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Extracellular polymeric substances involved in adhesion and biofilm formation by Sulfobacillus thermosulfidooxidans
Bioleaching is the mobilization of metal cations from insoluble ores by microorganisms. Bacteria first attach to minerals and then form biofilms, which can initiate and enhance bioleaching. Extracellular polymeric substances (EPS) play a crucial role during the whole process. Bacterial adhesion and biofilm formation are key steps to prevent environmental problems called acid mine drainage or to improve leaching efficiency in industry. Thus, profound investigations of EPS involved in bacterial adhesion and biofilm formation are crucial in order to guide the leaching process in one or the other direction. The Gram-positive bacterium Sulfobacillus thermosulfidooxidans DSM 9293T was chosen as the research object. The bacterium cannot form biofilms on pyrite. However, regularly exchanging exhausted medium with fresh medium leads to a continuous biofilm development on pyrite by S. thermosulfidooxidans. By this way multiply layered biofilms were observed on pyrite slices, while only monolayered biofilms were visible on pyrite grains. Meanwhile biofilm formation by S. thermosulfidooxidans on pyrite could also be observed just in the presence of Leptospirillum ferriphilum. Under biofilm favouring conditions the attachment and biofilm formation by S. thermosulfidooxidans were followed during pyrite leaching. The results indicate that a slimy and soft EPS matrix heterogeneously accumulated on the mineral surface inducing further bacterial adhesion and forming a robust biofilm. After attaching to the pyrite surface the cells started to change the composition of their EPS. Huge amounts of humic substances were detected in the biofilm EPS. A new technique based on an atomic force microscope (AFM) equipped with a pyrite-/chalcopyrite-modified cantilever instead of the use of silicon nitrides types was prove to be useful for quantifying the real interaction forces between planktonic cells or biofilms and the substrata. The force measurements were achieved under the natural living conditions of the bacteria without any artefact ...
Extracellular polymeric substances involved in adhesion and biofilm formation by Sulfobacillus thermosulfidooxidans
Bioleaching is the mobilization of metal cations from insoluble ores by microorganisms. Bacteria first attach to minerals and then form biofilms, which can initiate and enhance bioleaching. Extracellular polymeric substances (EPS) play a crucial role during the whole process. Bacterial adhesion and biofilm formation are key steps to prevent environmental problems called acid mine drainage or to improve leaching efficiency in industry. Thus, profound investigations of EPS involved in bacterial adhesion and biofilm formation are crucial in order to guide the leaching process in one or the other direction. The Gram-positive bacterium Sulfobacillus thermosulfidooxidans DSM 9293T was chosen as the research object. The bacterium cannot form biofilms on pyrite. However, regularly exchanging exhausted medium with fresh medium leads to a continuous biofilm development on pyrite by S. thermosulfidooxidans. By this way multiply layered biofilms were observed on pyrite slices, while only monolayered biofilms were visible on pyrite grains. Meanwhile biofilm formation by S. thermosulfidooxidans on pyrite could also be observed just in the presence of Leptospirillum ferriphilum. Under biofilm favouring conditions the attachment and biofilm formation by S. thermosulfidooxidans were followed during pyrite leaching. The results indicate that a slimy and soft EPS matrix heterogeneously accumulated on the mineral surface inducing further bacterial adhesion and forming a robust biofilm. After attaching to the pyrite surface the cells started to change the composition of their EPS. Huge amounts of humic substances were detected in the biofilm EPS. A new technique based on an atomic force microscope (AFM) equipped with a pyrite-/chalcopyrite-modified cantilever instead of the use of silicon nitrides types was prove to be useful for quantifying the real interaction forces between planktonic cells or biofilms and the substrata. The force measurements were achieved under the natural living conditions of the bacteria without any artefact ...
Extracellular polymeric substances involved in adhesion and biofilm formation by Sulfobacillus thermosulfidooxidans
Li, Qian (Autor:in) / Sand, Wolfgang
03.11.2017
Hochschulschrift
Elektronische Ressource
Englisch
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