Zinc recovery from bioleachate using a microbial electrolysis cell and comparison with selective precipitation

Metal recycling is essential for strengthening a circular economy. Microbial leaching (bioleaching) is an economical and environmentally friendly technology widely used to extract metals from insoluble ores or secondary resources such as dust, ashes, and slags. On the other hand, microbial electrolysis cells (MECs) would offer an energy-efficient application for recovering valuable metals from an aqueous solution. In this study, we investigated a MEC for Zn recovery from metal-laden bioleachate for the first time by applying a constant potential of −100 mV vs. Ag/AgCl (3 M NaCl) on a synthetic wastewater-treating bioanode. Zn was deposited onto the cathode surface with a recovery efficiency of 41 ± 13% and an energy consumption of 2.55 kWh kg−1. For comparison, Zn recovery from zinc sulfate solution resulted in a Zn recovery efficiency of 100 ± 0% and an energy consumption of 0.70 kWh kg−1. Furthermore, selective metal precipitation of the bioleachate was performed. Individual metals were almost completely precipitated from the bioleachate at pH 5 (Al), pH 7 (Zn and Fe), and pH 9 (Mg and Mn)

Dropstones in the Mar del Plata Canyon Area (SW Atlantic): Evidence for Provenance, Transport, Distribution, and Oceanographic Implications

A variety of gravel- to cobble-sized rocks, recovered from the Mar del Plata (MdP) Canyon area (Western South Atlantic at 38°S) and interpreted as ice-rafted debris, represent the first evidence that large icebergs have floated in the Falkland (Malvinas) Current from the southern polar high latitudes far northward. Detailed petrographic analyses identified the Antarctic Peninsula, sub-Antarctic islands in the Scotia Sea, and Tierra del Fuego as plausible source areas. The drift process could have started as early as at the beginning of the last deglaciation, according to an age obtained from a cold-water coral fragment associated with one of the dropstones. At the end of the Last Glacial Maximum, large icebergs have been supplied to the Antarctic Circumpolar Current, captured by those ocean current branches that circumvent the Falkland (Malvinas) Islands and entered the Argentine Margin. When the iceberg fleets approached the Brazil-Falkland (Malvinas) Confluence Zone with its steep latitudinal temperature gradient, the icebergs got oceanographically trapped and melted off rapidly. The sediment load sinking down to the seafloor formed a dropstone blanket particularly where the MdP Canyon had incised into the continental slope. Here, mass-flow processes, induced by local slope instability, and along-slope sediment resorting, due to the erosional effects of strong and persistent contouritic bottom currents, favored local enrichment in dropstones in the form of a loose, coarse sediment drape inside morphological depressions. The bottom current velocity would be locally strong enough to rework this sediment, leaving coarse rafted debris as a lag deposit.Fil: Bozzano, Graziella. Ministerio de Defensa. Armada Argentina. Servicio de Hidrografía Naval; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Cerredo, Maria Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; ArgentinaFil: Remesal, Marcela Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; ArgentinaFil: Steinmann, L.. Universitat Bremen; AlemaniaFil: Hanebuth, Till J.J.. Coastal Carolina University; Estados UnidosFil: Schwenk, T.. Universitat Bremen; AlemaniaFil: Baqués, Michele. Ministerio de Defensa. Armada Argentina. Servicio de Hidrografía Naval; Argentina. Ministerio de Defensa. Armada Argentina. Dirección Gral. de Investigación y Desarrollo de la Ara. Dirección de Investigación de la Armada; ArgentinaFil: Hebbeln, Dierk. Universitat Bremen; AlemaniaFil: Spoltore, Daniela Veronica. Ministerio de Defensa. Armada Argentina. Servicio de Hidrografía Naval; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; ArgentinaFil: Silvestri, Ornella. Ministerio de Defensa. Armada Argentina. Servicio de Hidrografía Naval; Argentina. Universidad de Buenos Aires; ArgentinaFil: Acevedo, Rogelio Daniel. Universidad Nacional de Tierra del Fuego, Antártida e Islas del Atlántico Sur. Instituto de Ciencias Polares, Ambientales y Recursos Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Spiess, V.. Universitat Bremen; AlemaniaFil: Violante, Roberto Antonio. Ministerio de Defensa. Armada Argentina. Servicio de Hidrografía Naval; ArgentinaFil: Kasten, Sabine. Universitat Bremen; Alemania. Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research; Alemani

Geflüchtete aus der Ukraine in Deutschland: Ergebnisse der ersten Welle der IAB-BiB/FReDA-BAMF-SOEP Befragung

Der gemeinsame Forschungsbericht des Instituts für Arbeitsmarkt- und Berufsforschung (IAB), des Bundesinstituts für Bevölkerungsforschung (BiB), des Forschungszentrums des Bundesamtes für Migration und Flüchtlinge (BAMF-FZ) und des Sozio-oekonomischen Panels (SOEP) am DIW Berlin stellt vertieft zentrale Befunde aus der gemeinsamen Studie "Geflüchtete aus der Ukraine in Deutschland" vor. Im Fokus der bundesweiten Studie stehen das Ankommen, die aktuellen Lebensumstände sowie Zukunftspläne der ukrainischen Geflüchteten in Deutschland. Die Analysen basieren auf rund 11.700 Interviews mit ukrainischen Männern und Frauen, die im Zeitraum vom 24. Februar bis zum 8. Juni 2022 nach Deutschland gekommen sind. Die Interviews wurden deutschlandweit auf Basis standardisierter Fragebögen online (CAWI) oder per Papierfragebogen (PAPI) im Zeitraum von August bis Oktober 2022 durchgeführt. Im Zuge der Stichprobenziehung wurden zunächst anhand des Ausländerzentralregisters (AZR) 100 Gemeinden mit einem hohen Anteil von ukrainischen Geflüchteten ausgewählt. Die ausgewählten Gemeinden wurden dann gebeten, Adressen dieser Zielpopulation zur Verfügung zu stellen. Durch Verwendung von Gewichten ist die Stichprobe repräsentativ für diese Grundgesamtheit. Die Studie ist als Längsschnittbefragung geplant, im Frühjahr 2023 wird eine zweite Befragungswelle durchgeführt. Erste zentrale Befunde aus der ersten Welle wurden bereits im Dezember 2022 im Rahmen einer Kurzanalyse veröffentlicht

Die Linsenluxation beim Hund: Eine retrospektive Studie von 134 Hunden (2000 – 2011)

In dieser retrospektiven Studie wurden alle zwischen 2000 und 2011 am Tierspital Zürich vorgestellten Hunde mit Linsenluxation (LL) erfasst. Insgesamt waren134 Hunde ein- oder beidseitig von einer Linsenluxation betroffen. Dies entspricht 0.41 % der Gesamtpopulation (32'523) der am Tierspital Zürich vorgestellten Hunde, und 3.02 % aller Hunde, die in der Abteilung für Ophthalmologie vorgestellt wurden. Die 134 Hunde gehörten 40 unterschiedlichen Rassen an. Beide Geschlechter waren gleichermassen betroffen. Eine primäre Linsenluxation wurde bei 64 % der Hunde diagnostiziert. Die häufigsten Ursachen für sekundäre Linsenluxationen waren Glaukom (58 %), Katarakt (19 %) und Trauma (17 %). Terrier, Chinesische Schopfhunde, Pinscher und Spitze sind signifikant häufiger von primären als von sekundären Linsenluxationen betroffen. Huskies, Basset Hounds, Bearded Collies, Cairn Terrier, Mischlinge, Bolonka Zwetna, Boston Terrier, Barzoi, Dobermann, Eurasier, Leonberger, Luzerner Niederlaufhunde sowie Weimaraner wiesen signifikant häufiger sekundäre Linsenluxationen auf. Hunde mit einer primären LL waren beim Auftreten der Erkrankung durchschnittlich 7.39 ± 3.02 Jahre alt und somit signifikant jünger als jene Hunde mit sekundärer LL (9.12 ± 3.38 Jahre). Primäre Linsenluxationen traten signifikant häufiger bilateral auf als sekundäre (85.5 % der primären LL waren bilateral, bei den sekundären LL nur 14.5 %)

Earthquake-induced methane migration through the gas hydrate stability zone in the subduction regime offshore Pakistan

Although gas hydrates often occur in seismically active regions, the role of earthquakes as triggers of hydrocarbon seepage through gas hydrate-bearing sediments has been only super�cially addressed. The Makran continental margin o�shore Pakistan hosts hydrocarbon-laden sediments and gas hydrates and is prone to vigorous seismicity. The area was visited in the frame of RV METEOR expedition M 74/3 in 2007 (Bohrmann et al. 2008). Here we present geochemical evidence for a substantial increase in upward gas �ux inducing methane emission into the water column and gas hydrate formation in the sediment, a phenomenon which occurred within a few decades of the strongest earthquake ever reported for the entire Arabian Sea. We propose a causal relation and present re�ection seismic data supporting our hypothesis that co-seismic ground shaking induced mechanical fracturing of gas hydrate-bearing sediments creating pathways for free gas to migrate from a shallow reservoir within the gas hydrate stability zone into the water column. Our �ndings lead to conclude that hydrocarbon seepage triggered by earthquakes might play a role for carbon budgets at other seismically active continental margins. The newly identi�ed process presented here can help interpret data from similar sites

Enzymatic elaboration of oxime-linked glycoconjugates in solution and on liposomes

Oxime formation is a convenient one-step method for ligating reducing sugars to surfaces, producing a mixture of closed ring α- and β-anomers along with open-chain (E)- and (Z)-isomers. Here we show that despite existing as a mixture of isomers, N-acetylglucosamine (GlcNAc) oximes can still be substrates for β(1,4)-galactosyltransferase (β4GalT1). β4GalT1 catalysed the galactosylation of GlcNAc oximes by a galactose donor (UDP-Gal) both in solution and in situ on the surface of liposomes, with conversions up to 60% in solution and ca. 15–20% at the liposome surface. It is proposed that the β-anomer is consumed preferentially but long reaction times allow this isomer to be replenished by equilibration from the remaining isomers. Adding further enzymes gave more complex oligosaccharides, with a combination of α-1,3-fucosyltransferase, β4GalT1 and the corresponding sugar donors providing Lewis X coated liposomes. However, sialylation using T. cruzi trans-sialidase and sialyllactose provided only very small amounts of sialyl Lewis X (sLe(x)) capped lipid. These observations show that combining oxime formation with enzymatic elaboration will be a useful method for the high-throughput surface modification of drug delivery vehicles, such as liposomes, with cell-targeting oligosaccharides

Direct Analysis of Biotransformations with Mass Spectrometry – DiBT-MS

Ambient ionization coupled to mass spectrometry has the advantages of minimal requirements for sample preparation prior to analysis which renders it suitable for high throughput screening. We present a protocol that permits the application of this method in routine biotechnology and chemical biology laboratories which are using engineered enzymes to produce target compounds from substrates. We show how DESI-MS can be used to directly analyse the activity of biotransformations from crude cell lysate which we term DiBT-MS, this method is 10-1000 times faster than LC-MS and uses far less solvent. This protocol demonstrates the impact of solvent spray composition on ionization efficiency of the target analyte, the benefits of a nylon membrane slide and the reusability of sample slides in multiple experiments.

Functional and protein chemical characterization of the N-terminal domain of the rat corticotropin-releasing factor receptor 1

Rat corticotropin-releasing factor receptor 1 (rCRFR1) was produced either in transfected HEK 293 cells as a complex glycosylated protein or in the presence of the mannosidase I inhibitor kifunensine as a high mannose glycosylated protein. The altered glycosylation did not influence the biological function of rCRFR1 as demonstrated by competitive binding of rat urocortin (rUcn) or human/rat corticotropin-releasing factor (h/rCRF) and agonist-induced cAMP accumulation. The low production rate of the N-terminal domain of rCRFR1 (rCRFR1-NT) by transfected HEK 293 cells, was increased by a factor of 100 in the presence of kifunensine. The product, rCRFR1-NT-Kif, bound rUcn specifically (KD = 27 nM) and astressin (KI = 60 nM). This affinity was 10-fold lower than the affinity of full length rCRFR1. However, it was sufficiently high for rCRFR1-NT-Kif to serve as a model for the N-terminal domain of rCRFR1. With protein fragmentation, Edman degradation, and mass spectrometric analysis, evidence was found for the signal peptide cleavage site C-terminally to Thr23 and three disulfide bridges between precursor residues 30 and 54, 44 and 87, and 68 and 102. Of all putative N-glycosylation sites in positions 32, 38, 45, 78, 90, and 98, all Asn residues except for Asn32 were glycosylated to a significant extent. No O-glycosylation was observed

Subduction zone earthquake as potential trigger of submarine hydrocarbon seepage offshore Pakistan

Seepage of methane-dominated hydrocarbons is heterogeneous in space and time, and trigger mechanisms of episodic seep events are not well constrained. It is generally found that free hydrocarbon gas entering the local gas hydrate stability field in marine sediments is sequestered in gas hydrates. In this manner, gas hydrates can act as a buffer for carbon transport from the sediment into the ocean. However, the efficiency of gas hydrate-bearing sediments for retaining hydrocarbons may be corrupted: Hypothesized mechanisms include critical gas/fluid pressures beneath gas hydrate-bearing sediments, implying that these are susceptible to mechanical failure and subsequent gas release. Although gas hydrates often occur in seismically active regions, e.g., subduction zones, the role of earthquakes as potential triggers of hydrocarbon transport through gas hydrate-bearing sediments has hardly been explored. Based on a recent publication (Fischer et al., 2013), we present geochemical and transport/reaction-modelling data suggesting a substantial increase in upward gas flux and hydrocarbon emission into the water column following a major earthquake that occurred near the study sites in 1945. Calculating the formation time of authigenic barite enrichments identified in two sediment cores obtained from an anticlinal structure called “Nascent Ridge”, we find they formed 38-91 years before sampling, which corresponds well to the time elapsed since the earthquake (62 years). Furthermore, applying a numerical model, we show that the local sulfate/methane transition zone shifted upward by several meters due to the increased methane flux and simulated sulfate profiles very closely match measured ones in a comparable time frame of 50-70 years. We thus propose a causal relation between the earthquake and the amplified gas flux and present reflection seismic data supporting our hypothesis that co-seismic ground shaking induced mechanical fracturing of gas hydrate-bearing sediments creating pathways for free gas to migrate from a shallow reservoir within the gas hydrate stability zone into the water column. Our results imply that free hydrocarbon gas trapped beneath a local gas hydrate seal was mobilized through earthquake-induced mechanical failure and in that way circumvented carbon sequestration within the sediment. These findings lead to conclude that hydrocarbon seepage triggered by earthquakes can play a role for carbon budgets at other seismically active continental margins. The newly identified process presented in our study is conceivable to help interpret data from similar sites

Pockmarks in the northern Congo Fan area, SW Africa: complex seafloor features shaped by fluid flow

Three pockmarks named "Hydrate Hole", "Black Hole", and "Worm Hole" were studied in the northern Congo Fan area at water depths around 3100 m. The cross-disciplinary investigations include seafloor observations by TV-sled, sampling by TV-guided grab and multicorer as well as gravity coring, in addition to hydroacoustic mapping by a swath system, a parametric sediment echosounder and a deep-towed sidescan sonar. The pockmarks are morphologically complex features consisting of one or more up to 1000 m wide and 10-15 m deep depressions revealed by swath-mapping. High reflection amplitudes in the sediment echosounder records indicate the presence of a 25-30 m thick shallow sediment section with gas hydrates, which have been recovered by gravity corer. Hydrates, chemosynthetic communities, and authigenic carbonates clearly indicate fluid flow from depths, which we propose to be mainly in the form of ascending gas bubbles rather than advection of methane-rich porewater. Evidence for seepage at the seafloor is confined to small areas within the seafloor depressions and was revealed by characteristic backscatter facies. Small meter-scale sized depressions signified as "pits" exist in or close to the pockmarks but seafloor observations did not reveal evidence for the presence of typical seep organisms or authigenic carbonates. Areas of intermediate back-scatter were inhabited by vesicomyid clams in soft sediments. High backscatter was associated with vestimentiferan tubeworms (Siboglinidae) and authigenic carbonates. We discuss the three different environments "pits", "vesicomyid clams", "vestimentifera/carbonate" in the light of differences in the geochemical setting. Pits are probably formed by escaping gas bubbles but seepage is too transient to sustain chemosynthetic life. Vesicomyid clams are present in sediments with gas hydrate deposits. However, the hydrates occur several meters below the surface indicating a lower flux compared to the vestimentifera/carbonate environment. In the latter environment, accumulated carbonates and clam shells indicate that fine grained particles have been eroded away. Gas hydrates were found in this environment at depths below about 50 cm suggesting the highest supply with methane compared to the other environments. (C) 2007 Elsevier B.V. All rights reserved