SOL-GEL ENTRAPMENT OF LIPASE USING A MIXTURE OF TETRAMETHOXYSILANE AND METHYLTRIMETHOXYSILANE AS THE ALKOXIDE PRECURSOR - ESTERIFICATION ACTIVITY IN ORGANIC MEDIA

The sol-gel method, using a mixture of tetramethoxysilane (TMOS) and methyltrimethoxysilane (MTrMOS) as the silicon alkoxide precursor, has been applied to entrapment of lipase catalyzing esterification reactions in organic media. Increasing molar ratio of MTrMOS to TMOS led to formation of opaque and non-shrinkable gels and resulted in an increase in the esterification activity of lipase. The hybrid gel-entrapped lipase based on [MTrMOS]/[TMOS] ratio of 4 exhibited almost equal activity with those of the deposited lipase on different supports at 35 degrees C, and retained ca. ten times higher activity than the deposited counterparts at 65 degrees C.