Peroxidase from white turnip (Brassica rapa) was immobilized as cross-linked enzyme aggregate (CLEA) via solvent precipitation and glutaraldehyde cross-linking. The nature of the precipitation solvent, enzyme and glutaraldehyde concentrations affected the formation and the activity of the enzyme aggregate. The aggregates resulting from cross-linking with glutaraldehyde produced insoluble catalytically active cross-linked enzyme aggregate