Immobilization of Saccharomyces cerevisiae by adhesion: treatment of the cells by Al ions.
The adsorption of aluminum ions by Saccharomyces cerevisiae has been investigated by determining adsorption isotherms and electrophoretic mobility. The adsorption of aluminum ensures a neutralization of the cell surface charge and allows adhesion of the cells to glass and polycarbonate. Glass slides have been taken as a negatively charged model support, allowing the authors to study in detail the process of adhesion. The cells are simply pretreated by an aluminum solution near pH 4. Bringing the Al-pretreated cells in contact with the support by sedimentation and washing the support and sediment makes it possible to obtain a single, dense, regular layer of cells adhering strongly to the support. Adhesion can also be obtained from a suspension flowing parallel to a vertical support, provided the flow velocity is sufficiently small; the amount of cells immobilized per unit support area is about one-half that obtained by sedimentation. The immobilized cells show a specific activity for ethanol production from glucose which is similar to cells in suspension.
Van Haecht
J L
JL
Unite de Chimie des Interfaces, Faculté des Sciences Agronomiques, Université Catholique de Louvain, Place Croix du Sud 1, B-1348 Louvain-la-Neuve, Belgium.
Bolipombo
M
M
Rouxhet
P G
PG