Dextran degradation by sonoenzymolysis: Degradation rate, molecular weight, mass fraction, and degradation kinetics

To study dextran degradation by sonoenzymolysis, the degradation rate, the change of molecular weight, the mass fractions of fragments of certain molecular weight, and the degradation kinetics were analyzed and compared with the corresponding parameters under ultrasonic and enzymolysis treatments. The degradation rate improved greatly and the time required to stabilize the rate was shortened compared with ultrasonic treatment, for example, more than 120 min was needed at 4 W/mL for ultrasonic treatment before stabilization with the degradation rate of 77.41%, whereas 80 min was needed for sonoenzymolysis treatment with the degradation rate of 91.44%. A lower molecular weight limit was established (7.15 × 104 Da at 4 W/mL for sonoenzymolysis treatment compared with 19.61 × 104 Da at 4 W/mL for ultrasonic treatment), with decreased time to approach the new limiting molecular weight (80 min compared with more than 120 min). The mass fraction of 104–105 Da fragment increased (61.02% at 4 W/mL for sonoenzymolysis treatment compared with 42.98% at 4 W/mL for ultrasonic treatment) and the dextran degradation kinetics for sonoenzymolysis under lower ultrasonic intensity fitted the Malhotra model well. Sonoenzymolysis treatment at the ultrasonic intensity of 4 W/mL for 80 min resulted in more 104–105 Da fragments in a shorter time. The results indicated that sonoenzymolysis can be applied as an efficient method to obtain clinical dextran.