BOOSTING ENZYMATIC HYDROLYSIS OF PRESSURIZED AMMONIUM HYDROXIDE PRETREATED EMPTY FRUIT BUNCH USING RESPONSE SURFACE METHODOLOGY

Abstract

Oil palm Empty Fruit Bunch (EFB) was pretreated using Pressurized Ammonium Hydroxide (PAH) and was employed as Lignocellulosic Biomass(LCB) substrate for the investigation on the monomeric fermentable sugar production using the enzymatic hydrolysis process. Cellulose saccharification in enzymatic hydrolysis into a high yield fermentable sugar is an important step in Biochemical Conversion Technology (BCT). In order to determine the optimum variable conditions that can produce a high yield of fermentable sugar, a statistical approach using Response Surface Methodology (RSM) was performed in this study. Three independent variables, enzyme loading (15-50 FPU/g glucan), hydrolysis temperature (45-60°C), and agitation of the hydrolysis process (100-180 rpm) were investigated at five different levels (-α,-1, 0, +1, +α) of operating conditions and the experimental conditions were randomly setup using the Design of Experiment software. The regression models indicated that R 2 for glucose and xylose concentration was 95 and 88% showing the experimental variations were well defined by the models. For the lack of fit test, with p-values > 0.05 for both concentration sugars, 0.218 for glucose and 0.055 for xylose, it proves that the model was significant to the prediction models. The optimal conditions for the enzymatic hydrolysis of the EFB were determined at 32.5 FPU/g of glucan of enzyme loading, 50°C of hydrolysis temperature, and 140 rpm of agitation speed. The validation of the model at the optimum conditions produced a maximum glucose concentration of 8.78 ± 0.01 g/L (conversion of 81.7 ± 0.02 %, and yield of 332.95 ± 0.98 g/kg dry EFB), with a corresponding xylose concentration of 4.40 ± 0.01 g/L (conversion of 57 ± 0.35% and yield of 173.72 g/kg dry EFB).

Keywords

• Ammonia
• Empty fruit bunch
• Lignocellulosic
• Pressurized
• Pretreatment
• RSM
• Sugar concentration