| dissimilatory ferrous iron oxidation at a low ph: a novel trait identified in the bacterial subclass rubrobacteridae. | a novel iron-oxidizing acidophilic actinobacterium was isolated from spoil material at an abandoned copper mine. phylogenetic analysis placed the isolate within the rubrobacteridae subclass of the actinobacteria. its optimum temperature and ph for growth are 30-35 degrees c and ph 3.0, respectively. although it could catalyze the dissimilatory oxidation of ferrous iron, growth yields declined progressively in media containing ferrous iron concentrations >100 microm. the isolate, pa33, did not gr ... | 2008 | 18803673 |
| [gene function and microbial community structure in sulfide minerals bioleaching system based on microarray analysis]. | biohydrometallergy technology received more and more attention because of its simple process, low cost and kind to environment, especially in dealing with low-grade and complex minerals. however, it is difficult to optimize microorganism species and process parameters in bioleaching procedure because of the lack of suitable bacteria and quantitative analysis methods at micro-level for bioleaching system. this has resulted in the low efficiency and poor yield of the target metal in bioleaching. w ... | 2008 | 18807978 |
| the primary structure and characteristics of the isafe600, an insertion sequence from acidithiobacillus ferrooxidans strains. | a new is-like element (604 bp) was revealed in the genome of several acidithiobacillus ferrooxidans strains isolated from diverse biotopes. it includes 26-bp imperfectly matched terminal inverted repeats (tirs), similar in structure to the tirs of isafel insertion element. the 60-bp dna fragment adjacent to the right tir (tirr) exhibits pronounced homology with the similarly located dna fragments in isafel and ist445, as well as with the internal fragment of isafel encoding the transposase gene ... | 2008 | 18825980 |
| effects of l-cysteine on ni-cu sulfide and marmatite bioleaching by acidithiobacillus caldus. | the effect of l-cysteine in different concentrations on the bioleaching of ni-cu sulfide and marmatite were studied with a moderately thermophilic, sulfur-oxidizing bacterium, strain of acidithiobacillus caldus. x-ray diffraction (xrd) observations showed the change of bioleached solid residues and the effect of l-cysteine on the surface charges of minerals. it was found that adding certain amounts of l-cysteine to the leaching system of ni-cu sulfide largely enhanced the leaching rate, while l- ... | 2009 | 18829304 |
| energetic problems faced by micro-organisms growing or surviving on parsimonious energy sources and at acidic ph: i. acidithiobacillus ferrooxidans as a paradigm. | the mitochondrial paradigm for a chemiosmotic energy transduction mechanism requires frequently misunderstood modifications for application to microbes growing and surviving at acidic ph values and/or with relatively weak reductants as energy sources. here the bioenergetics of the iron oxidiser acidithiobacillus ferrooxidans are reviewed and analysed so as to develop the general bioenergetic principles for understanding organisms that grow under these conditions. extension of the principles outl ... | 2008 | 18835548 |
| inhibition of microbial concrete corrosion by acidithiobacillus thiooxidans with functionalised zeolite-a coating. | the inhibition of the corrosive action of acidithiobacillus thiooxidans on concrete specimens coated by functionalised zeolite-a containing 14% zinc and 5% silver by weight was studied. uncoated concrete specimens, epoxy-coated concrete specimens (ep), and functionalised zeolite-a coated concrete specimens with epoxy to zeolite weight ratios of 3:1 (z1), 2:2 (z2) and 1:3 (z3) were studied. specimens were characterised by x-ray powder diffraction and field emission scanning electron microscopy fo ... | 2009 | 18846450 |
| glu43 is an essential residue for coordinating the [fe2s2] cluster of iscr from acidithiobacillus ferrooxidans. | the iron-sulfur cluster regulator (iscr) was reported to be a repressor of the iscrsua operon. in vitro transcription reactions revealed that the iscr had a repression effect on the iscr promoter. the iscr contains a [fe2s2] cluster per each monomer, and three highly conserved cysteines were identified to ligate the [fe2s2] cluster. it was proposed that a non-cysteine residue might be the fourth ligand for the [fe2s2] cluster. in this study, using site-directed mutagenesis, glu43 was found to be ... | 2008 | 18955052 |
| expression, purification, and characterization of iron-sulfur cluster assembly regulator iscr from acidithiobacillus ferrooxidans. | iscr (iron-sulfur cluster regulator) has been reported to be a repressor of the iscrsua operon, and in vitro transcription reactions have revealed that iscr has a repressive effect on the iscr promoter in the case of [fe(2)s(2)] cluster loading. in the present study, the iscr gene from a. ferrooxidans atcc 23270 was cloned and successfully expressed in escherichia coli, and then purified by one-step affinity chromatography to homogeneity. the molecular mass of the iscr was 18 kda by sds-page. th ... | 2008 | 18955818 |
| microbial iron management mechanisms in extremely acidic environments: comparative genomics evidence for diversity and versatility. | iron is an essential nutrient but can be toxic at high intracellular concentrations and organisms have evolved tightly regulated mechanisms for iron uptake and homeostasis. information on iron management mechanisms is available for organisms living at circumneutral ph. however, very little is known about how acidophilic bacteria, especially those used for industrial copper bioleaching, cope with environmental iron loads that can be 1018 times the concentration found in ph neutral environments. t ... | 2008 | 19025650 |
| technological assessment of a mining-waste dump at the dexing copper mine, china, for possible conversion to an in situ bioleaching operation. | in order to extract copper metal from the waste dump of dexing copper mine and resolve the environmental problems caused by acidic water and heavy metals, a dump bioleaching plant was designed based on a series of experimental investigations. the investigation shown that the low-grade of the dump, refractoriness of chalcopyrite, leakage of pad, small acidithiobacillus population and low dump permeability are the main factors that contribute to the challenges faced by the plant. stability of the ... | 2009 | 19036579 |
| application of real-time pcr to monitor population dynamics of defined mixed cultures of moderate thermophiles involved in bioleaching of chalcopyrite. | to compare oxidative dissolution rates of chalcopyrite by different consortia of moderately thermophilic acidophiles, various defined mixed cultures of three bacteria acidithiobacillus caldus s2, leptospirillum ferriphilum ysk, and sulfobacillus sp. ln and one archaeon ferroplasma thermophilum l1 were studied in batch shake flask cultures incubated at 45 degrees c. chalcopyrite dissolution was determined by measuring variations of soluble copper, ferric iron, and ph. microbial population dynamic ... | 2009 | 19039582 |
| regulation of co2 fixation gene expression in acidithiobacillus ferrooxidans atcc 23270 by lix984n shock. | acidithiobacillus ferrooxidans atcc 23270 is an important model organism for bioleaching and bioremediation studies owing to its diverse metabolic capabilities, whereas lix984n is a widely used extractant. little is known about the response of cbb genes in a. ferrooxidans to lix984n shock. thus, to elucidate the response of the co2 fixation genes in a. ferrooxidans atcc 23270 to the addition of lix984n, the gene expression of cbb genes was examined using a real-time pcr. although a natural incre ... | 2008 | 19047816 |
| comparative genomic analysis of carbon and nitrogen assimilation mechanisms in three indigenous bioleaching bacteria: predictions and validations. | carbon and nitrogen fixation are essential pathways for autotrophic bacteria living in extreme environments. these bacteria can use carbon dioxide directly from the air as their sole carbon source and can use different sources of nitrogen such as ammonia, nitrate, nitrite, or even nitrogen from the air. to have a better understanding of how these processes occur and to determine how we can make them more efficient, a comparative genomic analysis of three bioleaching bacteria isolated from mine s ... | 2008 | 19055775 |
| microbial thiosulphate reaction arrays: the interactive roles of fe(iii), o2 and microbial strain on disproportionation and oxidation pathways. | in this work, we experimentally evaluate ph and so4(2-) dynamics associated with abiotic and microbial s2o3(2-) oxidation under varying [o2], [fe(iii)] and microbial strain/consortia (two pure strains, acidithiobacillus ferrooxidans, acidithiobacillus thiooxidans, their consortia, and two enrichments from an acidic environmental system, moose lake 2002 and moose lake 2003). results of the batch experiments demonstrate highly active microbial processing of s2o3(2-) while abiotic controls under id ... | 2008 | 19076637 |
| acidithiobacillus ferrooxidans metabolism: from genome sequence to industrial applications. | acidithiobacillus ferrooxidans is a major participant in consortia of microorganisms used for the industrial recovery of copper (bioleaching or biomining). it is a chemolithoautrophic, gamma-proteobacterium using energy from the oxidation of iron- and sulfur-containing minerals for growth. it thrives at extremely low ph (ph 1-2) and fixes both carbon and nitrogen from the atmosphere. it solubilizes copper and other metals from rocks and plays an important role in nutrient and metal biogeochemica ... | 2008 | 19077236 |
| investigation of elemental sulfur speciation transformation mediated by acidithiobacillus ferrooxidans. | the speciation transformation of elemental sulfur mediated by the leaching bacterium acidithiobacillus ferrooxidans was investigated using an integrated approach including scanning electron microscopy, transmission electron microscopy, fourier transform infrared spectroscopy, energy dispersive x-ray spectroscopy, and x-ray absorption near edge spectroscopy (xanes). our results showed that when grown on elemental sulfur powder, at. ferrooxidans atcc23270 cells were first attached to sulfur partic ... | 2009 | 19085035 |
| a stoichiometric model of acidithiobacillus ferrooxidans atcc 23270 for metabolic flux analysis. | a stoichiometric model of acidithiobacillus ferrooxidans based on the sequenced genome from strain atcc 23270 is derived and parameterized using genome/pathway databases. the model describes the main aspects of catabolism and anabolism. by the construction and utilization of the mathematical determination of the network, metabolic flux analysis is performed for such a bacterium for the first time and results are successfully verified by comparison to literature values. this first metabolic model ... | 2009 | 19090483 |
| soft-particle model analysis of effect of lps on electrophoretic softness of acidithiobacillus ferrooxidans grown in presence of different metal ions. | the effect of surface lipopolysaccharides (lps) on the electrophoretic softness and fixed charge density in the ion-penetrable layer of acidithiobacillus ferrooxidans cells grown in presence of copper or arsenic ions have been discussed. the electrophoretic mobility data were analyzed using the soft-particle electrophoresis theory. cell surface potentials of all the strains based on soft-particle theory were lower than those estimated using the conventional smoluchowski theory. exposure to metal ... | 2009 | 19101128 |
| metals tolerance in moderately thermophilic isolates from a spent copper sulfide heap, closely related to acidithiobacillus caldus, acidimicrobium ferrooxidans and sulfobacillus thermosulfidooxidans. | selective enrichments enabled the recovery of moderately thermophilic isolates with copper bioleaching ability from a spent copper sulfide heap. phylogenetic and physiological characterization revealed that the isolates were closely related to sulfobacillus thermosulfidooxidans, acidithiobacillus caldus and acidimicrobium ferrooxidans. while isolates exhibited similar physiological characteristics to their corresponding type strains, in general they displayed similar or greater tolerance of high ... | 2009 | 19104861 |
| solid2: an antibody array-based life-detector instrument in a mars drilling simulation experiment (marte). | a field prototype of an antibody array-based life-detector instrument, signs of life detector (solid2), has been tested in a mars drilling mission simulation called marte (mars astrobiology research and technology experiment). as one of the analytical instruments on the marte robotic drilling rig, solid2 performed automatic sample processing and analysis of ground core samples (0.5 g) with protein microarrays that contained 157 different antibodies. core samples from different depths (down to 5. ... | 2008 | 19105755 |
| influence of chloride and sulfate on formation of akaganéite and schwertmannite through ferrous biooxidation by acidithiobacillus ferrooxidans cells. | iron (oxyhydr)oxides play important roles in the fixation of toxic elements and also in the distribution of nutrients for plants in soils. akaganéite and schwertmannite, as the iron oxyhydroxides having an analogous tunnel structure, have been widely recognized in fe-rich environments. the objective of this study was to examine the formation of akaganéite/ schwertmannite via biooxidation of 0.1 m of ferrous solution containing only cl-, so4(2-) or both the anions with a cl-/so4(2-) mole ratio of ... | 2008 | 19192781 |
| a two-stage process for simultaneous thermophilic sludge digestion, pathogen control and metal leaching. | a consortium of aerobic sulphur oxidizing microorganisms native to municipal sewage sludge has been developed that is capable of reducing the ph of sludge from 7.0 to 2.0 under mild-thermophilic (45 degrees c) temperatures. this mild-thermophilic, acidophilic acclimatized consortium has then been used to develop a thermophilic acidophilic culture capable of reducing the ph of municipal sewage sludge from 7.0 to 4.8 at 60 degrees c. furthermore, these two cultures have been used to develop a nove ... | 2009 | 19213462 |
| characterization and reconstitute of a [fe4s4] adenosine 5'-phosphosulfate reductase from acidithiobacillus ferrooxidans. | adenosine 5'-phosphosulfate (aps) reductase is a key enzyme involved in the pathways of sulfate reduction and sulfide oxidation in the biological sulfur cycle. in this study, the gene of aps reductase from acidithiobacillus ferrooxidans was cloned and expressed in escherichia coli, the soluble protein was purified by one-step affinity chromatography to apparent homogeneity. the molecular mass of the recombinant aps reductase was determined to be 28 kda using sds-page. according to optical and ep ... | 2009 | 19225840 |
| an xps analytical approach for elucidating the microbially mediated enargite oxidative dissolution. | in this work, the microbe-mediated oxidative dissolution of enargite surfaces (cu(3)ass(4)) was studied on powdered samples exposed to 9k nutrient solution (ph 2.3) inoculated by acidithiobacillus ferrooxidans initially adapted to arsenopyrite. these conditions simulate the acid mine environment. the redox potential of the inoculated solutions increased up to +0.72 v vs normal hydrogen electrode (nhe), indicating the increase of the fe(3+) to fe(2+) ratio, and correspondingly the ph decreased to ... | 2009 | 19229526 |
| [a two-stage technology for bacterial and chemical leaching of copper-zinc raw materials by fe3+ ions with their subsequent regeneration by chemolithotrophic bacteria]. | a two-stage technology for bacterial and chemical leaching of nonferrous metals in a specifically designed laboratory unit has been proposed. at the first stage of leaching, ferric iron formed during the second stage of oxidation of fe2+ ions by mesophilic chemolithotrophic microorganisms was used. the optimal parameters of the first stage of the process (flow rate, temperature, and the process duration) were 2 l/h, 75 degrees c, and 2 h, respectively. the results of testing of the two-stage tec ... | 2009 | 19235511 |
| bacterial communities of tyre monofill sites: growth on tyre shreds and leachate. | to investigate bacterial communities of tyre monofill sites, colonization of tyre material by bacteria and the effect of tyre leachate on bacteria. | 2009 | 19239530 |
| importance of different physiological groups of iron reducing microorganisms in an acidic mining lake remediation experiment. | iron- and sulfate-reducing microorganisms play an important role for alkalinity-generating processes in mining lakes with low ph. in the acidic mining lake 111 in lusatia, germany, a passive in situ remediation method was tested in a large scale experiment, in which microbial iron and sulfate reduction are stimulated by addition of carbokalk (a mixture of the nonsugar compounds of sugar beets and lime) and straw. the treated surface sediment consisted of three layers of different ph and geochemi ... | 2009 | 19277769 |
| dissolution kinetics of spent petroleum catalyst using sulfur oxidizing acidophilic microorganisms. | bioleaching studies of spent petroleum catalyst were carried out using sulfur oxidizing, acidithiobacillus species. leaching studies were carried out in two-stage, in the first stage bacteria were grown and culture filtrate was used in the second stage for leaching purpose. xrd analysis of spent petroleum catalyst showed oxides of v, fe and al and sulfides of mo and ni. the leaching kinetics followed dual rate, initial faster followed by slower rate and equilibrium could be achieved within 7 day ... | 2009 | 19286311 |
| electron transfer from cytochrome c to cupredoxins. | electron transfer (et) through and between proteins is a fundamental biological process. the activation energy for an et reaction depends upon the gibbs energy change upon et (deltag(0)) and the reorganization energy. here, we characterized et from pseudomonas aeruginosa cytochrome c(551) (pa) and its designed mutants to cupredoxins, silene pratensis plastocyanin (pc) and acidithiobacillus ferrooxidans rusticyanin (rc), through measurement of pseudo-first-order et rate constants (k(obs)). the in ... | 2009 | 19294434 |
| investigation and optimization of a passively operated compost-based system for remediation of acidic, highly iron- and sulfate-rich industrial waste water. | a passively operated multi-stage bioremediation system utilizing composted agricultural waste products and an artificial wetland system was found to be effective for purification of acidic, iron- and sulfate-rich waste water derived from titanium mineral processing. the main microbial players involved in the remediation system processes and the dynamics were investigated; mineral processing waste water-filled sludge dams possessed stable microbial communities that included acidithiobacillus, des ... | 2009 | 19297003 |
| bioleaching of heavy metals from sewage sludge: a review. | during the treatment of sewage, a huge volume of sludge is generated, which is disposed of on land as soil fertilizer/conditioner due to the presence of nitrogen, phosphorus, potassium and other nutrients. however, the presence of toxic heavy metals and other toxic compounds in the sludge restricts its use as a fertilizer. over the years, bioleaching has been developed as an environmentally friendly and cost-effective technology for the removal of heavy metals from the sludge. the present paper ... | 2009 | 19303195 |
| microbial communities in acid mine drainage and their interaction with pyrite surface. | microbes such as acidithiobacillus ferrooxidans and leptospirillum ferrooxidans have been investigated a lot, because of their important role in acid mine drainage (amd) generation. in this article, the composition of microbial communities in two amd samples was studied. a culture-independent 16s rdna-based cloning approach, restriction fragment length polymorphism has been used. the interaction between microbes and natural pyrite specimen surface was researched by scanning electrode microscopy ... | 2009 | 19319595 |
| expression, purification and molecular structure modeling of thioredoxin (trx) and thioredoxin reductase (trxr) from acidithiobacillus ferrooxidans. | the thioredoxin system consists of thioredoxin (trx), thioredoxin reductase (trxr) and nadph, which plays several key roles in maintaining the redox environment of the cell. in acidithiobacillus ferrooxidans, thioredoxin system may play important functions in the activity regulation of periplasmic proteins and energy metabolism. here, we cloned thioredoxin (trx) and thioredoxin reductase (trxr) genes from acidithiobacillus ferrooxidans, and expressed the genes in escherichia coli. his-trx and hi ... | 2009 | 19319598 |
| enhanced biofiltration using cell attachment promotors. | h2s polluted airstreams were treated in two biotrickling filter columns packed with polyurethane (pu) foam cubes, one with cubes coated with a solution of 25 mg/l of polyethyleneimine (pei, coated reactor) and the other containing just plain pu cubes (uncoated reactor) at empty bed residence times (ebrt) ranging from 6 to 60 s. and inlet h2s concentrations ranging from 30 to 235 ppm, (overall loads of up to 44 gh2s/m3bed/h), with overall removal efficiencies (re) in the range of 90-100% over 125 ... | 2009 | 19320156 |
| ferrous iron oxidation and rusticyanin in halotolerant, acidophilic 'thiobacillus prosperus'. | the halotolerant acidophile 'thiobacillus prosperus' was shown to require chloride for growth. with ferrous iron as substrate, growth occurred at a rate similar to that of the well-studied acidophile acidithiobacillus ferrooxidans. previously, the salt (nacl) requirement of 't. prosperus' was not clear and its growth on ferrous iron was described as poor. a subtractive hybridization of cdnas from ferrous-iron-grown and sulfur-grown 't. prosperus' strain v6 led to identification of a cluster of g ... | 2009 | 19332831 |
| comparison of bioleaching behaviors of different compositional sphalerite using leptospirillum ferriphilum, acidithiobacillus ferrooxidans and acidithiobacillus caldus. | two sphalerite samples with different iron/sulphur (fe/s) ratios, shuikousan ore (fe/s 0.2) and dachang ore (fe/s 0.52), were processed using three microbial species, leptospirillum ferriphilum, acidithiobacillus ferrooxidans and acidithiobacillus caldus. following 20 days of bioleaching in shake flask cultures, a higher zinc (zn) extraction (96%) was achieved with shuikousan ore than with dachange ore (72%). the extraction efficiency increased when elemental s was added to dachang ore to attain ... | 2009 | 19333635 |
| [response of genes for synthesizing the magnetic of acidithiobacillus ferrooxidans to different concentration of fe2+ stress]. | acidithiobacillus ferrooxidans is able to synthesize intra-cellular electron-dense magnetite, which formed by bcm method in acidithiobacillus ferrooxidans. the whole genome of the type strain acidithiobacillus ferrooxidans atcc 23270 was analyzed by bioinformatics and some homolog genes of functional ones in magnetotactic bacteria were available. this study analyzed the different concentration of fe2+ stress response of mpsa, maga, thy and mamb gene by using real-time pcr analysis. temporal gene ... | 2009 | 19441229 |
| real-time pcr analysis of the heat-shock response of acidithiobacillus ferrooxidans atcc 23270. | as one of the most important bioleaching bacterial species, acidithiobacillus ferrooxidans is subjected to different kinds of environmental stress such as temperature changes, presence of some toxic heavy metals or ph changes, which normally take place in bioleaching operations and may affect the activity of the bacteria. to obtain further knowledge of the protective mechanisms employed by a. ferrooxidans in response to elevated growth temperature, temporal gene expression profiles were examined ... | 2009 | 19445839 |
| [pyrite oxidation by the diverse microorganisms]. | | 2009 | 19449732 |
| [acidophilic chemolithotrophic microorganisms: growth and pyrite oxidation ]. | | 2009 | 19449733 |
| fractionation behavior of heavy metals in soil during bioleaching with acidithiobacillus thiooxidans. | the effects of bioleaching on the fractionation of soil heavy metals were investigated in this study. bioleaching of heavy metals from contaminated soil was carried out in shake flask experiments. acidophilic sulfur oxidizing bacteria acidithiobacillus thiooxidans isolated from soil was used for bioleaching. bioleaching resulted in removal of heavy metals at higher levels. variations in the binding forms of heavy metals before, during and after bioleaching were evaluated. it was noticed that bio ... | 2009 | 19464109 |
| comparative genomic analysis of acidithiobacillus ferrooxidans strains using the a. ferrooxidans atcc 23270 whole-genome oligonucleotide microarray. | acidithiobacillus ferrooxidans is an important microorganism used in biomining operations for metal recovery. whole-genomic diversity analysis based on the oligonucleotide microarray was used to analyze the gene content of 12 strains of a. ferrooxidans purified from various mining areas in china. among the 3100 open reading frames (orfs) on the slides, 1235 orfs were absent in at least 1 strain of bacteria and 1385 orfs were conserved in all strains. the hybridization results showed that these s ... | 2009 | 19483787 |
| ferrous iron production mediated by tetrathionate hydrolase in tetrathionate-, sulfur-, and iron-grown acidithiobacillus ferrooxidans atcc 23270 cells. | when tetrathionate-grown acidithiobacillus ferrooxidans atcc 23270 cells were incubated with ferric ions and tetrathionate at ph 3.0, ferrous ions were produced enzymatically. fe(3+)-reductase, which catalyzes fe(3+) reduction with tetrathionate, was purified to homogeneity not only from tetrathionate-grown, but also from sulfur- and iron-grown a. ferrooxidans atcc 23270 cells. the results for apparent molecular weight measured by sds-page (52.3 kd) and the n-terminal amino acid sequences of the ... | 2009 | 19502725 |
| selection and evaluation of reference genes for improved interrogation of microbial transcriptomes: case study with the extremophile acidithiobacillus ferrooxidans. | normalization is a prerequisite for accurate real time pcr (qpcr) expression analysis and for the validation of microarray profiling data in microbial systems. the choice and use of reference genes that are stably expressed across samples, experimental conditions and designs is a key consideration for the accurate interpretation of gene expression data. | 2009 | 19555508 |
| an acid-tolerant heterotrophic microorganism role in improving tannery sludge bioleaching conducted in successive multibatch reaction systems. | the bioleaching technique with acidithiobacillus species has been shown to be an efficient and cost-effective means in removing heavy metals from tannery sludge. however, tannery sludge dissolved organic matter (dom) is toxic to acidithiobacillus species and results in decreasing the efficiency of cr removal from sludge. here we report the role of an acid-tolerant dom-degrading heterotrophic microorganism p. spartinae d13 successfully isolated from local tannery sludge in improving activities of ... | 2009 | 19569344 |
| [characteristics of microspheres formed with bacterial genomic dna and plasmid templates in the process of polymerase chain reaction]. | | 2009 | 19580161 |
| ferrous iron oxidation by foam immobilized acidithiobacillus ferrooxidans: experiments and modeling. | ferrous iron bio-oxidation by acidithiobacillus ferrooxidans immobilized on polyurethane foam was investigated. cells were immobilized on foams by placing them in a growth environment and fully bacterially activated polyurethane foams (bapufs) were prepared by serial subculturing in batches with partially bacterially activated foam (pbapufs). the dependence of foam density on cell immobilization process, the effect of ph and bapuf loading on ferrous oxidation were studied to choose operating par ... | 2009 | 19610075 |
| draft genome sequence of the extremely acidophilic bacterium acidithiobacillus caldus atcc 51756 reveals metabolic versatility in the genus acidithiobacillus. | acidithiobacillus caldus is an extremely acidophilic, moderately thermophilic, chemolithoautotrophic gammaproteobacterium that derives energy from the oxidation of sulfur and reduced inorganic sulfur compounds. here we present the draft genome sequence of acidithiobacillus caldus atcc 51756 (the type strain of the species), which has permitted the prediction of genes for survival in extremely acidic environments, including genes for sulfur oxidation and nutrient assimilation. | 2009 | 19617360 |
| the inhibitory effect of antimicrobial zeolite on the biofilm of acidithiobacillus thiooxidans. | the inhibitory effect of antimicrobial zeolite coated concrete specimens (z2) against acidithiobacillus thiooxidans was studied by measuring biomass dry cell weight (dcw), biological sulphate generation, and oxygen uptake rates (ours). uncoated (uc), and blank zeolite coated without antimicrobial agent (zc) concrete specimens were used as controls. the study was undertaken by exposing inoculated basal nutrient medium (bnm) to the various specimens. the coating material was prepared by mixing zeo ... | 2010 | 19618279 |
| preliminary x-ray crystallographic analysis of sulfide:quinone oxidoreductase from acidithiobacillus ferrooxidans. | the gene product of open reading frame afe_1293 from acidithiobacillus ferrooxidans atcc 23270 is annotated as encoding a sulfide:quinone oxidoreductase, an enzyme that catalyses electron transfer from sulfide to quinone. following overexpression in escherichia coli, the enzyme was purified and crystallized using the hanging-drop vapour-diffusion method. the native crystals belonged to the tetragonal space group p4(2)2(1)2, with unit-cell parameters a = b = 131.7, c = 208.8 a, and diffracted to ... | 2009 | 19652354 |
| transcriptional and functional studies of acidithiobacillus ferrooxidans genes related to survival in the presence of copper. | the acidophilic acidithiobacillus ferrooxidans can resist exceptionally high copper (cu) concentrations. this property is important for its use in biomining processes, where cu and other metal levels range usually between 15 and 100 mm. to learn about the mechanisms that allow a. ferrooxidans cells to survive in this environment, a bioinformatic search of its genome showed the presence of at least 10 genes that are possibly related to cu homeostasis. among them are three genes coding for putativ ... | 2009 | 19666734 |
| seasonal and spatial variations in microbial community structure and diversity in the acid stream draining across an ongoing surface mining site. | this study examined the microbial community in an acidic stream draining across the yun-fu pyrite mine (guangdong, china), where extremely acidic mine water is a persistent feature due to the intensive surface mining activities. analysis of terminal restriction fragment length polymorphism (trflp) of 16s rrna gene sequences showed that microbial populations varied spatially and seasonally and correlated with geochemical and physical conditions. after the stream moves from underground to the surf ... | 2009 | 19678846 |
| bioleaching of metals from printed wire boards by acidithiobacillus ferrooxidans and acidithiobacillus thiooxidans and their mixture. | bioleaching processes were used to mobilize metals from printed wire boards (pwbs). the bacteria acidithiobacillus ferrooxidans (a. ferrooxidans) and acidithiobacillus thiooxidans (a. thiooxidans) isolated from an acidic mine drainage were grown and acclimated in presence of pwbs and then used as bioleaching bacteria to solubilize metals from pwbs. the experimental results demonstrate that all the percentages of copper, lead, zinc solubilized into the leaching solution from actual pwbs basically ... | 2009 | 19699031 |
| extending the models for iron and sulfur oxidation in the extreme acidophile acidithiobacillus ferrooxidans. | acidithiobacillus ferrooxidans gains energy from the oxidation of ferrous iron and various reduced inorganic sulfur compounds at very acidic ph. although an initial model for the electron pathways involved in iron oxidation has been developed, much less is known about the sulfur oxidation in this microorganism. in addition, what has been reported for both iron and sulfur oxidation has been derived from different a. ferrooxidans strains, some of which have not been phylogenetically characterized ... | 2009 | 19703284 |
| a study on the toxic effects of chloride on the biooxidation efficiency of pyrite. | bioleaching operations in areas with limited chloride-free water and use of ashes and dust as neutralizing agents have motivated to study the chloride toxicity and tolerance level of the microorganisms. biooxidation of pyrite using chloride containing waste ash compared with ca(oh)(2)+nacl as neutralizing agent was investigated to evaluate the causes of low pyrite oxidation. both precipitation of jarosite as well as the toxic effect of chloride on the microorganisms were responsible for lower py ... | 2009 | 19720455 |
| cys92, cys101, cys197, and cys203 are crucial residues for coordinating the iron-sulfur cluster of rhda from acidithiobacillus ferrooxidans. | by proteomic analysis, we found a rhodanese-like protein(rhda) from acidithiobacillus ferrooxidans atcc 23270 whose c-terminal contained a cysteine motif (cys-xx-trp-xx-cys), known to bind iron-sulfur clusters. but so far, there were no articles to confirm the existence of iron-sulfur cluster in rhda. in this study, rhda gene from a. ferrooxidans atcc 23270 was cloned and expressed in escherichia coli, the protein was purified by one-step affinity chromatography to homogeneity. the uv-vis scanni ... | 2009 | 19727950 |
| oxidation of elemental sulfur, tetrathionate and ferrous iron by the psychrotolerant acidithiobacillus strain ss3. | mesophilic iron and sulfur-oxidizing acidophiles are readily found in acid mine drainage sites and bioleaching operations, but relatively little is known about their activities at suboptimal temperatures and in cold environments. the purpose of this work was to characterize the oxidation of elemental sulfur (s(0)), tetrathionate (s4o6(2-)) and ferrous iron (fe2+) by the psychrotolerant acidithiobacillus strain ss3. the rates of elemental sulfur and tetrathionate oxidation had temperature optima ... | 2009 | 19782750 |
| acidithiobacillus ferrivorans, sp. nov.; facultatively anaerobic, psychrotolerant iron-, and sulfur-oxidizing acidophiles isolated from metal mine-impacted environments. | phenotypic and genotypic analysis was carried out on four iron- and sulfur-oxidizing acidophilic bacteria (the "no-37 group") isolated from different parts of the world. 16s rrna phylogeny showed that they are highly related to each other, but are less related to the type strain of acidithiobacillus ferrooxidans. the no-37 group isolates are obligate chemolithoautotrophs, facultative anaerobes, diazotrophic, and psychrotolerant. they are less tolerant of extremely low ph, and in contrast to at. ... | 2010 | 19787416 |
| modeling and analysis of nanoscale interaction forces between acidithiobacillus ferrooxidans and afm tip. | the specificity exhibited by acidithiobacillus ferrooxidans, a chemolithoautotrophic acidophile, in their attachment to different sulphide minerals has resulted in effective physical separation of these minerals. this can be explained in terms of surface forces of interaction between the cells and substrates using afm. in the light of this, the present study reports interaction studies with a. ferrooxidans cells and an afm silicon nitride tip. the aim of the present investigation is to probe the ... | 2010 | 19800769 |
| type iv pili of acidithiobacillus ferrooxidans are necessary for sliding, twitching motility, and adherence. | we used conventional methods to investigate the mechanism by which acidithiobacillus ferrooxidans colonizes a solid surface by assessing pili-mediated sliding, twitching motility, and adherence. a. ferrooxidans slided to form circular oxidized zones around each colony. this suggested that slide motility occurs through pili or flagella, though a. ferrooxidans strains atcc 19859 and atcc 23270 lack flagella. the results of reverse transcription-pcr demonstrated that the putative major pili gene of ... | 2010 | 19806397 |
| [sulfur metabolite bacteria from waste water of gold miner tale-depot in kuzbass]. | | 2009 | 19827719 |
| bioleaching kinetics and multivariate analysis of spent petroleum catalyst dissolution using two acidophiles. | bioleaching studies were conducted to evaluate the recovery of metal values from waste petroleum catalyst using two different acidophilic microorganisms, acidithiobacillus ferrooxidans and acidithiobacillus thiooxidans. various leaching parameters such as contact time, ph, oxidant concentration, pulp densities, particle size, and temperature were studied in detail. activation energy was evaluated from arrhenius equation and values for ni, v and mo were calculated in case of both the acidophiles. ... | 2010 | 19879686 |
| comparative evaluation of microbial and chemical leaching processes for heavy metal removal from dewatered metal plating sludge. | the purpose of the study described in this paper was to evaluate the application of bioleaching technique involving acidithiobacillus ferrooxidans to recover heavy metals (zn, cu, ni, pb, cd and cr) in dewatered metal plating sludge (with no sulfide or sulfate compounds). the effect of some conditional parameters (i.e. ph, oxidation-reduction potential (orp), sulfate production) and operational parameters (i.e. pulp density of the sludge and agitation time) were investigated in a 3l completely m ... | 2010 | 19880247 |
| the role of acidithiobacillus ferrooxidans in alleviating the inhibitory effect of thiosulfate on the growth of acidophilic acidiphilium species isolated from acid mine drainage samples from garubathan, india. | several acidophilic chemolithoautotrophic and heterotrophic strains were isolated from acid mine drainage samples from garubathan, west bengal, india. the strains, chemolithoautotrophic dk6.1 and heterotrophic dkap1.1, used in this study were assigned to the species acidithiobacillus ferrooxidans and acidiphilium cryptum, respectively. unamended filtered and subsequently autoclaved elemental sulfur spent medium of a. ferrooxidans was used as the medium to study heterotrophic growth of a. cryptum ... | 2009 | 19898546 |
| production of glycolic acid by chemolithotrophic iron- and sulfur-oxidizing bacteria and its role in delineating and sustaining acidophilic sulfide mineral-oxidizing consortia. | glycolic acid was detected as an exudate in actively growing cultures of three chemolithotrophic acidophiles that are important in biomining operations, leptospirillum ferriphilum, acidithiobacillus (at.) ferrooxidans, and at. caldus. although similar concentrations of glycolic acid were found in all cases, the concentrations corresponded to ca. 24% of the total dissolved organic carbon (doc) in cultures of l. ferriphilum but only ca. 5% of the total doc in cultures of the two acidithiobacillus ... | 2010 | 19933342 |
| hydrogen sulfide removal from air by acidithiobacillus thiooxidans in a trickle bed reactor. | a strain of acidithiobacillus thiooxidans immobilized in polyurethane foam was utilized for h(2)s removal in a bench-scale trickle-bed reactor, testing the limits of acidity and so(4) (2-) accumulation. the use of this acidophilic strain resulted in remarkable stability in the performance of the system. the reactor maintained a >98-99 % h(2)s removal efficiency for c of up to 66 ppmv and empty bed residence time <or=12-15 s. removal of >98 % h(2)s was achieved under steady-state conditions, over ... | 2009 | 19937213 |
| microbial architecture of environmental sulfur processes: a novel syntrophic sulfur-metabolizing consortia. | microbial oxidation of sulfur-rich mining waste materials drives acid mine drainage (amd) and affects the global sulfur biogeochemical cycle. the generation of amd is a complex, dynamic process that proceeds via multiple reaction pathways. the role of natural consortia of microbes in amd generation, however, has received very little attention despite their widespread occurrence in mining environments. through a combination of geochemical experimentation and modeling, scanning transmission x-ray ... | 2009 | 19943646 |
| bioleaching of ultramafic tailings by acidithiobacillus spp. for co2 sequestration. | bioleaching experiments using various acid-generating substances, i.e., metal sulfides and elemental sulfur, were conducted to demonstrate the accelerated dissolution of chrysotile tailings collected from an asbestos mine near clinton creek, yukon, canada. columns, possessing an acid-generating substance colonized with acidithiobacillus sp., produced leachates with magnesium concentrations that were an order of magnitude greater than mine site waters or control column leachates. in addition, chr ... | 2010 | 19950896 |
| isolation and characterization of ferrous- and sulfur-oxidizing bacteria from tengchong solfataric region, china. | microbial oxidation and reduction of iron and sulfur are important parts of biogeochemical cycles in acidic environments such as geothermal solfataric regions. species of acidithiobacillus and leptospirillum are the common ferrous-iron and sulfur oxidizers from such environments. this study focused on the tengchong sofataric region, located in yunnan province, southwest china. based on cultivation, 9 strains that grow on ferrous-iron and sulfuric compounds were obtained. analysis of 16s rrna gen ... | 2009 | 19999973 |
| bioleaching of chalcopyrite concentrate using leptospirillum ferriphilum, acidithiobacillus ferrooxidans and acidithiobacillus thiooxidans in a continuous bubble column reactor. | to estimate the bioleaching performance of chalcopyrite for various hydraulic residence times (hrts), laboratory-scale bioleaching of chalcopyrite concentrate was carried out in a continuous bubble column reactor with three different hrts of 120, 80 and 40 h, respectively. an extraction rate and ratio of 0.578 g cu l(-1) h(-1) and 39.7%, respectively, were achieved for an hrt of 80 h at a solids concentration of 10% (w/v). lower bioleaching performances than this were obtained for a longer hrt o ... | 2010 | 20012335 |
| k30, h150, and h168 are essential residues for coordinating pyridoxal 5'-phosphate of o-acetylserine sulfhydrylase from acidithiobacillus ferrooxidans. | o-acetylserine sulfhydrylase (oass) is a key enzyme involved in the pathway of the cysteine biosynthesis. the gene of oass from acidithiobacillus ferrooxidans atcc 23270 was cloned and expressed in e. coli, the soluble protein was purified by one-step affinity chromatography to apparent homogeneity. colors and uv-vis scanning results of the recombinant protein confirmed that it was a pyridoxal 5'-phosphate (plp)-containing protein. sequence alignment and site-directed mutation of the enzyme reve ... | 2010 | 20033172 |
| [isolation, identification of acidithiobacillus sp. and its role in the removal of heavy metals from contaminated sediments]. | a sulfur-oxidizing bacterium fd97 was isolated from heavy metal-contaminated river sediments. according to the morphological characteristics and sequence analysis of 16s rdna of fd97, the strain was identified as acidithiobacillus sp.. the effects of temperature on heavy metals bioleaching efficiencies from contaminated sediments by using acidithiobacillus sp. fd97 were investigated in shake flask experiments. the tests were performed at four different temperatures in the range of 22-40 degrees ... | 2009 | 20063754 |
| [recent research progress on the biomining bacteria of acidithiobacillus caldus--a review]. | acidithiobacillus caldus (a. caldus) is one of the predominant biomining bacteria, which shows application prospect in biological metallurgy. it can enhance the biomining efficiency together with iron oxidation bacteria in mixed biomining system. based on the published papers and our study on this bacterium, we described the research progress on it from four aspects, including the biomining mechanism, arsenic-resistant mechanism, genome study and genetic reconstruction. furthermore, we discussed ... | 2009 | 20112666 |
| biosorption of inorganic and organic arsenic from aqueous solution by acidithiobacillus ferrooxidans by-3. | the traditional techniques for removing low concentration arsenic are unsuitable. the biosorption characteristics of arsenite (ias(iii)) and monomethyl arsonate (mma(v)) from aqueous solution by acidithiobacillus ferrooxidans by-3 (at. f by-3) were investigated as a function of ph, contact time, initial arsenic concentration, biomass dosage and temperature in this study. results indicated that langmuir isotherm model fitted better than freundlich model to the equilibrium data. analysis of kineti ... | 2010 | 20122794 |
| method development for electrotransformation of acidithiobacillus caldus. | acidithiobacillus caldus is an acidophilic, chemoautotrophic bacterium, plays important role in bioleaching. gene transformation into a. caldus is difficult and only the conjugation method was reported successful, which method was relatively sophisticated. in this research, electrotransformation of a. caldus species was achieved for the first time using a. caldus y-3 and plasmid pjrd215. transformants were confirmed by colony pcr specific to the str gene on pjrd215, and the recovery of the plasm ... | 2010 | 20134231 |
| microbiology. feasting on minerals. | | 2010 | 20150475 |
| analysis of iron- and sulfur-oxidizing bacteria in a treatment plant of acid rock drainage from a japanese pyrite mine by use of ribulose-1, 5-bisphosphate carboxylase/oxygenase large-subunit gene. | iron- and sulfur-oxidizing bacteria in a treatment plant of acid rock drainage (ard) from a pyrite mine in yanahara, okayama prefecture, japan, were analyzed using the gene (cbbl) encoding the large subunit of ribulose-1, 5-bisphosphate carboxylase/oxygenase (rubisco). analyses of partial sequences of cbbl genes from acidithiobacillus ferrooxidans, acidithiobacillus thiooxidans and acidithiobacillus caldus strains revealed the diversity in their cbbl gene sequences. in contrast to the presence o ... | 2010 | 20159572 |
| metal recovery from spent refinery catalysts by means of biotechnological strategies. | a bioleaching study aimed at recovering metals from hazardous spent hydroprocessing catalysts was carried out. the exhaust catalyst was rich in nickel (4.5 mg/g), vanadium (9.4 mg/g) and molybdenum (4.4 mg/g). involved microorganisms were iron/sulphur oxidizing bacteria. investigated factors were elemental sulphur addition, ferrous iron addition and actions contrasting a possible metal toxicity (either adding powdered activated charcoal or simulating a cross current process by means of periodica ... | 2010 | 20167424 |
| a novel process to treat spent petroleum catalyst using sulfur-oxidizing lithotrophs. | a novel process was developed using sulfur-oxidizing bacteria to extract metal values like ni, v and mo from spent petroleum catalyst. bacteria were grown in elemental sulfur media for five day and after filtering, the filtrate was used for leaching purpose. effect of different parameters such as contact time, particle size, pulp density and lixiviant composition were studied to find out the extent of metal leaching during the leaching process. xrd analysis proved the existence of v in oxide for ... | 2009 | 20183517 |
| functional roles of the aromatic residues in the stabilization of the [fe(4)s(4)] cluster in the iro protein from acidithiobacillus ferrooxidans. | the iro protein is a member of hipip family with the [fe(4)s(4)] cluster for electron transfer. many reports proposed that the conserved aromatic residues might be responsible for the stability of the iron-sulfur cluster in hipip. in this study, tyr10 was found to be a critical residue for the stability of the [fe(4)s(4)] cluster according to site-directed mutagenesis results. tyr10, phe26 and phe48 were essential for the stability of the [fe(4)s(4)] cluster under acidic condition. trp44 were no ... | 2010 | 20208432 |
| non-homogeneous biofilm modeling applied to bioleaching processes. | a two-dimensional non-homogeneous biofilm model is proposed for the first time to study chemical and biochemical reactions at the microorganism scale applied to biological metal leaching from mineral ores. the spatial and temporal relation between these reactions, microorganism growth and the morphological changes of the biofilm caused by solid inorganic precipitate formation were studied using this model. the model considers diffusion limitations due to accumulation of inorganic particles over ... | 2010 | 20229512 |
| crystal structure of sulfide:quinone oxidoreductase from acidithiobacillus ferrooxidans: insights into sulfidotrophic respiration and detoxification. | sulfide:quinone oxidoreductase from the acidophilic and chemolithotrophic bacterium acidithiobacillus ferrooxidans was expressed in escherichia coli and crystallized, and its x-ray molecular structure was determined to 2.3 a resolution for native unbound protein in space group p4(2)2(1)2 . the decylubiquinone-bound structure and the cys160ala variant structure were subsequently determined to 2.3 a and 2.05 a resolutions, respectively, in space group p6(2)22 . the enzymatic reaction catalyzed by ... | 2010 | 20303979 |
| organoarsenic resistance and bioremoval of acidithiobacillus ferrooxidans. | the tolerance and bioremoval of dimethylarsinic acid (dma(v)) by acidithiobacillus ferrooxidans (a. ferrooxidans) were investigated here. the inhibitory concentration (ic) of dma(v) was determined for a. ferrooxidans. the effects of various parameters such as ph, contact time, initial dma(v) concentration, biosorbent dose and temperature were systematically examined to study the biosorption processes. results indicated that langmuir model fitted better than freundlich model to the equilibrium da ... | 2010 | 20362439 |
| [microbial diversity and characteristics of cultivable microorganisms in bioleaching reactors]. | in order to study the microbial diversity and the characteristics of cultivable microorganisms in bioleaching reactors. | 2010 | 20387468 |
| specificity and mutational analysis of the metal-dependent 3-deoxy-d-manno-octulosonate 8-phosphate synthase from acidithiobacillus ferrooxidans. | 3-deoxy-d-manno-octulosonate 8-phosphate synthase (kdo8ps) catalyzes the reaction between phosphoenol pyruvate and d-arabinose 5-phosphate to generate kdo8p. this reaction is part of the biosynthetic pathway to 3-deoxy-d-manno-octulosonate, a component of the lipopolysaccharide of the gram-negative bacterial cell wall. two distinct groups of kdo8pss exist, differing by the absolute requirement of a divalent metal ion. in this study acidithiobacillus ferrooxidans kdo8ps has been expressed and pur ... | 2010 | 20406700 |
| community structure and dynamics of the free and attached microorganisms during moderately thermophilic bioleaching of chalcopyrite concentrate. | a mixed culture of moderately thermophiles showed good performance in bioleaching of chalcopyrite. its community structure was investigated by amplified ribosomal dna restriction analysis. the result shows that leptospirillum ferriphilum and acidithiobacillus caldus were the predominant bacteria and ferroplasma thermophilum, the only archaea, could be always detected during bioleaching. therefore, real-time pcr assay was performed to monitor these microorganisms' dynamics in the solution and on ... | 2010 | 20417095 |
| [separation of magnetic bacteria by using a magnetic separator]. | a magnetic separator was used to separate magnetic bacteria based on their magnetotactic characteristics. acidithiobacillus ferrooxidans, a bacterium that could synthesize intra-cellular nanometer magnetic particles, was investigated as an example. strong magnetic and weak magnetic cells were separated and collected. on average, the number of the magnetic particles present in the strong magnetic cells is more than that of the weak magnetic cells. moreover, semisolid-plate magnetophoresis showed ... | 2010 | 20432949 |
| an unconventional copper protein required for cytochrome c oxidase respiratory function under extreme acidic conditions. | very little is known about the processes used by acidophile organisms to preserve stability and function of respiratory pathways. here, we reveal a potential strategy of these organisms for protecting and keeping functional key enzymes under extreme conditions. using acidithiobacillus ferrooxidans, we have identified a protein belonging to a new cupredoxin subfamily, acop, for "acidophile cco partner," which is required for the cytochrome c oxidase (cco) function. we show that it is a multifunct ... | 2010 | 20442397 |
| volatilization of metal mercury from organomercurials by highly mercury-resistant acidithiobacillus ferrooxidans mon-1. | the iron-oxidizing bacterium acidithiobacillus ferrooxidans mon-1 is highly resistant not only to mercuric chloride (hgcl(2)) but also to organomercurials such as methylmercury chloride (mmc). we have found that cytochrome c oxidase, purified from strain mon-1, reduces hg(2+) to volatilizable metal mercury (hg(0)) with reduced mammalian cytochrome c or fe(2+) as an electron donor. in this study we found that cytochrome c oxidase can volatilize hg(0) from mmc as well as from hg(2+) with reduced m ... | 2010 | 20460735 |
| gene expression modulation by chalcopyrite and bornite in acidithiobacillus ferrooxidans. | acidithiobacillus ferrooxidans is a mesophilic, acidophilic, chemolithoautotrophic bacterium that obtains energy from the oxidation of ferrous iron (fe2+), elemental sulfur and reduced sulfur compounds. the industrial interest in a. ferrooxidans resides in its capacity to oxidize insoluble metal sulfides into soluble metal sulfates, thus allowing the recovery of the desired metals from low-grade sulfide ores. in the present work, rna arbitrarily primed pcr (rap-pcr) was performed to identify cdn ... | 2010 | 20480358 |
| redox status affects the catalytic activity of glutamyl-trna synthetase. | glutamyl-trna synthetases (glurs) provide glu-trna for different processes including protein synthesis, glutamine transamidation and tetrapyrrole biosynthesis. many organisms contain multiple glurss, but whether these duplications solely broaden trna specificity or also play additional roles in tetrapyrrole biosynthesis is not known. previous studies have shown that glurs1, one of two glurss from the extremophile acidithiobacillus ferrooxidans, is inactivated when intracellular heme is elevated ... | 2010 | 20541532 |
| recombinant tetrathionate hydrolase from acidithiobacillus ferrooxidans requires exposure to acidic conditions for proper folding. | tetrathionate hydrolase (4thase) plays an important role in dissimilatory sulfur metabolism in the acidophilic chemolithoautotrophic iron- and sulfur-oxidizing bacterium acidithiobacillus ferrooxidans. we have already identified the gene encoding 4thase (af-tth) in this bacterium. the heterologous expression of af-tth in escherichia coli resulted in the formation of inclusion bodies of the protein in an inactive form. the recombinant protein (af-tth) was successfully activated after an in vitro ... | 2010 | 20546308 |
| environmental transcriptome analysis reveals physiological differences between biofilm and planktonic modes of life of the iron oxidizing bacteria leptospirillum spp. in their natural microbial community. | extreme acidic environments are characterized by their high metal content and lack of nutrients (oligotrophy). macroscopic biofilms and filaments usually grow on the water-air interface or under the stream attached to solid substrates (streamers). in the río tinto (spain), brown filaments develop under the water stream where the gram-negative iron-oxidizing bacteria leptospirillum spp. (l. ferrooxidans and l. ferriphilum) and acidithiobacillus ferrooxidans are abundant. these microorganisms play ... | 2010 | 20576116 |
| isolation and characterization of acidithiobacillus caldus from a sulfur-oxidizing bacterial biosensor and its role in detection of toxic chemicals. | a novel toxicity detection methodology based on sulfur-oxidizing bacteria (sob) has been developed for the rapid and reliable detection of toxic chemicals in water. the methodology exploits the ability of sob to oxidize sulfur particles in the presence of oxygen to produce sulfuric acid. the reaction results in an increase in electrical conductivity (ec) and a decrease in ph. the assay is based on the inhibition of sob in the presence of toxic chemicals by measuring changes in ec and ph. we foun ... | 2010 | 20580751 |
| cytoplasmic membrane fluidity and fatty acid composition of acidithiobacillus ferrooxidans in response to ph stress. | strain variation in the acidophile acidithiobacillus ferrooxidans was examined as a product of membrane adaptation in response to ph stress. we tested the effects of sub and supra-optimal ph in two type strains and four strains isolated from acid mine drainage water around sudbury, ontario, canada. growth rate, membrane fluidity and phase, determined from the fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene, and fatty acid profiles were compared. the effect of ph 1.5 was the most prono ... | 2010 | 20582711 |
| monitoring bacterial community shifts in bioleaching of ni-cu sulfide. | the microbial ecology of the bioleaching of ni-cu sulfide is poorly understood and little effort has been made to handle the microbiological components of these processes. in this study, denaturing gradient gel electrophoresis (dgge) analysis of pcr-amplified 16s rrna genes fragments from bacteria was used to evaluate the changes of the bacterial community in the process of ni-cu sulfide bioleaching in a shaken flask system. the results revealed that the bacterial community was disturbed after t ... | 2010 | 20624605 |
| life in blue: copper resistance mechanisms of bacteria and archaea used in industrial biomining of minerals. | industrial biomining processes to extract copper, gold and other metals involve the use of extremophiles such as the acidophilic acidithiobacillus ferrooxidans (bacteria), and the thermoacidophilic sulfolobus metallicus (archaea). together with other extremophiles these microorganisms subsist in habitats where they are exposed to copper concentrations higher than 100mm. herein we review the current knowledge on the cu-resistance mechanisms found in these microorganisms. recent information sugges ... | 2010 | 20627124 |
| cytoplasmic membrane response to copper and nickel in acidithiobacillus ferrooxidans. | metal tolerance has been found to vary among acidithiobacillus ferrooxidans strains and this can impact the efficiency of biomining practices. to explain observed strain variability for differences in metal tolerance we examined the effects of cu(2+) and ni(2+) concentrations (1-200 mm) on cytoplasmic membrane properties of two a. ferrooxidans type strains (atcc 23270 and 19859) and four strains isolated from amd water around sudbury, ontario, canada. growth rate, membrane fluidity and phase, de ... | 2011 | 20630730 |
| heterotrophic microorganism rhodotorula mucilaginosa r30 improves tannery sludge bioleaching through elevating dissolved co2 and extracellular polymeric substances levels in bioleach solution as well as scavenging toxic dom to acidithiobacillus species. | the introduction of acid-tolerant heterotrophic microorganisms into sludge bioleaching systems has been proven effective in improving sludge bioleaching processes, and such positive effect is mainly attributed to the biodegradation of low molecular weight organic acids or sludge dissolved organic matter (dom) toxic to acidithiobacillus species by the heterotrophic microorganisms introduced. here we report that elevated dissolved co(2) concentration and resulting extracellular polymeric substance ... | 2010 | 20633920 |
| overexpression of rusticyanin in acidithiobacillus ferrooxidans atcc19859 increased fe(ii) oxidation activity. | a wide-host-range plasmid ptrus containing a homologous rus gene under the control of ptac promoter was constructed and transferred into acidithiobacillus ferrooxidans atcc19859 using conjugation gene transfer method to generate the engineered strain of a. ferrooxidans(ptrus). the plasmid-based recombinant rus gene was successfully expressed. according to the results of real-time quantitative pcr assay, not only the transcription level of recombinant rus gene but also the transcription levels of ... | 2011 | 20644934 |