Abstract
PEG microspheres immobilizing lipase complexes were prepared using an oil-in-water-in-oil (O/W/O) multiple emulsion. The performance of the PEG microspheres with respect to esterification in isooctane was examined by changing the preparation conditions. We found that the molecular weight of PEG, the PEG concentration, the pH and the type of salts in the aqueous buffer solution are predominant factors influencing the enzyme activity in organic media. These preparation conditions significantly affect enzymatic functions of PEG microspheres containing lipase complexes. The lipase-containing PEG microspheres provide a similar enzymatic activity to that of the lipase complex itself dissolved in organic solvents. The PEG microspheres containing lipase complexes show a heat-resistant property. The PEG microspheres, therefore, exhibit a higher enzyme activity than the lipase complex without a microsphere at all the reaction temperatures tested. In enantioselective esterification, the PEG microspheres show high enantioselectivity in isooctane.
