FISH Analysis of Bacterial Attachment to Copper Sulfides in Bioleaching Processes

2009 ◽  
Vol 71-73 ◽  
pp. 329-332
Author(s):  
J. Huergo ◽  
C. Bernardelli ◽  
M. Viera ◽  
Wolfgang Sand ◽  
Edgardo R. Donati
Keyword(s):  
Cell Attachment ◽  
Sulfide Oxidation ◽  
Metal Sulfide ◽  
Bacterial Attachment ◽  
Water Soluble ◽  
Soluble Form ◽  
Metal Sulfides ◽  
Fish Analysis ◽  
Acidithiobacillus Thiooxidans ◽  
Copper Sulfides

Bioleaching is the biological conversion of an insoluble metal compound into a water soluble form. In this process metal sulfides are oxidized to metal ions and sulfate by acidophilic microorganisms capable of oxidizing Fe2+ and/or sulfur-compounds. The metal solubilization from sulfide minerals is a chemical process which requires Fe3+ reduction. It is an environmentally friendly technique and an economical method for recovering metals that requires low investment and operation costs. In this work we studied the bioleaching of two kinds of acid-soluble copper sulfides, one easily leached by mesophilic bacteria (covellite), and the other one refractory to their activity (chalcopyrite), in acidic media with or without Fe2+ ions. We studied attached and planktonic populations of autotrophic bacteria, such as Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans and Leptospirillum ferrooxidans in pure or mixed cultures. The influence of a heterotrophic microorganism, Acidiphilium cryptum, was also studied. Attachment was evaluated with fluorescence staining and FISH using four specific probes. L. ferrooxidans showed highest initial attachment in all cases. The presence of Ap. cryptum increased the cell attachment compared with the autotrophic pure cultures. It was possible to correlate experimental data with a mechanism of bacterial-metal sulfide oxidation, the polysulfide pathway for acid- soluble metal sulfides.

Oxidation of Copper Sulfides in Aqueous Ammonia. I. Formation of Sulfur

1979 ◽  
Vol 32 (5) ◽  
pp. 961 ◽  
Author(s):  
AO Filmer ◽  
AJ Parker ◽  
LGB Wadley
Keyword(s):  
Ammonium Sulfate ◽  
Aqueous Ammonia ◽  
Copper Ions ◽  
Sulfide Oxidation ◽  
Metal Sulfide ◽  
Metal Sulfides ◽  
Copper Sulfides ◽  
Consecutive Reactions ◽  
Partial Pressures ◽  
Sulfur Containing

Elemental sulfur, rather than sulfate or thiosulfate ions, is the major sulfur-containing product when CuS or Cu2S are oxidized at temperatures below 40� with oxygen in a large excess of aqueous ammonia containing ammonium sulfate at pH 10-10.5. At temperatures above 60�, or in solutions containing low proportions of ammonia or ammonium sulfate, very little sulfur is formed. Higher partial pressures of oxygen lead to higher proportions of sulfur. These observations are explained in terms of concurrent and consecutive reactions involving copper polysulfides. The high proportion of ammonia to soluble copper ions which is required imposes some practical limitations on any potential leaching process aimed at producing sulfur. Proportions of sulfur from metal sulfide oxidation in aqueous ammonia decrease in the series of metal sulfides, Cu2S > CuS > NiS > FeS > ZnS > CoS. Some aspects of the chemistry of sulfur in aqueous ammonia are discussed.

Oxidation of Copper Sulfides in Aqueous Ammonia. III. Kinetic Characteristics

1979 ◽  
Vol 32 (12) ◽  
pp. 2597 ◽  
Author(s):  
AO Filmer ◽  
AJ Parker ◽  
BW Clare ◽  
LGB Wadley
Keyword(s):  
Aqueous Ammonia ◽  
Sulfide Oxidation ◽  
Metal Sulfide ◽  
Diffusion Control ◽  
Sulfate Ions ◽  
Kinetics Of Oxidation ◽  
Copper Sulfides ◽  
Shrinking Core ◽  
Kinetics Of ◽  
And Diffusion

The kinetics of oxidation with oxygen of chalcocite, Cu2S, to CuS in buffered aqueous ammonia at pH 10.5 at 30� can be modeled approximately by a shrinking core of Cu2S within a thickening shell of CuxS (x ≥ 1). The Cu2S core offers partial cathodic protection to the CuxS and diffusion of Cu+ through CuxS controls the rate of reaction. The kinetics of oxidation of covellite, CuS, to Cu2+, sulfur and sulfate ions in the same solvent can be modeled by a shrinking core of CuS surrounded by a shrinking sphere of CuyS (y < 1) which is much less effectively protected cathodically by the CuS core. Oxidation of CuS is subject to mixed chemical and diffusion control. Rates of oxidation of NiS and of CuS, in the presence and absence of tetrachloroethene and ammonium sulfate, show that, whether sulfur is a major oxidation product or not, the presence of sulfur has very little, if any, influence on the rate or mechanism of oxidation. This is contrary to current ideas on metal sulfide oxidation.

scholarly journals Comparative Analysis of Attachment to Chalcopyrite of Three Mesophilic Iron and/or Sulfur-Oxidizing Acidophiles

Minerals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 406 ◽  
Author(s):  
Qian Li ◽  
Baojun Yang ◽  
Jianyu Zhu ◽  
Hao Jiang ◽  
Jiaokun Li ◽  
...  
Keyword(s):  
Adhesion Force ◽  
Bacterial Attachment ◽  
Copper Recovery ◽  
Metal Sulfides ◽  
Acidithiobacillus Thiooxidans ◽  
Adhesion Forces ◽  
Force Microscopy ◽  
Atomic Force ◽  
Initial Adhesion ◽  
Sulfur Oxidizing

Adhesion plays an important role in bacterial dissolution of metal sulfides, since the attached cells initiate the dissolution. In addition, biofilms, forming after bacterial attachment, enhance the dissolution. In this study, interactions between initial adhesion force, attachment behavior and copper recovery were comparatively analyzed for Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans, and Leptospirillum ferrooxidans during bioleaching of chalcopyrite. The adhesion forces between bacteria and minerals were measured by atomic force microscopy (AFM). L. ferrooxidans had the largest adhesion force and attached best to chalcopyrite, while A. ferrooxidans exhibited the highest bioleaching of chalcopyrite. The results suggest that the biofilm formation, rather than the initial adhesion, is positively correlated with bioleaching efficiency.

Fundamental Studies of Bacterial Leaching Using Bio-Physical Techniques of Transmission Electron Microscopy

1975 ◽  
Vol 33 ◽  
pp. 644-645
Author(s):  
V.K. Berry ◽  
L.E. Murr
Keyword(s):  
Bacterial Attachment ◽  
Water Soluble ◽  
Metal Sulfides ◽  
Bacterial Leaching ◽  
Research Areas ◽  
Transmission Electron ◽  
Further Development ◽  
Soluble Sulfates ◽  
Metallurgical Processes

The role of microorganisms and their reaction with minerals are comparatively newer research areas in the general area of chemical mining, and have considerable scope of further development. The most commonly studied reactions of this type have been associated with microorganisms characterized as Thiobacillus thio-oxidans and Thiobacillus ferroxidans. These microorganisms have the ability to oxidize heavy metal sulfides and elemental sulfur to water soluble sulfates; and ferrous iron to ferric iron.The attachment location of biological microorganisms on minerals has not been reported in the literature as it relates specifically to biogenic metallurgical processes, although an attempt to describe the mode and character of bacterial attachment has been made by some workers. In the current investigation, a thermophillic microbe previously described by Brierley and Brierley and suggested to have a relationship with Sulfolobus was used. This microorganism exhibits an intracellular retractile body un-like Sulfolobus.

scholarly journals Automated Microscopic Analysis of Metal Sulfide Colonization by Acidophilic Microorganisms

2018 ◽  
Vol 84 (20) ◽  
Author(s):  
Sören Bellenberg ◽  
Antoine Buetti-Dinh ◽  
Vanni Galli ◽  
Olga Ilie ◽  
Malte Herold ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Cell Attachment ◽  
Metal Sulfide ◽  
Microbial Colonization ◽  
Epifluorescence Microscopy ◽  
Recent Analysis ◽  
Metal Sulfides ◽  
Content Type ◽  
Batch Cultures ◽  
Biofilm Dispersal

ABSTRACTIndustrial biomining processes are currently focused on metal sulfides and their dissolution, which is catalyzed by acidophilic iron(II)- and/or sulfur-oxidizing microorganisms. Cell attachment on metal sulfides is important for this process. Biofilm formation is necessary for seeding and persistence of the active microbial community in industrial biomining heaps and tank reactors, and it enhances metal release. In this study, we used a method for direct quantification of the mineral-attached cell population on pyrite or chalcopyrite particles in bioleaching experiments by coupling high-throughput, automated epifluorescence microscopy imaging of mineral particles with algorithms for image analysis and cell quantification, thus avoiding human bias in cell counting. The method was validated by quantifying cell attachment on pyrite and chalcopyrite surfaces with axenic cultures ofAcidithiobacillus caldus,Leptospirillum ferriphilum, andSulfobacillus thermosulfidooxidans.The method confirmed the high affinity ofL. ferriphilumcells to colonize pyrite and chalcopyrite surfaces and indicated that biofilm dispersal occurs in mature pyrite batch cultures of this species. Deep neural networks were also applied to analyze biofilms of different microbial consortia. Recent analysis of theL. ferriphilumgenome revealed the presence of a diffusible soluble factor (DSF) family quorum sensing system. The respective signal compounds are known as biofilm dispersal agents. Biofilm dispersal was confirmed to occur in batch cultures ofL. ferriphilumandS. thermosulfidooxidansupon the addition of DSF family signal compounds.IMPORTANCEThe presented method for the assessment of mineral colonization allows accurate relative comparisons of the microbial colonization of metal sulfide concentrate particles in a time-resolved manner. Quantitative assessment of the mineral colonization development is important for the compilation of improved mathematical models for metal sulfide dissolution. In addition, deep-learning algorithms proved that axenic or mixed cultures of the three species exhibited characteristic biofilm patterns and predicted the biofilm species composition. The method may be extended to the assessment of microbial colonization on other solid particles and may serve in the optimization of bioleaching processes in laboratory scale experiments with industrially relevant metal sulfide concentrates. Furthermore, the method was used to demonstrate that DSF quorum sensing signals directly influence colonization and dissolution of metal sulfides by mineral-oxidizing bacteria, such asL. ferriphilumandS. thermosulfidooxidans.

scholarly journals Analyzing the Carotenoid Composition of Melilot (Melilotus officinalis (L.) Pall.) Extracts and the Effects of Isolated (All-E)-lutein-5,6-epoxide on Primary Sensory Neurons and Macrophages

Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 503
Author(s):  
Györgyi Horváth ◽  
Eszter Csikós ◽  
Eichertné Violetta Andres ◽  
Tímea Bencsik ◽  
Anikó Takátsy ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Sensory Neurons ◽  
Biological Activities ◽  
Water Soluble ◽  
Soluble Form ◽  
Primary Sensory Neurons ◽  
Isolation And Identification ◽  
Melilotus Officinalis ◽  
Carotenoid Composition ◽  
Anti Inflammatory

Melilotus officinalis is known to contain several types of secondary metabolites. In contrast, the carotenoid composition of this medicinal plant has not been investigated, although it may also contribute to the biological activities of the drug, such as anti-inflammatory effects. Therefore, this study focuses on the isolation and identification of carotenoids from Meliloti herba and on the effect of isolated (all-E)-lutein 5,6-epoxide on primary sensory neurons and macrophages involved in nociception, as well as neurogenic and non-neurogenic inflammatory processes. The composition of the plant extracts was analyzed by high performance liquid chromatography (HPLC). The main carotenoid was isolated by column liquid chromatography (CLC) and identified by MS and NMR. The effect of water-soluble lutein 5,6-epoxide-RAMEB (randomly methylated-β-cyclodextrin) was investigated on Ca2+-influx in rat primary sensory neurons induced by the activation of the transient receptor potential ankyrin 1 receptor agonist to mustard-oil and on endotoxin-induced IL-1β release from isolated mouse peritoneal macrophages. (all-E)-Lutein 5,6-epoxide significantly decreased the percent of responsive primary sensory neurons compared to the vehicle-treated stimulated control. Furthermore, endotoxin-evoked IL-1β release from macrophages was significantly decreased by 100 µM lutein 5,6-epoxide compared to the vehicle-treated control. The water-soluble form of lutein 5,6-epoxide-RAMEB decreases the activation of primary sensory neurons and macrophages, which opens perspectives for its analgesic and anti-inflammatory applications.

scholarly journals Human Lanosterol 14-Alpha Demethylase (CYP51A1) Is a Putative Target for Natural Flavonoid Luteolin 7,3′-Disulfate

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2237
Author(s):  
Leonid Kaluzhskiy ◽  
Pavel Ershov ◽  
Evgeniy Yablokov ◽  
Tatsiana Shkel ◽  
Irina Grabovec ◽  
...  
Keyword(s):  
Cholesterol Metabolism ◽  
Cholesterol Biosynthesis ◽  
Clinical Importance ◽  
Optical Biosensor ◽  
Water Soluble ◽  
Soluble Form ◽  
Redox Partner ◽  
Access Channel ◽  
Kd Values ◽  
Key Steps

Widespread pathologies such as atherosclerosis, metabolic syndrome and cancer are associated with dysregulation of sterol biosynthesis and metabolism. Cholesterol modulates the signaling pathways of neoplastic transformation and tumor progression. Lanosterol 14-alpha demethylase (cytochrome P450(51), CYP51A1) catalyzes one of the key steps in cholesterol biosynthesis. The fairly low somatic mutation frequency of CYP51A1, its druggability, as well as the possibility of interfering with cholesterol metabolism in cancer cells collectively suggest the clinical importance of CYP51A1. Here, we show that the natural flavonoid, luteolin 7,3′-disulfate, inhibits CYP51A1 activity. We also screened baicalein and luteolin, known to have antitumor activities and low toxicity, for their ability to interact with CYP51A1. The Kd values were estimated using both a surface plasmon resonance optical biosensor and spectral titration assays. Unexpectedly, in the enzymatic activity assays, only the water-soluble form of luteolin—luteolin 7,3′-disulfate—showed the ability to potently inhibit CYP51A1. Based on molecular docking, luteolin 7,3′-disulfate binding suggests blocking of the substrate access channel. However, an alternative site on the proximal surface where the redox partner binds cannot be excluded. Overall, flavonoids have the potential to inhibit the activity of human CYP51A1 and should be further explored for their cholesterol-lowering and anti-cancer activity.

ZnO nanorods decorated with metal sulfides as stable and efficient counter-electrode materials for high-efficiency quantum dot-sensitized solar cells

2016 ◽  
Vol 4 (21) ◽  
pp. 8161-8171 ◽  
Author(s):  
Chandu V. V. M. Gopi ◽  
Mallineni Venkata-Haritha ◽  
Young-Seok Lee ◽  
Hee-Je Kim
Keyword(s):  
Solar Cells ◽  
Quantum Dot ◽  
Counter Electrode ◽  
Electrode Materials ◽  
High Efficiency ◽  
Zno Nanorods ◽  
Metal Sulfide ◽  
Metal Sulfides ◽  
Sensitized Solar Cells

Metal sulfide decorated with ZnO NRs (ZnO/CoS, ZnO/NiS, ZnO/CuS and ZnO/PbS) were fabricated and used as efficient CEs for QDSSCs.

scholarly journals Studies on silk proteins I. The properties and constitution of fibroin. The conversion of fibroin into a water-soluble form and its bearing on the phenomenon of denaturation

1947 ◽  
Vol 190 (1021) ◽  
pp. 145-169 ◽  
Keyword(s):  
Molecular Weight ◽  
Soluble Protein ◽  
Optical Rotation ◽  
Amino Nitrogen ◽  
Water Soluble ◽  
Soluble Form ◽  
Secondary Process ◽  
Amide Nitrogen ◽  
Water Soluble Protein ◽  
The Mean

Some of the constituent amino-acids of fibroin (degummed silk) are determined. Special attention is directed to histidine, owing to its use in the calculation of the molecular weight of fibroin. A value of 0⋅45% has been found by methods in which the histidine is isolated as nitranilate or di-(3:4-dichlorobenzenesulphonate). Other values obtained are serine 12⋅6%, threonine 1⋅5%, tyrosine 10⋅6%, and proline 1⋅5%. Hydroxyproline appears to be absent, but the presence of small amounts of some hydroxyamino-acid other than serine and threonine is indicated. The mean residue weight of fibroin is determined by three methods, one of which is a new method based on analysis of the complex formed between fibroin and cupri-ethylenediamine. This method gives a Cu:fibroin-N ratio of 1:1⋅92 and, if allowance is made for co-ordination with the tyrosine hydroxy1 group, an equivalence of 1⋅964 atoms of peptide-nitrogen to 1 atom of copper is obtained. The three methods give an average value of 78⋅0 for the mean residue weight of fibroin. This value, together with the most acceptable data for amino-acid constituents, indicate that the unidentified anhydro-residues (about 20%) have a mean residue weight of about 107. Evidence is presented that fibroin contains no amide-nitrogen. Methods for the determination of amide-nitrogen at present in use, which indicate a content of 1 to 2%, are considered to be unreliable. Fibroin dissolved in cupri-ethylenediamine gives, on neutralization and dialysis of the resulting solution, a water-soluble protein. The production of this water-soluble protein is attended by little or no degradation of the original fibroin as shown by determinations of fluidity, amino-nitrogen, and acid- and alkali-combining power. The water-soluble protein is precipitated by the normal protein-precipitating reagents, but in every instance examined the precipitated material exhibits an insolubility comparable with that of the original fibroin. Factors responsible for the solubilization process are investigated and data for molecular weight, titration values, ultra-violet absorption spectra, reducing activity, optical rotation, tryptic hydrolysis, and viscosity for both soluble and dispersed fibroin are given. Soluble fibroin has [ α ] D 15 — 53⋅1° and dispersed fibroin [ α ] D 15 — 58⋅9°, both in aqueous media. The preparation and properties of films and filaments of fibroin are described. Films of fibroin can be prepared that are water-soluble. On stretching, these films show strain-birefringence, acquire considerable tensile strength, and become insoluble in water, but X-ray examination gives the β -keratin pattern for both the stretched and unstretched films. Reasons are advanced for considering the water-soluble form of fibroin to be the native or renatured protein and the original protein to be the denatured form. The denaturation of fibroin is discussed on the basis that denaturation is essentially an unfolding of a coiled long-chain molecule. The subsequent aggregation of the uncoiled molecules to give an insoluble product is considered to be a secondary process. Some aspects of protein and polypeptide chains as macro-molecules are also discussed.

THE ABSORPTION OF VITAMIN A IN PREMATURELY BORN INFANTS

PEDIATRICS ◽  
1948 ◽  
Vol 1 (4) ◽  
pp. 505-511
Author(s):  
STEWART H. CLIFFORD ◽  
KATHLEEN FAHEY WELLER
Keyword(s):  
Vitamin A ◽  
Premature Infants ◽  
Test Dose ◽  
Water Soluble ◽  
Soluble Form ◽  
Oral Ingestion ◽  
Retrolental Fibroplasia ◽  
Practical Advantage ◽  
The Mean ◽  
Absorption Level

Forty-two premature infants were tested for vitamin A absorption after the oral ingestion of 0.5 cc. (35,000 U.S.P. units) of percomorph liver oil. Only three (7%) showed good absorption levels. The mean absorption level found from three to five hours after the test dose was 16 units of vitamin A. Forty-one were tested for vitamin A absorption after the oral ingestion of either 2 cc. or 3 cc. (16,000-24,000 U.S.P. units) of vitamin A in a vehicle of either alcohol or propylene glycol. Of these 37 (90%) showed good absorption levels. The mean absorption level found from three to five hours after the test dose was 85 units of vitamin A. Retrolental fibroplasia could not be prevented from developing in a certain number of premature infants' eyes by the daily oral administration of 5000 U.S.P. of vitamin A in an absorbable water soluble form. Even the addition of 20,000 U.S.P. units of vitamin A in oil by intramuscular injection failed to prevent the development of bilateral retrolental fibroplasia in one infant. If vitamin D follows the same laws of absorption as does vitamin A, the provision of both A and D in a readily absorbable form should be of great practical advantage to the prematurely born infant.

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