Quality improvement of crude porcine pancreatic lipase preparations by treatment with humid supercritical carbon dioxide

Abstract

Crude preparations of porcine pancreatic lipase (PPL) contain apart from the PPL a significant number of other hydrolases as impurities. The treatment of crude PPL preparations with humid supercritical carbon dioxide leads to a quality improvement of the preparations. Five hundred milligrams of PPL preparation were incubated in a high pressure reactor (140 ml) at 150 bar and 75°C for 24 h. Different amounts of water were put into the reactor prior incubation. A set of different assays based on hydrolytic activities was used after the treatment. It was found out that the treated preparations are significantly more active with the long chain triglyceride triolein (675% residual activity with 100 μl water added) and an artificial substrate (1,2- o-dilauryl-rac-glycero-3-glutaric acid-resorufin ester (DGGR)), while there is a loss of activity towards the short chain triglycerides, tributyrin and triacetin. Treatment with humid supercritical carbon dioxide activates the PPL that is active towards long chain triglycerides and denatures the other hydrolases that are active only towards short chain triglycerides. Repeated incubation in dry supercritical carbon dioxide causes no loss of activity towards short chain triglycerides indicating the important role of the water in the supercritical phase for the denaturing effect on the hydrolase impurities. The treated preparations have a high temperature stability (no activity loss after 72 h at 60°C).