Methyl-β-cyclodextrin assisted enantioselective ester hydrolysis catalyzed by lipase immobilized in a polymer membrane

Kinetic resolution of racemates by means of enzyme processes occurring in a membrane reactor is discussed. The reactor containing a lipase catalyst immobilized within the polyamide membrane was used to separate (R,S)-1-phenylethanol and (R,S)-1-phenyl-1-propanol that were produced by ester hydrolysis. The efficient separation was accomplished by the on-line extraction of the produced alcohols in an independent membrane extraction module. Methyl-beta -cyclodextrin was used as an alcohol extractant to separate alcohols from both the unreacted esters and the produced acids. Thermal decomposition (at 60-70 degreesC) of the formed complexes of methyl-beta -cyclodextrin and alcohol is suggested as a convenient method for reextraction. Application of the hybrid reactor-extractor membrane system yielded higher reaction rates and greater enantiomer excess in relation to the unreacted R-ester.