The effect of ionic strength on the electrophoretic mobility and protonation constants of an EPS-producing bacterial strain

Nanofiltration and reverse osmosis surface topographical heterogeneities: Do they matter for initial bacterial adhesion?

“…fluorescens cells at pH 7 and 9, the negative surface charge of S. epidermidis was reduced as observed by its decreasing negative EM from -1.7 to -1.4 µmcm/Vs at pH 7 and 9 respectively. As similarly shown by Tourney et al [49], a deprotonation of cell wall functional groups takes place with increasing pH environments, which manifests itself with increasing EM, until all functional groups are fully deprotonated [47]. This difference in behaviour suggests that Ps.…”

Adsorption of copper on Pseudomonas aureofaciens: Protective role of surface exopolysaccharides

“…As a result, large ions of background electrolyte do not sufficiently approach the charged surface and thus weakly contribute to potential at the shear plane. A weak effect of ionic strength on electrophoretic mobility of EPSrich B. licheniformis observed in the range of 0.1-0.001 M has been explained by the contraction of the EPS layer with ionic strength [78]. Therefore, it is possible that the change in charge density associated with swelling of the EPS envelope at low ionic strength, which would compensate for charge-shielding [82] can be responsible for independence of electrophoretic mobilities of P. aureofaciens on ionic strength, observed in the present study.…”

“…Note that, because the binding to EPS was weak and the effect of background electrolyte on surface potential was not pronounced, the Donnan shell-like model was not necessary. Other work used electrostatic approaches such as the constant capacitance model converged to three sites [25,76] whereas non-electrostatic models tend to consider four surfaces sites [77] and more suitable for describing ESP-bearing bacteria [78]. The highest log K s (À1.75) was obtained for EPS-poor cultures produced in SAmedia (Exp # 5).…”

Zeta potential of anoxygenic phototrophic bacteria and Ca adsorption at the cell surface: Possible implications for cell protection from CaCO3 precipitation in alkaline solutions

“…Microelectrophoresis is a powerful technique for characterizing the electric double layer of microbial cell surfaces [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. The main advantages of this technique, compared to more commonly used surface titrations, is that (1) it provides straightforward information about the sign and the magnitude of cell surface electrostatic potential at the shear plane without specific assumptions and postulates; (2) it is almost instantaneous, capable of measuring zeta potential within several minutes after the preparation of suspension and without requiring specific stability criteria, unlike the surface titration [20]; (3) it can probe surface potential in extreme solution conditions (pH < 3 and >9, high carbonate concentration where the surface titration is not possible) and (4) principles of measurements are very similar among different apparatus so that the results of various studies are directly comparable [21][22][23].…”

“…Among various groups of microorganisms, heterotrophic bacteria, algae and cyanobacteria were extensively studied using microelectrophoresis techniques in the context of metal adsorption, biomineralization, and biofilm formation [11,14,[16][17][18][19][24][25][26]. These observations allowed comprehensive understanding of surface electrokinetic properties of most bacterial groups in a wide range of pH and ionic strength [27].…”