Whole cell immobilization is one of the major immobilization methods due to cost advantages. Extracellular enzyme producing cells can be immobilized directly, but intracellular enzyme producing cells should be treated first to increase cell permeability. In this work beta-galactosidase-producing Kluyveromyces lactis (ATCC 8583) cells were used. Since beta-galactosidase is an intracellular enzyme permeabilized dead cells were immobilized into gelatin using glutaraldehyde as cross-linker. Two chemical and one physical disruption processes were tested and the physical method was determined to be better because of the probable risk of chemical toxicity accompanied with the chemical methods. Thirty percent activity was obtained by immobilized cells relative to free disrupted cells. (C) 2003 Elsevier Ltd. All rights reserved.