title: Effect of energy source, salt concentration and loading force on colloidal interactions between Acidithiobacillus ferrooxidans cells and mineral surfaces.
abstract: 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.
authors.affiliation: Scientific Research Academy of Guangxi Environmental Protection, Nanning, Guangxi 530022, China; School of Chemical Engineering, The University of Queensland, Brisbane, Qld 4072, Australia.
authors.forename: Mengxue
authors.initials: M
authors.lastname: Diao
authors.affiliation: School of Chemical Engineering, The University of Queensland, Brisbane, Qld 4072, Australia.
authors.forename: Tuan A H
authors.initials: TA
authors.lastname: Nguyen
authors.affiliation: ANFF-Q, The University of Queensland, Brisbane, Qld 4072, Australia.
authors.forename: Elena
authors.initials: E
authors.lastname: Taran
authors.affiliation: School of Chemical Engineering, The University of Queensland, Brisbane, Qld 4072, Australia; Australian Institute of Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Qld 4072, Australia.
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Mahler
authors.affiliation: School of Chemical Engineering, The University of Queensland, Brisbane, Qld 4072, Australia. Electronic address: anh.nguyen@eng.uq.edu.au.
authors.forename: Anh V
authors.initials: AV
authors.lastname: Nguyen
mesh_terms: D042763:Acidithiobacillus / Q000378:metabolism*; D003102:Colloids; D004734:Energy Metabolism; D008855:Microscopy, Electron, Scanning; D008903:Minerals / Q000378:metabolism*; D012492:Salts / Q000378:metabolism*; D013499:Surface Properties
chemical_list: D003102:Colloids; D008903:Minerals; D012492:Salts
keywords: Acidithiobacillus ferrooxidans; Atomic force microscopy; Bacterial adhesion; Nanomechanical properties