| biological extraction of realgar by acidithiobacillus ferrooxidans and its in vitro and in vivo antitumor activities. | acidithiobacillus ferrooxidans is a gram-negative, chemolithoautotrophic bacterium involved in metal bioleaching. it is used for the extraction of coarse medical realgar, which is converted into an aqueous solution. to prove its feasibility as an anticancer drug candidate, extracted realgar (er/af) was evaluated for its antitumor activities both in vitro and in vivo. in cytotoxicity tests, er/af displayed significant inhibition on cell proliferation of hepg2, smmc7721, and h22 cells in a time an ... | 2010 | 20645754 |
| electrochemical growth of acidithiobacillus ferrooxidans on a graphite electrode for obtaining a biocathode for direct electrocatalytic reduction of oxygen. | an aspect in microbial fuel cell research that is currently of great interest is the development of bacterial cathodes. bacterial cathodes that catalyze oxygen reduction to water at low ph have the advantage of overcoming the kinetic limitations due to the requirement of 4 protons per molecule reduced. in this work we have studied the performance of a biocathode using as electrocatalyst an acidophile microorganism: acidithiobacillus ferrooxidans. growth of the microorganism directly on the elect ... | 2010 | 20678913 |
| insights into the dynamics of bacterial communities during chalcopyrite bioleaching. | the microbial ecology of the bioleaching of chalcopyrite ores is poorly understood and little effort has been made to handle the microbiological components of these processes. in this study, the composition and structure of microbial communities in acid mineral bioleaching systems have been studied using a pcr-based cloning approach. denaturing gradient gel electrophoresis (dgge) analysis of pcr-amplified 16s rrna gene fragments from bacteria was used to evaluate the changes in the bacterial com ... | 2010 | 20698885 |
| pdms-based porous particles as support beds for cell immobilization: bacterial biofilm formation as a function of porosity and polymer composition. | the objective of this work is to test the performance of new synthetic polydimethylsiloxane (pdms)-based bed particles acting as carriers for bacteria biofilms. the particles obtained have a highly interconnected porous structure which offers a large surface adsorption area to the bacteria. in addition, pdms materials can be cross-linked by copolymerization with other polymers. in the present work we have chosen two hydrophilic polymers: xanthan gum polysaccharide and tetraethoxysilane (teos). t ... | 2010 | 20702072 |
| genes and pathways for co2 fixation in the obligate, chemolithoautotrophic acidophile, acidithiobacillus ferrooxidans, carbon fixation in a. ferrooxidans. | acidithiobacillus ferrooxidans is chemolithoautotrophic γ-proteobacterium that thrives at extremely low ph (ph 1-2). although a substantial amount of information is available regarding co2 uptake and fixation in a variety of facultative autotrophs, less is known about the processes in obligate autotrophs, especially those living in extremely acidic conditions, prompting the present study. | 2010 | 20799944 |
| membrane fluidity and fatty acid comparisons in psychrotrophic and mesophilic strains of acidithiobacillus ferrooxidans under cold growth temperatures. | psychrotrophic strains of acidithiobacillus ferrooxidans have an important role in metal leaching and acid mine drainage (amd) production in colder mining environments. we investigated cytoplasmic membrane fluidity and fatty acid alterations in response to low temperatures (5 and 15°c). significant differences in membrane fluidity, measured by polarization (p) of 1,6-diphenyl-1,3,5-hexatriene (dph), were found where the psychrotrophic strains had a significantly more rigid membrane (p range = 0. ... | 2010 | 20852847 |
| "isolation, identification, characterization and polymetallic concentrate leaching studies of tryptic soy- and peptone-resistant thermotolerant acidithiobacillus ferrooxidans srdsm2". | acidithiobacillus ferrooxidans strain srdsm2 was isolated from silica containing soil sample collected at a rajpardi lignite mine. the strain responded to the addition of 0.5 g/l peptone and 1.0 g/l tryptone soya broth in the ferrous sulphate tryptone soya broth (itsb) medium with 35.3% and 29.6% increase in iron oxidation rate (ior), but decrease in the ior at higher peptone or tryptone soya broth levels. the presence of 4 mm of zinc as zinc sulphate in the medium increased the ior by 24.4%. fo ... | 2010 | 20863700 |
| effects of cell condition, ph, and temperature on lead, zinc, and copper sorption to acidithiobacillus caldus strain bc13. | this study describes the effects of cell condition, ph, and temperature on lead, zinc, and copper sorption to acidithiobacillus caldus strain bc13 with a langmuir model. copper exhibited the highest loading capacity, 4.76 ± 0.28 mmol g(-1), to viable cells at ph 5.5. the highest k(l) (binding-site affinity) observed was 61.2 ± 3.0 l mmol(-1) to dehydrated cells at ph 4.0. the phs that maximized loading capacities and binding-site affinities were generally between 4.0 and 5.5, where the sum of fr ... | 2010 | 20884118 |
| phylogenetic and genetic variation among fe(ii)-oxidizing acidithiobacilli supports the view that these comprise multiple species with different ferrous iron oxidation pathways. | autotrophic acidophilic iron- and sulfur-oxidizing bacteria of the genus acidithiobacillus constitute a heterogeneous taxon encompassing a high degree of diversity at the phylogenetic and genetic levels, though currently only two species are recognized (acidithiobacillus ferrooxidans and acidithiobacillus ferrivorans). one of the major functional disparities concerns the biochemical mechanisms of iron and sulfur oxidation, with discrepancies reported in the literature concerning the genes and pr ... | 2010 | 20884692 |
| relationship between bioleaching performance, bacterial community structure and mineralogy in the bioleaching of a copper concentrate in stirred-tank reactors. | during the bioshale european project, a techno-economic study of the bioleaching of a copper concentrate originating from a black shale ore was carried out. this concentrate is a multi-mineral resource in which the copper sulphides are mainly chalcocite, covellite, bornite and chalcopyrite. the experiments undertaken to produce the techno-economic data were also an opportunity to carry out more fundamental research. the objective of this work was to combine the results of the bioleaching experim ... | 2010 | 20890755 |
| effects of ferrous sulfate, inoculum history, and anionic form on lead, zinc, and copper toxicity to acidithiobacillus caldus strain bc13. | the current study reports the single and combined toxicities of pb, zn, and cu to acidithiobacillus caldus strain bc13. the observed half-maximal inhibitory concentrations (ic50), ± 95% confidence intervals, for pb, zn, and cu were 0.9 ± 0.1 mm, 39 ± 0.5 mm, and 120 ± 8 mm, respectively. the observed minimum inhibitory concentrations (mic) for pb, zn, and cu were 7.5 mm, 75 mm, and 250 mm, respectively. when metals were presented in binary mixtures, the toxicities were less than additive. for ex ... | 2010 | 20931606 |
| expression, purification, and characterization of an iron chaperon protein cyay from acidithiobacillus ferrooxidans. | cyay is the bacterial homolog of frataxin, proposed to be involved in the assembly of iron-sulfur clusters. while, the physiological iron donor for the iron-sulfur clusters assembly remains controversial. in this study, the gene of cyay from acidithiobacillus ferrooxidans was cloned and expressed in escherichia coli, the protein was purified by one-step affinity chromatography to homogeneity. the cyay protein can bind ferric iron and serve as an iron donor for the biogenesis of iron-sulfur clust ... | 2011 | 20957368 |
| ecophysiology of fe-cycling bacteria in acidic sediments. | using a combination of cultivation-dependent and -independent methods, this study aimed to elucidate the diversity of microorganisms involved in iron cycling and to resolve their in situ functional links in sediments of an acidic lignite mine lake. using six different media with ph values ranging from 2.5 to 4.3, 117 isolates were obtained that grouped into 38 different strains, including 27 putative new species with respect to the closest characterized strains. among the isolated strains, 22 st ... | 2010 | 20971876 |
| a feasibility study on bioelectrokinetics for the removal of heavy metals from tailing soil. | the combination of bioremediation and electrokinetics, termed bioelectrokinetics, has been studied constantly to enhance the removal of organic and inorganic contaminants from soil. the use of the bioleaching process originating from fe- and/or s-oxidizing bacteria may be a feasible technology for the remediation of heavy metal-contaminated soils. in this study, the bioleaching process driven by injection of s-oxidizing bacteria, acidithiobacillus thiooxidans, was evaluated as a pre-treatment st ... | 2010 | 21046430 |
| extraction of manganese from electrolytic manganese residue by bioleaching. | extraction of manganese from electrolytic manganese residues using bioleaching was investigated in this paper. the maximum extraction efficiency of mn was 93% by sulfur-oxidizing bacteria at 4.0 g/l sulfur after bioleaching of 9days, while the maximum extraction efficiency of mn was 81% by pyrite-leaching bacteria at 4.0 g/l pyrite. the series bioleaching first by sulfur-oxidizing bacteria and followed by pyrite-leaching bacteria evidently promoted the extraction of manganese, witnessing the max ... | 2010 | 21050747 |
| sulfite oxidation catalyzed by aa(3)-type cytochrome c oxidase in acidithiobacillus ferrooxidans. | sulfite is produced as a toxic intermediate during acidithiobacillus ferrooxidans sulfur oxidation. a. ferrooxidans d3-2, which posseses the highest copper bioleaching activity, is more resistant to sulfite than other a. ferrooxidans strains, including atcc 23270. when sulfite oxidase was purified homogeneously from strain d3-2, the oxidized and reduced forms of the purified sulfite oxidase absorption spectra corresponded to those of a. ferrooxidans aa(3)-type cytochrome c oxidase. the confirmed ... | 2010 | 21071859 |
| metabolic changes of acidithiobacillus caldus under cu²(+) stress. | metabolic changes were investigated by measuring the depletion of dissolved oxygen and the enzymatic activities of sulfur metabolism in acidithiobacillus caldus (a. caldus) before and after copper stress. the results showed that high concentrations of cu²(+) have an indirect negative effect on the sulfite oxidase and the aps reductase involved in sulfur metabolism when a. caldus is cultured in medium with elemental sulfur as its growth energy. this leads to a decrease in the respiration rate and ... | 2010 | 21072861 |
| heavy metal removal from shooting range soil by hybrid electrokinetics with bacteria and enhancing agents. | this study presents a method for heavy metal removal from a shooting range soil by a newly suggested hybrid technology. active bioaugmentation was performed using acidithiobacillus thiooxidans in the bioleaching step, and each test was sequentially combined with acid-enhanced and edta-enhanced electrokinetics. the results of the bioleaching processes indicated that s-oxidizing bacteria enhanced the mobility of heavy metals in the soil, based on their chemical forms. this process improved the fin ... | 2010 | 21090604 |
| application of a depositional facies model to an acid mine drainage site. | lower red eyes is an acid mine drainage site in pennsylvania where low-ph fe(ii) oxidation has created a large, terraced iron mound downstream of an anoxic, acidic, metal-rich spring. aqueous chemistry, mineral precipitates, microbial communities, and laboratory-based fe(ii) oxidation rates for this site were analyzed in the context of a depositional facies model. depositional facies were defined as pools, terraces, or microterracettes based on cm-scale sediment morphology, irrespective of the d ... | 2010 | 21097582 |
| effects of chloride acclimation on iron oxyhydroxides and cell morphology during cultivation of acidithiobacillus ferrooxidans. | iron oxyhydroxides as the efficient scavengers for heavy metals have been extensively investigated in iron-rich acid sulfate waters in the presence of acidithiobacillus ferrooxidans (a. ferrooxidans, an especially important chemolithoautotroph for bioleaching and desulfurization of coal). in this study, we observed the morphology and elemental composition of cells in stationary phase and examined the dynamic variation of iron oxyhydroxides produced in cultures of a. ferrooxidans incubated in mod ... | 2010 | 21128632 |
| ferric iron uptake genes are differentially expressed in the presence of copper sulfides in acidithiobacillus ferrooxidans strain lr. | acidithiobacillus ferrooxidans is one of the most widely used microorganisms in bioleaching operations to recover copper from low-grade copper sulfide ores. this work aimed to investigate the relative expression of genes related to the iron uptake system when a. ferrooxidans lr was maintained in contact with chalcopyrite or bornite as the sole energy source. real-time quantitative pcr analysis revealed that the presence of bornite had no effect on the expression of seven genes related to the sid ... | 2010 | 21132364 |
| bioleaching of realgar by acidithiobacillus ferrooxidans using ferrous iron and elemental sulfur as the sole and mixed energy sources. | the characteristics of the bioleaching of realgar by acidithiobacillus ferrooxidans by-3 (a. ferrooxidans) were investigated in this work. we examined the effects of using ferrous iron and elemental sulfur as the sole and mixed energy sources on the bioleaching of realgar. under all experimental conditions, a. ferrooxidans by-3 significantly enhanced the dissolution of realgar. moreover, arsenic was more efficiently leached using a. ferrooxidans by-3 in the presence of ferrous iron than in other ... | 2010 | 21146407 |
| acidithiobacillus thiooxidans secretome containing a newly described lipoprotein licanantase enhances chalcopyrite bioleaching rate. | the nature of the mineral-bacteria interphase where electron and mass transfer processes occur is a key element of the bioleaching processes of sulfide minerals. this interphase is composed of proteins, metabolites, and other compounds embedded in extracellular polymeric substances mainly consisting of sugars and lipids (gehrke et al., appl environ microbiol 64(7):2743-2747, 1998). on this respect, despite acidithiobacilli-a ubiquitous bacterial genera in bioleaching processes (rawlings, microb ... | 2010 | 21191788 |
| biofiltration of reduced sulphur compounds and community analysis of sulphur-oxidizing bacteria. | the present work aims to use a two-stage biotrickling filters for simultaneous treatment of hydrogen sulphide (h(2)s), methyl mercaptan (mm), dimethyl sulphide (dms) and dimethyl disulphide (dmds). the first biofilter was inoculated with acidithiobacillus thiooxidans (bat) and the second one with thiobacillus thioparus (btt). for separate feeds of reduced sulphur compounds (rsc), the elimination capacity (ec) order was dmds>dms>mm. the ec values were 9.8 g(mm-s)/m(3)/h (btt; 78% removal efficien ... | 2010 | 21216139 |
| cellular levels of heme affect the activity of dimeric glutamyl-trna reductase. | glutamyl-trna reductase (glutr) is the first enzyme committed to tetrapyrrole biosynthesis by the c(5)-pathway. this enzyme transforms glutamyl-trna into glutamate-1-semi-aldehyde, which is then transformed into 5-amino levulinic acid by the glutamate-1-semi-aldehyde 2,1-aminomutase. binding of heme to glutr seems to be relevant to regulate the enzyme function. recombinant glutr from acidithiobacillus ferrooxidans an acidophilic bacterium that participates in bioleaching of minerals was expresse ... | 2011 | 21219871 |
| adsorptive removal of as(iii) by biogenic schwertmannite from simulated as-contaminated groundwater. | this study investigates synthesis of biogenic schwertmannite by acidithiobacillus ferrooxidans and its role and mechanism in adsorption of as(iii) from water. results indicate that schwertmannite particles formed through oxidation of ferrous sulfate by a. ferrooxidans cells for different times vary greatly in size and in morphology. the hedge-hog like schwertmannite formed after reaction for 72h are aggregative spheroid particles with a diameter of approximately 2.5µm and its chemical formula ca ... | 2011 | 21239041 |
| construction of recombinant mercury resistant acidithiobacillus caldus. | a mercury-resistant plasmid of ptmj212 which was able to shuttle between acidithiobacillus caldus and escherichia coli was constructed by inserting the mercury resistant determinants, the mer operon of acidithiobacillus ferrooxidans, into the incq plasmid of pjrd215. ptmj212 was transferred from escherichia coli into acidithiobacillus caldus through conjugation. furthermore, ptmj212 was transferred back from acidithiobacillus caldus into escherichia coli, thereby confirming the initial transfer ... | 2011 | 21239150 |
| dynamic of active microorganisms inhabiting a bioleaching industrial heap of low-grade copper sulfide ore monitored by real-time pcr and oligonucleotide prokaryotic acidophile microarray. | the bioleaching of metal sulfide has developed into a very important industrial process and understanding the microbial dynamic is key to advancing commercial bioleaching operations. here we report the first quantitative description of the dynamic of active communities in an industrial bioleaching heap. acidithiobacillus ferrooxidans was the most abundant during the first part of the leaching cycle, while the abundance of leptospirillum ferriphilum and ferroplasma acidiphilum increased with age ... | 2009 | 21255296 |
| zinc and lead leaching from contaminated industrial waste sludges using coupled processes. | metal pollution of solid matrices, like soils, sediments and sludge, is widespread across the globe, and the clean-up of these matrices presents many difficulties. the aim of this study was to develop an efficient leaching technique for metal removal from an industrial carbon sludge contaminated with zn (8600 mg kg(-1)) and pb (389 mg kg(-1)). to this end, the possibility of coupling processes, such as extraction with mineral acids, edta addition, ultrasound and bioleaching, was investigated. le ... | 2010 | 21275254 |
| low temperature removal of inorganic sulfur compounds from mining process waters. | process water and effluents from mining operations treating sulfide rich ores often contain considerable concentrations of metastable inorganic sulfur compounds such as thiosulfate and tetrathionate. these species may cause environmental problems if released to downstream recipients due to oxidation to sulfuric acid catalyzed by acidophilic microorganisms. molecular phylogenic analysis of the tailings pond and recipient streams identified psychrotolerant and mesophilic inorganic sulfur compound ... | 2011 | 21280027 |
| differential gene expression in response to copper in acidithiobacillus ferrooxidans strains possessing dissimilar copper resistance. | locus afe_0454 from acidithiobacillus ferrooxidans (at.ferrooxidans) is annotated as related to copper resistance in the institute for genomic research database. in our study, two at.ferrooxidans strains, 26(#) and dc, with different levels of copper ion resistance were isolated from acid mine drainages at two major copper mines in china, and their copper-resistance capacity was determined. the 26(#) strain had a copper-tolerance level of 0.22 mol/l, whereas the dc strain had a lower copper-tole ... | 2010 | 21282905 |
| classification of modern and old río tinto sedimentary deposits through the biomolecular record using a life marker biochip: implications for detecting life on mars. | the particular mineralogy formed in the acidic conditions of the río tinto has proven to be a first-order analogue for the acid-sulfate aqueous environments of mars. therefore, studies about the formation and preservation of biosignatures in the río tinto will provide insights into equivalent processes on mars. we characterized the biomolecular patterns recorded in samples of modern and old fluvial sediments along a segment of the river by means of an antibody microarray containing more than 200 ... | 2011 | 21294642 |
| effects of copper exposure on expression of glutathione-related genes in acidithiobacillus ferrooxidans. | the response of acidithiobacillus ferrooxidans to variations in extracellular cu exposure was investigated in terms of glutathione-related genes expression profiling based on reverse-transcription quantitative pcr analysis. the results show that the higher concentration of cu would induce the expression of glutathione-related enzymes and cells elicited specific transcriptional responses when challenged with environmental cu (0.08 mol l(-1)) conditions over a 60-min period. in comparison to the c ... | 2011 | 21305293 |
| autotrophic, sulfur-oxidizing actinobacteria in acidic environments. | some novel actinobacteria from geothermal environments were shown to grow autotrophically with sulfur as an energy source. these bacteria have not been formally named and are referred to here as "acidithiomicrobium" species, as the first of the acidophilic actinobacteria observed to grow on sulfur. they are related to acidimicrobium ferrooxidans with which they share a capacity for ferrous iron oxidation. ribulose bisphosphate carboxylase/oxygenase (rubisco) is active in co(2) fixation by acidim ... | 2011 | 21308384 |
| column bioleaching of uranium embedded in granite porphyry by a mesophilic acidophilic consortium. | a mesophilic acidophilic consortium was enriched from acid mine drainage samples collected from several uranium mines in china. the performance of the consortium in column bioleaching of low-grade uranium embedded in granite porphyry was investigated. the influences of several chemical parameters on uranium extraction in column reactor were also investigated. a uranium recovery of 96.82% was achieved in 97 days column leaching process including 33 days acid pre-leaching stage and 64 days bioleac ... | 2011 | 21316943 |
| characterization of the active bacterial community involved in natural attenuation processes in arsenic-rich creek sediments. | acid mine drainage of the carnoulès mine (france) is characterized by acid waters containing high concentrations of arsenic and iron. in the first 30 m along the reigous, a small creek draining the site, more than 38% of the dissolved arsenic was removed by co-precipitation with fe(iii), in agreement with previous studies, which suggest a role of microbial activities in the co-precipitation of as(iii) and as(v) with fe(iii) and sulfate. to investigate how this particular ecosystem functions, the ... | 2011 | 21318282 |
| geomicrobiology of la zarza-perrunal acid mine effluent (iberian pyritic belt, spain). | effluent from la zarza-perrunal, a mine on the iberian pyrite belt, was chosen to be geomicrobiologically characterized along a 1,200-m stream length. the ph at the origin was 3.1, which decreased to 1.9 at the final downstream sampling site. the total iron concentration showed variations along the effluent, resulting from (i) significant hydrolysis and precipitation of fe(iii) (especially along the first reach of the stream) and (ii) concentration induced by evaporation (mostly in the last reac ... | 2011 | 21357431 |
| assembly mechanism of [fe2s2] cluster in ferredoxin from acidithiobacillus ferrooxidans. | ferredoxin is a typical iron-sulfur protein that is ubiquitous in biological redox systems. this study investigates the in vitro assembly of a [fe2s2] cluster in the ferredoxin from acidithiobacillus ferrooxidans in the presence of three scaffold proteins: isca, iscs, and iscu. the spectra and maldi-tof ms results for the reconstituted ferredoxin confirm that the iron-sulfur cluster was correctly assembled in the protein. the inactivation of cysteine desulfurase by l-allylglycine completely bloc ... | 2011 | 21364293 |
| biodiversity and geochemistry of an extremely acidic, low-temperature subterranean environment sustained by chemolithotrophy. | the geochemical dynamics and composition of microbial communities within a low-temperature (ôê+8.5-¦c), long-abandoned (>ôçâ90 years) underground pyrite mine (cae coch, located in north wales) were investigated. surface water percolating through fractures in the residual pyrite ore body that forms the roof of the mine becomes extremely acidic and iron-enriched due to microbially accelerated oxidative dissolution of the sulfide mineral. water droplets on the mine roof were found to host a very li ... | 2011 | 21382147 |
| [difference in acclimation of acidithiobacillus ferrooxidans by various substrates and its effect on coal desulfurization efficiency]. | in this study, acidithiobacillus ferrooxidans lx5 was cultured in 9k medium with pyrite and ferrous sulfate as the substrates. results showed that the number of a. ferrooxidans lx5 acclimated by pyrite for 20 d was 3.0 x 10(7) cell/ml in the liquid, and the oxidation activity to pyrite was stronger. a. ferrooxidans lx5 cultured for 48 h was 1.0 x 10(8) cell/ml in medium with feso4. extracellular polymeric substance (eps) produced from a. ferrooxidans lx5 acclimated by pyrite was 2 395 microg/(10 ... | 2011 | 21404698 |
| targeting the role of a key conserved motif for substrate selection and catalysis by 3-deoxy-d-manno-octulosonate 8-phosphate synthase. | 3-deoxy-d-manno-octulosonate 8-phosphate synthase (kdo8ps) catalyzes the reaction between three-carbon phosphoenolpyruvate (pep) and five-carbon d-arabinose 5-phosphate (a5p), generating kdo8p, a key intermediate in the biosynthetic pathway to 3-deoxy-d-manno-octulosonate, a component of the lipopolysaccharide of the gram-negative bacterial cell wall. both metal-dependent and metal-independent forms of kdo8ps have been characterized. kdo8ps is evolutionarily and mechanistically related to the fi ... | 2011 | 21438567 |
| growth kinetics of hydrogen sulfide oxidizing bacteria in corroded concrete from sewers. | hydrogen sulfide oxidation by microbes present on concrete surfaces of sewer pipes is a key process in sewer corrosion. the growth of aerobic sulfur oxidizing bacteria from corroded concrete surfaces was studied in a batch reactor. samples of corrosion products, containing sulfur oxidizing bacteria, were suspended in aqueous solution at ph similar to that of corroded concrete. hydrogen sulfide was supplied to the reactor to provide the source of reduced sulfur. the removal of hydrogen sulfide an ... | 2011 | 21440988 |
| different strategies for recovering metals from caron process residue. | the capacity of acidithiobacillus thiooxidans dms 11478 to recover the heavy metals contained in the residue obtained from the caron process has been evaluated. different bioreactor configurations were studied: a two-stage batch system and two semi-continuous systems (stirred-tank reactor leaching and column leaching). in the two-stage system, 46.8% co, 36.0% mg, 26.3% mn and 22.3% ni were solubilised after 6h of contact between the residue and the bacteria-free bioacid. the results obtained wit ... | 2011 | 21466919 |
| characterization of an ompa-like outer membrane protein of the acidophilic iron-oxidizing bacterium, acidithiobacillus ferrooxidans. | an ompa family protein (fopa) previously reported as one of the major outer membrane proteins of an acidophilic iron-oxidizing bacterium acidithiobacillus ferrooxidans was characterized with emphasis on the modification by heat and the interaction with peptidoglycan. a 30-kda band corresponding to the fopa protein was detected in outer membrane proteins extracted at 75°c or heated to 100°c for 10 min prior to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (sds-page). however, the band ... | 2011 | 21472537 |
| uncultured archaea dominate in the thermal groundwater of uzon caldera, kamchatka. | the thermoacidophilic microbial community inhabiting the groundwater with ph 4.0 and temperature 50°c at the east thermal field of uzon caldera, kamchatka, was examined using pyrosequencing of the v3 region of the 16s rrna gene. bacteria comprise about 30% of microorganisms and are represented primarily by aerobic lithoautotrophs using the energy sources of volcanic origin-thermoacidophilic methanotrophs of the phylum verrucomicrobia and acidithiobacillus spp. oxidising metals and reduced sulfur ... | 2011 | 21512891 |
| quorum-sensing system in acidithiobacillus ferrooxidans involved in its resistance to cu(2+). | aims: the purpose of this study was to search for the relationship between quorum sensing (qs) and cu(2+) resistance in acidithiobacillus ferrooxidans. methods and results: resistance to cu(2+) of a. ferrooxidans significantly decreased with the treatment dose of a synthetic qs blocker (5z)-4-bromo-5-(bromomethylene)-2(5h)-furanone (fur). relative differences in expression of the qs genes afei, afer and cu(2+) resistance-associated genes afe0329, afe0454 were examined in the presence of cu(2+) ... | 2011 | 21535043 |
| proteomic insights into cold adaptation of psychrotrophic and mesophilic acidithiobacillus ferrooxidans strains. | cold tolerant strains of acidithiobacillus ferrooxidans play a role in metal leaching and acid mine drainage (amd) production in northern latitude/boreal mining environments. in this study we used a proteomics and bioinformatics approach to decipher the proteome changes related to sustained growth at low temperatures to increase our understanding of cold adaptation mechanisms in a. ferrooxidans strains. changes in protein abundance in response to low temperatures (5 and 15°c) were monitored and ... | 2011 | 21604047 |
| ferric reductase activity of the arsh protein from acidithiobacillus ferrooxidans. | the arsh gene is one of the arsenic resistance system in bacteria and eukaryotes. the arsh protein was annotated as a nadph-dependent flavin mononucleotide (fmn) reductase with unknown biological function. here we report for the first time that the arsh protein showed high ferric reductase activity. glu104 was an essential residue for maintaining the stability of the fmn cofactor. the arsh protein may perform an important role for cytosolic ferric iron assimilation in vivo. | 2011 | 21617342 |
| the community dynamics of major bioleaching microorganisms during chalcopyrite leaching under the effect of organics. | to determine the effect of organics (yeast extract) on microbial community during chalcopyrite bioleaching at different temperature, real-time polymerase chain reaction (pcr) was employed to analyze community dynamics of major bacteria applied in bioleaching. the results showed that yeast extract exerted great impact on microbial community, and therefore influencing bioleaching rate. to be specific, yeast extract was adverse to this bioleaching process at 30°c due to decreased proportion of impo ... | 2011 | 21638040 |
| a genomic island provides acidithiobacillus ferrooxidans atcc 53993 additional copper resistance: a possible competitive advantage. | there is great interest in understanding how extremophilic biomining bacteria adapt to exceptionally high copper concentrations in their environment. acidithiobacillus ferrooxidans atcc 53993 genome possesses the same copper resistance determinants as strain atcc 23270. however, the former strain contains in its genome a 160-kb genomic island (gi), which is absent in atcc 23270. this gi contains, amongst other genes, several genes coding for an additional putative copper atpase and a cus system. ... | 2011 | 21789491 |
| an investigation of biooxidation ability of acidithiobacillus ferrooxidans using nmr relaxation measurement. | nmr relaxation measurements can provide a simple means for understanding biological activity of cells in solution with known composition. it has the advantage that it is an in situ, non-intrusive technique, and the acquisition is fast. the iron oxidation ability of acidithiobacillus ferrooxidans was investigated using nmr relaxation measurements. the transversal relaxation is characterized by a time constant, t(2), which is sensitive to the chemical environment. fe(3+) ion has more significant t ... | 2011 | 21784630 |
| evolution of biofilms during the colonization process of pyrite by acidithiobacillus thiooxidans. | we have applied epifluorescence principles, atomic force microscopy, and raman studies to the analysis of the colonization process of pyrite (fes(2)) by sulfuroxidizing bacteria acidithiobacillus thiooxidans after 1, 15, 24, and 72 h. for the stages examined, we present results comprising the evolution of biofilms, speciation of s (n) (2-) /s(0) species, adhesion forces of attached cells, production and secretion of extracellular polymeric substances (eps), and its biochemical composition. after ... | 2011 | 21773763 |
| an extracellular tetrathionate hydrolase from the thermoacidophilic archaeon acidianus ambivalens with an activity optimum at ph 1. | background: the thermoacidophilic and chemolithotrophic archaeon acidianus ambivalens is routinely grown with sulfur and co(2)-enriched air. we had described a membrane-bound, tetrathionate (tt) forming thiosulfate:quinone oxidoreductase. here we describe the first tt hydrolase (tth) from archaea. results: a. ambivalens cells grown aerobically with tt as sole sulfur source showed doubling times of 9?h and final cell densities of up to 8?×?10(8)/ml. tth activity (˜0.28?u/mg protein) was found in ... | 2011 | 21747790 |
| the co-culture of acidithiobacillus ferrooxidans and acidiphilium acidophilum enhances the growth, iron oxidation, and co(2) fixation. | although the synergetic interactions between chemolithoautotroph acidithiobacillus ferrooxidans and heterotroph acidiphilium acidophilum have drawn a share of attention, the influence of aph. acidophilum on growth and metabolic functions of at. ferrooxidans is still unknown on transcriptional level. to assess this influence, a co-culture composed by at. ferrooxidans and aph. acidophilum was successfully acclimated in this study. depending on the growth dynamics, at. ferrooxidans in co-culture ha ... | 2011 | 21691775 |
| draft genome of the psychrotolerant acidophile acidithiobacillus ferrivorans ss3. | acidithiobacillus ferrivorans ss3 is a psychrotolerant acidophile capable of growth in the range of 5-¦ to 30-¦c (optimum, ôëê25-¦c). it gains energy from the oxidation of ferrous iron and inorganic sulfur compounds and obtains organic carbon from carbon dioxide. here, we present the draft genome sequence of a. ferrivorans ss3 that will permit investigation of genes involved in growth in acidic environments at low temperatures. | 2011 | 21705598 |
| growth of acidithiobacillus ferrooxidans atcc 23270 in thiosulfate under oxygen-limiting conditions generates extracellular sulfur globules by means of a secreted tetrathionate hydrolase. | production of sulfur globules during sulfide or thiosulfate oxidation is a characteristic feature of some sulfur bacteria. although their generation has been reported in acidithiobacillus ferrooxidans, its mechanism of formation and deposition, as well as the physiological significance of these globules during sulfur compounds oxidation, are currently unknown. under oxygen-sufficient conditions (osc), a. ferrooxidans oxidizes thiosulfate to tetrathionate, which accumulates in the culture medium. ... | 2011 | 21833324 |
| microbial diversity in anaerobic sediments at rio tinto, a naturally acidic environment with a high heavy metal content. | the tinto river is an extreme environment located at the core of the iberian pyritic belt (ipb). it is an unusual ecosystem due to its size (100 km long), constant acidic ph (mean ph, 2.3), and high concentration of heavy metals, iron, and sulfate in its waters, characteristics that make the tinto river basin comparable to acidic mine drainage (amd) systems. in this paper we present an extensive survey of the tinto river sediment microbiota using two culture-independent approaches: denaturing gr ... | 2011 | 21724883 |
| telling the whole story in a 10,000-genome world. | abstract: | 2011 | 21714939 |
| analysis of the surface proteins of acidithiobacillus ferrooxidans strain sp5/1 and the new, pyrite-oxidizing acidithiobacillus isolate hv2/2, and their possible involvement in pyrite oxidation. | two strains of rod-shaped, pyrite-oxidizing acidithiobacilli, their cell envelope structure and their interaction with pyrite were investigated in this study. cells of both strains, acidithiobacillus ferrooxidans strain sp5/1 and the moderately thermophilic acidithiobacillus sp. strain hv2/2, were similar in size, with slight variations in length and diameter. two kinds of cell appendages were observed: flagella and pili. besides a typical gram-negative cell architecture with inner and outer mem ... | 2011 | 21698546 |
| the effect of the introduction of exogenous strain acidithiobacillus thiooxidans a01 on functional gene expression, structure and function of indigenous consortium during pyrite bioleaching. | acidithiobacillus thiooxidans a01 was added to a consortium of bioleaching bacteria including acidithiobacilluscaldus, leptospirillumferriphilum, acidithiobacillus ferrooxidans, sulfobacillus thermosulfidooxidans, acidiphilium spp., and ferroplasma thermophilum cultured in modified 9k medium containing 0.5% (w/v) pyrite, and 10.7% increase of bioleaching rate was observed. changes in community structure and gene expression were monitored with real-time pcr and functional gene arrays (fgas). real ... | 2011 | 21705214 |
| spatial and temporal analysis of the microbial community in the tailings of a pb-zn mine generating acidic drainage. | analysis of spatial and temporal variations in the microbial community in the abandoned tailings impoundment of a pb-zn mine revealed distinct microbial populations associated with the different oxidation stages of the tailings. although acidithiobacillus ferrooxidans and leptospirillum spp. were consistently present in the acidic tailings, acidophilic archaea, mostly ferroplasma acidiphilum, were predominant in the oxidized zones and the oxidation front, indicating their importance to generatio ... | 2011 | 21705549 |
| development of bacterial community during spontaneous succession on spoil heaps after brown coal mining. | changes in the abundance of bacteria and fungi and in the composition of bacterial communities during primary succession were investigated in a brown coal mine deposit area near sokolov, the czech republic, using phospholipid fatty acids analysis, microarray and 16s rrna gene sequencing. the study considered a chronosequence of sites undergoing spontaneous succession: 6-, 12-, 21- and 45-year-old and a 21-year-old site revegetated with alnus glutinosa. during succession, organic carbon and the t ... | 2011 | 21707674 |
| Sulfur metabolism in the extreme acidophile acidithiobacillus caldus. | Given the challenges to life at low pH, an analysis of inorganic sulfur compound (ISC) oxidation was initiated in the chemolithoautotrophic extremophile Acidithiobacillus caldus. A. caldus is able to metabolize elemental sulfur and a broad range of ISCs. It has been implicated in the production of environmentally damaging acidic solutions as well as participating in industrial bioleaching operations where it forms part of microbial consortia used for the recovery of metal ions. Based upon the re ... | 2011 | 21687411 |
| Community genomic analysis of an extremely acidophilic sulfur-oxidizing biofilm. | Highly acidic (pH 0-1) biofilms, known as 'snottites', form on the walls and ceilings of hydrogen sulfide-rich caves. We investigated the population structure, physiology and biogeochemistry of these biofilms using metagenomics, rRNA methods and lipid geochemistry. Snottites from the Frasassi cave system (Italy) are dominated (>70% of cells) by Acidithiobacillus thiooxidans, with smaller populations including an archaeon in the uncultivated 'G-plasma' clade of Thermoplasmatales (>15%) and a bact ... | 2011 | 21716305 |
| unraveling the acidithiobacillus caldus complete genome and its central metabolisms for carbon assimilation. | acidithiobacillus caldus is one of the dominant sulfur-oxidizing bacteria in bioleaching reactors. it plays the essential role in maintaining the high acidity and oxidation of reduced inorganic sulfur compounds during bioleaching process. in this report, the complete genome sequence of a. caldus sm-1 is presented. the genome is composed of one chromosome (2,932,225 bp) and four plasmids (platc1, platc2, platc3, platcm) and it is rich in repetitive sequences (accounting for 11% of the total genom ... | 2011 | 21703548 |
| Genome wide identification of Acidithiobacillus ferrooxidans (ATCC 23270) transcription factors and comparative analysis of ArsR and MerR metal regulators. | Acidithiobacillus ferrooxidans is a chemolithoautotrophic acidophilic bacterium that obtains its energy from the oxidation of ferrous iron, elemental sulfur, or reduced sulfur minerals. This capability makes it of great industrial importance due to its applications in biomining. During the industrial processes, A. ferrooxidans survives to stressing circumstances in its environment, such as an extremely acidic pH and high concentration of transition metals. In order to gain insight into the organ ... | 2011 | 21830017 |
| [compositions of microbial communities in sulfide nickel ore waste piles ]. | | 2011 | 22073558 |
| The extremophile Acidithiobacillus ferrooxidans possesses a c-di-GMP signalling pathway that could play a significant role during bioleaching of minerals. | Aims: The primary goal of this study was to characterize the existence of a functional c-di-GMP pathway in the bioleaching bacterium Acidithiobacillus ferrooxidans. Methods and Results: A bioinformatic search revealed that the genome sequence of At. ferrooxidans ATCC 23270 codes for several proteins involved in the c-di-GMP pathway, including diguanylate cyclases (DGC), phosphodiesterases and PilZ effector proteins. Overexpression in Escherichia coli demonstrated that four At. ferrooxidans gen ... | 2011 | 22098310 |
| adaptation of acidithiobacillus bacteria to metallurgical wastes and its potential environmental risks. | metallurgical wastes - oxygen converter sludge, dust from cast iron production, lead matte, and slag from recycling of used lead batteries - were treated with acidithiobacillus bacteria. bacterial activity and adaptability on waste and some waste mixtures were investigated. acidithiobacillus bacteria may easily attack oxygen converter sludge, lead matte and slag and affect the mobility of metals. cast iron dust is not a suitable substrate for applied bacteria due to the absence of reduced sulfur ... | 2011 | 21946045 |
| bioleaching in brackish waters-effect of chloride ions on the acidophile population and proteomes of model species. | high concentrations of chloride ions inhibit the growth of acidophilic microorganisms used in biomining, a problem particularly relevant to western australian and chilean biomining operations. despite this, little is known about the mechanisms acidophiles adopt in order to tolerate high chloride ion concentrations. this study aimed to investigate the impact of increasing concentrations of chloride ions on the population dynamics of a mixed culture during pyrite bioleaching and apply proteomics t ... | 2011 | 22124722 |
| insights into the ph up-shift responsive mechanism of acidithiobacillus ferrooxidans by microarray transcriptome profiling. | to define the molecular response of acidithiobacillus ferrooxidans under ph up-shift, temporal gene expression profiles were examined by using whole-genome dna microarrays for a. ferrooxidans. approximately 30% of the 3,132 genes represented on the microarray were significantly upregulated over a 160-min period, while about 14% were significantly downregulated. our results revealed that a. ferrooxidans showed potential self-protection and self-regulation performance in response to ph up-shift st ... | 2011 | 21904969 |
| organic matter in sediments of an acidic mining lake as assessed by lipid analysis. part i: fatty acids. | fatty acid (fa) patterns of sediments collected from the bottom of an acidic mine pit lake (aml) at different depths (surface sediment: 0 to 1cm; deep sediment: 4 to 5cm) were studied to characterize microbial communities and the sources of sedimentary organic matter (som). studies were performed on the molecular level utilizing source-specific, diagnostic fa biomarkers. the biomarker-based approach has been used widely in marine sediment studies, but has not been applied for sediments from amls ... | 2011 | 22119026 |
| kinetics of anaerobic elemental sulfur oxidation by ferric iron in acidithiobacillus ferrooxidans and protein identification by comparative 2-de-ms/ms. | elemental sulfur oxidation by ferric iron in acidithiobacillus ferrooxidans was investigated. the apparent michaelis constant for ferric iron was 18.6 mm. an absence of anaerobic ferric iron reduction ability was observed in bacteria maintained on elemental sulfur for an extended period of time. upon transition from ferrous iron to elemental sulfur medium, the cells exhibited similar kinetic characteristics of ferric iron reduction under anaerobic conditions to those of cells that were originall ... | 2011 | 22057833 |
| electricity generation by microorganisms in the sediment-water interface of an extreme acidic microcosm. | the attachment of microorganisms to electrodes is of great interest for electricity generation in microbial fuel cells (mfc) or other applications in bioelectrochemical systems (bes). in this work, a microcosm of the acidic ecosystem of río tinto was built and graphite electrodes were introduced at different points. this allowed the study of electricity generation in the sediment/water interface and the involvement of acidophilic microorganisms as biocatalysts of the anodic and cathodic reaction ... | 2011 | 22069151 |
| the small heat shock proteins from acidithiobacillus ferrooxidans: gene expression, phylogenetic analysis, and structural modeling. | abstract: | 2011 | 22151959 |
| gene expression modulation by heat stress in acidithiobacillus ferrooxidans lr. | during bioleaching, acidithiobacillus ferrooxidans is subjected to different types of stress, including heat stress, which affect bacterial growth. in this work, real time quantitative pcr was used to analyze the expression of heat shock genes, as well as genes that encode proteins related to several functional categories in a. ferrooxidans. cells were submitted to long-term growth and heat shock, both at 40°c. the results showed that heat shock affected the expression levels of most genes inves ... | 2011 | 22086463 |
| analysis of early bacterial communities on volcanic deposits on the island of miyake (miyake-jima), japan: a 6-year study at a fixed site. | microbial colonization on new terrestrial substrates represents the initiation of new soil ecosystem formation. in this study, we analyzed early bacterial communities growing on volcanic ash deposits derived from the 2000 mount oyama eruption on the island of miyake (miyake-jima), japan. a site was established in an unvegetated area near the summit and investigated over a 6-year period from 2003 to 2009. collected samples were acidic (ph 3.0-3.6), did not utilize any organic substrates in eco mi ... | 2011 | 22075623 |
| development of a markerless gene replacement system in acidithiobacillus ferrooxidans and construction of a pfkb mutant. | the extremely acidophilic, chemolithoautotrophic acidithiobacillus ferrooxidans is an important bioleaching bacterium of great value in the metallurgical industry and environmental protection. in this report, a mutagenesis system based on the homing endonuclease i-scei was developed to produce targeted, unmarked gene deletions in the strain a. ferrooxidans atcc 23270. a targeted phosphofructokinase gene (pfkb) mutant of a. ferrooxidans atcc 23270 was constructed by homologous recombination and i ... | 2011 | 22210219 |
| synthesis and evaluation of tetrahedral intermediate mimic inhibitors of 3-deoxy-d-manno-octulosonate 8-phosphate synthase. | 3-deoxy-d-manno-octulosonate 8-phosphate (kdo8p) synthase catalyses the first committed step in the biosynthesis of 3-deoxy-d-manno-octulosonate (kdo), an important component of the lipopolysaccharide of gram-negative bacteria. the pathway for kdo biosynthesis has been identified as a potential target of antibacterial drug design. the reaction catalysed by kdo8p synthase is an aldol-like condensation between phosphoenolpyruvate (pep) and d-arabinose 5-phosphate (a5p) and proceeds through a bisph ... | 2011 | 22204912 |
| arsenopyrite and pyrite bioleaching: evidence from xps, xrd and icp techniques. | in this work, a multi-technical bulk and surface analytical approach was used to investigate the bioleaching of a pyrite and arsenopyrite flotation concentrate with a mixed microflora mainly consisting of acidithiobacillus ferrooxidans. x-ray diffraction, x-ray photoelectron spectroscopy (xps) and x-ray-induced auger electron spectroscopy mineral surfaces investigations, along with inductively coupled plasma-atomic emission spectroscopy and carbon, hydrogen, nitrogen and sulphur determination (c ... | 2011 | 21847529 |
| changes in the composition of an acid mine drainage microbial community upon successive transfers in medium containing low-grade copper sulfide. | a consortium of microorganisms from acid mine drainage samples was cultured in modified 9 k medium containing low-grade copper sulfide. the culture was maintained for sixty days and then transferred to fresh medium. this process was repeated three more times and a final consortium exhibiting a copper extraction rate of 89.3% was obtained. rflp and microarrays analysis of 16s rrna sequences retrieved from the consortia showed that acidithiobacilluscaldus, leptospirillumferriphilum, sulfobacillus ... | 2011 | 21862325 |
| draft genome sequence of the extremely acidophilic biomining bacterium acidithiobacillus thiooxidans atcc 19377 provides insights into the evolution of the acidithiobacillus genus. | acidithiobacillus thiooxidans is a mesophilic, extremely acidophilic, chemolithoautotrophic gammaproteobacterium that derives energy from the oxidation of sulfur and inorganic sulfur compounds. here we present the draft genome sequence of a. thiooxidans atcc 19377, which has allowed the identification of genes for survival and colonization of extremely acidic environments. | 2011 | 22123759 |
| a copper-catalyzed bioleaching process for enhancement of cobalt dissolution from spent lithium-ion batteries. | a copper-catalyzed bioleaching process was developed to recycle cobalt from spent lithium-ion batteries (mainly licoo(2)) in this paper. the influence of copper ions on bioleaching of licoo(2) by acidithiobacillus ferrooxidans (a.f) was investigated. it was shown that almost all cobalt (99.9%) went into solution after being bioleached for 6 days in the presence of 0.75g/l copper ions, while only 43.1% of cobalt dissolution was obtained after 10 days without copper ions. edx, xrd and sem analyses ... | 2012 | 22100221 |
| Genomic insights into microbial iron oxidation and iron uptake strategies in extremely acidic environments. | This minireview presents recent advances in our understanding of iron oxidation and homeostasis in acidophilic Bacteria and Archaea. These processes influence the flux of metals and nutrients in pristine and man-made acidic environments such as acid mine drainage and industrial bioleaching operations. Acidophiles are also being studied to understand life in extreme conditions and their role in the generation of biomarkers used in the search for evidence of existing or past extra-terrestrial life ... | 2011 | 22050575 |
| Performances of two biotrickling filters in treating H(2)S-containing waste gases and analysis of corresponding bacterial communities by pyrosequencing. | Two identical biotrickling filters named BTFa and BTFb were run in parallel to examine their performances in removing hydrogen sulfide. BTFa was filled with ceramic granules, and BTFb was filled with volcanic rocks. The results showed that BTFb was more robust than BTFa under acidic conditions. At empty bed residence times (EBRTs) of 20 and 15 s, the removal efficiency of BTFa was close to 100%. At EBRTs of 10 and 5 s, the removal efficiency of BTFa slightly decreased. The removal efficiencies o ... | 2011 | 22207217 |
| Influence of the sulfur species reactivity on biofilm conformation during pyrite colonization by Acidithiobacillus thiooxidans. | Massive pyrite (FeS(2)) electrodes were potentiostatically modified by means of variable oxidation pulse to induce formation of diverse surface sulfur species (S( n ) (2-), S(0)). The evolution of reactivity of the resulting surfaces considers transition from passive (e.g., Fe(1-x )S(2)) to active sulfur species (e.g., Fe(1-x )S(2-y ), S(0)). Selected modifie ... | 2011 | 22113561 |
| Supplementation of inorganic phosphate enhancing the removal efficiency of tannery sludge-borne Cr through bioleaching. | Four inorganic mineral nutrients including NH4+, K+, Mg2+ and soluble inorganic phosphate (Pi) were investigated to reveal the potential limiting nutrients for tannery sludge bioleaching process driven by Acidithiobacillus species, and the feasibility of supplementing the limiting nutrients to accelerate tannery sludge bioleaching was studied in the present study. It was found that the concentration of Pi was lower than 3.5 mg/L throughout the whole bioleaching process, which is the most probabl ... | 2011 | 21864881 |
| An extended ß7a7 substrate-binding loop is essential for efficient catalysis by 3-deoxy-D-manno-octulosonate 8-phosphate synthase. | The enzyme 3-deoxy-D-manno-octulosonate 8-phosphate (KDO8P) synthase catalyzes the reaction between phosphoenolpyruvate and arabinose 5-phosphate (A5P) in the first committed step in the biosynthetic pathway for the formation of 3-deoxy-D-manno-octulosonate, an important component in the cell wall of Gram-negative bacteria. KDO8P synthase is evolutionarily related to the first enzyme of the shikimate pathway, 3-deoxy-D-arabino-heptulosonate 7-phosphate (DAH7P) synthase, which uses erythrose 4-ph ... | 2011 | 21942786 |
| [leaching of copper ore of the udokanskoe deposit at low temperatures by an association of acidophilic chemolithotrophic microorganisms]. | pure cultures of indigenous microorganisms acidithiobacillus ferrooxidans strain tfud, leptospirillum ferrooxidans strain lud, and sulfobacillus thermotolerans strain sud have been isolated from the oxidation zone of sulfide copper ore of the udokanskoe deposit. regimes of bacterial-chemical leaching of ore have been studied over a temperature range from -10 to +20 degrees c. effects of ph, temperature, and the presence of microorganisms on the extraction of copper have been shown. bacterial lea ... | 2011 | 22232899 |
| customized design of electronic noses placed on top of air-lift bioreactors for in situ monitoring the off-gas patterns. | a specially designed electronic nose was coupled to an air-lift bioreactor in order to perform on-line monitoring of released vapors. the sensor array was placed at the top of the bioreactor sensing the headspace in equilibrium with the evolving liquor at any time without the need of aspiration and pumping of gases into a separated sensor chamber. the device was applied to follow the off-gas of a bioreactor with acidithiobacillus thiooxidans grown on beds of elemental sulfur under aerobic condit ... | 2012 | 22212349 |