Effect of a Nonionic Surfactant on Enzymatic Hydrolysis of Lignocellulose Based on Lignocellulosic Features and Enzyme Adsorption

Abstract

Reduction in the adsorption of cellulase onto lignin has been thought to be the common reason for the improvement of enzymatic hydrolysis of lignocellulose (EHLC) by a nonionic surfactant (NIS). Few research studies have focused on the relationship between lignocellulosic features and NIS for improving EHLC. This study investigated the impact of Tween20 on the enzymatic hydrolysis and enzyme adsorption of acid-treated and alkali-treated sugarcane bagasse (SCB), cypress, and Pterocarpus soyauxii (PS) with and without being ground. After addition of Tween20, the adsorption of cellulase onto unground and ground alkali-treated SCB increased, and the unground acid-treated SCB exhibited little change in adsorption cellulase, while other unground and ground, treated samples showed decreased cellulase adsorption. Tween20 could improve the enzymatic hydrolysis of acid-treated SCB, while it had little influence on the enzymatic hydrolysis of other treated materials. After being ground, both cellulase adsorption and enzymatic hydrolysis of treated lignocelluloses increased, and Tween20 could enhance the enzymatic hydrolysis of acid-treated materials while hardly affected the enzymatic hydrolysis of alkali-treated materials. This indicated that the promotion effect of Tween20 on enzymatic hydrolysis of treated lignocellulose could not be mainly ascribed to the hindrance of Tween20 to cellulase adsorption on lignin but was related to the lignocellulosic features such as hemicellulose removal and surface morphology changes.