PI: Karina Krarup Sand

Project title: Extracellular influence on precipitation, growth and transformation mechanisms of iron oxides in microbial systems

Granted by: DFF Individual Postdoc grant

Year: 2013


In this project the majority of my work was focused to obtain and derive mechanistic information for the interactions between model or real extracellular polymers (EP) and iron oxides. The data interpretation part of the project had to be developed from being applicable to single molecular system to a system reflecting EP with multiples molecules, head groups and constructs. I developed the DFSpolymer approach to get insight into energy landscapes of interacting bonds between flexible polymers and mineral surfaces. Previously, we were confined to report bond force measurements in relative terms because we could not determine absolute bond parameters from multiple molecule interactions and the same tip had to be used across experiments to ensure a similar area of interaction. With the developed method, we can obtain single bond interactions from a probe that is covered in organic material. In addition, my approach allows for calculation of the absolute Gibbs free energy of binding which in combination with nucleation theory can provide information on the thermodynamic barriers for mineral formation.