Highly enantioselective biocatalysts by coating immobilized lipases with polyethyleneimine

Polyethyleneimine (PEI) modification on immobilized lipases greatly enhanced their enantioselectivity in the kinetic resolution of (±)-2-hydroxy-phenylacetic acid methyl ester. The enantiomeric ratio (E) of CNBr-agarose-CRL rose from 8 (without coating) to 20 (ee = 90%) after PEI coating in the hydrolysis at pH 5. In the case of CAL-B, the coating highly improved the enantioselectivity of the immobilized lipase from E = 1.5 (without coating) to E > 100 (ee > 99%). Moreover, this coating strategy improved the stability of the biocatalyst at high temperatures and in the presence of high co-solvent concentrations.