Three novel nano-silica dioxide (NSD) carriers with reactive aldehyde groups, i.e. NSD-1, NSD-2 and NSD-3, were firstly prepared through functionalization of the NSD material, and porcine pancreas lipase (PPL) was immobilized on the resulting carriers by using covalent coupling method. The activity recovery of immobilized PPL based on the carrier NSD-1, NSD-2 and NSD-3 reaches to 73%, 79% and 118%, respectively, and the values of apparent Km of them were all higher than that of the free PPL. The optimal pH and temperature region of the immobilized PPLs for the hydrolysis of olive oil were at 8.0 and 50-60 degrees C. Meanwhile, the immobilized PPLs have a good stability, adaptability and reusability. (c) 2005 Elsevier Ltd. All rights reserved.