Quantifying adhesion of acidophilic bioleaching bacteria to silica and pyrite by atomic force microscopy with a bacterial probe.

Mengxue Diao, Elena Taran, Stephen Mahler, Tuan A H Nguyen, Anh V Nguyen

Journal: Colloids and surfaces. B, Biointerfaces 2014;115():229-36

PMID: 24355385

Full Text on Elsevier Science View on PubMed

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.

Address: 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.; 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.; School of Chemical Engineering The University of Queensland, Brisbane QLD 4072, Australia. Electronic address: [email protected].

DOI: 10.1016/j.colsurfb.2013.11.047