Differences in adhesion of A-thiooxidans and A-ferrooxidans on chalcopyrite as revealed by atomic force microscopy with bacterial probes

Abstract

Bacteria capable of oxidizing sulphur and iron, known as Acidithiobacillus thiooxidans and Acidithiobacillus ferrooxidans bacteria, respectively, are important in bioleaching of sulphide minerals. Here, using atomic force microscopy (AFM) we report significant differences in the adhesion behaviour of these bacteria when interacting with chalcopyrite surfaces. The bacterial force probes were prepared by attaching bacterial cells onto a silica microsphere (∼10 μm radius) glued to the end of an AFM cantilever. Probes were brought into, and separated from, the contact with chalcopyrite surfaces in half-strength 9 K medium solutions of various pH conditions. The adhesion forces of nano-Newton res..