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Sample records for citric acid

  1. 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.

  2. Citric acid urine test

    Science.gov (United States)

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

  3. 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

  4. 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.

  5. Microbial production of citric acid

    Directory of Open Access Journals (Sweden)

    Luciana P. S Vandenberghe

    1999-01-01

    Full Text Available Citric acid is the most important organic acid produced in tonnage and is extensively used in food and pharmaceutical industries. It is produced mainly by submerged fermentation using Aspergillus niger or Candida sp. from different sources of carbohydrates, such as molasses and starch based media. However, other fermentation techniques, e.g. solid state fermentation and surface fermentation, and alternative sources of carbon such as agro-industrial residues have been intensively studied showing great perspective to its production. This paper reviews recent developments on citric acid production by presenting a brief summary of the subject, describing micro-organisms, production techniques, and substrates, etc.O ácido cítrico é o ácido mais produzido em termos de tonagem e é extensivamente utilizado pelas indústrias alimentícia e farmacêutica. É produzido principalmente por fermentação submersa utilizando o fungo Aspergillus niger e leveduras do gênero Candida sp. à partir de diferentes fontes de carbono, como a glicose e meios à base de amido. No entanto, outras técnicas de fermentação, e.g. fermentação no estado sólido e em superfície, e fontes alternativas de carbono tem sido intensamente estudadas mostrando grande perspectivas para o processo. O presente trabalho apresenta um resumo dos últimos avanços sobre a produção do ácido cítrico, descrevendo de maneira sucinta os trabalhos mais recentes, descrevendo microrganismos, técnicas de produção e substratos empregados, etc.

  6. 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.

  7. CITRIC ACID PRODUCTION USING FERMENTATION TECHNOLOGY

    OpenAIRE

    ANKIT KUMAR; OM PRAKASH VERMA

    2007-01-01

    Citric acid, C3H4OH(COOH)3, (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 o...

  8. 21 CFR 184.1033 - Citric acid.

    Science.gov (United States)

    2010-04-01

    ... the specifications of the Food Chemicals Codex, 3d ed. (1981), pp. 86-87, and its third supplement... CFR part 51. Copies are available from the National Academy Press, 2101 Constitution Ave. NW... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Citric acid. 184.1033 Section 184.1033 Food...

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

    Science.gov (United States)

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

  10. Biotransformation of plutonium complexed with citric acid

    Energy Technology Data Exchange (ETDEWEB)

    Francis, A.J.; Dodge, C.J.; Gillow, J.B. [Environmental Sciences Department, Brookhaven National Laboratory, Upton, New York, 11973 (United States)

    2005-07-01

    Full text of publication follows: The presence of organic ligands in radioactive wastes is a major concern because of the potential for increasing the transport of radionuclides from disposal sites. Microorganisms present in radioactive wastes can affect the long-term stability of radionuclides associated with organic ligands. Biotransformation of radionuclides complexed with organic ligands should result in the precipitation of the radionuclides and retard their migration. In this study we investigated the biotransformation of {sup 242}Pu{sup 4+} (10{sup -8} to 10{sup -5} M) in the presence of equimolar and excess citric acid by Pseudomonas fluorescens. Analysis of {sup 242}Pu-citrate by electro-spray ionization-mass spectrometry (ESI-MS) indicated the presence of a bi-ligand Pu-cit{sub 2} complex. Analysis of Th-citrate complex, an analog for Pu-citrate, indicated the formation of a 2:3 complex. Citric acid under aerobic conditions was metabolized by P. fluorescens at a rate of 4.9 {mu}M/h, and decreased to 4.0 and 3.8 {mu}M/h in the presence of 10{sup -8} and 10{sup -6} M of Pu, respectively. The pH of the medium containing citric acid alone increased from 6.5 to 7.1, while the pH of the samples containing Pu increased from 6.8 to 7.9. The high ionic strength (0.9 M) of the medium reduced citric acid metabolism by 50% in comparison to 0.1 M ionic strength. Initially, Pu added to the growth medium as Pu-citrate remained in solution as Pu{sup 4+}. Selective solvent extraction by thenyl-tri-fluoro-acetone (TTA) as well as micro-filtration (0.03 {mu}m) of the medium after biodegradation studies indicated that Pu was present as the polymeric form. The Pu polymer formation was dependent on the Pu:citrate ratio as well as the extent of citrate metabolism. The high ionic strength solution containing 10{sup -5} M 1:1 Pu-citrate complex showed only 27% citrate degradation but had the highest percentage ({approx}80%) of polymer formation, suggesting the Pu was soluble only

  11. Biotransformation of plutonium complexed with citric acid

    International Nuclear Information System (INIS)

    Full text of publication follows: The presence of organic ligands in radioactive wastes is a major concern because of the potential for increasing the transport of radionuclides from disposal sites. Microorganisms present in radioactive wastes can affect the long-term stability of radionuclides associated with organic ligands. Biotransformation of radionuclides complexed with organic ligands should result in the precipitation of the radionuclides and retard their migration. In this study we investigated the biotransformation of 242Pu4+ (10-8 to 10-5 M) in the presence of equimolar and excess citric acid by Pseudomonas fluorescens. Analysis of 242Pu-citrate by electro-spray ionization-mass spectrometry (ESI-MS) indicated the presence of a bi-ligand Pu-cit2 complex. Analysis of Th-citrate complex, an analog for Pu-citrate, indicated the formation of a 2:3 complex. Citric acid under aerobic conditions was metabolized by P. fluorescens at a rate of 4.9 μM/h, and decreased to 4.0 and 3.8 μM/h in the presence of 10-8 and 10-6 M of Pu, respectively. The pH of the medium containing citric acid alone increased from 6.5 to 7.1, while the pH of the samples containing Pu increased from 6.8 to 7.9. The high ionic strength (0.9 M) of the medium reduced citric acid metabolism by 50% in comparison to 0.1 M ionic strength. Initially, Pu added to the growth medium as Pu-citrate remained in solution as Pu4+. Selective solvent extraction by thenyl-tri-fluoro-acetone (TTA) as well as micro-filtration (0.03 μm) of the medium after biodegradation studies indicated that Pu was present as the polymeric form. The Pu polymer formation was dependent on the Pu:citrate ratio as well as the extent of citrate metabolism. The high ionic strength solution containing 10-5 M 1:1 Pu-citrate complex showed only 27% citrate degradation but had the highest percentage (∼80%) of polymer formation, suggesting the Pu was soluble only in the presence of excess citric acid. However, the extensive

  12. 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.

  13. Submerged citric acid fermentation on orange peel autohydrolysate.

    Science.gov (United States)

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

    2008-04-01

    The citrus-processing industry generates in the Mediterranean area huge amounts of orange peel as a byproduct from the industrial extraction of citrus juices. To reduce its environmental impact as well as to provide an extra profit, this residue was investigated in this study as an alternative substrate for the fermentative production of citric acid. Orange peel contained 16.9% soluble sugars, 9.21% cellulose, 10.5% hemicellulose, and 42.5% pectin as the most important components. To get solutions rich in soluble and starchy sugars to be used as a carbon source for citric acid fermentation, this raw material was submitted to autohydrolysis, a process that does not make use of any acidic catalyst. Liquors obtained by this process under optimum conditions (temperature of 130 degrees C and a liquid/solid ratio of 8.0 g/g) contained 38.2 g/L free sugars (8.3 g/L sucrose, 13.7 g/L glucose, and 16.2 g/L fructose) and significant amounts of metals, particularly Mg, Ca, Zn, and K. Without additional nutrients, these liquors were employed for citric acid production by Aspergillus niger CECT 2090 (ATCC 9142, NRRL 599). Addition of calcium carbonate enhanced citric acid production because it prevented progressive acidification of the medium. Moreover, the influence of methanol addition on citric acid formation was investigated. Under the best conditions (40 mL of methanol/kg of medium), an effective conversion of sugars into citric acid was ensured (maximum citric acid concentration of 9.2 g/L, volumetric productivity of 0.128 g/(L.h), and yield of product on consumed sugars of 0.53 g/g), hence demonstrating the potential of orange peel wastes as an alternative raw material for citric acid fermentation. PMID:18321055

  14. Simulation of citric acid production by rotating disk contactor.

    Science.gov (United States)

    Sakurai, A; Imai, H; Takenaka, Y; Sakakibara, M

    1997-12-20

    A simple model was presented to describe the time courses of citric acid production by a rotating disc contactor (RDC) using Aspergillus niger. The model is expressed by Monod-type cell growth, Luedeking-Piret-type citric acid production rate equations, and the diffusion equation for oxygen in the biofilm. The model contains five parameters which were determined by the nonlinear least squares method by fitting the numerical solution to the experimental data. In solving the equations, the cell density of the biofilm was estimated from the value of cellular mass per unit of biofilm area using an empirical equation. The experimental time courses in citric acid production period were well simulated with this model. The relation between the specific biofilm surface area and the rate of citric acid production was also explained by the simulation using the average values of five parameters of twelve runs. (c) 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 56: 689-696, 1997. PMID:18642341

  15. 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.

  16. Citric Acid Treatment of Chronic Wounds in Animals

    Directory of Open Access Journals (Sweden)

    B.S. Nagoba,

    2011-02-01

    Full Text Available Chronic wound infections in animals not responding to conventional treatment modality are the important cause of morbidity. Infection is responsible for delayed wound healing. In the present study, an attempt was made to develop simple and effective treatment modality by using citric acid as a sole antimicrobial agent to control chronic wound infections in animals. Thirty eight cases of chronic wounds not responding to conventional treatment modalities were divided into two groups. Each group included 19 cases. In group 1, 3% citric acid solution and in group 2, 5% citric acid solution was used for local application to find out its efficacy in the treatment of chronic wound infections in animals. Citric acid was found effective in the control of all 38 cases in 7 to 20 applications. In group 1, the wounds healed in 10-20 applications. In group 2, the wounds healed in 7-15 applications. Citric acid treatment was found most effective and economical approach for the successful treatment of chronic infected wounds in animals not responding to conventional antibiotic treatment and local wound care. These results suggest that when healing of chronic wounds in animals is a matter of great concern, the value of topical agents like citric acid should not be forgotten.

  17. Use of citric acid for large parts decontamination

    International Nuclear Information System (INIS)

    Laboratory and field studies have been performed to identify and evaluate chemical decontamination agents to replace ammonium carbonate, an environmentally unacceptable compound, in the decontamination facility for large process equipment at the Portsmouth Gaseous Diffusion Plant. Preliminary screening of over 40 possible decontamination agents on the basis of efficiency, availability, toxicity, cost, corrosiveness, and practicality indicated sodium carbonate and citric acid to be the most promising. Extensive laboratory studies were performed with these two reagents. Corrosion rates, decontamination factors, uranium recovery efficiencies, technetium (99Tc)/ion exchange removal effects, and possible environmental impacts were determined or investigated. Favorable results were found in all areas. Detailed monitoring and analysis during two-week trial periods in which sodium carbonate and citric acid were used in the large parts decontamination facility resulted in similar evaluation and conclusions. Because it has cleaning properties not possessed by sodium carbonate, and because it eliminated several operational problems by incorporating two acidic decontamination reagents (citric and nitric acids) instead of one basic reagent (sodium or ammonium carbonate) and one acidic reagent (nitric acid), citric acid was selected for one-year field testing. On the basis of its excellent performance in the field tests, citric acid is recommended as a permanent replacement for ammonium carbonate in the decontamination facility for large process equipment

  18. 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. PMID:23490185

  19. 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

  20. 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. PMID:25898079

  1. 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.

  2. Electrochemical monitoring of citric acid production by Aspergillus niger

    International Nuclear Information System (INIS)

    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

  3. 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.

  4. Citric Acid Treatment of Chronic Wounds in Animals

    OpenAIRE

    B.S. Nagoba,; B.J. Wadher and S.P. Selkar

    2011-01-01

    Chronic wound infections in animals not responding to conventional treatment modality are the important cause of morbidity. Infection is responsible for delayed wound healing. In the present study, an attempt was made to develop simple and effective treatment modality by using citric acid as a sole antimicrobial agent to control chronic wound infections in animals. Thirty eight cases of chronic wounds not responding to conventional treatment modalities were divided into two groups. Each group...

  5. Decontamination effectiveness of mixtures of citric acid, oxalic acid and EDTA

    International Nuclear Information System (INIS)

    An experimental study of the decontamination effectiveness of citric acid, oxalic acid and EDTA mixtures was conducted to assess whether oxalic acid could be removed from decontamination solutions to minimize corrosion. In loop experiments, radioactive specimens from two boiling water reactors and one pressurized water reactor were suspended in solutions of single acids or in mixtures of reagents at total reagent concentrations of less than 0.1 wt% under conditions similar to those used to decontaminate reactor systems. Rate constants for dissolution of oxides and decontamination factors were measured. Based on the results, it was concluded that under certain conditions, oxalic acid was the most effective reagent for the dissolution of oxides. It was also found, however, that conditions under which effective dissolution occurred in solutions of oxalic acid and/or citric acid were difficult to define and control. EDTA was found to be an effective reagent for dissolution of oxides such that rates of dissolution in EDTA containing solutions at 117 degrees Celsius were comparable to rates in oxalic acid containing solutions. At 90 degrees Celsius, EDTA acted synergistically with oxalic acid such that the rate of dissolution of oxides in citric-acid/oxalic-acid/EDTA solutions was higher than in citric-acid/EDTA solutions. The rates of dissolution of oxides were significantly reduced when 60 mg/kg of ferric ion was added to the citric-acid/oxalic-acid, citric-acid/EDTA and citric-acid/oxalic-acid/EDTA solutions. It was concluded that effective decontaminations of BWR and PWR systems could be achieved with mixtures of citric acid and EDTA

  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. PMID:24522611

  7. 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. PMID:27044343

  8. Detection of exogenous citric acid in fruit juices by stable isotope ratio analysis.

    Science.gov (United States)

    Jamin, Eric; Martin, Frédérique; Santamaria-Fernandez, Rebeca; Lees, Michèle

    2005-06-29

    A new method has been developed for measuring the D/H ratio of the nonexchangeable sites of citric acid by isotope ratio mass spectrometry (IRMS). Pure citric acid is transformed into its calcium salt and subsequently analyzed by pyrolysis-IRMS. The citric acid isolated from authentic fruit juices (citrus, pineapple, and red fruits) systematically shows higher D/H values than its nonfruit counterpart produced by fermentation of various sugar sources. The discrimination obtained with this simplified method is similar to that obtained previously by applying site specific isotopic fractionation-nuclear magnetic resonance (SNIF-NMR) to an ester derivative of citric acid. The combination of carbon 13 and deuterium measurements of extracted citric acid is proposed as a routine method for an optimum detection of exogenous citric acid in all kinds of fruit juices. PMID:15969486

  9. 7 CFR 51.1178 - Maximum anhydrous citric acid permissible for corresponding total soluble solids.

    Science.gov (United States)

    2010-01-01

    ... of Florida Oranges and Tangelos Standards for Internal Quality of Common Sweet Oranges (citrus... solids. For determining the grade of juice, the maximum permissible anhydrous citric acid content...

  10. Quantification of uranyl in presence of citric acid

    International Nuclear Information System (INIS)

    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. Reconsideration in Using Citric Acid as Vase Solution Preservative for Cut Rose Flowers

    Directory of Open Access Journals (Sweden)

    Mohammad Mahdi Jowkar

    2012-07-01

    Full Text Available The major cause of vase life reduction in cut flowers is water relation interruption which is mostly due to vase solution microbial proliferation and consequently vascular occlusion resulting in solution uptake reduction. In order to reduce vase solution microbial count, most preservatives incorporate acidifying agents mostly citric acid. Beside microbial proliferation control, biocides could affect cut flower’s quality and physiology in various aspects. In order to study the biocidal effect of citric acid, ‘Cherry Brandy’ roses were treated in a completely randomized design with: citric acid (300, 600 and 900 mg/L, respectively or sterilized distilled water (control. Effects of citric acid application as vase solution biocide and its impact on vase life, water relation, vase solution microbial kind and population beside different physiological parameters such as chlorophyll degradation, chlorophyll fluorescence and membrane permeability were investigated during this study. Results indicated that citric acid increased vase life (although insignificantly and amazingly its’ application resulted in better fresh appearance during last days of vase life. Although microbial control was not desirable, but it was achieved to some extent by citric acid application. Citric acid resulted in higher fresh weight increment. But fresh weight was lost more rapidly compared to control. This was while citric acid treated flowers had lower solution up take at most stages of vase life. Five different micro-organisms were observed in citric acid vase solutions which were: 2 strains of Fusarium solani and three isolates of Bacillus, Coccus and Streptomyces sp. Ion leakage trend showed a steady increase during vase life and was significantly increased by citric acid application during the last days of vase life as membrane permeability and vase life decrease. Citric acid significantly increased leaf chlorophyll content of treated flowers while it resulted in

  12. Relationship of Quantity of Citric Acid and Protein Content of Mycelia during Citric Acid Production by Three Strains of Aspergillus niger

    International Nuclear Information System (INIS)

    The amount of protein in the surface grown mycelia of three strains of Aspergillus niger (CA16,79/20 and 318) was found to decrease with the increase of citric acid production in sucrose based fermentation medium. Throughout the study period of 6 to 10 days of fermentation, highest amount of citric acid was produced by Aspergillus niger 318 although the amount of protein in mycelia was lowest for this strain. On the other hand, lowest amount of citric acid was produced by the strain CA 16 which in tern produced highest amount of mycelial protein. Aspergillus niger 79/20 produced both intermediate level of protein and citric acid. The Protein was estimated by three commonly used methods namely: Kjeldahl, Biuret and Lowry methods. Kjeldahl and Lowry method gave the highest and lowest results respectively for protein determination in all cases.(authors)

  13. Citric acid production by gamma irradiated aspergillus niger from treated beet molasses under different fermentation conditions

    International Nuclear Information System (INIS)

    The necessary treatments of beet molasses by addition of any the chelating agents potassium ferrocyanide and ethylenediamine tetraacetic acid (EDTA), to improve its suitability as a substrate for citric acid production by gamma irradiated inocula (at dose 0.4 KGy) of aspergillus niger EMCC 111 was studied. Addition of potassium ferrocyanide stimulated citric acid production and maximum production (10.92 g%) was obtained with 0.1 g% of ferrocyanide. In contrast, EDTA at 0.1 g% increased citric acid production but further addition of EDTA repressed the production. Addition of low molecular weight alcohols (methanol or ethanol)improved the yield of citric acid. Methanol and ethanol when added at concentration of 2%(v/v) elevate citric acid yield % to 47.58% and 46.51% respectively. 6 tabs

  14. 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.

  15. Biological durability of wood modified by citric acid

    Directory of Open Access Journals (Sweden)

    Bogoslav Šefc

    2008-07-01

    Full Text Available This paper presents the results of measurement of durability of beech wood (Fagus sylvatica modified by Citric Acid (CA against brown rot fungus Poria placenta according to EN 113. Modification was performedby impregnation with 7.0% CA and 6.5% sodium-hypophosphite (SHP water solution and 10-hour curing at 140 °C. The influence of thermal treatment on durability was also researched. Weight percentage gain (WPG caused by modification, moisture content (MC and mass loss of wood (dm after fungal nutrition were measured. WPG of modified beech wood was 6.1% and that of thermally treated wood was -0.3%. The results showed increased durability of modified wood to be 8.3 times greater than nonmodified, while thermal treatment did not give significant durability improvement. These results indicate modification by CA as a promising alternative, but further research on optimisation of modification parameters is needed to achieve improvement of wood properties.

  16. 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. PMID:24840879

  17. 21 CFR 173.280 - Solvent extraction process for citric acid.

    Science.gov (United States)

    2010-04-01

    ... specifications of § 173.165. (d) Residues of n-octyl alcohol and synthetic isoparaffinic petroleum hydrocarbons... isoparaffinic petroleum hydrocarbons in citric acid. (e) Tridodecyl amine may be present as a residue in citric...-octyl alcohol meeting the requirements of § 172.864 of this chapter, synthetic isoparaffinic...

  18. Mutant breeding of Aspergillus niger irradiated by 12C6+ for hyper citric acid

    International Nuclear Information System (INIS)

    In this study, strains of Aspergillus niger No.4 for hyper citric acid were irradiated to different doses by 80 MeV/u 12C6+ ion beams. Seven mutant strains showed marked citric acid over-production records and faster productivity than initial Aspergillus niger No.4 by shaking flash fermentation. The maximum product yield was 132.8 gL-1 (the H4002 strain) being a 8.8% increase to the initial strain. The scale-up experiment was carried out in a 100 L bioreactor. The mutant H4002 can accumulate 187gL-1 product yield of citric acid from starch liquefying supernatant. The productivity of citric acid was 2.75 g L-1 h-1. So, the mutant H4002 possesses rapid sugar katabolism for producing citric acid. Meanwhile, the pellet morphology kept compact and round during the whole submerged fermentation, which was suited to produce citric acid. The results indicate that mutant H4002 has potential ability to produce citric acid rapidly. (authors)

  19. Production of Citric Acid from a New Substrate, Undersized Semolina, by Aspergillus niger

    OpenAIRE

    Alben, Emine; Erkmen, Osman

    2004-01-01

    The production of citric acid from fermentation medium (mass per volume ratio 0.01 % of undersized semolina) by Aspergillus niger was studied by shake culture method. The effects of initial pH (4.5, 5.5 and 6.5), methanol (volume fraction 1.0, 2.0 and 3.0 %) and ammonium nitrate (mass per volume ratio 0.01 %) on the production of citric acid were investigated. Citric acid concentration, biomass concentration and the amount of total carbohydrates (as glucose) were determined during fermentatio...

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

    OpenAIRE

    He, Fu-Yi; Kim, Hyun-Wook; Hwang, Ko-Eun; Song, Dong-Heon; Kim, Yong-Jae; Ham, Youn-Kyung; Kim, Si-Young; Yeo, In-Jun; Jung, Tae-Jun; Kim, Cheon-Jei

    2015-01-01

    The objective of this study was to examine the effect of ginger extract (GE) combined with citric acid on the tenderness of duck breast muscles. Total six marinades were prepared with the combination of citric acid (0 and 0.3 M citric acid) and GE (0, 15, and 30%). Each marinade was sprayed on the surface of duck breasts (15 mL/100 g), and the samples were marinated for 72 h at 4℃. The pH and proteolytic activity of marinades were determined. After 72 h of marination, Warner Bratzler shear fo...

  1. Effect of citric acid on the utilization of olive cake diets for laying hens

    OpenAIRE

    Al-Harthi, Mohammed A.; Youssef A. Attia

    2015-01-01

    The study aims at improving the utilization of olive cake (OC) containing-diets for laying hens by citric acid supplementation at 0.1 and 0.2%. Olive cake was collected and dried by sunny warm air at an average temperature of 45°C with continuous stirring until completely dried. Then, the OC was included in isonutritive diets at 0, 10 and 20%. Additionally, citric acid was added at 0, 0.1 and 0.2%. This resulted in 3(OC levels)×3(citric acid concentrations), producing 9 different treatments. ...

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

    OpenAIRE

    R. Yazdanparast; and A. Bahrani

    1995-01-01

    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 i...

  3. ASSAY OF ASCORBIC ACID BY RP-HPLC IN SAMPLES CONTAINING ALSO CITRIC ACID

    OpenAIRE

    Ostafe, V.; C. Brumaru; Gabriela Papoe; Ioana Lupsa

    1999-01-01

    The ascorbic acid is widely used as antioxidant in food products. As this substance is a very unstable substance, its concentration needs an accurate monitorization. A RP-HPLC method was used for identification and quantification of ascorbic acid in mixtures used in sausage industry. Reliable results are obtained even the samples contain high quantities of citric acid. The regression coefficient of standard curve is 0.999.

  4. ASSAY OF ASCORBIC ACID BY RP-HPLC IN SAMPLES CONTAINING ALSO CITRIC ACID

    Directory of Open Access Journals (Sweden)

    V. Ostafe

    1999-01-01

    Full Text Available The ascorbic acid is widely used as antioxidant in food products. As this substance is a very unstable substance, its concentration needs an accurate monitorization. A RP-HPLC method was used for identification and quantification of ascorbic acid in mixtures used in sausage industry. Reliable results are obtained even the samples contain high quantities of citric acid. The regression coefficient of standard curve is 0.999.

  5. Determination of low citric acid concentrations in a mixture of weak acid/bases

    OpenAIRE

    Lahav, O.; Shlafman, E.; Cochva, M.

    2005-01-01

    A titration approach was developed to measure low concentrations of citric acid (C6H8O7) in a mixture of other weak acid/ bases. Two methods were tested. The first and more practical method (a 4-point titration procedure) is applicable in conditions where volatile fatty acids (VFAs) are not normally present. The second method (a 5-point titration procedure) was developed for anaerobic environments where VFAs may be encountered. Generally, fairly accurate and repetitive results (precision > 95...

  6. Ascorbic acid and pectin in different sizes and parts of citric fruits

    OpenAIRE

    Larissa Akemi Ywassaki; Solange Guidolin Canniatti-Brazaca

    2011-01-01

    Citric fruits - in natura, as frozen pulp or even as juice - are one of the most important Brazilian exportation products. They are a source of ascorbic acid - a potent antioxidant, and pectin, which is used in the food industry and is an important dietary fiber. This project aims to quantify ascorbic acid and pectin contents in citric fruits, commercial oranges and tangerines, comparing them in sizes and varieties. Ascorbic acid amount was measured in juice comparing sizes, varieties and sto...

  7. 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 <2 MPa) and modulus (from 93 to <10 MPa), increased water vapor permeability (WVP, from 3 to 9 g.mm.kPa(-1).h(-1).m(-2)), and decreased insoluble matter (IM, from 35% to 24%). Although a crosslinking effect by CA was not confirmed, it has been suggested to occur from its effects on films. CA noticeably increased IM (from <10% to almost 40%); moreover, when measured on a dry film basis, the CA effects presented a noticeable tendency to increases strength and modulus, and to decrease WVP. The red color density was decreased by CA, suggesting a destabilization of anthocyanins. PMID:26769510

  8. 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. PMID:26099461

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

    Science.gov (United States)

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

    2012-06-01

    This study involves the evaluation of the effect of certain stabilizers, that is, citric acid (CT), tartaric acid (TA) and boric acid (BA) on the degradation of ascorbic acid (AH(2) ) in oil-in-water cream formulations exposed to the UV light and stored in the dark. The apparent first-order rate constants (0.34-0.95 × 10(-3) min(-1) in light, 0.38-1.24 × 10(-2) day(-1) in dark) for the degradation reactions in the presence of the stabilizers have been determined. These rate constants have been used to derive the second-order rate constants (0.26-1.45 × 10(-2) M(-1) min(-1) in light, 3.75-8.50 × 10(-3) M(-1) day(-1) in dark) for the interaction of AH(2) and the individual stabilizers. These stabilizers are effective in causing the inhibition of the rate of degradation of AH(2) both in the light and in the dark. The inhibitory effect of the stabilizers is in the order of CT > TA > BA. The rate of degradation of AH(2) in the presence of these stabilizers in the light is about 120 times higher than that in the dark. This could be explained on the basis of the deactivation of AH(2) -excited triplet state by CT and TA and by the inhibition of AH(2) degradation through complex formation with BA. AH(2) leads to the formation of dehydroascorbic acid (A) by chemical and photooxidation in cream formulations. PMID:22296174

  10. Upgrading of citric acid production from cheap carbohydrate sources as affected by aspergillus

    International Nuclear Information System (INIS)

    Five strains of aspergillus niger (EMCC 102, EMCC 104, EMCC 111, EMCC 132 and EMCC 147) were for citric acid production at different incubation period using different cheap carbohydrate substrates, such as beet, cane and citrus molasses and milk whey. A. niger EMCC 111 was found to be the most potent strain for citric acid production from beet molasses after 11 days of incubation at 30 degree. The studies concerning molasses concentration and nitrogen sources (inorganic and organic sources with different concentration, revealed that 30 g% beet molasses and ammonium sulfate with 0.05 g% as N2 content, gave the highest production of citric acid. Gamma irradiated inocula of A. niger EMCC 111 at doses (0.05-0.8 KGy), showed that the dose 0.4 KGy was the optimum for maximum citric acid production. 8 tabs

  11. Kinetics Studies on citric acid production by gamma ray induced mutant of Aspergillus niger

    International Nuclear Information System (INIS)

    Effect of cultural pH and incubation temperature on citric acid yield and kinetic patterns of citric acid fermentation by a natural isolate of aspergillus niger as CA16 and one of its gamma ray induced mutants were studied using cane molasses as growth and fermentation substrate. Mutant strain, 277/30 gave maximum citric acid yield of 85 g/l at pH 3.5 and 28 degree centigrade in molasses medium adjusted to 16% sugar and 25% prescott salt in the medium. Parent strain, CA16 gave a maximum yield of 34 g/l at pH 4.0 and 26 degree centigrade in molasses medium adjusted to 16% sugar and 100% prescott salt in the medium. In kinetic studies, strains showed combination kinetics of citric acid fermentation where product formation is directly related to growth and cell mass and indirectly related to carbohydrate uptake

  12. The isolation and improvement of Aspergillus niger by radiation for higher production of citric acid

    International Nuclear Information System (INIS)

    Local citric acid producer of fungal strain Aspergillus niger have been successfully isolated from stale bread and onion. The isolates, designated as SB 1 and NN I showed a potential performance for citric acid production of 49% and 52% yield respectively, in shake flask studies. The strain improvement on NN1 was carried out by radiation induced mutation by gamma rays at LD50 of 1.28 kGy

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

    OpenAIRE

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

    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 maximu...

  14. 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. PMID:27054882

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

    International Nuclear Information System (INIS)

    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

  16. 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.

  17. Comparative analysis of acetic and citric acid on internal milieu of broiler chickens

    Directory of Open Access Journals (Sweden)

    Marcela Capcarova

    2014-02-01

    Full Text Available Normal 0 21 false false false CS JA X-NONE The aim of the present study was to analyse the effect of two organic acids (acetic and citric acid inclusion on serum parameters and the level of antioxidant status of broiler chickens. Some organic acidifiers reduce the growth of many intestinal bacteria, reduce intestinal colonisation and reduce infectious processes, decrease inflammatory processes at the intestinal mucosa, increase villus height and function of secretion, digestion and absorption of nutrients. Broiler chickens hybrid Ross 308 (n=180 were divided into 3 groups: one control (C and two experimental groups (E1, E2. Experimental animals received acetic and citric acid per os in water in single dose 0.25% for 42 days. After 42 days of feeding blood samples were collected (n=10 in each group. Significant decrease of serum triglycerides in citric acid group when compared with the control group was recorded. Acetic acid administration resulted in increased sodium level. Significant increase of albumin content in both experimental groups and increase of bilirubin content in citric group was recorded. Acids administration had no significant effect on other serum and antioxidant parameters. Acetic and citric acid had no harmful influenced on internal milieu of broiler chickens. The research on the field of organic acid will be worthy of further investigation.

  18. 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.

  19. 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

  20. 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%.

  1. 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.

  2. Process optimization of citric acid production from aspergillus niger using fuzzy logic design

    International Nuclear Information System (INIS)

    The inherent non-linearity of citric acid fermentation from Aspergillus niger renders its control difficult, so there is a need to fine-tune the bioreactor performance for maximum production of citric acid in batch culture. For this, fuzzy logic is becoming a popular tool to handle non-linearity of a batch process. The present manuscript deals with fuzzy logic control of citric acid accretion by A. niger in a stirred tank reactor using blackstrap sugarcane molasses as a basal fermentation medium. The customary batches were termed as control while those under fuzzy logic were experimental. The performance of fuzzy logic control of stirred tank reactor was found to be very encouraging for enhanced production of citric acid. The comparison of kinetic parameters showed improved citrate synthase ability of experimental culture (Yp/x = 7.042 g/g). When the culture grown on 150 g/l carbohydrates was monitored for Qp, Qs and Yp/s, there was significant enhancement in these variables over the control. Specific productivity of culture (qp = 0.070 g/g cells/h) was several fold increased. The enthalpy (HD = 70.5 kJ/mol) and entropy of activation (S = -144 J/mol/K) of enzyme for citric acid biosynthesis, free energies for transition state formation and substrate binding for sucrose hydrolysis of experimental were substantially improved. (author)

  3. Process optimization of citric acid production from aspergillus niger using fuzzy logic design

    International Nuclear Information System (INIS)

    The inherent non-linearity of citric acid fermentation from Aspergillus niger renders its control difficult, so there is a need to fine-tune the bioreactor performance for maximum production of citric acid in batch culture. For this, fuzzy logic is becoming a popular tool to handle non-linearity of a batch process. The present manuscript deals with fuzzy logic control of citric acid accretion by A. niger in a stirred tank reactor using blackstrap sugarcane molasses as a basal fermentation medium. The customary batches were termed as 'control' while those under fuzzy logic were 'experimental'. The performance of fuzzy logic control of stirred tank reactor was found to be very encouraging for enhanced production of citric acid. The comparison of kinetic parameters showed improved citrate synthase ability of experimental culture (Yp/x = 7.042 g/g). When the culture grown on 150 g/l carbohydrates was monitored for Qp, Qs and Yp/s, there was significant enhancement in these variables over the control. Specific productivity of culture (qp = 0.070 g/g cells/h) was several fold increased. The enthalpy (HD = 70.5 kJ/mol) and entropy of activation (S = -144 J/mol/K) of enzyme for citric acid biosynthesis, free energies for transition state formation and substrate binding for sucrose hydrolysis of experimental were substantially improved. (author)

  4. Column leaching of chromium and nickel from a contaminated soil using EDTA and citric acid

    International Nuclear Information System (INIS)

    This study investigates the column leaching of a soil contaminated mainly with Cr and Ni by using two chelants: citric acid (biodegradable) and EDTA (non-biodegradable) followed with water rinse. The chelants lead to Cr and Ni leaching, in addition to major elements (Ca, Fe, Mg, Al, Mn and Zn) showing the dissolution of soil mineral constituents. EDTA leaches more major elements and Ni than citric acid related to the respective stability of metal–chelant complexes; citric acid leaches more Cr than EDTA, certainly because of a substitution reaction with Cr(VI). In the case of alternating chelant/water applications, leaching occurs during the chelant applications, but also during water applications. In the case of chelant/water applications followed by continuous water application, both Cr and Ni leach over time. This increased mobility could be due to the residual chelant present in soil as well as to the dissolution/mobilization of mineral or organic soil fractions. - Highlights: ► Column leaching of an industrial soil contaminated with chromium and nickel. ► Citric acid or EDTA were used alternatively or followed with water rinse. ► Chelants lead to Cr and Ni leaching and the dissolution of soil mineral constituents. ► Leaching of these two metals proceeds continuously during water rinse. ► Chelants deeply impacted Cr and Ni mobility. - Citric acid or EDTA application deeply impact Cr and Ni mobility during column leaching of a contaminated soil.

  5. Citric acid mediated phyto extraction of cadmium by maize (zea mays l.)

    International Nuclear Information System (INIS)

    The aim of the investigation was to determine the potential of citric acid for accumulation and translocation of cadmium and their effect on maize growth. The plants were grown in small plastic glasses and treated with 300 mg kg/sup -1/ CdCl/sub 2/ and 0, 0.25, 0.5, 1 and 2 g kg/sup -1/ of citric acid. After 10 days, the plants were harvested, dried and root and shoot biomass weighed. To study the efficiency of maize to bioaccumulate metal, uptake of cadmium was studied in the root and shoot. The results showed that heavy metal accumulated more in roots than the shoots and application of citric acid depressed Cd uptake at all concentrations. Percent decrease in Cd uptake was 58, 35, 26, 25 and 63, 46, 44, 42 by Sahiwal-2002 and Pak-affgoee, respectively at 0.25, 0.5, 1 and 2 g kg/sup -1/ of citric acid application. Maize proved to be an effective accumulator for cadmium, however, neither concentration of citric acid showed advantages for phytoextraction of cadmium. (author)

  6. Influence of citric acid on the morphology and magnetic properties of barium ferrite thin films

    International Nuclear Information System (INIS)

    Hexagonal barium ferrite (BaFe12O19) thin films were fabricated by spin coating of precursors from sol-gel methods. Different amount of citric acid was added. Weight loss and changes of chemical bonds during the heat treatment below 500 deg. C were recorded by thermogravity analyzer and Fourier transform infrared spectroscopy, respectively. The morphology of the films, i.e. the amount of acicular crystallites in the film, was controlled by adjusting the quantity of citric acid. The X-ray diffraction shows that the films are c-axis oriented, but the crystallization is less perfect with the increase of the citric acid. With the increase of the citric acid, the percentage of the acicular crystallites increased. At the same time, the coercivity force increased. The acicular crystallites were not exchange-coupled to the platelet crystallites. The citric acid was understood to form complex with iron ions and accelerate the exothermal auto-combustion. The c-axis oriented growth of the film was thus deteriorated.

  7. Irradiated solutions of citric acid in the context of chemical evolution

    International Nuclear Information System (INIS)

    The radiolysis of citric acid in an aqueous solution and its connection with chemical evolution has been investigated. The importance of this compound which, probably had a double role during the evolutive period, first as a precursor in the synthesis of some pyrimidines and second as metabolic intermediary in the carboxilic acids cycle. The decomposition of the citric acid, the identification of the products obtained from the radiolysis and the distributions of these products were investigated with relation to the different doses used. (author) 9 refs.; 1 fig

  8. Aqueous dissolution behaviour of Nd-bearing zirconolite in citric acid at 90 deg C

    International Nuclear Information System (INIS)

    The capacity for zirconolite to incorporate actinides, combined with a very high chemical durability, makes zirconolite-rich ceramics potential candidates for the containment of minor actinides from reprocessing of nuclear spent fuel. Our studies examine the chemical durability of sintered Nd-bearing zirconolite under simulated geological repository conditions, demonstrating the effect of citric acid (at varying concentrations), as an organic complexing agent, on the leaching behaviour of zirconolite under a low flow regime. The complexation limit of zirconolite at pH=5 in citrate media appears to be reached by 0.001 M citric acid concentration. Secondary phase development (titania and possibly titania-rich hydrolyzed species) was evident on the zirconolite leached in 0.0001 M citric acid, similar to that on zirconolite leached in water. (authors)

  9. Hepatoprotective effects of citric acid and aspartame on carbon tetrachloride-induced hepatic damage in rats

    OpenAIRE

    Omar M. E. Abdel Salam; Shaffie, Nermeen M.; Sleem, Amany A.

    2009-01-01

    The aim of this study was to investigate the effect of citric acid or the sweetening agent aspartame on the CCl4-induced hepatic injury in rats. Citric acid (10 mg/kg, 100 mg/kg or 1000 mg/kg), aspartame (0.625 or 1.25 mg/kg) or silymarin (25 mg/kg) was given once daily orally simultaneously with CCl4 and for one week thereafter. The administration of citric acid at 100 mg/kg or 1000 mg/kg to CCl4-treated rats reduced elevated plasma ALT by 44.1-63.3 %, AST by 47.8-70.6 %, ALP by 41.7-67.2 %,...

  10. 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.

  11. 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.

  12. The influence of citric acid, EDTA, and fulvic acid on U(VI) sorption onto kaolinite

    Energy Technology Data Exchange (ETDEWEB)

    Barger, Michelle, E-mail: Michelle.l.barger@wmich.edu [Department of Geosciences, Western Michigan University, Kalamazoo, MI (United States); Koretsky, Carla M. [Department of Geosciences, Western Michigan University, Kalamazoo, MI (United States)

    2011-06-15

    Uranium(VI) sorption onto kaolinite was investigated as a function of pH (3-12), sorbate/sorbent ratio (1 x 10{sup -6}-1 x 10{sup -4} M U(VI) with 2 g/L kaolinite), ionic strength (0.001-0.1 M NaNO{sub 3}), and pCO{sub 2} (0-5%) in the presence or absence of 1 x 10{sup -2}-1 x 10{sup -4} M citric acid, 1 x 10{sup -2}-1 x 10{sup -4} M EDTA, and 10 or 20 mg/L fulvic acid. Control experiments without-solids, containing 1 x 10{sup -6}-1 x 10{sup -4} M U(VI) in 0.01 M NaNO{sub 3} were used to evaluate sorption to the container wall and precipitation of U phases as a function of pH. Control experiments demonstrate significant loss (up to 100%) of U from solution. Although some loss, particularly in 1 x 10{sup -5} and 1 x 10{sup -4} M U experiments, is expected due to precipitation of schoepite, adsorption on the container walls is significant, particularly in 1 x 10{sup -6} M U experiments. In the absence of ligands, U(VI) sorption on kaolinite increases from pH {approx}3 to 7 and decreases from pH {approx}7.5 to 12. Increasing ionic strength from 0.001 to 0.1 M produces only a slight decrease in U(VI) sorption at pH < 7, whereas 10% pCO{sub 2} greatly diminishes U(VI) sorption between pH {approx}5.5 and 11. Addition of fulvic acid produces a small increase in U(VI) sorption at pH < 5; in contrast, between pH 5 and 10 fulvic acid, citric acid, and EDTA all decrease U(VI) sorption. This suggests that fulvic acid enhances U(VI) sorption slightly via formation of ternary ligand bridges at low pH, whereas EDTA and citric acid do not form ternary surface complexes with the U(VI), and that all three ligands, as well as carbonate, form aqueous uranyl complexes that keep U(VI) in solution at higher pH.

  13. The influence of citric acid, EDTA, and fulvic acid on U(VI) sorption onto kaolinite

    International Nuclear Information System (INIS)

    Uranium(VI) sorption onto kaolinite was investigated as a function of pH (3-12), sorbate/sorbent ratio (1 x 10-6-1 x 10-4 M U(VI) with 2 g/L kaolinite), ionic strength (0.001-0.1 M NaNO3), and pCO2 (0-5%) in the presence or absence of 1 x 10-2-1 x 10-4 M citric acid, 1 x 10-2-1 x 10-4 M EDTA, and 10 or 20 mg/L fulvic acid. Control experiments without-solids, containing 1 x 10-6-1 x 10-4 M U(VI) in 0.01 M NaNO3 were used to evaluate sorption to the container wall and precipitation of U phases as a function of pH. Control experiments demonstrate significant loss (up to 100%) of U from solution. Although some loss, particularly in 1 x 10-5 and 1 x 10-4 M U experiments, is expected due to precipitation of schoepite, adsorption on the container walls is significant, particularly in 1 x 10-6 M U experiments. In the absence of ligands, U(VI) sorption on kaolinite increases from pH ∼3 to 7 and decreases from pH ∼7.5 to 12. Increasing ionic strength from 0.001 to 0.1 M produces only a slight decrease in U(VI) sorption at pH 2 greatly diminishes U(VI) sorption between pH ∼5.5 and 11. Addition of fulvic acid produces a small increase in U(VI) sorption at pH < 5; in contrast, between pH 5 and 10 fulvic acid, citric acid, and EDTA all decrease U(VI) sorption. This suggests that fulvic acid enhances U(VI) sorption slightly via formation of ternary ligand bridges at low pH, whereas EDTA and citric acid do not form ternary surface complexes with the U(VI), and that all three ligands, as well as carbonate, form aqueous uranyl complexes that keep U(VI) in solution at higher pH.

  14. Effect of Pre-Harvest Foliar Application of Citric Acid and Malic Acid on Chlorophyll Content and Post-Harvest Vase Life of Lilium cv. Brunello

    OpenAIRE

    Darandeh, Nafiseh; Hadavi, Ebrahim

    2012-01-01

    Citric acid is a regular ingredient in many vase solution formulations but pre-harvest use of citric acid is a novel method in vase life extension of cut flowers, which is reported on tuberose earlier. In order to verify previous result, and check for possible substitution of citric acid by malic acid, the current research was designed. Citric acid (0, 0.075, 0.15% w/v) and malic acid (0, 0.075, 0.15% w/v) were used in a factorial design with three replications. Foliar sprays were applied two...

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

    Directory of Open Access Journals (Sweden)

    Jinzhong Wan

    Full Text Available 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.

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

    Science.gov (United States)

    He, Fu-Yi; Kim, Hyun-Wook; Hwang, Ko-Eun; Song, Dong-Heon; Kim, Yong-Jae; Ham, Youn-Kyung; Kim, Si-Young; Yeo, In-Jun; Jung, Tae-Jun; Kim, Cheon-Jei

    2015-01-01

    The objective of this study was to examine the effect of ginger extract (GE) combined with citric acid on the tenderness of duck breast muscles. Total six marinades were prepared with the combination of citric acid (0 and 0.3 M citric acid) and GE (0, 15, and 30%). Each marinade was sprayed on the surface of duck breasts (15 mL/100 g), and the samples were marinated for 72 h at 4℃. The pH and proteolytic activity of marinades were determined. After 72 h of marination, Warner Bratzler shear force (WBSF), myofibrillar fragmentation index (MFI), pH, cooking loss, moisture content, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and protein solubility were evaluated. There was no significant (p>0.05) difference in moisture content or cooking loss among all samples. However, GE marination resulted in a significant (ptenderization effect of GE combined with citric acid may be attributed to various mechanisms such as increased MFI and myofibrillar protein solubility. PMID:26877631

  17. 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.

  18. 77 FR 6061 - Citric Acid and Certain Citrate Salts From Canada: Preliminary Results of Antidumping Duty...

    Science.gov (United States)

    2012-02-07

    ... and Countervailing Duty Administrative Reviews and Request for Revocation in Part, 76 FR 37781 (June... Duty Orders, 74 FR 25703 (May 29, 2009) (Citric Acid Duty Orders). \\2\\ Archer Daniels Midland Company... Rescind in Part, 70 FR 39735, 39737 (July 11, 2005), unchanged in Notice of Final Results and...

  19. Optimization of substrate concentration for enhanced citric acid production by aspergillus niger M-101

    International Nuclear Information System (INIS)

    Studying the effect of different sugar concentration of beet molasses on citric acid accumulation in batch fermentation, 150 g/litre sugar concentration was found to be optimal for maximum citric acid production (27.25+-2.35 g/litre) using Aspergillus niger M-101. Y/sup p/x/ value for product formation increased with increase in sugar concentration through out the study. Qp value for citric acid production also increased with increase in sugar concentration and reached the maximum (0.141 g/litre/h) at 150 g/litre sugar concentration but with further increase in sugar concentration, the value decreased. When culture was grown at different substrate concentrations, the kinetic parameters monitored for Y/sub x/s/, Y/sub p/s/ and Y/sub p/x/, Q/sub p/, Q/sub s/ and q/sub p/ showed significant enhancement (p <= 0.05) in citric acid production as well as biomass growth. (author)

  20. 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…

  1. Synthesis and characterisation of manganese oxides from potassium permanganate and citric acid mixtures

    Science.gov (United States)

    Burhanuddin, Syazwani; Yarmo, Ambar; Yamin, Bohari M.

    2013-11-01

    Reaction of KMnO4 and citric acid at different stoichiometric ratio found to give black precipitate after calcined at 500 %C. The black precipitate are classified as two type of manganese oxides mineral namely as bixbyite and hollandite. IR and XRD data were in agreement with the literature report.

  2. Hollow NiO nanofibers modified by citric acid and the performances as supercapacitor electrode

    International Nuclear Information System (INIS)

    Graphical abstract: The possible formation process of NiO nanofibers without citric acid (a), and modified by citric acid (b). When the nanofibers is modified by citric acid, the nickel citrate is produced by complexing action of citric acid and nickel nitrate. Because of the larger space steric hindrance, the structure is limited by the molecular geometry. Under high temperature, the hollow nanofibers composed of NiO slices formed after the removal of PVP. Highlights: ► The method of obtaining hollow nanofibers is raised for the first time. ► The prepared NiO nanofibers are hollow tube and comprised of many NiO sheets. ► The hollow structure facilitated the electrolyte penetration. ► The hollow NiO nanofibers have good electrochemical properties. -- Abstract: NiO nanofibers modified by citric acid (NiO/CA) for supercapacitor material have been fabricated by electrospinning process. The characterizations of the nanofibers are investigated by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Electrochemical properties are characterized by cyclic voltammetry, galvanostatic charge/discharge measurements, and electrochemical impedance spectroscopy. Results show that the NiO/CA nanofibers are hollow tube and comprised of many NiO sheets. Furthermore, the NiO/CA nanofibers have good electrochemical reversibility and display superior capacitive performance with large capacitance (336 F g−1), which is 2.5 times of NiO electrodes. Moreover, the NiO/CA nanofibers show excellent cyclic performance after 1000 cycles

  3. 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.

  4. 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.

  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. Contribution to the study of pertechnetate (sup(99m)Tc) stannous citrate - citric acid complexation

    International Nuclear Information System (INIS)

    Pertechnetate/citric acid/stannous citrate complexation carried out from a lyophilisate of stannous citrate in citric medium at pH5 leads to the formation of separable compounds. These compounds are tin-free technetium citrates. Similar results have been described in the case of complexation reactions with glycolic, thioglycolic and thiomalic acids and with other carboxylates such as dimercaptosuccinic acid. These processes include the reduction of Tcsup(VIII) by Snsup(II) in the presence of thiomalic acid under conditions similar to our own: stannous thiomalate in thiomalic medium to which is added the pertechnetate solution producing Tc-thiomalate complexes variable with the reaction pH. Also worth considering is the possible complexation between pertechnetate and the same acid in the absence of reducing ion, following a special procedure (heating). The complexes described here contain the oxotechnetium bond (terminal oxygen-technetium) and a strong probability exists in favour of dimerisation. Their stability, for a reaction in acid solution: pH 5.0/5.5, becomes satisfactory if: the solution is concentrated enough; bubbling by an inert gas is carried out; room temperature is not exceeded. The development takes place through a partial reoxidation characterised by colour change. An original interaction between reduced states of Tc and citric acid may be claimed with certainty under our experimental conditions. The difficulty then lies in the passage to the tracer stage when the isotope sup(99m)Tc is used

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

    OpenAIRE

    Farshad Darvishi; Iraj Nahvi; Hamid Zarkesh-Esfahani; Fariborz Momenbeik

    2009-01-01

    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 lip...

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

    OpenAIRE

    Francesco Ferella; Ida De Michelis; Francesca Beolchini; Valentina Innocenzi; Francesco Vegliò

    2010-01-01

    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 exp...

  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. Effect of Pre-Harvest Foliar Application of Citric Acid and Malic Acid on Chlorophyll Content and Post-Harvest Vase Life of Lilium cv. Brunello.

    Science.gov (United States)

    Darandeh, Nafiseh; Hadavi, Ebrahim

    2011-01-01

    Citric acid is a regular ingredient in many vase solution formulations but pre-harvest use of citric acid is a novel method in vase life extension of cut flowers, which is reported on tuberose earlier. In order to verify previous result, and check for possible substitution of citric acid by malic acid, the current research was designed. Citric acid (0, 0.075, 0.15% w/v) and malic acid (0, 0.075, 0.15% w/v) were used in a factorial design with three replications. Foliar sprays were applied two times during growth period of Lilium plants. The results point out that 0.15% citric acid alone had increased vase life from 11.8 in control treatment to 14 days (α < 0.05). The interesting finding was the effect of citric acid on bulbil weight, which was decreased from 9 g in control to 1.5 g in treatment containing combination of 0.075% citric acid and 0.075% malic acid. Malic acid while having no direct effect on pre-mentioned traits surprisingly increased the chlorophyll content significantly. The interaction effect between citric acid and malic acid on vase life and chlorophyll content proved significant and was evident in results, both as antagonistic and synergistic in various traits. PMID:22639626

  11. Quantitative Assessment of Citric Acid in Lemon Juice, Lime Juice, and Commercially-Available Fruit Juice Products

    Science.gov (United States)

    PENNISTON, KRISTINA L.; NAKADA, STEPHEN Y.; HOLMES, ROSS P.; ASSIMOS, DEAN G.

    2009-01-01

    Background and Purpose Knowledge of the citric acid content of beverages may be useful in nutrition therapy for calcium urolithiasis, especially among patients with hypocitraturia. Citrate is a naturally-occurring inhibitor of urinary crystallization; achieving therapeutic urinary citrate concentration is one clinical target in the medical management of calcium urolithiasis. When provided as fluids, beverages containing citric acid add to the total volume of urine, reducing its saturation of calcium and other crystals, and may enhance urinary citrate excretion. Information on the citric acid content of fruit juices and commercially-available formulations is not widely known. We evaluated the citric acid concentration of various fruit juices. Materials and Methods The citric acid content of 21 commercially-available juices and juice concentrates and the juice of three types of fruits was analyzed using ion chromatography. Results Lemon juice and lime juice are rich sources of citric acid, containing 1.44 and 1.38 g/oz, respectively. Lemon and lime juice concentrates contain 1.10 and 1.06 g/oz, respectively. The citric acid content of commercially available lemonade and other juice products varies widely, ranging from 0.03 to 0.22 g/oz. Conclusions Lemon and lime juice, both from the fresh fruit and from juice concentrates, provide more citric acid per liter than ready-to-consume grapefruit juice, ready-to-consume orange juice, and orange juice squeezed from the fruit. Ready-to-consume lemonade formulations and those requiring mixing with water contain ≤6 times the citric acid, on an ounce-for-ounce basis, of lemon and lime juice. PMID:18290732

  12. Effect of pre-harvest foliar application of citric acid and malic acid on chlorophyll content and post-harvest vase life of Lilium cv. Brunello

    Directory of Open Access Journals (Sweden)

    Nafiseh eDarandeh

    2012-01-01

    Full Text Available Preharvest use of citric acid is a novel method in vase life extension of cut flowers, which is reported on tuberose earlier and confirmed here on lilium. In this research citric acid (0, 0.075, 0.15 percent v/v and malic acid (0, 0.075, 0.15 percent v/v were used together two times during growth period of lilium plants in a randomized factorial design with three replications. The results point out that 0.15% citric acid had increased vase life from 13.1 to 14 days (α=0.05. The interesting finding was the effect of citric acid on bulbil weight, which was decreased from 8.6 gr to 2.9 gr in 0.15% citric acid per cut flower. Malic acid while having no effect on pre-mentioned traits surprisingly increased the chlorophyll content significantly. The interaction effect between citric acid and malic acid on vase life and chlorophyll content proved significant and was evident in results both as antagonistic and synergistic in various traits. In mean comparison of factor-levels, the effect of citric acid on vase-life extension was more prominent increasing it from 11.8 to 14.3 days in treatment with 0.15% citric acid and without malic acid compared to control treatment.

  13. Semi-pilot scale production of citric acid in cane molasses by gamma-ray induced mutants of Aspergillus niger

    International Nuclear Information System (INIS)

    Utilizing cane molasses as substrate, semi-pilot scale production of citric acid was investigated in fermentation trays (40 x 35 cm) with several gamma-ray induced mutants of Aspergillus niger. Of the mutants tested, two were found to have high yield efficiency (14/20, 51.06%; 79/20, 50.35%) of sugar to citric acid. The yield of other mutants (HB3, 10/20, 164/20, 277/30 and 112/40) ranged between 30 to 42%. The prospect of utilizing the high yielding mutants for commercial production of citric acid has been discussed. (author)

  14. 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.

  15. 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.

  16. 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.

  17. Breeding of citric acid-producing bacteria by 15 keV N+ ion implantation

    International Nuclear Information System (INIS)

    Aspergillus niger strains CK1-16, the bacteria commonly used in industrial production of citric acid, were implanted with 3.10 x 1014 to 2.58 x 1015 ions/cm2 of 15 keV N+ ions. Survival rate of the bacteria at different doses was investigated, and mutagenic effects of the microbe were studied. From the ion-implanted specimens, authors were able to obtain three mutant strains that produce increased yield of citric acid. The 71 hours yield of Mutant Strain 4 hash-8-1 incubated in cassava and corn flour media is 14% higher than the CK1-16 strain, while Mutant Strains 4hash-8-7and 4hash-8-7, incubated in corn flour media are 15.9% and 17.0% higher than the CK1-16 strain, respectively. The results also show that the mutant strains have high genetic stability. (authors)

  18. 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

  19. Effects of citric acid ratio on nanosized crystalline CaMnO3 powder

    International Nuclear Information System (INIS)

    Molar concentration ratios of citric acid to Ca2+ affect properties of CaMnO3 powders. In this paper, CaMnO3 gel was prepared through the sol-gel method with deionized water and ethylene glycol as solvent, different ratios of citric acid as chelate, and metal nitrates as starting materials. Perovskite polycrystalline CaMnO3 powders were prepared via calcining the dry gel, and were analyzed with XRD, SEM and Marlvern granularity analyzer. The results show that the crystal size ranges from 20 to 50 nm, and the resulting perovskite CaMnO3 powders are flat-shaped granules of about 300-500 nm. The granularity and crystal size of the CaMnO3 powders increase slightly with the increase of the molar concentration ratio. (authors)

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

    OpenAIRE

    Camilo A. Navarro D.; Cesar A. Sierra; Cristian Ochoa-Puentes

    2013-01-01

    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 crystal...

  1. Application of kaolin to improve citric acid production by a thermophilic Aspergillus niger.

    Science.gov (United States)

    Ali, Sikander

    2006-12-01

    Citric acid production by a thermophilic strain of the filamentous fungus Aspergillus niger IIB-6 in a medium containing blackstrap cane molasses was improved by the addition of kaolin to the fermentation medium. The fermentation was run in a 7.5-l stirred bioreactor (60% working volume). The optimal sugar concentration was found to be 150 g/l. Kaolin (1.0 ml) was added to the fermentation medium to enhance volumetric production. The best results in terms of product formation were observed when 15 parts per million (ppm) kaolin was added 24 h after inoculation. With added kaolin, citric acid production was enhanced 2.34-fold, compared to a control fermentation without added kaolin. The length of incubation to attain this product yield was shortened from 168 to 96 h. The comparison of kinetic parameters showed improved citrate synthase activity of the culture (Y (p/x)=7.046 g/g). When the culture grown at various kaolin concentrations was monitored for Q (p), Q (s), and q (p), there was significant improvement in these variables over the control. Specific production by the culture (q (p)=0.073 g/g cells/h) was improved several fold. The addition of kaolin substantially improved the enthalpy (DeltaH (D)=74.5 kJ/mol) and entropy of activation (DeltaS=-174 J/mol/K) for citric acid production, free energies for transition state formation, and substrate binding for sucrose hydrolysis. The performance of fuzzy logic control of the bioreactor was found to be very promising for an improvement ( approximately 4.2-fold) in the production of citric acid (96.88 g/l), which is of value in commercial applications. PMID:16871375

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

    OpenAIRE

    Demelash Jado; Khalid Siraj; Nathan Meka

    2014-01-01

    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 ...

  3. improving citric acid production from some carbohydrates by-products using irradiated aspergillus niger

    International Nuclear Information System (INIS)

    Twenty strains of A. niger were isolated from different sources, screened for their capacity to produce citric acid. All the isolated strains were able to produce citric acid in different quantities at different time intervals i.e. 4, 8 and 12 days on indicator medium. The best incubation period for production for all isolates was 12 days. The most potent strains for production were A1, A4 and A5, while A8, A16, A18 and A19 recorded weak production on that medium. Citric acid productivity were obtained by all strains when using different concentrations of four carbohydrate by-products (maize straw, potato peel wastes, sugar beet pulp and molasses) when each used alone without any additions after 12 days incubation and the production enhanced when the fermentation medium amended with the same concentrations of the mentioned substrates. Type and concentration of carbohydrate by-product affect the production of citric acid by A. niger strains under the study. Increasing substrate concentration led to increase in production, the best concentration for production was 25% for all carbohydrate by-products. As recorded with indicator medium, A1, A4 and A5 are also the most potent strains for production when growing on the four carbohydrate by-products supplemented to the basal medium, while A8, A6, A18 and A19 recorded the weak production with the carbohydrate by-products used.production of the parental isolates A1, A4 and A5 on indicator medium were: 0.96, 0.95 and 0.99 (mg/ml) respectively after 12 days incubation, while maximum production by the obtaining resulting isolates (Treated by UV irradiation) were: 1.78, 1.70 and 1.73 (mg/ml) from A4T2 (5 min.), A4T1 (10 min.) and A1T1 (5 min.), respectively.

  4. 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

  5. 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.

  6. Comparison of willow and sunflower for uranium phytoextraction induced by citric acid

    International Nuclear Information System (INIS)

    This study deals with an efficiency of a low dose of citric acid soil application on phytoextraction of uranium. Willow (Salix spp.) and sunflower (Helianthus annus L.) were tested in this experiment with contaminated soil. The enhancing of uranium bioaccumulation was confirmed, but in contrast to previous studies, the highest quantity of uranium was accumulated in leaves. After 5 weeks of citric acid treatment, willow was more efficient in the uptake and translocation of uranium than sunflower. The transfer coefficient calculated for leaves increased from 0.033 (control) to 0.74, or 0.56 after five doses of 5 mmol of citric acid per 1 kg of soil for willow or sunflower, respectively. The uptake characterized by the total U content achieved 88 and 108 mg kg-1 in relation to the above ground parts of sunflower and willow, respectively. Even though both plants accumulated U in their above ground parts in significant rate, they employed diverse ways to achieve it. At the end of the treatment, the physiological condition of the plants enabled us to continue this method. (author)

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

    OpenAIRE

    Alewo Opuada AMEH; Muhammed Tijani ISA; David ABUTU; Alibaba DANLAMI

    2014-01-01

    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...

  8. 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.

  9. 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.

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

    International Nuclear Information System (INIS)

    Highlights: → CAIW is very effective in desorbing cadmium from soil particle surfaces at soil mixture pHs of lower than 5. → The cadmium desorption efficiency of CAIW also depends on the initial sorbed concentration of cadmium on soil particle surfaces. → 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. → 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.

  11. 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.

  12. Effects of sodium metabisulphite and citric acid on the shelf life of fresh cut sweet potatoes

    Energy Technology Data Exchange (ETDEWEB)

    Sgroppo, S. C.; Vergara, L. E.; Tenev, M. D.

    2010-07-01

    Minimally processed vegetables are products susceptible to chemical and biological changes, thus becoming highly perishable. During sweet potatoes (Ipomoea batatas Lam.) processing, some deteriorative reactions occur affecting quality, mainly change of color. The purpose of this research is to avoid or minimize this deterioration, so the effects of application of chemical agents to fresh cut and refrigerated stored sweet potatoes were studied, evaluating the occurrence of major organoleptic, physicochemical and nutritional changes and assessing the sensory acceptability. Tests were done with sweet potato variety Colorada Correntina, which were treated with sodium metabisulphite/citric acid (pH = 2.91), arranged in polystyrene trays film, coated with PVC, and stored at 5 degree centigrade and 10 degree centigrade. Variations on the titratable acidity, pH, total sugars and ascorbic acid were registered and the surface color was evaluated through digital image analysis. The final product acceptability was determined through sensory evaluation and microbiological counts carried out at the beginning and at the end of the assays. During storage, there were slight changes in physicochemical characteristics such as absorbic acid and sugar content and in surface color as well. The microbial counts were lower than the fixed levels established by the Spanish legislature. The sensory attributes were rated as acceptable by consumers. Finally it is possible to assert that sweet potato Colorada Correntina minimally processed and treated with sodium metabisulphite 2%/citric acid can be preserved, packaged and stored at 5 degree centigrade for 14 days. (Author) 34 refs.

  13. Effects of chitosan and citric acid on pericarp browning and polyphenol oxidase activity of longan fruit

    Directory of Open Access Journals (Sweden)

    Wittaya Apai

    2010-01-01

    Full Text Available This research was designed to study the effects of chitosan and citric acid (CA on pericarp browning and polyphenol oxidase (PPO activity of longan fruit. The experiment was conducted by dipping longan fruit in 1.2% (w/v chitosan coating solution containing 1.0% CA (pH 3.3 for 2 min, in 1.0% CA solution (pH 2.6 for 2 min, and in distilled water for 2 min as a control. The treated fruits in each treatment were then packaged in a foam tray, wrapped with 11 μm PVC film and stored at 5°C, 95% RH for 27 days. Pericarp browning, pericarp color, pericarp pH, titratable acidity (TA, weight loss, polyphenol oxidase (PPO activity, and total phenol were monitored during storage. The results revealed that interaction betweenchitosan and CA demonstrated the best treatment in postponement of pericarp browning, which was indicated by the lowest browning index and high L* value, chroma, and hue angle. Based on browning index, the fruits treated with citric acid alone and the control fruits were not acceptable after 20 days, which those treated with both CA and chitosan were still acceptable after 27 days of storage. TA had a correlation with the pericarp pH and browning index. Chitosan mixed with citric acid exhibited a higher efficacy in preventing TA degradation in pericarp and maintaining low pericarp pH, compared to 1.0% CA treatment. In addition, low PPO activity and high total phenol content were found when CA was applied in combination withchitosan during storage.

  14. Effect of pre-harvest foliar application of citric acid and malic acid on chlorophyll content and post-harvest vase life of Lilium cv. Brunello

    OpenAIRE

    Nafiseh eDarandeh; Ebrahim eHadavi

    2012-01-01

    Preharvest use of citric acid is a novel method in vase life extension of cut flowers, which is reported on tuberose earlier and confirmed here on lilium. In this research citric acid (0, 0.075, 0.15 percent v/v) and malic acid (0, 0.075, 0.15 percent v/v) were used together two times during growth period of lilium plants in a randomized factorial design with three replications. The results point out that 0.15% citric acid had increased vase life from 13.1 to 14 days (α=0.05). The interesting...

  15. Ascorbic acid and pectin in different sizes and parts of citric fruits

    Directory of Open Access Journals (Sweden)

    Larissa Akemi Ywassaki

    2011-06-01

    Full Text Available Citric fruits - in natura, as frozen pulp or even as juice - are one of the most important Brazilian exportation products. They are a source of ascorbic acid - a potent antioxidant, and pectin, which is used in the food industry and is an important dietary fiber. This project aims to quantify ascorbic acid and pectin contents in citric fruits, commercial oranges and tangerines, comparing them in sizes and varieties. Ascorbic acid amount was measured in juice comparing sizes, varieties and storage conditions, using a tritimetric method with 2.6-dichlorobenzenoindophenol indicator. Total and soluble pectin in each part of the fruits (peel, albedo, pulp and juice were quantified using the polygalacturonic acid as a standard. Differences were found between the sizes. The highest content of vitamin C was found in the oranges (Bahia variety. Comparing the storage temperatures, the biggest loss was at room temperature. Albedo presented the highest content of pectin in all fruits. In juice, the total and soluble pectin contents increased as fruits size decreased. Oranges and tangerines differed in the amount of pectin

  16. 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.

  17. Effects of chitosan and citric acid on pericarp browning and polyphenol oxidase activity of longan fruit

    OpenAIRE

    Wittaya Apai; Vicha Sardsud; Pichaya Boonprasom; Uraporn Sardsud

    2010-01-01

    This research was designed to study the effects of chitosan and citric acid (CA) on pericarp browning and polyphenol oxidase (PPO) activity of longan fruit. The experiment was conducted by dipping longan fruit in 1.2% (w/v) chitosan coating solution containing 1.0% CA (pH 3.3) for 2 min, in 1.0% CA solution (pH 2.6) for 2 min, and in distilled water for 2 min as a control. The treated fruits in each treatment were then packaged in a foam tray, wrapped with 11 μm PVC film and stored at 5°C, 95...

  18. Periodontal healing following guided tissue regeneration with citric acid and fibronectin application.

    Science.gov (United States)

    Caffesse, R G; Nasjleti, C E; Anderson, G B; Lopatin, D E; Smith, B A; Morrison, E C

    1991-01-01

    This study was undertaken to determine the effects of guided tissue regeneration (GTR) with and without citric acid conditioning and autologous fibronectin application. The study subjects were four female beagle dogs with spontaneous periodontitis. The dogs were given thorough root debridement and 4 weeks later, mucoperiosteal flaps were raised on both sides of the mandible involving the 2nd, 3rd, and 4th premolar and 1st molar teeth. After debridement, notches were placed on the roots at the level of supporting bone. Citric acid (pH 1) was topically applied for 3 minutes on the exposed root surfaces of one side (experimental). The roots were irrigated with normal saline solution. Both the root surfaces and the inner surface of the flap were then bathed in autologous fibronectin in saline. Following this, Gore-Tex periodontal material was adapted to the roots of each tooth and sutured. The contralateral side, serving as control, was treated by surgery and application of Gore-Tex periodontal material only. All membranes were removed 1 month after surgery, and the dogs sacrificed at 3 months. Both mesio-distal and bucco-lingual microscopic histological sections were evaluated by descriptive histology, and linear measurements and surface area determination of the furcal tissues were made. Periodontal healing following the use of GTR procedure resulted in an increase in connective tissue and alveolar bone regeneration. Adjunctive critic acid plus autologous fibronectin produced slightly better results, but these differences were not statistically significant for this sample. PMID:2002428

  19. BIOSORPTION OF METHYLENE BLUE ON CHEMICALLY MODIFIED CHAETOPHORA ELEGANS ALGA BY HCl AND CITRIC ACID

    International Nuclear Information System (INIS)

    Chemical modification of Chaetophora Elegans algae with HCl and citric acid was undertaken in order to improve the methylene blue adsorption. The modified algae with 1 M HCl showed an increase in the maximum uptake from 143 mg g-1 to 320 mg g-1 due to elimination of carbonate. The modified algae with 1M citric acid showed an important decrease in the uptake from 143 mg g-1 to 20 mg g-1 due to increase in the cross linking degree. Acid concentration used in the chemical modification (0.1 M -1 M) is the major parameter affecting the maximum uptake. The temperature of the chemical modifica- tion has a small effect on the uptake. Langmuir-Freundlich isotherm model fitted better the isotherm adsorption data for all samples studied. Pseudo second order model was well in line with the experimental data. The adsorption rate constant (K ) is higher for modified algae with HCl than that of raw algae. The activation thermodynamic parameters E-a , ΔH, ΔS and ΔG were calculated. The maximum uptake is independent of isotherm adsorption temperature in the range studied. (author)

  20. Ascorbic acid and citric flavonoids for broilers under heat stress: effects on performance and meat quality

    Directory of Open Access Journals (Sweden)

    JEM Peña

    2008-06-01

    Full Text Available The aim of this study was to evaluate the effects of increasing doses of ascorbic acid (AA and citric flavonoids (quercetin and rutin on the performance and meat quality characteristics of broilers submitted to cyclic heat stress. Four-hundred one-day-old female Ross 308 were housed in 40 battery cages a in temperature controlled room. Treatments consisted of 0, 250, 500, and 1000 g/ton on of AA + citric flavonoids. Birds were fed ad libitum until 32 day of age. Beginning on day 14 post-hatch until the end of the experiment, in order to simulate cyclic heat stress, the temperature inside the room was increased to 32°C for 5 hours, and decreased until reaching the comfort temperature corresponding to the age of the animals. Birds were slaughtered at 33 days of age, and carcass and commercial cuts yields were determined. Thighs and boneless breast samples were collected and frozen for subsequent analyses of pH, cooking loss, shear force, color, and Thiobarbituric Acid Reactive Substances (TBARS. Significant differences (p <0.05 were found for feed efficiency from 1 to 7 days of age, with the best values for the birds fed 0 and 250 g/ton on of AA + citric flavonoids. At the end of the experiment, there were no differences in other performance variables, carcass and parts yields, pH, shear force, color and TBARS. The meat of the birds supplemented with 250 g/ton on of product presented the lowest cooking loss.

  1. Development of Better-Quality Assay Method for the Citric Acid and Sodium Citrate in Ophthalmic/Oral Solutions and Their Application to Deformulation Studies

    OpenAIRE

    Kishore Kumar Hotha; Tejashkumar Patel; Swapan Roychowdhury; Veerappan Subramanian

    2014-01-01

    There were several techniques determined for the analysis of citrate and citric acid mixtures in the pharmaceutical dosage forms. Titration methods, photometric and ion chromatographic methods were used for their determination. These methods will restrict too many factors where the accurate quantification of citrate and citric acid is extremely challenging. Citric acid is the natural flavor used as a preservative for many pharmaceutical applications. Deformulation techniques used for the manu...

  2. 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.

  3. 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.

  4. Degradation and in Vitro Biocompatibility studies of Citric acid based polyesters

    Directory of Open Access Journals (Sweden)

    J. Margaret Marie

    2014-09-01

    Full Text Available The suitability of a polymer for a particular application is dependent on its physical and chemical properties. The monomers used play a significant role in the synthesis of polymers for biomedical applications. In the present work two copolyesters, poly (1,12-dodecanediol citrate-co-1,12- dodecanediol sebacate (PP1; poly (1,12-dodecanediol citrate-co-1,12- dodecanediol itaconate (PP2 were synthesized by catalyst-free melt polyesterification using monomers - citric acid, sebacic acid, itaconic acid and 1,12-dodecanediol. The polymers exhibited mechanical and thermal properties that made them suitable candidates for degradation and biocompatibility studies. In the present work the degradation and in vitro biocompatibility studies were carried out. The degradation and biocompatibility data support the potential use of the elastomers in tissue engineering applications as well as other clinical procedures that may require a biodegradable elastomeric implant.

  5. 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.

  6. 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. PMID:27102367

  7. Recovery of cobalt and lithium from spent lithium ion batteries using organic citric acid as leachant

    International Nuclear Information System (INIS)

    In this work, a hydrometallurgical process based on leaching is applied to recover cobalt and lithium from spent lithium ion batteries (LIBs). Citric acid and hydrogen peroxide are introduced as leaching reagents and the leaching of cobalt and lithium with a solution containing C6H8O7.H2O is investigated. When both C6H8O7.H2O and H2O2 are used an effective recovery of Li and Co as their respective citrates is possible. The leachate is characterized by scanning electron micrography (SEM) and X-ray diffraction (XRD). The proposed procedure includes the mechanical separation of metal-containing particles and a chemical leaching process. Conditions for achieving a recovery of more than 90% Co and nearly 100% Li are achieved experimentally by varying the concentrations of leachant, time and temperature of the reaction as well as the starting solid-to-liquid ratio. Leaching with 1.25 M citric acid, 1.0 vol.% hydrogen peroxide and a S:L of 20 g L-1 with agitation at 300 rpm in a batch extractor results in a highly efficient recovery of the metals within 30 min of the processing time at 90 deg. C. This hydrometallurgical process is found to be simple, environmentally friendly and adequate for the recovery of valuable metals from spent LIBs.

  8. 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.

  9. 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)

  10. 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. PMID:22962799

  11. 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.

  12. Effect of forced aeration on citric acid production by Aspergillus sp. mutants in SSF.

    Science.gov (United States)

    Rodrigues, Cristine; Vandenberghe, Luciana P S; Sturm, Wilerson; Dergint, Dario E A; Spier, Michele Rigon; de Carvalho, Júlio Cesar; Soccol, Carlos R

    2013-12-01

    Citric acid (CA) is one of the most important products of fermentation in the world. A great variety of agro-industrial residues can be used in solid state fermentation. Aspergillus niger parental strain (CCT 7716) and two strains obtained by mutagenesis (CCT 7717 and CCT 7718) were evaluated in Erlenmeyer flasks and glass columns using citric pulp (CP) as substrate/support, sugarcane molasses and methanol. Best results using glass columns (forced aeration) were found in the fourth day of fermentation: 278.4, 294.9 and 261.1 g CA/kg of dry CP with CCT 7716, CCT 7718 and CCT 7717, respectively. In Erlenmeyer flasks (aeration by diffusion) CA reached 410.7, 446.8 and 492.7 g CA/kg of dry CP with CCT 7716, CCT 7718 and CCT 7717, respectively. The aeration by diffusion improved CA production by the three strains. A data acquisition system specially developed for biotechnological processes analysis was used to perform the respirometric parameters measurement. PMID:23760557

  13. 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.

  14. 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.

  15. [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. PMID:27011985

  16. 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. PMID:26572335

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

    Science.gov (United States)

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

    2016-11-01

    Poly (citric acid)-grafted-MWCNT (PCA-g-MWCNT) was incorporated as nanofiller in polyethersulfone (PES) to produce hemodialysis mixed matrix membrane (MMM). Citric acid monohydrate was polymerized onto the surface of MWCNTs by polycondensation. Neat PES membrane and PES/MWCNTs MMMs were fabricated by dry-wet spinning technique. The membranes were characterized in terms of morphology, pure water flux (PWF) and bovine serum albumin (BSA) protein rejection. The grafting yield of PCA onto MWCNTs was calculated as 149.2%. The decrease of contact angle from 77.56° to 56.06° for PES/PCA-g-MWCNTs membrane indicated the increase in surface hydrophilicity, which rendered positive impacts on the PWF and BSA rejection of the membrane. The PWF increased from 15.8Lm(-2)h(-1) to 95.36Lm(-2)h(-1) upon the incorporation of PCA-g-MWCNTs due to the attachment of abundant hydrophilic groups that present on the MWCNTs, which have improved the affinity of membrane towards the water molecules. For protein rejection, the PES/PCA-g-MWCNTs MMM rejected 95.2% of BSA whereas neat PES membrane demonstrated protein rejection of 90.2%. Compared to commercial PES hemodialysis membrane, the PES/PCA-g-MWCNTs MMMs showed less flux decline behavior and better PWF recovery ratio, suggesting that the membrane antifouling performance was improved. The incorporation of PCA-g-MWCNTs enhanced the separation features and antifouling capabilities of the PES membrane for hemodialysis application. PMID:27524052

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

    Science.gov (United States)

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

    2015-04-14

    Salivary α-amylase (sAA) is responsible for the 'pre-digestion' of starch in the oral cavity and accounts for up to 50 % of salivary protein in human saliva. An accumulating body of literature suggests that sAA is of nutritional importance; however, it is still not clear how sAA is related to individual's nutritional status. Although copy number variations (CNV) of the salivary amylase gene (AMY1) are associated with variation in sAA levels, a significant amount of sAA variation is not explained by AMY1 CNV. To measure sAA responses to gustatory stimulation with citric acid, we used sAA ratio (the ratio of stimulated sAA levels to those of resting sAA) and investigated acute sAA responses to citric acid in children with normal (Normal-BMI, n 22) and low (Low-BMI, n 21) BMI. The AMY1 gene copy number was determined by quantitative PCR. We, for the first time, demonstrated attenuated acute sAA responses (decreased sAA ratio) to gustatory stimulation in Low-BMI (thinness grade 3) children compared with the Normal-BMI children, which suggest that sAA responses to gustatory stimulation may be of nutritional importance. However, child's nutritional status was not directly related to their resting or stimulated sAA levels, and it was not associated with AMY1 gene copy number. Finally, AMY1 CNV might influence, but did not eventually determine, sAA levels in children. PMID:25784372

  19. 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.

  20. Bio-synthesis of citric acid from single and co-culture-based fermentation technology using agro-wastes

    Directory of Open Access Journals (Sweden)

    Sohaib Rafaqat Ali

    2016-01-01

    Full Text Available Agro-based materials are primarily composed of complex polysaccharides that strengthen microbial growth for the production of industrially relevant value-added products. Therefore, in the present study, solid state fermentation (SSF was carried out using agro-based waste materials (apple pomace, peanut shell and a mixture of both apple pomace and peanut shell with 50:50 ratio as carriers/support for SSF to enhance citric acid production from single and co-culture consortia of Aspergillus ornatus and Alternaria alternata. During initial screening trial it was observed that growth media supplemented with apple pomace under SSF process of co-culture consortia presenting the preeminent 0.46 ± 0.42 mg/mL of citric acid. On partial optimization co-culture showed the maximum citric acid yield (2.644 ± 0.99 mg/mL in the presence of arginine as a nutritional ingredient at 30 °C in an apple pomace based medium at 50% moisture content with pH of 5 and substrate concentration (25 g after 48th of solid state fermentation. In conclusion, a suitable addition of fermentative substrate to the SSF medium increased fungal growth, sugar utilization and citric acid production when used in lower concentrations.

  1. Quantitative analysis of citric acid/sodium hypophosphite modified cotton by HPLC and conductometric titration.

    Science.gov (United States)

    Ye, Tao; Wang, Bijia; Liu, Jian; Chen, Jiangang; Yang, Yiqi

    2015-05-01

    Isocratic HPLC was used in conjunction with conductometric titration to quantitatively examine the modification of cotton cellulose by citric acid (CA)/sodium hypophosphite (SHP). CA/SHP had been extensively used as a green crosslinking agent for enhancement of cellulose and other carbohydrate polymers without in-depth understanding of the mechanisms. The current study investigated all identifiable secondary polycarboxylic acids from CA decomposition in the CA/SHP-cellulose system under various curing conditions. It was found that CA decomposition was more sensitive to temperature compared with the desirable esterification reaction. Two crosslinking mechanisms, namely ester crosslinking and SHP crosslinking were responsible for the observed improvement in crease resistance of CA/SHP treated cotton fabrics. An oligomer of citraconic acid (CCA) and/or itaconic acid (IA) was identified as a possible contributor to fabric yellowing. Finally, the crease resistance of fabrics correlated strongly with CA preservation in polyol-added CA/SHP crosslinking systems. The dosage of polyol should be held below an inflexion point to keep the undesirable competition against cellulose minimum. The combination of HPLC and conductometric titration was demonstrated to be useful in studying the CA/SHP-cellulose crosslinking system. The findings have implications for better application of CA/SHP in polysaccharide modifications in general. PMID:25659676

  2. 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. PMID:26837219

  3. 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

  4. Whiteness improvement of citric acid crosslinked cotton fabrics: H2O2 bleaching under alkaline condition.

    Science.gov (United States)

    Tang, Peixin; Ji, Bolin; Sun, Gang

    2016-08-20

    Polycarboxylic acids have been employed as formaldehyde-free crosslinking agents in anti-wrinkle treatment for cotton fabrics. Cotton fabrics treated by citric acid (CA) catalyzed with effective catalysts have shown satisfactory anti-wrinkle properties. Meanwhile, CA is a natural-based and environmental friendly compound. However, the yellowing of CA treated fabrics is a stumbling block for its practical application. Due to the fact that CA firstly forms aconitic acid (AA) before forming anhydrides, the cause of the yellowing, hydrogen peroxide (H2O2) bleaching was adopted to treat the CA treated fabrics in order to break the CC bond structure and reduce the yellow color but retaining the desired anti-wrinkle properties. Thermogravimetric analysis and Fourier transformed infrared spectroscopy were employed to investigate the reactions. The results revealed that the H2O2 bleaching can effectively improve the whiteness and also maintain a good anti-wrinkle performance of the CA treated fabrics under an appropriate bleaching temperature and time. PMID:27178918

  5. Effect of pioglitazone, quercetin and hydroxy citric acid on extracellular matrix components in experimentally induced non-alcoholic steatohepatitis

    Directory of Open Access Journals (Sweden)

    Surapaneni Krishna Mohan

    2015-08-01

    Results:The experimental NASH rats treated with pioglitazone showed significant decrease in the levels of hyaluronic acid and significant increase in adiponectin levels when compared to experimentally induced NASH group, but did not show any effect on the levels of leptin. Contrary to these two drugs, viz. pioglitazone and hydroxy citric acid, the group treated with quercetin showedsignificant decrease in the levels of hyaluronic acid and leptin and significant decrease in adiponectin levels compared with that of experimentally induced NASH NASH group, offering maximum protection against NASH. Conclusion: Considering our findings, it could be concluded that quercetin may offer maximum protection against NASH by significantly increasing the levels of adiponectin, when compared to pioglitazone and hydroxy citric acid.

  6. Effect of antimony(III) on carbon steel corrosion inhibition by molybdate in citric acid solution

    International Nuclear Information System (INIS)

    Molybdate is known as a good corrosion inhibitor of carbon steel (CS). But it cannot inhibit CS corrosion in citric acid solution at 85 °C. It has been observed that the presence of small concentration of Sb(III) along with MoO42- inhibits CS corrosion efficiently. The corrosion inhibition by MoO42- have been studied extensively by varying the concentration of Sb(III) and MoO42-. A critical concentration of MoO42- is required to passivate CS in acid medium in the presence of Sb(III). The study shows that molybdate forms a thin protective layer on CS surface in presence of Sb(III) which provides the corrosion inhibition. Inhibition property and the layer composition on CS surface have been studied by electrochemical and surface analytical techniques. The protective layer is found to be composed of both Mo and Sb and appears to be formed due to cathodic reduction of Mo6+ to Mo5+ and Mo4+ and anodic oxidation of Fe and Sb. (author)

  7. Crystal structures of carbamate kinase from Giardia lamblia bound with citric acid and AMP-PNP.

    Directory of Open Access Journals (Sweden)

    Kap Lim

    Full Text Available The parasite Giardia lamblia utilizes the L-arginine dihydrolase pathway to generate ATP from L-arginine. Carbamate kinase (CK catalyzes the last step in this pathway, converting ADP and carbamoyl phosphate to ATP and ammonium carbamate. Because the L-arginine pathway is essential for G. lamblia survival and absent in high eukaryotes including humans, the enzyme is a potential target for drug development. We have determined two crystal structures of G. lamblia CK (glCK with bound ligands. One structure, in complex with a nonhydrolyzable ATP analog, adenosine 5'-adenylyl-β,γ-imidodiphosphate (AMP-PNP, was determined at 2.6 Å resolution. The second structure, in complex with citric acid bound in the postulated carbamoyl phosphate binding site, was determined in two slightly different states at 2.1 and 2.4 Å resolution. These structures reveal conformational flexibility of an auxiliary domain (amino acid residues 123-170, which exhibits open or closed conformations or structural disorder, depending on the bound ligand. The structures also reveal a smaller conformational change in a region associated the AMP-PNP adenine binding site. The protein residues involved in binding, together with a model of the transition state, suggest that catalysis follows an in-line, predominantly dissociative, phosphotransfer reaction mechanism, and that closure of the flexible auxiliary domain is required to protect the transition state from bulk solvent.

  8. 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.

  9. 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.

  10. Bis(2-ethylhexyl)diglycolamic acid for the mutual separation of Europium (III) and Americium (III) from citric acid - nitric acid medium

    International Nuclear Information System (INIS)

    High-level liquid waste arises from fast reactor fuel reprocessing contains significant quantities of lanthanides and trivalent minor actinides. Recently, the partitioning of minor actinides from fast reactor-high active waste (FR-HAW) using a TRUEX solvent, composed of a solution of 0.2 M octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO)-1.2 M tri-n-butylphosphate (TBP) in n-dodecane is demonstrated. A new stripping formulation composed of a solution of 0.1 M citric acid in 0.1 M nitric acid was employed for back extraction of trivalents from the loaded TRUEX solvent. Thus the mutual separation lanthanides and actinides requires a suitable extractant for separating them from citric acid medium

  11. 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

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

    Science.gov (United States)

    Lu, Ling-li; Tian, Sheng-ke; Yang, Xiao-e; Peng, Hong-yun; Li, Ting-qiang

    2013-02-01

    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 (109)Cd increased significantly, and higher (109)Cd contents in roots and shoots were noted 24 h after uptake, when compared to controls. About 85% of the (109)Cd 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. PMID:23365009

  13. 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.

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

    Science.gov (United States)

    Lu, Ling-li; Tian, Sheng-ke; Yang, Xiao-e; Peng, Hong-yun; Li, Ting-qiang

    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. PMID:23365009

  15. Complexation of americium with humic, fulvic and citric acids at high ionic strength

    International Nuclear Information System (INIS)

    The stability constants of the Am3+ complexes of humic, fulvic and citric acids (HA, FA and Cit) were determined as a function of ionic strength (NaCl) using a solvent extraction technique. At a HA degree of ionization of 0.7 for the carboxylate groups, the Am-HA binding constant, log β1, varies from 8.3 at I = 0.2 m to 7.2 at I = 6.0 m. The log β1 of Am-Cit varies from 5.9 at I = 0.3 m to 5.10 at I = 5.0 m. Comparison of the binding constants of Am with HA, FA and Cit shows that, at high ionic strength, log β1 (AmCit) ∼ log β1(AmFA) ∼ {log β1(AmHA) - 1}. Comparison of the values of other metals indicate that the log β1 values for Cit can serve to estimate HA and FA. (orig.)

  16. Uranyl ion complexation by citric and citramalic acids in the presence of di-amines

    International Nuclear Information System (INIS)

    Uranyl nitrate reacts with citric (H4cit) or D-(-)-citramalic (H3citml) acids under mild hydrothermal conditions and in the presence of di-amines to give different complexes which are all characterized by the presence of 2:2 uranyl/poly-carboxylate di-anionic dimers or of polymeric chains based on the same dimeric motif. Each uranium ion is chelated by the two ligands through the alkoxide and the α- or β-carboxylate groups, the second β-carboxylic group in citrate being uncoordinated. The uranium coordination sphere is completed by either a water molecule or the β-carboxylate group of a neighboring unit, thus giving zero- or one-dimensional assemblages, respectively. The evidence for [UO2(Hcit)]2 dimers in the solid state confirms previous results from potentiometric and EXAFS measurements on solutions. Depending on the diamine used (DABCO, 2,2'- and 4,4'-bipyridine, [2.2.2]cryptand) and its ability to form divergent hydrogen bonds or not, different uranyl/poly-carboxylate topologies are obtained, thus evidencing template effects, and extended hydrogen bonding gives two- or three-dimensional assemblages. These results, together with those previously obtained with NaOH as a base, add to the knowledge of the uranyl/citrate system, which is much investigated for its environmental relevance. (author)

  17. An oral sodium citrate-citric acid non-particulate buffer in humans.

    Science.gov (United States)

    Hauptfleisch, J J; Payne, K A

    1996-11-01

    We have investigated the effect on the pH of the gastric fluid of a single dose of sodium citrate 0.3 mol litre-1 (antacid) and a solution containing sodium citrate dehydrate (100 mg ml-1) with citric acid monohydrate (66 mg ml-1) (buffer). The dose for both solutions was 0.4 ml kg-1 via a nasogastric tube. Each group comprised 10 patients undergoing neurosurgical operations of 5-7 h duration. A control group of 10 patients received no gastric solution. The pH of the gastric aspirate was measured hourly using a Metrohm 632 digital pH meter (Synectics Medical, Sweden). Mean baseline gastric pH was 2.64 (SD 1.71). In the control group, pH increased to 4.4 (1.51) at 5 h, returning to baseline at 7 h. In the antacid group, pH increased to 6.11 (0.47) at 15 min and decreased to 3.70 (1.94) at 7 h (P 0.01). Total mean gastric aspirate was 0.5 ml kg-1. PMID:8957982

  18. Fabrication and characterization of citric acid-modified starch nanoparticles/plasticized-starch composites.

    Science.gov (United States)

    Ma, Xiaofei; Jian, Ruijuan; Chang, Peter R; Yu, Jiugao

    2008-11-01

    Starch nanoparticles (SN) were prepared by delivering ethanol as the precipitant into starch-paste solution dropwise. Citric acid (CA) modified SN (CASN) were fabricated with the dry preparation technique. According to the characterization of CASN with Fourier transform infrared, X-ray diffraction, rapid visco analyzer, and scanning electron microscopy (SEM), amorphous CASN could not be gelatinized in hot water because of the cross-linking, and most of CASN ranged in size from about 50 to 100 nm. The nanocomposites were also prepared using CASN as the filler in glycerol plasticized-pea starch (GPS) matrix by the casting process. SEM revealed that CASN was dispersed evenly in the GPS matrix. As shown in dynamic mechanical thermal analysis, the introduction of CASN could improve the storage modulus and the glass transition temperature of CASN/GPS composites. The tensile yield strength and Young's modulus increased from 3.94 to 8.12 MPa and from 49.8 to 125.1 MPa, respectively, when the CASN contents varied from 0 to 4 wt %. Moreover, the values of water vapor permeability decreased from 4.76 x 10(-10) to 2.72 x 10(-10) g m(-1) s(-1) Pa(-1). The improvement of these properties could be attributed to the good interaction between CASN filler and GPS matrix. The comprehensive application of green chemistry principles were demonstrated in the preparation of CASN and CASN/GPS composites. PMID:18844405

  19. 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. PMID:17136437

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

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

    2016-11-01

    Highly crystalline anatase TiO2 nanoparticles with high BET surface area have been synthesized by thermal hydrolysis of titanium(IV) bis(ammoniumlactato) dihydroxide aqueous solutions. The photocatalytic H2 production from aqueous citric acid (CA) solutions over Pt-loaded TiO2 has been investigated under different experimental conditions, that is, different CA concentration, temperature, light intensity, and pH of Pt/TiO2 suspension. For comparison, the photocatalytic dehydrogenation of triethanolamine (TEA) has also been investigated. The highest H2 production rates were obtained at pH 3 and 9 for CA and TEA, respectively. This behavior is readily explained by the adsorption characteristic of the employed reagent on the surface of the charged TiO2. The effect of the photocatalyst loading and the light intensity on the H2 production rate showed the same behavior in the case of CA and TEA evincing that these parameters are catalyst dependent. The apparent activation energies have been determined to be 13.5 ± 1.8 and 14.7 ± 1.6 kJ mol(-1) for CA and TEA, respectively, indicating the existence of an activation energy barrier in a photocatalytic process which can be attributed to the desorption of adsorbed products. PMID:26930545

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

    Directory of Open Access Journals (Sweden)

    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.

  3. 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

  4. 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

    2016-06-01

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

  5. Effect of citric acid and polymer blend on characteristics of ofloxacin floating matrix tablets by factorial design

    OpenAIRE

    Bera, Hriday; Mandal, Bivash; Sinha, Chandrima; Dey, Sanjoy K.; Bera, Rammohan; Ghosh, Lakshmi K.

    2011-01-01

    The present investigation deals with the development of floating matrix tablet containing Ofloxacin, to prolong the gastric residence time, thereby effective in eradication of Helicobacter pylori from the gastric mucosa. A 32 factorial design was employed to formulate floating matrix tablet selecting polymer blend ratio [hydroxypropyl methylcellulose (HPMC) / sodium carboxymethylcellulose (SCMC)] and content of citric acid as independent variables. Time required for 50 % of drug release (t50 ...

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

    OpenAIRE

    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-retro...

  7. Effect of citric acid on photoelectrochemical properties of tungsten trioxide films prepared by the polymeric precursor method

    International Nuclear Information System (INIS)

    Effect of citric acid (CA) on microstructure and photoelectrochemical properties of WO3 films prepared by the polymeric precursor method was investigated. The obtained materials were characterized by means of X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and high-resolution transmission electron microscopy (HRTEM). The results showed that samples prepared with adding different amounts of citric acid had a pure phase of cubic. The addition of citric acid could significantly increase the particle size and change the surface of WO3 films. The photoelectrochemical measurements were performed using a standard three-electrode system cell. The films prepared from mass ratios of CA/PEG (R = 0, 0.2, 0.4, 0.6 and 1) showed 1.0, 1.4, 1.7, 2.1 and 0.9 mA cm-2 at 1.2 V under illumination with a 500 W xenon lamp (I0 = 100 mW/cm2), respectively.

  8. Improvement of production of citric acid from oil palm empty fruit bunches: optimization of media by statistical experimental designs.

    Science.gov (United States)

    Bari, Md Niamul; Alam, Md Zahangir; Muyibi, Suleyman A; Jamal, Parveen; Abdullah-Al-Mamun

    2009-06-01

    A sequential optimization based on statistical design and one-factor-at-a-time (OFAT) method was employed to optimize the media constituents for the improvement of citric acid production from oil palm empty fruit bunches (EFB) through solid state bioconversion using Aspergillus niger IBO-103MNB. The results obtained from the Plackett-Burman design indicated that the co-substrate (sucrose), stimulator (methanol) and minerals (Zn, Cu, Mn and Mg) were found to be the major factors for further optimization. Based on the OFAT method, the selected medium constituents and inoculum concentration were optimized by the central composite design (CCD) under the response surface methodology (RSM). The statistical analysis showed that the optimum media containing 6.4% (w/w) of sucrose, 9% (v/w) of minerals and 15.5% (v/w) of inoculum gave the maximum production of citric acid (337.94 g/kg of dry EFB). The analysis showed that sucrose (p<0.0011) and mineral solution (p<0.0061) were more significant compared to inoculum concentration (p<0.0127) for the citric acid production. PMID:19231166

  9. 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

  10. 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.

  11. 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

  12. Citric acid fermentation by Aspergillus niger: Induction of high yielding mutants with the help of radiation, combination treatments, protoplast fusion and genetic engineering

    International Nuclear Information System (INIS)

    Conidia of the citric acid fermenting fungal mutant Aspergillus niger 14/20 was subjected to the gamma radiation treatment. Mutants giving higher total titrable acid values than their parent strain were selected and tested under varied environmental and cultural conditions. After screening of about 2000 mutants, two of them with the highest yield of citric acid in molasses medium (62-76 mg/ml) were selected for further experiments. Further step-wise improvements of these strains are feasible, and radiation is a potential mutagen for the selection of better strains of microorganisms for the industrial use. The cassava starch has been found to be a fairly good substract for citric acid fermentation under the solid state condition and also when mixed with molasses in surface culture condition. Agro-industrial residues such as bagasse, rice straw and saw-dust could be used as a support for the fermentation of sugars to citric acid under the solid state conditions. The use of mixed culture method (amylolytic + citric acid fermenting organisms) had not been found to improve the citric acid fermentation from cassava as a basic substrate. (author). 2 refs

  13. 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.

  14. Mast cells in citric acid-induced cough of guinea pigs

    International Nuclear Information System (INIS)

    It was demonstrated previously that mast cells play an important role in citric acid (CA)-induced airway constriction. To investigate the role of mast cells in CA-induced cough, three experiments were carried out in this study. In the first experiment, 59 guinea pigs were employed and we used compound 48/80 to deplete mast cells, cromolyn sodium to stabilize mast cells, MK-886 to inhibit leukotriene synthesis, pyrilamine to antagonize histamine H1 receptor, methysergide to antagonize serotonin receptor, and indomethacin to inhibit cyclooxygenase. In the second experiment, 56 compound 48/80-pretreated animals were divided into two parts; the first one was used to test the role of exogenous leukotriene (LT) C4, while the second one to test the role of exogenous histamine in CA-induced cough. Each animal with one of the above pretreatments was exposed sequentially to saline (baseline) and CA (0.6 M) aerosol, each for 3 min. Then, cough was recorded for 12 min using a barometric body plethysmograph. In the third experiment, the activation of mast cells upon CA inhalation was investigated by determining arterial plasma histamine concentration in 17 animals. Exposure to CA induced a marked increase in cough number. Compound 48/80, cromolyn sodium, MK-886 and pyrilamine, but not indomethacin or methysergide, significantly attenuated CA-induced cough. Injection of LTC4 or histamine caused a significant increase in CA-induced cough in compound 48/80-pretreated animals. In addition, CA inhalation caused significant increase in plasma histamine concentration, which was blocked by compound 48/80 pretreatment. These results suggest that mast cells play an important role in CA aerosol inhalation-induced cough via perhaps mediators LTs and histamine

  15. New multifunctional pharmaceutical excipient in tablet formulation based on citric acid-cyclodextrin polymer.

    Science.gov (United States)

    Garcia-Fernandez, Maria José; Tabary, Nicolas; Chai, Feng; Cazaux, Frédéric; Blanchemain, Nicolas; Flament, Marie-Pierre; Martel, Bernard

    2016-09-25

    A β-cyclodextrin (β-CD) polymer obtained by crosslinking β-CD with citric acid in its water-insoluble (PCD-I) and soluble (PCD-S) forms was used as a multifunctional direct compression excipient for tablet designing. PCD-I powder was obtained after grinding the solid fraction through a 200μm grid. PCD-S powder was recovered after lyophilization or spray drying of the PCD-S aqueous solutions, eventually followed by a wet granulation step. Both PCD-I and PCD-S powders were characterized, separately and mixed in variable ratios, based on dynamic water vapor sorption, SEM, particle size distribution, tapped density, compressibility, and flowability. PCD-I and spray dried and lyophilized/wet granulated PCD-S, as well as the mixture PCD-I/PCD-S=90/10, presented optimal free flowing characteristics. Then, PCD-I or PCD-S powders - separately or mixed in variable ratios - were used for tablets preparation by direct compression without adding any other excipient (e.g. binder, lubricant, disintegrant etc). As PCD-I decreased, tablets resistance to crushing and disintegration time increased from 15s to 15min (against 30min for β-CD), showing the improved disintegrant functionality of PCD-I, that rapidly swelled once in contact with water. Finally, PCD was force-fed to Sprague-Dawley rats (2g/kg) which were then observed during 14days for any clinical signs of toxicity. PMID:27473278

  16. The role of mast cells in citric acid-induced airway constriction and cough.

    Science.gov (United States)

    Lai, Yih-Loong; Wu, Li-Ling; Lin, Tai-Yin; Lin, Chien-He

    2009-11-30

    Inhalation of citric acid (CA) causes airway constriction and coughing. To investigate the role of mast cells in CA-induced airway constriction and cough, three experiments using guinea pigs were carried out. In the first experiment, we used compound 48/80 to deplete mast cells, cromolyn sodium to stabilize mast cells, MK-886 to inhibit synthesis of leukotrienes, pyrilamine to antagonize histamine H1 receptor, methysergide to antagonize serotonin receptor, and indomethacin to inhibit cyclooxygenase. In the second experiment, compound 48/80-pretreated animals were divided into 2 parts; the first one was used to test the role of exogenous leukotriene (LT) C4, while the second one to test the role of exogenous histamine. Decreases in respiratory compliance (Crs) and forced expiratory volume in 0.1 sec (FEV0.1) were used as indicators for airway constriction in anesthetized guinea pigs. CA-induced cough was recorded for 12 min using a barometric body plethysmograph in conscious animals. In the third experiment, the activation of mast cells upon CA inhalation was investigated by determining lung tissue or arterial plasma histamine concentration in animals. Exposure to CA induced marked airway constriction and increase in cough number. Compound 48/80, cromolyn sodium, MK-886 and pyrilamine, but not indomethacin or methysergide, significantly attenuated CA-induced airway constriction and cough. Injection of LTC4 or histamine caused a significant increase in CA-induced airway constriction and cough in compound 48/80-pretreated animals. In addition, CA inhalation caused significant increase in lung tissue and plasma histamine concentrations, which were blocked by compound 48/80 pretreatment. These results suggest that mast cells play an important role in CA aerosol inhalation-induced airway constriction and cough via perhaps mediators including LTs and histamine. PMID:20359123

  17. 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.

  18. Stimulation of germination of conidium Aspergillus niger, a citric acid producer, under the action of mutagenic factors

    International Nuclear Information System (INIS)

    The action of low doses of various mutagens, namely, 2% cyclophosphane solution (30 min), 1% thiophosphamide solution (30 min), 0.05% nitrosomethylurea solution (30 and 60 min), γ-rays (10 krads) and UV-rays (10000 erg/mm2) stimulates germination of conidium Aspergillus niger, a citric acid producer. At the above-mentioned doses of mutagens, a minor quantity of morphological varieties are formed, and the variability value of acid production by Asp. niger is maintained at the spontaneous level

  19. The Citrus transcription factor, CitERF13, regulates citric acid accumulation via a protein-protein interaction with the vacuolar proton pump, CitVHA-c4.

    Science.gov (United States)

    Li, Shao-jia; Yin, Xue-ren; Xie, Xiu-lan; Allan, Andrew C; Ge, Hang; Shen, Shu-ling; Chen, Kun-song

    2016-01-01

    Organic acids are essential to fruit flavor. The vacuolar H(+) transporting adenosine triphosphatase (V-ATPase) plays an important role in organic acid transport and accumulation. However, less is known of V-ATPase interacting proteins and their relationship with organic acid accumulation. The relationship between V-ATPase and citric acid was investigated, using the citrus tangerine varieties 'Ordinary Ponkan (OPK)' and an early maturing mutant 'Zaoshu Ponkan (ZPK)'. Five V-ATPase genes (CitVHA) were predicted as important to citric acid accumulation. Among the genes, CitVHA-c4 was observed, using a yeast two-hybrid screen, to interact at the protein level with an ethylene response factor, CitERF13. This was verified using bimolecular fluorescence complementation assays. A similar interaction was also observed between Arabidopsis AtERF017 (a CitERF13 homolog) and AtVHA-c4 (a CitVHA-c4 homolog). A synergistic effect on citric acid levels was observed between V-ATPase proteins and interacting ERFs when analyzed using transient over-expression in tobacco and Arabidopsis mutants. Furthermore, the transcript abundance of CitERF13 was concomitant with CitVHA-c4. CitERF13 or AtERF017 over-expression leads to significant citric acid accumulation. This accumulation was abolished in an AtVHA-c4 mutant background. ERF-VHA interactions appear to be involved in citric acid accumulation, which was observed in both citrus and Arabidopsis. PMID:26837571

  20. 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.

  1. 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.

  2. Synthesis of WO3 nanoparticles by citric acid-assisted precipitation and evaluation of their photocatalytic properties

    International Nuclear Information System (INIS)

    Graphical abstract: Display Omitted Highlights: ► WO3 nanoparticles were synthesized by a simple citric acid-assisted precipitation. ► WO3 photocatalyst was able to the partial mineralization of rhB, IC and MO. ► WO3 can be considered as a photocatalyst active under visible light irradiation. -- Abstract: WO3 nanoparticles were synthesized by citric acid-assisted precipitation method using a 1:1.5 molar ratio of ammonium paratungstate hydrate (H42N10O42W12·xH2O):citric acid (C6H8O7). The formation of monoclinic crystal structure of WO3 at different temperatures was confirmed by X-ray powder diffraction (XRD). The characterization of the samples synthesized was complemented by transmission electron microscopy (TEM), Brunauer–Emmitt–Teller surface area (BET) and diffuse reflectance spectroscopy (DRS). According to the thermal treatment followed during the synthesis of WO3, the morphology of the nanoparticles formed was characterized by rectangular and ovoid shapes. The photocatalytic activity of WO3 obtained under different experimental conditions was evaluated in the degradation of rhodamine B (rhB), indigo carmine (IC), methyl orange (MO), and Congo red (CR) in aqueous solution under UV and UV–vis radiation. The highest photocatalytic activity was observed in the sample obtained by thermal treatment at 700 °C. In general, the sequence of degradation of the organic dyes was: indigo carmine (IC) > rhodamine B (rhB) > methyl orange (MO) > Congo red (CR). The mineralization degree of organic dyes by WO3 photocatalysts was determined by total organic carbon analysis (TOC) reaching percentages of mineralization of 82% (rhB), 85% (IC), 28% (MO), and 7% (CR) for 96 h of lamp irradiation.

  3. The relation of high fat diet, metabolic disturbances and brain oxidative dysfunction: modulation by hydroxy citric acid

    OpenAIRE

    Kamel Hamdy H; Amin Kamal A; Abd Eltawab Mohamed A

    2011-01-01

    Abstract Aims This study aimed to examine the effect of high fat diet (HFD) to modulate brain dysfunction, and understand the linkages between obesity, metabolic disturbances and the brain oxidative stress (BOS) dysfunction and modulation with hydroxyl citric acid of G. Cambogia. Methods Rats were divided into 3 groups; 1st control, maintained on standard normal rat chow diet, 2nd HFD, maintained on high fat diet along 12 week and 3rd HFD+G, administered G. Cambogia for 4 weeks and each group...

  4. Pulse electrodeposition of Pt and Pt–Ru methanol-oxidation nanocatalysts onto carbon nanotubes in citric acid aqueous solutions

    International Nuclear Information System (INIS)

    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

  5. 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 (grape pomace at industrial level. PMID:24721067

  6. Citric acid production from glycerol-containing waste of biodiesel industry by Yarrowia lipolytica in batch, repeated batch, and cell recycle regimes

    Energy Technology Data Exchange (ETDEWEB)

    Rymowicz, Waldemar; Rywinska, Anita [Wroclaw Univ. of Environmental and Life Sciences (Poland). Dept. of Biotechnology and Food Microbiology; Fatykhova, Alina R.; Kamzolova, Svetlana V.; Morgunov, Igor G. [Russian Academy of Sciences, Pushchino (Russian Federation). G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms

    2010-07-15

    Yarrowia lipolytica A-101-1.22 produces high citric acid (112 g l{sup -1}) with a yield of 0.6 g g{sup -1} and a productivity of 0.71 g l{sup -1} h{sup -1} during batch cultivation in the medium with glycerol-containing waste of biodiesel industry. However, it was observed that the specific citric acid production rate, which was maximal at the beginning of the biosynthesis, gradually decreases in the late production phase and it makes continuation of the process over 100 h pointless. The cell recycle and the repeated batch regimes were performed as ways for prolongation of citric acid synthesis by yeast. Using cell recycle, the active citric acid biosynthesis (96-107 g l{sup -1}) with a yield of 0.64 g g{sup -1} and a productivity of 1.42 g l{sup -1} h{sup -1} was prolongated up to 300 h. Repeated batch culture remained stable for over 1000 h; the RB variant of 30% feed every 3 days showed the best results: 124.2 g l{sup -1} citric acid with a yield of 0.77 g g{sup -1} and a productivity of 0.85 g l{sup -1} h{sup -1}. (orig.)

  7. 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

  8. Decontamination efficiency of citric acid and dissolution reaction of Fe3+ ion on TRIGA soil artificially contaminated with Co2+ ion

    International Nuclear Information System (INIS)

    A series of batch scale experiments was conducted to investigated the decontamination efficiency of citric acid on TRIGA soil artificially contaminated with Co2+ ion in the concentration range from 0.005M to 0.1M, under the pH solution of 3.0 to 10.0. The fraction diagram was calculated by equilibrium constant of Co2+ ion, Fe3+ ion and citric acid. The desorption rate of Co2+ ion was increased at low pH, but it was decreased at base zone. The dissolution rate of Fe3+ ion was same result against the various pH. The desorption reaction of Co2+ ion and the dissolution reaction of Fe3+ ion by citric acid both in acid solution and in base solution were suggested

  9. Thorium(IV) removal from aqueous medium by citric acid treated mangrove endophytic fungus Fusarium sp. ZZF51

    International Nuclear Information System (INIS)

    Highlights: • The mangrove endophytic fungus. They own special species and metabolic approaches. • Chemical treatment with citric acid. Improving the cation exchange capacity. • Explain adsorption mechanism combined with FTIR spectroscopy and kinetic models. -- Abstract: Thorium(IV) biosorption is investigated by citric acid treated mangrove endophytic fungus Fussarium sp. ZZF51 (CA-ZZF51) from South China Sea. The biosorption process was optimized at pH 4.5, equilibrium time 90 min, initial thorium(IV) concentration 50 mg L−1 and adsorbent dose 0.6 g L−1 with 90.87% of removal efficiency and 75.47 mg g−1 of adsorption capacity, which is obviously greater than that (11.35 mg g−1) of the untreated fungus Fussarium sp. ZZF51 for thorium(IV) biosorption under the condition of optimization. The experimental data are analyzed by using isotherm and kinetic models. Kinetic data follow the pseudo-second-order model and equilibrium data agree very well with the Langmuir model. In addition, FTIR analysis indicates that hydroxyl, amino, and carbonyl groups act as the important roles in the adsorption process

  10. 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 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. PMID:19723178

  11. Effects of Tetracycline, EDTA and Citric Acid Application on Nonfluorosed and Fluorosed Dentin: An In Vitro Study

    Science.gov (United States)

    Sadanand, K.; Vandana, K. L.

    2016-01-01

    Fluorosis is one of the factors that may bring about mineralization changes in teeth. Routine treatment of root biomodification is commonly followed during Periodontal therapy. Background: The Purpose of the present study was to compare and evaluate the morphological changes in fluorosed and nonfluorosed root dentin subsequent to the application of Tetracycline, EDTA and Citric acid. Both fluorosed and nonfluorosed teeth comprising of periodontally healthy and diseased were included in this study. Method: Each of them was grouped into Tetracycline Hydrochloride, EDTA and Citric acid treatment groupes. Using scanning electron microscope (SEM), the photomicrographs of dentin specimens were obtained. Results: Showed that there was no significant difference in exposure of number of tubules in different groups, while significant increase in the tubular width and tubular surface area was seen in fluorosed healthy, followed by fluorosed diseased groups, nonfluorosed healthy and nonfluorosed diseased groups after root biomodification procedure using various root conditioning agents. The root biomodification procedure brings in definite difference between fluorosed and nonfluorosed dentin specimens. PMID:27335611

  12. 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. PMID:23122734

  13. Effects of pH and citric acid contents on characteristics of ester-derived BaFe12O19 powder

    International Nuclear Information System (INIS)

    The single domain size of BaFe12O19 powder with crystallite sizes less than 200 nm was produced using a citric acid precursor method. Fe3+ and Ba2+, in a molar ratio of 12, were chelated by COOH- in an aqueous solution. After ethylene glycol additions, esterification, dehydration, and calcination led to the formation of ester-derived BaFe12O19 powder. High pH and/or high citric acid contents in the starting solution are required to complete chelate metallic ions in the solution and to form pure barium ferrite powder at 1073 K. Pure single magnetic domain BaFe12O19 particles of M(30 kOe)∼54 emu/g, Mr∼28 emu/g, and Hc∼3.7 kOe were produced using [citric acid]/[metallic ions]=1.5 and pH≥7

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

    OpenAIRE

    Noushin eGhazijahani; Ebrahim eHadavi; Byoung Ryong eJeong

    2014-01-01

    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, p...

  15. Study of apparent molal volume and viscosity of mutual citric acid and disodium hydrogen orthophosphate aqueous systems

    Indian Academy of Sciences (India)

    Man Singh

    2006-05-01

    Fundamental properties, density () and viscosity (), of citric acid (CA) and disodium hydrogen orthophosphate (DSP) at various strengths were obtained at different temperatures. The and values were used to determine apparent molal volumes and viscosity of systems. The , and values were regressed against molality for ρ0, 0 and $V^{0}_{\\phi}$f, the limiting constants at infinite dilution ( → 0) forionic and molecular interactions. The ρ0 and $V^{0}_{\\phi}$f of aq. acids are higher than those of aq. DSP and the viscosity of DSP is higher than that of aq. CA. Examination of ρ0 and $V^{0}_{\\phi}$ functions indicates that mutual compositions of CA and DSP counterbalance concentration and temperature effects on pH in bioprocesses.

  16. Dissolution of nickel ferrite and rare earths containing magnetites in citric acid - EDTA - gallic acid (CEG) formulation

    International Nuclear Information System (INIS)

    complete dissolution) taken in a 1.4:1.4:1.7 CEG formulation yielded a rate constant of 7.55 x 10-2 min-1. It is concluded that the presence of rare earths in magnetite at low amounts has not affected the dissolution characteristics of magnetite in CEG formulation. This conclusion corroborates a similar observed behaviour in citric acid-EDTA-ascorbic acid (CEA) formulation. The main advantage of CEG formulation over CEA formulation seems to be its stability towards radiation induced decomposition, a consideration important when chemical decontamination is planned under a short shutdown period (a few days) of the reactor. (authors)

  17. Enhanced citric acid production in aspergillus with inactivated asparagine-linked glycosylation protein 3 (ALG3), and/or increased laeA expression

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Ziyu; Baker, Scott E.

    2015-12-08

    Provided herein are fungi, such as Aspergillus niger, having a dolichyl-P-Man:Man(5)GlcNAc(2)-PP-dolichyl mannosyltransferase (Alg3) gene genetic inactivation, increased expression of a loss of aflR expression A (Lae), or both. In some examples, such mutants have several phenotypes, including an increased production of citric acid relative to the parental strain. Methods of using the disclosed fungi to make citric acid are also provided, as are compositions and kits including the disclosed fungi.

  18. Minimal inhibitory concentrations of undissociated lactic, acetic, citric and propionic acid for Listeria monocytogenes under conditions relevant to cheese.

    Science.gov (United States)

    Wemmenhove, Ellen; van Valenberg, Hein J F; Zwietering, Marcel H; van Hooijdonk, Toon C M; Wells-Bennik, Marjon H J

    2016-09-01

    Minimal inhibitory concentrations (MICs) of undissociated lactic acid were determined for six different Listeria monocytogenes strains at 30 °C and in a pH range of 4.2-5.8. Small increments in pH and acid concentrations were used to accurately establish the growth/no growth limits of L. monocytogenes for these acids. The MICs of undissociated lactic acid in the pH range of 5.2-5.8 were generally higher than at pH 4.6 for the different L. monocytogenes strains. The average MIC of undissociated lactic acid was 5.0 (SD 1.5) mM in the pH range 5.2-5.6, which is relevant to Gouda cheese. Significant differences in MICs of undissociated lactic acid were found between strains of L. monocytogenes at a given pH, with a maximum observed level of 9.0 mM. Variations in MICs were mostly due to strain variation. In the pH range 5.2-5.6, the MICs of undissociated lactic acid were not significantly different at 12 °C and 30 °C. The average MICs of undissociated acetic acid, citric acid, and propionic acid were 19.0 (SD 6.5) mM, 3.8 (SD 0.9) mM, and 11.0 (SD 6.3) mM, respectively, for the six L. monocytogenes strains tested in the pH range 5.2-5.6. Variations in MICs of these organic acids for L. monocytogenes were also mostly due to strain variation. The generated data contribute to improved predictions of growth/no growth of L. monocytogenes in cheese and other foods containing these organic acids. PMID:27217360

  19. Characterization of sericin powder prepared from citric acid-degraded sericin polypeptides of the silkworm, Bombyx Mori.

    Science.gov (United States)

    Kurioka, Akira; Kurioka, Fujie; Yamazaki, Masayoshi

    2004-04-01

    Acid-degraded sericin powder (AC-SP) was prepared from aqueous solution containing citric acid-degraded sericin polypeptides of Bombyx mori. The morphological and biochemical properties of AC-SP were compared with those of alkali-degraded sericin powder (AL-SP) and hot-water degraded sericin powder (HW-SP). Based on an SEM analysis, AC-SP showed a thin film structure of 10-100 microm with good dispersity while AL-SP and HW-SP had a much larger thin film structure (<500 microm). The extract of AC-SP showed stronger trypsin inhibitor activity due to cocoon shell trypsin inhibitor (CSTI-IV) than that of HW-SP. The extract of AL-SP showed no CSTI-IV activity. It was found that AC-SP was a trypsin inhibitor complex powder and that the release of CSTI-IV from AC-SP depended on pH and ion strength. Similar powder materials were obtained when such organic acids as tartaric acid and succinic acid were used. These results suggest that the acid-degraded sericin polypeptides work as a protein matrix to which CSTI-IV may bind ionically. PMID:15118302

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

    OpenAIRE

    Ghazijahani, Noushin; Hadavi, Ebrahim; Jeong, Byoung R.

    2014-01-01

    The effect of foliar application of two levels of citric acid (CA; 0 and 7 mM) and two levels of salicylic acid (SA; 0 and 1 mM) combined with two levels of nutrient solution strength (full strength and half strength) on mineral acquisition by sweet basil were investigated. The experiment was conducted in a randomized block design arrangement with three replications. SA alone reduced the plant height and thickened the stem. Plants supplied with a full strength solution had a ticker stem, prod...

  1. High performance B doped BiVO4 photocatalyst with visible light response by citric acid complex method.

    Science.gov (United States)

    Wang, Min; Zheng, Haoyan; Liu, Qiong; Niu, Chao; Che, Yinsheng; Dang, Mingyan

    2013-10-01

    A B-doped BiVO4 photocatalyst was synthesized by citric acid complex method and using H3BO3 as the dopant source, and the photocatalyst was characterized with XPS, XRD, SEM, BET and UV-Vis DRS. The photocatalytic activity was evaluated by the photocatalytic degradation of a methyl orange (MO) solution under visible light. This assay revealed that both the pure BiVO4 and all of the B doped samples were the monoclinic phase. Doping the BiVO4 with B increased the number of V(4+) and oxygen vacancies, which led to the red shift of the absorbing boundary of the B-doped BiVO4 but had little influence on the morphology and crystal size. The B doping improved the photocatalytic activity, and the highest photocatalytic degradation rate of 98% occurred with a B dopant concentration of 0.04. PMID:23751222

  2. Evaluation and optimization of growth and citric acid production by Yarrowia lipolytica NRRL Y-1095 using glycerol as carbon source as an alternative to use biodiesel byproduct

    Directory of Open Access Journals (Sweden)

    Avila-Neto P M

    2014-02-01

    Full Text Available The aim of the present study was to optimize growth and citric acid production by Yarrowia lipolytica NRRL Y-1095 using glycerol as the sole carbon source, like an alternative to use biodiesel glycerol, a promising and cheap carbon source. Fermentations were performed in Erlenmeyer flasks to optimize growth and citrate production from glycerol. The fermented broth was analyzed by HPLC equipped with a UV and RI detector to evaluate isocitrate, citrate and glycerol consumption. The growth medium was optimized in flasks and in batch fermentation. The present study have optimized media conditions for the growth phase of Yarrowia lipolityca NRRL Y-1095 using experimental design and surface response methodology, obtaining 6.18 g.l-1 of dry cell weight (DCW and up to 22 g.l-1 DCW in bioreactor after 96 h. Six fermentations were performed in a feed batch reactor with varying aeration and agitation. Dissolved oxygen was an important factor and a 0.5 yield of citric acid was obtained from feed batch fermentation, where up to 59 g.l-1 of citric acid was obtained. Glycerol is a cheap alternative to citric acid production since biodiesel glycerol production is growing rapidly and becoming an environmental problem.

  3. Foliar Sprays of Citric Acid and Malic Acid Modify Growth, Flowering, and Root to Shoot Ratio of Gazania (Gazania rigens L.: A Comparative Analysis by ANOVA and Structural Equations Modeling

    Directory of Open Access Journals (Sweden)

    Majid Talebi

    2014-01-01

    Full Text Available Foliar application of two levels of citric acid and malic acid (100 or 300 mg L−1 was investigated on flower stem height, plant height, flower performance and yield indices (fresh yield, dry yield and root to shoot ratio of Gazania. Distilled water was applied as control treatment. Multivariate analysis revealed that while the experimental treatments had no significant effect on fresh weight and the flower count, the plant dry weight was significantly increased by 300 mg L−1 malic acid. Citric acid at 100 and 300 mg L−1 and 300 mg L−1 malic acid increased the root fresh weight significantly. Both the plant height and peduncle length were significantly increased in all applied levels of citric acid and malic acid. The display time of flowers on the plant increased in all treatments compared to control treatment. The root to shoot ratio was increased significantly in 300 mg L−1 citric acid compared to all other treatments. These findings confirm earlier reports that citric acid and malic acid as environmentally sound chemicals are effective on various aspects of growth and development of crops. Structural equations modeling is used in parallel to ANOVA to conclude the factor effects and the possible path of effects.

  4. A study of partial molar volumes of citric acid and tartaric acid in water and binary aqueous mixtures of ethanol at various temperatures

    Indian Academy of Sciences (India)

    M L Parmar; R K Awasthi; M K Guleria

    2004-01-01

    Partial molar volumes of citric acid and tartaric acid have been determined in water and binary aqueous mixtures of ethanol (5, 10, 15, 20 and 25% by weight of ethanol) at different temperatures and acid concentrations from the solution density measurements. The data have been evaluated by using Masson equation and the obtained parameters have been interpreted in terms of solute-solvent interactions. The partial molar volumes vary with temperature as a power series of temperature. Structure making/breaking capacities of the organic acids have been inferred from the sign of [2$\\phi^{0}_{v}$/2], i.e. secondderivative of partial molar volume with respect to temperature at constant pressure. Both the organic acids behave as structure breakers in water and water + ethanol.

  5. Human tooth enamel dissolution in citric acid as a function of degree of saturation and pH

    CERN Document Server

    Barbour, M E

    2002-01-01

    There is increasing concern among the dental community regarding the damage caused to teeth by the acids in soft drinks. Enamel dissolution in acidic solution can be reduced by addition of calcium and/or phosphate salts to increase the degree of saturation with respect to hydroxyapatite (DS sub H sub A), or by an increase in pH. In soft drinks, however, both of these approaches are associated with a reduced taste quality. The separate effects of each parameter are not known. In the work presented here, enamel dissolution was studied in citric acid solutions with compositions typical of soft drinks. Nanoindentation and atomic force microscopy (AFM) were used to investigate very early stages of enamel dissolution, with typical exposure times of 30-600 s. Preliminary investigations of the application of SIMS, ESEM and XPS to enamel dissolution studies are also reported. The individual effects of DS sub H sub A , pH and calcium and phosphate concentrations on enamel dissolution have been investigated. It was show...

  6. Effect of stevia and citric acid on the stability of phenolic compounds and in vitro antioxidant and antidiabetic capacity of a roselle (Hibiscus sabdariffa L.) beverage.

    Science.gov (United States)

    Pérez-Ramírez, Iza F; Castaño-Tostado, Eduardo; Ramírez-de León, José A; Rocha-Guzmán, Nuria E; Reynoso-Camacho, Rosalía

    2015-04-01

    Plant infusions are consumed due to their beneficial effects on health, which is attributed to their bioactive compounds content. However, these compounds are susceptible to degradation during processing and storage. The objective of this research was to evaluate the effect of stevia and citric acid on the stability of phenolic compounds, antioxidant capacity and carbohydrate-hydrolysing enzyme inhibitory activity of roselle beverages during storage. The optimum extraction conditions of roselle polyphenolic compounds was of 95 °C/60 min, which was obtained by a second order experimental design. The incorporation of stevia increased the stability of colour and some polyphenols, such as quercetin, gallic acid and rosmarinic acid, during storage. In addition, stevia decreased the loss of ABTS, DPPH scavenging activity and α-amylase inhibitory capacity, whereas the incorporation of citric acid showed no effect. These results may contribute to the improvement of technological processes for the elaboration of hypocaloric and functional beverages. PMID:25442634

  7. The effect of EDTA and citric acid on phytoremediation of Cd, Cr, and Ni from soil using Helianthus annuus

    International Nuclear Information System (INIS)

    The possibility to clean heavy metal contaminated soils with hyperaccumulator plants has shown great potential. One of the most recently studied species used in phytoremediation applications are sunflowers. In this study, two cultivars of Helianthus annuus were used in conjunction with ethylene diamine tetracetic acid (EDTA) and citric acid (CA) as chelators. Two different concentrations of the chelators were studied for enhancing the uptake and translocation of Cd, Cr, and Ni from a silty-clay loam soil. When 1.0 g/kg CA was used, the highest total metal uptake was only 0.65 mg. Increasing the CA concentration posed a severe phytotoxicity to both cultivars as evidenced by stunted growth and diminished uptake rates. Decreasing the CA concentration to 0.1 and 0.3 g/kg yielded results that were not statistically different from the control. EDTA at a concentration of 0.1 g/kg yielded the best results for both cultivars achieving a total metal uptake of ∼0.73 mg compared to ∼0.40 mg when EDTA was present at 0.3 g/kg

  8. The effect of EDTA and citric acid on phytoremediation of Cd, Cr, and Ni from soil using Helianthus annuus

    Energy Technology Data Exchange (ETDEWEB)

    Turgut, Cafer; Katie Pepe, M.; Cutright, Teresa J

    2004-09-01

    The possibility to clean heavy metal contaminated soils with hyperaccumulator plants has shown great potential. One of the most recently studied species used in phytoremediation applications are sunflowers. In this study, two cultivars of Helianthus annuus were used in conjunction with ethylene diamine tetracetic acid (EDTA) and citric acid (CA) as chelators. Two different concentrations of the chelators were studied for enhancing the uptake and translocation of Cd, Cr, and Ni from a silty-clay loam soil. When 1.0 g/kg CA was used, the highest total metal uptake was only 0.65 mg. Increasing the CA concentration posed a severe phytotoxicity to both cultivars as evidenced by stunted growth and diminished uptake rates. Decreasing the CA concentration to 0.1 and 0.3 g/kg yielded results that were not statistically different from the control. EDTA at a concentration of 0.1 g/kg yielded the best results for both cultivars achieving a total metal uptake of {approx}0.73 mg compared to {approx}0.40 mg when EDTA was present at 0.3 g/kg.

  9. Nanoporous alumina formed by self-organized two-step anodization of Ni3Al intermetallic alloy in citric acid

    International Nuclear Information System (INIS)

    Highlights: ► Anodic porous alumina was formed by Ni3Al intermetallic alloy anodization. ► The anodizations were conducted in 0.3 M citric acid. ► Nanopores geometry depends on anodizing voltage. ► No barrier layer was formed during anodization. - Abstract: Formation of the nanoporous alumina on the surface of Ni3Al intermetallic alloy has been studied in details and compared with anodization of aluminum. Successful self-organized anodization of this alloy was performed in 0.3 M citric acid at voltages ranging from 2.0 to 12.0 V using a typical two-electrode cell. Current density records revealed different mechanism of the porous oxide growth when compared to the mechanism pertinent for the anodization of aluminum. Electrochemical impedance spectroscopy experiments confirmed the differences in anodic oxide growth. Surface and cross-sections of the Ni3Al intermetallic alloy with anodic oxide were observed with field-emission scanning electron microscope and characterized with appropriate software. Nanoporous oxide growth rate was estimated from cross-sectional FE-SEM images. The lowest growth rate of 0.14 μm/h was found for the anodization at 0 °C and 2.0 V. The highest one – 2.29 μm/h – was noticed for 10.0 V and 30 °C. Pore diameter was ranging from 18.9 nm (2.0 V, 0 °C) to 32.0 nm (12.0 V, 0 °C). Interpore distance of the nanoporous alumina was ranging from 56.6 nm (2.0 V, 0 °C) to 177.9 nm (12.0 V, 30 °C). Pore density (number of pore occupying given area) was decreasing with anodizing voltage increase from 394.5 pores/μm2 (2.0 V, 0 °C) to 94.9 pores/μm2 (12.0 V, 0 °C). All the geometrical features of the anodic alumina formed by two-step self-organized anodization of Ni3Al intermetallic alloy are depending on the operating conditions.

  10. Mechanochemically assisted solid-state and citric acid complex syntheses of Cu-doped sodium cobaltite ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Pršić, S., E-mail: sanjaprsic@imsi.bg.ac.rs [Institute for Multidisciplinary Research, University of Belgrade, Kneza Višeslava 1, 11030 Belgrade (Serbia); Savić, S.M., E-mail: slavicas@imsi.bg.ac.rs [Institute for Multidisciplinary Research, University of Belgrade, Kneza Višeslava 1, 11030 Belgrade (Serbia); Branković, Z., E-mail: zorica.brankovic@imsi.bg.ac.rs [Institute for Multidisciplinary Research, University of Belgrade, Kneza Višeslava 1, 11030 Belgrade (Serbia); Vrtnik, S., E-mail: stane.vrtnik@ijs.si [Institute Jožef Stefan, Condensed Matter Physics, Jamova cesta 39, 1000 Ljubljana (Slovenia); Dapčević, A., E-mail: hadzi-tonic@tmf.bg.ac.rs [Department of General and Inorganic Chemistry, Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11120 Belgrade (Serbia); Branković, G., E-mail: goran.brankovic@imsi.bg.ac.rs [Institute for Multidisciplinary Research, University of Belgrade, Kneza Višeslava 1, 11030 Belgrade (Serbia)

    2015-08-15

    Highlights: • Sodium cobaltite was synthesized by mechanochemically assisted solid-state reaction and citric acid complex (CAC) method. • We investigated effect of Cu-doping in NaCo{sub 2−x}Cu{sub x}O{sub 4} (x = 0, 0.01, 0.03, 0.05). • ICP analysis showed that the controlling of the samples composition is easier by the CAC method. • The Seebeck coefficient in Cu-doped samples was higher compared to the undoped one. • The highest figure of merit was observed in the sample with the lowest Cu concentration. - Abstract: In the last decade, the sodium cobaltite ceramic became a promising candidate for potential thermoelectric applications, because of its large thermopower and low resistivity. In this work, polycrystalline samples of NaCo{sub 2−x}Cu{sub x}O{sub 4} (x = 0, 0.01, 0.03, 0.05) were prepared using mechanochemically assisted solid-state reaction method (MASSR) and the citric acid complex method (CAC). Bulk samples were prepared by pressing into disc-shaped pellets and subsequently subjected to a thermal treatment at 880 °C in inert argon atmosphere. Changes in structural and microstructural characteristics of the samples, caused by the substitution of Cu for Co, were characterized using X-ray diffraction (XRD) analysis, and scanning electron microscopy (SEM), respectively. The results of inductively coupled plasma (ICP) analysis showed that the compositions of the final products correspond to γ-NaCo{sub 2}O{sub 4} and confirmed that desired compound was obtained in both syntheses procedures. The advantages and disadvantages of these two syntheses procedures have been observed and discussed: the CAC method enabled obtaining samples with higher density and fine microstructure compared to the MASSR method, thus better thermoelectric properties. The Cu{sup 2+} substitution led to the increase in Seebeck coefficient in both synthesis routes. The highest figure of merit of 0.022 at 300 K was observed for the sample doped with 1 mol% Cu, obtained by

  11. The Citrus transcription factor, CitERF13, regulates citric acid accumulation via a protein-protein interaction with the vacuolar proton pump, CitVHA-c4

    OpenAIRE

    Shao-jia Li; Xue-ren Yin; Xiu-lan Xie; Andrew C. Allan; Hang Ge; Shu-ling Shen; Kun-song Chen

    2016-01-01

    Organic acids are essential to fruit flavor. The vacuolar H+ transporting adenosine triphosphatase (V-ATPase) plays an important role in organic acid transport and accumulation. However, less is known of V-ATPase interacting proteins and their relationship with organic acid accumulation. The relationship between V-ATPase and citric acid was investigated, using the citrus tangerine varieties ‘Ordinary Ponkan (OPK)’ and an early maturing mutant ‘Zaoshu Ponkan (ZPK)’. Five V-ATPase genes (CitVHA...

  12. Determination of cholesterol oxides in anchovies (Engraulis encrasicolus treated with a commercial mixture of citric acid, trisodium acid and hydrogen peroxide

    Directory of Open Access Journals (Sweden)

    Aniello Anastasio

    2013-02-01

    Full Text Available A new additive formulation containing hydrogen peroxide, citric acid and trisodium acid is illegally used in fishery products due its whitening and antioxidant features. Aim of this study was to evaluate the possible presence of COPs and their role as markers of illegal treatment in anchovies (Engraulis encrasicolus stored at different temperatures. Sensory analysis was also performed by the specific QIM test. The quantitative determinations (% of cholesterol oxides (COPs showed changing amounts during storage. Not always The COPs measured in the treated samples were significantly higher than control samples. Considering the volatility of hydrogen peroxide and the poor repeatability of COPs analyses, as shown in the present study, it is crucial to intensify the control by the Authorities.

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

    Science.gov (United States)

    Ghazijahani, Noushin; Hadavi, Ebrahim; Jeong, Byoung R

    2014-01-01

    The effect of foliar application of two levels of citric acid (CA; 0 and 7 mM) and two levels of salicylic acid (SA; 0 and 1 mM) combined with two levels of nutrient solution strength (full strength and half strength) on mineral acquisition by sweet basil were investigated. The experiment was conducted in a randomized block design arrangement with three replications. SA alone reduced the plant height and thickened the stem. Plants supplied with a full strength solution had a ticker stem, produced more biomass, and showed higher values of Fv/Fm. Some changes in the uptake pattern of some nutrients, especially boron and sulfur, were noticed. Higher boron concentrations in leaves were in plants sprayed with a combination of 7 mM CA and 1 mM of SA. Applying combination of CA and SA was more effective than using them individually that suggests an effective synergism between them. PMID:25400645

  14. Reclamation of copper-contaminated soil using EDTA or citric acid coupled with dissolved organic matter solution extracted from distillery sludge

    International Nuclear Information System (INIS)

    Soil washing using a strong chelating agent is a common practice for restoring contaminated soils, but significant soil fertility degradation and high operation costs are the major disadvantages. Washing soil with a dissolved organic matter (DOM) solution has been identified as a method that can moderate the loss of nutrients in the soil and enhance metal removal. The DOM solutions were extracted from waste sludge obtained from a local whisky distillery. Single chelating washing and chelate-DOM washing were carried out using ethylenediaminetetraacetic acid (EDTA), citric acid, and DOM solutions to remediate highly Cu-contaminated soil. Two-phase washing using 0.34 M citric acid and then 1500 mg L−1 DOM solution (pH 8.5) was found to be most favorable for the soil. With this treatment, 91% Cu was removed from the topsoil; the organic matter, cation exchange capacity, plant-available nitrogen, and available phosphate content increased by 28.1%, 103%, 17.7%, and 422%, respectively. -- Highlights: •We employ dissolved organic matter (DOM) solution to partially substitute EDTA or citric acid for soil washing. •Moderately-contaminated subsoil can be successfully remediated by sequential DOM washing. •Soil fertility deteriorates if soil is washed with EDTA or citric acid alone. •The loss of soil fertility has been reduced by performing two-phase the chelate-DOM washing. -- Washing the soil with the two-phase chelate-DOM method could remove quantities of Cu and reserve most of fertility in soil

  15. Human tooth enamel dissolution in citric acid as a function of degree of saturation and pH

    International Nuclear Information System (INIS)

    There is increasing concern among the dental community regarding the damage caused to teeth by the acids in soft drinks. Enamel dissolution in acidic solution can be reduced by addition of calcium and/or phosphate salts to increase the degree of saturation with respect to hydroxyapatite (DSHA), or by an increase in pH. In soft drinks, however, both of these approaches are associated with a reduced taste quality. The separate effects of each parameter are not known. In the work presented here, enamel dissolution was studied in citric acid solutions with compositions typical of soft drinks. Nanoindentation and atomic force microscopy (AFM) were used to investigate very early stages of enamel dissolution, with typical exposure times of 30-600 s. Preliminary investigations of the application of SIMS, ESEM and XPS to enamel dissolution studies are also reported. The individual effects of DSHA, pH and calcium and phosphate concentrations on enamel dissolution have been investigated. It was shown that there exists a threshold condition defined by calcium and phosphate concentrations and pH, below which there is considerable dissolution and a rapid dependence of dissolution rate on DSHA, and above which little or no discernible dissolution takes place. This threshold condition corresponds to a considerably undersaturated solution (DSHA ≅ 0.1). However, contrary to assumptions in many enamel dissolution models in the literature, DSHA is not sufficient to predict the dissolution rate and the individual calcium and phosphate concentrations are also important. The dependence of enamel dissolution on pH is comparatively minor, with only a small change in dissolution rate for a change in pH. In terms of soft drink modification, it has been shown here that DSHA adjustment can be used to greatly reduce the rate of enamel dissolution, and that a concurrent change in pH may be superfluous. (author)

  16. Combined effects of independent variables on yield and protein content of pectin extracted from sugar beet pulp by citric acid.

    Science.gov (United States)

    Li, De-Qiang; Du, Guang-Ming; Jing, Wei-Wen; Li, Jun-Fang; Yan, Jia-Yu; Liu, Zhi-Yong

    2015-09-20

    The extraction of pectin from sugar beet pulp by citric acid was carried out under different conditions using Box-Behnken design for four independent variables (pH, temperature, time and liquid to solid ratio). The yield of sugar beet pulp pectin ranged from 6.3% to 23.0%, and the content of protein from 1.5% to 4.5%. All independent variables significantly affected the yield, and all variables except liquid to solid ratio significantly affected the protein content. The yield increased as decreasing pH of extracting solution, extending time and advancing temperature, and an opposite relationship of effects between variables and content of protein was obtained. The chemical composition of collected samples was determined. Moreover, from the results of emulsifying properties study, the extracted pectin from sugar beet pulp could prepare steady oil-in-water emulsions. Therefore, it was inferred that the extraction conditions could influence yield and protein content, resulting in different emulsifying property. PMID:26050895

  17. Enhancing the reactivity of bimetallic Bi/Fe(0) by citric acid for remediation of polluted water.

    Science.gov (United States)

    Gong, Jianyu; Lee, Chung-Seop; Kim, Eun-Ju; Chang, Yoon-Young; Chang, Yoon-Seok

    2016-06-01

    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(0)). The characterization results revealed the existence of bismuth covering on the Fe(0) surface under zero-valent state. And, the Bi/Fe(0)-CA+O2 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 30min of reaction, 80% of 4-CP was removed using Bi/Fe(0)-CA+O2 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(3+) to form a ligand complex (Fe(III)Cit), accompanying with a considerable production of Fe(2+) and H2O2. This study provides a new strategy for generating ROS on nZVI and suggests its application for the mineralization of many recalcitrant pollutants. PMID:26905611

  18. Antitussive Activity of the Water-Extracted Carbohydrate Polymer from Terminalia chebula on Citric Acid-Induced Cough

    Science.gov (United States)

    Chatterjee, Udipta Ranjan; Majee, Sujay Kumar; Ray, Bimalendu

    2013-01-01

    Terminalia chebula, a medicinal plant, is widely used in the management of various diseases. As the water extract of its dried ripe fruit is a frequently used preparation, we decided to look for bioactive polysaccharide in this extract. We demonstrate that the obtained polysaccharide fraction, CP, contained a highly branched arabinogalactan protein having a (1 → 3)-, (1 → 6)- and (1 → 3, 6)-linked β-D-Galp together with (1 → 5)- and (1 → 3)-linked α-L-Araf and nonreducing end units of α-L-Araf. This polymer possesses strong antitussive property. Our results showed that the number of citric acid-induced cough efforts decreased significantly after the oral application of polysaccharide fraction in a dose of 50 mg kg−1 body weight. Its antitussive efficacy was higher than cough suppressive effect of standard drug codeine. Therefore, traditional aqueous extraction method provides a major polysaccharide, which induces a pharmacological effect: this could represent an attractive approach in phytotherapeutic managements. PMID:23878602

  19. Antitussive Activity of the Water-Extracted Carbohydrate Polymer from Terminalia chebula on Citric Acid-Induced Cough

    Directory of Open Access Journals (Sweden)

    Gabriela Nosalova

    2013-01-01

    Full Text Available Terminalia chebula, a medicinal plant, is widely used in the management of various diseases. As the water extract of its dried ripe fruit is a frequently used preparation, we decided to look for bioactive polysaccharide in this extract. We demonstrate that the obtained polysaccharide fraction, CP, contained a highly branched arabinogalactan protein having a 1→3-, 1→6- and 1→3,6-linked β-D-Galp together with 1→5- and 1→3-linked α-L-Araf and nonreducing end units of α-L-Araf. This polymer possesses strong antitussive property. Our results showed that the number of citric acid-induced cough efforts decreased significantly after the oral application of polysaccharide fraction in a dose of 50 mg kg−1 body weight. Its antitussive efficacy was higher than cough suppressive effect of standard drug codeine. Therefore, traditional aqueous extraction method provides a major polysaccharide, which induces a pharmacological effect: this could represent an attractive approach in phytotherapeutic managements.

  20. Determining soil enzyme activities for the assessment of fungi and citric acid-assisted phytoextraction under cadmium and lead contamination.

    Science.gov (United States)

    Mao, Liang; Tang, Dong; Feng, Haiwei; Gao, Yang; Zhou, Pei; Xu, Lurong; Wang, Lumei

    2015-12-01

    Microorganism or chelate-assisted phytoextraction is an effective remediation tool for heavy metal polluted soil, but investigations into its impact on soil microbial activity are rarely reported. Consequently, cadmium (Cd)- and lead (Pb)-resistant fungi and citric acid (CA) were introduced to enhance phytoextraction by Solanum nigrum L. under varied Cd and Pb pollution levels in a greenhouse pot experiment. We then determined accumulation of Cd and Pb in S. nigrum and the soil enzyme activities of dehydrogenase, phosphatase, urease, catalase, sucrase, and amylase. Detrended canonical correspondence analysis (DCCA) was applied to assess the interactions between remediation strategies and soil enzyme activities. Results indicated that the addition of fungi, CA, or their combination enhanced the root biomass of S. nigrum, especially at the high-pollution level. The combined treatment of CA and fungi enhanced accumulation of Cd about 22-47 % and of Pb about 13-105 % in S. nigrum compared with the phytoextraction alone. However, S. nigrum was not shown to be a hyperaccumulator for Pb. Most enzyme activities were enhanced after remediation. The DCCA ordination graph showed increasing enzyme activity improvement by remediation in the order of phosphatase, amylase, catalase, dehydrogenase, and urease. Responses of soil enzyme activities were similar for both the addition of fungi and that of CA. In summary, results suggest that fungi and CA-assisted phytoextraction is a promising approach to restoring heavy metal polluted soil. PMID:26286803

  1. Fabrication and characterization of elastomeric scaffolds comprised of a citric acid-based polyester/hydroxyapatite microcomposite

    International Nuclear Information System (INIS)

    Highlights: • Porous scaffolds were prepared from polymer/hydroxyapatite (POC/HA) composite. • The pore size was designed to be uniform for all POC/HA composite scaffolds. • Compression strength and modulus are dependent on HA concentration within composite. - Abstract: In this paper we describe an effective technical route for the production of porous scaffolds from microcomposite material consistent of citric acid-based polyester elastomer and hydroxyapatite microparticles with potential use in tissue engineering applications. Fabricated scaffolds were characterized by field emission electron microscopy, Fourier-transform infra-red spectroscopy, thermal gravimetric analysis and mechanical tests. We demonstrate that the chemical composition, scaffold morphology, mechanical integrity and porosity of the produced microcomposite scaffolds are strongly affected by variation of the initial hydroxyapatite concentration in the mineral-polymer mixture during the fabrication process. This polyester/mineral scaffold exhibits versatility in compression modulus and strength in the range of 21.72–33.25 KPa and 49.92–101.48 KPa respectively, corresponding to the hydroxyapatite concentration in the composite (10–30 wt.%)

  2. Research advance of determination methods of citric acids in food%食品中柠檬酸的检测方法研究进展

    Institute of Scientific and Technical Information of China (English)

    张素娟

    2011-01-01

    According to advances of home, this paper discussed measure methods of citric acids in food. The common methods for citric acids were introduced as emphasis,such as high performance liquid chromatography ( HPLC), ion chromatography( IC), gas chromatography( GC ), electrophoresis, infrared absorption spectrometry.Finally,it suggested that the effective methods determined should be adopted.%结合国内的研究进展,综述了食品中柠檬酸的各种检测方法.其中重点介绍了比较常用的测定方法,如高效液相色谱法、离子色谱法、气相色谱法、电泳法、分光光度法等,并建议采取有效方法进行检测.

  3. Ultrafine nanoporous palladium-aluminum film fabricated by citric acid-assisted hot-water-treatment of aluminum-palladium alloy film

    OpenAIRE

    Takashi Harumoto; Yohei Tamura; Takashi Ishiguro

    2015-01-01

    Hot-water-treatment has been adapted to fabricate ultrafine nanoporous palladium-aluminum film from aluminum-palladium alloy film. Using citric acid as a chelating agent, a precipitation of boehmite (aluminum oxide hydroxide, AlOOH) on the nanoporous palladium-aluminum film was suppressed. According to cross-sectional scanning transmission electron microscopy observations, the ligament/pore sizes of the prepared nanoporous film were considerably small (on the order of 10 nm). Since this fabri...

  4. Investigation of the Effects of Solution Temperature on the Corrosion Behavior of Austenitic Low-Nickel Stainless Steels in Citric Acid using Impedance and Polarization Measurements

    OpenAIRE

    Mulimbayan Francis M.; Mena Manolo G.

    2015-01-01

    Stainless steels may be classified according to alloy microstructure – ferritic, austenitic, martensitic, duplex, and precipitation hardening grades. Among these, austenitic grade has the largest contribution to market due to the alloy’s numerous industrial and domestic applications. In this study, the corrosion behavior of low-Nickel stainless steel in citric acid was investigated using potentiodynamic polarization techniques and Electrochemical Impedance Spectroscopy (EIS). The corrosion cu...

  5. Effect of citric acid on formation of oxides of Cu and Zn in modified sol-gel process: A comparative study

    Indian Academy of Sciences (India)

    KAMARAJ MAHENDRAPRABHU; PERUMAL ELUMALAI

    2016-05-01

    We report here the influence of citric acid concentration on the formation of sol-gel products ineach of Cu and Zn systems by using respective metal nitrate as precursor and citric acid as gelling agent. Thesynthesized sol-gel products were characterized by X-ray diffraction (XRD), scanning electron microscope(SEM), energy dispersive X-ray analysis (EDX), Fourier transform infra-red (FT-IR) spectroscopy and UVVisiblediffused reflectance spectroscopy (UV-Vis DRS). The influence of citric acid concentration on theformation of metal/metal oxide in each case was primarily investigated by varying the molar ratio of each metalnitrate (N) and citric (C) acid (N:C = 1:1, 1:2, 1:4, 1:6 and 1:8). It was observed that at low N:C molar ratios(1:1) and (1:2), the Cu system had only CuO and at high N:C molar ratio, lower oxidation state of copper(Cu2O and Cu) has resulted. Distinctly, irrespective of the N:C molar ratio, the sol-gel product of Zn systemwas only single phase of ZnO. The SEM observations confirmed that the grains of these two metal systemswere spherical in nature. In each metal system, at high N:C molar ratio, small grain size has resulted. At highN:C ratio, lower oxidation state of metal ion is resulted where the metal system is susceptible for reduction. Thesusceptibility of metal ions to undergo reduction controlled the formation of end products in the sol-gel process.

  6. Calculation of the Aqueous Thermodynamic Properties of Citric Acid Cycle Intermediates and Precursors and the Estimation of High Temperature and Pressure Equation of State Parameters

    OpenAIRE

    Mitchell Schulte; Peter Dalla-Betta

    2009-01-01

    The citric acid cycle (CAC) is the central pathway of energy transfer for many organisms, and understanding the origin of this pathway may provide insight into the origins of metabolism. In order to assess the thermodynamics of this key pathway for microorganisms that inhabit a wide variety of environments, especially those found in high temperature environments, we have calculated the properties and parameters for the revised Helgeson-Kirkham-Flowers equation of state for the major component...

  7. The effect of citric acid on morphology and photoluminescence properties of white light emitting ZnO-SiO2 nanocomposites

    Science.gov (United States)

    Sivakami, R.; Thiyagarajan, P.

    2016-07-01

    The white light emitting ZnO-SiO2 nanocomposites were synthesized by sol-gel combustion method using zinc nitrate, citric acid and tetraethoxysilane. To analyze the effect of fuel content on the photoluminescence properties of ZnO-SiO2 nanocomposites, the citric acid content was varied as 1, 5, and 10 moles with respect to one mole of zinc. The SEM images of the nanocomposites revealed the spherical, flower and platelet like morphology with variation in citric acid content and annealing temperatures. The ZnO-SiO2 nanocomposites prepared with various Zn:CA ratio excited at UV (280 nm), near UV (365 nm), violet (405 nm) and blue (465 nm) wavelength showed blue and greenish-yellow emission. Among all ratios, the ZnO-SiO2 nanocomposites with Zn:CA - 1:1 ratio showed the intense broad band emission compared to Zn:CA - 1:5 and 1:10 values. This particular composition of sample excited under violet (405 nm) LED source shows white light, as confirmed by the CIE chromaticity coordinates (x = 0.342, y = 0.318).

  8. Investigation of the Effects of Solution Temperature on the Corrosion Behavior of Austenitic Low-Nickel Stainless Steels in Citric Acid using Impedance and Polarization Measurements

    Directory of Open Access Journals (Sweden)

    Mulimbayan Francis M.

    2015-01-01

    Full Text Available Stainless steels may be classified according to alloy microstructure – ferritic, austenitic, martensitic, duplex, and precipitation hardening grades. Among these, austenitic grade has the largest contribution to market due to the alloy’s numerous industrial and domestic applications. In this study, the corrosion behavior of low-Nickel stainless steel in citric acid was investigated using potentiodynamic polarization techniques and Electrochemical Impedance Spectroscopy (EIS. The corrosion current density which is directly related to corrosion rate was extracted from the generated anodic polarization curve. Increasing the temperature of the citric acid resulted to increased corrosion current densities indicating higher corrosion rates at initial corrosion condition. EIS was performed to generate Nyquist plots whose shape and size depicts the corrosion mechanism and corrosion resistance of the alloy in citric acid, respectively. All the generated Nyquist plots have depressed semi-circle shapes implying that corrosion process takes place with charge-transfer as the rate-determining step. Based from the extracted values of polarization resistance (Rp, the temperature of the solution has negative correlation with the corrosion resistance of the studied alloy.

  9. The Mechanism of Sol-Gel Synthesis of Normal Spinel LiMn2O4 with Chelation of Citric Acid

    Institute of Scientific and Technical Information of China (English)

    WU Hui; LEI Jia-heng; CHEN Yong-xi; SUN Yu-bin; YUAN Qi-hua

    2002-01-01

    The sol-gel process of citric acid chelating with metal cations for the synthesis of normal spinel LiMn2O4 and the reaction mechanism were investigated by means of XRD, IR, TG-DTA, and SEM. The results show that at the beginning lithium citrate and chelate compound of citric acid with manganese ions formed, and then with heating the esterification and condensation reactions occured between them and glycol. The products obtained are polymers in which metal cations are distributed homogeneously on atomic scale that ensure high reactivity to cations of Li + and Mn2 + . Firing the gel prepared by this process, the lattice diffusions of solid reactant ions caused by non-homogeneity of reactants are eliminated and avoided. At 400℃ phase-pure LiMn2 O4 with nanometer scale crystallization having precise stoichiometry and perfect crystallization can be obtained. The model of chelate coordinate of double-molecule between citric acid and Mn2 + in the gel network is proposed. It is important for explaining the dispersion state of Mn2 + and the formation process of gel by this model.

  10. Fabrication of Sn-3.5Ag Eutectic Alloy Powder by Annealing Sub-Micrometer Sn@Ag Powder Prepared by Citric Acid-Assisted Ag Immersion Plating.

    Science.gov (United States)

    Chee, Sang-Soo; Choi, Eun Byeol; Lee, Jong-Hyun

    2015-11-01

    A Sn-3.5Ag eutectic alloy powder has been developed by chemically synthesizing sub-micrometer Sn@Ag powder at room temperature. This synthesis was achieved by first obtaining a sub-micrometer Sn powder for the core using a modified variant of the polyol method, and then coating this with a uniformly thin and continuous Ag layer through immersion plating in 5.20 mM citric acid. The citric acid was found to play multiple roles in the Ag coating process, acting as a chelating agent, a reducing agent and a stabilizer to ensure coating uniformity; and as such, the amount used has an immense influence on the coating quality of the Ag shells. It was later verified by transmission electron microscopy and X-ray diffraction analysis that the coated Ag layer transfers to the Sn core via diffusion to form an Ag3Sn phase at room temperature. Differential scanning calorimetry also revealed that the synthesized Sn@Ag powder is nearly transformed into Sn-3.5Ag eutectic alloy powder upon annealing three times at a temperature of up to 250 degrees C, as evidenced by a single melting peak at 220.5 degrees C. It was inferred from this that Sn-3.5Ag eutectic alloy powder can be successfully prepared through the synthesis of core Sn powders by a modified polyol method, immersion plating using citric acid, and annealing, in that order. PMID:26726525

  11. Effect of Molar Ratio of Citric Acid to Metal Nitrate on the Structure and Catalytic Activity of NiO Nanoparticles

    Institute of Scientific and Technical Information of China (English)

    WU Gang; TAN Xiao-yan; LI Gui-ying; HU Chang-wei

    2013-01-01

    NiO nanoparticles were prepared by means of sol-gel method via varying the ratio of citric acid to nickel nitrate.The samples were characterized by powder X-ray diffraction(XRD),Fourier transform infrared(FTIR) spectroscopy,transmission electron microscopy(TEM) and X-ray photoelectron spectroscopy(XPS).It was found that the molar ratio of citric acid to nickel nitrate has a great effect on the crystal structure and particle size of NiO.The increase of the molar ratio of citric acid to nickel nitrate is favorable to the formation of NiO smaller particles within the range tested.Compared to bulk NiO obtained by thermal decomposition,NiO nanoparticles possess more surface oxygen species O-.The activity test indicates that surface oxygen species O-plays a crucial role in the hydroxylation of benzene to phenol with hydrogen peroxide as oxidant.The active site may be originated from Ni2+ on the surface of the samples,while Ni0 does not contribute to the hydroxylation reaction.

  12. The use of ultrasound and infrared radiation to reduce microbiological contamination of raw materials in the production of citric acid

    International Nuclear Information System (INIS)

    The microflora of the main raw materials for producing citric acid (beet molasses and grain) is capable of greatly reducing the yield of target metabolite or changing the focus of biosynthesis. Rye, oats and barley grain with humidity of 16% and its grinds (a particle size 1 mm) was treated ultrasound having a capacity of 1.5 kW, frequency 15 and 22 kHz. Infrared radiation treatment was carried out at t 120 to 180 degrees C for 2-30 min and the exposure power W/sq. cm. In molasses there were found spore-forming heat-resistant bacteria with Bacillus subtilis and B. mesentericus being predominated, gaseous, nitrite-forming, acid-forming bacteria, yeast of gen. Candida, Leuconostoc mesenteroides that consume sugar, nitric and mineral substances reducing the biosynthetic activity of Aspergillus niger producer. For molasses treated with ultrasound 1.5 kW and frequency 22 kHz, the total viable count reduces by the order compared to the control. Increasing the exposure time up to 30 min results in slightly reducing the achieved level. Under influence of ultrasound the contamination with bacteria and mold fungi of rye, oats and barley grain grinds reduces by 2-3 orders compared to the control and much more at frequency 22 kHz. The great increase in the parameter of the total viable count is achieved by IR-treatment of grain and grinds. The microflora practically entirely dies by increasing the temperature up to 160-180 degrees C even in case of 2 minute exposure. IR treatment providing t 120 degrees C for 2-6 min resulted in reducing the number of cells of microorganisms by 3-4 orders compared to the untreated control

  13. The relation of high fat diet, metabolic disturbances and brain oxidative dysfunction: modulation by hydroxy citric acid

    Directory of Open Access Journals (Sweden)

    Kamel Hamdy H

    2011-05-01

    Full Text Available Abstract Aims This study aimed to examine the effect of high fat diet (HFD to modulate brain dysfunction, and understand the linkages between obesity, metabolic disturbances and the brain oxidative stress (BOS dysfunction and modulation with hydroxyl citric acid of G. Cambogia. Methods Rats were divided into 3 groups; 1st control, maintained on standard normal rat chow diet, 2nd HFD, maintained on high fat diet along 12 week and 3rd HFD+G, administered G. Cambogia for 4 weeks and each group include 8 rats. Blood, brain and abdominal fat were collected for biochemical measurements. Results HFD group showed significant increase in energy intake, final BW and BW gain. Also significant increase in weight of abdominal fat in HFD group. HFD induce metabolic disturbance through increasing the lipid profile (LDL, TG, TC, γGT and α-amylase activity, uric acid level and hyperglycemia, while decreasing creatine kinase (CK activity. These changes associated with lowering in brain nitric oxide (NO level and rising in serum butyrylcholinesterase (BChE, brain catalase activity and MDA levels as oxidative stress markers. These alterations improved by G. Cambogia that decrease BOS and increased NO level. Conclusions Rats fed HFD showed, metabolic disturbances produce hyperglycemia, hypertriglyceridemia, hypercholesterolemia and increased LDL associated with increased BOS. Involvement of BuChE, NO and oxidative stress associated with metabolic disturbances in the pathophysiological progression in brain, suggesting association between obesity, metabolic disorders and brain alteration while, using G. Cambogia, ameliorate the damaging effects of the HFD via lowering feed intake and BOS.

  14. A comparative study of the antitussive activity of levodropropizine and dropropizine in the citric acid-induced cough model in normal subjects.

    Science.gov (United States)

    Fumagalli, G; Cordaro, C I; Vanasia, M; Balzarotti, C; Camusso, L; Caiazzo, G; Maghini, L; Mazzocchi, M; Zennaro, M

    1992-01-01

    Levodropropizine is the levo-rotatory (S)-enantiomer of dropropizine, a racemic non-opiate antitussive agent which has been used clinically for many years. Compared with the racemic drug, levodropropizine exhibits in animal models similar antitussive activity but considerably lower central nervous system (CNS) depressant effects. It is also less likely to cause sedation in treated patients. Since the comparative antitussive potency of the two drugs in clinical experimental models has not been evaluated, the authors performed a randomized, double blind, cross over investigation in which the effects of single oral doses (60 and 90 mg) of levodropropizine and dropropizine were assessed by using the citric acid-induced cough model in eight normal volunteers. Stimulation tests involved inhalation of individual cumulative doses of citric acid (6.3 to 53.3 mg) which at pre-study assessment had been found to induce reproducibly at least ten coughs over a 30 sec period. Each subject was studied by repeating the citric acid stimulation test four times (0 h, 1 h, 2 h and 6 h) on each of five different days separated by intervals of at least three days. In the absence of drug administration (control session), cough response to citric inhalation was remarkably reproducible throughout the 6 h period of observation. A marked and statistically significant reduction in cough response (to about one third--one sixth of the pre-drug values) was observed 1 h after intake for both compounds. At subsequent testing 2 h and 6 h after dosing, cough response was still depressed and did not differ significantly from that observed at 1 h.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1295724

  15. The production and use of citric acid for the removal of potassium from the iron ore concentrate of the Sishen Iron Ore Mine, South Africa

    Directory of Open Access Journals (Sweden)

    Peter J. Williams

    2010-04-01

    Full Text Available The depletion of the richer iron ore worldwide has made it necessary to process lower quality iron ore. Certain substances, such as potassium, contained within the lower quality iron ore, have a detrimental effect on the smelting process during steel manufacturing. Therefore, international steel-making companies charge penalties when purchasing iron ore concentrates containing high concentrations of potassium. To date, lower quality iron ore has been blended with high quality iron ore in an attempt to alleviate the potassium concentrations in the export iron ore; however, the ratio of low quality iron ore to high quality iron ore is increasing, thereby becoming an escalating problem within the economic functioning of the Sishen Iron Ore Mine. It has, therefore, become necessary to develop an economically viable and environmentally friendly process to reduce the high potassium concentrations contained in the iron ore concentrate of the Sishen Iron Ore Mine. In this study, we compared solid substrate and submerged fermentation using Aspergillus niger for the production of citric acid, which is used for the chemical leaching of potassium from the iron ore concentrate. It was found that submerged fermentation proved to be more economical and efficient, producing a maximum citric acid concentration of 102.3 g/L in 96 h of fermentation. ‘Heap leaching’ simulation experiments were found to be uneconomical, due to the required addition of fungal growth medium every 5 days as a result of growth factor depletion within this time; however, this process removed 17.65% of the potassium from the iron ore concentrate. By contrast, chemical leaching of potassium from the iron ore concentrate proved to be most efficient when using a 1 mol citric acid leaching solution at 60 ºC, removing 23.53% of the potassium contained within the iron ore concentrate. Therefore, the most economical and efficient process for the removal of potassium from the iron

  16. Scalable Fabrication of Electrospun Nanofibrous Membranes Functionalized with Citric Acid for High-Performance Protein Adsorption.

    Science.gov (United States)

    Fu, Qiuxia; Wang, Xueqin; Si, Yang; Liu, Lifang; Yu, Jianyong; Ding, Bin

    2016-05-11

    Fabricating protein adsorbents with high adsorption capacity and appreciable throughput is extremely important and highly desired for the separation and purification of protein products in the biomedical and pharmaceutical industries, yet still remains a great challenge. Herein, we demonstrate the synthesis of a novel protein adsorbent by in situ functionalizing eletrospun ethylene-vinyl alcohol (EVOH) nanofibrous membranes (NFM) with critic acid (CCA). Taking advantage of the merits of large specific surface area, highly tortuous open-porous structure, abundant active carboxyl groups introduced by CCA, superior chemical stability, and robust mechanical strength, the obtained CCA-grafted EVOH NFM (EVOH-CCA NFM) present an excellent integrated protein (take lysozyme as the model protein) adsorption performance with a high capacity of 284 mg g(-1), short equilibrium time of 6 h, ease of elution, and good reusability. Meanwhile, the adsorption performance of EVOH-CCA NFM can be optimized by regulating buffer pH, ionic strength, and initial concentration of protein solutions. More importantly, a dynamic binding efficiency of 250 mg g(-1) can be achieved driven solely by the gravity of protein solution, which matches well with the demands of the high yield and energy conservation in the actual protein purification process. Furthermore, the resultant EVOH-CCA NFM also possess unique selectivity for positively charged proteins which was confirmed by the method of sodium dodecyl sulfate polyacrylamide gel electrophoresis. Significantly, the successful synthesis of such intriguing and economic EVOH-CCA NFM may provide a promising candidate for the next generation of protein adsorbents for rapid, massive, and cost-effective separation and purification of proteins. PMID:27111287

  17. Retention Mechanisms of Citric Acid in Ternary Kaolinite-Fe(III)-Citrate Acid Systems Using Fe K-edge EXAFS and L3,2-edge XANES Spectroscopy

    Science.gov (United States)

    Yang, Jianjun; Wang, Jian; Pan, Weinan; Regier, Tom; Hu, Yongfeng; Rumpel, Cornelia; Bolan, Nanthi; Sparks, Donald

    2016-05-01

    Organic carbon (OC) stability in tropical soils is strongly interlinked with multivalent cation interaction and mineral association. Low molecular weight organic acids (LMWOAs) represent the readily biodegradable OC. Therefore, investigating retention mechanisms of LMWOAs in mineral-cation-LMWOAs systems is critical to understanding soil C cycling. Given the general acidic conditions and dominance of kaolinite in tropical soils, we investigated the retention mechanisms of citric acid (CA) in kaolinite-Fe(III)-CA systems with various Fe/CA molar ratios at pH ~3.5 using Fe K-edge EXAFS and L3,2-edge XANES techniques. With Fe/CA molar ratios >2, the formed ferrihydrite mainly contributed to CA retention through adsorption and/or coprecipitation. With Fe/CA molar ratios from 2 to 0.5, ternary complexation of CA to kaolinite via a five-coordinated Fe(III) bridge retained higher CA than ferrihydrite-induced adsorption and/or coprecipitation. With Fe/CA molar ratios ≤0.5, kaolinite-Fe(III)-citrate complexation preferentially occurred, but less CA was retained than via outer-sphere kaolinite-CA complexation. This study highlighted the significant impact of varied Fe/CA molar ratios on CA retention mechanisms in kaolinite-Fe(III)-CA systems under acidic conditions, and clearly showed the important contribution of Fe-bridged ternary complexation on CA retention. These findings will enhance our understanding of the dynamics of CA and other LMWOAs in tropical soils.

  18. Structure elucidation and quantification of impurities formed between 6-aminocaproic acid and the excipients citric acid and sorbitol in an oral solution using high-resolution mass spectrometry and nuclear magnetic resonance spectroscopy

    DEFF Research Database (Denmark)

    Schou-Pedersen, Anne Marie V; Cornett, Claus; Nyberg, Nils; Østergaard, Jesper; Hansen, Steen Honoré

    Concentrated solutions containing 6-aminocaproic acid and the excipients citric acid and sorbitol have been studied at temperatures of 50°C, 60°C, 70°C and 80°C as well as at 20°C. It has previously been reported that the commonly employed citric acid is a reactive excipient, and it is therefore...... cyclized 6-aminocaproic acid, i.e., caprolactam. No reaction products between d-sorbitol and 6-aminocaproic acid could be observed. 3-Hydroxy-3,4-dicarboxy-butanamide-N-hexanoic acid, dimer and caprolactam were also observed after storage at 20°C for 3 months. The findings imply that an oral solution of 6...

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

    OpenAIRE

    Lu, Ling-li; Tian, Sheng-ke; Yang, Xiao-e; Peng, Hong-yun; Li, Ting-qiang

    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-t...

  20. Speciation of U(VI) sorbed onto ZrP2O7 in the presence of citric and oxalic acid

    International Nuclear Information System (INIS)

    In the field of nuclear waste management, prediction of radionuclide migration through the geosphere has to take into account the effects of organic matter. This work deals with the effects of organic acids (citric and oxalic acid) on speciation of uranium(VI) sorbed onto zirconium diphosphate (ZrP2O7). Surface properties of zirconium diphosphate and its uranium(VI) sorption capability in the presence and absence of organic acids were previously studied. The preliminary study suggested that organic acids take part in the sorption equilibria. In order to understand the interactions between organic ligands (citrate or oxalate), uranium(VI) and zirconium diphosphate, a luminescence spectroscopy study was carried out. Luminescence measurements indicated that only one uranium(VI) surface complex is formed when citric or oxalic acid is present. Moreover, the total carbon content in the studied samples indicated that organic ligands remain on the surface when uranium(VI) sorption is carried out. Uranium sorption edges were then fitted with the FITEQL4.0 code [15] and the constant capacitance model (CCM). Spectroscopy information was used to constraint the modeling. The best fit for the U(VI)/citrate/ZrP2O7 and U(VI)/oxalate/ZrP2O7 systems considered the formation of a ternary surface complex. (orig.)

  1. Speciation of U(VI) sorbed onto ZrP{sub 2}O{sub 7} in the presence of citric and oxalic acid

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Gonzalez, N. [Instituto Nacional de Investigaciones Nucleares, Mexico City (Mexico); Universidad Autonoma del Estado de Mexico, Toluca (Mexico). Facultad de Quimica; Ordonez-Regil, E.; Almazan-Torres, M.G. [Instituto Nacional de Investigaciones Nucleares, Mexico City (Mexico); Solis, D. [Universidad Autonoma del Estado de Mexico, Toluca (Mexico). Facultad de Quimica; Simoni, E. [Paris-Sud 11 Univ., 91 - Orsay (France). Inst. de Physique Nucleaire, CNRS, IN2P3

    2012-07-01

    In the field of nuclear waste management, prediction of radionuclide migration through the geosphere has to take into account the effects of organic matter. This work deals with the effects of organic acids (citric and oxalic acid) on speciation of uranium(VI) sorbed onto zirconium diphosphate (ZrP{sub 2}O{sub 7}). Surface properties of zirconium diphosphate and its uranium(VI) sorption capability in the presence and absence of organic acids were previously studied. The preliminary study suggested that organic acids take part in the sorption equilibria. In order to understand the interactions between organic ligands (citrate or oxalate), uranium(VI) and zirconium diphosphate, a luminescence spectroscopy study was carried out. Luminescence measurements indicated that only one uranium(VI) surface complex is formed when citric or oxalic acid is present. Moreover, the total carbon content in the studied samples indicated that organic ligands remain on the surface when uranium(VI) sorption is carried out. Uranium sorption edges were then fitted with the FITEQL4.0 code [15] and the constant capacitance model (CCM). Spectroscopy information was used to constraint the modeling. The best fit for the U(VI)/citrate/ZrP{sub 2}O{sub 7} and U(VI)/oxalate/ZrP{sub 2}O{sub 7} systems considered the formation of a ternary surface complex. (orig.)

  2. Heavy metal removal from sludge with organic chelators: Comparative study of N, N-bis(carboxymethyl) glutamic acid and citric acid.

    Science.gov (United States)

    Suanon, Fidèle; Sun, Qian; Dimon, Biaou; Mama, Daouda; Yu, Chang-Ping

    2016-01-15

    The applicability and performance of a new generation of biodegradable chelator, N, N-Bis(carboxymethyl) glutamic acid (GLDA), for extracting heavy metals from sewage sludge was carried out and compared with citric acid (CA). Targeted metals included Cd, Co, Cu, Zn, Ni and Cr, and their contents in the raw sludge were 63.1, 73.4, 1103.2, 2060.3, 483.9 and 604.1 mg kg(-1) (dry sludge basis), respectively. Metals were divided into six fractions including water soluble, exchangeable, carbonates bound, Fe-Mn bound, organic matters bound and residual fraction via chemical fractionation. Washing results showed that in general GLDA exhibited better performance compared with CA, with removal efficiency of 83.9, 87.3, 81.2, 85.6, 89.3 and 90.2% for Cd, Co, Cu, Zn, Ni and Cr, respectively at equilibrium pH = 3.3. Residual metals were better stabilized in the GLAD-washed sludge than in the CA-washed sludge, and were mostly tightly bonded to the residual fraction. Furthermore, CA promoted phosphorus (P) release while GLDA had an opposite effect and tended to retain P within sludge, which could be beneficial for further application in agricultural use. Findings from this study suggested that GLDA could be a potential replacement for refractory and less environmentally-friendly chelators in the extraction of metals from sludge. PMID:26520041

  3. Collagen based film with well epithelial and stromal regeneration as corneal repair materials: Improving mechanical property by crosslinking with citric acid

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Xuan; Liu, Yang; Li, Weichang; Long, Kai; Wang, Lin; Liu, Sa; Wang, Yingjun [School of Materials Science and Engineering, South China University of Technology, Guangzhou (China); National Engineering Research Center for Tissue Restoration and Reconstruction, Guangzhou (China); Ren, Li, E-mail: psliren@scut.edu.cn [School of Materials Science and Engineering, South China University of Technology, Guangzhou (China); National Engineering Research Center for Tissue Restoration and Reconstruction, Guangzhou (China)

    2015-10-01

    Corneal disease can lead to vision loss. It has become the second greatest cause of blindness in the world, and keratoplasty is considered as an effective treatment method. This paper presents the crosslinked collagen (Col)–citric acid (CA) films developed by making use of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS). The results showed that the Col–CA films had necessary optical performance, water content. The collagenase resistance of CA crosslinked films was superior to that of EDC crosslinked films. And CA5 film (Col:CA:EDC:NHS = 60:3:10:10) had the best mechanical properties. Cell experiments showed that CA5 film was non-cytotoxic and human corneal epithelial cells could proliferate well on the films. Lamellar keratoplasty showed that the CA5 film could be sutured in the rabbit eyes and was epithelialized completely in about 10 days, and the transparency was restored quickly in 30 ± 5 days. No inflammation and corneal neovascularization were observed at 6 months. Corneal stroma had been repaired; stromal cells and neo-stroma could be seen in the area of operation from the hematoxylin–eosin stained histologic sections and anterior segment optical coherence tomography images. These results indicated that Col–CA films were highly promising biomaterials that could be used in corneal tissue engineering and a variety of other tissue engineering applications. - Highlights: • Adding different amounts of citric acid could change the properties of films. • The crosslinked films had better mechanical property than non-modified films. • Crosslinked collagen–citric acid films could tolerate suture during operation. • The films showed good ability of epithelial and stromal repair.

  4. Optimization of ethanol, citric acid, and α-amylase production from date wastes by strains of Saccharomyces cerevisiae, Aspergillus niger, and Candida guilliermondii.

    Science.gov (United States)

    Acourene, S; Ammouche, A

    2012-05-01

    The present study deals with submerged ethanol, citric acid, and α-amylase fermentation by Saccharomyces cerevisiae SDB, Aspergillus niger ANSS-B5, and Candida guilliermondii CGL-A10, using date wastes as the basal fermentation medium. The physical and chemical parameters influencing the production of these metabolites were optimized. As for the ethanol production, the optimum yield obtained was 136.00 ± 0.66 g/l under optimum conditions of an incubation period of 72 h, inoculum content of 4% (w/v), sugars concentration of 180.0 g/l, and ammonium phosphate concentration of 1.0 g/l. Concerning citric acid production, the cumulative effect of temperature (30°C), sugars concentration of 150.0 g/l, methanol concentration of 3.0%, initial pH of 3.5, ammonium nitrate concentration of 2.5 g/l, and potassium phosphate concentration of 2.5 g/l during the fermentation process of date wastes syrup did increase the citric acid production to 98.42 ± 1.41 g/l. For the production of α-amylase, the obtained result shows that the presence of starch strongly induces the production of α-amylase with a maximum at 5.0 g/l. Among the various nitrogen sources tested, urea at 5.0 g/l gave the maximum biomass and α-amylase estimated at 5.76 ± 0.56 g/l and 2,304.19 ± 31.08 μmol/l/min, respectively after 72 h incubation at 30°C, with an initial pH of 6.0 and potassium phosphate concentration of 6.0 g/l. PMID:22193823

  5. Synthesis of high intrinsic loss power aqueous ferrofluids of iron oxide nanoparticles by citric acid-assisted hydrothermal-reduction route

    Energy Technology Data Exchange (ETDEWEB)

    Behdadfar, Behshid, E-mail: bbehdadfar@ma.iut.ac.ir [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Kermanpur, Ahmad [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Sadeghi-Aliabadi, Hojjat [School of Pharmacy, Isfahan Pharmaceutical Research Center, Isfahan University of Medical Sciences, Isfahan (Iran, Islamic Republic of); Morales, Maria del Puerto [Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco 28049, Madrid (Spain); Mozaffari, Morteza [Department of Physics, Razi University, Kermanshah (Iran, Islamic Republic of)

    2012-03-15

    Monodispersed aqueous ferrofluids of iron oxide nanoparticle were synthesized by hydrothermal-reduction route. They were characterized by X-ray diffraction analysis, Fourier transform infrared spectroscopy, scanning and transmission electron microscopy and dynamic light scattering. The results showed that certain concentrations of citric acid (CA) are required to obtain only magnetic iron oxides with mean particle sizes around 8 nm. CA acts as a modulator and reducing agent in iron oxide formation which controls nanoparticle size. The XRD, magnetic and heating measurements showed that the temperature and time of hydrothermal reaction can affect the magnetic properties of obtained ferrofluids. The synthesized ferrofluids were stable at pH 7. Their mean hydrodynamic size was around 80 nm with polydispersity index (PDI) of 0.158. The calculated intrinsic loss power (ILP) was 9.4 nHm{sup 2}/kg. So this clean and cheap route is an efficient way to synthesize high ILP aqueous ferrofluids applicable in magnetic hyperthermia. - Graphical abstract: Monodispersed aqueous ferrofluids of iron oxide nanoparticles were synthesized by hydrothermal-reduction method with citric acid as reductant which is an efficient way to synthesize aqueous ferrofluids applicable in magnetic hyperthermia. Highlights: Black-Right-Pointing-Pointer Aqueous iron oxide ferrofluids were synthesized by hydrothermal-reduction route. Black-Right-Pointing-Pointer Citric acid acted as reducing agent and surfactant in the route. Black-Right-Pointing-Pointer This is a facile, low energy and environmental friendly route. Black-Right-Pointing-Pointer The aqueous iron oxide ferrofluids were monodispersed and stable at pH of 7. Black-Right-Pointing-Pointer The calculated intrinsic loss power of the synthesized ferrofluids was very high.

  6. Citric acid- and Tween(®) 80-assisted phytoremediation of a co-contaminated soil: alfalfa (Medicago sativa L.) performance and remediation potential.

    Science.gov (United States)

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

    2016-05-01

    A pot experiment was designed to assess the phytoremediation potential of alfalfa (Medicago sativa L.) in a co-contaminated (i.e., heavy metals and petroleum hydrocarbons) soil and the influence of citric acid and Tween(®) 80 (polyethylene glycol sorbitan monooleate), applied individually and combined together, for their possible use in chemically assisted phytoremediation. The results showed that alfalfa plants could tolerate and grow in a co-contaminated soil. Over a 90-day experimental time, shoot and root biomass increased and negligible plant mortality occurred. Heavy metals were uptaken by alfalfa to a limited extent, mostly by plant roots, and their concentration in plant tissues were in the following order: Zn > Cu > Pb. Microbial population (alkane-degrading microorganisms) and activity (lipase enzyme) were enhanced in the presence of alfalfa with rhizosphere effects of 9.1 and 1.5, respectively, after 90 days. Soil amendments did not significantly enhance plant metal concentration or total uptake. In contrast, the combination of citric acid and Tween(®) 80 significantly improved alkane-degrading microorganisms (2.4-fold increase) and lipase activity (5.3-fold increase) in the rhizosphere of amended plants, after 30 days of experiment. This evidence supports a favorable response of alfalfa in terms of tolerance to a co-contaminated soil and improvement of rhizosphere microbial number and activity, additionally enhanced by the joint application of citric acid and Tween(®) 80, which could be promising for future phytoremediation applications. PMID:26838038

  7. Collagen based film with well epithelial and stromal regeneration as corneal repair materials: Improving mechanical property by crosslinking with citric acid

    International Nuclear Information System (INIS)

    Corneal disease can lead to vision loss. It has become the second greatest cause of blindness in the world, and keratoplasty is considered as an effective treatment method. This paper presents the crosslinked collagen (Col)–citric acid (CA) films developed by making use of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS). The results showed that the Col–CA films had necessary optical performance, water content. The collagenase resistance of CA crosslinked films was superior to that of EDC crosslinked films. And CA5 film (Col:CA:EDC:NHS = 60:3:10:10) had the best mechanical properties. Cell experiments showed that CA5 film was non-cytotoxic and human corneal epithelial cells could proliferate well on the films. Lamellar keratoplasty showed that the CA5 film could be sutured in the rabbit eyes and was epithelialized completely in about 10 days, and the transparency was restored quickly in 30 ± 5 days. No inflammation and corneal neovascularization were observed at 6 months. Corneal stroma had been repaired; stromal cells and neo-stroma could be seen in the area of operation from the hematoxylin–eosin stained histologic sections and anterior segment optical coherence tomography images. These results indicated that Col–CA films were highly promising biomaterials that could be used in corneal tissue engineering and a variety of other tissue engineering applications. - Highlights: • Adding different amounts of citric acid could change the properties of films. • The crosslinked films had better mechanical property than non-modified films. • Crosslinked collagen–citric acid films could tolerate suture during operation. • The films showed good ability of epithelial and stromal repair

  8. Ultrafine nanoporous palladium-aluminum film fabricated by citric acid-assisted hot-water-treatment of aluminum-palladium alloy film

    International Nuclear Information System (INIS)

    Hot-water-treatment has been adapted to fabricate ultrafine nanoporous palladium-aluminum film from aluminum-palladium alloy film. Using citric acid as a chelating agent, a precipitation of boehmite (aluminum oxide hydroxide, AlOOH) on the nanoporous palladium-aluminum film was suppressed. According to cross-sectional scanning transmission electron microscopy observations, the ligament/pore sizes of the prepared nanoporous film were considerably small (on the order of 10 nm). Since this fabrication method only requires aluminum alloy film and hot-water with chelating agent, the ultrafine nanoporous film can be prepared simply and environmentally friendly

  9. Influence of citric acid solution as a test drink in the 14C-urea breath test for diagnosis of helicobactor pylori infection

    International Nuclear Information System (INIS)

    Different test meals are used in the 14C-urea breath test (UBT) for the detection of H.pylori infection. The purpose of using test meals is to slow gastric emptying and to maximise the distribution of the urea substrate within the stomach so as to increase the area and time of contact between bacteria and substrate. Recently, citric acid has been suggested as an improved liquid test meal. The mechanism is not known and could act by delaying gastric emptying, decreasing the pH at the site of the bacteria, or both

  10. Calculation of the Aqueous Thermodynamic Properties of Citric Acid Cycle Intermediates and Precursors and the Estimation of High Temperature and Pressure Equation of State Parameters

    Directory of Open Access Journals (Sweden)

    Mitchell Schulte

    2009-06-01

    Full Text Available The citric acid cycle (CAC is the central pathway of energy transfer for many organisms, and understanding the origin of this pathway may provide insight into the origins of metabolism. In order to assess the thermodynamics of this key pathway for microorganisms that inhabit a wide variety of environments, especially those found in high temperature environments, we have calculated the properties and parameters for the revised Helgeson-Kirkham-Flowers equation of state for the major components of the CAC. While a significant amount of data is not available for many of the constituents of this fundamental pathway, methods exist that allow estimation of these missing data.

  11. 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

    OpenAIRE

    Widayat Widayat; Abdullah Abdullah; H. Satriadi; M Hadi

    2011-01-01

    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% anti...

  12. The Unusual Acid-Accumulating Behavior during Ripening of Cherimoya (Annona cherimola Mill.) is Linked to Changes in Transcription and Enzyme Activity Related to Citric and Malic Acid Metabolism.

    Science.gov (United States)

    González-Agüero, Mauricio; Tejerina Pardo, Luis; Zamudio, María Sofía; Contreras, Carolina; Undurraga, Pedro; Defilippi, Bruno G

    2016-01-01

    Cherimoya (Annona cherimola Mill.) is a subtropical fruit characterized by a significant increase in organic acid levels during ripening, making it an interesting model for studying the relationship between acidity and fruit flavor. In this work, we focused on understanding the balance between the concentration of organic acids and the gene expression and activity of enzymes involved in the synthesis and degradation of these metabolites during the development and ripening of cherimoya cv. "Concha Lisa". Our results showed an early accumulation of citric acid and other changes associated with the accumulation of transcripts encoding citrate catabolism enzymes. During ripening, a 2-fold increase in malic acid and a 6-fold increase in citric acid were detected. By comparing the contents of these compounds with gene expression and enzymatic activity levels, we determined that cytoplasmic NAD-dependent malate dehydrogenase (cyNAD-MDH) and mitochondrial citrate synthase (mCS) play important regulatory roles in the malic and citric acid biosynthetic pathways. PMID:27120592

  13. Copper-catalyzed oxidation of a structured lipid-based emulsion containing alpha-tocopherol and citric acid: influence of pH and NaCl.

    Science.gov (United States)

    Osborn-Barnes, Hannah T; Akoh, Casimir C

    2003-11-01

    The effects of salt and pH on copper-catalyzed lipid oxidation in structured lipid-based emulsions were evaluated. Ten percent oil-in-water emulsions were formulated with a canola oil/caprylic acid structured lipid and stabilized with 0.5% whey protein isolate. alpha-Tocopherol and citric acid were added to the emulsions to determine how changes in pH or the addition of NaCl affected their antioxidant activity. The peroxide values and anisidine values of emulsions stored at 50 degrees C were measured over an 8-day period. Increased lipid oxidation occurred in the pH 7.0 emulsions and when 0.5 M NaCl was added to the pH 3.0 samples. Adding alpha-tocopherol, citric acid, or a combination of the two compounds slowed the formation of hydroperoxides and their subsequent decomposition products in pH 3.0 emulsions. PMID:14582985

  14. Comparison of removal of endodontic smear layer using ethylene glycol bis (beta-amino ethyl ether)-N, N, N', N'-tetraacetic acid and citric acid in primary teeth: A scanning electron microscopic study

    OpenAIRE

    Hegde, Rahul J.; Kavita Bapna

    2016-01-01

    Background: Root canal irrigants are considered momentous in their tissue dissolving property, eliminating microorganisms, and removing smear layer. The present study was aimed to compare the removal of endodontic smear layer using ethylene glycol bis (beta-amino ethyl ether)-N, N, N', N'-tetraacetic acid (EGTA) and citric acid solutions with saline as a control in primary anterior teeth. Materials and Methods: Thirty primary anterior teeth were chosen for the study. The teeth were distribute...

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

    OpenAIRE

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

    2011-01-01

    Carbonaceous meteorites deliver a variety of organic compounds to Earth that may have played a role in the origin and/or evolution of biochemical pathways. Some apparently ancient and critical metabolic processes require several compounds, some of which are relatively labile such as keto acids. Therefore, a prebiotic setting for any such individual process would have required either a continuous distant source for the entire suite of intact precursor molecules and/or an energetic and compact ...

  16. Effects of Citric Acid and Malic Acid on Nicotine Content in Flue-cured Tobacco%柠檬酸和苹果酸对烤烟烟碱含量的影响

    Institute of Scientific and Technical Information of China (English)

    张洁; 陆引罡; 余洁

    2012-01-01

    为了解决上部烟叶烟碱含量过高的问题,以云烟87为试材,通过大田和盆栽试验相结合,于烟株打顶后分别用不同浓度柠檬酸、苹果酸浸泡的棉球包扎茎顶端进行抑制烟碱上行积累的研究.结果表明:不同浓度柠檬酸、苹果酸处理均能降低烟叶中的烟碱含量,其中,浓度为2 mmol/L的柠檬酸和浓度为6 mmol/L的苹果酸均能明显降低上部烟叶的烟碱含量,降幅分别为36.9%和40.3%.结论:该方法降低烟叶尤其是上部烟叶烟碱含量的效果较为显著.%In order to reduce the content of nicotine in upper leaves, citric acid and malic acid were used to reduce nicotine of upper leaves through restraining uplink transportation of nicotine. The test material was the Yunyan87, through the field trial and pot experiment. After removing the shoot apex, the stem tops were binded with tampons soaked with citric acid, malic acid in different concentrations. The results showed that different concentrations of citric acid and malic acid treatment could reduce the content of nicotine in tobacco. Compared with blank control, 2 mmol/L and 6 mmol/L of citric acid could significantly reduce the content of upper leaves, with the decreasing range of 36. 9% and 40. 3%, respectively.

  17. Study of the influence of the citric and oxalic acid in the uranyl sorption in ZrP2O7 for their use in contention barriers

    International Nuclear Information System (INIS)

    Countries which produce electricity by nuclear means, such as Mexico, need to develop a technology for that at long term safe containment of nuclear waste that are produced in nuclear power plants, for now, the arrangement of these is made by international companies, as which is extremely expensive. The most accepted proposal for the containment of radioactive waste is the Deep Geological Repository (DGR), which consists of a number of natural barriers and of engineering barriers. Currently, barriers to engineering and materials that the make up are still under study, because must meet a series of structural criteria and chemical such as high insolubility, thermal and chemical stability with ionizing radiation. The surface must have adsorbed features of ions and organic compounds dissolved in infiltration water that could penetrate for a crack in the DGR. This study focuses, as first stage, is the uranyl sorption on zirconium diphosphate in various conditions of time, concentration and ph, then evaluates the influence of citric acid and oxalic acid on the sorption of uranyl on ZrP2O7, in order to model the behaviour of alpha emitters that are dissolved by percolating water laden with salts and organic matter, that infiltrates might during catastrophic events in the DGR. It was confirmed the purity of the zirconium diphosphate because it was synthesized from sea sand with the physicochemical characterization and superficial. The proposed methodology included elemental analysis by neutron activation and X-ray emission induced by charged particles, functional group analysis with infrared spectroscopy, morphology with scanning electron microscopy, crystallinity with transmission electron microscopy and X-ray diffraction. For properties surface was determined, the specific area using Bet multipoint technique, acidity constants in the FITEQL 4.0 program, the hydration time was obtained from literature, the point of zero charge was identified with a mass titration and

  18. Cloning and Characterization of a Pyruvate Carboxylase Gene from Penicillium rubens and Overexpression of the Genein the Yeast Yarrowia lipolytica for Enhanced Citric Acid Production.

    Science.gov (United States)

    Fu, Ge-Yi; Lu, Yi; Chi, Zhe; Liu, Guang-Lei; Zhao, Shou-Feng; Jiang, Hong; Chi, Zhen-Ming

    2016-02-01

    In this study, a pyruvate carboxylase gene (PYC1) from a marine fungus Penicillium rubens I607 was cloned and characterized. ORF of the gene (accession number: KM397349.1) had 3534 bp encoding 1177 amino acids with a molecular weight of 127.531 kDa and a PI of 6.20. The promoter of the gene was located at -1200 bp and contained a TATAA box, several CAAT boxes and a sequence 5'-SYGGRG-3'. The PYC1 deduced from the gene had no signal peptide, was a homotetramer (α4), and had the four functional domains. After expression of the PYC1 gene from the marine fungus in the marine-derived yeast Yarrowia lipolytica SWJ-1b, the transformant PR32 obtained had much higher specific pyruvate carboxylase activity (0.53 U/mg) than Y. lipolytica SWJ-1b (0.07 U/mg), and the PYC1 gene expression (133.8%) and citric acid production (70.2 g/l) by the transformant PR32 were also greatly enhanced compared to those (100 % and 27.3 g/l) by Y. lipolytica SWJ-1b. When glucose concentration in the medium was 60.0 g/l, citric acid (CA) concentration formed by the transformant PR32 was 36.1 g/l, leading to conversion of 62.1% of glucose into CA. During a 10-l fed-batch fermentation, the final concentration of CA was 111.1 ± 1.3 g/l, the yield was 0.93 g/g, the productivity was 0.46 g/l/h, and only 1.72 g/l reducing sugar was left in the fermented medium within 240 h. HPLC analysis showed that most of the fermentation products were CA. However, minor malic acid and other unknown products also existed in the culture. PMID:26470708

  19. Effects of tetracycline-containing gel and a mixture of tetracycline and citric acid-containing gel on non-surgical periodontal therapy

    Directory of Open Access Journals (Sweden)

    Renny Paul George

    2013-01-01

    Full Text Available Aims and Objectives: The purpose of this study was to assess the clinical and microbiological effects of a newly developed root-conditioning gel system containing tetracycline and a mixture of tetracycline and citric acid on non-surgical periodontal therapy. Materials and Methods: Four anterior teeth from four quadrants with a probing depth of 4-6 mm, in each of the 20 subjects with chronic periodontitis, were subjected to four different modalities of treatment. A total of 80 teeths were divided into four groups of 20 teeth each taken from separate quadrants, on the basis of one of the following four treatments: (1 Root planning alone in first quadrant (RP group; (2 tetracycline-containing gel in the second quadrant (TCG group; (3 root planning plus tetracycline-containing gel in third quadrant (RP + TCG group; (4 root planning plus a mixture of tetracycline and citric acid-containing gel in fourth quadrant (RP + TC-CAG group. Plaque index (PI, sulcular bleeding index, probing pocket depth, and clinical attachment level were measured for 0 day, 8 th week, and 12 th week, respectively. Subgingival plaque samples from each site were collected at the same visits and examined with dark field microscope for proportions of motile rods and spirochetes. Results: From 0 day to 12 th week, PI, sulcular bleeding index, probing pocket depth, and clinical attachment levels decreased significantly in all the groups. From 0 day to 12 th week, RP + TC-CAG group showed a significantly higher change in the PI score. From 0 day to 12 th week, RP group showed a significantly higher change in sulcular bleeding index score. A significant decrease in probing pocket depth and gain in clinical attachment level was noted at 12 th week in RP + TC-CAG group compared to the other groups. A significant decrease in the proportion of motile rods was found primarily in the RP + TC-CAG group. There was a decrease in the proportion of spirochetes in all the groups. Conclusion

  20. Foliar Sprays of Citric Acid and Malic Acid Modify Growth, Flowering, and Root to Shoot Ratio of Gazania (Gazania rigens L.): A Comparative Analysis by ANOVA and Structural Equations Modeling

    OpenAIRE

    Majid Talebi; Ebrahim Hadavi; Nima Jaafari

    2014-01-01

    Foliar application of two levels of citric acid and malic acid (100 or 300 mg L−1) was investigated on flower stem height, plant height, flower performance and yield indices (fresh yield, dry yield and root to shoot ratio) of Gazania. Distilled water was applied as control treatment. Multivariate analysis revealed that while the experimental treatments had no significant effect on fresh weight and the flower count, the plant dry weight was significantly increased by 300 mg L−1 malic acid. Cit...

  1. Synthesis of fluorescent carbon dots via microwave carbonization of citric acid in presence of tetraoctylammonium ion, and their application to cellular bioimaging

    International Nuclear Information System (INIS)

    A jelly-like form of carbon dots (C-dots) was prepared by microwave-assisted synthesis from citric acid in the presence of tetraoctylammonium bromide. The effect of the concentration of tetraoctylammonium bromide was examined. The synthesized carbon dots were characterized by UV–vis, XRD, FTIR, fluorescence and HR-TEM. Fluorescence extends from 350 to 600 nm, and the corresponding excitation wavelengths range from 300 to 460 nm. Quantum yields are at around 0.11. A cytotoxicity study showed carbon dots to be cell permeable and biocompatible which renders them appropriate for imaging applications. The dots were used to image HeLa cell lines via the blue fluorescence of the dots. (author)

  2. Citric acid modifies surface properties of commercial CeO2 nanoparticles reducing their toxicity and cerium uptake in radish (Raphanus sativus) seedlings

    International Nuclear Information System (INIS)

    Highlights: • The citric acid capping significantly reduced the ζ potential values. • As the amount of CA increased, thicker the layer surrounding the CeO2 NPs. • CeO2/CA NPs had better distribution and small particle size than bare CeO2 NPs. • CeO2/CA NPs decrease the Ce uptake by radish seedlings. -- Abstract: Little is known about the mobility, reactivity, and toxicity to plants of coated engineered nanoparticles (ENPs). Surface modification may change the interaction of ENPs with living organisms. This report describes surface changes in commercial CeO2 NPs coated with citric acid (CA) at molar ratios of 1:2, 1:3, 1:7, and 1:10 CeO2:CA, and their effects on radish (Raphanus sativus) seed germination, cerium and nutrients uptake. All CeO2 NPs and their absorption by radish plants were characterized by TEM, DLS, and ICP-OES. Radish seeds were germinated in pristine and CA coated CeO2 NPs suspensions at 50 mg/L, 100 mg/L, and 200 mg/L. Deionized water and CA at 100 mg/L were used as controls. Results showed ζ potential values of 21.6 mV and −56 mV for the pristine and CA coated CeO2 NPs, respectively. TEM images showed denser layers surrounding the CeO2 NPs at higher CA concentrations, as well as better distribution and smaller particle sizes. None of the treatments affected seed germination. However, at 200 mg/L the CA coated NPs at 1:7 ratio produced significantly (p ≤ 0.05) more root biomass, increased water content and reduced by 94% the Ce uptake, compared to bare NPs. This suggests that CA coating decrease CeO2 NPs toxicity to plants

  3. Solid-state thermal behavior and stability studies of theophylline–citric acid cocrystals prepared by neat cogrinding or thermal treatment

    International Nuclear Information System (INIS)

    To investigate the thermal behavior of cocrystal formed between anhydrous theophylline (TP) and anhydrous citric acid (CA) by neat manual cogrinding or thermal treatment, DSC and FTIR microspectroscopy with curve-fitting analysis were applied. The physical mixture and 60-min ground mixture were stored at 55±0.5 °C/40±2% RH condition to determine their stability behavior. Typical TP–CA cocrystals were prepared by slow solvent evaporation method. Results indicate that the cogrinding process could gradually induce the cocrystal formation between TP and CA. The IR spectral peak shift from 3495 to 3512 cm−1 and the stepwise appearance of several new IR peaks at 1731, 1712, 1676, 1651, 1557 and 1265 cm−1 with cogrinding time suggest that the mechanism of TP–CA cocrystal formation was evidenced by interacting TP with CA through the intermolecular O–H···O hydrogen bonding. The stability of 60-min ground mixture of TP–CA was confirmed at 55±0.5 °C/40±2% RH condition over a storage time of 60 days. - Garphical abstract: Cogrinding, thermal and solvent-evaporation methods might easily induce the theophylline–citric acid cocrystal formation. Highlights: ► Cogrinding process could gradually induce the cocrystal formation between TP and CA. ► The TP–CA cocrystal was formed through the intermolecular O–H···O hydrogen bonding. ► The 60-min TP–CA ground mixture was similar to the solvent-evaporated cocrystal. ► The thermal-induced TP–CA cocrystal formation was confirmed by pre-heating the physical mixture to 152 °C. ► The 60-min TP–CA ground mixture was stable at accelerated condition over a storage time of 60 days.

  4. Solid-state thermal behavior and stability studies of theophylline-citric acid cocrystals prepared by neat cogrinding or thermal treatment

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, Po-Chun; Lin, Hong-Liang [Department of Biotechnology, Yuanpei University, Hsin Chu, Taiwan (China); Wang, Shun-Li, E-mail: wangshunli@mail.ncyu.edu.tw [Department of Applied Chemistry, National Chia Yi University, Chia Yi, Taiwan (China); Lin, Shan-Yang, E-mail: sylin@mail.ypu.edu.tw [Department of Biotechnology, Yuanpei University, Hsin Chu, Taiwan (China)

    2012-08-15

    To investigate the thermal behavior of cocrystal formed between anhydrous theophylline (TP) and anhydrous citric acid (CA) by neat manual cogrinding or thermal treatment, DSC and FTIR microspectroscopy with curve-fitting analysis were applied. The physical mixture and 60-min ground mixture were stored at 55{+-}0.5 Degree-Sign C/40{+-}2% RH condition to determine their stability behavior. Typical TP-CA cocrystals were prepared by slow solvent evaporation method. Results indicate that the cogrinding process could gradually induce the cocrystal formation between TP and CA. The IR spectral peak shift from 3495 to 3512 cm{sup -1} and the stepwise appearance of several new IR peaks at 1731, 1712, 1676, 1651, 1557 and 1265 cm{sup -1} with cogrinding time suggest that the mechanism of TP-CA cocrystal formation was evidenced by interacting TP with CA through the intermolecular O-H{center_dot}{center_dot}{center_dot}O hydrogen bonding. The stability of 60-min ground mixture of TP-CA was confirmed at 55{+-}0.5 Degree-Sign C/40{+-}2% RH condition over a storage time of 60 days. - Garphical abstract: Cogrinding, thermal and solvent-evaporation methods might easily induce the theophylline-citric acid cocrystal formation. Highlights: Black-Right-Pointing-Pointer Cogrinding process could gradually induce the cocrystal formation between TP and CA. Black-Right-Pointing-Pointer The TP-CA cocrystal was formed through the intermolecular O-H{center_dot}{center_dot}{center_dot}O hydrogen bonding. Black-Right-Pointing-Pointer The 60-min TP-CA ground mixture was similar to the solvent-evaporated cocrystal. Black-Right-Pointing-Pointer The thermal-induced TP-CA cocrystal formation was confirmed by pre-heating the physical mixture to 152 Degree-Sign C. Black-Right-Pointing-Pointer The 60-min TP-CA ground mixture was stable at accelerated condition over a storage time of 60 days.

  5. Citric acid modifies surface properties of commercial CeO{sub 2} nanoparticles reducing their toxicity and cerium uptake in radish (Raphanus sativus) seedlings

    Energy Technology Data Exchange (ETDEWEB)

    Trujillo-Reyes, J. [Chemistry Department, The University of Texas at El Paso, 500 West University Av., El Paso, TX 79968 (United States); Vilchis-Nestor, A.R. [Centro Conjunto de Investigación en Química Sustentable UAEM—UNAM, Carretera Toluca—Atlacomulco km 14.5, San Cayetano, CP 50200 Toluca, Estado de México (Mexico); Majumdar, S. [Chemistry Department, The University of Texas at El Paso, 500 West University Av., 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 Av., El Paso, TX 79968 (United States); Peralta-Videa, J.R. [Chemistry Department, The University of Texas at El Paso, 500 West University Av., El Paso, TX 79968 (United States); Environmental Science and Engineering PhD program, The University of Texas at El Paso, 500 West University Ave., 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 Av., El Paso, TX 79968 (United States); Gardea-Torresdey, J.L., E-mail: jgardea@utep.edu [Chemistry Department, The University of Texas at El Paso, 500 West University Av., El Paso, TX 79968 (United States); Environmental Science and Engineering PhD program, The University of Texas at El Paso, 500 West University Ave., 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 Av., El Paso, TX 79968 (United States)

    2013-12-15

    Highlights: • The citric acid capping significantly reduced the ζ potential values. • As the amount of CA increased, thicker the layer surrounding the CeO{sub 2} NPs. • CeO{sub 2}/CA NPs had better distribution and small particle size than bare CeO{sub 2} NPs. • CeO{sub 2}/CA NPs decrease the Ce uptake by radish seedlings. -- Abstract: Little is known about the mobility, reactivity, and toxicity to plants of coated engineered nanoparticles (ENPs). Surface modification may change the interaction of ENPs with living organisms. This report describes surface changes in commercial CeO{sub 2} NPs coated with citric acid (CA) at molar ratios of 1:2, 1:3, 1:7, and 1:10 CeO{sub 2}:CA, and their effects on radish (Raphanus sativus) seed germination, cerium and nutrients uptake. All CeO{sub 2} NPs and their absorption by radish plants were characterized by TEM, DLS, and ICP-OES. Radish seeds were germinated in pristine and CA coated CeO{sub 2} NPs suspensions at 50 mg/L, 100 mg/L, and 200 mg/L. Deionized water and CA at 100 mg/L were used as controls. Results showed ζ potential values of 21.6 mV and −56 mV for the pristine and CA coated CeO{sub 2} NPs, respectively. TEM images showed denser layers surrounding the CeO{sub 2} NPs at higher CA concentrations, as well as better distribution and smaller particle sizes. None of the treatments affected seed germination. However, at 200 mg/L the CA coated NPs at 1:7 ratio produced significantly (p ≤ 0.05) more root biomass, increased water content and reduced by 94% the Ce uptake, compared to bare NPs. This suggests that CA coating decrease CeO{sub 2} NPs toxicity to plants.

  6. 柠檬酸对温室土壤磷有效性的影响%Effects of Citric Acid on Phosphorus Availability for Soil in Greenhouse Field

    Institute of Scientific and Technical Information of China (English)

    房福力; 姚志鹏; 林伟; 李玉中; 徐春英; 李巧珍

    2015-01-01

    温室菜地土壤面临磷肥大量投入,磷肥有效性低下等问题,为提高土壤中磷素的有效性,减少磷肥施用,亟待开展相关研究。以番茄为供试对象,研究温室番茄地施用柠檬酸对土壤有效磷时空变化及番茄产量的影响,试验设置磷肥和柠檬酸2个因素4个水平,采用完全随机设计,分别为:0(CA0)、0.42(CA1)、0.84(CA2)、1.26(CA3)kg·hm-2和0(P0)、96(P1)、168(P2)、240(P3)kg·hm-2。结果表明:与对照相比,施加柠檬酸后土壤pH极显著降低(P<0.01),CA3P0处理使土壤pH降低了0.62;不施加磷肥时,柠檬酸促进土壤磷素的释放,提高了土壤有效磷的含量;施加磷肥后,柠檬酸和磷肥交互作用可以显著提高表层0~20 cm土壤有效磷含量,但是过多施用柠檬酸和磷肥CA3P3处理使表层0~20 cm土壤有效磷含量降低,使20~40 cm土壤有效磷含量增加,并提高有效磷向下运移的可能性。合适的柠檬酸和磷肥配比CA2P2既可以获得较高番茄产量6.02 t·hm-2,又可以减少30%的磷肥施用量,同时降低磷素向深层运移的风险。%The utilization efficiency of phosphorus fertilizers in vegetable production under greenhouse condition is low in spite of its exces-sive use. Thus, it need to improve the availability of phosphorus and consequently reduce its application rate.In this study, a greenhouse trial was conducted to reveal the effects of citric acid on soil available phosphorus and tomato yield. Four phosphate fertilizer application rates(0, 96, 168, 240 kg·hm-2, denoted as P0, P1, P2, P3, respectively)and four citric acid levels(0, 0.42, 0.84, 1.26 kg·hm-2, denoted as CA0, CA1, CA2, CA3, respectively)were arranged with the method of completely random design. The results showed that soil pH decreased sig-nificantly(P<0.01)with the increment of citric acid addition level, and it decreased by 0.62 units for CA3P0 compared with

  7. Effect of EDTA, EDDS, NTA and citric acid on electrokinetic remediation of As, Cd, Cr, Cu, Ni, Pb and Zn contaminated dredged marine sediment.

    Science.gov (United States)

    Song, Yue; Ammami, Mohamed-Tahar; Benamar, Ahmed; Mezazigh, Salim; Wang, Huaqing

    2016-06-01

    In recent years, electrokinetic (EK) remediation method has been widely considered to remove metal pollutants from contaminated dredged sediments. Chelating agents are used as electrolyte solutions to increase metal mobility. This study aims to investigate heavy metal (HM) (As, Cd, Cr, Cu, Ni, Pb and Zn) mobility by assessing the effect of different chelating agents (ethylenediaminetetraacetic acid (EDTA), ethylenediaminedisuccinic acid (EDDS), nitrilotriacetic acid (NTA) or citric acid (CA)) in enhancing EK remediation efficiency. The results show that, for the same concentration (0.1 mol L(-1)), EDTA is more suitable to enhance removal of Ni (52.8 %), Pb (60.1 %) and Zn (34.9 %). EDDS provides effectiveness to increase Cu removal efficiency (52 %), while EDTA and EDDS have a similar enhancement removal effect on As EK remediation (30.5∼31.3 %). CA is more suitable to enhance Cd removal (40.2 %). Similar Cr removal efficiency was provided by EK remediation tests (35.6∼43.5 %). In the migration of metal-chelate complexes being directed towards the anode, metals are accumulated in the middle sections of the sediment matrix for the tests performed with EDTA, NTA and CA. But, low accumulation of metal contamination in the sediment was observed in the test using EDDS. PMID:26782321

  8. Proposed formation mechanism and active species of hydrogen molecules generated from a novel magnesium-citric acid-hydroxypropyl cellulose coating (MgCC) material

    Science.gov (United States)

    Kobayashi, Shigeki; Chikuma, Toshiyuki; Chiba, Kazuyoshi; Tsuchiya, Daisuke; Hirai, Tomomitsu

    2016-02-01

    The presence of acids is known to accelerate the reaction (Mg + 2H2O = Mg(OH)2 + H2). We developed a novel Mg-citric acid coating (MgCC) material produced by milling Mg powder coated with hydroxypropyl cellulose (HPC); because of its H2 generation, this material could be used in antioxidant therapy and antiaging applications. After milling in the presence of citric acid, this material produced H2-rich water upon addition to cooled water. Although the reaction was considered to involve a two-electron transfer from Mg to 2H2O, the role of the acid in H2 generation remains incompletely understood. To clarify the reaction mechanism, we performed studies on the deuterium kinetic isotope effects (KIE) and electron spin resonance (ESR). We observed differences in the concentration ratios, such as H2/D2 > 1 and H2/(H2 + D2 + HD) > 1, involved in H2, D2, and (H2 + D2 + HD) production, and found that adducts with hydrogen atoms (Hrad) were not obtained from the spin-trapping reaction between 5-(2, 2-Dimethyl-1,3-propoxy cyclophosphoryl)-5-methyl-1-pyrroline N-oxide (CYPMPO) and the MgCC material. The H2, D2, and HD produced from MgCC were identified by using a gas chromatograph connected to a mass spectrometer. The spin-trapping techniques showed that the Hrad adducts formed by the reaction of NaBH4 with CYPMPO could not be observed from reaction of MGCC with CYPMPO in H2O. The data suggest that the rate-controlling step and proposed transition state (TS) exist in the reaction pathway of the O-H bond cleavage and H-H bond formation. A TS of a structure such as [Mg(OH2)2]∗ could be expected in the reaction pathway between Mg and 2H2O by density functional theory calculations. Also, these results show that H2 generation is accelerated in the presence of acids because the activation energy of the TS is significantly smaller than that of H2O.

  9. Synthesis of Copolymer of Citric Acid Stearic Acid and Pentaerythritol%柠檬酸硬脂酸季戊四醇三元共聚蜡状物的研制

    Institute of Scientific and Technical Information of China (English)

    张建雨; 陈洁

    2012-01-01

    Citric stearic pentaerythritol ester was synthesized from citric acid,stearic acid and pentaerythritol in two steps.The reaction condition was optimumed as follow: in the first step of the reaction,n(Pentaerythritol)∶n(Stearic acid)=1∶1,the temperature was 200 ℃,reaction time was 1 h,mass fraction of p-toluene sulfonic acid was 0.4 %;in the second step of the reaction,n(citric acid)∶n(Pentaerythritol)=0.48∶1,reaction temperature was 150 ℃,reaction time was 3 h.The final product looks like wax,its character was as follow: acid value was 2.2 mgKOH/g,penertration degree was 0.1 mm,dropping point is 70 ℃.%以柠檬酸、季戊四醇、硬脂酸为原料,采用直接酯化的两步反应合成了柠檬酸硬脂酸季戊四醇酯蜡,并对反应条件进行了优化。固定季戊四醇为0.1 mol的最佳条件为:第一步反应温度为200℃,时间1 h,硬脂酸用量28 g,催化剂为总质量的0.4%;第二步柠檬酸用量为10 g,反应温度150℃,反应时间3 h。最终产物为蜡状物质,酸值为2.2 mgKOH/g,针入度为0.1 mm,滴熔点为70℃。

  10. Noble Metal Decoration and Presulfation on TiO2: Increased Photocatalytic Activity and Efficient Esterification of n-Butanol with Citric Acid

    Directory of Open Access Journals (Sweden)

    Yu Niu

    2016-01-01

    Full Text Available TiO2 has been widely used as a key catalyst in photocatalytic reactions; it also shows good catalytic activity for esterification reactions. Different sulfated M-TiO2 nanoparticles (M = Ag, Au, Rh, and Pt were prepared by photodeposition and ultrasonic methods. The results show that the noble metal nanoparticles, which were loaded onto a TiO2 surface, slightly affected the crystal phase and particle size of TiO2. Among all the catalysts, SO42-/Au-TiO2 exhibited the best catalytic activity in the esterification reaction for the synthesis of citric acid n-butyl acetate and in the decomposition of methyl orange, as confirmed by a high conversion rate of up to 98.2% and 100% degradation rate, respectively. This can be attributed to an increase in the Lewis acidity of the catalyst and increased separation efficiency of electron-hole pairs. This superior catalyst has great potential applications in esterification reactions and wastewater treatments.

  11. Minimal inhibitory concentrations of undissociated lactic, acetic, citric and propionic acid for Listeria monocytogenes under conditions relevant to cheese

    NARCIS (Netherlands)

    Wemmenhove, Ellen; Valenberg, van Hein J.F.; Zwietering, Marcel H.; Hooijdonk, van Toon C.M.; Wells-Bennik, Marjon H.J.

    2016-01-01

    Minimal inhibitory concentrations (MICs) of undissociated lactic acid were determined for six different Listeria monocytogenes strains at 30 °C and in a pH range of 4.2-5.8. Small increments in pH and acid concentrations were used to accurately establish the growth/no growth limits of L. monocyto

  12. Relation between citric acid production by solid-state fermentation from cassava bagasse and respiration of Aspergillus niger LPB 21 in semi-pilot scale

    Directory of Open Access Journals (Sweden)

    Flávera Camargo Prado

    2005-06-01

    Full Text Available The aim of this work was to study the relation between citric acid production and respiration of Aspergillus niger LPB 21 in solid-state fermentation of cassava bagasse. The experiments were carried out in horizontal drum bioreactor coupled with a gas chromatography system. Fermentation was conduced for 144 h with initial substrate moisture of 60% using heat-treated cassava bagasse as sole carbon source. The exhausted air from the bioreactor was analyzed for the monitoring of CO2 produced and O2 consumed in order to estimate the biomass biosynthesis by the fungal culture. The metabolic activity of A. niger growth was associated to citric acid production. The system using FERSOL software determined 4.372 g of biomass/g of consumed O2. Estimated and analytically determined biomass values followed the same pattern showing that the applied mathematical model was adapted.Este estudo permitiu verificar a relação ente a produção de ácido cítrico e a respiração do Aspergillus niger LPB 21 na fermentação no estado sólido do bagaço de mandioca. Os experimentos foram realizados em biorreator tipo tambor horizontal acoplado com um sistema de cromatografia gasosa. A fermentação foi conduzida durante 144 h com 60% de umidade inicial do substrato usando bagaço de mandioca termicamente tratado como única fonte de carbono. O ar de saída do biorreator foi analisado para monitorar a produção de CO2 e o consumo de O2 com o objetivo de estimar a biomassa sintetizada pelo fungo. A atividade metabólica do crescimento do Aspergillus niger está associada à produção de ácido cítrico. Usando o software FERSOL, o sistema determinou uma biomassa de 4.372 g de biomassa/g de O2 consumido. Os valores da biomassa estimada e da determinada analiticamente seguiram a mesma tendência mostrando que o modelo matemático aplicado foi adaptado.

  13. Nanoporous alumina formed by self-organized two-step anodization of Ni{sub 3}Al intermetallic alloy in citric acid

    Energy Technology Data Exchange (ETDEWEB)

    Stepniowski, Wojciech J., E-mail: wstepniowski@wat.edu.pl [Department of Advanced Materials and Technology, Faculty of New Technologies and Chemistry, Military University of Technology, Kaliskiego 2 Str., 00-908 Warszawa (Poland); Cieslak, Grzegorz; Norek, Malgorzata; Karczewski, Krzysztof; Michalska-Domanska, Marta; Zasada, Dariusz; Polkowski, Wojciech; Jozwik, Pawel; Bojar, Zbigniew [Department of Advanced Materials and Technology, Faculty of New Technologies and Chemistry, Military University of Technology, Kaliskiego 2 Str., 00-908 Warszawa (Poland)

    2013-01-01

    Highlights: Black-Right-Pointing-Pointer Anodic porous alumina was formed by Ni{sub 3}Al intermetallic alloy anodization. Black-Right-Pointing-Pointer The anodizations were conducted in 0.3 M citric acid. Black-Right-Pointing-Pointer Nanopores geometry depends on anodizing voltage. Black-Right-Pointing-Pointer No barrier layer was formed during anodization. - Abstract: Formation of the nanoporous alumina on the surface of Ni{sub 3}Al intermetallic alloy has been studied in details and compared with anodization of aluminum. Successful self-organized anodization of this alloy was performed in 0.3 M citric acid at voltages ranging from 2.0 to 12.0 V using a typical two-electrode cell. Current density records revealed different mechanism of the porous oxide growth when compared to the mechanism pertinent for the anodization of aluminum. Electrochemical impedance spectroscopy experiments confirmed the differences in anodic oxide growth. Surface and cross-sections of the Ni{sub 3}Al intermetallic alloy with anodic oxide were observed with field-emission scanning electron microscope and characterized with appropriate software. Nanoporous oxide growth rate was estimated from cross-sectional FE-SEM images. The lowest growth rate of 0.14 {mu}m/h was found for the anodization at 0 Degree-Sign C and 2.0 V. The highest one - 2.29 {mu}m/h - was noticed for 10.0 V and 30 Degree-Sign C. Pore diameter was ranging from 18.9 nm (2.0 V, 0 Degree-Sign C) to 32.0 nm (12.0 V, 0 Degree-Sign C). Interpore distance of the nanoporous alumina was ranging from 56.6 nm (2.0 V, 0 Degree-Sign C) to 177.9 nm (12.0 V, 30 Degree-Sign C). Pore density (number of pore occupying given area) was decreasing with anodizing voltage increase from 394.5 pores/{mu}m{sup 2} (2.0 V, 0 Degree-Sign C) to 94.9 pores/{mu}m{sup 2} (12.0 V, 0 Degree-Sign C). All the geometrical features of the anodic alumina formed by two-step self-organized anodization of Ni{sub 3}Al intermetallic alloy are depending on the

  14. Comparison of removal of endodontic smear layer using ethylene glycol bis (beta-amino ethyl ether-N, N, N', N'-tetraacetic acid and citric acid in primary teeth: A scanning electron microscopic study

    Directory of Open Access Journals (Sweden)

    Rahul J Hegde

    2016-01-01

    Full Text Available Background: Root canal irrigants are considered momentous in their tissue dissolving property, eliminating microorganisms, and removing smear layer. The present study was aimed to compare the removal of endodontic smear layer using ethylene glycol bis (beta-amino ethyl ether-N, N, N', N'-tetraacetic acid (EGTA and citric acid solutions with saline as a control in primary anterior teeth. Materials and Methods: Thirty primary anterior teeth were chosen for the study. The teeth were distributed into three groups having ten teeth each. Following instrumentation, root canals of the first group were treated with 17% EGTA and the second group with 6% citric acid. Only saline was used as an irrigant for the control group. Then, the teeth were subjected to scanning electron microscopy (SEM study. The scale given by Rome et al. for the smear layer removal was used in the present study. Results: The pictures from the SEM showed that among the tested irrigants, 17% EGTA + 5% sodium hypochlorite (NaOCl group showed the best results when compared to other groups. Conclusion: The results advocate that the sequential irrigation of the pulp canal walls with 17% EGTA followed by 5% NaOCl produced efficacious and smear-free root canal walls.

  15. Comparison of removal of endodontic smear layer using ethylene glycol bis (beta-amino ethyl ether)-N, N, N', N'-tetraacetic acid and citric acid in primary teeth: A scanning electron microscopic study

    Science.gov (United States)

    Hegde, Rahul J.; Bapna, Kavita

    2016-01-01

    Background: Root canal irrigants are considered momentous in their tissue dissolving property, eliminating microorganisms, and removing smear layer. The present study was aimed to compare the removal of endodontic smear layer using ethylene glycol bis (beta-amino ethyl ether)-N, N, N', N'-tetraacetic acid (EGTA) and citric acid solutions with saline as a control in primary anterior teeth. Materials and Methods: Thirty primary anterior teeth were chosen for the study. The teeth were distributed into three groups having ten teeth each. Following instrumentation, root canals of the first group were treated with 17% EGTA and the second group with 6% citric acid. Only saline was used as an irrigant for the control group. Then, the teeth were subjected to scanning electron microscopy (SEM) study. The scale given by Rome et al. for the smear layer removal was used in the present study. Results: The pictures from the SEM showed that among the tested irrigants, 17% EGTA + 5% sodium hypochlorite (NaOCl) group showed the best results when compared to other groups. Conclusion: The results advocate that the sequential irrigation of the pulp canal walls with 17% EGTA followed by 5% NaOCl produced efficacious and smear-free root canal walls. PMID:27307670

  16. Effects of Continuous Triiodothyronine Infusion on Citric Acid Cycle in the Normal Immature Swine Heart under Extracorporeal Membrane Oxygenation in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Kajimoto, Masaki [Seattle Children' s Research Inst., Seattle, WA (United States); O' Kelly-Priddy, Colleen M. [Seattle Children' s Research Inst., Seattle, WA (United States); Univ. of Washington, Seattle, WA (United States); Ledee, Dolena R. [Seattle Children' s Research Inst., Seattle, WA (United States); Xu, Chun [Seattle Children' s Research Inst., Seattle, WA (United States); Isern, Nancy G. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Olson, Aaron [Seattle Children' s Research Inst., Seattle, WA (United States); Univ. of Washington, Seattle, WA (United States); Portman, Michael A. [Seattle Children' s Research Inst., Seattle, WA (United States); Univ. of Washington, Seattle, WA (United States)

    2014-02-13

    Extracorporeal membrane oxygenation (ECMO) is frequently used in infants with postoperative cardiopulmonary failure. ECMO also suppresses circulating triiodothyronine (T3) levels and modifies myocardial metabolism. We assessed the hypothesis that T3 supplementation reverses ECMO induced metabolic abnormalities in the immature heart. Twenty-two male Yorkshire pigs (age 25-38 days) with ECMO were received [2-13C]lactate, [2,4,6,8-13C]octanoate (medium chain fatty acid) and [U-13C]long-chain fatty acids as metabolic tracers either systemically (totally physiological intracoronary concentration) or directly into the coronary artery (high substrate concentration) for the last 60 minutes of each protocol. Nuclear magnetic resonance (NMR) analysis of left ventricular tissue determined the fractional contribution (Fc) of these substrates to the citric acid cycle (CAC). Fifty percent of the pigs in each group received intravenous T3 supplement (bolus at 0.6 μg/kg and then continuous infusion at 0.2 μg/kg/hour) during ECMO. Under both substrate loading conditions T3 significantly increased lactate-Fc with a marginal increase in octanoate-Fc. Both T3 and high substrate provision increased myocardial energy status indexed by [Phosphocreatine]/[ATP]. In conclusion, T3 supplementation promoted lactate metabolism to the CAC during ECMO suggesting that T3 releases inhibition of pyruvate dehydrogenase. Manipulation of substrate utilization by T3 may be used therapeutically during ECMO to improve resting energy state and facilitate weaning.

  17. The effect of dual complexing agents of lactic and citric acids on the formation of sol-gel derived Ag–PbTiO3 percolative thin film

    International Nuclear Information System (INIS)

    Controlling the formation of conductive particles to be nano-scale is important for achieving percolation effect in metal dispersed thin film composite to contribute extraordinary dielectric properties required for miniaturization of electronic devices. In this paper, lactic acid (LA) and citric acid (CA) were used as dual complexing agents to prepare a typical Ag nanoparticle dispersed PbTiO3 (PTO) composite thin film by using a sol-gel method. The phase structure of the thin film and the coordination effect between complexing agent and metallic ions were investigated. It revealed that LA coordinated with Ti4+ and Pb2+ and CA coordinated with Ag+. Lead was fixed inside the gel network by LA and restricted to evaporate during heat treatment thus the pyrochlore phase was prevented from forming in the thin film. Ag+ was coordinated by CA and the diffusion and thus aggregation of silver during gelation and annealing process were weakened. Silver nanoparticles dispersed in the PTO matrix formed with dual complexing agents of LA and CA introduced during the preparation process. The composite thin film of perfect perovskite phase with silver nanoparticles embedded was obtained at the molar ratio of LA/lead = 0.5 and CA/lead = 0.5. The dielectric constant of the thin film with silver nanoparticles is 5 times higher than that without silver nanoparticles. - Highlights: • Ag nanoparticle–PbTiO3 percolative film with high dielectric property is prepared. • Evaporation of lead was prevented by coordinating Pb with lactic acid agent. • Dual complexing agents contribute block and pinning effects to form Ag nanoparticles

  18. Collagen based film with well epithelial and stromal regeneration as corneal repair materials: Improving mechanical property by crosslinking with citric acid.

    Science.gov (United States)

    Zhao, Xuan; Liu, Yang; Li, Weichang; Long, Kai; Wang, Lin; Liu, Sa; Wang, Yingjun; Ren, Li

    2015-10-01

    Corneal disease can lead to vision loss. It has become the second greatest cause of blindness in the world, and keratoplasty is considered as an effective treatment method. This paper presents the crosslinked collagen (Col)-citric acid (CA) films developed by making use of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS). The results showed that the Col-CA films had necessary optical performance, water content. The collagenase resistance of CA crosslinked films was superior to that of EDC crosslinked films. And CA5 film (Col:CA:EDC:NHS=60:3:10:10) had the best mechanical properties. Cell experiments showed that CA5 film was non-cytotoxic and human corneal epithelial cells could proliferate well on the films. Lamellar keratoplasty showed that the CA5 film could be sutured in the rabbit eyes and was epithelialized completely in about 10 days, and the transparency was restored quickly in 30±5 days. No inflammation and corneal neovascularization were observed at 6 months. Corneal stroma had been repaired; stromal cells and neo-stroma could be seen in the area of operation from the hematoxylin-eosin stained histologic sections and anterior segment optical coherence tomography images. These results indicated that Col-CA films were highly promising biomaterials that could be used in corneal tissue engineering and a variety of other tissue engineering applications. PMID:26117756

  19. Improvement of phytoextraction and antioxidative defense in Solanum nigrum L. under cadmium stress by application of cadmium-resistant strain and citric acid

    International Nuclear Information System (INIS)

    Remediation of plant-microorganism-chelates synergy has been proposed as an effective remediation method for enhancing the removal efficiency of heavy metal. Manipulation of the antioxidative system increases plant tolerance, thereby potentially enhancing the uptake capacity to heavy metal. In this study, we investigated the possibility of improving the phytoextraction of Cd and the antioxidative defense of Solanum nigrum L. by application of a new isolated strain (Paecilomyces lilacinus NH1) (PLNH1) and citric acid (CA). The results showed that application of CA or PLNH1 significantly promoted S. nigrum's growth under Cd stress, but the synergistic effect of CA and PLNH1 on S. nigrum's growth was more obvious. The coexistence of CA and PLNH1 could enhance about 30% of Cd accumulation in different organs of S. nigrum compared to the treatment without the addition of CA and PLNH1, whereas single CA or PLNH1 added treatment only enhanced about 10-15% of Cd accumulation in different organs of S. nigrum. The antioxidative defense in S. nigrum under Cd stress was significantly improved as result of application of CA and PLNH1. The responses of antioxidative enzymes to Cd stress significantly decreased following application of CA and PLNH1, and the oxidative stress experienced by the plant due to Cd in the soil was significantly alleviated.

  20. Oligosaccharide-based Surfactant/Citric Acid Buffer System Stabilizes Lactate Dehydrogenase during Freeze-drying and Storage without the Addition of Natural Sugar.

    Science.gov (United States)

    Ogawa, Shigesaburo; Kawai, Ryuichiro; Koga, Maito; Asakura, Kouichi; Takahashi, Isao; Osanai, Shuichi

    2016-06-01

    Experiments were conducted to assess the maintenance effects of oligosaccharide-based surfactants on the enzymatic activity of a model protein, lactate dehydrogenase (LDH), during freeze-drying and room temperature storage using the citric acid buffer system. Oligosaccharide-based surfactants, which exhibit a high glass transition temperature (Tg), promoted the eminent retention of enzymatic activity during these protocols, whereas monosaccharide-based surfactants with a low Tg displayed poor performance at high concentration, albeit much better than that of Tween 80 at middle concentration. The increase in the alkyl chain length did not exert positive effects as observed for the maintenance effect during freeze-thawing, but an amphiphilic nature and a glass forming ability were crucial for the effective stabilization at a low excipient concentration during freeze-drying. Even a low oligosaccharide-based surfactant content (0.1 mg mL(-1)) could maintain LDH activity during freeze-drying, but a high surfactant content (1.0 mg mL(-1)) was required to prevent buffer precipitation and retain high LDH activity on storage. Regarding storage, glass formation restricted molecular mobility in the lyophilized matrix, and LDH activity was effectively retained. The present results describe a strategy based on the glass-forming ability of surfactant-type excipients that affords a natural sugar-free formulation or an alternative use for polysorbate-type surfactants. PMID:27181251

  1. Ghrelin is produced in taste cells and ghrelin receptor null mice show reduced taste responsivity to salty (NaCl and sour (citric acid tastants.

    Directory of Open Access Journals (Sweden)

    Yu-Kyong Shin

    Full Text Available BACKGROUND: The gustatory system plays a critical role in determining food preferences, food intake and energy balance. The exact mechanisms that fine tune taste sensitivity are currently poorly defined, but it is clear that numerous factors such as efferent input and specific signal transduction cascades are involved. METHODOLOGY/PRINCIPAL FINDINGS: Using immunohistochemical analyses, we show that ghrelin, a hormone classically considered to be an appetite-regulating hormone, is present within the taste buds of the tongue. Prepro-ghrelin, prohormone convertase 1/3 (PC 1/3, ghrelin, its cognate receptor (GHSR, and ghrelin-O-acyltransferase (GOAT , the enzyme that activates ghrelin are expressed in Type I, II, III and IV taste cells of mouse taste buds. In addition, ghrelin and GHSR co-localize in the same taste cells, suggesting that ghrelin works in an autocrine manner in taste cells. To determine a role for ghrelin in modifying taste perception, we performed taste behavioral tests using GHSR null mice. GHSR null mice exhibited significantly reduced taste responsivity to sour (citric acid and salty (sodium chloride tastants. CONCLUSIONS/SIGNIFICANCE: These findings suggest that ghrelin plays a local modulatory role in determining taste bud signaling and function and could be a novel mechanism for the modulation of salty and sour taste responsivity.

  2. Improvement of phytoextraction and antioxidative defense in Solanum nigrum L. under cadmium stress by application of cadmium-resistant strain and citric acid

    Energy Technology Data Exchange (ETDEWEB)

    Gao Yang, E-mail: gaoyang0898@sjtu.edu.cn [School of Environmental Science and Engineering, Shanghai Jiaotong University, Shanghai, 200240 (China); Key Laboratory of Soil and Water Conservation and Desertification Control, College of Soil and Water Conservation, Beijing Forestry University, Beijing 100083 (China); Miao Chiyuan [Department of Environmental Engineering, Peking University, Beijing, 100871 (China); Mao Liang [School of Environmental Science and Engineering, Shanghai Jiaotong University, Shanghai, 200240 (China); School of Agriculture and Biology, Shanghai Jiaotong University, Shanghai, 200240 (China); Zhou Pei [School of Agriculture and Biology, Shanghai Jiaotong University, Shanghai, 200240 (China); Key Laboratory of Urban Agriculture (South), Ministry of Agriculture, Shanghai 200240 (China); Jin Zhiguo; Shi Wanjun [School of Agriculture and Biology, Shanghai Jiaotong University, Shanghai, 200240 (China)

    2010-09-15

    Remediation of plant-microorganism-chelates synergy has been proposed as an effective remediation method for enhancing the removal efficiency of heavy metal. Manipulation of the antioxidative system increases plant tolerance, thereby potentially enhancing the uptake capacity to heavy metal. In this study, we investigated the possibility of improving the phytoextraction of Cd and the antioxidative defense of Solanum nigrum L. by application of a new isolated strain (Paecilomyces lilacinus NH1) (PLNH1) and citric acid (CA). The results showed that application of CA or PLNH1 significantly promoted S. nigrum's growth under Cd stress, but the synergistic effect of CA and PLNH1 on S. nigrum's growth was more obvious. The coexistence of CA and PLNH1 could enhance about 30% of Cd accumulation in different organs of S. nigrum compared to the treatment without the addition of CA and PLNH1, whereas single CA or PLNH1 added treatment only enhanced about 10-15% of Cd accumulation in different organs of S. nigrum. The antioxidative defense in S. nigrum under Cd stress was significantly improved as result of application of CA and PLNH1. The responses of antioxidative enzymes to Cd stress significantly decreased following application of CA and PLNH1, and the oxidative stress experienced by the plant due to Cd in the soil was significantly alleviated.

  3. Solid-state thermal behavior and stability studies of theophylline-citric acid cocrystals prepared by neat cogrinding or thermal treatment

    Science.gov (United States)

    Hsu, Po-Chun; Lin, Hong-Liang; Wang, Shun-Li; Lin, Shan-Yang

    2012-08-01

    To investigate the thermal behavior of cocrystal formed between anhydrous theophylline (TP) and anhydrous citric acid (CA) by neat manual cogrinding or thermal treatment, DSC and FTIR microspectroscopy with curve-fitting analysis were applied. The physical mixture and 60-min ground mixture were stored at 55±0.5 °C/40±2% RH condition to determine their stability behavior. Typical TP-CA cocrystals were prepared by slow solvent evaporation method. Results indicate that the cogrinding process could gradually induce the cocrystal formation between TP and CA. The IR spectral peak shift from 3495 to 3512 cm-1 and the stepwise appearance of several new IR peaks at 1731, 1712, 1676, 1651, 1557 and 1265 cm-1 with cogrinding time suggest that the mechanism of TP-CA cocrystal formation was evidenced by interacting TP with CA through the intermolecular O-H···O hydrogen bonding. The stability of 60-min ground mixture of TP-CA was confirmed at 55±0.5 °C/40±2% RH condition over a storage time of 60 days.

  4. The intrinsic antimicrobial activity of citric acid-coated manganese ferrite nanoparticles is enhanced after conjugation with the antifungal peptide Cm-p5

    Science.gov (United States)

    Lopez-Abarrategui, Carlos; Figueroa-Espi, Viviana; Lugo-Alvarez, Maria B; Pereira, Caroline D; Garay, Hilda; Barbosa, João ARG; Falcão, Rosana; Jiménez-Hernández, Linnavel; Estévez-Hernández, Osvaldo; Reguera, Edilso; Franco, Octavio L; Dias, Simoni C; Otero-Gonzalez, Anselmo J

    2016-01-01

    Diseases caused by bacterial and fungal pathogens are among the major health problems in the world. Newer antimicrobial therapies based on novel molecules urgently need to be developed, and this includes the antimicrobial peptides. In spite of the potential of antimicrobial peptides, very few of them were able to be successfully developed into therapeutics. The major problems they present are molecule stability, toxicity in host cells, and production costs. A novel strategy to overcome these obstacles is conjugation to nanomaterial preparations. The antimicrobial activity of different types of nanoparticles has been previously demonstrated. Specifically, magnetic nanoparticles have been widely studied in biomedicine due to their physicochemical properties. The citric acid-modified manganese ferrite nanoparticles used in this study were characterized by high-resolution transmission electron microscopy, which confirmed the formation of nanocrystals of approximately 5 nm diameter. These nanoparticles were able to inhibit Candida albicans growth in vitro. The minimal inhibitory concentration was 250 µg/mL. However, the nanoparticles were not capable of inhibiting Gram-negative bacteria (Escherichia coli) or Gram-positive bacteria (Staphylococcus aureus). Finally, an antifungal peptide (Cm-p5) from the sea animal Cenchritis muricatus (Gastropoda: Littorinidae) was conjugated to the modified manganese ferrite nanoparticles. The antifungal activity of the conjugated nanoparticles was higher than their bulk counterparts, showing a minimal inhibitory concentration of 100 µg/mL. This conjugate proved to be nontoxic to a macrophage cell line at concentrations that showed antimicrobial activity. PMID:27563243

  5. Citric acid aided synthesis, characterization, and high-rate electrochemical performance of LiNi0.5Mn1.5O4

    International Nuclear Information System (INIS)

    The citric acid aided synthesis, physico-chemical and electrochemical characterization of the nanosized nickel-doped lithium manganese spinel, LiNi0.5Mn1.5O4 having excellent high-rate properties is described. An optimal electrode material represented by perfectly shaped, well-faceted particles of 100-400 nm size containing crystallites of the 15-22 nm size could be obtained upon the thermal treatment at 700 °C. In spite of a reduced specific capacity (102 mAh·g−1) it is able to retain a half of it upon the discharge current of 4400 mA·g−1 (30 C) and to endure the current load of 5870 mAh·g−1 (40 C) delivering the reversible specific capacity of 25 mAh·g−1. It is suggested that the reduced specific capacity is determined primarily by the aggregation of material's particles, whereas the good high-rate capability is governed not only by the size of crystallites but also by the perfectness of crystals, and imperfections in big, well-shaped crystals (like dislocations, grain boundaries, etc.) less retard the diffusion of lithium ions than particle boundaries in small, randomly oriented, accreted crystals

  6. A rapid response time and highly sensitive amperometric glucose biosensor based on ZnO nanorod via citric acid-assisted annealing route

    Science.gov (United States)

    Yang, Zao; Ye, Zhizhen; Zhao, Binghui; Zong, Xiaolin; Wang, Ping

    2010-04-01

    ZnO nanorods were synthesized by citric acid-assisted annealing route. In a phosphate buffer solution with a pH value of 7.4, glucose oxidase was immobilized on the surface of ZnO nanorod through chitosan-assisted cross-linking technique. The one-dimensional ZnO nanorods provide a large effective surface area with high surface-to-volume ratio and provide a favorable environment for the immobilization of GO x. The response time of this biosensor is less than 2 s. This biosensor has a very high sensitivity of 25.7 μA cm -2 mM -1. The low detection limit was estimated to be 0.01 mM. Two linear response ranges are 0.01-0.25 mM and 0.3-0.7 mM. The Michaelis-Menten constant is found to be 1.95 mM. These results demonstrate that zinc oxide nanorods have potential applications in biosensors.

  7. Kinetics of co-crystal formation with caffeine and citric acid via liquid-assisted grinding analyzed using the distinct element method.

    Science.gov (United States)

    Shimono, Keisuke; Kadota, Kazunori; Tozuka, Yuichi; Shimosaka, Atsuko; Shirakawa, Yoshiyuki; Hidaka, Jusuke

    2015-08-30

    The kinetics of co-crystal formation of caffeine (CF) with citric acid (CTA) was evaluated. Ball milling of CF and CTA in molar ratios of 4:1, 3:1, 2:1, 1:1, 1:2, 1:3, and 1:4 was performed by the liquid-assisted grinding (LAG) method. The samples were characterized by powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC). Two types of co-crystals (co-crystal-1, a 1:1 CF-CTA co-crystal; and co-crystal-2, a new co-crystal form) were obtained. The kinetic characteristics of this new co-crystal formation were assessed by calculating the ball impact energy and force using the distinct element method (DEM) simulations. The results indicated that co-crystal-2 creation occurred under a condition in which the ball impact force exceeded a certain threshold value. Moreover, the total ball impact energy was positively correlated with co-crystal formation, exhibiting a higher ball impact force than the threshold value. The kinetics of co-crystal-2 formation was almost consistent with the Jander equation. Consequently, co-crystal-2 formation could be explained according to a three-dimensional diffusion mechanism. PMID:25998562

  8. Comparative genomics of citric-acid-producing Aspergillus niger ATCC 1015 versus enzyme-producing CBS 513.88

    DEFF Research Database (Denmark)

    Andersen, Mikael Rørdam; Salazar, Margarita Pena; Schaap, Peter J.;

    2011-01-01

    The filamentous fungus Aspergillus niger exhibits great diversity in its phenotype. It is found globally, both as marine and terrestrial strains, produces both organic acids and hydrolytic enzymes in high amounts, and some isolates exhibit pathogenicity. Although the genome of an industrial enzym...

  9. Comparative genomics of citric-acid producing Aspergillus niger ATCC 1015 versus enzyme-producing CBS 513.88

    Energy Technology Data Exchange (ETDEWEB)

    Grigoriev, Igor V.; Baker, Scott E.; Andersen, Mikael R.; Salazar, Margarita P.; Schaap, Peter J.; Vondervoot, Peter J.I. van de; Culley, David; Thykaer, Jette; Frisvad, Jens C.; Nielsen, Kristen F.; Albang, Richard; Albermann, Kaj; Berka, Randy M.; Braus, Gerhard H.; Braus-Stromeyer, Susanna A.; Corrochano, Luis M.; Dai, Ziyu; Dijck, Piet W.M. van; Hofmann, Gerald; Lasure, Linda L.; Magnusson, Jon K.; Meijer, Susan L.; Nielsen, Jakob B.; Nielsen, Michael L.; Ooyen, Albert J.J. van; Panther, Kathyrn S.; Pel, Herman J.; Poulsen, Lars; Samson, Rob A.; Stam, Hen; Tsang, Adrian; Brink, Johannes M. van den; Atkins, Alex; Aerts, Andrea; Shapiro, Harris; Pangilinan, Jasmyn; Salamov, Asaf; Lou, Yigong; Lindquist, Erika; Lucas, Susan; Grimwood, Jane; Kubicek, Christian P.; Martinez, Diego; Peij, Noel N.M.E. van; Roubos, Johannes A.; Nielsen, Jens

    2011-04-28

    The filamentous fungus Aspergillus niger exhibits great diversity in its phenotype. It is found globally, both as marine and terrestrial strains, produces both organic acids and hydrolytic enzymes in high amounts, and some isolates exhibit pathogenicity. Although the genome of an industrial enzyme-producing A. niger strain (CBS 513.88) has already been sequenced, the versatility and diversity of this species compels additional exploration. We therefore undertook whole genome sequencing of the acidogenic A. niger wild type strain (ATCC 1015), and produced a genome sequence of very high quality. Only 15 gaps are present in the sequence and half the telomeric regions have been elucidated. Moreover, sequence information from ATCC 1015 was utilized to improve the genome sequence of CBS 513.88. Chromosome-level comparisons uncovered several genome rearrangements, deletions, a clear case of strain-specific horizontal gene transfer, and identification of 0.8 megabase of novel sequence. Single nucleotide polymorphisms per kilobase (SNPs/kb) between the two strains were found to be exceptionally high (average: 7.8, maximum: 160 SNPs/kb). High variation within the species was confirmed with exo-metabolite profiling and phylogenetics. Detailed lists of alleles were generated, and genotypic differences were observed to accumulate in metabolic pathways essential to acid production and protein synthesis. A transcriptome analysis revealed up-regulation of the electron transport chain, specifically the alternative oxidative pathway in ATCC 1015, while CBS 513.88 showed significant up-regulation of genes relevant to glucoamylase A production, such as tRNA-synthases and protein transporters. Our results and datasets from this integrative systems biology analysis resulted in a snapshot of fungal evolution and will support further optimization of cell factories based on filamentous fungi.[Supplemental materials (10 figures, three text documents and 16 tables) have been made available

  10. On the interaction of uranium with the bioligands citric acid and glucose; Zur Wechselwirkung von Uran mit den Bioliganden Citronensaeure und Glucose

    Energy Technology Data Exchange (ETDEWEB)

    Steudtner, Robin

    2011-10-26

    , 591.8 nm, 513.5 nm, 537.0 nm and 561.9 nm for the 1:0:1-complex and at 483.6 nm, 502.7 nm, 524.5 nm, 548.1 and 574.0 nm for the 2:0:2-complex. The respective fluorescence lifetimes determined at 153 K were 79 {+-} 15 {mu}s (1:0:1) and 10 {+-} 3 {mu}s (2:0:2). In this work not only the model complexation of the hexavalent uranium but also the complex behaviour of the tetravalent uranium in presence of citric acid were studied. In all samples the uranium citrate complexes were detected as dissolved species. In addition to the spectroscopy detection of the new forming uranium citrate species the complex formation could be analyzed the complex formation constant and the single component spectrum for all complexes. Complex formation constant for the citrate species of the hexavalent uranium of log {beta}{sub 203} = 22.67 {+-} 0.34 ([(UO{sub 2}){sub 2}(Cit){sub 3}]{sup 5-}) and of log {beta}{sub 103} = 12.35 {+-} 0.22 ([UO{sub 2}(Cit){sub 3}]{sup 7-}) and for the complexes of the tetravalent uranium of log {beta}{sub 1-21} = -9.74 {+-} 0.23 ([U(OH){sub 2}Cit]{sup -}) und log {beta}{sub 1-31} = -20.36 {+-} 0.22 ([U(OH){sub 3}Cit]{sup 2-}) were calculated for the first time. Also to the complex behaviour and the redox behaviour of uranium in presence of citric acid were investigated. The photochemical reduction of uranium(VI) by citric acid at aerobic and anaerobic conditions was detected by UV-Vis spectroscopy. The reaction at aerobic conditions showed which unknown influence organic ligands can have on the chemical behaviour of uranium. The highest reduction rate could be determinate between pH 3.5 and 4 with 52 % at aerobic conditions and 66 % at anaerobic conditions. With increase of the pH the amount of reduced uranium(VI) decreases. In the oxygen system a reduction above pH 7 wasn't detectable. These results are in a very good correspondence with model calculation of the uranium(VI) speciation in urine.

  11. Polyelectrolyte Complexes of Low Molecular Weight PEI and Citric Acid as Efficient and Nontoxic Vectors for in Vitro and in Vivo Gene Delivery.

    Science.gov (United States)

    Giron-Gonzalez, M Dolores; Salto-Gonzalez, Rafael; Lopez-Jaramillo, F Javier; Salinas-Castillo, Alfonso; Jodar-Reyes, Ana Belen; Ortega-Muñoz, Mariano; Hernandez-Mateo, Fernando; Santoyo-Gonzalez, Francisco

    2016-03-16

    Gene transfection mediated by the cationic polymer polyethylenimine (PEI) is considered a standard methodology. However, while highly branched PEIs form smaller polyplexes with DNA that exhibit high transfection efficiencies, they have significant cell toxicity. Conversely, low molecular weight PEIs (LMW-PEIs) with favorable cytotoxicity profiles display minimum transfection activities as a result of inadequate DNA complexation and protection. To solve this paradox, a novel polyelectrolyte complex was prepared by the ionic cross-linking of branched 1.8 kDa PEI with citric acid (CA). This system synergistically exploits the good cytotoxicity profile exhibited by LMW-PEI with the high transfection efficiencies shown by highly branched and high molecular weight PEIs. The polyectrolyte complex (1.8 kDa-PEI@CA) was obtained by a simple synthetic protocol based on the microwave irradiation of a solution of 1.8 kDa PEI and CA. Upon complexation with DNA, intrinsic properties of the resulting particles (size and surface charge) were measured and their ability to form stable polyplexes was determined. Compared with unmodified PEIs the new complexes behave as efficient gene vectors and showed enhanced DNA binding capability associated with facilitated intracellular DNA release and enhanced DNA protection from endonuclease degradation. In addition, while transfection values for LMW-PEIs are almost null, transfection efficiencies of the new reagent range from 2.5- to 3.8-fold to those of Lipofectamine 2000 and 25 kDa PEI in several cell lines in culture such as CHO-k1, FTO2B hepatomas, L6 myoblasts, or NRK cells, simultaneously showing a negligible toxicity. Furthermore, the 1.8 kDa-PEI@CA polyelectrolyte complexes retained the capability to transfect eukaryotic cells in the presence of serum and exhibited the capability to promote in vivo transfection in mouse (as an animal model) with an enhanced efficiency compared to 25 kDa PEI. Results support the polyelectrolyte complex

  12. Structural, electronic and photoluminescence properties of Eu3+-doped CaYAlO4 obtained by using citric acid complexes as precursors

    Science.gov (United States)

    Perrella, R. V.; Júnior, C. S. Nascimento; Góes, M. S.; Pecoraro, E.; Schiavon, M. A.; Paiva-Santos, C. O.; Lima, H.; Couto dos Santos, M. A.; Ribeiro, S. J. L.; Ferrari, J. L.

    2016-07-01

    The search for new materials that meet the current technological demands for photonic applications, make the Rare Earth ions embedded in inorganic oxides as excellent candidates for several technological devices. This work presents the synthesis of Eu3+-doped CaYAlO4 using citric acid as ligand to form a complex precursor. The methodology used has big draw due to its easy handling and low cost of the materials. The thermal analysis of viscous solutions was evaluated and the obtained compounds show the formation of a polycrystalline tetragonal phase. Rietveld refinement was used to understand the structural and the cell parameters of the crystalline phase as a function of temperature of heat-treatment. Crystallite size and microstrain were determined and were shown to have a direct relationship with the temperature of the heat-treatment. The band-gap of the CaYAlO4 doped with 1 and 10 mol% of Eu3+ showed values close to 4.30 eV, resulting in their transparency in the visible region between 330 and 750 nm. Besides the intense photoluminescence from Eu3+, a study was conducted to evaluate the possible position of the Eu3+ in the CaYAlO4 as host lattice. Lifetime of the emission decay from Eu3+ excited state 5D0 show that CaYAlO4 is a good host to rare earth ions, once it can avoid clustering of these ions in concentration as high as 10 mol%. The predictions of the sublevels of the 7F1 crystal field level are discussed through the method of equivalent nearest neighbours (MENN). The intensity parameters (Ωλ, λ = 2 and 4) are reproduced with physically reasonable values of average polarizabilities. The set of charge factors used in both calculations are in good agreement with the charge of the europium ion described by the Batista-Longo improved model (BLIM). The quantum efficiencies of the materials were calculated based on Judd-Ofelt theory. Based on the results obtained in this work, the materials have potential use in photonic devices such as lasers and solid

  13. Effect of Phytase Superdoses and Citric Acid on Growth Performance, Plasma Phosphorus and Tibia Ash in Broilers Fed Canola Meal-Based Diets Severely Limited in Available Phosphorus

    Directory of Open Access Journals (Sweden)

    Taheri HR

    2015-06-01

    Full Text Available This experiment was conducted to investigate the effect of phytase superdoses alone or in combination with citric acid (CA in canola meal-based diets severely limited in available phosphorus (Pa on growth performance, plasma phosphorus (P, and tibia ash (TA in broilers from 22 to 42 d of age. Two hundreds and eighty 21-d-old male broilers were used in 28 pens of 10 birds per each. The experimental diets consisted of a positive control (PC diet and six negative control (NC diets which consisted of two levels of CA (0 and 20 g/Kg and three levels of phytase (0, 1000 and 4000 U/Kg in a 2 × 3 factorial arrangement. The PC diet contained 4.3 g/Kg Pa, but all NC diets contained 1.5 g/Kg Pa. Results indicated that the birds fed the PC diet had a significantly higher average daily gain (ADG, plasma P and TA, but a lower feed conversion ratio (FCR than those fed the NC diet. The ADG, FCR and plasma P values in birds fed NC diets supplemented with 4000 U/Kg phytase enzyme (with or without CA significantly reached those of birds fed the PC diet. But, addition of phytase enzyme at 1000 U/Kg only plus CA to the NC diet could significantly improve FCR and plasma P. A significant interaction was observed between phytase and CA for FCR and plasma P. Although TA values in NC + 1000 U/Kg phytase treatments (with or without CA were similar to the PC treatment, TA values of NC + 4000 U/Kg phytase treatments (with or without CA was greater than that of the PC treatment. Results of this study showed that, in severely limited Pa corn-canola meal-based diets, supplementing 4000 U/Kg phytase or also 1000 U/Kg phytase plus CA will be sufficient to obtain the comparable feed efficiency in broilers to those fed the adequate Pa diet.

  14. Research on the Behavior and Mechanism of Citric Acid and Malic Acid of Combustion under the State Cigarette Smoking%柠檬酸和苹果酸在卷烟阴燃状态下的燃烧行为和机制研究

    Institute of Scientific and Technical Information of China (English)

    王程辉; 周顺; 徐迎波; 田振峰

    2012-01-01

    [Objective] The comparative study on the behavior and mechanism of citric acid and malic acid in the smoldering combustion of cigarette was conducted.[Method] The effect of the rate of temperature-raising in combustion on the burning behavior of citric acid and malic acid in cigarette was tested with micro-combustion calorimeter ( MCC). The combustion process of the cigarette, especially for the formation rule of the gas products of major pyrolysis, was comparatively analyzed with TG-FTIR in order to explore the combustion mechanism.[Result] It was found through MCC testing that in the same combustion condition, the flammability of citric acid was better than that of malic acid, but its combustion was slightly worse than that of citric acid. The rate of temperature-raising in combustion greatly affected the burning behavior of malic acid and citric acid in cigarette. The TG-FTIR testing results showed that the burning behavior of citric acid and malic acid in cigarette mainly depended on the formation of pyrolysis products. The citric acid was relatively more susceptible to thermal decomposition than malic acid and much more H2O, CO2, CO and carbonyl compounds would be generated in the pyrolysis process.[Conclusion] The burning behavior , in which the flammability of citric acid was better than that of malic acid and its combustion was slightly worse than that of citric acid, was determined because of the relatively weak stability of pyrolysis and the relative composition of un-flammable gas and flammable gas in initial period.%[目的]比较研究柠檬酸和苹果酸在卷烟阴燃状态下的燃烧行为和机制.[方法]利用微燃烧量热仪(MCC)考察升温速率对柠檬酸和苹果酸燃烧行为的影响;利用热重-红外联用仪(TG-FTIR)比较研究其燃烧过程,特别是主要热解气相产物的形成规律,探讨其燃烧机理.[结果] MCC测试结果发现,在相同的燃烧条件下,柠檬酸的易燃性优于苹果酸,但燃烧性稍差

  15. Synthesis of aqueous ferrofluids of Zn{sub x}Fe{sub 3-x}O{sub 4} nanoparticles by citric acid assisted hydrothermal-reduction route for magnetic hyperthermia applications

    Energy Technology Data Exchange (ETDEWEB)

    Behdadfar, Behshid, E-mail: bbehdadfar@ma.iut.ac.ir [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Kermanpur, Ahmad [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Sadeghi-Aliabadi, Hojjat [School of Pharmacy, Isfahan Pharmaceutical Research Center, Isfahan University of Medical Sciences, Isfahan (Iran, Islamic Republic of); Morales, Maria del Puerto [Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, 28049 Madrid (Spain); Mozaffari, Morteza [Department of Physics, Razi University, Kermanshah (Iran, Islamic Republic of)

    2012-07-15

    Superparamagnetic and monodispersed aqueous ferrofluids of Zn substituted magnetite nanoparticles (Zn{sub x}Fe{sub 3-x}O{sub 4}, x=0, 0.25, 0.3, 0.37 and 0.4) were synthesized via hydrothermal-reduction route in the presence of citric acid, which is a facile, low energy and environmental friendly method. The synthesized nanoparticles were characterized by X ray diffraction (XRD) analysis, Fourier transform infrared (FTIR) spectroscopy, scanning and transmission electron microscopy (SEM and TEM) and the dynamic light scattering (DLS) method. The results showed that a certain amount of citric acid was required to obtain single phase Zn substituted magnetite nanoparticles. Citric acid acted as a modulator and reducing agent in the formation of spinel structure and controlled nanoparticle size and crystallinity. Mean particle sizes of the prepared nanoparticles were around 10 nm. The results that are obtained from XRD, magnetic and power loss measurements showed that the crystallinity, saturation magnetization (M{sub S}) and loss power of the synthesized ferrofluids were all influenced by the substitution of Zn in the structure of magnetite. The Zn substituted magnetite nanoparticles obtained by this route showed a good stability in aqueous medium (pH 7) and hydrodynamic sizes below 100 nm and polydispersity indexes below 0.2. The calculated intrinsic loss power (ILP) for the sample x=0.3 (e.g. 2.36 nH m{sup 2}/kg) was comparable to ILP of commercial ferrofluids with similar hydrodynamic sizes. - Highlights: Black-Right-Pointing-Pointer We synthesized Zn substituted magnetite nanoparticles via hydrothermal-reduction route. Black-Right-Pointing-Pointer We used citric acid as a reducing agent in this route. Black-Right-Pointing-Pointer This route is a facile, low energy and environmental friendly method. Black-Right-Pointing-Pointer The nanoparticles obtained by this route were superparamagnetic and stable in water. Black-Right-Pointing-Pointer The calculated intrinsic

  16. Identification of a Classical Mutant in the Industrial Host Aspergillus niger by Systems Genetics: LaeA Is Required for Citric Acid Production and Regulates the Formation of Some Secondary Metabolites

    DEFF Research Database (Denmark)

    Niu, Jing; Arentshorst, Mark; Nair, P. Deepa S.;

    2015-01-01

    The asexual filamentous fungus Aspergillus niger is an important industrial cell factory for citric acid production. In this study, we genetically characterized a UV-generated A. niger mutant that was originally isolated as a nonacidifying mutant, which is a desirable trait for industrial enzyme...... with high-throughput genome sequencing to identify the mutation responsible for the nonacidifying phenotype. Since A. niger has no sexual cycle, parasexual genetics was used to generate haploid segregants derived from diploids by loss of whole chromosomes. We found that the nonacidifying phenotype was...

  17. Respiratory activity and pigment metabolism in fresh-cut beet roots treated with citric acid Atividade respiratória e metabolismo dos pigmentos de beterrabas minimamente processadas tratadas com ácido cítrico

    OpenAIRE

    Ricardo A. Kluge; Maria Carolina D Vitti; Fabiana F Sasaki; Angelo P Jacomino; Celso L. Moretti

    2008-01-01

    Beet roots cv. Early Wonder were graded for firmness, color and size, and were peeled inside a cold room (10ºC). Roots were then shredded (2 mm thick), sanitized for 6 minutes (NaClO/200 mg L-1), rinsed and centrifuged. Fresh-cut beet roots were then treated for 5 minutes with citric acid in the following concentrations: 0 (control), 500; 1,000; 1,500 and 2,000 mg L-1. The material was centrifuged again, placed in trays, wrapped with PVC plastic film, and stored at 5ºC and 85-90% HR for 10 da...

  18. Identification of a classical mutant in the industrial host Aspergillus niger by systems genetics: LaeA is required for citric acid production and regulates the formation of some secondary metabolites

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jing; Arentshorst, Mark; Nair, Deepa; Dai, Ziyu; Baker, Scott E.; Frisvad, Jens; Nielsen, Kristian F.; Punt, Peter J.; Ram, Arthur F.

    2016-01-11

    Rapid acidification of the culture medium by the production of organic acids and the production of acid-induced proteases are key characteristics of the filamentous fungus Aspergillus niger. The D15 mutant of A. niger is non-acidifying mutant and used often for the expression of recombinant proteins in A. niger, because of its reduced production of extracellular proteases under non-acidic conditions. In this study, the D15 mutant is characterized in detail. Strongly reduced levels of citric and oxalic acid were observed in the D15 mutant both in shake flask cultures and in controlled batch cultivations. To identify the mutation in the D15 mutant, we successfully combined high-throughput sequencing (Illumina) with bulk segregant analysis. Because of the lack of a sexual cycle for A. niger, the parasexual cycle was used to generate a pool of segregants. From the 52 single nucleotide polymorphisms (SNPs) between the parental strains, three SNPs were homozygous in the genomic DNA of pool of segregants. These three SNPs mapped to all the right arm of chromosome II, indicating that this region contains the genetic locus affecting the phenotype related to acid production. Of the three SNPs, one mutation resulted in a missense mutation in the gene encoding the A. niger homologue of the A. nidulans methyltransferase gene laeA. Complementation analysis of the original mutant with the laeA gene and targeted disruption of laeA further confirmed that LaeA is involved in citric acid production in A. niger lab (N402) and citric acid production strains (ATCC 11414). Analysis of the secondary metabolite (SM) profile of the laeA mutants indicate that LaeA is required for the production of several SMs (asperrubrol, atromentin and JBIR86), but deletion of laeA also resulted in the presence of SMs (aspernigrin A/B and BMS-192548) that were not detected in the wild-type strain. The levels of ten other SMs were not strongly affected as a result of laeA deletion indicating that only a

  19. Transglutaminase-induced or citric acid-mediated cross-linking of whey proteins to tune the characteristics of subsequently desolvated sub-micron and nano-scaled particles.

    Science.gov (United States)

    Bagheri, Leila; Yarmand, Mohammadsaeed; Madadlou, Ashkan; Mousavi, Mohammad E

    2014-01-01

    Whey proteins were inter-connected either by the enzyme transglutaminase or citric acid and then desolvated with ethanol to generate particles. Both samples comprised of sub-micron (>300 nm) and nano-scaled (~100 nm) particles based on the hydrodynamic size measurements. Enzyme-induced cross-linking of proteins yielded more monodisperse particles and decreased the mean size of the major (nano-scaled) fraction of particles. Scanning electron microscopy images revealed a spherical morphology for all samples with mean sizes of Atomic force microscopy indicated a lower height for the particles from enzymatically cross-linked proteins. The mediating role of citric acid in bridging the proteins was confirmed by Fourier transform infrared spectroscopy. Differential scanning calorimetry indicated that pre-heating of protein solution before cross-linking and desolvation denatured the proteins entirely. In vitro degradation of whey protein particles in a simulated gastric fluid demonstrated that cross-linking of whey proteins before desolvation stage enhanced significantly the digestion stability of particles. PMID:24766206

  20. Effects of pH and citric acid content on the structure and magnetic properties of MnZn ferrite nanoparticles synthesized by a sol–gel autocombustion method

    International Nuclear Information System (INIS)

    MnZn ferrite nanoparticles have been synthesized by a sol–gel autocombustion technique with different pHs of 0, 5 and 7 and different citric acid to metal nitrate (CA/MN) molar ratios of 0.25, 0.5 and 1. The crystallite size, microstructure and magnetic properties were studied using X-ray diffraction, scanning electron microscopy and vibrating sample magnetometry methods. The results showed that the single phase MnZn ferrite could be achieved directly without any post-calcination using pH of 7 and CA/MN molar ratio of 0.5. MnZn ferrite nanoparticles prepared by pH=7 and CA/MN=0.5 with the crystallite size of 39 nm exhibited saturation magnetization of 20.9 emu/g and coercivity of 44 Oe. - Highlights: • MnZnFe2O4 nanoparticles were synthesized by the sol–gel autocombustion technique at different pHs and citric acid to metal nitrate (CA/MN) molar ratios. • The single phase MnZn ferrite was achieved directly without any post-calcination using pH=7 and CA/MN molar ratio=0.5. • Single phase nanoparticles exhibited partially inverse spinel structures. • Magnetization was correlated to the inversion factor and crystallite size

  1. Anaerobic waste water treatment: influencing parameters on the acid formation of citric acid production waste - investigation in lab scale and on a large treatment plant

    International Nuclear Information System (INIS)

    Based on the biochemical background of anaerobic waste water treatment processes and on the kinetic criteria the problems of acid formation in one and two stage fermentations are discussed. Chemical analytics play an important role on the control of anaerobic processes. In a separate chapter the significance of different parameters and their application for the control of acidification processes is discussed. Of special importance is an early information on process disturbances and considerations concerning the balancing of the relevant processes. Analytical problems that occur in practice are also dealt with. The practical experience with the large scale wastewater treatment plant, where the described procedures were applied are the main purpose of the thesis. The main influencing parameters on both the lab scale and large scale processes are compared and the influence of important process variables like temperature, pH, load, waste water composition and addition of aerobic and anaerobic sludges on the acid formation is investigated. The results of the work are discussed and compared with results from the literature. In addition a mathematical model dealing with the main pH-dependent equilibrium conditions for acidification reactions was developed on basis of existing models for anaerobic waste water treatment processes. (author)

  2. Determinação simultânea dos ácidos orgânicos tartárico, málico, ascórbico e cítrico em polpas de acerola, açaí e caju e avaliação da estabilidade em sucos de caju Simulataneous determination of tartaric, malic, ascorbic and citric acids in acerola, açai and cashew pulps, and stability evaluation in cashew juices

    Directory of Open Access Journals (Sweden)

    Rodrigo Scherer

    2008-01-01

    Full Text Available The aim of the present study was determining the main organic acids in pulp and juices, as well as evaluating their stability, after opening the package, by liquid chromatography in a C18 column with isocratic elution and UV detection. In açaí pulp tartaric, malic and citric acids were found. Cashew samples presented all of the organic acids evaluated, besides high concentrations of ascorbic and malic acids. Acerola pulp had the highest ascorbic acid concentration. A small decrease in organic acid content during storage was observed. Malic and citric acids seem to be more stable than tartaric and ascorbic acids.

  3. Validation of a lactic acid- and citric acid-based antimicrobial product for the reduction of Escherichia coli O157: H7 and Salmonella on beef tips and whole chicken carcasses.

    Science.gov (United States)

    Laury, A M; Alvarado, M V; Nace, G; Alvarado, C Z; Brooks, J C; Echeverry, A; Brashears, M M

    2009-10-01

    The objectives of this study were to determine the effects of a lactic acid- and citric acid-based antimicrobial product on the reduction of Salmonella on whole broiler carcasses during processing and the reduction of Salmonella and Escherichia coli O157:H7 on beef trim. Freshly harvested broiler carcasses were inoculated with an inoculum of Salmonella strains to yield a 10(5) CFU/ml pathogen load on the surface of the carcass. The beef tips were inoculated as well with an inoculum of either E. coli O157:H7 or Salmonella to yield 10(4) CFU/100 cm(2). After 30 min for attachment, the broiler carcasses were treated with Chicxide applied for 5 s via a spray or immersed in Chicxide for 5, 10, or 20 s. Broiler carcasses were rinsed in poultry rinse bags with 400 ml of Butterfield's phosphate buffer in which Salmonella was enumerated from the diluents and Butterfield's phosphate. Chicxide significantly reduced Salmonella by 1.3 log CFU/ml with spray treatment and 2.3 log CFU/ml for all dip treatments. Following 30 min of attachment, the beef tips were placed into a spray cabinet with either Beefxide or sterilized water (control) and sprayed at 1 ft/2.5 s chain speed at 40 lb/in(2). The external surface of each beef tip was swabbed (100 cm(2)) to determine pathogen loads. Beefxide significantly reduced E. coli O157:H7 by 1.4 log CFU/100 cm(2) and Salmonella by 1.1 log CFU/100 cm(2) (P < 0.05) compared with the control samples. PMID:19833048

  4. Indução da fitoextração de chumbo por ácido cítrico em solo contaminado por baterias automotivas Citric acid enhances lead phytoextraction from a soil contaminated by automotive batteries

    Directory of Open Access Journals (Sweden)

    Eriberto Vagner de Souza Freitas

    2009-04-01

    to their biodegradability. The study aimed at evaluating the performance of single and split applications of citric acid on enhancing Pb extraction by maize plants (Zea mays grown in soil samples from an area contaminated with Pb from battery wastes. The citric acid was applied at concentrations of 0, 20, 40, 60, and 80 mmol kg-1, either in a single dose on the30th day of growth or split in two, on the 30th and 34th day. Soil samples were subjected to chemical extraction by CaCl2 and fractionation. Results showed that splitting the citric acid doses did not improve the effectiveness of phytoextraction. A single application is therefore more suitable for Pb accumulation in plants. Enhanced phytoextraction using citric acid is feasible in a relatively short term and with no secondary problems due to Pb leaching. Citric acid amendment mobilized Pb from the least soluble fractions (bound to organic matter and iron oxides into the exchangeable form. The distribution pattern of Pb in soil fractions treated with citric acid followed the order: exchangeable > organic matter > crystalline iron oxide > amorphous iron oxide.

  5. Improved electrochemical performance of LiNi0.6Co0.2Mn0.2O2 cathode material synthesized by citric acid assisted sol-gel method for lithium ion batteries

    Science.gov (United States)

    Lee, Suk-Woo; Kim, Hyungsub; Kim, Myeong-Seong; Youn, Hee-Chang; Kang, Kisuk; Cho, Byung-Won; Roh, Kwang Chul; Kim, Kwang-Bum

    2016-05-01

    A citric acid assisted sol-gel method is employed for synthesizing LiNi0.6Co0.2Mn0.2O2 for use as a cathode material in lithium-ion batteries. The effects of heat-treatment temperature and oxygen atmosphere on the structural and electrochemical properties of LiNi0.6Co0.2Mn0.2O2 are investigated, in order to determine optimal conditions for the synthesis of LiNi0.6Co0.2Mn0.2O2 via the citric acid assisted sol-gel method. In particular, the presence of oxygen in the atmosphere effectively leads to a decrease in the degree of cation mixing and the formation of LiOH and Li2CO3 on the surface of LiNi0.6Co0.2Mn0.2O2. Furthermore, heat-treatment in an oxygen atmosphere improves the uniformity of oxidation state of Ni ions between the surface and bulk. LiNi0.6Co0.2Mn0.2O2 synthesized by heat-treatment at 850 °C under an oxygen atmosphere shows a discharge capacity of 174 mA h g-1 and 89% capacity retention after 100 cycles. In addition, it shows high rate capability (i.e., 41% capacity retention at 10 C), which is an improved rate performance over a previous report. The results of this study should provide useful information for the synthesis of Ni-rich layered oxides for lithium ion batteries.

  6. Respiratory activity and pigment metabolism in fresh-cut beet roots treated with citric acid Atividade respiratória e metabolismo dos pigmentos de beterrabas minimamente processadas tratadas com ácido cítrico

    Directory of Open Access Journals (Sweden)

    Ricardo A Kluge

    2008-12-01

    Full Text Available Beet roots cv. Early Wonder were graded for firmness, color and size, and were peeled inside a cold room (10ºC. Roots were then shredded (2 mm thick, sanitized for 6 minutes (NaClO/200 mg L-1, rinsed and centrifuged. Fresh-cut beet roots were then treated for 5 minutes with citric acid in the following concentrations: 0 (control, 500; 1,000; 1,500 and 2,000 mg L-1. The material was centrifuged again, placed in trays, wrapped with PVC plastic film, and stored at 5ºC and 85-90% HR for 10 days. Every two days, treatments were analyzed for respiratory activity and betacyanin and betaxanthin contents. The application of citric acid caused the reduction of respiratory rate in the fresh-cut tissue. In the second day of storage, control showed the highest respiratory activity among treatments, reaching around 77 mL CO2 kg-1 h-1. Citric acid solution dips in a concentration higher than 500 mg L-1 contributed to a decrease in respiratory activity and no peak in CO2 evolution was observed. There were significant differences among all treatments during the storage period for the contents of betacyanin, which were around 40; 45; 48; 51 and 55 mg 100 g-1 for the fresh-cut material treated with 0; 500; 1,000; 1,500 and 2,000 mg L-1 of citric acid, respectively.Also, levels of betaxanthin were around 25; 29; 33; 35 and 39 mg 100 g-1 for the material treated with 0; 500; 1,000; 1,500 and 2,000 mg L-1 of citric acid, respectively. The application of citric acid after minimal processing apparently have the ability to reduce respiratory rate and the degradation of pigments, which contributes to extend the shelf life of the fresh-cut product.Beterrabas 'Early Wonder' foram selecionadas quanto à firmeza, cor e tamanho e descascadas em câmara fria (10ºC. As raízes foram cortadas (2 mm de espessura, sanitizadas, enxaguadas e centrifugadas. As beterrabas foram tratadas com ácido cítrico nas concentrações: 0 (controle, 500; 1000; 1500 e 2000 mg L-1. O produto

  7. Dissolution of Kaolinite Induced by Citric Acids, Oxalic Acids and Malic Acids in HAC-NH4AC Buffer Solution%醋酸-醋酸铵缓冲体系中柠檬酸、草酸和苹果酸对高岭石的溶解特征

    Institute of Scientific and Technical Information of China (English)

    胡华锋; 王兴祥; 介晓磊; 李清曼

    2013-01-01

    采用间歇法(batch method)模拟研究醋酸-醋酸铵缓冲体系中柠檬酸、草酸和苹果酸三种低分子量有机酸对高岭石的溶解特征.结果表明:柠檬酸、草酸和苹果酸三种有机酸均能显著促进高岭石的溶解,溶解能力都是随其浓度和酸度的升高而增强;当有机酸浓度为1 mmol/L,pH3.5时,草酸>柠檬酸>苹果酸;pH5.5和pH4.5时,柠檬酸>草酸>苹果酸;而当有机酸浓度≥5 mmol/L时,草酸>柠檬酸>苹果酸,且对高岭石的溶解能力都大于无机酸.当柠檬酸、草酸和苹果酸浓度为1mmol/L时,反应级数(nHL)分别为0.09、0.27和0.18,速率常数(kHL)分别为4.03×10-13、2.62×10-12和4.73×10-13;当其浓度为5mmol/L时,其反应级数(nHL)分别为0.16、0.37和0.16,速率常数(kHL)分别为1.38×10-12、2.32×10-11和4.97×10-13;其浓度为10 mmol/L时,反应级数(nHL)分别为0.18、0.34和0.16,速率常数(kHL)分别为2.17×10-12、2.60×10-11和6.05×10-13.对于柠檬酸和草酸而言,在促进高岭石溶解的作用上,相对于质子,配体的贡献是主要的;而对于苹果酸而言,配体的贡献是次要的.配体促进溶解速率(RL)可以用配体浓度的指数形式来表示.对柠檬酸、草酸和苹果酸而言,pH5.5时,分别为RL=10-13.01[配体]0.23、RL=10-13.28[配体]0.70和RL=10-13.72[配体]0.38;pH4.5时,分别为RL=10-13.00[配体]0.51、RL=10-13.03[配体]1.05和RL=10-14.07[配体]0.77;pH3.5时,分别为RL=10-12.99[配体]0.64、RL=10-12.72[配体]0.89和RL=10-14.61[配体]1.69.%Experiments were conducted to investigate the dissolution characteristics of kaolinite induced by three kinds of lowmolecular-weight organic acids (LOAs) (citric acids,oxalic acids and malic acids) with the batch method in HAC-NH4AC buffer solution.The results showed that LOAs enhanced significantly the solubility of kaolinite,The solubility of kaolinite was enhanced with an increase in the concentration and acidity of citric acids

  8. Effects of Citric Acid Treatment on Vitro Browning of Pomegranate Pericarp%柠檬酸处理对石榴果皮离体褐变的影响

    Institute of Scientific and Technical Information of China (English)

    冯立娟; 尹燕雷; 杨雪梅; 武冲; 孙立平

    2015-01-01

    除率均高于对照,以2%柠檬酸处理的最高,与对照差异极显著(P<0.01)。相关性分析表明,果皮褐变度与失重率、平均散失速率均为极显著正相关,与 PPO活性、总酚含量均为极显著负相关。失重率与平均散失速率均为极显著正相关,与PPO活性、总酚含量均为极显著负相关。平均散失速率与总酚含量均为极显著负相关,与 PPO 活性、DPPH 自由基清除率均为显著负相关。PPO活性与总酚含量均呈极显著正相关; POD活性与总酚含量均呈显著负相关;总酚含量与 DPPH自由基清除率均呈显著正相关。‘泰山三白酸’离体果皮较‘泰山三白甜’抗褐变,这可能与风味酸甜或品种自身特性有关。【结论】不同浓度柠檬酸处理均能降低石榴果皮中褐变度、失重率、平均散失速率、PPO 和POD活性,抑制总酚含量的降低,维持其抗氧化能力,延缓果实褐变进程,以2%柠檬酸处理的抑制效果最佳。%[Objective]This study investigated the effect of citric acid treatment on the browning of vitro pomegranate pericarp to provide the technical support for anti-browning of pomegranates. [Method]In this study,two pomegranate varieties,Taishansanbaitian and Taishansanbaisuan, were used as materials to investigate the effects of citric acid treatment on the browning of pomegranate pericarp during storage by measuring relevant physiological indexes,such as browning degree,weightlessness rate,average loss rate,PPO activity,POD activity,total phenols and DPPH (1,1-Diphenyl-2-picrylhydrazyl) radical scavenging activity,with weighing method and ultraviolet spectrophotometry.[Result]The result indicated that browning degree and weightlessness rate of the two pomegranate cultivars pericarp increased with prolonging of storage,and the peak value occurred at the12th day. The change trends of the average loss rate were different in the two pomegranate cultivars pericarp. Under control,1% and 2

  9. Demineralization effect of EDTA, EGTA, CDTA and citric acid on root dentin: a comparative study Efeito do EDTA, EGTA, CDTA e ácido cítrico na desmineralização da dentina radicular: estudo comparativo

    Directory of Open Access Journals (Sweden)

    Simone Maria Galvão Sousa

    2005-09-01

    Full Text Available The purpose of this study was to biochemically compare the decalcifying effects of 1% EDTA (pH 7.4, 1% EGTA (pH 7.4, 1% CDTA (pH 7.4, 1% citric acid solutions (pH 1.0 and 7.4 and saline solution (control on root dentin. Forty-eight single-rooted teeth were used in this study. The canals were instrumented by the step-back technique and the roots were randomly divided into six equal experimental groups (n = 8 according to the irrigating agent tested. A total of 30 µL of each solution was pipetted into the root canal and allowed to set undisturbed for 5 minutes. After this time, 15 µL of the solutions were removed from each canal using a Hamilton syringe and placed in a container with 5 mL of deionised water. The µg/mL concentration of calcium ion (Ca2+ extracted from the root canal samples was determined using inductively coupled plasma-atomic emission spectrometry (ICP-AES. Data were analysed by means of the Kruskal-Wallis and Mood's median tests. Citric acid solution at pH 1.0 removed more calcium than at pH 7.4 and than the other chelating solutions tested (p 0.05. These results indicate that citric acid at pH 1.0 is a good alternative as an irrigating solution to remove the smear layer and facilitate the biomechanical procedures.Este trabalho teve como objetivo comparar o efeito desmineralizante do EDTA (pH 7,4, EGTA (pH 7,4, CDTA (pH 7,4, ácido cítrico (pH 1,0 e 7,4 e da solução salina (controle sobre a dentina radicular. Todas as soluções teste foram preparadas na concentração de 1%. Quarenta e oito dentes unirradiculares recém-extraídos foram utilizados neste experimento. Após a instrumentação dos canais radiculares pela técnica "step-back", as raízes foram aleatoriamente divididas em 6 grupos experimentais (n = 8 de acordo com a solução teste utilizada na irrigação final. Em cada grupo, 30 µL da solução teste foram pipetados no interior de cada canal radicular e mantidos estáveis por 5 minutos. Decorrido esse per

  10. The effect of dual complexing agents of lactic and citric acids on the formation of sol-gel derived Ag–PbTiO{sub 3} percolative thin film

    Energy Technology Data Exchange (ETDEWEB)

    Su, Yanbo; Hu, Tao; Tang, Liwen; Weng, Wenjian; Han, Gaorong; Ma, Ning; Du, Piyi, E-mail: dupy@zju.edu.cn

    2014-05-02

    Controlling the formation of conductive particles to be nano-scale is important for achieving percolation effect in metal dispersed thin film composite to contribute extraordinary dielectric properties required for miniaturization of electronic devices. In this paper, lactic acid (LA) and citric acid (CA) were used as dual complexing agents to prepare a typical Ag nanoparticle dispersed PbTiO{sub 3} (PTO) composite thin film by using a sol-gel method. The phase structure of the thin film and the coordination effect between complexing agent and metallic ions were investigated. It revealed that LA coordinated with Ti{sup 4+} and Pb{sup 2+} and CA coordinated with Ag{sup +}. Lead was fixed inside the gel network by LA and restricted to evaporate during heat treatment thus the pyrochlore phase was prevented from forming in the thin film. Ag{sup +} was coordinated by CA and the diffusion and thus aggregation of silver during gelation and annealing process were weakened. Silver nanoparticles dispersed in the PTO matrix formed with dual complexing agents of LA and CA introduced during the preparation process. The composite thin film of perfect perovskite phase with silver nanoparticles embedded was obtained at the molar ratio of LA/lead = 0.5 and CA/lead = 0.5. The dielectric constant of the thin film with silver nanoparticles is 5 times higher than that without silver nanoparticles. - Highlights: • Ag nanoparticle–PbTiO{sub 3} percolative film with high dielectric property is prepared. • Evaporation of lead was prevented by coordinating Pb with lactic acid agent. • Dual complexing agents contribute block and pinning effects to form Ag nanoparticles.

  11. GITT studies on oxide cathode LiNi1/3Co1/3Mn1/3O2 synthesized by citric acid assisted high-energy ball milling

    Indian Academy of Sciences (India)

    Weidong Zheng; Miao Shui; Jie Shu; Shan Gao; Dan Xu; Liangliang Chen; Lin Feng; Yuanlong Ren

    2013-06-01

    Layered LiNi1/3Co1/3Mn1/3O2 was synthesized by a citric acid assisted solid-state method. The structure and electrochemical properties of the LiNi1/3Co1/3Mn1/3O2 materials were investigated. XRD analysis indicated the as-synthesized LiNi1/3Co1/3Mn1/3O2 was with the layered -NaFeO2 structure. The discharge capacity was about 154 m.Ahg-1 at 0.1 °C rate in the range of 2.0–4.5 V. The kinetics of the LiNi1/3Co1/3Mn1/3O2 materials was investigated by the galvanostatic intermittent titration technique (GITT) method. The lithium ion diffusion coefficient of the LiNi1/3Co1/3Mn1/3O2 was determined in the range of 10-8−10-9 cm2.s-1 as a function of voltage of 3.7−4.5 V.

  12. Scientific Opinion on the safety evaluation of the active substances citric acid (E330 and sodium hydrogen carbonate (E500ii, used as carbon dioxide generators, together with liquid absorbers cellulose and polyacrylic acid sodium salt crosslinked, in active food contact materials

    Directory of Open Access Journals (Sweden)

    EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF

    2013-04-01

    Full Text Available This scientific opinion of EFSA Panel on food contact materials, enzymes, flavourings and processing aids deals with the safety evaluation of the mixture of the active substances citric acid (E330, CAS No 77-92-9, FCM Substance No 139 and sodium hydrogen carbonate (E500ii, CAS No 144-55-8, FCM Substance No 21, which is intended to be used as a carbon dioxide generator in liquid absorbent pads in the packaging of fresh or frozen meat, poultry, fish, fruits and vegetables. Depending on absorption capacity needed, pure cellulose or a mixture of cellulose and polyacrylic acid sodium salt crosslinked may be used as absorber. The Panel noted that if the active substances are used not in direct contact with food, but are placed in a pad under conditions where its absorption capacity is not exceeded, then no migration is to be expected and therefore no exposure from the consumption of the packed food is expected. Therefore the CEF Panel concluded that the use of the mixture of the active substances citric acid (E330 and sodium hydrogen carbonate (E500ii, as carbon dioxide generator in liquid absorbent pads in the packaging of food such as fresh or frozen meat, poultry, fish, fruits and vegetables, does not raise a safety concern. The absorbent pads should be used only under conditions in which the liquid absorption capacity is not exceeded and direct contact between the substance and the food is excluded.

  13. Genome-scale reconstruction and in silico analysis of the Ralstonia eutropha H16 for polyhydroxyalkanoate synthesis, lithoautotrophic growth, and 2-methyl citric acid production

    Directory of Open Access Journals (Sweden)

    Kim Tae

    2011-06-01

    Full Text Available Abstract Background Ralstonia eutropha H16, found in both soil and water, is a Gram-negative lithoautotrophic bacterium that can utillize CO2 and H2 as its sources of carbon and energy in the absence of organic substrates. R. eutropha H16 can reach high cell densities either under lithoautotrophic or heterotrophic conditions, which makes it suitable for a number of biotechnological applications. It is the best known and most promising producer of polyhydroxyalkanoates (PHAs from various carbon substrates and is an environmentally important bacterium that can degrade aromatic compounds. In order to make R. eutropha H16 a more efficient and robust biofactory, system-wide metabolic engineering to improve its metabolic performance is essential. Thus, it is necessary to analyze its metabolic characteristics systematically and optimize the entire metabolic network at systems level. Results We present the lithoautotrophic genome-scale metabolic model of R. eutropha H16 based on the annotated genome with biochemical and physiological information. The stoichiometic model, RehMBEL1391, is composed of 1391 reactions including 229 transport reactions and 1171 metabolites. Constraints-based flux analyses were performed to refine and validate the genome-scale metabolic model under environmental and genetic perturbations. First, the lithoautotrophic growth characteristics of R. eutropha H16 were investigated under varying feeding ratios of gas mixture. Second, the genome-scale metabolic model was used to design the strategies for the production of poly[R-(--3hydroxybutyrate] (PHB under different pH values and carbon/nitrogen source uptake ratios. It was also used to analyze the metabolic characteristics of R. eutropha when the phosphofructokinase gene was expressed. Finally, in silico gene knockout simulations were performed to identify targets for metabolic engineering essential for the production of 2-methylcitric acid in R. eutropha H16. Conclusion The

  14. Morphological development of Aspergillus niger in submerged citric acid fermentation as a function of the spore inoculum level. Application of neural network and cluster analysis for characterization of mycelial morphology

    Directory of Open Access Journals (Sweden)

    Mattey Michael

    2006-01-01

    Full Text Available Abstract Background Although the citric acid fermentation by Aspergillus niger is one of the most important industrial microbial processes and various aspects of the fermentation appear in a very large number of publications since the 1950s, the effect of the spore inoculum level on fungal morphology is a rather neglected area. The aim of the presented investigations was to quantify the effects of changing spore inoculum level on the resulting mycelial morphology and to investigate the physiology that underlines the phenomena. Batch fermentations were carried out in a stirred tank bioreactor, which were inoculated directly with spores in concentrations ranging from 104 to 109 spores per ml. Morphological features, evaluated by digital image analysis, were classified using an artificial neural network (ANN, which considered four main object types: globular and elongated pellets, clumps and free mycelial trees. The significance of the particular morphological features and their combination was determined by cluster analysis. Results Cell volume fraction analysis for the various inoculum levels tested revealed that by rising the spore inoculum level from 104 to 109 spores per ml, a clear transition from pelleted to dispersed forms occurs. Glucosamine formation and release by the mycelium appears to be related to spore inoculum level. Maximum concentrations detected in fermentations inoculated with 104 and 105 spores/ml, where pellets predominated. At much higher inoculum levels (108, 109 spores/ml, lower dissolved oxygen levels during the early fermentation phase were associated with slower ammonium ions uptakes and significantly lower glucosamine concentrations while the mycelium developed in dispersed morphologies. A big increase in the main and total hyphal lengths and branching frequency was observed in mycelial trees as inoculum levels rise from 104 to 109 spores/ml, while in aggregated forms particle sizes and their compactness decreased

  15. Radiation sensitivity of different citric pectins

    Energy Technology Data Exchange (ETDEWEB)

    Inamura, Patricia Y.; Mastro, Nelida L. del [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)]. E-mails: patyoko@yahoo.com; nlmastro@ipen.br

    2007-07-01

    Pectic substances are important soluble polysaccharides of plant origin of considerable interest for food industry as gelling agent and stabilizer in jams, fruit jellies, yogurt drinks and lactic acid beverages. Polysaccharides can be degraded by ionizing radiation due to the free radical induced scission of the glycosidic bonds. Viscosity methods had been used to determine the efficiency of hydroxyl radical induced chain breaks generation in macromolecules. In the present work samples of pectin with different degree of methoxylation were employed in order to study their radiation sensitivity by means of viscosity measurements. Samples of citric pectin 1% solutions were irradiated with gamma rays at different doses, ranging from 0 to 15 kGy, using a {sup 60}Co Gammacell 220 (AECL), dose rate about 2 kGy/h. After irradiation the viscosity was measured on the viscometer Brookfield model LV-DVIII at 50, 60 and 70 deg C within a period of 48h. Pectin viscosity with high degree of methoxylation decreased sharply with the radiation dose remaining almost constant from 10 kGy. Pectin with low degree of methoxylation presented initially higher values of viscosity and the radiation induced decrease was also pronounced. Viscosity measurements decreased with the increase of the temperature applied for both kind of samples. The effect of radiation induced chain breaks generation in pectin molecules was evident through the viscosity reduction of irradiated pectin solutions although the viscosity presented diverse values depending of the degree of methoxylation of carboxyl groups in the backbone of polysaccharide macromolecules. (author)

  16. Radiation sensitivity of different citric pectins

    International Nuclear Information System (INIS)

    Pectic substances are important soluble polysaccharides of plant origin of considerable interest for food industry as gelling agent and stabilizer in jams, fruit jellies, yogurt drinks and lactic acid beverages. Polysaccharides can be degraded by ionizing radiation due to the free radical induced scission of the glycosidic bonds. Viscosity methods had been used to determine the efficiency of hydroxyl radical induced chain breaks generation in macromolecules. In the present work samples of pectin with different degree of methoxylation were employed in order to study their radiation sensitivity by means of viscosity measurements. Samples of citric pectin 1% solutions were irradiated with gamma rays at different doses, ranging from 0 to 15 kGy, using a 60Co Gammacell 220 (AECL), dose rate about 2 kGy/h. After irradiation the viscosity was measured on the viscometer Brookfield model LV-DVIII at 50, 60 and 70 deg C within a period of 48h. Pectin viscosity with high degree of methoxylation decreased sharply with the radiation dose remaining almost constant from 10 kGy. Pectin with low degree of methoxylation presented initially higher values of viscosity and the radiation induced decrease was also pronounced. Viscosity measurements decreased with the increase of the temperature applied for both kind of samples. The effect of radiation induced chain breaks generation in pectin molecules was evident through the viscosity reduction of irradiated pectin solutions although the viscosity presented diverse values depending of the degree of methoxylation of carboxyl groups in the backbone of polysaccharide macromolecules. (author)

  17. Assessment of the Effectiveness of Silver-Coated Dressing, Chlorhexidine Acetate (0.5%), Citric Acid (3%), and Silver Sulfadiazine (1%) for Topical Antibacterial Effects Against the Multi-Drug Resistant Pseudomonas Aeruginosa Infecting Full-Skin Thickness Burn Wounds on Rats

    OpenAIRE

    Yabanoglu, Hakan; Basaran, Ozgur; Aydogan, Cem; Azap, Ozlem Kurt; Karakayali, Feza; Moray, Gokhan

    2013-01-01

    The aim of this study was to compare the effects of four different topical antimicrobial dressings on a multi-drug resistant Pseudomonas aeruginosa contaminated full-thickness burn wound rat model. A total of 40 adult male Wistar albino rats were used. The control group (group 1), silver sulfadiazine (1%) group 2, chlorhexidine acetate (0.5%) group 3, citric acid (3%) group 4, and silver-coated dressing group 5 were compared to assess the antibacterial effects of a daily application to a 30% ...

  18. Determinação simultânea dos ácidos orgânicos tartárico, málico, ascórbico e cítrico em polpas de acerola, açaí e caju e avaliação da estabilidade em sucos de caju Simulataneous determination of tartaric, malic, ascorbic and citric acids in acerola, açai and cashew pulps, and stability evaluation in cashew juices

    OpenAIRE

    Rodrigo Scherer; Ana Cecília Poloni Rybka; Helena Teixeira Godoy

    2008-01-01

    The aim of the present study was determining the main organic acids in pulp and juices, as well as evaluating their stability, after opening the package, by liquid chromatography in a C18 column with isocratic elution and UV detection. In açaí pulp tartaric, malic and citric acids were found. Cashew samples presented all of the organic acids evaluated, besides high concentrations of ascorbic and malic acids. Acerola pulp had the highest ascorbic acid concentration. A small decrease in organic...

  19. Cd、Pb复合污染下柠檬酸对龙葵修复效率及抗氧化酶的影响%Effect of citric acid on remediation efficiency and antioxidant enzyme of Solanum nigrum L.under Cd and Pb combined pollution

    Institute of Scientific and Technical Information of China (English)

    刘萍; 翟崇治; 余家燕; 鲍雷; 刘伟

    2012-01-01

    植物修复土壤重金属被普遍认为是清洁、经济的生物修复方法。为了提高生物修复土壤重金属污染的效率,在室内盆栽实验中添加柠檬酸作为螯合剂促进龙葵对重金属的吸收,并研究其生理活性的变化。结果表明:当添加柠檬酸浓度为10 nmol/kg时,龙葵生物量显著提高(P〈0.05),各部分生物量表现为:茎〉叶〉根;随着柠檬酸浓度的增加,龙葵对重金属Cd的吸收量显著(P〈0.05)增加,在10 nmol时总吸收量最大,为229.85μg/g DW;龙葵对Cd、Pb的富集系数均在柠檬酸浓度为5 nmol/kg时达到最大;Pb吸收量随柠檬酸浓度增加表现出先增大后减小的趋势;添加柠檬酸促进了龙葵对Cd的吸收,增强了抗氧化酶活性,而对Pb的吸收效果不明显。%Phytoremediation of soil heavy metals is generally considered as a clean and economical method of bioremediation.In order to improve the efficiency of bioremediation,citric acid as a chelating agent was used to enhance the uptake efficiency of Solanum nigrum L.and to study the changes of its physiological activity in the indoor pot experiment.The results showed that when citric acid’s concentration was 10 nmol/kg,the biomass of Solanum nigrum L.was significantly enhanced(P〈0.05),whose orders were as follows: stem〉leaf〉root.With the increase of the concentration of citric acid,Solanum nigrum L.had remarkably increasing absorption ability for Cd(P〈0.05),and the maximum amount of Cd could reach up to 229.85 μg/g DW when citric acid’s concentration was 10 nmol/kg.It is implied that the enrichment factors of Pb and Cd could reach up to their maximum when citric acid’s concentration was 5 nmol/kg.The amount of Pb absorbed increased at the beginning and then gradually declined while critic acid’s concentration was added.It indicated that application of citric acid significantly enhanced the absorption activity for Cd and improved the activity of

  20. Qualidade de kiwis minimamente processados e submetidos a tratamento com ácido ascórbico, ácido cítrico e cloreto de cálcio Quality of kiwis minimally processed and treated with ascorbic acid, citric acid and calcium chloride

    Directory of Open Access Journals (Sweden)

    Ana Vânia Carvalho

    2002-05-01

    Full Text Available Frutos e hortaliças minimamente processados devem apresentar atributos de conveniência e qualidade do produto fresco. O objetivo deste trabalho foi estudar o efeito do processamento mínimo de frutos tratados com soluções a 1% de ácido ascórbico, ácido cítrico e cloreto de cálcio, durante armazenamento refrigerado, na qualidade do kiwi (Actinidia deliciosa cv. Hayward. A perda de massa foi mínima durante o período de armazenamento. O ácido ascórbico fornecido pelo tratamento foi eficientemente absorvido pelos tecidos, mantendo os níveis de vitamina C cerca de 25% mais elevados nesses frutos do que nos demais tratamentos. A análise microbiológica detectou presença de bolores e leveduras e psicrotróficos, somente no tratamento com ácido cítrico, aos 8 e 10 dias, respectivamente. Não se detectaram coliformes totais e fecais e mesófilos, o que indica que o processamento foi realizado em boas condições higiênicas. Os kiwis minimamente processados e tratados com cloreto de cálcio apresentaram uma vida útil de dez dias. Nos demais tratamentos e no controle, esse tempo foi de seis dias.Minimally processed fruits and vegetables might present the same convenience and quality of fresh products. In this work, the influence of minimal processing of fruits treated with 1% solutions of ascorbic acid, citric acid and calcium chloride on the quality of kiwi (Actinidia deliciosa cv. Hayward, during refrigerated storage were investigated. Mass loss was minimal over the storage period. Ascorbic acid furnished by the treatment was effectively absorbed by tissues, keeping the vitamin C levels 25% higher in those fruits, than in other treatments. Microbiological analysis detected the presence of the group molds and yeasts and psychrotrophic in citric acid treatment, at 8 and 10 days, respectively. Total and faecal coliforms and mesophyles were not found, indicating that processing was performed under good hygienic conditions. Minimally

  1. Effect of Citric Acid on Relative Activity and Kinetic and Browning Parameters of Polyphenol Oxidase%柠檬酸对多酚氧化酶相对酶活性、动力学和褐变参数的影响

    Institute of Scientific and Technical Information of China (English)

    邹立强; 刘伟; 刘军平; 刘成梅

    2012-01-01

    以蘑菇多酚氧化酶(PPO)为原料,研究不同浓度的柠檬酸处理对PPO相对酶活性、动力学参数(米氏常数K~最大反应速率Vmax)、褐变测量参数的影响。结果表明:随着柠檬酸浓度的增加,PPO的相对酶活性逐渐降低,当柠檬酸浓度达到70mmol/L时,PPO的相对酶活性仅为原酶活性的1%;随着底物邻苯二酚浓度的增加,柠檬酸处理的PPO反应速率逐渐提高,当邻苯二酚浓度为15mmol/L时,反应速率达到最大值。随着柠檬酸浓度的增大,PPO的Vmax基本不变,而Vmax逐渐降低,经Lineweaver.Burk作图得出0、20、40mmol/L柠檬酸处理PPO的Vmax分别为578.4、437.8、111.6U/min。表明柠檬酸是PPO与底物邻苯二酚反应的非竞争抑制剂。对褐变测量参数影响表明,随着处理的柠檬酸浓度的增大,L+(亮度)、a*(红值)变化较小,而西。(黄值)急剧下降,40、70mmol/L柠檬酸处理后扫。分别降为原酶活性的57.5%和13.7%;Hue、Chroma、褐变指数(BI)也明显降低;这与PPO的相对酶活性和Vmax变化一致,表明相对酶活性、Vmax与b*、Hue、Chroma、BI有直接的相关性。%The effect of different concentrations of citric acid treatment on the relative activity, kinetic parameters (gm and Vmax) and browning parameters (Hue, Chroma and BI) of polyphenol oxidase (PPO) from mushroom. The results showed that the relative activity of PPO decreased gradually with increasing citric acid concentration and was only 1% of its original activity at 70 mmol/L. In the presence of citric acid, the reaction rate of PPO showed a gradual increase with increasing concentration of catechol, the substrate and reached its maximum level at a substrate concentration of 15 mmol/L. However, the Km remained basically unchanged despite an increase in citric acid concentration, while the Vmax gradually decreased. Lineweaver-Burk plots

  2. Combustion synthesis by reaction and characterization of nano ferrites: study of fuel aniline, citric and its mixture

    International Nuclear Information System (INIS)

    The present study aims to evaluate the influence of aniline and citric acid used alone and combined in a ratio of 50% each in the characterization of NiZn ferrite synthesized by combustion reaction method in a muffle furnace. Measurements were made of temperature and reaction time. The nano-powders were characterized by XRD, EDX, textural analysis and SEM. The highest temperature was achieved by the reaction using the mixture of fuel and increased reaction time using citric acid. The nano ferrites using different fuels, and the mixture changed phases, the crystallite size and decreased surface area of the samples with aniline, citric acid and a mixture of both, respectively. The powder morphology ranged from presenting the formation of irregular blocks for the use of citric agglomerated in the form of skeins with aniline and a mixture to agglomerate larger particles. (author)

  3. Inversão da sacarose utilizando ácido cítrico e suco de limão para preparo de dieta energética de Apis mellifera Linnaeus, 1758 Inversion of the sucrose using citric acid and lemon juice for preparing energetic diet of Apis mellifera Linnaeus, 1758

    Directory of Open Access Journals (Sweden)

    Deodoro Magno Brighenti

    2011-04-01

    nectar shortage, food supplementation using "inverted sugar" obtained by sucrose hydrolysis in an acid environment by heating can be supplied to the hive, forming a glucose and fructose mixture. The acid usually used in such a reaction is the citric acid, however, due to the difficulty that small producers have to obtain the product commercially, an alternative would be to replace it with lemon juice. The objective of this work was to quantify the inversion of sucrose present in Apis mellifera worker diets by employing commercial citric acid and lemon juice. A total of 21 aqueous solutions of granulated sugar at the proportion of 100 g/100 mL were prepared, placing in each one 1.0; 2.0; 3.0; 5.0; 10.0; 15.0 or 20.0 mL of the juices of the Galego [Citrus aurantifolia (C. Swingle], Tahiti [Citrus latifolia Tanaka] or Cravo [Citrus limonia (L. Osbeck] lemon varieties. In addition to those, six other aqueous sucrose solutions were prepared by adding 0.0 (control; 0.16; 0.3; 0.5 and 0.7 g citric acid. Sucrose inversion was quantified by using the Somogyi-Nelson method. For the Cravo lemon, the lowest inversion rate was found. Regarding the addition of citric acid, it was estimated that in placing 0.1 g, the inversion was of 12.2% while with 0.16 g, an inversion of 18.8% sucrose present in the solution. The maximum amount of citric acid to be added was estimated to be 0.18 g, adopting as a criterion the mean pH of 3.3 in Africanized bee honey. If Galego, Tahiti and Cravo lemon juices are used as replacements for the citric acid, the maximum added amount should be 2.1, 3.6 and 5.3 mL, respectively, for each 100 g sugar/100 mL water, at fixed pH of 3.3. Considering the inversion rate and pH level recommended for the use of citric acid, Tahiti lemon juice provides better results.

  4. EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA); Scientific Opinion on the substantiation of health claims related to sodium and potassium salts of citric acid and maintenance of normal bone (ID 330) pursuant to Article 13(1) of Regulation (EC) No 1924/2006

    DEFF Research Database (Denmark)

    Tetens, Inge

    Following a request from the European Commission, the Panel on Dietetic Products, Nutrition and Allergies was asked to provide a scientific opinion on a list of health claims pursuant to Article 13 of Regulation (EC) No 1924/2006. This opinion addresses the scientific substantiation of health...... claims in relation to sodium and potassium salts of citric acid and maintenance of normal bone. The scientific substantiation is based on the information provided by the Member States in the consolidated list of Article 13 health claims and references that EFSA has received from Member States or directly...... weighing the evidence, the Panel took into account that the results from the two human intervention studies provided which investigated the effects of potassium citrate on bone mineral density in post-menopausal women are conflicting, and that the adequately powered intervention study of longer duration...

  5. Citric Acid Alternative to Nitric Acid Passivation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Corrosion is an extensive problem that impacts National Aeronautics and Space Administration (NASA) and Department of Defense (DoD).  The deleterious...

  6. Water stress on citric fruit (Citrus spp.): a review

    OpenAIRE

    Javier E. Vélez; Javier G. Álvarez-Herrera; Oscar H Alvarado-Sanabria

    2012-01-01

    Citric fruit represent the main fruit product worldwide due to their advantages and benefits Adequate and homogenous moisture in the soil ensures consistent fruit quality and production, even in subtropical countries having patterns Most citric-growing areas have drip irrigation infrastructure, thereby increasing water-use efficiency However, pressure on water resources means that water use in adverse conditions must continue to be studied to ensure efficient irrigation scheduling This pap...

  7. Effects of Citric Acid on Starch-Based Barrier Coatings

    OpenAIRE

    Olsson, Erik

    2013-01-01

    With growing environmental concerns, efforts are made to replace petroleum based products with renewable alternatives. This is particularly evident in the packaging industry, where replacing synthetic polymers with renewable materials is of considerable interest. Materials for food packaging need to give protection, acting as a barrier against substances that can adversely affect the food quality such as water and oxygen. In this work, barrier dispersion coatings based on starch were used to ...

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

    Science.gov (United States)

    ... p.m. on the night before your colonoscopy. After you take this dose, you will need to drink ... about 5 hours before your colonoscopy is scheduled. After you take the second dose, you will need to ...

  9. Effects of Zn/citric acid mole fraction on the structure and luminescence properties of the un-doped and 1.5% Pb{sup 2+} doped ZnAl{sub 2}O{sub 4} powders synthesized by citrate sol–gel method

    Energy Technology Data Exchange (ETDEWEB)

    Motloung, S.V., E-mail: motloungsv@qwa.ufs.ac.za [Department of Physics, University of the Free State (Qwaqwa Campus), Private Bag X13, Phuthaditjhaba 9866 (South Africa); Dejene, F.B. [Department of Physics, University of the Free State (Qwaqwa Campus), Private Bag X13, Phuthaditjhaba 9866 (South Africa); Swart, H.C.; Ntwaeaborwa, O.M. [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein 9300 (South Africa)

    2015-07-15

    Un-doped and 1.5% Pb{sup 2+}doped zinc aluminate (ZnAl{sub 2}O{sub 4}) was successfully prepared at a relatively low temperature (~80 °C) using the sol–gel process. The Zn/citric acid (CA) mole fraction was varied from 0.083 to 1.3. The X-ray diffraction (XRD) data revealed that most of the annealed samples consist of the cubic ZnAl{sub 2}O{sub 4} structure with ZnO impurities. The surface morphology of the phosphors was influenced by the Zn/CA mole fractions. The increase in the CA content lead to the morphological evolution and transformation from small particles to rods-like-needles. The nanopowder samples exhibited violet luminescence that varied from 400 to 410 nm, which suggested that the CA content affected the bandgap energy of the host. The results suggest that the emission originated either from the host, Pb{sup 2+} or ZnO impurities. Emission at 400 nm is attributed to the oxygen vacancies (V{sub 0}{sup *}) in the host and emission peak at 410 nm is attributed to the intrinsic defects emission of ZnO, while the emission at 552 nm is attributed to the second order emission of the excitation wavelength. The emission intensity was influenced by the Zn/CA mole fractions. The CIE colour coordinates of all samples are close to each other in the blue region. Two distinct peaks were observed at around 160 and 385 °C in thermo luminescence (TL) glow curve, which indicates that there are two set of traps. - Highlights: • Un-doped and 1.5% Pb{sup 2+}doped zinc aluminate (ZnAl{sub 2}O{sub 4}) was successfully prepared at a relatively low temperature (~80 °C) using the sol–gel process. • The increase in the catalyst content lead to the morphological evolution from small particles to rods-like-needles. • The catalyst content affected the band gap energy of the host. • Results showed that the emission can only arise from the host and ZnO impurities. • CIE colour coordinates of all samples is situated in the blue region of the chart.

  10. Synthesis of Citric-Acrylate Oligomer and its in-Situ Reaction with Chrome Tanned Collagen (hide powder)

    International Nuclear Information System (INIS)

    The purpose of this study was to formulate the new combined system of acrylic and citric acids, which has been prepared by free radical polymerization and esterification reaction at the same time to form citric acrylate (CAC) oligomer through ester linkage and low molecular weight (Mw 2241), in compared with polyacrylic acid. The chemical structure and the reaction mechanism of this oligomer were confirmed by different spectroscopic tools (1H, 13C-NMR, ATR-IR), gel permeation chromatography and thermogravimetric analysis (TGA/DTA). The problem of the effect of the masking agents in the chrome tanning of the collagen and the pickling of the hide has been approached from the study of the hydrothermal and mechanical properties, using this new eco-friendly oligomer, which was carried out in-situ treated/grafted chrome tanned collagen (hide powder), and pickled hide. The microemulsion grafting copolymerization of (CAC) using 2.2-azo-bis isobutyronitrile (ABIN), via direct coupling reaction, onto the chrome tanned collagen showed that the free amino groups of the collagen were considered to be a potential site for the in-situ reaction with (CAC) oligomer. Also, using of citric-acrylate (CAC) oligomer, during chrome tanning of leather, instead of the traditional strong acids (sulfuric, hydrochloric and formic) resulted in significant improvement in chrome exhaustion and physical properties

  11. Citric waste saccharification under different chemical treatments

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo de Farias Silva

    2015-10-01

    Full Text Available Second generation ethanol from lignocellulose materials has been used in applications for food processing wastes. Since Brazil has a leading position in orange juice exports, the influence of acid and alkali pretreatments on liquor saccharification, solubilization of solid fraction and mass yield was evaluated. Time and Cacid or Calkaline at different concentrations of solids (low to moderate, 1 to 9% and high catalyst concentrations were analyzed. A hydrothermal pretreatment was conducted under the same conditions of acid and alkaline treatments to investigate the relative selectivity increase in using the catalysts. The chemical analyses of wastes indicated a 70% total carbohydrate level denoting a promising raw material for bioethanol production. Pretreatment caused acid saccharifications between 25 and 65% in total reducing sugars (TRS and mass yields (MY between 30 and 40%. In alkaline pretreatment, these rates ranged between 2 and 22.5% and between 30 and 80, respectively. In hydrothermal pretreatment, solubilized TRS varied between 3 and 37%, whereas MY remained between 45 and 60%, respectively. Cbiomass strongly influenced the three variables; in the same way, time affected MY.

  12. Citric Gel Synthesis and Luminescent Properties of Ce3+-Activated SrGa2O4 Phosphor

    Institute of Scientific and Technical Information of China (English)

    Qiao Bin; Tang Zilong; Zhang Zhongtai; Chen Lei

    2007-01-01

    Ce3+-activated SrGa2O4 phosphor was synthesized by a method of citric gel, wherein citric acid served as a chelate agent, and the as-synthesized powder was calcined in a slightly reduced ambient. The crystallization characteristics of the sample varied with the calcining temperature. Compared with the phosphor prepared by the solid-state reaction, the phosphor synthesized by citric gel was calcined at a relatively lower temperature. Consequently, the volatilization of Ga2O3 during high-temperature calcining process was avoided. The typical double-peak emission of Ce3+ originated from 2D(5d)→4F5/2(4f), and 2D(5d)→4F7/2(4f) was observed, and the intrinsic emission of SrGa2O4 host was much restricted. The emission intensity varied with the calcining temperature because the different crystallinity and the optimal concentration of Ce-dopant was determined at 3%.

  13. Uranium recovery from a citric-citrate leach liquor of rock phosphate using an ion-exchange resin

    International Nuclear Information System (INIS)

    Previous work has indicated that uranium could be selectively leached from rock phosphates by a proper mixture of citric acid-calcium citrate. Uranium was recovered from the obtained leach liquor via methylation after its evaporation. However, in order to minimize the cost of uranium recovery by such a process, an anion exchange resin (Amberlite IRA-400) is suggested to be applied for uranium recovery from the liquors in concern. The achieved saturation capacity of 220 gu/l W SR represented only about 60% of the theoretical capacity of the resin (371 gu/i). This relatively low resin capacity might be due to excessively high citric-citric concentration or due to sluggish working flow rate, . Comparing the theoretical resin capacity of 371 gu/l W SR for a monovalent uranyl citrate complexes to that of only 92.8 in case of the tetravalent tri sulphate tri carbonate uranyl complexes, it would be greatly beneficial to apply the citrate for uranium adsorption upon anion exchange resins.3 figs

  14. Adição de ácido cítrico potencializa a ação de ácidos húmicos e altera o perfil protéico da membrana plasmática em raízes de milho Citric acid addition improve humic acids action and change proteins profile from plasma membrane of maize roots

    Directory of Open Access Journals (Sweden)

    Janaína Aparecida Hottz Rima

    2011-04-01

    ízes.The plant growth stimulation by humic acids (HA has been attributed to a hormone-like effect as promoting the root development and proliferation, resulting in a more efficient water and nutrient absorption. This research aims to investigate how the humic acids isolated from vermicompost (20mg L-1 can modify the root architecture and the plasma membrane (PM protein patterns in maize roots. It was also analyzed the effect of the citric acid (CA, an organic acid present in root exudates. The changes induced in the corn root system were estimated by measuring the taproot length, the amount of root mitotic sites and lateral roots, and the total root area. Plasma membrane vesicles were purified by cell fractionation and the protein patterns were analyzed by uni (1D and bidimensional (2D electrophoresis. The results show that the HA in solution with CA (0.005mM increases the lateral root growth promotion (126%, the root area (58%, and the number of lateral roots (55%. The activity of the plasma membrane H+ pump, analyzed as a marker of the induction of the acid growth mechanism, was also enhanced (374% by the humic solution supplemented with CA. Expression of several plasma membrane proteins was inhibited when plants were treated with HA and this effect was more pronounced upon CA supplementation. The obtained results corroborate the proposed mechanism for the HA bioactivity, by which under the action of root-exuded organic acids, such as CA, a disruption of the HA macrostructure is promoted releasing bioactive molecules presented in the humic aggregates, which becomes more accessible to the root cell receptors.

  15. Relative efficacy of organic acids and antibiotics as growth promoters in broiler chicken

    Directory of Open Access Journals (Sweden)

    Vikrant Laxman Bagal

    2016-04-01

    Full Text Available Aim: The objective of this study was to evaluate the effect of organic acids as replacer to antibiotics in their various combinations on feed consumption, body weight gain, and feed conversion ratio (FCR in broiler chicks during different phases of growth. Materials and Methods: Antibiotics and organic acids were incorporated into boiler feed in different combinations to form 10 maize based test diets (T1 to T10. Each test diet was offered to four replicates of 10 birds each constituting a total of 400 birds kept for 45 days. Results: Significantly better effect in terms of body weight gain from supplementation of 1% citric acid and 1% citric acid along with antibiotic was observed throughout the entire study, whereas the effect of tartaric acid supplementation was similar to control group. Citric acid (1% along with antibiotic supplementation showed highest feed intake during the experimental period. Significantly better FCR was observed in groups supplemented with 1% citric acid and 1% citric acid along with antibiotic followed by antibiotic along with organic acids supplemented group. Conclusion: Growth performance of birds in terms of body weight, body weight gain, and FCR improved significantly in 1% citric acid which was significantly higher than antibiotic supplemented group. 1% citric acid can effectively replace antibiotic growth promoter (chlortetracycline without affecting growth performance of birds.

  16. Flotation separation of rare earth ions with the acid of citric acid and hexadecylamine

    International Nuclear Information System (INIS)

    The possibilities of the flotation method of rare earth ion separation by their transfer in citrate complexes and their following binding into slightly soluble well-floated compounds-sublates with the aid of hexadecylamine are studied. The dependences of the degree of neodymium, samarium and europium flotation separation on hexadecylamine consumption, on solution pH and temperature are presented. Free energies of sublate formation cntaining neodymium, samarium and europium are presented. The research has shown the possibility of flotation separation of rare earth ions by the above method

  17. Citric pectin. Effect of steam haulage in the extraction and of different drying methods

    International Nuclear Information System (INIS)

    It is carried out this investigation with the purpose of determining the effects of steam haulage and of two drying methods in extracted pectin of orange shell, using the residuals of the machine processor of the Caldas region, that it uses the system In Line in the obtaining of the juice for the effect. The essential oils were eliminated the pericarp with haulage of steam, the pectin was extracted with solution to 50% of citric acid and hexametaphosphate of sodium to 0.2%. For shell weight the extraction temperature was of 80 applied during one hour and the pH of 3.4. The pectin was characterized extracted by means of determinations of humidity, ashy, nitrogen, methoxyl percentage, anhidrogalacturonic acid, pH, and acidity. Their behavior is also evaluated by means of determinations that are carried out to the gel with them prepared as its hardness, time and low temperature. They use a totally aleatory statistical design in factorial arrangement 3x2, three treatments: T1 flavedo and albedo with haulage of steam, T2 albedo with steam haulage and T3 albedo without steam haulage and two drying methods, with hot air and with microwaves. The results were analyzed by means of ANDEVA and tests of comparison of Tuckey and Scheff at a level of probability of 95%. They concluded that the steam haulage doesn't have significant influence in the characteristics of the obtained product while, the drying for microwaves influenced significantly in a positive way in the characteristics of the extracted pectin

  18. Disproportionation of the calcium salt of atorvastatin in the presence of acidic excipients

    DEFF Research Database (Denmark)

    Christensen, Niels Peter Aae; Rantanen, Jukka; Cornett, Claus;

    2012-01-01

    . Of the excipients investigated, citric acid and polyacrylic acid were found to induce disproportionation. Moreover, it was also observed that exposure to high relative humidity, elevated temperatures, and milling all promoted disproportionation. The results suggest that disproportionation of drug...

  19. The effect of oxalic and itaconic acids on threo-Ds-isocitric acid production from rapeseed oil by Yarrowia lipolytica.

    Science.gov (United States)

    Kamzolova, Svetlana V; Allayarov, Ramil K; Lunina, Julia N; Morgunov, Igor G

    2016-04-01

    The effect of oxalic and itaconic acids, the inhibitors of the isocitrate lyase, on the production of isocitric acid by the wild strain Yarrowia lipolytica VKM Y-2373 grown in the medium containing rapeseed oil was studied. In the presence of oxalic and itaconic acids, strain Y. lipolytica accumulated in the medium isocitric acid (70.0 and 82.7g/L, respectively) and citric acid (23.0 and 18.4g/L, respectively). In control experiment, when the inhibitors were not added to the medium, the strain accumulated isocitric and citric acids at concentrations of 62.0 and 28.0g/L, respectively. Thus, the use of the oxalic and itaconic acids as additives to the medium is a simple and convenient method of isocitric acid production with a minimum content of citric acid. PMID:26851896

  20. Organic acids, sugars, vitamin C content and some pomological characteristics of eleven hawthorn species (Crataegus spp.) from Turkey

    OpenAIRE

    Muttalip Gundogdu; Koray Ozrenk; Sezai Ercisli; Tuncay Kan; Ossama Kodad; Attila Hegedus

    2014-01-01

    BACKGROUND: The Hawthorn (Crateagus sp.) mostly occurs around the temperate region of the world with a high number of species, producing a fruit with numerous beneficial effects for human health. The aim of the study was to determine organic acid and sugar contents in the fruit of a number of hawthorn species grown in Erzincan province of Turkey. RESULTS: Citric acid was the predominant organic acid in all hawthorn species and C. pseudoheterophylla had the highest citric acid content (23.688 ...

  1. Sorption of small quantities of silver on silicic acid under the conditions of complex formation

    International Nuclear Information System (INIS)

    Present article is devoted to sorption of small quantities of silver on silicic acid under the conditions of complex formation. Study of precipitation of small quantities of silver (4.2·10-5mg/l) from the solutions of oxalic, tartaric and citric acids depending on ph showed that under these conditions the precipitation does not occur. This is due to formation of stable and soluble in the water silver complex compounds with oxalic, tartaric and citric acids.

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

    Science.gov (United States)

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

  3. 21 CFR 184.1007 - Aconitic acid.

    Science.gov (United States)

    2010-04-01

    ... salt from cane sugar or molasses. It may be synthesized by sulfuric acid dehydration of citric acid...) and 1 CFR part 51, and a molecular weight of 174.11. Copies of the material incorporated by reference...-103, which is incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51....

  4. [Effect of Low Molecular Weight Organic Acids on the Chemical Speciation and Activity of Mercury in the Soils of the Water-Level-Fluctuating Zone of the Three Gorges Reservoir].

    Science.gov (United States)

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

    2016-01-15

    To investigate the effect of low molecular weight organic acids ( LMWOA) on the ability of migration and the species of mercury in the soil of the Water-Level-Fluctuating Zone of the Three Gorges Reservoir, citric acid, tartaric acid and oxalic acid were dded into the soil to conduct simulation experiments. The results showed that the percentage of exchangeable mercury increased with the increase of the concentration of citric acid, but the value declined slightly as the concentration of tartaric acid and oxalic acid increased. While all three acids elevated the bioavailability of mercury, which increased with the increase of the concentration of acids. Vhen the concentration of citric acid reached 15 mmol x L(-1), the activation effect was the best. But for oxalic acid and citric acid, 10 mmol x L(-1) was the optimal concentration. In general, the effect of three organic acids on the activation of mercury in the soil followed the trend of citric acid > tartaric acid > oxalic acid. In the soil supplemented with 15 mmol x L(-1) citric acid, the change of mercury pecies was more and more striking with the prolonged incubation, and the conversion did not stop until 14 d, at that time the stomach cid dissolved mercury increased obviously, which was mainly converted from elemental mercury. PMID:27078955

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

    OpenAIRE

    Weerayuth SUTTIRAK; Supranee MANURAKCHINAKORN

    2010-01-01

    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. Th...

  6. Analysis of organic acids in Macedonian wines by capillary electrophoresis

    OpenAIRE

    Jancovska, Maja; Ivanova, Violeta; Gulaboski, Rubin; Belder, Detlev

    2013-01-01

    Capillary electrophoresis as a separation technique can be applied for analysis of organic acids in white and red wines, providing high resolution separation of the analytes. Organic acids such as of tartaric, malic, lactic citric and succinic acids have been analysed in many Macedonian red and white wines by capillary electrophoresis, and results have been discussed.

  7. Analysis of Organic Acids in Blueberry Juice and its Fermented Wine by High Performance Liquid Chromatography

    Directory of Open Access Journals (Sweden)

    Hongxue Fu

    2015-08-01

    Full Text Available A rapid analytical method for simultaneous separation and determination of organic acids is of the essence for quality control of blueberry juice and its fermented wine. In this present study, a High Performance Liquid Chromatography (HPLC method for separation and determination of organic acids (oxalic acid, gluconic acid, tartaric acid, formic acid, pyruvic acid, malic acid, isocitric acid, shikimic acid, lactic acid, acetic acid, citric acid, succinic acid and propionic acid in blueberry juice and wine has been developed. The chromatographic separation was performed at 35°C by using an ammonium hydrogen phosphate buffer (pH 2.8 as mobile phase and 0.6 mL/min as the column flow rate. A C18 analytical column and Ultraviolet Detection (UV at &lembda = 210 nm were used for all acids above. The method was validated for linearity, limit of detection, limit of quantification, accuracy and precision. The applicability of the method was demonstrated by analyzing organic acids in real samples of six species of blueberry juices and wines. The results show that species significantly affect distribution of organic acids in samples but not the kinds of organic acids between six species. Oxalic acid, gluconic acid, malic acid, shikimic acid and citric acid are detected in blueberry juice. Citric acid, which accounts for a percentage >75% of the whole content of organic acids, is the major acid in four kinds of tested species (Sharpblue, Misty, Anna and Bluecrop. In the other two species (Britewell and Premier, malic acid, gluconic acid and citric acid own a mean percentage of 40, 32 and 25%, respectively. After yeast fermentation and aging, several new organic acids (pyruvic acid, isocitric acid, lactic acid, acetic acid, succinic acid and propionic acid appear in wine.

  8. Effect of Low-Molecular-Weight Organic Acids on Cl- Adsorption by Variable Charge Soils

    Institute of Scientific and Technical Information of China (English)

    XU Ren-Kou; ANG Ma-Li; WANG Qiang-Sheng; JI Guo-Liang1

    2004-01-01

    Low-molecular-weight (LMW) organic acids exist widely in soils and have been implicated in many soil processes.The objective of the present paper was to evaluate effect of two LMW organic acids, citric acid and oxalic acid, on Cl- adsorption by three variable charge soils, a latosol, a lateritic red soil and a red soil, using a batch method. The results showed that the presence of citric acid and oxalic acid led to a decrease in Cl- adsorption with larger decreases for citric acid. Among the different soils Gl- adsorption in the lateritic red soil and the red soil was more affected by both the LMW organic acids than that in the latosol.

  9. 78 FR 34648 - Citric Acid and Certain Citrate Salts: Preliminary Results of Countervailing Duty Administrative...

    Science.gov (United States)

    2013-06-10

    ... Countervailing Duty Order, 74 FR 25705 (May 29, 2009), remains dispositive. A full description of the scope of... countervailing duties at the most recent company- specific or all-others rate applicable to the company. These... 6. Benchmark and Discount Rates 7. Analysis of Programs 8. Conclusion BILLING CODE 3510-DS-P...

  10. Slow release anti-fungal skin formulations based on citric acid intercalated layered double hydroxides nanohybrids

    OpenAIRE

    Perera, Jayoda; Weerasekera, Manjula; Kottegoda, Nilwala

    2015-01-01

    Background During the past few decades, the occurrence of superficial fungal infections has rapidly increased. As the fungal infections take longer time to get cured, concepts such as designing drugs with extended persistence and controlled release have gained attention. In this context, nanotechnology has been identified as the latest technological revolution which has opened up new pathways for designing new therapeutic materials. Out of the many available nano-structures layered double hyd...

  11. Alternative reactions at the interface of glycolysis and citric acid cycle in Saccharomyces cerevisiae.

    Science.gov (United States)

    van Rossum, Harmen M; Kozak, Barbara U; Niemeijer, Matthijs S; Duine, Hendrik J; Luttik, Marijke A H; Boer, Viktor M; Kötter, Peter; Daran, Jean-Marc G; van Maris, Antonius J A; Pronk, Jack T

    2016-05-01

    Pyruvate and acetyl-coenzyme A, located at the interface between glycolysis and TCA cycle, are important intermediates in yeast metabolism and key precursors for industrially relevant products. Rational engineering of their supply requires knowledge of compensatory reactions that replace predominant pathways when these are inactivated. This study investigates effects of individual and combined mutations that inactivate the mitochondrial pyruvate-dehydrogenase (PDH) complex, extramitochondrial citrate synthase (Cit2) and mitochondrial CoA-transferase (Ach1) in Saccharomyces cerevisiae. Additionally, strains with a constitutively expressed carnitine shuttle were constructed and analyzed. A predominant role of the PDH complex in linking glycolysis and TCA cycle in glucose-grown batch cultures could be functionally replaced by the combined activity of the cytosolic PDH bypass and Cit2. Strongly impaired growth and a high incidence of respiratory deficiency in pda1Δ ach1Δ strains showed that synthesis of intramitochondrial acetyl-CoA as a metabolic precursor requires activity of either the PDH complex or Ach1. Constitutive overexpression of AGP2, HNM1, YAT2, YAT1, CRC1 and CAT2 enabled the carnitine shuttle to efficiently link glycolysis and TCA cycle in l-carnitine-supplemented, glucose-grown batch cultures. Strains in which all known reactions at the glycolysis-TCA cycle interface were inactivated still grew slowly on glucose, indicating additional flexibility at this key metabolic junction. PMID:26895788

  12. Formation Equilibria of Ternary Metal Complexes with Citric Acid and Glutamine (Alanine) in Aqueous Solution

    Institute of Scientific and Technical Information of China (English)

    王进平; 牛春吉; 杨魁跃; 倪嘉缵

    2004-01-01

    The species and their formation constants in the ternary systems were obtained by the Scogs2 software from potentiometric titration data. The Comics software was used to calculate the distribution of species in the ternary systems. MLXH, MLXH2 and MLXH3 are the common species in these systems. The coordination behaviors of the rare earths are very similar and their stability is closely matched. The ternary rare earth complexes are more stable than the corresponding ternary complexes of calcium. The ternary zinc complex with glutamine as the secondary ligand is more stable than the corresponding complexes of rare earths, but the ternary complex with alanine as the secondary ligand shows an inverse trend. The distributions of species in the ternary systems vary with pH changing. A prediction can be made that exogenous rare earths can affect the species of Ca and Zn in human body.

  13. 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

    FD4 across Caco-2 monolayers and rat small intestinal mucosae mounted in Ussing chambers. Proteolytic degradation of insulin was determined in rat luminal extracts across a range of pH values in the presence of CA. CA's capacity to chelate calcium decreased ~10-fold for each pH unit moving from pH 6...

  14. Production of citric acid from glycerol by Yarrowia lipolytica – optimization of culture conditions

    OpenAIRE

    M. Mota; Ferreira, Patrícia; Belo, Isabel

    2013-01-01

    The global expansion of biodiesel production turned the glycerol (the main byproduct of this industry) into an excess product, consequently available at low cost on the market. Despite the well-known applications of pure glycerol, it is important to look for new ways to valorize the raw glycerol; it can be through biotechnological alternatives, by its use to produce high added value compounds. Several microorganisms are able to use glycerol and convert it into different compounds....

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

    OpenAIRE

    Shabnam Mohammadi; Parisa Ziarati

    2015-01-01

    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 remo...

  16. Influence of sodium fluoride and malonate on the respiration and metabolism of di- and tricarboxylic acids in chicory leaves

    Energy Technology Data Exchange (ETDEWEB)

    Mazurova, T.A.; Tenchurina, N.S.

    1975-01-01

    Fluoride has a weak inhibitory effect on leaf respiration and the production of pyruvic acid. During 24 h the accumulation of citric and malic acids without effect on the tartaric acid was demonstrated. The inhibitory effect of fluoride was increased by pyruvate. The pyruvic acid stimulates both CO/sub 2/-output and O/sub 2/-consumption. The accumulation of citric and malic acids is influenced by pyruvic acid, but the tartaric acid content decreases. The malonate has a strong inhibitory effect on leaf respiration and induces the accumulation of succinic acid, the strong decrease of citric and malic acids but the decrease of the content of tartaric acid. The inhibitory effect of malonate was eliminated by succinate. Glucolysis is probably not the main pathway in the production of pyruvate in the chicory leaves.

  17. Reductive Acid Leaching of Low Grade Manganese Ores

    OpenAIRE

    Alok Prasad Das; Sarpras Swain; Shriyanka Panda; Nilotpala Pradhan; Lala Behari Sukla

    2012-01-01

    Manganese recoveries from low-grade ores using organic acids as reducing agents were investigated in the present work. The acid leaching potential of both oxalic acid and citric acid were estimated. Manganese leaching amount were measured by using standard manganese curve and estimated by titration method. Effects of various acid concentrations on leaching efficiency were studied. The observed result suggested prominent manganese recovery of 66% by oxalic acid at 2 M concentration whereas cit...

  18. Determination of organic acids evolution during apple cider fermentation using an improved HPLC analysis method

    NARCIS (Netherlands)

    Zhang, H.; Zhou, F.; Ji, B.; Nout, M.J.R.; Fang, Q.; Zhang, Z.

    2008-01-01

    An efficient method for analyzing ten organic acids in food, namely citric, pyruvic, malic, lactic, succinic, formic, acetic, adipic, propionic and butyric acids, using HPLC was developed. Boric acid was added into the mobile phase to separate lactic and succinic acids, and a post-column buffer solu

  19. A Thermostable Salmonella Phage Endolysin, Lys68, with Broad Bactericidal Properties against Gram-Negative Pathogens in Presence of Weak Acids

    DEFF Research Database (Denmark)

    Oliveira, Hugo; Thiagarajan, Viruthachalam; Walmagh, Maarten;

    2014-01-01

    circular dichroism analysis demonstrated the ability to refold into its original conformation upon thermal denaturation. It was shown that Lys68 is able to lyse a wide panel of Gram-negative bacteria (13 different species) in combination with the outer membrane permeabilizers EDTA, citric and malic acid....... While the EDTA/Lys68 combination only inactivated Pseudomonas strains, the use of citric or malic acid broadened Lys68 antibacterial effect to other Gram-negative pathogens (lytic activity against 9 and 11 species, respectively). Particularly against Salmonella Typhimurium LT2, the combinatory effect of...... malic or citric acid with Lys68 led to approximately 3 to 5 log reductions in bacterial load/CFUs after 2 hours, respectively, and was also able to reduce stationary-phase cells and bacterial biofilms by approximately 1 log. The broad killing capacity of malic/citric acid-Lys68 is explained by the...

  20. ORGANIC ACIDS CONCENTRATION IN WINE STOCKS AFTER SACCHAROMYCES CEREVIISIIAE FERMENTATION

    OpenAIRE

    Bayraktar, V.

    2013-01-01

    The biochemical constituents in wine stocks that influence the flavor and quality of wine are investigated in the paper. The tested parameters consist of volume fraction of ethanol, residual sugar, phenolic compounds, tartaric, malic, citric, lactic, acetic acids, titratable acidity and volatile acids. The wine stocks that were received from white and red grape varieties Tairov`s selection were tested. There was a correlation between titratable acidity and volatile acids in the wine stocks fr...

  1. A deficiency of manganese ions in the presence of high sugar concentrations is the critical parameter for achieving high yields of itaconic acid by Aspergillus terreus.

    Science.gov (United States)

    Karaffa, Levente; Díaz, Rafael; Papp, Benedek; Fekete, Erzsébet; Sándor, Erzsébet; Kubicek, Christian P

    2015-10-01

    Itaconic acid (IA), an unsaturated dicarboxylic acid with a high potential as a platform for chemicals derived from sugars, is industrially produced by large-scale submerged fermentation by Aspergillus terreus. Although the biochemical pathway and the physiology leading to IA is almost the same as that leading to citric acid production in Aspergillus niger, published data for the volumetric (g L(-1)) and the specific yield (mol/mol carbon source) of IA are significantly lower than for citric acid. Citric acid is known to accumulate to high levels only when a number of nutritional parameters are carefully adjusted, of which the concentration of the carbon source and that of manganese ions in the medium are particularly important. We have therefore investigated whether a variation in these two parameters may enhance IA production and yield by A. terreus. We show that manganese ion concentrations obtain highest yields. Highest yields were also dependent on the concentration of the carbon source (D-glucose), and highest yields (0.9) were only obtained at concentrations of 12-20 % (w/v), thus allowing the accumulation of up to 130 g L(-1) IA. These findings perfectly mirror those obtained when these parameters are varied in citric acid production by A. niger, thus showing that the physiology of both processes is widely identical. Consequently, applying the fermentation technology established for citric acid production by A. niger citric acid production to A. terreus should lead to high yields of IA, too. PMID:26078111

  2. Effect of a natural organic acid-icing system on the microbiological quality of commercially relevant chilled fish species

    OpenAIRE

    Sanjuás, Minia; García-Soto, Bibiana; Fuertes-Gamundi, José R.; Aubourg, Santiago P.; Barros-Velázquez, J.

    2012-01-01

    Natural preservative organic acids (ascorbic, citric and lactic acids) were used to prepare a novel organic acid-flake icing system for the chilled preservation of hake (Merluccius merluccius), megrim (Lepidorhombus whiffiagonis) and angler (Lophius piscatorius). The icing system was prepared with two different concentrations of a commercial acid mixture-formula containing the three organic acids at 800 mg/kg and 400 mg/kg (C-800 and C-400 batches, respectively). Aerobic mesophiles, psychrotr...

  3. Polyol and Amino Acid-Based Biosurfactants, Builders, and Hydrogels

    Science.gov (United States)

    This chapter reviews different detergent materials which have been synthesized from natural agricultural commodities. Background information, which gives reasons why the use of biobased materials may be advantageous, is presented. Detergent builders from L-aspartic acid, citric acid and D-sorbitol...

  4. Interesting Starter Culture Strains for Controlled Cocoa Bean Fermentation Revealed by Simulated Cocoa Pulp Fermentations of Cocoa-Specific Lactic Acid Bacteria ▿

    OpenAIRE

    Lefeber, Timothy; Janssens, Maarten; Moens, Frédéric; Gobert, William; De Vuyst, Luc

    2011-01-01

    Among various lactic acid bacterial strains tested, cocoa-specific strains of Lactobacillus fermentum were best adapted to the cocoa pulp ecosystem. They fermented glucose to lactic acid and acetic acid, reduced fructose to mannitol, and converted citric acid into lactic acid and 2,3-butanediol.

  5. [Relationships between cadmium accumulation and organic acids in leaves of Solanum nigrum L. as a cadmium-hyperaccumulator].

    Science.gov (United States)

    Sun, Rui-lian; Zhou, Qi-xing; Wang, Xin

    2006-04-01

    The influence of different cadmium concentrations on the organic acid level in leaves of the Cd hyperaccumulator, Solanum nigrum L., in particular, the relationship of organic acids with Cd accumulation in S. nigrum was investigated based on the pot-culture experiment. The results showed that the Cd concentration in S. nigrum leaves exceeded 100 microg x g(-1), the threshold value used to define Cd-hyperaccumulators, and the bioaccumulation coefficient of cadmium in shoots of S. nigrum was higher than 1 when Cd concentration in soil was 25 microg x g(-1). The level of organic acids in leaves of S. nigrum had significant differences between the seedling stage and the mature stage. At the seedling stage, the sequence of organic acids in leaves of S. nigrum was acetic acid> tartaric acid> malic acid> citric acid. On the contrary, the accumulation of organic acids in S. nigrum at the mature stage was approximately in the following sequence malic acid> tartaric acid, acetic acid> citric acid. The significant positive correlation between Cd accumulation in leaves of S. nigrum and the concentration of tartaric acid in leaves of S. nigrum was observed at the seedling stage, whereas there was a significant positive correlation between Cd accumulation in leaves of S. nigrum and both acetic and citric acid concentrations at the mature stage. These results indicated that tartaric, acetic and citric acids in leaves of S. nigrum might act as the indication of Cd hyperaccumulation. PMID:16768003

  6. Mechanisms of Radionuclide-Hyroxycarboxylic Acid Interactions for Decontamination of Metallic Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    A.J. Francis; C.J. Dodge; J.B. Gillow; G.P. Halada; C.R. Clayton

    2002-04-24

    Is this EMSP program we investigated the key fundamental issues involved in the use of simple and safe methods for the removal of radioactive contamination from equipment and facilities using hydroxycarboxylic acids. Specifically, we investigate (i) the association of uranium with various iron oxides commonly formed on corroding plain carbon steel surfaces, (ii) the association of uranium with corroding metal coupons under a variety of conditions, and (iii) the decontamination of the uranium contaminated metal coupons by citric acid or citric acid formulations containing oxalic acid and hydrogen peroxide.

  7. Mechanisms of Radionuclide-Hyroxycarboxylic Acid Interactions for Decontamination of Metallic Surfaces; FINAL

    International Nuclear Information System (INIS)

    Is this EMSP program we investigated the key fundamental issues involved in the use of simple and safe methods for the removal of radioactive contamination from equipment and facilities using hydroxycarboxylic acids. Specifically, we investigate (i) the association of uranium with various iron oxides commonly formed on corroding plain carbon steel surfaces, (ii) the association of uranium with corroding metal coupons under a variety of conditions, and (iii) the decontamination of the uranium contaminated metal coupons by citric acid or citric acid formulations containing oxalic acid and hydrogen peroxide

  8. 27 CFR 24.182 - Use of acid to correct natural deficiencies.

    Science.gov (United States)

    2010-04-01

    ... citric acid may be added to citrus fruit, juice or wine, only malic acid may be added to apples, apple... (including berries) may be added within the limitations of § 24.246 to juice or wine in order to correct natural deficiencies; however, no acid may be added to juice or wine which is ameliorated to...

  9. Determination of organic acid components from fruits of Chaenomeles speciosa by GC-MS%皱皮木瓜果实中有机酸成分的GC-MS分析

    Institute of Scientific and Technical Information of China (English)

    龚复俊; 陈玲; 卢笑丛; 王有为

    2005-01-01

    The constituents and contents of esterifing derivatives of organic and aqueous phases in extracts from Chaenomeles speciosa (Sweet) Nakai fruits were analysed by GC-MS. The results indicated that there were 15 and 17 compounds in organic and aqueous phases, respectively. Besides there were common fatty acids, there were a lof of binary acids and ternary acids. The contents of malic acid and citric acid in aqueous and organic phases reached to 64.007%, 70.492% and 30.305%, 22.121% respectively. Therefore, malic acid and citric acid are the major constituents of organic acids in C. speciosa fruits.

  10. Organic acids composition of Cydonia oblonga Miller leaf

    OpenAIRE

    Andreia P. Oliveira; Pereira, J.A.; Andrade, P.B.; Valentão, P.; Seabra, R.M.; B.M. Silva

    2008-01-01

    Organic acid profiles of 36 Cydonia oblonga Miller leaf samples, from three different geographical origins of northern (Bragança and Carrazeda de Ansiães) and central Portugal (Covilhã), harvested in three collection months (June, August and October of 2006), were determined by HPLC/UV (214 nm). Quince leaves presented a common organic acid profile, composed of six constituents: oxalic, citric, malic, quinic, shikimic and fumaric acids. C. oblonga leaves total organic acid content varied from...

  11. Effects of Lactic Acid Bacteria Inoculated Fermentation on Pickled Cucumbers

    OpenAIRE

    Xiaoyi Ji; Yuan Wu; Xingzhu Wu; Yonghua Lin; Weiwei Xu; Hui Ruan; Guoqing He

    2013-01-01

    The aim of this study was to determine the effects of Lactic Acid Bacteria (LAB) fermentation on the texture and organic acid of pickled cucumbers. Texture and sensory evaluation as well as a microscopic observation were performed to study the textural differences among fresh cucumber, Spontaneous fermentation (SF) cucumber and LAB Inoculating Fermentation (LABIF) cucumber. Accumulation of seven organic acids i.e., oxalic, tartaric, malic, lactic, acetic, citric and succinic acid during cucum...

  12. Effect of Organic Acids Supplement on Performance of Broiler Chickens

    Directory of Open Access Journals (Sweden)

    Ján Kopecký

    2012-05-01

    Full Text Available This study was conducted in order to evaluate effect of organic acids on broiler performance. Totally 180 chickens of Ross 308 hybrid were divided to three groups. Experimental group no. 1 (n=60 received acetic acid in drinking water with concentration 0.25% from day 1 to day 42. Experimental group no. 2 (n=60 received citric acid in drinking water with concentration 0.25% from day 1 to day 42. Control group (n=60 received drinking water without any additives. The average body weight, feed consumption, mortality and carcass characteristics were analyzed and compared finally. The results showed no significant effects of diets with addition of organic acids (P<0.05 on body weight. Supplementation of citric acid caused decrease in total feed consumption. Addition of organic acids affected positive total mortality of broiler chickens. There were no significant effects of organic acids supplementation on carcass characteristics.

  13. Influence of the use of acids and films in post-harvest lychee conservation

    Directory of Open Access Journals (Sweden)

    Danielle Fabíola Pereira da Silva

    2012-12-01

    Full Text Available Lychee (Litchi chinensis Sonn. has a high commercial value; however, it has a short shelf-life because of its rapid pericarp browning. The objective of this study was to evaluate the shelf-life of 'Bengal' lychee fruits stored after treatment with hydrochloric acid and citric acid, associated with cassava starch and plastic packaging. Uniformly red pericarp fruits were submitted to treatments: 1-(immersion in citric acid 100 mM for 5 minutes + cassava starch 30 g L-1 for 5 minutes, 2-(immersion in hydrochloric acid 1 M for 2 minutes + starch cassava 30 g L-1 for 5 minutes, 3-(immersion in citric acid 100 mM for 5 minutes + polyvinyl chloride film (PVC, 14 µm thick and 4-(immersion in hydrochloric acid 1 M for 2 minutes + PVC film. During 20 days, the fruits were evaluated for mass loss, pericarp color, pH, soluble solids and titratable acidity, vitamin C of the pulp and pericarp and activities of polyphenol oxidase and peroxidase of the pericarp. The treatment with hydrochloric acid associated with PVC was the most effective in maintaining the red color of the pericarp for a period of 20 days and best preservation of the fruit. The cassava starch associated with citric acid, and hydrochloric acid did not reduce the mass loss and did not prevent the browning of lychee fruit pericarp.

  14. Dissolution kinetics of nickel laterite ore using different secondary metabolic acids

    Directory of Open Access Journals (Sweden)

    S. Sahu

    2011-06-01

    Full Text Available The dissolution kinetics of nickel laterite ore in aqueous acid solutions of three metabolic acids, i.e., citric acid, oxalic acid and acetic acid were investigated in a batch reactor individually. It was determined that experimental data comply with a shrinking core model. The diffusion coefficients for citric acid, oxalic acid and acetic acid were found to be 1.99×10-9 cm²/s, 2.59×10-8 cm²/s and 1.92×10-10 cm²/s respectively. The leaching ability of each acid was observed and it was found that oxalic acid was better than the other two.

  15. The Extraction of Gelatine from Mackerel (Scomber scombrus) Heads with the use of Different Organic Acids

    OpenAIRE

    Khiari, Zied; Rico, Daniel; Martin-Diana, Ana Belen; Barry-Ryan, Catherine

    2011-01-01

    Fish processing by-products are considered a potential resource for bioactive and functional compounds. In this study, gelatines from mackerel (Scomber scombrus) heads were extracted using five different organic acids (acetic, citric, lactic, malic and tartaric acids). The organic acid slightly affected the extraction yield but there was no significant (p>0.05) differences were observed. The amino acid profiling found that 3 glycine, proline and hydroxyproline were the major amino acids prese...

  16. HPLC Organic Acid Analysis in Different Citrus Juices under Reversed Phase Conditions

    OpenAIRE

    Violeta NOUR; Ion TRANDAFIR; Mira Elena IONICA

    2010-01-01

    A reversed phase HPLC method for separation and quantification of organic acids (oxalic, citric, tartaric, malic, ascorbic and lactic acids) in fruit juices was developed. The chromatographic separation was performed with a Surveyor Thermo Electron system at 10C by using potassium dihydrogen orthophosphate buffer (pH 2.8) as mobile phase, an Hypersil Gold aQ Analytical Column and diode array detection at ?=254 nm for ascorbic acid and ?=214 nm for the other organic acids. Organic acid ...

  17. Effects of Spray Drying on Physicochemical Properties of Chitosan Acid Salts

    OpenAIRE

    Cervera, Mirna Fernández; Heinämäki, Jyrki; de la Paz, Nilia; López, Orestes; Maunu, Sirkka Liisa; Virtanen, Tommi; Hatanpää, Timo; Antikainen, Osmo; Nogueira, Antonio; Fundora, Jorge; Yliruusi, Jouko

    2011-01-01

    The effects of spray-drying process and acidic solvent system on physicochemical properties of chitosan salts were investigated. Chitosan used in spray dryings was obtained by deacetylation of chitin from lobster (Panulirus argus) origin. The chitosan acid salts were prepared in a laboratory-scale spray drier, and organic acetic acid, lactic acid, and citric acid were used as solvents in the process. The physicochemical properties of chitosan salts were investigated by means of solid-state CP...

  18. Oxidative stability of structured lipids produced from sunflower oil and caprylic acid

    DEFF Research Database (Denmark)

    Timm Heinrich, Maike; Xu, Xuebing; Nielsen, Nina Skall;

    2003-01-01

    commercial antioxidant blend Grindox 117 (propyl gallate/citric acid/ascorbyl palmitate) or gallic acid to the SL was investigated. The lipid type affected the oxidative stability: SL was less stable than SO and RL. The reduced stability was most likely caused by both the structure of the lipid and...

  19. Analysis of Organic Acids, Deacetyl Asperulosidic Acid and Polyphenolic Compounds as a Potential Tool for Characterization of Noni (Morinda citrifolia) Products.

    Science.gov (United States)

    Bittová, Miroslava; Hladůkova, Dita; Roblová, Vendula; Krácmar, Stanislav; Kubán, Petr; Kubán, Vlastimil

    2015-11-01

    Organic acids, deacetyl asperulosidic acid (DAA) and polyphenolic compounds in various noni (Morinda citrifolia L.) products (4 juices, 4 dry fruit powders and 2 capsules with dry fruit powder) were analyzed. Reversed-phase high-performance liquid chromatography (RP-HPLC) coupled with a variable wavelength detector (VWD) and electrospray ionization time-of-flight mass spectrometer (ESI-TOF MS) was applied for simultaneous analysis of organic acids (malic, lactic, citric and succinic acid) and DAA. An RP-HPLC method with diode-array detector (DAD) was developed for the analysis of polyphenolic compound content (rutin, catechin, quercitrin, kaempferol, gallic acid, caffeic acid and p-coumaric acid). The developed methods can contribute to better characterization of available noni products that is required from the consumers. In our study, we discovered significant dissimilarities in the content of DAA, citric acid and several phenolic compounds in some samples. PMID:26749805

  20. Estimation of the radiological impact in the use of phosphate fertilizer in citric plantations

    International Nuclear Information System (INIS)

    The use of fertilizers in the agriculture is a potential danger of environmental contamination, because the elements contained in them could suffer an important redistribution in the environment. This is the case of radioactive elements of natural origin, like K-40 and nuclides of U and Th series, present in the ores used in the production of industrial fertilizers. Phosphoric rocks used in fertilizers contain, generally, important concentrations of radioactive elements greater than other rocks of the earth core. In Cuba, preliminary determinations of Ra-226 concentrations in phosphoric rocks reveal results in the order of 2.7 Bq/kg. These values are greater than the mean of the rest of soils of the country. Due to this fact, a study on the radiological impact of this practice was developed. The study was carried out in citric plantations of the province of Pinar del Rio, where phosphate fertilizer is widely used. Samples of different parts of the plant were taken and analyzed by means of gamma spectrometric techniques. The paper presents values for Ra-226 that are in the range 27-40 Bq/kg. These results show that the use of fertilizers does not imply a significant radiological impact. Punctual valves of transfer coefficients of Ra-226 in soil -stem-leave-peel and - juice chains were estimated. (authors). 6 refs., 4 tabs

  1. Development and evaluation of acid-buffering bioadhesive vaginal tablet for mixed vaginal infections

    OpenAIRE

    Alam, Mohd Aftab; Ahmad, Farhan Jalees; KHAN, ZEENAT IQBAL; Khar, Roop Krishen; ALI, MUSHIR

    2007-01-01

    An acid-buffering bioadhesive vaginal tablet was developed for the treatment of genitourinary tract infections. From the bioadhesion experiment and release studies it was found that polycarbophil and sodium carboxymethylcellulose is a good combination for an acid-buffering bioadhesive vaginal tablet. Sodium monocitrate was used as a buffering agent to provide acidic pH (4.4), which is an attribute of a healthy vagina. The effervescent mixture (citric acid and sodium bicarbonate) along with a ...

  2. Antimicrobial and cytotoxic effects of phosphoric acid solution compared to other root canal irrigants

    OpenAIRE

    PRADO, Maíra; Emmanuel João Nogueira Leal da SILVA; Thais Mageste DUQUE; ZAIA, Alexandre Augusto; Ferraz, Caio Cezar Randi; de Almeida, José Flávio Affonso; GOMES, Brenda Paula Figueiredo de Almeida

    2015-01-01

    Phosphoric acid has been suggested as an irrigant due to its effectiveness in removing the smear layer. Objectives : The purpose of this study was to compare the antimicrobial and cytotoxic effects of a 37% phosphoric acid solution to other irrigants commonly used in endodontics. Material and Methods : The substances 37% phosphoric acid, 17% EDTA, 10% citric acid, 2% chlorhexidine (solution and gel), and 5.25% NaOCl were evaluated. The antimicrobial activity was tested against Candida albican...

  3. Preparation of High-purity Indium Oxalate Salt from Indium Scrap by Organic Acids

    Energy Technology Data Exchange (ETDEWEB)

    Koo, Su-Jin; Ju, Chang-Sik [Pukyoung National University, Busan (Korea, Republic of)

    2013-12-15

    Effect of organic acid on the preparation of indium-oxalate salt from indium scraps generated from ITO glass manufacturing process was studied. Effects of parameters, such as type and concentration of organic acids, pH of reactant, temperature, reaction time on indium-oxalate salt preparation were examined. The impurity removal efficiency was similar for both oxalic acid and citric acid, but citric acid did not make organic acid salt with indium. The optimum conditions were 1.5 M oxalic acid, pH 7, 80 .deg. C, and 6 hours. On the other hand, the recoveries increased with pH, but the purity decreased. The indium-oxalate salt purity prepared by two cycles was 99.995% (4N5). The indium-oxalate salt could be converted to indium oxide and indium metal by substitution reaction and calcination.

  4. Influence of organic acids on the transport of heavy metals in soil.

    Science.gov (United States)

    Schwab, A P; Zhu, D S; Banks, M K

    2008-06-01

    Vegetation historically has been an important part of reclamation of sites contaminated with metals, whether the objective was to stabilize the metals or remove them through phytoremediation. Understanding the impact of organic acids typically found in the rhizosphere would contribute to our knowledge of the impact of plants in contaminated environments. Heavy metal transport in soils in the presence of simple organic acids was assessed in two laboratory studies. In the first study, thin layer chromatography (TLC) was used to investigate Zn, Cd, and Pb movement in a sandy loam soil as affected by soluble organic acids in the rhizosphere. Many of these organic acids enhanced heavy metal movement. For organic acid concentrations of 10mM, citric acid had the highest R(f) values (frontal distance moved by metal divided by frontal distance moved by the solution) for Zn, followed by malic, tartaric, fumaric, and glutaric acids. Citric acid also has the highest R(f) value for Cd movement followed by fumaric acid. Citric acid and tartaric acid enhanced Pb transport to the greatest degree. For most organic acids studied, R(f) values followed the trend Zn>Cd>Pb. Citric acid (10mM) increased R(f) values of Zn and Cd by approximately three times relative to water. In the second study, small soil columns were used to test the impact of simple organic acids on Zn, Cd, and Pb leaching in soils. Citric acid greatly enhanced Zn and Cd movement in soils but had little influence on Pb movement. The Zn and Cd in the effluents from columns treated with 10mM citric acid attained influent metal concentrations by the end of the experiment, but effluent metal concentrations were much less than influent concentrations for citrate <10mM. Exchangeable Zn in the soil columns was about 40% of total Zn, and approximately 80% total Cd was in exchangeable form. Nearly all of the Pb retained by the soil columns was exchangeable. PMID:18482743

  5. Hanford waste vitrification plant hydrogen generation study: Preliminary evaluation of alternatives to formic acid

    International Nuclear Information System (INIS)

    Oxalic, glyoxylic, glycolic, malonic, pyruvic, lactic, levulinic, and citric acids as well as glycine have been evaluated as possible substitutes for formic acid in the preparation of feed for the Hanford waste vitrification plant using a non-radioactive feed stimulant UGA-12M1 containing substantial amounts of aluminum and iron oxides as well as nitrate and nitrite at 90C in the presence of hydrated rhodium trichloride. Unlike formic acid none of these carboxylic acids liberate hydrogen under these conditions and only malonic and citric acids form ammonia. Glyoxylic, glycolic, malonic, pyruvic, lactic, levulinic, and citric acids all appear to have significant reducing properties under the reaction conditions of interest as indicated by the observation of appreciable amounts of N2O as a reduction product of,nitrite or, less likely, nitrate at 90C. Glyoxylic, pyruvic, and malonic acids all appear to be unstable towards decarboxylation at 90C in the presence of Al(OH)3. Among the carboxylic acids investigated in this study the α-hydroxycarboxylic acids glycolic and lactic acids appear to be the most interesting potential substitutes for formic acid in the feed preparation for the vitrification plant because of their failure to produce hydrogen or ammonia or to undergo decarboxylation under the reaction conditions although they exhibit some reducing properties in feed stimulant experiments

  6. Biobased organic acids production by metabolically engineered microorganisms

    DEFF Research Database (Denmark)

    Chen, Yun; Nielsen, Jens

    2016-01-01

    expanded as organic acids constitute a key group among top building block chemicals that can be produced from renewable resources. Here we review the current status for production of citric acid and lactic acid, and we highlight the use of modern metabolic engineering technologies to develop high......Bio-based production of organic acids via microbial fermentation has been traditionally used in food industry. With the recent desire to develop more sustainable bioprocesses for production of fuels, chemicals and materials, the market for microbial production of organic acids has been further...

  7. 76 FR 34048 - Citric Acid and Certain Citrate Salts From the People's Republic of China: Preliminary Results of...

    Science.gov (United States)

    2011-06-10

    ... barge freight reported in a March 19, ] 2007 article published in The Hindu Business Line. The data is... Republic of China: Antidumping Duty Orders, 74 FR 25703 (May 29, 2009). \\2\\ See Initiation of Antidumping and Countervailing Duty Administrative Reviews and Requests for Revocation in Part, 75 FR 37759...

  8. 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

    ... Request Administrative Review, 75 FR 23236-37 (May 3, 2010). On June 1, 2010, in accordance with 19 CFR... Countervailing Duty Administrative Reviews and Requests for Revocation in Part, 75 FR 37759 (June 30, 2010). On... Group Co., Ltd. Shanghai Henglijie Bio-Tech Co., Ltd. Shanghai Fenhe Biochemical Co., Ltd. Shanxi...

  9. Synthesis and characterization of polymers based on citric acid and glycerol: Its application in non-biodegradable polymers

    Directory of Open Access Journals (Sweden)

    Jaime Alfredo Mariano-Torres

    2015-01-01

    Full Text Available El notable incremento mundial en el consumo de plásticos y su l argo tiempo de residencia en el ambiente muestran la gran neces idad de productos con caracterís ticas biodegradables. En este proyecto fueron desarrollados polímeros biodegradables a base del ácido cítrico y del glicerol. La síntesis de esto s se lleva a cabo a diferentes condiciones de concentración y a temperatura constante. Se des arrollaron mediante un proceso económicamente viable. Se caracterizaron p or medio de las siguientes técnicas: Numero ácido, espectroscop ia infrarroja FTIR, índice de refracc ión, viscosidad, análisis de impacto, ensayo de tensión, dure za, calorimetría, el % de Humed ad (método de la estufa con recirculación de aire, determinación de densi dad, además de pruebas cualitativas para corroborar su biodegra dabilidad. Los polímeros elaborados fueron mezclados con una formulación de PVC grado médico, obteniendo un polímero hibrido y se pudo observar que modifica sus propiedades mecánicas.

  10. 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

    ... Countervailing Duty Proceedings: Electronic Filing Procedures; Administrative Protective Order Procedures, 76 FR... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE..., International Trade Administration, Department of Commerce. SUMMARY: The Department of Commerce...

  11. Carbonate and citric acid leaching of uranium from uranium-contaminated soils: Pilot-scale studies (Phase II)

    International Nuclear Information System (INIS)

    The purpose of this document is to describe the results of the soil decontamination demonstration conducted at the Fernald Environmental Management Project (FEMP) site by the Fernald Environmental Restoration and Management Corporation (FERMCO) and the Oak Ridge National Laboratory (ORNL). This demonstration, which began in November 1993 and ended in October 1994, involved the removal of uranium from contaminated soil sampled from two FEMP sites. The demonstration was conducted so as to meet the requirements of the Fernald Site Integrated Demonstration program, as well as all environmental, safety, and health requirements of the site

  12. Point mutation of the xylose reductase (XR) gene reduces xylitol accumulation and increases citric acid production in Aspergillus carbonarius

    OpenAIRE

    Weyda, István; Lübeck, Mette; Ahring, Birgitte K; Peter S. Lübeck

    2014-01-01

    Aspergillus carbonarius accumulates xylitol when it grows on d-xylose. In fungi, d-xylose is reduced to xylitol by the NAD(P)H-dependent xylose reductase (XR). Xylitol is then further oxidized by the NAD+-dependent xylitol dehydrogenase (XDH). The cofactor impairment between the XR and XDH can lead to the accumulation of xylitol under oxygen-limiting conditions. Most of the XRs are NADPH dependent and contain a conserved Ile-Pro-Lys-Ser motif. The only known naturally occurring NADH-dependent...

  13. 77 FR 33167 - Citric Acid and Certain Citrate Salts From the People's Republic of China: Preliminary Results of...

    Science.gov (United States)

    2012-06-05

    ... Determination of Sales at Less than Fair Value: Static Random Access Memory Semiconductors from Taiwan, 63 FR... government's involvement in the market. See Preamble to Countervailing Duty Regulations, 63 FR 65348, 65377... the Department reach its determination on the role of the CCP with regard to the government and...

  14. Composition of quince (Cydonia oblonga Miller) seeds: phenolics, organic acids and free amino acids.

    Science.gov (United States)

    Silva, Branca M; Andrade, Paula B; Ferreres, Federico; Seabra, Rosa M; Oliveira, M Beatriz P P; Ferreira, Margarida A

    2005-04-01

    Phenolic compounds, organic acids and free amino acids of quince seeds were determined by HPLC/DAD, HPLC/UV and GC/FID, respectively. Quince seeds presented a phenolic profile composed of 3-O-caffeoylquinic, 4-O-caffeoylquinic, 5-O-caffeoylquinic and 3,5-dicaffeoylquinic acids, lucenin-2, vicenin-2, stellarin-2, isoschaftoside, schaftoside, 6-C-pentosyl-8-C-glucosyl chrysoeriol and 6-C-glucosyl-8-C-pentosyl chrysoeriol. Six identified organic acids constituted the organic acid profile of quince seeds: citric, ascorbic, malic, quinic, shikimic and fumaric acids. The free amino acid profile was composed of 21 identified free amino acids and the three most abundant were glutamic and aspartic acids and asparagine. PMID:15702641

  15. Different low-molecular-mass organic acids specifically control leaching of arsenic and lead from contaminated soil

    Science.gov (United States)

    Ash, Christopher; Tejnecký, Václav; Borůvka, Luboš; Drábek, Ondřej

    2016-04-01

    Low-molecular-mass organic acids (LMMOA) are of key importance for mobilisation and fate of metals in soil, by functioning as ligands that increase the amount of dissolved metal in solution or by dissociation of metal binding minerals. Column leaching experiments were performed on soil polluted with As and Pb, in order to determine the specificity of LMMOA related release for individual elements, at varying organic acid concentrations. Acetic, citric and oxalic acids were applied in 12 h leaching experiments over a concentration range (0.5-25 mM) to soil samples that represent organic and mineral horizons. The leaching of As followed the order: oxalic > citric > acetic acid in both soils. Arsenic leaching was attributed primarily to ligand-enhanced dissolution of mineral oxides followed by As released into solution, as shown by significant correlation between oxalic and citric acids and content of Al and Fe in leaching solutions. Results suggest that subsurface mineral soil layers are more vulnerable to As toxicity. Leaching of Pb from both soils followed the order: citric > oxalic > acetic acid. Mineral soil samples were shown to be more susceptible to leaching of Pb than samples characterised by a high content of organic matter. The leaching efficiency of citric acid was attributed to formation of stable complexes with Pb ions, which other acids are not capable of. Results obtained in the study are evidence that the extent of As and Pb leaching in contaminated surface and subsurface soil depends significantly on the types of carboxylic acid involved. The implications of the type of acid and the specific element that can be mobilised become increasingly significant where LMMOA concentrations are highest, such as in rhizosphere soil.

  16. Alternative to Nitric Acid for Passivation of Stainless Steel Alloys

    Science.gov (United States)

    Lewis, Pattie L.; Kolody, Mark; Curran, Jerry

    2013-01-01

    Corrosion is an extensive problem that affects the Department of Defense (DoD) and National Aeronautics and Space Administration (NASA). The deleterious effects of corrosion result in steep costs, asset downtime affecting mission readiness, and safety risks to personnel. Consequently, it is vital to reduce corrosion costs and risks in a sustainable manner. The DoD and NASA have numerous structures and equipment that are fabricated from stainless steel. The standard practice for protection of stainless steel is a process called passivation. Typical passivation procedures call for the use of nitric acid; however, there are a number of environmental, worker safety, and operational issues associated with its use. Citric acid offers a variety of benefits including increased safety for personnel, reduced environmental impact, and reduced operational cost. DoD and NASA agreed to collaborate to validate citric acid as an acceptable passivating agent for stainless steel. This paper details our investigation of prior work developing the citric acid passivation process, development of the test plan, optimization of the process for specific stainless steel alloys, ongoing and planned testing to elucidate the process' resistance to corrosion in comparison to nitric acid, and preliminary results.

  17. Complex Formation of Selected Radionuclides with Ligands Commonly Found in Ground Water: Low Molecular Organic Acids

    DEFF Research Database (Denmark)

    Jensen, Bror Skytte; Jensen, H.

    1985-01-01

    A general approach to the analysis of potentiometric data on complex formation between cations and polybasic amphoteric acids is described. The method is used for the characterisation of complex formation between Cs+, Sr2+, Co2+, La 3+, and Eu3+ with a α-hydroxy acids, tartaric acid and citric acid......, and with the α-amino acids, aspartic acid and L-cysteine. The cations have been chosen as typical components of reactor waste, and the acids because they are often found as products of microbial activity in pits or wherever organic material decays...

  18. Modeling the adsorption of weak organic acids on goethite: the ligand and charge distribution model

    OpenAIRE

    Filius, J.D.

    2001-01-01

    A detailed study is presented in which the CD-MUSIC modeling approach is used in a new modeling approach that can describe the binding of large organic molecules by metal (hydr)oxides taking the full speciation of the adsorbed molecule into account. Batch equilibration experiments were performed using the iron (hydr)oxide goethite to determine the adsorption of a series of weak organic acids (e.g. lactic acid, oxalic acid, malonic acid, phthalic acid, citric acid, and fulvic acid). In order t...

  19. Effect of curd freezing and packaging methods on the organic acid contents of goat cheeses during storage

    Directory of Open Access Journals (Sweden)

    Pınar Balkir

    2011-09-01

    Full Text Available Effects of freezing and packaging methods on organic acid content of goat cheese during 12 weeks of storage were determined. Goat cheese milk curds were divided into two batches; one of the batches was directly processed in to goat cheese while the other was frozen at -18 °C and stored for six months and processed into cheese after being thawed. Cheese samples were packed in three parts and stored at 4 °C refrigerated control sample and at -18 °C for six months frozen experimental samples. Cheese samples were packed in three different packaging methods: aerobic, vacuum or modified atmosphere. Citric, malic, fumaric, acetic, lactic, pyruvic and propionic acids were analyzed using HPLC method after 1st, 3rd, 6th, 9th and 12th week of storage period. Lactic acid was the main organic acids while pyruvic acid had the lowest content in all cheese samples. Citric and fumaric acid levels of frozen samples increased during storage whereas malic, acetic, pyruvic and propionic acid amounts were decreased compared to the beginning of storage. Packaging methods and freezing process also effected lactic acid levels statistically (p<0.05. Fumaric, acetic and lactic acid concentration of refrigerated samples were increased but citric, malic and propionic acids decreased during storage. Pyruvic acid level did not change significantly. It was determined that organic acid concentrations were effected by freezing process, storage time and packaging methods significantly (p<0.05.

  20. Separation and determination of some carboxylic acids by capillary electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Sladkov, V.; Fourest, B

    2006-07-01

    Separation and determination of some organic acids, mono-carboxylic (formic and acetic), dicarboxylic (oxalic and tartaric), tricarboxylic (citric) acids and aromatic acids (phtalic, benzoic, mellitic and trimellitic), by capillary electrophoresis are reviewed. The method development parameters, such as separation and injection mode, are discussed. Special attention is paid to the comparison of different detection types (spectroscopic and electrochemical). The optimisation of the carrier electrolyte composition (choice of carrier electrolyte, effect of pH, ionic strength, electro-osmotic flow modifier) is treated. Different additives (alkali-earth and transition metal ions, cyclodextrins and alcohol), which are often used for improving organic acid separation, are also considered. (authors)

  1. Separation and determination of some carboxylic acids by capillary electrophoresis

    International Nuclear Information System (INIS)

    Separation and determination of some organic acids, mono-carboxylic (formic and acetic), dicarboxylic (oxalic and tartaric), tricarboxylic (citric) acids and aromatic acids (phtalic, benzoic, mellitic and trimellitic), by capillary electrophoresis are reviewed. The method development parameters, such as separation and injection mode, are discussed. Special attention is paid to the comparison of different detection types (spectroscopic and electrochemical). The optimisation of the carrier electrolyte composition (choice of carrier electrolyte, effect of pH, ionic strength, electro-osmotic flow modifier) is treated. Different additives (alkali-earth and transition metal ions, cyclodextrins and alcohol), which are often used for improving organic acid separation, are also considered. (authors)

  2. Treatment of broiler litter with organic acids.

    Science.gov (United States)

    Ivanov, I E

    2001-04-01

    Experiments for treatment of contaminated broiler litter with citric, tartaric and salicylic acids were performed. At days 2 and 6 after the treatment, pH values (using a pH-meter), the ammonia concentrations (titration with 0.1 N HCl) and the microbial cells counts were determined in both experimental and control specimens of litter. The cost of acidification of litter was also determined. Our studies showed that the treatment of the contaminated litter with 5 per cent citric acid, 4 per cent tartaric acid and 1.5 per cent salicylic acid created an acid medium with pH under 5.0 and thus reduced the microbial counts to 2.2 x 10(3)colony forming units per gram manure litter. The treatment reduced the content of ammonia in the litter and in the air under the hygienic limits, i.e. 25-50 ppm. The cost of acidification of litter with these organic acids amounted to 0.1 $ per bird and 1.5 $ per 15 birds on one square metre in a growth period of 50 days. PMID:11356097

  3. The influence of pH adjusted with different acids on the dyeability of polyester fabric

    Directory of Open Access Journals (Sweden)

    Miljkovic Milena N.

    2014-12-01

    Full Text Available The influence of using formic, oxalic, citric, tartaric, hydrochloric, nitric, sulphuric and phosphoric acid for dyebath pH adjustment was investigated upon the dyeing of polyester fabric with CI Disperse Yellow 60. The positions of colour in CIELab coordinates of the samples dyed with the addition of tested acids were assessed and compared to those dyed with the addition of acetic acid. It was found that the differences in dyeabilities obtained with the addition of citric, oxalic, hydrochloric, nitric and sulphuric acid are entirely acceptable according to both M&S 83A and CMC (2:1 standards in comparison to the dyeability obtained with the addition of acetic acid.

  4. Potentiodynamic studies on anodic dissolution and passivation of tin, indium and tin-indium alloys in some fruit acids solutions

    International Nuclear Information System (INIS)

    The anodic dissolution and passivation of tin, indium and tin-indium alloys were studied in 0.5 M solutions of both malic and citric acids, using potentiodynamic technique and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The E/I curves showed that the anodic behavior of all investigated electrodes exhibits active/passive transition. The active region of tin involves two anodic peaks (I and II) prior to the passive region in both the investigated acids, while indium exhibits two peaks (I and II) in malic and one peak in citric acid. These two peaks (I and II) correspond to the formation of InOOH and In(OH)3/In2O3 system, respectively, but that observed peak in citric acid is to InOOH. The active region for tin-indium alloys (I, II and III) in citric acid showed one peak (I) and shoulders (II). This shoulder predominates with increasing temperature due to little In2O3 formation and its dissolution at higher temperatures. The disappearance of this shoulder for the alloys (IV and V) with high indium percent may be due to the formation of large amounts of In2O3 with tin oxides on the surface.

  5. Distribution of 14C-activity among the organic acids in the Satsuma mandarin fruits fed with 14C-compounds

    International Nuclear Information System (INIS)

    1. Twenty four hours after 14CO2 feeding to the leaves, malic acid had the highest level of total and specific radioactivity among the organic acids extracted from the juice vesicles, and citric acid had the second highest total activity. An unidentified acid compound had a relatively high activity. 2. Pyruvic acid-2-14C was fed as a substrate for acid formation to the one young fruit on a shoot, and NaH14CO3 was fed as a source of carbon-dioxide to the other young fruit through the pedicel. After three hours of pyruvic acid feeding, malic acid, citric acid and aspartic acid were the major labelled compounds in the vesicles. Then, a marked increase and redistribution of activity in acids took place with time, and the levels of total and specific activity in citric acid increased steadily. The sorts of labelled compounds into which activity was incorporated from NaH14CO3 were essentially similar to those in pyruvic acid-2-14C feeding. 3. These results seem to support the theory that the dark fixation of carbon-dioxide plays an important role in the synthesis of the organic acids in citrus fruit vesicles. (auth.)

  6. Synthesis of itaconic acid from the irradiation of aconitic acid-clay suspensions

    International Nuclear Information System (INIS)

    The radiolysis of aconitic acid in aqueous solution and in water-clay suspensions was studied. Among the radiolytic products, itaconic acid (HO2C-C(=CH2)-CH2CO2H) was formed. Itaconic acid is a valuable monomer in the formulation of polymers. The synthesis of itaconic acid can be achieved in one step using aqueous solutions of aconitic acid and in water-clay suspensions exposed to ionizing radiation. The yield of formation does not compete with fermentation procedures for the synthesis of itaconic acid, but for laboratory purposes is a very simple method to prepare it. Other products of the radiolysis were carbon dioxide, tricarballylic and citric/isocitric acids. (Author)

  7. Effect of root derived organic acids on the activation of nutrients in the rhizosphere soil

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Four types of soils, including brown coniferous forest soil, dark brown soil, black soil, and black calic soil, sampled from three different places in northeast China were used in this test. The functions of two root-derived organic acids and water were simulated and compared in the activation of mineral nutrients from the rhizosphere soil. The results showed that the organic acids could activate the nutrients and the activated degree of the nutrient elements highly depended on the amount and types of the organic acid excreted and on the physiochemical and biochemical properties of the soil tested. The activation effect of the citric acid was obviously higher than that of malic acid in extracting Fe, Mn, Cu, and Zn for all the tested soil types. However, the activation efficiencies of P, K, Ca, and Mg extracting by the citric acid were not much higher, sometimes even lower, than those by malic acid. The solution concentration of all elements increased with increase of amount of the citric acid added.

  8. Surface complexation modeling of uranium (Vi) retained onto zirconium diphosphate in presence of organic acids

    International Nuclear Information System (INIS)

    In the field of nuclear waste disposal, predictions regarding radionuclide migration through the geosphere, have to take account the effects of natural organic matter. This work presents an investigation of interaction mechanisms between U (Vi) and zirconium diphosphate (ZrP2O7) in presence of organic acids (citric acid and oxalic acid). The retention reactions were previously examined using a batch equilibrium method. Previous results showed that U (Vi) retention was more efficient when citric acid or oxalic acid was present in solid surface at lower ph values. In order to determine the retention equilibria for both systems studied, a phosphorescence spectroscopy study was carried out. The experimental data were then fitted using the Constant Capacitance Model included in the FITEQL4.0 code. Previous results concerning surface characterization of ZrP2O7 (surface sites density and surface acidity constants) were used to constraint the modeling. The best fit for U (Vi)/citric acid/ZrP2O7 and U (Vi)/oxalic acid/ZrP2O7 systems considered the formation of a ternary surface complex. (Author)

  9. Effect of Organic Acids on Bacterial Cellulose Produced by Acetobacter xylinum

    Directory of Open Access Journals (Sweden)

    Hongmei Lu

    2016-03-01

    Full Text Available Based on the difference of bacterial cellulose production from rice saccharificate medium and chemical medium under static cultivation, effect of organic acids in the process of bacterial cellulose produced by A. xylinum was studied. The results showed that the kinds and contents of organic acids were different in both culture medium, in which accumulated oxalic acid and tartaric acid inhibited A. xylinum producing BC in chemical medium, while pyruvic acid, malic acid, lactic acid, acetic acid, citric acid and succinic acid, as ethanol, promoted A. xylinum to produce BC. Compared to the blank BC production 1.48 g/L, the optimum addition concentrations of pyruvic acid, malic acid, lactic acid, acetic acid, citric acid, succinic acid, and ethanol in chemical medium were 0.15%, 0.1%, 0.3%, 0.4%, 0.1%, 0.2% , 4% and the BC productions were 2.49 g/L, 2.83 g/L, 2.12 g/L, 2.54 g/L, 2.27 g/L, 1.88 g/L , 2.63 g/L, respectively. The co-existence of above organic acids and ethanol increased BC production even further.

  10. Effects of organic acid pickling on the corrosion resistance of magnesium alloy AZ31 sheet

    DEFF Research Database (Denmark)

    Nwaogu, Ugochukwu Chibuzoh; Blawert, C.; Scharnagl, N.; Dietzel, W.; Kainer, K. U.

    2010-01-01

    mu m of the contaminated surface was required to reach corrosion rates less than 1 mm/year in salt spray condition. Among the three organic acids examined, acetic acid is the best choice. Oxalic acid can be an alternative while citric acid is not suitable for cleaning AZ31 sheet, because of......Organic acids were used to clean AZ31 magnesium alloy sheet and the effect of the cleaning processes on the surface condition and corrosion performance of the alloy was investigated. Organic acid cleanings reduced the surface impurities and enhanced the corrosion resistance. Removal of at least 4...

  11. Obtaining a citric tristeza virus p65 protein antibody and preliminary results of p65 in vivo expression

    Directory of Open Access Journals (Sweden)

    Yanneth Torres

    2007-04-01

    Full Text Available The citric tristeza virus (CTV belongs to the Closteroviridae family which indudes the only vegetal viruses possessing genes homologous to HSP70 thermal cellular shock proteins in their genome. Such is the case of the gene encoding for the CTV p65 protein which presents high homology with the HSP70 protein family. It has been shown recently that HSP70h viral proteins (such as CTV p65 are involved both in viral assembly, as a microtubule binding protein, and in cell-cell movement. Since CTV is the most deleterious citrus pathogen, understanding this protein's role in the pathogenesis process is important. Rabbits were immunised with four synthetic peptides (corresponding to CTV p65 thermal shock protein's carboxyl-terminal region to obtain polyclonal antibodies. All the peptides used were immunogenic, even though two of them showed greater response. Whilst none of the antibodies obtained reacted to non-infected plant extract, the p65 proteins was detected in extracts taken from citric plants infected with CTV Based on the antibody's reaction to two Colombian isolates having different serological characteristics, the p65 antibody's immunological behaviour appeared to be independent of the symptomatic severity of the CTV isolates. It was shown that the ORF encoded for the HSP70 homologue in CTV was expressed in vivo, even though the p65 antibody was only detected in concentrated protein extracts taken from infected plants, supporting reports from other studies that the concentration of this protein in plants infected with CTV is low. This is the first time that a polyclonal CTV antibody has been obtained in Colombia against p65 (a protein intervening in viral assembly and movement. Adapting a technique for obtaining p65 antibodies by using synthetic peptides as immunogens could be useful in the future for detecting or diagnosing p65 proteins present in different Colombian CTV isolates, especially in developing studies contributing towards greater

  12. Recovery of vanadium from spent catalysts of sulfuric acid plant by using inorganic and organic acids: Laboratory and semi-pilot tests.

    Science.gov (United States)

    Erust, Ceren; Akcil, Ata; Bedelova, Zyuldyz; Anarbekov, Kuanysh; Baikonurova, Aliya; Tuncuk, Aysenur

    2016-03-01

    Catalysts are used extensively in industry to purify and upgrade various feeds and to improve process efficiency. These catalysts lose their activity with time. Spent catalysts from a sulfuric acid plant (main elemental composition: 5.71% V2O5, 1.89% Al2O3, 1.17% Fe2O3 and 61.04% SiO2; and the rest constituting several other oxides in traces/minute quantities) were used as a secondary source for vanadium recovery. Experimental studies were conducted by using three different leaching systems (citric acid with hydrogen peroxide, oxalic acid with hydrogen peroxide and sulfuric acid with hydrogen peroxide). The effects of leaching time, temperature, concentration of reagents and solid/liquid (S/L) ratio were investigated. Under optimum conditions (1:25 S/L ratio, 0.1M citric acid, 0.1M hydrogen peroxide, 50°C and 120min), 95% V was recovered in the presence of hydrogen peroxide in citric acid leaching. PMID:26711187

  13. Implication of organic acids in the long-distance transport and the accumulation of lead in Sesuvium portulacastrum and Brassica juncea.

    Science.gov (United States)

    Ghnaya, Tahar; Zaier, Hanen; Baioui, Raoudha; Sghaier, Souhir; Lucchini, Giorgio; Sacchi, Gian Attilio; Lutts, Stanley; Abdelly, Chedly

    2013-01-01

    The implication of organic acids in Pb translocation was studied in two species varying in shoot lead accumulation, Sesuvium portulacastrum and Brassica juncea. Citric, fumaric, malic and α-cetoglutaric acids were separated and determined by HPLC technique in shoots, roots and xylem saps of the both species grown in nutrient solutions added with 200 and 400 μM of Pb(II). The lead content of the xylem saps was determined by ICP-MS. Results showed that S. portulacastrum is more tolerant to Pb than B. juncea. Lead concentration in xylem sap of the S. portulacastrum was significantly greater than in that of B. juncea. For both species, a positive correlation was established between lead and citrate concentrations in xylem sap. However minor relationship was observed for fumaric, malic and α-cetoglutaric acids. In the shoots lead treatment also induced a significant increase in citric acid concentration. Both observations suggest the implication of citric acid in lead translocation and shoot accumulation in S. portulacastrum and B. juncea. The relatively high accumulation of citric acid in xylem sap and shoot of S. portulacastrum could explain its high potential to translocate and accumulate this metal in shoot suggesting their possible use to remediate Pb polluted soils. PMID:23026160

  14. Preparation of lactic acid bacteria fermented wheat-yoghurt mixtures

    Directory of Open Access Journals (Sweden)

    Michal Magala

    2013-09-01

    Full Text Available Background. Tarhana, a wheat-yoghurt fermented mixture, is considered as a good source of saccharides, proteins, some vitamins and minerals. Moreover, their preparation is inexpensive and lactic acid fermentation offers benefi ts like product preservation, enhancement of nutritive value and sensory properties improvement. The aim of this work was to evaluate changes of some chemical parameters during fermentation of tarhana, when the level of salt and amount of yoghurt used were varied. Some functional and sensory characteristics of the fi nal product were also determined. Material and methods. Chemical analysis included determination of pH, titrable acidity, content of reducing saccharides, lactic, acetic and citric acid. Measured functional properties of tarhana powder were foaming capacity, foam stability, water absorption capacity, oil absorption capacity and emulsifying activity. Tarhana soups samples were evaluated for their sensory characteristics (colour, odor, taste, consistency and overall acceptability. Results. Fermentation of tarhana by lactic acid bacteria and yeasts led to decrease in pH, content of reducing saccharides and citric acid, while titrable acidity and concentration of lactic and acetic acid increased. Determination of functional properties of tarhana powder showed, that salt absence and increased amount of yoghurt in tarhana recipe reduced foaming capacity and oil absorption capacity, whereas foam stability and water absorption capacity were improved. Sensory evaluation of tarhana soups showed that variations in tarhana recipe adversly affected sensory parameters of fi nal products. Conclusion. Variations in tarhana recipe (salt absence, increased proportion of yoghurt led to changes in some chemical parameters (pH, titrable acidity, reducing saccharides, content of lactic, acetic and citric acid. Functional properties were also affected with changed tarhana recipe. Sensory characteristics determination showed, that

  15. NIR Spectroscopic Properties of Aqueous Acids Solutions

    Directory of Open Access Journals (Sweden)

    Mohd Zubir MatJafri

    2012-06-01

    Full Text Available Acid content is one of the important quality attributes in determining the maturity index of agricultural product, particularly fruits. Despite the fact that much research on the measurement of acidity in fruits through non-destructive spectroscopy analysis at NIR wavelengths between 700 to 1,000 nm has been conducted, the same response towards individual acids is not well known. This paper presents NIR spectroscopy analysis on aqueous citric, tartaric, malic and oxalic solutions through quantitative analysis by selecting a set of wavelengths that can best be used to measure the pH of the solutions. The aquaphotomics study of the acid solutions has generated R2 above 0.9 for the measurement of all acids. The most important wavelengths for pH are located at 918–925 nm and 990–996 nm, while at 975 nm for water.

  16. Higher pH acid stimulation systems

    Energy Technology Data Exchange (ETDEWEB)

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

    1979-01-01

    Two types of high pH (4 to 6), mild acting acidizing systems developed for in-depth rock matrix stimulation for both sandstone and carbonate reservoirs are described. With these systems, in-depth stimulation capability is available from ambient to about 280 F (138 C). Buffer regulated (BR) systems also have application for near well-bore stimulation at temperatures of up to at least 365 F (185 C). The self-generating systems based on methyl formate (MF), the ammonium salt of monochloroacetic acid (CA), and methyl acetate (MA), have sandstone application ranges and are described. Three BR systems have been developed, based on formic, acetic, and citric acids. Included in the study is a brief review of the theory involved, experimental techniques for measuring acid reaction rates, and discussions of clay dissolution and carbonate acidization mechanisms. 16 references.

  17. Organic acids composition of Cydonia oblonga Miller leaf.

    Science.gov (United States)

    Oliveira, Andreia P; Pereira, José A; Andrade, Paula B; Valentão, Patrícia; Seabra, Rosa M; Silva, Branca M

    2008-11-15

    Organic acid profiles of 36 Cydonia oblonga Miller leaf samples, from three different geographical origins of northern (Bragança and Carrazeda de Ansiães) and central Portugal (Covilhã), harvested in three collection months (June, August and October of 2006), were determined by HPLC/UV (214nm). Quince leaves presented a common organic acid profile, composed of six constituents: oxalic, citric, malic, quinic, shikimic and fumaric acids. C. oblonga leaves total organic acid content varied from 1.6 to 25.8g/kg dry matter (mean value of 10.5g/kg dry matter). Quinic acid was the major compound (72.2%), followed by citric acid (13.6%). Significant differences were found in malic and quinic acids relative abundances and total organic acid contents according to collection time, which indicates a possible use of these compounds as maturity markers. Between June and August seems to be the best period to harvest quince leaves for preparation of decoctions or infusions, since organic acids total content is higher in this season. PMID:26047441

  18. Corrosion of alloy C-22 in organic acid solutions

    International Nuclear Information System (INIS)

    Electrochemical studies such as cyclic potentiodynamic polarization (CPP) and electrochemical impedance spectroscopy (EIS) were performed to determine the corrosion behavior of Alloy 22 (N06022) in 1M NaCl solutions at various pH values from acidic to neutral at 90 C degrees. All the tested material was wrought Mill Annealed (MA). Tests were also performed in NaCl solutions containing weak organic acids such as oxalic, acetic, citric and picric acids. Results show that the corrosion rate of Alloy 22 was significantly higher in solutions containing oxalic acid than in solutions of pure NaCl at the same pH. Citric and Picric acids showed a slightly higher corrosion rate, and Acetic acid maintained the corrosion rate of pure chloride solutions at the same pH. Organic acids revealed to be weak inhibitors for crevice corrosion. Higher concentration ratios, compared to nitrate ions, were needed to completely inhibit crevice corrosion in chloride solutions. Results are discussed considering acid dissociation constants, buffer capacity and complex formation constants of the different weak acids. (author)

  19. Decontamination of media filters in a groundwater treatment plant by dissolution processes using organic acid solutions

    International Nuclear Information System (INIS)

    Ground water was collected from a depth of 1,200 m in the Al-Qasim area in mid-Saudi Arabia. This underground water contains minerals, mainly Fe and Mn and radio-nuclides like radium and other ionic materials. This water was filtered through a sand bed, which contains layers of sands of different sizes in order to remove those impurities from water. Mn and Fe were deposited on outer layer of each sand granule during filtration and radium was adsorbed on surfaces of these minerals. Ra was separated from these minerals by dissolving them in various acids such as ascorbic acid, citric acid, tannic acid, salicylic acid, tartaric acid and lactic acid under different experimental conditions like acid concentration, contact time, shaking speed, particle size, temperature and liquid/solid ratio. The effectiveness of these acids on radium removal was found as follows: ascorbic acidcitric acid > tartaric acid > tannic acid > lactic acid > salicylic acid. Various reaction parameters were also optimized. Reaction kinetic and mechanism parameters of dissolution process were studied and compared with other published data. (author)

  20. The Study of Organic Acids Changes with Different Lactic Acid Starters During Iranian White Brined Cheese Ripening

    Directory of Open Access Journals (Sweden)

    M.B. Habbibi

    2002-04-01

    Full Text Available For Iranian fermented cheese processing and ripening, different lactic acid bacteria (LAB that affect on the physicochemical properties and hence the organoleptic characteristics of the cheese is used. Determination of physicochemical changes of cheese, particularly, organic acids is of importance. In this study five cheese formulas with five different group of cheese starters were processed and ripened in 8% brine during two months at 12±1 °C. HPLC analysis of organic acids were accomplished, using SCR-101H column with U. V. detector at 214 nm and quantified with high purity standards concerning each organic acid recovery. Pyruvic, orotic, citric, propionic, lactic, butyric and acetic acids were analyzed after 1, 10, 20, 30, 40, 50 and 60 days of processing and storage. Each determined organic acid exhibited a specific profile changes during cheese ripening. Lactic acid was dominant organic acid in all samples. Total organic acids were increased significantly after 30 days of storage, but decreased up to the end of ripening. The profile changes of organic acids which was similar in all samples with different amounts related to dominant lactic acid with about 80-90% of the total organic acids. The aromatic mesophile group, CH-N-O1(including Lactococci and Leuconostocs and Lactobacillus casei and also the mixed mesophiles plus thermophile starters group, CH-1 (including Lactobacillus bulgaricus and Streptococcus salivarius ssp. thermophilus caused a significant decrease in citric acid and increase in acetic and propionic acid in related cheese samples compared with other cheeses (P < 0.01. But cheese containing only thermophiles or the mixed thermophile and mesophile (code 54 revealed a significant increase in butyric acid. In all samples the changes in pyruvic acid content was irregular. The ripening period of cheese samples were determined by the stepwise regression analysis in relation to their exact amount of organic acids.

  1. Comparative evaluation of demineralization of radicular dentin with 17% ethylenediaminetetraacetic acid, 10% citric acid, and MTAD at different time intervals: An in vitro study

    OpenAIRE

    Kumar, Yogender; Lohar, Jitendra; Bhat, Sureka; Bhati, Manisha; Gandhi, Aanesh; Mehta, Abhishek

    2016-01-01

    Background: The smear layer has the capability to protect the bacteria within the dentinal tubules from intracanal medicament. After removal of the smear layer from infected root canals, it allows disinfection of the entire root canal. The smear layer compromising the seal between the root canal sealer and root canal wall also decreases the penetration of irrigants into dentinal tubules. Aims: This study compares the amount of phosphorous liberated and demineralization of the radicular dentin...

  2. Purification of organic acids by chromatography with strong anionic resins: Investigation of uptake mechanisms.

    Science.gov (United States)

    Lemaire, Julien; Blanc, Claire-Line; Lutin, Florence; Théoleyre, Marc-André; Stambouli, Moncef; Pareau, Dominique

    2016-08-01

    Bio-based organic acids are promising renewable carbon sources for the chemical industry. However energy-consuming purification processes are used, like distillation or crystallization, to reach high purities required in some applications. That is why preparative chromatography was studied as an alternative separation technique. In a previous work dealing with the purification of lactic, succinic and citric acids, the Langmuir model was insufficient to explain the elution profiles obtained with a strong anionic resin. Consequently the Langmuir model was coupled with a usual ion-exchange model to take into account the retention of their conjugate bases (tailing and apparent delay observed with succinic and citric acids can be explained by the high affinity of succinate and citrate for resin cationic sites. The model was implemented in a preparative chromatography simulation program in order to optimize operating parameters of our pilot-scale ISMB unit (Improved Simulated Moving Bed). The comparison with experimental ISMB profiles was conclusive. PMID:27373374

  3. Uranium leaching using mixed organic acids produced by Aspergillus niger

    International Nuclear Information System (INIS)

    Both of culture temperature and pH value had impacts on the degree of uranium extraction through changing types and concentrations of mixed organic acids produced by Aspergillus niger, and significant interactions existed between them though pH value played a leading role. And with the change of pH value of mixed organic acids, the types and contents of mixed organic acids changed and impacted on the degree of uranium extraction, especially oxalic acid, citric acid and malic acid. The mean degree of uranium extraction rose to peak when the culture temperature was 25 deg C (76.14 %) and pH value of mixed organic acids was 2.3 (82.40 %) respectively. And the highest one was 83.09 %. The optimal culture temperature (25 deg C) of A. niger for uranium leaching was different from the most appropriate growing temperature (37 deg C). (author)

  4. Calcite crystal growth rate inhibition by polycarboxylic acids

    Science.gov (United States)

    Reddy, M.M.; Hoch, A.R.

    2001-01-01

    Calcite crystal growth rates measured in the presence of several polycarboxyclic acids show that tetrahydrofurantetracarboxylic acid (THFTCA) and cyclopentanetetracarboxylic acid (CPTCA) are effective growth rate inhibitors at low solution concentrations (0.01 to 1 mg/L). In contrast, linear polycarbocylic acids (citric acid and tricarballylic acid) had no inhibiting effect on calcite growth rates at concentrations up to 10 mg/L. Calcite crystal growth rate inhibition by cyclic polycarboxyclic acids appears to involve blockage of crystal growth sites on the mineral surface by several carboxylate groups. Growth morphology varied for growth in the absence and in the presence of both THFTCA and CPTCA. More effective growth rate reduction by CPTCA relative to THFTCA suggests that inhibitor carboxylate stereochemical orientation controls calcite surface interaction with carboxylate inhibitors. ?? 20O1 Academic Press.

  5. Analysis of the influence and optimization of concentration of organic acids on chemical and physical properties of wheat dough using a response surface methodology and desirability function

    Directory of Open Access Journals (Sweden)

    Šimurina Olivera D.

    2013-01-01

    Full Text Available In order to improve physical and chemical properties of dough produced from wheat flour of suboptimal quality (protein content 10.7% dry basis, dough energy 4.0 cm2, optimal doses of ascorbic and citric acid were evaluated using a response surface methodology and desirability function. The paper brings the analysis of the main effects as well as their interactions. The effect of organic acids was evident in relation to pH lowering and decrease in free thiol groups, which consequently changed the physical properties of dough (increased dough energy, extensibility and resistance. The well known oxidative effect of ascorbic acid which is manifested as increase in dough energy and resistance, was enhanced by the addition of citric acid i.e. their synergistic action. Contribution of citric acid was the donation of hydrogen ions which changed the pH, lowered the content of free -SH groups and increased protein aggregation. Ascorbic acid individually significantly increased energy (linear regression coefficient b1 = 4.010-4 but higher effect was exerted by the addition of ascorbic and citric acid mixture as seen through higher interaction regression coefficient (b12 = 0.076. Dough resistance was significantly affected only by ascorbic acid due to its oxidizing action whereas dough extensibility was affected by both acids (main effects at all applied doses and their mixtures. The effect on dough extensibility depends on the dose of acids but resistance decreased with quadratic increase of acid doses. Second-order polynomials were used in modeling of responses (dough energy, resistance and extensibility which showed a good fit with experimental data as shown by high values of the coefficients of determination R2 for energy, resistance and extensibility (0.953, 0.976 and 0.996, respectively. Based on F value, it could be concluded that the model gave good prediction of experimental data while p-values for all responses showed that the models were

  6. Biodegradation of acetonitrile by cells of Candida guilliermondii UFMG-Y65 immobilized in alginate, k-carrageenan and citric pectin

    Directory of Open Access Journals (Sweden)

    Dias João Carlos T.

    2000-01-01

    Full Text Available Different encapsulation matrices were tested for immobilized cells of Candida guilliermondii UFMG-Y65 used for acetonitrile degradation. Acetonitrile degradation by free cells and cells immobilized in Ba-alginate, kappa-carrageenan and citric pectin was studied. The rate of acetonitrile degradation was monitored for 120 h by measuring yeast growth and ammonia concentration. Different alginate concentrations did not affect cell viability, but the period of incubation in BaCl2 solution reduced the number of viable cells. Likewise, the gel nature and the matrix structure of the support resulting from the cell immobilization conditions were of fundamental importance for biocatalyst activity and performance, affecting substantially the patterns of microbial growth and enzymatic activity. Alginate-immobilized cells degraded acetonitrile more efficiently than kappa-carrageenan or citric pectin-immobilized cells.

  7. ACIDIC SOAKING AND STEAM BLANCHING RETAIN ANTHOCYANINS AND POLYPHENOLS IN PURPLE Dioscorea alata FLOUR

    Directory of Open Access Journals (Sweden)

    Nelis Imanningsih*

    2013-12-01

    Full Text Available Purple Dioscorea alata (DA tuber has health benefits due to its bioactive anthocyanins, which belong to polyphenolic group. Tuber is commonly made into flour to optimize its uses, however, the anthocyanins undergo significant degradation during processing because of the endogenous polyphenol oxidase activities. This research investigated factors that retain anthocyanins and polyphenols in the purple DA flour as well as its antioxidant capacity. The types of treatments during milling process should be taken into account; for instance, soaking in citric acid and blanching in order to preserve the bioactive compounds. To examine the inhibitory effects of acidic soaking and steam blanching on polyphenol oxidase activities, these experiments used four levels of citric acid (0, 0.25, 0.5, and 1% and two levels of steam blanching time course (5 and 10 minutes. It was found that steam blanching for 5 or 10 minutes could reduce the activity of polyphenol oxidase, and consequently, retard the oxidation process and retain the polyphenolic compounds. Soaking the purple DA slices into a 1% citric acid solution followed by steam blanching for 10 min resulted in the highest total anthocyanins (104.36 mg/100 g, polyphenols (198.52 mg equivalent gallic acid/100 g, with an antioxidant capacity of 1.300 mg trolox equivalent/100 g. This study showed that the retention of bioactive compounds of DA tuber through soaking the tuber slices in solution containing inexpensive chemicals like citric acid at low concentrations, combined with 10 minutes of steam blanching resulted in flour containing total anthocyanins and phenolic as high as 44.51 and 62.58% of fresh tuber, respectively.

  8. One-pot assembly of metal/organic-acid sites on amine-functionalized ligands of MOFs for photocatalytic hydrogen peroxide splitting.

    Science.gov (United States)

    Qin, Lei; Li, Zhaowen; Hu, Qiong; Xu, Zehai; Guo, Xinwen; Zhang, Guoliang

    2016-06-01

    A one-pot organic-acid-directed post-synthetic modification allows molecular iron/citric acid complexes to be anchored into amine-functionalized MOFs by a simple and rapid liquid spraying method. Amidation between organic acid and -NH2 groups of ligands can lead to more small nanoparticles (NPs) that are well-dispersed into MOFs and exhibit high activity for photocatalytic H2O2 splitting. PMID:27166081

  9. Synthesis of poly(acrylic acid-maleic acid)SiO2/Al2O3 as novel composite material for cesium removal from acidic solutions

    International Nuclear Information System (INIS)

    A novel composite material of SiO2-Al2O3 based on poly(acrylic acid-maleic acid) was synthesized by irradiated with 60Co γ-rays at a dose of 25 KGy. The composite material was characterized using FTIR, TGA and BET surface area. Adsorption of 134Cs from HNO3 was studied as a function of contact time, temperature and concentration of Cs. Sorption behavior of 134Cs in different concentration of HCl, HNO3, acetic acid, ascorbic acid, citric acid, NaCl and NaNO3 solutions has been investigated. It can be concluded that the P(AA-MA)/SiO2/Al2O3 is promising adsorbent for Cs removal from acidic liquid radioactive waste. (author)

  10. Dissolution of Aluminum in Variably Charged Soils as Affected by Low-Molecular-Weight Organic Acids

    Institute of Scientific and Technical Information of China (English)

    LI Jiu-Yu; XU Ren-Kou; JI Guo-Liang

    2005-01-01

    Low-molecular-weight (LMW) organic acids exist widely in soils and play an important role in soil processes such as mineral weathering, nutrient mobilization and Al detoxification. In this research, a batch experiment was conducted to examine the effects of LMW organic acids on dissolution of aluminum in two variably charged soils, an Ultisol and an Oxisol. The results showed that the LMW organic acids enhanced the dissolution of Al in the two investigated soils in the following order: citric > oxalic > malonic > malic > tartaric > salicylic > lactic > maleic. This was generally in agreement with the magnitude of the stability constants for the Al-organic complexes. The effects of LMW organic acids on Al dissolution were greater in the Ultisol than in the Oxisol as compared to their controls. Also, the accelerating effects of citric and oxalic acids on dissolution of Al increased with an increase in pH, while the effects of lactic and salicylic acids decreased. Additionally, when the organic acid concentration was less than 0.2 mmol L-1, the dissolution of Al changed little with increase in acid concentration. However, when the organic acid concentration was greater than 0.2 mmol L-1,the dissolution of Al increased with increase in acid concentration. In addition to the acid first dissociation constant and stability constant of Al-organic complexes, the promoting effects of LMW organic acids on dissolution of Al were also related to their sorption-desorption equilibrium in the soils.

  11. Effects of low-molecular-weight organic acids on phosphorus sorption characteristics in some calcareous soils

    OpenAIRE

    MORADI, Neda; SADAGHIANI, Mir Hassan RASOULI; SEPEHR, Ebrahim

    2012-01-01

    Understanding the role of organic acids in phosphorus sorption in soils is very important for economic and environmentally friendly management of soil P. Thus, calcareous surface soils (0-30 cm) from West Azerbaijan Province, Iran, were sampled to study the effect of different organic acids on P sorption. Soil samples (2.5 g) were equilibrated with 25 mL of 0.01 M CaCl2 solution containing 0-20 mg P L-1 and 5 mmol L-1 of different organic acids (citric, oxalic, and malic acid). The sorption d...

  12. Reactive Distillation for Esterification of Bio-based Organic Acids

    Energy Technology Data Exchange (ETDEWEB)

    Fields, Nathan; Miller, Dennis J.; Asthana, Navinchandra S.; Kolah, Aspi K.; Vu, Dung; Lira, Carl T.

    2008-09-23

    The following is the final report of the three year research program to convert organic acids to their ethyl esters using reactive distillation. This report details the complete technical activities of research completed at Michigan State University for the period of October 1, 2003 to September 30, 2006, covering both reactive distillation research and development and the underlying thermodynamic and kinetic data required for successful and rigorous design of reactive distillation esterification processes. Specifically, this project has led to the development of economical, technically viable processes for ethyl lactate, triethyl citrate and diethyl succinate production, and on a larger scale has added to the overall body of knowledge on applying fermentation based organic acids as platform chemicals in the emerging biorefinery. Organic acid esters constitute an attractive class of biorenewable chemicals that are made from corn or other renewable biomass carbohydrate feedstocks and replace analogous petroleum-based compounds, thus lessening U.S. dependence on foreign petroleum and enhancing overall biorefinery viability through production of value-added chemicals in parallel with biofuels production. Further, many of these ester products are candidates for fuel (particularly biodiesel) components, and thus will serve dual roles as both industrial chemicals and fuel enhancers in the emerging bioeconomy. The technical report from MSU is organized around the ethyl esters of four important biorenewables-based acids: lactic acid, citric acid, succinic acid, and propionic acid. Literature background on esterification and reactive distillation has been provided in Section One. Work on lactic acid is covered in Sections Two through Five, citric acid esterification in Sections Six and Seven, succinic acid in Section Eight, and propionic acid in Section Nine. Section Ten covers modeling of ester and organic acid vapor pressure properties using the SPEAD (Step Potential

  13. Wheat-Exuded Organic Acids Influence Zinc Release from Calcareous Soils

    Institute of Scientific and Technical Information of China (English)

    M. A. MAQSOOD; S. HUSSAIN; T. AZIZ; M. ASHRAF

    2011-01-01

    Rhizosphere drives plant uptake of sparingly soluble soil zinc (Zn).An investigation with three experiments was conducted to study organic acid exudation by two contrasting wheat genotypes (Sehar-06 and Vatan),Zn fractious in 10 different calcareous soils from Punjab,Pakistan,and release of different soil Zn fractions by organic acids.The two genotypes differed significantly in biomass production and Zn accumulation under deficient and optimum Zn levels in nutrient solution.At a deficient Zn level,Sehar-06 released more maleic acid in the rhizosphere than Vatan.Ten soils used in the present study had very different physicochemical properties; their total Zn and Zn distribution among different fractions varied significantly.Zinc release behaviour was determined by extracting the soils with 0.005 mol L-1 citric acid or maleic acid.The parabolic diffusion model best described Zn release as a function of time.Parabolic diffusion model fitting indicated more maleic acid-driven than citric acid-driven soil Zn mobility from different fractions.Cumulative Zn release in six consecutive extractions during 24 h ranged from 1.85 to 13.58 mg kg-1 using maleic acid and from 0.37 to 11.84 mg kg-1 using citric acid.In the selected calcareous soils,the results of stepwise linear regression indicated significant release of Fe-Mn oxide-bounded soil Zn by maleic acid and its availability to the Zn-efficient genotype.Hence,release of maleic acid by plants roots played an important role in phytoavailability of Zn from calcareous soils.

  14. Inhibition of ice crystallisation in highly viscous aqueous organic acid droplets

    Directory of Open Access Journals (Sweden)

    B. J. Murray

    2008-05-01

    Full Text Available Homogeneous nucleation of ice within aqueous solution droplets and their subsequent crystallisation is thought to play a significant role in upper tropospheric ice cloud formation. It is normally assumed that homogeneous nucleation will take place at a threshold supersaturation, irrespective of the identity of the solute, and that rapid growth of ice particles will follow immediately after nucleation. However, it is shown here through laboratory experiments that droplets may not readily freeze in the very cold tropical tropopause layer (TTL, typical temperatures of 186–200 K. In these experiments ice crystal growth in citric acid solution droplets did not occur when ice nucleated below 197±6 K. Citric acid, 2-hydroxypropane-1,2,3-tricarboxyllic acid, is a molecule with similar functionality to oxygenated organic compounds which are ubiquitous to atmospheric aerosol and is therefore thought to be a sensible proxy for atmospheric organic material. Evidence is presented that suggest citric acid solution droplets become ultra-viscous or perhaps even glassy under atmospherically relevant conditions. Diffusion of liquid water molecules to ice nuclei is expected to be very slow in ultra-viscous solution droplets and this most likely provides an explanation for the experimentally observed inhibition of ice crystallisation. The implications of ultra-viscous solution droplets for ice cloud formation and supersaturations in the TTL are discussed.

  15. Inhibition of ice crystallisation in highly viscous aqueous organic acid droplets

    Directory of Open Access Journals (Sweden)

    B. J. Murray

    2008-09-01

    Full Text Available Homogeneous nucleation of ice within aqueous solution droplets and their subsequent crystallisation is thought to play a significant role in upper tropospheric ice cloud formation. It is normally assumed that homogeneous nucleation will take place at a threshold supersaturation, irrespective of the identity of the solute, and that rapid growth of ice particles will follow immediately after nucleation. However, it is shown here through laboratory experiments that droplets may not readily freeze in the very cold tropical tropopause layer (TTL, typical temperatures of 186–200 K. In these experiments ice crystal growth in citric acid solution droplets did not occur when ice nucleated below 197±6 K. Citric acid, 2-hydroxypropane-1,2,3-tricarboxyllic acid, is a molecule with similar functionality to oxygenated organic compounds which are ubiquitous in atmospheric aerosol. It is therefore thought to be a sensible proxy for atmospheric organic material. Evidence is presented that suggests citric acid solution droplets become ultra-viscous and form glassy solids under atmospherically relevant conditions. Diffusion of liquid water molecules to ice nuclei is expected to be very slow in ultra-viscous solution droplets and nucleation is negligible in glassy droplets; this most likely provides an explanation for the experimentally observed inhibition of ice crystallisation. The implications of ultra-viscous and glassy solution droplets for ice cloud formation and supersaturations in the TTL are discussed.

  16. Radiolytic degradation of sorbic acid in isolated systems

    International Nuclear Information System (INIS)

    Effect of Co(60) gamma-irradiation on stability of sorbic acid (SA) in solutions, dough and chapaties has been investigated. SA was highly susceptible to radiolytic degradation in aqueous systems. Rate of degradation decreased with rise in pH. Sugars, hydrocolloids except pectin, citric acid, lactic acid, malic acid, arginine and threonine, catalyzed degradation while oxalic acid, maleic acid, Cu2+, nitrite, nitrate and phthalate had protective effects. SA was more stable in alcohols and vegetable oils than in aqueous solutions. In wheat flour radiolytic degradation of SA was less at lower moisture. Relatively SA was more stable in chapaties than in dough. Gelatinization and addition of oil in dough reduced degradation of SA

  17. CHANGES IN THE CHARDONNAY CLONES ORGANIC ACIDS RATIO DURING MATURATION TIME

    Directory of Open Access Journals (Sweden)

    Ana Jeromel

    2007-12-01

    Full Text Available Tartaric and malic acids are essential constituents of grape must and wine, contributing directly to its taste as well as balancing with other flavors. High temperature conditions during maturation time can strongly affect malic acid/tartaric acid ratio resulting in a lower acid content due to increasing degradation of malic acid. In the 2006 year Chardonnay grape (clone SMA 130, CL 95, CL96, CL548, SMA 123, R8, VCR10 from Zagreb wine region was collected every 3-5 days from the moment of verasion until the harvest time. The smallest malic acid/tartaric acid ratio was detected in CL 95 clone while clone CL 96 and VCR10 had the highest malic acid/tartaric acid ratio. There was no difference in the citric acid content among tested clones.

  18. Organic Acid Production by Filamentous Fungi

    Energy Technology Data Exchange (ETDEWEB)

    Magnuson, Jon K.; Lasure, Linda L.

    2004-05-03

    Many of the commercial production processes for organic acids are excellent examples of fungal biotechnology. However, unlike penicillin, the organic acids have had a less visible impact on human well-being. Indeed, organic acid fermentations are often not even identified as fungal bioprocesses, having been overshadowed by the successful deployment of the β-lactam processes. Yet, in terms of productivity, fungal organic acid processes may be the best examples of all. For example, commercial processes using Aspergillus niger in aerated stirred-tank-reactors can convert glucose to citric acid with greater than 80% efficiency and at final concentrations in hundreds of grams per liter. Surprisingly, this phenomenal productivity has been the object of relatively few research programs. Perhaps a greater understanding of this extraordinary capacity of filamentous fungi to produce organic acids in high concentrations will allow greater exploitation of these organisms via application of new knowledge in this era of genomics-based biotechnology. In this chapter, we will explore the biochemistry and modern genetic aspects of the current and potential commercial processes for making organic acids. The organisms involved, with a few exceptions, are filamentous fungi, and this review is limited to that group. Although yeasts including Saccharomyces cerevisiae, species of Rhodotorula, Pichia, and Hansenula are important organisms in fungal biotechnology, they have not been significant for commercial organic acid production, with one exception. The yeast, Yarrowia lipolytica, and related yeast species, may be in use commercially to produce citric acid (Lopez-Garcia, 2002). Furthermore, in the near future engineered yeasts may provide new commercial processes to make lactic acid (Porro, Bianchi, Ranzi, Frontali, Vai, Winkler, & Alberghina, 2002). This chapter is divided into two parts. The first contains a review of the commercial aspects of current and potential large

  19. Casein Films: The Effects of Formulation, Environmental Conditions and the Addition of Citric Pectin on the Structure and Mechanical Properties

    Directory of Open Access Journals (Sweden)

    Laetitia M. Bonnaillie

    2014-07-01

    Full Text Available Thin casein films for food packaging applications reportedly possess good strength and low oxygen permeability, but low elasticity and high sensitivity to moisture. Modifying the films to target specific behaviors depending on environmental conditions can enable a variety of commercial applications for casein-based films. The mechanical properties of solvent-cast (15% solids calcium-caseinate/glycerol films (CaCas:Gly ratio of 3:1 were characterized as a function of processing and environmental conditions, including film thickness, solution formulation and ambient humidity (from 22% to 70% relative humidity (RH at ~20 °C. At constant RH, the elongation at break (EAB had a strong positive dependence on the film thickness. When RH increased, the tensile strength (TS and modulus (E decreased approximately linearly, while EAB increased. From 0.05% to 1% (w/w of citric pectin (CP was then incorporated into CaCas/Gly films following seven different formulations (mixing sequences, to alter the protein network and to evaluate the effects of CP on the tensile properties of CaCas/Gly/CP films. At constant film thickness and ~60% RH, the addition of 0.1% or 1.0% CP to the films considerably increased or decreased EAB, TS and E in different directions and to different extents, depending on the formulation, while optical micrographs also showed vastly differing network configurations, suggesting complex formulation- and stoichiometry-dependent casein-pectin interactions within the dried films. Depending on the desired film properties and utilization conditions, pectin may be a useful addition to casein film formulations for food packaging applications.

  20. HPLC Organic Acid Analysis in Different Citrus Juices under Reversed Phase Conditions

    Directory of Open Access Journals (Sweden)

    Violeta NOUR

    2010-06-01

    Full Text Available A reversed phase HPLC method for separation and quantification of organic acids (oxalic, citric, tartaric, malic, ascorbic and lactic acids in fruit juices was developed. The chromatographic separation was performed with a Surveyor Thermo Electron system at 10C by using potassium dihydrogen orthophosphate buffer (pH 2.8 as mobile phase, an Hypersil Gold aQ Analytical Column and diode array detection at ?=254 nm for ascorbic acid and ?=214 nm for the other organic acids. Organic acid profiles of ten species of Citrus: sweet orange, minneola, clementine, mandarin orange, pomelo, lemon, lime, sweetie, white and pink grapefruit were established. Species significantly affect the organic acid distribution of citrus fruit juices. In all citrus juices, the most abundant organic acid was citric acid, ranging from 6.88 to 73.93 g/l. Citrus juices are good sources of ascorbic acid (0.215-0.718 g/l. Average ascorbic acid was the highest in lemon juice followed by sweet orange juice, sweetie and white grapefruit.

  1. Fabrication, structure and biological properties of organic acid-derived sol-gel bioactive glasses

    International Nuclear Information System (INIS)

    Sol-gel-derived bioactive glasses (BGs) have been developed for bone tissue regeneration. To develop more reliable bone tissue repair systems, it is necessary to control the morphology and surface textures of bioactive glasses. In this study, we prepared bioactive glasses by sol-gel technology using hydrochloride acid, lactic acid, citric acid and acetic acid as hydrolysis catalysts. We studied effects of acids on the morphology and surface textures, apatite-forming bioactivity and cellular response (cellular attachment and proliferation) of BGs. Results showed that the surface morphology, structure, apatite-forming bioactivity and cellular response of BG particles can be controlled by changing acid species. The hydrochloric acid-derived bioactive glass (HBG) and the acetic acid-derived bioactive glass (ABG) present high surface areas and fast apatite-forming rates. Lactic acid- and citric acid-derived bioactive glasses (LBG, CBG) exhibited nanoscale surface morphology, relatively low surface areas and comparable apatite-forming bioactivity. The results of human marrow mesenchymal stem cell (HMSC) culture exhibited that LBG and CBG have an enhanced effect on the cell proliferation, as compared to HBG, ABG and tissue culture plate. This study suggests that sol-gel bioactive glasses with proper surface textures and apatite-forming rate can affect preliminary cellular proliferation.

  2. Changes of organic acids content during the fermentation of mulberry wine%桑椹酒发酵过程中有机酸含量变化

    Institute of Scientific and Technical Information of China (English)

    商敬敏; 牟京霞; 孟庆山; 邓波; 张家荣; 史涛涛; 赵新节

    2012-01-01

    利用高效液相色谱法测定桑椹酒发酵过程中七种有机酸的变化,结果显示:桑椹原果汁中琥珀酸含量最高,柠檬酸次之;发酵过程中酒石酸、苹果酸、柠檬酸、琥珀酸、草酸、抗坏血酸含量变化均先呈上升趋势,达到最大值后呈下降趋势,而乳酸含量则一直上升;发酵结束后检测到酒石酸、苹果酸、柠檬酸、琥珀酸、草酸、抗坏血酸、乳酸含量分别为1.822、2.54、2.44、0.76、0.772、0.0756、0.0846g/L。%Seven kinds of organic acids were determined by using high performance liquid chromatography(HPLC) during the fermentation of mulberry wine.The results showed that the content of succinic acid in raw mulberry juice was the highest and followed by citric acid.The content of tartaric acid,malic acid,citric acid,succinic acid,oxalic acid,ascorbic acid increased at first and decreased after reached the maximum.However,lactic acid increased all the time during the whole fermentation.The contents tested of tartaric acid,malic acid,citric acid,succinic acid,oxalic acid,ascorbic acid,lactic acid after the end of fermentation was 1.822,2.54,2.44,0.76,0.772,0.0756 and 0.0846g/L,respectively.

  3. A new alternative to produce gibberellic acid by solid state fermentation

    OpenAIRE

    Cristine Rodrigues; Luciana Porto de Souza Vandenberghe; Juliana Teodoro; Juliana Fraron Oss; Ashok Pandey; Carlos Ricardo Soccol

    2009-01-01

    Gibberellic acid (GA3) is an important hormone, which controls plant's growth and development. Solid State Fermentation (SSF) allows the use of agro-industrial residues reducing the production costs. The screening of strains (four of Gibberella fujikuoroi and one of Fusarium moniliforme) and substrates (citric pulp, soy bran, sugarcane bagasse, soy husk, cassava bagasse and coffee husk) and inoculum preparation study were conducted in order to evaluate the best conditions to produce GA3 by SS...

  4. Cd and Ni transport and accumulation in the halophyte Sesuvium portulacastrum: implication of organic acids in these processes.

    Science.gov (United States)

    Mnasri, Mejda; Ghabriche, Rim; Fourati, Emna; Zaier, Hanen; Sabally, Kebba; Barrington, Suzelle; Lutts, Stanley; Abdelly, Chedly; Ghnaya, Tahar

    2015-01-01

    The implication of organic acids in Cd and Ni translocation was studied in the halophyte species Sesuvium portulacastrum. Citric, fumaric, malic, and ascorbic acids were separated and quantified by HPLC technique in shoots, roots and xylem saps of plants grown on nutrient solutions added with 50 μM Cd, 100 μM Ni and the combination of 50 μM Cd + 100 μM Ni. Results showed that Cd had no significant impact on biomass production while Ni and the combination of both metals drastically affected plant development. Cadmium and Ni concentrations in tissues and xylem sap were higher in plants subjected to individual metal application than those subjected to the combined effect of Cd and Ni suggesting a possible competition between these metals for absorption. Both metals applied separately or in combination induced an increase in citrate concentration in shoots and xylem sap but a decrease of this concentration in the roots. However, a minor relationship was observed between metal application and fumaric, malic, and ascorbic acids. Both observations suggest the implication of citric acid in Cd, Ni translocation and shoot accumulation in S. portulacastrum. The relatively high accumulation of citric acid in xylem sap and shoot of S. portulacastrum could be involved in metal chelation and thus contributes to heavy metal tolerance in this species. PMID:25821455

  5. Cd and Ni transport and accumulation in the halophyte Sesuvium portulacastrum: implication of organic acids in these processes

    Directory of Open Access Journals (Sweden)

    Tahar eGhnaya

    2015-03-01

    Full Text Available The implication of organic acids in Cd and Ni translocation was studied in the halophyte species Sesuvium portulacastrum. Citric, fumaric, malic and ascorbic acids were separated and quantified by HPLC technique in shoots, roots and xylem saps of plants grown on nutrient solutions added with 50 µM Cd, 100 µM Ni and the combination of 50 µM Cd + 100 µM Ni. Results showed that Cd had no significant impact on biomass production while Ni and the combination of both metals drastically affected plant development. Cadmium and Ni concentrations in tissues and xylem sap were higher in plants individually exposed to heavy metal application than in those subjected to the combined treatment Cd + Ni, suggesting a possible competition between these metals for absorption. Both metals applied separately or in combination induced an increase in citrate concentration in shoots and xylem sap but a decrease of this concentration in the roots. However a minor relationship was observed between metal application and fumaric, malic and ascorbic acids. Both observations suggest the implication of citric acid in Cd, Ni translocation and shoot accumulation in S. portulacastrum. The relatively high accumulation of citric acid in xylem sap and shoot of S. portulacastrum could be involved in metal chelation and thus contributes to heavy metal tolerance in this species.

  6. Acidic organic compounds in beverage, food, and feed production.

    Science.gov (United States)

    Quitmann, Hendrich; Fan, Rong; Czermak, Peter

    2014-01-01

    Organic acids and their derivatives are frequently used in beverage, food, and feed production. Acidic additives may act as buffers to regulate acidity, antioxidants, preservatives, flavor enhancers, and sequestrants. Beneficial effects on animal health and growth performance have been observed when using acidic substances as feed additives. Organic acids could be classified in groups according to their chemical structure. Each group of organic acids has its own specific properties and is used for different applications. Organic acids with low molecular weight (e.g. acetic acid, lactic acid, and citric acid), which are part of the primary metabolism, are often produced by fermentation. Others are produced more economically by chemical synthesis based on petrochemical raw materials on an industrial scale (e.g. formic acid, propionic and benzoic acid). Biotechnology-based production is of interest due to legislation, consumer demand for natural ingredients, and increasing environmental awareness. In the United States, for example, biocatalytically produced esters for food applications can be labeled as "natural," whereas identical conventional acid catalyst-based molecules cannot. Natural esters command a price several times that of non-natural esters. Biotechnological routes need to be optimized regarding raw materials and yield, microorganisms, and recovery methods. New bioprocesses are being developed for organic acids, which are at this time commercially produced by chemical synthesis. Moreover, new organic acids that could be produced with biotechnological methods are under investigation for food applications. PMID:24275825

  7. Otimização e validação de método para determinação de ácidos orgânicos em vinhos por cromatografia líquida de alta eficiência Optimization and validation method for organic acid determination in wines by high performance liquid cromatography

    OpenAIRE

    Luciana L. de Andrade Lima; Alexandre Schuler; Nonete Barbosa Guerra; Giuliano Elias Pereira; Taciana L. de Andrade Lima; Helena Rocha

    2010-01-01

    The organic acids (tartaric, malic, citric, lactic and succinic) are de main components responsible for the acidity in the wine. This method for simultaneous determination of organic acids and interfering peaks in wines can be achieved in 16 min. The sample preceded by a dilution and filtration step. The chromatographic separation required one reversed phase column, isocratic mobile phase (acetonitrila, formic acid in water) and detection wavelength was set at 212 nm. The validation confirmed...

  8. Preliminary study of insect attraction by a mixture of semiochemicals containing 1,2,4-Trimethoxybenzene in domestic citric-culture

    International Nuclear Information System (INIS)

    In this work we describe a new efficient strategy for the preparation of 1,2,4-trimethoxybenzene (3) in 56% overall yield. The compound 3 was used in a preliminary study of insect attraction by a mixture of semiochemicals called TIV, composed of indol (1), vanillin (2) and 1,2,4-trimethoxybenzene (3), in eight Mc Phail style traps installed at a domestic orchard of citric-culture, containing 120 trees not infected by plagues in Bom Jesus Farm, located next to a patch of the Atlantic Forest, at Silva Jardim, Rio de Janeiro, Brazil. (author)

  9. Preliminary study of insect attraction by a mixture of semiochemicals containing 1,2,4-Trimethoxybenzene in domestic citric-culture

    Directory of Open Access Journals (Sweden)

    Ana Paula L. Alves

    2010-01-01

    Full Text Available In this work we describe a new efficient strategy for the preparation of 1,2,4-trimethoxybenzene (3 in 56% overall yield. The compound 3 was used in a preliminary study of insect attraction by a mixture of semiochemicals called TIV, composed of indol (1, vanillin (2 and 1,2,4-trimethoxybenzene (3, in eight Mc Phail style traps installed at a domestic orchard of citric-culture, containing 120 trees not infected by plagues in Bom Jesus Farm, located next to a patch of the Atlantic Forest, at Silva Jardim, Rio de Janeiro, Brazil.

  10. Preliminary study of insect attraction by a mixture of semiochemicals containing 1,2,4-Trimethoxybenzene in domestic citric-culture

    Energy Technology Data Exchange (ETDEWEB)

    Alves, Ana Paula L.; CJunior, Jose Augusto B. de; Slana, Glaucia B. A.; Cardoso, Jari N.; Lopes, Rosangela S. C.; Lopes, Claudio C. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Inst. de Quimica. Dept. de Quimica Analitica

    2010-07-01

    In this work we describe a new efficient strategy for the preparation of 1,2,4-trimethoxybenzene (3) in 56% overall yield. The compound 3 was used in a preliminary study of insect attraction by a mixture of semiochemicals called TIV, composed of indol (1), vanillin (2) and 1,2,4-trimethoxybenzene (3), in eight Mc Phail style traps installed at a domestic orchard of citric-culture, containing 120 trees not infected by plagues in Bom Jesus Farm, located next to a patch of the Atlantic Forest, at Silva Jardim, Rio de Janeiro, Brazil. (author)

  11. Migration of Toxic Metals from Ceramic Food Packaging Materials into Acid Food Simulants

    OpenAIRE

    Zhanhua Dong; Lixin Lu; Zhigang Liu; Yali Tang; Jun Wang

    2014-01-01

    Long-term extraction experiments were carried out on glazed tile specimens with 4 and 10% (v/v) acetic acid, 1% (w/v) citric acid, and 1% (v/v) lactic acid solution in three temperature conditions (20, 40, and 60°C) to investigate the effect of temperature and pH value on extraction of lead, cobalt, nickel, and zinc from ceramic food packaging materials and to study the extraction kinetics of toxic metals. Results showed that except at 60°C the amount of extraction of lead, cobalt, nickel, an...

  12. A thermostable Salmonella phage endolysin, Lys68, with broad bactericidal properties against gram-negative pathogens in presence of weak acids.

    Directory of Open Access Journals (Sweden)

    Hugo Oliveira

    Full Text Available Resistance rates are increasing among several problematic Gram-negative pathogens, a fact that has encouraged the development of new antimicrobial agents. This paper characterizes a Salmonella phage endolysin (Lys68 and demonstrates its potential antimicrobial effectiveness when combined with organic acids towards Gram-negative pathogens. Biochemical characterization reveals that Lys68 is more active at pH 7.0, maintaining 76.7% of its activity when stored at 4°C for two months. Thermostability tests showed that Lys68 is only completely inactivated upon exposure to 100°C for 30 min, and circular dichroism analysis demonstrated the ability to refold into its original conformation upon thermal denaturation. It was shown that Lys68 is able to lyse a wide panel of Gram-negative bacteria (13 different species in combination with the outer membrane permeabilizers EDTA, citric and malic acid. While the EDTA/Lys68 combination only inactivated Pseudomonas strains, the use of citric or malic acid broadened Lys68 antibacterial effect to other Gram-negative pathogens (lytic activity against 9 and 11 species, respectively. Particularly against Salmonella Typhimurium LT2, the combinatory effect of malic or citric acid with Lys68 led to approximately 3 to 5 log reductions in bacterial load/CFUs after 2 hours, respectively, and was also able to reduce stationary-phase cells and bacterial biofilms by approximately 1 log. The broad killing capacity of malic/citric acid-Lys68 is explained by the destabilization and major disruptions of the cell outer membrane integrity due to the acidity caused by the organic acids and a relatively high muralytic activity of Lys68 at low pH. Lys68 demonstrates good (thermostability properties that combined with different outer membrane permeabilizers, could become useful to combat Gram-negative pathogens in agricultural, food and medical industry.

  13. Keto-acids in Carbonaceous Meteorites

    Science.gov (United States)

    Cooper, G.; Chang, P. M.; Dugas, A.; Byrd, A.; Chang, P. M.; Washington, N.

    2005-01-01

    The Murchison and Murray meteorites are the best-characterized carbonaceous meteorites with respect to organic chemistry and are generally used as references for organic compounds in extraterrestrial material. Among the classes of organic compounds found in these meteorites are amino acids, carboxylic acids, hydroxy acids, purines, and pyrimidines. Such compounds, important in contemporary biochemistry, are thought to have been delivered to the early Earth in asteroids and comets and may have played a role in early life and/or the origin of life. Absent among (today's) critically important biological compounds reported in carbonaceous meteorites are keto acids, i.e., pyruvic acid, acetoacetic acid, and higher homologs. These compounds are key intermediates in such critical processes as glycolysis and the citric acid cycle. In this study several individual meteoritic keto acids were identified by gas chromatography-mass spectrometry (GC-MS) (see figure below). All compounds were identified as their trimethylsilyl (TMS), isopropyl ester (ISP), and tert-butyldimethylsilyl (tBDMS) derivatives. In general, the compounds follow the abiotic synthesis pattern of other known meteorite classes of organic compounds [1,2]: a general decrease in abundance with increasing carbon number within a class of compounds and many, if not all, possible isomers present at a given carbon number. The majority of the shown compounds was positively identified by comparison of their mass spectra to commercially available standards or synthesized standards.

  14. Impact of the in situ formed salivary pellicle on enamel and dentine erosion induced by different acids

    OpenAIRE

    Wiegand, A.; Bliggenstorfer, S; Magalhães, A C; Sener, B.; Attin, T.

    2008-01-01

    OBJECTIVE: To investigate and compare the protective impact of the in situ formed salivary pellicle on enamel and dentine erosion caused by different acids at pH 2.6. METHODS: Bovine enamel and dentine samples were exposed for 120 min in the oral cavity of 10 healthy volunteers. Subsequently, enamel and dentine pellicle-covered specimens were extraorally immersed in 1 ml hydrochloric, citric or phosphoric acid (pH 2.6, 60 s, each acid n=30 samples). Pellicle-free samples (each acid n=10) serv...

  15. Effects of organic acids on cadmium and copper sorption and desorption by two calcareous soils.

    Science.gov (United States)

    Najafi, Sarvenaz; Jalali, Mohsen

    2015-09-01

    Low molecular weight organic acids (LMWOAs) present in soil alter equilibrium pH of soil, and consequently, affect heavy metal sorption and desorption on soil constitutes. This study was conducted to investigate the effects of different concentrations (0.1, 1, 2.5, 5, 10, 30, 40, 50, 70, and 100 mM) of citric, malic, and oxalic acids on sorption and desorption of cadmium (Cd) and copper (Cu) in two calcareous soils. Increasing the concentrations of three LMWOAs decreased the equilibrium pH of soil solutions. The results indicated that increase in organic acids concentrations generally reduced Cd and Cu sorption in soils. Increase concentrations of LMWOAs generally promoted Cd and Cu desorption from soils. A valley-like curve was observed for desorption of Cu after the citric acid concentration increment in soil 2. Increasing the concentrations of three LMWOAs caused a marked decrease in Kd(sorp) values of Cd and Cu in soils. In general, citric acid was the most effective organic acid in reducing sorption and increasing desorption of both metals, and oxalic acid had the minimal impact. The results indicated that LMWOAs had a greater impact on Cu sorption and desorption than Cd, which can be attributed to higher stability constants of organic acids complexes with Cu compared to Cd. It can be concluded that by selecting suitable type and concentration of LMWOAs, mobility, and hence, bioavailability of heavy metals can be changed. So, environmental implications concerning heavy metals mobility might be derived from these findings. PMID:26298186

  16. Enhanced Extracorporeal CO2 Removal by Regional Blood Acidification: Effect of Infusion of Three Metabolizable Acids.

    Science.gov (United States)

    Scaravilli, Vittorio; Kreyer, Stefan; Linden, Katharina; Belenkiy, Slava; Pesenti, Antonio; Zanella, Alberto; Cancio, Leopoldo C; Batchinsky, Andriy I

    2015-01-01

    Acidification of blood entering a membrane lung (ML) with lactic acid enhances CO2 removal (VCO2ML). We compared the effects of infusion of acetic, citric, and lactic acids on VCO2ML. Three sheep were connected to a custom-made circuit, consisting of a Hemolung device (Alung Technologies, Pittsburgh, PA), a hemofilter (NxStage, NxStage Medical, Lawrence, MA), and a peristaltic pump recirculating ultrafiltrate before the ML. Blood flow was set at 250 ml/min, gas flow (GF) at 10 L/min, and recirculating ultrafiltrate flow at 100 ml/min. Acetic (4.4 M), citric (0.4 M), or lactic (4.4 M) acids were infused in the ultrafiltrate at 1.5 mEq/min, for 2 hours each, in randomized fashion. VCO2ML was measured by the Hemolung built-in capnometer. Circuit and arterial blood gas samples were collected at baseline and during acid infusion. Hemodynamics and ventilation were monitored. Acetic, citric, or lactic acids similarly enhanced VCO2ML (+35%), from 37.4 ± 3.6 to 50.6 ± 7.4, 49.8 ± 5.6, and 52.0 ± 8.2 ml/min, respectively. Acids similarly decreased pH, increased pCO2, and reduced HCO3 of the post-acid extracorporeal blood sample. No significant effects on arterial gas values, ventilation, or hemodynamics were observed. In conclusion, it is possible to increase VCO2ML by more than one-third using any one of the three metabolizable acids. PMID:26273934

  17. Incorporation of alpha-Ketoglutaric Acid as a Fixed Bed Scrubber Media for the Neutralization of Hydrazine Family Hypergolic Fuels

    Science.gov (United States)

    DeVor, R. W.; Santiago-Maldonado, E.; Parkerson, J. K.

    2010-01-01

    A candidate scrubber media, alpha-ketoglutaric acid (aKGA) adsorbed onto a silica-based substrate was examined as a potential alternative to the hydrazine-family hypergolic fuel neutralization techniques currently utilized at NASA/Kennedy Space Center (KSC). Helvenson et. al. has indicated that aKGA will react with hydrazines to produce non-hazardous, possibly biodegradable products. Furthermore, the authors have previously tested and demonstrated the use of aKGA aqueous solutions as a replacement neutralizing agent for citric acid, which is currently used as a scrubbing agent in liquid scrubbers at KSC. Specific properties examined include reaction efficiency, the loading capacity of aKGA onto various silica substrates, and the comparison of aKGA media performance to that of the citric acid vapor scrubber systems at KSC and a commercial vapor scrubber media. Preliminary investigations showed hydrophobic aerogel particles to be an ideal substrate for the deposition of the aKGA. Current studies have shown that the laboratory produced aKGA-Aerogel absorbent media are more efficient and cost effective than a commercially available fixed bed scrubber media, although much less cost effective than liquid-based citric acid scrubbers (although possibly safer and less labor intensive). A comparison of all three alternative scrubber technologies (liquid aKGA, solid-phase aKGA, and commercially available sorbent materials) is given considering both hypergolic neutralization capabilities and relative costs (as compared to the current citric acid scrubbing technology in use at NASA/KSC).

  18. Application of edible coating and acidic washing for extending the storage life of mushrooms (Agaricus bisporus).

    Science.gov (United States)

    Sedaghat, Naser; Zahedi, Younes

    2012-12-01

    Hydrocolloid-based materials have been extensively used to coat fruit and vegetables to prolong shelf-life. The effects of different concentrations of acidic washing (acetic, ascorbic, citric and malic acids) followed by coating with gum arabic (GA), carboxymethyl cellulose and emulsified gum arabic (EGA) were evaluated on the weight loss (WL), firmness and color of mushroom. The WL of the uncoated mushrooms was significantly (p < 0.05) greater than that of the coated ones, and the minimum WL was obtained with EGA coating. The mushrooms washed with malic and ascorbic acids showed minimum and maximum of WL, respectively. Loss in firmness of the EGA-coated mushrooms was by 21% (the minimum of loss), while loss value of the uncoated ones was by 39% (the maximum of loss). Firmness of mushrooms was not influenced by the acid type. Concentration of the acid significantly (p < 0.05) influenced the firmness of mushrooms, and at the lowest concentration of acid (1%), the mushrooms tissue was firmest. The L* value of the mushrooms coated with GA was higher than that of others. A significant (p < 0.05) decrease in L* value and a significant (p < 0.05) increase in a* and b* values occurred in the mushrooms washed with acetic acid. Overall, washing with 1% citric or malic acid followed by coating with EGA resulted in minimum decrease in WL and firmness of the mushrooms. PMID:23175781

  19. Thermal quenching mechanisms of the Eu3+ luminescence in Ca9Al(PO4)7 obtained by citric route

    International Nuclear Information System (INIS)

    Graphical abstract: Display Omitted Highlights: ► Convenient citric route was used for preparation of the Ca9Al(PO4)7:Eu3+ powders. ► We found that the thermal dependency of the Eu3+ emission shows two different temperature ranges. ► 80% of Eu3+ luminescence intensity is kept at 430 K. ► The possible quenching pathways were constructed using simplified one coordinate energy diagram. -- Abstract: The citric route was employed for synthesis of the pure phase Ca9Al(PO4)7:Eu3+ (CAlP:Eu3+) powders as an attractive alternative to the solid state reaction (no need of multistep and long thermal treatment). Structural properties of the final product were studied by means of X-ray diffraction as well as Rietveld refinement was conducted in order to calculate the cell parameters. The thermal behavior of the emission was studied using excitation line well matched with the 7F0 → 5D4 absorption band covering broad range of temperature. Activation energy was estimated to be equal to 10,550 cm−1. The thermal behavior of the Eu3+ luminescence in CAlP crystal lattice shown that the almost 80% of intensity is kept up to 430 K.

  20. Ligand-enhanced electrokinetic remediation of metal-contaminated marine sediments with high acid buffering capacity.

    Science.gov (United States)

    Masi, Matteo; Iannelli, Renato; Losito, Gabriella

    2016-06-01

    The suitability of electrokinetic remediation for removing heavy metals from dredged marine sediments with high acid buffering capacity was investigated. Laboratory-scale electrokinetic remediation experiments were carried out by applying two different voltage gradients to the sediment (0.5 and 0.8 V/cm) while circulating water or two different chelating agents at the electrode compartments. Tap water, 0.1 M citric acid and 0.1 M ethylenediaminetetraacetic acid (EDTA) solutions were used respectively. The investigated metals were Zn, Pb, V, Ni and Cu. In the unenhanced experiment, the acid front could not propagate due to the high acid buffering capacity of the sediments; the production of OH(-) ions at the cathode resulted in a high-pH environment causing the precipitation of CaCO3 and metal hydroxides. The use of citric acid prevented the formation of precipitates, but solubilisation and mobilisation of metal species were not sufficiently achieved. Metal removal was relevant when EDTA was used as the conditioning agent, and the electric potential was raised up to 0.8 V/cm. EDTA led to the formation of negatively charged complexes with metals which migrated towards the anode compartment by electromigration. This result shows that metal removal from sediments with high acid buffering capacity may be achieved by enhancing the electrokinetic process by EDTA addition when the acidification of the medium is not economically and/or environmentally sustainable. PMID:26490900

  1. Mobilization of Phosphorus by Naturally Occurring Organic Acids in Oxisols and Ultisols

    Institute of Scientific and Technical Information of China (English)

    HANXING-GUO; C.F.JORDAN; 等

    1995-01-01

    Citric and malic acids at concentrations of 0.1,1.0,10,and 100 mmol/L were added to three Ultisols and one Oxisol,The amount of P in solution increased with increasing organic acid concentrations,while the amount of Fe-and Al-bound P decreased.This result suggested that naturally occurring products of organicmatter decomposition could increase the P availability to plants in soils where there is a relatively large pool of Fe-and Al-bound P.The interactions between citric and malic acids at the above concentrations,and p added at rates of 10,20,40,and 80mg/kg were determined.At zero levels of organic acids,all added P became either labile or bound ,and greater proportions remained soluble as the concentration of orgaic acids increased,which suggested that organic acids reduced fixation of dissolved P in Fe-and AL-rich soils .Agricultural practices which increase organic matter input on P-deficient acid soild could decrease P deficiency,This would be important in many tropical and subtropical regions where these soils are common,and where the costs of fertilizers and lime are relatively high.

  2. Antimicrobial and cytotoxic effects of phosphoric acid solution compared to other root canal irrigants

    Directory of Open Access Journals (Sweden)

    Maíra PRADO

    2015-04-01

    Full Text Available Phosphoric acid has been suggested as an irrigant due to its effectiveness in removing the smear layer. Objectives : The purpose of this study was to compare the antimicrobial and cytotoxic effects of a 37% phosphoric acid solution to other irrigants commonly used in endodontics. Material and Methods : The substances 37% phosphoric acid, 17% EDTA, 10% citric acid, 2% chlorhexidine (solution and gel, and 5.25% NaOCl were evaluated. The antimicrobial activity was tested against Candida albicans, Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Actinomyces meyeri, Parvimonas micra, Porphyromonas gingivalis, and Prevotella nigrescens according to the agar diffusion method. The cytotoxicity of the irrigants was determined by using the MTT assay. Results : Phosphoric acid presented higher antimicrobial activity compared to the other tested irrigants. With regard to the cell viability, this solution showed results similar to those with 5.25% NaOCl and 2% chlorhexidine (gel and solution, whereas 17% EDTA and 10% citric acid showed higher cell viability compared to other irrigants. Conclusion : Phosphoric acid demonstrated higher antimicrobial activity and cytotoxicity similar to that of 5.25% NaOCl and 2% chlorhexidine (gel and solution.

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Hyejeong [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Chonbuk, Jeongeup 580-185 (Korea, Republic of); Department of Food Science and Technology, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Lim, Sangyong [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Chonbuk, Jeongeup 580-185 (Korea, Republic of); Jo, Cheorun [Department of Animal Science and Biotechnology, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Chung, Jinwoo [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Chonbuk, Jeongeup 580-185 (Korea, Republic of); Kim, Soohyun [Glycomics Team, Korea Basic Science Institute, Daejeon 305-333 (Korea, Republic of); Kwon, Joong-Ho [Department of Food Science and Technology, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Kim, Dongho [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Chonbuk, Jeongeup 580-185 (Korea, Republic of)], E-mail: fungikim@kaeri.re.kr

    2008-06-15

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

  5. Evaluation of the Efficacy, Safety, and Tolerability of 3 Dose Regimens of Topical Sodium Nitrite With Citric Acid in Patients With Anogenital Warts A Randomized Clinical Trial

    NARCIS (Netherlands)

    Ormerod, Anthony D.; van Voorst Vader, Pieter C.; Majewski, Slovomir; Vanscheidt, Wolfgang; Benjamin, Nigel; van der Meijden, Willem

    2015-01-01

    IMPORTANCE Anogenital warts are a common disorder associated with significant physical and mental distress and a substantial cause of health care costs. OBJECTIVE To assess the efficacy of the topical application of nitric oxide delivered using acidified nitrite. DESIGN, SETTING, AND PARTICIPANTS A

  6. Ghrelin Is Produced in Taste Cells and Ghrelin Receptor Null Mice Show Reduced Taste Responsivity to Salty (NaCl) and Sour (Citric Acid) Tastants

    OpenAIRE

    Yu-Kyong Shin; Bronwen Martin; Wook Kim; White, Caitlin M.; Sunggoan Ji; Yuxiang Sun; Smith, Roy G.; Jean Sévigny; Tschöp, Matthias H.; Stuart Maudsley; Egan, Josephine M.

    2010-01-01

    BACKGROUND: The gustatory system plays a critical role in determining food preferences, food intake and energy balance. The exact mechanisms that fine tune taste sensitivity are currently poorly defined, but it is clear that numerous factors such as efferent input and specific signal transduction cascades are involved. METHODOLOGY/PRINCIPAL FINDINGS: Using immunohistochemical analyses, we show that ghrelin, a hormone classically considered to be an appetite-regulating hormone, is present with...

  7. The production and use of citric acid for the removal of potassium from the iron ore concentrate of the Sishen Iron Ore Mine, South Africa

    OpenAIRE

    Peter J. Williams; Thomas E. Cloete

    2010-01-01

    The depletion of the richer iron ore worldwide has made it necessary to process lower quality iron ore. Certain substances, such as potassium, contained within the lower quality iron ore, have a detrimental effect on the smelting process during steel manufacturing. Therefore, international steel-making companies charge penalties when purchasing iron ore concentrates containing high concentrations of potassium. To date, lower quality iron ore has been blended with high quality iron ore in an a...

  8. Disinfection of foot-and-mouth disease and African swine fever viruses with citric acid and sodium hypochlorite on birch wood carriers

    Science.gov (United States)

    Transboundary animal disease viruses such as foot-and-mouth disease virus (FMDV) and African swine fever virus (ASFV) are highly contagious and cause severe morbidity and mortality in livestock. Proper disinfection during an outbreak can help prevent virus spread and will shorten the time for contam...

  9. The intrinsic antimicrobial activity of citric acid-coated manganese ferrite nanoparticles is enhanced after conjugation with the antifungal peptide Cm-p5

    OpenAIRE

    Franco, Octavio; Lopez-Abarrategui, Carlos; Figueroa-Espi,Viviana; Lugo-Alvarez,Maria; Pereira,Caroline; Garay, Hilda; Barbosa, Joao; Jimenez-Hernandez,Linnavel; Estevez-Hernandez, Osvaldo; Reguera-Ruiz,Edilso; Dias,Simoni; Otero-Gonzalez,Anselmo; Falcao,Rosana

    2016-01-01

    Carlos Lopez-Abarrategui,1 Viviana Figueroa-Espi,2 Maria B Lugo-Alvarez,1 Caroline D Pereira,3 Hilda Garay,4 João ARG Barbosa,5 Rosana Falcão,6 Linnavel Jiménez-Hernández,2 Osvaldo Estévez-Hernández,2,7 Edilso Reguera,8 Octavio L Franco,3,9 Simoni C Dias,3 Anselmo J Otero-Gonzalez1 1Faculty of Biology, Center for Protein Studies, 2Lab of Structural Analysis, Institute of Materials Science and Technol...

  10. General situation and prospect of citric acid production worldwide%世界柠檬酸生产概况及前景展望

    Institute of Scientific and Technical Information of China (English)

    于春梅; 满俊

    2000-01-01

    1999年世界柠檬酸生产能力87.9万t,消费量约70万t.全球消费年增长率4%~5%,美国为3%,欧洲为2.5%,发展中国家为5%~10%.预计2005年,世界消费量达90万t以上,我国柠檬酸消费量约10万t.

  11. A citric acid solution is an optimal test drink in the 13C-urea breath test for the diagnosis of Helicobacter pylori infection.

    OpenAIRE

    J. E. Domínguez-Muñoz; Leodolter, A; Sauerbruch, T; Malfertheiner, P

    1997-01-01

    BACKGROUND: The 13C-urea breath test (13C-UBT) is a simple, non-invasive and reliable test for the diagnosis of Helicobacter pylori infection. The duration of the test, the timing of breath sampling, and the accuracy of the method vary according to the test meal used. AIM: To identify the optimal test meal or drink for rapid and accurate performance of the 13C-UBT for the detection of H pylori infection. PATIENTS: Eighty patients with dyspeptic symptoms were included. Of these, 48 patients ha...

  12. Tamibarotene-loaded citric acid-crosslinked alkali-treated collagen matrix as a coating material for a drug-eluting stent

    Directory of Open Access Journals (Sweden)

    Motoki Inoue, Mariko Takayanagi, Katsuhito Fujiu, Ichiro Manabe, Ryozo Nagai and Tetsushi Taguchi

    2012-01-01

    Full Text Available Tamibarotene-loaded biodegradable matrices with antithrombogenic and drug-releasing properties were prepared in a crosslinking reaction between amino groups of alkali-treated collagen (AlCol and active ester groups of trisuccinimidyl citrate. The resulting matrices were characterized by their residual amino group concentrations, swelling ratios and thermal, antithrombogenic and drug-releasing properties. It was clarified that the addition of tamibarotene does not inhibit matrix formation. After immersion in water, the swelling ratio of a matrix became lower than that prior to immersion. Thermal analysis indicated that AlCol interacted with tamibarotene. The addition of tamibarotene to the matrix did not influence the antithrombogenic property of the resulting matrix. A matrix with a high crosslinking density had a prolonged tamibarotene elution time. These results demonstrate that tamibarotene-loaded matrices have great potential as a coating material for drug-eluting stents.

  13. Organic acids inhibit the formation of pyromorphite and Zn-phosphate in phosphorous amended Pb- and Zn-contaminated soil.

    Science.gov (United States)

    Debela, F; Arocena, J M; Thring, R W; Whitcombe, T

    2013-02-15

    Pyromorphite (PY) and some zinc phosphates (Zn-P) are very sparingly soluble minerals and hence can immobilize Pb and Zn in contaminated soils. However, mechanisms leading to the poor efficiency of PY and Zn-P formation in contaminated soils amended with P still remain unclear. We studied the influence of two low molecular weight organic acids (LMWOA) - oxalic acid and citric acid and diethylene triamine pentaacetic acid (DTPA) - in PY and Zn-P formation in a P-amended contaminated soil. Despite the high levels of metals (∼4% Pb and 21% Zn) in the study soil, the addition of up to 1% inorganic P transformed only up to 37% and 17% of the total Pb and Zn to PY and Zn-P, respectively. Semi-quantitative estimates from a linear combination fitting of X-ray absorption near edge spectra (LC-XANES fitting) showed that the formation of PY decreased from 37% to 3% of the total Pb in the presence of oxalic acid and the addition of 1% P. The reduced PY formation may be associated with the increase in organic-bound Pb from 9% to 54% and decrease in carbonate associated Pb from 42% to 12% with oxalic acid addition as indicated by a chemical sequential extraction (SE) technique. Citric acid seemed to have a less adverse effect in PY formation than oxalic acid. Our data also suggests both oxalic and citric acids have less adverse effects on the efficiency of Zn-P formation. From this study we conclude that the abundance of LMWOA in soil environments can be one factor contributing to the poor efficiency of P amendments practices to effectively immobilize Pb and Zn in metal contaminated soils. PMID:23313859

  14. Reduction of off-flavour compounds (geosmin and 2-methylisoborneol using different organic acids

    Directory of Open Access Journals (Sweden)

    Jade G. Pahila

    2013-11-01

    Full Text Available A study on the reduction of off-flavour compounds that cause “earthy” and “musty” organoleptic sensorial characteristic in fresh water systems was conducted. These compounds include geosmin and 2-methylisoborneol (MIB, which are produced as metabolites by some algal and bacterial species. Drinking water and aquaculture commodities affected by these compounds become undesirable to consumers, and market values tend to drop significantly. Triple distilled water samples spiked with approximately 1 µg Kg-1 geosmin and 1 µg Kg-1 2-methylisoborneol were dehydrated through acidification using two different food grade organic acids (acetic and citric acid, at different concentrations: 0.1, 1.0 and 4.0% (w/w. Levels of geosmin and MIB reduction were determined using Solid Phase Microextraction (SPME and Gas Chromatographic/Mass Spectroscopic (GCMS analyses. Results showed that acidification treatments of the off-flavour compounds using varying concentrations of acetic and citric acids significantly reduced the concentrations of geosmin and MIB in the samples. Treatments with 1.0% citric acid and 4.0% acetic acid significantly reduced the concentration of geosmin to concentrations as low as 0.07±0.03 and 0.09±0.01 µg Kg-1 respectively, while the reduction of MIB to concentrations of around 0.05±0.01 µg Kg-1 was achieved at a minimum concentration of 0.1% of either acid used. Previous studies reported that products of the dehydration process of geosmin and MIB produce non-odourous products such as argosmin, and 2-methylenebornane and 1-methylcamphene respectively.

  15. Influence of chitosan coatings with citric essential oil on the shelf-life of minimally processed mango (Mangifera indica L.

    Directory of Open Access Journals (Sweden)

    Fabián Rico Rodríguez

    2015-06-01

    Full Text Available Demand for minimally processed fruits have increaseddue to their nutritional value and an increasing change inconsumption habits. Physicochemical, microbiological, structuraland sensory changes were determined in minimally processedmangoes (MPM with chitosan (CH edible coatings and lemonand orange essential oils (EOL. The MPM was first dipped in citricacid and a texturizing solution and then dipped in CH and lemonor orange EOL coatings. Weight loss, sensory acceptance, totalsoluble solids, total acidity, ascorbic acid, color changes, firmnessand elasticity, and microbiological changes were quantified for11 days of refrigerated storage. The CH and lemon EOL coatinghad more acceptance than the other treatments. No differenceswere found (p>0.05 for weight loss, total acidity, ascorbic acid,firmness or elasticity. There was a high amount of total phenolsdue to the EOL composition, as well as a high antioxidant capacityin the early days of storage. This characteristic decreased in thefinal days of the study. There was a decrease in the microbialcharge for the lemon EOL treatment, as compared to the othersamples. The CH and lemon EOL coating helped to maintain theshelf-life of the MPM for 11 days of storage without affecting thesensory acceptance. The CH and Orange EOL coating did nothave an effect on the MPM physicochemical attributes; however,the sensory acceptance was negatively affected with off-flavorsconferred to the MPM.

  16. Interactions between hydrated cement paste and organic acids: Thermodynamic data and speciation modeling

    International Nuclear Information System (INIS)

    Interactions of short-chain organic acids with hydrated cement phases affect structure durability in the agro-food and nuclear waste industries but can also be used to modify cement properties. Most previous studies have been experimental, performed at fixed concentrations and pH, without quantitatively discriminating among polyacidity effects, or complexation and salt precipitation processes. This paper addresses such issues by thermodynamic equilibrium calculations for acetic, citric, oxalic, succinic acids and a simplified hydrated CEM-I. The thermodynamic constants collected from the literature allow the speciation to be modeled over a wide range of pH and concentrations. Citric and oxalic had a stronger chelating effect than acetic acid, while succinic acid was intermediate. Similarly, Ca-citrate and Ca-oxalate salts were more insoluble than Ca-acetate and Ca-succinate salts. Regarding aluminium complexation, hydroxyls, sulfates, and acid competition was highlighted. The exploration of acid mixtures showed the preponderant effect of oxalate and citrate over acetate and succinate

  17. Vapor pressures of substituted polycarboxylic acids are much lower than previously reported

    Directory of Open Access Journals (Sweden)

    A. J. Huisman

    2013-07-01

    Full Text Available The partitioning of compounds between the aerosol and gas phase is a primary focus in the study of the formation and fate of secondary organic aerosol. We present measurements of the vapor pressure of 2-methylmalonic (isosuccinic acid, 2-hydroxymalonic (tartronic acid, 2-methylglutaric acid, 3-hydroxy-3-carboxy-glutaric (citric acid and DL-2,3-dihydroxysuccinic (DL-tartaric acid, which were obtained from the evaporation rate of supersaturated liquid particles levitated in an electrodynamic balance. Our measurements indicate that the pure component liquid vapor pressures at 298.15 K for tartronic, citric and tartaric acids are much lower than the same quantity that was derived from solid state measurements in the only other room temperature measurement of these materials (made by Booth et al., 2010. This strongly suggests that empirical correction terms in a recent vapor pressure estimation model to account for the inexplicably high vapor pressures of these and similar compounds should be revisited, and that due caution should be used when the estimated vapor pressures of these and similar compounds are used as inputs for other studies.

  18. Study of the organic acids composition of quince (Cydonia oblonga Miller) fruit and jam.

    Science.gov (United States)

    Silva, Branca M; Andrade, Paula B; Mendes, Gisela C; Seabra, Rosa M; Ferreira, Margarida A

    2002-04-10

    The organic acids present in several samples of quince fruit (pulp and peel) and quince jam (homemade and industrially manufactured) were analyzed by HPLC. The sample preparation was simple, involving only extraction with methanol (40 degrees C) and filtration through a Sep-pack C18 cartridge. The chromatographic separation was achieved using an ion exclusion column, Nucleogel Ion 300 OA (300 x 7.7 mm), in conjunction with a column heating device at 30 degrees C. An isocratic elution with H(2)SO(4) 0.01 N as the mobile phase, with a flow rate of 0.1 mL/min, and UV detection at 214 nm were used. These analyses showed that all samples presented a similar profile composed of at least six identified organic acids: citric, ascorbic, malic, quinic, shikimic, and fumaric acids. Several samples also contained oxalic acid. This study suggests that the organic acids levels and ratios may be useful for the determination of percent fruit content of quince jams. The citric acid value can also be used in the differentiation of the type of manufacture of the commercial quince jams (homemade or industrially manufactured). PMID:11929290

  19. Changes of organic acid exudation and rhizosphere pH in rice plants under chromium stress

    International Nuclear Information System (INIS)

    The effect of chromium (Cr) stress on the changes of rhizosphere pH, organic acid exudation, and Cr accumulation in plants was studied using two rice genotypes differing in grain Cr accumulation. The results showed that rhizosphere pH increased with increasing level of Cr in the culture solution and with an extended time of Cr exposure. Among the six organic acids examined in this experiment, oxalic and malic acid contents were relatively higher, and had a significant positive correlation with the rhizosphere pH, indicating that they play an important role in changing rhizosphere pH. The Cr content in roots was significantly higher than that in stems and leaves. Cr accumulation in plants was significantly and positively correlated with rhizosphere pH, and the exudation of oxalic, malic and citric acids, suggesting that an increase in rhizosphere pH, and exudation of oxalic, malic and citric acid enhances Cr accumulation in rice plants. - Rhizosphere pH and organic acid exudation of rice roots are markedly affected by chromium level in culture solution

  20. Quantification of organic acids in beer by nuclear magnetic resonance (NMR)-based methods

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, J.E.A. [CICECO-Department of Chemistry, University of Aveiro, Campus de Santiago, 3810-193 Aveiro (Portugal); Erny, G.L. [CESAM - Department of Chemistry, University of Aveiro, Campus de Santiago, 3810-193 Aveiro (Portugal); Barros, A.S. [QOPNAA-Department of Chemistry, University of Aveiro, Campus de Santiago, 3810-193 Aveiro (Portugal); Esteves, V.I. [CESAM - Department of Chemistry, University of Aveiro, Campus de Santiago, 3810-193 Aveiro (Portugal); Brandao, T.; Ferreira, A.A. [UNICER, Bebidas de Portugal, Leca do Balio, 4466-955 S. Mamede de Infesta (Portugal); Cabrita, E. [Department of Chemistry, New University of Lisbon, 2825-114 Caparica (Portugal); Gil, A.M., E-mail: agil@ua.pt [CICECO-Department of Chemistry, University of Aveiro, Campus de Santiago, 3810-193 Aveiro (Portugal)

    2010-08-03

    The organic acids present in beer provide important information on the product's quality and history, determining organoleptic properties and being useful indicators of fermentation performance. NMR spectroscopy may be used for rapid quantification of organic acids in beer and different NMR-based methodologies are hereby compared for the six main acids found in beer (acetic, citric, lactic, malic, pyruvic and succinic). The use of partial least squares (PLS) regression enables faster quantification, compared to traditional integration methods, and the performance of PLS models built using different reference methods (capillary electrophoresis (CE), both with direct and indirect UV detection, and enzymatic essays) was investigated. The best multivariate models were obtained using CE/indirect detection and enzymatic essays as reference and their response was compared with NMR integration, either using an internal reference or an electrical reference signal (Electronic REference To access In vivo Concentrations, ERETIC). NMR integration results generally agree with those obtained by PLS, with some overestimation for malic and pyruvic acids, probably due to peak overlap and subsequent integral errors, and an apparent relative underestimation for citric acid. Overall, these results make the PLS-NMR method an interesting choice for organic acid quantification in beer.

  1. Interactions between hydrated cement paste and organic acids: Thermodynamic data and speciation modeling

    Energy Technology Data Exchange (ETDEWEB)

    De Windt, Laurent, E-mail: laurent.dewindt@mines-paristech.fr [MINES ParisTech, PSL Research University, Centre de Géosciences, 35 Rue St-Honoré, 77305 Fontainebleau Cedex (France); Bertron, Alexandra; Larreur-Cayol, Steeves; Escadeillas, Gilles [University of Toulouse, UPS/INSA/LMDC, 135 Av. de Rangueil, 31077 Toulouse Cedex 04 (France)

    2015-03-15

    Interactions of short-chain organic acids with hydrated cement phases affect structure durability in the agro-food and nuclear waste industries but can also be used to modify cement properties. Most previous studies have been experimental, performed at fixed concentrations and pH, without quantitatively discriminating among polyacidity effects, or complexation and salt precipitation processes. This paper addresses such issues by thermodynamic equilibrium calculations for acetic, citric, oxalic, succinic acids and a simplified hydrated CEM-I. The thermodynamic constants collected from the literature allow the speciation to be modeled over a wide range of pH and concentrations. Citric and oxalic had a stronger chelating effect than acetic acid, while succinic acid was intermediate. Similarly, Ca-citrate and Ca-oxalate salts were more insoluble than Ca-acetate and Ca-succinate salts. Regarding aluminium complexation, hydroxyls, sulfates, and acid competition was highlighted. The exploration of acid mixtures showed the preponderant effect of oxalate and citrate over acetate and succinate.

  2. Quantification of organic acids in beer by nuclear magnetic resonance (NMR)-based methods

    International Nuclear Information System (INIS)

    The organic acids present in beer provide important information on the product's quality and history, determining organoleptic properties and being useful indicators of fermentation performance. NMR spectroscopy may be used for rapid quantification of organic acids in beer and different NMR-based methodologies are hereby compared for the six main acids found in beer (acetic, citric, lactic, malic, pyruvic and succinic). The use of partial least squares (PLS) regression enables faster quantification, compared to traditional integration methods, and the performance of PLS models built using different reference methods (capillary electrophoresis (CE), both with direct and indirect UV detection, and enzymatic essays) was investigated. The best multivariate models were obtained using CE/indirect detection and enzymatic essays as reference and their response was compared with NMR integration, either using an internal reference or an electrical reference signal (Electronic REference To access In vivo Concentrations, ERETIC). NMR integration results generally agree with those obtained by PLS, with some overestimation for malic and pyruvic acids, probably due to peak overlap and subsequent integral errors, and an apparent relative underestimation for citric acid. Overall, these results make the PLS-NMR method an interesting choice for organic acid quantification in beer.

  3. The Research of Acid Analysis and Acid Reduction Technology in Kiwi Wine%猕猴桃酒中酸份分析及其降酸工艺研究

    Institute of Scientific and Technical Information of China (English)

    何宏魁; 李红歌; 李晓欢; 梁绍勋; 刘国英; 汤有宏

    2015-01-01

    采用高效液相色谱法确定了猕猴桃酒中的酸份组成,猕猴桃酒中有机酸主要为苹果酸、酒石酸、柠檬酸,并分析苹果酸、酒石酸、柠檬酸所占浓度,寻找最佳降酸剂的比例,通过单因素实验和正交试验得出最佳降酸工艺条件为碳酸钠1.2g/L、碳酸钾0.4g/L、酒石酸钾3g/L.%The acid formed in kiwifruit wine was determinated by high performance liquid chromatography (HPLC), and the main organic acids in the wine were malic acid, tartaric acid, citric acid. We analysed the content of malic acid, tartaric acid, citric acid and found the best proportion of deacidification agent. Based on the single factor experiment and orthogonal experiment method, we obtained the optimum deacidification conditions which were 1.2 g/L Na2CO3, 0.4g/L K2CO3, 3g/L C4H6K2O7.

  4. Dissolution kinetics of nickel ferrite in amino poly carboxylic acids

    International Nuclear Information System (INIS)

    Nickel ferrite is one of the important corrosion products of PHWR's where Monel and carbon steel are used as the constructional materials in the primary heat transport system. The dissolution of synthetically prepared nickel ferrite was studied in low concentrations (< 10 mmol/l) of HEDTA, DTPA, NTA and HIDA. The dependence of the dissolution rate on the ligand concentration was found to be langmuirian in all these cases. The effect of the addition of low concentrations of citric acid, oxalic acid, ascorbic acid and Fe(II)-ligand complex, individually, to each of the above chelating agents was also studied. The effect of pH and temperature on the dissolution rate was determined. (author)

  5. Phosphorus release from phosphate rock and iron phosphate by low-molecular-weight organic acids

    Institute of Scientific and Technical Information of China (English)

    XU Ren-kou; ZHU Yong-guan; David Chittleborough

    2004-01-01

    Low-molecular-weight(LMW) organic acids widely exist in soils, particularly in the rhizosphere. A series of batch experiments were carried out to investigate the phosphorus release from rock phosphate and iron phosphate by Iow-molecular-weight organic acids.Results showed that citric acid had the highest capacity to solubilize P from both rock and iron phosphate. P solubilization from rock phosphate and iron phosphate resulted in net proton consumption. P release from rock phosphate was positively correlated with the pKa values. P release from iron phosphate was positively correlated with Fe-organic acid stability constants except for aromatic acids, but was not correlated with PKa. Increase in the concentrations of organic acids enhanced P solubilization from both rock and iron phosphate almost linearrly. Addition of phenolic compounds further increased the P release from iron phosphate. Initial solution pH had much more substantial effect on P release from rock phosphate than from iron phosphate.

  6. Determination of Vitamin C and Organic Acid Changes in Strawberry by HPLC During Cold Storage

    Directory of Open Access Journals (Sweden)

    Mehmet Ali KOYUNCU

    2010-12-01

    Full Text Available High pressure liquid chromatographic (HPLC methods were used for measurement of vitamin C and organic acid changes of two strawberry cultivars (‘Dorit’ and ‘Selva’ during cold storage. Harvested strawberries at the last stage of commercial ripeness were placed in perforated (8 perforations, 10 mm diameter plastic boxes and stored at 0°C temperature and 90-95% relative humidity for 10 days. Vitamin C content decreased in both cultivars but no significant differences were found in ‘Dorit’ from the beginning to the end of the storage. The highest share of total acids was contributed by citric acid. It decreased with increase in storage time in both cultivars. Malic acid content of cultivars also decreased with storage time. Tartaric, oxalic and fumaric acid contents fluctuated during storage, but at the end of cold storage these organic acids had decreased in comparison to initial values.

  7. Slight Fermentation with Lactobacillus fermentium Improves the Taste (Sugar:Acid Ratio) of Citrus (Citrus reticulata cv. chachiensis) Juice.

    Science.gov (United States)

    Yu, Yuanshan; Xiao, Gengsheng; Xu, Yujuan; Wu, Jijun; Fu, Manqin; Wen, Jing

    2015-11-01

    The aim of this study was to evaluate the hypothesis that fermentation with Lactobacillus fermentium, which can metabolize citric acid, could be applied in improving the taste (sugar:acid ratio) of citrus juice. During fermentation, the strain of L. fermentium can preferentially utilize citric acid of citrus (Citrus reticulata cv. Chachiensis) juice to support the growth without the consumption of sugar. After 6 h of fermentation with L. fermentium at 30 °C, the sugar:acid ratio of citrus juice increased to 22:1 from 12:1, which resulted in that the hedonic scores of sweetness, acidity and overall acceptability of fermented-pasteurized citrus juice were higher than the unfermented-pasteurized citrus juice. Compared with unfermented-pasteurized citrus juice, the ORAC value and total amino acid showed a reduction, and no significant change (P > 0.05) in the L*, a*, b*, total soluble phenolics and ascorbic acid (Vc) content in the fermented-pasteurized citrus juice was observed as compared with unfermented-pasteurized citrus juice. Hence, slight fermentation with L. fermentium can be used for improving the taste (sugar:acid ratio) of citrus juice with the well retaining of quality. PMID:26447635

  8. Metabolic engineering of Yarrowia lipolytica for itaconic acid production.

    Science.gov (United States)

    Blazeck, John; Hill, Andrew; Jamoussi, Mariam; Pan, Anny; Miller, Jarrett; Alper, Hal S

    2015-11-01

    Itaconic acid is a naturally produced organic acid with diverse applications as a replacement for petroleum derived products. However, its industrial viability as a bio-replacement has been restricted due to limitations with native producers. In this light, Yarrowia lipolytica is an excellent potential candidate for itaconic acid production due to its innate capacity to accumulate citric acid cycle intermediates and tolerance to lower pH. Here, we demonstrate the capacity to produce itaconic acid in Y. lipolytica through heterologous expression of the itaconic acid synthesis enzyme, resulting in an initial titer of 33 mg/L. Further optimizations of this strain via metabolic pathway engineering, enzyme localization, and media optimization strategies enabled 4.6g/L of itaconic acid to be produced in bioreactors, representing a 140-fold improvement over initial titer. Moreover, these fermentation conditions did not require additional nutrient supplementation and utilized a low pH condition that enabled the acid form of itaconic acid to be produced. Overall yields (0.058 g/g yield from glucose) and maximum productivity of 0.045 g/L/h still provide areas for future strain improvement. Nevertheless, this work demonstrates that Y. lipolytica has the potential to serve as an industrially relevant platform for itaconic acid production. PMID:26384571

  9. The influence of stress conditions on the growth of selected lactic acid bacteria

    International Nuclear Information System (INIS)

    A study was undertaken to determine the effects of certain stress conditions on selected lactic acid bacteria. Where recontamination occurred, lactic acid bacteria was already the dominant bacterial group, with counts of higher than 106/g in vacuum-packaged 'shelf stable' meat products after 1 week storage at 25 and 37 degrees Celsius respectively. Some of the isolates were capable of growing at a pH of 3,9. The minimum pH for growth of a specific culture was dependant on the type of acid that was used to lower the pH. Lactic and acetic acid had the highest inhibitory action. Hydrochloric and citric acid showed similar inhibitory effects, while the effects when using ascorbic acid or gluconic acid for lowering the pH were also fairly similar. Increase in the activity of certain lactic acid bacteria was noticed where the ratio of undissociated to dissociated citric acid in the medium was increased. After exceeding a concentration of 0,048 moles/l undissosiated citric acid in the medium, the activity of the majority of cultures was progressively inhibited. This phenomenon was also found with acetic acid for certain cultures. Selected lactic acid bacteria were resistant to an water activity (a (sub w)) of 0,94 in MRS broth, where NaCl or glycerol was used as a humectant. The minimum a (sub w) for growth was dependent on the type of humectant used. Concentrations of sodium benzoate and potassium sorbate were necessary to inhibit the majority of strains. The % inhibition by sodium benzoate and methyl paraben did not significantly change with a lowering in the pH of the growth medium. Except in the case of lactic acid, the different acids used to lower the pH of the medium did not have a significant effect on the % inhibition by the chemical preservatives. For the cocci, gamma D10 values of between 0,82 and 1,29 kGy were recorded, whereas the lactobacilli were less resistant to gamma rays, with D10 values of between 0,21 and 0,54 kGy

  10. 低分子有机酸对土壤中Pb形态的影响%Effects of Low Molecular Weight Organic Acids on Speciation of Pb in Soil

    Institute of Scientific and Technical Information of China (English)

    钱翌; 刘莹; 彭晓丽

    2011-01-01

    To investigate the mechanism of chelate-induced phytoremediation,effects of two kinds of low molecular weight organic acids including citric acid and malic acid on chemical speciation of Pb in soil were studied.Results showed that,for different pollution levels of soil(PbⅠ-PbⅣ),percentage of the most active exchangeable Pb increased significantly as concentration of organic acids were increased.So as to achieve the objective of activating Pb;The mobilization effect of Pb would increase along with concentration of citric acid,and with higher concentration of malic acid added,the mobilization effect of Pb first increased then kept on,when malic acid concentration was 10 mmol/kg and citric acid concentration was 20 mmol/kg,activation ability of malic acid and citric acid respectively reached the maximum value.By comparison,activation ability of citric acid was better than malic acid.%为探讨螯合诱导修复技术的作用机制,研究2种低分子有机酸即柠檬酸和苹果酸对土壤中重金属Pb各形态的影响。结果表明,对于人工模拟不同污染程度的PbⅠ~PbⅣ土壤,随着柠檬酸和苹果酸添加浓度的升高,土壤中最具活性的可交换态Pb百分含量均有不同程度的提高,从而达到了活化重金属Pb的目的;Pb活化效果随柠檬酸浓度升高而升高,随苹果酸浓度升高呈先上升后基本不变趋势,当有机酸浓度为10,20 mmol/kg时,苹果酸和柠檬酸活化Pb效果分别达到最优;二者相比,柠檬酸活化Pb效果优于苹果酸的活化效果。

  11. Effects of intermediate metabolite carboxylic acids of TCA cycle on Microcystis with overproduction of phycocyanin.

    Science.gov (United States)

    Bai, Shijie; Dai, Jingcheng; Xia, Ming; Ruan, Jing; Wei, Hehong; Yu, Dianzhen; Li, Ronghui; Jing, Hongmei; Tian, Chunyuan; Song, Lirong; Qiu, Dongru

    2015-04-01

    Toxic Microcystis species are the main bloom-forming cyanobacteria in freshwaters. It is imperative to develop efficient techniques to control these notorious harmful algal blooms (HABs). Here, we present a simple, efficient, and environmentally safe algicidal way to control Microcystis blooms, by using intermediate carboxylic acids from the tricarboxylic acid (TCA) cycle. The citric acid, alpha-ketoglutaric acid, succinic acid, fumaric acid, and malic acid all exhibited strong algicidal effects, and particularly succinic acid could cause the rapid lysis of Microcystis in a few hours. It is revealed that the Microcystis-lysing activity of succinic acid and other carboxylic acids was due to their strong acidic activity. Interestingly, the acid-lysed Microcystis cells released large amounts of phycocyanin, about 27-fold higher than those of the control. On the other hand, the transcription of mcyA and mcyD of the microcystin biosynthesis operon was not upregulated by addition of alpha-ketoglutaric acid and other carboxylic acids. Consider the environmental safety of intermediate carboxylic acids. We propose that administration of TCA cycle organic acids may not only provide an algicidal method with high efficiency and environmental safety but also serve as an applicable way to produce and extract phycocyanin from cyanobacterial biomass. PMID:25342454

  12. Effect of a Previous Acid Adaptation of Zygosaccharomyces bailii on its Growth Kinetic in Acidic Media

    Directory of Open Access Journals (Sweden)

    Alex Tchuenchieu

    2014-11-01

    Full Text Available The growth response of Zygosaccharomyces bailii acid adapted cells was assessed in acidified media. Yeast cells were first pre-cultured in nutrient broth adjusted with hydrochloric, citric and malic acid to pH 4; 4.5; 5; 5.5; 6 and 6.5. Moreover, they were also grown in two controls consisting of nutrient broth and nutrient broth supplemented with 1% of glucose both adjusted at pH 7. The variation of pH before and after the growth along with yeast concentration was measured. The cells pre-cultured in controls conditions and in the three conditions at pH 5 were then each inoculated in six BHI medium consisting of BHI adjusted with hydrochloric, citric and malic acid at pH 5.5 and 3.5. The growth was monitored by spectrophotometry and the yeast concentration after incubation was obtained by microscopy using a Thoma cell chamber. DMFit 2.1 was used to plot the growth curves and to estimate the growth parameters. All the pre-cultures and cultures were made at 37°C during 24 hours. During the pre-cultures, an important decrease of pH was noted in nutrient broth supplemented with glucose, moving from 7 to 3.81. In all the other pre-cultures, just a little variation was observed ranging from -0.57 to 0.50. Growth was observed in all the conditions, except at pH4. By growing the cells coming from the selected pre-cultures conditions in the different acidic BHI media, it appears that acid adaptation enhance the growth at pH 5.5 no matter the acid contains in the medium and the acid to which the cells were adapted. However, this acid adaptation was not sufficient to initiate growth at pH 3.5 after 24 hours of incubation at 37°C. Growth rate was significantly affected by the pH of the pre-culture medium and the acid present in the culture medium. Pre-culture with glucose supplementation was the only parameter studied affecting the latency.

  13. Phragmites australis response to Cu in terms of low molecular weight organic acids (LMWOAs) exudation: Influence of the physiological cycle

    Science.gov (United States)

    Rocha, A. Cristina S.; Almeida, C. Marisa R.; Basto, M. Clara P.; Vasconcelos, M. Teresa S. D.

    2014-06-01

    Plant roots have the ability to produce and secrete substances, such as aliphatic low molecular weight organic acids (ALMWOAs), into the rhizosphere for several purposes, including in response to metal contamination. Despite this, little is yet known about the exudation of such substances from marsh plants roots in response to metal exposure. This work aimed at assessing the influence of the physiological cycle of marsh plants on the exudation of ALMWOAs in response to Cu contamination. In vitro experiments were carried out with Phragmites australis specimens, collected in different seasons. Plant roots were exposed to freshwater contaminated with two different Cu concentrations (67 μg/L and 6.9 mg/L), being the ALMWOAs released by the roots measured. Significant differences (both qualitative and quantitative) were observed during the Phragmites australis life cycle. At growing stage, Cu stimulated the exudation of oxalic and formic acids but no significant stimulation was observed for citric acid. At developing stage, exposure to Cu caused inhibition of oxalic acid exudation whereas citric acid liberation was stimulated but only in the media spiked with the lowest Cu concentration tested. At the decaying stage, no significant variation on oxalic acid was observed, whereas the citric and formic acids release increased as a consequence of the plant exposure to Cu. The physiological cycle of Phragmites australis, and probably also of other marsh plants, is therefore an important feature conditioning plants response to Cu contamination, in terms of ALMWOAs exudation. Hence this aspect should be considered when conducting studies on rhizodeposition involving marsh plants exposed to metals and in the event of using marsh plants for phytoremediation purposes in contaminated estuarine areas.

  14. Metabolic Response of Pakchoi Leaves to Amino Acid Nitrogen

    Institute of Scientific and Technical Information of China (English)

    WANG Xiao-li; YU Wen-juan; ZHOU Qian; HAN Rui-feng; HUANG Dan-feng

    2014-01-01

    Different nitrogen (N) forms may cause changes in the metabolic profiles of plants. However, few studies have been conducted on the effects of amino acid-N on plant metabolic proifles. The main objective of this study was to identify primary metabolites associated with amino acid-N (Gly, Gln and Ala) through metabolic proifle analysis using gas chromatography-mass spectrometry (GC-MS). Plants of pakchoi (Brassica campestris L. ssp. chinensis L.), Huawang and Wuyueman cultivars, were grown with different nitrogen forms (i.e., Gly, Gln, Ala, NO3--N, and N starvation) applied under sterile hydroponic conditions. The fresh weight and plant N accumulation of Huawang were greater than those of Wuyueman, which indicates that the former exhibited better N-use efficiency than the latter. The physiological performances of the applied N forms were generally in the order of NO3--N>Gln>Gly>Ala. The metabolic analysis of leaf polar extracts revealed 30 amino acid N-responsive metabolites in the two pakchoi cultivars, mainly consisting of sugars, amino acids, and organic acids. Changes in the carbon metabolism of pakchoi leaves under amino acid treatments occurred via the accumulation of fructose, glucose, xylose, and arabinose. Disruption of amino acid metabolism resulted in accumulation of endogenous Gly in Gly treatment, Pro in Ala treatment, and Asn in three amino acid (Gly, Gln and Ala) treatments. By contrast, the levels of endogenous Gln and Leu decreased. However, this reduction varied among cultivars and amino acid types. Amino acid-N supply also affected the citric acid cycle, namely, the second stage of respiration, where leaves in Gly, Gln and Ala treatments contained low levels of malic, citric and succinic acids compared with leaves in NO3--N treatments. No signiifcant difference in the metabolic responses was observed between the two cultivars which differed in their capability to use N. The response of primary metabolites in pakchoi leaves to amino acid-N supply

  15. RECOVERY OF CARBOXYLIC ACIDS FROM AQUEOUS SOLUTIONS BY LIQUID-LIQUID EXTRACTION WITH A TRIISOOCTYLAMINE DILUENT SYSTEM

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    G. Malmary

    2001-12-01

    Full Text Available Tertiary alkylamines in solution with organic diluents are attractive extractants for the recovery of carboxylic acids from dilute aqueous phases. The aim of this study was to investigate the mechanism for extraction of organic acids from water by a long-chain aliphatic tertiary amine. In order to attain this objective, we studied the liquid-liquid equilibria between the triisooctylamine + 1-octanol + n-heptane system as solvent and an aqueous solution of an individual carboxylic acid such as citric, lactic and malic acids. The experiments showed that the partition coefficient for a particular organic acid depends on the kind of solute, notably when the acid concentration in the aqueous phase is low. A mathematical model, where both chemical association and physical distribution are taken into consideration, is proposed. The model suggests that the various complexes obtained between amine and organic acids contribute to the distribution of the solute between the coexisting phases in equilibrium.

  16. The Thresholds of Nine Organic Acids in Control and Degassed Light Beer%未除气与除气淡爽型啤酒中9种有机酸的阈值

    Institute of Scientific and Technical Information of China (English)

    陈慧; 张彦青; 张菡; 童军茂

    2011-01-01

    采用ASTM679标准方法测定了未除气与除气淡爽型啤酒中乙酸、乳酸、柠檬酸、苹果酸、琥珀酸、富马酸、丙酮酸、酒石酸和草酸的个人和小组阈值。结果发现,在未除气啤酒中,9种有机酸的小组阈值大小顺序为苹果酸、富马酸、乳酸、柠檬酸、丙酮酸、琥珀酸、乙酸、草酸、酒石酸。其中品评员对苹果酸、琥珀酸、富马酸、草酸和柠檬酸的口感差异相对较小,而对酒石酸、乙酸、丙酮酸和乳酸的口感差异较大。在除气啤酒中,9种有机酸的小组阈值大小顺序为丙酮酸、乳酸、乙酸、富马酸、琥珀酸、苹果酸、酒石酸、草酸、柠檬酸。品评员对柠檬酸、苹果酸和乳%The individual and group thresholds of nine organic acids were measured in control and degassed beer using the ASTM method 679 protocol. The results show that the group threshold of malic acid in control beer had the highest value in the 9 organic acids, followed by fumaric acid, lactic acid, citric acid, pyruvic acid, succinic acid, acetic acid, oxalic acid and tartaric acid in rank. The panelists have relative small differences in taste of malic acid, succinic acid, fumaric acid, oxalic acid and citric acid in the control beer, and the great discrepancy in mouth -feel of tartaric acid, acetic acid, pyruvic acid and lactic acid. The group thresholds of nine organic acids in degassed beer followed by pyruvic acid, lactic acid, acetic acid, fumaric acid, succinic acid, malic acid, tartaric acid, oxalic acid and citric acid in rank. The panelists have relative small differences in taste of citric acid, malic acid and lactic acid, and the great discrepancy in mouth -feel of pyruvic acid, oxalic acid, tartaric acid, fumaric acid, succinic acid and acetic acid. Besides, we have found significant difference in the group thresholds of nine organic acids between degassed and control beers. Triprotic acid has more significant difference

  17. Bioavailable concentrations of germanium and rare earth elements in soil as affected by low molecular weight organic acids and root exudates

    Science.gov (United States)

    Wiche, Oliver; Székely, Balázs; Kummer, Nicolai-Alexeji; Heinemann, Ute; Tesch, Silke; Heilmeier, Hermann

    2014-05-01

    Availability of elements in soil to plant is generally dependent on the solubility and mobility of elements in soil solution which is controlled by soil, elemental properties and plant-soil interactions. Low molecular organic acids or other root exudates may increase mobility and availability of certain elements for plants as an effect of lowering pH in the rhizosphere and complexation. However, these processes take place in a larger volume in soil, therefore to understand their nature, it is also important to know in which layers of the soil what factors modify these processes. In this work the influence of citric acid and root exudates of white lupin (Lupinus albus L.) on bioavailable concentrations of germanium, lanthan, neodymium, gadolinium and erbium in soil solution and uptake in root and shoot of rape (Brassica napus L.), comfrey (Symphytum officinale L.), common millet (Panicum milliaceum L.) and oat (Avena sativa L.) was investigated. Two different pot experiments were conducted: (1) the mentioned plant species were treated with nutrient solutions containing various amount of citric acid; (2) white lupin was cultivated in mixed culture (0 % lupin, 33 % lupin) with oat (Avena sativa L.) and soil solution was obtained by plastic suction cups placed at various depths. As a result, addition of citric acid significantly increased germanium concentrations in plant tissue of comfrey and rape and increased translocation of germanium, lanthan, neodymium, gadolinium and erbium from root to shoot. The cultivation of white lupin in mixed culture with oat led to significantly higher concentrations of germanium and increasing concentrations of lanthan, neodymium, gadolinium and erbium in soil solution and aboveground plant tissue. In these pots concentrations of citric acid in soil solution were significantly higher than in the control. The results show, that low molecular organic acids exuded by plant roots are of great importance for the mobilization of germanium

  18. Amino acids

    Science.gov (United States)

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

  19. A novel sono-assisted acid pretreatment of chili post harvest residue for bioethanol production.

    Science.gov (United States)

    Sindhu, Raveendran; Binod, Parameswaran; Pandey, Ashok

    2016-08-01

    The objective of the present study was to develop a sono-assisted acid pretreatment strategy for the effective removal of lignin and hemicelluloses and to improve the sugar yield from chili post harvest residue. Operational parameters that affect the pretreatment efficiency were studied and optimized. Inhibitor analysis of the hydrolyzate revealed that major fermentation inhibitors like furfural, hydroxymethyl furfural and organic acids like citric acid, succinic acid and propionic acid were absent. Changes in structural properties of the biomass were studied in relation to the pretreatment process using scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier Transform Infrared (FTIR) analysis, and the changes in chemical composition was also monitored. The biomass pretreated with the optimized novel method yielded 0.465g/g of reducing sugars on enzymatic hydrolysis. Fermentation of the non-detoxified hydrolysate yielded 2.14% of bioethanol with a fermentation efficiency of 71.03%. PMID:26949055

  20. The Effect Acid Addition on Characteristic Effervescent Tablet of Tamarillo

    Directory of Open Access Journals (Sweden)

    Fidela Violalita

    2015-01-01

    Full Text Available The aim of study was to determine the percentage of acid and its influence on characteristic effervescent tablet of tamarillo. The percentages of  acid addition that consist with citric acid and tartaric acid (1:1 were 15%, 20%, 25%, 30% and 35%. Water content, pH solution, vitamin C content, soluble duration, friability of tablet and organoleptic test on colour, aroma and flavour of tamarillo effervescent tablet were determined after addition of acid. The results showed that the difference in percentage of acid addition significantly affected to the water content, pH solution, soluble duration and friability of tablets. Based on organoleptic test, the tablet consist of 25% addition of acid was the best percentage of acid addition. The quality parameters in this percentage were the water content 6.09%, pH solution 4.80,  vitamin C 498.0800 mg/tablet, soluble duration 3.96 minute, friability of tablet 0.11%, while the averages of organoleptic test for colour were 3.40 (ordinary, aroma 3.36 (ordinary, and flavour 3.76 (like.