The partially purified CGTase was entrapped in mixed alginategelatin
gel beads following the method of Choi et al.[6] with a slight
modification. CGTase was mixed with alginate-gelatin paste containing
3% (w/v) alginate and 3% (w/v) gelatin melted in 50 mM
phosphate buffer, pH 7.0. The mixture was extruded through a
2 mm needle using a peristaltic pump at 300 rpm flow rate into
177 mM CaCl2 solution under constant stirring to form the beads.
The beads were allowed to harden in the CaCl2 solution at 4 ◦C for
24 h with stirring. The CaCl2 solution was removed by filtration
and the beads were washed twice with phosphate buffer (50 mM,
pH 7.0). The immobilized CGTase was filtered and stored at 4 ◦C.
The entrapped enzyme with an immobilization yield of 87.5% was
then obtained. After incubation attemperature of 50 ◦C for 12 h,the
immobilized CGTase retained more than 50% of the initial activity
while the free CGTase retained only 30% (data not shown).