Kinetics study of enzymatic hydrolysis of Paulownia by dilute acid, alkali, and ultrasonic-assisted alkali pretreatments

摘要

Paulownia, a fast-growing and high-fiber plant (cellulose: 41.66% and hemicellulose: 19.61%), has the potential to serve as an interesting source for production of bioethanol. The aim of this paper is to study and compare the kinetics of enzymatic hydrolysis of Paulownia pretreated by dilute acid (DA), alkali (AL) and ultrasonic-assisted alkali (UA). The enzymatic hydrolysis was performed at 50A degrees C, atmospheric pressure with 40 FPU/g-cellulose cellulase and 80 CBU/g-cellulose cellobiase. The hydrolysis process can be successfully described by the Michaelis-Menten model under the three pretreatment conditions. Due to the high removal of lignin and increased porosity of the substrate, UA pretreatment is proved to be the most effective method in improving enzymatic saccharification, followed by DA pretreatment and alkali (AL) pretreatment. Inhibition constant K (I) of all experiments (DA: 2.16 g/L, AL: 3.12 g/L and UA: 1.83 g/L) suggests that glucose has a strong inhibition for enzymatic hydrolysis, for lower K (I) is proportional to higher inhibition performance. The experimental date fits well with kinetics model. This indicates that the model is suitable for performance monitoring, conditions optimization and process control at full-scale studies.