thiobacillus ferrooxidans detection using immunoelectron microscopy.a specific, fast and very sensitive immunoelectron microscopy method was developed to morphologically and serologically distinguish different cultures of iron oxidizers. bacteria isolated from the acidic waters of "matahambre" and "mina delita" mines (cuba) were characterized. an antiserum specific to thiobacillus ferrooxidans did not react with other bacteria also present in the acidic waters of mine drainage. our results suggest the occurrence of some strains of thiobacillus ferrooxidans, thio ...19921492954
chemotaxis of leptospirillum ferrooxidans and other acidophilic chemolithotrophs: comparison with the escherichia coli chemosensory system.ni2+, fe2+ and cu2+ were attractants and aspartate was an apparent repellent for leptospirillum ferrooxidans, a behaviour opposite to that for escherichia coli. membranes from l. ferrooxidans contained proteins with a molecular mass in the range of 80 kda which were methylated in vitro. methylation was stimulated in the presence of a membrane-free extract from e. coli, showing the response pattern expected for l. ferrooxidans, increased methylation by ni2+, and demethylation by aspartate. this s ...19921526464
isolation and characterization of an acidophilic, heterotrophic bacterium capable of oxidizing ferrous iron.a heterotrophic bacterium, isolated from an acidic stream in a disused pyrite mine which contained copious growths of "acid streamers," displayed characteristics which differentiated it from previously described mesophilic acidophiles. the isolate was obligately acidophilic, with a ph range of 2.0 to 4.4 and an optimum ph of 3.0. the bacterium was unable to fix carbon dioxide but oxidized ferrous iron, although at a slower rate than either thiobacillus ferrooxidans or leptospirillum ferrooxidans ...19921622207
evolutionary relationships among sulfur- and iron-oxidizing eubacteria.some 37 reverse transcriptase, partial 16s rrna sequences from sulfur- and/or iron-oxidizing eubacteria, including sequences from species of the genera thiobacillus, thiothrix, thiomicrospira, acidophilium, "leptospirillum," thiovulum, and chlorobium, have been determined. in addition, 16s sequences from a number of unnamed sulfur- and/or iron-oxidizing bacteria from hydrothermal vent sites, from invertebrate-bacterial endosymbioses, and from various mineral recovery operations also have been de ...19921729214
distribution of oxidizing bacterial activities and characterization of bioleaching-related microorganisms in a uranium mineral heap.the occurrence and activity of bioleaching-related microorganisms are highest at 0.25 m under the surface of a uranium mineral heap, and decrease at points deeper than 1 m inside the heap. thiobacillus ferrooxidans, th. acidophilus, th. thiooxidans and leptospirillum ferrooxidans have been found and isolated from different sites inside the heap. other mesophilic iron- or sulphur-oxidizing bacteria and some moderate thermophile have also been isolated from deep (1 m and 4 m) sites and characteriz ...19911760138
thiobacillus ferrooxidans, a facultative hydrogen oxidizer.the type strain (atcc 23270) and two other strains of thiobacillus ferrooxidans were able to grow by hydrogen oxidation, a feature not recognized before. when cultivated on h2, a hydrogenase was induced and the strains were less extremely acidophilic than during growth on sulfidic ores. cells of t. ferrooxidans grown on h2 and on ferrous iron showed 100% dna homology. hydrogen oxidation was not observed in eight other species of the genus thiobacillus and in leptospirillum ferrooxidans.19902275538
[leptospirillum ferrooxidans and characteristics of its autotrophic growth]. 19744217875
cultural and phylogenetic analysis of mixed microbial populations found in natural and commercial bioleaching environments.a range of autotrophic and heterotrophic enrichment cultures were established to determine the cultural bacterial diversity present in samples obtained from the acidic runoff of a chalcocite overburden heap and from laboratory-scale (1- to 4-liter) batch and continuous bioreactors which were being used for the commercial assessment of the bioleachability of zinc sulfide ore concentrates. strains identified as thiobacillus ferrooxidans, thiobacillus thiooxidans, "leptospirillum ferrooxidans," and ...19947517131
isolation and study of two strains of leptospirillum-like bacteria from a natural mixed population cultured on a cobaltiferous pyrite substrate.two strains of leptospirillum-like bacteria, l6 and l8, have been isolated from a mixed inoculum, also containing thiobacillus ferrooxidans and t. thiooxidans, cultured for one year with a colbaltiferous pyrite as energy substrate in a 100 l continuous bioleaching laboratory unit. several physiological properties of the strains are described. the vibrio-shaped microorganisms grew at ph values lower than 1.3. their growth rate was maximum between 2.5 and 8.0 g l1 ferrous iron. the optimal growth ...19947710275
[application of immunologic methods to the analysis of bio-leaching bacteria].pure cultures of thiobacillus ferrooxidans and mixed cultures of thiobacillus ferrooxidans and leptospirillum ferrooxidans isolated from the matahambre mine (cuba) were used to fit immunodiffusion and immunoelectron microscopy to the study of iron oxidizing bacteria. the possibilities, advantages and limits of those techniques have been studied from both the identification and the serological characterization points of view. finally, the efficiency of these methods was tested by applying them to ...19947873106
enzymes of aerobic respiration on iron.bacteria capable of aerobic respiration on ferrous ions are spread throughout eubacterial and archaebacterial phyla. comparative spectroscopic analyses revealed that phylogenetically distinct organisms expressed copious quantities of spectrally distinct redox-active biomolecules during autotrophic growth on soluble iron. thiobacillus ferroxidans, leptospirillum ferrooxidans, sulfobacillus thermosulfidooxidans, and metallosphaera sedula possessed iron respiratory chains dominated by a blue copper ...19938357617
pcr-mediated detection of the chemolithotrophic bacterium thiobacillus cuprinus using 23s rdna- and 16s/23s intergenic spacer region-targeted oligonucleotide primers.bioleaching is carried out by chemolithotrophic microorganisms, most of them belonging to the genera thiobacillus and leptospirillum. the role of the mixotrophic species t. cuprinus in this process is controversial, since its ecological study applying classical detection techniques to natural or industrial environments is very difficult. for this reason, we have developed an alternative method based on pcr-mediated detection using specific oligonucleotide primers that target variable regions of ...19968810512
bacterial populations in samples of bioleached copper ore as revealed by analysis of dna obtained before and after cultivation.the composition of bacterial populations in copper bioleaching systems was investigated by analysis of dna obtained either directly from ores or leaching solutions or after laboratory cultures. this analysis consisted of the characterization of the spacer regions between the 16 and 23s genes in the bacterial rrna genetic loci after pcr amplification. the sizes of the spacer regions, amplified from dnas obtained from samples, were compared with the sizes of those obtained from cultures of the mai ...19968919792
distribution of thiobacillus ferrooxidans and leptospirillum ferrooxidans: implications for generation of acid mine drainagealthough thiobacillus ferrooxidans and leptospirillum ferrooxidans are widely considered to be the microorganisms that control the rate of generation of acid mine drainage, little is known about their natural distribution and abundance. fluorescence in situ hybridization studies showed that at iron mountain, california, t. ferrooxidans occurs in peripheral slime-based communities (at ph over 1.3 and temperature under 30 degreesc) but not in important subsurface acid-forming environments (ph 0.3 ...19989488647
a tn7-like transposon is present in the glmus region of the obligately chemoautolithotrophic bacterium thiobacillus ferrooxidans.the region downstream of the thiobacillus ferrooxidans atcc 33020 atp operon was examined, and the genes encoding n-acetylglucosamine-1-uridyltransferase (glmu) and glucosamine synthetase (glms) were found. this atpefhagdc-glmus gene order is identical to that of escherichia coli. the t. ferrooxidans glms gene was shown to complement e. coli glms mutants for growth on minimal medium lacking glucosamine. a tn7-like transposon, tn5468, was found inserted into the region immediately downstream of t ...19989603897
kinetics of ferrous iron oxidation by leptospirillum bacteria in continuous cultures.the oxidation of ferrous iron by leptospirillum bacteria was studied in a continuous culture in the dilution rate range 0.009-0.077 h-1 and could be described with a rate equation for competitive ferric iron inhibition kinetics in terms of the ferric/ferrous iron ratio in the solution. the ferrous iron oxidation in the continuous culture was followed by means of oxygen and carbon dioxide concentration analyses in reference air and off-gas. from these measurements the oxygen consumption rate, ro2 ...19989622523
molecular cloning, sequencing, and expression of a chemoreceptor gene from leptospirillum ferrooxidans.we have cloned and sequenced a 2,262-bp chromosomal dna fragment from the chemolithoautotrophic acidophilic bacterium leptospirillum ferrooxidans. this dna contained an open reading frame for a 577-amino-acid protein showing several characteristics of the bacterial chemoreceptors and, therefore, we named this gene lcri for leptospirillum chemotaxis receptor i. this is the first sequence reported for a gene from l. ferrooxidans encoding a protein. the lcri gene showed both sigma 28-like and sigma ...19989647803
genomic organization analysis of acidophilic chemolithotrophic bacteria using pulsed field gel electrophoretic techniques.the genomic organization of acidophilic chemolithotrophic bacteria belonging to the genus thiobacillus, thiomonas and leptospirillum was studied using pulsed field gel electrophoresis techniques (pfge). the electrophoretic analysis of intact dna prepared from different strains showed that all have a circular chromosome, with sizes ranging from 1.9 mb for leptospirillum ferrooxidans atcc 49879, the smallest genome for an acidophilic strict chemolithoautotrophic microorganism, to 3.8 mb for thiomo ...19989893951
reasons why 'leptospirillum'-like species rather than thiobacillus ferrooxidans are the dominant iron-oxidizing bacteria in many commercial processes for the biooxidation of pyrite and related ores. 199910206710
seasonal variations in microbial populations and environmental conditions in an extreme acid mine drainage environment.microbial populations, their distributions, and their aquatic environments were studied over a year (1997) at an acid mine drainage (amd) site at iron mountain, calif. populations were quantified by fluorescence in situ hybridizations with group-specific probes. probes were used for the domains eucarya, bacteria, and archaea and the two species most widely studied and implicated for their role in amd production, thiobacillus ferrooxidans and leptospirillum ferrooxidans. results show that microbi ...199910427059
the effect of temperature on the continuous ferrous-iron oxidation kinetics of a predominantly leptospirillum ferrooxidans culture.the ferrous-iron oxidation kinetics of a bacterial culture consisting predominantly of leptospirillum ferrooxidans were studied in continuous-flow bioreactors. the bacterial culture was fed with a salts solution containing 12 g/l ferrous-iron, at dilution rates ranging from 0.01 to 0.06 l/h, and temperatures ranging from 30 to 40 degrees c, at a ph of 1.75. the growth rate, and the oxygen and ferrous-iron utilization rates of the bacteria, were monitored by means of off-gas analysis and redox-po ...199910440670
leptospirillum gen. nov. (ex markosyan 1972), nom. rev., including leptospirillum ferrooxidans sp. nov. (ex markosyan 1972), nom. rev. and leptospirillum thermoferrooxidans sp. nov. (golovacheva et al. 1992).the name leptospirillum ferrooxidans is not in the approved lists of bacterial names (1980), nor has it been subsequently validly published. in accordance with the rules of the international code of nomenclature of bacteria, the name leptospirillum for the genus (gen. nov., nom. rev.) and leptospirillum ferrooxidans for the species (sp. nov., nom. rev.) is revived here. the type species is leptospirillum ferrooxidans strain l15t (= dsm 2705t). the second species in the genus is leptospirillum th ...200010758852
production of rhodanese by bacteria present in bio-oxidation plants used to recover gold from arsenopyrite concentrates.considerably larger quantities of cyanide are required to solubilize gold following the bio-oxidation of gold-bearing ores compared with oxidation by physical-chemical processes. a possible cause of this excessive cyanide consumption is the presence of the enzyme rhodanese. rhodanese activities were determined for the bacteria most commonly encountered in bio-oxidation tanks. activities of between 6.4 and 8.2 micromol scn min(-1) mg protein(-1) were obtained for crude enzyme extracts of thiobaci ...200010945796
phylogeny of microorganisms populating a thick, subaerial, predominantly lithotrophic biofilm at an extreme acid mine drainage unusually thick ( approximately 1 cm) slime developed on a slump of finely disseminated pyrite ore within an extreme acid mine drainage site at iron mountain, near redding, calif. the slime was studied over the period of 1 year. the subaerial form of the slime distinguished it from more typical submerged streamers. phylogenetic analysis of 16s rrna genes revealed a diversity of sequences that were mostly novel. nearest relatives to the majority of sequences came from iron-oxidizing acidophile ...200010966399
high density cultivation of two strains of iron-oxidizing bacteria through reduction of ferric iron by intermittent electrolysis.electrolytic cultivation was applied to leptospirillum ferrooxidans strains p3a and cf27, which use ferrous iron to respire aerobically. ferrous iron was supplied to the bacteria by intermittent electrolytic reduction of ferric iron as electron shuttle using an electrode. the yield of l. ferrooxidans and strain cf27 reached 20- and 50-fold, respectively, higher density than were achievable yields without electrolysis. the time required to obtain high density depended not on the growth ratio, but ...200011005929
comparison of acid mine drainage microbial communities in physically and geochemically distinct ecosystems.this study presents population analyses of microbial communities inhabiting a site of extreme acid mine drainage (amd) production. the site is the inactive underground richmond mine at iron mountain, calif., where the weathering of a massive sulfide ore body (mostly pyrite) produces solutions with phs of approximately 0.5 to approximately 1.0. here we used a suite of oligonucleotide probes, designed from molecular data recently acquired from the site, to analyze a number of microbial environment ...200011055950
isolation and some properties of a mesophilic and mixotrophic iron-oxidizing bacterium, iron-oxidizing bacterium strain, okm-9, isolated from mud obtained from the bottom of a pond, minamikata ohike, in okayama prefecture, japan, grew well in an feso4 x 7h2o (3%)-medium (ph 2.5) with 0.03% yeast extract. however, the strain could not grow either in an feso4 x 7h2o (3%)-medium without yeast extract or in a yeast extract (0.03%)-medium (ph 2.5) without fe2+. the strain did not use elemental sulfur as an energy source and did not have the activity to fix carbon dioxide. strain okm- ...200011129576
monitoring of bacteria in acid mine environments by reverse sample genome probing.a variety of microorganisms can exist in acid mine drainage (amd) environments, although their contribution to amd problems is unclear. environmental strains of thiobacillus ferrooxidans and thiobacillus acidophilus were purified by repeated plating and single-colony isolation on iron salts and tetrathionate media, respectively. thiobacillus thiooxidans was enriched on sulfur-containing media. for the isolation of leptospirillum ferrooxidans, iron salts and pyrite media were inoculated with envi ...200111400734
identification of thiobacillus ferrooxidans strains based on restriction fragment length polymorphism analysis of 16s rdna.the 16s rdna sequences from ten strains of thiobacillus ferrooxidans were amplified by pcr. the products were compared by performing restriction fragment length polymorphism (rflp) analysis with restriction endonucleases alu i, hap ii, hha i, and hae iii. the rflp patterns revealed that t. ferrooxidans could be distinguished from other iron- or sulphur-oxidizing bacteria such as t. thiooxidans nb1-3, t. caldus go-1, leptospirillum ferrooxidans and the marine iron-oxidizing bacterium strain ku2-1 ...200111414499
isolation and phylogenetic characterization of acidophilic microorganisms indigenous to acidic drainage waters at an abandoned norwegian copper mine.the biodiversity of culturable acidophilic microbes in three acidic (ph 2.7-3.7), metal-rich waters at an abandoned subarctic copper mine in central norway was assessed. acidophilic bacteria were isolated by plating on selective solid media, and dominant isolates were identified from their physiological characteristics and 16s rrna gene sequences. the dominant iron-oxidizing acidophile in all three waters was an acidithiobacillus ferrooxidans-like eubacterium, which shared 98% 16s rdna identity ...200111722543
molecular relationship between two groups of the genus leptospirillum and the finding that leptospirillum ferriphilum sp. nov. dominates south african commercial biooxidation tanks that operate at 40 degrees c.iron-oxidizing bacteria belonging to the genus leptospirillum are of great importance in continuous-flow commercial biooxidation reactors, used for extracting metals from minerals, that operate at 40 degrees c or less. they also form part of the microbial community responsible for the generation of acid mine drainage. more than 16 isolates of leptospirilla were included in this study, and they were clearly divisible into two major groups. group i leptospirilla had g+c moles percent ratios within ...200211823226
design and performance of rrna targeted oligonucleotide probes for in situ detection and phylogenetic identification of microorganisms inhabiting acid mine drainage iron mountain, ca, there is an extreme occurrence of acid mine drainage (amd). this is a result of past mining activity that has exposed a sulfide ore body to weathering and microbial activity. this study presents seven new oligonucleotide probes for the detection of microorganisms at this amd site by fluorescent in situ hybridization. in the design of these probes we have accounted for a large body of 16s rrna sequence data recently compiled by us. this was obtained by pcr and cloning direct ...200112032620
monitoring of a pyrite-oxidising bacterial population using dna single-strand conformation polymorphism and microscopic techniques.the single-strand conformation polymorphism (sscp) technique was used to study the evolution of a bacterial consortium during the batch oxidation of a cobaltiferous pyrite in two types of bio-reactor: a bubble column and a classical stirred tank. sequencing 16s rdna revealed the presence of three organisms affiliated to leptospirillum ferrooxidans, acidithiobacillus thiooxidans and sulfobacillus thermosulfidooxidans, respectively. attempts were made to determine the proportions of bacteria attac ...200212382065
recovery of novel bacterial diversity from a forested wetland impacted by reject coal.sulphide mineral mining together with improperly contained sulphur-rich coal represents a significant environmental problem caused by leaching of toxic material. the savannah river site's d-area harbours a 22-year-old exposed reject coal pile (rcp) from which acidic, metal rich, saline runoff has impacted an adjacent forested wetland. in order to assess the bacterial community composition of this region, composite sediment samples were collected at three points along a contamination gradient (hi ...200212460285
enumeration and characterization of acidophilic microorganisms isolated from a pilot plant stirred-tank bioleaching operation.microorganisms were enumerated and isolated on selective solid media from a pilot-scale stirred-tank bioleaching operation in which a polymetallic sulfide concentrate was subjected to biologically accelerated oxidation at 45 degrees c. four distinct prokaryotes were isolated: three bacteria (an acidithiobacillus caldus-like organism, a thermophilic leptospirillum sp., and a sulfobacillus sp.) and one archaeon (a ferroplasma-like isolate). the relative numbers of these prokaryotes changed in the ...200312676667
gene function analysis in environmental isolates: the nif regulon of the strict iron oxidizing bacterium leptospirillum ferrooxidans.a random genomic library from an environmental isolate of the gram-negative bacterium leptospirillum ferrooxidans has been printed on a microarray. gene expression analysis was carried out with total rna extracted from l. ferrooxidans cultures in the presence or absence of ammonium as nitrogen source under aerobic conditions. although practically nothing is known about the genome sequence of this bacterium, this approach allowed us the selection and sequencing of only those clones bearing genes ...200312808145
characterization and identification of an iron-oxidizing, leptospirillum-like bacterium, present in the high sulfate leaching solution of a commercial bioleaching plant.most copper bioleaching plants operate with a high concentration of sulfate salts, caused by the continuous addition of sulfuric acid and the recycling of the leaching solution. since the bacteria involved in bioleaching have been generally isolated at low sulfate concentrations, the bacterial population present in the high-sulfate (150 gl(-1)) leaching solution, employed in a copper production plant, was investigated. the iron-oxidizing bacteria able to grow in the leaching solution were enrich ...200312837511
microbial ecology of an extreme acidic environment, the tinto river.the tinto river (huelva, southwestern spain) is an extreme environment with a rather constant acidic ph along the entire river and a high concentration of heavy metals. the extreme conditions of the tinto ecosystem are generated by the metabolic activity of chemolithotrophic microorganisms thriving in the rich complex sulfides of the iberian pyrite belt. molecular ecology techniques were used to analyze the diversity of this microbial community. the community's composition was studied by denatur ...200312902280
[leptospirillum-like bacteria and their role in pyrite oxidation].two strains of leptospirillum-like bacteria isolated from dumps of alaverdi and akhtala sulfide ore deposits in armenia were studied. the optimum and maximum temperatures for the growth of both strains were 37 and 40 degrees c, respectively. the ph optimum was 2.0-2.3. bacterial growth and ferrous iron oxidation were inhibited by yeast extract. the pyrite-leaching activity of the leptospirillum-like bacteria under mesophilic conditions was close to that of acidithiobacillus ferroxidans and excee ...200314526539
bioleaching review part a: progress in bioleaching: fundamentals and mechanisms of bacterial metal sulfide oxidation.bioleaching of metal sulfides is caused by astonishingly diverse groups of bacteria. today, at least 11 putative prokaryotic divisions can be related to this phenomenon. in contrast, the dissolution (bio)chemistry of metal sulfides follows only two pathways, which are determined by the acid-solubility of the sulfides: the thiosulfate and the polysulfide pathway. the bacterial cell can effect this sulfide dissolution by "contact" and "non-contact" mechanisms. the non-contact mechanism assumes tha ...200314566432
diverse microbial communities inhabiting ferromanganese deposits in lechuguilla and spider caves.lechuguilla cave is an ancient, deep, oligotrophic subterranean environment that contains an abundance of low-density ferromanganese deposits, the origin of which is uncertain. to assess the possibility that biotic factors may be involved in the production of these deposits and to investigate the nature of the microbial community in these materials, we carried out culture-independent, small subunit ribosomal rna (ssu rrna) sequence-based studies from two sites and from manganese and iron enrichm ...200314641587
linking autotrophic activity in environmental samples with specific bacterial taxa by detection of 13c-labelled fatty acids.a method for the detection of physiologically active autotrophic bacteria in complex microbial communities was developed based on labelling with the stable isotope 13c. labelling of autotrophic nitrifying, sulphur-oxidizing and iron-oxidizing populations was performed in situ by incubation with nah[13c]o3. incorporated label into fatty acid methyl esters (fames) was detected and quantified using gas chromatography-mass spectrometry in single ion monitoring mode. before the analyses of different ...200314641595
community structure and metabolism through reconstruction of microbial genomes from the environment.microbial communities are vital in the functioning of all ecosystems; however, most microorganisms are uncultivated, and their roles in natural systems are unclear. here, using random shotgun sequencing of dna from a natural acidophilic biofilm, we report reconstruction of near-complete genomes of leptospirillum group ii and ferroplasma type ii, and partial recovery of three other genomes. this was possible because the biofilm was dominated by a small number of species populations and the freque ...200414961025
high-rate ferric sulfate generation by a leptospirillum ferriphilum-dominated biofilm and the role of jarosite in biomass retention in a fluidized-bed reactor.the aims of this work were to develop a high-rate fluidized-bed bioprocess for ferric sulfate production, to characterize biomass retention, and to determine the phylogeny of the enrichment culture. after 7 months of continuous enrichment and air aeration at 37 degrees c, the iron oxidation rate of 8.2 g fe(2+) l(-1)h(-1) (4.5.10(-12) g fe(2+) cell(-1) h(-1)) was obtained at a hydraulic retention time (hrt) of 0.6 h. however, oxygen supply became the rate-limiting factor. with gas mixture (99.5% ...200414991647
microbiological and chemical characteristics of an acidic stream draining a disused copper mine.water samples draining a disused copper mine (parys mountain) in anglesey, north wales, were analysed for distribution of acidophilic bacteria (iron oxidising and heterotrophic) and for changes in physicochemical composition along the length of the drainage stream. ten samples were taken at regular distance intervals along a 1 km stretch from the source of the acid mine drainage. the stream remained highly acidic (ph < 2.8) although a slight decrease (0.6 ph unit) in acidity with distance from s ...199215091999
macrofilamentous microbial communities in the metal-rich and acidic river tinto, spain.a novel type of macroscopic microbial community consisting of large dendritic filaments (up to 1.5 m) in a ph 2.0 dam of the river tinto (south-western spain) is described. the combined use of 16s rrna-gene surveys and fluorescent in situ hybridisation (fish) suggested that gamma-proteobacteria and a relative large diversity of alpha-proteobacteria dominated these structures. beta-proteobacteria, actinobacteria and firmicutes were also detected. whereas acidophilic bacteria of the genera acidith ...200415183867
biooxidation of pyrite by defined mixed cultures of moderately thermophilic acidophiles in ph-controlled bioreactors: significance of microbial interactions.the oxidative dissolution of pyrite (fes2) by pure and mixed cultures of moderately thermophilic acidophiles was studied in shake flask cultures and in ph-controlled bioreactors, incubated at 45 degrees c. various combinations of seven eubacteria (a leptospirillum sp. (mt6), acidimicrobium ferrooxidans, acidithiobacillus caldus, an alicyclobacillus sp. (y004), and three sulfobacillus spp.) and one archaeon (ferroplasma sp. mt17) were examined. pyrite dissolution was determined by measuring chang ...200415352055
nitrogen fixation in acidophile iron-oxidizing bacteria: the nif regulon of leptospirillum ferrooxidans.the gram-negative iron-oxidizing bacterium leptospirillum ferrooxidans contains all genes necessary for nitrogen fixation, from genes encoding the mo-fe nitrogenase, the specific regulator (nifa), global regulators like glnb and ntrc like genes, to other sensors and transport systems somehow related to nitrogen assimilation. we review current knowledge about the nif regulon and its connection with other metabolic functions in l. ferrooxidans.200415501646
high-rate acidophilic ferrous iron oxidation in a biofilm airlift reactor and the role of the carrier this study, the feasibility and engineering aspects of acidophilic ferrous iron oxidation in a continuous biofilm airlift reactor inoculated with a mixed culture of acidithiobacillus ferrooxidans and leptospirillum ferrooxidans bacteria were investigated. specific attention was paid to biofilm formation, competition between both types of bacteria, ferrous iron oxidation rate, and gas liquid mass transfer limitations. the reactor was operated at a constant temperature of 30 degrees c and at ph ...200515772947
community proteomics of a natural microbial biofilm.using genomic and mass spectrometry-based proteomic methods, we evaluated gene expression, identified key activities, and examined partitioning of metabolic functions in a natural acid mine drainage (amd) microbial biofilm community. we detected 2033 proteins from the five most abundant species in the biofilm, including 48% of the predicted proteins from the dominant biofilm organism, leptospirillum group ii. proteins involved in protein refolding and response to oxidative stress appeared to be ...200515879173
genomic insights into the iron uptake mechanisms of the biomining microorganism acidithiobacillus ferrooxidans.commercial bioleaching of copper and the biooxidation of gold is a cost-effective and environmentally friendly process for metal recovery. a partial genome sequence of the acidophilic, bioleaching bacterium acidithiobacillus ferrooxidans is available from two public sources. this information has been used to build preliminary models that describe how this microorganism confronts unusually high iron loads in the extremely acidic conditions (ph 2) found in natural environments and in bioleaching o ...200515895264
iron meteorites can support the growth of acidophilic chemolithoautotrophic microorganisms.chemolithoautotrophy based on reduced inorganic minerals is considered a primitive energy transduction system. evidence that a high number of meteorites crashed into the planet during the early period of earth history led us to test the ability of iron-oxidizing bacteria to grow using iron meteorites as their source of energy. here we report the growth of two acidophilic iron-oxidizing bacteria, leptospirillum ferrooxidans and acidithiobacillus ferrooxidans, on a piece of the toluca meteorite as ...200515941383
genome-directed isolation of the key nitrogen fixer leptospirillum ferrodiazotrophum sp. nov. from an acidophilic microbial community.analysis of assembled random shotgun sequence data from a low-diversity, subsurface acid mine drainage (amd) biofilm revealed a single nif operon. this was found on a genome fragment belonging to a member of leptospirillum group iii, a lineage in the nitrospirae phylum with no cultivated representatives. based on the prediction that this organism is solely responsible for nitrogen fixation in the community, we pursued a selective isolation strategy to obtain the organism in pure culture. an amd ...200516204553
bioleaching of sulfidic tailing samples with a novel, vacuum-positive pressure driven bioreactor.this study presents a design for a novel bioreactor that uses alternating vacuum and positive pressure cycles to transfer acidic leach solution in and out of contact with finely ground sulfidic mine tailings. these tailings constitute an environmental problem that needs experimental data to support the development of management and control strategies. a conventional stirred tank bioreactor was used as a reference system. both bioreactors were inoculated with mixed cultures of acidophilic iron an ...200516245345
isolation, sequence analysis, and comparison of two plasmids (28 and 29 kilobases) from the biomining bacterium leptospirillum ferrooxidans atcc 49879.two plasmids, of 28,878 bp and 28,012 bp, were isolated from leptospirillum ferrooxidans atcc 49879. altogether, a total of 67 open reading frames (orfs) were identified on both plasmids, of which 32 had predicted products with high homology to proteins of known function, while 11 orfs had predicted products with homology to previously identified proteins of unknown function. twenty-four orfs had products with no homologues in the genbank/ncbi database. an analysis of the orfs and other features ...200516269793
ferric iron reduction by acidophilic heterotrophic bacteria.fifty mesophilic and five moderately thermophilic strains of acidophilic heterotrophic bacteria were tested for the ability to reduce ferric iron in liquid and solid media under aerobic conditions; about 40% of the mesophiles (but none of the moderate thermophiles) displayed at least some capacity to reduce iron. both rates and extents of ferric iron reduction were highly strain dependent. no acidophilic heterotroph reduced nitrate or sulfate, and (limited) reduction of manganese(iv) was noted i ...199116348395
existence of a hydrogen sulfide:ferric ion oxidoreductase in iron-oxidizing bacteria.the existence of a hydrogen sulfide:ferric ion oxidoreductase, which catalyzes the oxidation of elemental sulfur with ferric ions as an electron acceptor to produce ferrous and sulfite ions, was assayed with washed intact cells and cell extracts of various kinds of iron-oxidizing bacteria, such as thiobacillus ferrooxidans 13598, 13661, 14119, 19859, 21834, 23270, and 33020 from the american type culture collection, leptospirillum ferrooxidans 2705 and 2391 from the deutsche sammlung von mikroor ...199216348640
evaluation of leptospirillum ferrooxidans for leaching.the importance of leptospirillum ferrooxidans for leach processes has been evaluated by studying the lithotrophic flora of three mine biotopes and a heap leaching operation, by percolation experiments with inoculated, sterilized ore, and by morphological, physiological, and genetic investigations of pure and mixed cultures of l. ferrooxidans, thiobacillus ferrooxidans, and thiobacillus thiooxidans. in biotopes of 20 degrees c or above, leptospirillum-like bacteria are as abundant as t. ferrooxid ...199216348642
sensitivity of iron-oxidizing bacteria, thiobacillus ferrooxidans and leptospirillum ferrooxidans, to bisulfite ion.when grown on iron-salt medium supplemented with the bisulfite ion, leptospirillum ferrooxidans was much more sensitive to the ion than was thiobacillus ferrooxidans. the causes of the sensitivity of l. ferrooxidans to the bisulfite ion were studied. the bisulfite ion completely inhibited the iron-oxidizing activities of l. ferrooxidans and t. ferrooxidans at 0.02 and 0.2 mm, respectively. a trapping reagent for the bisulfite ion, formaldehyde, completely reversed the inhibition. the treatment o ...199416349199
extracellular polymeric substances mediate bioleaching/biocorrosion via interfacial processes involving iron(iii) ions and acidophilic bacteria.extracellular polymeric substances seem to play a pivotal role in biocorrosion of metals and bioleaching, biocorrosion of metal sulfides for the winning of precious metals as well as acid rock drainage. for better control of both processes, the structure and function of extracellular polymeric substances of corrosion-causing or leaching bacteria are of crucial importance. our research focused on the extremophilic bacteria acidithiobacillus ferrooxidans and leptospirillum ferrooxidans, because of ...200616431087
rapid specific detection and quantification of bacteria and archaea involved in mineral sulfide bioleaching using real-time pcr.a sybrgreen real-time pcr assay was developed to detect and quantify both total and selected 16s rdna species of bacteria and archaea involved in the bioleaching of metals from sulfide ores. a set of specific and universal primers based on 16s rdna sequences was designed and validated for specific detection and quantification of dna isolated from representative strains of acidianus brierleyi, sulfolobus sp., sulfobacillus thermosulfidooxidans, sulfobacillus acidophilus, acidithiobacillus caldus, ...200616508994
resistance determinants of a highly arsenic-resistant strain of leptospirillum ferriphilum isolated from a commercial biooxidation tank.two sets of arsenic resistance genes were isolated from the highly arsenic-resistant leptospirillum ferriphilum fairview strain. one set is located on a transposon, tnlfars, and is related to the previously identified tnatcars from acidithiobacillus caldus isolated from the same arsenopyrite biooxidation tank as l. ferriphilum. tnlfars conferred resistance to arsenite and arsenate and was transpositionally active in escherichia coli. tnlfars and tnatcars were sufficiently different for them not ...200616517682
direct 5s rrna assay for monitoring mixed-culture bioprocesses.this study demonstrates the efficacy of a direct 5s rrna assay for the characterization of mixed microbial populations by using as an example the bacteria associated with acidic mining environments. the direct 5s rrna assay described herein represents a nonselective, direct molecular method for monitoring and characterizing the predominant, metabolically active members of a microbial population. the foundation of the assay is high-resolution denaturing gradient gel electrophoresis (dgge), which ...199616535333
sulfur chemistry in bacterial leaching of 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 ...199616535406
chemolithotrophic bacteria in copper ores leached at high sulfuric acid concentration.extensive bacterial growth was observed when copper sulfide ores were leached with 0.6 n sulfuric acid. the bacterial population developed in this condition was examined by characterization of the spacer regions between the 16s and 23s rrna genetic loci obtained after pcr amplification of the dna extracted from the leached ore. the spacers observed had the sizes found in strains of "leptospirillum ferrooxidans" and thiobacillus thiooxidans, except for a larger one, approximately 560 bp long, tha ...199716535497
bacterial community in copper sulfide ores inoculated and leached with solution from a commercial-scale copper leaching plant.most copper bioleaching plants operate with a high concentration of sulfate salts caused by the continuous addition of sulfuric acid and the recycling of the leaching solution. since the bacteria involved in bioleaching have been generally isolated at low sulfate concentrations, the bacterial population in ores leached with the high-sulfate solution (1.25 m) employed in a copper production plant was investigated. the complexity of the original population was assessed by the length pattern of the ...199716535570
acidophilic microbial communities catalyzing sludge bioleaching monitored by fluorescent in situ hybridization.biological autotrophic sulfur oxidation processes have been proposed to remove heavy metals from wastewater treatment sludge by bioleaching. we made a characterization of the microbial population in batch and continuous sludge bioleaching reactors using fluorescent in situ hybridization of fluorescently-labeled oligonucleotidic probes targeting rrna in a 'top to bottom approach'. batch incubations of sludge with 0.2% (w/v) elemental sulfur resulted in a ph value of 5. alpha-proteobacteria hybrid ...200616622787
amplification of low quantity bacterial rna for microarray studies: time-course analysis of leptospirillum ferrooxidans under nitrogen-fixing conditions.we have developed a method for the amplification of low quantity total bacterial rna for dna microarrays analysis. current methods are based on the linear amplification by the in vitro transcription from the t7 promoter, similar to that used for eukaryotic mrna amplification. for the incorporation of t7 promoter, the prokaryotic rna must be enzymatically modified for the incorporation of a polya tail at the 3' end to emulate the eukaryotic mrna. the method we describe and validate herein avoids ...200616689727
microbial populations identified by fluorescence in situ hybridization in a constructed wetland treating acid coal mine drainage.microorganisms are an integral part of the biogeochemical processes in wetlands, yet microbial communities in sediments within constructed wetlands receiving acid mine drainage (amd) are only poorly understood. the purpose of this study was to characterize the microbial diversity and abundance in a wetland receiving amd using fluorescence in situ hybridization (fish) analysis. seasonal samples of oxic surface sediments, comprised of fe(iii) precipitates, were collected from two treatment cells o ...200616825452
biomodification of coal to remove mercury.a biological process for removal of mercury from coal is under investigation. iron and sulfur oxidizing bacteria have previously been used for desulfurization of coal and for mineral mining. we have shown that removal of mercury from coal is also possible via the same principles. two pure cultures, leptospirillum ferrooxidans and acidithiobacillus ferrooxidans and four environmental consortium samples obtained from an acid mine drainage site were studied for mercury removal from coal. four diffe ...200616915698
cultivation-dependent and cultivation-independent characterization of the microbial community in acid mine drainage associated with acidic pb/zn mine tailings at lechang, guangdong, china.cultivation-based and molecular approaches were used to characterize the phylogenetic composition and structure of the microbial community in an extremely acidic (ph 2.0) acid mine drainage (amd) associated with pb/zn mine tailings that were undergoing vigorous acid generation. acidophilic bacteria were isolated and enumerated on solid media, and were found to be restricted to isolates related to acidithiobacillus ferrooxidans and acidiphilium cryptum. by contrast, cloning and phylogenetic analy ...200717059483
novel bacterial sulfur oxygenase reductases from bioreactors treating gold-bearing concentrates.the microbial community and sulfur oxygenase reductases of metagenomic dna from bioreactors treating gold-bearing concentrates were studied by 16s rrna library, real-time polymerase chain reaction (rt-pcr), conventional cultivation, and molecular cloning. results indicated that major bacterial species were belonging to the genera acidithiobacillus, leptospirillum, sulfobacillus, and sphingomonas, accounting for 6.3, 66.7, 18.8, and 8.3%, respectively; the sole archaeal species was ferroplasma sp ...200717111141
mineral and iron oxidation at low temperatures by pure and mixed cultures of acidophilic enrichment culture from a boreal sulfide mine environment containing a low-grade polymetallic ore was tested in column bioreactors for simulation of low temperature heap leaching. pcr-denaturing gradient gel electrophoresis and 16s rrna gene sequencing revealed the enrichment culture contained an acidithiobacillus ferrooxidans strain with high 16s rrna gene similarity to the psychrotolerant strain ss3 and a mesophilic leptospirillum ferrooxidans strain. as the mixed culture contained a strain ...200717187443
kinetics of iron oxidation by leptospirillum ferriphilum dominated culture at ph below one.the kinetics of ferrous iron oxidation by leptospirillum ferriphilum (l. ferriphilum) dominated culture was studied in the concentration range of 0.1-20 g fe(2+)/l and the effect of ferric iron (0-60 g fe(3+)/l) on fe(2+) oxidation was investigated at ph below one. denaturing gradient gel electrophoresis of pcr amplified 16s rrna genes followed by partial sequencing confirmed that the bacterial community was dominated by l. ferriphilum. in batch assays, fe(2+) oxidation started without lag phase ...200717187444
microbial communities in a porphyry copper tailings impoundment and their impact on the geochemical dynamics of the mine waste.the distribution and diversity of acidophilic bacteria of a tailings impoundment at the la andina copper mine, chile, was examined. the tailings have low sulfide (1.7% pyrite equivalent) and carbonate (1.4% calcite equivalent) contents and are stratified into three distinct zones: a surface (0-70-80 cm) 'oxidation zone' characterized by low-ph (2.5-4), a 'neutralization zone' (70-80 to 300-400 cm) and an unaltered 'primary zone' below 400 cm. a combined cultivation-dependent and biomolecular app ...200717222129
analysis of environmental transcriptomes by dna this work we investigated the correlations between global gene expression patterns and environmental parameters in natural ecosystems. we studied the preferential gene expression of the iron oxidizer bacterium leptospirillum ferrooxidans to adapt its physiology to changes in the physicochemical parameters in its natural medium. transcriptome analysis by dna microarrays can proportionate an instant picture about the preferential gene expression between two different environmental samples. howe ...200717222143
nickel-resistant determinant from leptospirillum ferriphilum.leptospirillum ferriphilum strain ubk03 isolated from a mine in jiangxi, china, is resistant to ni(2+) (30 to 40 mm). a four-gene nickel resistance cluster was identified and, when transformed into escherichia coli, enabled growth in 6 mm nickel. mutation experiments revealed that the genes ncra, ncrb, and ncrc could confer nickel resistance in escherichia coli, whereas the gene ncry could have a negative effect on nickel resistance.200717293508
actinomycete-like proteasomes in a gram-negative bacterium.cultivation-independent proteogenomic exploration of mine-drainage biofilm has revealed proteasomes in gram-negative bacteria of the nitrospirae phylum (leptospirillum group ii) dominating this acidophilic community. most probably, the proteasome genes were acquired from actinobacteria, the only eubacteria previously known to contain proteasomes. in addition, this study shows that the proteasome and the evolutionarily related atp-dependent protease hslvu (also known as clpqy) are not mutually ex ...200717587582
modeling of ferrous iron oxidation by a leptospirillum ferrooxidans-dominated chemostat culture.the objective of this study was to evaluate a direct classical bioengineering approach to model data generated from continuous bio-oxidation of fe(2+) by a leptospirillum ferrooxidans-dominated culture fed with either 9 g or 18 g fe(2+) l(-1) under chemostat conditions (dilution rates were between 0.051 and 0.094 h(-1)). the basic monod and pirt equations have successfully been integrated in an overall mass balance procedure, which has not been previously presented in this detail for fe(2+) oxid ...200817615557
[bacterial diversity analysis of moderately thermophilic microflora enriched by different energy sources].bacterial biodiversities of three moderately thermophilic bioleaching microfloras grown at 50 degrees c on media with pyrite, chalcopyrite, and pure ferrous iron supplemented with sulfur as energy sources were investigated respectively. the 16s rrna genes of the microorganisms in the cultures flasks were pcr amplified and cloned to identify the bacterial species by comparative sequence analysis, the structural differences of microfloras enriched by different energy sources were compared. a total ...200717672291
rapidly evolving crisprs implicated in acquired resistance of microorganisms to viruses.recent experimental evidence has demonstrated that bacteria acquire resistance to viruses by incorporation of short transcribed nucleotide sequences into regions of clustered regularly interspaced short palindromic repeats (crispr). we have analysed community genomic data from acidophilic microbial biofilms and discovered that evolution of the crispr regions in two distinct leptospirillum group ii bacteria occurs fast enough to promote individuality in otherwise nearly clonal populations. compar ...200817894817
microbial populations in acid mineral bioleaching systems of tong shankou copper mine, understand the composition and structure of microbial communities in different acid mineral bioleaching systems, and to present a more complete picture of microbially mediated acid mine drainage production.200717897227
prokaryotic community composition and ecology of floating macroscopic filaments from an extreme acidic environment, río tinto (sw, spain).the prokaryotic diversity of macroscopic filaments located at the water surface in an extreme acidic environment, río tinto (sw, spain), has been analysed through denaturing gradient gel electrophoresis (dgge), cloning of 16s rrna genes and fluorescence in situ hybridization (fish). the dominant species present in the macrofilaments were acidithiobacillus ferrooxidans, leptospirillum ferrooxidans and acidiphilium spp., which represented the three main bacterial genera found in the water column o ...200717950555
molecular diversity of 16s rrna and gyrb genes in copper mines.the molecular diversities of the microbial communities from four sites impacted by acid mine drainage (amd) at dexing copper mine in jiangxi province of china were studied using 16s rrna sequences and gyrb sequences. of the four sampled sites, each habitat exhibited distinct geochemical characteristics and the sites were linked geographically allowing us to correlate microbial community structure to geochemical characteristics. in the present study, we examined the molecular diversity of 16s rrn ...200817957354
"bioshrouding": a novel approach for securing reactive mineral tailings.a novel technique ("bioshrouding") for safeguarding highly reactive sulfidic mineral tailings deposits is proposed. in this, freshly milled wastes are colonised with ferric iron-reducing heterotrophic acidophilic bacteria that form biofilms on reactive mineral surfaces, thereby preventing or minimising colonisation by iron sulfide-oxidising chemolithotrophs such as acidithiobacillus ferrooxidans and leptospirillum spp. data from initial experiments showed that dissolution of pyrite could be redu ...200817975731
comparison of ferric iron generation by different species of acidophilic bacteria immobilized in packed-bed reactors.flooded packed-bed bioreactors, prepared by immobilizing four different species of acidophilic iron-oxidizing bacteria on porous glass beads, were compared for their ferric iron-generating capacities when operated in batch and continuous flow modes over a period of up to 9 months, using a ferrous iron-rich synthetic liquor and acid mine drainage (amd) water. the bacteria used were strains of acidithiobacillus ferrooxidans, leptospirillum ferrooxidans, a ferrimicrobium-like isolate (tstr) and a n ...200817983721
microbial diversity of mine water at zhong tiaoshan copper mine, china.microbial diversity of mine water at zhong tiaoshan copper mine, shanxi province, china, was analyzed using a culture-independent 16s rrna gene (rdna) based on cloning approach. a total of 59 operational taxonomic units (otus) were obtained from 226 clones from all three samples (8 otus from sample sx1, 25 from sx2 and 26 from sx3). 46 of them were representative otus and were sequenced. 93.5% of the total clones had sequences that were less than 5% difference from those in the nucleic acids dat ...200718072249
thermodynamic and kinetic characterization using process dynamics: acidophilic ferrous iron oxidation by leptospirillum ferrooxidans.kinetic and stoichiometric properties of acidophilic aerobic ferrous iron oxidation by growing and non-growing leptospirillum ferrooxidans cultures were investigated. the use of a continuous stirred tank reactor operated at a variable dilution rate and equipped with on-line measurement of the electron donor, acceptor and anabolic substrate uptake rate enabled detailed kinetic characterization from a single experiment. it was demonstrated that substrate conversion and microbial growth are tightly ...200818080344
microbial diversity in acid mineral bioleaching systems of dongxiang copper mine and yinshan lead-zinc understand the composition and structure of microbial communities in acid mineral bioleaching systems, the molecular diversity of 16s rdna genes was examined using a pcr-based cloning approach. a total of 31 operational taxonomic units (otus) were obtained from the four samples taken from four different bioleaching sites in yinshan lead-zinc mine and dongxiang copper mine in jiangxi province, china. the percentages of overlapping otus between sites ranged from 22.2 to 50.0%. phylogenetic anal ...200818157706
selection of leptospirillum ferrooxidans srpcbl and development for enhanced ferric regeneration in stirred tank and airlift column reactor.presence of leptospirillum ferrooxidans plays significant role in ferric sulphate generation during bioleaching process. thus, an attempt was made to select l. ferrooxidans from the polymetallic concentrate leachate and further developed it for enhanced ferric iron regeneration from the leachate in shake flask, stirred tank and column reactor. when ferric to ferrous iron ratio in the shake flask reached to 20:1, l. ferrooxidans out competed acidithiobacillus ferrooxidans and accounted for more t ...200818325759
isolation and characterization of ferroplasma thermophilum sp. nov., a novel extremely acidophilic, moderately thermophilic archaeon and its role in bioleaching of isolate ferroplasma thermophilum l1(t) from a low ph environment and to understand its role in bioleaching of chalcopyrite.200818422958
microbiological and geochemical dynamics in simulated-heap leaching of a polymetallic sulfide ore.the evolution of microbial populations involved in simulated-heap leaching of a polymetallic black schist sulfide ore (from the recently-commissioned talvivaara mine, finland) was monitored in aerated packed bed column reactors over a period of 40 weeks. the influence of ore particle size (2-6.5 mm and 6.5-12 mm) on changes in composition of the bioleaching microflora and mineral leaching dynamics in columns was investigated and compared to fine-grain (<2 microm) ore that was bioprocessed in sha ...200818496880
culturable and molecular phylogenetic diversity of microorganisms in an open-dumped, extremely acidic pb/zn mine tailings.a combination of cultivation-based and molecular-based approaches was used to reveal the culturable and molecular diversity of the microbes inhabiting an open-dumped pb/zn mine tailings that was undergoing intensive acid generation (ph 1.9). culturable bacteria found in the extremely acidic mine tailings were acidithiobacillus ferrooxidans, leptospirillum ferriphilum, sulfobacillus thermotolerans and acidiphilium cryptum, where the number of acidophilic heterotrophs was ten times higher than tha ...200818512002
biomodification of coal to remove mercury.a biological process for removal of mercury from coal is under investigation. iron and sulfur oxidizing bacteria have previously been used for desulfurization of coal and for mineral mining. we have shown that removal of mercury from coal is also possible via the same principles. two pure cultures, leptospirillum ferrooxidans and acidithiobacillus ferrooxidans and four environmental consortium samples obtained from an acid mine drainage site were studied for mercury removal from coal. four diffe ...200618563664
quantitative microbial community analysis of three different sulfidic mine tailing dumps generating acid mine drainage.the microbial communities of three different sulfidic and acidic mine waste tailing dumps located in botswana, germany, and sweden were quantitatively analyzed using quantitative real-time pcr (q-pcr), fluorescence in situ hybridization (fish), catalyzed reporter deposition-fish (card-fish), sybr green ii direct counting, and the most probable number (mpn) cultivation technique. depth profiles of cell numbers showed that the compositions of the microbial communities are greatly different at the ...200818586975
population genomic analysis of strain variation in leptospirillum group ii bacteria involved in acid mine drainage formation.deeply sampled community genomic (metagenomic) datasets enable comprehensive analysis of heterogeneity in natural microbial populations. in this study, we used sequence data obtained from the dominant member of a low-diversity natural chemoautotrophic microbial community to determine how coexisting closely related individuals differ from each other in terms of gene sequence and gene content, and to uncover evidence of evolutionary processes that occur over short timescales. dna sequence obtained ...200818651792
bioleaching of chalcopyrite concentrate by a moderately thermophilic culture in a stirred tank reactor.a mixed culture of moderately thermophilic microorganisms was enriched from acid mine drainage samples collected from several chalcopyrite mines in china. such mixed culture can be used to effectively extract copper from chalcopyrite. furthermore, after being adapted to gradually increased concentration of chalcopyrite concentrate, the tolerance of the mixed culture to chalcopyrite concentrate was brought up to 80 g/l. the effects of several leaching parameters on copper recovery in stirred tank ...200918657418
proteomics-inferred genome typing (pigt) demonstrates inter-population recombination as a strategy for environmental adaptation.analyses of ecological and evolutionary processes that shape microbial consortia are facilitated by comprehensive studies of ecosystems with low species richness. in the current study we evaluated the role of recombination in altering the fitness of chemoautotrophic bacteria in their natural environment. proteomics-inferred genome typing (pigt) was used to genotype the dominant leptospirillum group ii populations in 27 biofilms sampled from six locations in the richmond mine acid mine drainage s ...200918826438
natural acidophilic biofilm communities reflect distinct organismal and functional organization.pellicle biofilms colonize the air-solution interface of underground acid mine drainage (amd) streams and pools within the richmond mine (iron mountain, redding, ca, usa). they exhibit relatively low species richness and, consequently, represent good model systems to study natural microbial community structure. fluorescence in situ hybridization combined with epifluorescent microscopy and transmission electron microscopy revealed spatially and temporally defined microbial assemblages. leptospiri ...200918843299
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 ...200819025650
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