Capillary membrane reactors: Performance and applications

Abstract Purpose of the work is the characterization of capillary membranes with entrapped cells, from a mechanical and a kinetic point of view. Polysulphone capillary membranes have been prepared by the phase inversion technique, extruding in a specially designed apparatus the polymer solution containing lyophilized cells of thermophilic Sulfolobus solfataricus . The mechanical properties of such capillary membranes were tested and compared to those of cell-free fibres in terms of bubble formation point and outburst under pressure, and of their behaviour under a stress—strain analysis. Fibres permeability to water and to the acetate buffer (pH 5) used in kinetic experiments was determined in the range of temperatures from 25°C to 70°C. Regarding the entrapped cells kinetic behaviour, an enzyme in particular was selected in bacterial enzymatic heritage, i.e. β-galactosidase, for the conversion of lactose to glucose and galactose. Kinetic assays were performed on bundles of fibres assembled in tube and shell reactors at different substrate concentrations and transmembrane pressures.