Immobilisation of pig liver esterase in hollow fibre membranes

Different methods were evaluated to immobilise Pig Liver Esterase (PLE) in hollow fibre membranes. Four covalent bonding techniques (using epoxy, imid azol, amino and carboxylic acid terminal groups) were tested to link the en zyme to microporous nylon membranes. Physical immobilisation was also studi ed, by entrapment of the enzyme inside the microporous structure of a polys ulfone asymmetric ultrafiltration membrane. The entrapment method lead to a higher retention of enzymatic activity for a longer period of time. This t echnique was selected to be used in a biphasic membrane bioreactor where th e microporous hydrophilic membrane, containing the enzyme, is used to separ ate an aqueous from an organic phase, in which the substrate is dissolved. Different enzyme loading procedures were studied in the biphasic reactor an d the resulting axial and radial enzyme distribution in the hollow fibre mo dule were related to the global enzymatic activity. (C) 2001 Elsevier Scien ce Inc. All rights reserved.