Low-frequency Ultrasound with Short Application Time Improves Cellulase Activity and Reducing Sugars Release

In this study, we investigated the effect of ultrasound (US) on the activity of commercial cellulase (Celluclast (R) 1.5 L) in the absence and in the presence of a cellulosic substrate (Avicel (R), 2% w.v(-1)) using a central composite rotatable design. Sonication time (10 to 330 s), US intensity (120.6 to 263.7 W cm(-2)), and reaction temperature (25 to 50 degrees C) were varied using a horn-type ultrasound reactor, and endoglucanase (CMCase) and total cellulase (FPase) activities were determined. US intensity had a positive effect on enzyme activity. Under optimal conditions (170 s, 180.8 W cm(-2), and 25 degrees C), CMCase activity was 13% higher than that of the control. In the presence of substrate, CMCase activity increased by 33.87% and K-M reduced by 23% in relation to that of the control. The theoretical yield of cellulose was 42.08%. Cellulase activity can be improved by US treatment to maximize productivity gains and reduce costs in second-generation ethanol production, by the action of a low-frequency ultrasound with a short ultrasonication time of application.