Process engineering and microbiological optimization of biofiltration systems in aquaculture plants

Topic: Process engineering and microbiological optimization of biofiltration systems in aquaculture plants 

Coordination: LimnoMar Dr. Burkard T. Watermann

Processing of subproject: Prof. Dr. Wolfgang Sand, B.Sc. Jürgen Schrötz 

Sponsorship: Deutsche Bundesstiftung Umwelt

Cooperation partners: LimnoMar Hamburg, GEA 2H Water Technologies GmbH, GMA Gesellschaft für Marine Aquakultur mbH, Kunststoff Spranger GmbH, Biozentrum Klein Flottbek Universität Hamburg AG Spieck

Project Phase 2: August 2008 to May 2010
Projectstart Phase 3: June 2010 to July 2012

The overfishing of the oceans is growing interest in aquaculture plants worldwide. In contrast to net cages, recirculating mariculture systems preserve the resources, as the water is recycled with a biological purification. So far, there have been only a few studies of microbiological analyses of the biofiltration process in aquaculture plants, so that the development requirement in this field is very high.

As part of the project-phase 2, the group of Prof. Sand investigated the initial attachment of marine nitrifyers on different composition of plastic foils.
The BioMAT™ Workstation from JPK Instruments (atomic force microscope (AFM) coupled with epifluorescence microscope (EFM)) was used for the visualization of attachment tests. 

In further experiments in project-phase 3 it is intended to:

- Analyze the responsible extracellular polymeric substances for the biofilm formation of the nitrifyers.
- Bioreactor Design with a volume of 135 Liter (parameter controlling with online-monitoring) for incubated therein filling bodies of different types with marine nitrifyers.
- Surface analysis was achieved with chemically modified cantilever with the goal, to determine the polar charges of the surface.

Biogenic sulfuric acid corrosion of different materials

Topic: Biogenic sulfuric acid corrosion of different materials

Project in cooperation with Fraunhofer Institute for Environmental, Safety and Energy Technology UMSICHT

Responsible: Nanni Noël (MSc), Prof. Dr. W. Sand

Contact person: Fraunhofer UMSICHT: Dr. H. Wack

Biogenic sulfuric acid corrosion is a chemical attack to surfaces of different materials such as concrete, iron and polymers. It is caused by sulfuric acid producing bacteria from the genus Thiobacillus. It mainly occurres in waste water systems, where sulfur compounds are degraded by microorganisms. Gaseous sulfur compounds are released and accumulate in the head space. Chemical oxidation of H2S to elemental sulfur and the following biological oxidation via thiosulfate and other polythionates cause a decrease of pH (<7). The reduced sulfur compounds are oxidized to sulfuric acid, resulting in suitable conditions for growths of Thiobacilli (T. neapolitanus, T. intermedia) which further decrease the pH. Below pH 5.5 A. thiooxidans colonize the surface Between pH 2.0-3.0 this organism will find optimal growth conditions. Result is a successive colonization of surfaces by different Thiobacilli. Sulfuric acid is produced as a metabolite of these organisms causing an attack on different materials.
In cooperation with Fraunhofer Institute for Environmental, Safety and Energy Technology UMSICHT in Oberhausen a pilot plant was developed and the effect of biogenic sulfuric acid corrosion on different materials is tested. The pilot plant is located at the Fraunhofer Institute, microbiological analyses are performed in the lab of the Aquatic Biotechnology, Universität Duisburg. All samples are investigated using analytical as well as microbiological techniques. Microbiological analysis include different organisms like acidophilic and neutrophilic iron- and sulfur oxidizers, sulfate reducing bacteria, nitrite oxidizers, fungi, chemoorganotrophic bacteria and more.
Using this pilot plant the resistance against biogenic sulfuric acid corrosion of different materials can be investigated and optimized subsquently.

Molecular characterization of biofilm formation processes by bioleaching microorganisms

Funded by Promotion of Young Researchers Program (UDE) for 2010.

Responsible: Dr Mario Vera V.

Biomining is an industrial process in which leaching microorganisms are used for recovering valuable metals, such as copper or gold, from sulfidic ores. Molecular studies on biofilms formed by these bacteria in minerals such as pyrite (FeS2) are very difficult mainly due to their low growth rates, the presence of ferric iron, sulfur and exopolymeric substances (EPS), which drastically interfere with conventional DNA, RNA and protein extraction methods. Still many biofilm related functions, such as EPS biosynthesis, chemotaxis, competence, motility, protein and expolysaccharides secretion pathways still remain unknown in leaching bacteria. The knowledge about these pathways would allow an improvement of these processes resulting in widespread technological applications (Acid Mine Drainage abatement, enhancement of bioleaching by use of low-grade ores and biocorrosion reduction).

By using molecular tools we study the model organism Acidithiobacillus ferrooxidans and its biofilm formation process in minerals for i) the transcriptional differences between planktonic and sessile cells at different stages of At. ferrooxidans biofilm formation on pyrite. (In collaboration with Dr. Violaine Bonnefoy, CNRS, France). ii) Proteomics; proteins obtained from biofilm and planktonic cells are purified and analyzed by high resolution mass spectrometry in order to reveal changes in the proteome between both bacterial subpopulations (in collaboration with Dr. Ansgar Poetsch, Ruhr University, Bochum).

Our research also includes testing of Quorum Sensing molecules and analogs in order to identify super activators and inhibitors of the At. ferrooxidans biofilm formation process on sulphur and mineral surfaces (In collaboration with Dr. Nicolas Guiliani, University of Chile).

Novel corrosion protection by application of microbial extracellular polymeric substances (biofilm-induced corrosion inhibition)

Topic: Biocorrosion (MIC – microbially influenced corrosion)

Joint project, funded by the German Federation of Industrial Research Associations AiF Otto von Guericke. Period: January 2005 to October 2007, October 2007 to October 2010 (continuation). Co-operation partner: DECHEMA e.V., Karl-Winnacker-Institut, Frankfurt (Main), Germany. 
Persons in charge (sub-project): Prof. Dr. Wolfgang Sand, Dr. Tilman Gehrke, M.Sc. Andrzej Kuklinski.

Aim of the project: Evaluation of extracellular polymeric substances (EPS) from various organisms for the mitigation of microbially influenced corrosion (MIC) by sulfate-reducing bacteria. 

Background: Several biofilms have been described to influence MIC directly or indirectly. Most of the protective properties are ascribed to the EPS. Additionally, EPS have been demonstrated to prevent microbial adhesion and thus formation of detrimental biofilms. Few to none research was conducted until now to evaluate the potential of direct application of EPS. As conventional countermeasures are expensive, ineffective and/or environmentally harmful, application of EPS represents a promising new approach.

Adhesion- and distribution-mechanisms of iron- and sulfur- oxidizing microorganisms on metal-sulfides and inhibition strategies

Coordination: Dr. M. Strzodka, Dr. P. Jolas, I. Arnold,

Responsible of subproject: Bianca Florian, MSc
Financing institution: GMB, MIBRAG, Vattenfall

Cooperation partners: Hochschule Lausitz (FH) University of Applied Science

Workinggroup: Prof. Dr. K.-P. Stahmann; 
Bearbeitung des Teilprojektes/ processing of subproject: H.-M. Siebert, MSc

Running time: 2008 bis 2010

Bioleaching is the dissolution of metal sulfides, such as pyrite and chalcopyrite, by microbial oxidation processes. Leaching processes are used for the winning of metals such as Au, Cu, Zn, or Ni. On the other hand bioleaching causes acid mine drainage (AMD)/ acid rock drainage (ARD) as a natural process, where ever metal sulfides are exposed to the environment e.g. in brown-coal mining areas. It has been found that attachment of leaching bacteria to the mineral surface enhances the processes of metal sulfide dissolution. Therefore, in this study we quantify and visualize the initial colonization and biofilm formation of leaching microorganisms on sulfide minerals. Sessile and planktonic cells and their biofilms are visualized by epifluorescence microscopy (EFM) using DAPI, SytoTM9, FISH, lectin- and calcofluor- staining. Additionally, atomic force microscopy (AFM) is used for investigations on cell morphology, spatial arrangement of cells on pyrite and mineral surface topography. 

The ensuing work is concerned with inhibition measures in order to reduce AMD/ARD as much as possible. Leaching-inhibition with several detergents is arranged in column-experiments, filled with material from brown-coal areas, where AMD/ARD takes place. Microcalorimetry is used to determine metabolic activity of leaching bacteria.

Development of bioreagents for the flotation of metal sulfides

Topic: Bioflotation

Cooperative project, supported by the German Research Foundation (DFG), April 2000 to July 2002; renewed: December 2002 to April 2005

In addition to the University of Duisburg-Essen, other partners are: Institut für Aufbereitung und Deponietechnik der Technischen Universität Clausthal

Coordinator Institut für Aufbereitung und Deponietechnik der Technischen Universität Clausthal, Clausthal-Zellerfeld; Subproject processing: Prof. Dr. Wolfgang Sand, Dipl.-Biol. Kerstin Harneit

Biotechnology for Metal bearing materials in Europe (BioMinE)

More: Project website

Topic: Bioleaching, Bioflotation

Cooperative project, supported by the European Union (November 2004 to October 2008)

In addition to the University of Duisburg-Essen, other partners are: BRGM, Hellenic Copper Mines, Tampere University of Technology, Technische Universität Berlin, IGME, National Technical University of Athens, Bioclear B.V., Paques B.V., Wageningen University, Instityt Metali Niezelaznych, Instituto National De Engeharia, De Beers Consolidated Mines Ltd,MINTEK, University of Cape Town, University of Stellenbosch, Universidad Autonoma de Madrid, Luleå University of Technology, MEAB Metallextraktion AB, Umeå University,CellFacts Instruments Ltd, Greenwich Resources plc, Imperial College of Science & Technology, Rio Tinto Technical Services Ltd, University of Wales, University of Warwick, Tecnicas Reunidas S.A., Outokumpu Research Oy, Umicore, Skeria, CNRS, Universität Stuttgart, PE Europe GmbH, The Institute for Nonferrous and Rare Metals sowie MiltonRoy Mixing

Coordinator: Bureau de Recherches Geologiques et Minieres (BRGM), Orleans; Subproject processing: Prof. Dr. Wolfgang Sand, Dr. Tilman Gehrke, Dr. Thore Rohwerder

Development of swellable rubber sealings basing on elastomer-fiber-blends

Topic: Biofilms

Cooperative project, supported by the Bundesministerium für Wirtschaft und Technologie (BMWi) (April 2002 to April 2005)

In addition to the University of Duisburg-Essen, other partners are: Forschungsinstitut für Tief- und Rohrleitungsbau Weimar e.V., das Thüringische Institut für Textil- und Kunststoff-Forschung e.V., GKT Gummi- und Kunststofftechnik Fürstenwalde GmbH, das Ingenieurbüro für Bauwerkserhaltung Weimar GmbH and Ostthüringische Materialprüfungsgesellschaft für Textil- und Kunststoffe mbH Rudolstadt

Coordinator: Forschungsinstitut für Tief- und Rohrleitungsbau e.V., Weimar; Subproject processing: Prof. Dr. Wolfgang Sand, Dipl.-Biol. Florian Brill