In situ monitoring of the biofilm formation of Pseudomonas putida on hematite using flow-cell ATR-FTIR spectroscopy to investigate the formation of inner-sphere bonds between the bacteria and the mineral

Abstract

AbstractIn situ flow-cell ATR-FTIR using a hematite-coated germanium crystal was used to investigate the chemical interactions between Pseudomonas putida and hematite in real time, when compared with cells not attached to the mineral surface. ATR-FTIR spectra of bacteria growing on hematite showed a shift in the carboxylate signal when compared to the samples obtained from free cells, indicating a chemical interaction between the carboxylate groups and the Fe metal ions of the hematite surface. Small differences in the polysaccharide and phosphoryl regions of the IR spectra of bacteria attached to hematite were also observed. This work shows how the use of in-situ flow-cell experiments with a mineral-coated germanium crystal allows a better description of the bacterial interactions with minerals in real time, as an initial step to understand the fundamental mechanisms involved in the relationship between bacteria and mineral surfaces.