Optimization by response surface methodology of the enzymatic hydrolysis of non-pretreated agave bagasse with binary mixtures of commercial enzymatic preparations

Abstract

Optimum conditions for the enzymatic hydrolysis of non-pretreated agave bagasse using two binary mixtures of commercial enzymatic preparations with cellulase and hemicellulase activities (Celluclast 1.5 L/Viscozyme L and Cellic® Ctec2/Cellic® Htec2) were determined. The optimization was carried out by using the response surface methodology (RSM). Two response variables were analyzed, hydrolysate reducing sugar concentration (RS; mg/mL) and saccharification yield (SY; mg RS/g bagasse). Higher RS concentration (27.58 ± 3.68 mg/mL) and SY (312.54 ± 46.89 mg RS/g bagasse) were obtained with the mixture Celluclast 1.5 L and Viscozyme L, even when compared with lignocellulosic biomass specialized enzyme mixture of Cellic® Ctec2 and Cellic® Htec2. The RS concentration in the hydrolysate and the SY obtained under optimal conditions for both enzymatic mixtures were higher when compared with previous results. In the case of the mixture Cellic® Ctec2 and Cellic® Htec2, an increase of 5.4- and 2.2-times for the RS concentration and SY were respectively observed, while in the case of the mixture Celluclast 1.5 L and Viscozyme L, an increase of 2- and 1.6-times were detected. The degree of synergy (DS) for the enzymatic hydrolysis was 1.52 (with SY as response variable) and 1.65 (with RS concentration as response variable) for the mixture of Celluclast 1.5 L and Viscozyme L, which indicates the synergism between the enzymes present in this binary mixture.