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Surface characterization of the Gram‐positive bacteria Bacillus subtilis ‐an XPS study
Author(s) -
Leone Laura,
Loring John,
Sjöberg Staffan,
Persson Per,
Shchukarev Andrei
Publication year - 2006
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.2184
Subject(s) - bacillus subtilis , chemistry , x ray photoelectron spectroscopy , deprotonation , bacteria , extracellular polymeric substance , biofilm , amine gas treating , carboxylate , chemical engineering , biochemistry , organic chemistry , ion , biology , genetics , engineering
Interactions at the bacteria‐solid interface in aquatic environments are of crucial importance in biofilm formation processes. The characterization of microbial surfaces properties is therefore a very important step for the understanding of these interactions. In this study, XPS spectra of Bacillus subtilis wet pastes centrifuged from suspensions over a span of pH values were recorded using a fast‐freezing procedure. The chemical composition of the bacterial surface was elucidated and the presence of surface sites containing carboxylate, phosphate and amine functional groups was established. It was possible to distinguish between charged and uncharged amine sites on the surface and follow their deprotonation reactions as a function of pH. It is suggested that increased metabolic activity around the physiological pH results in the excretion of proteins and/or peptides which are possibly related to the production of extracellular polymeric substances (EPS). Copyright © 2006 John Wiley & Sons, Ltd.