Prepurification of esterase EP10 by treatment with supercritical carbon dioxide (SC-CO2)

A crude preparation (0,2 U/mg) of esterase EP10 from Burkholderia gladioli was purified by treatment with SC-CO2. The enzyme preparation showed high stability (activity increase to 120,7 %.) against 30 pressurisation / depressurisation steps at 35 degrees C and 150 bar. Incubation for 24 hours in SC-CO2 at 150 bar and 35 degrees C had less effect on enzyme activity (103,8 %) than incubation at 75 degrees C (residual activity: 62,3 %). By using a purified enzyme preparation (0,4 U/mg) of esterase EP10 no significant effect has been observed. High pressure extraction of crude esterase EP10 with CO2 at different temperatures, pressures and incubation times exhibited various amounts of activity increase, reaching the highest ones at 500 bar and 1 hour at 50 degrees C (25,3 %) and 25 degrees C (33,4 %). Several fatty acids have been identified in the SC-CO2 extract by gas chromatography. The addition of entrainers except hexane cause an activity decrease. Fluorescence spectra indicated no conformational change and several biochemical assays no chemical modification of esterase EP10 after treatment with SC-CO2.