BIOCONVERSIONS IN AN AQUEOUS 2-PHASE SYSTEM USING ENZYMES IMMOBILIZEDON ULTRAFINE SILICA PARTICLES

Bioconversions of corn starch and bovine hemoglobin in an aqueous two- phase system using alpha-amylase and papain immobilized on ultrafine s ilica particles (average diameter 15 nm) were studied. Both alpha-amyl ase and papain were immobilized onto the ultrafine silica particles wi th high efficiency by covalent cross-linking with glutaraldehyde, and both enzymes showed high activities. Since these immobilized enzymes w ere totally partitioned to the polyethylene glycol (PEG)-rich top phas e in PEG/dextran aqueous two phase systems, the products were recovere d from the bottom phase. These reaction systems were found to be effec tive for extractive bioconversions.