Initial adhesion of Bacillus subtilis on soil minerals as related to their surface properties

Abstract

The initial adhesion of micro‐organisms on solid surfaces strongly affects their transport and fate in soil and aquatic environments. Experiments on Bacillus subtilis with various soil minerals (including kaolinite, montmorillonite, goethite, birnessite, quartz and mica) were conducted to determine the role of surface properties in adhesion and to test the validity of the extended Derjaguin, Landau, Verwey and Overbeek (DLVO) theory for bacterial adhesion. Adhesion of B. subtilis on all six minerals conformed to the Langmuir equation. Adhesion capacity and affinity showed a significant correlation with the specific external surface area (SESA) of the minerals and the calculated electrostatic energy barrier, respectively, but no significant correlation was observed between hydrophobicity and the adhesion parameters. These results demonstrate that adhesion capacity and affinity are primarily controlled by the SESA of the minerals and the surface electrical properties, respectively. The dependence of the adhesion capacity on SESA may be explained by the cell–mineral interaction model. Adhesion could be well predicted by the extended DLVO theory. The initial adhesion of bacteria with soil minerals can be evaluated by using independently measured surface properties of these components based on the extended DLVO theory combined with the Langmuir equation.

Interactions BetweenEscherchia coliand the Colloids of Three Variable Charge Soils and Their Effects on Soil Surface Charge Properties

“…The mineral components and the CEC of the soil colloids were the main factors affecting the adhesion of E. coli by the soil colloids (Table 1 and Table 2). Fe/Al oxides usually have a higher adhesion capacity for bacteria than silicate minerals, such as kaolinite and montmorillonite (Cai et al 2013;Hong et al 2012;Wu et al 2011b). The contents of the free Fe/Al oxides in the Ultisol collected from Jiangxi were much lower than those in the Ultisol from Guangxi and the Oxisol from Yunnan, which is the main reason for the significantly lower adhesion capacity of the former for E. coli than the latter two (P<0.05).…”

“…Bacterial attachments that are dominated by these forces are reversible processes and the bacteria can be rapidly detached from the solid surface when the aqueous phase chemistry changes (Mills 2003). The metal oxides, such as goethite, have higher adhesion capacities for bacteria than do silicate minerals, such as kaolinite and montmorillonite, because ACCEPTED MANUSCRIPT ACCEPTED MANUSCRIPT 4 of their positive charge (Wu et al 2011b;Hong et al 2012;Cai et al 2013). Metal oxide coatings confer a positive charge to the negatively charged soil particles and result in a much tighter bacterial adhesion to the surfaces, which increases the adhesion capacity of bacteria (Mills 2003).…”

“…Bacteria usually carry a negative charge on their surfaces, which means that electrostatic repulsion, van der Waals forces and hydrophobicity dominate the interaction between bacteria and negatively-charged soil particles (Poortinga et al 2002;Mills 2003) and this can be described by the extended DLVO theory (Poortinga et al 2002;Hong et al 2012). Bacterial attachments that are dominated by these forces are reversible processes and the bacteria can be rapidly detached from the solid surface when the aqueous phase chemistry changes (Mills 2003).…”

Surface complexation modeling of Cd(II) sorption to montmorillonite, bacteria, and their composite

“…Montmorillonite (Sanding Group Co. Ltd., Shaoxing, Zhejiang, China) was prepared following previously outlined procedures (Hong et al, 2012(Hong et al, , 2013. The clays were oxidized using H 2 O 2 (30 %) to remove any residual organic matters.…”

Contrasting effects of extracellular polymeric substances on the surface characteristics of bacterial pathogens and cell attachment to soil particles

“…The cells and soil particles in attachment assay were suspended and mixed at 150 rev min −1 . It is possible that some level of shear force caused by this mixing may provide additional kinetic energy to help cells attach to the solid surfaces (Mohamed et al, 2000;Thomas et al, 2002;Chen et al, 2010;Hong et al, 2012). There is also a possibility of polymer bridging as facilitated by EPS.…”