Interfacial interactions between nitrifying bacteria and mineral carriers in aqueous media determined by contact angle measurements and thin layer wicking

Contact angle measurements enable the determination of the surface free energy on flat and smooth solid surfaces. The thin layer wicking technique permits this determination for powdered materials. Both techniques were assayed on limestone and basalt which were the materials used as supports for bacterial adhesion. The resulting surface free energy components were compared. The free energy of interaction between nitrifying bacteria and support materials in aqueous medium (Delta G(132)) was calculated and correlated with bacterial adhesion observed in a previous study. Although the values of the polar and apolar components were not exactly the same, both techniques lead to the same conclusions in terms of the ability for bacterial adhesion. (C) 1998 Elsevier Science B.V. All rights reserved.