Title
Different treatments of pearl millet biomass for cellulose recovery: effects on lignocellulosic composition
Authors
ALINE P. DRESCH, MATHEUS CAVALI, DAVID F. DOS SANTOS, ODINEI FOGOLARI, VÂNIA Z. PINTO, GUILHERME M. MIBIELLI and JOÃO P. BENDER

Received December 7, 2022
Published Volume 57 Issue 3-4 March-April
Keywords waste valorization, Pennisetum glaucum, oxalic acid, characterization

Abstract
The objective of this study was to recover cellulose from pearl millet biomass through chemical (alkaline and acidic) pretreatments. The cellulosic fraction was characterized by Fourier transform spectroscopy (FTIR), X-ray diffraction (XRD), and Raman spectroscopy. The cellulose-rich fraction presented 100% and 99.86% of lignin and hemicelluloses removal, respectively, and a high crystallinity index of 82.43% after two 4-hour alkaline extractions with 4% NaOH, followed by 2 h extraction with 5% C2H2O4 in an autoclave at a temperature of 125.6 °C and 1.4 bar. According to the FTIR, XRD, and Raman spectroscopy analyses, the removal of hemicelluloses and lignin from pearl millet biomass was confirmed, which indicated the efficiency of the pretreatments evaluated. Therefore, the results presented in this study should contribute to improving the efficiency of the fractionation processes of lignocellulosic biomasses.