TY - JOUR

T1 - Hypertonic stress induced changes of Pseudomonas fluorescens adhesion towards soil minerals studied by AFM

AU - Abu Quba, Abd Alaziz

AU - Goebel, Marc Oliver

AU - Karagulyan, Mariam

AU - Miltner, Anja

AU - Kästner, Matthias

AU - Bachmann, Jörg

AU - Schaumann, Gabriele E.

AU - Diehl, Doerte

N1 - Funding Information: We thank the German Research Foundation (DFG) for funding this work as part of the project “Impact of bacterial biomass on the surface wettability of soil particles under varying moisture conditions” (DI 1907/2-1, GO 2329/2-1, MI 598/4-1). We also want to thank Susanne K. Woche (Leibniz Universität Hannover) for the contact angle and XPS measurements.

PY - 2023

Y1 - 2023

N2 - Studying bacterial adhesion to mineral surfaces is crucial for understanding soil properties. Recent research suggests that minimal coverage of sand particles with cell fragments significantly reduces soil wettability. Using atomic force microscopy (AFM), we investigated the influence of hypertonic stress on Pseudomonas fluorescens adhesion to four different minerals in water. These findings were compared with theoretical XDLVO predictions. To make adhesion force measurements comparable for irregularly shaped particles, we normalized adhesion forces by the respective cell-mineral contact area. Our study revealed an inverse relationship between wettability and the surface-organic carbon content of the minerals. This relationship was evident in the increased adhesion of cells to minerals with decreasing wettability. This phenomenon was attributed to hydrophobic interactions, which appeared to be predominant in all cell–mineral interaction scenarios alongside with hydrogen bonding. Moreover, while montmorillonite and goethite exhibited stronger adhesion to stressed cells, presumably due to enhanced hydrophobic interactions, kaolinite showed an unexpected trend of weaker adhesion to stressed cells. Surprisingly, the adhesion of quartz remained independent of cell stress level. Discrepancies between measured cell–mineral interactions and those calculated by XDLVO, assuming an idealized sphere-plane geometry, helped us interpret the chemical heterogeneity arising from differently exposed edges and planes of minerals. Our results suggest that bacteria may have a significant impact on soil wettability under changing moisture condition.

AB - Studying bacterial adhesion to mineral surfaces is crucial for understanding soil properties. Recent research suggests that minimal coverage of sand particles with cell fragments significantly reduces soil wettability. Using atomic force microscopy (AFM), we investigated the influence of hypertonic stress on Pseudomonas fluorescens adhesion to four different minerals in water. These findings were compared with theoretical XDLVO predictions. To make adhesion force measurements comparable for irregularly shaped particles, we normalized adhesion forces by the respective cell-mineral contact area. Our study revealed an inverse relationship between wettability and the surface-organic carbon content of the minerals. This relationship was evident in the increased adhesion of cells to minerals with decreasing wettability. This phenomenon was attributed to hydrophobic interactions, which appeared to be predominant in all cell–mineral interaction scenarios alongside with hydrogen bonding. Moreover, while montmorillonite and goethite exhibited stronger adhesion to stressed cells, presumably due to enhanced hydrophobic interactions, kaolinite showed an unexpected trend of weaker adhesion to stressed cells. Surprisingly, the adhesion of quartz remained independent of cell stress level. Discrepancies between measured cell–mineral interactions and those calculated by XDLVO, assuming an idealized sphere-plane geometry, helped us interpret the chemical heterogeneity arising from differently exposed edges and planes of minerals. Our results suggest that bacteria may have a significant impact on soil wettability under changing moisture condition.

UR - http://www.scopus.com/inward/record.url?scp=85173607692&partnerID=8YFLogxK

U2 - 10.1038/s41598-023-44256-7

DO - 10.1038/s41598-023-44256-7

M3 - Article

C2 - 37816775

AN - SCOPUS:85173607692

VL - 13

JO - Scientific reports

JF - Scientific reports

SN - 2045-2322

IS - 1

M1 - 17146

ER -