Immobilization of Cellulase on a Reversibly Soluble−Insoluble Support: Properties and Application

Abstract

Cellulase was coupled to N-succinyl-chitosan (NSC) showing soluble-insoluble characteristics with pH change. Cellulase immobilized on NSC (NSCC) is in a soluble state during the enzyme reaction, yet can be recovered in its insoluble form by lowering the pH of the reaction solution after the reaction. NSCC was obtained under the optimized immobilization conditions of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) 10 mg, cellulase 15 mg, and pH 5.0. The retention activity of the immobilized cellulase was found to be 48.8%. The effects of pH and temperature on the activity and stability of NSCC were studied and compared with those of free cellulase. The optimum temperature and pH of NSCC was 45 degrees C and 4.0, respectively, which was found unchanged compared with the free one. The stability of cellulase against change in the pH and temperature was improved by the immobilization. The effectiveness of employing NSCC for extracting flavonoids from Ginkgo biloba leaf powder was investigated. Results showed that NSCC enhanced extraction yield up to 2.35-fold when compared with the conventional method. Moreover, NSCC retained 83.5% of its initial activity after five batches of hydrolysis reaction.

Immobilization of Commercial Cellulase and Xylanase by Different Methods Using Two Polymeric Supports

“…At neutral values (pH 6.0), reticulation-immobilized cellulase lost all activity, whilst free and adsorption-immobilized cellulase retained around 50% and 60%, respectively, of its initial activity. Similar findings are reported by Zhou [26] for cellulase immobilized on N-succinyl-chitosan. In all cases, changes in behavior as a function of pH may depend on the charge both of the enzyme and of the solid support.…”

Immobilization of cellulase onto a recyclable thermo-responsive polymer as bioconjugate

“…Some pH-responsive [10][11][12] and thermo-responsive polymers [13][14][15][16] reported have been used to immobilize enzymes. Specifically, polymers with lower critical solution temperature (LCST) behavior are interesting supports for enzymes [11,17,18]. The LCST behavior of certain thermoresponsive polymers can be tuned above the optimum temperature of enzyme activity.…”

Modeling the Effect of pH and Temperature for Cellulases Immobilized on Enzymogel Nanoparticles

“…Again, no interaction was studied with temperature effects. Another study also found that immobilization had little effect on comparative immobilized cellulase activity at pH of 6 or below and had somewhat higher relative activity at higher pH values [33]. Immobilized enzymes had higher thermostability, but interaction between pH and temperature was not tested in either study.…”