Pretreatment of Refractory Gold Ores Using Cell-Free Extracts of P. chrysosporium: A Preliminary Study

2013 ◽  
Vol 825 ◽  
pp. 427-430 ◽  
Author(s):  
Grace Ofori-Sarpong ◽  
Kwadwo Osseo-Asare ◽  
Ming Tien
Keyword(s):  
Gold Recovery ◽  
Active Components ◽  
Gold Extraction ◽  
Promising Alternative ◽  
Gold Ores ◽  
Refractory Gold Ores ◽  
In Vitro Processing ◽  
Refractory Gold

The fungus Phanerochaete chrysosporium has been proven to biotransform refractory gold ores, leading to increase in gold recovery. This transformation has been attributed to enzymes secreted by the microbe. This paper reports the findings of preliminary investigations aimed at assessing the use of hydrogen peroxide and cell-free extracts from the fungus, P. chrysosporium, to effect biotransformation of sulphidic refractory gold ores. The investigations show that the total dissolved arsenic, iron and sulphur in solution were up to 5.2 wt%, 0.9 wt% and 6.0 wt% respectively from flotation concentrate after 72 hrs of treatment. Analysis for sulphide sulphur in the residual solids of the gold concentrate indicated about 25 wt% oxidation within 24 hours of treatment. In general, cell-free decomposition of the samples did not increase beyond 24 hours of contact time, possibly due to exhaustion of the active components. Gold extraction by cyanidation increased by 24% after 24-hr treatment with the cell-free extracts. Comparatively, cell-free (in vitro) treatment recorded 66% overall gold recovery as against 61% for whole cell (in vivo) after 72 hours of treatment. These initial results indicate clearly that in vitro processing is a promising alternative to in vivo processing of refractory gold ores using P. chrysosporium.

scholarly journals Bio-Oxidation of a Double Refractory Gold Ore and Investigation of Preg-Robbing of Gold from Thiourea Solution

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1216
Author(s):  
Rui Xu ◽  
Qian Li ◽  
Feiyu Meng ◽  
Yongbin Yang ◽  
Bin Xu ◽  
...  
Keyword(s):  
Mixed Culture ◽  
Active Sites ◽  
Gold Recovery ◽  
Ftir Analysis ◽  
Gold Extraction ◽  
Gold Ores ◽  
Gold Ore ◽  
Thiourea Solution ◽  
Refractory Gold ◽  
Pure Cultures

Carbonaceous sulfidic gold ores are commonly double refractory and thus require pretreatment before gold extraction. In this paper, the capacity of pre-bio-oxidation can simultaneously decompose sulfides or deactivate carbonaceous matters (CM) from a double refractory gold ore (DRGO) using pure cultures of A. ferrooxidans or L. ferrooxidans, and a mixed culture containing A. ferrooxidans and L. ferrooxidans was investigated. The results showed that direct thiourea leaching of the as-received DRGO yielded only 28.7% gold extraction, which was due to the encapsulation of sulfides on gold and the gold adsorption of CM. After bio-oxidation, thiourea leaching of the DRGO resulted in gold extraction of over 75–80%. Moreover, bio-oxidation can effectively reduce the adsorption of carbon to gold. XRD, SEM-EDS and FTIR analysis showed that many oxygen-containing groups were introduced on the surface of DRGO during bio-oxidation, while the C=C bond was cleaved and the O–C–O and C–N bonds were degraded, causing a decrease in active sites for gold adsorption. Moreover, passivation materials such as jarosite were formed on the surface of DRGO, which might reduce the affinity of CM for gold in solutions. In addition, the cleavage of the S–S band indicated that sulfides were oxidized by bacteria. This work allows us to explain the applicability of pre-bio-oxidation for degrading both sulfides and CM and increasing gold recovery from DRGO in the thiourea system.

scholarly journals Analysis of the Microbial Community Associated with a Bioprocess System for Bioremediation of Thiocyanate- and Cyanide-Laden Mine Water Effluents

2015 ◽  
Vol 1130 ◽  
pp. 614-617 ◽  
Author(s):  
Robert J. Huddy ◽  
Rose Kantor ◽  
Wynand van Zyl ◽  
Robert P. van Hille ◽  
Jillian F. Banfield ◽  
...  
Keyword(s):  
Microbial Culture ◽  
Process Optimisation ◽  
Gold Extraction ◽  
Mixed Microbial Culture ◽  
Metabolic Potential ◽  
Gold Ores ◽  
Refractory Gold Ores ◽  
Refractory Gold ◽  
Key Microorganisms ◽  
Activated Sludge Processes

Gold extraction by cyanidation from refractory gold ores results in the formation of thiocyanate-and cyanide-contaminated wastewater effluents that must be treated before recycle or discard. Activated sludge processes, such as ASTERTM, can be used for biodegradation of these effluent streams. The destruction of these compounds is catalyzed by a mixed microbial culture, however, very little is known about the community composition and metabolic potential of the thiocyanate-and cyanide-degrading microorganisms within the community. Here we describe our on-going attempts to better understand the key microorganisms, within the ASTERTM bioprocess, that contribute to the destruction of thiocyanate and cyanide, and how this knowledge relates to further process optimisation.

scholarly journals THE GOLD RECOVERY CLEAN TECHNOLOGY FROM REFRACTORY GOLD ORES USING MICROWAVES’ ENERGY

2018 ◽  
Author(s):  
Nicolae Tomus ◽  
◽  
Marius Zlagnean ◽  
Ioana-Carmen Popescu (Hostuc)
Keyword(s):  
Clean Technology ◽  
Gold Recovery ◽  
Gold Ores ◽  
Refractory Gold Ores ◽  
Refractory Gold

Biooxidation of High-Sulfur Refractory Gold Concentrate by Ferroplasma acidiphilum

2014 ◽  
Vol 997 ◽  
pp. 642-645 ◽  
Author(s):  
He Shang ◽  
Jian Kang Wen ◽  
Biao Wu
Keyword(s):  
Pulp Density ◽  
Cyanide Leaching ◽  
Gold Extraction ◽  
Pressure Oxidation ◽  
Gold Ores ◽  
Refractory Gold Ores ◽  
Refractory Gold ◽  
Initial Ph ◽  
Pre Treatment ◽  
Number Of Bacteria

Gold ores can be categorized into two types-free milling and refractory. Free milling ores are easy to treat. Gold in such ores is recovered by gravity separating techniques or direct cyanidation. Refractory gold ores, on the contrary, are difficult to treat and require pre-treatment prior to cyanidation, such as roasting, pressure oxidation, fine grinding and biooxidation. A number of bacteria are used in biomining but the prominent ones that are known to be involved in the oxidation of sulfide ores include Thiobacillusferrooxidans, Thiobacillus thiooxidans and Leptospirillum ferrooxidans. In this study, the gold concentrate was biooxidized in a reactor at 45°C over a period of 10 days at a pulp density of 15% solids using a culture of already grown Ferroplasma acidiphilum. The initial pH was adjusted to 1.5 with sulfuric acid, resulted in 85.39 % oxidation of sulfur from initial grade of 33.83 %, and the slag rate was 68.52 %. The products of sulfide biooxidation were leached at a pulp density of 20 %(v/w) for 24 h at pH 11. The pH was adjusted using CaO and cyanide strength was 10 kg/t, we got a gold extraction of 90.71 %, which ncreaseed 80.09 % compared with the direct cyanide leaching.

scholarly journals Inhibitory Effect of Sargassum fusiforme and Its Components on Replication of Respiratory Syncytial Virus In Vitro and In Vivo

Viruses ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 548
Author(s):  
Kiramage Chathuranga ◽  
Asela Weerawardhana ◽  
Niranjan Dodantenna ◽  
Lakmal Ranathunga ◽  
Won-Kyung Cho ◽  
...  
Keyword(s):  
Respiratory Syncytial Virus ◽  
Antiviral Agent ◽  
Active Components ◽  
Sargassum Fusiforme ◽  
Antiviral Effects ◽  
Improve Life Expectancy ◽  
Rsv Infection ◽  
Syncytial Virus

Sargassum fusiforme, a plant used as a medicine and food, is regarded as a marine vegetable and health supplement to improve life expectancy. Here, we demonstrate that S. fusiforme extract (SFE) has antiviral effects against respiratory syncytial virus (RSV) in vitro and in vivo mouse model. Treatment of HEp2 cells with a non-cytotoxic concentration of SFE significantly reduced RSV replication, RSV-induced cell death, RSV gene transcription, RSV protein synthesis, and syncytium formation. Moreover, oral inoculation of SFE significantly improved RSV clearance from the lungs of BALB/c mice. Interestingly, the phenolic compounds eicosane, docosane, and tetracosane were identified as active components of SFE. Treatment with a non-cytotoxic concentration of these three components elicited similar antiviral effects against RSV infection as SFE in vitro. Together, these results suggest that SFE and its potential components are a promising natural antiviral agent candidate against RSV infection.

scholarly journals Global metabolomic and lipidomic analysis reveals the potential mechanisms of hemolysis effect of Ophiopogonin D and Ophiopogonin D' in vivo

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Huan-Hua Xu ◽  
Zhen-Hong Jiang ◽  
Cong-Shu Huang ◽  
Yu-Ting Sun ◽  
Long-Long Xu ◽  
...  
Keyword(s):  
Chemical Properties ◽  
Principal Component ◽  
Partial Least Square ◽  
Least Square ◽  
Practical Significance ◽  
Plasma Metabolites ◽  
Active Components ◽  
The Difference

Abstract Background OPD and OPD' are the two main active components of Ophiopogon japonicas in Shenmai injection (SMI). Being isomers of each other, they are supposed to have similar pharmacological activities, but the actual situation is complicated. The difference of hemolytic behavior between OPD and OPD' in vivo and in vitro was discovered and reported by our group for the first time. In vitro, only OPD' showed hemolysis reaction, while in vivo, both OPD and OPD' caused hemolysis. In vitro, the primary cause of hemolysis has been confirmed to be related to the difference between physical and chemical properties of OPD and OPD'. In vivo, although there is a possible explanation for this phenomenon, the one is that OPD is bio-transformed into OPD' or its analogues in vivo, the other one is that both OPD and OPD' were metabolized into more activated forms for hemolysis. However, the mechanism of hemolysis in vivo is still unclear, especially the existing literature are still difficult to explain why OPD shows the inconsistent hemolysis behavior in vivo and in vitro. Therefore, the study of hemolysis of OPD and OPD' in vivo is of great practical significance in response to the increase of adverse events of SMI. Methods Aiming at the hemolysis in vivo, this manuscript adopted untargeted metabolomics and lipidomics technology to preliminarily explore the changes of plasma metabolites and lipids of OPD- and OPD'-treated rats. Metabolomics and lipidomics analyses were performed on ultra-high performance liquid chromatography (UPLC) system tandem with different mass spectrometers (MS) and different columns respectively. Multivariate statistical approaches such as principal component analysis (PCA) and orthogonal partial least square-discriminant analysis (OPLS-DA) were applied to screen the differential metabolites and lipids. Results Both OPD and OPD' groups experienced hemolysis, Changes in endogenous differential metabolites and differential lipids, enrichment of differential metabolic pathways, and correlation analysis of differential metabolites and lipids all indicated that the causes of hemolysis by OPD and OPD' were closely related to the interference of phospholipid metabolism. Conclusions This study provided a comprehensive description of metabolomics and lipidomics changes between OPD- and OPD'-treated rats, it would add to the knowledge base of the field, which also provided scientific guidance for the subsequent mechanism research. However, the underlying mechanism require further research.

scholarly journals In vitro processing at the 3'-terminal region of pre-18S rRNA by a nucleolar endoribonuclease.

1990 ◽  
Vol 10 (8) ◽  
pp. 3868-3872 ◽  
Author(s):  
C M Shumard ◽  
C Torres ◽  
D C Eichler
Keyword(s):  
18S Rrna ◽  
Precise Determination ◽  
In Vivo Studies ◽  
Rrna Sequence ◽  
S1 Nuclease ◽  
In Vitro Processing ◽  
Rrna Maturation ◽  
A Site

In an investigation of the possible involvement of a highly purified nucleolar endoribonuclease in processing of pre-rRNA at the 3' end of the 18S rRNA sequence, an in vitro synthesized pre-18S rRNA transcript containing the 3' end region of 18S rRNA and the 5' region of the first internal transcribed spacer (ITS1) was used as a substrate for the enzyme. Cleavages generated by the nucleolar RNase were localized by S1 nuclease protection analysis and by the direct release of labeled rRNA products. Precise determination of the specificity of cleavage was achieved by RNA sequence analysis with end-labeled rRNA transcripts. These data demonstrated that the purified nucleolar RNase cleaved the pre-18S rRNA transcript at three specific sites relative to the 3' region of 18S rRNA. The first two sites included the mature 3'-end 18S rRNA sequence and a site approximately 55 nucleotides downstream of the 3'-end 18S rRNA sequence, both of which corresponded directly to recent results (Raziuddin, R. D. Little, T. Labella, and D. Schlessinger, Mol. Cell. Biol. 9:1667-1671, 1989) obtained with transfected mouse rDNA in hamster cells. The other cleavage occurred approximately 35 nucleotides upstream from the mature 3' end in the 18S rRNA sequence. The results from this study mimic the results obtained from in vivo studies for processing in the 3' region of pre-18S rRNA, supporting the proposed involvement of this nucleolar endoribonuclease in rRNA maturation.

Synthetic surfactant scavenges oxidants and protects against hyperoxic lung injury

1994 ◽  
Vol 77 (3) ◽  
pp. 1217-1223 ◽  
Author(s):  
A. J. Ghio ◽  
P. J. Fracica ◽  
S. L. Young ◽  
C. A. Piantadosi
Keyword(s):  
Thiobarbituric Acid ◽  
Cetyl Alcohol ◽  
Synthetic Surfactant ◽  
Active Components ◽  
Lung Weight ◽  
Hyperoxic Lung Injury ◽  
Surface Active ◽  
Artificial Surfactant

Injury and mortality after exposure to 100% oxygen can be diminished by surfactants that may operate by mechanisms other than those responsible for surface tension effects. We tested the hypotheses that 1) synthetic surfactant and its components function as antioxidants in vitro and 2) decrements in hyperoxic injury after treatment with a surfactant and its components are associated with decreases in oxidative stress to the lung. A synthetic surfactant (Exosurf) and its non-surface-active components tyloxapol and cetyl alcohol were incubated in an iron-containing hydroxyl radical-generating system to determine their abilities to prevent oxidation of deoxyribose. Doses of tyloxapol, cetyl alcohol, and artificial surfactant diminished the absorbance of thiobarbituric acid-reactive products of deoxyribose. Similarly, tyloxapol, cetyl alcohol, and the surfactant decreased hydroxylated products of salicylate in the same system. Rats were instilled intratracheally with saline, tyloxapol, tyloxapol plus cetyl alcohol, or artificial surfactant and immediately exposed to air or 100% oxygen. After 61 h of oxygen exposure, pleural fluid volume and wet-to-dry lung weight ratios were decreased in animals treated with surfactant and/or its components. There were also decrements in thiobarbituric acid-reactive products of lung tissue. In separate experiments, mean survival of saline-treated rats exposed to 100% oxygen was 67.3 +/- 8.1 h and > 96 h for rats given the surfactant or its components. We conclude that tyloxapol, cetyl alcohol, and Exosurf can function as antioxidants in vitro and their in vivo instillation is associated with reduction in measures of hyperoxic injury, oxidized tissue products, and mortality.

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