Hydrolysis of Cellulose from Oil Palm Empty Fruit Bunch using Aspergillus niger

Abstract

Oil palm empty fruit bunch (OPEFB) constitutes a great source of lignocellulosic biomass, mainly comprising of 66.97 % of holocellulose (cellulose and hemicellulose) and 24.45 % of lignin. This present work aimed to hydrolyze cellulose present in OPEFB to form glucose with the aid of Aspergillus niger. A. niger is a type of filamentous fungi able to produce cellulase, a multi-enzyme complex consisting of an endoglucanase, exoglucanase, and β-glucosidase, able to converting cellulose into glucose. The glucose produced is then fermented to produce bioethanol. The present study compared hydrolytic activity of cellulose between OPEFB with pretreatment using NaOH 10 % and OPEFB without pretreatment, concerning temperature, pH, and hydrolysis time. The concentration of reducing sugar derived from cellulosic hydrolysis was determined by using a glucose assay of 3.5-dinitrosalicylic acid. The results showed that the optimum temperature for hydrolysis of cellulose OPEFB (pretreated and untreated) was at 40 °C and the optimum pH was 5.0 for OPEFB-untreated and 5.5 for OPEFB-pretreated. Hydrolysis of cellulose at 40 °C and 3 d yielded reducing sugar 13.01 mg mL−1 and 1.16 mg mL−1 for OPEFB-untreated and OPEFB-pretreated, respectively.

Keywords

• 2nd bioethanol generation
• biomass
• cellulose hydrolysis
• lignin
• renewable energy