Bioleaching of a High Iron Content Kaolin by Aspergillus niger: The Effects of Organic Acids Biosynthesis

2007 ◽  
Vol 20-21 ◽  
pp. 111-114
Author(s):  
Mohammad Pazouki ◽  
M.R. Hosseini ◽  
M. Ranjbar ◽  
F. Ghavipanjeh
Keyword(s):  
Citric Acid ◽  
Aspergillus Niger ◽  
Oxalic Acid ◽  
Organic Acids ◽  
Iron Removal ◽  
Pulp Density ◽  
High Iron Content ◽  
Pistachio Shell ◽  
Strain Type ◽  
Different Strains

In this work, bioleaching of iron from a kaolin sample was carried out using two different strains of Aspergillus niger, and the effects of strain type, pulp density, and addition time of clay on the iron removal were investigated using a full factorial design. It is concluded that strain type has the most significant effect on the iron removal. Also, the highest removal extent was 42.8% that was achieved by using the strain isolated from pistachio shell at the pulp density of 20 g/l, when the clay was added at the beginning of the experiments. The results showed that for the experiments in which the clay was added in the first day of cultivation, the average organic acids concentration (citric acid: 5.6 g/l, and oxalic acid: 4.54 g/l) were higher in comparison to those experiments in which the clay was added in the third day (citric acid: 5.25 g/l, and oxalic acid: 2.87).

scholarly journals Oxalic acid production by Aspergillus niger: an oxalate-non-producing mutant produces citric acid at pH 5 and in the presence of manganese

Microbiology ◽  
1999 ◽  
Vol 145 (9) ◽  
pp. 2569-2576 ◽  
Author(s):  
George J. G. Ruijter ◽  
Peter J. I. van de Vondervoort ◽  
Jaap Visser
Keyword(s):  
Citric Acid ◽  
Aspergillus Niger ◽  
Oxalic Acid ◽  
Acid Production

Optimization of Kaolin Bioleaching by Aspergillus niger

2007 ◽  
Vol 20-21 ◽  
pp. 115-118 ◽  
Author(s):  
M. Ranjbar ◽  
E. Aghaie ◽  
M.R. Hosseini ◽  
Mohammad Pazouki ◽  
F. Ghavipanjeh
Keyword(s):  
Aspergillus Niger ◽  
Ph Value ◽  
Iron Concentration ◽  
Iron Removal ◽  
Pistachio Shell ◽  
Dissolved Iron ◽  
Initial Ph ◽  
Negative Effect ◽  
Concentration Changes ◽  
Central Composite

In this paper, a central composite design was applied to optimize the bioleaching of iron from a kaolin sample containing 2.2% iron impurity by Aspergillus niger isolated from pistachio shell. The strains were inoculated into 500 ml flasks containing 100 ml media consisted of (g/l): sucrose 120; NH4NO3 0.45; KH2PO4 0.1; MgSO4.7H2O 0.3; FeSO4.7H2O 10-4; ZnSO4.7H2O 25×10- 5. The effects of initial pH, sugar and spore concentrations on iron removal extent were investigated. The two-level factorial design points were pH 2 and 5, sugar conc. 70 g/l and 130 g/l, spore conc. 9×107 and 35×107 spores/l. Also, the increase of dissolved iron, oxalic acid concentration, changes in pH value, and sugar concentration were registered. Consequently, after 10 days, the iron concentration of the best condition reached to 179.3 ppm that means 38.8% of the total iron content is removed. Furthermore, the data analysis showed that all the factors are significant, and the iron removal extent increases by increasing the initial pH to 4.4, sucrose content to 93.8 g/l, and spore concentration to 305.5 spores/μl, but further increase in each factor value has negative effect on the response.

Effects and Mechanism of Organic Acids on Aluminum Availability of Dark Brown Forest Soil

2011 ◽  
Vol 393-395 ◽  
pp. 709-712 ◽  
Author(s):  
Fu Xing Cui ◽  
Jin Feng Song ◽  
Ya Fen Guo ◽  
Jin Zhong Xu
Keyword(s):  
Citric Acid ◽  
Oxalic Acid ◽  
Organic Acids ◽  
Organic Acid ◽  
Forest Soil ◽  
Dissociation Constants ◽  
Organic Salt ◽  
Brown Forest Soil ◽  
Organic Salts ◽  
Complexation Reactions

The effects and mechanism of different concentration organic acids and organic salts solution on Al availability of dark brown forest soil were studied. It was resulted that, oxalic acid/oxalate and citric acid/citrate substantially stimulated soil Al release of dark brown forest soil. The effect of organic acids/salts on Al release would be strengthen with increasing of their concentrations.The contents of Al released from A1 horizon was higher than that from B horizon. Organic salt solutions had much higher effects than organic acid the same in concentration, i.e. citrate>citric acid, oxalate>oxalic acid. Therefore, the mechanism of organic acid/salts triggering release of soil Al was assumed to be dominated by complexation reactions of organic anions. Citric acid/ citrate had much higher effect than oxalic acid/ oxalate at same concentration to A1 and B horizons, i.e. citrate> oxalate, citric acid>oxalic acid, which was primarily related with the greater complexing capacities and dissociation constants of citric acid.

The enthalpies of dilution of aqueous organic acids: oxalic acid and citric acid at 298.15 K

1990 ◽  
Vol 22 (2) ◽  
pp. 167-172 ◽  
Author(s):  
Celina Dobrogowska ◽  
Loren G Hepler ◽  
Alexander Apelblat
Keyword(s):  
Citric Acid ◽  
Oxalic Acid ◽  
Organic Acids ◽  
Enthalpies Of Dilution

scholarly journals Organic Acid Profile of “Batuan” (Garcinia binucao [Blco] Choisy) Fruit

2017 ◽  
pp. 25-33 ◽  
Author(s):  
Elizabeth Quevedo ◽  
Erlinda Dizon ◽  
Florinia Merca
Keyword(s):  
Acetic Acid ◽  
Lactic Acid ◽  
Citric Acid ◽  
Oxalic Acid ◽  
Organic Acids ◽  
Organic Acid ◽  
Fumaric Acid ◽  
Mobile Phase ◽  
Fruit Samples ◽  
Organic Acid Profile

“Batuan” fruit (Garcinia binucao [Blco.] Choisy), an indigenous acidulant grown in the Visayas State University, Baybay City, Leyte was analyzed for its organic acid profile at different stages of maturity for the development of potential food and non-food products. The analysis of organic acid content was done using Reverse Phase-High Performance Liquid Chromatography. Organic acids in the dried, powdered “batuan” fruit samples were extracted with the mobile phase (50mM KH2PO4/ H3PO4, pH2.8). The sample extracts and organic acid standards (oxalic acid, tartaric acid, malic acid, citric acid, fumaric acid, lactic acid, acetic acid, and succinic acid) were injected to RP-HPLC under isocratic elution with the mobile phase at a flow rate of 1.0mL min-1 and using UV-vis detection at 210nm. “Batuan” fruit samples contain oxalic acid, tartaric acid, malic acid, citric acid, fumaric acid, succinic acid, acetic acid, lactic acid, and a few unidentified organic acids. Among the organic acids present, citric acid accumulated the highest in the ripe “batuan” fruit; fumaric acid, the least. Results of this study show that “batuan” fruit could be a good natural source of acidulant for food and non-food applications.

scholarly journals Exogenous Oxalic Acid and Citric Acid Improve Lead (Pb) Tolerance of Larix olgensis A. Henry Seedlings

Forests ◽  
2018 ◽  
Vol 9 (9) ◽  
pp. 510 ◽  
Author(s):  
JinFeng Song ◽  
Daniel Markewitz ◽  
Shaoping Wu ◽  
Ying Sang ◽  
Chengwei Duan ◽  
...  
Keyword(s):  
Citric Acid ◽  
Plant Growth ◽  
Oxalic Acid ◽  
Organic Acids ◽  
Resistance Mechanism ◽  
Resistance Mechanisms ◽  
Internal Resistance ◽  
Larix Olgensis ◽  
Detoxification Mechanism

We investigated the beneficial role of different concentrations of exogenous oxalic acid (OA) or citric acid (CA) for improving Pb tolerance and mitigating Pb-induced physiological toxicity in Changbai larch (Larix olgensis A. Henry) seedlings in northeast China. The seedlings were exposed to 100 mg·kg−1 Pb in soil alone or in combination with OA or CA irrigation for 10, 20, or 30 days. Pb-induced damage in L. olgensis was evident from elevated lipid peroxidation that significantly inhibited plant growth. Malondialdehyde (MDA) contents also increased in the presence of elevated Pb; however, superoxide dismutase (SOD) and peroxidase (POD) activities, as well as proline and pigment contents, all decreased. The damage increased in controls over the application periods. Pb contents in fine roots and leaves generally decreased with low-concentration organic acids (<1.0 mmol·L−1), but often increased at 5.0 and 10.0 mmol·L−1. Alternatively, when Pb-stressed plants were exposed to an organic acid (especially 5.0 or 10.0 mmol·L−1 for 10 days), the damage, as indicated by the physiological parameters, was reversed, and plant growth was promoted; CA was more effective in inducing these changes than OA. Therefore, exogenous organic acids have the potential to alleviate Pb-induced oxidative injuries, and can improve the tolerance of L. olgensis seedlings to Pb stress. Under lower OA and CA concentrations, the detoxification mechanism appears to be an external resistance mechanism; however, under higher concentrations (5.0–10.0 mmol·L−1) internal resistance mechanisms appear dominant. It is also possible that the two mechanisms work in tandem.

Urinary organic acids: isolation and quantification for routine metabolic screening.

1987 ◽  
Vol 33 (4) ◽  
pp. 473-480 ◽  
Author(s):  
J Greter ◽  
C E Jacobson
Keyword(s):  
Lactic Acid ◽  
Citric Acid ◽  
Ion Exchange ◽  
Oxalic Acid ◽  
Organic Acids ◽  
Screening Method ◽  
Detector Response ◽  
Inborn Errors ◽  
Exchange Method ◽  
Metabolic Screening

Abstract A method for isolating organic acids from acidified urine on an equivolume mixture of Porapak Q and Porapak T is described, and results are compared with extraction with ethyl acetate and ion exchange on DEAE-Sephadex. Average recoveries of 14C-labeled oxalic acid, lactic acid, succinic acid, alpha-ketoglutaric acid, citric acid, and cinnamic acid were equal to or better than those obtained with the solvent-extraction method. The ion-exchange method gave higher recoveries for oxalic acid, lactic acid, and citric acid. The quantification of separated acids from reconstructed mass spectrometric ion traces is compared with quantification from the simultaneously recorded flame ionization detector response signals. A good correlation was obtained. With the present routine metabolic screening method we have detected several patients with inborn errors of metabolism.

scholarly journals Processing of Waste Copper Converter Slag Using Organic Acids for Extraction of Copper, Nickel, and Cobalt

Minerals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 290 ◽  
Author(s):  
Pratima Meshram ◽  
Uday Prakash ◽  
Lalit Bhagat ◽  
Abhilash ◽  
Hongbo Zhao ◽  
...  
Keyword(s):  
Citric Acid ◽  
Organic Acids ◽  
Converter Slag ◽  
Pulp Density ◽  
Hydrometallurgical Process ◽  
X Ray ◽  
Pourbaix Diagrams ◽  
Leaching Experiments ◽  
Environmentally Sound ◽  
Optimum Recovery

An innovative, economical, and environmentally sound hydrometallurgical process has been proposed for recovering Cu, Ni, and Co from copper-rich converter slag by organic acids. In the leaching experiments, the effects of organic acid concentrations, pulp density, temperature, and time were investigated. Optimum recovery of 99.1% Cu, 89.2% Ni, 94% Co, and 99.2% Fe was achieved in 9–10 h at 308 K (35 °C) temperature and 15% pulp density with 2 N citric acid using <45 µm particles. Pourbaix diagrams of metal-water-citrate systems were supplemented to examine solubility of ligands at the desired conditions. Furthermore, the leaching mechanism was based on the SEM-EDS (energy-dispersive X-ray spectroscopy) and XRD characterization as well as the leaching results obtained.

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