Effect of energy source, salt concentration and loading force on colloidal interactions between Acidithiobacillus ferrooxidans cells and mineral surfaces

• Published in: Colloids and surfaces, B, Biointerfaces Vol. 132; pp. 271 - 280
• Main Authors: Diao, Mengxue, Nguyen, Tuan A.H., Taran, Elena, Mahler, Stephen M., Nguyen, Anh V.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.08.2015
• Subjects: Acidithiobacillus - metabolism; Acidithiobacillus ferrooxidans; Appendages; Atomic force microscopy; Bacteria; Bacterial adhesion; Biopolymers; Colloids; Energy Metabolism; Energy sources; Microscopy, Electron, Scanning; Minerals - metabolism; Nanomechanical properties; Nanostructure; Salts - metabolism; Sulfur; Surface Properties; Teeth; Atomic force microscopy; Acidithiobacillus ferrooxidans; Bacterial adhesion; Nanomechanical properties
• ISSN: 0927-7765; 1873-4367
• DOI: 10.1016/j.colsurfb.2015.05.026

•Distinct retraction patterns of Acidithiobacillus ferrooxidans grown with different energy sources were observed.•Interaction forces between A. ferrooxidans and minerals with bacterial probes were quantified.•The conformation of surface biopolymers was affected by salt concentration. The surface appendages and extracellular polymeric substances of cells play an important role in the bacterial adhesion process. In this work, colloidal forces and nanomechanical properties of Acidithiobacillus ferrooxidans (A. f) interacted with silicon wafer and pyrite (FeS2) surfaces in solutions of varying salt concentrations were quantitatively examined using the bacterial probe technique with atomic force microscopy. A. f cells were cultured with either ferrous sulfate or elemental sulfur as key energy sources. Our results show that A. f cells grown with ferrous ion and elemental sulfur exhibit distinctive retraction force vs separation distance curves with stair-step and saw tooth shapes, respectively. During the approach of bacterial probes to the substrate surfaces, surface appendages and biopolymers of cells are sequentially compressed. The conformations of surface appendages and biopolymers are significantly influenced by the salt concentrations.