Immobilized intracellular enzymes

Process for immobilization of an intracellular, glutaraldehyde sensitive enzyme, which process comprises reacting in an aqueous medium microbial cell material containing therein an intracellular glutaraldehyde sensitive enzyme with glutartaldehyde in the presence of a branched polyalkalene imine added to the medium before or simultaneously with the glutaraldehyde, said polyalkalene imine having primary amino groups on the polyalkalene imine molecule at a ratio of primary amine equivalents to aldehyde equivalents in the range of from 0.01:1 to 10:1, and thereafter recovering the resulting immobilized enzyme containing microbial cell preparation.