Influence of compressed fluids treatment on the activity of Yarrowia lipolytica lipase

This work investigated the influence of temperature, pressure, exposure times and depressurization rate on the activity of a non-commercial immobilized lipase from Yarrowia lipolytica (YLL) submitted to compressed carbon dioxide, propane and n-butane. A high-pressure cell was employed in the experiments, in the pressure range of 10-280 bar, varying the temperature from 35 to 75 degrees C, exposure times from I to 6 h, and adopting distinct decompression rates. Results showed that significant activity losses were obtained when the treatment was conducted in carbon dioxide, while negligible losses were observed in both propane and n-butane. For the treatment with carbon dioxide, within the range studied, the decompression rate affected positively enzyme activity, while the exposure time and temperature presented an opposite effect on the non-commercial immobilized lipase from Y lipolytica (YLL). Additionally, the performance of two commercial immobilized lipases (Lipozyme IM and Novozym 435) and the immobilized YLL in the three solvents was compared. Immobilized YLL has shown to be more suitable than Lipozyme IM for enzyme-catalyzed reactions using compressed propane and n-butane as solvents, but with inferior performance compared to Novozym 435 treated in these solvents. (c) 2006 Elsevier B.V. All rights reserved.