Immobilized Aminoacylase on Porous Glass Beads

The preparation and properties of immobilized aminoacylase on porous glass by covalent binding [Porous glass-CVB-aminoacylase] and the continuous enzymatic reactions using such preparations are described.

Two types of porous glass-CVB-aminoacylase were prepared. One was aminoacylase covalently bound to alkylaminosilane derivative of porous glass with glutaraldehyde as a coupling agent [Alkylamino-porous glass-CVB-aminoacylase], and the other was aminoacylase covalently bound to arylaminosilane derivative of porous glass with nitrous acid as a coupling agent [Arylamino-porous glass-CVB-aminoacylase]. The enzyme activities of such immobilized aminoacylases were 3.2~13.0 units/ml glass for the former and 1.9~6.8 units/ml glass for the latter. Especially, alkylamino porous glass-CVB-aminoacylase showed excellent stability at pH 6~9 and temperature below 50°C, and was able to be stored for more than six months without appreciable loss of the activity.

The continuous enzyme reaction using the alkylamino porous glass-CVB-aminoacylase packed in a column was operated for 54 days at 37°C, and the half-life of the immobilized enzyme was calculated to be 78 days. From these results, it was recognized that such an immobilized aminoacylase on porous glass would be applicable in an industrial preparation of various l-amino acids from their dl-forms.