Prodn. of a carrier for immobilising enzymes comprises: (a) dissolving a low mol. wt. chitosan in an aq. acid soln.; (b) adding the soln. dropwise to a basic soln. to regenerate porous chitosan in particulate form; (c) reacting the chitosan with a glycidyl ether (I) of an aliphatic polyol; and (d) reacting the prod. with a higher fatty acid halide or anhydride (II) in a polar organic solvent. Also claimed are: (1) a carrier comprising regenerated porous chitosan in particulate form, in which (gps. derived from) (I) and (II) have been introduced into the pyranose rings of the chitosan; (2) glucoamylase immobilised on the carrier of (1); (3) glucose isomerase immobilised on the carrier of (1); and (4) lipase immobilised on a carrier prepd. as above using 0.01-0.4 mole of (I) and 0.05-1 mole of (II) per mole of pyranose units, where the immobilised lipase has a lipid hydrolysis activity of 0.01-2 U/mg (dry basis).
