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 α-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, 4×10−3 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 28×10−3 U cm−2 synthetic activity and a 203 day half-life time in hexane media.