Cellulase adsorption on pretreated sugarcane bagasse during enzymatic hydrolysis

Abstract

The enzymatic hydrolysis of lignocellulosic biomass has become attractive for obtaining ethanol. Therefore, optimizing its conditions and revealing the main influencing factors are essential for an effective design. In this sense, this study evaluated the influence of cellulose conversion on the Langmuir isotherm parameters in cellulase adsorption on sugarcane bagasse pretreated by hydrothermal and organosolv methods. The adsorption isotherm assays were performed with commercial cellulase from Trichoderma reesei in Erlenmeyer flasks stirred at 150 rpm and 50 °C. Isotherms were determined for enzymatic hydrolysis substrate samples of hydrothermal bagasse (HB) and organosolv bagasse (OB) at 0, 1, 6, and 18 h, respectively. The Langmuir model represented well the experimental data for the cellulose–cellulase system. The study of cellulase adsorption on HB and OB demonstrated that the maximum adsorption capacity (Emax) decreased during the reaction. From 0 to 18 h of hydrolysis, the value of Emax decreased from 37 ± 3 to 23 ± 2 mg cellulase/g HB and from 29 ± 1 to 25 ± 2 mg cellulase/g OB. Therefore, the adsorption of cellulase on a substrate varied during hydrolysis and its representation was expressed by an empirical equation related to the cellulose conversion and the Langmuir parameters.