Immobilization of Chitinase Produced from Lysobacter enzymogenes MG18S on Chitosan Beads = Immobilization of Chitinase Produced from Lysobacter enzymogenes MG18S on Chitosan Beads

다국어 초록 (Multilingual Abstract)

Chitosan beads were prepared by cross-linking with glutaraldehyde and used for the immobilization of crude enzyme produced by the chitinase-producing bacterium Lysobacter enzymogenes MG18S. The optimal process for immobilization was as follows: a 10 mL volume of wet 2.5% chitosan beads was added to tubes containing 10mL 0.1 M phosphate buffer (pH 7.04) in a 5% solution of glutaraldehyde (GA). Then, 1mL of enzyme solution (238ug/mL) containing 0.1 M phosphate buffer (pH 6.45) was added to 1mL of glutaraldehyde treated wet chitosan beads (20 beads). Chitinase activities of 2.5% chitosan beads with GA 0% and GA 5% were 41.2 and 6.5 units/mg protein, respectively, at 2 h of reaction using hyphae of R. solani KACC 40151 as the substrate. The relative activity of 2.5% chitosan beads with GA 0% decreased with processing time during a 6 h period, while the activity of 2.5% chitosan beads with GA 5% was maintained until 4 h, and then decreased at 6 h after initiation of the reaction. Chitinase activities of 2% and 7% chitosan beads with GA 0% were 89.2 and 110.5 units/mg protein, respectively, at 2 h of reaction time. The relative activity of 2% chitosan beads rapidly decreased at GA 1% after reaction for 2 h, while that of 7% chitosan beads slowly decreased with increasing concentrations of glutaraldehyde. Concerning the operational stability of the immobilized enzyme, chitinase activities of 7% chitosan beads with GA 0% and 10% were 45.4 and 2.1 units/mg protein, respectively, at 2 h of reaction time using colloidal chitin as a substrate. The chitinase activities of 7% chitosan beads with GA 0% and GA 10% were 1.3 and 0.3 units/mg protein, respectively, at 20 h of reaction time. These results indicate that immobilization of enzyme on chitosan beads will be an effective method for the prevention and biological control of phytopathogens in the field.