2015 Volume 52 Issue 3 Pages 132-138
The effect of extracellular polymeric substance （EPS） and filamentous appendages （flagella and pili） on microbial adhesion onto solid surfaces was investigated using DLVO theory and thermodynamic approaches. Nonmotile Lactococcus lactis and motile Escherichia coli were used as model microbes. Negatively and positively charged silica particles and glass slide were used as model substrates. The estimated surface potentials and tensions of microbial cells and substrates were used for the prediction of microbial adhesion. As a result, the microbial cells with EPS or filamentous appendages were able to adhere to solid surfaces even though the DLVO theory predicted an insurmountable potential barrier in low ionic strength. The adhesion of nonmotile Lactococcus lactis onto the silica particles was promoted in the presence of EPS. In contrast, the effect of EPS on adhesion of motile Escherichia coli onto the glass substrate was reduced in the presence of filamentous appendages.
