Adhesion of Shewanella oneidensis MR-1 to Goethite: A Two-Dimensional Correlation Spectroscopic Study

Environ Sci Technol. 2016 Apr 19;50(8):4343-9. doi: 10.1021/acs.est.6b00066. Epub 2016 Apr 7.

Abstract

Bacterial adhesion to mineral surfaces is an important but underappreciated process. To decipher the molecular level process and mechanism, the adhesion of Shewanella oneidensis MR-1 cells to goethite was investigated using flow-cell attenuated total reflectance (ATR) Fourier transform infrared (FTIR) spectroscopy coupled with two-dimensional correlation spectroscopy (2D-COS) analysis. The FTIR results indicate that bacterial phosphate-moieties play an important role in the formation of mono- and bidentate inner-sphere complexes, whereas carboxylic groups on cell surface only have a minor contribution to its adhesion. The 2D-COS analysis in short-term (0-120 min) and long-term (2-18 h) stages reveal that the adhesion process was in the following sequence: change in H-bonds of proteins on cell surfaces > formation of monodentate inner-sphere surface complexes > formation of outer-sphere surface complexes > transformation of protein secondary structure on cell surfaces > formation of additional bridging bidentate surface complexes. In addition, the adhesion of MR-1 cells on goethite was pH dependent due to pH impacts on the cell structure and the interface charge. The in situ ATR-FTIR integrated with 2D-COS analysis highlights its great potential in exploring complex surface reactions with microbes involved. These results improve our understanding of microbe-mineral interactions at the molecular level and have significant implications for a series of biogeochemical processes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adsorption
  • Bacterial Adhesion
  • Hydrogen-Ion Concentration
  • Iron Compounds*
  • Minerals*
  • Phosphates / chemistry
  • Shewanella / chemistry
  • Shewanella / metabolism*
  • Spectroscopy, Fourier Transform Infrared / methods
  • Spectrum Analysis / methods

Substances

  • Iron Compounds
  • Minerals
  • Phosphates
  • goethite