Axel Schippers

Bundesanstalt für Geowissenschaften und Rohstoffe | BGR · Geomicrobiology

While biomining is currently restricted to reduced (sulfide) ores, many commercially valuable metals can be found in significant concentrations in oxidised ores. These comprise laterites, polymetallic marine nodules, and ores from oxidation of sulfide deposits. Currently, these oxide ores are processed using pyro- or hydrometallurgical techniques,...

A novel thermoacidophilic archeaon, strain J1 T (=DSM 112778 T ,=JCM 34702 T), was isolated from a hot pool in a volcanic area of Java, Indonesia. Cells of the strain were irregular, motile cocci of 1.0-1.2 µm diameter. Aerobic, organoheterotrophic growth with casamino acids was observed at an optimum temperature of 70 °C in a range of 55-78 °C and...

Bioleaching of metal sulfides is performed by diverse microorganisms. The dissolution of metal sulfides occurs via two chemical pathways, either the thiosulfate or the polysulfide pathway. These are determined by the metal sulfides’ mineralogy and their acid solubility. The microbial cell enables metal sulfide dissolution via oxidation of iron(II)...

This review provides an update to the last mini-review with the same title pertaining to recent developments in bioleaching and biooxidation published in 2013 (Brierley and Brierley). In the intervening almost 10 years, microbial processes for sulfide minerals have seen increased acceptance and ongoing but also declining commercial application in c...

Granulated blast furnace slag (GGBFS) is a potential resource of rare earth elements (REEs), and due to the complex mineralogy, extraction by conventional hydrometallurgical process makes it an acid-consuming method. Bioleaching is thus investigated using a chemo-organotrophic bacterium, Gluconobacter oxydans (DSMZ 46616) for REE extraction from GG...

Citation: Stanković, S.; Kamberović, Ž.; Friedrich, B.; Stopić, S.R.; Sokić, M.; Marković, B.; Schippers, A. Abstract: The automotive industry is in the process of transformation from the traditional production of vehicles with engines powered by the combustion of fossil fuels to vehicles powered by electric energy. This revolutionary transformatio...

Metals from low-grade sulfide ores, electronic waste and mine tailings can be recovered using biohydrometallurgy. In this study, acidophilic microbial consortia of mesophiles and moderate thermophiles were applied in shake flasks as well as in stirred tank reactors (STR) to bioleach cobalt and copper from mine tailings in Chile. The mine tailings n...

A novel deltaproteobacterial, mesophilic, hydrogen-oxidizing, and sulfate-reducing bacterium (strain KaireiS1) was highly enriched from an inactive chimney located in the active zone of the Kairei hydrothermal vent field (Central Indian Ridge) in the Indian Ocean. Based on 16S rRNA gene analyses, strain KaireiS1 is the currently only cultured repre...

Red mud (RM) as waste of industrial aluminum production is piling up in huge ponds. RM could be a cost-effective adsorbent for heavy metals, but adsorption is vulnerable to pH changes, metal ions speciation and the occurrence of iron bearing minerals. In this study, the precipitation and elemental speciation transformation relevant to arsenic fate...

A mixotrophic and acidophilic bacterial strain BGR 140 T was isolated from mine tailings in the Harz Mountains near Goslar, Germany. Cells of BGR 140 T were Gram-stain-positive, endospore-forming, motile and rod-shaped. BGR 140 T grew aerobically at 25–55 °C (optimum 45 °C) and at pH 1.5–5.0 (optimum pH 3.0). The results of analysis of the 16S rRNA...

The effect of the galvanic interaction between anodic chalcopyrite and cathodic pyrite was investigated by long-term electrochemical measurements of the galvanic coupling current and verified by chemical leaching and bioleaching. For the first time galvanic corrosion measurements (in the absence and in the presence of microorganisms) over days are...

The aim was to study bioleaching of rare earth elements from red mud by a chemoorganotrophic microorganism, and to investigate the microbe-mineral interactions. Red mud is a promising resource for scandium, whose concentration was 92 and 54 mg/kg in two samples from Germany and India, respectively; however, both showed appreciably high concentratio...

Heavy-metal mines might be a tough environment to grow up in, but many microbes call them home, including viruses. A recent look at core samples from a lead and zinc mine in China revealed how viruses fit into this extreme ecosystem. Environmental factors like acidity appeared to play a big role in shaping viral communities. High acidity tends to m...

Biohydrometallurgy recovers metals based on bioprocess engineering. This includes bioleaching, whereby metals are extracted by microbially catalyzed dissolution of ores in a strong acidic environment. These are favorable conditions for applied electroanalysis and electrochemical engineering. Applicable for process control and improvement are either...

The potential for the mobilization of Fe from secondary phases within subsurface basaltic rocks of the Hawaii Scientific Drilling Project Phase2 (HSDP2) drill core was investigated to elucidate the possible contribution of volcanic islands to the Fe budget of nearby ocean surface waters. Rock specific parameters governing Fe mobilization, such as F...

A microbial consortium of mesophilic and acidophilic bacteria and archaea was applied in shake flasks as well as in 2 L stirred tank reactors (STR) to bioleach cobalt, copper, and other valuable metals from sulfidic mine tailings (Rammelsberg polymetallic massive sulfide deposit, Harz mountains, Germany). After succession from low to high pulp dens...

Acidic solutions from metal bioleaching processes usually contain mixtures of metals in different concentrations which need to be separated and concentrated in downstream processing. Aim of this study was to explore and compare biosorption of rare earth elements (REE) by different microorganisms in acidic solutions. Biosorption of REE by bacteria a...

Platinum-group elements (PGE) are relevant for many high technology applications, prompting the search for potential alternative resources and environmentally friendly processing technologies. The largest deposit of PGE worldwide is the Bushveld Complex in South Africa. The pristine sulfide-bearing ore is mined using conventional metallurgical meth...

Background: Recent studies have significantly expanded our knowledge of viral diversity and functions in the environment. Exploring the ecological relationships between viruses, hosts, and the environment is a crucial first step towards a deeper understanding of the complex and dynamic interplays among them. Results: Here, we obtained extensive...

The iron-bentonite interface will be important with respect to the long-term performance of high-level radioactive waste (HLW) disposal sites. Magnetite and Fe-silicates form at this interface due to anoxic corrosion. The corrosion mechanism, however, is still under debate. In the present study two bentonites differing with respect to their content...

Acidophilic microorganisms can thrive in both natural and man-made environments. Natural acidic environments comprise hydrothermal sites on land or in the deep sea, cave systems, acid sulfate soils and acidic fens, as well as naturally exposed ore deposits (gossans). Man-made acidic environments are mostly mine sites including mine waste dumps and...

Elemental release from basaltic glasses at far from equilibrium conditions was investigated as a function of the Fe redox state (Fe(II)/Fetot = 0.35 and 0.80) and thermal history (quenched ↔ annealed). A flow-through column setup was used to ensure disequilibrium of basaltic glass and solution during the entire runtime. Percolation experiments were...

Background: Recent studies have significantly expanded our knowledge of viral diversity and functions in the environment. Exploring the ecological relationships between viruses, hosts and the environment is a crucial first step towards a deeper understanding of the complex and dynamic interplays among them. Results: Here, we obtained extensive 16S...

Microbial metabolisms in sediments play a pivotal role in marine element cycling. In hydrothermal sediments chemosynthetic microorganisms likely prevail, while in non-hydrothermally impacted sediment regimes microorganisms associated with organic matter decomposition are primarily recognized. To test how these microorganisms are distributed along t...

Formation of mineral-organic associations is a key process in the global carbon cycle. Recent concepts propose litter quality-controlled microbial assimilation and direct sorption processes as main factors in transferring carbon from plant litter into mineral-organic associations. We explored the pathways of the formation of mineral-associated orga...

Biooxidation of reduced inorganic sulfur compounds (RISCs) by thermoacidophiles is of particular interest for the biomining industry and for environmental issues, e.g., formation of acid mine drainage (AMD). Up to now, interfacial interactions of acidophiles with elemental sulfur as well as the mechanisms of sulfur oxidation by acidophiles, especia...

Chalcopyrite is the most abundant but also the most recalcitrant copper sulfide mineral in leaching processes. The reasons for its refractory character are passivation and/or its semi-conductive properties. In our study chalcopyrite was hydrometallurgically processed via chemical leaching, electrochemical leaching, bioleaching and electrobioleachin...

Bioleaching experiments with a mixed Acidithiobacillus-culture were carried out in shake flasks as well as in column percolators with crushed and sieved sphalerite-rich ore from a former mine in the German Harz Mountains. Efficient sphalerite dissolution in the bioleaching assays was observed in contrast to the chemical leaching experiments. The re...

Soil microorganisms are key players of the nitrogen cycle and relevant for soil development. While the community structure of nitrogen-cycling microorganisms during initial soil development is already well investigated, knowledge about the patterns during long-term ecosystem development is limited. In this study, nitrogen functional genes of ammoni...

The purpose of this study was to compare the efficacy of galactose and high initial ferrous iron concentrations as inducers for extracellular polymeric substances (EPS) production in planktonic cells of Leptospirillum ferrooxidans and to study cell attachment to a mineral surface in comparison to cells not exposed to such substances. Leptospirillum...

To assess the risk that mining of seafloor massive sulfides (SMS) from extinct hydrothermal vent environments has for changing the ecosystem irreversibly, we sampled SMS analogous habitats from the Kairei and the Pelagia vent fields along the Indian Ridge. In total 19.8 million 16S rRNA tags from 14 different sites were analyzed and the microbial c...

The interaction of a single bacterial species (Burkholderia fungorum) with basaltic rocks from the ICDP HSDP2 drill core and synthetic basaltic glasses was investigated in batch laboratory experiments to better understand the role of microbial activity on rock alteration and Fe mobilization. Incubation experiments were performed with drill core bas...

Pregnant leach solutions (PLS) resulting from (bio)leaching of copper ores are characterized by low pH, high concentrations of Fe (III), Cu, Zn and often significant amounts of Ni and Co. In order to make the metals available for further processing they require selective recovery form the acidic, multi-metal solution. Commonly, copper and other bas...

Acidophiles, including a mixed mesophilic, iron-oxidizing culture (FIGB) and a thermophilic enrichment culture (TK65) from a black shale and sandstone copper ore (Kupferschiefer), were used to evaluate microbial ferric iron reduction coupled to oxidation of reduced inorganic sulfur compounds (RISCs) at elevated pressure to simulate potential biogeo...

Primary copper sulfides, such as chalcopyrite, represent the most important copper resource and are currently mainly exploited by pyrometallurgy. Bioleaching is considered as environmental-friendly and economic alternative, and the technical feasibility of stirred tank reactor (STR) bioleaching of copper ore concentrates using acidophilic, iron- /s...

Sulfidic mine tailings have a high potential for contamination of the environment by triggering acid mine drainage. Hence, it is crucial to understand metal mobilization processes and to develop monitoring tools. Metal isotope fingerprinting as a potential monitoring tool for metal sulfide oxidation processes was in the focus of this study by using...

The extraction of copper from black shales associated with fine-grained and complex base metal ore mineralization traditionally using pyrometallurgy becomes increasingly uneconomic, because one of the most significant cost factors is the high energy consumption. Thus, energy-saving alternative mineral processing methods are to be considered to impr...

Iron (Fe) oxyhydroxides are important constituents of the soil mineral phase known to stabilize organic matter (OM) under oxic conditions. In an anoxic milieu, however, these Fe-organic associations are exposed to microbial reduction, releasing OM into soil solution. At present, only few studies have addressed the influence of adsorbed natural OM (...

Biohydrometallurgy comprises the recovery of metals by biologically catalyzed metal dissolution from solids in an aqueous solution. The application of this kind of bioprocessing is described as “biomining,” referring to either bioleaching or biooxidation of sulfide metal ores. Acidophilic iron- and sulfur-oxidizing microorganisms are the key to suc...

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 th...

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 abundan...

In this study, two black shale copper ores from different Mid-European Kupferschiefer-type deposits and their flotation concentrates were used for bioleaching tests. All samples were subjected to stirred tank bioleaching using an acidophilic, moderately thermophilic microbial consortium. The distribution of sulfides and gangue minerals in the ores,...

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...

Kupferschiefer-type ore represents an important source for base metals and several studies concerning the bioleaching of black shale ores and Cu concentrates have been carried out with focus on various microbial communities and processing parameters. However, the incomplete dissolution of chalcopyrite remains a key issue for copper ore bioleaching...

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) a...

Pregnant leach solutions (PLS) resulting from bioleaching of copper concentrate from Kupferschiefer are characterized by low pH and high concentrations of Fe, Cu, Zn as well as significant amounts of Ni and Co. In order to recover the valuable metals for further processing, chemical methods and a novel biological-induced technique that promotes sel...

In a mine owned by the company Orenas S.A. (Equador), a biooxidation process for gold recovery has been developed. Refractory gold ore was crushed, milled and 500 ton of flotation concentrate was agglomerated by coating a support rock. This was piled up on a liner and the biooxidation process in the heap of 35x25x6 m³ was run for approximately 150...

Primary copper sulfides are recalcitrant to bioleaching, probably due to semi-conductivity or passivation effects which result in slow dissolution kinetics. The mineral dissolution strongly depends on redox reactions and, consequently, electrochemical techniques are recommendable for analyzing and processing of redox-active minerals. For this reaso...

The rare-earth elements (REE) comprise a group of critical chemical elements with special electronic, magnetic, optical and catalytic properties that are crucial for a range of EU high-tech industries, including the automotive, wind-energy, electronics, and metallurgy sectors. Conventional REE mining from monazite and bastnaesite minerals in these...

“SEEsand” stands for REE production out of running off-shore aggregate extraction. The challenge is to separate the REE bearing Zircon-fraction and to dissolve the REE by means of hydrochemical and biochemical leaching. “SEEsand” unites an interdisciplinary team composed of geological authorities (1,7), industry (2,4,5), academia (3), and a triple...

Along a long-term ecosystem development gradient, soil nutrient contents and mineralogical properties change, therefore probably altering soil microbial communities. However, knowledge about the dynamics of soil microbial communities during long-term ecosystem development including progressive and retrogressive stages is limited, especially in mine...

Two common quantification methods for subseafloor microorganisms are catalyzed reporter deposition fluorescence in situ hybridization (CARD-FISH) and quantitative PCR (qPCR). Using these methods, we quantified Bacteria and Archaea in Baltic Sea basin sediments (IODP Exp. 347) down to 90 mbsf, testing the following hypotheses in an inter-laboratory...

Monitoring of the microbial community in bioleaching processes is essential in order to control process parameters and enhance the leaching efficiency. Suitable methods are, however, limited as they are usually not adapted to bioleaching samples and often no taxon-specific assays are available in the literature for these types of consortia. Therefo...

de Spezialisierte säureliebende Bakterien und Archaeen sind in der Lage Wertmetalle wie Kupfer, Gold, Kobalt, Nickel, Zink und Uran aus sulfidischen Erzen zu laugen. Dieser Prozess ist als Biolaugung bekannt und dessen Anwendung in der Bergbauindustrie als Biomining. Laborstudien haben auch die Biolaugung oxidischer Erze wie Laterite sowie von Berg...