Improvement of cellulose conversion caused by the protection of Tween-80 on the adsorbed cellulase

For the hydrolysis of pure cellulose, the positive effect of Tween-80 was controversial. In this study, it was found that Tween-80 had little effect on pure cellulose conversion under the shaking speed of 0 and 100 rpm. However, when the shaking speed increased to 180 rpm, Tween-80 resulted in an obvious improvement of cellulose conversion. The mechanism of Tween-80 effect was investigated from three aspects: protecting free cellulase from deactivation, decreasing cellulase proteins adsorption and reducing the cellulase deactivation during the interaction between enzyme and substrate. Tween-80 did not show more positive effects at high speed in protecting free cellulase against deactivation and decreasing cellulase proteins adsorption. From the studies of endoglucanase and exoglucanase relative activities in the supernatant of hydrolysis, it was found that the improved conversion of cellulose with Tween-80 at high shaking speed was mainly due to the reduction of the adsorbed cellulase deactivation resulting from enzyme-substrate interaction. (C) 2011 Elsevier B.V. All rights reserved.