Enhanced enzymatic hydrolysis of rice straw pretreated by alkali assisted with photocatalysis technology

摘要

BACKGROUND: The fermentable sugars in lignocellulose are derived from cellulose and hemicellulose, which are not readilyaccessible to enzymatic hydrolysis because of their biological resistance, so that pretreatment of lignocellulose is needed forthis process. In this work, a novel lignocellulose pretreatment method using alkali solution assisted by photocatalysis wasinvestigated. RESULTS: The reaction conditions of nano-TiO_2 dosage and photocatalysis time were optimized at 2 g L-1 and 1 h, respectively.After pretreatment under these conditions, cellulose in rice straw was increased from 37.5% to 71.5%, and lignin decreasedfrom 18.5% to 9.0%. The results of X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and scanning electron microscopy(SEM) analysis showed that the physical properties and microstructure of the straw were changed by this pretreatment, whichfavored the following enzymatic hydrolysis. The enzymatic hydrolysis rate of the straw pretreated using this technology wasverified to be 73.96%, which was 2.56 times higher than that obtained with the alkali procedure. CONCLUSION: The proposed photocatalysis pretreatment technology was more efficient at degrading the lignin andhemicellulose in rice straw than alkali pretreatment, making it more readily available for the following enzymatic hydrolysisprocess.