4] Enzymes immobilized to cellulose

Abstract

This chapter discusses the immobilization of a variety of enzymes to cellulose. The availability of modified celluloses, originally for use as ion exchangers, has permitted a wide range of methods to be developed for covalent binding of enzymes. With a few exceptions, it is assumed that the enzyme binds mainly through amino groups on its surface, but this has been confirmed in only a few instances. Attachment via cellulose hydroxyl groups includes use of cyanogen bromide and transition metal salts. Cyanogen bromide is used mainly for covalent binding of enzymes to Sephadex and Sepharose. Use of transition metal salts is based on the activation of celluloses by steeping in a solution of the metal salt followed by addition of the enzyme to the washed cellulose-metal salt complex. The exact nature of the binding has not yet been elucidated. Other methods include attachment via carboxylic acid groups on cellulose derivative, attachment to aliphatic amine derivative, and attachment via alkyl halide derivatives. An experimental procedure is also discussed using (1) cyanuric chloride or its derivatives, and (2) glutaraldehyde.