Response surface methodology (RSM) for assessing the effects of pretreatment, feedstock, and enzyme complex association on cellulose hydrolysis
Leila Maria Aguilera Campos, Heloise O. M. A. Moura, Antonio José Gonçalves Cruz, Samira Maria Nonato de Assumpção, Luciene Santos de Carvalho, Luiz Antônio Magalhães Pontes
Abstract
The enzymatic hydrolysis of sugarcane bagasse cellulose (SBC) was performed after acid/peroxide-alkali (APA) pretreatment, soda/AQ pulping, and bleaching steps for producing glucose. Cellic® CTec3 (CT) and Celluclast®1.5L (CL) complexes were evaluated in both individual and mixed systems for observing their influence in cellulose conversion. Deconvolution of XRD patterns and SEM images proved the low crystallinity and high accessibility of SBC, thus being able to provide significantly higher glucose yield than the commercial cellulose with predominant Iβ polymorphism. The analysis of variance (ANOVA) and the response surface methodology (RSM), applied to a full factorial 24 design of experiments built for assessing the activity of CT and CL enzymes together in the hydrolytic system, were accurate in describing that the feedstock (SBC or commercial cellulose) and the treatment of cellulose are the factors with major effect on the saccharification efficiency (F = 744.12, p < 0.0001), thus predicting 53.71 g/L maximum glucose yield for the experimental conditions studied (near to the maximum yield reached, 55.77%) when using SBC, more than double the conversion reached for commercial cellulose, and showing the cooperative work of both complexes together for converting cellulose.