EFFECT OF CELL-SURFACE CHARACTERISTICS ON THE ADHESION OF BACTERIA TO SOIL PARTICLES

We investigated the adhesion to a sandy soil and a clay loam soil of a series of Lactobacillus strains with various cell surface characteristics. Measurable adhesion occurred within 30 s of contact time. No further increase in the number of bacteria adhering to the soil was observed after 15 - 20 min. The fraction of bacteria adhering to the soil was independent of the initial concentration of bacteria in solution. Bacteria adhering to the soil could be removed by washing the soil immediately after the adhesion test. Bacterial cell surface hydrophobicity, as determined by the bacterial adherence to octane and polystyrene, was the major parameter influencing the adhesion to the sandy soil. The cell surface charge of the bacteria was of minor importance in the adhesion to the sandy soil. The adhesion of the bacteria to the clay loam soil was higher than to the sandy soil and increased in the presence of divalent ions. This indicates that electrostatic interactions also influence the adhesion of bacteria to clay particles.