Effect of Growth Phase and Metabolic Activity on the Adhesion of Escherichia coli K-12 AB264 to Quartz and Lepidocrocite
Résumé
The transport of bacteria through soils is controlled in part by their adhesion to mineral surfaces. We studied the adhesion of Escherichia coli K-12 to two representative soil minerals (quartz and lepidocrocite), as the growth phase of the population, the metabolic state of the cells, and the pH of the solution were independently varied. Acid-base titrations and electrophoretic mobility measurements were used to investigate the effects of cell and mineral surface speciation and electric charge on the adhesion process. Significant adhesion to lepidocrocite was observed, decreasing at higher pH values presumably in response to the decreasing electrostatic attraction between the cells and the mineral surface. Adhesion of inactive cells (poisoned with streptomycin) was more extensive than for non-poisoned cells, for both mineral substrates. Further research is warranted to determine if other bacterial species display similar relationships between adhesion, cell metabolic state, mineral sorbent, and solution pH.