title: Quantifying adhesion of acidophilic bioleaching bacteria to silica and pyrite by atomic force microscopy with a bacterial probe.
abstract: The adhesion of acidophilic bacteria to mineral surfaces is an important phenomenon in bioleaching processes. In this study, functionalized colloidal probes covered by bioleaching bacterial cells (Acidithiobacillus thiooxidans and Leptospirillum ferrooxidans) were developed and used to sense specific adhesion forces to a silica surface and a pyrite surface in various solutions. Experimentally, recorded retraction curves of A. thiooxidans revealed sawtooth features that were in good agreement with the wormlike chain model, while that of L. ferrooxidans exhibited stair-step separation. The magnitudes of adhesion forces and snap-off distances were strongly influenced by the ionic strength and pH. Macroscopic surface properties including hydrophobicity and surface potential for bacterial cells and substrata were measured by a sessile drop method and microelectrophoresis. The ATR-FTIR spectra indicated the presence of different types of biopolymers on two strains of bacteria.
authors.affiliation: School of Chemical Engineering The University of Queensland, Brisbane QLD 4072, Australia.
authors.forename: Mengxue
authors.initials: M
authors.lastname: Diao
authors.affiliation: Australian Institute for Bioengineering and Nanotechnology, 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 for Bioengineering and Nanotechnology, ANFF-Q The University of Queensland, Brisbane QLD 4072, Australia.
authors.forename: Stephen
authors.initials: S
authors.lastname: Mahler
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: 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: D013856:Acidithiobacillus thiooxidans / Q000187:drug effects; D001419:Bacteria / Q000187:drug effects*; D001422:Bacterial Adhesion / Q000187:drug effects*; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D007501:Iron / Q000494:pharmacology*; D018625:Microscopy, Atomic Force / Q000379:methods*; D009994:Osmolar Concentration; D012822:Silicon Dioxide / Q000494:pharmacology*; D012996:Solutions; D017550:Spectroscopy, Fourier Transform Infrared; D013440:Sulfides / Q000494:pharmacology*; D013499:Surface Properties
chemical_list: D012996:Solutions; D013440:Sulfides; C011342:pyrite; D012822:Silicon Dioxide; D007501:Iron
keywords: Acidithiobacillus thiooxidans; Adhesion force; Atomic force microscopy; Leptospirillum ferrooxidans; Pyrite; Snap-off distance