Microcapsules for enzyme immobilization were successfully fabricated via interfacial cross-linking of poly(ethyleneimine) (PEI). A method based on laminar jet break-up technique using a commercial instrument developed to produce alginate beads is reported for the first time for production of PEI microcapsules. The diameter, wall thickness and pore size of membranes were obtained from confocal laser scanning microscopy by labelling PEI and proteins. The composition of membranes was analysed by elemental analysis. Larger microcapsules (ca 200 mu m diameter) were obtained with the encapsulation device. In comparison, the emulsion method produced smaller capsules (ca 20 mu m diameter) but with a wider size distribution. Encapsulation efficiency for both methods was analysed by bicinchoninic acid and fluorescence assays, yielding efficiencies of 94 +/- 2% and 83 +/- 3% for the emulsion method and encapsulation device, respectively. Glucose oxidase from Aspergillus Niger and Laccase from Trametes Versicolor were encapsulated by both microencapsulation methods and their activities were compared.