Active membranes coated with immobilized Candida antarctica lipase B:: preparation and application for continuous butyl butyrate synthesis in organic media

A method for preparing dynamic membranes by the cross-flow filtration of two water-soluble polymers (,gelatin and/or polyethyleneimine, PEI) on an alpha-alumina ceramic support, followed by covalent attachment of Candida antarctica lipase B (CALB) has been optimized. The obtained derivatives were tested for different immobilization parameters and selected as a function of the operational stability for the continuous hydrolysis of p-nitrophenyl palmitate (PNPP). The gelatin-PEI active membrane provided the best results (93% coupling efficiency, 4 x 10(-3) U cm(-2) activity and 22 h half-life time). This enzymatic membrane was also used as catalyst for the continuous kinetically controlled synthesis of butyl butyrate from vinyl butyrate and 1-butanol in three different organic solvents (hexane, acetone and acetonitrile) at low water content (<3% v/v). A clear enhancement in the operational stability of the enzymatic dynamic membranes was observed in these anhydrous media. The lipase-membrane derivative prepared with gelatin-PEI showed 28 x 10(-3) U cm(-2) synthetic activity and a 203 day half-life time in hexane media. (C) 2002 Elsevier Science B.V. All rights reserved.