Statistical optimization for deconstruction of poplar substrate by dilute sulfuric acid for bioethanol production

Abstract

In this study, response surface methodology was used to study the effects of H2SO4, concentrations, substrate loading and residence time on liberation of reducing sugars (RS), total sugars (TS) and total phenolic compounds from poplar leaves and twigs. Box-Behnken design with three variables and three levels showed maximum release of total phenolic compounds (57.39 mg/ml) corresponding to 0.8% H2SO4 concentration, 15% substrate level with residence time of 4 h. Under these conditions, the TS and RS released up to 161.20 and 5.24 mg/ml, respectively. Analysis of the pretreated substrate by Fourier transform infra-red and X-ray diffraction revealed the effectiveness of pretreatment conditions. Second-order polynomial equation using analysis of variance was employed for analyzing the results. The proposed model was found very significant with F-value of 48.39. The R2 and adjusted R2 values also revealed the accuracy of predicted response. (Image Presented).