Physical-chemical Characterization of Lignocellulosic Materials of Interest to Bioethanol Production

Abstract

The knowledge of the chemical composition of biomass feedstocks is very important in order to decide what lignocellulosic material to be used in the industrial process and the associated pretreatment to bioethanol production. In this context, the present work applied an analytical methodology of chemical characterization, developed for sugarcane bagasse, to other biomasses, namely, sugarcane straw, bamboo, bean stalk, residue from the extraction of castor oil, sape grass, wheat straw, African palm rachis, elephant grass and Agave tequilana. Chemical composition (cellulose, hemicellulose and lignin) of the raw materials was determined by the acid hydrolysis (H2SO4 72%) of theses extractives-free materials. Carbohydrates, organic acids and degradation products were determined by HPLC. Lignin and phenolics were analyzed by gravimetry and spectroscopy procedures, respectively. Results showed that, among the materials studied, the sugarcane bagasse had the higher amount of cellulose (43.8%) and the sugarcane straw had the higher amount of hemicellulose (32.4%) justifying the interest of apply these biomasses as raw materials for the production of cellulosic ethanol. Other biomasses presented cellulose composition varying between 31.8 and 41.7 %, hemicellulose between 21.2 and 28.6 %, and lignin from 20.6 to 33.6 %. Extractives showed more abundant in sape grass (18.7 %) and were removed before the composition analysis to avoid interferences in lignin quantification.