Separation and Purification Technology 25 (2001) 229 – 233 Preparation of hybrid membranes for enzymatic reaction M.P. Belleville a, *, P. Lozano b , J.L. Iborra b , G.M. Rios a a Uniersite ´ de Montpellier 2, IEMM UMR 5635, CC047, Place Bataillon, 34095 Montpellier Cedex 05, France b Facultad de Quı ´mica, Uniersidad de Murcia, Campus de Espinardo, 30100 Murcia, Spain Abstract Two different active membranes were prepared by simple (membrane M1) or mixed-entrapping (membrane M2) covalent attachment of -chymotrypsin onto an -alumina tubular support coated with an inert protein. The derivatives were used as catalyst for the continuous kinetically controlled synthesis of kyotorphin in organic media. Contrary to adsorption, the covalent linkage of the enzyme to a dynamic membrane allows a continuous peptide synthesis and enhances operational stability towards the denaturative effects of organic solvents. © 2001 Elsevier Science B.V. All rights reserved. Keywords: Membrane reactor; Dynamic membrane; -Chymotrypsin; Peptide synthesis www.elsevier.com/locate/seppur 1. Introduction Enzymatic conversion processes are commonly used in the production of food, pharmaceutical and other biological products. Generally, enzy- matic processes are conducted in batch reactors where enzymes are used in their soluble form. However, this kind of reactors requires high labor cost due to start up and shut down procedures and needs further separation steps to recover the reaction product. To overcome these disadvan- tages, the use of membrane reactors has been investigated. In this latter type of reactor, reaction and separation are coupled. The substrate is con- tinuously brought in contact with the biocatalyst, which is retained by the membrane, either freely circulating with retentate or fixed on the barrier, and the resulting product permeates through the membrane. Thus, the control of the reaction is easier, the enzyme is reused and a continuous output of high quality products is obtained. If free enzyme membrane reactors are well adapted for hydrolysis of large substrates like starch [1], they are less attractive for reactions that involve small substrates and/or enzymes of a high cost, that one cannot thus allow to lose. In that case, it should be better to deposit the catalyst onto the membrane surface using a well adapted procedure that preserves all the activity, and to take the best of the membrane configuration to create a very favorable environment as regards reaction yield. For several years, works have been developed at LMPM, which relate to the preparation of hybrid membranes elaborated from macromolecu- lar deposits formed on macroporous ceramic sup- ports during tangential filtration of protein * Corresponding author. Tel./fax: +33-467-144617. E-mail address: belleville@crit.univ-montp2.fr (M.P. Belleville). 1383-5866/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved. PII:S1383-5866(01)00106-X