scholarly journals Importance of Extracellular Polymeric Substances from Thiobacillus ferrooxidans for Bioleaching

1998 ◽  
Vol 64 (7) ◽  
pp. 2743-2747 ◽  
Author(s):  
Tilman Gehrke ◽  
Judit Telegdi ◽  
Dominique Thierry ◽  
Wolfgang Sand
Keyword(s):  
Extracellular Polymeric Substances ◽  
Thiobacillus Ferrooxidans ◽  
Pyrite Surface ◽  
Hydrophobic Properties ◽  
Primary Attachment ◽  
Leaching Bacteria

ABSTRACT Leaching bacteria such as Thiobacillus ferrooxidansattach to pyrite or sulfur by means of extracellular polymeric substances (EPS) (lipopolysaccharides). The primary attachment to pyrite at pH 2 is mediated by exopolymer-complexed iron(III) ions in an electrochemical interaction with the negatively charged pyrite surface. EPS from sulfur cells possess increased hydrophobic properties and do not attach to pyrite, indicating adaptability to the substrate or substratum.

The EPS of Acidithiobacillus ferrooxidans - a model for structure-function relationships of attached bacteria and their physiology

2001 ◽  
Vol 43 (6) ◽  
pp. 159-167 ◽  
Author(s):  
T. Gehrke ◽  
R. Hallmann ◽  
K. Kinzler ◽  
W. Sand
Keyword(s):  
Chemical Composition ◽  
Electrostatic Interaction ◽  
Acidithiobacillus Ferrooxidans ◽  
Extracellular Polymeric Substances ◽  
Pyrite Oxidation ◽  
Pyrite Surface ◽  
Hydrophobic Properties ◽  
Attached Bacteria ◽  
Primary Attachment ◽  
Leaching Bacteria

To dissolve pyrite or sulphur, leaching bacteria like Acidithiobacillus ferrooxidans attach to these substrata by extracellular polymeric substances (specifically, lipopolysaccharides). The primary attachment to pyrite at pH 2 is mediated by exopolymer-complexed iron(III) ions in an electrostatic interaction with the negatively charged pyrite surface. Cells grown on sulphur exhibit a different composition of the extracellular lipopolysaccharides, namely with increased hydrophobic properties, and do not attach to pyrite. Thus, the cells adapt the chemical composition of their exopolymers to the substrate/substratum. It is concluded that the mechanism of bacterial pyrite oxidation is basically indirect. The actual corrosive agents are iron(III) ions. Preliminary data indicate that active strains complex more iron(III) ions in their EPS than less active ones. Obviously, the exopolymeric layer comprises a reaction space for the regeneration of these ions by the activity of the iron oxidising bacteria.

scholarly journals Novel Combination of Atomic Force Microscopy and Epifluorescence Microscopy for Visualization of Leaching Bacteria on Pyrite

2007 ◽  
Vol 74 (2) ◽  
pp. 410-415 ◽  
Author(s):  
Stefanie Mangold ◽  
Kerstin Harneit ◽  
Thore Rohwerder ◽  
Günter Claus ◽  
Wolfgang Sand
Keyword(s):  
Atomic Force Microscopy ◽  
Extracellular Polymeric Substances ◽  
Metal Sulfide ◽  
Epifluorescence Microscopy ◽  
Bacterial Cells ◽  
Cell Integrity ◽  
Force Microscopy ◽  
Topographic Features ◽  
Atomic Force ◽  
Leaching Bacteria

ABSTRACT Bioleaching of metal sulfides is an interfacial process comprising the interactions of attached bacterial cells and bacterial extracellular polymeric substances with the surface of a mineral sulfide. Such processes and the associated biofilms can be investigated at high spatial resolution using atomic force microscopy (AFM). Therefore, we visualized biofilms of the meso-acidophilic leaching bacterium Acidithiobacillus ferrooxidans strain A2 on the metal sulfide pyrite with a newly developed combination of AFM with epifluorescence microscopy (EFM). This novel system allowed the imaging of the same sample location with both instruments. The pyrite sample, as fixed on a shuttle stage, was transferred between AFM and EFM devices. By staining the bacterial DNA with a specific fluorescence dye, bacterial cells were labeled and could easily be distinguished from other topographic features occurring in the AFM image. AFM scanning in liquid caused deformation and detachment of cells, but scanning in air had no effect on cell integrity. In summary, we successfully demonstrate that the new microscopic system was applicable for visualizing bioleaching samples. Moreover, the combination of AFM and EFM in general seems to be a powerful tool for investigations of biofilms on opaque materials and will help to advance our knowledge of biological interfacial processes. In principle, the shuttle stage can be transferred to additional instruments, and combinations of AFM and EFM with other surface-analyzing devices can be proposed.

Distribution and hydrophobic properties of Extracellular Polymeric Substances in biofilms in relation towards cohesion

2013 ◽  
Vol 165 (2) ◽  
pp. 85-92 ◽  
Author(s):  
M. Ras ◽  
D. Lefebvre ◽  
N. Derlon ◽  
J. Hamelin ◽  
N. Bernet ◽  
...  
Keyword(s):  
Extracellular Polymeric Substances ◽  
Hydrophobic Properties

Attachment Behavior of Leaching Bacteria to Metal Sulfides Elucidated by Combined Atomic Force and Epifluorescence Microscopy

2009 ◽  
Vol 71-73 ◽  
pp. 337-340 ◽  
Author(s):  
Bianca M. Florian ◽  
Nanni Noël ◽  
Soeren Bellenberg ◽  
J. Huergo ◽  
Thore Rohwerder ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Extracellular Polymeric Substances ◽  
Spatial Arrangement ◽  
Epifluorescence Microscopy ◽  
Metal Sulfides ◽  
Mineral Surface ◽  
Planktonic Cells ◽  
Force Microscopy ◽  
Atomic Force ◽  
Leaching Bacteria

The aim of the study was to quantify and to visualize colonization of metal sulfides by pure and mixed cultures. Strains of the genera Acidithiobacillus and Leptospirillum were tested. Sessile and planktonic cells were visualized by fluorescence microscopy using 4',6-diamidino-2-phenylindole (DAPI) and FISH. Additionally, atomic force microscopy was used for the investigations on cell morphology, spatial arrangement of cells on metal sulfides and mineral surface topography. It was shown that the morphology of sessile cells was totally different as compared with planktonic ones. Interactions of different species resulted in increased production of extracellular polymeric substances (EPS) or caused negligible-attaching bacteria to be incorporated into a biofilm by the good attaching ones. Consequently, biofilm formation was furthered.

Pyrite Surface after Thiobacillus ferrooxidans Leaching at 30°C

2010 ◽  
Vol 80 (3) ◽  
pp. 451-455 ◽  
Author(s):  
LU Jianjun ◽  
LU Xiancai ◽  
WANG Rucheng ◽  
LI Juan ◽  
ZHU Changjian ◽  
...  
Keyword(s):  
Thiobacillus Ferrooxidans ◽  
Pyrite Surface

Scanning Electron Microscope Study of Bacteria on Mineral Surfaces

1976 ◽  
Vol 34 ◽  
pp. 130-131
Author(s):  
V.K. Berry
Keyword(s):  
Oxidation Reaction ◽  
Electron Microscope Study ◽  
Elemental Sulfur ◽  
Thiobacillus Ferrooxidans ◽  
Physical Contact ◽  
Metal Sulfides ◽  
Low Grade ◽  
Mineral Surfaces ◽  
Mineral Surface ◽  
Scanning Electron Microscope Study

There are two strains of bacteria viz. Thiobacillus thiooxidansand Thiobacillus ferrooxidanswidely mentioned to play an important role in the leaching process of low-grade ores. Another strain used in this study is a thermophile and is designated Caldariella .These microorganisms are acidophilic chemosynthetic aerobic autotrophs and are capable of oxidizing many metal sulfides and elemental sulfur to sulfates and Fe2+ to Fe3+. The necessity of physical contact or attachment by bacteria to mineral surfaces during oxidation reaction has not been fairly established so far. Temple and Koehler reported that during oxidation of marcasite T. thiooxidanswere found concentrated on mineral surface. Schaeffer, et al. demonstrated that physical contact or attachment is essential for oxidation of sulfur.

Preparation and Hydrophobic Properties of 5-Arylalkylidenerhodanines

2007 ◽  
Author(s):  
Jan Dolezel ◽  
Josef Jampilek ◽  
Jiri Dohnal ◽  
Veronika Opletalova
Keyword(s):  
Hydrophobic Properties

Process Description of an Unconventional Biofilm Formation by Bacterial Cells Autoagglutinating Through Sticky, Long, and Peritrichate Nanofibers

2019 ◽  
Author(s):  
Yoshihide Furuichi ◽  
Shogo Yoshimoto ◽  
Tomohiro Inaba ◽  
Nobuhiko Nomura ◽  
Katsutoshi Hori
Keyword(s):  
Formation Process ◽  
Biofilm Formation ◽  
Extracellular Polymeric Substances ◽  
Waste Treatment ◽  
Large Cell ◽  
Dlvo Theory ◽  
Bacterial Cells ◽  
Chemical Production ◽  
Discontinuous Surface ◽  
Cell Cell

<p></p><p>Biofilms are used in environmental biotechnologies including waste treatment and environmentally friendly chemical production. Understanding the mechanisms of biofilm formation is essential to control microbial behavior and improve environmental biotechnologies. <i>Acinetobacter </i>sp. Tol 5 autoagglutinate through the interaction of the long, peritrichate nanofiber protein AtaA, a trimeric autotransporter adhesin. Using AtaA, without cell growth or the production of extracellular polymeric substances, Tol 5 cells quickly form an unconventional biofilm. In this study, we investigated the formation process of this unconventional biofilm, which started with cell–cell interactions, proceeded to cell clumping, and led to the formation of large cell aggregates. The cell–cell interaction was described by DLVO theory based on a new concept, which considers two independent interactions between two cell bodies and between two AtaA fiber tips forming a virtual discontinuous surface. If cell bodies cannot collide owing to an energy barrier at low ionic strengths but approach within the interactive distance of AtaA fibers, cells can agglutinate through their contact. Cell clumping proceeds following the cluster–cluster aggregation model, and an unconventional biofilm containing void spaces and a fractal nature develops. Understanding its formation process would extend the utilization of various types of biofilms, enhancing environmental biotechnologies.</p><p></p>

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