The role of bacteria in the formation of iron sulfide minerals under low pH conditions

• Applicant: Dr. Jutta Meier
• Subject Area: Hydrogeology, Hydrology, Limnology, Urban Water Management, Water Chemistry, Integrated Water Resources Management
• Term: from 2005 to 2009
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 22831158

Bacteria can trigger mineral formation by their metabolic activity or by provision of sorption and nucleation sites on cell surfaces. Sulfide minerals occur in marine and freshwater sediments primarily as the result of dissimilatory sulfate reduction which is mediated by a phylogenetically diverse group of Prokaryotes that gain their energy by anaerobic respiration with sulfate as terminal electron acceptor. In principle it is the reversal process of pyrite oxidation which generates acidic metal-rich waters causing severe environmental pollution in coal and metal ore mining areas. The formation of iron sulfides is a major process in controlling global element cycling, besides, it is the target process during the treatment of acid mine drainage by the use of dissimilatory sulfate reduction. The sustainability of bioremediation depends on the extent and stability of iron sulfides formed. However, so far little is known about iron sulfide formation under acidic conditions and the role that bacteria play in this process. The objectives of this project are i) to investigate the formation of iron sulfide minerals in sulfate-reducing enrichment cultures under low pH-conditions, ii) to analyse and characterise mineral structures and cell-mineral interactions, iii) to elucidate community structure and its response to varying pH values, and iv) to find out whether the involved bacteria benefit from iron sulfide precipitation. This study may contribute to our general understanding of biomineral formation and sulfate reduction under acidic conditions and may help us to further improve bioremediation strategies.

• DFG Programme: Research Fellowships
• International Connection: Canada
• Host: Professorin Dr. Danielle Fortin