bluuebunny/crossref_metadata_2025 huggingface dataset:
Microbial Dissolution of Iron Surface Coatings in Industrial Minerals
Authors: Šuba Jaroslav , Štyriaková Iveta , Štyriak Igor , Štyriaková Darina
Published: August 2017

The purpose of this work was to investigate the phenomenon of microbial iron reduction in industrial minerals and materials. These materials are generally not pure, often associated with impurities usually in the form of Fe3+. In all cases, the presence of iron affects the colour and the physical properties of the mineral and therefore lowers their industrial value and limits their application. In this study bentonite, kaolin and quartz sand sample were used for the experiments and compared in effectiveness of iron dissolution. The experimental results showed that after 30 days of bioleaching process, bacteria are able to remove 9.29% of Fe occurring in the kaolin sample (K-I) in amorphous form of oxyhydroxides and approximately 12% of Fe from the bentonite sample (B-JP) also in amorphous form of oxyhydroxides. In the quartz sand sample C3-15D, the concentration of Fe decreased by 15% after 15 days of bioleaching process and in the sample C3-30D after 30 days of bioleaching process by 24.7%.
Changes in Metal Leachability through Stimulation of Iron Reducing Communities within Waste Sludge
Authors: Roberts Mark , Sapsford Devin , Weightman Andrew , Webster Gordon
Published: August 2017

Bioreduction of ferric iron-rich wastes is a rapidly emerging technology for the extraction/ recovery of metals from low-grade ores and metallurgical wastes. However, despite studies being successful, they have only been demonstrated at laboratory scale and issues relating to economic, industrial scale application have yet to be studied. Using bioreduction as a pre-treatment to increase recovery yield is a relatively new concept. This study examines the biostimulation of microbial communities to induce bioreduction of metalliferous sludge and the effect that this has on the leachability of metals from the waste using dilute sulphuric acid. Data shows an increase in both zinc and copper leachability after bioreduction, with maximum six fold and eleven fold increase (compared to pre-treatment) in the amount of zinc and copper leached respectively.
The MONDO Minerals Nickel Sulfide Bioleach Project: From Test Work to Early Plant Operation
Authors: Neale John , Seppälä Janne , Laukka Arto , van Aswegen Pieter , Barnett Stephen , Gericke Mariekie
Published: August 2017

Mondo Minerals owns talc mines in Finland at Sotkamo and Vuonos. A by-product of their talc mining operations is a high-grade sulfide concentrate containing pyrrhotite, pentlandite, pyrite, gersdorffite and magnesite. Nickel is the main metal of economic interest, but the concentrate also contains a small amount of cobalt and a significant quantity of arsenic. Multiple processing options were evaluated before identifying Mintek’s bioleaching technology as the most suitable for the recovery of nickel and cobalt from this stream. This paper describes the technical development of the process, from laboratory test work to plant design and early plant operation.
Investigation of Controlled Redox Potential with Pyrite during Chalcopyrite Bioleaching by Mixed Moderately Thermophiles
Authors: Huang Xiao Tao , Wang Jun , Zhao Hong Bo , Gan Min , Liao Rui , Liyu Jun Wen , Wang Xing Xing , Hong Mao Xin , Qin Wen Qing , Qiu Guan Zhou
Published: August 2017

Various methods of controlling redox potential (ORP) with electrochemical bioreactor and others have been investigated to increase copper extraction of chalcopyrite in bioleaching,but less attention has been paid to reducing ferric to ferrous ions. Therefore, in this work, the redox potential of chalcopyrite bioleaching system in the presence of mixed moderately thermophiles containing Leptospirillum. ferriphilum,Acidithiobacillus. caldus and Sulfobacillus.thermosulfidooxidans has been controlled by pyrite. It was found that at a constant pH of 2.0, the addition of pyrite can reduce ferric to ferrous ion to a large extent, and the lower ORP values can be obtained. Bioleaching experiments indicated that the time for adding pyrite caused different bioleaching behaviors of chalcopyrite. The high copper extraction can be obtained by added pyrite at a low ORP values (<420 mV vs. Ag/AgCl). The XRD tests and SEM images showed that the amounts of formed jarosite increased as the pyrite addition, and the loose and porous jarosite can be found at low ORP values.
Incorporation of Indigenous Microorganisms Increases Leaching Rates of Rare Earth Elements from Western Australian Monazite
Authors: Corbett Melissa K. , Eksteen Jacques J. , Niu Xi Zhi , Watkin Elizabeth L.J.
Published: August 2017

A large number of microbial species commonly called phosphate solubilizing microorganisms (PSMs) are efficient at converting insoluble phosphate to soluble forms to prevent phosphorus limitation. This study examined the impact that PSMs had on a sterile and non-sterile monazite source and determined that they could be applied for bioleaching purposes to recover rare earth elements (REEs). On sterile monazite, Penicillum sp. released a total REE concentration of 12.32 mg L-1 after incubation for 8 days, however, this doubled when inoculated on to non-sterile ore (23.7 mg L-1). Similar results were recorded with Enterobacter aerogenes, Pantoea agglomerans and Pseudomonas putida. Abiotic controls leached a total REE level of 0.65 mg L-1. Examination of the leachate by HPLC identified several low molecular weight organic acids that corresponded with decreases in the media pH. The presence of a native consortia from the monazite ore combined with a known PSMs was more effective at leaching REEs from the monazite matrix than a single isolates or by the native population alone.
Fabrication of Magnetic Polymer Composite Sorbents and its Application for Recovery of Platinum from Acidic Solution
Authors: Song Myung Hee , Reddy D. Harikishore Kumar , Bediako John Kwame , Lin Shuo , Yun Yeoung Sang
Published: August 2017

Magnetic MnFe2O4 nanoparticles (MNPs) were fabricated and entrapped in amine-rich chitosan (CS) sorbents containing multi-walled carbon nanotubes (MWCNTs) or polyethyleneimine (PEI). Magnetic polymer composite sponges (MPCSs) and magnetic polymer composite fibers (MPCFs) were prepared through mixing each of MWCNT and PEI with MNPs-CS solution. The successful fabrication of MPCSs and MPCFs was confirmed through FTIR and VSM analyses. The as-fabricated MPCSs and MPCFs were used for adsorptive recovery of Pt (IV) from acidic solution. The maximum uptakes of Pt (IV) ions by the MPCSs and MPCFs were estimated to be 218.2 ± 8.3 and 371.4 ± 16.8 mg/g, respectively. Moreover, the Pt (IV)-loaded MPCSs and MPCFs were easily separated from aqueous solution under magnetic field after sorption process.
Recent Advances in Biomining and Microbial Characterisation
Authors: Kaksonen Anna H. , Boxall Naomi J. , Bohu Tsing , Usher Kayley , Morris Christina , Wong Pan Yu , Cheng Ka Yu
Published: August 2017

Since the discovery of bioleaching microorganisms and their role in metal extraction in the 1940s, a number of technical approaches have been developed to enhance microbially catalysed solubilisation of metals from ores, concentrates and waste materials. Biomining has enabled the transformation of uneconomic resources to reserves, and thus help to alleviate the challenges related to continually declining ore grades. The rapid advancement of microbial characterisation methods has vastly increased our understanding of microbial communities in biomining processes. The objective of this paper is to review the recent advances in biomining processes and microbial characterisation.
Molecular Regulatory Network Involved in Biofilm Structure Development by Acidithiobacillus thiooxidans Includes Pel Exopolysaccharide Machinery
Authors: Diaz Mauricio , Guiliani Nicolas
Published: August 2017

The Acidithiobacillus genus plays a relevant role in bioleaching. The molecular understanding of biofilm formation has been pointed out to design biological strategies to improve the efficiency of this industrial process and to prevent environmental damages caused by acid mine/rock drainages. In Acidithiobacillus spp., the molecular mechanisms involved in biofilm formation are currently emerging. The second messenger cyclic diguanylate (c-di-GMP) appears as a key player for biofilm formation by Acidithiobacillus sp. Here, results obtained from genomic analysis to characterize c-di-GMP pathway in At. thiooxidans are reported. Intracellular levels of c-di-GMP have been previously measured and data indicated that they are higher in adhered cells than planktonic ones. During the course of characterization of c-di-GMP effectors, a complete pel-like gene cluster has been identified in At. thiooxidans. By using total RNA obtained from planktonic and adhered sulfur-grown cells, transcriptomic analysis revealed that pelA belonging to the pel-like gene cluster is overexpressed in adhered cells. Moreover, genetic experiments were performed to compare wild type and null-mutant strains of At. thiooxidans for assessing the role of Pel exopolysaccharide. All together, the results obtained suggest a specific role for Pel machinery in the attachment to solid energy substrates by At. thiooxidans.
Expression of Candidate Cold Stress and Metabolic Related Genes in Acidithiobacillus ferrivorans PQ33 Strain Using Ferrous Iron as Electron Donor
Authors: Guerra-Bieberach Gregory , Ccorahua-Santo Robert , Eca Anika , Bernaldo Jordan , Sánchez Tito , Rojas-Ayala Chachi , Ramirez Pablo
Published: August 2017

The identification of genes involved in cold adaptations of psychrotolerant bacteria Acidithiobacillus ferrivorans is important for biomining processes that take place at low temperatures like Andean mining installations in Peru. We have performed relative quantification RT-qPCR on candidate genes to have a role in adaptations at low temperature (5°C). The candidate genes analyzed were six: Two trehalose synthesis pathway genes, trehalose synthase (treS) and malto-oligosiltrehalose trehalohydrolase (treZ) showing no overexpression at 5°C. Two diguanylate cyclases genes related to exopolymer synthesis and biofilm formation (designated as dgc-I and dgc-II in this paper) were overexpressed at 21°C. The rusA and rusB genes involved in iron oxidation showed no significant change for rusA and no expression for rusB gene in any of both conditions. Genes rpoC, gyrB and alaS were validated as reference genes. These results show congruency with trancriptomics studies about gene expression of A. ferrivorans. Furthermore, the trehalose synthesis genes show no overexpression at low temperatures suggesting that other cold adaptation mechanisms are involved.
Transcription Dynamics of CBB-Pathway Genes in Acidithiobacillus thiooxidans Growing under Different CO2 Levels
Authors: Marín Sabrina , Acosta Mauricio , Galleguillos Pedro A. , Villegas Yohan , Cautivo Dina , Zepeda Víctor J. , Demergasso Cecilia
Published: August 2017

Acidithiobacillus thiooxidans is one of the most stable components in the consortium of microorganisms inhabiting the copper bioleaching heap of Minera Escondida Limitada. CalvinBenson-Bassham (CBB) is the CO2 fixation pathway most used by aerobic bacteria, and is the exclusive pathway used by A. thiooxidans. In this work, the population dynamics and the transcriptomic dynamics of five key genes involved in the A. thiooxidans CBB pathway were studied in bioleaching column and pure culture tests at different concentrations of CO2 availability. Association between CO2 level, population dynamics and relative expression of CBB-genes was discovered. Differences between CBB pathways from closely related species were reported. The transcription profile modelling could provide useful knowledge for improving industrial bioleaching operations.
Microbial Ferrous Ion Oxidation versus Ferric Ion Precipitation at Low Temperature Conditions
Authors: Chukwuchendo Emmanuel Chinonso , Ojumu Tunde Victor
Published: August 2017

Ferric ion precipitation in a typical bioleach operation is known to be inevitable. However, its management has been emphasized as critical to efficiently maximize the potential that bioleach technique offers, especially in heap bioleach systems. Although there are some studies on ferric ion precipitation, limited studies exist in the context of a cold condition which often prevails in some operations. This study investigated ferrous ion biooxidation and ferric ion precipitation under cold temperature conditions. The results showed that maximum ferrous ion oxidation rates of 1.05, 1.25, 1.51 and 1.60 mmol/L/h at 6, 7, 8 and 10°C respectively were achieved in packed column reactor. The results further showed a simultaneous ferric ion precipitation during the oxidation process. The kinetics of ferric ion precipitation follows a first order kinetics with the rate constants of 0.0066, 0.0074, 0.0080 and 0.011 h-1. Activation energies of 68 and 77 kJ/mol were obtained for both ferrous ion biooxidation and ferric ion precipitation respectively. Although slow kinetics are expected for both processes, the kinetics information may be useful for design management consideration at least to predict when bioleach liquor would likely run out of dissolved ferric ion.
Comparative Study of NaCl-Tolerance Mechanisms in Acidophilic Iron-Oxidizing Bacteria and Archaea
Authors: Rivera-Araya Javier , Schlömann Michael , Levicán Gloria J.
Published: August 2017

Chloride leaching is considered a promising alternative method to recover copper from chalcopyrite and other primary copper sulfides, because it favors the leaching kinetics and avoids passivation of minerals. Nevertheless, chloride ions are highly toxic for iron-oxidizing microorganisms that participate in the bioleaching process. A comparative genomic analysis was carried out based on the complete genomes of bacteria belonging to Nitrospirae, Firmicutes, Actinobacteria and Proteobacteria phyla, and of archaea belonging to Euryarchaeota and Crenarchaeota was carried out to identify molecular determinants involved in chloride tolerance of acidophilic iron-oxidizing microorganisms. The results obtained showed that representative Nitrospirae and Firmicutes harbor genes for the biosynthesis and uptake of compatible solutes such as ectoine, trehalose and potassium, which have been shown to have a role in salt tolerance. Microorganisms belonging to other phyla harbor genes for potassium transporters, but no genes for compatible solutes were detected. In agreement with the bioinformatic results, minimum inhibitory concentration (MIC) determinations and growth kinetics experiments showed that Leptospirillum ferriphilum (Nitrospirae) was more tolerant to NaCl than Acidithiobacillus ferrooxidans (Proteobacteria). Furthermore, it was observed that the addition of 0.5 mM ectoine to the L. ferriphilum culture stimulated growth in the presence of 100 mM NaCl. On the contrary, ectoine had no effect on the growth of At. ferrooxidans. These results suggest that ectoine and likely trehalose could play a key role in chloride tolerance in L. ferriphilum. conferring adaptative advantages compared to A. ferrooxidans and possibly other iron-oxidizing microorganisms.
Production of Amphiphilic Hydroxamate Siderophores Marinobactins by Marinobacter sp. DS40M6 for Bioflotation Process
Authors: Schrader Sylvi , Kutschke Sabine , Rudolph Martin , Pollmann Katrin
Published: August 2017

Marinobacter sp. DS40M6 produces the siderophores marinobactins, which are amphiphilic and contain hydroxamate functional groups responsible for a strong complexation of iron(III). First tests about growth and production conditions showed on the one hand a high rate for both growth of bacteria and siderophore production at 25°C. The pH value, on the other hand, demonstrated a contrary effect, thus the optimal pH 7.0 for growth was not the most efficient pH value for siderophore production.
In Situ Characterization of Superficial Organic Composition Changes of Thermoacidophilic Archaea Acidianus manzaensis YN-25 in Response to Energy Substrate
Authors: Liu Li Zhu , Pan Xuan , Xia Xu , Zhou Yu Hang , Nie Zhen Yuan , Xia Jin Lan
Published: August 2017

The differences of superficial (about 10 nm) extracellular polymeric substances (EPS) composition of thermoacidophilic archaea Acidianus manzaensis YN-25 acclimated with different energy substrates (FeS2, CuFeS2, S0, FeSO4) were analyzed in situ for the first time by synchrotron radiation (SR) based carbon K-edge X-ray absorption near edge structure (XANES) spectroscopy. The results showed that there are clear associations between the energy substrates and the changes in organic composition in terms of typical function groups (-C=O, -C-O and -C-N). The archaea acclimated with chalcopyrite and pyrite contain higher proportion of proteins but less polysaccharides compared to cells acclimated with S0.The archaea acclimated with FeSO4 contains the highest proportion of protein which is positively associated with the iron oxidation process, while archaea acclimated with S0 contains more lipids and polysaccharides, which may be favorable to the hydrophobic S0 adsorption and utilization processes.
Type IV Secretion Systems Diversity in the Acidithiobacillus Genus
Authors: Flores-Ríos Rodrigo , Moya-Beltrán Ana , Covarrubias Paulo C. , Acuña Lillian G. , Orellana Omar , Quatrini Raquel
Published: August 2017

Dispersal between genomes of certain mobile genetic elements and their gene cargo depends on conjugative type IV secretion systems. In this work, variants of these nanomachines, tra and trb, have been profiled in publicly available genomes of the genus Acidithiobacillus and in a set of relevant strains. Our analyses show that the trb system is of broad distribution, being present in most of the strains analyzed. In turn, the tra type is present in fewer strains of A. ferrooxidans, A. ferrivorans, A. ferriphilus and A. thiooxidans, and generally correlates with the presence of larger ICE in the respective genomes. Herein, sequence conservation, genomic context, integration site and synteny analyses are performed to infer functionality of the T4SS systems of the acidithiobacilli.
Metagenome-Derived Draft Genome Sequence of Acidithiobacillus ferrooxidans RV1 from an Abandoned Gold Tailing in Neuquén, Argentina
Authors: Ulloa Ricardo , Moya-Beltrán Ana , Issotta Francisco , Nuñez Harold , Covarrubias Paulo C. , Donati Edgardo R. , Quatrini Raquel , Giaveno Alejandra
Published: August 2017

In this work we report the metagenome-derived draft genomic sequence of an enrichment culture dominated by A. ferrooxidans obtained from an airlift bioreactor inoculated with the microbial consortium recovered from the “Relave Viejo” tailing. The genome of this culture was assembled de-novo and by reference, generating a consensus assembly of 3.0 Mb. On the basis of 16S rRNA (100 % identity), average nucleotide identity analysis (99.33% identity) and in silico DNA-DNA hybridization against A. ferrooxidans ATCC 23270T (97.9%), the recovered genome is confirmed to pertain to A. ferrooxidans species. Comparative genomics results are presented to uncover the genetic traits of the variant surviving lime treatment and to further explore the genomic diversity of these model iron oxidizing species.
Simplified Expression and Production of Small Metal Binding Peptides
Authors: Braun Robert , Matys Sabine , Schönberger Nora , Lederer Franziska L. , Pollmann Katrin
Published: August 2017

Phage display for discovery of specific binding peptides is nowadays widely used in the pharmaceutical industry and in many biotechnological applications. Using state-of-the-art cloning techniques we developed an easy-to-use cloning and expression system, allowing the fast production of identified peptides while avoiding proteolysis.
Monitoring of Biofilm Development on Surfaces Using an Electrochemical Method
Authors: Fysun Olga , Maher Alen , Brehm Holger , Wilke Bernd , Langowski Horst Christian
Published: August 2017

Bioleaching is the extraction of metals from ore by microorganisms. Initial attachment and formation of biofilm by microorganisms are very important for the bioleaching due to the mineral oxidation processes. However, very few techniques were proposed to monitor initial stage of biofilms in real time. Therefore, the aim of this work was to probe an electrochemical method on the bacterial biofilm model under the laboratory conditions. It was found that electrochemical method can be suggested for the real time detection of initial phase of P. polymyxa biofilm formation by observation of the potential increase. However, detection of biofilm development at late stages was not successful due to the decrease of the electrochemical potential by full coverage of the test surface. Nevertheless, this technique is supposed as a promising method for early stage detection of desirable biofilms of acidophilic iron oxidizing microorganisms in bioleaching.
Are there Viruses in Industrial Bioleaching Econiches?
Authors: Covarrubias Paulo C. , Muñoz Rodrigo , Bobadilla-Fazzini Roberto A. , Martinez Patricio , Quatrini Raquel
Published: August 2017

Detailed descriptions of the consortia present in commercial mineral processing operations have emerged in recent years, improving our understanding of the biology and the ecology of bioleaching. In spite of this progress, one of the aspects of biomining microbial ecology that remains un-tackled is that of virus-host interactions. The effects of viruses on the dynamics of the bioleaching microbial consortia and their impact in metal recovery is presently unknown. To begin addressing this issue we asked a basic question: ¿Are there viruses in industrial bioleaching econiches? In this work, we answer that question experimentally, assessing the number and types of viral particles recovered in the leachates from different industrial settings, using epifluorescence and transmission electron microscopy. Findings emerging from this work point to an almost null presence of viral particles in the leachates from mineral processing operations, possibly due to structural stability issues of the particles in the extreme acidic and highly oxidant conditions favoured by their potential microbial hosts. In turn, DNA-loaded viral-size vesicles of presently unknown function are frequent and abundant in all samples analysed.
Development of Metal Ion Binding Peptides Using Phage Surface Display Technology
Authors: Schönberger Nora , Matys Sabine , Flemming Katrin , Lehmann Falk , Lederer Franziska L. , Pollmann Katrin
Published: August 2017

Phage surface display technology is a useful tool for the identification of biosorptive peptides. In this work it is used for the identification of cobalt, nickel and gallium binding peptides. We present methods for the enrichment of metal ion binding bacteriophage clones from a commercial phage display library. Metal ion selective peptides are suitable to separate as well as concentrate cobalt and nickel from copper black shale leaching products (EcoMetals project) and gallium from industrial waste waters (EcoGaIn project). In contrast to common capture methods of specific binding phage for solid materials the ionic species have to be immobilized prior to the bio-panning procedure. This was realized by chemical complexation of the metal ions using commercial complexing agents on porous matrices. Moreover, an option to harvest non elutable strong binding phage is proposed.
Biosorption of Heavy Metals Using Organic Waste from Tequila Processing
Authors: Rivera Santillan R.E. , Patricio Ramirez F. , Ayala Pichardo Y. , Ordaz Romero E. , Sanchez Jimenez V.
Published: August 2017

In Mexico and in the world, the metallurgical, petroleum and chemical industries, among others, generate large amounts of pollutants, which when deposited in dams or discharged into rivers, ponds or directly into aquifers generate serious problems for the environment. Biosorption is the phenomenon of passive uptake of metal ions with non-living organic materials, known as biomass, which are generally industrial waste. Active uptake with live biomass is called bioaccumulation. Biosorption is based on the property of some types of inactive or dead biomass to uptake and accumulate these elements by different mechanisms. There are several mechanisms that explain the fixation and retention of metals by the biosorbent used: physical adsorption, ion exchange, complexation, chelation etc. In this work the behavior of three organic residues from the tequila production process at Tarimoro plant, the fiber or bagasse obtained from the must from tequila processing, agave leaves and solid tequila vinasse were evaluated. The tests were carried out by contacting the biomass with a solution containing metal cations such as Cu, Fe and Mn. The maximum adsorption capacity was obtained at a pH of 8 (98% copper adsorption) with agave fiber biomass at temperature of 25°C. The samples studied at temperatures of 25°C showed the lowest concentration values ​​of Cu2+ in residual solution. The adsorption process was found dependent on pH and time. The results obtained allow to affirm that organic wastes from the elaboration of tequila are a viable alternative as biomass in the bioremediation process of toxic heavy metals by a biosorption technique.
South African Coal Tailings Bioflotation for Desulphurization Using Mycobacterium phlei
Authors: Fagan-Endres Marijke A. , Harrison Susan T.L.
Published: August 2017

The large cost of the flotation reagents used in the first-of a two-stage desulphurization flotation process, developed for the treatment of South African waste coal ultrafine tailings, has motivated the investigation of Mycobacterium phlei as an alternative coal bioflotation reagent. Attachment experiments were used to confirm that the microbe attaches to South African coal selectively over pyrite or gangue material present in the coal. Subsequent small scale batch floats using M. phlei successfully showed that the bioflotation process can upgrade and desulphurize the coal tailings feed, and delivered approximately the same concentrate yields as the optimised chemical flotation conditions (37 – 39%). However, a projected financial feasibility analysis that assessed the incorporation of the M. phlei into the two-stage flotation process found that the bioflotation process was not profitable due to the very large flow rate of cells required (2×1016 cells/ton coal) and the associated additional equipment and growth media component costs.
Comparative Analysis of the Sulfate-Reducing Performance and Microbial Colonisation of Three Continuous Reactor Configurations with Varying Degrees of Biomass Retention
Authors: Hessler Tomas , Marais Tynan , Huddy Robert J. , van Hille Robert , Harrison Susan T.L.
Published: August 2017

Biological sulfate reduction represents an alternative and sustainable option to reduce the high sulfate load, precipitate heavy metals and neutralise the acidity associated with acid rock drainage (ARD). Sulfate-reducing enrichment cultures have been developed on simple and complex electron donors from several environmental samples and used to inoculate three reactor configurations, namely a continuous stirred tank bioreactor, up-flow anaerobic packed bed reactor and a linear flow channel reactor, with varying degrees of biomass retention provided by carbon microfibres and polyurethane foam. These matrices are included to enhance microbial attachment and colonisation, allowing for the decoupling of hydraulic retention time and biomass retention time. The bioreactor systems are operated under increasingly stringent conditions through the reduction in the hydraulic residence time. The biological sulfate reduction performance and the biomass concentration of planktonic, matrix-attached and matrix-associated communities are routinely monitored. This investigation makes use of biomass quantification of the planktonic community and, following detachment, the matrix-associated community to investigate the resultant microbial communities in these reactor systems. Evaluation of these mixed microbial communities, and their link to process performance, provides an opportunity to impact the design and operation of pilot- and industrial-scale bioprocesses.
Removal of Arsenic from Aqueous Solution by Aeromonas hydrophila
Authors: Castro Laura , Blázquez M. Luisa , González Felisa , Muñoz Jesús Angel , Ballester Antonio
Published: August 2017

Arsenic contamination is considered as a global environmental problem. This metalloid is known to be carcinogenic in some forms, and is mostly found in the environment as arsenate As (V) and arsenite As (III). Several chemical methods have been established for decontamination of arsenic from ground water including biological treatments. In the present work, the effect of the anaerobic bioreduction of soluble Fe (III) by the strain Aeromonashydrophila on arsenic immobilization has been investigated. The tolerance of this strain to arsenic concentration and the effect of the iron concentration in arsenic immobilization have been studied. The release of ferrous ion indicated the bioreduction of iron and promoted the subsequent arsenic co-precipitation, leading to the formation of various iron-bearing minerals. This precipitate has been observed and identified by Scanning Electron Microscopy and X-ray diffraction analysis as Fe3(AsO4)2(H2O)8.
Immobilization of Arsenic by a Thermoacidophilic Mixed Culture with Pyrite as Energy Source
Authors: Vega Silvia , Weijma Jan , Buisman Cees N.J.
Published: August 2017

Arsenic is an abundant element associated with a wide range of minerals and a major contaminant in metallurgical wastewater. For the immobilization of arsenic, iron arsenate in the very stable mineral scorodite (FeAsO4 2H2O) is the preferred route. Microorganisms of the natural iron cycle living at pH below 2 and high temperatures can conduct the oxidation of ferrous iron with oxygen, which is not feasible chemically at these extreme conditions. Remarkably, at similar acidic conditions and high temperature these microorganisms can also carry out the oxidation of arsenite (As(III)) to arsenate (As(V)). Using these intrinsic features of the microorganisms, we have investigated the role of a thermoacidophilic mixed culture in the oxidation of As(III) and precipitation of (As(V) in the form of scorodite from a synthetic wastewater containing 6.7mM of As(III) and 0.5%Wt pyrite as main iron Fe(II) source. The results indicate that As(III) was completely oxidized from the synthetic wastewater in the presence of pyrite and scorodite was formed only in presence of the mixed culture at a Fe/As:1.3. This is a combination of biological oxidation and biocrystallisation accomplished to the presence of pyrite not only as the main energy source for the microorganisms, but as catalyst in the As(III) oxidation reaction.
Column Bioleaching of a Saline, Calcareous Copper Sulfide Ore
Authors: Pakostova Eva , Grail Barry M. , Johnson D. Barrie
Published: August 2017

“Deep in situ biomining”, widely considered to be a potentially environmentally-benign and cost effective biotechnology for extracting and recovering base metals from deep-buried base metal deposits, is being developed within the EU Horizon 2020 project “BioMOre”. Data are presented from non-aerated column experiments in which a saline, calcareous copper-rich ore (kupferschiefer) was subjected to a three-stage eaching protocol: (i) with water, to remove soluble salts; (ii) with sulfuric acid, to remove calcareous minerals and other acid-soluble salts; (iii) indirect bioleaching with a microbiologically-generated ferric iron lixiviant. Sequential leaching with water and acid removed ~85% of the chloride prior to bio-processing, while ~13% of the copper present in the ore was leached using sulfuric acid, and a further 39 - 59% by the lixiviant.
Bioleaching for Removal of Chromium and Associated Metals from LD Slag
Authors: Thallner Sophie , Hemmelmair Christine , Martinek Silvia , Schnitzhofer Wolfgang
Published: August 2017

The ability of Acidithiobacillus ferrooxidans to remove chromium and other metals from LD slag was examined. Additionally the option to retrieve P from LD slag was evaluated. Due to the facts that A. ferrooxidans is a facultative anaerobic microorganism and LD slag is an alkaline and oxidic material, both oxidative and reductive bioleaching experiments were carried out. In the reductive mode, four different gas atmospheres (nitrogen, carbon dioxide, air and a mixture of N2 and CO2) were considered. Promising results were obtained by reductive bioleaching with A. ferrooxidans and a pure carbon dioxide atmosphere, 83 % chromium could be removed. In comparison, only 27 % Cr were removed by oxidative bioleaching. The degree of P removal could not be easily determined due to imbalanced data obtained.
Reduction of Iron(III) Ions at Elevated Pressure by Acidophilic Microorganisms
Authors: Zhang Rui Yong , Hedrich Sabrina , Schippers Axel
Published: August 2017

A composed mixed acidophilic, iron-oxidizing culture (FIGB) and a thermo-acidophilic enrichment culture (TK65) were used to evaluate microbial iron(III) reduction coupled to oxidation of reduced inorganic sulfur compounds (RISCs) under high pressure. Experiments were done in batch culture in high pressure vessels at 1 and 100 bar. Microbial abundance and activity were determined by measuring iron(II) concentration, direct cell counting, T-RFLP and quantitative real-time PCR. The data indicate that both cultures are able to reduce soluble iron(III) by oxidation of sulfur compounds under anaerobic conditions. At high pressure (100 bar) these acidophiles were capable of growing and microbial ferric iron reduction was only partially inhibited. These results indicate that acidophiles can be barotolerant and their activities are contributing to sulfur and iron cycling in anaerobic environments including deep ore deposits which is highly relevant for in situ leaching operations.
Bio-Heap Leaching of Primary Copper Sulfide Ore by JOGMEC
Authors: Shinkawa Tatsuya , Chida Tadashi , Furukawa So , Kamiya Taro
Published: August 2017

JOGMEC has been carrying out the study on primary copper sulfide ores leaching for recovering copper economically and efficiently by heap leaching. In our study, we have been using the primary copper sulfide ore produced in an IOCG deposit. The ore is characterized by high iron content and high acid consumption in leaching. For the optimization of the leaching, the conditions such as ore size, agglomeration, pH and irrigation rate of leaching solution were examined with column leach tests. The best result was over 80 % extraction of copper in 150 days with leaching solution of 1 M sulfuric acid and temperature of 45 °C. In this experiment, the fines of the ore sample were removed before putting it into the column to keep the permeability of the ore bed. In these column leach tests, the Fe2+/total-Fe ratio of PLS decreased gradually by the activity of naturally grown iron-oxidizing bacteria. The bacteria in PLS, which have the ability of iron-oxidizing and sulfur-oxidizing, were identified by next-generation sequencing as Acidithiobacillus caldus and Sulfobacillus thermosulfidooxidans. We also carried out bench-scale tests with about 200 tons of the primary copper sulfide ores. Iron-oxidizing and sulfur-oxidizing bacteria were identified in the leaching solution as same with column leach tests. It is considered that the bacteria worked in the leaching solution and on the surface of the ores.
On the distortions in calculated GW parameters during slanted atmospheric soundings
Authors: de la Torre Alejandro , Alexander Peter , Schmidt Torsten , Llamedo Pablo , Hierro Rodrigo
Published: August 2017

Abstract. The significant distortions introduced in the measured atmospheric gravity wavelengths by soundings other than in vertical and horizontal directions, are discussed as a function of elevation angle of the sounding path and the gravity waves aspect ratio. Under- or overestimation of real vertical wavelengths during the measurement process depends basically on the value of these two parameters. The consequences of these distortions on the calculation of the energy and vertical flux of horizontal momentum are analyzed and discussed in the context of two experimental limb satellite setups: GPS-LEO radio occultations and TIMED/SABER measurements. Possible discrepancies previously found between the momentum flux calculated from satellite temperature profiles, on site and from model simulations, may, to a certain degree, be attributed to these distortions. A recalculation of previous momentum flux climatologies based on these considerations seems to be a difficult goal.
Comparison of land surface humidity between observations and CMIP5 models
Authors: Dunn Robert J. H. , Willett Kate M. , Ciavarella Andrew , Stott Peter A.
Published: August 2017

Abstract. We compare the latest observational land surface humidity dataset, HadISDH, with the latest generation of climate models extracted from the CMIP5 archive and the ERA-Interim reanalysis over the period 1973 to present. The globally averaged behaviour of HadISDH and ERA-Interim are very similar in both humidity measures and air temperature, on decadal and interannual timescales. The global average relative humidity shows a gradual increase from 1973 to 2000, followed by a steep decline in recent years. The observed specific humidity shows a steady increase in the global average during the early period but in the later period it remains approximately constant. None of the CMIP5 models or experiments capture the observed behaviour of the relative or specific humidity over the entire study period. When using an atmosphere-only model, driven by observed sea surface temperatures and radiative forcing changes, the behaviour of regional average temperature and specific humidity are better captured, but there is little improvement in the relative humidity. Comparing the observed climatologies with those from historical model runs shows that the models are generally cooler everywhere, are drier and less saturated in the tropics and extra-tropics, and have comparable moisture levels but are more saturated in the high latitudes. The spatial pattern of linear trends is relatively similar between the models and HadISDH for temperature and specific humidity, but there are large differences for relative humidity, with less moistening shown in the models over the tropics and very little at high latitudes. The observed drying in mid-latitudes is present at a much lower magnitude in the CMIP5 models. Relationships between temperature and humidity anomalies (T–q and T–rh) show good agreement for specific humidity between models and observations, and between the models themselves, but much poorer for relative humidity. The T–q correlation from the models is more steeply positive than the observations in all regions, and this over-correlation may be due to missing processes in the models. The observed temporal behaviour appears to be a robust climate feature rather than observational error. It has been previously documented and is theoretically consistent with faster warming rates over land compared to oceans. Thus, the poor replication in the models, especially in the atmosphere-only model, leads to questions over future projections of impacts related to changes in surface relative humidity. It also precludes any formal detection and attribution assessment.
Fractional Brownian motion, the Matérn process, and stochastic modeling of turbulent dispersion
Authors: Lilly Jonathan M. , Sykulski Adam M. , Early Jeffrey J. , Olhede Sofia C.
Published: August 2017

Abstract. Stochastic processes exhibiting power-law slopes in the frequency domain are frequently well modeled by fractional Brownian motion (fBm), with the spectral slope at high frequencies being associated with the degree of small-scale roughness or fractal dimension. However, a broad class of real-world signals have a high-frequency slope, like fBm, but a plateau in the vicinity of zero frequency. This low-frequency plateau, it is shown, implies that the temporal integral of the process exhibits diffusive behavior, dispersing from its initial location at a constant rate. Such processes are not well modeled by fBm, which has a singularity at zero frequency corresponding to an unbounded rate of dispersion. A more appropriate stochastic model is a much lesser-known random process called the Matérn process, which is shown herein to be a damped version of fractional Brownian motion. This article first provides a thorough introduction to fractional Brownian motion, then examines the details of the Matérn process and its relationship to fBm. An algorithm for the simulation of the Matérn process in O(NlogN) operations is given. Unlike fBm, the Matérn process is found to provide an excellent match to modeling velocities from particle trajectories in an application to two-dimensional fluid turbulence.
Study of ferroelastic behavior and microstructure in polycrystalline
LaCoO3 using Transmission Electron Microscopy
Authors: Kell S. , Tanase M. , Klie R.F.
Published: August 2017

LaCoO3 is a ferroelastic perovskite-type oxide. It has been shown to
undergo creep at room temperature. LaCoO3 responds to stress by changing its
domain structure, resulting in formation of spontaneous strain. The
microstructure of a sample of polycrystalline LaCoO3 with history of stress
was investigated using Transmission Electron Microscopy (TEM). It was
compared to an unstrained sample to determine what changes are produced. TEM
analysis has shown an increase in defect density as well as the appearance
of atomic scale ordering. The causes of the observed ordering and their
relation to ferroelastic behavior are explored.
Interaction of Hydrogen on a Lanthanum hexaboride 111 Surface
Authors: Cameli J. , Tillekaratne A. , Trenary M.
Published: August 2017

In order to sustain society's current level of energy consumption and
prevent irreversible climate degradation due to the greenhouse effect an
alternative energy carrier is required. The aim of this experiment was to
determine the conditions under which a lanthanum hexaboride (LaB6) surface
would form boron-hydrogen (B-H) bonds when exposed to hydrogen. Reflection
absorption infrared spectroscopy (RAIRS) was used to confirm formation of
bonds and X-ray photoelectron spectroscopy (XPS) and low energy electron
diffraction (LEED) were used to characterize the surface. Upon completion of
the experiment no B-H bonds were found to form under the conditions tested.
However, it is believed that the bond formation may have been impeded by
tungsten contamination of the surface or may have been due to the
instability of the B-H bond. A lower temperature could be required for their
formation.
Investigation of flow through P[NIPAM/MMA] copolymer coated glass
capillary tubes, and glass copolymer adhesion improvements with hydrofluoric
acid etching
Authors: Wiegmann R. , Zhang Y. , Yarin A.
Published: August 2017

This study aims to display the retention of the thermo-responsive
properties of the copolymer poly(N-isopropyl acrylamide-methyl methacrylate)
[P(NIPAM/MMA)] when coated on the inner diameter of a glass capillary tube,
and to prove the stability of the copolymer coating when subjected to
pressure driven fluid flow. The study shows that the fluid flow through such
a capillary tube follows Hagen-Poiseuille flow. Furthermore, this study
examines methods of improving polymer adhesion to glass by hydrofluoric acid
etching. Such a coated tube system is applicable in drug delivery, self
cleaning tubes, and microelectromechanical systems (MEMS).
Comprehensive JP8 Mechanism for Vitiated Flows
Authors: Hall K.M. , Fu X. , Brezinsky K.
Published: August 2017

With the intent of optimizing the combustion process of complex
hydrocarbon liquid fuels such as JP8 in internal combustion jet engines and
their afterburners, simpler surrogate hydrocarbon compounds were used in a
counterflow diffusion flat flame burner to validate the chemical kinetic
modeling process. The combustion products sampled from the flame produced
during the burning of the validation fuels methane and n-heptane were
analyzed using a Varian CP3800 gas chromatograph. The effects of sampling
with a 350 micron outer diameter (OD) fused-silica tube were compared to
those of a 3.5 mm quartz probe in order to minimize sampling effect on the
flame. Simulations of the sampled species were performed using the OPPDIF
package of CHEMKIN with chemistry models provided by UIC. Concentrations of
major species (e.g. CO, CH4, CO2, O2) were found to be well simulated with
the models, with the best fit occurring for methane and n-heptane, and wider
variation occurring with some species in all validation fuels.
Electric Vehicle Batteries: Li-ion and Beyond, Challenges and
Advancements
Authors: KC B.
Published: August 2017

Batteries are key to developing affordable Electric Vehicle (EV).
However, EVs have not yet come on par with gasoline vehicles in many areas
such as price, driving range, and recharge time. Many research areas are
actively seeking to improve the current market dominant lithium-ion
batteries (LIBs) as well as find alternatives to LIBs. This review will look
at current status of LIBs, a few alternatives, and collective challenges and
advancements associated with these batteries.
Social Equity in the Smart Grid
Authors: Patel D.
Published: August 2017

Power grids are under pressure to meet the growing demand for
electricity within a stable and sustainable distribution system. These
challenges drive the evolution of smart grids. The smart grid involves
various forms of technology, specifically advanced metering infrastructure
(AMI). Deployment of AMI technologies, by utility companies, is rolling out
all over the United States of America (U.S.). However customers have not
been using the technologies to its full potential. Engaging communities,
particularly lower income communities, to take full advantage of AMI
technologies is an important first step in building social equity through
the smart grid. Increasing resiliency of the grid infrastructure in these
communities provides opportunities for strategic rebuilding, eective carbon
drawdown, and opportunities for jobs creation.
Estudo Comparativo entre aplicativos turísticos móveis
Authors: Estaregue Daniela , Gonçalves Berenice Santos , Gonçalves Marilia Matos
Published: August 2017

O turismo é um dos segmentos econômicos que tem apresentado crescimento no mundo dos negócios. Esse crescimento apoia-se em muitos fatores que se inter-relacionam, entre eles, estão os avanços tecnológicos (PAGE, 2011). A crescente demanda turística gera a necessidade de ampliação das fontes de informações. Sendo assim, as tecnologias têm favorecido a troca de conhecimento e possibilitando o intercâmbio de informações em tempo real apoiando de diferentes modos a atividade turística. A partir de aplicativos móveis pode-se ter conhecimento do local de destino com um maior grau de interação. Assim, este trabalho teve o objetivo de desenvolver um estudo comparativo, no ano de 2016, entre os aplicativos mais baixados em 2012 segundo documento apresentado pela Sociedade Estatal para a Gestão da Inovação e das Tecnologias Turísticas - SEGITTUR (ESPANHA, 2013). A partir deste estudo, identificou-se as principais ferramentas disponibilizadas por tais aplicativos e verificou-se como estava sendo utilizado o potencial da tecnologia móvel. De um modo geral, constatou-se que a utilização desses aplicativos estava facilitando o processo da viagem, porém não foram encontradas ferramentas que ampliassem a experiência turística, ou seja, que combinassem a informação real com o conteúdo digital.