Lipases (triacylglycerol acylhydrolases; E.C. 3.1.1.3) constitute a group of enzymes defined as carboxylesterases that catalyse the hydrolysis (and synthesis) of long-chain acylglycerols at the lipid-water interface. In this study, a novel method has been developed to prepare nanoprotein particles carrying lipase using a photosensitive microemulsion polymerization process. The nanostructured lipases with photosensitive features have been characterized by transmission electron microscopy (TEM) and Zeta Sizer. The average particle size of nanolipases was found to be about 100 nm. Lipase nanoparticles were used in hydrolysis of paranitrophenyl palmitate (p-NPP) and the results were compared with free lipase. The parameters like pH, temperature and hydrolytic activity that affect p-NPP hydrolysis were investigated by using lipase nanoparticles and compared to free lipase. Lastly, reusability of lipase nanoparticles was investigated and according to our results, this novel lipase nanoparticles showed admirable potential in reusable catalyst. (C) 2011 Elsevier Ltd. All rights reserved.