Research Team: Andreas Klingl, Cordula Neuner, Dr. Harald Huber, PD Dr. Reinhard Rachel und Prof. Dr. Michael Thomm
Collaborations with Prof. Dr. G. Schmalz, Zahnklinik der Uni Regensburg, and Prof. Dr. W. Depmeier and Katja Etzel, Kiel


Microorganisms on Pyrite Surfaces: Influence of structure and crystallographic orientation on the dissolution of pyrite.

 

In collaboration with the Institute of Geosciences , University of Kiel (Crystallography: Prof. Dr. Wulf Depmeier) , this project aims to investigate the influence of the orientation of the pyrite on the microbial oxidation of pyrite by various mesophilic Bacteria and thermophilic Archaea. Dissolution of Pyrite is examined and compared under a variety of experimental parameters like pH, temperature, type and strain of microorganism, type of culture medium, origin and composition of the Pyrite. Finally, we want to understand the basic mechanism of microbially mediated pyrite dissolution, like, which crystal surface is favored by which microorganism, and which surface structure of the microorganisms is involved. First investigations using epifluorescence light microscopy (Fig. 3 b,d) and scanning EM (Fig. 1) show that for some bacterial strains, all cells adhere to the pyrite surface, while cells of other microorganisms remain planctonic and do not adhere at all. After a few days, typical pattern of corrosion like channels or inverted pyramids are observed (Fig. 2). Using these direct observations, we want to contribute to a better understanding of the mechanisms of pyrite dissolution, either directly or indirectly; of the specificity of the microorganisms for pyrite surfaces and selected metal ions, and of the type of microbe-surface interaction.

SEM
fig. 1:SEM (scanning electron micrograph) of A. ferrooxidans, adhering on the surface of a Pyrit crystal. Bar: 20 µm

SEM
fig. 2: SEM images of etching features generated after six weeks of incubation ofSulfolobus metallicus . Image shows inverted pyramidal structures on a natural {100} face (inset scale bar 10 µm).

 



fig. 3: Examples of cell attachment to pyrite surface observed with a) and c)
light microscopy and b) and d) epifluorescence microscopy; example in
a) and b) is Sulfolobus metallicus, c) and d) is Thiobacillus prosperus.

 

Supported by DFG