Optimization of enzymatic saccharification of acetic acid pretreated rice biomass using ofat method

Abstract

Rice biomass which is a comprised of rice straw and rice husk known as the most abundant and high-volume of biomass in the world. It is recorded that 1 ton of paddy harvested generate approximately 220 kg of rice husk. Meanwhile, rice straw generated from paddy is about 290 kg. Currently, rice biomass has been gained interest on the potential of converting to energy source specifically as bio-based energy fuels. This study was carried out by combining rice straw and rice husk in 3:1 mainly to obtain the optimum condition in synthesis reducing sugar. This rice biomass was undergone acetic acid pretreatment beforehand at 170℃ in 20 minutes by using 4% (v/v) acetic acid in a reactor. This is to study any changes on the rice biomass before and after the pretreatment. Result stated that lignin and hemicellulose are removed after the pretreatment. Characteristic, functional group and morphological structure changes was observed using Fourier Transform Infrared (FTIR) and Scanning Electron Microscopy (SEM). Based on the FTIR and SEM, there are changes in the physical and structure happened on the rice biomass after pretreatment as the pretreated sample illustrated uncovered of cellulose. Reducing sugar was optimized by considering three parameters which are time of incubation, pH and usage of Trichoderma Reesei as enzyme loading via One Factor at One Time (OFAT) with 27 runs. Experiment using OFAT method was done by changing one factor at a time and keeping others fixed. From the experiment, it showed that reducing sugar concentration was increased at pH 5 with 2.5% enzyme concentration at 72 hours.