Adsorption Characteristics of Cellulase and beta-glucosidase to Lignin, Cellulose and Pretreated Creeping Wild Ryegrass

摘要

Enzyme adsorptions, including productive and non-productive adsorptions, are the important factors affecting the rate and degree of enzymatic hydrolysis of lignocellulosic biomass. They are directly related to the required amount of enzyme needed forachieving desired sugar yields. The non-productive adsorption of cellulase and beta-glucosidase to lignin in lignocellulosic biomass reduces enzyme availability and glucose yield. The full understanding of enzyme adsorption characteristics could reduce enzyme consumption resulting in lowered production costs for bioethanol and biochemicals through hydrolysis of lignocellulosic biomass. The objective of this study was to investigate the adsorption characteristics of cellulase and p-glucosidase to lignin,cellulose and dilute acid-pretreated Creeping Wild Ryegrass (Leymus triticoides). Cellulase and p-glucosidase were Cellucalst 1.5L from Trichoderma reesei and Novezyme 188 from Aspergitlus niger, respectively. Creeping Wild Ryegrass (CWR) was pretreatedby dilute sulfuric acid and pure cellulose was Avicel PH101 purchased from Sigma. Lignin was obtained as the residue of enzymatic hydrolysis of pretreated CWR. The enzyme amounts in the adsorption experiments were quantified by protein measurement usingBio-Rad protein reagent. Results showed that p-glucosidase had much higher affinity to lignin than cellulase did. Cellulase had much stronger adsorption capability to cellulose than p-glucosidase. Langmuir isotherms were adapted to describe the adsorption behavior of cellulase and p-glucosidase, respectively. This study provided important information for optimizing the enzymatic hydrolysis of CWR and other lignocellulosic biomass.