Impact of NaOH Concentration and Pretreatment Time on the Lignocellulose Composition of Sweet Sorghum Bagasse for Second-Generation Bioethanol Production

Abstract

Using lignocellulosic materials as raw materials to manufacture alternative fuels second generation (G2) is a solution for substituting fossil fuels. One source of lignocellulose is sweet sorghum bagasse. The pretreatment process is essential to increase the percentage of cellulose contained in the material before the fermentation and hydrolysis. So, this study aims to evaluate the NaOH concentration and pretreatment time effect on the lignocellulose composition of pretreated sweet sorghum bagasse. The Factorial Completely Randomized Design (FCRD) experimental design was chosen with 2 independent factors, namely NaOH concentration with 2 levels (4% and 8%) and the pretreatment time with 2 levels (10 min and 30 min). The observed responses data was analyzed using a Two-Way analysis of variance (ANOVA) at a 95% confidence level, and if there were any significant differences, followed by Duncan multiple range tests (DMRT). The results showed that both independent factors affected (p-value ˂ 0.05) the lignocellulose composition of pretreated sweet sorghum bagasse, especially in lignin reduction. The best combination in pretreated sweet sorghum bagasse was found at 8% NaOH concentration and 30 min of the pretreatment time. In this condition, the cellulose increased by 13.56%, and hemicellulose and lignin decreased by 3.09% and 10.12%, respectively, to the raw material.

Keywords: Bioethanol, Lignin, Lignocelullose Composition, NaOH concentration