Production and characterization of liquid-core capsules made from crosslinked acrylamide copolymers for biotechnological applications

A novel chem. has been developed for the prodn. of capsules composed of a hydrophobic liq. core surrounded by a cross-linked polyacrylamide/alginate membrane. These liq.-core capsules may be used in capsular perstraction for the removal of inhibitory products from bioprocesses and bioconversions. They have the advantage of having a high surface area to promote rapid mass transfer, while sepn. of the org. core phase from the aq. environment by the capsule membrane prevents the formation of stable emulsions and potential problems assocd. with toxicity of the org. phase for microbial cells or enzymes. Monodisperse spherical liq.-core capsules of between 800 mm and 1.6 mm diam., with high mech. resistance, have been prepd. by co-extrusion, using the jet break-up technique. Capsules produced from a soln. of MBA/total monomer (5%) were found to be more elastic and have a higher burst force when exposed to chelating agents such as phosphate or citrate. The mech. resistance was unaffected by buffer solns. in the pH range 4-9 and after sterilization at 121 DegC for 20 min. Capsules having membranes composed of a copolymer of acrylamide and N-hydroxymethylacrylamide exhibited even higher mech. stability toward chelating agents. [on SciFinder (R)]