Lignin and cellulose changes of betung bamboo (Dendrocalamus asper) pretreated microwave heating

Abstract

This study highlighted the effect of microwave pretreatment on betung bamboo on the chemical structural and morphological changes. The hydrothermal condition was performed in varying power loading (330, 550, and 770 W) and microwave irradition time (5-12.5 min). FTIR spectroscopy, X-Ray diffraction and SEM-EDS analysis were utilized to confirm the characteristic changes after pretreatment. The results showed that the severe pretreatment condition tended to increase the carbohydrate losses. From FTIR spectra, microwave pretreatment tended to decrease absorbancy of functional group bands. After microwave pretreatment for 12.5 min (770 W), the band around 1736 cm-1 (C=O in xylan) disappeared in the samples. The syringil propane unit was lower than that of guaiacyl lignin under microwave pretreatment. The disruption of the structure of the cell wall increased the accessibility of cellulase to lignocellulose. Except microwaving for 5 min (330 W), the microwave heating caused carbon and oxygen increasing compared to untreated samples. The increase in crystallinity index of pretreated bamboo suggested the selective degradation of amorphous components.