Immobilization of β-Glucosidase from Exiguobacterium sp. DAU5 on Chitosan Bead for Improved Enzymatic Properties

Abstract

Glutaraldehyde was used to cross-link chitosan beads to immobilize the crude enzyme β-glucosidase from Exiguobacterium sp. DAU5. The conditions for preparing cross-linking chitosan beads and immobilization such as concentration of glutaradehyde, cross-linking time, immobilization pH and time were optimized. The chitosan beads were cross-linked with 1.5% glutaraldehyde for 1.5 hr. The immobilized β-glucosidase had an overall yield of 20% and specific activity of 5.22 U/g. The optimized pH and temperature were 9.0 and 55°C, respectively. More than 80% of its activity at pH 7.0-10.0, 80% at 40°C for 2 hr and 48% at 50°C for 1 hr, were retained. However, the immobilization product showed higher pH and thermal stabilities than free enzymes. It also showed high hydrolyzing activity on soybean isoflavone glycoside linkage. These results suggest the broad application prospects of immobilization enzymes.

Development of an enzyme-immobilized support using a polyester woven fabric

“…Thus, the molecular structure of the crosslinked enzyme is modified, resulting in a decrease in the relative activity. 28,31 To determine GA crosslinking time, the GA concentration was controlled to 3% (v/v) at crosslinking times of 10-120 min (Figure 5(c)). The relative activity increased until 90 min and then decreased with increase in GA crosslinking times thereafter.…”