Adsorption Characteristics of Cellulase and β-glucosidase to
Pretreated Sugarcane Bagasse
Machado, D. L; Moreira Neto, J; da Costa, A.C
School of chemical Engineering, State University of Campinas, Brazil.
Lignocellulose is a potential substrate for ethanol production. In Brazil the sugarcane bagasse, which is a complex lignocellulosic material, is the major by product of the sugarcane industry. Current technology for conversion of biomass to ethanol is an enzyme-based biochemical process. The rate and degree of enzymatic hydrolysis of lignocellulosic substrates are affected by many parameters, including productive and non-productive adsorptions of cellulases. The non-productive adsorption of cellulase and β-glucosidase occurs in lignin in the lignocellulosic biomass that reduces enzyme availability and glucose yield. Then the objective of this study was to investigate the adsorption characteristics of cellulase and β-glucosidase to lignin, and hydrothermal-pretreated sugarcane bagasse. The experiments were performed using two commercial enzyme preparations, cellulase from Trichoderma reesei (Sigma-Aldrich, ATCC 26 921) and β-glucosidase from Aspergillus niger, (Novozyme 188). The enzyme amounts in the adsorption experiments were quantified by Bradford protein assay. The adsorption behavior of cellulase and β-glucosidase was described by Langmuir isotherms. The studies of kinetic and isotherm adsorption were performed using 1% (w/v), 5% (w/v) and 10% (w/v) of bagasse The parameters Emax (maximal adsorption enzyme/substrate) and Ead (enzyme adsorbed/g substrate) present in the Langmuir equation were estimated by nonlinear regression. This study is relevant to explain how the adsorption process interferes with rate and the yield of the enzymatic hydrolysis of lignocellulosic biomass at high solid loading.