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1.
A. B. Więckowski G. P. Słowik J. A. Gąsiorek P. Gąsiorek F. Domka A. Perkowska 《Applied microbiology and biotechnology》1999,52(1):96-98
A comparison of iron-sulfur proteins obtained from Thiobacillus ferrooxidans was carried out. The microorganisms were grown on iron(II)- or sulfur-containing nutrients. In both cases different, broad
elctron paramagnetic resonance (EPR) lines, originating from an iron(III) compound, were detected. Additional EPR lines of
tetrahedral iron(III) and free radicals were observed. The UV spectra of these compounds also differ.
Received: 15 July 1998 / Received revision: 8 October 1998 / Accepted: 16 October 1998 相似文献
2.
3.
Immobilisation of Thiobacillus ferrooxidans cells on nickel alloy fibre for ferrous sulfate oxidation 总被引:4,自引:0,他引:4
The immobilisation of the iron-oxidising bacteria Thiobacillus ferrooxidans on nickel alloy fibre as support is described. This matrix showed promise for application in iron oxidation under strongly
acidic conditions. The influence on the colonisation process of T. ferrooxidans exerted by the initial pH of the medium and by temperature has also been studied. Results showed that immobilisation of T. ferrooxidans cells was affected by changes of temperature between 30 °C and 40 °C and in pH from 1.4 to 2.0.
Received: 25 January 2000 / Received version: 20 April 2000 / Accepted: 1 May 2000 相似文献
4.
Thiobacillus ferrooxidans was able to grow under anaerobic conditions on copper sulphide with ferric ion as the electron acceptor. The dissolution of
covellite under these conditions (68% after 35 days) was higher than values observed aerobically in cultures with similar
media composition and almost as high as under aerobic conditions without iron. From these results we propose a mechanism for
anaerobic bioleaching of covellite in the presence of ferric iron and speculate that it may occur in leach dumps where the
oxygen concentration is, as reported elsewhere, very low.
Received: 3 September 1996 / Received revision: 13 January 1997 / Accepted: 24 January 1997 相似文献
5.
Acidithiobacillus ferrooxidans cells can oxidize iron and sulfur and are key members of the microbial biomining communities that are exploited in the large-scale bioleaching of metal sulfide ores. Some minerals are recalcitrant to bioleaching due to the presence of other inhibitory materials in the ore bodies. Additives are intentionally included in processed metals to reduce environmental impacts and microbially influenced corrosion. We have previously reported a new aerobic corrosion mechanism where A. ferrooxidans cells combined with pyrite and chloride can oxidize low-grade stainless steel (SS304) with a thiosulfate-mediated mechanism. Here we explore process conditions and genetic engineering of the cells that enable corrosion of a higher grade steel (SS316). The addition of elemental sulfur and an increase in the cell loading resulted in a 74% increase in the corrosion of SS316 as compared to the initial sulfur- and cell-free control experiments containing only pyrite. The overexpression of the endogenous rus gene, which is involved in the cellular iron oxidation pathway, led to a further 85% increase in the corrosion of the steel in addition to the improvements made by changes to the process conditions. Thus, the modification of the culturing conditions and the use of rus-overexpressing cells led to a more than threefold increase in the corrosion of SS316 stainless steel, such that 15% of the metal coupons was dissolved in just 2 weeks. This study demonstrates how the engineering of cells and the optimization of their cultivation conditions can be used to discover conditions that lead to the corrosion of a complex metal target. 相似文献
6.
Thiobacillus ferrooxidans oxidized the sulphide minerals e.g., pyrite, pyrrhotite and copper concentrate under anaerobic conditions in the presence
of ferric ion as sole electron acceptor. Copper and iron were solubilized from sulphide ores by the sulphur (sulphide)-dependent
ferric-ion oxidoreductase activity. Treatment of resting cells of T. ferrooxidans with 0.5% phenol for 30 min completely destroyed the iron- and copper-solubilizing activity. The above treatment destroyed
the sulphur(sulphide)-dependent ferric-ion-reducing activity completely but did not affect the iron-oxidizing activity. The
results suggest that sulphur(sulphide)-dependent ferric-ion-reducing activity actively participates in the oxidation of sulphide
minerals under anaerobic conditions. The activity of sulphur(sulphide)-dependent ferric ion reduction in the solubilization
of iron and copper from the sulphide ores were also observed under aerobic conditions in presence of sodium azide (0.1 μmol),
which completely inhibits the iron-oxidizing activity.
Received: 23 May 1995/Received revision: 10 October 1995/Accepted: 16 October 1995 相似文献
7.
Jianyu Zhu Weifeng Jiao Qian Li Xueduan Liu Wenqing Qin Guanzhou Qiu Yuehua Hu Liyuan Chai 《Journal of industrial microbiology & biotechnology》2012,39(12):1833-1840
In order to better understand the bioleaching mechanism, expression of genes involved in energy conservation and community structure of free and attached acidophilic bacteria in chalcopyrite bioleaching were investigated. Using quantitative real-time PCR, we studied the expression of genes involved in energy conservation in free and attached Acidithiobacillus ferrooxidans during bioleaching of chalcopyrite. Sulfur oxidation genes of attached A. ferrooxidans were up-regulated while ferrous iron oxidation genes were down-regulated compared with free A. ferrooxidans in the solution. The up-regulation may be induced by elemental sulfur on the mineral surface. This conclusion was supported by the results of HPLC analysis. Sulfur-oxidizing Acidithiobacillus thiooxidans and ferrous-oxidizing Leptospirillum ferrooxidans were the members of the mixed culture in chalcopyrite bioleaching. Study of the community structure of free and attached bacteria showed that A. thiooxidans dominated the attached bacteria while L. ferrooxidans dominated the free bacteria. With respect to available energy sources during bioleaching of chalcopyrite, sulfur-oxidizers tend to be on the mineral surfaces whereas ferrous iron-oxidizers tend to be suspended in the aqueous phase. Taken together, these results indicate that the main role of attached acidophilic bacteria was to oxidize elemental sulfur and dissolution of chalcopyrite involved chiefly an indirect bioleaching mechanism. 相似文献
8.
Wide variations were found in the rate of chemical and microbiological leaching of iron from pyritic materials from various sources. Thiobacillus ferrooxidans accelerated leaching of iron from all of the pyritic materials tested in shake flask suspensions at loadings of 0.4% (wt/vol) pulp density. The most chemically reactive pyrites exhibited the fastest bioleaching rates. However, at 2.0% pulp density, a delay in onset of bioleaching occurred with two of the pyrites derived from coal sources. T. ferrooxidans was unable to oxidize the most chemically reactive pyrite at 2.0% pulp density. No inhibition of pyrite oxidation by T. ferrooxidans occurred with mineral pyrite at 2.0% pulp density. Experiments with the most chemically reactive pyrite indicated that the leachates from the material were not inhibitory to iron oxidation by T. ferrooxidans. 相似文献
9.
In the case of pyrite bioleaching by Leptospirillum ferrooxidans, an organism without sulfur-oxidizing capacity, besides the production of tetra- and pentathionate, a considerable accumulation of elemental sulfur occurred. A similar result was obtained for chemical oxidation assays with acidic, sterile iron(III) ion-containing solutions. In the case of Thiobacillus ferrooxidans, only slight amounts of elemental sulfur were detectable because of the organism's capacity to oxidize sulfur compounds. In the course of oxidative, chemical pyrite degradation under alkaline conditions, the accumulation of tetrathionate, trithionate, and thiosulfate occurred. The data indicate that thiosulfate, trithionate, tetrathionate, and disulfane-monosulfonic acid are key intermediate sulfur compounds in oxidative pyrite degradation. A novel (cyclic) leaching mechanism is proposed which basically is indirect. 相似文献
10.
Particle size effects in bioleaching of pyrite by acidophilic thermophile Sulfolobus metallicus (BC) 总被引:4,自引:0,他引:4
The effect of mineral particle size on the bioleaching of pyrite by the acidophilic thermophile Sulfolobus metallicus was investigated in a batch bioreactor. Decreasing the particle size from a mean diameter of 202 micron (size fraction: 150–180 micron)
to a mean diameter of 42.5 micron (size fraction: 25–45 micron) enhanced the bioleaching rate from 0.05 kg m−3 h−1 to 0.098 kg m−3 h−1. The particle size distribution of the mineral in this range did not influence the morphology and growth kinetics of the
cells. The values of specific growth rate (μ) and yield factor (Y) were 0.018–0.025 h−1 and 0.67 × 1011–1.45 × 1011 cells (g iron)−1, respectively. Decreasing the particle size of the mineral to a mean diameter of 6.40 micron (size fraction <25 micron) adversely
influenced the activity of the cells. The presence of fine particles apparently damaged the structure of the cells, resulting
in their inability to oxidise pyrite.
Received: 11 December 1998 / Accepted: 9 April 1999 相似文献
11.
The obligately autotrophic acidophile Thiobacillus ferrooxidans was grown on elemental sulfur in anaerobic batch cultures, using ferric iron as an electron acceptor. During anaerobic growth, ferric iron present in the growth media was quantitatively reduced to ferrous iron. The doubling time in anaerobic cultures was approximately 24 h. Anaerobic growth did not occur in the absence of elemental sulfur or ferric iron. During growth, a linear relationship existed between the concentration of ferrous iron accumulated in the cultures and the cell density. The results suggest that ferric iron may be an important electron acceptor for the oxidation of sulfur compounds in acidic environments. 相似文献
12.
The kinetics of continuous oxidation of ferrous iron by immobilized cells of Thiobacillus ferrooxidans was studied in a packed-bed bioreactor. Polyurethane foam biomass support particles were used as carriers for cell immobilization.
Effects of ferrous iron concentration and its volumetric loading on the kinetics of the reaction were investigated. Media
containing different concentrations of ferrous iron in the range 5–20 kg m-3 were tested. For each medium the kinetics of the reaction at different volumetric loadings of ferrous iron, at a constant
temperature of 30°C, were determined. With media containing 5 kg m-3 and 10 kg m-3 Fe2+, the fastest oxidation rates of 34.25 kg m-3 h-1 and 32 kg m-3 h-1 were achieved at a dilution rate of around 6 h-1, which represents a residence time of 10 min. Employing a higher concentration of ferrous iron (20 kg m-3) in the medium resulted in lower oxidation rates, with a maximum value of 10 kg m-3 h-1, indicating an inhibitory effect of ferrous iron on growth and activity of T. ferrooxidans. The reliable performance of the bioreactor during the course of the experiments confirmed the suitability of polyurethane
foam biomass support particles as carriers for T. ferrooxidans immobilization.
Received: 5 December 1995/Received revision: 21 April 1996/Accepted: 29 April 1996 相似文献
13.
Norris PR Davis-Belmar CS Brown CF Calvo-Bado LA 《Extremophiles : life under extreme conditions》2011,15(2):155-163
Some novel actinobacteria from geothermal environments were shown to grow autotrophically with sulfur as an energy source.
These bacteria have not been formally named and are referred to here as “Acidithiomicrobium” species, as the first of the acidophilic actinobacteria observed to grow on sulfur. They are related to Acidimicrobium ferrooxidans with which they share a capacity for ferrous iron oxidation. Ribulose bisphosphate carboxylase/oxygenase (RuBisCO) is active
in CO2 fixation by Acidimicrobium ferrooxidans, which appears to have acquired its RuBisCO-encoding genes from the proteobacterium Acidithiobacillus ferrooxidans or its ancestor. This lateral transfer of RuBisCO genes between a proteobacterium and an actinobacterium would add to those
noted previously among proteobacteria, between proteobacteria and cyanobacteria and between proteobacteria and plastids. “Acidithiomicrobium” has RuBisCO-encoding genes which are most closely related to those of Acidimicrobium ferrooxidans and Acidithiobacillus ferrooxidans, and has additional RuBisCO genes of a different lineage. 16S rRNA gene sequences from “Acidithiomicrobium” species dominated clone banks of the genes extracted from mixed cultures of moderate thermophiles growing on copper sulfide
and polymetallic sulfide ores in ore leaching columns. 相似文献
14.
Several cultures ofThiobacillus ferrooxidans were purified by isolation of single colonies and simple physiological and biochemical properties of the purified cultures,
such as colony morphology, kinetics of ferrous ion oxidation, growth on elemental sulfur and thiosulfate, oxidation of ferrous
ion by growing cells in the presence of organic compounds and metal ions, were examined. These properties may be used to characterize
a range ofT. ferrooxidans isolates and for numerical taxonomy.
This work was part of a project sponsored by theHindustan Copper Limited, Calcutta. The authors are thankful to Dr. P.N. Kundu and Dr. S. Duttagupta for their help in the initiation of this work. 相似文献
15.
The ferrous iron oxidation kinetics of Thiobacillus ferrooxidans in batch cultures was examined, using on-line off-gas analyses to measure the oxygen and carbon dioxide consumption rates
continuously. A cell suspension from continuous cultures at steady state was used as the inoculum. It was observed that a
dynamic phase occurred in the initial phase of the experiment. In this phase the bacterial ferrous iron oxidation and growth
were uncoupled. After about 16 h the bacteria were adapted and achieved a pseudo-steady state, in which the specific growth
rate and oxygen consumption rate were coupled and their relationship was described by the Pirt equation. In pseudo-steady
state, the growth and oxidation kinetics were accurately described by the rate equation for competitive product inhibition.
Bacterial substrate consumption is regarded as the primary process, which is described by the equation for competitive product
inhibition. Subsequently the kinetic equation for the specific growth rate, μ, is derived by applying the Pirt equation for bacterial substrate consumption and growth. The maximum specific growth rate,
μ
max, measured in the batch culture agrees with the dilution rate at which washout occurs in continuous cultures. The maximum
oxygen consumption rate, q
O2,max, of the cell suspension in the batch culture was determined by respiration measurements in a biological oxygen monitor at
excess ferrous iron, and showed changes of up to 20% during the course of the experiment. The kinetic constants determined
in the batch culture slightly differ from those in continuous cultures, such that, at equal ferric to ferrous iron concentration
ratios, biomass-specific rates are up to 1.3 times higher in continuous cultures.
Received: 8 February 1999 / Accepted: 17 February 1999 相似文献
16.
G. Huerta B. Escobar J. Rubio R. Badilla-Ohlbaum 《World journal of microbiology & biotechnology》1995,11(5):599-600
Oxidation of Fe(II) iron and bioleaching of pyrite and chalcopyrite by Thiobacillus ferrooxidans was adversely affected by isopropylxanthate, a flotation agent, and by LIX 984, a solvent-extraction agent, each at 1 g/l. The reagents/l were adsorbed on the bacterial surface, decreasing the bacteria's development and preventing biooxidation. Both reagents inhibited the bioleaching of pyrite and LIX 984 also inhibited the bioleaching of chalcopyrite. 相似文献
17.
Exocellular polysaccharides were extracted from Thiobacillus ferrooxidans cells grown in the presence of iron. Cells without these compounds could not adhere to covellite. The loss of the layer of
exocellular polysaccharides also affected the direct mechanism of bioleaching of covellite in a negative way. This ability
to attach to and leach covellite was restored within a few hours when exopolymeric material was produced again. The addition
of exocellular compounds to cells stripped of exocellular polymers also restored their ability to the same level as that of
untreated cells. Thiobacillus thiooxidans was not able to attach to and leach covellite even when exocellular compounds from Thiobacillus ferrooxidans were added.
Received 2 June 1998/ Accepted in revised form 8 January 1999 相似文献
18.
The oxidation of a pure pyrite by Thiobacillus ferrooxidans is not really a constant phenomenon; it must be considered to be more like a succession of different steps which need characterization. Electrochemical studies using a combination of a platinum electrode and a specific pyrite electrode (packed-ground-pyrite electrode) revealed four steps in the bioleaching process. Each step can be identified by the electrochemical behavior (redox potentials) of pyrite, which in turn can be related to chemical (leachate content), bacterial (growth), and physical (corrosion patterns) parameters of the leaching process. A comparison of the oxidation rates of iron and sulfur indicated the nonstoichiometric bacterial oxidation of a pure pyrite in which superficial phenomena, aqueous oxidation, and deep crystal dissolution are successively involved. 相似文献
19.
Acidithiobacillus thiooxidans secretome containing a newly described lipoprotein Licanantase enhances chalcopyrite bioleaching rate 总被引:1,自引:0,他引:1
The nature of the mineral–bacteria interphase where electron and mass transfer processes occur is a key element of the bioleaching
processes of sulfide minerals. This interphase is composed of proteins, metabolites, and other compounds embedded in extracellular
polymeric substances mainly consisting of sugars and lipids (Gehrke et al., Appl Environ Microbiol 64(7):2743–2747, 1998). On this respect, despite Acidithiobacilli—a ubiquitous bacterial genera in bioleaching processes (Rawlings, Microb Cell
Fact 4(1):13, 2005)—has long been recognized as secreting bacteria (Jones and Starkey, J Bacteriol 82:788–789, 1961; Schaeffer and Umbreit, J Bacteriol 85:492–493, 1963), few studies have been carried out in order to clarify the nature and the role of the secreted protein component: the secretome.
This work characterizes for the first time the sulfur (meta)secretome of Acidithiobacillus thiooxidans strain DSM 17318 in pure and mixed cultures with Acidithiobacillus ferrooxidans DSM 16786, identifying the major component of these secreted fractions as a single lipoprotein named here as Licanantase.
Bioleaching assays with the addition of Licanantase-enriched concentrated secretome fractions show that this newly found lipoprotein
as an active protein additive exerts an increasing effect on chalcopyrite bioleaching rate. 相似文献
20.
Qiu Guan Zhou Fu Bo Zhou Hong Bo Liu Xi Gao Jian Liu Fei Fei Chen Xin Hua 《World journal of microbiology & biotechnology》2007,23(9):1217-1225
A moderately thermophilic and acidophilic sulfur-oxidizing bacterium named S2, was isolated from coal heap drainage. The bacterium was motile, Gram-negative, rod-shaped, measured 0.4 to 0.6 by 1 to 2 μm,
and grew optimally at 42–45°C and an initial pH of 2.5. The strain S2 grew autotrophically by using elemental sulfur, sodium thiosulfate and potassium tetrathionate as energy sources. The strain
did not use organic matter and inorganic minerals including ferrous sulfate, pyrite and chalcopyrite as energy sources. The
morphological, biochemical, physiological characterization and analysis based on 16S rRNA gene sequence indicated that the
strain S2 is most closely related to Acidithiobacillus caldus (>99% similarity in gene sequence). The combination of the strain S2 with Leptospirillum ferriphilum or Acidithiobacillus ferrooxidans in chalcopyrite bioleaching improved the copper-leaching efficiency. Scanning electron microscope (SEM) analysis revealed
that the chalcopyrite surface in a mixed culture of Leptospirillum ferriphilum and Acidithiobacillus caldus was heavily etched. The energy dispersive X-ray (EDX) analysis indicated that Acidithiobacillus caldus has the potential role to enhance the recovery of copper from chalcopyrite by oxidizing the sulfur formed during the bioleaching
progress. 相似文献