Antioxidant activity of lignin phenolic compounds as by-product of pretreatment process of bioethanol production from empty fruits palm bunch

Abstract

As by-product of pretreatment bioethanol production, ligno-cellulosic biomass creates an abundance of bioresidue. This work is devoted to studies the antioxidant activity of lignin that obtained from recovery process of bioethanol by-product. This by-product comes from pretreatment process of empty fruit palm bunch in acid (pH 2) and alkaline (pH 12) conditions. The samples of purified lignin were characterized by Fourier Transform Infrared (FTIR) and Particle Size Analyzer (PSA). Radical scavenging efficiency of lignin was examined by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method using quercetin as a standard. The value of IC50 showed that the lignin that was purified in acid condition (pH 2) gave the activity value in antioxidant active range (IC50 sample Lignin pH 2 = 69.41), on the other hand the lignin that was purified in alkaline condition (Lignin pH 12) did not have the activity value as an antioxidant (IC50 sample Lignin pH 12 = NA).