Dual Effect of Nonionic Surfactants on Improving the Enzymatic Hydrolysis of Lignocellulose

摘要

The mechanism of nonionic surfactants improving the cellulose conversion is still controversial. To protect enzyme stability and prevent unproductive adsorption of cellulase to lignin, which have been thought of as the chief factors for the improvement of nonionic surfactants on cellulolytic hydrolysis, were evaluated in this work. SDS-PAGE detection showed that the enzyme could not aggregate in the enzymatic hydrolysis process whether the polysorbates (Tweens) were present or not. Tweens had different capabilities to retain and even improve enzymes' activities, but these capabilities had little relation to enhancing the enzymatic hydrolysis of treated sugar cane bagasse (SCB). Tweens could increase the adsorption of cellulase to lignins and SCB samples, which was different from the current viewpoint that nonionic surfactants could impede the adsorption of cellulase to lignin. After discussion, it was proposed that the nonionic surfactants initially lubricated the access of cellulase to cellulose and subsequently combined with the free chemical groups released from lignin to impede the adsorption of cellulase to lignin with the enzymatic hydrolysis proceeding.