bluuebunny/crossref_metadata_2025 huggingface dataset:
In Situ Characterization and Molecular Mechanisms Evaluation of Interfacial Interaction between Minerals and Bioleaching Microorganisms
Authors: Xia Jin Lan , Liu Hong Chang , Nie Zhen Yuan , Liu Li Zhu , Zhu Hong Rui , Wang Lei , Yang Yun , Ma Ya Long , Pan Xuan , Zhao Yi Dong , Ma Chen Yan , Zheng Lei , Zhen Xiang Jun , Zhang Li Juan , Wen Wen
Published: August 2017

This article presents as follows the most recent progresses of our group on in-situ characterization and evaluation of the molecular mechanisms of interfacial interaction of minerals and bioleaching microorganisms. (1) By studying the speciation transformation of iron/copper/sulfur on the mineral surface, the evolution of cell surface properties and EPS composition, the evolution of microbial community structure, and the evolution of expression of key oxidase genes during bioleaching, to characterize the adaptation process and therein the effects of it on the specific sulfur oxidation efficiency of bioleaching; (2) by in-situ characterization of the evolution of chalcopyrite surface microstructure, chemical speciation and the biofilm formation, to illustrate the specific adsorption and the relationship between cell growth/biofilm formation and the structure and speciation on the defect mineral surface; (3) by studying the utilization, transformation and activation of S0, which is one of the major intermediates during bioleaching, and the distribution of extracellular thiol groups and iron speciation, to evaluate in situ the sulfur activation mechanism; and (4) by comparative proteomics study of the extracellular and outmembrane proteins and looking up the genome sequence, to screen sulfur activation/transportation relevant proteins and genes.
Mineral Specific Biofilm Formation of “Acidibacillus ferrooxidans” Huett2
Authors: Schieferbein Franziska , Bauer Matthias , Klingl Andreas , Schopf Simone
Published: August 2017

Recently, a novel acidophilic heterotrophic iron oxidizing bacterium belonging to the newly described genus Acidibacillus (formerly Alicyclobacillus) was isolated from a water drainage ditch in Freiberg, Germany. Bioleaching tests showed that Acidibacillus ferrooxidans Huett2 contributes to the dissolution of minerals. As microbe-mineral interactions play a crucial role in nature and enhance the reaction kinetics of the mineral dissolution, attachment of Ab. ferrooxidans Huett2 on the sulfide minerals pyrite (FeS2), chalcopyrite (CuFeS2), and chalcocite (Cu2S) is in the focus of our current investigations.
Adhesion Studies of Microorganisms on Natural Ore Material
Authors: Eisen Nadja , Straube Felix , Schopf Simone , Schlömann Michael
Published: August 2017

In the course of the decline of high-grade ore deposits, new effective and eco-friendly bioleaching techniques are of interest. In-situ leaching is an auspicious method, but composition of leaching community should be adapted to the respective external conditions and the ore material. In this study several sulfidic minerals were inoculated into acidic mine water of a mine in eastern Germany, housing members of well-known iron oxidizing bacteria like Acidithiobacillus, Leptospirillum and Ferrovum. The attachment tests were performed in batch and in a continuous way at different temperatures. The analysis of the extracted DNA from adhered cells showed an enrichment of Ferrovum spp. on chalcopyrite surface under in-situ conditions at 11°C. For laboratory batch conditions an accumulation of Leptospirillum spp. was detected for adhered cells probably due to the changes of the physicochemical parameter of the mine water. In more detailed analyses we aim to elucidate possible preferential attachment of the mine water community members to certain minerals.
Introduction to High-Throughput Sequencing Technologies and Review of its Application in Bioleaching
Authors: Lei Pang , Gan Min , Yang Bao Jun , Liu Xue Duan , Yang Shuang Bo , Zhou Shuang
Published: August 2017

Over the past years, the traditional cultivation-independent genomic approaches which rely on the preexisting knowledge about gene sequence, have significantly promoted our understanding of the structural and functional diversity of bioleaching microorganisms in extremely acidic environments. However, high-throughput sequencing technology as a comprehensive and rapid method is now being ported to bioleaching systems for microbial community and gene expression analysis. Years of research have demonstrated that high-throughput sequencing technology has the potential to dramatically accelerate biological research, by enabling the comprehensive analysis of genomes and transcriptomes. This paper aims to introduce the high-throughput sequencing methodology, particularly focusing on the application of high-throughput sequencing technology on bioleaching microorganisms and the challenges associated with its applications.
Potential Bioleaching Effects in In Situ Recovery Applications
Authors: Richter Constanze , Kalka Harald , Märten Horst
Published: August 2017

The potential role of microorganisms in the in-situ recovery (ISR) of technology metals, in particular from reduced ores, is not well understood, but attracts increasing interest worldwide. Based on the feasibility criteria for ISR applications in general, effects of biota on kinetic rates of leaching are systematized. The indirect catalysis of leaching by microbial (re-)oxidation of Fe2+ to Fe3+ as directly acting e- acceptor is a well verified mechanism, however, for practical applications this requires the availability of an oxidant in the leachant. The ex-situ bio-oxidation of Fe in an aerated bioreactor is considered as an alternative. Reactive transport simulations of ISR from sulfidic Cu ores based on kinetic rates as function of pH and oxidation potential (concentration of e- acceptors) in comparison with thermodynamically driven metal dissolution (constrained by oxidation potential) demonstrate the key parameters for (bio-)leaching productivity.
Evolution of Compositions and Contents of Capsule and Slime EPSs for Adaptation to and Action on Energy Substrates and Heavy Metals by Typical Bioleaching Microorganisms
Authors: Nie Zhen Yuan , Liu Hong Chang , Xia Jin Lan , Liu Huan , Cui Yun Lu , Qiu Guan Zhou
Published: August 2017

Adaption to the energy substrates and heavy metals by bioleaching micoorganisms is the prerequisite for efficient microbe-mineral interaction in bioleaching process. It is known extracellular polymer substances (EPSs) take important role in mediating the adaption to and action on energy substrates and heavy metals. This report presents the evolution of compositions and contents of the major components of EPSs of the typical bioleaching microorganisms (Acidithiobacillus ferrooxidans, Leptospirillum ferriphilum, Sulfobacillus thermosulfidooxidans, and Acidianus manzaensis,) exposed to different energy substrates and heavy metal ions. These strains were acclimated firstly to Fe2+ substrate, and then on the substrates elemental sulfur (S0), pyrite and chalcopyrite, respectively. It was found that the major components of capsule and slime EPSs in terms of proteins, polysaccharides, as well as uronic acids were quite different in contents for the Fe2+-acclimated strains, and they even changed more when the Fe2+-acclimated strains were further acclimated to the other substrates. When exposed to heavy metals, all strains demonstrated much decrease in contents of capsule EPSs, and much increase in slime EPSs contents and the heavy metals were found to bound to the slime parts. It was for the first time the EPSs of the bioleaching strains were fractionated into capsule part and slime part, and it was also for the first time we found the differences in evolution of compositions and contents of the major organic components as well as the inorganic matter of capsule EPSs and slime EPSs when the bioleaching strains were exposed to different energy substrates and heavy metals.
Effect of Galactose on EPS Production and Attachment of Acidithiobacillus thiooxidans to Mineral Surfaces
Authors: Aguirre Paulina , Sánchez Rodríguez Aminael , Gentina Juan Carlos , Schippers Axel
Published: August 2017

The presence of extracellular polymeric substances (EPS) and their relevance for biofilm formation on the mineral surface for a variety of microbial species play a fundamental role in the degradation of sulfide ores. EPS production is associated with induction or auto induction mechanisms as a response of bacteria to environmental conditions. In this study, we tested galactose as an inducer of EPS production in planktonic cells of Acidithiobacillus thiooxidans DSM 14887T and their adherence to polymetallic mineral surfaces. Cells of At. thiooxidans were first adapted to grow at different concentrations of galactose (0.15, 0.25, 0.35%) using a modified 9K liquid medium and elemental sulfur as the energy source. In order to determine EPS production, the microorganisms were grown for 24 hours at different concentrations of galactose. Our results showed a cell adherence of 84% cells within 4 hours in presence of 0.15% galactose compared to 70% without galactose. The optimal concentration of galactose for maximal EPS production was 0.25% and for the attachment of cells it was 0.15%. Higher galactose concentrations inhibited microbial growth and decreased the number of cells attached to the mineral. While with a small amount of galactose in the culture media can shift the balance between sessile cells and planktonic cells, generating an increase in adhesion and therefore a possible increase of the bioleaching rate.
EIS Studies of Chalcopyrite Involving Iron(II) Ions
Authors: Delfino Fabiana Antonia Arena , Bevilaqua Denise , Benedetti Assis Vicente
Published: August 2017

In this work, we present an Electrochemical Impedance Spectroscopy (EIS) study using a carbon paste electrode modified with chalcopyrite (CuFeS2) containing 50 wt% of the mineral (particle size < 38 μm) and graphite (particle size < 20 μm) in naturally aerated salt acid solutions (pH 1.8) without and with the addition of 0.100 mol L-1 of ferrous ions. The aim was to evaluate the influence of the solution potential on the behavior of chalcopyrite electrode in the presence and absence of iron (II) ions. Additionally, we evaluated the influence of the bacteria Acidithiobacillus ferrooxidans in the system containing iron (II) ions without applying potential. Therefore, EIS was used to investigate the processes occurring at the electrode/solution interface in the different systems, considering the charge transfer reactions involving chalcopyrite and ferrous ions, the presence of a multicomponent layer, and diffusion. The results showed that the combination of iron (II) ions with the imposition of low potential values (0.100 Fe2+ ions with +0.300 V/Ag|AgCl|KCl3mol/L) activates the chalcopyrite surface and enhances the copper recovery.
Gallium Mobilization in Soil by Bacterial Metallophores
Authors: Schwabe Rïngo , Obst Britta , Mehnert Marika , Tischler Dirk , Wiche Oliver
Published: August 2017

In the present study we explore the idea of biotechnologically produced metallophore mixtures as selective chelating compounds for economically valuable metals from various sources. A complex soil matrix with natural levels of metal mineralization was employed as a potential source of metals. We focused on gallium-chelating metallophore preparations of two soil bacteria (Gordonia rubripertincta CWB2 and Paracoccus denitrificans PD1222) which were compared to the commercially available desferrioxamine B (DFOB). As a reference, the binding of iron was analyzed. The herein described successful mobilization of metals such as gallium from soil provides first hints towards alternative strategies, such as phytomining, sensor development, or solvent extraction based on metallophores. The metallophore mixture produced by the strains showed best results at pH 8 and allowed to mobilize gallium about three times better as the pure commercially available DFOB.
On the Immobilization of Desferrioxamine-Like Siderophores for Selective Metal Binding
Authors: Anke Marlene Kirstin , Szymańska Katarzyna , Schwabe Rïngo , Wiche Oliver , Tischler Dirk
Published: August 2017

Gordonia rubripertincta CWB2 produces hydroxamate-type siderophores. Therefore it was cultivated under iron limitation. Analytical reversed-phase HPLC allowed determining a single peak of ferric iron chelating compounds from culture broth. The elution profile and its absorbance spectrum were similar to those of desferrioxamine B. The latter is a commercial available metal chelating agent which is of interest for industries. We successfully developed an HPLC protocol to separate metal-free and metal-loaded desferrioxamines. Further, we aimed to increase the re-usability of desferrioxamines as metal chelators by immobilization on silica based carriers. The siderophores of strain CWB2 have been covalently linked to the carrier with a high yield (up to 95%). Metal binding studies demonstrated that metals can be bound to non-immobilized as well as to the covalently linked desferrioxamines.
An XPS and XANES Study on the Bioleaching of Arsenopyrite with or without Pyrite
Authors: Yang Yi , Liu Wei Hua , Wang Chun , Chen Miao , Ram Rahul , Bhargava Suresh K.
Published: August 2017

In the present study, we investigated the bioleaching of arsenopyrite with or without pyrite by moderate thermophiles. In both chemical leaching and bioleaching, the addition of pyrite decreased the leaching rate of arsenopyrite. The arsenic speciation and minerology changes in the residues were analysed by X-ray Absorption Near Edge Structure (XANES) Spectroscopy, X-ray Photoelectron Spectroscopy (XPS) and powder X-ray Diffraction (XRD). The XANES analysis showed no detectable arsenopyrite in the final residues from the experiments without pyrite. However, there was still 21.7% of arsenic species presented as arsenopyrite after bioleaching, when the initial arsenopyrite/pyrite ratio was 1:5. The XPS analysis revealed there was only As(V) on the surface of most of the residues, except on one chemically leached sample where As(III) was found.
Chemical vs. Biological Crystals, all the Same?
Authors: Weijma Jan , Gonzàles-Contreras Paula , Buisman Cees N.J.
Published: August 2017

Using microorganisms to mediate crystallisation of metals and minerals in open-culture bioreactors has potential to recover recyclable materials from dilute aqueous streams, but also to prevent their emission to the environment. Although this potential is already exploited in practice to some extent, biological crystallization for metal recovery is still largely a black box technology with limited understanding of the role of the microorganisms in the crystallization, and the differences with chemical crystallisation. Using biocrystallisation of scorodite (FeAsO4.2H2O) and sphalerite (ZnS) as examples we propose that the role of microorganisms strongly depends on established saturation state of the solution. For scorodite, microorganisms are used to exert control over the crystallization as their ferrous iron-oxidizing activity keeps the solution slightly oversaturated. Also, the oversaturation level is kept homogeneous because of continuous biological formation of the reactant ferrous iron throughout the solution. In continuous bioreactor experiments on which we reported previously, scorodite crystal sizes still increased after 72 days of bioreactor operation indicating that indeed crystal growth was favored over nucleation. On the other hand, in our experiments with zinc sulfide, crystallization proceeded in highly oversaturated solutions in a continuous sulfate reducing bioreactor fed with a zinc sulfate solution and H2/CO2 as electron donor and carbon source. The high oversaturation likely resulted in dominant primary nucleation in the bulk solution, with little or no control over crystal growth, even though agglomeration may still have occurred. This was exemplified by particle sizes which decreased in the bioreactor experiment and remained stable after already about 2 weeks of operation.
Evaluation of Long-Term Post Process Inactivation of Bioleaching Microorganisms
Authors: Bomberg Malin , Miettinen Hanna , Wahlström Margareta , Kaartinen Tommi , Ahoranta Sarita , Lakaniemi Aino Maija , Kinnunen Päivi
Published: August 2017

The H2020 BioMOre project (www.biomore.info, Grant Agreement #642456) tests the feasibility of in-situ bioleaching of copper in deep subsurface deposits in the Rudna Mine, Poland. Copper is leached using biologically produced ferric iron solution, which is recycled back to the in-situ reactor after re-oxidation by iron-oxidizing bacteria (IOB). From a post operational point of view, it is important that the biological processes applied during the operation can be controlled and terminated. Our goal was to determine the possibility to use natural saline mine water for the inactivation of introduced IOB remaining in the in-situ reactor after completion of the leaching process of the Kupferschiefer ore. Aerobic and anaerobic microcosms containing acid-leached (pH 2) sandstone or black shale from the Kupferschiefer in the Rudna mine were further leached with the effluent from an iron-oxidizing bioreactor, at a temperature of 30°C, for 10 days, to simulate in-situ leaching. After the removal of the iron solution, residing IOB were inactivated by filling the microcosms with saline water (65 g L-1 Cl-) originating from the mine. The saline water completely inactivated the IOB and the naturally occurring saline water of the mine can be used for long-term post process inactivation of bioleaching microorganisms.
Rare Earth Elements Recovery and Sulphate Removal from Phosphogypsum Waste Waters with Sulphate Reducing Bacteria
Authors: Mäkinen Jarno , Bomberg Malin , Salo Marja , Arnold Mona , Koukkari Pertti
Published: August 2017

Phosphogypsum waste, originating from phosphoric acid production from apatite ores, is well known for its high production rate and possible release of sulphate-rich seepage waters. In addition to negative environmental impacts, phosphogypsum waste heaps are also remarkable secondary sources of Rare Earth Elements (REE); in the phosphoric acid production process a majority of REE, occurring in apatite, are precipitated to the phosphogypsum waste. Therefore, a method treating both sulphate-rich waters and recovering REE from phosphogypsum heaps and seepage waters would offer both economic and environmental benefits. In this ongoing study, seepage waters from a phosphogypsum heap are treated with Sulphate Reducing Bacteria (SRB) and ethanol as a substrate. Sulphate is first reduced to hydrogen sulphide, which then precipitates REE as sulphides. The main challenge, low concentration of REE in seepage waters (e.g. 2.87 μg/l La, 5.13 μg/l Ce, 0.67 μg/l Y and 3.32 μg/l Nd), is overcome by utilizing continuous mode, semi-passive and cost effective column apparatus, requiring no agitation and performing both sulphate reduction and REE recovery in a single reactor. The SRB method results in a sulphate reduction rate of 40-80 % (from app. 1400 mg/l to 276-844 mg/l sulphate in the effluent) and efficient REE recovery from seepage water. The concentrate obtained from the column consists of a mixture of anaerobic sludge and precipitated REE, with respective REE concentrations of 202 mg/kg La, 477 mg/kg Ce, 49 mg/kg Y and 295 mg/kg Nd.
Bioleaching of Copper Slag Material
Authors: Schippers Axel
Published: August 2017

Bioleaching is applied mainly for copper recovery from low-grade sulfide ores via heap leaching. The main copper processing route includes pyrometallurgy and the remaining copper slag from smelting may still contain copper in amounts found in the ore. Here bioleaching of copper slag material with a copper content of about 1 % (grain size < 63 µm) and fayalite (Fe2SiO4) und magnetite (Fe3O4) as main mineral phases was tested in aerobic shake flask experiments with a mixed culture of Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans and Acidiphilium spp..To additionally test for reductive bioleaching, experiments under anaerobic conditions (80% N2, 20% CO2, v/v) with or without addition of elemental sulfur were run. The pH was adjusted to < 3 by addition of sulfuric acid. After the incubation period of more than 50 days at 30°C cell growth was observed in all biological assays. The redox potential was above 800 mV SHE in the aerobic biological assays and dropped to around 500 mV in the chemical control assays as well as in the anaerobic biological and chemical assays. A significant copper bioleaching was observed in the aerobic experiments with 91 % copper release (max. 35 % in the chemical controls). Anaerobic bioleaching experiments did not show a significant copper release, however the release of iron (as iron(II)) and sulfate was much higher than in the abiotic assays and several fold higher than in the classical aerobic bioleaching experiments. Overall the results show that copper bioleaching from slag material is possible, however the economic feasibility needs to be demonstrated.
Bioleaching of Cadmium from Contaminated Paddy Fields by Consortium of Autotrophic and Indigenous Cadmium-Tolerant Bacteria
Authors: Deng Yan , Liu Xue Duan , Liu Hong Wei , Jiang Hui Dan , Xu Liang Feng , Xiao Yun Hua , Hao Xiao Dong , Yin Hua Qun , Liang Yi Li
Published: August 2017

It has been a major issue for urgent solution in China as a result of a series of poisoning cases caused by cadmium. Yet there is no effective methods for removal of cadmium from the paddy soils. Microbial leaching process as an effective approach is currently applied to remediate the contaminated soils. In this study, bioleaching of cadmium from contaminated paddy soils by consortium of autotrophic and indigenous cadmium-tolerant bacteria was applied. The bioleaching results showed that the leaching rate of cadmium was from 74.93% to 92.76%. The distribution of the Cd fractions had a significant change before and after bioleaching with the organic fraction and residues fraction mainly remained. Moreover, the microbial community analysis showed that the Acidithiobacillus and Acidiphilium became the dominant genus in the bioleaching process. The combination of bioleaching with acidophilic chemolithotrophic microorganisms and the cadmium-resistant bacteria provides a potential process for bioremediation of metal-contaminated soils.
Investigation of the Ga Complexation Behaviour of the Siderophore Desferrioxamine B
Authors: Jain Rohan , Cirina Francesca , Kaden Peter , Pollmann Katrin
Published: August 2017

Gallium (Ga) is a critical element for the electronic industry, however, its long-term supply is not assured. Thus, the recovery of Ga from industrial wastewaters is important. Selective sorption is a recommended technology for the recovery of Ga from industrial wastewaters, however, selective sorbents are elusive. Desferrioxamine B (DFOB), a hydroxomate siderophore that is known to be highly selective towards Fe3+, is tested for its ability to complex Ga. This study demonstrated that DFOB forms 1:1 complex with Ga and the maximum Qe-Ga is 124.4 mg of Ga complexed per g of DFOB. Further, the complexation mechanism of Ga3+ and Fe3+ with DFOB is similar, as indicated by NMR, suggesting that the selectivity of DFOB towards Fe3+ will be extended to Ga3+ as well. Thus, DFOB seems to be a suitable candidate for the sorption of Ga from industrial wastewaters.
Microbiological As(III) Oxidation and Immobilization as Scorodite at Moderate Temperatures
Authors: Era Yuta , Hirajima Tsuyoshi , Sasaki Keiko , Okibe Naoko
Published: August 2017

The potential utility of mesophilic/moderately thermophilic acidophiles was investigated for immobilization of arsenic (As) as scorodite (FeAsO4·2H2O) at moderate temperatures (35–45 °C). Here, the acid-tolerant mesophile Thiomonas cuprina Hö5 and acidophilic moderately thermophile Acidimicrobium ferrooxidans ICP were selected as As (III)- and Fe (II)- oxidizers, respectively. Due to a difference in their optimal growth pHs, a 2-step reaction consisting of the 1st As (III) oxidation step followed by the Fe (II) oxidation + precipitation step was studied. In our previous study, the optimal [Fe (II)]ini/[As (III)]ini molar ratio for bioscorodite formation at 70 °C was shown to be around 1.4. However, setting the same molar ratio at moderate temperatures (35-45 °C) resulted in formation of unstable amorphous ferric arsenate. Lowering the ratio to ≤ 1.0 led to precipitation of crystalline bioscorodite with > 90% As (III) removal at 45 °C.
Evaluation of Substrate Consumption Kinetics in Different Support Materials for Biotrickling Filters Aiming Biogas Desulfurization
Authors: Hidalgo Letícia Ferraresi , Santos Jessyka Lima , Tayar Samir Prioto , Sarti Arnaldo , Palmieri Mauricio Cesar , Solcia Guerrero Renata de Bello , Bevilaqua Denise
Published: August 2017

Biogas is a renewable energy source that can be used to produce heat and energy, replacing fossil fuels. The main factor limiting the use of biogas is contaminants in its composition which H2S is the most important due to corrosion and environmental problems. A promising technology to remove this contaminant from biogas is the biotrickling filters and the selection of inexpensive and durable supports is an important step for the operation. This work has studied different support materials, for microorganisms immobilization, as Polyvinyl Chloride (PVC), Polyethylene Terephtalate (PET), Polytetrafluoroethylene (Teflon®) comparing to open pore polyurethane foam (OPP) each one packed in biotrickling filters to evaluate the consumption of thiosulfate by chemolitotrofic microorganisms. The kinetics of substrate consumption in different cycles for each support were distinct suggesting different microbial colonization. The materials tested have presented results very similar polyurethane foam, which has already known by its efficiency on biogas desulfurization, unless Teflon that has showed a divergent result with the increase of the substrate concentration in the system.
Optimization of Ni, Cu and Zn Recovery in Bioleaching of Electronic Scrap
Authors: Mostafavi Melika , Rashchi Fereshteh , Beikzadeh Noei Saman , Mostoufi Navid
Published: August 2017

Bioleaching was applied to mobilize metals from printed wire boards (PWBs). PWBs have a rich metal content and are produced in high volume. Operating conditions of bioleaching of PWBs using an adapted mixed culture of Acidithiobacillus ferrooxidans (A. ferrooxidans) and A. thiooxidans to recover Cu, Zn and Ni were optimized in this study. The adaptation phase began at 1 g/L PWBs powder with 10% inoculation and the final pulp density was 20 g/L after about 40 days. Optimization was performed using central composite design method to optimize four effective factors, including initial pH (1.5 to 2), pulp density (15 to 25 g/L), initial sulfur (3 to 7 g/L) and initial FeSO4 (15 to 25g/L), to achieve maximum recoveries of Cu, Zn and Ni. Also, the present study evaluated the effect of the independent variables initial pH, pulp density, initial Fe3+ concentration and initial sulfur content on extraction of metals from PWBs. Results showed that with an initial pH of 1.5, 25g/L pulp density, 25 g/L of FeSO4·7H2O and 7 g/L of S0, copper, zinc and nickel recoveries reached 92%, 96% and 94%, respectively, after 25 days.
Bioleaching of Valuable Components from a Pyrometallurgical Final Slag
Authors: Georgiev Plamen , Spasova Irena , Groudeva Veneta , Nicolova Marina , Lazarova Albena , Iliev Michail , Ilieva Ralitca , Groudev Stoyan
Published: August 2017

Pyrometallurgical copper final slag was subjected to leaching by means microbial cultures of three different groups based on their optimum temperature for growth and activity: mesophilic and moderate thermophilic bacteria, and extreme thermophilic archaea. The leaching experiments were performed by the shake-flask technique and in agitated bioreactors under batch and continuous-flow conditions. The effect of the most essential factors (particle size, pulp density, pH, aeration) on this process was studied. The highest rates of extraction of the non-ferrous metals (Cu, Zn, Co) and iron were achieved by means of some archaea but at relatively low pulp densities (5 – 10%). Some moderate thermophilic bacteria were the most efficient at the higher pulp densities (15 – 20 %). The, leaching by some mesophiles at pH 3.0 – 3.5 was also very attractive since it was connected with high extractions of these metals (about 85 – 92% at 20% pulp density), much lower acid consumption and low solubiliation of fayalite which resulted in the production of pregnant solutions suitable for the recovery of the dissolved non-ferrous metals.
Approaches for Eliminating Bacteria Introduced during In Situ Bioleaching of Fractured Sulfidic Ores in Deep Subsurface
Authors: Ballerstedt Hendrik , Pakostova Eva , Johnson D. Barrie , Schippers Axel
Published: August 2017

The major objective of the EU Horizon 2020 project “BioMOre” is the technical realization of indirect in situ leaching of Kupferschiefer sandstone and black shale ore by a ferric iron lixiviant generated by a mixed culture of autotrophic, acidophilic, iron-oxidizing bacteria and archaea in a ferric iron-generating bioreactor (FIGB). These organisms could colonize the deeply buried geological formations even under anaerobic conditions as most are able to grow by coupling the reduction of ferric iron to the oxidation of reduced sulfur compounds in the absence of oxygen. Development of an inhibition protocol to eliminate these allochthonous microbial bioreactor populations subsequent to the completion of in situ bioleaching was therefore investigated. Column bioleaching experiments using a laboratory-scale FIGB confirmed not only that metals were solubilised from both the sandstone and shale ores, but also that significant numbers of bacteria were released from the FIGB. The efficacy of 13 different chemical compounds in inhibiting microbial iron oxidation has been tested at different concentrations in shake flask and FIGB-coupled columns. Iron-oxidation activity, microcalorimetrically-determined activity and ATP measurements, in combination with microscopic cell counts and biomolecular analysis (T-RFLP, qPCR), plate counts and most-probable-number (MPN), were used to monitor the inhibiting effects on the acidophiles. Complete inhibition of metabolic activity of iron-oxidizing acidophiles was achieved in the presence of 0.4 mM formate, 300 mM chloride, 100 mM nitrate, 10 mM of primary C6 to C8 alcohols, 100 mM 1-butanol, 100 mM 1-pentanol, 0.1 mM SDS or 0.35 mM benzoic acid. No inhibition was found for 0.6 mM acetic acid and 200 mM methanol. Based on these results a recipe for the chemical composition of the “decommissioning solution” is proposed.
Religion, sex and politics: Scripting connections in Romans 1:18–32 and Wisdom 14:12–14
Authors: Punt Jeremy
Published: August 2017

Ancient people envisaged a strong link between what was deemed transgressive religious activities and objectionable sexual practices. Moreover, sexual behaviour considered aberrant was deemed to upset political boundaries which should protect civic and national stability, especially when this behaviour was suspected of effeminacy. Such thinking appears to inform both Romans 1:18–32 and Wisdom of Solomon 14:12–14. Focussing on two passages from these documents, the links between religion, sexual behaviour and politics in the context of the 1st-century Roman Empire are investigated, tracing underlying ideological intersections, connections and divergences.
Differential-free Characterisation of Smooth Mappings with Controlled Growth
Authors: Marković Marijan
Published: August 2017

In this paper we give some generalizations and improvements of the Pavlović result on the Holland–Walsh type characterization of the Bloch space of continuously differentiable (smooth) functions in the unit ball in Rm.
On the spatio-temporal representativeness of observations
Authors: Schutgens Nick , Tsyro Svetlana , Gryspeerdt Edward , Goto Daisuke , Weigum Natalie , Schulz Michael , Stier Philip
Published: August 2017

Abstract. The discontinuous spatio-temporal sampling of observations has an impact when using them to construct climatologies or evaluate models. Here we provide estimates of this so-called representation error for a range of timescales and length scales (semi-annually down to sub-daily, 300 to 50 km) and show that even after substantial averaging of data significant representation errors may remain, larger than typical measurement errors. Our study considers a variety of observations: ground-site or in situ remote sensing (PM2. 5, black carbon mass or number concentrations), satellite remote sensing with imagers or lidar (extinction). We show that observational coverage (a measure of how dense the spatio-temporal sampling of the observations is) is not an effective metric to limit representation errors. Different strategies to construct monthly gridded satellite L3 data are assessed and temporal averaging of spatially aggregated observations (super-observations) is found to be the best, although it still allows for significant representation errors. However, temporal collocation of data (possible when observations are compared to model data or other observations), combined with temporal averaging, can be very effective at reducing representation errors. We also show that ground-based and wide-swath imager satellite remote sensing data give rise to similar representation errors, although their observational sampling is different. Finally, emission sources and orography can lead to representation errors that are very hard to reduce, even with substantial temporal averaging.
Responses of surface ozone air quality to anthropogenic nitrogen deposition in the Northern Hemisphere
Authors: Zhao Yuanhong , Zhang Lin , Tai Amos P. K. , Chen Youfan , Pan Yuepeng
Published: August 2017

Abstract. Human activities have substantially increased atmospheric deposition of reactive nitrogen to the Earth's surface, inducing unintentional effects on ecosystems with complex environmental and climate consequences. One consequence remaining unexplored is how surface air quality might respond to the enhanced nitrogen deposition through surface–atmosphere exchange. Here we combine a chemical transport model (GEOS-Chem) and a global land model (Community Land Model, CLM) to address this issue with a focus on ozone pollution in the Northern Hemisphere. We consider three processes that are important for surface ozone and can be perturbed by the addition of atmospheric deposited nitrogen – namely, emissions of biogenic volatile organic compounds (VOCs), ozone dry deposition, and soil nitrogen oxide (NOx) emissions. We find that present-day anthropogenic nitrogen deposition (65 Tg N a−1 to the land), through enhancing plant growth (represented as increases in vegetation leaf area index, LAI, in the model), could increase surface ozone from increased biogenic VOC emissions (e.g., a 6.6 Tg increase in isoprene emission), but it could also decrease ozone due to higher ozone dry deposition velocities (up to 0.02–0.04 cm s−1 increases). Meanwhile, deposited anthropogenic nitrogen to soil enhances soil NOx emissions. The overall effect on summer mean surface ozone concentrations shows general increases over the globe (up to 1.5–2.3 ppbv over the western US and South Asia), except for some regions with high anthropogenic NOx emissions (0.5–1.0 ppbv decreases over the eastern US, western Europe, and North China). We compare the surface ozone changes with those driven by the past 20-year climate and historical land use changes. We find that the impacts from anthropogenic nitrogen deposition can be comparable to the climate- and land-use-driven surface ozone changes at regional scales and partly offset the surface ozone reductions due to land use changes reported in previous studies. Our study emphasizes the complexity of biosphere–atmosphere interactions, which can have important implications for future air quality prediction.
Sky radiance at a coastline and effects of land and ocean reflectivities
Authors: Kreuter Axel , Blumthaler Mario , Tiefengraber Martin , Kift Richard , Webb Ann R.
Published: August 2017

Abstract. We present a unique case study of the spectral sky radiance distribution above a coastline. Results are shown from a measurement campaign in Italy involving three diode array spectroradiometers which are compared to 3-D model simulations from the Monte Carlo model MYSTIC. On the coast, the surrounding is split into two regions, a diffusely reflecting land surface and a water surface which features a highly anisotropic reflectance function. The reflectivities and hence the resulting radiances are a nontrivial function of solar zenith and azimuth angle and wavelength. We show that for low solar zenith angles (SZA) around noon, the higher land albedo causes the sky radiance at 20° above the horizon to increase by 50 % in the near infrared at 850 nm for viewing directions towards the land with respect to the ocean. Comparing morning and afternoon radiances highlights the effect of the ocean’s sun glint at high SZA which contributes around 10 % to the measured radiance ratios. The model simulations generally agree with the measurements to better than 10 %. We investigate the individual effects of model input parameters representing land and ocean albedo and aerosols. Different land and ocean BRDFs do not generally improve the model agreement. However, consideration of the uncertainties in the diurnal variation of aerosol optical depth can explain the remaining discrepancies between measurements and model. We further investigate the anisotropy effect of the ocean BRDF which is featured in the zenith radiances. Again, the uncertainty of the aerosol loading is dominant and obscures the modelled sun glint effect of 7 % at 650 nm. Finally, we show that the effect on the zenith radiance is restricted to a few kilometres from the coast line by model simulations along a perpendicular transect and by comparing the radiances at the coast to those measured at a site 15 km inland. Our findings are relevant to, for example, ground based remote sensing of aerosol characteristics since a common technique is based on sky radiance measurements along the solar almucantar.
Determination of the refractive index of insoluble organic extracts
from atmospheric aerosol over the visible wavelength range using
optical tweezers
Authors: Shepherd Rosalie H. , King Martin D. , Marks Amelia , Brough Neil , Ward Andrew D.
Published: August 2017

Abstract. Optical trapping combined with Mie spectroscopy is a new technique used to record the refractive index of insoluble organic material extracted from atmospheric aerosol samples over a wide wavelength range with sub-nanometer resolution. The refractive index of the insoluble organic extracts was shown to follow a Cauchy equation between 460 to 700 nm for organic aerosol extracts collected from urban (London) and remote (Antarctica) locations. Cauchy coefficients for the remote sample were for the Austral summer and gave the Cauchy coefficients to be A = 1.467 and B = 1000 nm2 with a real refractive index of 1.489 at a wavelength of 589 nm. Cauchy coefficients for the urban samples varied with season, with extracts collected during summer having Cauchy coefficients of A = 1.465±0.005 and B = 4625±1200 nm2 with a representative real refractive index of 1.478 at a wavelength of 589 nm, whilst samples extracted during autumn had larger Cauchy coefficients of A=1.505 and B = 600 nm2 with a representative real refractive index of 1.522 at a wavelength of 589 nm. The refractive index of absorbing aerosol was also recorded. The technique applied in the presented study allowed the absorption Ångstrom exponent to be determined for wood smoke and humic acid aerosol extract. Typical values of the Cauchy coefficient for the wood smoke aerosol extract were A = 1.541±0.03 and B = 14800±2900 nm2 resulting in a real refractive index of 1.584±0.007 at a wavelength of 589 nm and an absorption Ångstrom exponent of 7.0. The measured values of refractive index compare well with previous monochromatic or very small wavelength range measurements of refractive index. A one-dimensional radiative-transfer calculation of the top of the atmosphere albedo was applied to model an atmosphere containing a 3 km thick layer of aerosol comprising of pure water, insoluble organic aerosol or an aerosol consisting of an aqueous core-with an insoluble organic shell. The calculation demonstrated that the top of the atmosphere albedo increases by 0.01 to 0.04 for pure organic particles relative to water particles of the same size and the top of the atmosphere albedo increases by 0.03 for aqueous core-shell particles as volume fraction of the shell material increases by 25 percent.
Technical note: An automated cirrus classification
Authors: Gryspeerdt Edward , Quaas Johannes , Goren Tom , Klocke Daniel , Brueck Matthias
Published: August 2017

Abstract. Cirrus clouds play an important role in determining the radiation budget of the earth, but many of their properties remain uncertain, particularly their response to aerosol variations and to warming. Part of the reason for this uncertainty is the dependence of cirrus clouds on the mechanism of formation, which itself is strongly dependent on the local meteorological conditions. In this work, a classification system (Identification and Classification of Cirrus or IC-CIR) is introduced to identify cirrus clouds by their formation mechanisms. Using re-analysis and satellite data, cirrus clouds are separated in four main types: orographic, frontal, convective and in-situ. Through a comparison to convection-permitting model simulations and back-trajectory based analysis, it is shown that the regimes can provide extra information on the properties and origin of cirrus that could not be provided by the retrieved cloud properties or reanalysis data alone. This classification is designed to be easily implemented in GCMs, helping improve future model-observation comparisons and leading to improved parametrisations of cirrus cloud processes.
Comparison of global datasets of sodium densities in the mesosphere and lower thermosphere from GOMOS, SCIAMACHY and OSIRIS measurements and WACCM model simulations from 2008 to 2012
Authors: Langowski Martin P. , von Savigny Christian , Burrows John P. , Fussen Didier , Dawkins Erin C. M. , Feng Wuhu , Plane John M. C. , Marsh Daniel R.
Published: August 2017

Abstract. During the last decade, several limb sounding satellites have measured the global sodium (Na) number densities in the mesosphere and lower thermosphere (MLT). Datasets are now available from Global Ozone Monitoring by Occultation of Stars (GOMOS), the SCanning Imaging Absorption spectroMeter for Atmospheric CHartography (SCIAMACHY) (both on Envisat) and the Optical Spectrograph and InfraRed Imager System (OSIRIS) (on Odin). Furthermore, global model simulations of the Na layer in the MLT simulated by the Whole Atmosphere Community Climate Model, including the Na species (WACCM-Na), are available. In this paper, we compare these global datasets.The observed and simulated monthly averages of Na vertical column densities agree reasonably well with each other. They show a clear seasonal cycle with a summer minimum most pronounced at the poles. They also show signs of a semi-annual oscillation in the equatorial region. The vertical column densities vary from 0. 5  ×  109 to 7  ×  109 cm−2 near the poles and from 3  ×  109 to 4  ×  109 cm−2 at the Equator. The phase of the seasonal cycle and semi-annual oscillation shows small differences between the Na amounts retrieved from different instruments. The full width at half maximum of the profiles is 10 to 16 km for most latitudes, but significantly smaller in the polar summer. The centroid altitudes of the measured sodium profiles range from 89 to 95 km, whereas the model shows on average 2 to 4 km lower centroid altitudes. This may be explained by the mesopause being 3 km lower in the WACCM simulations than in measurements. Despite this global 2–4 km shift, the model captures well the latitudinal and temporal variations. The variation of the WACCM dataset during the year at different latitudes is similar to the one of the measurements. Furthermore, the differences between the measured profiles with different instruments and therefore different local times (LTs) are also present in the model-simulated profiles. This capturing of latitudinal and temporal variations is also found for the vertical column densities and profile widths.
The electric current approach in the solar–terrestrial relationship
Authors: Akasofu Syun-Ichi
Published: August 2017

Abstract. The sequence of phenomena consisting of solar flares, coronal mass ejections (CMEs), auroral substorms, and geomagnetic storms is mostly a manifestation of electromagnetic energy dissipation. Thus, first of all, it is natural to consider each of them in terms of a sequence of power supply (dynamo), power transmission (electric currents/circuits), and dissipation (mostly observed phenomena), i.e., as an input–output process and the electric current line approach. Secondly, extending this concept, it is attempted in this paper to consider the whole solar–terrestrial relationship in terms of electric currents. This approach enables us to follow through not only the sequence in solar flares, auroral substorms, and geomagnetic storms but also to connect all phenomena naturally as a continuous flow of magnetic energy (V[B2∕8π]) from the sun across the magnetopause. This consideration gives some insight into all the processes involved equally well compared with the magnetic field line approach, which has been adopted almost exclusively in the past.
Tracking the direct impact of rainfall on groundwater at Mt. Fuji by multiple analyses including microbial DNA
Authors: Sugiyama Ayumi , Masuda Suguru , Nagaosa Kazuyo , Tsujimura Maki , Kato Kenji
Published: August 2017

Abstract. A two to three million tons of spring water flushes out from the foot of Mt. Fuji, the largest volcanic mountain in Japan. Based on the concept of piston flow transport, residence time of stored groundwater at Mt. Fuji was estimated at ~ 15–30 years by the 36Cl / Cl ratio (Tosaki et al., 2011). This range, however, represents the average residence time of groundwater that was mixed before it flushed out. To elucidate the route of groundwater in a given system, we determined signatures of direct impacts of rainfall on groundwater, using microbial, and stable isotopic (delta 18O), and chemical analyses (concentration of silica). Chemical analysis of the groundwater gave an average value of the water, which was already mixed with waters from various sources and routes in the subsurface environment. The microbial analysis suggested locations of water origin and paths. In situ observation during four rainfall events revealed that the stable oxygen isotopic signature obtained from spring water (at 726 m a.s.l., site SP-0m) and shallow groundwater (at 150 m a.s.l., site GW-42m), where the average recharge height from rainfall was 1500–1800 m, became greater than values observed prior to a torrential rain producing more than 300 mm of precipitation. The concentration of silica decreased after this event. In addition, the abundance of Bacteria in spring water increased, suggesting the influence of the heavy rain. Such changes did not appear when rainfall was less than 100 mm per event. The above findings indicate a rapid flow of rain through the shallow part of the aquifer, which appeared within a few weeks of the torrential rain extracting abundant microbes from soil in the studied geologic setting. Interestingly, we found that after the torrential rain, the abundance of Archaea increased in the deep groundwater at site GW-550m, ~ 12 km downstream of SP-0m. However, chemical parameters did not show any change after the event. This suggests that strengthened piston flow caused by the heavy rain transported archaeal particles from the geologic layer along the groundwater route. This finding was supported by changes in constituents of Archaea, dominated by Halobacteriales and Methanobacteriales, which were not seen from other observations. Those two groups of Archaea are believed to be relatively tightly embedded in the geologic layer and were extracted from the environment to the examined groundwater through enforced piston flow. Microbial DNA can thus give information about the groundwater route, which may not be shown by analysis of chemical materials dissolved in the groundwater.