Study of Enzymatic Hydrolysis of Dilute Acid Pretreated Coconut Husk

Abstract

Coconut husk is classified as complex lignocellulosic material that contains cellulose, hemicellulose, lignin, and some other extractive compounds. Cellulose from coconut husk can be used as fermentation substrate after enzymatic hydrolysis. In contrary, lignin content from the coconut husk will act as an inhibitor in this hydrolysis process. Therefore, a pretreatment process is needed to enhance the hydrolysis of cellulose. In this study, the pretreatment was done using dilute sulfuric acid in an autoclave reactor. The pretreatment condition were varied at 80°C, 100°C, 120°C and 0.9%, 1.2%, 1.5% for temperature and acid concentration respectively. The acid pretreated coconut husk was then hydrolyzed using commercial cellulase (celluclast) and β-glucosidase (Novozyme 188). The hydrolysis time is 72 hours and the operating conditions were varied at several temperature and pH. The highest sugar concentration (1.128 g/L) was obtained at pH 4 and 50°C which is pretreated at 100°C using 1.5% acid concentration.