glycerol, activities of succinate dehydrogenase and of 2-oxoglutarate dehydrogenase were missing nearly completely. Thus, the previously described strong repression of the citric acid cycle during nitrate respiration occurs only during growth on glucose and is the effect of anaerobic and, more important, of glucose repression. In Pseudomonas fluorescens (but not Pseudomonas stutzeri), a similar decrease of citric acid cycle function during anaerobic growth with nitrate was found, indicating a broad distribution of this regulatory principle.

  17. CITRIC-ACID COUGH THRESHOLD AND AIRWAY RESPONSIVENESS IN ASTHMATIC-PATIENTS AND SMOKERS WITH CHRONIC AIR-FLOW OBSTRUCTION

    NARCIS (Netherlands)

    AUFFARTH, B; DEMONCHY, JGR; VANDERMARK, TW; POSTMA, DS; KOETER, GH

    1991-01-01

    The relation between citric acid cough threshold and airway hyperresponsiveness was investigated in 11 non-smoking patients with allergic asthma (mean FEV1 94% predicted) and 25 non-atopic smokers with chronic airflow obstruction (mean FEV1 65% predicted). Cough threshold was determined on two occas

  18. Dimethylurea/citric acid as a highly efficient deep eutectic solvent for the multi-component reactions

    Indian Academy of Sciences (India)

    Behnaz Bafti; Hojatollah Khabazzadeh

    2014-05-01

    Dimethylurea/citric acid deep eutectic solvent was used as a dual catalyst and a green reaction medium for the efficient synthesis of bis(indolyl)methanes, quinolines and aryl-4, 5-diphenyl-1H-imidazoles. Ease of recovery and reusability of DES with high activity makes this method efficient and eco-friendly.

  19. An increase in the threshold of citric acid-induced cough during chest wall vibration in healthy humans.

    Science.gov (United States)

    Kondo, T; Kobayashi, I; Hayama, N; Ohta, Y

    1998-10-01

    This study tested the hypothesis that the afferent input from the respiratory muscles may be involved in the neural mechanisms inducing cough responses. Coughing was evoked in conscious healthy humans by the inhalation of citric acid aerosol of several concentrations either during or not during chest wall vibration (100 Hz) at the right second intercostal space or during vibration of the right thigh. The mean threshold citric acid concentration to induce coughing was significantly higher during chest wall vibration (geometric mean, 131.8 mg/ml) than without vibration (75.9 mg/ml). Vibration after topical anesthesia of the chest wall skin did not significantly change the threshold concentration of citric acid. The threshold citric acid concentration during vibration of the right thigh did not significantly differ from that without vibration. We concluded that inputs from the chest wall afferent, presumably from the intercostal muscle or costovertebral joint, may have an inhibitory effect on the initiation of coughing at the higher neural structure in conscious humans.

  20. CITRIC-ACID COUGH THRESHOLD AND AIRWAY RESPONSIVENESS IN ASTHMATIC-PATIENTS AND SMOKERS WITH CHRONIC AIR-FLOW OBSTRUCTION

    NARCIS (Netherlands)

    AUFFARTH, B; DEMONCHY, JGR; VANDERMARK, TW; POSTMA, DS; KOETER, GH

    The relation between citric acid cough threshold and airway hyperresponsiveness was investigated in 11 non-smoking patients with allergic asthma (mean FEV1 94% predicted) and 25 non-atopic smokers with chronic airflow obstruction (mean FEV1 65% predicted). Cough threshold was determined on two

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

    Science.gov (United States)

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

    2013-11-01

    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.

  2. Citric acid: An efficient and green catalyst for rapid one pot synthesis of quinoxaline derivatives at room temperature

    Institute of Scientific and Technical Information of China (English)

    Radhakrishnan Mahesh; Arghya Kusum Dhar; Tara Sasank T.V.N.V.; Sappanimuthu Thirunavukkarasu; Thangaraj Devadoss

    2011-01-01

    The condensation of o-phenylenediamines with 1,2-dicarbonyl compounds in the presence of citric acid afforded the corresponding quinoxaline derivatives in higher yields at room temperature in ethanol, and most of the reactions were completed in less than 1 min.

  3. Sodium borohydride reduction of aromatic carboxylic acids via methyl esters

    Indian Academy of Sciences (India)

    Aamer Saeed; Zaman Ashraf

    2006-09-01

    A number of important aromatic carboxylic acids precursors, or intermediates in the syntheses of natural products, are converted into methyl esters and reduced to the corresponding primary alcohols using a sodium borohydride-THF-methanol system. The alcohols are obtained in 70-92% yields in 2-5 hours, in a pure state. This two-step procedure not only provides a better alternative to aluminum hydride reduction of acids but also allows the selective reduction of esters in presence of acids, amides, nitriles or nitro functions which are not affected under these conditions.

  4. Fragrance material review on carbonic acid, methyl phenylmethyl ester.

    Science.gov (United States)

    McGinty, D; Letizia, C S; Api, A M

    2012-09-01

    A toxicologic and dermatologic review of carbonic acid, methyl phenylmethyl ester when used as a fragrance ingredient is presented. Carbonic acid, methyl phenylmethyl ester is a member of the fragrance structural group Aryl Alkyl Alcohol Simple Acid Esters (AAASAE). The AAASAE fragrance ingredients are prepared by reacting an aryl alkyl alcohol with a simple carboxylic acid (a chain of 1-4 carbons) to generate formate, acetate, propionate, butyrate, isobutyrate and carbonate esters. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for carbonic acid, methyl phenylmethyl ester were evaluated, then summarized, and includes: physical properties, acute toxicity, skin irritation, and skin sensitization data. A safety assessment of the entire AAASAE will be published simultaneously with this document. Please refer to Belsito et al. (2012) for an overall assessment of the safe use of this material and all AAASAE in fragrances. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. Effects of high-melting methyl esters on crystallization properties of fatty acid methyl ester mixtures

    Science.gov (United States)

    Biodiesel is a renewable alternative diesel fuel made from vegetable oils and animal fats. The most common form of biodiesel in the United States are fatty acid methyl esters (FAME) from soybean, canola, and used cooking oils, waste greases, and tallow. Cold flow properties of biodiesel depend on th...

  6. Synthesis of fatty acid starch esters in supercritical carbon dioxide

    NARCIS (Netherlands)

    Muljana, Henky; van der Knoop, Sjoerd; Keijzer, Danielle; Picchioni, Francesco; Janssen, Leon P. B. M.; Heeres, Hero J.

    2010-01-01

    This manuscript describes an exploratory study on the synthesis of fatty acid/potato starch esters using supercritical carbon dioxide (scCO(2)) as the solvent. The effects of process variables such as pressure (6-25 MPa), temperature (120-150 degrees C) and various basic catalysts and fatty acid der

  7. The expanded Hansen approach to solubility parameters. Paracetamol and citric acid in individual solvents.

    Science.gov (United States)

    Barra, J; Lescure, F; Doelker, E; Bustamante, P

    1997-07-01

    In this study two solubility-parameter models have been compared using as dependent variables the logarithm of the mole fraction solubility, lnX2e, and ln(alpha)/U (originally used in the extended Hansen method), where alpha is the activity coefficient and U is a function of the molar volume of the solute and the volume fraction of the solvent. The results show for the first time the proton-donor and -acceptor hydrogen-bonding capacities of paracetamol, as measured by the acidic and basic partial-solubility parameters. The influence of solvents on the differential scanning calorimetry (DSC) pattern of the solid phases was also studied in relation to the solubility models tested. Citric acid was chosen as a test substance because of its high acidity and its proton donor capacity to form hydrogen bonds with basic solvents. The partial acidic and basic solubility parameters obtained from multiple regression were consistent with this property, validating the model chosen. The results show that the more direct lnX2e variable was more suitable for fitting both models, and the four-parameter model seemed better for describing the interactions between solvent and solute.

  8. 76 FR 41135 - 2-Propenoic acid, 2-methyl-, phenylmethyl ester, polymer with 2-propenoic acid and sodium 2...

    Science.gov (United States)

    2011-07-13

    ... AGENCY 40 CFR Part 180 2-Propenoic acid, 2-methyl-, phenylmethyl ester, polymer with 2- propenoic acid...-Propenoic acid, 2-methyl-, phenylmethyl ester, polymer with 2-propenoic acid and sodium 2-methyl- 2- -1... for residues of 2-Propenoic acid, 2-methyl-,phenylmethyl ester, polymer with 2-propenoic acid...

  9. 40 CFR 417.140 - Applicability; description of the neutralization of sulfuric acid esters and sulfonic acids...

    Science.gov (United States)

    2010-07-01

    ... neutralization of sulfuric acid esters and sulfonic acids subcategory. 417.140 Section 417.140 Protection of... MANUFACTURING POINT SOURCE CATEGORY Neutralization of Sulfuric Acid Esters and Sulfonic Acids Subcategory § 417.140 Applicability; description of the neutralization of sulfuric acid esters and sulfonic acids...

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

    Science.gov (United States)

    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.

  11. 柠檬酸改性糠醛渣的制备%Preparation of Modified Furfural Residue With Citric Acid

    Institute of Scientific and Technical Information of China (English)

    王昕; 邢琦; 任广军

    2014-01-01

    The preparation process of modified furfural residue with citric acid was studied as well as the optimum conditions for modification. The furfural residue was first pretreated, then it was treated by 20%isopropanol and 20%sodium hydroxide solution, at last the furfural residue was modified by citric acid to obtain the citric acid modified furfural residue. Effects of reaction time, reaction temperature, citric acid solution concentration, ratio of solid to liquid on the modification were investigated. The results show that,the best modification conditions are as follows:reaction time 60 min, reaction temperature 80 ℃, citric acid concentration 100 g/L, ratio of solid to liquid 1︰4. The modified furfural residue has good adsorption for methylene blue solution, removal rate can reach to 98.2%.%研究了柠檬酸改性糠醛渣的制备过程和条件。首先对糠醛渣进行预处理,然后分别用20%的异丙醇和20%的氢氧化钠溶液处理,最后用柠檬酸对其进行改性,得到柠檬酸改性糠醛渣。讨论了反应时间,反应温度,柠檬酸溶液浓度,固液比等因素对改性的影响。结果表明:当反应时间60 min,反应温度80℃,柠檬酸质量浓度100 g/L,固液比1︰3时获得的改性糠醛渣吸附亚甲基蓝效果最好,去除率可达到98.2%。

  12. C-Myc induced compensated cardiac hypertrophy increases free fatty acid utilization for the citric acid cycle.

    Science.gov (United States)

    Olson, Aaron K; Ledee, Dolena; Iwamoto, Kate; Kajimoto, Masaki; O'Kelly Priddy, Colleen; Isern, Nancy; Portman, Michael A

    2013-02-01

    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) injections. Isolated working hearts and (13)Carbon ((13)C)-NMR were used to measure function and fractional contributions (Fc) to the citric acid cycle by using perfusate containing (13)C-labeled free fatty acids, 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 assessed 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 contributions in NTG. Substrate utilization was not significantly altered in 3dMyc versus Cont. The free fatty acid FC was significantly greater in 7dMyc versus 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 for the citric acid cycle 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

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

    Directory of Open Access Journals (Sweden)

    Dappili SwamiRanga Reddy

    2014-01-01

    Full Text Available 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, ΅m 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

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  16. The citric acid production from raw glycerol by Yarrowia lipolytica yeast and its regulation.

    Science.gov (United States)

    Morgunov, Igor G; Kamzolova, Svetlana V; Lunina, Julia N

    2013-08-01

    The optimal cultivation conditions ensuring the maximal rate of citric acid (CA) biosynthesis by glycerol-grown mutant Yarrowia lipolytica NG40/UV7 were found to be as follows: growth limitation by inorganic nutrients (nitrogen, phosphorus, or sulfur), 28 °C, pH 5.0, dissolved oxygen concentration (pO₂) of 50 % (of air saturation), and pulsed addition of glycerol from 20 to 80 g L⁻¹ depending on the rate of medium titration. Under optimal conditions of fed-batch cultivation, in the medium with pure glycerol, strain Y. lipolytica NG40/UV7 produced 115 g L⁻¹ of CA with the mass yield coefficient of 0.64 g g⁻¹ and isocitric acid (ICA) amounted to 4.6 g L⁻¹; in the medium with raw glycerol, CA production was 112 g L⁻¹ with the mass yield coefficient of 0.90 g g⁻¹ and ICA amounted to 5.3 g L⁻¹. Based on the activities of enzymes involved in the initial stages of raw glycerol assimilation, the tricarboxylic acid cycle and the glyoxylate cycle, the mechanism of increased CA yield from glycerol-containing substrates in Y. lipolytica yeast was explained.

  17. 21 CFR 172.850 - Lactylated fatty acid esters of glycerol and propylene glycol.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Lactylated fatty acid esters of glycerol and... esters of glycerol and propylene glycol. The food additive lactylated fatty acid esters of glycerol and... additive is a mixture of esters produced by the lactylation of a product obtained by reacting edible fats...

  18. Methods of refining and producing dibasic esters and acids from natural oil feedstocks

    Energy Technology Data Exchange (ETDEWEB)

    Snead, Thomas E.; Cohen, Steven A.; Gildon, Demond L.

    2016-06-14

    Methods and systems for making dibasic esters and/or dibasic acids using metathesis are generally disclosed. In some embodiments, the methods comprise reacting a terminal olefin ester with an internal olefin ester in the presence of a metathesis catalyst to form a dibasic ester and/or dibasic acid. In some embodiments, the terminal olefin ester or the internal olefin ester are derived from a renewable feedstock, such as a natural oil feedstock. In some such embodiments, the natural oil feedstock, or a transesterified derivative thereof, is metathesized to make the terminal olefin ester or the internal olefin ester.

  19. Stereoselective Formation of Trisubstituted Vinyl Boronate Esters by the Acid-Mediated Elimination of α-Hydroxyboronate Esters

    OpenAIRE

    Guan, Weiye; Michael, Alicia K.; McIntosh, Melissa L.; Koren-Selfridge, Liza; Scott, John P.; Clark, Timothy B.

    2014-01-01

    The copper-catalyzed diboration of ketones followed by an acid-catalyzed elimination leads to the formation of 1,1-disubstituted and trisubstituted vinyl boronate esters with moderate to good yields and selectivity. Addition of tosic acid to the crude diboration products provides the corresponding vinyl boronate esters upon elimination. The trisubstituted vinyl boronate esters are formed as the (Z)-olefin isomer, which was established by subjecting the products to a Suzuki–Miyaura coupling re...

  20. Insights into cadmium induced physiological and ultra-structural disorders in Juncus effusus L. and its remediation through exogenous citric acid

    Energy Technology Data Exchange (ETDEWEB)

    Najeeb, Ullah [Institute of Crop Science, Zhejiang University, Hangzhou 310029 (China); Crop Sciences Institute, National Agriculture Research Centre, Islamabad 45500 (Pakistan); Jilani, Ghulam, E-mail: jilani@uaar.edu.pk [Department of Soil Science, PMAS Arid Agriculture University, Rawalpindi, Punjab 46300 (Pakistan); Ali, Shafaqat [Institute of Crop Science, Zhejiang University, Hangzhou 310029 (China); Sarwar, Muhammad [Land Resources Research Institute, National Agriculture Research Centre, Islamabad 45500 (Pakistan); Xu Ling [Institute of Crop Science, Zhejiang University, Hangzhou 310029 (China); Zhou, Weijun, E-mail: wjzhou@zju.edu.cn [Institute of Crop Science, Zhejiang University, Hangzhou 310029 (China)

    2011-02-15

    This study appraised cadmium (Cd) toxicity stress in wetland plant Juncus effusus, and explored its potential for Cd phytoextraction through chelators (citric acid and EDTA). Cadmium altered morphological and physiological attributes of J. effusus as reflected by growth retardation. Citric acid in the presence of 100 {mu}M Cd significantly countered Cd toxicity by improving plant growth. Elevated Cd concentrations reduced translocation factor that was increased under application of both chelators. Citric acid enhanced Cd accumulation, while EDTA reduced its uptake. Cadmium induced oxidative stress modified the antioxidative enzyme activity. Both levels of citric acid (2.5 and 5.0 mM) and lower EDTA concentration (2.5 mM) helped plants to overcome oxidative stress by enhancing their antioxidative enzyme activities. Cadmium damaged the root cells through cytoplasmic shrinkage and metal deposition. Citric acid restored structure and shape of root cells and eliminated plasmolysis; whereas, EDTA exhibited no positive effect on it. Shoot cells remained unaffected under Cd treatment alone or with citric acid except for chloroplast swelling. Only EDTA promoted starch accumulation in chloroplast reflecting its negative impact on cellular structure. It concludes that Cd and EDTA induce structural and morphological damage in J. effusus; while, citric acid ameliorates Cd toxicity stress.

  1. 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.

    Science.gov (United States)

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

    2017-02-03

    Effects of citric acid and desferrioxamine B (DFO-B) on the availability of Ge and selected REEs (La, Nd, Gd, Er) to P. 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, 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.

  2. Vinylic polymerization of Norbornenecarboxylic Acid Esters by Palladium Complexes

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    New thermoplastic norbornene polymers containing ester groups were prepared byvinylic polymerization of norbornene-carboxylic acid esters by Pd(Ⅱ)-based catalysts. Themonomers were obtained by Diels-Alder reaction of cyclopentadiene with acrylic acid esters(methyl and butyl) as mixtures of endo/exo (ratio 40/60)-isomers and were converted topolymers in 60%~70% conversion. The endo-isomer was less reactive than the exo-isomer.To obtain higher molecular weight the more reactive pure exo-isomer was prepared andpolymerized with the Pd (Ⅱ)-catalysts, tetrakis (acetonitrile) Pd (Ⅱ) bis (tetrafluoroborate)and (η3-allyl)Pd(Ⅱ)SbF6, in high conversion. These polymers showed high glass transitiontemperatures, high transparency and good solubility in common solvents.

  3. Electron driven processes in chlorodifluoroacetic acid methyl ester

    Science.gov (United States)

    Kopyra, Janina

    2014-07-01

    Dissociative electron attachment to gas phase 2-chloro-2,2-difluoroacetic acid methyl ester (CClF2COOCH3) is studied by means of a crossed beams apparatus. Effective cleavage of the C-Cl bond is observed within a broad resonance in the energy range 0-1 eV and visible via the appearance of the light fragment Cl-. In chlorodifluoroacetic acid cleavage of the C-Cl bond was observed not only via the Cl- anion formation but predominantly via expulsion of the neutral chlorine atom leading to the formation of the (M-Cl)- anion. Similar to the previously studied esters CF3COOCH3 and CF3COOC2H5[I. Martin, J. Langer, E. Illenberger, Z. Phys. Chem. 222, 1185 (2008)], we observe reaction due to the cleavage of the ester bond resulting in the formation of the closed shell (M-CH3)- anion.

  4. Regulation of pyruvate dehydrogenase activity and citric acid cycle intermediates during high cardiac power generation.

    Science.gov (United States)

    Sharma, Naveen; Okere, Isidore C; Brunengraber, Daniel Z; McElfresh, Tracy A; King, Kristen L; Sterk, Joseph P; Huang, Hazel; Chandler, Margaret P; Stanley, William C

    2005-01-15

    A high rate of cardiac work increases citric acid cycle (CAC) turnover and flux through pyruvate dehydrogenase (PDH); however, the mechanisms for these effects are poorly understood. We tested the hypotheses that an increase in cardiac energy expenditure: (1) activates PDH and reduces the product/substrate ratios ([NADH]/[NAD(+)] and [acetyl-CoA]/[CoA-SH]); and (2) increases the content of CAC intermediates. Measurements were made in anaesthetized pigs under control conditions and during 15 min of a high cardiac workload induced by dobutamine (Dob). A third group was made hyperglycaemic (14 mm) to stimulate flux through PDH during the high work state (Dob + Glu). Glucose and fatty acid oxidation were measured with (14)C-glucose and (3)H-oleate. Compared with control, the high workload groups had a similar increase in myocardial oxygen consumption ( and cardiac power. Dob increased PDH activity and glucose oxidation above control, but did not reduce the [NADH]/[NAD(+)] and [acetyl-CoA]/[CoA-SH] ratios, and there were no differences between the Dob and Dob + Glu groups. An additional group was treated with Dob + Glu and oxfenicine (Oxf) to inhibit fatty acid oxidation: this increased [CoA-SH] and glucose oxidation compared with Dob; however, there was no further activation of PDH or decrease in the [NADH]/[NAD(+)] ratio. Content of the 4-carbon CAC intermediates succinate, fumarate and malate increased 3-fold with Dob, but there was no change in citrate content, and the Dob + Glu and Dob + Glu + Oxf groups were not different from Dob. In conclusion, compared with normal conditions, at high myocardial energy expenditure (1) the increase in flux through PDH is regulated by activation of the enzyme complex and continues to be partially controlled through inhibition by fatty acid oxidation, and (2) there is expansion of the CAC pool size at the level of 4-carbon intermediates that is largely independent of myocardial fatty acid oxidation.

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

    Science.gov (United States)

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

    2015-05-01

    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.

  6. Iron Absorption from Two Milk Formulas Fortified with Iron Sulfate Stabilized with Maltodextrin and Citric Acid

    Science.gov (United States)

    Pizarro, Fernando; Olivares, Manuel; Maciero, Eugenia; Krasnoff, Gustavo; Cócaro, Nicolas; Gaitan, Diego

    2015-01-01

    Background: Fortification of milk formulas with iron is a strategy widely used, but the absorption of non-heme iron is low. The purpose of this study was to measure the bioavailability of two iron fortified milk formulas designed to cover toddlers’ nutritional needs. These milks were fortified with iron sulfate stabilized with maltodextrin and citric acid. Methods: 15 women (33–47 years old) participated in study. They received on different days, after an overnight fast, 200 mL of Formula A; 200 mL of Formula B; 30 mL of a solution of iron and ascorbic acid as reference dose and 200 mL of full fat cow’s milk fortified with iron as ferrous sulfate. Milk formulas and reference dose were labeled with radioisotopes 59Fe or 55Fe, and the absorption of iron measured by erythrocyte incorporation of radioactive Fe. Results: The geometric mean iron absorption corrected to 40% of the reference dose was 20.6% for Formula A and 20.7% for Formula B, versus 7.5% of iron fortified cow’s milk (p < 0.001). The post hoc Sheffé indeed differences between the milk formulas and the cow’s milk (p < 0.001). Conclusion: Formulas A and B contain highly bioavailable iron, which contributes to covering toddlers’ requirements of this micronutrient. PMID:26529007

  7. Effect of Plant Oils upon Lipase and Citric Acid Production in Yarrowia lipolytica Yeast

    Directory of Open Access Journals (Sweden)

    Farshad Darvishi

    2009-01-01

    Full Text Available The nonconventional yeast Yarrowia lipolytica degrades very efficiently hydrophobic substrates to produce organic acids, single-cell oil, lipases, and so forth. The aim of this study was to investigate the biochemical behavior and simultaneous production of valuable metabolites such as lipase, citric acid (CA, and single-cell protein (SCP by Yarrowia lipolytica DSM 3286 grown on various plant oils as sole carbon source. Among tested plant oils, olive oil proved to be the best medium for lipase and CA production. The Y. lipolytica DSM 3286 produced 34.6 ± 0.1 U/mL of lipase and also CA and SCP as by-product on olive oil medium supplemented with yeast extract. Urea, as organic nitrogen, was the best nitrogen source for CA production. The results of this study suggest that the two biotechnologically valuable products, lipase and CA, could be produced simultaneously by this strain using renewable low-cost substrates such as plant oils in one procedure.

  8. Citric acid production from Aspergillus niger MT-4 using hydrolysate extract of the insect Locusta migratoria.

    Science.gov (United States)

    Taskin, Mesut; Tasar, Gani Erhan; Incekara, Umit

    2013-06-01

    Citric acid (CA) is the most important organic acid used in the food and other industries. Locusta migratoria is an insect species, which has rich nutritional composition (especially protein) and cultivated in some countries. Therefore, the present study investigated the usability of hydrolysate extract of L. migratoria biomass as substrate for the production of CA from Aspergillus niger MT-4. The insect extract (IE) was found to be rich in ash (34.9 g/100 g), protein (35.6 g/100 g) and mineral contents. Yeast extract was found to be the most favorable substrate for biomass production, whereas the maximum production of CA (41.8 g/L) was achieved in the medium containing IE. Besides, uniform pellets with the smallest size (4 mm) were observed in IE medium. It was thought that rich magnesium (6.78 g/100 g) and manganese (1.14 g/100 g) contents of IE increased the production of CA, resulting in the formation of small uniform pellets. This is the first report on the effect of protein-rich insect biomasses on the production of CA. In this regard, L. migratoria biomass was tested for the first time as a CA-production substrate.

  9. Efficacy of different final irrigant activation protocols on smear layer removal by EDTA and citric acid.

    Science.gov (United States)

    Herrera, Daniel R; Santos, Zarina T; Tay, Lidia Y; Silva, Emmanuel J; Loguercio, Alessandro D; Gomes, Brenda P F A

    2013-04-01

    The aim of this study was to evaluate the influence of different activation protocols for chelating agents used after chemo-mechanical preparation (CMP), for smear layer (SL) removal. Forty-five single-rooted human premolars with straight canals and fully formed apex were selected. The specimens were randomly divided into three groups depending on the chelating agent used for smear layer removal: distilled water (DW, control group); 17% ethylenediaminetetraacetic acid (EDTA); and 10% citric acid (CA). Each group was further divided into three subgroups according to the activation protocol used: no-activation (NA), manual dynamic activation (MDA), or sonic activation (SA). After CMP, all specimens were sectioned and processed for observation of the apical thirds by using scanning electron microscopy (SEM). Two calibrated evaluators attributed scores to each specimen. The differences between activation protocols were analyzed with Kruskal-Wallis and Mann-Whitney U tests. Friedman and Wilcoxon signed rank tests were used for comparison between each root canal third. When chelating agents were activated, either by MDA or SA, it was obtained the best cleaning results with no significant difference between EDTA and CA (P > 0.05). Sonic activation showed the best results when root canal thirds were analyzed, in comparison to MDA and NA groups (P benefits smear layer removal from root canals.

  10. Effects of Citric and Lactic Acid on the Reduction of Deoxynivalenol and Its Derivatives in Feeds

    Science.gov (United States)

    Humer, Elke; Lucke, Annegret; Harder, Hauke; Metzler-Zebeli, Barbara U.; Böhm, Josef; Zebeli, Qendrim

    2016-01-01

    Exposure to mycotoxin-contaminated feeds represents a serious health risk. This has necessitated the need for the establishment of practical methods for mycotoxin decontamination. This study investigated the effects of citric acid (CA) and lactic acid (LA) on common trichothecene mycotoxins in feeds contaminated with Fusarium mycotoxins. Contaminated feed samples were processed either with 5% CA or 5% LA solutions in a ratio of 1:1.2 (w/v) for 5, 24, or 48 h, and analyzed for multiple mycotoxin metabolites using a liquid chromatography–tandem mass spectrometric method. The analyses showed that treating the feed with CA and LA lowered the concentration of deoxynivalenol (DON), whereby 5% LA lowered the original DON concentration in the contaminated feed samples by half, irrespective of the processing time. Similar lowering effects were observed for the concentrations of 15Ac-DON, 5-hydroxyculmorin, and sambucinol. The concentration of nivalenol was only lowered by the LA treatment. In contrast, CA and LA treatments showed no or only small effects on the concentration of several mycotoxins and their derivatives, including zearalenone, fumonisins, and culmorin. In conclusion, the present results indicate that the use of 5% solutions of LA and CA might reduce the concentration of common trichothecene mycotoxins, especially DON and its derivate 15Ac-DON. However, further research is required to determine the effect on overall toxicity and to identify the underlying mechanisms. PMID:27690101

  11. Iron Absorption from Two Milk Formulas Fortified with Iron Sulfate Stabilized with Maltodextrin and Citric Acid

    Directory of Open Access Journals (Sweden)

    Fernando Pizarro

    2015-10-01

    Full Text Available Background: Fortification of milk formulas with iron is a strategy widely used, but the absorption of non-heme iron is low. The purpose of this study was to measure the bioavailability of two iron fortified milk formulas designed to cover toddlers´ nutritional needs. These milks were fortified with iron sulfate stabilized with maltodextrin and citric acid. Methods: 15 women (33–47 years old participated in study. They received on different days, after an overnight fast, 200 mL of Formula A; 200 mL of Formula B; 30 mL of a solution of iron and ascorbic acid as reference dose and 200 mL of full fat cow’s milk fortified with iron as ferrous sulfate. Milk formulas and reference dose were labeled with radioisotopes 59Fe or 55Fe, and the absorption of iron measured by erythrocyte incorporation of radioactive Fe. Results: The geometric mean iron absorption corrected to 40% of the reference dose was 20.6% for Formula A and 20.7% for Formula B, versus 7.5% of iron fortified cow’s milk (p < 0.001. The post hoc Sheffé indeed differences between the milk formulas and the cow’s milk (p < 0.001. Conclusion: Formulas A and B contain highly bioavailable iron, which contributes to covering toddlers´ requirements of this micronutrient.

  12. Effects of Citric and Lactic Acid on the Reduction of Deoxynivalenol and Its Derivatives in Feeds

    Directory of Open Access Journals (Sweden)

    Elke Humer

    2016-09-01

    Full Text Available Exposure to mycotoxin-contaminated feeds represents a serious health risk. This has necessitated the need for the establishment of practical methods for mycotoxin decontamination. This study investigated the effects of citric acid (CA and lactic acid (LA on common trichothecene mycotoxins in feeds contaminated with Fusarium mycotoxins. Contaminated feed samples were processed either with 5% CA or 5% LA solutions in a ratio of 1:1.2 (w/v for 5, 24, or 48 h, and analyzed for multiple mycotoxin metabolites using a liquid chromatography–tandem mass spectrometric method. The analyses showed that treating the feed with CA and LA lowered the concentration of deoxynivalenol (DON, whereby 5% LA lowered the original DON concentration in the contaminated feed samples by half, irrespective of the processing time. Similar lowering effects were observed for the concentrations of 15Ac-DON, 5-hydroxyculmorin, and sambucinol. The concentration of nivalenol was only lowered by the LA treatment. In contrast, CA and LA treatments showed no or only small effects on the concentration of several mycotoxins and their derivatives, including zearalenone, fumonisins, and culmorin. In conclusion, the present results indicate that the use of 5% solutions of LA and CA might reduce the concentration of common trichothecene mycotoxins, especially DON and its derivate 15Ac-DON. However, further research is required to determine the effect on overall toxicity and to identify the underlying mechanisms.

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

    Science.gov (United States)

    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 (YCA) 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.

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

    Science.gov (United States)

    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 (Pcitric 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.

  15. Citric acid enhances the phytoextraction of manganese and plant growth by alleviating the ultrastructural damages in Juncus effusus L

    Energy Technology Data Exchange (ETDEWEB)

    Najeeb, U.; Xu, L.; Ali, Shafaqat [Institute of Crop Science, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310029 (China); Jilani, Ghulam, E-mail: jilani@uaar.edu.pk [Department of Soil Science, Pir Mehr Ali Shah Arid Agriculture University, Rawalpindi, Punjab 46300 (Pakistan); Gong, H.J. [Institute of Crop Science, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310029 (China); Shen, W.Q. [The University of Nottingham at Ningbo, Ningbo 315100 (China); Zhou, W.J., E-mail: wjzhou@zju.edu.cn [Institute of Crop Science, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310029 (China)

    2009-10-30

    Chelate-assisted phytoextraction by high biomass producing plant species enhances the removal of heavy metals from polluted environments. In this regard, Juncus effusus a wetland plant has great potential. This study evaluated the effects of elevated levels of manganese (Mn) on the vegetative growth, Mn uptake and antioxidant enzymes in J. effusus. We also studied the role of citric acid and EDTA on improving metal accumulation, plant growth and Mn toxicity stress alleviation. Three-week-old plantlets of J. effusus were subjected to various treatments in the hydroponics as: Mn (50, 100 and 500 {mu}M) alone, Mn (500 {mu}M) + citric acid (5 mM), and Mn (500 {mu}M) + EDTA (5 mM). After 2 weeks of treatment, higher Mn concentrations significantly reduced the plant biomass and height. Both citric acid and EDTA restored the plant height as it was reduced at the highest Mn level. Only the citric acid (but not EDTA) was able to recover the plant biomass weight, which was also obvious from the microscopic visualization of mesophyll cells. There was a concentration dependent increase in Mn uptake in J. effusus plants, and relatively more deposition in roots compared to aerial parts. Although both EDTA and citric acid caused significant increase in Mn accumulation; however, the Mn translocation was enhanced markedly by EDTA. Elevated levels of Mn augmented the oxidative stress, which was evident from changes in the activities of antioxidative enzymes in plant shoots. Raised levels of lipid peroxidation and variable changes in the activities of antioxidant enzymes were recorded under Mn stress. Electron microscopic images revealed several modifications in the plants at cellular and sub-cellular level due to the oxidative damage induced by Mn. Changes in cell shape and size, chloroplast swelling, increased number of plastoglobuli and disruption of thylakoid were noticed. However, these plants showed a high degree of tolerance against Mn toxicity stress, and it removed

  16. Improved Cycling Performance of a Si Nanoparticle Anode Utilizing Citric Acid as a Surface-Modifying Agent.

    Science.gov (United States)

    Nguyen, Cao Cuong; Seo, Daniel M; Chandrasiri, K W D K; Lucht, Brett L

    2017-09-19

    Citric acid and its analogues have been investigated as surface-modifying agents for Si nanoparticle anodes using electrochemical cycling, attenuated total reflectance infrared (ATR IR), and X-ray photoelectron spectroscopy (XPS). A Si nanoparticle anode prepared with citric acid (CA) has better capacity retention than one containing 1,2,3,4-butanetetracarboxylic acid (BA), but both electrodes outperform Si-PVDF. The Si-CA anode has an initial specific capacity of 3530 mA h/g and a first cycle efficiency of 82%. Surprisingly, the Si-CA electrode maintains a high specific capacity of ∼2200 mA h/g after 250 cycles, corresponding to 64% capacity retention, which is similar to the Si prepared with long-chain poly(acrylic acid) (PAA). On the contrary, the silicon electrode prepared with PVDF has a fast capacity fade and retains only 980 mA h/g after 50 cycles. The IR and XPS data show that the Si-CA electrode has an SEI composed primarily of lithium citrate during the first 50 cycles, resulting from the electrochemical reduction of citric acid. Only low concentrations of electrolyte reduction products are observed. The lithium citrate layer derived from CA stabilizes the silicon surface and suppresses electrolyte reduction, which likely contributes to the enhanced cycling performance of the Si nanoparticle anode.

  17. Effect of citric acid dosage and sintered temperature on the composition, morphology and electrochemical properties of lithium vanadium oxide prepared by a sol–gel method

    Science.gov (United States)

    Zhong, C. R.; Su, X. J.; Hou, G. L.; Liu, Z. H.; Yu, F. S.; Bi, S.; Li, H.

    2017-03-01

    A lithium vanadium oxide cathode material was synthesized via sol-gel processing using citric acid as the chelating agent. Different dosage of citric acid and sintered temperature were introduced to investigate their effects on the products composition, morphology and electrochemical properties. The results showed that the V2O3 yield was inhibited and the crystallization of grain was accelerated with the increasing dosage of citric acid. Furthermore, V2O3 was oxidized to LiV3O8 and Li0.3V2O5 with the increase of sintered temperature.

  18. Role of different additives and metallic micro minerals on the enhanced citric acid production by Aspergillus niger MNNG-115 using different carbohydrate materials.

    Science.gov (United States)

    Ali, Sikander; Haq, Ikram-ul

    2005-01-01

    The present investigation deals with the promotry effect of different additives and metallic micro minerals on citric acid production by Aspergillus niger MNNG-115 using different carbohydrate materials. For this, sugar cane bagasse was fortified with sucrose salt medium. Ethanol and coconut oil at 3.0% (v/w) level increased citric acid productivity. Fluoroacetate at a concentration of 1.0 mg/ml bagasse enhanced the yield of citric acid significantly. However, the addition of ethanol and fluoroacetate after 6 h of growth gave the maximum conversion of available sugar to citric acid. In another study, influence of some metallic micro-minerals viz. copper sulphate, molybdenum sulphate, zinc sulphate and cobalt sulphate on microbial synthesis of citric acid using molasses medium was also carried out. It was found that copper sulphate and molybdenum sulphate remarkably enhanced the production of citric acid while zinc sulphate was not so effective. However, cobalt sulphate was the least effective for microbial biosynthesis of citric acid under the same experimental conditions. In case of CuSO(4), the strain of Aspergillus niger MNNG-115 showed enhanced citric productivity with experimental (9.80%) over the control (7.54%). In addition, the specific productivity of the culture at 30 ppm CuSO(4) (Q(p) = 0.012a g/g cells/h) was several folds higher than other all other concentrations. All kinetic parameters including yield coefficients and volumetric rates revealed the hyper productivity of citric acid by CuSO(4) using blackstrap molasses as the basal carbon source.

  19. In vitro pharmacokinetics of anti-psoriatic fumaric acid esters

    NARCIS (Netherlands)

    N.H.R. Litjens (Nicolle); E. van Strijen (Elizabeth); C. van Gulpen (Co); H. Mattie (Herman); J.T. van Dissel (Jaap); H.B. Thio (Bing); P.H. Nibbering (Peter)

    2004-01-01

    textabstractBackground: Psoriasis is a chronic inflammatory skin disease that can be successfully treated with a mixture of fumaric acid esters (FAE) formulated as enteric-coated tablets for oral use. These tablets consist of dimethylfumarate (DMF) and salts of monoethylfumarate (MEF) and its main b

  20. New bis(alkythio) fatty acid methyl esters

    Science.gov (United States)

    The addition reaction of dimethyl disulfide (DMDS) to mono-unsaturated fatty acid methyl esters is well-known for analytical purposes to determine the position of double bonds by mass spectrometry. In this work, the classical iodine-catalyzed reaction is expanded to other dialkyl disulfides (RSSR), ...

  1. Synthesis and insecticidal activities of new pyrethroid acid oxime ester derivatives

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A series of compounds containing oxime-ester linkage in place of the ester linkage in pyrethroid ester are designed and prepared. Bioassay data of insecticidal activities of these compounds on Ostrinia nubilalis (H.) and Culex pipines (L.) are presented. Among them 4-dimethyaminobenzaldehyde oxime ester of 2,2,3,3-tetramethylcyclopropanecarboxylic acid and 4-dimethyamino benzaldehyde oxime ester of cyclopropanecarboxylic acid are found to be potent insecticide against Ostrinia nubilalis (H.). Structure-activity relationship of the compounds is discussed.

  2. Improved cadmium uptake and accumulation in the hyperaccumulator Sedum alfredii:the impact of citric acid and tartaric acid

    Institute of Scientific and Technical Information of China (English)

    Ling-li LU; Sheng-ke TIAN; Xiao-e YANG; Hong-yun PENG; Ting-qiang LI

    2013-01-01

    The elucidation of a natural strategy for metal hyperaccumulation enables the rational design of technologies for the clean-up of metal-contaminated soils.Organic acid has been suggested to be involved in toxic metallic element tolerance,translocation,and accumulation in plants.The impact of exogenous organic acids on cadmium(Cd)uptake and translocation in the zinc(Zn)/Cd co-hyperaccumulator Sedum alfredii was investigated in the present study.By the addition of organic acids,short-term(2 h)root uptake of 109Cd increased significantly,and higher 109Cd contents in roots and shoots were noted 24 h after uptake,when compared to controls.About 85% of the 109Cd taken up was distributed to the shoots in plants with citric acid(CA)treatments,as compared with 75% within controls.No such effect was observed for tartaric acid(TA).Reduced growth under Cd stress was significantly alleviated by low CA.Long-term application of the two organic acids both resulted in elevated Cd in plants,but the effects varied with exposure time and levels.The results imply that CA may be involved in the processes of Cd uptake,translocation and tolerance in S.alfredii,whereas the impact of TA is mainly on the root uptake of Cd.

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

    Science.gov (United States)

    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.

  4. Demineralization of root canal dentine with EDTA and citric acid in different concentrations, pH and application times

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    Mr.Sc. Nexhmije Ajeti

    2011-12-01

    Full Text Available Abstract The aims of the study are: 1. Determination of the amount of extracted Ca ions from den-tine using 17% and 10% EDTA, at pH 7 and pH 9. 2. Determination of the amount of extracted Ca ions from  den-tine using citric acid 5% and 1%, at pH 7 and pH 9.  Methodology 30 extracted, single rooted, human teeth were tested. Their crowns were sectioned at CEJ using diamond disks. The root canals were manually prepared with K-files #50-60. After each instrument 2.5 ml of 5.25% NaOCl was used and 0.9 NaCl as final irrigation. All teeth were longitudinally sectioned and 8 samples of dentine taken from each sample. EDTA 10% and 17 % and citric acid 1% and 5% in neutral and alkaline pH were used.  Each sample was immersed in acid and then exposure time was evaluated after 1, 5, 10, 15 and 25 min. The release rate of calcium ions from root dentine was evaluated by atomic absorption spectrometer.  Results There were significant differences in the amount of extracted Ca by citric acid 1% and 5% or EDTA 10% and 17% in human teeth.  Conclusions It may be concluded that EDTA is a better chelating agent than citric acid. The decalcifying activity of these solutions is related to the duration of exposure, pH and their concentrations.

  5. Transferable force field for carboxylate esters: application to fatty acid methylic ester phase equilibria prediction.

    Science.gov (United States)

    Ferrando, Nicolas; Lachet, Véronique; Boutin, Anne

    2012-03-15

    In this work, a new transferable united-atoms force field for carboxylate esters is proposed. All Lennard-Jones parameters are reused from previous parametrizations of the AUA4 force field, and only a unique set of partial electrostatic charges is introduced for the ester chemical function. Various short alkyl-chain esters (methyl acetate, ethyl acetate, methyl propionate, ethyl propionate) and two fatty acid methylic esters (methyl oleate and methyl palmitate) are studied. Using this new force field in Monte Carlo simulations, we show that various pure compound properties are accurately predicted: saturated liquid densities, vapor pressures, vaporization enthalpies, critical properties, liquid-vapor surface tensions. Furthermore, a good accuracy is also obtained in the prediction of binary mixture pressure-composition diagrams, without introducing empirical binary interaction parameters. This highlights the transferability of the proposed force field and gives the opportunity to simulate mixtures of industrial interest: a demonstration is performed through the simulation of the methyl oleate + methanol mixture involved in the purification sections of biodiesel production processes.

  6. 76 FR 7703 - 1,4-Benzenedicarboxylic Acid, Dimethyl Ester, Polymer With 1,4-Butanediol, Adipic Acid, and...

    Science.gov (United States)

    2011-02-11

    ... AGENCY 40 CFR Part 180 1,4-Benzenedicarboxylic Acid, Dimethyl Ester, Polymer With 1,4- Butanediol, Adipic... from the requirement of a tolerance for residues of 1,4-benzenedicarboxylic acid, dimethyl ester... residues of 1,4-benzenedicarboxylic acid, dimethyl ester, polymer with 1,4-butanediol, adipic acid,...

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  9. Fatty acid methyl esters production: chemical process variables

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    Paulo César Narváez Rincón

    2010-06-01

    Full Text Available The advantages of fatty acid methyl esters as basic oleochemicals over fatty acids, the seventies world energy crisis and the use of those oleochemicals as fuels, have increased research interest on fats and oils trans-esterification. In this document, a review about basic aspects, uses, process variables and problems associated to the production process of fatty acid methyl esters is presented. A global view of recent researches, most of them focused in finding a new catalyst with same activity as the alcohol-soluble hydroxides (NaOH, KOH, and suitable to be used in transforming fats and oils with high levels of free fatty acids and water avoiding separation problems and reducing process costs, is also discussed.

  10. Hydrometallurgical process for the recovery of metal values from spent lithium-ion batteries in citric acid media.

    Science.gov (United States)

    Chen, Xiangping; Zhou, Tao

    2014-11-01

    In this paper, a hydrometallurgical process has been proposed to recover valuable metals from spent lithium-ion batteries in citric acid media. Leaching efficiencies as high as 97%, 95%, 94%, and 99% of Ni, Co, Mn, and Li were achieved under the optimal leaching experimental conditions of citric acid concentration of 2 mol L(-1), leaching temperature of 80 °C, leaching time of 90 min, liquid-solid ratio of 30 ml g(-1), and 2 vol. % H2O2. For the metals recovery process, nickel and cobalt were selectively precipitated by dimethylglyoxime reagent and ammonium oxalate sequentially. Then manganese was extracted by Na-D2EHPA and the manganese-loaded D2EHPA was stripped with sulfuric acid. The manganese was recovered as MnSO4 in aqueous phase and D2EHPA could be reused after saponification. Finally, lithium was precipitated by 0.5 mol L(-1) sodium phosphate. Under their optimal conditions, the recovery percentages of Ni, Co, Mn, and Li can reach 98%, 97%, 98%, and 89%, respectively. This is a relatively simple route in which all metal values could be effectively leached and recovered in citric acid media.

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

    Science.gov (United States)

    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 (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.

  12. Aconitase is the main functional target of aging in the citric acid cycle of kidney mitochondria from mice.

    Science.gov (United States)

    Yarian, Connie S; Toroser, Dikran; Sohal, Rajindar S

    2006-01-01

    The activities of the citric acid cycle enzymes were determined in mitochondria isolated from kidneys of relatively young, middle age, and old mice. Aconitase exhibited the most significant decrease in activity with age. The activity of alpha-ketoglutarate dehydrogenase exhibited a modest decrease in activity, while NADP(+)-isocitrate dehydrogenase (NADP(+)-ICD) activity increased moderately with age. Activities of citrate synthase, NAD(+)-isocitrate dehydrogenase (NAD(+)-ICD), succinyl-CoA synthetase (SCS), succinate dehydrogenase (SD), fumarase (FUM), and malate dehydrogenase (MD) were not affected. The molar ratio of the intra-mitochondrial redox indicator, NADPH:NADP(+), was higher in young compared to old animals, while the NADH:NAD(+) molar ratio remained unchanged. It is suggested that an age-related decrease in aconitase activity along with relatively subtle alterations in activities of some other citric acid cycle enzymes are likely to contribute to a decline in the overall efficiency of mitochondrial bioenergetics. The biological consequences of such alterations include age-related fluctuations in the citric acid cycle intermediates, which are precursors of protein synthesis, activators of fatty acid synthesis, and can also act as ligands for orphan G-protein coupled receptors.

  13. The relationship between fatty acid and citric acid concentrations in milk from Holstein cows uring the period of negative energy balance

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    Jaromir DUCHÁČEK

    2012-12-01

    Full Text Available The objective of this study was to determine the relationship between body condition score changes and the dynamics of energy balance indicators - fatty acid and citric acid contents - in milk during a early part of lactation. In addition, the relationship between these two indicators was also evaluated. A total of 27 Holstein cows that calved within three consecutive weeks were included in the analysis. During the first 17 weeks of lactation, milk samples were collected at a weekly interval and body condition score was assessed once a month. Statistical analyses were performed using Microsoft Office Excel and the procedures MEANS and CORR of SAS 9.1. Trend functions describing the development of fatty acid and citric acid contents explained 67.67 to 92.19 % of their variability. Similar relationships between fatty acid and citric acid contents and the changes in body condition score during the first three months of lactation were observed. In addition, a similar decreasing tendency was also determined for the contents of both the dependent variables in this period. Significant correlations (P<0.01 – 0.001 were calculated (r = 0.51 – 0.74 for lactation weeks 6 and 7, thus before the subsequent decrease of body condition score by 0.2 points between weeks 8 and 12 after parturition. The results indicate the possibility of using the contents of fatty acids and citric acid as indicators of energy balance in dairy cows. The results also confirm the relationships between these indicators and emphasise the importance of proper herd management with respect to body condition score changes and the contents of fatty acids and citric acid in milk.

  14. Inhibition of hypoxia-inducible factor (HIF) hydroxylases by citric acid cycle intermediates: possible links between cell metabolism and stabilization of HIF.

    Science.gov (United States)

    Koivunen, Peppi; Hirsilä, Maija; Remes, Anne M; Hassinen, Ilmo E; Kivirikko, Kari I; Myllyharju, Johanna

    2007-02-16

    The stability and transcriptional activity of the hypoxia-inducible factors (HIFs) are regulated by two oxygen-dependent events that are catalyzed by three HIF prolyl 4-hydroxylases (HIF-P4Hs) and one HIF asparaginyl hydroxylase (FIH). We have studied possible links between metabolic pathways and HIF hydroxylases by analyzing the abilities of citric acid cycle intermediates to inhibit purified human HIF-P4Hs and FIH. Fumarate and succinate were identified as in vitro inhibitors of all three HIF-P4Hs, fumarate having K(i) values of 50-80 microM and succinate 350-460 microM, whereas neither inhibited FIH. Oxaloacetate was an additional inhibitor of all three HIF-P4Hs with K(i) values of 400-1000 microM and citrate of HIF-P4H-3, citrate being the most effective inhibitor of FIH with a K(i) of 110 microM. Culturing of cells with fumarate diethyl or dimethyl ester, or a high concentration of monoethyl ester, stabilized HIF-1alpha and increased production of vascular endothelial growth factor and erythropoietin. Similar, although much smaller, changes were found in cultured fibroblasts from a patient with fumarate hydratase (FH) deficiency and upon silencing FH using small interfering RNA. No such effects were seen upon culturing of cells with succinate diethyl or dimethyl ester. As FIH was not inhibited by fumarate, our data indicate that the transcriptional activity of HIF is quite high even when binding of the coactivator p300 is prevented. Our data also support recent suggestions that the increased fumarate and succinate levels present in the FH and succinate dehydrogenase-deficient tumors, respectively, can inhibit the HIF-P4Hs with consequent stabilization of HIF-alphas and effects on tumor pathology.

  15. Shelf life of minimally processed pineapples treated with ascorbic and citric acids

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    Lucimara Rogéria Antoniolli

    2012-01-01

    Full Text Available The purpose of this research was to determine the shelf life of minimally processed (MP 'Pérola' pineapples treated with ascorbic acid (AA and citric acid (CA based on physical, chemical, sensorial and microbiological attributes. Slices were dipped into drinking water (control or combined solutions of AA:CA (% (1.0:0.5 and 1.0:1.0 with sodium hypochlorite (NaClO 20 mg L-1 for 30 seconds. The samples were conditioned in polyethylene terephtalate packages and stored at 4±1 °C per 13 days. The low peroxidase activity in the slices treated with antioxidant combinations was related to low pH values observed in these samples. The treatments 1.0:0.5 and 1.0:1.0 (AA:CA, % favored maintenance of the initial a* values and avoided the pulp browning. The ascorbic acid increased more than double on the 2nd day in the treated slices. By the 4th day the CO2 values suggested a higher respiratory activity in the slices treated with anti-browning compounds. The antioxidant treatments did not produce detectable residual flavors in the MP pineapple. Regardless of microbiological safety during the 13 days of cold storage, the control slices can be kept by 6 days, afterwards the color and dehydration become strong enough to affect the appearance. On the other hand, MP 'Pérola' pineapples treated with 1.0:0.5 (AA:CA, % and NaClO (20 mg L-1 can be stored for 8 days at 4±1 ºC, which represents the extension of the shelf life in 2 days. After this period the overripe odor starts to develop.

  16. Vibrational Study and Force Field of the Citric Acid Dimer Based on the SQM Methodology

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    Laura Cecilia Bichara

    2011-01-01

    Full Text Available We have carried out a structural and vibrational theoretical study for the citric acid dimer. The Density Functional Theory (DFT method with the B3LYP/6-31G∗ and B3LYP/6-311++G∗∗ methods have been used to study its structure and vibrational properties. Then, in order to get a good assignment of the IR and Raman spectra in solid phase of dimer, the best fit possible between the calculated and recorded frequencies was carry out and the force fields were scaled using the Scaled Quantum Mechanic Force Field (SQMFF methodology. An assignment of the observed spectral features is proposed. A band of medium intensity at 1242 cm−1 together with a group of weak bands, previously not assigned to the monomer, was in this case assigned to the dimer. Furthermore, the analysis of the Natural Bond Orbitals (NBOs and the topological properties of electronic charge density by employing Bader's Atoms in Molecules theory (AIM for the dimer were carried out to study the charge transference interactions of the compound.

  17. Citric acid based durable and sustainable flame retardant treatment for lyocell fabric.

    Science.gov (United States)

    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.

  18. THERMOPLASTIC STARCH FILMS. INFLUENCE OF INCORPORATION OF HYDROXYPROPYL-METHYL-CELLULOSE AND CITRIC ACID

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    Rodrigo Ortega Toro

    2014-12-01

    Full Text Available The aim of this work was to analyze the influence of citric acid (CA and hydroxypropyl-methyl-cellulose (HPMC addition in thermoplastic starch films obtained by compression-molding. Two ratios of HPMC- starch (10% and 20% were considered while starch: CA ratio was of 1: 0,01. The films were characterized as to micro- and nano-structure using Scanning Electron Microscopy (SEM and X-ray diffraction. Further, the water solubility, CA linked, mechanical and thermal properties were characterized. The starch-HPMC films showed phase separation although the glass transition analysis showed partial miscibility of the starch and HPMC which is accentuated with the addition of CA. The incorporation of HPMC and CA promoted the decrease of water vapor permeability and a slight increase in the oxygen permeability. The CA addition resulted in an increase of the elasticity modulus and decrease in the extensibility of films, which agrees with the cross-linking effect. The optical properties show a decrease in the material compactness with the CA presence causing higher film transparency

  19. Synthesis of citric acid functionalized magnetic graphene oxide coated corn straw for methylene blue adsorption.

    Science.gov (United States)

    Ge, Heyi; Wang, Cuicui; Liu, Shanshan; Huang, Zhen

    2016-12-01

    The citric acid functionalized magnetic graphene oxide coated corn straw (CA-mGOCS) as a new adsorbent was synthesized in this work for the elimination of methylene blue (MB) from waste water. The as-prepared CA-mGOCS was tested by SEM, FTIR, XRD, Roman spectrum, TGA, particle size analyzer, BET and magnetic properties analyzer. Some factors affecting adsorption removal efficiency were explored. As a result, the addition of 5g CS (CA-mGO5CS) had the better adsorption performance than other adsorbents. The pseudo-second-order model and the Freundlich described the adsorption behavior well. The equilibrium adsorption capacity was 315.5mgg(-1) for MB at pH=12 and 298k. The electrostatic incorporation as well as hydrophobic interactions between CA-mGO5CS and MB determined the favourable adsorption property. Besides, the thermodynamic studies results ΔGadsorption was a spontaneous, exothermic and randomness decrease process. Finally, reusability studies imply that CA-mGO5CS has an excellent reproducibility.

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

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    Gurparkash Singh Chahal

    2014-01-01

    Full Text Available 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.

  1. Effect of Trace Elements on Citric Acid Fermentation by Aspergillus niger

    Science.gov (United States)

    Sánchez-Marroquín, A.; Carreño, R.; Ledezma, M.

    1970-01-01

    Citric acid yields of 98.7% (sugar consumption basis) were reached in shaker flasks with mutant UV-ET-71-15 of Aspergillus niger in a resin-treated sucrose medium of the following composition (g/100 ml): sucrose, 14.0; NH4NO3, 0.20; KH2PO4, 0.10; MgSO4·7H2O, 0.025; and (mg/liter): FeSO4, 0.15 to 0.75; ZnSO4, 0.10; and CuSO4, 0.01. Yields of 75% were obtained in medium with resin-treated clarified syrup and 68% with ferrocyanide-treated blackstrap molasses. Optimal conditions included selection of appropriate pellets as inoculum at 3%, pH of 4.5, temperature at 30 C, agitation at 250 rev/min, and fermentation time of 8 days. The mutant tolerated high concentrations of trace elements. PMID:5492439

  2. The Viability of a Nonenzymatic Reductive Citric Acid Cycle Kinetics and Thermochemistry

    Science.gov (United States)

    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.

  3. Identification and physicochemical characterization of caffeine-citric acid co-crystal polymorphs.

    Science.gov (United States)

    Mukaida, Makoto; Watanabe, Yuka; Sugano, Kiyohiko; Terada, Katsuhide

    2015-11-15

    The purpose of the present study was to identify a new caffeine-citric acid co-crystal (CA-CI) polymorph and characterize three CA-CI polymorphs. The stability order among the three CA-CI polymorphs was also determined. One new and two known CA-CI polymorphs were prepared by the liquid-assisted grinding method or the slurry methods. The three CA-CIs were then identified and characterized by powder X-ray diffraction (PXRD), thermal analysis, IR spectroscopy, Raman spectroscopy, and dynamic vapor sorption (DVS). The stability order of the CA-CIs was determined by the slurry conversion method. Each CA-CI showed distinct PXRD, IR, Raman, and DVS data. The melting points of CA-CIs were 131°C (a new form, Form III), 141°C (Form I), and 160°C (Form II). The order of thermodynamic stability was CA-CI Form II>CA-CI Form I>CA-CI Form III. CA-CI Forms I and II were relatively stable against humidity compared to CA, CI and CA-CI Form III.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  6. The viability of a nonenzymatic reductive citric acid cycle--kinetics and thermochemistry.

    Science.gov (United States)

    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.

  7. Synthesis of Li2FeSiO4/C composite by sol-gel citric acid assisted method

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    Milović Miloš D.

    2016-01-01

    Full Text Available This paper describes a procedure for the synthesis of the composite Li2FeSiO4/C by sol-gel method using citric acid as a chelating agent; the resulting gel precursor was thermally treated in a slightly reductive atmosphere of nitrogen with five percent of hydrogen, whereupon the in situ decomposition of citric acid to carbon occurs during formation of the Li2FeSiO4. The obtained nanocrystalline powder (with mean crystallite size of 27nm crystallized in the P21/n space group as confirmed by X-ray diffractometry. The morphology of the powder was examined by scanning electron microscopy which revealed a wide distribution of particles by size, from 100 to 500 nm. The material has been tested as cathode in lithium-ion cell and exhibits high efficiency and almost theoretical capacity.

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

    Science.gov (United States)

    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

  9. Production of tartrates by cyanide-mediated dimerization of glyoxylate: a potential abiotic pathway to the citric acid cycle.

    Science.gov (United States)

    Butch, Christopher; Cope, Elizabeth D; Pollet, Pamela; Gelbaum, Leslie; Krishnamurthy, Ramanarayanan; Liotta, Charles L

    2013-09-11

    An abiotic formation of meso- and DL-tartrates in 80% yield via the cyanide-catalyzed dimerization of glyoxylate under alkaline conditions is demonstrated. A detailed mechanism for this conversion is proposed, supported by NMR evidence and (13)C-labeled reactions. Simple dehydration of tartrates to oxaloacetate and an ensuing decarboxylation to form pyruvate are known processes that provide a ready feedstock for entry into the citric acid cycle. While glyoxylate and high hydroxide concentration are atypical in the prebiotic literature, there is evidence for natural, abiotic availability of each. It is proposed that this availability, coupled with the remarkable efficiency of tartrate production from glyoxylate, merits consideration of an alternative prebiotic pathway for providing constituents of the citric acid cycle.

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

    Directory of Open Access Journals (Sweden)

    Paula González Seligra

    2016-06-01

    Full Text Available 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.

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

    Science.gov (United States)

    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

  12. Transformation of Unsaturated Fatty Acids/Esters to Corresponding Keto Fatty Acids/Esters by Aerobic Oxidation with Pd(II)/Lewis Acid Catalyst.

    Science.gov (United States)

    Senan, Ahmed M; Zhang, Sicheng; Zeng, Miao; Chen, Zhuqi; Yin, Guochuan

    2017-08-16

    Utilization of renewable biomass to partly replace the fossil resources in industrial applications has attracted attention due to the limited fossil feedstock with the increased environmental concerns. This work introduced a modified Wacker-type oxidation for transformation of unsaturated fatty acids/esters to the corresponding keto fatty acids/esters, in which Cu(2+) cation was replaced with common nonredox metal ions, that is, a novel Pd(II)/Lewis acid (LA) catalyst. It was found that adding nonredox metal ions can effectively promote Pd(II)-catalyzed oxidation of unsaturated fatty acids/esters to the corresponding keto fatty acids/esters, even much better than Cu(2+), and the promotional effect is highly dependent on the Lewis acidity of added nonredox metal ions. The improved catalytic efficiency is attributed to the formation of heterobimetallic Pd(II)/LA species, and the oxidation mechanism of this Pd(II)/LA catalyst is also briefly discussed.

  13. Methods of refining and producing dibasic esters and acids from natural oil feedstocks

    Energy Technology Data Exchange (ETDEWEB)

    Snead, Thomas E; Cohen, Steven A; Gildon, Demond L

    2015-04-07

    Methods are provided for refining natural oil feedstocks and producing dibasic esters and/or dibasic acids. The methods comprise reacting a terminal olefin with an internal olefin in the presence of a metathesis catalyst to form a dibasic ester and/or dibasic acid. In certain embodiments, the olefin esters are formed by reacting the feedstock in the presence of a metathesis catalyst under conditions sufficient to form a metathesized product comprising olefins and esters, separating the olefins from the esters in the metathesized product, and transesterifying the esters in the presence of an alcohol to form a transesterified product having olefin esters.

  14. Methods of refining and producing dibasic esters and acids from natural oil feedstocks

    Energy Technology Data Exchange (ETDEWEB)

    Snead, Thomas E.; Cohen, Steven A.; Gildon, Demond L.

    2016-03-15

    Methods are provided for refining natural oil feedstocks and producing dibasic esters and/or dibasic acids. The methods comprise reacting a terminal olefin with an internal olefin in the presence of a metathesis catalyst to form a dibasic ester and/or dibasic acid. In certain embodiments, the olefin esters are formed by reacting the feedstock in the presence of a metathesis catalyst under conditions sufficient to form a metathesized product comprising olefins and esters, separating the olefins from the esters in the metathesized product, and transesterifying the esters in the presence of an alcohol to form a transesterified product having olefin esters.

  15. Methods of refining and producing dibasic esters and acids from natural oil feedstocks

    Science.gov (United States)

    Snead, Thomas E; Cohen, Steven A; Gildon, Demond L

    2015-04-07

    Methods are provided for refining natural oil feedstocks and producing dibasic esters and/or dibasic acids. The methods comprise reacting a terminal olefin with an internal olefin in the presence of a metathesis catalyst to form a dibasic ester and/or dibasic acid. In certain embodiments, the olefin esters are formed by reacting the feedstock in the presence of a metathesis catalyst under conditions sufficient to form a metathesized product comprising olefins and esters, separating the olefins from the esters in the metathesized product, and transesterifying the esters in the presence of an alcohol to form a transesterified product having olefin esters.

  16. Encapsulating fatty acid esters of bioactive compounds in starch

    Science.gov (United States)

    Lay Ma, Ursula Vanesa

    Interest in the use of many bioactive compounds in foods is growing in large part because of the apparent health benefits of these molecules. However, many of these compounds can be easily degraded during processing, storage, or their passage through the gastrointestinal tract before reaching the target site. In addition, they can be bitter, acrid, or astringent, which may negatively affect the sensory properties of the product. Encapsulation of these molecules may increase their stability during processing, storage, and in the gastrointestinal tract, while providing controlled release properties. The ability of amylose to form inclusion complexes and spherulites while entrapping certain compounds has been suggested as a potential method for encapsulation of certain molecules. However, complex formation and spherulitic crystallization are greatly affected by the type of inclusion molecules, type of starch, and processing conditions. The objectives of the present investigation were to: (a) study the effect of amylose, amylopectin, and intermediate material on spherulite formation and its microstructure; (b) investigate the formation of amylose and high amylose starch inclusion complexes with ascorbyl palmitate, retinyl palmitate, and phytosterol esters; (c) evaluate the ability of spherulites to form in the presence of fatty acid esters and to entrap ascorbyl palmitate, retinyl palmitate, and phytosterol esters; and (d) evaluate the effect of processing conditions on spherulite formation and fatty acid ester entrapment. Higher ratios of linear to branched molecules resulted in the formation of more and rounder spherulites with higher heat stability. In addition to the presence of branches, it appears that spherulitic crystallization is also affected by other factors, such as degree of branching, chain length, and chain length distribution. Amylose and Hylon VII starch formed inclusion complexes with fatty acid esters of ascorbic acid, retinol, or phytosterols

  17. Aconitase is the main functional target of aging in the citric acid cycle of kidney mitochondria from mice

    OpenAIRE

    Yarian, Connie S.; Toroser, Dikran; Sohal, Rajindar S.

    2005-01-01

    The activities of the citric acid cycle enzymes were determined in mitochondria isolated from kidneys of relatively young, middle age, and old mice. Aconitase exhibited the most significant decrease in activity with age. The activity of α-ketoglutarate dehydrogenase exhibited a modest decrease in activity, while NADP+-isocitrate dehydrogenase (NADP+-ICD) activity increased moderately with age. Activities of citrate synthase, NAD+-isocitrate dehydrogenase (NAD+-ICD), succinyl-CoA synthetase (S...

  18. Effect of EDTA, HCl, and citric acid on Ca salt removal from Asian (silver) carp scales prior to gelatin extraction.

    Science.gov (United States)

    Wang, Yan; Regenstein, Joe M

    2009-08-01

    Pretreatments with different chemicals at different concentrations to remove Ca compounds were studied to determine their effects on gelatin extraction from silver carp (Hypophthalmichthys molitrix) scales. During Ca removal with HCl, citric acid, and EDTA, all 3 chemicals were able to decalcify (>90%) scales; however, protein losses with EDTA were lower than with HCl and citric acid (P < 0.05), and protein losses with citric acid were lower than with HCl (P < 0.05). Ca removal with HCl yielded a solution where 4% to 5% of the protein was Hyp, with estimated gelatin losses from 0.9% to 2.5%. After 0.20 mol/L HCl was used for Ca removal, the extracted gelatin solution was 15.4% of the initial scales weight and gave a gel strength of 128 g. After using 1.2 g/L citric acid for Ca removal, the extracted gelatin solution was only 9% of the scales and the gel strength was 97 g. Using 0.20 mol/L EDTA for Ca removal gave a yield of 22% and a gel strength of 152 g. These data suggest that EDTA at 0.20 mol/L provides the best Ca removal with minimal collagen/gelatin removal (estimated gelatin loss was less than 0.013%) during the Ca removal step, and subsequently gave a high gelatin yield and gel strength. Fish gelatin has generally been extracted from fish skins and occasionally fish bones. This article focuses on removing the Ca compounds in fish scales and then producing fish gelatin with a good gel strength and yield. With further studies, this study may help the fish industry to have a new source of fish gelatin for food and pharmaceutical applications.

  19. Olodaterol attenuates citric acid-induced cough in naïve and ovalbumin-sensitized and challenged guinea pigs.

    Science.gov (United States)

    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 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 cough reflex, the mechanism underlying the pro-tussive property of indacaterol is not known.

  20. Oxidation of acetate through reactions of the citric acid cycle by Geobacter sulfurreducens in pure culture and in syntrophic coculture

    OpenAIRE

    2000-01-01

    Geobacter sulfurreducens strain PCA oxidized acetate to CO2 via citric acid cycle reactions during growth with acetate plus fumarate in pure culture, and with acetate plus nitrate in coculture with Wolinella succinogenes. Acetate was activated by succinyl-CoA:acetate CoA-transferase and also via acetate kinase plus phosphotransacetylase. Citrate was formed by citrate synthase. Soluble isocitrate and malate dehydrogenases reduced NADP+ and NAD+, respectively. Oxidation of 2-oxoglutarate was me...

  1. Coagulation of bitumen with kaolinite in aqueous solutions containing Ca2+, Mg2+ and Fe3+: effect of citric acid.

    Science.gov (United States)

    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.

  2. 40 CFR 721.3700 - Fatty acid, ester with styrenated phenol, ethylene oxide adduct.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Fatty acid, ester with styrenated... Significant New Uses for Specific Chemical Substances § 721.3700 Fatty acid, ester with styrenated phenol... chemical substance identified generically as fatty acid, ester with styrenated phenol, ethylene...

  3. 40 CFR 721.2900 - Substituted aminobenzoic acid ester (generic name).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Substituted aminobenzoic acid ester... Specific Chemical Substances § 721.2900 Substituted aminobenzoic acid ester (generic name). (a) Chemical... acid ester (PMN P-84-951) is subject to reporting under this section for the significant new...

  4. 40 CFR 721.3800 - Formaldehyde, condensated polyoxyethylene fatty acid, ester with styrenated phenol, ethylene...

    Science.gov (United States)

    2010-07-01

    ... polyoxyethylene fatty acid, ester with styrenated phenol, ethylene oxide adduct. 721.3800 Section 721.3800... Formaldehyde, condensated polyoxyethylene fatty acid, ester with styrenated phenol, ethylene oxide adduct. (a... generically as formaldehyde, condensated polyoxyethylene fatty acid, ester with styrenated phenol,...

  5. 75 FR 52269 - Acetic Acid Ethenyl Ester, Polymer With Oxirane; Tolerance Exemption

    Science.gov (United States)

    2010-08-25

    ...-2010-0429; FRL-8841-2] Acetic Acid Ethenyl Ester, Polymer With Oxirane; Tolerance Exemption AGENCY... from the requirement of a tolerance for residues of acetic acid ethenyl ester, polymer with oxirane... permissible level for residues of acetic acid ethenyl ester, polymer with oxirane on food or feed...

  6. 40 CFR 721.4250 - Hexanoic acid, 2-ethyl-, ethenyl ester.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Hexanoic acid, 2-ethyl-, ethenyl ester... Substances § 721.4250 Hexanoic acid, 2-ethyl-, ethenyl ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as hexanoic acid, 2-ethyl-, ethenyl ester...

  7. 78 FR 70878 - Octadecanoic Acid, 12-Hydroxy-, Homopolymer, Ester With 2-Methyloxirane Polymer With Oxirane...

    Science.gov (United States)

    2013-11-27

    ... AGENCY 40 CFR Part 180 Octadecanoic Acid, 12-Hydroxy-, Homopolymer, Ester With 2- Methyloxirane Polymer... residues of Octadecanoic Acid, 12-Hydroxy-, Homopolymer, Ester with 2-Methyloxirane Polymer with Oxirane... a maximum permissible level for residues of Octadecanoic Acid, 12-Hydroxy-, Homopolymer, Ester...

  8. 40 CFR 721.10064 - 2-Propenoic acid, 2-[2-(ethenyloxy)ethoxy]ethyl ester.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false 2-Propenoic acid, 2- ethyl ester. 721... Substances § 721.10064 2-Propenoic acid, 2- ethyl ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as 2-propenoic acid, 2- ethyl ester (PMN...

  9. 21 CFR 175.260 - Partial phosphoric acid esters of polyester resins.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Partial phosphoric acid esters of polyester resins... COMPONENTS OF COATINGS Substances for Use as Components of Coatings § 175.260 Partial phosphoric acid esters of polyester resins. Partial phosphoric acid esters of polyester resins identified in this section...

  10. 76 FR 8895 - Polymerized Fatty Acid Esters With Aminoalcohol Alkoxylates; Exemption From the Requirement of a...

    Science.gov (United States)

    2011-02-16

    ... AGENCY 40 CFR Part 180 Polymerized Fatty Acid Esters With Aminoalcohol Alkoxylates; Exemption From the... acid esters with aminoalcohol alkoxylates (PFAEAA) with a minimum number average molecular weight (in... tolerance for residues of polymerized fatty acid esters with aminoalcohol alkoxylates (PFAEAA); limited to...

  11. 40 CFR 721.8340 - Mono esters from 2- propenoic acid (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Mono esters from 2- propenoic acid... Specific Chemical Substances § 721.8340 Mono esters from 2- propenoic acid (generic). (a) Chemical... as mono esters from 2-propenoic acid (PMN P-01-85) is subject to reporting under this section for the...

  12. 40 CFR 721.6475 - Alkyl polycarboxylic acids, esters with ethoxylated fatty alcohols.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkyl polycarboxylic acids, esters... Significant New Uses for Specific Chemical Substances § 721.6475 Alkyl polycarboxylic acids, esters with... chemical substances identified generically as alkyl polycarboxylic acids, esters with ethoxylated fatty...

  13. 40 CFR 721.6110 - Alkyldi(alkyloxyhydroxypropyl) derivative, phosphoric acid esters, potassium salts.

    Science.gov (United States)

    2010-07-01

    ...) derivative, phosphoric acid esters, potassium salts. 721.6110 Section 721.6110 Protection of Environment...) derivative, phosphoric acid esters, potassium salts. (a) Chemical substance and significant new uses subject...) derivative, phosphoric acid esters, potassium salts (PMN P-91-818) is subject to reporting under this section...

  14. 21 CFR 573.640 - Methyl esters of higher fatty acids.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Methyl esters of higher fatty acids. 573.640... ANIMALS Food Additive Listing § 573.640 Methyl esters of higher fatty acids. The food additive methyl esters of higher fatty acids may be safely used in animal feeds in accordance with the...

  15. Green Synthesis of Acid Esters from Furfural via Stobbe Condensation

    Directory of Open Access Journals (Sweden)

    Shubhra Banerjee

    2013-01-01

    Full Text Available Solvent-free Stobbe condensation of furfural 1 with dimethyl succinate 2 under anhydrous conditions at room temperature using dry-solid potassium tertiary butoxide gave 3-carbomethoxy, 4-furyl-3-butenoic acid 3, which upon methylation followed by Stobbe condensation reaction with different aldehydes and/or ketones under anhydrous conditions at room temperature afforded substituted carbomethoxy acids 5a–f. These acid ester products were saponified to the corresponding dicarboxylic acids 6a–f which are useful in the synthesis of photochromic fulgides.

  16. Improving oxidative stability of olive oil: Incorporation of Spirulina and evaluation of its synergism with citric acid

    Directory of Open Access Journals (Sweden)

    N. Alavi

    2017-03-01

    Full Text Available The effects of different Spirulina concentrations used alone and in combination with citric acid on the oxidative stability of olive oil were assessed. The amounts of primary and secondary oxidation products produced in Spirulina samples were lower than that of the control. The improved oxidative stability indices of Spirulina samples with and without citric acid were in the range of 85.20–94.47% and 258.10–260.21%, respectively. In comparison with the control, Spirulina samples manifested significantly higher carotenoid and chlorophyll contents at the beginning and end of the storage period. The presence of these bioactive compounds results from the presence of Spirulina in the medium and can thus retard the oxidation of olive oil. A higher oxidative stability was reached using BHT in comparison with Spirulina samples. Furthermore, no synergistic action was observed in possible connections between citric acid and Spirulina. In conclusion, Spirulina can enhance oxidative stability and improve the shelf life of olive oil.

  17. The effect of nedocromil sodium, sodium cromoglycate and codeine phosphate on citric acid-induced cough in dogs.

    Science.gov (United States)

    Jackson, D. M.

    1988-01-01

    1. The effects of nedocromil sodium, sodium cromoglycate and codeine phosphate on citric acid-induced cough have been studied in conscious tracheostomised dogs. 2. Nedocromil sodium (approximately 15 mg given as an aerosol) and codeine phosphate (5 mg kg-1, i.v.) significantly increased the time to the first cough when dogs were challenged with citric acid aerosol. The mean number of coughs in the initial period of coughing fell after treatment of dogs with nedocromil sodium or with codeine phosphate, but this reduction in mean cough number was not statistically significant. 3. Neither sodium cromoglycate (approximately 15 mg given as an aerosol) nor saline had significant effect on a citric acid challenge. 4. It is concluded that nedocromil sodium, but not sodium cromoglycate, possesses an anti-tussive action that may result from inhibition of sensory nerve activity in the lung. Nedocromil sodium may prove useful in the treatment of unproductive cough in situations where the use of a centrally-acting antitussive is undesirable. PMID:2836011

  18. Metabolomic and mass isotopomer analysis of liver gluconeogenesis and citric acid cycle: II. Heterogeneity of metabolite labeling pattern.

    Science.gov (United States)

    Yang, Lili; Kasumov, Takhar; Kombu, Rajan S; Zhu, Shu-Han; Cendrowski, Andrea V; David, France; Anderson, Vernon E; Kelleher, Joanne K; Brunengraber, Henri

    2008-08-08

    In this second of two companion articles, we compare the mass isotopomer distribution of metabolites of liver gluconeogenesis and citric acid cycle labeled from NaH(13)CO(3) or dimethyl [1,4-(13)C(2)]succinate. The mass isotopomer distribution of intermediates reveals the reversibility of the isocitrate dehydrogenase + aconitase reactions, even in the absence of a source of alpha-ketoglutarate. In addition, in many cases, a number of labeling incompatibilities were found as follows: (i) glucose versus triose phosphates and phosphoenolpyruvate; (ii) differences in the labeling ratios C-4/C-3 of glucose versus (glyceraldehyde 3-phosphate)/(dihydroxyacetone phosphate); and (iii) labeling of citric acid cycle intermediates in tissue versus effluent perfusate. Overall, our data show that gluconeogenic and citric acid cycle intermediates cannot be considered as sets of homogeneously labeled pools. This probably results from the zonation of hepatic metabolism and, in some cases, from differences in the labeling pattern of mitochondrial versus extramitochondrial metabolites. Our data have implications for the use of labeling patterns for the calculation of metabolic rates or fractional syntheses in liver, as well as for modeling liver intermediary metabolism.

  19. Oxidation of acetate through reactions of the citric acid cycle by Geobacter sulfurreducens in pure culture and in syntrophic coculture.

    Science.gov (United States)

    Galushko, A S; Schink, B

    2000-11-01

    Geobacter sulfurreducens strain PCA oxidized acetate to CO2 via citric acid cycle reactions during growth with acetate plus fumarate in pure culture, and with acetate plus nitrate in coculture with Wolinella succinogenes. Acetate was activated by succinyl-CoA:acetate CoA-transferase and also via acetate kinase plus phosphotransacetylase. Citrate was formed by citrate synthase. Soluble isocitrate and malate dehydrogenases NADP+ and NAD+, respectively. Oxidation of 2-oxoglutarate was measured as benzyl viologen reduction and strictly CoA-dependent; a low activity was also observed with NADP+. Succinate dehydrogenase and fumarate ductase both were membrane-bound. Succinate oxidation was coupled to NADP+ reduction whereas fumarate reduction was coupled to NADPH and NADH Coupling of succinate oxidation to NADP+ or cytochrome(s) reduction required an ATP-dependent reversed electron transport. Net ATP synthesis proceeded exclusively through electron transport phosphorylation. During fumarate reduction, both NADPH and NADH delivered reducing equivalents into the electron transport chain, which contained a menaquinone. Overall, acetate oxidation with fumarate proceeded through an open loop of citric acid cycle reactions, excluding succinate dehydrogenase, with fumarate reductase as the key reaction for electron delivery, whereas acetate oxidation in the syntrophic coculture required the complete citric acid cycle.

  20. Efficacy of citric acid denture cleanser on the Candida albicans biofilm formed on poly(methyl methacrylate): effects on residual biofilm and recolonization process

    National Research Council Canada - National Science Library

    Faot, Fernanda; Cavalcanti, Yuri Wanderley; Mendonça e Bertolini, Martinna de; Pinto, Luciana de Rezende; da Silva, Wander José; Cury, Altair Antoninha Del Bel

    2014-01-01

    ...; 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...

  1. Citric acid production by solid-state fermentation on a semi-pilot scale using different percentages of treated cassava bagasse

    Directory of Open Access Journals (Sweden)

    F. C. Prado

    2005-12-01

    Full Text Available Citric acid is commercailly important product used in several industrial processes. Solid-state fermentation (SSF has become an alternative method for citric acid production using agro-industrial residues such as cassava bagasse (CB. Use of CB as substrate can avoid the environmental problems caused by its disposal in the environment. The aim of this work was to verify the effect of different percentages of gelatinized starch in CB on production of citric acid by SSF in horizontal drum and tray-type bioreactors. Gelatinization was used in order to make the starch structure more susceptible to consumption by the fungus. The best results (26.9 g/100g of dry CB were obtained in horizontal drum bioreactor using 100% gelatinized CB, although the tray-type bioreactor offers advantages and shows promise for large-scale citric acid production in terms of processing costs.

  2. C-Myc Induced Compensated Cardiac Hypertrophy Increases Free Fatty Acid Utilization for the Citric Acid Cycle

    Energy Technology Data Exchange (ETDEWEB)

    Olson, Aaron; Ledee, Dolena; Iwamoto, Kate; Kajimoto, Masaki; O' Kelly-Priddy, Colleen M.; Isern, Nancy G.; Portman, Michael A.

    2013-02-01

    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, 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 maintained

  3. Differential effects of heptanoate and hexanoate on myocardial citric acid cycle intermediates following ischemia-reperfusion.

    Science.gov (United States)

    Okere, Isidore C; McElfresh, Tracy A; Brunengraber, Daniel Z; Martini, Wenjun; Sterk, Joseph P; Huang, Hazel; Chandler, Margaret P; Brunengraber, Henri; Stanley, William C

    2006-01-01

    In the normal heart, there is loss of citric acid cycle (CAC) intermediates that is matched by the entry of intermediates from outside the cycle, a process termed anaplerosis. Previous in vitro studies suggest that supplementation with anaplerotic substrates improves cardiac function during myocardial ischemia and/or reperfusion. The present investigation assessed whether treatment with the anaplerotic medium-chain fatty acid heptanoate improves contractile function during ischemia and reperfusion. The left anterior descending coronary artery of anesthetized pigs was subjected to 60 min of 60% flow reduction and 30 min of reperfusion. Three treatment groups were studied: saline control, heptanoate (0.4 mM), or hexanoate as a negative control (0.4 mM). Treatment was initiated after 30 min of ischemia and continued through reperfusion. Myocardial CAC intermediate content was not affected by ischemia-reperfusion; however, treatment with heptanoate resulted in a more than twofold increase in fumarate and malate, with no change in citrate and succinate, while treatment with hexanoate did not increase fumarate or malate but increased succinate by 1.8-fold. There were no differences among groups in lactate exchange, glucose oxidation, oxygen consumption, and contractile power. In conclusion, despite a significant increase in the content of carbon-4 CAC intermediates, treatment with heptanoate did not result in improved mechanical function of the heart in this model of reversible ischemia-reperfusion. This suggests that reduced anaplerosis and CAC dysfunction do not play a major role in contractile and metabolic derangements observed with a 60% decrease in coronary flow followed by reperfusion.

  4. Citric acid reduces the decline in P300 amplitude induced by acute alcohol consumption in healthy adults

    Institute of Scientific and Technical Information of China (English)

    Wei-xing CHEN; Chuan-qin XU; Shao-hua CHEN; Gen-yun XU; Huai-zhuang YE

    2012-01-01

    Event-related potential (ERP) is a reliable neuroelectric measure of brain activity that helps to confirm the assessment of mental status and cognitive impairment.Many studies have reported that alcoholics show a significantly lower ERP P300 amplitude than the norm.In the present study,ERP P300 waves were measured to evaluate the effect of citric acid on cognitive function during excessive alcohol consumption in healthy adults.Five volunteers were selected through clinical interview,physical examination,and psychiatric assessment for participation in this study.In a double-blind placebo-controlled before-after design,each subject was treated with 5 ml/kg body weight alcohol,5 ml/kg body weight alcohol and 1 mg citric acid,or a placebo on three separate occasions,one week apart.ERP P300,blood biochemical indicators,blood alcohol concentrations (BACs) and acetaldehyde concentrations were assessed.Repeated measure analysis of variance (ANOVA) with a within-subjects factor was used to evaluate differences in blood biochemical indicators,BACs,blood acetaldehyde concentrations,and ERP P300 in the three sessions of assessments.Several blood biochemical indicators showed significant differences between treatments,including the levels of cholinesterase (CHE),total bile acid (TBA),triglyceride (TG),total cholesterol (TC),high-density lipoprotein cholesterol (HDL-C),low-density lipoprotein cholesterol (LDL-C),very low-density lipoprotein cholesterol (VLDL-C),and glycylproline dipeptidyl aminopeptidase (GPDA).BACs after consumption of alcohol alone or citric acid with alcohol were significantly higher compared to those after placebo treatment (P<0.05).There were no significant differences in blood acetaldehyde concentrations between the treatments.The P300 amplitudes on the frontal (Fz),central (Cz),and parietal (Pz) regions of the scalp after consumption of alcohol were significantly lower than those after consumption of the placebo or citric acid with alcohol (P<0

  5. 柠檬酸清洁生产工艺的研究%Study on Cleaner Production Process for Citric Acid

    Institute of Scientific and Technical Information of China (English)

    潘碌亭; 肖锦

    2001-01-01

    The various pollution problems of the traditional production process for citric acid are analyzed and various ways for applying cleaner production process in production of citric acid are proposed.%分析了传统柠檬酸生产工艺存在的污染问题,提出了在柠檬酸生产过程中采用清洁生产技术的各种途径.

  6. Citric acid induces cell-cycle arrest and apoptosis of human immortalized keratinocyte cell line (HaCaT) via caspase- and mitochondrial-dependent signaling pathways.

    Science.gov (United States)

    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.

  7. New fermentation processes for producing itaconic acid and citric acid for industrial uses

    Science.gov (United States)

    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...

  8. Bioavailability of cobalt and iron from citric-acid-adsorbed CoFe2O4 nanoparticles in the terrestrial isopod Porcellio scaber.

    Science.gov (United States)

    Romih, Tea; Drašler, Barbara; Jemec, Anita; Drobne, Damjana; Novak, Sara; Golobič, Miha; Makovec, Darko; Susič, Robert; Kogej, Ksenija

    2015-03-01

    The aim of this study was to determine whether citric acid adsorbed onto cobalt ferrite (CoFe2O4) nanoparticles (NPs) influences the bioavailability of their constituents Co and Fe. Dissolution of Co and Fe was assessed by two measures: (i) in aqueous suspension using chemical analysis, prior to application onto the food of test organisms; and (ii) in vivo, measuring the bioavailability in the model terrestrial invertebrate (Porcellio scaber, Isopoda, Crustacea). The isopods were exposed to citric-acid-adsorbed CoFe2O4 NPs for 2 weeks, and tissue accumulation of Co and Fe was assessed. This was compared to pristine CoFe2O4 NPs, and CoCl2 and Fe(III) salts as positive controls. The combined data shows that citric acid enhances free metal ion concentration from CoFe2O4 NPs in aqueous suspension, although in vivo, very similar amounts of assimilated Co were found in isopods exposed to both types of NPs. Therefore, evaluation of the dissolution in suspension by chemical means is not a good predictor of metal assimilation of this model organism; body assimilation of Co and Fe is rather governed by the physiological capacity of P. scaber for the uptake of these metals. Moreover, we propose that citric acid, due to its chelating properties, may hinder the uptake of Co that dissolves from citric-acid-adsorbed CoFe2O4 NPs, if citric acid is present in sufficient quantity.

  9. Effect of Wheat Middlings, Microbial Phytase, and Citric Acid on Phytate-Phosphorus, Calcium, and Protein Utilization of Broilers

    Institute of Scientific and Technical Information of China (English)

    GONG Yi-feng; LIAO He-rong; WANG Jin-fu; LI Hong-yan

    2006-01-01

    A corn-soybean meal diet (CSB) (or Diet 1) containing 23% crude protein (CP) was used as the positive control, and another corn-soybean meal diet containing 21% CP and 15% wheat middlings (WM) (or Diet 2) was used as the basal diet, which was treated with four different treatments. Digestibility experiment was employed to discuss the collective effect of citric acid, and intrinsic and microbial phytase. By comparing and analyzing effects of them in the low-nutrient broiler diets, the results showed five treatments had similar effects on Tibia ash (%) (mg) (P > 0.05). Under the supplementation of bacterial phytase or citric acid, the daily body weight gain (ADG), gain:feed (G:F) ratio, and calcium (Ca) utilization were similar to that of standard-nutrient CSB diet (Diet 1) (P > 0.05). And, fecal phosphorus (P) and CP utilization were lower than (P < 0.05) that of Diet 1. But P utilization was significantly higher than (P < 0.01) that of Diet 1.However, the ADG, G:F, and CP utilization produced by supplementation of intrinsic phytase were lower than those of Diet 1, but other aspects were similar to those produced by Diet 1 (P > 0.05). In Diet 5, citric acid, intrinsic and bacterial phytase were added to the diet, which produced a 1.4% decrease on fecal P, a 7.2% increase on Ca utilization, which was significantly higher than (P < 0.01) those of the other four Diets, a 3.9% increase on G:F, which was similar to that of Diet 1, and a 2.3% increase on CP utilization, which was higher than (P < 0.05) that of the other three diets. In summary, the results of this study indicated that citric acid, intrinsic and bacterial phytase might have some additive or synergistic effects, and low-nutrient CSB diets with 15% wheat middlings, 750 U kg-1 phytase, and 3% citric acid might substitute completely for standard CSB in broilers.

  10. Retrievability of calcium hydroxide intracanal medicament with three calcium chelators, ethylenediaminetetraacetic acid, citric acid, and chitosan from root canals: An in vitro cone beam computed tomography volumetric analysis

    Science.gov (United States)

    Raghu, Ramya; Pradeep, Geethu; Shetty, Ashish; Gautham, P. M.; Puneetha, P. G.; Reddy, T. V. Satyanarayana

    2017-01-01

    Aim: This study compared the amount of aqueous-based and oil-based calcium hydroxide remaining in the canal, after removal with two different chelators 17% EDTA, 20% Citric acid and 0.2% Chitosan in combination with ultrasonic agitation. Methods and Material: Cleaning and shaping of root canals of 28 mandibular premolar was done and canals were filled either with Metapex or Ca(OH)2 mixed with distilled water. Volumetric analysis was performed utilizing cone beam-computed tomography (CBCT) after seven days of incubation. Ca(OH)2 was removed using either 17% EDTA, 20% Citric acid or 0.2% Chitosan in combination with ultrasonic agitation. Statistical analysis used: Volumetric analysis was repeated and percentage difference was calculated and statistically analyzed using Kruskal-Wallis and Mann-Whitney U test. Results: All the three chelators failed to remove aqueous-based as well as oil-based Ca(OH)2 completely from the root canal. Aqueous-based Ca(OH)2 was easier to be removed than oil-based Ca(OH)2. 0.2% Chitosan in combination with ultrasonics performed better than 17% EDTA and 20% citric acid in removal of Ca(OH)2. Conclusion: Combination of 0.2% Chitosan and ultrasonic agitation results in lower amount of Ca(OH)2 remnants than 17% EDTA, 20% Citric acid irrespective of type of vehicle present in the mix. PMID:28761249

  11. Effect of citric acid and microbial phytase on small intestinal morphology in broiler chicken

    Directory of Open Access Journals (Sweden)

    Rouhollah Nourmohammadi

    2013-01-01

    Full Text Available An experiment was carried out to investigate the effects of citric acid (CA (0, 3 and 6% and microbial phytase (MP (0, 500 and 1000 IU/kg on morphology of different segments of small intestine (duodenum, jejunum and ileum in broiler chickens fed on corn and soybean meal based diets. The effect of 9 experimental treatments (3×3 factorial design were assessed using 270 7-d-old Ross 308 male broiler chicks in a randomized complete block design in three replicates of 10 birds each. The mean villi length (VL, crypt depth (CD and goblet cell number (GCN in duodenum, jejunum and ileum and villi width (VW and VL:CD ratio in duodenum was significantly greater for the birds fed on acidified diets compared to the control birds at day 42 of age (P<0.01. Inclusion of 3% CA in diet significantly decreased the epithelial thickness (ET in duodenum, jejunum and ileum (P<0.01. The birds received diets with 1000 IU/kg of MP showed significant increase in CD (P<0.01 and GCN in jejunum (P<0.05, and significant decrease in VL:CD ratio and ET in the duodenum (P<0.01, jejunum (P<0.05 and ileum (P<0.01 segments. No variable of interest were affected by CA × MP interaction. It was concluded that CA and MP independently exhibit positive impact on morphometery of small intestine, toward facilitating the nutrient absorption and reducing the metabolic demands of the intestinal tract in broiler chickens.

  12. Citric acid production from orange peel wastes by solid-state fermentation

    Directory of Open Access Journals (Sweden)

    Ana María Torrado

    2011-03-01

    Full Text Available 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 0.7·10(8 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 0.5·10(6 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.

  13. Development and characterization of antibacterial braided polyamide suture coated with chitosan-citric acid biopolymer.

    Science.gov (United States)

    Debbabi, Faten; Gargoubi, Sondes; Hadj Ayed, Mohamed Adnene; Abdessalem, Saber Ben

    2017-09-01

    Braided polyamide sutures are frequently used in dermatologic surgery for wound closure. However, braided sutures promote bacteria proliferation. In order to prevent wound complications due to this effect, antibacterial sutures should be used. The main objective of this study is the development of new non-absorbable antibacterial polyamide braided suture. This paper suggests new coating process that leads to obtain suture uniformly covered by antibacterial film enclosing chitosan, which is known for its antibacterial benefit. Mechanical properties and surface morphology of developed sutures were investigated by using mechanical tests. Sutures surfaces were also examined by scanning electron microscope, to perceive spreading of coating product on suture surface. In order to identify potential reactions between chemical compounds present in coating solution and suture material, sutures were analyzed by ATR-IF spectroscopy. It has been demonstrated that many eventual bonds between compounds present in coating solutions and polyamide macromolecular chain may occur. The existence of these bonds implies the fixation of biopolymer coating on suture surface. It has been demonstrated that uniform surface may be obtained by progressively applying coating solution containing little amount of chitosan on suture surface. We have also found that developed coating process has not affected mechanical properties of suture, which still meet United States Pharmacopeia requirement. Finally, antibacterial effects against four colonies, very widespread in hospitals, were studied. Prominent antibacterial effects of braided polyamide suture against two gram-positive ( S Aureus, S epidermidis) and two gram-negative ( E coli and P aeruginosa) colonies are presented. Optimal result of best properties is obtained by applying three layers of biopolymer coating comprising 1% chitosan and 10% citric acid. The new developed suture coating process appears as a promising method for obtaining

  14. Pyruvate and citric acid cycle carbon requirements in isolated skeletal muscle mitochondria.

    Science.gov (United States)

    Messer, Jeffrey I; Jackman, Matthew R; Willis, Wayne T

    2004-03-01

    Carbohydrate depletion precipitates fatigue in skeletal muscle, but, because pyruvate provides both acetyl-CoA for mainline oxidation and anaplerotic carbon to the citric acid cycle (CAC), the mechanism remains obscure. Thus pyruvate and CAC kinetic parameters were independently quantified in mitochondria isolated from rat mixed skeletal muscle. Mitochondrial oxygen consumption rate (Jo) was measured polarographically while either pyruvate or malate was added stepwise in the presence of a saturating concentration of the other substrate. These substrate titrations were carried out across a physiological range of fixed extramitochondrial ATP free energy states (DeltaGP), established with a creatine kinase energy clamp, and also at saturating [ADP]. The apparent Km,malate for mitochondrial Jo ranged from 21 to 32 microM, and the apparent Km,pyruvate ranged from 12 to 26 microM, with both substrate Km values increasing as DeltaGP declined. Vmax for both substrates also increased as DeltaGP fell, reflecting thermodynamic control of Jo. Reported in vivo skeletal muscle [malate] are >10-fold greater than the Km,malate determined in this study. In marked contrast, the K(m,pyruvate) determined is near the [pyruvate] reported in muscle approaching exhaustion associated with glycogen depletion. When data were evaluated in the context of a linear thermodynamic force-flow (DeltaGP-Jo) relationship, the DeltaGP-Jo slope was essentially insensitive to changes in [malate] in the range observed in vivo but decreased markedly with declining [pyruvate] across the physiological range. Mitochondrial respiration is particularly sensitive to variations in [pyruvate] in the physiological range. In contrast, physiological [malate] exerts very little, if any, influence on mitochondrial pyruvate oxidation measured in vitro.

  15. Organising pneumonia associated with fumaric acid ester treatment for psoriasis.

    LENUS (Irish Health Repository)

    Deegan, Alexander Paul

    2012-02-01

    INTRODUCTION: We present the case of a 49-year old male who presented with dyspnoea, cough, weight loss, night sweats and general malaise. He had been on treatment with oral fumaric acid esters (FAE, Fumaderm(R); Biogen Idec GmbH, Ismaning, Germany) for 6 months. METHODS: Report of a case. RESULTS: His chest X-ray showed patchy infiltrates in the left upper lobe which failed to resolve under empiric antibiotic therapy. A computed tomography of thorax revealed bilateral, mostly peripheral foci of consolidation with air bronchograms. Transbronchial biopsies showed a pattern of organising pneumonia (OP). CONCLUSIONS: Therapy with oral prednisolone (40 mg\\/day) resulted in a rapid clinical and radiological improvement. An association of FAE and OP has not previously been reported. Please cite this paper as: Deegan AP, Kirby B, Rogers S, Crotty TB and McDonnell TJ. Organising pneumonia associated with fumaric acid ester treatment for psoriasis.

  16. Enzymatic synthesis and application of fatty acid ascorbyl esters

    Directory of Open Access Journals (Sweden)

    Stojanović Marija M.

    2013-01-01

    Full Text Available Fatty acid ascorbyl esters are liposoluble substances that possess good antioxidative properties. These compounds could be synthesized by using various acyl donors for acylation of vitamin C in reaction catalyzed by chemical means or lipases. Enzymatic process is preferred since it is regioselective, performed under mild reaction conditions, with the obtained product being environmentally friendly. Polar organic solvents, ionic liquids, and supercritical fluids has been successfully used as a reaction medium, since commonly used solvents with high Log P values are inapplicable due to ascorbic acid high polarity. Acylation of vitamin C using fatty acids, their methyl-, ethyl-, and vinyl esters, as well as triglycerides has been performed, whereas application of the activated acyl donors enabled higher molar conversions. In each case, majority of authors reported that using excessive amount of the acyl donor had positive effect on yield of product. Furthermore, several strategies have been employed for shifting the equilibrium towards the product by water content control. These include adjusting the initial water activity by pre-equilibration of reaction mixture, enzyme preparation with water vapor of saturated salt solutions, and the removal of formed water by the addition of molecular sieves or salt hydrate pairs. The aim of this article is to provide a brief overview of the procedures described so far for the lipase-catalyzed synthesis of fatty acid ascorbyl esters with emphasis on the potential application in food, cosmetics, and pharmaceutics. Furthermore, it has been pointed out that the main obstacles for process commercialization are long reaction times, lack of adequate purification methods, and high costs of lipases. Thus, future challenges in this area are testing new catalysts, developing continuous processes for esters production, finding cheaper acyl donors and reaction mediums, as well as identifying standard procedures for

  17. Evaluation of salicylic acid fatty ester prodrugs for UV protection.

    Science.gov (United States)

    Im, Jong Seob; Balakrishnan, Prabagar; Oh, Dong Hoon; Kim, Jung Sun; Jeon, Eun-Mi; Kim, Dae-Duk; Yong, Chul Soon; Choi, Han-Gon

    2011-07-01

    The purpose of this study was to investigate the physicochemical properties and in vitro evaluation of fatty ester prodrugs of salicylic acid for ultraviolet (UV) protection. The physicochemical properties such as lipophilicity, chemical stability and enzymatic hydrolysis were investigated with the following fatty ester prodrugs of salicylic acid: octanoyl (C8SA), nonanoyl (C9SA), decanoyl (C10SA), lauroyl (C12SA), myristoyl (C14SA) and palmitoyl oxysalicylate (C16SA). Furthermore, their skin permeation and accumulation were evaluated using a combination of common permeation enhancing techniques such as the use of a lipophilic receptor solution, removal of stratum corneum and delipidization of skin. Their k' values were proportional to the degree of carbon-carbon saturation in the side chain. All these fatty esters were highly stable in 2-propanol, acetonitrile and glycerin, but unstable in methanol and ethanol. They were relatively unstable in liver and skin homogenates. In particular, C16SA was mostly hydrolyzed to its parent compound in hairless mouse liver and skin homogenates, suggesting that it might be converted to salicylic acid after its topical administration. In the skin permeation and accumulation study, C16SA showed the poorest permeation in all skins, suggesting that it could not be permeated in the skin. Furthermore, C14SA and C16SA were less accumulated in delipidized skin compared with normal skin or stripped skin, suggesting that these esters had relatively strong affinities for lipids compared with the other prodrugs in the skin. C16SA showed significantly higher dermal accumulation in all skins compared with its parent salicylic acid. Thus, the palmitoyl oxysalicylate (C16SA) might be a potential candidate for UV protection due to its absence of skin permeation, smaller uptake in the lipid phase and relatively lower skin accumulation.

  18. The Zinc Mediated Condensation of Amino Acid Esters with Imines to b-Lactams

    NARCIS (Netherlands)

    Koten, G. van; Jastrzebski, J.T.B.H.

    1993-01-01

    An experimentally attractive stereoselectie 'one pot' synthesis of beta-lactams is described. This route is based on the zinc mediated condensation of an alpha-amino acid ester with an imine via a zinc ester enolate. Making use of proper substituents in both the amino acid ester and the imine the st

  19. 40 CFR 721.10133 - 2-Propenoic acid, 2-methyl, 2-hydroxyethyl ester, homopolymer.

    Science.gov (United States)

    2010-07-01

    ...-hydroxyethyl ester, homopolymer. 721.10133 Section 721.10133 Protection of Environment ENVIRONMENTAL PROTECTION... New Uses for Specific Chemical Substances § 721.10133 2-Propenoic acid, 2-methyl, 2-hydroxyethyl ester... identified as 2-propenoic acid, 2-methyl, 2-hydroxyethyl ester, homopolymer (PMN P-07-401; CAS No....

  20. 40 CFR 721.10165 - Carbonotrithioic acid, bis(phenylmethyl) ester.

    Science.gov (United States)

    2010-07-01

    ...(phenylmethyl) ester. 721.10165 Section 721.10165 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.10165 Carbonotrithioic acid, bis(phenylmethyl) ester. (a) Chemical... carbonotrithioic acid, bis(phenylmethyl) ester (PMN P-08-138; CAS No.26504-29-0) is subject to reporting under...

  1. 40 CFR 721.2078 - 1-Piperidinecarboxylic acid, 2-[(dichloro-hydroxy-carbomonocycle)hydrazono]-, methyl ester...

    Science.gov (United States)

    2010-07-01

    ...- -, methyl ester (generic). 721.2078 Section 721.2078 Protection of Environment ENVIRONMENTAL PROTECTION... New Uses for Specific Chemical Substances § 721.2078 1-Piperidinecarboxylic acid, 2- -, methyl ester... generically identified as 1-piperidinecarboxylic acid, 2- -, methyl ester (PMN P-96-756) is subject...

  2. 40 CFR 721.7770 - Alkylphenoxypoly(oxyethylene) sulfuric acid ester, substituted amine salt.

    Science.gov (United States)

    2010-07-01

    ... acid ester, substituted amine salt. 721.7770 Section 721.7770 Protection of Environment ENVIRONMENTAL... ester, substituted amine salt. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as alkyl phenoxypoly(oxyethylene) sulfuric acid ester,...

  3. 40 CFR 721.1577 - 1,4-Benzenedicarboxylic acid, bis [4-(ethenyloxy) butyl] ester.

    Science.gov (United States)

    2010-07-01

    ... ester. 721.1577 Section 721.1577 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Specific Chemical Substances § 721.1577 1,4-Benzenedicarboxylic acid, bis ester. (a) Chemical substance and... acid, bis ester (PMN P-98-1163; CAS No. 117397-31-6) is subject to reporting under this section for...

  4. 78 FR 46283 - Modification of Significant New Uses of Ethaneperoxoic Acid, 1,1-Dimethylpropyl Ester

    Science.gov (United States)

    2013-07-31

    ...- Dimethylpropyl Ester AGENCY: Environmental Protection Agency (EPA). ACTION: Final rule. SUMMARY: Under the Toxic... chemical substance identified as ethaneperoxoic acid, 1,1- dimethylpropyl ester, which was the subject of... substance identified as ethaneperoxoic acid, 1,1-dimethylpropyl ester, (PMN P-85-680). Potentially...

  5. 40 CFR 721.987 - Dialkylaminophenyl imino pyrazole acid ester (generic).

    Science.gov (United States)

    2010-07-01

    ... ester (generic). 721.987 Section 721.987 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.987 Dialkylaminophenyl imino pyrazole acid ester (generic). (a) Chemical... as dialkylaminophenyl imino pyrazole acid ester (PMN P-98-45) is subject to reporting under...

  6. 40 CFR 721.1579 - 1,2,4-Benzenetricarboxylic acid, tris [4-(ethenyloxy) butyl] ester.

    Science.gov (United States)

    2010-07-01

    ... ester. 721.1579 Section 721.1579 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Specific Chemical Substances § 721.1579 1,2,4-Benzenetricarboxylic acid, tris ester. (a) Chemical substance...-benzenetricarboxylic acid, tris ester (PMN P-98-1165; CAS No. 196109-17-8) is subject to reporting under this...

  7. 40 CFR 721.3680 - Ethylene oxide adduct of fatty acid ester with pentaerythritol.

    Science.gov (United States)

    2010-07-01

    ... ester with pentaerythritol. 721.3680 Section 721.3680 Protection of Environment ENVIRONMENTAL PROTECTION... New Uses for Specific Chemical Substances § 721.3680 Ethylene oxide adduct of fatty acid ester with... identified generically as ethylene oxide adduct of fatty acid ester with pentaerythritol (PMN P-91-442)...

  8. 40 CFR 721.8160 - Propanoic acid, 2,2-dimethyl-, ethenyl ester.

    Science.gov (United States)

    2010-07-01

    ... ester. 721.8160 Section 721.8160 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Specific Chemical Substances § 721.8160 Propanoic acid, 2,2-dimethyl-, ethenyl ester. (a) Chemical... acid, 2,2-dimethyl-, ethenyl ester (PMN P-89-1058) is subject to reporting under this section for...

  9. 40 CFR 721.7290 - Propanoic acid, 2-(trimethoxysilyl)-, ethyl ester.

    Science.gov (United States)

    2010-07-01

    ...)-, ethyl ester. 721.7290 Section 721.7290 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.7290 Propanoic acid, 2-(trimethoxysilyl)-, ethyl ester. (a) Chemical... acid, 2-(trimethoxysilyl)-, ethyl ester (PMN P-01-22; CAS No. 137787-41-8) is subject to...

  10. 21 CFR 178.3450 - Esters of stearic and palmitic acids.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Esters of stearic and palmitic acids. 178.3450 Section 178.3450 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... SANITIZERS Certain Adjuvants and Production Aids § 178.3450 Esters of stearic and palmitic acids. The ester...

  11. 40 CFR 721.9965 - Fatty acids, C10-13 - branched, vinyl esters.

    Science.gov (United States)

    2010-07-01

    ... esters. 721.9965 Section 721.9965 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Specific Chemical Substances § 721.9965 Fatty acids, C10-13 - branched, vinyl esters. (a) Chemical... acids, C10-13 - branched, vinyl esters (PMN P-97-482; CAS No. 184785-38-4) is subject to reporting under...

  12. 21 CFR 178.3780 - Polyhydric alcohol esters of long chain monobasic acids.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Polyhydric alcohol esters of long chain monobasic..., PRODUCTION AIDS, AND SANITIZERS Certain Adjuvants and Production Aids § 178.3780 Polyhydric alcohol esters of long chain monobasic acids. Polyhydric alcohol esters of long chain monobasic acids identified in...

  13. Citric acid as the last therapeutic approach in an acute life-threatening metabolic decompensation of propionic acidaemia.

    Science.gov (United States)

    Siekmeyer, Manuela; Petzold-Quinque, Stefanie; Terpe, Friederike; Beblo, Skadi; Gebhardt, Rolf; Schlensog-Schuster, Franziska; Kiess, Wieland; Siekmeyer, Werner

    2013-01-01

    The tricarboxylic acid (TCA) cycle represents the key enzymatic steps in cellular energy metabolism. Once the TCA cycle is impaired in case of inherited metabolic disorders, life-threatening episodes of metabolic decompensation and severe organ failure can arise. We present the case of a 6 ½-year-old girl with propionic acidaemia during an episode of acute life-threatening metabolic decompensation and severe lactic acidosis. Citric acid given as an oral formulation showed the potential to sustain the TCA cycle flux. This therapeutic approach may become a treatment option in a situation of acute metabolic crisis, possibly preventing severe disturbance of energy metabolism.

  14. Fatty acid methyl esters yield and phorbol esters degradation during transesterification of Jatropha curcas oil by alkaline, acid and enzyme catalyzed method

    Directory of Open Access Journals (Sweden)

    Tosa Koji

    2017-01-01

    Full Text Available Jatropha curcas has recently been the focus of intense research as a raw material of biomass fuel. However, the carcinogenesis promoter action of the phorbol esters in the Jatropha raises concerns for health and environmental risk. The purpose of the present study is to determine the relationship between the fatty acid methyl esters yield and the phorbol esters degradation ratio during the transesterification of the Jatropha oil by alkaline, acid and enzyme catalyzed method, respectively. The phorbol esters in Jatropha oil were degraded during the transesterification of the Jatropha curcas oil by alkaline and acid catalyzed methanol methods. The degradation ratio was significantly correlated with the fatty acid methyl esters yields in alkaline catalyzed transesterification. The results obtained in this study suggest that the health and environmental risk of the phorbol esters in a Jatropha BDF can be significantly reduced by a complete transesterification of the crude oil by controlling the transesterification condition appropriately.

  15. Influence of passion fruit albedo, citric acid, and the pulp/sugar ratio on the quality of banana preserves

    Directory of Open Access Journals (Sweden)

    Igor Galvão Silva

    2012-06-01

    Full Text Available The objective of this research was to evaluate the effect of the citric acid concentration, pulp/sugar ratio, and albedo concentration of the passion fruit peel on physical, physiochemical, and sensorial characteristics of the 'Silver' banana preserves. A 2³ factorial design and 3 repetitions in the central point were used. The albedo concentration between 0 and 3% had significant influence on the reduction of the reducing sugars and on the decrease in titratable acidity. The increase in the pulp/sugar ratio exerted a negative effect on the pH and positive on the titratable acidity; the acid addition reduced the non-reducing sugar level. The sensorial evaluation and purchase intention indicated that the incorporation of a maximum of 1.5% albedo in formulations containing 50% pulp and 0.5% citric acid resulted in products with good acceptability in comparison with the formulation in which 60% pulp and an absence of acid or albedo is utilized.

  16. Fatty acid methyl ester profiles of bat wing surface lipids.

    Science.gov (United States)

    Pannkuk, Evan L; Fuller, Nathan W; Moore, Patrick R; Gilmore, David F; Savary, Brett J; Risch, Thomas S

    2014-11-01

    Sebocytes are specialized epithelial cells that rupture to secrete sebaceous lipids (sebum) across the mammalian integument. Sebum protects the integument from UV radiation, and maintains host microbial communities among other functions. Native glandular sebum is composed primarily of triacylglycerides (TAG) and wax esters (WE). Upon secretion (mature sebum), these lipids combine with minor cellular membrane components comprising total surface lipids. TAG and WE are further cleaved to smaller molecules through oxidation or host enzymatic digestion, resulting in a complex mixture of glycerolipids (e.g., TAG), sterols, unesterified fatty acids (FFA), WE, cholesteryl esters, and squalene comprising surface lipid. We are interested if fatty acid methyl ester (FAME) profiling of bat surface lipid could predict species specificity to the cutaneous fungal disease, white nose syndrome (WNS). We collected sebaceous secretions from 13 bat spp. using Sebutape(®) and converted them to FAME with an acid catalyzed transesterification. We found that Sebutape(®) adhesive patches removed ~6× more total lipid than Sebutape(®) indicator strips. Juvenile eastern red bats (Lasiurus borealis) had significantly higher 18:1 than adults, but 14:0, 16:1, and 20:0 were higher in adults. FAME profiles among several bat species were similar. We concluded that bat surface lipid FAME profiling does not provide a robust model predicting species susceptibility to WNS. However, these results provide baseline data that can be used for lipid roles in future ecological studies, such as life history, diet, or migration.

  17. 21 CFR 172.225 - Methyl and ethyl esters of fatty acids produced from edible fats and oils.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Methyl and ethyl esters of fatty acids produced... Methyl and ethyl esters of fatty acids produced from edible fats and oils. Methyl esters and ethyl esters... following prescribed conditions: (a) The additive consists of a mixture of either methyl or ethyl esters of...

  18. Effect of citric acid and bacteria on metal uptake in reeds grown in a synthetic acid mine drainage solution.

    Science.gov (United States)

    Guo, Lin; Cutright, Teresa J

    2015-03-01

    The effect of citric acid (CA), rhizosphere acidophilic heterotrophs and/or Fe(II) oxidizing bacteria (Fe(II)OB) on plaque formation and metal accumulation in Phragmites australis L. (common reed) from acid mine drainage (AMD) solution were investigated. Reeds were grown in different hydroponic solutions that contained AMD, CA and/or rhizosphere bacteria for three months. Triplicate experiments were conducted for each experimental condition. Fe(II)OB enhanced the formation of Fe plaque which decreased Fe and Mn uptake in reeds, while it had no significant influence on Al accumulation. CA inhibited the growth of Fe(II)OB, decreased the formation of metal plaque and increased Fe and Mn accumulation in reeds. Acidophilic heterotrophs consumed CA and made the environment more suitable for the growth of Fe(II)OB. Reeds are a good candidate for phytoextraction while CA is a useful chelator to enhance metal uptake in plants. More research may be needed to investigate the influence of CA on microbial community. Further investigations are required to study the effect of CA on phytoremediation of AMD contaminated fields. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Browning inhibition mechanisms by cysteine, ascorbic acid and citric acid, and identifying PPO-catechol-cysteine reaction products.

    Science.gov (United States)

    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.

  20. Citric acid and ethylene diamine tetra-acetic acid as effective washing agents to treat sewage sludge for agricultural reuse.

    Science.gov (United States)

    Ren, Xianghao; Yan, Rui; Wang, Hong-Cheng; Kou, Ying-Ying; Chae, Kyu-Jung; Kim, In S; Park, Yong-Jin; Wang, Ai-Jie

    2015-12-01

    This paper presents the effects of different concentrations of citric acid (CA) and ethylene diamine tetra-acetic acid (EDTA) when used as additive reagents for the treatment of sewage sludge for agricultural use. Herein, both the retention of nutrients and removal of metals from the sewage sludge are examined. The average removal rate for the metals after treatment by CA decreased in the order Cu>Pb>Cd>Cr>Zn, while the rates after treatment by EDTA decreased in the order of Pb>Cu>Cr>Cd>Zn. After treatment with CA and EDTA, total nitrogen and total phosphorus concentrations in the sludge decreased, while the content of available nitrogen and Olsen-P increased. In addition, a multi-criteria analysis model-fuzzy analytic network process method (with 3 main factors and 12 assessment sub-factors) was adopted to evaluate the effectiveness of different treatment methods. The results showed that the optimal CA and EDTA concentrations for sewage sludge treatment were 0.60 and 0.125 mol/L, respectively.

  1. The role of citric acid and ascorbic acid in morphology control of palladium nanocrystals: A molecular dynamics and density functional theory study

    Science.gov (United States)

    Yue, Jeffrey; Du, Zheng; Shao, Minhua

    2016-08-01

    The effect of surfactants on the synthesis of shape-controlled palladium (Pd) nanocrystals was studied using computational simulation methods. We found that the functional groups in surfactant molecules played an important role in the specific adsorption on Pd surfaces. Citric acid and ascorbic acid were found to be preferentially adsorbed onto Pd(1 1 1) and (1 0 0) planes resulting in the formation of octahedral and cubic nanocrystals, respectively.

  2. Cu(I)-catalyzed (11)C carboxylation of boronic acid esters: a rapid and convenient entry to (11)C-labeled carboxylic acids, esters, and amides.

    Science.gov (United States)

    Riss, Patrick J; Lu, Shuiyu; Telu, Sanjay; Aigbirhio, Franklin I; Pike, Victor W

    2012-03-12

    Rapid and direct: the carboxylation of boronic acid esters with (11)CO(2) provides [(11)C]carboxylic acids as a convenient entry into [(11)C]esters and [(11)C]amides. This conversion of boronates is tolerant to diverse functional groups (e.g., halo, nitro, or carbonyl).

  3. Exploring unsaturated fatty acid cholesteryl esters as transdermal permeation enhancers.

    Science.gov (United States)

    Rambharose, Sanjeev; Kalhapure, Rahul S; Jadhav, Mahantesh; Govender, Thirumala

    2017-04-01

    The intrinsic protective barrier property of skin, one of the major challenges in the design of transdermal drug delivery systems, can be overcome through the use of chemical permeation enhancers (CPEs). Herein, we explore the potential of unsaturated fatty acid (UFA) esters of cholesterol (Chol) viz., oleate, linoleate and linolenate, as transdermal CPEs using tenofovir (TNF) as a model drug. All Chol UFA esters at 1% w/w were found to be more effective enhancers when compared to their respective parent fatty acids (FAs) and saturated FA counterparts. Cholesteryl linolenate (Chol-LLA) showed the most superior performance (enhancement ratio (ER) = 3.71). The greatest ER for Chol-LLA (5.93) was achieved at a concentration of 2% w/w. The histomorphological and transepithelial electrical resistance (TEER) evaluations supported the results of the permeability studies. These findings showed no significant loss in the integrity of the epidermis, with drug and enhancer treatment having temporary effects on the barrier property of the epidermis. Chol UFA esters can therefore be considered as new CPEs for exploitation in topical formulations for various classes of drugs.

  4. Metabolism: Part II. The Tricarboxylic Acid (TCA), Citric Acid, or Krebs Cycle.

    Science.gov (United States)

    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)

  5. Metabolism: Part II. The Tricarboxylic Acid (TCA), Citric Acid, or Krebs Cycle.

    Science.gov (United States)

    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)

  6. Application of lipase technology for transesterification of fatty acid ester

    Directory of Open Access Journals (Sweden)

    JOKO SULISTYO

    2005-07-01

    Full Text Available We have reported the potency of microbial extracellular enzyme for synthesis of fatty acid ester. Further investigation was aimed to study capacity of the enzyme on bioprocess of crude palm oil by transesterification of saturated fatty acid to fatty acid ester. We have studied some lipases from culture filtrate of Candida rugosa FM-9301, Bacillus subtilis FM-9101 and Pseudomonas aerogenes FM-9201, which were preincubated in a medium containing olive oil as inducers, using a shaker under conditions that allowed for lipase production at pH 4.5-6.5 and room temperature for 5 days. Those strains shown different activities during the hydrolysis of substrates, which resulted in decreasing or increasing free fatty acids those, were liberated from media containing crude palm oil and organic solvents. The optimal transesterification condition was at temperature of 45-50C and at pH 4.5 for C. rugosa and pH 6.0 to 7.0 for P. aerogenes and B. subtilis. Under the enzyme concentration of 50% (v/v, the transesterification was rapidly occurred, while at the concentration of 20% (v/v the enzymatically biosynthesis required longer incubation period. The substrates incubated with C. rugosa lipase exhibited higher linoleic and linolenic acid (7.16 and 2.15%, respectively, than that of B. subtilis lipase (4.85% and 1.43%, respectively, while P. aerogenes lipase (3.73% and 1.11%, respectively.

  7. The relationship between fatty acid and citric acid concentrations in milk from Holstein cows during the period of negative energy balance / Vztah mezi obsahem mastnych kyselin a kyseliny citronove v mlece dojnic holstynskeho skotu v prubehu obdobi zaporne energeticke laktace

    National Research Council Canada - National Science Library

    Duchacek, Jaromir; Stadnik, Ludek; Beran, Jan; Okrouhla, Monika

    2012-01-01

    The objective of this study was to determine the relationship between body condition score changes and the dynamics of energy balance indicators - fatty acid and citric acid contents - in milk during...

  8. EFFECT OF NITRITE AND CITRIC ACID ON THE CHEMICAL COMPOSITION AND pH OF THE CANNED BEEF SAUSAGES

    Directory of Open Access Journals (Sweden)

    M.M.A. MAHA

    2015-01-01

    Full Text Available The effects of nitrite and citric acid as preservatives on the chemical composition and pH of the canned beef sausage were investigated after three months storage at room temperature (35±5ºc. Two experiments were conducted in this study, the first, was undertaken to determine the effect of nitrite as a preservative on the chemical composition and pH of the canned beef sausages retorted at 107.2°C (225ºF for 80 minutes, and at 115.5°C (240ºF for 40 minutes. The second experiment, which was based on the results of the first one, was conducted to determine the effects of the absence of nitrite on the canned beef sausage processed with meat treated by immersion in 1% citric acid before processing at (80 and 30ºc for one minute and drained, then the product retorted at 107.2°C for 80 minutes. The evaluation of percentages of the dry matter, ash, crude protein, fat and also pH were done monthly. The results in experiment 1 indicated that, percentages of the dry matter, ash and crude protein before and after canning of sausages were not significantly different (P>0.05. The fat (% was significantly different among treatments (P0.05 for the raw, cooked and canned sausages. Generally it was observed a decrease in moisture content (increases in dry matter content, ash%, crude protein fat (% and pH value with increasing of storage period. Citric acid had no clear effect on chemical properties and pH value.

  9. Linear birefringence and dichroism in citric acid coated Fe{sub 3}O{sub 4} magnetic nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Jing-Fung, E-mail: jacklin@cc.feu.edu.tw [Graduate School of Computer Application Engineering, Far East University, No. 49, Zhonghua Road, Xinshi District, Tainan, Taiwan, ROC (China); Tsai, Chun-Chin [Department of Optoelectronic Engineering, Far East University, No. 49, Zhonghua Road, Xinshi District, Tainan, Taiwan, ROC (China); Lee, Meng-Zhe [Graduate School of Computer Application Engineering, Far East University, No. 49, Zhonghua Road, Xinshi District, Tainan, Taiwan, ROC (China)

    2014-12-15

    To prepare highly dispersed water-based Fe{sub 3}O{sub 4} magnetic nanoparticles (MNPs), we adopted the co-precipitation method and used citric acid (CA) as the surfactant. Via transmission electronic microscopy, dynamic light scattering, and X-ray diffractometry, we characterized the dispersibility and size of the products. Through two single-parameter experiments, including the pH value of suspension and the action of double centrifugations, the appropriate parameters' values were determined. Further, to produce CA coated MNPs with good magneto-optical properties as high retardance and low dichroism, the orthogonal design method was used to find the optimal parameters' values, including pH value of suspension after coating was 5, molar ratio of CA to Fe{sub 3}O{sub 4} MNPs was 0.06, volume of CA was 40 ml, and coating temperature was 70 °C. Above all, the linear birefringence and dichroism of the best CA coated ferrofluid we produced were measured by a Stokes polarimeter as 23.6294° and 0.3411 under 64.5 mT, respectively. Thus, the biomedical applications could be performed hereafter. - Highlights: • We examine pH changes about retardance/dichroism of citric acid coated ferrofluid. • We examine centrifugal action about dispersity of citric acid coated ferrofluid. • Dispersity of coated suspensions with different pH is investigated by DLS results. • Optimum combination and influence sequence obtained by Taguchi method is found. • Molar ratio of CA to Fe{sub 3}O{sub 4} deeply influences the retardance and dichroism of FFs.

  10. Effects of two desensitizing dentifrices on dentinal tubule occlusion with citric acid challenge: Confocal laser scanning microscopy study

    Directory of Open Access Journals (Sweden)

    Sneha Anil Rajguru

    2017-01-01

    Full Text Available Background: Dentin hypersensitivity results when patent tubules are exposed to pain-inducing external stimuli. Aim: This study aims to compare the effects of two desensitizing dentifrices containing NovaMin and arginine on dentinal tubule occlusion with and without citric acid challenge in vitro using confocal laser scanning microscopy (CLSM. Materials and Methods: Forty dentin discs were randomly divided into Groups I and II containing twenty specimens each, treated with NovaMin and arginine-containing dentifrices, respectively. Groups I and II were divided into subgroups A and B where IA and IIA underwent CLSM analysis to determine the percentage of tubule occlusion while IB and IIB underwent 0.3% citric acid challenge and CLSM analysis. A novel grading system was devised to categorize tubule occlusion. Results: In Group II, the percentage of occluded tubules was highest for IIA (72.25% ± 10.57% and least for IIB (42.55% ± 8.65% having statistical significance (P < 0.0005. In Group I, the difference between IA (49.9% ± 12.96% and IB (43.15% ± 12.43% was statistically insignificant (P = 0.249. On the comparison between IB and IIB statistically indifferent result was obtained (P = 0.901, whereas the difference between IA and IIA was statistically significant (P < 0.001. The results of grading system were for IA 50% of samples belonged to Grade 2, for IIA 60% - Grade 3, and for IB 70% and for IIB 90% - Grade 2. Conclusion: Dentinal tubule occlusion with arginine-containing dentifrice was significantly higher than NovaMin. However, it could not resist citric acid challenge as effectively as NovaMin. The effects of NovaMin were more sustainable as compared to arginine-containing dentifrice, thus proving to be a better desensitizing agent.

  11. Preparation and Application of Starch/Polyvinyl Alcohol/Citric Acid Ternary Blend Antimicrobial Functional Food Packaging Films

    Directory of Open Access Journals (Sweden)

    Zhijun Wu

    2017-03-01

    Full Text Available Ternary blend films were prepared with different ratios of starch/polyvinyl alcohol (PVA/citric acid. The films were characterized by field emission scanning electron microscopy (FE-SEM, thermogravimetric analysis, as well as Fourier transform infrared (FTIR analysis. The influence of different ratios of starch/polyvinyl alcohol (PVA/citric acid and different drying times on the performance properties, transparency, tensile strength (TS, water vapor permeability (WVP, water solubility (WS, color difference (ΔE, and antimicrobial activity of the ternary blends films were investigated. The starch/polyvinyl alcohol/citric acid (S/P/C1:1:0, S/P/C3:1:0.08, and S/P/C3:3:0.08 films were all highly transparent. The S/P/C3:3:0.08 had a 54.31 times water-holding capacity of its own weight and its mechanical tensile strength was 46.45 MPa. In addition, its surface had good uniformity and compactness. The S/P/C3:1:0.08 and S/P/C3:3:0.08 showed strong antimicrobial activity to Listeria monocytogenes and Escherichia coli, which were the food-borne pathogenic bacteria used. The freshness test results of fresh figs showed that all of the blends prevented the formation of condensed water on the surface of the film, and the S/P/C3:1:0.08 and S/P/C3:3:0.08 prevented the deterioration of figs during storage. The films can be used as an active food packaging system due to their strong antibacterial effect.

  12. Effects of two desensitizing dentifrices on dentinal tubule occlusion with citric acid challenge: Confocal laser scanning microscopy study.

    Science.gov (United States)

    Rajguru, Sneha Anil; Padhye, Ashvini M; Gupta, Himani S

    2017-01-01

    Dentin hypersensitivity results when patent tubules are exposed to pain-inducing external stimuli. This study aims to compare the effects of two desensitizing dentifrices containing NovaMin and arginine on dentinal tubule occlusion with and without citric acid challenge in vitro using confocal laser scanning microscopy (CLSM). Forty dentin discs were randomly divided into Groups I and II containing twenty specimens each, treated with NovaMin and arginine-containing dentifrices, respectively. Groups I and II were divided into subgroups A and B where IA and IIA underwent CLSM analysis to determine the percentage of tubule occlusion while IB and IIB underwent 0.3% citric acid challenge and CLSM analysis. A novel grading system was devised to categorize tubule occlusion. In Group II, the percentage of occluded tubules was highest for IIA (72.25% ± 10.57%) and least for IIB (42.55% ± 8.65%) having statistical significance (P < 0.0005). In Group I, the difference between IA (49.9% ± 12.96%) and IB (43.15% ± 12.43%) was statistically insignificant (P = 0.249). On the comparison between IB and IIB statistically indifferent result was obtained (P = 0.901), whereas the difference between IA and IIA was statistically significant (P < 0.001). The results of grading system were for IA 50% of samples belonged to Grade 2, for IIA 60% - Grade 3, and for IB 70% and for IIB 90% - Grade 2. Dentinal tubule occlusion with arginine-containing dentifrice was significantly higher than NovaMin. However, it could not resist citric acid challenge as effectively as NovaMin. The effects of NovaMin were more sustainable as compared to arginine-containing dentifrice, thus proving to be a better desensitizing agent.

  13. THE INFLUENCE OF PVA.cl.CITRIC ACID/CHITOSAN MEMBRANE HYDROPHICILITY ON THE TRANSPORT OF CREATININE AND UREA

    Directory of Open Access Journals (Sweden)

    Retno Ariadi Lusiana

    2013-12-01

    Full Text Available The influence of cross-linking and membrane hydrophilicity on the transport rate had been studied using a membrane prepared from a mixture of chitosan/PVA cross-linked citric acid (PVA.cl.CA for creatinine and urea transport. The optimum mole ratio of PVA:citric acid as well as the best composition of chitosan:PVA.cl.CA were determined using creatinine transport study. Using the optimum compositions, further study was done using different thickness of the membrane in transporting creatinine, urea and a mixture of 3 species (creatinine, urea and vitamin B12. Membrane characterization was done using FT-IR spectrophotometer, water absorption test, TG/DTG and SEM. The results showed that the optimum composition PVA:citric acid was obtained to be 90:1, having % WU of 113.74% and creatinine transport percentage of 18.16%. Meanwhile, the optimum composition of chitosan:PVA.cl.CA was found at 4:6 ratio having % WU and % transport of 136.67% and 24.26%, respectively. The optimum transport capacity was found for membrane thickness of 50 µm with WU% at 139.61% and the percent transport of creatinine and urea each was 38.93% and 60.36%. The presence vitamin B12 in the solution of is proved to disturb the transport of creatinine and urea through the membrane. Finally, hydrophilicity seemed to give substantial contribution in the transport process as well as the mechanical strength of the membrane.

  14. Metabolism of Glycerol, Glucose, and Lactate in the Citric Acid Cycle Prior to Incorporation into Hepatic Acylglycerols*

    Science.gov (United States)

    Jin, Eunsook S.; Sherry, A. Dean; Malloy, Craig R.

    2013-01-01

    During hepatic lipogenesis, the glycerol backbone of acylglycerols originates from one of three sources: glucose, glycerol, or substrates passing through the citric acid cycle via glyceroneogenesis. The relative contribution of each substrate source to glycerol in rat liver acylglycerols was determined using 13C-enriched substrates and NMR. Animals received a fixed mixture of glucose, glycerol, and lactate; one group received [U-13C6]glucose, another received [U-13C3]glycerol, and the third received [U-13C3]lactate. After 3 h, the livers were harvested to extract fats, and the glycerol moiety from hydrolyzed acylglycerols was analyzed by 13C NMR. In either fed or fasted animals, glucose and glycerol provided the majority of the glycerol backbone carbons, whereas the contribution of lactate was small. In fed animals, glucose contributed >50% of the total newly synthesized glycerol backbone, and 35% of this contribution occurred after glucose had passed through the citric acid cycle. By comparison, the glycerol contribution was ∼40%, and of this, 17% of the exogenous glycerol passed first through the cycle. In fasted animals, exogenous glycerol became the major contributor to acylglycerols. The contribution from exogenous lactate did increase in fasted animals, but its overall contribution remained small. The contributions of glucose and glycerol that had passed through the citric acid cycle first increased in fasted animals from 35 to 71% for glucose and from 17 to 24% for glycerol. Thus, a substantial fraction from both substrate sources passed through the cycle prior to incorporation into the glycerol moiety of acylglycerols in the liver. PMID:23572519

  15. Metabolism of glycerol, glucose, and lactate in the citric acid cycle prior to incorporation into hepatic acylglycerols.

    Science.gov (United States)

    Jin, Eunsook S; Sherry, A Dean; Malloy, Craig R

    2013-05-17

    During hepatic lipogenesis, the glycerol backbone of acylglycerols originates from one of three sources: glucose, glycerol, or substrates passing through the citric acid cycle via glyceroneogenesis. The relative contribution of each substrate source to glycerol in rat liver acylglycerols was determined using (13)C-enriched substrates and NMR. Animals received a fixed mixture of glucose, glycerol, and lactate; one group received [U-(13)C6]glucose, another received [U-(13)C3]glycerol, and the third received [U-(13)C3]lactate. After 3 h, the livers were harvested to extract fats, and the glycerol moiety from hydrolyzed acylglycerols was analyzed by (13)C NMR. In either fed or fasted animals, glucose and glycerol provided the majority of the glycerol backbone carbons, whereas the contribution of lactate was small. In fed animals, glucose contributed >50% of the total newly synthesized glycerol backbone, and 35% of this contribution occurred after glucose had passed through the citric acid cycle. By comparison, the glycerol contribution was ~40%, and of this, 17% of the exogenous glycerol passed first through the cycle. In fasted animals, exogenous glycerol became the major contributor to acylglycerols. The contribution from exogenous lactate did increase in fasted animals, but its overall contribution remained small. The contributions of glucose and glycerol that had passed through the citric acid cycle first increased in fasted animals from 35 to 71% for glucose and from 17 to 24% for glycerol. Thus, a substantial fraction from both substrate sources passed through the cycle prior to incorporation into the glycerol moiety of acylglycerols in the liver.

  16. Phenotypes of gene disruptants in relation to a putative mitochondrial malate-citrate shuttle protein in citric acid-producing Aspergillus niger.

    Science.gov (United States)

    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.

  17. Olodaterol attenuates citric acid-induced cough in naive and ovalbumin-sensitized and challenged guinea pigs.

    Directory of Open Access Journals (Sweden)

    Eva Wex

    Full Text Available 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

  18. Which way does the citric acid cycle turn during hypoxia? The critical role of α-ketoglutarate dehydrogenase complex.

    Science.gov (United States)

    Chinopoulos, Christos

    2013-08-01

    The citric acid cycle forms a major metabolic hub and as such it is involved in many disease states involving energetic imbalance. In spite of the fact that it is being branded as a "cycle", during hypoxia, when the electron transport chain does not oxidize reducing equivalents, segments of this metabolic pathway remain operational but exhibit opposing directionalities. This serves the purpose of harnessing high-energy phosphates through matrix substrate-level phosphorylation in the absence of oxidative phosphorylation. In this Mini-Review, these segments are appraised, pointing to the critical importance of the α-ketoglutarate dehydrogenase complex dictating their directionalities. Copyright © 2013 Wiley Periodicals, Inc.

  19. The regulatory effect of citric acid on the co-production of poly(ε-lysine) and poly(L-diaminopropionic acid) in Streptomyces albulus PD-1.

    Science.gov (United States)

    Xia, Jun; Xu, Zhaoxian; Xu, Hong; Feng, Xiaohai; Bo, Fangfang

    2014-10-01

    Streptomyces albulus PD-1 can co-produce antimicrobial homo-polymers poly(ε-lysine) (ε-PL) and poly(L-diaminopropionic acid) (PDAP). In this study, a novel feeding strategy of citric acid coupled with glucose-(NH4)2SO4 feeding was employed to S. albulus PD-1. When the pH of the culture broth dropped to 4.0, the feeding solution was added continuously to maintain the concentrations of glucose and citric acid at 10 and 4 g L(-1), respectively. As a result, the final concentration of ε-PL increased from 21.7 to 29.7 g L(-1) and the final concentration of PDAP decreased from 4.8 to 3.2 g L(-1). Assays on intracellular nucleotide levels and key enzyme activities were performed to elucidate the underlying regulation mechanism. The addition of citric acid increased NADH/NAD(+) ratio and decreased intracellular ATP level; meanwhile, the activities of pyruvate kinase, citrate synthase and isocitrate dehydrogenase decreased while aspartate aminotransferase activity increased. Therefore, we deduced that citric acid feeding resulted in metabolic flux redistribution at the node of phosphoenolpyruvate; the metabolic pathway from phosphoenolpyruvate directed into tricarboxylic acid cycle was weakened and thus PDAP production was inhibited. On the other hand, the metabolic pathway from phosphoenolpyruvate directed into oxaloacetate and L-aspartate was enhanced, thereby improving ε-PL production. This fermentation strategy may be potentially useful in ε-PL production because it can effectively inhibit the formation of by-products, such as PDAP.

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

    Science.gov (United States)

    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.

  1. Pulse electrodeposition of Pt and Pt–Ru methanol-oxidation nanocatalysts onto carbon nanotubes in citric acid aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Chou, Huei-Yu [Department of Engineering and System Science, National Tsing Hua University, Hsinchu 30013, Taiwan, ROC (China); Hsieh, Chien-Kuo [Department of Materials Engineering, Ming Chi University of Technology, New Taipei City 24301, Taiwan, ROC (China); Tsai, Ming-Chi; Wei, Yu-Hsuan; Yeh, Tsung-Kuang [Department of Engineering and System Science, National Tsing Hua University, Hsinchu 30013, Taiwan, ROC (China); Tsai, Chuen-Horng, E-mail: tsai@aec.gov.tw [Department of Engineering and System Science, National Tsing Hua University, Hsinchu 30013, Taiwan, ROC (China)

    2015-06-01

    In this study, platinum nanoparticle/carbon nanotube (Pt NP/CNT) and platinum–ruthenium nanoparticle (Pt–Ru NP/CNT) hybrid nanocatalysts were prepared by the pulse-electrodeposition method in different aqueous solutions containing citric acid (CA) or sulfuric acid (SA). The electrocatalytic properties of the Pt NP/CNT and Pt–Ru NP/CNT electrodes prepared using different aqueous solutions were investigated for methanol oxidation. The results show that the electrochemical mass activities of these hybrid nanocatalysts prepared in the CA aqueous solution were increased by factors of 1.46 and 2.77 for Pt NPs and Pt–Ru NPs, respectively, compared with those prepared in SA aqueous solutions using the same procedure. These increased mass activities are attributed to the CA playing dual roles as both a stabilizing agent and a particle size reducing agent in the aqueous solutions. The approach developed in this work enables further reductions in the particle sizes of noble-metal nanocatalysts. - Highlights: • Pulse-electrodeposition of Pt or Pt–Ru nanoparticles on carbon nanotubes • Carbon nanotubes used as a catalyst-supporting material • Citric acid used as reducing agent in the aqueous electrodeposition solutions • Electrochemical activity for methanol oxidation improved by a factor of 1.46 to 2.77.

  2. Antifungal activity of 4-substituted crotonic acid esters.

    Science.gov (United States)

    Gershon, H; Shanks, L; Gawiak, D E

    1976-08-01

    Twenty-three 4-substituted crotonic acid esters were tested for antifungal activity against Candida albicans, Aspergillus niger, Mucor mucedo, and Trichophyton mentagrophytes. For the analogues of the methyl ester containing substituents in the 4 position, the following order of fungitoxicity was observed: I greater than Br greater than Cl greater than CH3S greater than CH3O greater than F=H. Of the homologues of the esters of the 4-iodo and 4-bromo compounds which included methyl, ethyl, n-propyl, n-butyl, n-pentyl, and n-hexyl, ethyl 4-iodocrotonate was most toxic to the four fungi at pH 7.0 in the presence of 10% beef serum (C. albicans, 18mug/ml, A. niger, 40 mug/ml, M. mucedo, 5 mug/ml, T. mentagrophytes, 4 mug/ml). It is believed that the mechanism of fungitoxicity is due, in part, to a nucleophilic reaction involving SH-containing compounds. This is based on the correlation of fungitoxicity with the order of leaving groups in the nucleophilic reaction and the protection against the toxicity of the test compounds to the fungi by cysteine and glutathione.

  3. Citric acid production from hydrolysate of pretreated straw cellulose by Yarrowia lipolytica SWJ-1b using batch and fed-batch cultivation.

    Science.gov (United States)

    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.

  4. Optimization of Initial pH and Total Sugar Concentration Variables on Citric Acid Production from Pineapple Waste with Aspergillus niger Yeast by Using Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    Widayat Widayat

    2011-06-01

    Full Text Available Citric acid can be produced from pineapple waste by using fermentation process. This process is done in bubble column reactor with Aspergillus niger yeast. The objective of this research is to find the optimum conditions of initial pH and total sugar concentration. The optimization method used was response surface methodology. This research was carried out at a temperature of 30 oC, spore concentration of 1.23 x 109 spore/ml, total volume 2.0 liter, flow rate of air 58.07 cc/sec and a 5% antifoam concentration. The fermentation process lasted 7 days and the citric acid concentration was analyzed by High Pressure Liquid Cromatography (HPLC method. Statistica 6 software was used for the data treatment. The mathematical model for the optimization citric acid fermentation in bubble column reactor is Y = 54.507 + 2.9851X - 8.987X12 - 2.581X2 - 15.446X22 - 7.989X1X2 The parameter of Y is citric acid yield, X1 is a coding initial pH and X2 is a coding total sugar concentration. The results has given an initial pH optimum 3.61 and total sugar concentration 19,285% w/v with optimum an yield of 55.03 % . Keywords: Bubble column bioreactor, Citric acid fermentation, Initial pH, Total sugar concentration, Response surface methodology

  5. Enhancing the reactivity of bimetallic Bi/Fe{sup 0} by citric acid for remediation of polluted water

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Jianyu; Lee, Chung-Seop; Kim, Eun-Ju [School of Environmental Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang 790-784 (Korea, Republic of); Chang, Yoon-Young [Department of Environmental Engineering, Kwangwoon University, Seoul 139-701 (Korea, Republic of); Chang, Yoon-Seok, E-mail: yschang@postech.ac.kr [School of Environmental Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang 790-784 (Korea, Republic of)

    2016-06-05

    Highlights: • A novel bismuth modified zero valent iron (Bi/Fe{sup 0}) was synthesized. • The Bi/Fe{sup 0} + CA(citric acid) + O{sub 2} system could produce ·OH and ·O{sub 2}{sup −}. • Some recalcitrant pollutants could be treated by Bi/Fe{sup 0} + CA + O{sub 2} in a short time. • The formation of Fe(III)-citric results in the generation of ·OH and ·O{sub 2}{sup −}. - Abstract: In this study, the environmentally benign citric acid (CA) was utilized to improve the aerobic degradation of 4-chlorophenol (4-CP) over bismuth modified nanoscale zero-valent iron (Bi/Fe{sup 0}). The characterization results revealed the existence of bismuth covering on the Fe{sup 0} surface under zero-valent state. And, the Bi/Fe{sup 0}-CA + O{sub 2} system performed excellent reactivity in degradation of 4-CP due to the generation of reactive oxygen species (ROS), which was confirmed by electron spin resonance (ESR) spectroscopy. After 30 min of reaction, 80% of 4-CP was removed using Bi/Fe{sup 0}-CA + O{sub 2} accompanying with high dechlorination rate. The oxidative degradation intermediates were analyzed by HPLC and LC-MS. We found that CA could promote the bismuth-iron system to produce much reactive oxygen species ROS under both aerobic and anaerobic conditions due to its ligand function, which could react with Fe{sup 3+} to form a ligand complex (Fe(III)Cit), accompanying with a considerable production of Fe{sup 2+} and H{sub 2}O{sub 2}. This study provides a new strategy for generating ROS on nZVI and suggests its application for the mineralization of many recalcitrant pollutants.

  6. 40 CFR 721.10142 - Oxabicycloalkane carboxylic acid alkanediyl ester (generic).

    Science.gov (United States)

    2010-07-01

    ... alkanediyl ester (generic). 721.10142 Section 721.10142 Protection of Environment ENVIRONMENTAL PROTECTION... ester (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as oxabicycloalkane carboxylic acid alkanediyl ester (PMN P-06-199)...

  7. 40 CFR 721.6075 - Phosphonic acid, 1,1-methylenebis-tetrakis(1-methylethyl) ester.

    Science.gov (United States)

    2010-07-01

    ...-tetrakis(1-methylethyl) ester. 721.6075 Section 721.6075 Protection of Environment ENVIRONMENTAL PROTECTION...-methylethyl) ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as phosphonic acid, 1,1-methylenebis-tetrakis(1-methylethyl) ester (PMN P-95-168)...

  8. 40 CFR 721.1728 - Benzoic acid, 2-(3-phenylbutylidene)amino-, methyl ester.

    Science.gov (United States)

    2010-07-01

    ...)amino-, methyl ester. 721.1728 Section 721.1728 Protection of Environment ENVIRONMENTAL PROTECTION...-, methyl ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as benzoic acid, 2-(3-phenylbutylidene)amino-, methyl ester (PMN P-85-1211) is...

  9. 40 CFR 721.1875 - Boric acid, alkyl and substituted alkyl esters (generic name).

    Science.gov (United States)

    2010-07-01

    ... alkyl esters (generic name). 721.1875 Section 721.1875 Protection of Environment ENVIRONMENTAL... esters (generic name). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance boric acid, alkyl and substituted alkyl esters (PMN P-86-1252) is subject to reporting...

  10. 柠檬酸对动物的生物学作用研究%Study on biological actions of citric acid in animals

    Institute of Scientific and Technical Information of China (English)

    史彬林; 王淑琴

    2016-01-01

    Citric acid is a kind of organic acids and has some good physical and chemical natures, and so can be applied in animal diets. The paper summarized the biological actions of citric acid in ani⁃mals, in order to supply references for scientific application of citric acid in animal production.%柠檬酸是一种重要的有机酸,具有良好的物理和化学性能,可作为酸化剂在动物日粮中应用。文章综述了日粮中添加柠檬酸对动物生产性能、消化吸收、免疫功能等方面的生物学作用,为其在动物生产中的科学应用提供参考。

  11. ESTIMATION OF HYDROLYSIS RATE CONSTANTS OF CARBOXYLIC ACID ESTER AND PHOSPHATE ESTER COMPOUNDS IN AQUEOUS SYSTEMS FROM MOLECULAR STRUCTURE BY SPARC

    Science.gov (United States)

    SPARC (SPARC Performs Automated Reasoning in Chemistry) chemical reactivity models were extended to calculate hydrolysis rate constants for carboxylic acid ester and phosphate ester compounds in aqueous non- aqueous and systems strictly from molecular structure. The energy diffe...

  12. Synthesis of N-(methoxycarbonyl or isopropylcarbamoyl- methoxyphosphonyl)-α-amino acid ester and their stereomers

    Institute of Scientific and Technical Information of China (English)

    陈茹玉; 李慧英

    1996-01-01

    N-(methoxycarbonyl-methoxyphosphonyl)-α-amino add esters (I) were synthesized via the reaction of the corresponding phosphonyl chloride with amino acid ester hydrochlorides in the presence of a base. Compound I was aminated to yield N-(isopropylcarbainoyl-methoxyphosphonyl)-α-amino acid esters (II). With l-amino acids as starting materials, the isomers of products I and II were separated and their configurations were confirmed by the single crystal X-ray diffraction of II.

  13. A Convenient, General Synthesis of 1,1-Dimethylallyl Esters as Protecting Groups for Carboxylic Acids

    Science.gov (United States)

    Sedighi, Minoo; Lipton, Mark A.

    2006-01-01

    Carboxylic acids were converted in high yield to their 1,1-dimethylallyl (DMA) esters in two steps. Palladium-catalyzed deprotection of DMA esters was shown to be compatible with tert-butyl, benzyl and Fmoc protecting groups, and Fmoc deprotection could be carried out selectively in the presence of DMA esters. DMA esters were also shown to be resistant to nucleophilic attack, suggesting that they will serve as alternatives to tert-butyl esters when acidic deprotection conditions need to be avoided. PMID:15816730

  14. A convenient, general synthesis of 1,1-dimethylallyl esters as protecting groups for carboxylic acids.

    Science.gov (United States)

    Sedighi, Minoo; Lipton, Mark A

    2005-04-14

    [reaction: see text] Carboxylic acids were converted in high yield to their 1,1-dimethylallyl (DMA) esters in two steps. Palladium-catalyzed deprotection of DMA esters was shown to be compatible with tert-butyl, benzyl, and Fmoc protecting groups, and Fmoc deprotection could be carried out selectively in the presence of DMA esters. DMA esters were also shown to be resistant to nucleophilic attack, suggesting that they will serve as alternatives to tert-butyl esters when acidic deprotection conditions need to be avoided.

  15. Poly(citric acid)-block-poly(ethylene glycol) copolymers--new biocompatible hybrid materials for nanomedicine.

    Science.gov (United States)

    Naeini, Ashkan Tavakoli; Adeli, Mohsen; Vossoughi, Manouchehr

    2010-08-01

    Linear-dendritic ABA triblock copolymers containing poly(ethylene glycol) (PEG) as B block and hyperbranched poly(citric acid) (PCA) as A blocks were synthesized through polycondensation. The molecular self-assembly of synthesized PCA-PEG-PCA copolymers in water led to formation of nanoparticles and fibers in different sizes and shapes depending on the time and size of PCA blocks. Ten days after dissolving PCA-PEG-PCA copolymers in water, the size of fibers had reached several millimeters. Mixing a water solution of fluorescein as a small guest molecule and PCA-PEG-PCA copolymers led to the encapsulation of fluorescein by products of molecular self-assembly. To investigate their potential application in nanomedicine and to understand the limitations and capabilities of these materials as nanoexcipients in biological systems, different types of short-term in vitro cytotoxicity experiments on the HT1080 cell line (human fibrosarcoma) and hemocompatibility tests were performed. From the clinical editor: This manuscript investigates the potentials of linear-dendritic ABA triblock copolymers containing poly(ethylene glycol) (PEG) as B block and hyperbranched poly(citric acid) (PCA) as A blocks for future applications in nanomedicine.

  16. The mixture of liquid foam soap, ethanol and citric acid as a new fixative-preservative solution in veterinary anatomy.

    Science.gov (United States)

    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.

  17. Cassava starch coating and citric acid to preserve quality parameters of fresh-cut "Tommy Atkins" mango.

    Science.gov (United States)

    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.

  18. Decontamination of Anodized Implant Surface With Different Modalities for Peri-Implantitis Treatment: Lasers and Mechanical Debridement With Citric Acid.

    Science.gov (United States)

    Htet, Moe; Madi, Marwa; Zakaria, Osama; Miyahara, Takayuki; Xin, Wang; Lin, Zayar; Aoki, Kazuhiro; Kasugai, Shohei

    2016-08-01

    Although oral rehabilitation with dental implants is a very promising and effective procedure, peri-implantitis is an emerging concern. Surgical and non-surgical methods have been applied to treat peri-implantitis together with various implant surface decontamination methods. However, there is no consensus concerning the most effective treatment for peri-implantitis. The aim of the present study is to evaluate the effects of erbium-doped:yttrium, aluminum, and garnet (Er:YAG) laser, photodynamic therapy (PDT), and titanium bur with and without citric acid on ligature-induced peri-implantitis around an anodized implant surface. Thirty dental implants with anodized surface (3.3 × 10 mm) were installed in the mandibles of five beagle dogs. After 3 months, peri-implantitis was induced by applying cotton ligatures subgingivally. After ligature removal (baseline), the implants were divided into the following treatment groups: 1) Er:YAG laser, 2) PDT, 3) titanium bur alone, and 4) titanium bur with citric acid. Animals were sacrificed after 3 months, and clinical, radiologic, histologic, and histomorphometric evaluations were conducted for all treatment modalities. The data were analyzed using one-way analysis of variance and Tukey test. A value of P implant contact than the PDT group and the bur-alone group. Within the limits of the study, the combination of mechanical and chemical treatment proved to be the most effective treatment for disinfection of the anodized implant surface.

  19. Biodegradable and non-retrogradable eco-films based on starch-glycerol with citric acid as crosslinking agent.

    Science.gov (United States)

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

    2016-03-15

    Biodegradable and non-retrogradable starch-glycerol based films were obtained using citric acid (CA) as crosslinking agent at 75°C. This material allowed decreasing water vapor permeability (WVP) more than 35%, remained amorphous for at least 45 days as a result of the network formed by the CA that avoided starch retrogradation and maintained the degradability in compost, occurring only six days after the films without citric acid. A simulation of the gelatinization process of starch-glycerol with and without CA, using a differential thermal analysis device, showed that the system with CA completed the gelatinization 5°C before than the other and, CA first reacted with glycerol and then starch-glycerol-CA reaction occurred. The temperature at which the gelatinization process was carried out was critical to obtain the best results. An increase of gelatinization process temperature at 85°C in system with CA, led to a worsening on WVP and its integrity after a swelling process with dimethylsulphoxide (DMSO), compared to the films processed at 75°C.

  20. Application of natural citric acid sources and their role on arsenic removal from drinking water: a green chemistry approach.

    Science.gov (United States)

    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.